Coordinated dynamic reactive power optimization method for phase modifier and hierarchical structure UHV DC receiving end converter station

Abstract

The invention discloses a coordinated dynamic reactive power optimization method for a phase modifier and a hierarchical-structure UHV DC receiving end converter station. The coordinated dynamic reactive power optimization method comprises the main steps of: 1) establishing a hierarchical-structure UHV DC receiving end converter station dynamic reactive power optimization model M; 2) and calculating the hierarchical-structure UHV DC receiving end converter station dynamic reactive power optimization model M, so as to optimize the hierarchical-structure UHV DC receiving end converter station. The coordinated dynamic reactive power optimization method adopts a hybrid solution algorithm based on a nonlinear interior point method and a dynamic programming method, comprises three sub-problems of global optimization based on the nonlinear interior point method, discrete control variable optimization based on the dynamic programming method and continuous control variable optimization based onthe nonlinear interior point method, and has the advantages of high solution efficiency and stable calculation result.

Description

technical field [0001] The invention relates to the field of converter station optimization, in particular to a coordinated dynamic reactive power optimization method for a converter station and a layered structure ultra-high voltage direct current receiving end converter station. Background technique [0002] With the development of my country's UHVDC transmission technology, multi-circuit DC centralized feeding into the load center of the receiving end has become an important issue restricting the development of my country's power grid. severe challenge. For this reason, Chinese experts and scholars took the lead in proposing a new method of UHV DC layered access to the AC grid to solve the problems caused by DC feed-in from the perspective of the grid structure. The topological structure of the DC converter station system in the layered access mode is more complicated. In addition to the AC and DC systems, there are electrical coupling relationships between the high-end a...

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Problems solved by technology

The topological structure of the DC converter station system in the layered access mode is more complicated. In addition to the AC and DC systems, there are electrical coupling relationships between the high-end and low-end converters and the two-layer AC systems of different voltage levels, which greatly increases the reactive power of the system. The complexity of the voltage characteristics, however, for this new access method, the existing research is still in its infancy

On the other hand, the new large-capacity condenser planned and constructed to solve the problems caused by the connection of the UHV DC project to the voltage stability of the AC system lacks an effective coordinated control scheme with the DC system, and its reactive power compensation function is not fully exerted; at the same time , limited by the system filtering, the switching of the AC filter bank must meet its absolute minimum filtering requirements, which may cause excess reactive power to be compensated, especially when the DC transmission power level is low, the converter station may send The AC system injects a large amount of reactive power, aggravating the burden on the AC system

[0003] The dynamic reactive power optimization method is of great significance in realizing the coordination and cooperation between different devices to achieve the goal of minimizing the system network loss or the minimum daily switching times of discrete devices. Report on Research on Dynamic Reactive Power Optimization

Existing researches mainly focus on the reactive power optimization of AC / DC hybrid systems, and take the entire transmission and distribution network as the object, and are not applicable to the local optimization requirements of a single converter station and condenser; at the same time, none of the above studies considered The filtering requirements of the system, the optimization result may not meet the switching requirements of the AC filter

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