Study On The Operation Risk Of 500kV/220kV Electromagnetic Loop In Shenzhen Grid

High and low voltage electromagnetic loop network to improve the flexibility and reliability of the system,but also to bring the wind direction of the system safe operation.In the current power structure is not mature or special operational needs of the circumstances,in order to meet the load demand,improve power supply reliability and economy,power quality,power may take the high and low voltage electromagnetic loop operation.But in practical applications,the electromagnetic loop network must be calculated and checked to ensure that the system runs safely and stably,and to reduce the risk of system operation.Combined with the engineering practice,on the operation mode of 500kV/220 kV electromagnetic loop network may exist in the summer of 2015 Shenzhen power grid operation mode,using BPA simulation software to carry out the research from three aspects of transient stability of Shenzhen power grid,the risk focus on the risk of short circuit current and thermal stability risk,the main research contents include: 1)reviews the Shenzhen power grid in 2015 summer peak load demand,there may be four kinds of electromagnetic loop operation,a detailed analysis of the different electromagnetic loop network scheme of power supply reliability,flexibility and power supply capacity,compared with the four different in structure and power supply scheme;2)for electromagnetic loop network structure in different ways,using the electromechanical transient simulation tool,calculation and analysis of the time limit of Shenzhen power grid with three-phase fault,and the fault and the provisions of the Shenzhen power grid clearing time comparison,evaluation compares the transient stability risk of different mode of electromagnetic loop network structure;3)for electromagnetic loop network structure in different ways,using computational tools of short-circuit current,short-circuit current and short-circuit capacity of Shenzhen power grid fault busbar three-phase fault calculation under,and Shenzhen power grid short-circuit current control requirements are compared,evaluate the short-circuit current of electromagnetic loop network structure risk in different ways;4)for electromagnetic loop network structure in different ways,using the power flow calculation tool,calculation and analysis of the load rate of normal operation state and the N-1 state of the line,and the results were compared with the thermal stability of Shenzhen power grid current,evaluate the thermal stability of the electromagnetic loop network structure risk in different ways.Through the comparative analysis of transient stability,short-circuit current and thermal stability of the three risk,finally obtains the Shenzhen power grid 500kV/220 kV electromagnetic loop operation proposal,protection of Shenzhen power grid safety,reliability and economic operation,provide technical support for dispatchers.