A Joined Quasi-Steady-State Power Flow Calculation for Integrated Energy Systems

Abstract

The network storage capability of district heating systems and gas systems can provide a considerable flexibility in integrated energy systems, increasing the use of volatile renewable energy generation. But the stronger the single energy systems are linked the more complex their operation becomes due to their increased interactions. To ensure a secure and reliable system operation while using the full potential of integrated energy systems, these interactions must be analyzed. Existing power flow calculation methods, however, assume a steady-state behavior of all energy systems in the integrated energy system, neglecting the network storage capability. Hence, this paper presents a joined quasi-steady-state power flow calculation method for integrated energy systems. Our method introduces the dynamic behavior of the district heating system arising from the temperature propagation and the dynamic behavior of the gas system due to the gas compressibility and propagation of hydrogen. In a comparison with a steady-state power flow calculation we show the considerable effect of the network storage on the operation of an integrated energy system. As our method enhances existing steady-state power flow calculation methods, it can be easily used for the same use cases but allowing the full potential of integrated energy systems to be investigated.

Keywords

• Quasi-steady-state
• integrated energy system
• power flow calculation
• Newton-Raphson method
• gradient method