| 摘要 |
PROBLEM TO BE SOLVED: To eliminate overload by preventing generation of a cross current when reserve machine is turned on. SOLUTION: A bus voltage regulator 47a determines parallel operation when each on-load tap changing transformer is connected to the same secondary bus by open/close state of a circuit breaker LS on the secondary of each on-load tap changing transformer and a bus tie circuit breaker, and performs tap change of respective on-load tap changing transformers operating in parallel in response to a command from a voltage regulation relay 48. At the same time, when an auxiliary relay X2 in the bus voltage regulator 47a is excited, and an electromagnetic contactor 54 connected with a circuit breaker 44 on the secondary of a reserve on-load tap changing transformer 21 interrupted from the secondary bus is turned on while an electromagnetic contactor 55 is turned off as if the circuit breaker 44 is turned on, a decision is made that the reserve on-load tap changing transformer 21 is operating in parallel with other on-load tap changing transformer, and tap change is performed simultaneously with other on-load tap changing transformer. COPYRIGHT: (C)2009,JPO&INPIT
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