Circuit Breaker
STANDARDS
• IEC 62271-100
High-voltage switchgear and controlgear –
Alternating-current circuit-breakers
Definition
“A mechanical switching device capable of making,
carrying, and breaking currents under normal circuit
conditions and also making, carrying, and breaking
for a specified time, and breaking currents under
specified abnormal conditions such as a short
circuit.”
[ IEEE Standard C.37.100-1992 ]
Type of Circuit Breakers
1.
2.
3.
4.
5.
Air magnetic
Air blast
Oil
SF6 gas
Vacuum
Oil Circuit Breaker
Three Tank Bulk Oil
Circuit Breaker
Minimum Oil
Circuit Breaker
SF6 Circuit Breaker
Dead Tank SF6
Circuit Breaker
Live Tank SF6
Circuit Breaker
72.5kV SF6 Circuit Breaker
Typical 420kVSF6
Circuit Breaker
Grading Capacitor
Circuit Breaker with Opening Resistors
and Grading Capacitor
SF6 Puffer Type Breaker Operation
Puffer (piston) method showing the 4 stages of the opening process, a) closed position,
b) beginning of the opening movement, c) arcing contacts separate, d) open position, 1
fixed continuous current contact, 2 fixed arcing contact, 3 movable arcing contact, 4
movable continuous current contact, 5 compression cylinder, 6 compression piston, 7
actuating rod, 8 quenching nozzle
Puffer Principle
Closed
Opening
Open
Vacuum Circuit
Breaker
Technical Specification
1.
2.
3.
4.
5.
6.
Type designation for breaker
Class
Rated Voltage
Rated Frequency
Whether single pole or 3-pole operation
Rated Lightning Impulse Withstand Voltage
a) To earth
b) Across open circuit breaker
7.
Rated Switching Impulse Withstand Voltage
a) To earth
b) Across open circuit breaker
8.
Rated Power Frequency Withstand Voltage
a) To earth
b) Across open circuit breaker
Rated insulation levels for
rated voltages of range I
(1kV < Um ≤ 245 kV)
[IEC 60071-1 Table 2]
Rated insulation levels for
rated voltages of range II
(Um > 245 kV)
[IEC 60071-1 Table 3]
Rated insulation levels for rated voltages of range II
[IEC 62271-1 Table2a]
Rated insulation levels for rated voltages of range II
(Um > 800 kV)
[IEC 62271-1 Amend.1 : 2011 Table2a]
Values of rated insulation levels for 1kV < Um ≤ 245 kV for highest
voltages for equipment Um not standardized by IEC based on current
practice in some countries
[IEC 62271-1 Table B.1]
Altitude Correction Factor [Fig.1 IEC 62271-1]
Technical Specification
9.
Rated Current
10. Rated short time withstand current
11. Rated short circuit breaking current
a) AC Component
b) DC Component
12. Rated short circuit making current
Determination of short-circuit making and breaking
currents, and of percentage d.c. component
[IEC 62271-100:2008 Fig.8]
IMC : making current
IAC : peak value of a.c. component
: percentage value of the d.c. component
Technical Specification
13. Rated out of phase breaking current
14. First pole to clear factor
Out-of-Phase Condition
X1
X2
U1
U2
I OOP  0.25I sc
First Pole to Clear Factor (kpp)
• The first-pole-to clear factor is the ratio of the power
frequency voltage across the first interrupting pole, before
current interruption in the other poles, to the power frequency
voltage occurring across the pole after interruption in all three
poles.
First Pole to Clear Factor (kpp)
• For systems with non-effectively grounded neutral, kpp is 1.5.
• For three-phase to ground faults in systems with effectively
earthed neutral, kpp is 1.3.
Technical Specification
15. Rated small inductive breaking current
16. Rated line charging breaking current
17. Rated cable charging breaking current
Preferred values of rated capacitive switching currents
[Table9 IEC 62271-100:2008]
Technical Specification
18. Transient Recovery Voltage (TRV)
a) terminal line faults
b) short line faults
Transient Recovery Voltage (TRV)
 The recovery voltage is the voltage which appears across the
terminals of a pole of circuit breaker after current interruption.
Standard values of TRV for
class S1 circuit-breakers
1kV < Ur ≤ 72.5 kV
[Table1 IEC 62271-100:2008]
Standard values of TRV
for class S2 circuit-breakers
15kV ≤ Ur ≤ 72.5 kV
[Table2 IEC 62271-100:2008]
Standard values of TRV for effectively earthed systems
100kV ≤ Ur ≤ 170 kV
[Table3 IEC 62271-100:2008]
Standard values of TRV for non-effectively earthed systems
100kV ≤ Ur ≤ 170 kV
[Table4 IEC 62271-100:2008]
Standard values of
TRV for effectively
earthed systems
Ur ≥ 245 kV
[Table5 IEC 62271100:2008]
Technical Specification
19. Rated operating sequence
20. Rated
a) Break time
b) Opening time
c) Closing time
21. Number of breaking operation before inspection
and maintenance of contact:
a) At 100% rated current
b) At 50% Short circuit current
c) At 100% Short circuit current
Max. permissible number of interruptions as a function
of the breaking current for 400kV Alstom CB.
Max. permissible
number of interruptions
as a function
of the breaking current
for 400kV Siemens CB.
Technical Specification
22. Min. creepage distance
23. For SF6 circuit breaker:
a) Nominal service gas pressure
b) Gas refill alarm pressure
c) Blocking gas pressure
d) Total volume of the gas
24. Operating mechanism:
a) Type of mechanism
b) Motor Type
c) Motor and control voltage
d) Heater voltage
e) Time required by motor to charge the spring completely
f) Degree of protection of operating mechanism
Outline Drawing