Implications of Distributed Generation for Power Utility Protection Schemes when faults can be back fed! Will the topology have to change?

Implications of Distributed Generation for Power Utility Protection Schemes when faults can be back fed! Will the topology have to change?

Implications of Distributed Generation for Power Utility Protection Schemes when faults can be back fed! Will the topology have to change? (247)

Darren Woodhouse ¹ , Terry Summers ²

Safearth Consulting, Warners Bay, NSW, Australia
University of Newcastle, Newcastle, NSW, Australia

Power utility distribution circuits are protected by several layers of coordinated monitoring services, including relays, CTs, VTs and circuit breakers. Much is this technology is long proven and well established as reliable and cost effective. The introduction is large quantities of distributed generation will eventually lead to self sustaining circuits which will not de-energise when the utility supply is cleared. It has been assumed that the removal of the power utility supply will at worst lead to isolated pockets of LV. However there exists at least one scenario where faults on the distribution voltage, typically 11kV in Australia, will be supplied via the distribution transformers.

This paper looks at the conditions which will allow these faults to be created and whether the existing distribution topology will be able to handle them or will alternate protection measures be required? While these conditions are presently considered esoteric, the continued increase in distributed generation levels will eventually produce circumstances conducive to producing these faults. Between then and now we need to start considering solutions to these possibilities including significant changes to the accepted distribution network topology.

Authors contributing to this abstract.

Woodhouse, D

Darren Woodhouse is a Principal Engineer with Safearth Consulting. He has expertise in all areas related to earthing/grounding, including design, audit and test in sectors including power generation and delivery, heavy industry, mining, defense and rail. He received his BE(Elec.)(Hons I) (1993), BMaths (1994) and PhD (2004) from the University of Newcastle, Australia. In 1992 what was Shortland Electricity instigated a business unit known as Safearth Engineered Solutions, or Safearth, of which Darren was one of the original members. In the ensuing years that group grew to over 30 staff and in changed its name to Network Earthing. During that time Darren was involved in consulting, training and R&D. Before joining Safearth Consulting in 2011 as Principal Engineer, Darren’s roles included Development Manager and two years as Acting Principal Consultant. For over 20 years Darren has investigated and managed the risks associated with earthing/grounding, lightning protection and interference. The more notable projects include investigations of the Snowy Mountains Hydro Scheme, Pacrim West OFC interference, CLP interference in Hong Kong and a number of forensic investigations. In over 20 years working in earthing Darren has performed numerous injection tests for a business level that now averages an injection test per day. For more than two decades Darren has delivered formal earthing training, including over 20 earthing short courses for the ESAA/ENA across Australia, New Zealand and Asia. Darren has presented at numerous conferences including CIGRE and the IEEE. Darren recently co-delivered an appendix for AS2067 on earthing system testing and is the editor of the ENA Working Group tasked to publish on risk to telecommunications assets from power system earthing hazards.

Implications of Distributed Generation for Power Utility Protection Schemes when faults can be back fed! Will the topology have to change? (247)

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Woodhouse, D

Summers, T

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