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Thread: Generator load-shedding scheme

  1. #1
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    Generator load-shedding scheme

    Hello, I'm an electrician installing a 6-panel QS system. My generator can't supply the entire load (400a) of the house and I'm working with my Lutron vendor to come up with a load shedding scheme. We've been toying with a few ideas, any input and/or advice is much appreciated.

    Software implementation: I provide a dry contact to my vendor that closes (or opens if he likes) upon 'trouble' and that would cause certain loads that we deem 'unessential' to become deactivated and locked out from use. Ideally there would be an override by the panels if customer needed/wanted to turn on some of the shed loads. I understand that the Illumination line had something like this; can/should this be implemented in QS software?

    Hardware implementation: We map all 'unessential' loads so they are all in the same panel(s) and I put a 100a contactor before each unessential panel and de-energize the panel(s) during 'trouble'. As an aside the transfer switch transfers the full service over, not individual branch circuits hence the contactor is used.

    many thanks for your time and responses

  2. #2
    Do you have an AMX, Crestron, Savant or Control4 system on the job? If so I would work with that system integration platform to control your additional relays for load shedding. Use that system's software to control and provide feedback for your hardware via its IOs and relays to control your relays with additional relays to supply the IO feedback.
    VAV
    Danbury, CT

  3. #3
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    Quote Originally Posted by scopp View Post
    Hello, I'm an electrician installing a 6-panel QS system. My generator can't supply the entire load (400a) of the house and I'm working with my Lutron vendor to come up with a load shedding scheme. We've been toying with a few ideas, any input and/or advice is much appreciated.

    Software implementation: I provide a dry contact to my vendor that closes (or opens if he likes) upon 'trouble' and that would cause certain loads that we deem 'unessential' to become deactivated and locked out from use. Ideally there would be an override by the panels if customer needed/wanted to turn on some of the shed loads. I understand that the Illumination line had something like this; can/should this be implemented in QS software?

    Hardware implementation: We map all 'unessential' loads so they are all in the same panel(s) and I put a 100a contactor before each unessential panel and de-energize the panel(s) during 'trouble'. As an aside the transfer switch transfers the full service over, not individual branch circuits hence the contactor is used.

    many thanks for your time and responses
    When you refer to 'panels' and 'loads' in your description, are you talking about Lutron Dimming Panels and Lighting Loads or are you talking about Breaker/Distribution Panels and Branch Electrical Circuits? I'm pretty sure you're talking about the former, but I wanted to check.
    If the load shedding you are looking for is strictly Lutron Dimming Panels & Loads, I would probably use your hardware solution.
    From my own experience- get the right size generator. We have 1 client with an undersized generator and partial backup to the home's electrical service and they are miserable. I'm sure this has been presented to the client but it's the best solution I can think of.

  4. #4
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    Quote Originally Posted by scopp View Post
    Hello, I'm an electrician installing a 6-panel QS system. My generator can't supply the entire load (400a) of the house and I'm working with my Lutron vendor to come up with a load shedding scheme. We've been toying with a few ideas, any input and/or advice is much appreciated.

    Software implementation: I provide a dry contact to my vendor that closes (or opens if he likes) upon 'trouble' and that would cause certain loads that we deem 'unessential' to become deactivated and locked out from use. Ideally there would be an override by the panels if customer needed/wanted to turn on some of the shed loads. I understand that the Illumination line had something like this; can/should this be implemented in QS software?

    Hardware implementation: We map all 'unessential' loads so they are all in the same panel(s) and I put a 100a contactor before each unessential panel and de-energize the panel(s) during 'trouble'. As an aside the transfer switch transfers the full service over, not individual branch circuits hence the contactor is used.

    many thanks for your time and responses

    There are a few things to look it prior to spitting out solutions.

    I don't think adding an additional vendor into the mix is a solution such as AMX Crestron or Control4. I see no value there as any conditional programing they can offer can all be done in QS if you were take the road of software solution. QS has the ability to utilize CCI/CCO control on its own.

    I don't think a hardware solution is the first choice either. Using a contractor to drop out an RPM to me sounds good on the surface but really limits your control later for over riding loads.

    Some details to keep in mind prior to programing
    Im sure the generator will exercise weekly so keep in mind the closure comes only after transfer switch has actually transferred not during exercise period. Unless of course you are exercising under load.

    What types of Loads are we shedding from with in QS are some of these load controlled by time clocks (could disable tome clocks for those) are they mostly turned on from keypads or local switches ?

    How experienced is your Lutron programmer with conditional programing


    The reason I ask this is because my first thought process on this would be to have CCI from generator signal QS to a specific green mode (Labeled Generator Mode) that scene could force all loads to any desired level (Unaffected, 50%,Off...). If a majority of the loads were controlled by keypads we could have the CCI also set a variable and use that variable to not allow certain buttons on keypads to work so those loads couldn't be turned on. We could have multiple variables were some keypad buttons will work only if a over ride switch/Button was hit. Im sure there is 10 ways to accomplish what you want and keep it user friendly just a matter of programming.

    Not sure of the generator/transfer switch you are using but I know ONAN and Kohler offer a load shedding CCO where when generator reaches a certain percentage of load it will give you a closure. We could use that to actually control a second Generator mode to shed more non priority loads.

    I have some ideas but some more info would be helpfull

  5. Likes scopp liked this post
  6. #5
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    Here's another way I would state my response-
    If I'm the lutron programmer on a job and the GC asked me: Do you want your programming to be responsible for balancing the generator load, or should we hardwire the electrical circuits so that the generator never sees a draw higher than its capacity? My response- wire the generator properly first, and then we can talk about complicated solutions to lighting the house with an undersized generator. On many jobs the first call comes to us as the Lutron providers, including burnt out lamps. I do not want to be seen as the first link in the chain when a generator fails. If there is enough generator capacity to power half the Lutron Panels and those panels are balanced so every room has sufficient lighting on generator power, I think that's a great hardware solution. If the client wants more light then they need a bigger generator.

  7. #6
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    Quote Originally Posted by digit1 View Post
    Here's another way I would state my response-
    If I'm the lutron programmer on a job and the GC asked me: Do you want your programming to be responsible for balancing the generator load, or should we hardwire the electrical circuits so that the generator never sees a draw higher than its capacity? My response- wire the generator properly first, and then we can talk about complicated solutions to lighting the house with an undersized generator. On many jobs the first call comes to us as the Lutron providers, including burnt out lamps. I do not want to be seen as the first link in the chain when a generator fails. If there is enough generator capacity to power half the Lutron Panels and those panels are balanced so every room has sufficient lighting on generator power, I think that's a great hardware solution. If the client wants more light then they need a bigger generator.
    One could look at it like that and there is nothing wrong with your solution,Taking your response one step further one could argue that if you can afford a QS system surely you could afford a bigger generator. Not knowing the electricians situation with his service and real estate needed to put in a larger generator and transfer switch there is always more then one way to satisfy the client. However as both the electrical contractor and the programmer I feel I can offer my clients a turn key solution while still maintaing a quality job.

  8. #7
    Quote Originally Posted by mcignarella View Post
    There are a few things to look it prior to spitting out solutions.

    I don't think adding an additional vendor into the mix is a solution such as AMX Crestron or Control4. I see no value there as any conditional programing they can offer can all be done in QS if you were take the road of software solution. QS has the ability to utilize CCI/CCO control on its own.
    The conditional logic you can accomplish in QS doesn't compare at all to what is capable in a system like AMX or Crestron. You can also achieve a superior GUI for the client to view status and control the system, you can even display the current amperage levels being drawn at various points with additional componants. Obviously if there isn't such a system already spec'd I wouldn't add one just to accomplish this but if there is one spec'd that's where the logic should be, not in QS. Chances are that in a house with six rpm panels they'll also have a system to integrate all the sub systems in the house like Lutron, AV, hvac, etc.
    VAV
    Danbury, CT

  9. #8
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    Quote Originally Posted by vining View Post
    The conditional logic you can accomplish in QS doesn't compare at all to what is capable in a system like AMX or Crestron. You can also achieve a superior GUI for the client to view status and control the system, you can even display the current amperage levels being drawn at various points with additional componants. Obviously if there isn't such a system already spec'd I wouldn't add one just to accomplish this but if there is one spec'd that's where the logic should be, not in QS. Chances are that in a house with six rpm panels they'll also have a system to integrate all the sub systems in the house like Lutron, AV, hvac, etc.
    Vining

    Correct you could do what you mentioned but at a heavy price its the main reason I didn't go down that path for this poster based on his post.Of course we could add current transformers on every load to see the draw and make some fancy GUI interface to see that and control that.We could buy a module for serial interface to series 7000 ASCO transfer switch get all kinds of status from that too its endless. Not sure what the hourly rate you charge for Crestron programing vs Lutron but what you mentioned is well above most peoples budget for the limited use that feature would have in my opinion Moreover now we have at least 2 if not 3 vendors meddling with load shedding In my experience that turns into a lot of finger pointing when things fail to work as planned.Keeping it simple under one hat can be accomplished with QS because of the non integrated parts of the electrical standby setup explained. However for what you mentioned and the cost we could get a bigger generator and do the entire residence and skip all this load shedding. My suggestion was simply to keep it with limited hardware and programing within 1 vendor. The logic required to accomplish what the poster asked could easily be handled within QS if one chose to go down that path. Of course if we were using Crestron we could take 100 steps further as you explained. I respectfully disagree that adding another system(i know u were implying that) or using existing sub system for this simple logic into the mix to handle a simple load shedding issue would over complicate this specific situation the poster asked about. Keeping the existing generator existing transfer switch and rpm loads as is could be accomplished. With that said we could talk for hours on how layout this job from the beginning,shedding A/C loads via Crestron or shedding loads via Tekmar stats such as we do with Crestron and with QS I might add an so on and so on.The possibilities are endless on what we can do with system such as Crestron,AMX and Savant. Keeping in mind QS was designed for lighting control it can be expanded in some situations to handle simple automation tasks. Im very familiar with the capabilities of Crestron being a certified Crestron dealer also with that experience I know what equipment and programing time costs. I just didn't see the need to even offer that type of a solution based on posters questions. Im glad you did because buy us discussing this kind of stuff does allow others to see what"s capable in home automation. If he had a sub system he was capable of using I would hope he would have had that as an option listed. If he does have such a system and would like advice on how to meet his clients expectations we all could give many ideas and most likely all of them would be good ones. At the end of the day we are here on this forum to help people with learning the programing and abilities of Lutron QS and sharing our experiences in the home automation arena.

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  11. #9
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    Thanks for your reply and sorry for the delayed response. I believe there is a Savant system to be installed. Didn't know Savant offered this type of functionality. I'll look into it. Thanks much.

  12. #10
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    Quote Originally Posted by mcignarella View Post
    There are a few things to look it prior to spitting out solutions.

    I don't think adding an additional vendor into the mix is a solution such as AMX Crestron or Control4. I see no value there as any conditional programing they can offer can all be done in QS if you were take the road of software solution. QS has the ability to utilize CCI/CCO control on its own.

    I don't think a hardware solution is the first choice either. Using a contractor to drop out an RPM to me sounds good on the surface but really limits your control later for over riding loads.

    Some details to keep in mind prior to programing
    Im sure the generator will exercise weekly so keep in mind the closure comes only after transfer switch has actually transferred not during exercise period. Unless of course you are exercising under load.

    What types of Loads are we shedding from with in QS are some of these load controlled by time clocks (could disable tome clocks for those) are they mostly turned on from keypads or local switches ?

    How experienced is your Lutron programmer with conditional programing


    The reason I ask this is because my first thought process on this would be to have CCI from generator signal QS to a specific green mode (Labeled Generator Mode) that scene could force all loads to any desired level (Unaffected, 50%,Off...). If a majority of the loads were controlled by keypads we could have the CCI also set a variable and use that variable to not allow certain buttons on keypads to work so those loads couldn't be turned on. We could have multiple variables were some keypad buttons will work only if a over ride switch/Button was hit. Im sure there is 10 ways to accomplish what you want and keep it user friendly just a matter of programming.

    Not sure of the generator/transfer switch you are using but I know ONAN and Kohler offer a load shedding CCO where when generator reaches a certain percentage of load it will give you a closure. We could use that to actually control a second Generator mode to shed more non priority loads.

    I have some ideas but some more info would be helpfull
    Many thanks for your reply, and apologies for the delayed response.

    The loads to be shed are controlled exclusively from keypads and to my knowledge are not controlled by timeclocks (though I'd leave the option open). No local switches (except for maintenance areas).

    I'm using a Cummins genset, very well-made unit. Upon quick glance looks like it doesn't have a shed CCO, just 'emergency', distinguished from 'exercise'.

    Not sure how experienced...

    My mechanical engineer will shed most of the building's (heat pump, stage 1) load upon closure, and though there might be enough headroom for all the lighting I'm just making sure everything's landed properly before finish...

    many thanks again

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