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3 Operation Theory
PCS-978 Transformer Relay
3-1
Date: 2013-01-16
3.1 Overview
The equipment consists of current differential protection, restricted earth fault protection,
overexcitation protection, phase overcurrent protection, directional ground overcurrent protection,
phase overvoltage protection, undervoltage protection, ground overvoltage protection, thermal
overload protection, and ancillary functions of current transformer and voltage transformer
supervision.
The equipment has 2 plug-in modules (i.e. protection DSP module and fault detector DSP module)
for protection calculation. Protection DSP module is responsible for calculation of protection
elements, and fault detector DSP module is responsible for calculation of general fault detector
element to determine fault appearance on the protected power system. General fault detector
picks up to provide positive supply to output relays. The output relays can only operate when both
a protection element and the corresponding general fault detector operate simultaneously.
Otherwise, the output relays would not operate. An alarm message will be issued with blocking
output if a protection element operates while the corresponding general fault detector does not
operate.
The fault detector of fault detector DSP module consists of several independent fault detector
elements, which can monitor corresponding protection elements without influence to other
protection elements. For example, biased current differential protection will not release trip
command until both protection element of protection DSP module and the corresponding fault
detector of fault detector DSP module operate simultaneously. Furthermore, if there is a hardware
fault on one DSP module or the differential current is at the trip boundary, the inconsistent pickup
of fault detectors of biased current differential protection on two DSP modules will occur.
3.2 Transformer Current Differential Protection (87T)
3.2.1 Application
In power system, the power transformer is one of most valuable and expensive equipment. If a
fault occurs in the protection zone of a transformer, current differential protection operates quickly
to clear the fault to avoid the transformer from damages or reduce the maintenance cost as low as
possible.
3.2.2 Function
Maximum 6 group CT inputs for differential protection.
Protection for 2-winding, 3-winding transformer and auto-transformer.
24 vector groups available for two-winding transformer.
288 vector groups available for 3-winding transformer.
Optional inrush current distinguished principles: harmonic criterion (second harmonic and
third harmonic) or waveform distortion.
Содержание PCS-978
Страница 1: ...PCS 978 Transformer Relay Instruction Manual NR Electric Co Ltd ...
Страница 2: ......
Страница 6: ...Preface PCS 978 Transformer Relay IV Date 2013 01 16 ...
Страница 10: ...Preface PCS 978 Transformer Relay VIII Date 2013 01 16 ...
Страница 62: ...3 Operation Theory PCS 978 Transformer Relay 3 p Date 2013 01 16 ...
Страница 250: ...4 Supervision PCS 978 Transformer Relay 4 b Date 2013 01 16 ...
Страница 264: ...4 Supervision PCS 978 Transformer Relay 4 14 Date 2013 01 16 ...
Страница 266: ...5 Management PCS 978 Transformer Relay 5 b Date 2013 01 16 ...
Страница 272: ...5 Management PCS 978 Transformer Relay 5 6 Date 2013 01 16 ...
Страница 334: ...6 Hardware Description PCS 978 Transformer Relay 6 60 Date 2013 01 16 ...
Страница 370: ...8 Human Machine Interface PCS 978 Transformer Relay 8 d Date 2013 01 16 ...
Страница 404: ...8 Human Machine Interface PCS 978 Transformer Relay 8 34 Date 2013 01 16 ...
Страница 406: ...9 Configurable Function PCS 978 Transformer Relay 9 b Date 2013 01 16 ...
Страница 446: ...10 Communication PCS 978 Transformer Relay 10 26 Date 2013 01 16 ...
Страница 448: ...11 Installation PCS 978 Transformer Relay 11 b Date 2012 10 09 ...
Страница 456: ...11 Installation PCS 978 Transformer Relay 11 8 Date 2012 10 09 ...
Страница 458: ...12 Commissioning PCS 978 Transformer Relay 12 b Date 2012 12 07 ...
Страница 468: ...12 Commissioning PCS 978 Transformer Relay 12 10 Date 2012 12 07 ...
Страница 470: ...13 Maintenance PCS 978 Transformer Relay 13 b Date 2012 10 09 ...
Страница 474: ...13 Maintenance PCS 978 Transformer Relay 13 4 Date 2012 10 09 ...
Страница 476: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 b Date 2012 10 09 ...
Страница 478: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 2 Date 2012 10 09 ...
Страница 480: ...15 Manual Version History PCS 978 Transformer Relay 15 2 Date 2013 01 16 ...