Research On Status Parameters Online Monitoring And Fault Location Method For City Distribution Lines

"Smart Grid" is the latest trend of electric power development and change in modern times. As an important construction content of "smart grid", the power distribution network on-line monitoring and fault location use a variety of monitoring technologies to search the hidden trouble of dynamic early warning and fault point location so that we can avoid the accidents of power grid and put an end to the occurrence of blackout.Based on the analysis of on-line monitoring and fault location technology of the transmission lines, this paper briefly describes the common failure types and the causes of the power cables, then treat the highest frequency of single-phase earth as the main research object. First of all, using Wireless Sensor Network to construct the on-line monitoring system of the distribution power network, which can monitor multiple indicators of the cable lines on-line and dynamically assess device state.Then the paper expounds the principle of fault traveling wave, the transmission and the introduction of several traditional methods that are based on traveling wave. According to the advantages and disadvantages of traditional methods, a new kind of traveling wave location method is improved, which is called three-terminal method. This method need not to consider wave velocity which is unstable, and simplifies the operation steps and improve the locational accuracy.Based on the strong ability of wavelet transforming on the analysis of transient signal, this paper puts forward to use Haar wavelet to analyze the fault traveling wave, and establish the MATLAB simulation and modeling analysis for 10 kV distribution network power line. Paper finally gives a series of steps for fault locating:1.Locate the fault branch2. Locate the faulty section3. Locate the fault phase and locate the fault pointThis paper also analyzes the factors that can affect the positioning error. The simulation results have fully affirmed the feasibility of three-terminal method and wavelet transform in the fault location of power distribution.