Research On Safe And Economic Operation Of Regional Power Grid Containing Wind Farms And Photovoltaic Plants

In this thesis the following issues related with transient stability and economicoperation of power system containing wind farms and photovoltaic plants are researched.They are the output of large wind farms and photovoltaic plants modeling, transientstability calculation and probabilistic optimal power flow calculation of power system. Inthe paper, new methods are applied to the time domain simulation and OPF calculation ofpower system including wind farms and photovoltaic plants. The accuracy and validity ofproposed methods are tested on IEEE bus systems and are more suitable to the timedomain simulation and OPF calculation of power system including wind farms andphotovoltaic plants.This paper builds wind speed model by Copula function and uses rank correlationmatrix to measure the correlations of wind speeds. The wind speed model can measurethe wind speed more practical and make the analysis of transient stability and OPFcalculation including wind farms more close to the reality.This thesis calculated the transient stability probability statistical characteristics ofpower system containing wind farm by transient time domain simulations based on thecombined Copula and Stochastic Response Surface Method. The case study on IEEE39-bus system and Yunnan Power Grid showed that the proposed method provides aneffective modeling analysis method to calculate the transient stability probabilitystatistical characteristics in power system containing wind farm and it is a reference tosystem transient stability analysis.Digital Nets method which has equidistributed sample values is applied to improvethe sample values coverage of random variables input spaces. Then this method is used tothe OPF calculation of power system including wind farms and photovoltaic plants. Theaccuracy and validity of proposed method are tested on IEEE30and IEEE300bussystem. The simulation results show that the proposed method has the advantages of fastcomputation and high accuracy and it can estimate the probability distribution of theoutput random variables and deal with the uncertainties in the electricity market.Sobol sequence which has equidistributed sample values is applied to computetransient stability of power system, obtaining accurate result by less simulation times.Meanwhile, Mixed-Copula is applied to measure the correlation of wind farms and thecorrelation of photovoltaic plants. Then judging whether the selected Copula is suitableor not by calculating the squared Euclidean distances to empirical Copula. The case studyon IEEE39-bus system shows the effectiveness and applicability of the method.The proposed modeling and calculation methods in this paper provide new ways fortransient stability and OPF calculation including wind farms and photovoltaic plants. They also provide effective references for power system designing as well as the systemsafe and stable operation.