A unified power quality adjustment device and method

Abstract

The invention discloses a uniform power quality regulating device and method. The uniform power quality regulating device comprises a DVR converter, a first and a second APF converter, a first and a second direct-current energy storage capacitor, a transformer, a first and a second electric reactor and a network controller; the DVR converter, first direct-current energy storage capacitor and APF converter are connected in parallel to form a first compensation loop for voltage compensation; the DVR converter, second direct-current energy storage capacitor and second APF converter are connected in series to form a second compensation loop for harmonic treatment and reactive compensation; the network controller is used for controlling the voltage compensation of the first compensation loop and the harmonic treatment and reactive compensation of the second compensation loop. The uniform power quality regulating device and method are capable of stabilizing the direct current capacitance to compensate the voltage drop when a power grid appears voltage drop, and meanwhile, the uniform power quality regulating device and method duly perform the harmonic treatment and reactive compensation.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a unified power quality adjustment device and method. Background technique [0002] UPQC (Unified Power Quality Conditioner, 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, which can Simultaneously compensate for voltage and current. The series voltage source converter acts as a DVR (Dynamic Voltage Restorer, dynamic voltage compensator), which can suppress voltage fluctuations, compensate power supply voltage harmonics, and eliminate voltage swells or voltage sags that often occur in power distribution systems , increasing the damping of the device. The parallel voltage source converter plays the role of APF (Active Power Filter, active power filter), which can filter out the load harmonic current and compen...

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Problems solved by technology

[0005] Both options of the above APF function have shortcomings. The disadvantages are: for the first option, UPQC no longer has harmonic and reactive power compensation. When the series side is performing voltage compensation, the harmonics of the power grid There will be peaks in the reactive power and reactive power, and harmonic processing and reactive power compensation must be performed in time; for the second option, the DVR compensation function is limited, because the DVR function is only completed by the energy stored in the DC capacitor C1* and its auxiliary energy storage device , the DVR compensation function will end when the energy is used up, and the next DVR compensation action will not be performed until the DC capacitor C1* returns to a normal state

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