Synchronous grid connected method and system

Abstract

The invention provides a synchronous grid connected method and system; the method comprises the following steps: a speed adjusting device measures the frequency of a to-be-connected motor, and determines whether the frequency of the to-be-connected motor satisfies a first grid connected condition or not; if not, the speed adjusting device adjusts the rotating speed of the to-be-connected motor until the frequency of the to-be-connected motor satisfies the first grid connected condition; an excitation adjusting device measures an exciting current of the to-be-connected motor, and determines whether the exciting current of the to-be-connected motor satisfies a second grid connected condition or not; if not, the excitation adjusting device adjusts the exciting current of the to-be-connected motor until the exciting current of the to-be-connected motor satisfies the second grid connected condition; when the first and second grid connected conditions are met in the same time, a synchronizing device outputs a breaker closing order, thus preventing overstrike or under-strike, accelerating the adjusting process, and greatly improving the adjusting precision.

Description

technical field [0001] The present invention relates to the technical field of power grid parallel connection, in particular, to a synchronous grid connection method and system. Background technique [0002] The power supply of modern power system is generally composed of parallel operation of synchronous motors in power plants distributed in different regions, so as to economically and rationally use different types of energy, including: water energy, wind energy, nuclear energy, coal, natural gas and other natural resources. The interconnection between the synchronous motor and the grid is completed through the circuit breaker under the control of the synchronous device, so the safe and reliable operation of the synchronous device is the prerequisite for the synchronous motor to be connected to the grid. In addition, when two different power grid systems are interconnected through AC, a synchronization device is also required to optimize the interconnection time and determ...

AI Technical Summary

Problems solved by technology

The synchronous device in the prior art needs to issue adjustment instructions to the excitation adjustment device and the speed control device. The adjustment instructions are superimposed on the set values ​​of the respective devices, and the corresponding devices respond again, which may cause overshoot or undershoot, resulting in adjustment There is a delay in the process, and the grid connection is delayed in the same period, and the adjustment accuracy is not high

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