LCL-HVDC converter circuit

Abstract

The invention relates to an LCL-HVDC three-phase converter circuit. The converter circuit comprises a rectification end and an inversion end converter transformer, a converter valve, a direct current field smoothing reactor LS, current limiting reactors LY and LD of an alternating current field, an inversion side controlled insertion capacitor Cs and a shunt capacitor Cp, a bridge circuit at the rectification end comprises three arms which are connected in parallel, each arm corresponds to one phase of three-phase alternating current, each arm is led out from a silicon controlled rectifier valve group at the rectification end and sequentially comprises a current-limiting reactor LY and the shunt capacitor Cp, the output ends of the current-limiting reactors LYa, LYb and LYc of the three arms which are connected in parallel are connected with one silicon controlled rectifier valve group, the output end of the silicon controlled rectifier valve group is connected with the input end of a direct-current field smoothing reactor LS, and the output end of the direct-current field smoothing reactor LS is connected with a bridge circuit at the inversion end. Ultra-high electromagnetic noise of the converter transformer can be effectively reduced, commutation failure is eliminated, and an alternating-current side filter and parallel capacitance compensation are cancelled.

Description

technical field [0001] The invention relates to an LCL-HVDC three-phase commutation circuit, which belongs to the technical field of electric power transmission. Background technique [0002] At present, there are certain hidden dangers and technical problems that need to be solved urgently in the high-voltage direct current transmission system, such as the problem of harmonics and reactive power of the converter, the commutation failure at the inverter end of the system, and the ultra-high electromagnetic noise of the converter transformer. Especially when the AC power grid is faulty at the inverter end of the system, the converter is prone to commutation failure, and even causes the converter to be blocked, which is one of the most typical faults in HVDC transmission projects. At the same time, the ultra-high noise of the converter transformer itself has far exceeded that of the power transformer, which will have a negative impact on the converter transformer itself, the o...

AI Technical Summary

Problems solved by technology

Although this technology has a certain effect on environmental noise reduction, it is expensive, occupies a large area, and is not conducive to the heat dissipation of the converter transformer. Treatment measures can only face the burning and damage of the entire converter transformer

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