Transmission Interconnections Identification for Electricity System Considering Impacts of Natural Gas Systems

The increasing interdependency between power system and natural gas systems, making the energy transaction and operation conditions of power system more complicated, threatens the security and reliability of power system. Transmission interconnections play a crucial role in the propagation of major power system disturbances. Understanding the impact of natural gas system on the transmission interconnections is important for enhancing monitoring and taking appropriate actions. This paper proposes a transmission interconnections identification method considering the impact of natural gas system. The criticality index is constructed to rank the critical transmission lines consisting of the transmission interconnections by simultaneously considering generator-load energy transaction and line-line power flow transferring, as well as topological characteristics of the power system. Furthermore, the self-organizing feature map neural network model is used to identify transmission lines with similar power flow components of the selected critical transmission line to form a transmission interconnection. Specially, a co-optimization model of interdependent natural gas-electricity system is proposed to derive energy transaction between generators and loads, and power flow transferring among transmission lines. Numerical results on the 24-bus electricity/20-node natural gas interdependent system illustrate effectiveness of the proposed method against different operation conditions.