Research On Power Quality Problems And Their Countermeasures Of Nan’an Power Grid

Due to the great progress of the national economy and science and technology,as well as the remarkable improvement of the social productive forces and the consumption level,the stability and the quality requirements of the customers are becoming higher and higher.With the wide application of a large number of new power electronic devices in various industries,nonlinear and fluctuating loads in power systems are common,and the power quality is not optimistic;In addition,the advanced high-precision sensitive equipment is greatly affected by the power supply quality of power system,any weak disturbance will cause the decline of working performance.Therefore,it is of great significance to study the power quality and its countermeasures.Firstly,the power quality of Nan’an power network is studied,and a large number of large rectifier device,intermediate frequency furnace,high frequency furnace,refining furnace,electric arc furnace and other interference equipment,which have serious impact on urban power supply network,are found.In addition,the use of new appliances causes serious power quality problems in the distribution system of residential areas,shopping malls,office buildings,hospitals,and other places.Then,field test of the main line of Ximei substation and Xiangyun substation has been done,the test data shows that the power supply circuit have many power quality problems,such as voltage and current harmonic,voltage fluctuation and flicker,three-phase voltage unbalance,voltage deviation exceeds standard and so on.A simulation analysis is made on the Ximei substation,including the analysis of the impact of harmonic on capacitor,the harmonic resonance of the system and the switching overvoltage and overcurrent of capacitor banks,comprehensive and accurate assessment of the impact of various power quality problems is carried out.Finally,reasonable measures,including the installation of filter,the use of reactive power regulation device,the installation of reactor and so on,are put forward for all kinds of power quality problems.And the compensation effect of the filter and reactor is simulated.The simulation result shows that the power quality of the power system is significantly suppressed,which significantly improves the power quality of the power grid.