Study On Short-circuit Current Analysis And Application In Industrial Electric Power Network

In recent years,with the continuous increase in the enterprise grid load,the network structure is gradually increased, the power projects continue to invest to ensure the safety and reliability of power supply. The ring network is increased in gradually increasing power structure, reducing the electrical distance, so that the short circuit current level is improved. The power projects are also invested,considering the tension and the effective use of energy aspects, there have been increasing the unit capacity of geneator. The outside network access point is also increased. These will directly cause a short circuit current increase. The trend of short-circuit current increasing is more and more serious, together with its stability issues in the power system planning and operation of the main issues to be considered.At present, Tianjin petrochemical network is currently running for a second phase (the installed capacity of generating units is 100MW), In order to meet the 100 million tons / year ethylene project , the new third grid is constrocted (generating units with an installed capacity 300MW). In addition, the sinopec network will have a new external power grid (the JinJiaoXi West Substation) access. After the completion of Phase III network, enterprise network load and installed capacity have a substantial increase, power structure is more complex. The short circuit current level is detected to check circuit breaker interrupting capacity. Therefore, this project of great significance in short circuit current calculation, checking circuit breaker interrupting capacity, solving the excessive levels risk, ensuring the stable operation of corporate network security.In order to check Circuit breaker interrupting capacity, the current status of short-circuit current calculation and it's application is analysised at home and abroad, then the current flow of domestic and international programs in consolidated limit measures is described. This paper also has a detailed analysis of short-circuit current calculation of the basic principle, theoretical analysis and simulation in the Point of maximum short circuit current . Then the mathematical modeling of Tianjin Petrochemical grid is built, short-circuit current is calculated to check Circuit breaker interrupting capacity. Finally, the integrated current limiting is mesaures research on how to select the best program of comprehensive economic limit measures.