Method and device for reducing bus voltage fluctuation during AC filter bank switching

Abstract

The invention discloses a method for reducing bus voltage fluctuations in the switching process of an AC filter bank. After the switch group is actually put into or cut off, the effective value of the AC bus voltage of the DC converter station is measured in real time, so as to calculate the change rate of the effective value of the AC bus voltage in real time, and generate a corresponding additional reactive power command; the additional The reactive power command is added to the original reactive power command of the STATCOM coordination controller to obtain a target reactive power command, and reactive power compensation is performed according to the target reactive power command. The implementation of the embodiments of the present invention can effectively reduce the fluctuation range of the AC bus voltage of the converter station during the switching process of the AC filter bank, thereby effectively suppressing the voltage stress problem of the AC bus bar during the switching process of the AC filter bank.

Description

technical field [0001] The invention relates to the field of direct current transmission, in particular to a method and a device for reducing bus voltage fluctuations during the switching process of an AC filter bank. Background technique [0002] HVDC transmission has the advantages of energy saving and low line cost, and plays an important role in long-distance and high-power transmission. At present, the DC transmission system based on the thyristor converter valve is the most widely used, which is called the conventional DC transmission system. In order to compensate the large amount of reactive power consumed by the characteristics of the thyristor converter valve itself, and to suppress the characteristic harmonics injected into the AC grid, the AC side of the conventional DC power transmission converter station will be equipped with an AC power converter with a DC rated capacity of about 40% to 60%. filter bank. The AC filter bank is composed of several AC filter gr...

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Problems solved by technology

However, in the process of implementing the present invention, the inventor found that the prior art has at least the following problems: before the AC filter bank performs switching-in or cutting-off action, the reactive power output of the STATCOM is pre-adjusted, which will change the reactive power output of the STATCOM in advance, and This part of the pre-adjusted reactive power will change the steady-state voltage level of the converter station before the filter bank is put in or cut off, which may make the steady-state voltage level of the converter station before the filter bank put in or cut off too high or too low ; and in the method of changing the PI controller parameters of STATCOM to improve the transient voltage fluctuation of the AC filter switching process, because the PI parameters of STATCOM are closely related to its various performances, in actual engineering applications, changing the design of STATCOM The setting value is not conducive to ensuring the safety and reliability of the power system

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