Judgment method and device for simultaneous commutation failure of high and low end current converters

Abstract

The invention provides a judgment method and device for simultaneous commutation failure of high and low end current converters. Firstly the interacting factor of the low end current converter for thehigh end current converter and the interacting factor of the high end current converter for the low end current converter are calculated, then the critical interacting factor of the low end current converter for the high end current converter and the critical interacting factor of the high end current converter for the low end current converter are calculated, and finally the situation of simultaneous commutation failure of the high and low end current converters is judged so that judgment of the situation of simultaneous commutation failure of the high and low end current converters can be realized. According to the technical scheme, the interaction effect of the high end current converter and the low end current converter in the DC power transmission system is considered so that misjudgment of the situation of simultaneous commutation failure of the high end current converter and the low end current converter can be avoided and the judgment result is relatively accurate.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a method and device for judging the failure of simultaneous phase commutation of high-end and low-end converters. Background technique [0002] UHV DC transmission system (thyristor-based UHV DC transmission system) is connected to the AC grid in a layered manner, which has the advantages of guiding the rational distribution of power flow and improving the voltage support capability, so it is widely used in newly built large-capacity UHV DC transmission systems. application. Under the new access mode of the UHVDC transmission system connected to the AC grid in a layered manner, large-scale electric energy will be injected into the AC grid of different voltage levels in the same area. How to accurately analyze the acceptance capacity of the AC grid is an urgent need study in depth. There is a big difference between the thyristor-based UHVDC transmission system connecting t...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the inaccurate judgment of whether the high-end converter and the low-end converter have commutation failures at the same time due to the lack of consideration of the mutual influence of the high-end converter and the low-end converter in the DC transmission system in the above-mentioned prior art The present invention provides a method and device for judging the simultaneous commutation failure of high-end and low-end converters. First, calculate the interaction factor of the low-end converter for the high-end The interaction factor of the inverter, and then calculate the critical interaction factor of the low-end converter to the high-end converter and the critical interaction factor of the high-end converter to the low-end converter, and finally according to the low-end converter to the high-end converter According to the interaction factor of the high-end converter and the critical interaction factor of the low-end converter to the high-end converter or according to the interaction factor of the high-end converter to the low-end converter and the critical The action factor judges whether the commutation failure of the high-end and low-end converters occurs at the same time, and realizes the judgment of the simultaneous commutation failure of the high-end and low-end converters

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