Bayes inference for reliability of uv insulation systems in the presence of switching voltage surges using a weibull stress-strength model

Abstract

This paper shows a Bayesian approach to evaluate the effect of switching overvoltages on HV insulation reliability. Indeed, HV insulation is often designed to withstand rated temperature and nominal (AC or DC) voltage but not voltage surges, whose amplitude can largely exceed rated voltage even in the case of switching overvoltages. Since both voltage surges and insulation electric strength (affected by aging) have stochastic nature, reliability evaluation involves the use of the relevant probability distributions, whose parameters a r e generally known with large uncertainty. Thus, the methodology for reliability assessment here presented, based on Bayesian estimation, is a useful tool in the case of HV insulation subjected to switching voltage surges. Under proper assumptions, among which a particular Weibull stress-strength model -leading to a Loglogistic distribution for lifetime -the proposed method enables the analytical determination of prior and posterior distributions of reliability and other related parameters, such as given percentiles of service life, and their Bayes point and interval estimates. The analytical feasibility and simplicity of the procedure a r e illustrated in the paper by means of a numerical application, and the efficiency of estimates is shown through extensive Monte Carlo simulations. The method is applied to HVAC cable insulation.

Dynamic reliability evaluation for a multi-state component under stress-strength model

“…For more details, see Chiodo et al [4], Chiodo and Mazzanti [5] and Eryılmaz [10]. Clearly, using (3.4) and (3.5) for t = 0.1, 0.2, · · · , 2 and selected values of the parameters θ 1 and θ 2 , we can obtain D (t) KL(l) and R l (t) values presented in Table 1.…”

Maximum lightning overvoltage location and reliability indices in power system with combined transmission line

“…Therefore, many efforts have been done for increasing high voltage reliability insulation, e.g. improving insulation endurance and optimizing insulation system design [5].…”

“…Therefore, many efforts have been done for increasing high voltage reliability insulation, e.g. improving insulation endurance and optimizing insulation system design [5].Reliability analysis of the power system that contains combined line is very important because most faults on transmission lines are transient and these faults do not cause that overhead line be permanently out of service. Transient faults are typically caused by lightning activity, and they have a very short duration.…”

Indirect reliability estimation for electric devices via a dynamic "Stress-strength" model

“…In the field of assessment or estimation of power system component reliability, the usefulness of suitable "Stress-Strength" (SS) models [1,2] has already been stated and illustrated by the Authors [3][4][5][6][7], using typical lifetime data of Electrical insulation. In particular, in the present paper a SS model is developed in which the stress causing aging and/or failure of the device is modeled as a succession of "shocks" (e.g.…”

“…In particular, the paper is focused upon statistical methods for the "indirect estimation" of the reliability function or related parameters, which appears to be the most rationale way for taking into account the "apriori" engineer's knowledge, as also shown by the Authors in previous or papers [3][4][5]. The model here presented is somewhat more general than that described in a related paper presented by the Authors at this same Conference [6], in which a single shock is considered.…”