Explaining The Need For Monitoring Transformer Bushings

Posted by adairsawyer on August 28th, 2011

For most people unfamiliar with the workings of high voltage electrical components, the word ‘bushing’ would not be a familiar one. This is not surprising as bushings are highly specialized electrical components found alongside electrical transformers. A bushing is essentially an insulated enclosure through which a conductor passes, with the conductor being connected at either end to different pieces of equipment. Thus the bushing usually protects a conductor connected at one end to a transformer and at the other end to whatever equipment that requires the electricity passing through the transformer. The problem is that bushings are not foolproof, and are prone to failure, making it essential that bushings be monitored. Previously, many operations made use of periodic monitoring but it is now generally accepted that continuous bushing monitoring is the better method of monitoring transformer bushings.

As a starting point, monitoring transformer bushings is important because bushings are constantly being put under high stress by the sheer amounts of high voltage electricity flowing through the transformers they are attached to and also from environmental stresses such as heating by the sun’s rays. All of these stresses can cause the insulation on the bushing to deteriorate, and if a crack or flaw should appear in that insulation, the bushing might fail. Monitoring transformer bushings is therefore extremely important, because bushing failure on a transformer can lead to a great deal of damage to the transformer and other nearby equipment and can also endanger the lives of those working in close proximity to the transformer.

One possible result of a bushing failure is that the transformer catches fire and explodes, which can then result in equipment damage, injuries and even loss of life for those workers in the vicinity. Of course, not all bushing failures leads to fires and explosions, but the risk of that end result makes it necessary for operations to do their utmost to ensure that they are protected against such occurrences. Monitoring transformer bushings is therefore the only way to better guard against bushing failure.

Previously, operations made use of a method known as periodic monitoring to keep a watch on transformer bushings. This involved taking a transformer offline on a regular basis, and closely inspecting the bushings for cracks or imperfections that might lead to a bushing failure. Due to the fact that the transformers have to be taken offline, however, this is most certainly not a popular method with most operations, and managers have a tendency to keep the checks to a minimum. The problem with this method of monitoring is that problems can easily develop in between checks, and bushings are certainly capable of failing in the time between checks.

Continuous bushing monitoring is a relatively recent phenomenon, and only came about with the development of equipment that could be used to remotely monitor the condition of transformer bushings. With continuous bushing monitoring, sensors are affixed to the transformer bushings that measure certain indicators such as temperature or electrical current. A change in the measurements of these indicators signifies that a minor failure has taken place and that a major failure is probably close behind. This will give operators the opportunity to find and fix the problem area before a major failure can take place. With continuous bushing monitoring, the rate of bushing failure is sure to fall and this will provide for a lower likelihood of interruption of power – something which all the companies that depend on a particular power supply are sure to be very concerned about.

With the advent of continuous bushing monitoring, made possible by equipment available from Dynamic Ratings, monitoring transformer bushings has never been simpler, and ensuring an even and uninterrupted supply of power has become even less of a hassle for electricity operators.

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