Bulk system reliability-predictive indices

Abstract

This paper is the second stage of an activity sponsored by the IEEE Application of Probability Methods Subcamittee centred on identifying techniques and approaches for monitoring, measuring, predicting and applying reliability indices in the planning and operation of power systems. The present paper identifies predictive indices that can be calculated, the degree to which they are calculated and used in practice, the comnonality or lack of it between utilities, the perceived problwith their calculation or practical use, the limitations due to lack of data, compter resources and mnagement understanding, and other related aspects. ImmIoN The function of a power system is to supply electrical energy on demand, economically and within acceptable levels of reliability and service quality. However, many other constraints and pressures on utilities exist. These include the need to provide return on capital as well as respond to political decisions and social obligations. A continuously available supply cannot be guaranteed for several diverse reasons such as random system failuresand delays in obtaining approval for generation sites and rights-of-way not always within the control of power syatem engineers. The probability of customer interruptions or lack of service quality (voltage, frequency, etc) at customer installations can be red& by increased investment during either the planning phase, operating phase or both. historically been based on deterministic criteria, design methods and operating procedures, although the nature of the problem and hence its solution, is probabilistically baaed. It is now not necessary to artifically constrain the inherent probabilistic nature of the problem into a deterministic one since a wide range of reliability techniques based on probability theory are now available 11-10]. This is not to suggest that all rodelling and evaluation problenm are solved since many The required level of investment has