题目内容

After the generator was overhauled, when the parallel operation was performed for the first time, it was found that the synchronizing lamps are not bright and dark at the same time, which indicated ( ).

A. Standby generator’s rotating speed is too high
B. Standby generator’s rotating speed is too low
C. phase sequence is not the same
D. leading phase of standby generator

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When synchronizing operation for synchronous generator, if other requirements all meet,only have phase difference, as phase difference is ( ) , there have the minimal surge current .

A. 0°
B. 45°
C. 90°
D. 180°

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For manually quasi-synchronizing method ( the nonimal frequency is 50 Hz ), the allowable differences of voltage, frequency and primary phase angle is ( ).

A. △U≤±6%UN、△f≤±0.5Hz、△δ≤±30°
B. △U≤±10%UN、△f≤±0.5Hz、△δ≤±15°
C. △U≤±10%UN、△f≤±2Hz、△δ≤±30°
D. △U≤±10%UN、△f≤±2Hz、△δ≤±15°

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During parallel operation, unless the disassemble inspection is performed, otherwise we don’t have to check whether ( ) or not.

A. the voltage effective value is the same
B. frequency is the same
C. the phase angle is the same
D. the phase sequence is the same

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When two synchronous generators parallel running,there must have ( ).

A. equal voltage/equal current/ equal frequency
B. equal voltage/ equal frequency
C. equal current/ equal frequency
D. equal active power/ equal reactive power

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After the generator was overhauled, when the parallel operation was performed for the first time, it was found that the synchronizing lamps are not bright and dark at the same time, which indicated ( ).

A. Standby generator’s rotating speed is too high B. Standby generator’s rotating speed is too low C. phase sequence is not the same D. leading phase of standby generator

When synchronizing operation for synchronous generator, if other requirements all meet,only have phase difference, as phase difference is ( ) , there have the minimal surge current .

For manually quasi-synchronizing method ( the nonimal frequency is 50 Hz ), the allowable differences of voltage, frequency and primary phase angle is ( ).

During parallel operation, unless the disassemble inspection is performed, otherwise we don’t have to check whether ( ) or not.

When two synchronous generators parallel running,there must have ( ).

A. Standby generator’s rotating speed is too high
B. Standby generator’s rotating speed is too low
C. phase sequence is not the same
D. leading phase of standby generator