1. It is no different than any other generator … by “dummy generator” I just 
meant that it is not a real generator but is included to represent something 
else.
2. I’m sorry, you are correct. Even in this case the cost of the generator 
needs to be set equal to the load’s marginal benefit minus the incentive.

   Ray


> On Mar 17, 2016, at 2:27 PM, Mounika Vanjarapu <[email protected]> 
> wrote:
> 
> sir
> my questions are
> 1.is <http://1.is/> there any special representations for dummy generator or 
> just to add a generator in the generator data and add the cost in gencost 
> data.
> 2.according to my concept,when the incentive is more or there is more bill 
> credit then the load should be curtailed.but in this case if the generator is 
> low cost then it is scheduled.if it is high cost then it is not scheduled.
>                      how it can meet my problem
> 
> On Thu, Mar 17, 2016 at 10:29 PM, Mounika Vanjarapu 
> <[email protected] <mailto:[email protected]>> wrote:
> I understand the concept behind that but my doubt is how to represent a dummy 
> generator  in matpower like coding or editing the code.
> 
> On Thu, Mar 17, 2016 at 10:23 PM, Ray Zimmerman <[email protected] 
> <mailto:[email protected]>> wrote:
> Suppose a particular bus has a 100 MW load and a 100 MW generator that is 
> dispatched at 25 MW. That is equivalent to a 75 MW load and the cost of the 
> 25 MW of generation can be considered as the cost of curtailing 25 MW of the 
> nominal 100 MW load.
> 
>     Ray
> 
> 
>> On Mar 17, 2016, at 12:43 PM, Mounika Vanjarapu <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> k sir.
>> and how to represent a dummy generator.when i include  a generator at one 
>> bus,it is also scheduled as per opf formulation.and how the load will be 
>> curtailed by using this.
>> 
>> On Thu, Mar 17, 2016 at 10:07 PM, Ray Zimmerman <[email protected] 
>> <mailto:[email protected]>> wrote:
>> I’m afraid I can’t answer the question of whether or not your particular 
>> problem formulation implements the “time of use” program you intend.
>> 
>>     Ray
>> 
>> 
>>> On Mar 17, 2016, at 12:01 PM, Mounika Vanjarapu <[email protected] 
>>> <mailto:[email protected]>> wrote:
>>> 
>>> thanx for replying sir and i will try this.  one more clarification i need 
>>> from you.
>>>                           I implement time of use program for congestion 
>>> management.ie <http://management.ie/> for different periods the price will 
>>> be different .for example peak and off peak,valley periods.
>>> 1.I take the case of ieee14 bus system and i create congestion by 
>>> decreasing the line flow limit at 3rd bus to 30MW where the actual power 
>>> flow is 39.77MW.so <http://39.77mw.so/> there will be congestion 
>>> occured.therefore the LMP values will increase.
>>> 2.In order to mitigate this condition I use the scale load function and 
>>> scale the load into peak ,off peak and valley periods in the ratio of 
>>> 0.55,0.3,0.15 resp. at all buses.
>>> 3.Now i use price sensitive loads concept where I assume the marginal 
>>> benefit is 28.5$/MWh,above that pirce the load should be curtailed.
>>> 4.In peak periods the load is curtailed and I show the gencost,objective 
>>> function,demand cost comparisons by not applying time of use.
>>>                    My question is am i using the price sensitive loads in a 
>>> correct way in my context of time of use program are I am violating.I mean 
>>> that, is my approach  for implementing time of use program using price 
>>> sensitive loads is in a correct way.
>>>             Please suggest me,i need advice from you.
>>> 
>>> 
>>> On Thu, Mar 17, 2016 at 7:47 PM, Ray Zimmerman <[email protected] 
>>> <mailto:[email protected]>> wrote:
>>> I can think of two essentially equivalent ways to do this. 
>>> 
>>> (1) Model the loads as fixed loads at their nominal values plus a dummy 
>>> generator that represents curtailment. The cost of curtailment is then 
>>> included directly as a positive cost for these curtailment dummy generators.
>>> 
>>> (2) Model your load as a dispatchable load with a benefit function equal to 
>>> the benefit to the load minus the curtailment payment from the ISO.
>>> 
>>> For a DC OPF there should be no difference between the two approaches. For 
>>> an AC OPF the only difference is that (1) affects real power only, but (2) 
>>> forces the power factor of the load to remain constant, so reactive power 
>>> is curtailed in proportion to the real power curtailed.
>>> 
>>>    Ray
>>> 
>>> 
>>> 
>>> 
>>>> On Mar 16, 2016, at 10:10 PM, Mounika Vanjarapu 
>>>> <[email protected] <mailto:[email protected]>> wrote:
>>>> 
>>>> sir
>>>>     coming to direct load control program where the case is to give 
>>>> incentives to the customers for load reduction,the objective function 
>>>> should includes the incentives payment along with the generators 
>>>> cost.whereas showing the price sensitive loads the objective function 
>>>> removes the payment by the loads.presently in matpower the runopf does 
>>>> this.
>>>>                           my question is can we change our objective 
>>>> function according to our problem in matpower.why because ISO have to pay 
>>>> money to the people for their curtailment.so i want to includes this money 
>>>> in my objective function.
>>>> 
>>>> On Wed, Mar 16, 2016 at 7:51 PM, Ray Zimmerman <[email protected] 
>>>> <mailto:[email protected]>> wrote:
>>>> Since MATPOWER represents dispatchable demand as negative generation with 
>>>> negative cost, the objective function ends up being the negative of net 
>>>> benefits. Normally you want to maximize net benefits (total benefit to 
>>>> demand minus total cost of supply). MATPOWER does this by minimizing the 
>>>> negative of net benefits. So a negative objective function silly means 
>>>> that the benefits to the loads is greater than the cost to generators … 
>>>> which is what you normally expect.
>>>> 
>>>>     Ray
>>>> 
>>>> 
>>>> > On Mar 16, 2016, at 5:13 AM, Mounika Vanjarapu 
>>>> > <[email protected] <mailto:[email protected]>> wrote:
>>>> >
>>>> > sir
>>>> >
>>>> > what does  it means a negative objective function.
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 
> 

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