Partial Discharge Detection and Analysis Using Radiometric Method

Abstract

Partial discharge is common at defective sites within electrical insulation, such as de-laminations, cavities, joints, or voids in high-voltage generators, power transformers, power lines, and power cables. It is recognized as a major source of degradation in electrical equipment.

The significance of electrical insulation in power cables, transformers, and switchgear is underscored, as it is susceptible to degradation under various operational stresses. The reliability and durability of this equipment are crucial, leading utility companies to invest in increasing equipment reliability. Simultaneously, researchers in the field of diagnosis and insulation assessment are exploring new methods of PD measurements.

Consequently, extensive research has been conducted to detect and interpret PD for the purpose of diagnosing electrical power equipment.

Current methods for measuring partial discharge, such as the conventional method defined by IEC-60270, suffer from limitations such as poor signal-to-noise ratio (SNR) in noisy on-site conditions and the requirement of disconnecting the system under test. This thesis proposes the radiometric method as an alternative approach to PD diagnosis and measurement.

This thesis focuses on diagnosing and measuring partial discharge (PD) in electric power equipment, aiming to contribute to the field by introducing a non-conventional method known as the radiometric method.

The research methodology includes a simulation study to compute the electric field magnitude and its distribution for various test configurations. This study aims to identify sites of field augmentation in the test samples used in the experimental work, such as sharp edges of electrodes, cavities within solid dielectrics, and HV metal edges on dielectric surfaces, as partial breakdown commonly occurs at these locations. Experimental results of PD measurements using three different methods—IEC 60270, high-frequency current transformer (HFCT), and ultra-high frequency (UHF)—will be demonstrated.

Furthermore, the thesis incorporates finite difference time domain (FDTD) simulation work to compute the radiated electromagnetic fields from the partial discharge location and evaluate the response of the UHF measuring antenna by investigating various discharge parameters, such as magnitude, length, and frequency, to enhance the understanding of the antenna's response to different PD scenarios.

By employing the radiometric method and integrating simulation studies with experimental data, this thesis aims to enhance the understanding and measurement accuracy of partial discharge in electric power equipment. The findings will contribute to the development of more reliable and efficient PD diagnosis techniques, ultimately improving the overall reliability and durability of electrical insulation in power systems.

Date of Award	Aug 2023
Original language	American English
Supervisor	NOUREDDINE Harid (Supervisor)