Protection Engineering Basics and Schemes Protection Engineering | Page 191

Method of Testing:
 Isolate Voltage relay
from system, our PT is
11KV/110V, and system
is star-star connected.
 Confirm zero voltage
status
 Sverker 750/760 is my
device, frequency relay I am testing is SEL 751A.
 Power up SEL 751 A relay through Sverker 750/760
 Open Relay software “AcSelerator”, and set values as
per your requirement, I took 105 % setting, means
whenever our secondary side 52.5Hz (frequency we
have is 50 Hz), relay will pick up. We need to connect
Testing leads to E port from Testing Kit as per figure
3G.
 Raise voltage from line to neutral voltage and note
frequency also increases, increase voltage supply till
frequency reach up to pick up level.
 After Pick up, note all Test values now you need to
reduce supply voltage to Zero level.
 Check it and remove kit connection
pg. 191