is slightly above 0.25 A on the secondary side. The corresponding trip signals TROC and
TRIP will be activated after the pre-set time delay has expired.
5.
Decrease the current IL1 slowly and note the reset value.
6.
Repeat steps 4 and 5 applying voltages that are related to the second and the last
section of the characteristic; the function operates when IL1 is slightly higher than: 0.5 A
in the second section; 1A in the last section.
7.
Connect the trip output contact to the input channel of the test set in order to stop the
injection and measure the trip time.
8.
If definite time delay is used for the overcurrent step, set the setting
Characterist = IEC
Def. Time. Apply the voltages related to the last part of the characteristic and inject a
current IL1 200% higher than the set operation level, and check the definite time delay for
trip (the signals TROC and TRIP of the protection function VRPVOC are active in trip
condition).
9.
If inverse time delay is used for the overcurrent step, the parameter setting
Characterist
shall be properly set; we can refer, for example, to the setting
IEC Very inv.; If the IEC Very
inverse time characteristic is selected, the trip signals TROC and TRIP will operate after a
time defined by the equation:
t s
k
I
StartCurr
[ ]
=
−
13 5
1
. *
IECEQUATION2435 V1 EN-US
(Equation 92)
where:
t
Operate time in seconds
I
Measured value (for example, phase current)
StartCurr Set operate value
This means that if the measured phase current jumps from 0 to 2 times the set operate
level and time multiplier k is set to 1.0 s (default value), then the TROC and TRIP signals
will operate after a time delay equal to 13.5 s ± tolerance.
Taking into account the above explanation, inject the voltages related to the last part of
the characteristic and inject a current IL1 200% higher than the set operation level, and
check the trip time delay.
If
tDef_OC is set to a value different from 0 s, then this time delay is
added to the one that is defined by the IDMT characteristic.
10. Check the start and operate information that are stored in the event menu.
11.
The previous step 8 or 9 may be repeated also for the first and second section of the
characteristic.
12.
Supply the IED with symmetric three-phase voltages at their rated values. Go to Main
menu/Settings/IED Settings/Current protection/VoltageRestOverCurr(51V,2(I>/U<))/
VRPVOC(51V,2(I>/U<)):1/Undervoltage and set the setting
Operation_UV = On to
activate the undervoltage stage.
13. Slowly decrease the voltage in two phases simultaneously, until the STUV and START
signals appear.
14. Note the operate value. The set operate value in secondary volts is calculated according
to the following equation:
StartVolt
UBase
VT
VTprim
100
3
×
×
sec
IECEQUATION2436 V1 EN-US
(Equation 93)
Section 12
1MRK 502 067-UEN B
Testing functionality by secondary injection
180
Commissioning manual
