Long-term voltage stability coordination control method and system for AC/DC system, medium and apparatus

Abstract

The disclosure provides a long-term voltage stability coordination control method and system for an AC / DC system, a medium and an apparatus. After long-term voltage instability occurs in the system, the method executes the following steps cyclically until a control objective is satisfied: switching a layered access DC system operating mode to constant current-constant arc-extinguishing angle control; calculating the initial value information of a UHV DC layered access system based on real-time measured data, predicting the output trajectory of the UHV DC layered access system in combination with time-domain simulation, and calculating the trajectory sensitivity of each bus voltage; solving the optimal control sequence of the system voltage stability coordination control under DC layered access and applying the optimal control sequence to the system. The method coordinates the distribution of DC transmission power in the layered access AC grid, and performs coordination and optimizationcontrol on the DC control amount and the AC control amount of the layered access DC system, so that the power flow distribution of the AC system is reasonable and the long-term voltage stability of the system is improved.

Description

technical field [0001] The disclosure belongs to the field of smart grids, and specifically relates to a method, system, medium and equipment for long-term voltage stability and coordination control of AC and DC systems. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] HVDC transmission has the advantages of long-distance large-capacity transmission and easy connection to asynchronous grids, so it is widely used in trans-regional power transmission to load centers. However, the AC system needs to provide sufficient voltage support for the stable operation of the DC system. As multiple DC lines are fed into the same receiving end system, the problem of voltage stability becomes more prominent. In order to improve the stability of the multi-DC feed-in system from the grid structure, the domestic UHVDC transmission project innovatively propo...

AI Technical Summary

Problems solved by technology

[0005] (1) The research is mainly on the coordinated control strategy between the converters on the inverter side under the layered connection of UHV DC, lacking the coordination between the control of AC and DC systems;

[0006] (2) In the process of long-term voltage instability, there is no basis for the calculation of DC power modulation and the allocation of DC power between the high-end and low-end inverters with hierarchical access

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