Research And Development Of Protective Relaying Simulation In Dispatcher & Operator Training Simulation System

The State Grid Corporation of China is intensifying its management in human,financial as well as resource,and systemizing its planning,construction,operation,recondition and production.The formal management model for substations,which separated regulation and control and decentralized supervisory,can no longer meet the grid’s requirements of the large operating system.It is necessary to have in-depth research in dispatching technologies,which support system specification,and platforms,which support and help apply key technologies,in order to support the integrated operation.Therefore,there is need to establish a highly efficient,comprehensive,systematic dispatcher training simulator to support the construction of the large operating system.The key of the simulation system is to establish a detailed model of all the secondary equipment in all substations included by the range of adjustment,realize the full-scale simulation based on the mechanism of the secondary system,and ensure the integrity and authenticity of system information under accident circumstance.Relay protection device is the key of the secondary system.The protective relaying simulation is significant for training dispatchers’ capabilities of handling accidents and guaranteeing the safe and stable operation of the grid.This paper briefly introduces the domestic and foreign status quo of protective relaying simulation technologies.It also summarizes the current problems and obvious drawbacks of three existing methods,which can’t meet the requirements of large grid’s operation.The paper compares and summarizes the three traditional simulation methods.The logical reduction simulation can provide information of protective device by topology analysis and safety operation rules without calculation of malfunctions.Although it is fast,it cannot be achieved under multi power and complicated logics.The quantitative comparison simulation need to calculate the changes of electrical quantities according to malfunctions of grid and then impel the protection.Although the result is accurate,it overly relies on the results of operation and the workload of maintaining parameters is heavy.Case study can come to the result off-line first and then take into actions.However,this method is inflexible.In this paper,a new protective relaying simulation method,which is direction-distance method,is brought up by considering the principles of direction and distance protection.Based on the topological analysis of logic,the direction-distance method combines the advantages of logic judgment and quantitative comparison methods,and introduces the short circuit power,which makes up the problem that the simple logic method cannot judge the direction protection action.Comparing with quantitative comparison method,the value of the impedance is replaced by the malfunctions equivalent distance,which simplifies the calculation of the protection value.It can realize almost all the malfunctions of complex power grid and do not have to maintain a large number of fixed value parameters.Direction-distance methods combines the strengths of logic judgment method and quantitative comparison method,which is especially suitable for protective relaying simulation.This paper elaborately illustrates the theoretical basis of the direction-distance method and its range of application as well as simulation procedures.It also introduces how to realize the simulation of the circuit,transformer,unit and busbar protective device.Finally,the correctness and practicability of the results of this paper are verified by the processing of the permanent A-phase short-circuit malfunctions in the vicinity of the Yongde line of 500kV Desheng Station.