Harmonic isolation method and device for power supply system

Abstract

The invention relates to a method and a device for isolating harmonic waves of power supply and consumption systems. The method and the device are based on a technology for managing the harmonic waves. The method includes setting variable reactor and capacitor serial-parallel connection assemblies and connecting the variable reactor and capacitor serial-parallel connection assemblies into an inlet of a harmonic wave source; detecting harmonic wave contents and power supply and consumption conditions of two access ends of each assembly in real time; dynamically controlling parameters of serial-parallel connection variable reactors and capacitors according to the detected harmonic wave contents, effectively isolating the harmonic waves and allowing the harmonic waves to flow on the sides of the harmonic wave source; dynamically adjusting the parameters of the serial-parallel connection variable reactors and capacitors according to the power supply and consumption conditions, enabling filter indexes of the power supply and consumption systems to reach standards and increasing power factors of the power supply and consumption systems. The device comprises a variable reactor and capacitor serial-parallel connection unit, a harmonic wave isolation detection unit, a harmonic wave isolation control unit, a harmonic wave isolation execution unit and a harmonic wave isolation protection unit. The method and the device are used for isolating the power harmonic waves, purifying a power grid, improving the quality of electric energy, reducing loss, saving energy, improving the power supply and consumption reliability and the electric energy utilization efficiency, and have the advantages of safety, environmental protection, energy conservation and capability of improving the efficiency.

Description

technical field [0001] The invention relates to a harmonic control technology, in particular to a harmonic isolation method and device for a power supply and consumption system. Background technique [0002] In modern industrial and civil power supply systems, due to the existence of a large number of non-linear loads, such as: electric arc furnaces, induction furnaces, electric locomotives, rectification equipment, frequency conversion equipment, fluorescent lamps, gas discharge lamps and other high-power semiconductor devices or arc, ferromagnetic Non-linear loads such as equipment will generate a corresponding nonlinear current in the grid; while the nonlinear current will cause a voltage drop on the grid impedance, distorting the supply voltage waveform and turning it into a non-sinusoidal wave; the non-sinusoidal wave can be decomposed into 50Hz The power frequency fundamental and many harmonics (2nd, 3rd, 4th, 5th, ...) that are integer multiples of the fundamental. A...

AI Technical Summary

Problems solved by technology

[0003] ① Harmonic current causes the system power utilization rate to decrease and power loss to increase;

[0004] ② It has a current amplification effect on the capacitor and affects reactive power compensation;

[0005] ③Reduce the power factor of the system, and the compensation device cannot improve the power factor;

[0006] ④The phenomenon of cable heating, partial discharge, breakdown, blasting and fire is more, and the service life of the cable is shorter;

[0007] ⑤ Due to the increase of system loss, transformers, lines, electric equipment, etc. will heat up, insulation will age, and the service life will be shortened;

[0008] ⑥ System harmonic resonance and loud noise may cause transformer resonance or burnout, voltage transformer overvoltage explosion or fuse blown;

[0009] ⑦Harmonic pollution causes relay protection and automatic device malfunction, resulting in multiple power outages for unknown reasons in the system;

[0010] ⑧ The anti-interference ability of microcomputer system, data transmission system, automatic wave recording system and relay protection device is reduced, and there are phenomena such as data loss, misoperation, misdisplay, communication interruption, etc.

However, for the filtering of nonlinear loads (harmonic sources) with rich harmonic content, the filtering effect of passive filtering devices and active filtering devices is poor

Moreover, passive filtering devices need to design more filters, and their cost and loss increase; active filtering devices require higher detection, response speed and output power, and their costs and power consumption are further increased.

In addition, the harmonic control principle of existing passive filter devices and active filter devices is a centralized processing mechanism connected in parallel. Local harmonic sources will amplify and pollute the entire power grid through cables and capacitors. Users of Harmonic Sources

Moreover, in many occasions, although filtering measures have been adopted, the harmonic content of the monitoring point still exceeds the standard

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