Coordinated control method, system, medium and equipment for long-term voltage stability of AC and DC systems

Abstract

The present disclosure provides a long-term voltage stability coordination control method, system, medium and equipment of an AC-DC system. After long-term voltage instability occurs in the system, the following steps are cyclically executed until the control target is met: the DC system with layered access is operated The mode is switched to constant current-constant extinguishing angle control; the initial value information of the UHV DC layered access system is calculated based on real-time measurement data, and the output trajectory of the UHV DC layered access system is predicted in combination with time domain simulation. The trajectory sensitivity of each bus voltage is calculated; the optimal control sequence of the coordinated control of system voltage stability under DC layered access is solved and applied to the system. This disclosure coordinates the distribution of DC transmission power in the layered access to the AC grid, and at the same time coordinates and optimizes the control of the DC control amount and the AC control amount of the layered access to the DC system, making the power flow distribution of the AC system more reasonable and improving Long-term voltage stability of the system.

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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