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The Dumarsing Electric active power filters are widely applied in distribution network of industrial, commercial and agencies and organizations, e.g.: power system, electrolytic plating company, water treatment equipment, petrochemical companies, shopping malls and office buildings, sophisticated electronic enterprises, airports / port power supply system, and medical institutions. Depending on the application objects, the DMS-HMP APF application will serve to protect the power supply reliability, reduce interference, and improve product quality, increase service life of equipment and reduce damage to the equipment.

n order to meet the operational needs of the large data center room, the UPS capacity in use in the communication distribution system increases substantially. According to survey, the main harmonic source devices used in the communication LV distribution equipment system are UPS, switching power supply, and inverter air conditioners. The harmonic content it produces are high, and the displacement power factors of these harmonic source devices are extremely high. The active filter can improve the stability of the communication system and the power distribution systems, extend the service life of communications equipment and electrical equipment, and make the distribution system more in line with design specifications on harmonic environment.

The 3rd order harmonics in the semiconductor industry are very serious, mainly in that enterprises use large number of single-phase rectifier equipment. The 3rd harmonics belong to zero sequence harmonics, and are characterized by collecting on the neutral lines, resulting in excessive pressure on the neutral line, or even ignition phenomena, and consequently causing major safety hazard. Harmonics can also cause the circuit breaker to trip, and delay the production time. The 3rd harmonics form circulating currents in the transformer, thereby accelerating the aging of the transformer. Serious harmonic pollution will inevitably affect the efficiency and life of equipment in the distribution system.

Due to production needs, large number of pump loads exist in the petrochemical industry and many pump loads are equipped with frequency converters. The large number of applications of the frequency converters cause significant increase of harmonic content in the distribution system of the petrochemical industry. At present, most frequency converters rectify their currents by 6-pulse AC-to-DC conversion, and the harmonics generated are mainly of 5th, 7th, and 11th order. The main hazards are exhibited as damage to the electrical equipment and deviations in measurement. The use of active filter can perfectly solve this problem.

To substantially increase the melting rate, improve the melting quality of glass, and extend the service life of furnace, and save energy, the electric boosting heating devices are commonly used in the chemical fiber industry, so that the electricity is directly fed via the electrode into the fuel-heated glass tank furnace. These devices can produce a lot of harmonics and the frequency spectrum and amplitude difference of the three-phase harmonic are relatively great.

The medium frequency furnace, rolling mill, and electric arc furnaces commonly used in the steel industry significantly impact the quality of the power grid, e.g. frequent actions of the capacitor compensation cabinet overload protection, severe heating of the transformers and power lines, and frequent blowouts of fuses, and even voltage drop and flicker.

The welder is an essential equipment in the automotive industry. Due to the randomness, rapidness and impact of the welder, the heavy use of welders causes severe power quality problems, resulting in unstable welding quality, function inability of the highly automated robot due to the voltage instability, and inability of normal functioning of the reactive power compensation system.

Large DC motor fields are required to convert AC to DC via rectifier device. As the load capacity of these projects are very considerable, serious harmonic pollution may exist on the AC side, causing voltage distortion and even accidents when circumstances are severe.

Where automated production lines and precision equipment are used, the harmonics will affect its normal use, so that intelligent control system and PLC system fail to function.

The hospitals have very strict requirements on continuity and reliability of power supply. The time for automatic restoration of power supply is T≤15S for Class 0 place, 0.5S≤T≤15S for Class 1 place, and T≤0.5S for Class 2 places, the voltage total harmonic distortion THDu≤3%, and the X-ray machines, CT machines, and MRI are loads with extremely high harmonic content.

The SCR dimming systems, and large LED equipment are harmonic sources, and will produce a lot of 3rd order harmonics during operation, causing low efficiency of power equipment in the distribution system, but also cause lights strobe, noise generation from communication, cable television and other weak electronic circuits, and even malfunction.