Methodology for assessment of financial losses due to voltage sags and short interruptions

This paper proposes a comprehensive methodology to estimate the financial losses incurred by voltage sags and short interruptions to industrial plants. The proposed methodology uses various techniques to tackle different levels of failure risk assessment. Failure risks of sensitive industrial equipments, sub- processes and processes are assessed in sequence before the failure risk and financial losses of an industrial plant are estimated. The most important part of the methodology involves failure risk assessment of sensitive equipments, where a fuzzy logic based model is built to address the inherent uncertainties in equipment behavior when subjected to voltage sags and short interruptions. Failure risk assessment at sub-process level considers the composition ratio and importance level of each equipment type in the sub-process. Finally, failure risk assessment of processes and the entire plant adopts the technique of fault tree analysis. By considering more risk affecting factors, the proposed methodology promises improved accuracy and practicability.