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Preventive electrical maintenance and fault management

Archive for the ‘Industrial Thermography’ Category

A paper on Improving results of thermographic inspections of electrical transmission and distribution lines on IEEE by Snell, J.; Renowden, J.

Transmission and Distribution Construction, Operation and Live-Line Maintenance Proceedings. 2000 IEEE ESMO – 2000 IEEE 9th International Conference on
Volume , Issue , 2000 Page(s):135 – 144
Digital Object Identifier   10.1109/TDCLLM.2000.882811

Summary:Inspecting compression splices on transmission and distribution lines has long been accomplished using infrared thermography but the results have too often been disappointing. There are instances of splices failing within months of infrared inspections. An understanding of the actual condition of the splices had been “masked” by one or more of the factors discussed in this paper. A number of factors are involved, including a poor understanding of the application of the technology; inadequate training of some service providers; environmental factors; low electrical loading; the resolution limitations of the inspection equipment; low emissivity of the components, and poor interpretation of the data. Too often the severity of the problems found has been underestimated and some bad fittings have simply not been located. In a deregulated environment, electric utilities will require more predictable reliability. In part, this will be accomplished through a much higher level of confidence in the assessment of the condition of compression fittings. This paper discusses the background for using thermography in the industry and the results that have been achieved in the past, as well as the use of resistance measurements to assess the condition of compression fittings. It also details steps that can be taken to improve the infrared results to provide for greater confidence in the interpretation of the data collected

Benefits of Infrared Electrical Inspections

Electricty-Today has an interesting article on the benefits of Infrared Electrical Inspections:

Since most problems on an electrical system are proceeded by a change in its thermal characteristics and temperature, whether hotter or cooler, a properly trained and experienced thermographer is able to identify and analyze these problems prior to costly failure occurring.

Infrared electrical inspections provide many benefits to the recipient. The two key advantages from which the others stem, are:

  1. The reduction in disassembling, rebuilding or repairing components which are in good operating condition. This type of repair is meaningless and costly and may lead to a 30 percent reduction of production. Furthermore, it is not guaranteed that the component will be in better condition after the repair, since the location of the problem or cause was not established. With infrared thermography you identify and hence repair only what needs repairing.
  • Problems that truly exist will be identified quickly, giving time to repair the problem before failure. In most cases, the problem is identified well before the problem becomes critical. Depending on the temperature and criticality of the component, the decision can be made to repair immediately, repair at the first opportune time, or monitor on a continual basis until the critical temperature is reached or until the repair can be scheduled. Identifying a true anomaly, scheduling the repair, and eliminating the actual cause of the problem within a proper time frame is the most efficient and cost effective way to maintain the system.
  • Electric Media can provide thermography services for your organization. Please contact us.

    Electrical Thermography

    The main application for thermography has always been, and still is, electrical system inspections. Infrared thermography has been used as a condition monitoring tool to predictively maintain electrical systems, even before the terms “condition monitoring” and “predictive maintenance” were used. In 1965, the Swedish Power Board began inspecting approximately 150,000 components a year. In 1976, the UK Electrical Generation Board began utilizing infrared thermography for predictive maintenance on transmission lines. Ontario Hydro and BC Hydro in Canada also became involved in infrared thermography during this time.

    By the year 2000, virtually every electric generation and distribution company, as well as every major manufacturing and process facility, will be using infrared thermography as a condition monitoring technique to increase reliability and decrease downtime.

    Why such an interest in electrical thermography? Simple. All electrical maintenance personnel know that as soon as new electrical components are installed they begin to deteriorate. With fluctuating and continual loads, vibration, fatigue, age, and other things like operating environment, all of these will increase the probability of faults in electrical components. These faults, if not found and taken care of, will lead to catastrophic failures, unplanned shutdowns and losses of production.

    Benefits of Infrared Electrical Inspections

    Since most problems on an electrical system are proceeded by a change in its thermal characteristics and temperature, whether hotter or cooler, a properly trained and experienced thermographer is able to identify and analyze these problems prior to costly failure occurring.

    Infrared electrical inspections provide many benefits to the recipient. The two key advantages from which the others stem, are:

    1. The reduction in disassembling, rebuilding or repairing components which are in good operating condition.

    This type of repair is meaningless and costly and may lead to a 30 percent reduction of production. Furthermore, it is not guaranteed that the component will be in better condition after the repair, since the location of the problem or cause was not established. With infrared thermography you identify and hence repair only what needs repairing.

    2. Problems that truly exist will be identified quickly, giving time to repair the problem before failure.

    In most cases, the problem is identified well before the problem becomes critical. Depending on the temperature and criticality of the component, the decision can be made to repair immediately, repair at the first opportune time, or monitor on a continual basis until the critical temperature is reached or until the repair can be scheduled. Identifying a true anomaly, scheduling the repair, and eliminating the actual cause of the problem within a proper time frame is the most efficient and cost effective way to maintain the system.

    Other Advantages of Infrared Electrical Inspections

    The other advantages of an infrared inspection program are based on the above overall advantages, yet are no less important. They are:

    • Safety – failure of electrical components could be catastrophic, injuring or even killing employees, maintenance personnel or the public.
    • Greater system security – locating the problems prior to failure greatly reduces unscheduled outages, associated equipment damage and downtime.
    • Increased revenue – with more uptime, revenue is maximized. With less maintenance on good components and faster repairs of faulty components, maintenance costs are reduced leading, to a better bottom line.
    • Reduced outage costs – the cost of an emergency outage is ten times greater than planned maintenance.
    • More efficient inspections – since all common electrical problems announce themselves as an increase in temperature, they are easily detected in a minimum amount of time. No service interruption is required for infrared inspections.
    • Improved and less expensive maintenance -
      • precise pinpointing of problems minimizes time required for predictive and preventive maintenance,
      • maintenance efforts are directed to corrective measures rather than looking for the problem,
      • repair only what requires repairing, reducing repair time and unnecessary replacement of good components.
    • Reduce spare parts inventory – with improved inspection techniques giving advanced warning of failure, fewer spare parts are required in inventory. What would it mean to the bottom line if your spare parts inventory could be reduced by 10 per cent?
    • Reduced operational costs – with the system up and running for longer periods of time, the reduction and improvement of inspections, maintenance, spare parts inventory and outages will reduce the overall cost of operations.

    (Quoted from article in Electricity Today)