Research On Non-topological Method Based On Equivalent Parameters Physical Constraints And Equivalent Components Comprehensiveness

Sub-grids interconnected closely in power system, the internal network’ssteady-state analysis must consider the impact of the close contact external network onit. However, due to the reform of the electricity market push forward continuously, thevoltage-grading and district-dividing feature of grid operation&management and theoutdated development of data unified platform, the internal network generally only getthe typical operating mode data of external network, but is difficult to obtain thereal-time synchronous unified data of the whole network, so it’s hard to achieveintegrated analysis for the closely interconnected sub-grids. The non-topological stateequivalent method, which estimates equivalent parameters only using real-timemeasurement data of the internal network or at the boundary buses, has become the keytechnology to ensure the internal network steady-state analysis and decision-makingeffectiveness. However, the existing non-topological methods still have some problem,such as, equivalent parameter estimates is unstable, unreasonable, external equivalentnetwork does not have comprehensive, this thesis have in-depth research on it,non-topological method based on equivalent parameters physical constraints andequivalent components comprehensiveness is proposed. The main research work are asfollows:①Multi-port non-topological static equivalent method based on equivalentparameters physical constraints is proposed. This thesis proposes the multi-port externalequivalent network considering equivalent load which based on the expansion Theveninequivalent circuit with a load, and deduces the general measurement equation of itsequivalent parameters. At the same time, considering the non-topological staticequivalent methods have prominent multiple results features, when using the leastsquares objective function for solving the equivalent parameters, as well as the problemof initial value influence the calculation results greatly, This thesis bases on typicaloperating data of external network, using the topological method considering sensitivityconsistency to calculate the typical values of external equivalent network parameters,and established the non-topological optimization model with equivalent parametersphysical constraints, analysis the estimated conditions of this model.②Multi-port non-topological static equivalent method based on the equivalentcomponents comprehensiveness is proposed. Taking into account the actual external network containing a large number of ground capacitance and reactive compensationdevices, while the existing equivalent methods can’t reflect it correctly, this thesis putforward the external equivalent network should contain the equivalent branchescomponents on the ground, to reflect the voltage and reactive power supporting roleproperly from the ground capacitance and reactive compensation devices of the externalnetwork. This thesis also retained the equivalent generators, equivalent branch andequivalent load components in the external equivalent network, and propose amulti-port external equivalent network based on the equivalent componentscomprehensiveness. This thesis deduces the general measurement equation of itsequivalent parameters, and using the typical operating data of external network and thetopological method based on component particularity representation and sensitivityconsistency sensitivity to calculate the typical values of external equivalent networkparameters, then, established the non-topological optimization model based onequivalent component comprehensiveness, and analysis the estimated conditions of thismodel. This model is suitable for the situation of the external network contains a largenumber of branches on the ground, in order to reflect the information of real externalnetwork as fully as possible.This thesis utilizes the New England39-bus system to construct cases, whichverify the proposed methods are applicable to single-port and multi-port interconnectedpower system, their equivalent parameter estimates are stable and reasonable, canreflect the effect of external network to the internal network all sidedly, can providevoltage and power support to the internal network properly when it operating modechanges, improve the accuracy of the internal network static security analysis ininterconnected power system.