Siemens 7SR242 Duobias - Page 44

7SR242 Duobias Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 44 of 57
The frequency should then be gradually decreased/increased until the element resets. The reset frequency can
be used to check the Hysteresis setting.
If the element is set as 81-n U/V Guarded, The applied voltage must be above the 81 UV Guard Setting in the
U/O Frequency menu.
Apply setting frequency +0.5Hz for Over-frequency or -0.5Hz for Under-frequency and record operating time.
Starting with the element in the operated condition, gradually increase or decrease the applied voltage until the
element resets. Measure the reset voltage level to check the 81 Hysteresis setting.
F
(Hertz)
U/O DTL
(sec)
Hyst. D.O.
(calc.)
P.U.
Freq
Hertz
D.O.
Freq.
Hertz
Operate
Time
+/- 0.5Hz
UV
Guard
NOTES
If the element is set as 81-nU/V Guarded, this setting can be tested by applying the test voltage at a level below
the 81 U/V Guard Setting at a frequency in the operate range. Increase the voltage until the relay operates.
UVG UVG Setting
(Volts)
Freq element
Used for test
Blocked
Volts (D.O.)
Unblocked Volts (P.U.) NOTES
U/O Freq
2.11.1.1 Element Blocking
The U/O Frequency elements can be blocked by Binary Input Inhibit. This functionality should be checked.
Element BI Inhibits
81-1
81-2
81-3
81-4
81-5
81-6
Check correct indication, trip output, alarm contacts, waveform record.
When testing is complete reinstate any of the disabled functions.