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3 Operation Theory
PCS-978 Transformer Relay
3-27
Date: 2013-01-16
3.2.4.1 Logic of Current Differential Protection
SIG
Flg_ConvBiasDiff
SIG
&
&
SIG
SIG
SIG
SET
SIG
SIG
>1.4
&
&
SIG
&
&
&
EN
[87T.En_Biased]
SIG
SIG
SIG
[87T.En1]
[87T.En2]
[87T.Blk]
Flg_Inrush_ConvBiasDiff
EN
[87T.En_Biased]
SIG
SIG
SIG
[87T.En1]
[87T.En2]
[87T.Blk]
Flg_SensBiasDiff
Flg_CTSaturation
Flg_Inrush_SensBiasDiff
Flg_CTS
[87T.En_CTS_Blk]
Flg_OvExc_Hm3/Hm5
*
*
/
f
U
&
&
≥
1
EN
[87T.En_Instant]
SIG
SIG
SIG
[87T.En1]
[87T.En2]
[87T.Blk]
SIG
Idmax>[87T.I_Instant]
&
SIG
FD_BiasDiff
SIG
FD_InstDiff
SIG
FD_BiasDiff
0ms 500ms
0ms 500ms
0ms 500ms
[87T.Op_Instant]
[87T.Op_Biasd]
Figure 3.2-8 Logic diagram of current differential protection
Where:
Idmax is the maximum value of three phase differential currents.
*
*
/
f
U
is the value indicating the degree of overexcitation of transformer.
Flg_ConvBiasDiff is the internal flag indicating that operation criteria of conventional biased
differential protection are satisfied.
Flg_SensBiasDiff is the internal flag indicating that operation criteria of sensitive biased differential
protection are satisfied.
Flg_CTS is the internal flag indicating CT circuit failure is distinguished.
Flg_CTSaturation is the internal flag indicating CT saturated.
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 ...