Optimization Study And Analysis Of Influencing Factors For Erosion Diagnosis Method Of Grounding Grid

The security and reliability of power system is affected by the safe operation of substation, and the complete and reliability of grounding grid is the security of substation. The pressure conductors which constitute the grounding grid is buried in the ground, the situation that make the bad electrical connection in pressure conductor is caused by weld bad and the effect of electric power of earth short-circuit current, especially severe corrosion by several years. A earth short circuit current may takes serious loss to economics and impact to society. So, testing the break point and corrosion situation, and identified and excluded the hidden fault, prevent the harm by improper grounding is particularly important.Currently, experts studied for principle and mathematical model of diagnosis of grounding grid, but lack of practical engineering. There is a method which based on Tellegen theorem, principles of diagnosis and optimization method, it can diagnosis the corrosion without power failure and excavation of a large area to grounding grid, only need to measure the conductor resistance value. This method is practical in engineering. But when do the field test, the result can be influenced by inaccurate drawings and offsetting of deflectors and interference.This article mainly study these contend for theory and method of erosion diagnosis of grounding grid.①Write software for erosion diagnosis of grounding grid by VC, and adds on data port. The software achieved functions that automatic ID of branch and nodes in grounding grid, automatic input correlation matrix, measurements direct input to computer and so on. It greatly reduced the workload.②There is distinctive between the design and the topology in the actual grounding grid. This article made simulation for the change of conductor length and the loss of conductor, from the consequence it get the main influence is the increase of the quantity of pseudo-fault, through the plus measurement of serious corrosion it can decrease this influence.③In the problem of influence of down led line deviation, the margin of down led line deviation is divided into 4 ranks, the conclusion is that when the margin of deviation increased, the increase of multiple resistance of corrosion slip will reduce, the quantity and the increase of multiple resistance of pseudo-fault will increased. ④Taking the conductor in cable channel into the grounding grid erosion diagnosis, analysis through the simulation, the conclusion is that the conductor in cable channel access into the main grounding grid will reduce the increase of multiple resistance.⑤Summarized the shortage in previous diagnosis and tests, improved the measure method through analyzing, this method made the little effect of the measurement data reduced, and reduced the plus measurement work.⑥The substation grounding grid erosion optimized diagnosis experiments were done in practice in Shaoguan, Shantou, Zhaoqing, etc. The result of excavation shows the diagnosis method can effect diagnosis the location and the corrosion of fault slip, reach the requirements of engineering practicability.