机械制造厂总降变电所设计外文翻译(编辑修改稿)

机械制造厂总降变电所设计外文翻译(编辑修改稿)内容摘要：

urrence of failures represent safety or environmental hazards. All of this has led to an increase in the cost of maintenance. In some industries, maintenance costs represent the second highest or even the highest ponent of operating costs. STRATEGIES In general, maintenance is either planned or unplanned as shown in Figure 1. Corrective maintenance is a reactive strategy which is unplanned and is carried out after failure has occurred. The intention is to restore an item to a state that can perform its required function. Planned maintenance strategies are proactive in nature and can be divided into two groups: Preventive and Condition Monitoring. Preventive maintenance which is sometimes called scheduled, is a maintenance carried out at regular intervals. There are four basic tasks that can be selected under this category: Time Directed task involves number of operations, operating hours, or seasonal change. Failure Finding is for identifying equipment failure that are not evident to the operating crew (hidden failures). Usually used for protective equipment. Condition Directed applies to the situation when the condition of equipment reaches a limit, or when continued satisfactory operation can not be ensured. It prevents incipient failure from being real failure. Run To Failure is an option that is selected only in the event that a technically correct and costeffective task can not be identified. Predictive Maintenance (PdM) is carried out when it is deemed necessary, based on periodic inspections, diagnostic tests or other means of condition monitoring. Condition Monitoring is the monitoring or diagnostic activity that is used to predict equipment failure. 10 CENTERED MAINTENANCE (RCM) During the late 1960’s, the aircraft industry was on the verge of manufacturing the first “jumbo jets”. The new 747’s were three times the size ofany other passenger jets currently in the air. The recognized size of the 747, its new engines, and its many technology advances in structures, avionics, and the like, all led to Federal Aviation Administration (FAA) to initially take the position that preventive maintenance on the 747 would be very extensive – so extensive, in fact, that the airlines could not likely operate this airplane in a profitable fashion. This problem led the aircraft industry to pletely reevaluate its PM program. What resulted from this effort was a whole new approach that employed a decisiontree process for ranking PM tasks that were necessary to preserve critical aircraft functions during flight [3]. This new technique was eventually approved by the FAA and soon thereafter evolved into what is known as Reliability Centered Maintenance (RCM). RCM used by the airline industry led to major reduction in labor, material cost and inventory cost. Further it applied to nuclear power industry in the 1980’s. Today, RCM is the maintenance technique of choice for many industries including power industries. Unlike the airline industry which had the advantage of being able to work with manufacturers to create an RCM program for a new generation of equipment, the utility industry, especially the electric power generation industry, has had to adopt RCM as a modification of longestablished maintenance practices at existing plants [4]. Despite the costs associated with the implementation of these RCM programs in “midstream”, they have been found to pay for themselves in very short order. RCM, as has been mainly applied to nuclear power plants, often requires the largest amount of maintenance because of safety and environmental considerations. However, with these successful programs now operating, fossil power plants and power transmission and distribution systems have recently been getting into the mix. Because these facilities face a less restrictive regulatory environment, they should be able to directly apply the streamlines forms of RCM much more easily, thus reducing the implementation costs. The first step in revamping a maintenance program is to implement an RCM approach whichwill help establish priorities for a new program. Specifically, RCM is a set of methods and tools aimed at helping a utility to determine the minimum set of preventive maintenance tasks necessary to appropriately address critical equipment failures without promising service reliability. RCM is a structured process used to determine optimal maintenance requirements for equipment in a particular operating environment. It bines the strategies of corrective maintenance, preventive maintenance and predictive maintenance, and applies these strategies where each is appropriate, based。