A Study On Evaluation Of Residual Current Protection Status In Low Voltage Power Network

Residual current protector has been applied to low voltage distribution network comprehensive promotion, but due to various factors of its quality, installation and environment, management difficulties and other factors, the residual current protector tripping and malfunction occurs frequently. So the power enterprise proposed the building of the residual current intelligent inspection system, in order to strengthen the supervision of residual current protector, and ensure reliable operation of the residual current protector. Intelligent inspection system generally consists of a portable residual current protection tester, residual current protection backstage management database and other modules. Field test instruments identify the number of residual current protector and measure its action characteristic parameters online, then test data stored automatically and transmission to the background database. The test data provide an important basis for the residual current protector operation state evaluation.Currently power system use electrical equipment maintenance management model widely, the paper studied the evaluation methods for running the distribution network residual current protection device in depth, developed residual current protection status evaluation method for intelligent data logging systems. It can achieve evaluation and early warning of residual current protection status, it is very important to ensure the safe and reliable operation of residual current protection device and electricity supply.This paper analyzes the principle structure of various types of residual current protection, because the residual current protection configuration mode, different wiring grounding system of residual current protective devices, and various failure modes and mechanisms generated. On this basis, to determine the various parameters to characterize the residual current protection device running state, including the current action, action time, test trip condition, environment and climate. In order to make the index weight is more close to the residual current protector for the real status, this paper uses fuzzy AHP to build the hierarchy analysis and evaluation system, all kinds of state information of comparison, the index weights of elements. Finally, the residual current protector comprehensive evaluation method based on fuzzy comprehensive evaluation, the method considered to reflect various state information of residual current protective device running state, and establish reasonable evaluation set, then by expert staff and other co-ordinating state evaluation the subjective and objective factors to rate each indicator to determine the membership of each evaluation set reuse assigned method, then the principle of the final evaluation of the state of residual current protection device based on the maximum degree of membership. Applications show that the method can effectively evaluate the status of the residual current protection.