Page 140 - Practical Power System and Protective Relays Commissioning

138 Practical Power System and Protective Relays Commissioning

12.2 DISCONNECT SWITCHES/EARTH (GROUNDING)
SWITCHES TESTS

This includes the following tests:
1. Mechanical check and function test including open/close and electrical
and mechanical interlocks
a. Check the horizontal level of the disconnecting switch in the open
and close positions.
b. Measure the distance between the axis of the two isolators of the dis-
connecting switch as per the drawings.
c. Check that the mechanical indicator of the disconnecting switch is
correct for the open and close positions.
d. Check for the mechanical interlocks between the disconnecting switch
and its ES.
2. Operating time test
a. This test can be done using a stop watch.
3. Contact resistance test
a. This test is done by micro-Ohm meter tester which injects 100 DC
Amp and is connected as shown in Fig. 12.8.

FIGURE 12.8 Contact resistance measurement of the disconnecting switch.