Risk Assessment with High Distributed Generations Penetration Considering the Interaction of Transmission and Distribution Grids

With the integration of distributed generations and expanding loads, the uncertainty has become significant in power systems. To achieve exact evaluation of the operation security, a risk based assessment method considering the coordination of transmission and distribution networks is proposed in this paper. The probability models of power system components are proposed to approximate the uncertainty. To achieve voltage and branch power flow, global power flow (GPF) is calculated using a master-slave-splitting method to consider the coordinated operation of transmission and distribution networks. The risk assessment index is established considering both voltage and power flow security. A risk assessment process is proposed by using Monte Carlo method. The proposed risk assessment process is tested in an integrated transmission and distribution test system. The results of numerical simulation reflect the validity of the proposed assessment method.