7SA511 Line Protection Relay

Commissioning the Relay

2.Turn on the DC voltage for the reverse interlocking. The test as described above is repeated, with the same result.

3.Simulate a trip on each protective device on all outgoing feeders. Simultaneously, a short circuit is simulated on the incoming feeder (as described before). Tripping now occurs after delay T1.

4.These tests have simultaneously proved that the pilot wires are functioning correctly; therefore, all other tests described in section 7.3.3 can be skipped.

Carrier Transmission With Release Signal

With permissive overreach transfer trip (POTT) using release signal transmission, it is simple to check the carrier system from one end of the line with the echo function. This test is to be performed from both line ends, and the echo function must be turned on at both line ends.

Prerequisite Settings

Addr. LCD Text

7804 TELEPROTEC.

2201 POTT MODE

2202

POTT MODE

 

 

2220

ECHO

 

 

Description

Type of pilot protection scheme

Turn the permissive overreach transfer scheme on and off

Mode of operation for permis- sive overreach transfer scheme

Turn the echo function on and off

Setting

OVERREACH

ON

Z1B RELEASE or

FD DIREC RELEASE or

￿Z1B UNBLOCK or

FD UNBLOCK

ON (at both line ends)

Test Procedure

1.Simulate a short circuit in Z1B beyond Z1. Since the relay at the other line end has not picked up on fault, the echo function will be effective at that end and a trip signal results.

2.The effect of the echo delay time and the input of the circuit breaker position can be checked at this time. With the following tests, the echo function of the relay at the opposite line end is checked.

a)The circuit breakers at both line ends must be open. A short circuit is simulated as above. Because of the echo function of the relay at the opposite line end, the signal is received and a trip signal occurs at once.

b)Close the circuit breaker at the opposite line end. Repeat above test once more. Received signal and trip command occur again but now with an additional delay caused by the echo delay time at the opposite line end (0.2 seconds as delivered, see address 2221).

c)If delayed and undelayed echo are interchanged, the function mode (NO/NC operation) of the binary input for the circuit breaker position could be wrong. Check and correct it at

7-10

July 27, 1995

Page 164
Image 164
Siemens 7SA511 manual Carrier Transmission With Release Signal, Echo