Research On Transient Stability Assessment Method Based On Support Vector Machine With Pinball Loss And Port Energy Function

Transient stability assessment(TSA)has been being an important task to ensure the secure and economical operation of power systems.With interconnection of large-scale power grids,electricity market reform and growing presence of large-scale intermittent renewable energy,the dynamic behaviors of the power systems are becoming more complex and difficult to be controlled.It is necessary to study the TSA online analysis method which satisfies the current operating state and is beneficial to the complicated grid scheduling.In this paper,Support Vector Machine with Pinball Loss(Pin-SVM)and port energy function are used to transient stability assessment in bulk power grid.The main work of this thesis is summarized as follows:(1)Aiming at the problem that the traditional support vector machine is susceptible to the critical stability of the system during transient stability assessment.This paper proposes a novel TSA method using Pin-SVM.A group of system-level and projection energy function classification features are first extracted from the power system operation parameters to build the original feature set,such as average mechanical power,initial rotor acceleration,system shock,projection speed,projection acceleration and projection kinetic energy(PKE)and so on.Furthermore,a feature selection approach based on maximal Relevance and Minimal Redundancy(mRMR)criterion is employed to evaluate the classification capability of the original features for feature selection.Then,feature sets are mapped to a higher dimensional space and the TSA problem is then transformed into a linear classification problem through the Pin-SVM that makes the TSA more robust and accurate.(2)Aiming at the problem that the traditional energy function is susceptible to the influence of the system model.The energy function is reconstructed after the network topology changes.This paper proposes a novel TSA method via port energy function.The port energy is first described as the function of port state variables and control variables,then the port energy of VSCHVDC is formulated.This approach can avoid formulating energy function with the complex internal controls of VSC-HVDC,and the port energy can be extended to any power electronics devices.Furthermore,iterative potential energy boundary surface(IPEBS)is employed to TSA.With the aid of the dot product criterion to determine system instability,a maximum potential energy is searched on the instability of rotor angle's swing curves as the critical energy.