System dependant IDMT settings: direct buried underground cable

Nagel, Gregory (2014) System dependant IDMT settings: direct buried underground cable. [USQ Project]


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As modern day power protection devices become smarter, more configurable and more accurate, they offer users the ability to configure the exact protection elements and settings required for a specific network section. This combined with the increased number of power systems going underground provides the basis for this research project. As we look to optimise our power networks and the protection of our power networks, we must ask, how can we ensure that our protection relays have the optimal settings for our underground network?
Presently, when determining the time-dependant over-current protection settings for underground cables, all worst-case scenarios are considered, resulting in excessive safety margins and over-protective configurations. Whilst these excessive safety assumptions ensure adequate protection for the electrical asset, they also potentially work to increase the possibility of false fault detection. Such an error leads to unnecessary supply isolation and consequently, costly downtime.
Given these limitations to current methods for determining protection settings, this research project develops and implements a simulation model using finite element analysis that analyses specific underground cable systems based on operating and environmental conditions. By determining the steady-state thermal profile of the underground cable system as a result of the load current, the simulation continues to analyse the effect of fault current on the system to determine the most suitable protection settings for the underground cable system.
The results presented herein outline the effect that environmental conditions have on the required protection settings of underground cable systems, and when used in conjunction with the simulation software, provide valuable information to assist design engineers making decisions on a system's setting values for numerical protection relays.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering - Electrical and Electronics project.
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Ahfock, Tony
Date Deposited: 16 Sep 2015 02:25
Last Modified: 11 Feb 2016 03:37
Uncontrolled Keywords: underground cable, IDMT over-current protection, finite element analysis (FEA)
Fields of Research (2008): 09 Engineering > 0906 Electrical and Electronic Engineering > 090699 Electrical and Electronic Engineering not elsewhere classified
Fields of Research (2020): 40 ENGINEERING > 4008 Electrical engineering > 400899 Electrical engineering not elsewhere classified

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