Download the full-sized PDF of Distribution System Condition Monitoring Using Active DisturbancesDownload the full-sized PDF



Permanent link (DOI):


Export to: EndNote  |  Zotero  |  Mendeley


This file is in the following communities:

Graduate Studies and Research, Faculty of


This file is in the following collections:

Theses and Dissertations

Distribution System Condition Monitoring Using Active Disturbances Open Access


Other title
Condition Monitoring
Distribution System
Active Disturbances
Type of item
Degree grantor
University of Alberta
Author or creator
Long, Xun
Supervisor and department
Xu, Wilsun (Electrical and Computer Engineering)
Li, Yun Wei (Electrical and Computer Engineering)
Examining committee member and department
Zhao, Qing (Electrical and Computer Engineering)
Salmon, John (Electrical and Computer Engineering)
Chang, Liuchen (Electrical and Computer Engineering, University of New Brunswick)
Li, Yun Wei (Electrical and Computer Engineering)
Xu, Wilsun (Electrical and Computer Engineering)
Department of Electrical and Computer Engineering
Power Engineering and Power Electronics
Date accepted
Graduation date
Doctor of Philosophy
Degree level
Utility companies have benefited from the use of condition monitoring to optimize the performance of their assets and enhance power system reliability. This thesis starts with a review of different applications of condition monitoring in a distribution system, and one of the findings is that several challenges faced by condition monitoring cannot be fulfilled by passive methods or offline monitoring. It is also found that power electronics has been utilized as an effective manner to create active disturbance in a distribution system. Based on these findings, power electronics aided online monitoring methods are presented to address three challenging condition monitoring problems. Proper grounding at a substation is a necessary practice for utilities to ensure substation safety and prevent equipment damage. This thesis presents an active online method which can continuously monitor the condition of a grounding grid. The current is created by a thyristor-based signal generator and injected into the tested grounding grid. The measured touch voltage and step voltage are then evaluated to determine if hazardous spots are detected. Fault detection in a de-energized feeder is another challenge for utilities, as all conventional passive detection methods cannot function in a de-energized system. This thesis describes an active method by using a three-phase thyristor bridge to inject signals into de-energized downstream. The corresponding voltage and current are analyzed to determine if a fault still exists. A harmonic impedance based algorithm is also developed to detect a symmetrical fault, and distinguish a fault from a shunt capacitor or a stalled motor, which behaves like a fault when a voltage is applied. Neutral-to-earth voltage has become an increased concern, as it not only has impact on livestock production, but also affects public safety. An active method to monitor neutral grounding integrity is presented. A small disturbance is injected into neutral by firing thyristors, and the neutral current flow is monitored to determine the neutral condition. The method can also be used to analyze the contributions of utility and customer to neutral-to-earth voltage.
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication

File Details

Date Uploaded
Date Modified
Audit Status
Audits have not yet been run on this file.
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 3037372
Last modified: 2015:10:12 14:36:40-06:00
Filename: Long_Xun_Spring 2013.pdf
Original checksum: 249e40e0ca31e23817dcb78830cbc96a
Well formed: true
Valid: true
File title: Introduction
Page count: 185
Activity of users you follow
User Activity Date