Consumers successively plunged a large number of silicon controlled commuted devices ( such as steel rolling 、 electrized locomotive 、 aluminium electrolysed devices etc ) and smelting devices to improve their produced efficiency or to save energy . on the one hand it is good for consumers , on the other hand it will arouse the fluctuation of voltage and frequency and it will result in the collision of the active and reactance capacity . meanwhile these nonlinear loads bring much harmonic into the electric network which deteriorate the quality of power supply and hazard the online device enormously 用電部門為了提高生產(chǎn)效益、節(jié)約能源,在大電網(wǎng)中相繼出現(xiàn)了大量的可控硅整流裝置(如軋鋼、電氣化機(jī)車、鋁加工電解設(shè)備等)以及冶煉設(shè)備,這些設(shè)備的投入使用對(duì)節(jié)能有一定好處,但給電網(wǎng)造成有、無功沖擊,引起電壓和頻率的波動(dòng),同時(shí),這些非線性負(fù)荷向電網(wǎng)注入大量諧波,大大惡化了供電系統(tǒng)的電能質(zhì)量,給用電設(shè)備帶來了極大的危害。