A tire manufacture company in Shandong Province was transformed and established in 1996, occupying a site area of 350,000 m2 and having more than 1,100 employees, including around 200 engineering technical personnel. Its predominant products comprised of over 200 specifications and types such as semi-steel radial tires, load-bearing vehicle tires, light truck tires, agricultural tires, medium and small engineering tires, giant engineering machinery tires, etc. Its annual yield of tires of various types was 10 million sets.

The enterprise employed 690 V F270 and F370 enclosed roll mills, which generated a great amount of harmonics during operation and were of great power consumption and low power factor. The distortion rates of harmonic voltage were as high as 8% to 13%, which had significantly contaminated the grid, and resulted in great damage to the electric equipment as well as the machine itself. Greater harmonics and currents would give rise to greater heating of silicon controlled rectifiers, severely jeopardizing the service lives of the latter and causing great potential hazards to the equipment and the grid. On this account, the company introduced the harmonic suppressor and VAR compensator (passive filtering) manufactured by CEAYEA Electrical & Technology (Shanghai) Co., Ltd. The suppressor and compensator employed LC filtering circuits and comprised mainly of filter capacitors, filter reactors, contactless switches, controllers and protective systems. It was running in parallel to the harmonic sources, and was designed in accordance with the characteristics and content of harmonic currents and the reactive power of the system. The filtering branch provided the harmonic currents with a passage of extremely low impedance, so that most of the harmonic currents would be absorbed by the filter, significantly reducing the injection of harmonic currents and voltage distortion rate of the system. In the meanwhile, the device, since installation and commissioning, had perfectly solved the potential hazards to electricity use for the customer and improved the power quality of the grid. The harmonics were also limited to the national standards, improving both the power factor and the production efficiency of the equipment.