The Analysis Of Disturbance Loads Qualities And It’s Influence On Power Quality As Well As The Control Method In Ningde Power System

The disturbance loads in the electric power system propose high requirement for the power quality. When the disturbance loads are connected to the power system, they not only result in power quality problems,but also impact on system stability and measurement. Therefore, it has profound theoretical and practical significance to analysis the characteristics and the influence on power quality of various interference loads, and to search reasonable, economical solution.At present, the main factor affecting on Ningde power system is the harmonic wave produced from steel factories. There are many steel factories in Ningde in which the electric-arc furnaces and intermediate frequency furnaces are used in large quantity. So, it is important to analysis the characteristics of various of disturbance loads and to find a efficient method to improve the power quality of Ningde electric power system.The main works of this thesis are as follows:1. Analyses the present power quality and disturbance loads of Ningde power system. Classify the disturbance loads in Ningde according to their electrical characteristics and the type of user.2. Establishes the analysis load models for the special loads, and analyse the effcet on power quality by simulating. So the simulating models of electric-arc furnace and intermediate frequency furnace are established by matlab, which explains the origin of harmonic wave.3. Proposes the method to restrain the harmonic wave level in power system according to the outcome of simulating. Based on the facts in Ningde power system, the harmonic wave filter devices are designed to decline the harmonic wave, and the harmonic wave control strategy is presented.4. Proceeds the comprehensive analysis of the influence on the PCC with multiple disturbance loads. In this paper, taking the Xiwei transforms station as example, it proves the fact that even the harmonic wave level is under the limit of allowable value for single disturbance load origin, the final harmonic wave level at PCC will exceed allowable value if multiple disturbance loads are connected to PCC.