Adaptive emergency control method for frequency stability of large-capacity multi-DC feed-in grid

Abstract

The invention discloses a frequency stability adaptive emergency control method for a high-capacity multi-infeed DC power grid. The influences of the heat storage capacity of a boiler, main steam pressure of a steam turbine, an operation mode of a CCS and parameter setting of a speed regulating system on the frequency modulation ability of a thermal power unit are simulated through a pressure feedback link, a flow change link and a valve opening limiting link in an electromechanical transient simulation process; different power vacancies are simulated through DC blocking and DC power emergencyreduction and the power vacancy corresponding to frequency stability critical safety is calculated; the total power control amount of emergency control measures during action within given time is calculated according to an SFR model; and the electric quantity of primary frequency modulation of the system is calculated according to the operating conditions of the thermal power unit at the calculation moment and the current moment separately and the effective state of an online strategy in a safety control system is updated in real time.

Description

Technical field[0001]The present invention relates to a large-capacity multi-DC feed-in-input grid frequency stable adaptive emergency control method, which belongs to the technical field of power system automation.Background technique[0002]EHFD DC transmission is a major technical means for supporting energy optimization configurations and energy saving and emission reduction. Contains multiple returns of large capacity DC transmission lines have become the main feature of the receiving grid. The size of the high-voltage DC transport capacity and renewable new energy access capacity is increasing. It is gradually replacing the conventional energy unit. The overall inertial time constant of the system is reduced, and the average utilization hours of the coal-fired thermofer unit have declined. The high-voltage DC lock failure will result in a large power absence and a large impact on the system frequency. The reduction in the operating spare of the fire generator will result in an i...

AI Technical Summary

Problems solved by technology

[0004] After determining the parameters of each link of the thermal power unit frequency regulation system, the system frequency response model (SFR) can be used to calculate the minimum frequency and load shedding of the system through an analytical method, but this method aggregates all units into one unit, and the calculation accuracy poor

Full-state numerical simulation can obtain detailed system frequency dynamics, and can consider the time-space distribution characteristics of the frequency dynamic process, but the calculation amount is often large

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