Power-Transfer-Distribution-Factor-Based Sensitivity Factors for Integrated Energy Systems

Abstract

The stronger the electric power, district heating and gas system are linked in an integrated energy system (IES) the larger their flexibility potential but also their complexity. To ensure a secure system operation, the effect of a coupling unit's power change on the overall system state must be analyzed before the power change is carried out. Otherwise, coupling units can unintentionally cause limit violations in one energy system. Currently, for such analyses a power flow calculation must be performed, which is computational expensive and timeconsuming. This paper presents sensitivity factors extending Power Transfer Distribution Factors from electric power system analysis to IES. The sensitivity factors include the dynamic behavior of district heating and gas systems as we derive the sensitivity factors from a joined quasi-steady-state power flow calculation. In two case studies we profoundly test the applicability of the IES sensitivity factors, their accuracy, and limitations. We show that the sensitivity factors are on average ten times faster in estimating a new system state after a unit's power change compared to a power flow calculation. Also, the sensitivity factors can provide good estimates and have a higher accuracy than sensitivity factors which are derived from a steadystate power flow calculation.

Vulnerable Area Identification of Islanded Combined Electrical and Heat Networks Based on Static Sensitivity Analysis

“…Most of the current studies of sensitivity analysis for IESs focus on system optimization. However, there have been some studies using sensitivity for system state estimation of IESs: [27] introduced the Power Transfer Distribution Factors from power system analysis into IES, which greatly speeds up the estimation of the overall state of the system after a power change in a coupled unit compared to power flow calculations. In [28], a static sensitivity analysis of power system voltages was performed, and the weak buses of power systems could be quickly identified.…”