Integrated energy systems (IES) are under development to accommodate the widespread penetration of renewable energy into power systems. The universal utilization of coupling components makes the connection between power grids and heat grids even closer. This paper applies energy flow calculations to planning problems and explores a method for selecting coupling components in the integrated electrical and heating systems. This process is based on the analysis of energy flow distribution and the comprehensive indexes

which include operation cost and the penalty cost of wind curtailment and solar energy curtailment. Besides

a selection method of coupling components installation locations based on energy flow calculations is provided. At last

an IES with 5 electrical buses and 5 heating nodes

and a 9-bus electrical power system with a 31-node heating transmission system are chosen to study the specific application problems in detail as well as to elucidate the effectiveness of the proposed method. It turned out that the relevant coupling components and their positions can be selected according to the indexes obtained by integrated electrical-hydraulic-thermal calculation. This proposed method is conducive to the planning of integrated energy systems.