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Active filter capable of simultaneously compensating reactive power and controlling harmonic waves and control and design method

A technology of passive filter and source filter, applied in active power filter, AC network to reduce harmonic/ripple, reactive power compensation, etc. and other issues to achieve the effect of engineering practicability

Active Publication Date: 2020-12-08
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This is because the harmonics generated by the converter are mostly high-order characteristic harmonics such as the 12th and 24th, which are easy to pass through capacitive devices such as capacitors, while reactive power compensation equipment is essentially to compensate the fundamental frequency current, which is easy to Flowing through inductive devices such as inductors, active filter devices often cannot take into account both fundamental frequency reactive power compensation and high frequency filtering at the same time, so they cannot replace passive filters that are both reactive power compensation devices and filter devices on the AC side

Method used

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  • Active filter capable of simultaneously compensating reactive power and controlling harmonic waves and control and design method
  • Active filter capable of simultaneously compensating reactive power and controlling harmonic waves and control and design method
  • Active filter capable of simultaneously compensating reactive power and controlling harmonic waves and control and design method

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Embodiment 1

[0032] Such as figure 1 As shown, the present invention provides an active filter that simultaneously compensates reactive power and controls harmonics. Its primary system includes a switchable device, a converter valve and a connecting device, and the converter valve is connected to the AC bus through the connecting device , the AC bus is connected to the AC system and the harmonic source respectively. Among them, the converter valve of the turn-off device is composed of three-phase commutation bridge arms, and each phase commutation bridge arm is composed of a DC support capacitor and a turn-off device. The output voltage of the converter valve of the device. Because zero-sequence harmonics need to be filtered out, generally the 3-phase commutation bridge arms are connected in a Y-connected neutral-point grounding manner. The connected equipment includes transformers and passive filters connected in parallel. As an inductive device, the transformer has a very low impedance...

Embodiment 2

[0034] Such as figure 2 As shown, the present invention also provides a control method of an active filter that simultaneously compensates reactive power and controls harmonics, including the following:

[0035] (1) Measure the harmonic current of the harmonic source and the harmonic current of the low-voltage side connected to the passive filter in the active filter, and calculate the current of the converter valve in the active filter based on the measured current data Harmonic modulation voltage for harmonic control.

[0036] The active filter takes the harmonic current as the control quantity, and controls the harmonic current flowing into the AC bus on the high-voltage side of the active filter and the harmonic current flowing out of the harmonic source to have the same amplitude, opposite phase, and cancel each other. In the topological structure of the active filter designed in the present invention, the connection transformer as the connection equipment and the conne...

Embodiment 3

[0052] Such as Figure 3 ~ Figure 5 As shown, the present invention also provides a method for designing an active filter that simultaneously compensates reactive power and controls harmonics, comprising the following steps:

[0053] (1) Perform equivalent analysis on the active filter to obtain the equivalent circuit diagram of the active filter, and perform harmonic analysis and fundamental frequency analysis on the active filter based on the equivalent circuit diagram.

[0054] a. Equivalent circuit analysis

[0055] The connecting device of the active filter designed in the present invention is formed by connecting a transformer and connecting a passive filter in parallel. Since the connecting transformer belongs to a magnetic coupling device, the primary side and the secondary side are not directly connected through a circuit, so it has complex analysis, unintuitive question. The circuit equivalent of the connected transformer is helpful for the design of each device. ...

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Abstract

The invention relates to an active filter capable of simultaneously compensating reactive power and controlling harmonic waves and a control and design method, and a primary system of the active filter comprises a turn-off device converter valve which is connected with an alternating current bus through connecting equipment; the turn-off device converter valve comprises three phases of converter bridge arms, each phase of converter bridge arm is composed of a direct-current supporting capacitor and a turn-off device, and the output voltage of the turn-off device converter valve is controlled by controlling the turn-on and turn-off of the turn-off device; the connecting equipment comprises a connecting transformer and a connecting passive filter which are connected in parallel, and the connecting transformer is used for allowing fundamental frequency reactive current to flow through in a low-frequency band; and the connection passive filter is used for allowing high-frequency harmonic current to flow through the high-frequency band. The method can be widely applied to the field of power transmission system design.

Description

technical field [0001] The invention relates to an active filter capable of simultaneously compensating reactive power and controlling harmonics, and a control and design method, belonging to the field of power transmission system design. Background technique [0002] LCC DC conversion project will consume a lot of reactive power and generate a lot of harmonics during operation, mainly the 12th, 24th and other characteristic harmonics and the 3rd and 5th non-characteristic harmonics, so a large number of AC filters must be installed Therefore, the AC filter field composed of AC filters and shunt capacitors accounts for nearly half of the area of ​​the LCC DC converter station and costs a lot of investment. [0003] The AC filter is a passive filtering device, and its filtering effect is affected by the impedance of the AC system. It needs to be designed in detail according to the AC system conditions during the design process of the converter station. At present, the constr...

Claims

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Application Information

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IPC IPC(8): H02J3/18H02J3/01
CPCH02J3/1857H02J3/01Y02E40/40
Inventor 郭铭群王绍武季一鸣王玲吴方劼杨一鸣郝致远杜商安
Owner STATE GRID CORP OF CHINA
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