Research On The Matters Of Relay Setting Coordination For Distributed Network

Relay setting coordination is the basis of secure operation of power grids, it is the guarantee for relay device to isolate faults from the grids in time and to avoid the occurrence of fatal accidents, so its research is of tremendous economic and social benefits. Reasonable setting calculation plays an important role to improve the operating performance of the protection device. The accurate and reasonable calculation is the guarantee for the quick, accurate and reliable action of the protection device. According to the characteristics and special requirement of protective relaying setting in district power network, combining with the specific issues in the software development, this paper present coordination theory research, coordination automation technology and the settings verification system.First, in aspect of the setting theory, considering the characteristics of regional power grids, this paper analyses the main forms of the protection of district power grids, present the calculation principle of zero-sequence current protection , grounding distance protection, and some other content, such as the influence of line mutual inductance to the zero-sequence current protection calculation, the abuses impact of zero-sequence current protection, the merits of detective impedance method, the setting of two special kinds connecting lines, and so on.Secondly, in aspect of relay coordination automation technology, this paper analyses the characteristics of the operation mode of the district power grids, and two problems in searching for the operation mode are pointed out: (1) failure for searching for the unfavourable mode; (2) repeating the same line breaking when searching. The methods to solve these problems are proposed which are based on the current distribution coefficient, the disturbance area and the close degree. This part of research content has guiding significance to improve the efficiency to the computer setting.Finally, the settings verification system is present. The verification structure, principle, operation mode of the system and the calculation process are proposed. At last two problems are studied: (1) the arithmetic of quickly attaining protection range based on node impedance matrix; (2) obtaining methods of on-line data for setting verification.