The load analysis includes the load of spinning motors (motors controlled by frequency conversion transmission), various spinning machines, and drawing machines in textile and viscose fiber industries.

Load analysis The cigarette factory has many types of loads, including: production equipment: production equipment on the production line such as silk production line, coiling machine package production line, packing and sealing, etc.

Cement companies are high-power-consuming companies, and their electricity costs account for about one-third of the total cost of cement, and the energy consumption of electric motors accounts for more than 90% of the total load

Load type: mainly air compressor, pump load. The load fluctuation is not big, but the power factor is low, generally only about 0.8, and the harmonic content is small.

Load type: non-ferrous metal refining and chemical industry all use the electrolysis process, so they cannot do without high-power rectifiers. The load fluctuation is small. For the high-power three-phase full-control bridge 6-pulse rectifier device, the harmonic generated by the rectifier device accounts for 25-33% of the fundamental wave, and the characteristic harmonic generated is 6N±1 times. The rectifier itself is a source of harmonics during operation, but at the same time its trigger control system is affected by voltage harmonics. The commutation process of the rectifier will cause a "gap" in the voltage, which affects the detection of voltage zero crossings and the synchronization of control triggers.

Load type: It is mainly a boiler with variable frequency drive, which generates a lot of harmonics during operation.

Load analysis: The petrochemical industry often uses medium and low voltage frequency conversion and speed control drilling rigs, submersible pumps, fans and other refining links such as distillation, cracking, catalysis, hydrogenation, furfural and other production lines (inverters and UPS), polyester chip loads, Coking dump truck and other equipment.

Load types: Various types of AC-DC-AC, AC-AC frequency conversion rolling mills, various types of roll loads, electric arc furnaces, converters, intermediate frequency furnaces, submerged arc furnaces, pressure welding machines, molten steel transport vehicles and other equipment are widely used in the iron and steel metallurgical industry. Active and reactive power fluctuates greatly, which can easily lead to voltage fluctuations and flicker, low power factor, and three-phase imbalance, which will inject a large amount of harmonic current into the grid, causing harmonic pollution.

Welding machines are essential equipment in the automotive and shipbuilding industries. Due to the random, rapid, and impactful characteristics of welding machines, the power quality problems in the automobile manufacturing industry that use welding machines are extremely serious. Practice and analysis show that welding machines bring not only harmonic problems, but It will cause reactive power shocks and cause flicker and voltage drops. In many automobile manufacturers, welding robots with unstable welding quality and higher degree of automation cannot work due to voltage instability, reactive power compensation systems cannot switch normally, and power factors fail to meet the standard and face fines. In automobile painting workshops and production workshops with a relatively high degree of automation, harmonics will also have an impact on automated production lines.

Load analysis: Communication equipment, data room equipment, and special room air-conditioning equipment in telecommunications buildings have very high requirements for power supply continuity and are very sensitive to voltage fluctuations. Various electromagnetic interference will affect data exchange equipment.

Load type: The vast majority of electrical equipment is nonlinear load. Among them, switching power supplies, computers, printers, photocopiers, televisions, elevators, energy-saving lamps, UPS, air conditioners, LED displays, etc., which are widely used, are the main harmonics and reactive power sources in the intelligent building power distribution system. Most of these devices have small capacity, but a large number of them, and the overall impact on power quality is great. There are many single-phase equipment, and its electrical load accounts for about 70% of the total capacity. The use of single-phase power supply causes unbalanced three-phase distribution load, excessive current in the neutral line, and offset of the neutral point. The non-linear load has high harmonic content and low power factor.

Load types: TVs, refrigerators, air conditioners, disinfection cabinets, dishwashers, microwave ovens and other series of household appliances, as well as personal computer electronic products. With the increasing living standards, the electricity consumption of residents has risen sharply. Especially in the summer peak period, the reactive current required for a sharp rise of residential inductive loads increases sharply.