A System On Disturbance Property Load Assessment Based On Virtual Instrument

At present,disturbing load has become an important part of power system. It is necessary to identify disturbing sources and evaluate comprehensively the performance of disturbing load so as to judge who should take responsibility for causing power quality problems and solve contradictions and disputes between power utility and customers.Initially the paper analyzes the electricity characteristic of typical disturbing loads and summarizes the characteristics of harmonic current,negative sequence current and voltage fluctuation at PCC caused by disturbing loads. After comparing the existing identification methods, a method which can be implemented easily is selected to identify the disturbing sources,such as harmonic, flicker and sag. Following this, the disturbing load is evaluated by genetic projection pursuit method considering three indexes, including negative sequence current, power factor and harmonic current. Finally, with combination of C++, LabVIEW and SQLServer, a system is developed to analyze and evaluate the disturbing loads which can change, storage, inquire and evaluate the power quality data with Pqdif format.