Directional Element For Overcurrent Protection - NR Electric PCS-9611 Instruction Manual

3 Operation Theory
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]
Uab < [50/51P.Upp_VCE]
Ubc < [50/51P.Upp_VCE]
Uca < [50/51P.Upp_VCE]
U2 > [50/51P.U2_VCE]
[BI_En_VT]
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
A Phase
B Phase
C Phase
3-10
&
50ms 50ms
&
Operate Current
Ia
Ib
Ic
Date: 2014-04-08
Sig_VCE
Polarizing Voltage
Ubc
Uca
Uab
PCS-9611 Feeder Relay