Operational Reliability Assessment of Integrated Heat and Electricity Systems Considering the Load Uncertainties

The wide deployment of combined heat and power (CHP) has intensified the interdependence between district heating network (DHN) and electric power system. Under such circumstances, the operational reliability assessment of the integrated heat and electricity system (IHES) becomes a significant issue, that has not been comprehensively studied before. In this paper, the reliability models of the coupling devices in the IHES, i.e., CHP units and heat pump (HP) units, are first developed considering two interdependent performance variables. Energy loads are represented by fuzzy multi-state models to capture the uncertainties due to the forecast, model, and data errors. The scenario-based combined heat and power dispatch (CHPD) model is proposed to calculate the nodal reliability indices. Several techniques are utilized to improve the computation efficiency of the reliability assessment technique. First, the traditional universal generating function (UGF) method is extended to the IHES context to combine the coupling device states and consequently reduce the number of scenarios that need to be considered. Second, a hydraulic-thermal decomposition technique is proposed to decompose the CHPD model into two linear programming (LP) models that can be iteratively solved. Case study illustrates the proposed reliability assessment framework and the effectiveness of the solution technique.