NR Electric PCS-9611, Instruction Manual

Page: 46 / 300

3 Operation Theory
PCS-9611 Feeder Relay
3-10
Date: 2014-04-08
Where:
[50/51P.Upp_VCE] is the voltage setting of the undervoltage control element;
[50/51P.U2_VCE] is the voltage setting of the negative sequence voltage control element;
[VTS.En] is the logic setting of the protection voltage transformer supervision function;
[50/51P1.En_VCE] is the logic setting of the voltage control element for the OC1 protection;
[50/51P.En_VTS_Blk] is the logic setting of the function which can block all the OC protective
elements that relate to the voltage measurement when the voltage transformer is failed;
[VTS.Alm] is the alarm signal of the protection voltage transformer supervision;
[BI_En_VT] is the binary input for denoting the local VT is in service;
[BI_VCE_CrossCtrl] is the binary input for inputting the external voltage control signal;
[50/51P.En_VCE_CrossCtrl] is the logic setting of the external voltage control function.
The logic diagram of the local voltage control signal is shown as below. This device can output the
signal
“Sig_VCE” through the binary output (preconfigured through the PCS-Explorer).
Prot.OnLoad
&
[VTS.Alm]
Uca < [50/51P.Upp_VCE]
Ubc < [50/51P.Upp_VCE]
Uab < [50/51P.Upp_VCE]
[
BI_En_VT
]
U2 > [50/51P.U2_VCE]
Sig_VCE
&
50ms 50ms
Figure 3.3-6 Logic diagram of the OC1 phase A voltage control element
Where:
[50/51P.Upp_VCE] is the voltage setting of the undervoltage control element;
[50/51P.U2_VCE] is the voltage setting of the negative sequence voltage control element;
[BI_En_VT] is the binary input for denoting the local VT is in service;
[VTS.Alm] is the alarm signal of the protection voltage transformer supervision;
“Prot.OnLoad” denotes anyone of the three phase currents is greater than 0.04In.
3.3.4 Directional Element for Overcurrent Protection
The phase fault elements of this relay are internally polarized by the quadrature phase -to-phase
voltages, as shown in the table below:
Phase of Protection Operate Current Polarizing Voltage
A Phase Ia Ubc
B Phase Ib Uca
C Phase Ic Uab