气体放电灯使照明供电中线电流超大的理论分析

Theoretical Analyses on Greater Neutral Currect by Gas Discharge Lamps

本文分析了大量采用气体放电灯照明时，三相对称电路和多种典型的不对称电路。拍摄了这些电路的中线电流波形。分析这些波形可知： （１）即使三相负载完全对称，中线电流仍是满载相电流的３２．７％。 （２）典型的不对称情况下，中线电流大于满载相电流。 （３）若出现电路结构变化，中线电流可能大于相电流的两倍。 （４）大量采用气体放电灯的三相供电电路的中线电流不仅比相同情况的线性负载的中线电流大，而且高次谐波丰富，是一个新的谐波源。 这些分析及实验数据对照明供电设计及电缆制造厂家都有实用价值。

In case of the discharge lamps some triphase symmetrical circuit and varied unsymmetrical circuit are studied. According to the analysis of experimental data and the neutral current waves, some results are found as follows: 1. The ratio of the neutral currenl to the full-load phase current ts 32. 7% even if the triphase load is totally symmetrical. 2. The neutral current is still larger than the full_load current on the condition of typical tin symmetrical circuit. 3. If the circuit construc-tion is changed , the neutral current will be twice as large as the phase current. 4. There are many high4requency harmonics in the neutral current,and in such cases it is a harmonic source. These analyses and the experimental data may be of great value to the illuminative power-supply design and the cable manufactary.