I’m happy to explain what MATPOWER does with the inputs you give it, but I’m afraid I can’t answer whether or not your approach solves the problem you want to solve.
Best regards, Ray > On Mar 15, 2016, at 1:53 PM, Mounika Vanjarapu <[email protected]> > wrote: > > sir > by calculating like that,i find the elasticity value based on the > prices and demand at one bus and from that elasticity value i calculate > theoritically the load at other buses.and i get the value equal to the load > which i get when i run the power flow.is <http://flow.is/> it absolutely > wrong or there may be chances.please dont feel bad for my doubts > > On Tue, Mar 15, 2016 at 10:54 PM, Ray Zimmerman <[email protected] > <mailto:[email protected]>> wrote: > You are making it too complicated (and I confess I still don’t follow what > you are doing). > > This line of code … > > mpc=load2disp(mpc0,'mo',3,30); > > … simply means that you want the load at bus 3 to be curtailed if the nodal > price goes above $30. If the original price (with no curtailment) was $40, > you should expect the load to be curtailed. If you were to use, instead of > 30, something greater than 40, say 45, as the last argument to load2disp(), > then you should see no load curtailment and the solution should be identical > to the original solution. > > Ray > > > >> On Mar 15, 2016, at 11:37 AM, Mounika Vanjarapu <[email protected] >> <mailto:[email protected]>> wrote: >> >> sir >> actually, i run an ieee14 bus system and i get the nodal prices at the >> respective buses.i take the nodal price at 3rd bus as the marginal >> benefit,to reduce the load in that system,i write the code as >> mpc0=loadcase('case14o'); >> define_constants; >> >> mpc=load2disp(mpc0,'mo',3,30); >> and i take this 30 as my curtailable price at which the load has to >> curtail.for that i formulate as, >> previously i get the nodal price 40$/MWh.for high price the load >> has to curtail,so since 30 is a negative cost,i take it as 40+(40-30). >> ie.i take them as -40 and -30.so -30 is greater than -40 so load is >> curtailed.to <http://curtailed.to/> represent it in positive values i >> convert like this >> >> On Tue, Mar 15, 2016 at 8:52 PM, Ray Zimmerman <[email protected] >> <mailto:[email protected]>> wrote: >> I’m afraid I don’t understand your description of your view. I am only aware >> of two quantities involved … (1) the marginal benefit or value of the load >> which directly determines the “cost” of the negative generator used to model >> it, and (2) the nodal price computed by the OPF. (1) is an input, (2) is an >> output, and their relative values determine whether or not the load will be >> curtailed. >> >> So, I don’t understand what you mean by the $30 price you are setting. >> >> Ray >> >> >> >>> On Mar 14, 2016, at 11:48 AM, Mounika Vanjarapu <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> sir >>> thanks for reply.But i think this concept in a different view. >>> >>> i.e i take the marginal benefit cost as the one >>> which we get in the power flow.The price which we set is the high price we >>> are setting. we are representing them as negative costs.so i take it as for >>> example >>> the marginal benefit cost is 40$/MWh,the price we are >>> setting is 30$/MWh.since 30 is a negative cost,the total cost which >>> we we have to impose to the customer is 40+(40-30)=50$/MWh where >>> representing as positive cost. >>> Therefore the high price on the customer is 50$/MWh during >>> peak periods.Is it absolutely wrong view. >>> >>> On Mon, Mar 14, 2016 at 6:50 PM, Ray Zimmerman <[email protected] >>> <mailto:[email protected]>> wrote: >>> It is working as expected. The load will be curtailed when the price is >>> higher than the value you assign to the load. So if you assign a value of >>> $38, and the price is $40, it will be curtailed. If you assign the value to >>> $45, the load will not be curtailed at a price of $40. Essentially, you are >>> saying … this load should only be curtailed if the price goes above $45, so >>> you would not expect any curtailment at lower prices (like $40). >>> >>> Ray >>> >>> >>> > On Mar 12, 2016, at 5:08 AM, Mounika Vanjarapu >>> > <[email protected] <mailto:[email protected]>> wrote: >>> > >>> > sir >>> > i am using price sensitive loads concept.i select the bus 4th as my >>> > dispatchable load.before converting the loads to dispatchable the LMP at >>> > the 4th bus is 40.19$/MWh.now i set the curtailble price at 38 as >>> > mpc=loadcase('case14m'); >>> > >> mpc0=load2disp(mpc,'m',4,38); >>> > >> runopf(mpc0) >>> > >>> > MATPOWER Version 5.0b1, 01-Jul-2014 -- AC Optimal Power Flow >>> > MATLAB Interior Point Solver -- MIPS, Version 1.0.2, 01-Jul-2014 >>> > Converged! >>> > >>> > Converged in 0.10 seconds >>> > Objective Function Value = 6190.15 $/hr >>> > ================================================================================ >>> > | System Summary >>> > | >>> > ================================================================================ >>> > >>> > How many? How much? P (MW) Q (MVAr) >>> > --------------------- ------------------- ------------- >>> > ----------------- >>> > Buses 14 Total Gen Capacity 772.4 -52.0 to >>> > 148.0 >>> > Generators 5 On-line Capacity 772.4 -52.0 to >>> > 148.0 >>> > Committed Gens 5 Generation (actual) 220.2 71.2 >>> > Loads 11 Load 211.2 77.4 >>> > Fixed 10 Fixed 211.2 77.4 >>> > Dispatchable 1 Dispatchable 0.0 of 47.8 -0.0 >>> > Shunts 1 Shunt (inj) -0.0 20.7 >>> > Branches 20 Losses (I^2 * Z) 8.97 38.85 >>> > Transformers 3 Branch Charging (inj) - 24.3 >>> > Inter-ties 0 Total Inter-tie Flow 0.0 0.0 >>> > Areas 1 >>> > >>> > Minimum Maximum >>> > ------------------------- >>> > -------------------------------- >>> > Voltage Magnitude 1.011 p.u. @ bus 3 1.060 p.u. @ bus 1 >>> > Voltage Angle -13.69 deg @ bus 14 0.00 deg @ bus 1 >>> > P Losses (I^2*R) - 2.72 MW @ line 1-2 >>> > Q Losses (I^2*X) - 8.30 MVAr @ line 1-2 >>> > Lambda P 35.84 $/MWh @ bus 1 40.03 $/MWh @ bus 3 >>> > Lambda Q -0.08 $/MWh @ bus 1 0.56 $/MWh @ bus 14 >>> > >>> > ================================================================================ >>> > | Bus Data >>> > | >>> > ================================================================================ >>> > Bus Voltage Generation Load >>> > Lambda($/MVA-hr) >>> > # Mag(pu) Ang(deg) P (MW) Q (MVAr) P (MW) Q (MVAr) P >>> > Q >>> > ----- ------- -------- -------- -------- -------- -------- ------- >>> > ------- >>> > 1 1.060 0.000* 184.04 0.00 - - >>> > 35.838 -0.084 >>> > 2 1.041 -3.889 34.80 25.44 21.70 12.70 37.398 >>> > - >>> > 3 1.011 -10.790 1.33 28.24 94.20 19.00 40.026 >>> > - >>> > 4 1.018 -7.626 - - 0.00* -0.00* >>> > 38.762 0.161 >>> > 5 1.019 -6.692 - - 7.60 1.60 >>> > 38.380 0.220 >>> > 6 1.060 -12.021 0.00 9.97 11.20 7.50 >>> > 38.386 - >>> > 7 1.048 -10.804 - - - - >>> > 38.787 0.133 >>> > 8 1.060 -10.804 0.00 7.52 - - >>> > 38.787 - >>> > 9 1.045 -12.468 - - 29.50 16.60 >>> > 38.802 0.202 >>> > 10 1.040 -12.680 - - 9.00 5.80 >>> > 38.950 0.308 >>> > 11 1.046 -12.482 - - 3.50 1.80 >>> > 38.795 0.225 >>> > 12 1.045 -12.873 - - 6.10 1.60 >>> > 39.007 0.207 >>> > 13 1.040 -12.934 - - 13.50 5.80 >>> > 39.200 0.343 >>> > 14 1.024 -13.692 - - 14.90 5.00 >>> > 39.800 0.559 >>> > -------- -------- -------- -------- >>> > Total: 220.17 71.16 211.20 77.40 >>> > >>> > ================================================================================ >>> > | Branch Data >>> > | >>> > ================================================================================ >>> > Brnch From To From Bus Injection To Bus Injection Loss (I^2 >>> > * Z) >>> > # Bus Bus P (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q >>> > (MVAr) >>> > ----- ----- ----- -------- -------- -------- -------- -------- >>> > -------- >>> > 1 1 2 125.50 -6.03 -122.78 8.50 2.718 >>> > 8.30 >>> > 2 1 5 58.54 6.03 -56.86 -4.39 1.685 >>> > 6.96 >>> > 3 2 3 64.90 1.90 -63.07 1.21 1.834 >>> > 7.73 >>> > 4 2 4 39.83 0.18 -38.98 -1.19 0.853 >>> > 2.59 >>> > 5 2 5 31.15 2.16 -30.63 -4.25 0.518 >>> > 1.58 >>> > 6 3 4 -29.80 8.03 30.43 -7.74 0.632 >>> > 1.61 >>> > 7 4 5 -37.01 9.82 37.19 -9.22 0.189 >>> > 0.60 >>> > 8 4 7 28.90 -2.65 -28.90 4.28 0.000 >>> > 1.63 >>> > 9 4 9 16.65 1.76 -16.65 -0.35 0.000 >>> > 1.41 >>> > 10 5 6 42.69 16.26 -42.69 -11.86 0.000 >>> > 4.40 >>> > 11 6 11 6.48 4.18 -6.43 -4.08 0.050 >>> > 0.11 >>> > 12 6 12 7.69 2.60 -7.62 -2.45 0.072 >>> > 0.15 >>> > 13 6 13 17.31 7.54 -17.10 -7.12 0.210 >>> > 0.41 >>> > 14 7 8 -0.00 -7.43 0.00 7.52 0.000 >>> > 0.09 >>> > 15 7 9 28.90 3.15 -28.90 -2.30 0.000 >>> > 0.85 >>> > 16 9 10 6.09 3.58 -6.08 -3.55 0.015 >>> > 0.04 >>> > 17 9 14 9.96 3.20 -9.83 -2.93 0.127 >>> > 0.27 >>> > 18 10 11 -2.92 -2.25 2.93 2.28 0.010 >>> > 0.02 >>> > 19 12 13 1.52 0.85 -1.51 -0.85 0.006 >>> > 0.01 >>> > 20 13 14 5.12 2.17 -5.07 -2.07 0.049 >>> > 0.10 >>> > -------- >>> > -------- >>> > Total: 8.968 >>> > 38.85 >>> > >>> > ================================================================================ >>> > | Voltage Constraints >>> > | >>> > ================================================================================ >>> > Bus # Vmin mu Vmin |V| Vmax Vmax mu >>> > ----- -------- ----- ----- ----- -------- >>> > 1 - 0.940 1.060 1.060 518.860 >>> > 6 - 0.940 1.060 1.060 72.456 >>> > 8 - 0.940 1.060 1.060 79.294 >>> > >>> > ================================================================================ >>> > | Generation Constraints >>> > | >>> > ================================================================================ >>> > Gen Bus Active Power Limits >>> > # # Pmin mu Pmin Pg Pmax Pmax mu >>> > ---- ----- ------- -------- -------- -------- ------- >>> > 4 6 1.614 0.00 0.00 100.00 - >>> > 5 8 1.213 0.00 0.00 100.00 - >>> > >>> > Gen Bus Reactive Power Limits >>> > # # Qmin mu Qmin Qg Qmax Qmax mu >>> > --- --- ------- -------- -------- -------- ------- >>> > 1 1 0.084 0.00 0.00 10.00 - >>> > >>> > ================================================================================ >>> > | Dispatchable Load Constraints >>> > | >>> > ================================================================================ >>> > Gen Bus Active Power Limits >>> > # # Pmin mu Pmin Pg Pmax Pmax mu >>> > --- --- ------- -------- -------- -------- ------- >>> > 6 4 - -47.80 -0.00 0.00 0.351 >>> > >>> > Gen Bus Reactive Power Limits >>> > # # Qmin mu Qmin Qg Qmax Qmax mu >>> > --- --- ------- -------- -------- -------- ------- >>> > 6 4 4.868 0.00 0.00 3.90 - >>> > >>> > >>> > >>> > >>> > my doubt is when i set the price at 45 more than the price 40.19 which i >>> > get in normal power flow then the load is not curtailed. >>> > 1.the load should be curtailed for prices more than the marginal cost.but >>> > here the load is curtailed for less prices.why and what is the concept >>> > behind that. >>> >>> >>> >>> >> >> > >
