Zhengjiang Naisi Co., Ltd

Active Harmonic Filter

The Industry

There are a number of electrical devices that have nonlinear operating characteristics i.e even when applied voltage is sinusoidal in nature, the current drawn by the device is non-sinusoidal in nature. These nonlinear devices used in power distribution circuits create nonlinear currents and which subsequently causes voltage distortions. These nonlinear currents and voltages have been generally referred to as harmonic currents and voltages. The proliferation of electronic switching devices in modern equipment has resulted in a significant increase in the amount of harmonic pollution in the electrical distribution systems. These harmonics if disregarded or undetected may cause harmonic resonant conditions, which could present system operating problems resulting in complaints from customers and reduced life of power equipment as well as degraded efficiency and performance. Harmonic currents and voltages can cause many unfavourable effects on the power system itself and the connected loads. Malfunctioning of electronic equipment, capacitor failure, transformer and neutral conductor over overheating, excessive heating in rotating machinery are some of these effects.

Background

Zhenjiang Naisi New Material Co., Ltd. is mainly engaged in the production and sales of new ultra-hard composite wear-resistant cutting wires, photovoltaic wire cutting wheel recycling coating process processing, production of steel cords, technical services and testing services for the above products, self-operated and acting for the import and export business of various commodities and technologies (except for commodities and technologies that are restricted by the state or prohibited from import and export), sales of silicon materials.

Power Quality Problem

Due to the Harmonic Voltage and Harmonics Current in the old factory building of the customer, the capacitors are often damaged, so the need for harmonic mitigation is generated.

Solution

In view of the high current distortion rate (High THDi)and voltage distortion rate(THDv) in the field, installing an Active Harmonic Filter at the low-voltage side can reduce Current Harmonics (THDi) and Voltage Harmonics accordingly.

Performance

There are some harmonic problems in ZhengJiang Naisi New Material Co., Ltd. In order to avoid the impact of harmonics on the normal work of the factory, An Active Harmonic Filter is installed to control the harmonics. After AHF installation, the field harmonic problem has been well improved, and the current distortion rate is reduced from about 30% to about 1.5%.

The harmonics include the 3rd, 5th, and 7th harmonics, and the 5th harmonic is the most serious. After the Active Harmonic Filter is installed, the waveforms are close to standard sine waves, and after compensation, the harmonic current content is significantly reduced, achieving a perfect compensation effect.