Excitation control method of large-size phase modifier during starting and grid-connected process

Abstract

The invention discloses an excitation control method of a large-size phase modifier during the starting and grid-connected process. A self excitation system and a separate excitation system are independent at an AC side and a rectification unit, are connected in parallel at a DC side and share a group of de-excitation and overvoltage protection device, the switching time of the two excitation systems is short, no disturbance is generated during the switching process, a boost mode of a phase modifier end employs two-segment boosting, inversion and zero-starting boosting are not needed, and an excitation current is rapidly and smoothly transferred to the other excitation system from one of the excitation systems. By coordinated control of a corresponding excitation regulator, the problem ofrapid switching of the two excitation systems during the running down process of the large-size phase modifier is solved, the disturbance of the two excitation systems during the switching process issuppressed, the complete protection function is achieved, the impact caused by voltage difference during grid connection of the large-size phase modifier is reduced, and the excitation control methodhas the important significance to the safe, efficient and reliable running of the large-size phase modifier.

Description

technical field [0001] The invention relates to an excitation control method during the start-up and grid-connection process of a large-scale regulator, and belongs to the technical field of motor control. Background technique [0002] At present, dynamic reactive power compensation is crucial to ensure grid voltage stability and safe operation of UHV DC. The condenser has the advantages of strong dynamic reactive power support capability, stable and reliable operation, and can effectively solve the problems of insufficient dynamic reactive power of the receiving-end power grid and insufficient short-circuit capacity support of the weak sending-end power grid. The subtransient characteristics of the condenser can effectively suppress the probability of commutation failure in the DC system; the transient characteristics help the system voltage to quickly return to the normal level after a serious fault. [0003] According to the strategic plan of the State Grid, multiple UHV...

AI Technical Summary

Problems solved by technology

If the excitation is switched on the AC side, the inverter needs to be shut down in the other excitation mode first, and then the excitation boost is re-started in the self-shunt excitation mode, which takes a long time and cannot meet the extremely high time requirements of idling grid connection.

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