A DC single-ended fault location system and method based on active detection

Abstract

The invention discloses a DC single-ended fault positioning system and a DC single-ended fault positioning method based on active detection. The DC single-ended fault positioning method comprises thesteps of: determining a fault ride-through strategy of a converter, and enabling an MMC system to detect the change of a direct voltage or a direct current when a DC line fails; injecting an active detection signal, and discriminating faults through active fault control and disturbance application; filtering fault information, and processing the fault information by considering the coupling influence between positive and negative direct-current lines; and realizing fault positioning by using a least square method and a data sliding window method according to the voltage and current informationof a set point. The DC single-ended fault positioning system and the DC single-ended fault positioning method can precisely identify the fault region, are suitable for long DC lines, are not affectedby transition resistance, have low requirements for the sampling rate, and have relatively high reliability and precision in fault positioning.

Description

technical field [0001] The invention belongs to the technical field of power system fault location, and in particular relates to a DC single-ended fault location system and method based on active detection. Background technique [0002] Considering that the recovery and restart process of the DC power grid based on the half-bridge converter is cumbersome, it makes the power recovery time longer and may lead to the loss of stability of the AC system. In addition, the breaking capacity and input cost of the DC circuit breaker are relatively large. On the other hand, considering the high controllability of the full-bridge sub-modules, the sub-modules can still maintain the control state during the fault and realize fault ride-through. However, the number of half-bridge sub-modules is half of that of the full bridge, which has economic advantages. Therefore, the overhead line system based on hybrid MMC direct current transmission has gradually become a future development trend,...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a DC single-ended fault location system and method based on active detection to overcome the inability of traditional traveling wave fault location and fault analysis and location methods in DC lines. At the same time, it satisfies the limitations of reliability and positioning accuracy, requires low sampling rate, is not affected by transition resistance, can be applied to long lines, and is not affected by line frequency variable parameters. At the same time, it takes into account the reliability and positioning accuracy of fault location.

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