Validation tests for the application of a circular PMA with slotted ground plane for partial discharges detection in power transformers

In this article, the applicability of an UHF circular printed monopole antenna with slotted ground plane was evaluated in order to detect partial discharges in power transformers. To verify the applicability of the antenna, two measurement batteries were performed: reflection coefficient (bandwidth) and gain in an anechoic chamber, to avoid external interference; and PD sensitivity tests from the comparison with the conventional method of IEC 60270, using for this purpose an oil cell with immersed flat-tip electrodes. These analyzes were performed for the design of an antenna with optimized performance. The obtained values for the antenna's bandwidth, size, gain and PD detection sensitivity make it possible to classify the antenna as efficient in detecting partial discharges in power transformers.