Research On The Stability Evaluation Method Of Active Distribution Network Based On Short-term Load Forecasting

With the increasingly prominent energy problems and the development of science and technology,a large number of distributed generation(DG)access distribution networks to form the active distribution network,and DG’s access also brings some stability impact to the distribution network,which means that the need for the active distribution network stability assessment analysis,the specific research contents are as follows:First of all,this thesis presents a combined power flow calculation method for transmission and distribution network with DG.Based on the traditional method of global power flow calculation,DG’s access is fully considered and the equivalent model of distribution network is improved,which reduces the mismatch rate of the transmission and distribution grid boundary Information.Then,through the simulation analysis of the transmission and distribution system composed of western system coordinating council(WSCC)11 node transmission network and IEEE 33 node distribution network with DG,the effectiveness of the proposed transmission and distribution network combined power flow calculation method is verified.Then the stability margin of PV curve is analyzed for the transmission and distribution system composed of IEEE 30 node transmission system and IEEE 33 node distribution system with DG,and the necessity of the combined analysis of the transmission and distribution network in the future distribution network stability evaluation is illustrated by simulation of the proposed power flow calculation method.Then,this thesis constructs a new research model of the branch stability of active distribution network,on the basis of the combined power flow calculation of transmission and distribution network with DG,a new integrated stability online evaluation method of active distribution network based on equivalent nodal method is proposed,and three new branch stability indices,namely voltage collapse coefficient,overload coefficient and comprehensive stability coefficient,are established to achieve the omni-directional stability analysis of the branch of active distribution network.Then,through the simulation analysis of transmission and distribution system composed of the WSCC 11 node transmission network and a 10 node active distribution network,the feasibility and comprehensiveness of the proposed assessment method are proved.Finally,the shortcomings of load growth strategy in traditional stability assessment are analyzed.Based on the above three indicators of branch stability evaluation of active distribution network,a method of active distribution network stability evaluation based on short-term load forecasting load growth mode is proposed.Through the simulation analysis of the transmission and distribution system composed of the WSCC 11 node transmission network and a 10 node active distribution network,the accuracy and effectiveness of the proposed method for the stability assessment of the active distribution network based on short-term load forecasting is verified.