An optimal load curtailment method for operational risk assessment of integrated electricity, natural gas and heating systems

Abstract

The rapid development of gas-fired generators and combined heat and power (CHP) units promotes the wide application of integrated electricity, natural gas and heating systems (IEGHSs). IEGHSs bring many opportunities to energy supply systems, but also produce huge challenges for ensuring secure and reliable energy supply. Therefore, it is indispensable to investigate the risk assessment for IEGHS operations, especially considering the complexity of system operations. First, a steady-state system model of IEGHSs is developed and linearized taking into account system operation characteristics, including generator operation constraints and the flexibility of CHP units. To reduce computation complexity, an optimal load curtailment method using a mixed integer linear programming algorithm is proposed, which considers both energy types and consumer importance of IEGHSs. Moreover, a contingency set based on the N-1 guideline is constructed taking into account the failures of IEGHSs with high probability. Additionally, the risk indices of IEGHSs are developed in two hierarchies: contingency level and system level. Furthermore, the operational risk of IEGHSs under the constructed contingency set is quantitatively evaluated using the proposed load curtailment method and the developed risk indices. Finally, case studies demonstrate the necessity of operational risk assessment and the effectiveness of the proposed method.