This presentation will provide an insight into modelling of distribution networks, a subject that is typically not given much attention in undergraduate power systems engineering courses at universities and technical institutes. A general overview of necessary tasks and sources of network data for electricity distribution network and resulting benefits to the utility and their customers of accurate network modelling will be shared at this presentation. Network modelling enables load flow, short circuit, reliability, voltage sags, harmonic distortion, electromagnetic transients, protection device coordination studies to be performed for identification of least cost solutions to various issues encountered in prudent management of a distribution network. The quality of supply and customer relationship management using results obtained from distribution network modelling will also be discussed. Results of both modelling and continuous power quality monitoring of network will be presented for short circuit and voltage sag measurements. Summary of data from continuous harmonic voltage distortion monitoring will be presented with a view to find answer to an unexplained trend. Finally, new technical challenges facing the distribution utilities will be discussed.
Ashok Parsotam is of Indian descent born in Fiji Islands. He graduated from the University of Auckland with Bachelors in Engineering - Electrical and Electronics in 1986. Ashok started his engineering career at the Fiji Electricity Authority in 1986 where he was responsible for the tariff metering section which was responsible for testing of accuracy of tariff meters before being installed. During his tenure he developed very simple yet very reliable and accurate method of establishing accuracy of tariff metering installations at low voltage and high voltage polyphase metering system installed at customers premises. His method identified many incorrect installations resulting in either under-metering or over-metering of installations. In 1988, Ashok migrated to New Zealand and worked for Southpower and from 1998 Vector Ltd, Auckland - the largest electricity distribution utilities in South Island and North Island, as Special Projects Engineer where he modelled 66kV, 33kV and 11kV distribution network for the very first time performing load flow and short circuit studies for planning and operational needs of the organisation. He also worked on power systems earthing and was involved with the development of power and telecommunication coordination standards. There he also had opportunity to liaise with professors and lectures at the University of Canterbury and gained insight into power quality fields such as harmonics. He also worked on understanding voltage sags and it's impact on customers' equipment, modelling single core underground cables for earth potential rise and earth fault studies. In 2009, Ashok moved to Australia where he is working for Ausgrid - an electricity distribution utility in New South Wales servicing Sydney and Newcastle regions. Ashok have been involved with network modelling, power quality and power systems earthing and made various contributions at industry level and to standards bodies in Australia and New Zealand.