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发表于 2009-12-27 13:43:40
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本帖最后由 楚大少 于 2009-12-28 18:24 编辑
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5 m. H) J. s# RWhen an unbalanced fault happens in the system, the relays will see zero sequence components or negative sequence components or both of them. This will depend on the type of the fault. And it will also depend on whether the system is grounded or not.8 O& N( W% k) }& q# ~/ J) @' i
; r% p H& f6 W/ GIn normal power system, there will be some zero & negative sequence components even when the system is operating correctly. So when we are setting the relays, we should consider the worst case, in which the relays will see the largest zero or negative sequence components. And then the setting should be above the worst case. However, this is also changing as the communication among the relays are becoming more common.6 E0 c [$ G; l# u3 @
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I hope this is helpful;-) |
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