38
6
F
2
S
0
7
8
9
2.11 Characteristics of Measuring Elements
2.11.1 Percentage Current Differential Element DIF
The segregated-phase current differential element DIF has dual percentage restraining
characteristics. Figure 2.11.1 shows the characteristics of DF1 and DF2 on the differential
current (I
d
) and restraining current (I
r
) plane. I
d
is a vector summation of phase current of all
windings and I
r
is a scalar summation of phase current of all windings.
I
d
DF2
DF1
ik
kp
I
r
I
d
= 2I
r
(one-end infeed)
Figure 2.11.1 Current Differential Element
Characteristic DF1 is expressed by the following equation:
I
d
p1
I
r
(1
p1
/2)ik
where,
p1
: slope of DF1
ik : minimum operating current
Id and Ir are defined as follows for a three-winding transformer.
I
d
= |kct1
I
1
+ kct2
I
2
+ kct3
I
3
|
I
r
=(kct1
|I
1
|+ kct2
|I
2
|+ kct3
|I
3
|)/2
where,
kct1 ,kct2 ,kct3
: CT ratio matching settings of primary, secondary and tertiary winding
I
1
,I
2
,I
3
: currents of primary, secondary and tertiary winding
This characteristic has weaker restraint in the small current region and ensures sensitivity to low
level faults.
Characteristic DF2 is expressed by the following equation:
I
d
p2
I
r
(p1
p2
)kp
(1
p1
/2)ik
where,
p2 : slope of DF2
kp : break point of DF1 characteristic
This characteristic has stronger restraint in the large current region and ensures stability against
Содержание GRT100 Series
Страница 55: ... 54 6 F 2 S 0 7 8 9 TRANSFORMER PROTECTION GRT100 Operation keys 101B 21 11 Figure 3 1 9 Front Panel ...
Страница 142: ... 141 6 F 2 S 0 7 8 9 Appendix A Block Diagram ...
Страница 144: ... 143 6 F 2 S 0 7 8 9 Appendix B Signal List ...
Страница 159: ... 158 6 F 2 S 0 7 8 9 ...
Страница 160: ... 159 6 F 2 S 0 7 8 9 Appendix C Variable Timer List ...
Страница 162: ... 161 6 F 2 S 0 7 8 9 Appendix D Binary Output Default Setting List ...
Страница 165: ... 164 6 F 2 S 0 7 8 9 ...
Страница 166: ... 165 6 F 2 S 0 7 8 9 Appendix E Details of Relay Menu and LCD and Button Operation ...
Страница 174: ... 173 6 F 2 S 0 7 8 9 Appendix F Case Outline Flush Mount Type Rack Mount Type ...
Страница 179: ... 178 6 F 2 S 0 7 8 9 ...
Страница 180: ... 179 6 F 2 S 0 7 8 9 Appendix G External Connections ...
Страница 185: ... 184 6 F 2 S 0 7 8 9 ...
Страница 200: ... 199 6 F 2 S 0 7 8 9 ...
Страница 201: ... 200 6 F 2 S 0 7 8 9 Appendix J Return Repair Form ...
Страница 205: ... 204 6 F 2 S 0 7 8 9 Customer Name Company Name Address Telephone No Facsimile No Signature ...
Страница 206: ... 205 6 F 2 S 0 7 8 9 ...
Страница 207: ... 206 6 F 2 S 0 7 8 9 Appendix K Technical Data ...
Страница 220: ... 219 6 F 2 S 0 7 8 9 ...
Страница 221: ... 220 6 F 2 S 0 7 8 9 Appendix M Symbols Used in Scheme Logic ...
Страница 224: ... 223 6 F 2 S 0 7 8 9 ...
Страница 225: ... 224 6 F 2 S 0 7 8 9 Appendix N Implementation of Thermal Model to IEC60255 8 ...
Страница 228: ... 227 6 F 2 S 0 7 8 9 ...
Страница 229: ... 228 6 F 2 S 0 7 8 9 Appendix O IEC60870 5 103 Interoperability and Troubleshooting ...
Страница 241: ... 240 6 F 2 S 0 7 8 9 Appendix P Modbus Interoperability ...
Страница 255: ... 254 6 F 2 S 0 7 8 9 ...
Страница 256: ... 255 6 F 2 S 0 7 8 9 Appendix Q Inverse Time Characteristics ...
Страница 259: ... 258 6 F 2 S 0 7 8 9 ...
Страница 260: ... 259 6 F 2 S 0 7 8 9 Appendix R Failed Module Tracing and Replacement ...
Страница 266: ... 265 6 F 2 S 0 7 8 9 Appendix S Ordering ...
Страница 269: ... 268 6 F 2 S 0 7 8 9 3 1 Oct 2 2017 Republished under spin off company ...
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