Two-level flexible direct current power transmission converter fault protection and fault diagnosis method

Abstract

The invention discloses a two-level flexible direct current power transmission converter fault protection and fault diagnosis method. The method provided by the invention is characterized in that a step 1 converter fault protection comprises: a step 101, converter outlet current signal acquisition and processing, a step 102, interruption of working of IGBT devices of a faulted converter, a step 103, the tripping-out of the alternating current system circuit breaker of the convertor station of the faulted converter, a step 104, working of normally functioning converters in a passive compensation state; a step 2 converter fault diagnosis comprises: a step 201, fault signal acquisition, a step 202, preprocessing of fault signals, a step 203, fault characteristic parameter calculation, a step 204, converter fault diagnosis of a converter fault diagnosis module by adopting a layering method. The two-level flexible direct current power transmission converter fault protection and fault diagnosis method is advantageous in that the steps are simple, the realization is convenient, the cost is low, the fault diagnosis identification rate is high, the practicability is strong, the use effect is good, and the popularization and the application are facilitated.

Description

technical field [0001] The invention belongs to the technical field of flexible direct current transmission systems, and in particular relates to a fault protection and fault diagnosis method for a two-level flexible direct current transmission converter. Background technique [0002] Flexible direct current transmission system (VSC-HVDC) is a new type of direct current transmission technology developed in response to the requirements of green power grids and new energy power generation. It has been widely used in many fields such as wind power generation, island power transmission, and ocean power generation. Each bridge arm of the flexible direct current transmission converter needs to be cascaded with several high-power fully-controlled devices, which is the core part of the device. When the voltage source converter fails, each device or component that constitutes the system may be subjected to abnormal stress such as overvoltage, overcurrent, overheating, etc. If it is n...

AI Technical Summary

Problems solved by technology

However, the VSC-HVDC fault diagnosis method based on the two-level voltage source converter proposed in the existing fault diagnosis technology needs to extract the diagnostic signal for a long time. If the voltage source converter has a serious through fault, the fault occurs instantaneously Severe overcurrent phenomenon needs to start the protection strategy to protect the voltage source converter in a short period of time, but the proposed diagnosis method encounters difficulties in extracting fault diagnosis signals, and the fault diagnosis method is difficult to apply to the actual system

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