Risk-constrained transmission network expansion planning in competitive electricity markets considering expected energy not supplied and wind curtailment

Abstract

The increasing use of wind resources has led to new challenges in transmission network expansion planning (TNEP). Wind curtailment due to improper expansion of transmission lines prevents the optimal use of these renewable resources. In addition, the uncertainty of these resources puts expansion decisions at risk. In this paper, risk-constrained TNEP in electricity markets in the presence of wind resources is presented with the aim of increasing the utilization of these resources by considering the wind curtailment cost and reducing expected energy not supplied (EENS). For this purpose, a risk-constrained bi-level stochastic model is used. At the upper level, transmission network expansion decisions are made by the independent system operator (ISO) with the aim of minimizing network investment cost and EENS cost. At the lower level, the market-clearing problems are solved maximizing social welfare. Using duality theory, the bi-level problem is converted into a mixed-integer linear programming (MILP) problem. The proposed framework is analyzed using Garver’s six-bus test system and the IEEE 24-bus reliability test system (RTS). The simulation results indicate that considering wind curtailment cost has increased the use of wind units and reduced the expected energy produced by fossil units, which is important from an environmental point of view. However, considering the risk, due to the uncertainty of wind resources, the energy produced by these resources has decreased.

Keywords

• expected energy not supplied
• transmission network expansion planning
• risk
• wind power curtailment