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Title: Electromagnetic fast-transients in LV networks with ubiquitous small-scale embedded generation
Author: Clark, David
ISNI:       0000 0004 2733 9821
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2012
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Small-scale embedded generation projects rated below 16A per phase are being integrated into low-voltage distribution networks in ever increasing numbers. Seen from the network operator's perspective as little more than negative load, the commissioning of such generators is subject to compliance with the Fit and Forget connection requirements of ENA Engineering Recommendation G83/1. This thesis has sought to quantify the electromagnetic switching transient implications of integrating very large volumes of embedded generation into the UK's low-voltage supply networks. Laboratory testing of a converter-interfaced PV source has been undertaken to characterise typical switching transient waveshapes, and equivalent representative source models have been constructed in EMTP-ATP. A detailed frequency-dependent travelling wave equivalent of the DNO-approved Generic UK LV Distribution network model has been developed and, by means of extensive statistical simulation studies, used to quantify the cumulative impact of geographically localised generators switching in response to common network conditions. It is found that the magnitude of generator-induced voltage and current transients is dependent on the number of concurrently switched generators, and on their relative locations within the network. A theoretical maximum overvoltage of 1.72pu is predicted at customer nodes remote from the LV transformer terminals, for a scenario in which all households have installed embedded generation. Latent diversity in switch pole closing and inrush inception times is found to reduce predicted peak transient voltages to around 25-40% of their theoretical maxima.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering