Frequency stabilization control method for alternating-current/direct-current series-parallel system

Abstract

The invention discloses a frequency stabilization control method for an alternating-current/direct-current series-parallel system, which comprises the steps of designing an under-frequency load shedding optimization model considering emergency power generation control and high-voltage direct current power support, providing an objective function giving consideration to the frequency recovery performance and the load shedding amount, selecting the action frequency of an under-frequency load shedding program and the load shedding amount of each turn as control variables, carrying out optimization on a scheme by using a cloud adaptive particle swarm algorithm containing a dimension mutation operator, and realizing intelligent control for the frequency of the alternating-current/direct-current series-parallel system. The control method disclosed by the invention solves a problem of coordination and optimization between the system instability possibly caused by frequency oscillation after the alternating-current/direct-current series-parallel system breaks down and the economy of system frequency recovery; an under-frequency load shedding scheme is optimized, an optimal setting scheme is searched intelligently, the frequency recovery performance is considered, the load shedding amount is minimized, and the transient-state performance and the steady-state performance of the alternating-current/direct-current series-parallel system are improved.

Description

technical field [0001] The invention relates to the field of protection and control of modern power systems, in particular to a frequency stabilization control method for an AC / DC hybrid system. Background technique [0002] Frequency is one of the important indicators to measure the quality of electric energy. Abnormal frequency will bring many adverse effects to the power system. In severe cases, it will endanger the stability of the system and affect the economy of system operation. [0003] Under-frequency load shedding (UFLS) is one of the most important means to restore frequency stability when there is a large active power deficit in the power system. At present, the LF load shedding methods mainly include traditional LF load shedding and adaptive LF load shedding. Traditional low-frequency load shedding schemes at home and abroad are mainly set by operators based on actual system operation experience and computer simulation analysis conclusions. The traditional UFL...

AI Technical Summary

Problems solved by technology

The traditional UFLS scheme adopts fixed delay and fixed cutting amount, which is set offline, and the real-time performance is poor, which may cause over-cut or under-cut

Adaptive low-frequency load shedding based on the frequency change rate, although the action time and load shedding amount can be set flexibly, most of them do not consider the system topology, the frequency characteristics of the generator and the frequency characteristics of the load, which may lead to unnecessary load loss

In addition, when frequency oscillation occurs, only using the instantaneous rate of change of frequency as a signal may cause inaccurate measurements

[0004] With the development of UHV power grid and EHVDC transmission, more and more complex grid structures and changing operation modes will make frequency control more complicated

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