Ordinary capacitors have amplification of harmonics, harmonic control design, a series of reactors must either protect the capacitor, and can effectively prevent system harmonics is amplified. According to GB50053-94 "10kV and below substation design specifications," provides that "when a nearby high harmonic content capacitor means exceeds the allowable value, harmonic control sales, should be set in a series of harmonic suppression loop reactor . "GB50227-95" shunt capacitors design specifications, "provides that" for suppressing harmonics, when the background of shunt capacitors connected to the grid at the harmonics of 5 times or more, should take 6%; when shunt capacitors connected Background harmonics into the grid at three times or more, and harmonic control, should take 12 percent. " In summary, in the construction of communications power systems, harmonic control measures should be based on a detuned circuit, first consider the use of the active filter control. Preferably in the initial stage of construction will be considered resolved. As in the construction of UPS systems, active filters configured directly, it will not only ensure the construction of the system more secure and reliable, and because you can easily achieve the end of treatment, so that the power supply reliability and power efficiency has increased. With the development of science and technology, with the level of industrial production and people's living standards, a large number of non-linear electrical equipment put into operation in the grid, resulting in a harmonic component grid accounted for an increasing proportion. It not only increases the power loss of the power grid, and the grid protection device interference with the normal operation of automation devices, causing these devices malfunction and refused to move, a direct threat to the safe operation of the grid. Power system harmonics from the electrical equipment, that is to say from the power generating equipment and electrical equipment. Since the magnetic field generated by the rotor of the generator can not be perfect sine wave, the voltage waveform generator issue can not be a little distorted sine wave Harmonic learning Connaught Electrical and Mechanical factory _ _ Harmonic learning from Henan Connaught Electrical and Mechanical Equipment Limited. Henan Xi Connaught Electrical Equipment Co. (www.hnxinuo.com) located in the south China city of Zhengzhou Area 6B 6B-3-342. Scraps and development in the wave of market economy, the current study Connaught Electrical and Mechanical has a high profile in the electronics, electrical products processing, enjoys a good reputation. Xi Connaught Electrical and Mechanical made whole network business alliance certification, marking our service and management level has reached a new height. Xi Connaught Electrical and Mechanical staff is willing to joint development with all people a better future.