Research And Application Of The500kV Substation Online Harmonic Monitoring And Analyzing System

With the increasing of nonlinear loads in the industry, the harmonic distortion in powersystems are becoming increasingly serious. The harmonic will produce great harms，such asthe grid voltage and current waveform distortion, and cause power quality to decline, affectthe safe and economic operation of the equipment. Because of the low side of500kVsubstation usually equipped with shunt capacitors, it is apt to cause the harmonic resonancephenomenon, and cause capacitor damage. Therefore, on-line monitoring of500kV substationharmonic is important.First, this paper introduces the concept of harmonic and status of harmonic-onlinemonitoring, and introduces the GB/T14549-1993standards and the utility grid harmonicIEEE519, IEC61000international standard.Secondly, a detailed analysis of the major harmonic sources and their impacts and harmson the power system is given; at the same time, this paper introduced the mechanism of theharmonic source.Again, this paper describes the harmonic analysis and harmonic monitoring method, andanalyzes the Fourier algorithm commonly used in the harmonic monitoring.Finally, this paper constructs the harmonic online monitoring system for500kVsubstation, and installs it on35kV parallel capacitor of the500kV Yandu substation, andachieves500kV substation online monitoring of harmonics.