Integrated quasi-steady-state energy flow algorithms and flow distribution factors for future integrated energy systems (QUESTIES)
Final Report Abstract
The increasing share of volatile renewable energies in the electricity supply, the shutdown of conventional power plants and a lack of power lines lead to challenges in the electricity grid. The grid is increasingly lacking flexibility to compensate for fluctuations in generation, which puts grid stability at risk. Integrated energy system (IES) (here: electricity, gas, district heating) can be used to increase flexibility. Within these systems, energy can be moved between infrastructures. Since the interactions and dependencies between the systems increase with increased coupling, an independent view of the networks is no longer appropriate. This can lead to threats to network stability being shifted between the networks and the overall system becoming more unstable. In order to ensure reliable and safe operation of an IES, it is necessary to determine the mutual influences on the grid status and to analyze the influence of generators, coupling technologies or consumers on the grid status. The Quest-IES project therefore developed sensitivity factors that can be used to analyse the effects of power changes on the power flows of all three energy systems. Furthermore, a coupled quasi-steady-state power flow calculation was developed that can map the dynamic gas and district heating network behaviour. The calculation maps the temperature distribution in the heating network as well as the hydrogen distribution and the effects of gas compressibility in the gas network. A validation with analytical solutions and verification with existing literature results shows a very high accuracy of the developed calculation in the depicting of the dynamic behaviour in the heat and gas network. Detailed analyses show that this dynamic behaviour has a strong impact on the power flows in the IES and on the operation of coupling plants. The investigations thus showed that the frequently used stationary power flow calculations represent a strong simplification of the physical behaviour of the IES. Sensitivity factors were derived on the basis of the quasi-steady-state power flow calculation using the PTDF approach. These show a high computational efficiency and are on average ten times faster than a power flow calculation to estimate the effect of a power change on the power flows in the IES. However, the quality of the results compared to a power flow calculation depends on the grid topology, the load and generation situation, the location of the power change and the amount of the power change. Despite the scientific approach, the methods developed can be used by grid operators. As the power flow calculation and the sensitivity factors further develop and improve existing methods, they can be integrated into existing processes and their added value utilised.
Publications
-
Improved quasi-steady-state power flow calculation for district heating systems: A coupled Newton-Raphson approach. Applied Energy, 295, 116930.
Dancker, Jonte & Wolter, Martin
-
Sensitivity factors in electricity-heating integrated energy systems. Energy, 229, 120600.
Dancker, Jonte; Klabunde, Christian & Wolter, Martin
-
A coupled transient gas flow calculation with a simultaneous calorific-value-gradient improved hydrogen tracking. Applied Energy, 316, 118967.
Dancker, Jonte & Wolter, Martin
-
A Joined Quasi-Steady-State Power Flow Calculation for Integrated Energy Systems. IEEE Access, 10, 33586-33601.
Dancker, Jonte & Wolter, Martin
-
„Sensitivity Factors for Integrated Energy Systems: A Quasi-Steady-State Approach“, MAFO, Band 91, 2022,
Dancker, Jonte
-
Power-Transfer-Distribution-Factor-Based Sensitivity Factors for Integrated Energy Systems. IEEE Transactions on Sustainable Energy, 15(1), 486-498.
Dancker, Jonte & Wolter, Martin
