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3 Operation Theory
PCS-978 Transformer Relay
3-67
Date: 2013-01-16
I'_H, I'_H1, I'_H2 and I'_M are primary values of current of each side of transformer respectively.
I'_CW is secondary value of common winding three-phase CT
I'_HBush is secondary value of current of HV side bushing CT
DANGER!
When winding differential protection is used as stub differential protection, the
polarity of CT must be checked. If polarities of the circuit breaker CT and the bushing CT
of some side of a transformer are both at busbar side, either of them must be reversed by
PCS-Explorer software.
3.5.3.2 Fault Detector
The criterion of fault detector of winding differential protection is as follows. The pickup of this fault
detector will enable winding differential protection of the corresponding side.
wd
I
[87W.I_Biased]
Equation 3.5-1
Where:
wd
I
is winding differential current.
[87W.I_Biased] is the pickup setting of winding differential protection.
3.5.3.3 Amplitude Compensation
If CTs used for winding differential protection have differential primary rated value, then the current
compensation is carried out in the program automatically with parameters input. Following gives
the criteria of calculating correction coefficient.
wb
n
n
wph
K
I
I
K
max
_
1
1
and
)
4
,
min(
min
_
1
max
_
1
n
n
wb
I
I
K
Equation 3.5-2
Where:
wph
K
is the correction coefficient of the calculated CT input.
n
I
1
is the primary value of CT at calculated CT input.
min
_
1
n
I
is the minimum value among primary values of all CTs for winding differential protection.
max
_
1
n
I
is the maximum value among primary values of all CTs for winding differential protection.
This calculation method is to take the minimum CT primary rating of all calculated CT inputs as the
reference. If the multiple of the maximum CT primary ratio to the minimum CT primary rating is
greater than 2.95, then reference shall be taken as 2.95 and others shall be calculated
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 ...