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 Post subject: SKM, ETAP, Easypower, or EDSA?
PostPosted: Fri Oct 30, 2015 4:09 pm 

Joined: Tue Oct 13, 2015 5:10 pm
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Hi,

I am a recent graduate and conducting my first AC Arc Flash study :shock: and need advice on which power software to purchase. What I’m most interested in is the ease of use and time saving capabilities. I work for a consulting company where time is really of the essence but I also want to generate quality work. The projects I’ll be dealing with will range between 0.48 kV to 15 kV. Any advice? :D

-Reggie


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Sat Oct 31, 2015 12:15 pm 
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First off a study involves much more than just the software. There are many decisions that go into the analysis. One item that you need to be concerned with is the quality of the data collection.

If you have not done so, you should:

1. Read IEEE 1584-2002
2. Read NFPA 70E-2015
3. Take a class on arc flash studies (the forum host teaches them)
4. Decide what else you are going to use the software for, for example, Harmonic studies, motor starting, etc.
5. Based on #4, may lead you to eliminate one software
6. Get evaluation copies of the software and try it out.
7. If this is a one time study for your firm, it may be less expensive to sub-contract it as I think the minimum package price is around $10k

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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Sun Nov 01, 2015 8:09 pm 
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ReggieBrenden wrote:
Hi,

I am a recent graduate and conducting my first AC Arc Flash study :shock: and need advice on which power software to purchase. What I’m most interested in is the ease of use and time saving capabilities. I work for a consulting company where time is really of the essence but I also want to generate quality work. The projects I’ll be dealing with will range between 0.48 kV to 15 kV. Any advice? :D

-Reggie


You may also consider ARCAD's short circuit fault current and arc flash hazard analysis and labeling software programs and mobile apps for the ease of use, accuracy and price tag.

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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Mon Nov 02, 2015 9:16 am 
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Location: Colorado
Reggie,
I am not saying one is better than the other, they all do the job. I have used 3 of the 4 but use SKM the most mainly because I have become most familiar with and have a good relationship with several of the people there. I also like ETAP, it has features the one one do not. It has been 10 years since using EDSA. Most of it is client driven. We have also rented software so we can do specific project - not a great way to evaluate mainly because the one you take a class on is the one you get familiar with.

I have preferential leanings but that is because my company has standardized on SKM
BUT we lots of other software (some of it is in the $10,000/yr ++ range) and use the one the client requests.

Research them all, call them and get the sales pitch, call some of your friends and see what they use and have them ask why.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Mon Nov 02, 2015 1:07 pm 

Joined: Mon Nov 10, 2014 11:01 am
Posts: 23
I use SKM software and have few complaints. I will handle large systems. I did a study on the system for an international airport which included many of the field facilities such as runway lighting systems.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Mon Nov 09, 2015 6:56 am 
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Posts: 154
I agree with everything the previous post said. He's hit on several important items. I'd suggest you also ask about technical support. But frankly, it's difficult to know how well a software package works if you've not used the software long. We use Easy Power and our experience with the tech support folks as well as cost for support has been good. Personally I like Easy Power, but it has issues like all software and it doesn't do everything perfectly - but what software does?

The previous comment about data gathering is dead on. The data gathering is as important - I'd argue even more important than the software. If the data is screwed up or incomplete, going back to can be difficult and/or costly. So I'd ask who's doing the data gathering for your firm? Will you subcontract that part or do it yourselves? Both options have serious concerns that need to be explored before going one way or the other.

Another consideration is your firm's liability. Before jumping into this field, talk with your firm's lead people and attorney. I'd council you not to wait to explore the liability question.

Good luck,


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Fri Nov 13, 2015 4:32 pm 

Joined: Tue Oct 13, 2015 5:10 pm
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Thanks for all the feedback everyone. Just to update all of you, my firm ended up purchasing ETAP. I’m still fairly new to this so I was wondering if anyone here has experience using the software. Are there any good tips you can provide? I am going to use the tutorials online to help me get started.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Sat Nov 14, 2015 6:53 am 
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ReggieBrenden wrote:
Thanks for all the feedback everyone. Just to update all of you, my firm ended up purchasing ETAP. I’m still fairly new to this so I was wondering if anyone here has experience using the software. Are there any good tips you can provide? I am going to use the tutorials online to help me get started.


Curious to know why you went with ETAP? Did you try out demo versions of all the software prior to making a decision?

Tutorials are one way to get started. It may be worthwhile to find a class offered by ETAP to start also.

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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Thu Nov 19, 2015 5:26 pm 

Joined: Tue Oct 13, 2015 5:10 pm
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Hi WBD,

It actually wasn't my decision. I was still evaluating all three softwares when one of my team members moved forward with ETAP. He said he had prior experience with it.

What software are you currently using if you don't mind me asking?


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Fri Nov 20, 2015 6:08 am 
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I use 3 software packages.
ArcPro - for utility type equipment and for compliance with OSHA 1910.269
SKM & EasyPower for all the others.

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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Wed Mar 02, 2016 12:34 pm 

Joined: Tue Oct 13, 2015 5:10 pm
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Hi I know it's been a while. So...I've been using the ETAP software now for almost 5 months. I'm starting to become comfortable using the software since I've done a couple projects already. I do plan on taking a training class just to solidify what I already know. Has anyone here taken a class with ETAP before? I just wanna know if it's worth it and also if you would recommend it for a rookie like me :P

-Reggie


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Tue Mar 08, 2016 8:08 am 
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What you really need to do is to take a class in power system analysis. The reason is that it is not really practical to do for example a SPICE or EDSA model of everything. That's way too detailed. So there are a whole bunch of empirical formulas and short cuts that deliver results that are within 1-2% of the actual answer without the high level stuff. These short cuts are actually in the ANSI, IEC, and IEEE standards.

You should be perfectly capable of doing the calculations WITHOUT the power system analysis software. That way you can recognize when the results it is giving you are incorrect and what to do for situations where you can't just plug in numbers.

THEN take the class in the power system analysis software. In that class you will learn all the little tricks that help you do things more quickly and efficiently, and again recognize what is going on when something isn't working correctly. But if you go into the class without the theoretical/engineering foundation, you won't get as much as you could out of the class.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Tue Mar 08, 2016 11:37 am 
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You may also consider ARCAD's Short Circuit Analytic (SCA V1.0) software program for short circuit fault current calculations and Arc Flash Analytic (AFA V5.0) for arc flash analysis and labeling. The SCA V1.0 is based on the comprehensive method for short circuit analysis, factors in both active and reactive parts of equipment impedance and takes into account contributions from multiple sources including motors and generators. Please note that some industry accepted calculation techniques ignore equipment X/R ratios in the analysis and apply different correction factors to equipment ratings. Disregarding the equipment X/R ratio introduces up to 15% uncertainty in a single step of adding two impedances alone while applying different correction factors does not quantifies and does not corrects the error but only amplifies it. Also,l beware of calculation short cuts including infinite bus assumption. Making assumption of infinite bus will result in most inaccurate short circuit fault current values in your equipment.


Last edited by wbd on Tue Mar 08, 2016 2:46 pm, edited 1 time in total.
Link to commercial website


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Tue Apr 05, 2016 12:08 pm 

Joined: Fri Feb 13, 2015 11:54 am
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Location: Alaska
I have sworn by SKM PTW since the late '80s when it was still called Captor and Dapper (i.e., before Windows), but that was just because it was the tool I was most familiar with. Lately I have been using ETAP because that is what my current employer had standardized on. I find very little difference between the two in terms of performance or capabilities for doing routine industrial power system design and analysis. The argument between the two is like arguing which is better, Apple or Android? They both get the job done, and they each have their own strengths and weaknesses.

My main complaint with both ETAP and SKM PTW is that neither company seems to have done much to improve the basic load flow/short circuit analysis models from the early days when they were written in Fortran77. They both still carry the same bus matrix size limitation as they did in the mid-1980s when an engineering workstation had only 640kB of RAM and a 20MB hard drive was considered excessive. OK - they max out at 5000 buses now, when 20 years ago they could only handle 3000, but hey...

The 5000 bus limitation is a serious drawback. Any component where there is a voltage drop consumes a virtual bus on either end; this pertains to every cable, transformer, line reactor, bus duct, and any other modeled device on the system where Ohm's Law applies. Any moderately large industrial power system quickly exceeds this limit and the model must be broken into multiple sub-models for analysis. Not a huge issue, but something to keep in mind.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA?
PostPosted: Fri Apr 08, 2016 6:18 am 
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Device86 wrote:
My main complaint with both ETAP and SKM PTW is that neither company seems to have done much to improve the basic load flow/short circuit analysis models from the early days when they were written in Fortran77. They both still carry the same bus matrix size limitation as they did in the mid-1980s when an engineering workstation had only 640kB of RAM and a 20MB hard drive was considered excessive. OK - they max out at 5000 buses now, when 20 years ago they could only handle 3000, but hey...


PTW's limitations are now based on the size of your wallet. If you want to go to 10,000 buses, just pay more money.

The issue is that the math has not changed from twenty years ago. Whether the problem space is load flow or short circuit, ultimately what you have is a matrix that has to be solved and depending on the type of power system analysis it can require an iterative calculation. Although matrix problems can be parallelizable, iterative calculations by nature are not since each iteration depends on the previous iteration. The general solution is obviously O(N^2) but in practice with extremely large matrices (over about 50+ rows & columns) the FFT algorithm can be used to reduce it to O(N log N). Also in practice the matrix is sparse and in most cases banded so it can be reduced to O(N) or very close to O(N) in practice but due to the way that small changes affect the overall results, it pushes for recalculating the entire matrix after every change which is computationally intensive. At best we may recognize that most of the nodes have no branches and converting each of these nodes into a single node so that the general matrix contains only buses with branches which requires the more complex general solver with the unbranched nodes materialized and solved separately. This would significantly reduce the overall size of the calculations involved.

To get better we would have to first accept that the results are all approximations anyways and given what we are doing, this should be a no-brainer. Then we can set a target of say <1% error for approximation purposes and calculate a shadow matrix that represents the effect that parameter changes to the matrix have on the overall result. Then as changes are made the algorithm can automatically determine the extent to which the change may affect the entire network. If the change results in less than 1% error then the change is not propagated. Otherwise, it propagates to the next part of the network. In this larger matrix the same approximation check is made again, which determines whether or not to "bubble up" the result. The overall result would be a much more responsive system that could potentially even be implemented on lower end hardware (e.g. cell phones).

PTW allows you to do something like this in practice by doing a "windowed" calculation where the recalculation is done on only a small part of a user-selected portion of the overall matrix. Doing a windowed update on say a single MCC occurs almost instantly compared to 20-30 minutes calculation time to update the short circuit estimate for a network of 3,000 nodes.

An inherent problem with what you are describing though, "breaking it into smaller networks" is that you are manually doing what I'm describing. For instance if I have a large operation with a very stiff main/utility bus I can first convert the loads into lumped parameter models and simulate the "main" by itself. Then I can treat each area branching off from the main/utility bus as separate networks.


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 Post subject: Re: SKM, ETAP, Easypower, or EDSA? EA-PSM Electric Software
PostPosted: Thu Jan 09, 2020 1:34 pm 

Joined: Thu Jan 09, 2020 1:31 pm
Posts: 1
I would recommend use EA-PSM ELectric software, which have all needed functionality to calculate power flow, short circuit, protection coordination and arc flash


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