Studying Of The Reactive Compensation Capacitor Harmonics Over-load

With the non-linear load increasing year after year, the harmonics pollution of the power system is increasingly serious. It brought the disadvantageous influence on the reactive compensation capacitor. It causes the harmonics current to enlarge, harmonic over-load, a short time use and damage indeed. Thus it can't compensate availably reactive compensation. It also leads to the decrease of power factor and the increase of line loss. And it wastes the investment in the capacitor equipments. The more serious is that the common function of capacitor and the system parameters will cause resonance, which will make capacitor appear over current and over voltage and endanger the safety of the electricity equipments and the power system operation.This article analyzed the harmonics over-load and the heat effect of capacitor. The more the times of harmonics is or the larger the frequency is ,the more heat it will give.The capacitor's influences on the system impedance are analyzed. The impedance changes with the frequencey of harmonics resonance . Over the resonance frequency the resonance shows capacitive characteristic , while below the resonance frequency it shows inductive characteristic . The capacitor will still cause harmonics amplification in power system , making it produce over current and over voltage.With analyzing capacitor's overload capacity , the limits of the harmonics' over-voltage and over-current are fixed according to the national standard (GB/T 11024.1—2001). So the relationship between the harmonic voltage and the rated voltage is get out.Through analyzing the capacitor's overload capacity, the calculation methods of setting for over current and over voltage protection are put out. Particularly on the...