Series null-line current filter and application thereof on power utilization equipment

Abstract

The invention discloses a series null-line current filter. The series null-line current filter comprises a framework and is characterized by also comprising three groups of independent coils, wherein the framework comprises a large iron core at a middle position and small iron cores at two sides, the three groups of independent coils are wound around the large iron core at the middle position, two ends of each group of coil are respectively used as an incoming line end and an outgoing line end of the group of coil and respectively extend out of the framework, the framework is approximately in a square shape, and fixing pieces are arranged around the square framework and are convenient to install. The series null-line current filter is novel in structure, small in size and good in filtering effect, is convenient to install and connect a wire, and is connected in series with a phase line. The invention also discloses application of the series null-line current filter on power utilization equipment, the series null-line current filter is easy to implement, a third harmonic current, a null-line current and a zero-sequence current are effectively prevented from flowing, normal running of the power utilization equipment is not affected, and higher filtering effect is achieved.

Description

technical field [0001] The invention relates to the technical field of filters, in particular to a neutral current filter for phase lines connected in series in a power consumption system, and the application of the filter to power consumption equipment. Background technique [0002] With the continuous development of electric power technology, a large number of non-linear loads, especially more and more electric loads using power electronic technology, have increased sharply, and there is no reasonable distribution of electric equipment, resulting in a large number of zero-line currents , The third harmonic current and the zero-sequence current exist in the neutral line of the system and are fed back to the power supply system. In the three-phase four-wire power system, nonlinear loads such as fluorescent lamps, energy-saving lamps and large display screens in large shopping malls generate a large amount of third harmonic current. If the third harmonic is fed back to the po...

AI Technical Summary

Problems solved by technology

In the three-phase four-wire power system, nonlinear loads such as fluorescent lamps, energy-saving lamps and large display screens in large shopping malls generate a large amount of third harmonic current. If the third harmonic is fed back to the power supply system, the neutral line (zero line) superimposed, so that the transformer of the power supply and distribution line and the zero line in the system are abnormally heated, resulting in the following series of effects: (1), the third harmonic current will increase the loss of the transformer, and long-term operation will cause the zero sequence current of the transformer If it is too large, the temperature rise of local metal parts will increase, which may cause serious consequences of burning the transformer; (2), the cross-sectional area of ​​the neutral wire conductor is generally selected in China to be 50% of the phase wire, and the superposition of the third harmonic current will cause the neutral wire (3) The third harmonic will damage the lighting source due to flickering, and the image display equipment will flicker and display distortion, which will affect the normal work; (40 1. The existing neutral line current eliminators are connected in parallel, occupy a large area, and the filtering effect is lower than 70%, which is far from meeting the requirements of the power supply system; (5) The parallel neutral line current absorbers have a large volume, Poor heat dissipation, high loss, and limited installation methods

[0003] As mentioned above, the third harmonic and zero-sequence current in the system have affected the operation of equipment, and there are potential safety hazards. It is necessary to effectively control the third harmonic current and zero-sequence current in the power system

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