Tests Of Circuit Breker

 Tests Of Circuit Breker

Dielectric tests : 

To check characteristics of Circuit breaker for the following tests:

I) Dry, wet, power frequency
II) Lightning impulse voltage
III) Switching impulse voltage ( applicable for 420 kV CB and above)

Radio Interference voltage test :

To determine RIV on CB pole in both close & open position

Resistance of the main circuit : 

To record circuit resistance during temp. rise test at 200 C

Temp. rise test : 

To ensure capability of contacts to carry rated normal current within specified temp. rise limits

Short-time withstand current & peak withstand current : 

To check the ability of the circuit to carry the maximum rated short-circuit withstand current ( 2.5 times the RMS value) at 50 Hz in close position during the specified short-term duration of 1 or 3 sec.

Mechanical operation test at ambient temp :

To check the characteristics of the breaker for 2000 operations on each pole ( with multiple circuit breaker with individual drive) OR complete assembled breaker (mechanically gang-operated breaker with one common drive)

Short-circuit current making/ breaking tests : 

To check ability of the CB to clear the current on different tests in symmetrical & asymmetrical conditions as per provisions of IEC

Capacitive current charging tests:

-Line charging current breaking tests

-Cable charging current breaking tests

To check withstand capability of the CB for no load transient lines, cables , and capacitor banks

ROUTINE TESTS : 

1- Dielectric test on main circuit

To check the dielectric’s withstand capability of live terminals to live terminals and to earth in both close & open condition of CB

2- Dielectric test on auxiliary & control circuit :

To check the dielectric’s withstand capability of auxiliary & control circuit of CB subject to short duration (60 sec) voltage withstand test for 2 kV . ( For motor or other devices , they are subjected to a dielectric test as per appropriate specs.)

3- Design identification test : 

Verifies the CB for compliances in terms of language of name plate, identification of aux. Equipment, colour & quality of paint etc.

4- Mechanical operating test :
Includes
1) 5 open-close operations at max. rated and minimum control voltage
2) 5 close-open operation at rated control voltage
3) recording opening & closing times at the rated operating pressure & voltage

5- Measurement of resistance of main circuit :
To record contact resistance of CB for mechanical operations to be within specified limits