Intelligent comprehensive optimization device for power quality

Abstract

The invention provides an intelligent comprehensive optimization device for power quality. In the device, a DVR converter, a first direct current capacitor and an APF converter are connected in parallel to form a first compensation loop for voltage compensation; the DVR converter, a second direct current capacitor and a second APF converter are connected in parallel to form a second compensation loop for harmonic treatment and reactive compensation; load compensators are used for recording parameters of starting, running, cutting and the like of specific loads; a direct current voltage fluctuation suppressor is used for suppressing direct voltage of the first direct current capacitor and direct voltages of the second direct current capacitor; a network controller is used for achieving control over voltage compensation of the first compensation loop and control over harmonic treatment and reactive compensation of the second compensation loop and providing a corresponding compensation algorithm according to parameter variation rules in the load compensators. According to the intelligent comprehensive optimization device for the power quality, the compensation voltage drops when network voltage drops, harmonic treatment and reactive compensation are conducted when no drop exists, voltage fluctuation can be suppressed for obtaining high-quality output waveform, and the compensation speed of a user for conducting power quality compensation can be increased.

Description

Technical field [0001] The invention relates to the technical field of power systems, in particular to an intelligent comprehensive optimization device for power quality. Background technique [0002] UPQC (Unified Power Quality Conditioner) is usually composed of a series voltage source converter and a parallel voltage source converter through a common DC bus. It is installed near the harmonic load on the user side. At the same time, the voltage and current are compensated. The series voltage source converter functions as a DVR (Dynamic Voltage Restorer, dynamic voltage compensator), which can suppress voltage fluctuations, compensate for power supply voltage harmonics, and eliminate voltage swells or voltage sags that often occur in power distribution systems. Improve the damping of the device. The parallel voltage source converter functions as an APF (Active Power Filter), which can filter out load harmonic currents and compensate load reactive power. [0003] Such as figure ...

AI Technical Summary

Problems solved by technology

[0004] During the working process of UPQC, it is necessary to coordinate the DVR function and the APF function. When there is a voltage drop, the DVR function starts. At this time, there are two options for the APF function: 1. Synchronously stabilize the voltage of the DC capacitor C1*, which is used for voltage drop compensation, but there are disadvantages The reason is: UPQC no longer has harmonic and reactive power compensation. When the series side is performing voltage compensation, the harmonics and reactive power of the grid will have peak values, and harmonic processing and reactive power compensation must be performed in time; 2. Compensate harmonics, The DC capacitor C1* voltage is no longer maintained, but the disadvantage is that the DVR compensation function is limited, because the DVR function is completed only by the energy stored in the DC capacitor C1* and its auxiliary energy storage device. When the energy is used up, the DVR compensation function ends until the DC voltage Allow C1* to return to normal state before the next DVR compensation action can be performed

[0005] Through retrieval, the Chinese Patent Publication No. CN 104393599 A discloses a unified power quality adjustment device and method, which solves the above problems well. However, in this solution, the inventor found that in the above two APF function selections , the voltage of DC capacitor C1* is easy to fluctuate, which is not conducive to obtaining high-quality output waveforms, and because the harmonic and reactive power characteristics of user loads are regular, users cannot obtain excellent compensation speed for power quality compensation

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