HitachiHVB_Manual_FinalCopy1_28Septv1

OPERATION AND INSTALLATION MANUAL

HS123/145 kV- 40 kA -2000/3000/3125 A

DUAL RATED ANSI / IEC GAS CIRCUIT BREAKER

Instruction Manual Book No. 99-0145-40HSE
REVISION 12, JUNE 2015

http://hvbi.hitachi.us/

Table of Contents

CHAPTER 1. SAFETY .......................................................................................................... 1-6

1.1 INTRODUCTION..............................................................................................................................1-6
1.2 GENERAL SAFETY .......................................................................................................................... 1-6
1.3 SPECIFIC SAFETY .............................................................................................................................1-6
1.4 SULFUR-HEXAFLUORIDE (SF6) GAS ..................................................................................................1-7
1.5 SERVICE SAFETY..............................................................................................................................1-8

CHAPTER 2. GENERAL INFORMATION ............................................................................... 2-1

2.1 DESCRIPTION OF BREAKER .............................................................................................................2-1

2.1.1 INTERRUPTER ....................................................................................................2-1
2.1.2 PORCELAIN INSULATOR/CONDUCTOR/GAS TANK ASSEMBLY ...........................................2-1
2.1.3 MECHANISM SPRING-SPRING .................................................................................2-1
2.1.3.1 CHARGING SYSTEM AND CLOSING SPRING........................................................................2-1
2.1.3.2 CLOSING OPERATION .............................................................................................2-1
2.1.3.3 TRIPPING OPERATION.............................................................................................2-1
2.1.4 INTERPHASE LINKAGE ..........................................................................................2-1

2.2 GENERAL CONTROL INFORMATION ................................................................................................2-1

2.2.1 INITIAL BREAKER WIRING.......................................................................................2-1
2.2.1.1 CONTROL/MECHANISM CABINET .................................................................................2-1
2.2.1.2 CONTROL CIRCUITS................................................................................................2-1
2.2.1.3 CLOSING OPERATION..............................................................................................2-1
2.2.1.4 OPENING OPERATION .............................................................................................2-1
2.2.1.5 ADDITIONAL CONTROL FEATURES .................................................................................2-1

2.3 BREAKER OPERATION .....................................................................................................................2-1

2.3.1 MECHANISM.......................................................................................................2-1
2.3.2 ARC INTERRUPTION PRINCIPLE.................................................................................2-1

CHAPTER 3. INSTALLATION ............................................................................................. 3-11

3.1 PACKING SHIPPING AND RECEIVING ..............................................................................................3-11
3.2 TOOLS AND TESTING EQUIPMENT .................................................................................................3-11
3.2.1 TOOLS........................................................................................................................................3-11
3.2.2 TESTING EQUIPMENT .................................................................................................................3-33
3.3 STORAGE ......................................................................................................................................3-33
3.3.1 BREAKER ASSEMBLY ...................................................................................................................3-33
3.3.2 ALL PARTS BOXES .......................................................................................................................3-44
3.4 ASSEMBLY INFORMATION .............................................................................................................3-44
3.4.1 PRELIMINARY INFORMATION .....................................................................................................3-44
3.4.2 GENERAL ASSEMBLY PROCEDURES .............................................................................................3-55
3.5 INSTALLATION TESTING.................................................................................................................3-55
3.5.1 GENERAL....................................................................................................................................3-55
3.5.2 MECHANICAL TESTS ...................................................................................................................3-66
3.5.2.1 EXTERNAL STROKE AND WIPE MEASUREMENT.......................................................................................3-66
3.5.2.2 CIRCUIT BREAKER OPERATIONAL TEST.................................................................................................3-77

1

3.5.3 ELECTRICAL TESTS .......................................................................................................................3-88
3.5.3.1 CONTACT RESISTANCE, (DUCTOR TEST) ..............................................................................................3-88
3.5.3.2 INSULATION RESISTANCE, (1000 V MEGGER TEST) ...............................................................................3-99
3.6 INSTALLATION & ASSEMBLY CHECK-LIST.........................................................................................3-11

CHAPTER 4. SF6 GAS SYSTEM ............................................................................................ 4-1

4.1 GENERAL INFORMATION..................................................................................................................4-1
4.2A SF6 TEMPERATURE COMPENSATED PRESSURE GAUGE ...................................................................4-1
4.3A FILLING WITH SF6 GAS ...................................................................................................................4-3
4.4A SF6 LEAK RATE AND LEAK DETECTION.............................................................................................4-4
4.5A SF6 TEMPERATURE COMPENSATED GAS MONITORING SYSTEM .....................................................4-5
4.2B TEMPERATURE COMPENSATED PRESSURE SWITCH ........................................................................4-6
4.3B FILLING WITH SF6 GAS ...................................................................................................................4-7
4.4B SF6 LEAK RATE AND LEAK DETECTION .............................................................................................4-9
4.5B SF6 TEMPERATURE COMPENSATED GAS MONITORING SYSTEM......................................................4-9
4.6 TESTING SF6 SYSTEM PRESSURE .....................................................................................................4-10
4.7 OPTIONAL PRESSURE SYSTEM - INDIVIDUAL PHASE MONITORING...................................................4-12
4.8 PULLING VACUUM .........................................................................................................................4-13
4.9 O - RINGS AND GASKETS INSTALLATION ..........................................................................................4-13
4.10 SWAGELOK GAS SEAL SYSTEM ......................................................................................................4-15
4.11 RUPTURE DISK .............................................................................................................................4-16
4.11.1 RUPTURE DISK REPLACEMENT...................................................................................................4-17
4.12 CRANKBOX ROTATING O-RING SEALS............................................................................................4-17

CHAPTER 5. MAINTENANCE .............................................................................................. 5-1

5.1 SAFETY NOTE ...................................................................................................................................5-1
5.2 REPLACEMENT PARTS ......................................................................................................................5-1
5.3 GENERAL NOTES ..............................................................................................................................5-1
5.4 INSPECTION AND MAINTENANCE SCHEDULE ....................................................................................5-2
5.4.1 ROUTINE INSPECTION AND MAINTENANCE ........................................... ERROR! BOOKMARK NOT DEFINED.
5.4.1.1 GENERAL.............................................................................................. ERROR! BOOKMARK NOT DEFINED.
5.4.1.2 ROUTINE INSPECTION AND MAINTENANCE DETAILS.................................................................................5-6
5.4.1.3 PATROLLING INSPECTION AND MAINENANCE DETAILS ...............................................................................5-4
5.4.2 PERIODIC INSPECTION AND MAINTENANCE...................................................................................5-8
5.4.2.1 GENERAL......................................................................................................................................5-8
5.4.2.2 PERIODIC INSPECTION AND MAINTENANCE DETAILS ................................................................................5-9

APPENDIX......................................................................................................................... 1

APPENDIX 1. TORQUE VALUE CHART .......................................................................................................1
APPENDIX 2. OPERATION TRAVEL CURVES ...............................................................................................2
2.1 CLOSE................................................................................................................................................2
2.2. OPEN.................................................................................................................................................5
2.3 TRIP FREE............................................................................................................................................8
2.4 RECLOSE ...........................................................................................................................................11

2

REVISION HISTORY ......................................................................................................... 14
3

Preface
This manual covers the installation and operation of the HITACHI HVB, Inc. 123/145kV/40kA
gang operated puffer circuit breaker. These instructions should be reviewed thoroughly to ensure
proper understanding prior to performing any work on the equipment.
Prior to performing any work on the circuit breaker, be absolutely sure to review the “SAFETY”
section of this manual and ensure that all personnel scheduled to work on the equipment
are familiar with the recommendations of that section.
The illustrations and information provided in this manual are designed to cover the normal
customer requirements. However, this manual may not cover some customer-required special
items.
If, for any reason, a problem were to occur which is not covered by this manual, HITACHI HVB,
Inc. would request that the following information’s are made available:
Customer/Company Name:
Job Site Name (substation):
Circuit Breaker Rating (123/145kV/40kA):
Circuit Breaker Serial Number (main nameplate):

To contact HVB, use the following contact information:
HITACHI HVB, Inc.
7250 McGinnis Ferry Road
Suwanee, GA 30024
United States of America
Phone: (770) 495-1755
Toll Free: (866) 362 0798
Fax: (770) 623-9214

4

Symbols and Details:

WARNING Indicates a potentially hazardous situation which,
if not avoided, could result in death or serious injury. A
statement or event that warns of something or that serves as
a cautionary.
CAUTION Indicates a potentially hazardous situation which, if
not avoided, could result in minor or moderate injury. Care
taken to avoid danger or mistakes.
NOTE Indicates about the particular situation which should be
taken carefully, a brief record of points or ideas written down
as an aid to memory.
NOTICE used without the safety alert symbol indicates a
potentially hazardous situation which, the fact of observing or
paying attention to something.
DANGER This is the safety alert symbol. It is used to alert you
to potential personal injury hazards, Obey all safety messages
that follow this symbol to avoid possible injury or death.
SAFETY This is the safety alert symbol. It is used to alert you
to the condition of being protected from or unlikely to cause
danger, risk, or injury.

5

Chapter 1. Safety

Chapter 1 SAFETY

1.1 INTRODUCTION

To the extent required, the products described herein meets applicable ANSI, IEC, IEEE and
NEMA standards as of the time of manufacture but no such assurance is given with respect
to local codes and ordinances because they vary greatly.
The term "breaker" includes all equipment mounted on the circuit breaker foundation.

NOTE
These instructions do not purport to cover all details or variations in equipment or to
provide for every possible contingency to be met in connection with installation,
operation or maintenance. Should further information be desired or should a
particular problem arise which is not covered sufficiently for the purchaser's purposes,
the matter should be referred to HITACHI HVB, Inc.

Each user is responsible for instructing all personnel associated with his equipment on all
safety precautions that must be observed.
The following are recommendations to be considered in a user's safety program. These
recommendations are not intended to supplement the user's responsibility for devising a
complete safety program and shall not be considered as such. They are suggestions to cover
the more important aspects of personnel safety related to circuit breakers. HITACHI HVB, Inc.
neither condones nor assumes any responsibility for user practices that deviate from these
recommendations.

1.2 GENERAL SAFETY

All personnel associated with installation, operation and maintenance of power circuit
breakers should be thoroughly instructed and supervised regarding power equipment in
general and also the particular model of equipment with which they are working. Instruction
books and service advisories should be closely studied and followed.
Maintenance programs must be well planned and carried out consistent with both customer
experience and manufacturer's recommendations, including service advisories and
instruction books. Good maintenance is essential to breaker reliability and safety.
Local environment and breaker application must be considered in such programs, including
such variables as ambient temperatures, actual continuous current, number of operations,
type of interrupting duty, and any unusual local conditions, such as corrosive atmosphere or
major insect problems.

1.3 SPECIFIC SAFETY

 DO NOT work on an energized circuit breaker. If work has to be performed on the
breaker, take it out of service, open the disconnect switches at each side of the
breaker, then close the breaker and ground each phase.

1-6

Chapter 1. Safety

 DO NOT work on any part of the de-energized breaker until all control and heater
power has been disconnected.

 DO NOT disassemble any portion of the gas system of any circuit breaker until system
pressure has been reduced to zero psig by opening the appropriate drain valves. When
the gas pressure has been reduced to zero, cautiously remove covers, tubes, fittings,
etc.

 If SF6 is to be added to a pressurized system, measures should be taken to protect
personnel against sudden gas release. Upon completion of adding gas to the breaker,
the fill valve should be closed. The pressure should then be relieved between the
source and the fill valve prior to removal of transfer tool/filter drier.

 Particular care must be exercised to keep personnel clear of all spring-charged
mechanisms. Only skilled and knowledgeable personnel capable of releasing each
spring load in a controlled manner must service the breaker. Information on
construction of such mechanisms is provided in this instruction manual.

NOTICE
This breaker is spring opened and spring closed.
Always ensure that ALL springs are discharged before working on the breaker.

 The gas breaker will hold line-to-ground voltage under positive SF6 pressure on an
energized transmission line where no voltage disturbances are present. Under these
conditions, the breaker should be de-energized by back-up protection breakers and
isolated and removed from the system as a safety precaution.

 If there is any evidence of deterioration of breaker dielectric capability, the breaker
should be de-energized by back-up protection breakers and isolated from the systems
by disconnect switches.

 Operational tests and checks should be made on a breaker after maintenance and
prior to returning to service to ensure that it is capable of operating properly. The
extent of such tests and checks should be consistent with the level of maintenance
performed.

1.4 SULFUR-HEXAFLUORIDE (SF6) GAS

SULFUR-HEXAFLUORIDE (SF6) gas in its natural state is a colorless, odorless, and tasteless gas
with an extremely low order of toxicity. It is chemically and physiologically inert and non-
flammable.

The SF6 gas is approximately 5.5 times heavier than air, and it will displace oxygen. Because
of this, care should be taken when working with SF6 in an enclosed environment. Since it is
colorless and odorless, care should be exercised when handling the gas to provide good
ventilation. SF6 gas escaping into a closed room or pit will float at the lower levels and can
cause a possible oxygen shortage.

The SF6 gas, when exposed to electrical arcing, may form toxic decomposition products. These
may be evident as an unpleasant odor and a small amount of very fine powdery material
found in the tank.

1-7

Chapter 1. Safety

Before an SF6 tank is entered for maintenance, the gas should be evacuated. The tank should
then be cleaned thoroughly with equipment capable of removing very fine dust particles and
then flushed with dry air to provide oxygen to the normal level.
When entering the tank, a respirator mask should be worn. Powder or dust found in the tank
should be removed while wearing gloves. Hands, face, etc. should be carefully washed if they have
been exposed to the powder.

1.5 SERVICE SAFETY

The information provided in this section is designed to give highlights of the information
provided in this chapter. There are three simple and basic rules that will provide safety for
anyone working on this type circuit breaker.

 Disconnect AC and DC power supplies at the circuit breaker.
 With the AC & DC removed from the circuit breaker no powered operation can be

done either locally or remotely. This would prevent accidental operation of the
breaker due to, someone pressing the local trip/close push buttons (optional) or
remotely operating the breaker from the control system.
 Turn the SF6 test valve to the test position.
 With these valves in the test position the circuit breaker control circuits will be opened.
The breaker would, in effect, be in a lockout status due to loss of gas pressure. This
also precludes the possibility of someone restoring the AC & DC power and then
operating the circuit breaker.

NOTE

Make sure the all springs are discharged.

1-8

Chapter 2. General Information

Chapter 2 GENERAL INFORMATION

2.1 DESCRIPTION OF BREAKER

The HVB 123/145kV/40kA (Figure 2.1) is a high performance dead tank gas circuit breaker.
The breaker ratings are stated on the breaker nameplate. This breaker is a three-phase device
rated to interrupt AC power systems. There is one interrupter assembly per phase, containing
moving and stationary contacts, provided with a single break per phase.

The mechanism is of the stored energy type and is operated by an opening and two closing
springs. An AC/DC motor charges the closing springs. The closing springs are used to close
the breaker and at the same time to charge the opening spring.

Closing and opening operations are controlled electrically by the control switches on the
breaker or by remote relaying. Mechanical handles are provided to manually close and open
the breaker.

Electrical insulation is provided by SF6 gas charged to 75 psig at 20 C (68 F). The cast
aluminum pressure vessels and both entrance bushings are filled with SF6 gas. A gauge
monitors the gas pressure and a temperature compensated pressure switch. Due to the
insulation being provided by the gas, the breaker should not be operated below the lock out
pressure of 64 psig. The pressure switch and control system provide the lockout.

Bushing current transformers (BCT) are usually provided to monitor electrical current passing
through the breaker. The BCT’s are mounted below the entrance bushings inside their own
cover.

There is a control cabinet mounted to the frame and below the tanks. This cabinet contains
the operating mechanism, interphase linkage, control system and the customer connections.
This cabinet is heated to keep moisture from damaging the various devices.

Figure 2.1 HS 123/145 kV 40 kA Gas Circuit Breaker

2-1

Chapter 2. General Information

2.1.1 INTERRUPTER
Figure 2.2 shows the interrupter assembly. The single puffer-type interrupter is installed in a
grounded tank filled with SF6 gas at a reference pressure of 75 psig at 20 C (68 F).

Number Description Number Description
1 Stationary Insulator 12 Moving Arc Contact
2 Bolt 13 Shield
3 Stationary Conductor 14 Puffer Shaft
15 Seal
4,23 Main Contact 16 Seal
5 Main Moving Contact 17 Puffer Piston
6 Arc Contact Support 18 Shield
7 Outer Cylinder 19 Moving Side Conductor
8 Stationary Arc Contact 20 Insulation Rod
9 Arc Contact Support 21 Interrupter Support
10 Nozzle Insulator
11 Cover 22 Support Plate

Figure 2.2 HS 123/145 kV 40 kA Interrupter

2-2

Chapter 2. General Information
2.1.2 PORCELAIN INSULATOR/CONDUCTOR/GAS TANK ASSEMBLY
Figure 2.3 shows the porcelain insulator / conductor assembly installed on each end of the
interrupter tank.

Figure 2.3 Porcelain / Conductor assembly installed on Gas Tank
2.1.3 MECHANISM SPRING-SPRING
The circuit breaker mechanism (Figures 2.4, 2.5) is made up of several assemblies including
the charging system, closing spring, tripping linkage and auxiliary switches.

2-3

Chapter 2. General Information

Motor Limit Switch

Closing Spring Stage
Indicator

Closing Coil

Manual Closing Push Button Closing Coil
Trip Coil

2-4

Chapter 2. General Information

Spring Enclosure
(Close)

Spring Enclosure
(Open)

Figure 2.4 Mechanism side view (Breaker Open Discharged / Spring Charged)

Spring Enclosure (Close) Spring Enclosure (Close)

Spring Enclosure (Open) Shock Absorber

Figure 2.5 Mechanism back view Access port for contact
2.1.3.1 Charging System and Closing Spring travel and slow manual
operation.

The gear motor drives the charging mechanism that compresses the closing springs. The gear
motor turns the gear train that rotates the charging gear. There are two pawls on the charging
gear that turn the charging camshaft. There is a position switch that detects the position of
the charging camshaft and controls the power to the motor. There are two drums on the
camshaft that are attached to links that pull the closing springs to the charged position. The
camshafts and drums compress the closing springs in 180 of rotation. The motor switch also
performs the added function of not allowing the closing coil to operate until the motor has

2-5

Chapter 2. General Information
finished the charge cycle. The interrupter contacts do not move during this operation. This
cycle takes less than 15 seconds.
2.1.3.2 Closing Operation
To close the breaker, electric signal is applied to the closing coil. The coil trips the closing
latch releasing the closing spring to drive the breaker contacts closed through a cam. To close
the breaker, the spring pulls the closing links causing the cam to compress the opening spring
and close the interrupter contacts. Immediately upon the discharge of the closing spring the
closing spring position switch detects that the spring has discharged then the motor is
activated and starts the charging cycle.
2.1.3.3 Tripping Operation
To trip the breaker, electric signal is applied to the trip coil. This coil trips the latch that is
holding the breaker closed. This releases the opening spring that drives the contacts open
with the dashpot controlling the shape of the stroke curve.

Electric Motor

2-6

Chapter 2. General Information

Main Mechanism Gear

Figure 2.6 Spring Operation
WARNING

The breaker must never be operated in a low gas situation, below the 64 psig @
20C lockout pressure. This applies to both manual and electrical operation. The
control system defeats electrical operation, there is no such safety on the
mechanical trip and close devices. There are two reasons for not operating below
this value.
1. The breaker has inadequate electrical insulating and arcing extinguishing

properties below the lockout pressure.
2. The mechanism relies on the gas pressure for damping of its motion.
Operating below the lock out will result in mechanical damage to the breaker and
can cause catastrophic damage to the breaker resulting in injury up to and including
loss of life to personnel near the GCB.
(This note does not refer to slow opening and closing using the manual operating
device on a de-energized breaker.)

2.1.4 INTERPHASE LINKAGE
The interphase linkage connects the mechanism to the three interrupters. This linkage is
made up of a series of collinear shafts in the crank box. The mechanism controls the position
of the interphase linkage through the main crank therefore controlling the interrupter
position.
In the closing action the mechanism pushes on the main crank closing the interrupter contacts.
In the opening action the mechanism pulls on the main crank opening the interrupter contacts.
The gas is sealed by rotating and stationary O-rings.
The Interphase Linkage can be disconnected for each pole for maintenance.

2-7

Chapter 2. General Information

Crank Box

Crank Box Main Rod

2.2 GENERAL CONTROL INFORMATION

2.2.1 INITIAL BREAKER WIRING
2.2.1.1 Control/Mechanism Cabinet
The Control/Mechanism Cabinet will be referred to throughout this manual as the Control
Cabinet, although it contains both the control system and the mechanism. Bring the
customer’s power leads directly into the control cabinet through the removable panel in the
floor of the right side. Attach the leads to the appropriate terminal boards, per the wiring
diagram. The trip coils, close coils, and auxiliary switches located on the mechanism are wired
into the circuit as needed or terminated at a terminal block points.

2.2.1.2 Control Circuits
The control circuits of the breaker consist of the components necessary to energize the trip
and close coils on the mechanism, sense the CLOSE / OPEN positions of the breaker, and
prevent breaker operation if unsafe or unsatisfactory conditions exist.
The close or trip signals are normally input from the customer’s power control circuit, but may
be input by a local push button or trip handle (optional) in the control cabinet. The trip
handles should be for testing only.

2.2.1.3 Closing Operation
When the breaker is to be closed, a signal is impressed on the close circuit. Assuming the
breaker is open in normal operational condition, the normal sequence of events is as follows:

1. The closing coil is energized.
2. The closing coil operates releasing the mechanical latches, allowing the closing springs

to drive the interrupters to the closed position. The closing action also charges the
opening spring.

2-8

Chapter 2. General Information

3. The auxiliary switch operates.
a) Opening all the 52b contacts.
b) Close coil current is interrupted by one or more 52b contacts.
c) Closing all 52a contacts.

4. The 52Y relay contact is connected in series to normally open contacts. This insures
no additional close signals can be applied until this operation sequence is complete.

5. When the close signal is removed, the 52Y relay will be de-energized and the breaker
will remain in the closed position.

6. Close operation is blocked while motor is running to charge the closing springs.
7. Close operation is also blocked when SF6 gas pressure is below certain level.

2.2.1.4 Opening Operation
When the breaker is to be opened, a signal is impressed on either the trip #1 or trip #2 circuit.
Assuming the breaker is closed and in normal operational condition, the normal sequence of
events is as follows:

1. The opening coil is energized.
2. The opening coil operates releasing the mechanical latches, allowing the opening

spring to drive the interrupters to the opened position.
3. The Auxiliary Switch Operates

a) Opening all the 52a contacts. Open coil current is interrupted by one or more 52a
contacts.

b) Closing all 52b contacts.
c) Open operation is blocked when SF6 gas pressure is below certain level.

2.2.1.5 Additional Control Features
Anti-Pump (52Y)
The anti-pump system allows the closing signal to energize the closing coil only one time for
each application of a close signal. This is accomplished by the 52Y relay that opens the close
circuit after the breaker closes and keeps it open until the close signal is removed. On a trip-
free operation the breaker will close then open and will remain open until the original close
signal is removed.
An additional note of interest is that the spring charge control system also blocks the close
function until the motor has finished. Therefore until the motor is finished the anti-pump
relay is not the sole device that opens the close circuit.

2-9

Chapter 2. General Information

402 423 406 415
422 403 410
421
412 425

401

413

420 414
419

424

404
418 411 408 407 409 416 417 405

2-10

Chapter 2. General Information

Prod Product Name Prod Product Name Prod Product Name
uct uct Reducing gear uct Opening lever
No. Closing electromagnetic No. No.
401 solenoid
Tripping electromagnetic 411 421
402 solenoid
Main lever 412 Motor control cam 422 Opening lever
403 Cam
404 Closing sprig 413 Closing link 423 Opening trigger lever
405 Opening spring 414 Closing spring bearing 424 Closing latch roller
406 Main shaft 415 Opening spring bearing 425 Opening latch roller
407 416 Oil dash pot connecting link 426 Motor
417 Oil dash pot connecting 427 Interrupter

408 Cam shaft hinge 428
409 Oil dash pot connecting lever 418 Cam roller 429
410 Oil dash pot 419 Closing lever 430
420 Closing trigger lever

Figure 2.3 Operation of Operating Equipment

2-11

Chapter 2. General Information

2.3 BREAKER OPERATION

The operation of the circuit breaker is covered in the following paragraphs.
2.3.1 MECHANISM
This circuit breaker has a spring-spring mechanism to operate the interrupters.
2.3.2 ARC INTERRUPTION PRINCIPLE
The basic puffer breaker interrupter is shown in Figure 2.6, with an identical unit being used
in each SF6 gas tank. The following sequences describe the Principle of Arc interruption:
Once the trip signal command is issued the insulated operating rod with the puffer cylinder
will be pulled rapidly to the right as the mechanism operates to the open position.
The rapid movement of the cylinder will compress the SF6. The gas is prevented from escaping
the cylinder by the puffer piston and PTFE nozzle.
The cylinder will continue to move causing increasing gas pressure. The main current path will
remain between the arcing contacts after the main contacts are separated.
Further movement of the cylinder will part the contacts and the arc will be established
between the arcing contacts (inside of insulating nozzle).
The blast releasing exhaust ports, at the nozzle and at the other end of the hollow driving
shaft, direct the gas pressure to the established arc.
The axial nature of the gas blast is effective in stretching and cooling the arc. Total blast time
varies from 16 to 25 milliseconds, depending on current being interrupted.
Full interrupting capacity is provided with gas densities corresponding to gas pressures from
64 to 75 psig at 20 C.

2-12

Chapter 2. General Information

Figure 2.7 Principle of Arc Interruption

2-13

Chapter 3 - Installation

Chapter 3 INSTALLATION

3.1 PACKING SHIPPING AND RECEIVING

Packaging has been planned to support the field erection sequence and provide easy
identification of the components.
The breaker is shipped from the factory on one truck ready for installation. All parts necessary
to assemble the breaker are included as well as additional items required under the purchase
contract.
The shipment is broken down into the following main items (crucial to the proper assembly
and installation of the circuit breaker):

 GCB Assembly
 Parts Box
Upon arrival, the entire shipment should be checked for damages or shortages. Shipping
papers, including a packing list along with an instruction manual and a full set of prints, will
be in a plastic envelope in the pocket inside of cabinet door. Additionally, a second copy of
this packing list can be found in the parts box normally shipped with the circuit breaker.

NOTE
It is especially important that any damage incurred during shipping, be reported as
soon as possible to HITACHI HVB, Inc. to assure early delivery of replacement parts.

3.2 TOOLS AND TESTING EQUIPMENT

Items actually sent with every shipment may vary in quantity and appearance according to
the requirements of the particular unit or customers contract.

3.2.1 TOOLS
Most of the work on this circuit breaker can be accomplished using standard tools. The
hardware on the circuit breaker are normally metric. The gas piping system is US standard.

1. Special tools are normally required in the purchase contract and shipped with the
circuit breaker. One set of tools is supplied with every five (5) circuit breakers or for
every different substation on an order. Your purchase contract can, of course, affect
the amount of tools shipped. The following is a list of tools normally shipped.
a. Grease - Gleitmo 805 K
b. Grease - Hitalube 280
c. SF6 Gas Transfer Tool
d. Maintenance Operating Screw Assembly, this screw requires a 1 1/8 wrench to
operate (wrench is not supplied).
e. Adapter - GCB Tank to SF6 bottle

3-1

Chapter 3 - Installation

f. Manual charging closing springs device. This device is used to charge the
closing springs when the motor power is temporarily lost (emergency case).
The device is permanently installed on mechanism plate (above the motor) as
shown in Figure 3.1.

Figure 3.1. Manual Charging of Closing Springs Device
Instruction how to operate it:
To charge the closing springs, use a 19 mm socket and a RATCHET WRENCH
(THE MOTOR POWER MUST BE DISCONNECTED) and crank clockwise (viewing
from left) until is heard a click. At this moment STOP cranking, the closing
springs are charged.
g. Do not crank after the charging cycle is completed.

2. The following list is intended to include the common METRIC hand tools required to
maintain this circuit breaker. These tools are not supplied with a circuit breaker except
as a special order. Metric tools are not considered “Special Tools” as they are required
for more equipment than this circuit breaker.
a. Sockets
i. 1/2 inch drive - sizes M10, M13, M17, M19, M30
ii. 3/8 inch drive - sizes M6 through M26
b. Wrenches
i. Combination - sizes M10, M13, M17, M19
c. Scale
i. 150 millimeters - approximately 6 inch
ii. 1000 Millimeters - approximately 3 feet
d. Allen Wrenches

3-2

Chapter 3 - Installation

i. Sizes up to M10

3.2.2 TESTING EQUIPMENT
Certain equipment should be available for installation and future maintenance testing of the
circuit breaker.

1. Gas handling equipment with a vacuum pump
2. Vacuum gauge capable of reading 1mm of mercury or 1000 microns
3. SF6 Leak Detector
4. Electrolytic Hygrometer - (SF6 Moisture Analyzer)
5. Digital Micro-ohmmeter
6. Megger - 1000 Volt
7. Leak - Tec or equal for gas leak testing
8. Ductor - 100 Amp
9. Motion Analyzer
10. Thermometer
11. Calculator
12. Indicating flashlight with leads

3.3 STORAGE

3.3.1 BREAKER ASSEMBLY
1. Check to be sure each pole has a slight positive pressure by opening the fill valve. If the
breaker shows zero pressure pull vacuum before filling with SF6, see Chapter 4 for method.
For storage set the gas pressure to 5 to 15 psig the low of 5 is to ensure that the interrupters
and tank internals stay clean and dry. Storage pressures above 15 psig are not necessary
and constitute a safety hazard in case the bushings are damaged in storage. Check at
monthly intervals for positive pressure.
2. Connect all heaters to a proper voltage source. Power leads should enter the control
cabinet through the floor by removing a bolt in the floor. Connection should be made at
the heater fuse to supply heater power. DO NOT LEAVE DOORS PARTIALLY OPEN.

3-3

Chapter 3 - Installation

SP6 Pressure Gauge

Figure 3.2. Assembly
3.3.2 ALL PARTS BOXES
These parts should be kept dry at all times and stored inside a building, if possible. If unable
to store inside, keep off the ground and out of standing water. Cover with canvas or heavy
plastic tarpaulin.

3.4 ASSEMBLY INFORMATION

3.4.1 PRELIMINARY INFORMATION
The three poles of the 123/145kV gas breaker are identical on the standard breaker.
These instructions are supplemented by a set of drawings supplied with the breaker. The
types of drawings furnished include the outline, assembly, electrical elementary, electrical
device and ratings list. These drawings, along with any others that the customer may have
requested, are placed with the breaker instruction book, and stored in a special pocket on the
electrical control house door.
The breaker will be located on a reasonably level foundation and properly shimmed and
secured with anchor bolts. The foundation is to provide uniform support to the frame and
SF6 gas tanks and to not add any stress. Space must be provided for opening the control
house doors and making the necessary control connections.
Space should be allowed at the end of each pole to allow for possible maintenance of the
internal parts of the breaker. Should flood conditions exist, the foundation must be
sufficiently high to assure the control house is above the high water level.
All standard safety practices, codes and ordinances should be followed during erection and
operation of the breaker.

3-4

Chapter 3 - Installation

Prior to any work being done on the subject breaker, the section of this manual on safety
should be reviewed and understood thoroughly.

CAUTION
When working on the gas system open fill valves even though the gauge indicates
zero pressure. To ensure that you do not open a vessel that is under pressure!
DO NOT open interrupter tank when there is a chance of water, dust, or other
contaminants entering the vessel. Internal cleanliness is essential to the successful
operation of the circuit breaker. The tanks are charged to a positive pressure with
SF6 gas when delivered. This pressure should be kept in mind when beginning
installation

SAFETY
Each user, contractor, or installer is responsible for instructing all personnel
associated with this equipment on all safety precautions that must be observed.
Read the SAFETY SECTION in this Instruction Manual.

3.4.2 GENERAL ASSEMBLY PROCEDURES
1. The foundation should be of sufficient strength stability to prevent any stress in the SF6
tank due to ground movement. Foundation to be level within 0.25 inch within support
areas. For bolt pattern and loads see breaker outline drawing. Sling the breaker assembly
using the four lifting plates. Use equal length cables that are 8 feet or longer.
2. Bolt the breaker in place using heavy washer attached to the two ground pads on the
support beams. If necessary, shim between support plates and foundation to insure a
direct transmission of loads to the foundation and prevent stressing the SF6 tanks.
3. Install all ground leads to the frame ground pads as show on customer drawing. Connect
the ground strap at the bottom of the control cabinet to the ground grid.
4. Each pole assembly is factory charged to approximately 5 psig with SF6. Therefore it is not
necessary to pull vacuum on the breaker, simply fill with dry SF6. Approximately 47 lbs. of
gas will fill the GCB. See Chapter 4 for SF6 handling.

3.5 INSTALLATION TESTING

3.5.1 GENERAL
Please see the next section for the Installation Check-List. Timing tests are optional and are
not required. Be sure to follow all manufacturer’s instructions when using the specialized
equipment required in this section.

1. Fill out owner and circuit breaker information on the first page of the Installation
Check-List.

2. Perform the inspections on the first page.
3. SF6 Gas System

a. Record ambient air temperature

3-5

Chapter 3 - Installation

b. Record the gauge pressure. The correction factor is calculated from the
instruction books Temperature vs. Gas Pressure chart, see chapter 4.

c. Switch checks. Record the gauge readings for both ON (decreasing pressure)
and RESET (increasing pressure). Use the correction factor to normalize the
pressure to a room temp value. Confirm that the corrected values are within
the tolerances in the chart.

d. Leak check the gas system
e. Moisture analysis is recommended. When using gas provided by HVB the gas

is guaranteed by the supplier to have a moisture level below 150 ppm,
therefore testing moisture with HVB gas is optional.

3.5.2 MECHANICAL TESTS
3.5.2.1 External stroke and wipe measurement, (Figure 3.4)

1. Connect an indicating light, flashlight with leads, to the three poles of the breaker to
determine when the contacts close.

2. Remove the cover on the back of the opening spring and insert the manual charge
screw into the threads. Tighten the screw until it is hand tight. Record the length of
threads (A) that is sticking outside the spring tube. Using a wrench, tighten the screw
into the spring tube, (this will cause the contacts to move) until the first light lights.
Write that value (B) in the column “Contact” for the appropriate pole. Continue for
each of the three lights.

3. Continue to tight the screw. Watch for the trip latch to set. STOP operating the manual
screw when the latch sets. Back off the manual screw to allow the latch to carry the
spring load. You will feel the screw become easier to turn as the latch takes the load.
The breaker is now in the closed position. Before making the final measurement (C)
be sure that the screw is hand tight against the open spring. Calculate the External
Stroke (A-C) and Wipes (B-C).

4. Open the breaker by tightening the screw against the spring load again. Press and hold
the red open button to clear the trip latch, then open the breaker by unscrewing the
manual operating screw. After one turn the latch will have cleared and the open
button can be released.

5. Remove screw and install back the open spring cover.
6. Calculate the Delta (Phase to Phase) by calculating the difference between the max

and min values of wipe.

3-6

Chapter 3 - Installation

Figure 3.3. Lathing Mechanism (Open Spring)

3.5.2.2 Circuit breaker operational test
This test can be performed with or without motion analyzing equipment. Performing a motion
test with analyzing equipment is optional. If the transducer is attached to the same location
as the external stroke was measured the transfer function is: 97 mm external stroke / 154
mm internal = .63

1. Test for the close, C, and open, O, function by pressing the open and close electrical
buttons. If equipped for dual trip, test both.

2. To test C-O & Anti Pump the breaker must be in the open position. Press both open
and close buttons simultaneously. The breaker should close then immediately open
with no delay then lockout the close function as long as the close button is held in. To
properly test hold the close button until after the motor has stopped charging.

3. For the O-C test the breaker must be in the closed position. Press and release the open
button. The breaker should open. Then press the close button and the breaker should
close.

4. SF6 Lockout Function. Before performing this test, check the schematic to see if the
control circuit is designed to simply lockout the operation of the breaker or open then
lockout. To perform this test, turn the test valve to the test position. Slowly open the
purge valve until the gauge reads below 64 psi and the SF6 density monitor has
switched for lockout. Then press the open and close buttons. If the breaker has a
simple lockout the mechanism should not operate. If the breaker has an open then
lockout function, the breaker should open on low pressure then pressing the buttons
should not operate the mechanism.

3-7

Chapter 3 - Installation

Figure 3.4. External Stroke and Wipe Measurement
3.5.3 ELECTRICAL TESTS
3.5.3.1 Contact resistance, (Ductor test)
It measures the integrity of the contact joints in the current path. This measurement can be
made on the breaker before or after gas is in the tanks. The individual poles should be
checked using a 100 A Ductor with 100 A flowing. A complete pole unit measured from
bushing terminal to bushing terminal should measure 120 micro ohms or less with the breaker
fully closed. Ductor readings taken after gas is in place should have no noticeable change.

NOTE
If readings are high, check the connection at the top of the bushing to ensure that
the connection is not adding any additional resistance.

3-8

Chapter 3 - Installation

3.5.3.2 Insulation resistance, (1000 V Megger Test)

It measures the integrity of the GCB insulation. For this measurement the breaker should have
SF6 gas in the tanks to a pressure at or above the lockout pressure. The purpose for requiring
gas is to insure a moisture free environment inside of tanks. Note that most of the leakage
current will occur on the outside of the bushing insulator and not inside the gas tank.

1. Test with the breaker in closed position. Put the positive lead on one of the bushing
terminals and the negative on the grounded gas tank. Value must exceed 1000 M.

2. Test with the breaker in open position. Value must exceed 2000M. There are two
situations to test:

a. One is from terminal to terminal on each pole.

b. The other is from terminal to ground on each bushing.

3. If measured value is less than noted value, check as follows before concluding there is
an internal problem:

a. Resistance measurements in the  range with 1000 V Megger, can be
sensitive to lead position similar to capacitance measuring. Shielded leads
should be used for best results.

b. Outside of porcelain should be cleaned and a three-turn guard placed between
second and third petticoat of each bushing and connected to the guard
terminal of Megger.

c. Earth lead is connected to good ground on tank. Lead position is not important.

d. The connecting lead from the top of the bushing should be tied to keep lead
from touching outside of bushing or any metal of breaker. Similar to 10 kV
capacitance measuring.

e. Remove lead from bushing not connected to Megger, or keep tied to keep free
of all parts of this segment and must not touch ground.

f. Connection to line post of Megger to be as short as possible to connect the
test lead.

g. Tie clear of all metal parts or ground.

h. Do not touch earth, lead or Megger case.

i. Do not allow to sag and touch ground.

j. Personnel not to hold or touch leads.

k. Leads twisted together, laid on the ground or touching other possible leakage
paths can make an insulator of 8000  or higher appear to be 500-1000 

l. Let the breaker gas environment reach equilibrium for one week. This will
allow the desiccant to remove all of the moisture and allow the environment
to reach steady state conditions.

m. Insulators may have a surface layer of moisture that should disappear within
one week when gas with a dryness less than 150 ppm has been added and new
desiccant is in place.

3-9

Chapter 3 - Installation
NOTE
Power factor tests are not required on SF6 bushings, these tests provide no useful
information on SF6 filled equipment and are not recommended by HITACHI HVB,
Inc. for our equipment.

3-10

Chapter 3 - Installation

3.6 INSTALLATION & ASSEMBLY CHECK-LIST

HVB AE Power Systems, Inc.
145k VHS-40kA SF₆ gas Circuit Breaker Installation & Assembly Check-List

Section 1: Customer Information: Customer Rep.
Position
Customer Phone
Sub-Station
HVB FSE
Site Address Service Date

City, State, Zip

Section 2: GCB Data: Ratings kV kA A

Serial Number Control Voltage VDC
Shop Order No.
Mfg. Date Motor Control Voltage VAC

Wiring Diagram Normal SF6 Pressure Psig @
___⁰ F

Trip Coil No. Close Coil No.
Operation Counter
Initial Final

Section 3: Installation:

3.1 Receiving

Check for Missing and Damaged Parts. Refer to HVB packing list.

Item Material Description Checked Remarks
No. Yes No Received “YELLOW” Warning
Sheet – Check: Yes __ No __
1 GCB – All Phases

2 Bushing Assemblies (If shipped separately)

3 Control Cabinets

4 Mechanism Cabinets
5 Mechanism
6 Corona Rings (If applicable)
7 GCB Frames & Hardware
8 Accessories Box (Inventory all items)

Form No: GCB145HS Rev No: 3 Form Approved By: Baiju Gajjar
Date: January 21, 2006
Previous Revision is Obsolete Revision Date: January 4, 2007

F:\Field Service\Field Service Forms\GCB145HS-40kA_Rev3

3.2 Installing Breaker

Refer to HVB frame assembly drawing or an outline drawing.

Description Checked Remarks

3-11

Chapter 3 - Installation

Item Yes No
No.
Assemble GCB frame
1 Install GCB on the frame
2 Secure GCB to frame
3 Check GCB level
4 Set GCB control cabinet
5 Foundation bolts secured
(all legs & control cabinet legs)
6 Ground leads secured to ground pads (all pads)

7

3.3 Installing Bushing (Not applicable if shipped with bushings installed)

Refer to 145HS Instruction Book

Item Description Checked Remarks
No. Yes No

1 De-pressurized GCB (shipped with positive N₂ pressure)

2 De-pressurized bushing from bushing shipping cover

3 Inspect and clean center conductor

4 Inspect and clean throat shield

5 Inspect and clean tank nozzle flange

6 Inspect , clean, and grease bushing gasket

7 Install throat shield (If applicable)

8 Install bushing

9 Install corona rings (If applicable)

10 Torque all bolts Torque wrench ID:___
Calibration Date:___

3.4 Gas Handling

Important! If bushings are field installed, replace desiccant and pull vacuum down to 1-torr and hold for 2 hrs.

Pole 3 Pole 2 Pole 3 Ambient
Temp.
Device ID Correction Gauge Temp. Gauge Temp. Gauge Temp. (⁰ F)
Factor Press. Comp. Press. Comp. Press. Comp.
Press. Press. Press.

GCB +/-
Gauge +/-

Calibrated
Gauge

Important! (Applicable only bushings are field installed)

Replace the desiccant in each pole with two of the new bags provided in the parts shipment, before the final sealing
of the inspection port.

Form No: GCB145HS Rev No: 3 Form Approved By: Baiju Gajjar
Date: January 21, 2006
Previous Revision is Obsolete Revision Date: January 4, 2007

F:\Field Service\Field Service Forms\GCB145HS-40kA_Rev3

Section 4: Start-Up & Checks

4.1 Control Wiring Checks

3-12

Chapter 3 - Installation

Item Description Checked Remarks
No. Yes No
Supply Voltage (125VDC)
1 Motor Control Voltage (120 VAC OR 240 VAC OR 208
VAC)
2 Supply Voltage for heater, receptacles and lights.
All device setting
3 CT Connection
4 Inter-phase wiring
5
6

4.2 SF6 GAS Leak Checks (Red Line all compression fittings)

Item Description Checked Remarks
No. Yes No
Pressure relief valve
1 Fill valve and fitting (Check for factory mark for tightness. Check___, if loose)
2 Lines and connection fittings
3 Thru-hull fittings
4 Control cabinet lines
5 Stationary box end plates
6 Crank box end plates
7 Bushings
8 Pressure gauge assembly
9

4.3 SF6 Pressure Switch Checks

Phase Switch Purpose Normal Initial Final
Common Alarm On Reset On Reset On Reset
Alarm 1 Block
(63 GDA-1) Block 67±2 69±2
Lockout 1
(63 GDC-1) 64±2 68±2
Lockout 2
(63 GDC-2) 64±2 68±2
Annunciator 1 64±2 68±2

GAS MOISTURE READINGS

Phase Measurement Unit Criteria
A
B ppm <150ppm
C
ppm <150ppm
Instrument Mfg.:
ppm <150ppm

Instrument ID: Calibration Date:

Form No: GCB145HS Rev No: 3 Form Approved By: Baiju Gajjar
Date: January 21, 2006
Previous Revision is Obsolete Revision Date: January 4, 2007

F:\Field Service\Field Service Forms\GCB145HS-40kA_Rev3

Section 5: Breaker Testing

5.1 Mechanical Tests

3-13

Chapter 3 - Installation

Open (Full Stroke) Specification Pole 1 Pole 2 Pole 3
97 ± 1.5 mm
Contact (Increasing)
Wipe --
20.5 ± 1.5 mm
Delta (Phase to Phase)
Max 2 mm

To determine wipe, subtract Contact Touch from Close. To determine delta, find the difference between min. and
max. Value of Contact.

(Full stroke internal is 154 mm external is 97mm =0.63 conversion)

5.2 Insulation and Contact Resistance Measurements

Test Limits CB Position Pole 1 Pole 2 Pole 3

Insulation > 1000 MΩ Closed Calibration Date:
Calibration Date:
Contact Resistance > 2000 MΩ Open
Megger Instrument Mfg.:
Ductor Instrument Mfg.: > 120 µΩ Close

Instrument ID:

Instrument ID:

5.3 Circuit Breaker Operational & Functional Tests

Test Pass Comments
Yes No
Relay Check - Loss of VDC
Anti-Pump 52Y Test Max. ______ Operations before Lockout
Motor Over-Run*
O
C
O
O-C
C-O
Lock-Out Function

* Follow guidelines provided on the “YELLOW” warning sheet located inside the control cabinet. Failure to do so
will result in equipment mechanism failure and warranty will be null.

Form No: GCB145HS Rev No: 3 Form Approved By: Baiju Gajjar
Date: January 21, 2006
Previous Revision is Obsolete Revision Date: January 4, 2007

F:\Field Service\Field Service Forms\GCB145HS-40kA_Rev3

5.4 Timing Test

Item Control Voltage Criteria Comments
(VDC) Check Only
Closing (Close) Time (ms) Delta (ms)
Opening (Open)
Close-Open (CO) 125 ≤ 150 ≤ 5

Distance 125 ≤ 35 ≤ 3

Stroke - External 125 -- --

Wipe - External mm

Timing Set Mfg.: N/A 97 ± 1.5
N/A

N/A 20 ± 1.5
N/A

Instrument ID: Calibration Date:

3-14

Chapter 3 - Installation

Additional Comments

Inspected Date of Customer Name
By: Inspection: & Signature:

Form No: GCB145HS Rev No: 3 Form Approved By: Baiju Gajjar
Date: January 21, 2006
Previous Revision is Obsolete Revision Date: January 4, 2007

F:\Field Service\Field Service Forms\GCB145HS-40kA_Rev3

3-15

Chapter 4 - SF6 Gas System

Chapter 4 SF6 GAS SYSTEM

4.1 GENERAL INFORMATION

For safety considerations, consult Chapter 1 of this instruction manual before proceeding with
these instructions. The SF6 gas system includes monitoring gas pressure, filling the GCB with
gas and the gas sealing O-ring seals.
This chapter covers two gas monitoring systems, which use one of the following systems:

 A - the Qualitrol Temperature Compensated Gas Pressure Gauge as well as the
optional non-temperature compensated monitoring.

 B - the Solon Temperature Compensated Gas Pressure Switch as well as the optional
non-temperature compensated monitoring.

 C – the WIKA Temperature compensated Gas Pressure Switch as well as the optional
non-temperature compensated monitoring.

The craftsperson should always refer to the breaker specific drawings to confirm which gas
monitoring system is installed. Additionally, in a separate section, specific instructions for
non-temperature compensated SF6 monitoring equipment is described. The customer can
choose optional equipment to be used in your monitoring system that is covered in later
sections of this chapter as well.

NOTE
Refer to your circuit breaker drawings to determine which sections of these
instructions are relevant and refer only to those that apply.

NOTE
No maintenance is possible on any pressure/density switches supplied by HVB.
No replacement parts are listed except for replacement of the complete device.

DISCLAMER
This chapter covers the most common gas systems, however due to the customized nature
of the product, there may be differences with regards to customer preference. In which
case, if questions arise due to such differences, it may be advisable to consult HITACHI HVB,
Inc. to attain proper gas filling / system information.

4.2A SF6 TEMPERATURE COMPENSATED PRESSURE GAUGE

This GCB uses a Qualitrol SF6 temperature compensated pressure gauge, (Figure 4.1A). The
temperature compensated pressure gauge automatically adjusts its operating points higher
or lower as a result of ambient temperature changes. There should be a label on gauge to
indicate the part # and contacts settings.

4-1

Chapter 4 - SF6 Gas System
As density changes the dial pointer moves. The switches themselves operate depending on
the physical pointer position and are fixed and stationary. The switch contacts are factory
adjusted for each switch value. As the pointer moves down the scale it contacts each switch
in succession.

NOTE
This device and its internal switches ARE NOT field adjustable. If switches appear
to be out of specs. Contact HVB.

Figure 4.1A Temperature Compensated Pressure Gauge

4-2

Chapter 4 - SF6 Gas System

4.3A FILLING WITH SF6 GAS

NOTE

Read ALL of the instructions below prior to filling the breaker with SF6 gas.

1. The moisture content of the SF6 gas should be 150ppm, by volume, or less. The cylinder
should be checked with a suitable hygrometer before using in the GCB. If the SF6 gas was
supplied with the circuit breaker it is guaranteed to by dry to less than 150 PPM. Leave the
hygrometer on until a reading of 150 PPM or lower has been obtained. If a reading of 150
PPM or lower cannot be reached, dry the hygrometer with dry air or nitrogen until below
100 PPM. Immediately recheck.

2. If moisture analysis is to be done on the GCB, use the fill valve for moisture sampling. If a
reading of 150 PPM or lower is still not obtained wait one week and recheck during the
cool morning hours. Finally, if a reading of 150 PPM is still not obtained, remove the gas
and replace the desiccant in the tank with fresh bags and dry the gas if it’s to be re-used.
Expected normal value should be under 100 PPM within one week.
NOTE
The filter drier should be replaced after having been used with 50 cylinders of gas.
It is suggested a mark be placed on the filter drier to record each cylinder used.
The dryer hose assembly should be capped at both ends when not in use. An SF6
gas cylinder will weigh about 225 pounds filled, with the gas content being
constant at 115 pounds.

CAUTION
Do not remove the end covers of any SF6 piping until just before connection, this
is to keep moisture out of the vessel and piping. Use dry air or nitrogen to purge
the gas lines of moisture or material prior to connection. Keep dust, dirt, moisture,
etc. from entering the lines prior to connection.

3. Put the 3-way test valve (Figure 4.2A) in NORMAL position. Then turn the discharge end of
the valve on the gas cylinder to face the fill valve. Remove the shipping plug from the valve
of the cylinder and the cap on the end of the adapter. Using the adapter with the left-hand
threads, attach the filter-dryer to the valve in the cylinder. The fitting on the hose also has
a sealing plug. Install the adapter on the fill valve. Tighten all connections, and then loosen
the nut on the hose at the fill valve end with the valve closed. Slowly open the valve on the
SF6 cylinder for approximately 30 seconds to purge the gas transfer assembly. Tighten the
nut then close the valve on the cylinder. The connection is now filled with SF6 gas and
ready to fill the breaker tank.

4. No regulator is required with the filter-dryer. An orifice with 0.05-inch diameter is installed
between the filter and the gas bottle of the transfer hose to control the flow rate of the
gas cylinder. Open the valve at the breaker, then the cylinder valve. The filling process can
be detected by sound or condensation on the fittings.

4-3

Chapter 4 - SF6 Gas System

5. Approximately 47 lbs. of gas will fill the GCB from shipping pressure (approx. 5psig) to rated
pressure (75 psig). The gas flow may stop due to chilling.

6. To measure the gas pressure, make sure the valve is in the normal position and allow the
gas pressure to rise while being monitored.

7. During the filling of the breaker, a calibrated gauge need not be used to monitor the phase
pressure. Determine the tank’s body temperature by attaching a thermometer to the
shaded side of the tank. Do not read in less than fifteen minutes after attaching.

8. See breaker nameplate for standard gas system pressure. Fill the GCB till the reading on
the gauge meets the reading on the tank within ± 3psig.

9. Shut off the fill valve on the GCB gas tank and then the SF6 tank cylinder valve. Slowly
loosen the connection at the cylinder to drain the pressure from the filter-dryer and fill
hose.

10. Replace the cap in end of gas transfer tool to keep dirt and air out of the filter - dryer.
Replace the safety cap on the SF6 cylinder and remove the cylinder.

11. Allow the gas pressure to balance for twelve hours and then re-check the pressure. If
additional gas is needed, repeat the steps above.

Figure 4.2A. Valves in the Gas System

4.4A SF6 LEAK RATE AND LEAK DETECTION

The maximum permissible design leakage is one psi per year. The rise and fall of pressure
should be observed for a period of one month to determine the loss due to leakage.
Remember that the pressure switch on the breaker is temperature compensated. When
checking with a regular gage, changes in pressure due to temperature fluctuations must be
taken into consideration. An allowance equal to about 1 1/2 psig for every five degrees C
should be made for variation in temperature.
If leakage is determined in excess of one psig per year, use an SF6 gas leak detector at all
gaskets, bolted and flared joints. If an SF6 instrument is not available, a high viscosity solution,
such as “Leak Tec Formula 277CHV”, can be used. The solution should be cleaned from the
surface using a clean damp cloth completes the leak checking.

4-4

Chapter 4 - SF6 Gas System

4.5A SF6 TEMPERATURE COMPENSATED GAS MONITORING SYSTEM

The temperature compensated gas monitoring system is provided with a three phase
common pressure-monitoring scheme that gangs the pressure of all three phases together to
a single temperature compensated pressure gauge (Figure 4.3A). An optional individual phase
monitoring systems is available and described in later section of this chapter.

Figure 4.3A. Three Phase Common Gas Monitoring System
The typical system is furnished to provide an alarm circuit when the pressure in the
interrupter tank falls below 67 psig at 20°C. Additional contacts can enable the system to
provide a command at 64 psig at 20°C.
The minimum operating pressure for full dielectric strength and interrupting capacity is 64
psig at 20°C. Below this pressure the breaker should be isolated from the system. Operation
of the circuit breaker below this pressure can result in damage due to reduced backpressure
in the puffer cylinder and excessively high operating speeds and a failure to interrupt due to
low dielectric strength caused by insufficient SF6 gas.
SF6 in the gaseous state will show a change in pressure as its temperature is changed. This is
represented by the curve shown in Figure 4.5. The table (Figure 4.4) shows the SF6
Temperature versus Pressure Nameplate that is normally provided on the cabinet door.

4-5

Chapter 4 - SF6 Gas System

4.2B TEMPERATURE COMPENSATED PRESSURE SWITCH

This GCB uses a Solon SF6 temperature compensated pressure switch and a regular pressure
gauge (Figure 4.1B). The temperature compensated pressure switch automatically adjusts its
operating points higher or lower as a result of ambient temperature changes. There should
be a label on each switch to indicate the part # and switch settings.
Temperature compensation is accomplished internally by a Bi-metal disk springs. It is
recommended that the pressure settings not be adjusted in the field. If the switch appears to
be out of tolerance contact HITACHI HVB, Inc. for instructions.

NOTE

Do NOT adjust Pressure Switch. If Switch appear to be out of specs. Contact HVB.

63GDA Figure 4.1B Temperature Compensated Pressure Switch PSI
63GDC 672
OPERATION 692
Operates on Descending Pressure 642
Resets on Ascending Pressure 682
Operates on Descending Pressure
Resets on Ascending Pressure

4-6

Chapter 4 - SF6 Gas System

4.3B FILLING WITH SF6 GAS

NOTE

Read ALL of the instructions below prior to filling the breaker with SF6 gas.

1. The moisture content of the SF6 gas should be 150ppm, by volume, or less. The cylinder
should be checked with a suitable hygrometer before using in the GCB. If the SF6 gas was
supplied with the circuit breaker it is guaranteed to by dry to less than 150 PPM. Leave
the hygrometer on until a reading of 150 PPM or lower has been obtained. If a reading of
150 PPM or lower cannot be reached, dry the hygrometer with dry air or nitrogen until
below 100 PPM. Immediately recheck

2. If moisture analysis is to be done on the GCB, use the fill valve for moisture sampling. If a
reading of 150 PPM or lower is still not obtained wait one week and recheck during the
cool morning hours. Finally, if a reading of 150 PPM is still not obtained, remove the gas
and replace the desiccant in the tank with fresh bags and dry the gas if it’s to be re-used.
Expected normal value should be under 100 PPM within one week.

NOTE
The filter drier should be replaced after having been used with 50 cylinders of gas.
It is suggested a mark be placed on the filter drier to record each cylinder used.
The dryer hose assembly should be capped at both ends when not in use. An SF6
gas cylinder will weigh about 225 pounds filled, with the gas content being
constant at 115 pounds.

CAUTION
Do not remove the end covers of any SF6 piping until just before connection, this
is to keep moisture out of the vessel and piping. Use dry air or nitrogen to purge
the gas lines of moisture or material prior to connection. Keep dust, dirt, moisture,
etc. from entering the lines prior to connection.

3. Put the 3-way test valve (Figure 4.2B) in NORMAL position. Then turn the discharge end
of the valve on the gas cylinder to face the fill valve. Remove the shipping plug from the
valve of the cylinder and the cap on the end of the adapter. Using the adapter with the
left-hand threads, attach the filter-dryer to the valve in the cylinder. The fitting on the
hose also has a sealing plug. Install the adapter on the fill valve. Tighten all connections,
and then loosen the nut on the hose at the fill valve end with the valve closed. Slowly
open the valve on the SF6 cylinder for approximately 30 seconds to purge the gas transfer
assembly. Tighten the nut then close the valve on the cylinder. The connection is now
filled with SF6 gas and ready to fill the breaker tank.

4. No regulator is required with the filter-dryer. An orifice with 0.05-inch diameter is
installed between the filter and the gas bottle of the transfer hose to control the flow
rate of the gas cylinder. Open the valve at the breaker, then the cylinder valve. The filling
process can be detected by sound or condensation on the fittings.

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Chapter 4 - SF6 Gas System

5. Approximately 47 lbs. of gas will fill the GCB from shipping pressure (approx. 5psig) to
rated pressure (75 psig). The gas flow may stop due to chilling.

6. To measure the gas pressure, make sure the valve is in the normal position and allow the
gas pressure to rise while being monitored.

7. During the filling of the breaker, a calibrated gauge need not be used to monitor the
phase pressure. Determine the tank’s body temperature by attaching a thermometer to
the shaded side of the tank. Do not read in less than fifteen minutes after attaching.

8. See breaker nameplate for standard gas system pressure. Fill the GCB till the reading on
the gauge meets the reading on the tank within ± 3psig.

9. Shut off the fill valve on the GCB gas tank and then the SF6 tank cylinder valve. Slowly
loosen the connection at the cylinder to drain the pressure from the filter-dryer and fill
hose.

10. Replace the cap in end of gas transfer tool to keep dirt and air out of the filter - dryer.
Replace the safety cap on the SF6 cylinder and remove the cylinder.

11. Allow the gas pressure to balance for twelve hours and then re-check the pressure. If
additional gas is needed, repeat the steps above.

Figure 4.2B Valves in the Gas System

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Chapter 4 - SF6 Gas System

4.4B SF6 LEAK RATE AND LEAK DETECTION

The maximum permissible design leakage is one psi per year. The rise and fall of pressure
should be observed for a period of one month to determine the loss due to leakage.
Remember that the pressure switch on the breaker is temperature compensated. When
checking with a regular gage, changes in pressure due to temperature fluctuations must be
taken into consideration. An allowance equal to about 1 1/2 psig for every five degrees C
should be made for variation in temperature.
If leakage is determined in excess of one psig per year, use an SF6 gas leak detector at all
gaskets, bolted and flared joints. If an SF6 instrument is not available, a high viscosity solution,
such as “Leak Tec Formula 277CHV”, can be used. The solution should be cleaned from the
surface using a clean damp cloth completes the leak checking.

4.5B SF6 TEMPERATURE COMPENSATED GAS MONITORING SYSTEM

The temperature compensated gas monitoring system is provided with a three phase
common pressure-monitoring scheme that gangs the pressure of all three phases together to
a single temperature compensated pressure switch and a regular pressure gauge (Figure 4.3B).
An optional individual phase monitoring systems is available and described in later section of
this chapter.
The typical system is furnished to provide an alarm circuit when the pressure in the
interrupter tank falls below 67 psig at 20° C. Additional contacts can enable the system to
provide a command at 64 psig at 20°C.
The minimum operating pressure for full dielectric strength and interrupting capacity is 64
psig at 20°C. Below this pressure the breaker should be isolated from the system. Operation
of the circuit breaker below this pressure can result in damage due to reduced backpressure
in the puffer cylinder and excessively high operating speeds and a failure to interrupt due to
low dielectric strength caused by insufficient SF6 gas.
SF6 in the gaseous state will show a change in pressure as its temperature is changed. This is
represented by the curve shown in Figure 4.5. The table (Figure 4.4) shows the SF6
Temperature versus Pressure Nameplate that is normally provided on the cabinet door.

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Chapter 4 - SF6 Gas System

Figure 4.3B Three Phase Common Gas Monitoring System

4.6 TESTING SF6 SYSTEM PRESSURE

A valving arrangement to check the SF6 gas pressure alarm switch has been built into the gas
system and may be used in the following manner:
1. Remove all AC and DC connections to the control cabinet. Failure to do the will cause the

breaker to send low gas alarms and the breaker will lockout when testing the lower
pressure value
2. Turn test valve off, perpendicular to the direction of gas flow. This isolates the SF6
temperature compensated pressure switch from the breaker tank. Very slowly continue
to turn the test valve while watching the pressure gauge. Allow the pressure to drop
gradually. The pressure at which the temperature compensated pressure switch operates
will represent the alarm or command pressure.
3. Return the handle to the initial position, parallel to the gas flow. Failure to do so will leave
the switch isolated from the pressure vessels resulting in a hazardous system with no
protection against low SF6 gas pressure.
4. To ensure accurate testing:

a. Check all pressures after the breaker has been de-energized minimum 6 hours

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Chapter 4 - SF6 Gas System

b. Take the readings early in the morning. This is when the gas and metal of the
cabinet will be at the closest temperature.

c. The temperature of the SF6 tank should be checked and used as the gas
temperature.

d. See the SF6 Pressure vs. Temperature Table (Figure 4.4.), for pressure at the
recorded temperature.

SF6 Gas Temperature vs. Pressure

Temperature Pressure

In Degree C In Degree F PSIG

-30 -22 57

-20 -4 60

-10 14 64

0 32 68

10 50 71

20 68 75

30 86 79

40 104 82

50 122 86

60 140 90

Figure 4.4. SF6 Gas, Pressure vs. Temperature Table

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Chapter 4 - SF6 Gas System

Figure 4.5. SF6 Pressure versus Temperature Curve

4.7 OPTIONAL PRESSURE SYSTEM - INDIVIDUAL PHASE MONITORING

An optional SF6 system is used on many of the circuit breakers provided by HITACHI HVB, Inc.
Essentially this system is the same as the system covered beginning on page 2 of Chapter 4,
with the addition of lines for each phase’s tank connected to a separate pressure monitor.
This system is available on any model offered by HVB and provides single phase monitoring
rather than the manifold system that monitors the total circuit breaker as a single source of
SF6 gas. The three-phase system provides for command and alarm switches for each pole.
All information regarding adjustment, settings and system pressures should be the same as
previously described for single phase monitoring. The only difference is the number of
pressure gauges or switches and regular pressure gauges (3) now would reflect the number
of poles.
The customers “Device Sheet” and “Electrical Diagrams” should be referenced to determine
the system provided.

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Chapter 4 - SF6 Gas System

Rupture Disc

Figure 4.6. Optional Pressure System

4.8 PULLING VACUUM

In the event that the SF6 gas was removed and the GCB was vented to the atmosphere it is
necessary to replace the gas. Before filling the breaker with SF6 gas it is necessary to replace
the desiccant and pull a vacuum on the GCB. The procedure is as follows:
1. Replace desiccant in the circuit breaker with fresh desiccant. Pull vacuum until a reading

of 1000 microns is reached. This pressure should be held for 2 hours once reaching 1000
microns.

NOTE
For instrument references 1000 microns is equal to one millimeter of mercury
and the same as one Torr.

2. Close the gas-filling valve before attaching the vacuum unit and do not open until the
vacuum is running. Always close the gas-filling valve before stopping the vacuum pump.
Failure to close the gas-filling valve first may result in oil being drawn from the pump into
the tank.

3. Normal evacuation equipment will reach 1000 microns within approximately one-half
hour.

4. Do not evacuate unless SF6 gas is available and will be added the same day. Enough gas
should be added to a minimum of five psig, but normal operating pressure is
recommended.

4.9 O - RINGS AND GASKETS INSTALLATION

O-rings and gaskets are used in the design of the gas circuit breaker and it is important that
the O-rings and gaskets are handled properly to avoid leakage problems. Emphasis must be
placed on the importance of using only factory approved O-rings and gaskets in any location.

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