The new research on harmonic assessment model of power system

With the establishment of the power market and great increase in demands of electric energy in China, the importance of the power quality has became more and more evident in electric industry. In recent years, plenty of nonlinear impact loads have been connected to electrical network which caused voltage distortion and the decline of power quality. So, harmonic pollution has become a prominent problem in modern power grid. We must assess the harmonic current which through common connection point and caused by electrical equipments before they are connected with the electrical network. In this paper the methods of consumers´ harmonic measurement and assessment are expounded, and the computational conditions and meanings of parameters of the formula for consumer harmonics index distribution are introduced. Followed, we will analyze the actual timing characteristics of harmonics and finally I will put forward the harmonic voltage and current assessment model which including four elements of the power quality assessment including process, time combinations, phase combinations, and index definition.