在供電(dian)(dian)(dian)系(xi)統(tong)中(zhong)(zhong)，理(li)想的(de)交流(liu)電(dian)(dian)(dian)壓(ya)／電(dian)(dian)(dian)流(liu)星(xing)正(zheng)弦波(bo)(bo)形(xing)，但當正(zheng)弦電(dian)(dian)(dian)壓(ya)（或(huo)非正(zheng)弦電(dian)(dian)(dian)壓(ya)）施加在非線性(xing)負載(zai)(zai)上，電(dian)(dian)(dian)流(liu)就(jiu)會(hui)畸變成非正(zheng)弦波(bo)(bo)，非正(zheng)弦波(bo)(bo)的(de)電(dian)(dian)(dian)流(liu)流(liu)經(jing)帶有(you)咀抗的(de)電(dian)(dian)(dian)網就(jiu)會(hui)產(chan)(chan)生壓(ya)降，進而(er)使得電(dian)(dian)(dian)壓(ya)波(bo)(bo)形(xing)產(chan)(chan)生畸變。這(zhe)(zhe)類畸變的(de)電(dian)(dian)(dian)壓(ya)／電(dian)(dian)(dian)流(liu)通過傅(fu)里葉分解，等效成工頻的(de)基(ji)波(bo)(bo)和若干工頻整數(shu)倍(bei)（倍(bei)數(shu)大于等于2）的(de)雜(za)(za)質波(bo)(bo)加，這(zhe)(zhe)類雜(za)(za)質波(bo)(bo)形(xing)稱為諧(xie)波(bo)(bo)。非線性(xing)負載(zai)(zai)是系(xi)統(tong)產(chan)(chan)生語波(bo)(bo)的(de)主要原因，這(zhe)(zhe)類負載(zai)(zai)一般稱為諧(xie)波(bo)(bo)源(yuan)，隨著電(dian)(dian)(dian)力電(dian)(dian)(dian)子技術的(de)發展，電(dian)(dian)(dian)力電(dian)(dian)(dian)子裝置(zhi)成為目前電(dian)(dian)(dian)網中(zhong)(zhong)最主要的(de)諧(xie)波(bo)(bo)源(yuan)之ー。

諧波的出現對公(gong)共電(dian)網(wang)(wang)來(lai)說是一種污染，它(ta)使用(yong)電(dian)設備(bei)所在的電(dian)網(wang)(wang)環境惡化(hua)，同時(shi)也會對公(gong)共電(dian)網(wang)(wang)以外以及(ji)周國的通信造成危(wei)害，它(ta)會降低系統容(rong)量：加速用(yong)電(dian)

設(she)備(bei)老化，縮短其壽(shou)命(ming)，嚴重的(de)甚至(zhi)直接(jie)損壞設(she)備(bei)，危(wei)害(hai)安全生(sheng)產；同時在不斷(duan)的(de)浪費電能，造成大(da)量經済損失。