A reactive power optimization method for regional power grids including flexible direct current transmission systems

Abstract

The invention discloses a regional power grid reactive power optimization method relating to a flexible HVDC system. The method achieves the purpose of regional reactive power optimization on the flexible HVDC AC and DC parallel system and provides a basis for setting reactive power control reference values for a current converter. The method includes the steps of acquiring basic parameters of a power grid, determining a relational expression of voltage, current and power of the flexible HVDC system, establishing a reactive power optimization objective function with power regulation cost of flexible HVDC considered, determining equality and inequality constraints of corresponding variables according to the variables in the objective function, solving the regional power grid reactive power optimization objective function with the genetic algorithm by considering current constraints of the current converter of the flexible HVDC system under different operation modes, and improving power control strategies according to current converter reactive current optimal solutions obtained by optimal computation. According to the method, the active power regulation cost of flexible HVDC and the current constraints of the current converter are considered, and therefore rationality in setting the reactive power control reference values of the current converter is improved.

Description

technical field [0001] The present invention relates to the technical field of flexible DC power transmission systems with AC and DC lines running in parallel, and more specifically, to a reactive power optimization method for regional power grids with AC and DC lines running in parallel with a flexible DC power transmission system. Background technique [0002] In traditional HVDC transmission, due to the existence of filters, smoothing reactance and other equipment, the converter station needs to consume a large amount of reactive power. However, the reactive power absorbed by the DC converter station from the AC system will aggravate the reactive power shortage of the system, and even cause large fluctuations in the system voltage, which affects the stability of the system voltage. The application of flexible DC transmission technology has greatly improved the performance of HVDC transmission. The VSC-based HVDC converter can achieve decoupling and independent control of...

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Problems solved by technology

[0006] The main purpose of the present invention is to overcome the problem of the Q ref The establishment of the reference value lacks strict theoretical basis, so that the reactive power support capacity of the flexible direct current transmission system to the power grid cannot be effectively utilized, which is not conducive to the further optimization of the reactive power voltage level of the regional power grid.

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