The Fault Diagnosis And Simulation Of Running Cable In Power System

This paper first focuses on power cable with XLPE insulation. It analyzes the importance of diagnosis for cable insulation, introduces the advantages and disadvantages for supplying power using power cable, and discusses its technique level all over the world and its developing trend of the insulation diagnosis for XLPE power cable. Based on this, the features signal and research of simulation of insulation breakdown fault, which is the key substance of this paper, is put forward.Firstly, this article presents the reasons and types of power cable faults form points of view of both macroscopic and microcosmic. Form the point of view of macroscopic, this paper get analyses and statistic on the reasons and location of power cable faults, and set forth appropriate to keep away measure. Based on this, this paper not only analyses the aging mechanics of power cable insulation, but also make further study on the generation and evolution of factors aging insulation. Secondly, introducing and comparing insulation diagnosis methods home and abroad, this paper presents the method of insulation diagnosis using grounding current signal by analyzing power cable features. Thirdly, the article puts forward shortages of field tests defined by national standards, and demonstrates necessity of online monitoring. At last, by founding simulation model, this article make detailed analysis for the electrical relation of power cable insulation at the aging to breakdown process, and mostly completes items as following: a. this paper successfully gets the breakdown process of cable; b. this paper analyses the relations between grounding current and insulation resistance, between grounding current and insulation capacitance and between grounding current and loss feature at different voltage and different load cases of both single-phase and three phase cable; c. this paper proves the affectivity of grounding current for insulation diagnosis.Simulating and analyzing insulation local deficiency of power cable, this paper presents a kind of insulation diagnosis method based on grounding current, and puts forward three periods form aging to breakdown for cable insulation according to simulation results, thereby offering favorable theory basis and practical experience for applying better cable insulation diagnosis and safely, conveniently and quickly eliminating cable faults.