Research On Disturbance Propagation Localization And Control Method In Power Systems Based On Wide Area Measurement System

With the interconnection of regional power grids,the dynamic characteristics of power grids after disturbances is becoming more and more complex,while the frequency fluctuation range is large and presents complex temporal and spatial distribution characteristics due to disturbance propagation.The problem of system frequency stability is prominent,resulting in the limitation of local frequency measurements based control.The wide area measurement system(WAMS)can provide synchronized and fast data in real-time basis for the frequency stability collaborative control of power systems.In view of the obvious temporal and spatial distribution characteristics of frequency dynamics and the difficulty of frequency cooperative control in interconnected power grids,based on WAMS measurement and the temporal and spatial dimension,this thesis studies the disturbance propagation model,the rapid disturbance event localization method,frequency situation awareness approach and the active frequency control strategy based on the cooperation of multi-energy storage station.The specific innovative achievements are as follows:(1)It is proved that the reasons that cause the inaccuracy of the spatiotemporal dynamic model of uniform frame continuum is the uniform distribution of inertia and the inertial loss.Then,the consistency between the power grid disturbance propagation and the mechanical torsional wave is deduced and verified,and the state transition models of the elastic medium and the inertial medium in power systems are established.The Gaussian continuous non-uniform distribution model of inertial parameter is established.Based on the state transition model,the equivalent parameter expression considering the anisotropy of disturbance propagation is deduced.Futhur more,the spatial-temporal dynamic model of non-uniform frame structure continuum model is established to accurately describe the disturbance propagation characteristics in interconnected power grids.These methods provide a model basis for disturbance source location and frequency prediction.(2)A spatiotemporal feature extraction method of disturbance propagation based on WAMS measurements and the spatiotemporal dynamic continuum non-uniform frame structure model is proposed.The two-dimensional spatiotemporal features of the disturbance arrival time difference and the propagation time difference are extracted.Based on the above features,an event range identificaiton method based on the spatial-temporal correlation characteristics of disturbance propagation is proposed,and an accurate disturbance localization model of multi-label classification approach is further established.This method only uses limited measurements and local topology information to realize the accurate position of disturbance,yielding a shorter data window and faster calculation speed.(3)Based on the spatiotemporal dynamic continuum frame structure model,the modes affecting the frequency response are extracted.A method of the frequency spatiotemporal diagram construction based on the triangulation and 2D-bicubic spline interpolation and modal extraction approach are proposed.An adaptive low rank modal fusion model is further established,which breaks through the limitations of the single modality on capturing the temporal and spatial dimensions.In addition,a frequency prediction model based on an improved long short-term memory spatial-temporal network by using the encoder-decoder structure is constructed,which realizes frequency situation awareness considering spatial-temporal distribution characteristics.The problem of predicting the frequency stability margin of each spatial location of power grids can be solved.(4)A frequency stability active control method based on the real-time measurements of WAMS and the cooperation of multi energy storage power stations in regional power grid is proposed.The mathematical relationship between active power output of energy storage power station and regional frequency variation is revealed.For the scenario where the frequency stability problem is predicted,an active control method of ladder power support based on the energy storage power station in cooperation with WAMS measurements is proposed.Further considering the reserve capacity of energy storage power stations in the region,the cooperative control strategy of adaptive power support of energy storage power stations in different regions is proposed,which solves the problem of frequency cooperative control of interconnected power grid and improves the margin of system frequency stability.