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 Post subject: New to Arc Flash, Short Circuit and Coordination studies
PostPosted: Mon Jul 25, 2016 7:02 pm 
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Hi. I currently work as an Engineer in the energy management field. I would like to branch off in to doing Arc Flash, Short Circuit and Coordination Studies. How would I go about doing this. I have been exposed to these reports but have never done them before. Would any of you happen to have any training material on how to get started? From what I've read I should learn how to do these reports manually then look in to getting software to aid with the reports. Not sure if it matters or not but I'm located in Canada. Thanks.


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 Post subject: Re: New to Arc Flash, Short Circuit and Coordination studies
PostPosted: Tue Jul 26, 2016 4:13 am 
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jhanbhaia wrote:
Hi. I currently work as an Engineer in the energy management field. I would like to branch off in to doing Arc Flash, Short Circuit and Coordination Studies. How would I go about doing this. I have been exposed to these reports but have never done them before. Would any of you happen to have any training material on how to get started? From what I've read I should learn how to do these reports manually then look in to getting software to aid with the reports. Not sure if it matters or not but I'm located in Canada. Thanks.


Power system analysis is a deep subject. Some parts of it (particularly the ANSI short circuit method which was specifically developed to be done by hand) can be done by hand and years ago, that's how it was done. But the accuracy demanded by arc flash studies in particular makes doing it without software essentially impossible for anything but the simplest of systems.

Second there is the whole issue of doing risk assessment studies which you didn't even mention. This isn't a particularly deep subject in terms of doing a lot of calculations but the theory behind it definitely takes some time and understanding, never mind getting used to and implementing a particular methodology.

You can theoretically get the IEEE Color books series and understand power system analysis from there, and one or two of the better text books. This covers everything except arc flash. From there you should be able to develop your own software using one of the off-the-shelf sparse matrix libraries to write the software and off you go. I think there's even a free open source one (PSE) floating around. Then you get into the whole issue of building up a library of all the circuit parameters that are hidden away all over in various manufacturers documentation plus a few more text books. This doesn't even touch on developing CAD software and reporting software interfaces to produce the reports you need. So clearly writing your own is a nonstarter here as is doing all the calculations by hand.

Mind you I'm not suggesting that you don't go this route but you can start to get an idea of the amount of work involved in trying to do everything by hand and using the software as an aid. You actually do need some of this theoretical background though because all the software out there produces odd results and you need to recognize and understand what is going on and how to fix it when this happens. The software is a tool for doing the calculations. You can't expect to just plug some things into it and get meaningful results back out. There are tons of parameters to enter and configure, and entry errors are common. Part of the job of doing an arc flash study is checking the computer-generated output for errors.

So while I'm on the one hand suggesting that while doing the calculations by hand is theoretically possible, it's not practically possible. But if you don't have the skill to theoretically do it, then you should NOT be practically doing it because otherwise you can't recognize when there are errors and correct them. Garbage in = garbage out.

And for arc flash you can attend for instance one of Jim Philips classes on doing power systems analysis. For risk assessments, attend one of the CCPS (Center for Chemical Processing Safety) classes. The third item is of course to purchase one of the software packages out there for doing the power system analysis and attending one or more of their training classes because believe me from not doing this at first, especially the first major package and most popular one out there (SKM), the learning curve is very steep. It is not practical to simply purchase the software and start using it out of the box. Most of the time you are working inside of a CAD system that is essentially a display of a database. The database documents the power system. From there you run the analysis programs and generate reports (and work within the reports...like Crystal Reports) off of the analysis results or the database. Because it isn't direct manipulation, you need to understand what's going on...hence the extra class(es).


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 Post subject: Re: New to Arc Flash, Short Circuit and Coordination studies
PostPosted: Tue Jul 26, 2016 7:56 am 
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PaulEngr wrote:
jhanbhaia wrote:
Hi. I currently work as an Engineer in the energy management field. I would like to branch off in to doing Arc Flash, Short Circuit and Coordination Studies. How would I go about doing this. I have been exposed to these reports but have never done them before. Would any of you happen to have any training material on how to get started? From what I've read I should learn how to do these reports manually then look in to getting software to aid with the reports. Not sure if it matters or not but I'm located in Canada. Thanks.


Power system analysis is a deep subject. Some parts of it (particularly the ANSI short circuit method which was specifically developed to be done by hand) can be done by hand and years ago, that's how it was done. But the accuracy demanded by arc flash studies in particular makes doing it without software essentially impossible for anything but the simplest of systems.

Second there is the whole issue of doing risk assessment studies which you didn't even mention. This isn't a particularly deep subject in terms of doing a lot of calculations but the theory behind it definitely takes some time and understanding, never mind getting used to and implementing a particular methodology.

You can theoretically get the IEEE Color books series and understand power system analysis from there, and one or two of the better text books. This covers everything except arc flash. From there you should be able to develop your own software using one of the off-the-shelf sparse matrix libraries to write the software and off you go. I think there's even a free open source one (PSE) floating around. Then you get into the whole issue of building up a library of all the circuit parameters that are hidden away all over in various manufacturers documentation plus a few more text books. This doesn't even touch on developing CAD software and reporting software interfaces to produce the reports you need. So clearly writing your own is a nonstarter here as is doing all the calculations by hand.

Mind you I'm not suggesting that you don't go this route but you can start to get an idea of the amount of work involved in trying to do everything by hand and using the software as an aid. You actually do need some of this theoretical background though because all the software out there produces odd results and you need to recognize and understand what is going on and how to fix it when this happens. The software is a tool for doing the calculations. You can't expect to just plug some things into it and get meaningful results back out. There are tons of parameters to enter and configure, and entry errors are common. Part of the job of doing an arc flash study is checking the computer-generated output for errors.

So while I'm on the one hand suggesting that while doing the calculations by hand is theoretically possible, it's not practically possible. But if you don't have the skill to theoretically do it, then you should NOT be practically doing it because otherwise you can't recognize when there are errors and correct them. Garbage in = garbage out.

And for arc flash you can attend for instance one of Jim Philips classes on doing power systems analysis. For risk assessments, attend one of the CCPS (Center for Chemical Processing Safety) classes. The third item is of course to purchase one of the software packages out there for doing the power system analysis and attending one or more of their training classes because believe me from not doing this at first, especially the first major package and most popular one out there (SKM), the learning curve is very steep. It is not practical to simply purchase the software and start using it out of the box. Most of the time you are working inside of a CAD system that is essentially a display of a database. The database documents the power system. From there you run the analysis programs and generate reports (and work within the reports...like Crystal Reports) off of the analysis results or the database. Because it isn't direct manipulation, you need to understand what's going on...hence the extra class(es).


Thanks for the in depth reply. My minor was in power system analysis so I'm no stranger to short circuit calculations. I also have used ETAP before so I have an understanding of how the software works. Are there resources online that can adequately prepare you to carry our Arc Flash, Short Circuit, Coordination, and Risk assessment studies? Attending the seminars in the US would prove to be difficult since I'm located in Ontario, Canada.


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 Post subject: Re: New to Arc Flash, Short Circuit and Coordination studies
PostPosted: Tue Jul 26, 2016 11:05 am 
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jhanbhaia wrote:

Thanks for the in depth reply. My minor was in power system analysis so I'm no stranger to short circuit calculations. I also have used ETAP before so I have an understanding of how the software works. Are there resources online that can adequately prepare you to carry our Arc Flash, Short Circuit, Coordination, and Risk assessment studies? Attending the seminars in the US would prove to be difficult since I'm located in Ontario, Canada.


OK, you've already overcome the hard engineering part.

I'll let Jim speak for himself on the issue of a local (Ontario) class. Even in the States it is rare to have a power system analysis class being taught close by. Terry Becker (ESPS) might also be able to point you in the direction of someone local. If you are up to speed on power system analysis then the only trick with arc flash calculations is that the software programs usually they use essentially just an IEC impedance type of short circuit calculation without using any of the usual shortcuts and assumptions. If you already have access to and know how to use ETAP then there's no reason to go further there.

IEEE 1584 itself does not specify how to determine the bolted fault current or the opening time, only that it is a required input. IEEE 1584 just uses the results from the short circuit study for estimating arcing current and uses the results from the coordination study to estimate opening time. These inputs along with some basic equipment-specific information go into estimating incident energy. If you want to get a flavor for what is involved, the annexes in CSA Z462 have copies of the procedure and the equations. I really recommend reading IEEE 1584 itself if you can get a copy but at the prices they charge, it is hard to justify purchasing it unless you use it frequently. I only had a copy because my predecessor at one company obtained a copy at some point and left a printed copy behind.

Risk assessments are new to the electrical world but are common in "dangerous" industries such as petrochemical plants or nuclear. Each industry tends to have it's own standards and methods for "how to do it". I suggested CCPS LOPA because it's the most compatible with electrical hazards. They sell text books and even online courses on the subject. It is best to get a trained facilitator to lead an assessment. I've been through the training close to half a dozen times for various standards and industries and facilitated a lot of risk assessments of my own. I can honestly say that given a standard I can train operators, electricians, and mechanics in about 15 minutes to get them up to speed enough to participate in a formal session. Learning the entire system takes about a week. The hourly personnel are very good at identifying very common hazards that have actually occurred while engineers are better at finding obscure hazards that are system-oriented in nature.

In the end you are not really doing anything more complex than reconstructing the risk table in Z462 except that you are tailoring it to a specific site. It sounds simple and frankly it is but there are a lot of nuances to getting it right and for liability reasons it is best to follow an existing documented standard for doing so.


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 Post subject: Re: New to Arc Flash, Short Circuit and Coordination studies
PostPosted: Tue Aug 02, 2016 12:10 pm 
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PaulEngr wrote:
jhanbhaia wrote:

Thanks for the in depth reply. My minor was in power system analysis so I'm no stranger to short circuit calculations. I also have used ETAP before so I have an understanding of how the software works. Are there resources online that can adequately prepare you to carry our Arc Flash, Short Circuit, Coordination, and Risk assessment studies? Attending the seminars in the US would prove to be difficult since I'm located in Ontario, Canada.


OK, you've already overcome the hard engineering part.

I'll let Jim speak for himself on the issue of a local (Ontario) class. Even in the States it is rare to have a power system analysis class being taught close by. Terry Becker (ESPS) might also be able to point you in the direction of someone local. If you are up to speed on power system analysis then the only trick with arc flash calculations is that the software programs usually they use essentially just an IEC impedance type of short circuit calculation without using any of the usual shortcuts and assumptions. If you already have access to and know how to use ETAP then there's no reason to go further there.

IEEE 1584 itself does not specify how to determine the bolted fault current or the opening time, only that it is a required input. IEEE 1584 just uses the results from the short circuit study for estimating arcing current and uses the results from the coordination study to estimate opening time. These inputs along with some basic equipment-specific information go into estimating incident energy. If you want to get a flavor for what is involved, the annexes in CSA Z462 have copies of the procedure and the equations. I really recommend reading IEEE 1584 itself if you can get a copy but at the prices they charge, it is hard to justify purchasing it unless you use it frequently. I only had a copy because my predecessor at one company obtained a copy at some point and left a printed copy behind.

Risk assessments are new to the electrical world but are common in "dangerous" industries such as petrochemical plants or nuclear. Each industry tends to have it's own standards and methods for "how to do it". I suggested CCPS LOPA because it's the most compatible with electrical hazards. They sell text books and even online courses on the subject. It is best to get a trained facilitator to lead an assessment. I've been through the training close to half a dozen times for various standards and industries and facilitated a lot of risk assessments of my own. I can honestly say that given a standard I can train operators, electricians, and mechanics in about 15 minutes to get them up to speed enough to participate in a formal session. Learning the entire system takes about a week. The hourly personnel are very good at identifying very common hazards that have actually occurred while engineers are better at finding obscure hazards that are system-oriented in nature.

In the end you are not really doing anything more complex than reconstructing the risk table in Z462 except that you are tailoring it to a specific site. It sounds simple and frankly it is but there are a lot of nuances to getting it right and for liability reasons it is best to follow an existing documented standard for doing so.


Thanks for the breakdown I really appreciate it!


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