A station domain failure protection system and method for rapid isolation of multiple DC grid faults

Abstract

The invention discloses a station domain failure protection system and method for quickly isolating multi-DC power grid faults, which can shorten the fault isolation time from the traditional 400ms to within 200ms, reduce the transient energy impact during the power grid fault period, and reduce the damage caused by AC fault disturbances. The risk of DC commutation failure greatly improves the level of safe and stable operation of the power grid. The proposed station domain failure protection system can realize the acquisition of voltage, current and circuit breaker position data of the whole station through the hierarchical configuration scheme of the main station and substations. Information exchange can be carried out between different master stations, realizing information exchange such as the location of associated substation circuit breakers, current data, line protection actions, etc., expanding the perception range of the station domain failure protection system. Through the design scheme of the differential loop for station area failure protection, the traditional failure protection criterion is replaced to realize the rapid identification and isolation of failure faults and dead zone faults.

Description

technical field [0001] The invention relates to a station domain failure protection system and scheme for quickly isolating faults of multiple DC power grids, and belongs to the field of relay protection of electric power systems. Background technique [0002] During the transitional period of UHV power grid construction, the characteristics of the power grid "strong direct and weak AC" are prominent, the grid-connected capacity of wind power, photovoltaic and other new energy equipment continues to grow, and major changes have taken place in the grid pattern and power structure. Based on the understanding methods, defense concepts, Control technology has lagged behind the operation practice of UHV AC and DC grids. In recent years, there have been many incidents in China where the commutation failure of the DC system has occurred due to the failure of the AC system. The AC voltage amplitude drop and waveform distortion caused by the AC grid fault cause the voltage drop and ...

AI Technical Summary

Problems solved by technology

[0003] After a short-circuit fault occurs in the AC system, the fault may not be cleared quickly due to the failure of the circuit breaker, and the fault duration will become longer, increasing the risk of DC continuous commutation failure or DC blocking, which will easily cause large-scale power oscillation and large-scale transfer of power flow, which may cause Other cascading failures with serious consequences

The failure of DC commutation in the UHV AC-DC hybrid grid will cause a power fluctuation of about 200ms in the grid, resulting in a large-scale power flow shift in the grid

The traditional failure protection action time is about 400ms. The research on failure protection is limited to the use of AC system criterion optimization, which has certain limitations and cannot completely solve the influence of CT tailing. During the period, the continuous DC commutation fails, which cannot fully meet the stable operation requirements of the UHV AC-DC grid

Images