3
Operation
Theory
PCS-978 Transformer Relay
3-128
Date: 2013-01-16
P
set
T
C
)
I
I
(
K
t(I)
1
Equation 3.13-2
Where:
set
I
is residual current setting [x.50/51G4.3I0_Set].
p
T
is time multiplier setting [x.50/51G4.TMS].
K
, C is constants.
is a constant.
I
is actual value of measured current from the neutral CT or calculated residual current.
The user can select the operating characteristic from various inverse-time characteristic curves by
setting [x.50/51G4.Opt_Curve], and parameters of available characteristics for selection are
shown in the following table.
Table 3.13-1 Inverse-time curve parameters of stage 4 ground overcurrent protection
x.50/51G4.Opt_Curve
Time Characteristic
K
α
C
0
Definite time
1
IEC Normal inverse
0.14
0.02
0
2
IEC Very inverse
13.5
1.0
0
3
IEC Extremely inverse
80.0
2.0
0
4
IEC Short-time inverse
0.05
0.04
0
5
IEC Long-time inverse
120.0
1.0
0
6
ANSI Extremely inverse
28.2
2.0
0.1217
7
ANSI Very inverse
19.61
2.0
0.491
8
ANSI Inverse
0.0086 0.02
0.0185
9
ANSI Moderately inverse
0.0515 0.02
0.114
10
ANSI Long-time extremely inverse
64.07
2.0
0.25
11
ANSI Long-time very inverse
28.55
2.0
0.712
12
ANSI Long-time inverse
0.086
0.02
0.185
13
Programmable User-defined
If all available curves do not comply with user application, user may configure setting
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 ...