Co-optimized configuration method of current limiting reactor and fault current limiter in flexible and direct grid

Abstract

The invention relates to the technical field of flexible direct current power grids, in particular to a collaborative optimization configuration method for a current-limiting reactor and a fault current limiter in a flexible direct current power grid. Comprehensively considering the system performance and the cost of current limiting equipment, the current limiting effect, the total inductance value of the current limiting reactor, and the number of fault current limiters are used as the objective function, and the breaking current of the DC circuit breaker, the overcurrent protection of the converter valve, and the current limiting With the reactor as the constraint condition, a multi-objective optimal configuration mathematical model is established, and the multi-objective mixed leapfrog algorithm is used to solve the problem, and the optimal solution set is obtained. Combined with the actual situation, an appropriate configuration scheme is selected in the optimal solution set. According to this method, the current-limiting reactor and fault current limiter in the flexible direct grid are optimally configured to achieve the best current-limiting effect, the smallest total inductance of the current-limiting reactor, and the least number of installed fault current limiters. The optimization target can ensure the continuous and stable operation of the healthy part of the flexible DC grid when a fault occurs.

Description

technical field [0001] The invention relates to the technical field of flexible direct current power grids, in particular to a collaborative optimization configuration method for a current-limiting reactor and a fault current limiter in a flexible direct current power grid. Background technique [0002] The flexible DC power grid is an important direction for the development of modern power grids. The modular multilevel converter MMC has been widely used in flexible DC projects due to its advantages of less harmonic content, low switching frequency, and high reliability. Due to the low damping characteristics of the flexible DC grid, the DC fault develops rapidly and affects a wide range, which seriously threatens the safe and reliable operation of the system. Ensuring the survivability of the flexible DC grid under fault conditions is a key technical difficulty at present. [0003] The solution of configuring DC circuit breakers at both ends of the line is used to quickly ...

AI Technical Summary

Problems solved by technology

However, this solution currently faces two problems: 1) With the development of DC systems towards high-voltage and large-capacity, the development of corresponding high-voltage and large-capacity DC circuit breakers is restricted by the current technical background and investment costs

2) The insulated gate bipolar transistor (IGBT) in the converter valve has weak current resistance capability. Once the fault current of the MMC bridge arm exceeds the over-current protection threshold of the converter valve, the MMC will be blocked to protect the IGBT, causing a fault The scope of the spread is expanded, which is contrary to the original intention of using DC circuit breakers to quickly isolate faults in the flexible DC power grid

At present, the collaborative configuration of CLR and FCL in the flexible DC grid still lacks an effective and reliable theoretical method. Although a configuration scheme that meets the conditions can be found by using simulation, it cannot achieve the global optimal configuration.

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