Overhead flexible direct current power grid fault detection method based on current limiting reactor voltage difference

Abstract

The invention discloses an overhead flexible direct current power grid fault detection method based on current limiting reactor voltage difference. The overhead flexible direct current power grid fault detection method based on the current limiting reactor voltage difference comprises the steps that (1) direct voltage change rates of each of direct current lines in a power grid are continuously monitored, and when the direct voltage change rates are greater than a preset first threshold value, turning into a step (4) is carried out; (2) at one ends of the direct current lines, voltage time products of positive pole current limiting reactors and negative pole current limiting reactors within a target time period are correspondingly obtained and specific values are determined so as to carryout fault pole selection; (3) the sum of the voltage time products of the positive pole current limiting reactors and the negative pole current limiting reactors is obtained, and a second threshold value corresponding to a fault type is obtained, if the sum of the voltage time products is greater than the second threshold value, an occurred fault is determined as a fault inside a zone; if not, theoccurred fault is determined as a fault outside the zone or no fault; and (4) at the two ends of the direct current lines, the step(2)-step(3) are correspondingly carried out to achieve the fault detection. The overhead flexible direct current power grid fault detection method based on the current limiting reactor voltage difference has a high tolerating transition resistance capacity and a highcapacity of resisting disturbance, and can identify various fault types.

Description

technical field [0001] The invention belongs to the field of flexible DC power grids, and more specifically relates to a fault detection method for overhead flexible DC power grids based on voltage differences of current-limiting reactors. Background technique [0002] The DC transmission technology based on Modular Multilevel Converter (MMC) is widely used in new energy power generation, There are broad application scenarios in asynchronous interconnection, urban power grid capacity expansion, power supply to passive systems, and connection to weak AC power grids. In order to further improve the operation flexibility and power supply reliability, the multi-terminal flexible DC grid based on MMC has become one of the development trends of the future smart grid. [0003] Considering the transmission distance, voltage level and cost, overhead line transmission is one of the main ways of large-scale power transmission. The working environment of overhead lines is harsh, and t...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the defects and improvement needs of the prior art, the present invention provides a fault detection method for overhead flexible DC power grids based on the voltage difference of current-limiting reactors, aiming to solve the problem that the existing fault detection methods for flexible DC grids cannot simultaneously withstand transition Problems with resistance, immunity to interference, and identifying single-pole faults

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