In the modern power system,acute fluctuation of load lead to great difference of wave crest and trough,abundance non-linear load make severe aberrance of current and voltage wave.

• 现代电力系统中，负荷波动剧烈使负荷峰谷差值很大，大量的非线性负荷使电流、电压波形畸变严重，这些因素使电能计量误差显著增大，并使计费不合理。