Precision discrete optical power flow calculation method of VSC-HVDC (voltage source converter based high voltage direct current) containing AC/DC system

Abstract

The invention relates to a precision discrete optical power flow calculation method of a VSC-HVDC (voltage source converter based high voltage direct current) containing AC / DC system. The calculation method is characterized by comprising the steps of firstly analyzing a power steady-state equation and other modified equations of the VSC-HVDC containing AC / DC system, then setting equality constraints and inequality constraints, and finally introducing a positive curvature quadratic penalty function into an interior point method. According to the calculation method, the interior point method is adopted to carry out optimization on continuous variables of the AC / DC system, the penalty function is introduced when a certain condition is reached, and discrete variables are constrained and optimized. Meanwhile, parameter values of the penalty function are continuously adjusted according to variations of the iteration quantity, and finally a purpose of optimizing the continuous variables and the discrete variables simultaneously is achieved.

Description

technical field [0001] The invention relates to a precise discrete optimal power flow calculation method for a VSC-HVDC AC and DC system, and belongs to the technical field of power system operation and control. Background technique [0002] The voltage source converter based high voltage direct current (VSC-HVDC) technology based on voltage source converter (VSC) and fully controlled switching devices is a new generation of DC transmission technology, which solves the problem of traditional HVDC transmission. It has many technical difficulties, but also has many advantages, such as fast and independent control of active and reactive power; fast reactive power support for the AC side; faster power flow reversal, and easier realization of parallel multi-stage DC systems. Based on the above reasons, VSC-HVDC and AC / DC systems will not only be more and more applied in practical engineering, but also become the research hotspots of many scholars. [0003] The component characte...

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Problems solved by technology

[0003] The component characteristics and mathematical model of VSC-HVDC are quite different from the traditional HVDC transmission model. The original algorithm for AC-DC optimal power flow applicable to traditional HVDC transmission cannot be applied to the optimal power flow of VSC-HVDC system. Optimal Power Calculation

In the article "Reactive Power Optimization of AC and DC Systems Based on Singular Value Decomposition and Interior Point Method", the OPF model of AC and DC systems is used for the calculation of reactive power optimization configuration schemes, but the VSC-HVDC system is not considered; the article "Modeling of VSC-based HVDC systems for a Newton-Raphson OPF algorithm" Based on the Newton-Raphson method, a solution to the OPF problem involving VSC-HVDC AC and DC systems is proposed, but because this method generally uses iterative experimentation, it is difficult to realize it through programming

[0004] Primitive-dual interior point method (abbreviated as interior point method) has great advantages in dealing with continuous variable optimization problems, with strong robustness and good convergence, but it is difficult to deal with discrete variable optimization problems; intelligent algorithms have Good discrete variable processing ability, the literature "reactive power optimization hybrid strategy based on genetic algorithm and interior point method" "reactive power optimization combination strategy based on interior point method and improved genetic algorithm" proposed intelligent algorithms such as interior point method and genetic algorithm Combined hybrid algorithm to deal with the optimization problem of discrete and continuous variables, but the optimization speed of this kind of algorithm is too slow and the calculation time is long. At the same time, when calculating the OPF problem of AC-DC system with VSC-HVDC, it is necessary to specify the DC control mode , which will cause the intelligent algorithm to fall into a local optimal solution or cause the algorithm to oscillate

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