Dear Angelina, I had a similar experience when running my 62 bus network, until i did voltage compensation. I suggest you look through your network and see if there is any buses that may need compensator, if thats the case you may need to have them in the network at appropriate points for the solver to converge, because if there could be a constant violation of voltage limits then convergence may not be achieved.
On 29 January 2014 17:35, Angelina <[email protected]> wrote: > Dear Dr Zimmerman, > > I am trying to solve an ac opf with the mips solver (560) in a lightly > meshed 6.6 kV distribution system of 32 branches. The range for the > reactances is [0.05-1.9 pu], whereas some of them have almost negligible > values. When I am solving the simple ac power flow the problem converges > with no problems to be appeared. However, when I am trying to solve the > same problem with optimal power flow, assigning some costs to the > generators, the ac opf fails numerically or the message ' the matrix is > singular to working precision, the results may be inaccurate' appears. > > I suspect that the problem is the solver. Could you recommend me another > solver to use? > > Any guidance would be appreciated. > > Kind Regards, > > Angelina > -- *Fred Kanjelesa.*NCC-Trading/ZESCO Zambia/Lusaka. Mobile: +260967/955-880912 Extension: 5124 "I can do all things through Christ who strengthens me." *Philippians 4:13*
