59 Overvoltage Protection - 3 Phase; Neutral Voltage Displacement - Siemens Reyrolle 7SR5 Manual

59 Overvoltage Protection – 3 Phase
9.10.16
Where more than 1 overvoltage (59) elements are being used with different settings, it is convenient to test
the elements with the highest settings first. The elements with lower settings can then be tested without disa-
bling the higher settings.
If the O/P Phases is set to All, the voltage on all phases must be increased simultaneously. Otherwise the 3
phases can be tested individually. There is a common setting for to select the voltage to be measured as
phase-phase or phase-neutral. If the DTL setting is short, starting from nominal voltage, slowly increase the
applied 3P or VL1 test voltage until the Pickup LED (temporarily mapped) is on. The LED should light at
setting Volts ±5 % decrease the input voltage to nominal Volts and the LED will extinguish. Record the
reset voltage to check the Hysteresis setting. If the DTL setting is long, the operate level can be checked by
applying 100 % of setting to cause operation followed by setting minus the Hysteresis setting to cause
reset.
Connect the relevant output contact(s) to stop the test set. Step the applied voltage to a level above the
setting. The test set should be stopped at the Operate Time setting ±5 % test the other phases by repeating
the above if necessary.
Phase Setting
(Volts)
V (V )
A AB
V BC
B AB
)
V CA
C AB
)
Element Blocking
The Under/Over Voltage elements can be blocked by Binary Input Inhibit and VT Supervision.
This functionality should be checked.
Element
59-1
59-2
59-3
59-4
When testing is complete reinstate any of the disabled functions.
59N Neutral Voltage Displacement
9.10.17
The normal voltage source for the Neutral Overvoltage 59N function is V
3 phase voltage inputs but it can be configured to operate from the single phase V4 input. To test, apply test
voltage to 1 phase input.
Definite Time (59NDT)
If DTL setting is small, gradually increase single phase voltage until element operates.
If DTL is large apply 0.9 times setting, check for no operation, apply 1.1 times setting, check operation.
Apply 2 times setting voltage if possible and record operating time.
Phase
E
Check correct indication, trip output, alarm contacts, waveform record.
Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019
U/O DTL Hyst.
(sec)
BI Inhibits
Setting (Volts) Delay (sec)
D.O. P.U. D.O
(calcu- Volts Volts
lated)
P.U. Current
(Volts)
Functional Tests
9.10 Protection Functional Tests
Op. Time @ 1.2 UV
⋅ V (OV) @ Guard
set
0.5 ⋅ V (UV)
set
VT Supervision
, calculated from the applied
rated
Op. Time @ 2 ⋅ Tolerance
V
set
Toler-
ance
441