I've been working with a 240-bus system for the past year or so, adding energy storage and running OPFs, and I can second what Ray has already said. For my system I added a dispatchable load and conventional generator, choosing to turn one off and the other on depending on the mode of operation. My work involves the economics of energy storage so I've been using the smartmarket module included in the MATPOWER distribution.
I haven't been doing any multi-period optimization but one of my labmates (Zhouxing Hu) has and his papers can be found on IEEEXplore. Multi-period optimization is very computationally intensive and I wouldn't recommend heading down that path unless it is very important to your work. I've done exactly as Ray suggested and created a few algorithms that tell the energy storage when to charge/discharge, at what power is should operate, how much energy it can absorb/inject. A lot depends on how much detail you want to put into the battery model. Do you want to worry about energy storage capacity? Efficiency? Behavior of the battery as a function of state-of-charge? As you might expect, the sky is the limit on how much detail you put into the model. Trevor Hardy Wichita State University From: [email protected] [mailto:[email protected]] On Behalf Of Ray Zimmerman Sent: Wednesday, April 16, 2014 8:08 AM To: MATPOWER discussion forum Subject: Re: Including OLTC transformers and batteries for OPF calculation MATPOWER's OPF will not adjust the taps on the OLTC automatically, so you would have to do something like running the OPF multiple times, changing the tap values according to some search algorithm that attempts to find the optimal value. For the battery storage, an optimal scheduling involves making tradeoffs across time, which the single period OPF does not handle. So the simplest thing is probably to do some off-line work to come up with the charging/discharging schedule for the battery and simply enter that into your OPF as a fixed injection (generator with PMIN=PMAX, or as a load). Another option would be to include the battery storage as a generator with negative PMIN (charging) and positive PMAX (discharging), where these limits are adjusted to reflect the state of charge (discharging rate limited by available stored energy, charging rate limited by available unused capacity) and the gencost for the unit should be set to reflect your current estimates of the impacts of charging/discharging now on the total costs across time. I.e. Something like ... for charging, (cost of charging now + lost opportunity cost of being able to charge later - benefit of discharging in the future), for discharging (benefit of discharging now - benefit of discharging in the future). -- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Apr 15, 2014, at 11:40 PM, mnbester <[email protected]<mailto:[email protected]>> wrote: Hello, I am new to the Matpower environment and I was wondering if someone could provide assistance. I wish to run the OPF function on a distribution system, however in the system of interest, there is an OLTC transformer and a large scale battery storage system in addition to generators. Is there any way I can go about including these features within the OPF? Thank you for your time, any help would be much appreciated. Mandy.
