Self-adaptive reclosing method for single-phase earth fault in bipolar direct-current power grid

A single-phase ground fault, direct current technology, applied to electrical components, circuit devices, emergency protection circuit devices, etc., can solve problems such as secondary overcurrent of DC lines, large AC short-circuit current, secondary damage to MMC, etc., to avoid secondary impact, strong resistance to transition resistance, and the effect of reducing design difficulty and cost
CN112072619AInactive Publication Date: 2020-12-11TIANJIN UNIV
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Applications(China)
Current Assignee / Owner
TIANJIN UNIV
Publication Date
2020-12-11
Estimated Expiration
Not applicable Β· inactive patent

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Abstract

The invention relates to a self-adaptive reclosing method for a single-phase earth fault in a bipolar direct-current power grid. The method comprises the following steps: (1) a fault clearing strategy: installing a direct-current circuit breaker (DCCB), i.e., a metal loop circuit breaker (MRCB), on a metal loop, and clearing a fault current through the switching-off of the DCCB and the MRCB afterthe overcurrent locking of a fault MMC; and (2) a self-adaptive reclosing method: based on the characteristics of the potential of a neutral point of a transformer valve side, namely a delta side, distinguishing the nature of the single-phase earth fault in the station so as to realize self-adaptive reclosing.
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Description

technical field

[0001] The invention relates to the field of relay protection and automation of power systems, in particular to a strategy for clearing single-phase grounding faults in a symmetrical bipolar topology MMC-HVDC power grid and an adaptive reclosing method. Background technique

[0002] Due to the advantages of high output current waveform quality, low switching loss, high modularity and easy expansion, the flexible DC transmission technology based on modular multilevel converter (MMC) is widely used in the construction of multi-terminal DC grid and new energy connection. It has good application prospects in fields such as input and consumption, grid asynchronous interconnection and island power supply. The flexible DC system with symmetrical bipolar connection mode has more flexible operation mode and lower overvoltage level, which is in line with the development trend of high voltage, large capacity and multi-terminal DC grid, and has gradually become the mains...

Claims

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