Tham khảo tài liệu 'electrical generation and distribution systems and power quality disturbances part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Reliability Centered Maintenance Optimization of Electric Distribution Systems 87 their strategies. Thus the random or deterministic strategy of preventive renewals is added to a random process of failure renewals. The classification of renewal actions can be performed on several criteria of which we remind a few the purpose timing and costs of their occurrence distribution and frequency and last but not least the effects on the system safety Anders et al. 2007 . In this work we analyze and study only preventive renewal processes through their modelling influence on the system in the following cases - the system is known due to the reliability function and reliability indices based on data received from operation - PR actions have the purpose of reducing the influence of the system wear and thus improve its reliability which are considered preventive maintenance actions PM from this point of view - PR does not entirely change the characteristics of the system and after the renewal action the evolution of the system follows the same law of reliability until a new renewal - determining the PR frequency on the system will be based on technical criteria and or economic ones - PR of system elements will be performed considering the same assumptions of study as the system as a whole. The evolution of an equipment will thus be represented by the succession of renewal moments t1 t2 . tn and the intervals between them x1 x2 . xn . presented in the Figure 2. IX1 . x2 . . . xn I---- -----K----------X-------- -X-----------X----------X------- T h t2 tk . . . til-1 tn Fig. 2. The evolution of an equipment with renewal If it is considered a certain time interval 0 t the number of PR denoted by Nt performed during this time is a discrete deterministic process called preventive renewal process as the basic component of preventive maintenance which in turn determine planning development and the effects of RCM on system. This requires the development of PR strategies enabling .
