3 Operation Theory
PCS-978 Transformer Relay
3-141
Date: 2013-01-16
3.15 Phase Overvoltage Protection (59P)
3.15.1 Application
In the power system, when users operating circuit breakers or a fault occurring, system
parameters will change, which can cause the power system electromagnetic energy converting
and transferring and overvoltage will appears in the system. Overvoltage protection is equipped for
the protection of electric equipment and its insulation.
3.15.2 Function
Phase overvoltage protection has following functions:
Two-stage phase overvoltage protection with independent logic, voltage and time delay
settings.
Stage 1 and stage 2 definite-time characteristic, stage 2 can be selected as definite-time or
inverse-time characteristic. The inverse-time characteristic is selectable among IEC and
ANSI/IEEE standard inverse-time characteristics and a user-defined inverse-time curve.
Phase voltage or phase-to-phase voltage can be selected for protection calculation.
“1 out of 3” or “3 out of 3” logic can be selected for protection criterion.
3.15.3 Protection Principle
3.15.3.1 Operation Criterion
Users can select phase voltage or phase-to-phase voltage for the protection calculation. If setting
[
x.
59Pn.En_Vpp] is set to “0”, phase voltage criterion is selected and if [
x.
59Pn_En_Vpp] is set to
“1”, phase-to-phase voltage criterion is selected.
When phase voltage or phase-to-phase voltage is greater than one stage voltage setting,
corresponding stage protection picks up and operate after delay, which will drop off
instantaneously when fault voltage disappears.
Phase voltage criterion
Two operation criteria of definite-time overvoltage protection are as follows, which of them is
selected depending on the logic setting [
x.
59Pn.Opt_1P/3P].
max
_
U
[ x.59Pn.U_Set]
Equation 3.15-1
Set]
[x.59Pn.U_
>
U
Set]
[x.59Pn.U_
>
U
Set]
[x.59Pn.U_
>
U
c
b
a
Equation 3.15-2
Where:
Summary of Contents for PCS-978
Page 1: ...PCS 978 Transformer Relay Instruction Manual NR Electric Co Ltd ...
Page 2: ......
Page 6: ...Preface PCS 978 Transformer Relay IV Date 2013 01 16 ...
Page 10: ...Preface PCS 978 Transformer Relay VIII Date 2013 01 16 ...
Page 62: ...3 Operation Theory PCS 978 Transformer Relay 3 p Date 2013 01 16 ...
Page 250: ...4 Supervision PCS 978 Transformer Relay 4 b Date 2013 01 16 ...
Page 264: ...4 Supervision PCS 978 Transformer Relay 4 14 Date 2013 01 16 ...
Page 266: ...5 Management PCS 978 Transformer Relay 5 b Date 2013 01 16 ...
Page 272: ...5 Management PCS 978 Transformer Relay 5 6 Date 2013 01 16 ...
Page 334: ...6 Hardware Description PCS 978 Transformer Relay 6 60 Date 2013 01 16 ...
Page 370: ...8 Human Machine Interface PCS 978 Transformer Relay 8 d Date 2013 01 16 ...
Page 404: ...8 Human Machine Interface PCS 978 Transformer Relay 8 34 Date 2013 01 16 ...
Page 406: ...9 Configurable Function PCS 978 Transformer Relay 9 b Date 2013 01 16 ...
Page 446: ...10 Communication PCS 978 Transformer Relay 10 26 Date 2013 01 16 ...
Page 448: ...11 Installation PCS 978 Transformer Relay 11 b Date 2012 10 09 ...
Page 456: ...11 Installation PCS 978 Transformer Relay 11 8 Date 2012 10 09 ...
Page 458: ...12 Commissioning PCS 978 Transformer Relay 12 b Date 2012 12 07 ...
Page 468: ...12 Commissioning PCS 978 Transformer Relay 12 10 Date 2012 12 07 ...
Page 470: ...13 Maintenance PCS 978 Transformer Relay 13 b Date 2012 10 09 ...
Page 474: ...13 Maintenance PCS 978 Transformer Relay 13 4 Date 2012 10 09 ...
Page 476: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 b Date 2012 10 09 ...
Page 478: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 2 Date 2012 10 09 ...
Page 480: ...15 Manual Version History PCS 978 Transformer Relay 15 2 Date 2013 01 16 ...