Check Mode For Manual Closing Function - NR Electric PCS-9611 Instruction Manual

3 Operation Theory
[25M.En_DdChk] is the logic setting of the dead check of the manual closing.

3.18.2 Check Mode for Manual Closing Function

This relay provides three check modes for the manual closing function (local or remote closing):
synchronism check mode, dead check mode and non-check mode. Each mode can be selected
through the relevant logic settings.

Synchronism check mode
The following conditions must be satisfied in the synchro check manual closing function.
1. The protection voltage is greater than the setting [25.U_Lv];
2. The synchro-check voltage is greater than [25.U_Lv] / [25.U_Comp];
3. The voltage difference between the protection voltage and the synchro-check voltage
(ΔU = |U - U
Prot
4. The frequency of protection voltage and the frequency of synchro -check voltage are in
the range f
n
5. The frequency difference between the protection voltage and the synchro-check voltage
(Δf = |f - f
Prot Sy n
6. The rate-of-change of the frequency difference (dΔf/dt) is less than the setting [25M.df/dt]
to decrease the disturbance to the power system when the CB is closed;
7. The phase angle difference between the protection voltage and the synchro-check
voltage (Δδ = |Φ
For the details about the settings [25.U_Comp] and [25.phi_Comp], see Section 7.4.1.
If the above conditions are satisfied at the same time, the signal of the synchronism check of
the manual closing "25M.Ok_SynChk" is issued.
When the manual closing operation is executed, this relay checks synchronism check closing
conditions in the period of the setting [25M.t_Wait]. If the synchro check closing conditions
are satisfied, this relay will issue the closing command.
The logic diagram of the manual closing synchronism check element is shown as below.
U
U
ΔU < [25M.U_Diff]
Δf < [25M.f_Diff]
dΔf/dt < [25M.df/dt]
Δδ < [25M.phi_Diff]
[25M.En_SynChk]
Figure 3.18-2 Logic diagram of the synchr onism check element for manual closing
Where:
3-64
× [25.U_Comp]|) is less than the setting [25M.U_Diff];
Sy n
± 5Hz (f : the rated system frequency);
n
|) is less than the setting [25M.f_Diff];
– (Φ
+ [25.phi_Comp])|) is less than the setting [25M.phi_Diff].
Prot Sy n
> [25.U_Lv]
Prot
> [25.U_Lv]/[25.U_Comp]
Syn
Date: 2014-04-08
&
25M.Ok_SynChk
PCS-9611 Feeder Relay