Harmonic Calculation Of The Non-ferrous Metal Processing Equipment, Power Supply System And Treatment Methods

With the development of nonferrous metal processing industry, the nonferrous metal processing facilities are developed in the direction of large-scale, wide-range and high-speed. In recent years, our country has built approximately ten 1600mm~2400mm single or double stand double coiler hot rolling mills and six-roller high-speed double coiler cold rolling mills in total in this industry. However, these machines caused serious harmonic pollution problem in power supply system of nonferrous metal processing enterprises. Nonferrous metal processing enterprises have been attached increasing importance to detection and refrainment of harmonic. Combined with an example of 2400mm single stand double coiler hot rolling mill used in nonferrous metal processing enterprises, this paper do some study about calculation and refrainment methods of harmonic.At the aspect of calculation of harmonic, the reason of harmonic comes into being and the problem of harmonic amplification are analyzed, and the calculation method for harmonic voltage and amplify multiple of harmonic electric current is firstly studied in this paper. Then, based on the analysis of some common method for harmonic detection, a new method to measure the harmonic is presented by building a harmonic measure model with nerve network. Combined with an real project example, calculates the harmonic disturb to power network, which is caused by large-capability diode, and the pollution degree to power network in the real is analyzed, which is caused by each times of harmonic.At the aspect of refrainment of harmonic, the construction and theorem of power filter (PF) is introduced, which is used commonly. According to the calculation results of a real project example, presents an effective way to decrease the harmonic pollution, which by using power filter. Meanwhile, the basic model of active power filter and its problem is analyzed, and a basic method is also presented by using active power filter. At last, this paper describes the way that how applies the active power filter to nonferrous metal processing enterprise.