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How to realize parallel power generation for two generators?

How to realize parallel power generation for two generators


Conditions for parallel operation of generators


1. The voltage rms value Uf of the generator to be equal to or nearly equal to the voltage rms U of the grid, allowing a voltage difference of ± 5% of the rated voltage.


2. The cycle ff of the generator should be equal to the cycle f of the grid, but the difference is allowed to be within ±0.05~0.1 weeks/second.


3. The phase of the generator voltage is the same as the phase of the grid voltage, that is, the phase angle is the same.


4. The phase sequence of the generator voltage must be consistent with the phase sequence of the grid voltage.


5. The waveform of the generator voltage should be consistent with the waveform of the grid voltage.


In summary, when the generators are juxtaposed, the conditions of 1 to 3 items are mainly met, otherwise serious accidents will result.

parallel power generation for generators

Operation when generators are juxtaposed


There are two ways to arrange generators in parallel: quasi-simultaneous parallel method and self-synchronous parallel method.


Quasi-synchronous parallel method is widely used at present. The quasi-simultaneous parallel method is divided into manual, semi-automatic and automatic. Generally, manual or semi-automatic operation methods are adopted.



In order to prevent juxtaposition of different periods, it is not allowed to close in the following three cases:


1. The pointer of the combined three-phase synchronizing watch S is not stable and has a beating phenomenon, and it is not allowed to close.


2. If the pointer of the combined three-phase synchronizing table S is stagnant near the synchronous point, the closing is not allowed.


3. If the pointer of the combined three-phase synchronizing table S rotates too fast, it is not allowed to close.

Operator requirements


The parallel operation of the generator is very important, to a certain extent related to the safety of the entire power plant and the power grid.


Therefore, the operator must be required to have a wealth of field experience and practical work;

It is required that the attention must be highly concentrated during operation, and closely monitor the changes in the meter and tie line;


Seize the opportunity to conduct the parallel operation of the generators steadily and accurately, and ensure that the generators are safely and reliably integrated into the grid.



XIAMEN AOT ELECTRONICS TECHNOLOGY CO.,LTD which can provide full kinds of generator spare parts for engine replacement. Welcome to contact us for more information.


Contact: Ms.Lika (Sales)

Email / Skype:

Phone / Whatsapp/ Wechat: +86 159 8080 8150



Contact: Lika

Phone: 0086-15980808150

Tel: 0086-592-7161550


Add: Unit 1405, 2000 Xiangfu Road, Xiamen City, China

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