For parallel operating generator sets, they can operate stably when the load changes, and their active and reactive power are distributed proportionally to the rated power of each generator set. The parallel operation of generator sets can increase the reliability of power supply, improve the economic efficiency of power station operation, and reduce the capacity of backup units.

Parallel operation of DC units

DC units operating in parallel should be able to operate stably under all loads from no load to full load. When the load changes within the range of 20% to 100% of the total rated power, the power distribution difference should not exceed 12% of the maximum generator rated power and 25% of the minimum generator rated power.

Parallel operation of AC generator sets

AC generator sets operating in parallel should be able to operate stably when the load varies within the range of 20% to 100% of the total rated power according to the rated power factor. The difference in active power distribution should not exceed 15% of the maximum generator rated power and 25% of the minimum generator rated power. The difference in reactive power distribution should not exceed 10% of the maximum generator rated reactive power and 25% of the minimum generator rated reactive power.

Parallel operation test for marine generator set

The experiment involves combining generators that require long-term parallel operation and operating them together according to various specified parallel operation methods to measure the voltage, current, frequency, power, and power factor data of each generator.

This test should be conducted after the single unit test is qualified, and the steady-state speed regulation rate of the parallel operating unit should be adjusted as consistent as possible.

Load the operating unit to 40% of the rated load, with a power factor of 0.8 (lag), adjust the voltage of the unit to be paralleled, with a frequency slightly higher than the operating unit, put it into parallel operation, increase the total load to 75% of the rated load as the basic adjustment point, adjust the speed of the parallel unit, so that the distribution of active and reactive power is basically the same, do not allow the second adjustment after power sharing, and then change the total load in one direction: 75% → 100% → 75% → 50% → 20% → 50% → 75%, keep the total load power factor of 0.8 (lag), calculate the active power distribution difference ∆ P and reactive power distribution difference ∆ Q, and operate for 1h/when the total power is 90%, observe the parallel Stability.

Directly start the asynchronous motor with a capacity of about 25% of the small and medium-sized units in parallel operation under a load condition of 25%~50%, and observe the stability of parallel operation.