Grounding Grid's Numerical Emulation And Computation Research

Grounding system of power plant and substation is the fundamental assurance and significant measure to maintain the electrical power system operating reliably and ensure operators and electric installations safety. Now, according to electrical power system's development, its voltage level is higher and higher and system capacity is bigger and bigger. Under these circumstances, the traditional design calculation method of using empirical formula is no longer to satisfy the modern request. Modern computer's nature is better and better, which supplies a massy base for numerical method's application in the grounding grid's design and computation.This thesis introduced the basic principle of numerical computation, and did numerical handlings to satisfy the need of computer programming. Based on the job of above, we manufactured the numerical computation software using the object-oriented technology. This software's interface is friendly, and its operation is simple and convenient. We can use this software to compute dispersive current of minute segments, grounding resistance, space point potential and so on. In order to inspect and verity the correctness, the thesis supplied a lot of computing instances of various grounding grids, and compared the computed result with other persons'.A few significant parameters of grounding grid have much influence to numerical computation's precision, and so in the thesis we carried out very much computation and theoretical derivation using the software. Grounding electrode's equivalent radius and grounding grid's depth both have little influence to grounding resistance and so on. Short-circuit current which flows into the grounding grid is a significant parameter to compute space potential rise and touch potential difference, so we can use simplified equivalent method to obtain a more precise result. Because soil resistivity has an important effect to grounding resistance's computing precision, we need to measure it correctly and then handle it. In order to calculate grounding grid's relating parameters of multilayer soil structure, the thesis deduced an equivalent soil resistivity of multilayer soil structure, and supplied some computing instances. Compared with short vertical grounding electrodes, long vertical grounding electrodes have a better effect to reducing grounding resistance and increasing grounding grid's safety. In this thesis, we did much relating calculation and analysis, and then obtained any arrangement method of long vertical grounding electrodes which has any guiding value to the grounding grid's design.