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17
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6 F 2 S 0 8 4 6
2.2 Principle of Distance Measurement
2.2.1 Phase
Fault
The phase-fault distance relay measures the impedance from the relay to the fault point using a
delta voltage and current. The positive-sequence impedance is used as the line impedance. The
principle is described below.
Figure 2.2.1.1 shows the circuit in the event of a two-phase fault. Suppose that the impedance from
the relay to the fault is the same in both phase B and phase C, and that the self impedance is Zs and
the mutual impedance between phases is Zm. If the voltages and currents of phase B and phase C
are Vb, Vc, Ib and Ic and the fault point voltage is VF, then Vb and Vc are given by the following
equations.
Vb = Zs
×
Ib + Zm
×
Ic + VF....................... (2-1)
Vc = Zs
×
Ic + Zm
×
Ib + VF....................... (2-2)
From equations (2-1) and (2-2), the following equation is obtained.
Vb
−
Vc = (Zs
−
Zm)
×
(Ib
−
Ic) ......................... (2-3)
where,
Zs: Self
impedance
Zm: Mutual impedance
Since the effect of the phase A current is small and is almost canceled when introducing equation
(2-3), it is omitted in equations (2-1) and (2-2).
When each phase of the line is symmetric to the other, the positive-sequence and zero-sequence
impedance Z1 and Z0 according to the method of symmetrical components are defined by the
following equations, using self impedance Zs and mutual impedance Zm:
Z1 = Zs
−
Zm ............................................... (2-4)
Z0 = Zs + 2Zm ............................................. (2-5)
where,
Z1: Positive-sequence impedance
Z0: Zero-sequence impedance
Equation (2-3) can be rewritten as follows:
Z1 = (Vb
−
Vc)/(Ib
−
Ic) .............................. (2-6)
As shown above, the positive-sequence impedance is used for the phase fault relay setting.
Figure 2.2.1.1 Two-Phase Fault
Va
Zs
VF
VF
Vb
ib
Vc
ic
Zm
Содержание GRZ100 B Series
Страница 264: ... 263 6 F 2 S 0 8 4 6 Appendix A Block Diagram ...
Страница 271: ... 270 6 F 2 S 0 8 4 6 ...
Страница 272: ... 271 6 F 2 S 0 8 4 6 Appendix B Signal List ...
Страница 307: ... 306 6 F 2 S 0 8 4 6 ...
Страница 308: ... 307 6 F 2 S 0 8 4 6 Appendix C Variable Timer List ...
Страница 310: ... 309 6 F 2 S 0 8 4 6 Appendix D Binary Input Output Default Setting List ...
Страница 321: ... 320 6 F 2 S 0 8 4 6 ...
Страница 322: ... 321 6 F 2 S 0 8 4 6 Appendix E Details of Relay Menu and LCD Button Operation ...
Страница 331: ... 330 6 F 2 S 0 8 4 6 ...
Страница 340: ... 339 6 F 2 S 0 8 4 6 Appendix G Typical External Connections ...
Страница 377: ... 376 6 F 2 S 0 8 4 6 ...
Страница 384: ... 383 6 F 2 S 0 8 4 6 Appendix J Return Repair Form ...
Страница 388: ... 387 6 F 2 S 0 8 4 6 Customer Name Company Name Address Telephone No Facsimile No Signature ...
Страница 389: ... 388 6 F 2 S 0 8 4 6 ...
Страница 390: ... 389 6 F 2 S 0 8 4 6 Appendix K Technical Data ...
Страница 401: ... 400 6 F 2 S 0 8 4 6 ...
Страница 402: ... 401 6 F 2 S 0 8 4 6 Appendix L Symbols Used in Scheme Logic ...
Страница 405: ... 404 6 F 2 S 0 8 4 6 ...
Страница 406: ... 405 6 F 2 S 0 8 4 6 Appendix M Example of Setting Calculation ...
Страница 417: ... 416 6 F 2 S 0 8 4 6 ...
Страница 418: ... 417 6 F 2 S 0 8 4 6 Appendix N IEC60870 5 103 Interoperability and Troubleshooting ...
Страница 430: ... 429 6 F 2 S 0 8 4 6 Appendix O Programmable Reset Characteristics and Implementation of Thermal Model to IEC60255 8 ...
Страница 434: ... 433 6 F 2 S 0 8 4 6 Appendix P Inverse Time Characteristics ...
Страница 437: ... 436 6 F 2 S 0 8 4 6 ...
Страница 438: ... 437 6 F 2 S 0 8 4 6 Appendix Q Failed Module Tracing and Replacement ...
Страница 444: ... 443 6 F 2 S 0 8 4 6 Appendix R Ordering ...
Страница 447: ......