NR Electric PCS-9611, Instruction Manual

Page: 111 / 300

4 Supervision
PCS-9611 Feeder Relay
4-3
Date: 2014-04-08
protection VT is in abnormal status.
(1) The negative phase sequence voltage is greater than 8V.
(2) The positive phase sequence voltage is less than 30V, and any of the phase currents is
greater than 0.04In.
Then the alarm signals [Alm_Device] and [VTS.Alm] are issued 10s later, and the LED
“
ALARM
” will be on at the same time. When the protection VT status returns to normal
condition, the alarm will restore automatically 1.25s later. In case the protection VT circuit is
failed, these protective elements dependent on voltage will be blocked.
If the fast VT failure is detected, the internal signal
“VTS.InstAlm” will be “1” without any time
delay. In the fast VTS element, the phase current or the negative sequence current must be
taken into account.
The logic diagram of the protection VTS element is shown as below.
VTS.InstAlm
&
&
&
[VTS.Alm]
U
1
< 30V
U
2
> 8V
Ic < [VTS.I_Set]
Ib < [VTS.I_Set]
Ia < [VTS.I_Set]
I
2
< [VTS.I2_Set]
[VTS.En]
[Sig_MCB_VT]
&
&
Prot.OnLoad
&
U
1
< 15V
10s 0
[
BI_En_VT
]
&
Figure 4.2-2 Logic diagram of the protection VTS element
Where:
“Prot.OnLoad” is the signal for denoting the system is on load state;
[VTS.En] is the logic setting of the protection VTS function;
[VTS.I_Set] is the phase current setting of the protection VTS function;
[VTS.I2_Set] is the negative sequence current setting of the protection VTS function;
[Sig_MCB_VT] is the VT supervision input from VT
’s miniature circuit breaker (MCB)
auxiliary contact which shows the MCB whether is opened;
[BI_En_VT] is the binary input for denoting the local VT is in service;
“U
1
” is the positive sequence voltage;
“U
2
” is the negative sequence voltage.

Synchro-check VT supervision
This function is used to supervise the synchro-check voltage transformer circuit. When the