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2.6 Autoreclose
2.6.1 Application
Most faults that occur on high voltage or extra-high voltage overhead lines are transient faults
caused by lightning. If a transient fault occurs, the circuit breaker is tripped to isolate the fault, and
then reclosed following a time delay to ensure that the gases caused by the fault arc have
de-ionized. This makes it possible to recover power transmission.
The time between clearing the fault and reclosing the circuit breaker, that is, the dead time, should
be made as short as possible to keep the power system stable. From the viewpoint of de-ionization
of the fault arc, the fault arc is de-ionized more thoroughly as the period of this dead time is
extended. The de-ionization commences when the circuit breakers for all terminals of the line are
tripped. Therefore, the dead time can be set at its minimum level if all terminals of the line are
tripped at the same time.
Autoreclose of the GRZ100 is started by any of the following protections that ensure high-speed
protection of all terminals.
•
command
protection
•
zone 1 extension protection
•
specific zone 1 tripping
The GRZ100 provides two autoreclose systems, single-shot autoreclose and multi-shot
autoreclose.
Single-shot autoreclose
Three types of single-shot autoreclose modes are provided: single-phase autoreclose, three-phase
autoreclose, and single- and three-phase autoreclose. An optimal mode is selected form among
"Off (disable)" "SPAR", "TPAR", "SPAR&TPAR", "EXT1P" and "EXT3P" by the autoreclose
mode selection switch [ARC-M] or PLC signals (No.1683 – 1688). The PLC signals have priority
over the switch [ARC-M] setting. In any case, autoreclose is performed only once. If the fault state
still continues after reclosing, three-phases final tripping is activated.
Single-phase autoreclose:
In this mode, only the faulty phase is tripped, and then reclosed if a single-phase earth fault occurs.
In the case of a multi-phase fault, three phases are tripped, but reclosing is not made. Since power
can be transmitted through healthy phases even during dead time, this mode is convenient for
maintaining power system stablility. On the other hand, the capacitive coupling effect between the
healthy phase and faulty phase may cause a longer de-ionization time when compared to a
three-phase autoreclose. As a result, a longer dead time is required.
It is essential to correctly determine a faulty phase. The GRZ100 is equipped with an undervoltage
element with current compensation to correctly determine the faulty phase(s).
For single-phase autoreclose, each phase of the circuit breaker must be segregated.
This reclosing mode is simply expressed as "SPAR" in the following descriptions.
Three-phase autoreclose:
In this autoreclose mode, three phases are tripped, and then reclosed regardless of the fault mode,
whether single-phase fault or multi-phase fault. A shorter dead time can be set in this mode when
compared to the single-phase autoreclose. For the three-phase autoreclose, synchronism check and
voltage check between the busbar and the line are required.
This reclosing mode is simply expressed as "TPAR" in the following descriptions.
Содержание GRZ100 B Series
Страница 264: ... 263 6 F 2 S 0 8 4 6 Appendix A Block Diagram ...
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Страница 272: ... 271 6 F 2 S 0 8 4 6 Appendix B Signal List ...
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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 ...
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Страница 322: ... 321 6 F 2 S 0 8 4 6 Appendix E Details of Relay Menu and LCD Button Operation ...
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Страница 340: ... 339 6 F 2 S 0 8 4 6 Appendix G Typical External Connections ...
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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 ...
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Страница 390: ... 389 6 F 2 S 0 8 4 6 Appendix K Technical Data ...
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Страница 402: ... 401 6 F 2 S 0 8 4 6 Appendix L Symbols Used in Scheme Logic ...
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Страница 406: ... 405 6 F 2 S 0 8 4 6 Appendix M Example of Setting Calculation ...
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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 ...
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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 ...
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