6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 26 -
𝑍
1
=
𝑉
𝑏
− 𝑉
𝑐
𝐼
𝑏
− 𝐼
𝑐
(2.1-6)
As shown above, the positive-sequence impedance is used when determining settings for
phase faults.
Figure 2.1-1 Phase-to-phase fault
(ii)
Single-phase-earth fault
Figure 2.1-2 shows the power system in the event of a single-phase-earth fault. It is very
difficult to measure precisely the distance to the fault point for a single-phase-earth fault. This
is because the impedance of the zero-sequence circuit including the earth return is generally
different from the positive-sequence impedance. Therefore, the faulted phase voltage is not
simply proportional to the faulted phase current.
Figure 2.1-2 Single-phase-earth fault
It is necessary to analyze the impedance seen by the relay in the event of a single-phase-
earth fault according to the method of symmetrical components. Figure 2.1-3 shows an
equivalent circuit for a single-phase-earth fault based on the method of symmetrical
components. If we define the positive-sequence, negative-sequence and zero-sequence voltages
as being V1F, V2F and V0F, then the voltage at the relaying point of each symmetrical circuit
will be given by the following equations based upon the assumption that the positive-sequence
Zs
VF
VF
Ib
Vc
Ic
Zm
Va
Vb
ZS
VaF
Ib
Vc
Ic
Va
Vb
ZG
Ia
Содержание GR 200 Series
Страница 1047: ...6F2S1915 0 46 GRZ200 Soft 031 032 1026 Figure 8 3 4 Screen shot from GR TIEMS ...
Страница 1354: ...6F2S1915 0 46 GRZ200 Soft 031 032 1333 Appendix 1 Signal list for common function ...
Страница 1369: ...6F2S1915 0 46 GRZ200 Soft 031 032 1348 Unit mm Panel cut out for 1 2 case size Figure 2 2 3 Panel cutout figure 1 2 size case ...
Страница 1410: ...6F2S1915 0 46 GRZ200 Soft 031 032 1389 This page is intentionally blank ...
Страница 1480: ...6F2S1915 0 46 GRZ200 Soft 031 032 1459 Appendix 6 Ordering ...
Страница 1497: ...6F2S1915 0 46 GRZ200 Soft 031 032 1476 Appendix 7 Technical data ...
Страница 1518: ...6F2S1915 0 46 GRZ200 Soft 031 032 1497 Appendix 8 Manufacture setting ...
Страница 1520: ...6F2S1915 0 46 GRZ200 Soft 031 032 1499 Appendix 9 Matrix between VCT terminals and relay applications ...
Страница 1523: ...6F2S1915 0 46 GRZ200 Soft 031 032 1502 Appendix 10 CT requirement ...
Страница 1531: ...6F2S1915 0 46 GRZ200 Soft 031 032 1510 Appendix 12 Engineering exercise ...
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