Apparatus Control Testing; Panel Internal Interlocking; Circuit Breaker Truck (Disconnector); Figure 50: Blocking Conditions Of The Circuit Breaker Truck In Pcm600 - ABB UniGear Digital Commissioning And Testing Manual

PA N E L I NT ER N A L I NT ER LO C KI NG
5

Apparatus control testing

It is recommended to test panel internal interlocking and interlocks between panels during
maintenance.
5.1

Panel internal interlocking

To prevent hazardous situations and incorrect operation, there is a series of interlocks to pro-
tect both personnel and equipment. Apparatus interlocking is mechanical and electrical. The
protection relay includes designated functions for each apparatus and enables operation by
means of blocking coils. Under medium voltage the switchgear panel can operate only one
apparatus at a time.
5.1.1

Circuit breaker truck (Disconnector)

The circuit breaker truck can only be moved from the Test / Disconnected position
(and back) when the circuit breaker and the earthing switch are off and the earthing
switch crank is not inserted.
The dedicated protection function for supervision of the circuit breaker truck operation is
DCSXWI or DCSXSWI.

Figure 50: Blocking conditions of the circuit breaker truck in PCM600

Step 1/6
Move the circuit breaker into the test position and keep it open. Check the circuit breaker sta-
tus on the protection relay LHMI.

Figure 51: Single line diagram, the circuit breaker is open and in the test position

36
AP PAR ATU S CO NTR O L T E S TI NG
1 VLG 5000 17 C