Method and device for reducing bus voltage fluctuation in switching process of AC filter bank

Abstract

The invention discloses a method for reducing bus voltage fluctuation in the switching process of an AC filter bank. The method comprises the steps: detecting whether a DC converter station control system sends out an input control signal or a cut-off control signal of the AC filter bank or not in real time; measuring the effective value of the AC bus voltage of the DC converter station in real time after the AC filter bank is truly switched on or switched off 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 instruction; adding the additional reactive power instruction to an original reactive power instruction of a STATCOM coordination controller to obtain a target reactive power instruction,and performing reactive power compensation according to the target reactive power instruction. By implementing the embodiment of the invention, the fluctuation amplitude of the AC bus voltage of theconverter station in the switching process of the AC filter bank can be effectively reduced, so that the voltage stress problem of the AC bus in the switching process of the AC filter bank is effectively inhibited.

Description

Technical field [0001] The invention relates to the field of direct current transmission, and in particular to a method and 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 it occupies an important position in long-distance, high-power transmission. At present, the DC transmission system based on the thyristor converter valve is the most widely used and is called the conventional DC transmission system. In order to compensate for the large amount of reactive power consumed by the characteristics of the thyristor converter valve, and to suppress the characteristic harmonics injected into the AC grid, the AC side of the conventional DC transmission converter station will be equipped with AC with a DC rated capacity of about 40% to 60% Filter bank. The AC filter group is composed of several AC filter groups, and the switching of ...

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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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