HV Circuit Breakers
PTHV-LTB
Incoming
line
ABB Transformation - Training Module-I
1
CVT
DS/ ES
CT
DS
DS
CT
CB
PI/SA
Trans.
High Voltage Circuit Breakers
HV Circuit Breakers
PTHV-LTB
Incoming
line
ABB Transformation - Training Module-I
2
CVT
DS/ ES
CB
CT
DS
DS
CT
CB
PI/SA
Trans.
BUSBAR
HV Circuit Breakers
PTHV-LTB
LTB
Interrupter
Line
termination
Insulating rod
Mechanical
Link
ABB Transformation - Training Module-I
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Mechanism
HV Circuit Breakers
PTHV-LTB
Line
termination
Interrupter
Line
termination
Insulating rod
Mechanism
ABB Transformation - Training Module-I
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HV Circuit Breakers
• What is a Circuit Breaker ?
– Circuit Breakers are mechanical
switching device, capable of making,
carrying and breaking currents under
normal circuit conditions and also
making, carrying for a specified time and
breaking currents under specified
abnormal conditions such as those of
short circuit (IEC 50 - 441).
– It is a premium against damage of the
equipment.
– It is the only automatic moving
equipment in the transmission system.
– It is a slave of relay.
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
PTHV-LTB
Fault Occurs
Relay
• Senses
• Contact Closes
Circuit Breaker
• Trip Coil Energises
• Operating Mechanism Starts
• Contacts Separate
• Arcing betn. Contacts
• Arc Extinguishes
• CB Fully Opens
ABB Transformation - Training Module-I
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Faulted Part
Gets Isolated
HV Circuit Breakers
• Ratings
– Rated voltage (U r)
– Rated insulation level
– Rated frequency (f r)
– Rated normal current (I r) and
temperature rise
– Rated short time withstand current
(I k)
– Rated peak withstand current (I p)
– Rated duration of short circuit (t k)
– Rated supply voltage of closing and
opening devices and of auxiliary
and control circuits (U a)
– Rated supply frequency of closing
and opening devices and auxiliary
circuits
– Rated pressures of compressed gas
for providing insulation, operation
and/ or interruption.
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
• Classification of CBs
– On principle of current interruption
• SF6 (puffer, self blast), Vacuum,
Bulk oil, Minimum oil, Air break,
Air Blast CB etc.
– On class of voltage
• Medium voltage, High voltage,
Extra High voltage etc.
– Type of installation
• Indoor, outdoor etc.
– Application
• Railway, Generator CB, Line CB,
Transformer CB, Reactor CB,
furnace CB, Bus coupler, etc.
– Type of mechanism
• Pneumatic, spring, Hydraulic,
Hydro-mechanical, springpneumatic, solenoid, motor
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PTHV-LTB
HV Circuit Breakers
PTHV-LTB
• Classification of CBs
– On principle of current interruption
• SF6 (puffer, self blast)
– Present day CBs for medium voltage and high voltage.
– Uses SF6 gas as a interrupting media and insulation media
– Meets almost all technical requirements
• Vacuum
•
•
•
•
–
–
–
–
Uses vacuum as interruption media
Uses SF6 for 36 kV and 52 kV as insulation media
Used mainly for medium voltages
Offers good electrical life
Bulk oil,
Minimum oil,
Air break,
Air Blast CB
ABB Transformation - Training Module-I
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Name suggests the interruption
media. They are now history.
HV Circuit Breakers
PTHV-LTB
• Classification of CBs
– On class of voltage
• Medium voltage
–
–
–
–
From above 1 kV up to 52 kV class voltage
Generally used indoors
Housed in a cubicle
Outdoor is also getting popular in India
• High voltage
– From 72.5 kV up to 300 kV
– short line fault requirement for this voltage and
above
• Extra High voltage
– Above 300 kV
– Switching Impulse withstand requirement Additional
ABB Transformation - Training Module-I
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SF6Circuit
Breakers
HV
Breakers
PTHV-LTB
• Puffer
In these breakers the continuous gas pressure can be kept at low enough
levels, 0.5-0.7 Mpa (abs), to permit operations under most climatic conditions,
without risk of liquefaction. The pressure difference and resulting gas flow
required for interruption are obtained by compression of gas, by operating
mechanism, in direct connection with opening of the contacts.
• Auto-Puffer (Self-Blast)
In self-blast breakers the gas blast that is required is mainly obtained by use of
energy from the arc itself. The arc heats the gas in a compression volume, and
the resulting differential pressure leads to the gas flow used for interruption.
The operating mechanism can be kept smaller and simpler than for
corresponding puffer breakers.
ABB Transformation - Training Module-I
11
AutoCircuit
- Puffer
Principle
HV
Breakers
PTHV-LTB
Extinguishing Position
Closed Position
Small Current
ABB Transformation - Training Module-I
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SC Current
Utilization
Operating Energy
HV Circuit of
Breakers
PTHV-LTB
Compared with a conventional puffer breaker of the same rating,
the energy demand of the self-blast breaker is only around 20 %
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
• Classification of CBs
– Application
• Railway
– In India a standard 50 Hz CB
– Outside India frequency 16 2/3 Hz
– Class of voltage is 25 kV single phase
• Generator CB
– Connected at the terminals of Generator
– High normal current and very high fault current
– High dc component due to low L/R ratio. Missed current zeros.
• Line CB
– A standard CB
– Fault currents can be low or high depending on network
condition
– Can be three phase closing or one phase closing. System
stability requirement
– Capacitive current of the line is to be interrupted
• Transformer CB, Reactor CB
– Three phase operation preferred
– Reactive current chopping can cause system over voltages
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
• Classification of CBs
– Application
• Furnace CB
– Large number of mechanical operations. Large number of
fault operations
• Bus coupler
– Normally works as a switch. It operates generally on load
currents
• Station Auxiliary Breaker
–
–
–
–
Used for switching of station auxiliary power supply.
For example, boiler feed pump, coal handling plant etc.
Normally motor switching. Inductive current.
Over voltages due to switching is of great significance
• HVDC Breaker
ABB Transformation - Training Module-I
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HV Circuit
Single
LineBreakers
Diagram
PTHV-LTB
Capacitor
Side Breaker
Generator
End Breaker
Sending
End Breaker
Receiving
End Breaker
Load
End Breaker
ABB Transformation - Training Module-I
16
HV Circuit Breakers
Current Zero Missed due to Large L/R
•
Initial fault current contains large DC component, which may cause
missed current zero opportunities.
C
u
r
r
e
n
t
time
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
PTHV-LTB
Type of Mechanism
• Spring Charged
– Spring charged using motor to store energy and transferred
through mechanical links
– Spring can be helical, spiral (clock), etc
• Pneumatic
– Energy stored by compressing air in a receiver.
– Energy transmitted pneumatically and motion created using
cylinder piston arrangement
• Hydraulic, Hydro - mechanical
– Energy stored either in compressed air or springs
– Energy transmitted hydraulically and motion created using
cylinder piston arrangement
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HV Circuit Breakers
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
ABB Transformation - Training Module-I
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PTHV-LTB
HV Circuit Breakers
PTHV-LTB
Type of Mechanism
• Motor Mechanism
– Servo motor used to deliver energy.
– Electronics used for delivery of desired energy with respect
to time.
– Energy stored in capacitors
– Used for High voltages also
• Solenoid Mechanism
– Like contactor , electromagnet is used to move contacts
– Energy can be derived from battery or capacitors.
– Used for medium voltages and vacuum CBs
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
ELF 1982
DLF 1974
DCF 1969
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
Type Designation: ELF SL 6-2
Rating
Voltage
: 420 kV
Current
Short circuit : 40 kA
Nominal
: 3150 A
Mechanism
Quantities
delivered
(upto 2000)
ABB Transformation - Training Module-I
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: Pneumatic
Type PKA
: 391
HV Circuit Breakers
PTHV-LTB
Type Designation: ELF SL 4-1
Rating
Voltage
: 245 kV
Current
Short circuit : 40 kA
Nominal
: 3150 A
Mechanism
Quantities
delivered
(upto 2000)
ABB Transformation - Training Module-I
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: Pneumatic
Type PKA
: 2243
HV Circuit Breakers
ABB Transformation - Training Module-I
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PTHV-LTB
Type Designation
Rating
- Voltage
- Current
Short Circuit
Nominal
Mechanism
: ELF SF 2-1/(r)
Quantities delivered
(upto 2000)
:3323
: 145-72.5 kV
: 31.5kA
: 2000 A
: Pneumatic
Type PKA
HV Circuit Breakers
PTHV-LTB
Type Designation: LTB145D1/B
Rating
Voltage
: 145 kV
Current
Short circuit : 40kA
Nominal
: 3150 A
Mechanism
charged
BLK
Quantities
delivered
(upto 2000)
ABB Transformation - Training Module-I
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: Spring
Type
: 702
HV Circuit Breakers
PTHV-LTB
Type Designation: EDF SK 1-1
Rating
Voltage
: 36-52-72.5 kV
Current
Short circuit
: 31.5 kA
Nominal
: 2500 A
Mechanism
: Spring charged
Type FSA
Quantities
delivered
: 4699
(upto 2000)
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
A typical 2 - chamber
breaker for 420 kV class
of voltage
ABB Transformation - Training Module-I
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HV Circuit Breakers
PTHV-LTB
Cross section of a
Interrupting chamber
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