I’m not sure I understand your question. But you will need to run a power flow or OPF on island 1 in order to have a valid power flow solution with matching load and generation.
Ray > On Jul 6, 2017, at 3:39 AM, prem panigrahi <[email protected]> wrote: > > Dear Ray Sir > In my case i have 4 Island and remove the buses of 3 Island > having no generation and the Island 1 have a reference bus. In generation > side dispatched load is less than the capacity due to which there is a > mismatch in load and generation. Is it a natural case or I can manually > increase the dispatch load from generation unit. > > > > > > [GROUPS, ISOLATED] = case_info(mpc) > Checking connectivity ... 4 connected groups, 4 isolated buses > Elapsed time is 0.034766 seconds. > ================================================================================ > Full Island Island Island Island > > System 1 2 3 4 > > Number of: ---------- ---------- ---------- ---------- > ---------- > buses 57 45 3 3 2 > > loads 42 35 2 1 2 > > on 42 35 2 1 2 > > off - - - - - > > fixed 42 35 2 1 2 > > dispatchable - - - - - > > on - - - - - > > off - - - - - > > generators 7 7 - - - > > on 7 7 - - - > > off - - - - - > > shunt elements 3 2 1 - - > > branches 80 59 3 2 1 > > on 61 55 3 2 1 > > off 19 4 - - - > > ties (off) 14 12 4 3 2 > > > Load > active (MW) > dispatched 1375.9 1321.9 33.6 2.5 > 5.9 > fixed 1375.9 1321.9 33.6 2.5 > 5.9 > dispatchable - - - - - > > nominal 1375.9 1321.9 33.6 2.5 > 5.9 > on 1375.9 1321.9 33.6 2.5 > 5.9 > off - - - - - > > fixed 1375.9 1321.9 33.6 2.5 > 5.9 > dispatchable - - - - - > > on - - - - - > > off - - - - - > > reactive (MVAr) > dispatched 336.4 317.5 10.4 1.0 > 2.7 > fixed 336.4 317.5 10.4 1.0 > 2.7 > dispatchable - - - - - > > nominal 336.4 317.5 10.4 1.0 > 2.7 > on 336.4 317.5 10.4 1.0 > 2.7 > off - - - - - > > fixed 336.4 317.5 10.4 1.0 > 2.7 > dispatchable - - - - - > > on - - - - - > > off - - - - - > > > Generation > active (MW) > dispatched 928.9 928.9 - - - > > max capacity 1975.9 1975.9 - - - > > on 1975.9 1975.9 - - - > > off - - - - - > > min capacity - - - - - > > on - - - - - > > off - - - - - > > reactive (MVAr) > dispatched 193.3 193.3 - - - > > max capacity 699.0 699.0 - - - > > on 699.0 699.0 - - - > > off - - - - - > > min capacity -468.0 -468.0 - - - > > on -468.0 -468.0 - - - > > off - - - - - > > > Shunt Injections > active (MW) - - - - - > > reactive (MVAr) 21.6 11.6 10.0 - - > > > Branch Losses > active (MW) - - - - - > > reactive (MVAr) - - - - - > > > DC line > export (MW) > dispatch - - - - - > > max capacity - - - - - > > on - - - - - > > off - - - - - > > min capacity - - - - - > > on - - - - - > > off - - - - - > > > Reference Buses > num of ref buses 1 1 0 0 0 > > ref bus numbers 1 1 > > > > -------------------------------------------------------------------------------- > Isolated > Buses > Number of: ---------- > buses 4 > loads 2 > on 2 > off - > fixed 2 > dispatchable - > on - > off - > generators - > on - > off - > shunt elements - > branches - > on - > off - > ties (off) 7 > > Load > active (MW) > dispatched 12.0 > fixed 12.0 > dispatchable - > nominal 12.0 > on 12.0 > off - > fixed 12.0 > dispatchable - > on - > off - > reactive (MVAr) > dispatched 4.8 > fixed 4.8 > dispatchable - > nominal 4.8 > on 4.8 > off - > fixed 4.8 > dispatchable - > on - > off - > > Generation > active (MW) > dispatched - > max capacity - > on - > off - > min capacity - > on - > off - > reactive (MVAr) > dispatched - > max capacity - > on - > off - > min capacity - > on - > off - > > Shunt Injections > active (MW) - > reactive (MVAr) - > > Branch Losses > active (MW) - > reactive (MVAr) - > > DC line > export (MW) > dispatch - > max capacity - > on - > off - > min capacity - > on - > off - > > Reference Buses > num of ref buses 0 > ref bus numbers > > From: [email protected] > <mailto:[email protected]> > <[email protected] > <mailto:[email protected]>> on behalf of Ray > Zimmerman <[email protected] <mailto:[email protected]>> > Sent: Monday, July 3, 2017 9:15:52 PM > To: MATPOWER discussion forum > Subject: Re: DCOPF not converge > > Hi Prem, > > If you are solving each island individually, the DC OPF should converge as > long as (1) you have a reference bus in the island, (2) there is adequate > generation to cover the load in the island, and (3) the line constraints do > not prevent the generated power from reaching the loads. > > Ray > > >> On Jun 23, 2017, at 9:18 AM, prem panigrahi <[email protected] >> <mailto:[email protected]>> wrote: >> >> >> Dear All >> I am facing convergence problem during the calculation of DCOPF >> in IEEE buses. For my work I have fixed the capacity of transmission line >> 110% of initial power flow by changing the RATE_A field, then at each time, >> I increase the load and generation with a factor (1+alpha). I remove the >> lines whose power flow is more than their capacity. After the certain load, >> the grid divided into many parts. I tried to solve the island problem but >> dcopf not converged. I found on one island the dispatchable load is less >> than its generation. Should I take this situation as a blackout??. Please >> help me >> >> >> >> >> >> >> >> >> Prem Panigrahi >> Research Scholar >> India >> >> >> >> From: prem panigrahi <[email protected] >> <mailto:[email protected]>> >> Sent: Tuesday, June 20, 2017 6:13:37 PM >> To: [email protected] <mailto:[email protected]> >> Subject: DCOPF not converge >> >> Hello Sir >> >> In IEEE 57 bus, I fixed the capacity of transmission line and then increase >> the load and generation. I removed those lines whose power flow is more than >> their capacities. When the grid is divided into 4 parts. I remove the >> isolated buses. In island 1------- 45 buses are there including 7 >> generators. Matpower automatically considers the slack bus. But the DCOPF >> doesn't converge as the generation has a capacity of 1975.9 MW, but it >> dispatches only 928.9 MW. So there is a mismatch in load and generation. >> Load requirement is 1321.9 MW. Is there any mistake that I am doing? . >> <result.txt>
