Method for suppressing voltage vluctuation and harmonic distortion through static synchronous compensator in distribution network

Abstract

The invention relates to a method for suppressing voltage fluctuation and harmonic distortion through a static synchronous compensator in a distribution network. The method comprises: detecting electric parameters at a PCC of the distribution network; calculating a positive-sequence reactive output, a negative-sequence reactive output, and a t-order harmonic active output of a DSTATCOMi connected to the same PCC; calculating a positive-sequence voltage, a negative-sequence voltage , and a t-order harmonic voltage compensation reference value of the PCC; calculating a virtual positive-sequence susceptance, a negative-sequence susceptance, and a harmonic conductance of the DSTATCOMi based on universal impedance shape; calculating a positive-sequence, negative-sequence, and harmonic output current reference value of the DSTATCOMi; synthesizing the output current reference value of the DSTATCOMi to perform proportional current limitation according to priorities; and synthesizing PWM signals from the DSTATCOMi control system to perform pulse width modulation. The invention can achieve a reasonable cooperation between overall control over PCC electric energy quality and protection of the distribution network, enhance both local and regional voltage quality in the distribution network, and ensure the security and the stable operation of the distribution network.

Description

Technical field: [0001] The invention belongs to the field of electrical engineering, distributed power generation, active distribution network and power quality management, and relates to a method of using unified impedance construction technology to realize the parallel operation of multi-distribution network static synchronous compensators without interconnection lines to suppress the common bus voltage of distribution network Control methods for wave and harmonic distortion. Background technique: [0002] The traditional distribution network usually relies on a flexible network structure and a large capacity margin to cope with the uncertainty of the load, so as to ensure the safety and reliability of the power system, and its operation control method is relatively simple. In the past ten years, the rapid development of power electronics technology has solved the problem of grid-connected operation of distributed generation (DG) in the medium and low voltage distribution...

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Problems solved by technology

Although the design idea of ​​DSTATCOM using this kind of control method is simple and clear, it lacks the control of PCC unbalanced voltage and cannot effectively suppress PCC voltage distortion. Especially when it is installed near DG, its compensation effect will be greatly affected, and it is difficult to Realize the safe and reliable parallel operation of multiple DSTATCOMs, all of which are inconsistent with the requirements of the active distribution network

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