Dear Dr Ray, Thanks for the explanations. Kind regards
Idris From: [email protected] [mailto:[email protected]] On Behalf Of Ray Zimmerman Sent: 10 January 2012 14:40 To: MATPOWER discussion forum Subject: Re: AC power flow for multiple generators MATPOWER's power flow does not currently handle distributed slack, so the only time it makes sense to specify more than one slack bus is in an islanded system, where you need one in each island. If you set multiple reference buses in a fully connected network, it will distribute the slack among the two buses as required to make the voltage angles at both buses equal to the specified angles (probably not what you want). Also, as you have seen, currently if there are multiple generators at a reference bus, all of the slack is assigned to the first generator. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jan 10, 2012, at 7:14 AM, Idris Musa wrote: Dear all, I want run AC power flow, considering multiple generators with possibility of Islanding using MATPOWER 4.1. In addition to the grid supply I have five generators of equal output capacity at particular bus location. I defined this bus location as slack bus. This means I have two slack buses (including the grid supply). When I run MATPOWER AC power flow, with the grid connected, one of the generators (the first generator of the five connected) is taking care of system losses, showing that the chosen generator has unlimited capacity and is also absorbing negative active power. I am assuming a distributed generator (which could be synchronous generator, fuel cell etc) is this physically feasible? I had expected the grid supply been the first slack bus to take care of the system losses and provide other support for the network. I would be glad if someone could advice on how to go about it. Idris Musa
