Dear Ray,

Thank you very much for your help. The problem caused by the fact, that the 
physical ramp limits in the gen matrix (RAMP_10, RAMP_30 …) were set to zero.

Kind regards,


> On 20 Sep 2016, at 20:53, Ray Zimmerman <> wrote:
> Well, it is possible that it is simply the solution with least expected cost. 
> If, for instance, other generators have large ramping or redispatch costs, it 
> can be optimal to simply not use a generator that may fail in order to avoid 
> redispatch costs. On the other hand, physical ramp limits (RAMP_10 in the gen 
> matrix) can also prevent the dispatch from differing in the contingency and 
> base states. Large redispatch or reserve costs on the generator in question 
> can also be a possible cause (I know you said you tried zero reserve costs, 
> so that shouldn’t be the cause in this case). One more idea … is the 
> generator so expensive that it isn’t used at all, even if NOT modeling 
> contingencies?
>    Ray
>> On Sep 20, 2016, at 12:01 PM, Rusch Maurus <> wrote:
>> Dear all,
>> I am currently trying to model generator contingencies in MOST. However, my 
>> problem is, that there is no variation of generator dispatch over all the 
>> modelled states. The generators with a contingency assigned have therefore 
>> zero dispatch in the base and contingency state. Consequently I get no 
>> differences between the base case and the states in which contingencies do 
>> occur.
>> Moreover I have applied the same set up to model transmission line 
>> contingencies. This setup doesn’t cause any problems and I am getting 
>> different power flows in the base state and the states with contingencies.
>> In my setup, I have assigned a big amount of positive/negative reserve 
>> quantities with zero reserve costs to the generators with modelled 
>> contingencies. I have already tried to define contingencies for all kind of 
>> generators (different maximum capacity, different marginal costs). The 
>> system I am simulating consists of 940 buses, 4500 generators and 1350 
>> transmission lines.
>> Did someone have the same problem? What could be the reason that I don’t get 
>> any differences in generator dispatch among the modelled states?
>> Thank you very much for any kind of inputs and advices
>> Maurus Rusch

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