John Fletcher (49Min)

UNSW School of Electrical Engineering and Telecommunications

Abstract

Note: if you would like to see what is inside of an inverter, John's team has a video ELEC9711 - Inside a PV Inverter

Australia is a global leader in small scale distributed generation with more that 2 million installations of solar PV systems, connected to the grid through inverters, typically in the 2-50kW range. As distributed generation starts to have a considerable impact across all parts of the power system, the need for accurate load models is of paramount importance. However, the load models currently in use around the world are outdated and do not provide a reliable representation of the response of inverter-based distributed generation.

There is a great variety of manufacturers and inverter models currently used across the country. Although all inverters comply with local standards (AS 4777.3-2005 and 4777.2-2015), actual grid conditions rarely match the prescriptive tests defined in these standards. Furthermore, inverter responses to different grid disturbances exhibit great diversity. As a consequence, a unique load model might fail to emulate actual inverter behaviours, occurring due to voltage sags, frequency deviations, phase jumps or re-energisation after disconnections. In this uncertain scenario, inverter bench-testing is a key process to determine inverter performance in a broad range of grid events, as well as to provide accurate inputs to load modelling.

The presentation will provide a summary of the benchmarking of solar PV inverters currently undertaken at UNSW Sydney, as part of the UNSW - AEMO – ARENA project on “Addressing Barriers to Efficient Renewable Integration”. It will also highlight the challenges and provide a reference concerning the needs requirements of future inverter-based generation and associated standards in Australia and around the world.

Brief Bio

Professor John Fletcher received the B.Eng. (first class Hons.) and Ph.D. degree in electrical and electronic engineering from Heriot-Watt University, Edinburgh, U.K., in 1991 and 1995, respectively. Until 2007, he was a Lecturer with Heriot-Watt University. From 2007 to 2010, he was a Senior Lecturer with the University of Strathclyde, Glasgow, U.K. He is currently a Professor with the University of New South Wales, Sydney, Australia. His research interests include distributed and renewable integration, silicon carbide electronics, pulsed-power applications of power electronics, and the design and control of electrical machines. Prof. Fletcher is a Charted Engineer in the U.K. and a Fellow of the Institution of Engineering and Technology.