Bushing Monitoring to protect Power Transformers against Bushing Failures

High voltage condenser bushings of power transformers, according to their construction and age, are amongst the most endangered components from all operating equipment used. In the past, off-line measurements like the measurement of bushing insulator capacitances and measurement of the dissipation factor were carried out for determining the operational state. Today, modern microprocessor and computer technology makes it possible to carry out the measurements and analysis continuous within a monitoring concept. The monitoring of the electrical measurement quantities is achieved by a voltage measurement consisting of a bushing adaptor, directly connected to the measurement tap of the bushing and connected voltage sensor. The output signal of one phase is compared with two remaining phases.…