Oral discussions on Session: “Control and protection” - Part I

Abstract

This paper contains the first part of the transcribed oral discussions of Session "Control and Protection" of the 2013 IREP Symposium -Bulk Power System Dynamics and Control, held on Tuesday morning, August 27, 2013. Papers [1]-[4] were presented. DiscussionChair: The floor is now open for questions.James Lyons (retired General Electric): For the last speaker [4]: There are three start-up companies in the USA right now working on distribution voltage control with low voltage power electronics. Two of them are pursuing UPFC type architecture with voltage series and shunt compensation, and there is also another initiative in California, called smart-inverter initiative, which is built on German experience. I am told that the shunt compensation, just VArs, doesn't work so well. And the fundamental issue on high penetration of PV in Germany etc. is cloud passing and then pumping up and down the distribution voltage. Can you comment on that? Have you thought through these types of controls? David Hill (Univ. of Sydney): Just really not much more than what I said. There are colleagues around me who are trying. They see the issues and they are taking a fresh approach. They tried some of the existing methods, like scaling down STATCOMs and similar approaches, that didn't work very well. So now, and I think that I know the initiative that you mentioned in California, they are starting all over again in a sense to design new controllers for low voltages. My point was that we need to follow that, and model them and include them in our coordination techniques. Hopefully, those controllers would be decentralized. You can't coordinate millions of things like that or even thousands perhaps but you can include them in your models of the higher voltage. J. Lyons: One of the claims made is, looking at series compensation that more isolates a sensitive load from the distribution medium voltage directly. That should be quite effective in controlling actual delivered voltage to given customers. So, when you have problematic customers on the distribution feeder and you can isolate a few of those, you can live with wider swing of the feeder voltage and keep everybody on.