purposes. Make sure that all built-in features for this function, which shall be in operation, are
enabled and with correct settings.
12.6
Voltage protection
SEMOD53540-1 v1
12.6.1
Two step undervoltage protection UV2PTUV
M13796-2 v6
Prepare the IED for verification of settings as outlined in section
in this chapter.
12.6.1.1
Verifying the settings
M13796-9 v3
Verification of START value and time delay to operate for Step 1
M13796-29 v9
1.
Check that the IED settings are appropriate, especially the START value, the definite time
delay and the
1 out of 3 operation mode.
2.
Supply the IED with three-phase voltages at their rated values.
3.
Slowly decrease the voltage in one of the phases, until the START signal appears.
4.
Note the operate value and compare it with the set value.
The operate value in secondary volts is calculated according to the
following equations:
For phase-to-earth measurement:
U
UBase
VT
VTprim
1
100
3
<
×
×
sec
IECEQUATION2430 V1 EN-US
(Equation 94)
For phase-to-phase measurement:
U
UBase
VT
VTprim
1
100
<
×
×
sec
IECEQUATION2431 V1 EN-US
(Equation 95)
5.
Increase the measured voltage to rated load conditions.
6.
Check that the START signal resets.
7.
Instantaneously decrease the voltage in one phase to a value about 20% lower than the
measured operate value.
8.
Measure the time delay for the TRIP signal, and compare it with the set value.
9.
Check the inverse time delay by injecting a voltage corresponding to 0.8 × U1<.
For example, if the inverse time curve A is selected, the trip signals TR1
and TRIP operate after a time corresponding to the equation:
t s
k
U
U
( )
=
−
<
1
1
1
IECEQUATION2428 V1 EN-US
(Equation 96)
where:
t(s)
Operate time in seconds
1MRK 502 067-UEN B
Section 12
Testing functionality by secondary injection
183
Commissioning manual
