Sub-Station Reliability

A new reliability index, specific for Indian context, labeled average load concentration/spread index (ALC/SI), which forms the basis for bus configuration selection, is proposed in the fifth chapter. This new index is proposed to choose the right bus configuration of a sub-station to limit frequency and duration of the interruptions and also reduce impact of interruptions on grid stability.

Component Reliability

Causes of failures, case studies from power utility, and suggestions for the reduction of failures of components are presented in the third chapter. Component-wise effect on overall systems based on failure criticality index is also computed for two sample systems based on Birnbaum's measure. Lack of performance by power system components will reduce the reliability of the overall system affecting either the system adequacy or the system security or sometimes both.

Reliability Concepts

The first chapter introduces basic concepts of Reliability and their relationships. Four probability functions—reliability function, cumulative distribution function, probability density function, and hazard rate function—that completely characterize the failure process are defined. Three failure rates—MTBF, MTTF, MTTR—that play important role in reliability engineering design process are explained here. The three patterns of failures, DFR, CFR, and IFR, are discussed with reference to the bathtub curve. Two probability models, Exponential and Weibull, are presented. Series and parallel systems and application areas of reliability are also presented.

Transmission Line Reliability

The fourth chapter deals with transmission line reliability evaluation. For carrying out reliability studies, regression and Markov methods are applied to the field data. Regression approach is applied to predict the future performance based on the past data obtained from the field. Markov method is used to compute the reliability indices such as availability, unavailability, failure rate, repair rate for performance evaluation of the power transmission system. Transmission line performance assessment depends on data collection capabilities and performance metrics to ensure continued grid adequacy and security.

System Reliability

Power system adequacy and security with reference to probabilistic and deterministic approaches are dealt in the second chapter. Increased investment leads to improved power availability and underinvestment leads to reduction in quality of power supply. The related optimal reliability with respect to cost is explained here. Extensive computerization of data is required for assessing the benefit of expansion and reinforcement/augmentation schemes for obtaining improved availability in the context of deregulated utility environment.

ANN-Based Short-Term Load Forecasting

Load forecasting is a very crucial issue for the operational planning of electrical power systems. In the sixth chapter, it is formulated that a reliable power network along with load prediction models is essential for uninterrupted supply of electrical energy to the consumers. The Back-Propagation ANN algorithm is applied to forecast the load of the power system. Based on the load forecasted power components, transmission lines and sub-stations are augmented for improved reliability in a province.