Testing Of The Undervoltage Stages; Low-Set Stage U - ABB REU 513 User Manual

REU 513
2.3.
2.3.1.
64
User's Guide
Inverse-time characteristic
At inverse-time characteristic, the operate time is measured at two different test
voltage values (1.1 x U>> and 1.4 x U>>). The operate times thus obtained are
compared with the operate times obtained from the voltage/time curves of the
concerned inverse-time characteristic.
• Set the test voltage at one of the two defined test voltages.
• Switch off S1 and clear indicators and reset output relays. The clock is started
by closing switch S1 and stopped by closing output contact PO2.

Testing of the undervoltage stages

The test is carried out as a single-phase test and the relay should be configured
accordingly by setting SGF2/1=1.
Before the test is started:
• Record actual SGR and SGF2 settings for later restoring.
• Set the relay switchgroups as follows:
Table 52: Settings of switchgroups
SGR
SGR5 = 4
Setting U< to SO1
Setting values can be those actual used.
Low-set stage U<
Starting
• Set the test voltage value at a value slightly above the set start value of stage U<.
• Close switch S1 and clear indicators and reset output relays.
• Slowly lower the voltage until the relay starts and the indicator L3 is lit. Then
read the start voltage value from the voltmeter.
Operate time
Test according to selected characteristics.
Definite-time characteristic
• Set the test voltage at 1.1 x the set start value of stage U<. The clock is started
by opening switch S1 and stopped by closing output contact PO1.
• When the relay starts, the START indicator is lit with yellow light. When the
relay operates, the TRIP indicator is lit with red light.
Inverse-time characteristic
At inverse-time characteristic, the operate time is measured at two different test
voltage values (0.9 x U< and 0.6 x U<). The operate times thus obtained are
ABB Substation Automation
SGR6 = 1 SGR7 = 8
t< to PO1 U<< to SO2
Products and Systems
SGR8 = 2
t<< to PO2
1MRS750886-MUM