PCB-Based Planar Inductive Loops for Partial Discharges Detection in Power Cables

Abstract

Partial discharge (PD) diagnosis tests, including detecting, locating, and identifying, are used to trace defects or faults and assess the degree of aging in order to monitor the insulation condition of medium- and high-voltage power cables. In this context, an experimental evaluation of three different printed circuit board (PCB)-based inductive sensor topologies, with spiral, non-spiral, and meander shapes, is performed. The aim is to assess their capabilities for PD detection along a transmission power cable. First, simulation and experimental characterization are carried out to determine the equivalent electrical circuit and the quality factor of the three sensors. PD activity was studied in the lab on a 10-m-long defective MVAC cable. The three PCB-based sensors were tested in three different positions: directly on the defective cable (P1), at a separation distance of 10 cm to 3 m (P2), and on the ground line (P3). For the three positions, all sensors’ outputs present a damped sine wave signal with similar frequencies and durations. Experimental results showed that the best sensitivity was given by the non-spiral inductor, with a peak voltage of around 500 mV in P1, 428 mV in P2, and 45 mV in P3, while the meander sensor had the lowest values, which were approximately 80 mV in P1. The frequency spectrum bandwidth of all sensors was between 10 MHz and 45 MHz. The high sensitivity of the non-spiral inductor could be associated with its interesting properties in terms of quality factor and SFR, which are due to its very low resistivity. To benchmark the performance of the designed three-loop sensors, a comparison with a commercial high-frequency current transformer (HFCT) is also made.

Radiometric Partial Discharge Detection: A Review

“…The RF approach utilizes appropriate sensors to detect and receive the electromagnetic wave generated when PD occurs. The emitted EM radiation consists of a combination of different frequency components up to a few GHz, which are classified into three bands: high-frequency (HF), very high-frequency (VHF), and ultra-high-frequency (UHF) [58]. RF-based techniques to detect PD activity have interesting characteristics because they allow noninvasive, continuous, and low-cost monitoring of PD activity.…”

“…Furthermore, laboratory experiments have been carried out on the loop spiral antenna, showing its suitability for the detection of the three types of PDs, namely, corona, internal, and surface [53]. (e) PCB-based non-spiral inductive sensor [58], and (f) single turn magnetic loop antenna [96].…”

“…During the experiment, the magnetic loop antenna (with a resonance frequency of around 32 MHz) was placed in two different positions in the GIS to detect three types of PD: corona, surface, and free-moving particles. When compared to the HFCT sensor, the results showed that the antenna could detect PDs in the HF/VHF [93], (c) antenna panel [95], (d) on-chip integrated spiral antenna [95], (e) PCB-based non-spiral inductive sensor [58], and (f) single turn magnetic loop antenna [96].…”

“…Figure11. Loop antennas designed for PD detecting by: (a) circular loop antenna[60], (b) multi-turn circular loop antenna[93], (c) antenna panel[95], (d) on-chip integrated spiral antenna[95], (e) PCB-based non-spiral inductive sensor[58], and (f) single turn magnetic loop antenna[96].…”