3
Operation
Theory
PCS-978 Transformer Relay
3-92
Date: 2013-01-16
3.8.5 Logic
3.8.5.1 Logic of Underfrequency Protection
&
Flg_En81U
SIG
[81U.En1]
SIG
[81U.En2]
SIG
[81U.Blk]
50ms 0ms
[81U.UF1.t_Op] 0ms
[81U.UF1.Op]
[81U.UF2.t_Op] 0ms
[81U.UF2.Op]
[81U.UF3.t_Op] 0ms
[81U.UF3.Op]
[81U.UF4.t_Op] 0ms
[81U.UF4.Op]
SIG
f<[81U.f_Pkp]
SIG
f<[81U.UF1.f_Set]
SIG
f<[81U.UF2.f_Set]
SIG
f<[81U.UF3.f_Set]
SIG
f<[81U.UF4.f_Set]
SIG
Flg_En81U
SIG
Flg_Blk81U
&
&
&
&
&
&
EN
[81U.UF1.En]
SIG
[81U.UF2.En]
EN
[81U.UF3.En]
EN
[81U.UF4.En]
SIG
U1<0.15Un
SIG
f
<
fmin or f
>
fmax
Flg_Blk81U
SET
-df/dt>[81U.df/dt_Blk]
SIG
[x.In_VT]
≥
1
Figure 3.8-1 Logic diagram of underfrequency protection
Where:
fmin and fmax are respectively settings [f_Low_FreqAlm] and [f_High_FreqAlm].
[x.In_VT] is the input signal indicating that VT of x side in service. (x represents some side, such
as HVS, MVS, etc.). The signal can be configured as a binary input according to user
requirements, and if the binary input is not configured, the default value of the signal is 1.
Flg_En81U is the internal signal to enable underfrequency protection.
Flg_Blk81U is the internal signal to block underfrequency protection.
For underfrequency protection, if following three conditions are met, the protection will be enabled.
(1) Logic
setting [81U.En] is set to “1”.
(2)
Enabling inputs [81U.En1], [81U.En2] are both set to “1”
(3)
Blocking input [81U.Blk] is set to “0”.
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 ...