Modeling and experimental verification of on-line PD detection in MV covered-conductor overhead networks

Abstract

The falling trees on covered-conductor (CC) overhead distribution lines produce partial discharges (PDs). The measurements have been taken in the laboratory and PD signal characteristics under various circumstances have been described. In this paper, an on-line single-phase PD monitoring system using Rogowski coil is simulated in EMTP-ATP. The simulation results are compared with those obtained from the laboratory measurements. The proposed model can be used to estimate the length of the practical CC lines at which PDs due to falling trees can be detected and localized; thus, deciding the number and positioning of the sensors over a particular length of the CC lines. The different noise sources have been described that cause interference with low level PD signals, which is a major challenge for on-line/on-site condition monitoring. The design aspects of the wireless sensor for this specific application are also discussed. Automatic detection of falling trees will reduce visual inspection work after storms and it will improve reliability and safety of the CC distribution system.

A Pattern Recognition Method for Partial Discharge Detection on Insulated Overhead Conductors

“…This can become a potential reliability threat in some locations where the tree and tree branches frequently hit the conductors due to wind or continuously push and bend the conductors. Eventually, the power line will be damaged, causing a power outage or starting a tree fire [2][3].…”

Electromagnetic sensing for predictive diagnostics of electrical insulation defects in MV power lines

“…The lines are spread miles long, supplying electrical power to consumers. The major cause of PD in CC lines is the leaning trees due to storms, load of snow or natural bending during growth [4]. Similarly, in order to maintain the aesthetics and safety of the environment, installation of underground cables has been on rapid increase especially in the cities during recent years.…”

“…Predictable failures normally have certain traces by which ongoing failure mechanism can be detected with the help suitable monitoring system. Insulation degradation is one the most common causes of failures in critical power components, transformers, switchgears and power lines (cables and over-head covered conductors) [3,4].…”

Wavelet-based de-noising of on-line PD signals captured by Pearson coil in covered-conductor overhead distribution networks

“…It is matter of fact that PD measurements conducted in the HV laboratory Faraday cage are normally free from interferences, however, simulation results had shown that the measurements taken in the laboratory environment may include disturbances when PD signals may reflect from the CC line termination [18]. Therefore, PD signals captured by the Pearson coil in the laboratory environment should be de-noised using MSD technique.…”