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LED inrush current and generator set

Julien Leblanc
Hello,


I'm currently working on a sport field application where i need to power some LED reflectors (30 kW total).

I will also use a generator set, in case the network fails.


The inrush current of the reflectors is 3 times higher than their rated current, but the duration is only 0.2ms.


Could anybody tell me if i should take into account the inrush current when I choose the generator set power (that is, to oversize the generator)?

Or i should ignore the inrush current and set the power of the generator a bit higher than the total power of the reflectors?

I'm not talking about the circuit breakers of generator's outputs. Let's say one can choose them so that they don't trip.

If those breakers don't trip, is it possible that anything else happen to the generator set, because of the inrush current?


I've been searching through the specifications of many generator sets, but i cannot find any data on this specific problem (short overload).






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    Harry Macdonald:

    While I agree with the comment about the time taken to get the generator up and running, it might focus minds to ask what is the acceptable time for the place to be in total darkness. Most battery backed emergency lighting systems are short break transfer, i.e. sub one second of darkness.You might get a gen set up and running in less than 5 seconds for the first part of the load, 10 seconds for all the load. Is this acceptable? If not then additional battery backed lighting adds a whole new layer of complexity.

    Is it acceptable to be in complete darkness? How dark will it ever really be? Is the lighting is for safe evacuation or can folk simple stay where they are for 10 secs?



    After a mains failure, the lights (at least a part of them) should become available in 5 s. I think it is not realistic with a genset.

    As i read in some specifications, the ATS doesn't start the generator immediately, but after t1= 5 s of delay, necessary to ensure that there is a true power failure. 

    After the start, another t2=5 s are necessary to warm up the engine... That makes a total of 10s.

    Unless t1 can be set to zero, but in this case the genset would start even in the case of a very short power failure and I'm not sure if it's ok.

    Given that the sport events are rather rare, the starting of the genset due to false alarms would be acceptable?

    Or even keeping the genset running, is it customary to do so?



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  • 0
    Harry Macdonald:

    While I agree with the comment about the time taken to get the generator up and running, it might focus minds to ask what is the acceptable time for the place to be in total darkness. Most battery backed emergency lighting systems are short break transfer, i.e. sub one second of darkness.You might get a gen set up and running in less than 5 seconds for the first part of the load, 10 seconds for all the load. Is this acceptable? If not then additional battery backed lighting adds a whole new layer of complexity.

    Is it acceptable to be in complete darkness? How dark will it ever really be? Is the lighting is for safe evacuation or can folk simple stay where they are for 10 secs?



    After a mains failure, the lights (at least a part of them) should become available in 5 s. I think it is not realistic with a genset.

    As i read in some specifications, the ATS doesn't start the generator immediately, but after t1= 5 s of delay, necessary to ensure that there is a true power failure. 

    After the start, another t2=5 s are necessary to warm up the engine... That makes a total of 10s.

    Unless t1 can be set to zero, but in this case the genset would start even in the case of a very short power failure and I'm not sure if it's ok.

    Given that the sport events are rather rare, the starting of the genset due to false alarms would be acceptable?

    Or even keeping the genset running, is it customary to do so?



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