Partial Discharge Measurements

Partial Discharge Measurements: Earlier the testing of insulators and other equipment was based on the insulation resistance measurements, dissipation factor measurements and breakdown tests. It was observed that the dissipation factor (tan δ) was voltage…

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Schering Bridge Theory

Schering Bridge Theory for Three Terminal Measurement: For two terminal measurements the bridge is grounded at its junction points. The supply transformer, detector, and all the components of the bridge are enclosed in earthed shields.…

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Dielectric Constant and Loss

Dielectric Constant and Loss: Many insulating substances have dielectric constant greater than unity and have Dielectric Constant and Loss when subjected to a.c. voltages. These two quantities, namely, the dielectric constant and the loss depend…

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Insulation Coordination of Substation

Insulation Coordination of Substation: For steep fronted lightning waves at Insulation Coordination of Substation and at different points on lines, the voltages at sub-stations may exceed the protective level depending on the distances involved and…

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Selection of Surge Arresters

Selection of Surge Arresters: These are non-linear resistors in series with spark gaps which act as fast switches. A Selection of Surge Arresters or lightning arrester is shown in Fig. 8.24 and its characteristics are…

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