Economic Evaluation of Solution Alternatives for Voltage Sags and Momentary Interruptions

Tosak Thasananutariya 1, Somchai Chatratana 2, Mark McGranaghan 3, 1) Metropolitan Electricity Authority (MEA), Thailand 2) National Science and Technology Development Agency (NSTDA), Thailand 3) EPRI Solutions, United States

This paper proposes a practical method for economic evaluation of different alternatives to improve the performance of industrial facilities for voltage sags and momentary interruptions. Different technologies for solving voltage sag problems are discussed (both utility and customer solutions) and a procedure for evaluating the economics of the different alternatives is described. The concept of weighting factors to account for different levels of equipment sensitivity and customer costs as a function of the disturbance severity is introduced. This method allows for convenient evaluation of voltage sag impacts along with momentary interruption impacts. The economic analysis uses standard financial measures, such as the payback period, net present value (NPV), and internal rate of return (IRR) to assess the alternatives. The methodology is illustrated using a case study of voltage sag performance improvement alternatives at an industrial customer located in the Metropolitan Electricity Authority (MEA) service area.