Inverse Time (59Nit) - Siemens 7SR224 Technical Manual

2.12.7 Inverse Time (59NIT)

It will be advantageous to map the function being tested to temporarily drive the relevant Pickup output in the
Pickup Config sub-menu in the Output Config menu as this will allow the Pick-up led to operate for the function.
Gradually increase voltage until Pickup LED operates.
Apply 2x setting voltage and record operating time,
Apply a higher multiple of setting voltage and record operating time.
Compare to calculated values for operating times from:
⎡
( ) 1
=
⎢
t sec onds ) M [ ]
−
op
Vn
⎣
Vs
Where M = Time multiplier and Vn/Vs = multiple of setting.
P.U. Ph. Vs
D.O. (V)
&
TIMING
TESTS
E
2.12.7.1 Element Blocking
The Neutral Overvoltage elements can be blocked by Binary Input Inhibit. This functionality should be checked.
Element
59NIT
59NDT
Check correct indication, trip output, alarm contacts, waveform record.
When testing is complete reinstate any of the disabled functions.
©2010 Siemens Protection Devices Limited
⎤
⎥
1 ⎦
TM Operate Voltage
P.U. D.O.
(Volts) (Volts)
7SR224 Argus Commissioning & Maintenance Guide
Operate Time
2 x Vs x Vs
(sec) (sec)
BI Inhibits
NOTES
Chapter 6 Page 50 of 73