Large phase modifier start grid-connected control method

Abstract

The invention provides a large phase modifier start grid-connected control method, belongs to the technical field of motor controls. The method targets the problems that the large phase modifier when started is dragged by a SFC to a 105% rated speed then gets into the running down state, and boosted grid causes frequency difference and phase angle difference uncontrollable issues, and proposes a control strategy for controlling the SFC removal angle and excitation system at reclosing time, to maximally reduce phase modifier grid-connected impact on the device body and the system. The method can effectively solve the problem that under the condition of unit turning down, the switch of phase modifier start excitation and the self-shunt excitation exciting mode cause grid connecting process to be uncontrollable, the controllability of poor frequency and poor phase angle at grid connection is improved while success rate is ensured, and the impact problem caused by phase modifier grid connection is greatly reduced, the security stability and grid success rate of large phase modifier are improved, the method has significances on the security, efficiency and reliability of running large phase modifier.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method for controlling the start-up and grid-connection of large-scale regulators. Background technique [0002] In high-voltage direct current, especially UHV direct current transmission, whether it is rectification or inverter operation, the converter consumes a large amount of reactive power. In order to ensure the safe and reliable operation of the converter, it is necessary to ensure the supply of reactive power. Insufficient or excess reactive power will directly cause the instability of the AC voltage, which may endanger the safe and stable operation of the entire AC and DC system. Therefore, the flexible, controllable, and fast-response dynamic reactive power adjustment method is of great significance to UHVDC transmission. [0003] As a reactive power generating device, large-scale condensers have unique advantages in improving the short-circuit ratio of the AC ...

AI Technical Summary

Problems solved by technology

[0005] This start-up grid-connection control method mainly relies on the energy stored in the rotating state of the condenser to provide power for boosting grid-connection. There are certain uncertainties and potential safety hazards in the process of starting the excitation and switching from the self-shunt excitation system to the grid.

Factors such as the time when the SFC is disconnected and the time when the self-shunt excitation system is put into operation will have a certain impact on the phase difference and frequency difference when the grid is connected, which in turn will affect the success rate of the grid connection and the impact on the generator and the power grid. Level

This start-up control method has no similar engineering case experience for reference

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