Strategies for Electrical Network Expansion

Abstract

The main focus of the transmission expansion planning is to find the optimal structure and least cost transmission investment alternatives of the forecasted load and generation configuration. In this paper, transmission investment methodology which focuses on alleviation of transmission line congestions is proposed. The proposed methodology is based on DC power flow under constrained Lagrangian multiplier and the locational marginal price. Within this framework constraints and variables associated with the derivation of Lagrangian multiplier and the locational marginal prices are included in the formulated transmission expansion planning problem. This expansion problem which optimize the total investment and operation cost is modeled using a single-stage and multi-stage decision framework. In the single-stage transmission expansion planning framework a single load/ generation configuration is considered and the location, type and number of extra transmission lines of the optimal network configuration are determined. In the multi-stage model, multiple dispatch in the demand and wind power generation is integrated using a number of scenarios and the optimal expansion plan which fulfills the operating condition of all scenarios is determined through a three phase selection mechanism. For illustration purpose the resulting mixed-integer nonlinear programming problem is applied on the New England 39 bus test power system. Both proposed models are implemented in AIMMS software and solved using the outer approximation algorithm provided with the optimization tool.