This greatly reduces the chance that a problem will be missed because it occurs between discrete testing intervals. And it maximizes the chance that a failure with a short gestation time will be detected and prevented. In contrast to traditional testing, modern techniques provide detailed information on the relative changes of key parameters over time, without the need for highly accurate, absolute measurement of those parameters. If a parameter changes during the onset of fault conditions, a comparison to previous measurements will immediately detect it and, if necessary, sound the alarm. New on-line systems can therefore alert the asset manager of impending failure at the earliest possible instant.
New methods are also more flexible than traditional approaches.
For example, statistical evidence suggests that the tap-changing mechanism is the most likely part to fail. Traditional monitoring systems do little tap-changer monitoring, unlike modern techniques that can focus on the problem area. Furthermore, if a particular transformer has a history of problems, modern monitoring systems can be reallocated or reconfigured with relative ease. Through a highly developed form of analysis, the ability of DGA to prevent transformer failure depends on when and how frequently the test is performed and how long it takes for a given problem to cause a failure. As an alternative, ElectraNet SA uses on-line dissolved gas level sensors.