Research On Static Equivalence Method Of Power System Based On BPA Data

The large-scale development of China's UHV DC transmission project and its related innovative technologies has promoted the interconnection of China's regional power grids,and the systems are linked more closely.It has also brought tremendous challenges to the power system's analysis and calculation process.Considering the mutual influence of interconnected systems,the whole-network integration analysis method will be difficult to guarantee system analysis speed and accuracy due to the limitations of the actual system scale,regional management system,and information exchange security.In order to solve this contradiction,related scholars proposed that the static equivalence method simplifies the system analysis process by retaining only the research system equating the external system.Under the background of interconnection of large-scale power systems,it is of great significance to study the system static equivalent model and method for large-scale power grid analysis and decision-making.From the perspective of the actual power system analysis and calculation,this paper studies the static equivalent models and methods of AC system,AC/DC system and UHV DC system in hierarchical connection mode according to the actual engineering BPA network data.The specific work of this paper is summarized as follows:Firstly,the paper introduces the specific implementation process,advantages and disadvantages of conventional Ward equivalent method,extended Ward equivalent method and the equivalent method which considerring sensitivity,and proposes a new equivalent method by comprehensively drawing on its advantages.Comprehensively drawing on its merits,a new equivalent method was proposed.The new static equivalence method is not constrained by the boundary node type,and the accuracy of the system reactive power response is ensured by constructing an external equivalent generator network.Then the paper studies the principle of BPA-Matpower data conversion and develops the conversion interface program to complete the extraction and transformation of the actual engineering BPA data.Based on the completion of the data conversion,the system basic element model and the corresponding processing method are studied according to the static equivalent requirements.The basic flow chart of static equivalent method applied to the power grid engineering data is summarized,and the correctness of the static equivalent model and method proposed in this paper is verified by the simulation of different example systems in different operating modes.Then,to solve the probem that the AC/DC system can not form a uniform node admittance,the anthor draws on the ideas of AC and DC power flow calculation alternate iteration method,and the DC system is equivalent to the AC branch circuit,and then the AC equivalent equivalent method is used to complete the static equivalent process.Finally,on the basis of the static equivalent model of a simple DC system,according to the basic model and characteristics of the DC layered system,the method to solve the equivalent AC branch model parameters for static equivalent of the UHV DC system in hierarchical connection mode is deduced.The UHV DC system in hierarchical connection mode is replaced with an equivalent AC branch to complete the static equivalent.Based on the premise of constant DC transmission power in a certain period of time,this paper carries out static equivalent simulation of the actual simple DC system and the UHV DC system in hierarchical connection mode,and verifies the validity and correctness of the static equivalent model and method of the AC/DC system.