PD Monitoring on Transformers
Partial discharge monitoring has become increasingly important in the past few years. Besides other parameters like gas in oil analysis, temperatures, vibrations, or load conditions, etc., the PD trending information completes a full set of monitoring data of a transformer in the field. A series of standard bushing adapter (BA) is available to connect the measurement system to the test tap of condenser bushings. Even special designs are available on request. Additionally, the standard setup using the bushing test tap could be extended with UHF drain valve sensors or embedded antennas in flanges. For continuous monitoring, an instrument such as the ICMmonitor can be considered. Acoustic sensors can be used to locate a PD fault more precisely.
Beside of the preferred HF PD decoupling from the capacitive test taps of the transformer bushings (BA & BCU2C), it can be an option to take the UHF signal in addition or instead. Suitable UHF PD sensors are available from Power Diagnostix for the oil drain valve (TVS2) or for flanges of inspection holes (TFS1). The advantage of less influence of external noise signals stands in contrast to the lower detection sensitivity of PD activity generated from failures from within the winding. However, a combination of both techniques can be considered as a good compromise.