| Popis: |
In this chapter an overview is given of the more important methods employed in the supply industry for assessing the condition of insulation in power system equipment before leaving the factory, on commissioning, during service and when under going major maintenance or repair. The particular requirements for equipment of different insulation structures are described in Chapter 7, including reference to Standards where appropriate. More advanced recently developed methods are presented in Chapters 8-10. The earliest methods for determining whether or not an insulating material was suitable for a particular usage included the application of steady-state voltages for, perhaps, one minute at twice or more the operating stress. Later, this was followed by the development of surge voltage tests to simulate lightning and system switching effects. Much research was necessary in the design and construction of high voltage test equipment and associated test/laboratory areas. |
