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3 Operation Theory
PCS-978 Transformer Relay
3-75
Date: 2013-01-16
element, zero-sequence impedance element and DPFC inter-turn fault detector element. Three
elements can improve relay sensitivity and ensure relay against maloperation during external
faults, transient process (such as series compensated lines, LC resonance, power swing etc.) or
abnormal conditions (such as pole disagreement, CT secondary circuit failure, etc.)
In order to avoid maloperation of inter-turn fault protection during some transient conditions, such
as pole disagreement operation of lines (or compensated lines), reclosing of auto-recloser after
earth faults, pole disagreement of circuit breaker
,
reactor energization with line (or compensated
line), LC resonance due to circuit breakers at line both sides being tripped, external faults and pole
disagreement with power swing, etc., Residual power directional element and zero-sequence
impedance element are adopted to consist inter-turn fault protection of reactor.
3.6.3.2 Fault Detector
The pickup of this fault detector (DPFC inter-turn fault detector) will enable the inter-turn fault
differential protection, and its operation equation is as follows.
2
1
25
.
1
I
I
I
I
I
I
d
dth
dt
d
Equation 3.6-1
Where:
dt
I
is the floating threshold varied with the change of load current from time to time. The change
of load current is small and gradually under normal or even power swing condition, and the
adaptive floating threshold (
dt
I
) is higher than the change of current under these conditions and
hence the element maintains stability.
1
I
,
2
I
are the DPFC current of two ends of reactor representatively.
d
I
is the DPFC differential current.
d th
I
is the fixed threshold and the value is 0.2pu.
3.6.3.3 Residual Power Directional Element
3.6.3.3.1 Analysis of Inter-Turn Fault of Reactor
The wiring diagram of shunt reactors in power system is shown as following figure.
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 ...