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Incident Energy Study

What Can I Do With Incident Energy Studies?

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esp into featured imageToday, I will outline three things you can do with a completed incident energy study. Completing these tasks is an important part of any electrical safety plan, and will reduce the risks to employees performing work on energized equipment. This will also reduce the risk of an arc flash incident occurring.

Identify Key Problem Areas

An incident energy study will show you where the incident energy is dangerously high in your facility. Now that you know the incident energy on a particular bus is high, you can analyze your power system with this information in mind, and try to answer the following two questions:

  1. Why is the incident energy at this location so high?
  2. Can the incident energy at this location be lowered somehow to provide a safer working environment?

Establish Working Boundaries and Select Warning Labels

arc-flash2
An example of a warning label

Once you’ve answered the questions about your key problem areas, you might determine that the incident energy level cannot be reduced any farther. From here, what you can do is use the information in your incident energy study to establish safe working boundaries and acquire warning labels. The incident energy study should indicate the likelihood of an arc flash event occurring. Knowing the risks, you can assign appropriate working boundaries for the tasks involved with energized equipment. The incident energy study should have different “levels” assigned to each piece of equipment that is a part of the study. These levels correspond to recommended working distances, and you can use these levels to label all of your equipment so that every worker understands the risks of working on energized labelled equipment.

Select Appropriate PPE For the Job

Now you can use your newfound knowledge of the safe working boundaries to select the appropriate PPE for any job that takes place in your facility. The same levels that you used to

An example of PPE

determine working boundaries can also be used to determine PPE requirements. If for example you must work closer than the recommended working boundary, the incident energy study will recommend the level of PPE required for doing energized work at different working distances.
In order to determine what PPE you need, you’ll have to use the relevant standards. CSA Z462 in Canada and NFPA 70E in the USA both have extensive tables describing what
appropriate PPE is for the various levels of incident energy on a work site. It is important to also adhere to any and all local and regional standards for your area.
An incident energy study is required for determining safe working boundaries and PPE for the work site. Thanks for reading! If you enjoyed this article, sign up for our newsletter for more content like this, and share this article with your colleagues with buttons below.

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4 Ways to save money with a power system analysis at your pulp and paper mill

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Paper Mill
Sometimes it seems that the number of requirements for running a plant keeps going up, and regulations keep changing cutting into the bottom line. This is how a lot of clients I have worked with in the past have approached getting a power system analysis completed, they needed labels on their equipment to satisfy the requirements of CSA Z462 and NFPA 70E, so they needed an arc flash study. It was an expense, nothing more.
However, if you define the scope (the first step in performing a power system analysis) smartly, you can duplicate effort without duplicating cost, and use the report to make smart decisions that will either save money immediately or identify capital projects with very fast payback.

1. Reduced number of Electrical Safety Incidents

According to NFPA (source-pdf) the average shock or arc flash injury event can cost $80k in direct costs, if indirect costs are included this can be much higher. However, according to that same paper there are no valid ratios to estimate this.
With a power system analysis in hand, an effective electrical safety program can be developed that will directly affect the number of these incidents. The number of these incidents are typically very low, however the high cost of a single incident will pay for the power system analysis and electrical safety program many times over.

2. Better preventative maintenance program

Motor with pump industry in factory
Competitive pulp and paper mills have at least a preventative maintenance program, and a lot are moving to a predictive maintenance program. The most important part of these programs, like a valid power system analysis, is the quality of input data. When going through the process of validating all the input data for a power system analysis, it would be a simple matter of gathering the information for your maintenance program without duplicating effort. It is likely the same staff that will be doing the work in anycase.
With better information, including short circuit values, expected load flow voltages, etc, you can feed this information into the maintenance program and understand when equipment may fail, allowing you to plan its replacement without affecting the process.

3. Power Quality Improvements

When going through the system and gathering all the necessary input data for the incident energy study, you have all the inputs for proper load flow study, and all you need is some existing load information that can be gleaned from the power meters throughout your mill.
This is where you will see an opportunity to get the most value from the power system analysis. Like most industrial plants you are likely charged:

  • a energy fee (MW-HR),
  • a peak charge (rolling MW) and
  • sometimes a power factor charge.

You can minimize your power factor and energy fees by making sure that you are running your system as close to unity power factor as possible. With a proper power flow study, you will be able to identify areas within you plant that would be best suited for adding power factor correction capacitors and quickly identify the potential payback.

4. Update Drawings of the System

Finally, and likely an over-looked part, is that you will have updated drawings as part of your power system analysis that are very accurate, current, as-built conditions. These drawings are now trusted inputs for any capital or maintenance projects that may take place in the future.
IMG_0004One of the biggest risks to integrating into any existing system, is the quality of the existing documents, and the cost of having a consultant on site developing as-built drawings will increase the cost of a small project quickly. Having these drawings on hand, and assuming you have a document control procedure in place, the consultant replacing a motor or adding a new system will have the best information starting, reducing the design time, construction issues, and start-up concerns.

Next Steps

If you like what you read consider joining our newsletter where you will get every post in your inbox at the start of the month. You will never miss a thing.  If you would like to learn more about how a power system analysis can help you manage your system better and safer, contact us here, or visit our services page here.
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What is Arc Flash? (and Why You Need to Label)

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Arc Flash Hazard is one of the three hazards that are directly associated with electricity, the other two being shock and arc blast.

CSA Z462-15 defines Arc Flash as:

a dangerous conditions associated with the possible release of energy caused by an electric arc.

When there has been a breakdown in equipment insulation, whether from equipment failure or an electrical worker coming into contact when working on energized electrical equipment.

What Arc Flash Looks Like


The video above is an example of an arc flash in a 100A disconnect, it demonstrates the immense energy released and a typical application.

3 Side Benefits of an Arc Flash Study

There are tons of reasons to have a current Arc Flash Study, and an Electrical Safety Program, here are three side benefits that you may not have thought of include:

Electrical panel with cables in the old factory
Hope your doors are attached

  1. As-Builts – When was the last time you incorporated all the redlines associated with your power system?
  2. Enclosure Audit – Are you sure all your equipment enclosures have their doors secured? Are there latches missing?
  3. Document Switching Configurations – Knowing the valid switching configurations for the facility is critical for the study, but not every plant has these written down for the operators.

Labels

The Canadian Electrical Code (rule 2-306) requires labels on all electrical equipment that may require energize work to have a warning label that an Arc Flash and Shock Hazard is present.  However, that alone doesn’t provide enough information to ensure that the electrical worker opening that panel can select the appropriate PPE. Below is an oversized example of a typical label we would recommend.
Arc Flash Label
It includes all the information that is recommended by CSA Z462 and is easily read and can be audited without much effort.  The top warning and first header line is all that is required by the Canadian Electrical Code, the remainder of the information provided allows a trained electrical worker to select the appropriate PPE for the task at hand.

Next Steps

Here I outlined a couple of simple reasons why you should have a current Arc Flash Study – or complete Power System Analysis – for your plant. Over the next few weeks I will be outlining the differences of the why and hows for various plants. Be sure to sign up for our newsletter below so you won’t miss a single post. And if you liked what you saw be sure to share with your network.
If you have any questions about what you read here, please don’t hesitate to contact me through the contact page here.
Regards,
Jeff MacKinnon, P.Eng.,PE

How to best use the Power System Study Report

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If you have gone through the process of completing the power system study report, or have had an outside consultant provide you a binder with all the deliverables, now the real work begins. Having a power system study completed is not the end: it is the start. The reasons to have a power system study report completed in the first place can vary from getting incident energy values for PPE selection, to future plant expansions.

Study Report
Use the power system study report to save money and have a reliable facility.

In this article we will outline some of the more common uses of a complete power system study report. We’ll also include suggestions about how to approach the recommendations that were included.

Short Circuit Study

Let’s start at the beginning with the short circuit study. The first thing we will look at is the type of recommendations that you will be expecting to receive in the report. First there is going to be any equipment that is not rated for the existing short circuit current that is available within the facility. There are a couple of reasons for this to happen: the first is that the equipment was purchased undersized, however the more likely scenario is that there have been system changes. These changes could be either at the utility level – adding additional transmission capacity – or within the facility itself.
Typically the best way to fix these issues is to replace the equipment.
Another output of the short circuit study will be areas that are marginal. This could mean that a change in the system could exceed the fault rating on the affected equipment. For these, investigate the switching scenario that was used, and figure out if there are any additions to the plant planned in the future.  A decision will then be made to determine if the equipment should be replaced now, or flagged as an area of concern when there are system configuration changes in the future.

Protection Coordination Study

Time Current Curve Example
TCC from an ETAP example file

The protection coordination study will likely include recommendations for areas that are mis-coordinated. With the help of your consultant you can go through the areas of concern and develop a list of what needs to be changed.  With proper selective coordination, the system will operate in a predictable manner in the event of a fault or overload.
In a lot of cases it will be easy to change the settings on the relay, or LSI(G) breaker, to solve the coordination problem. If the settings can’t be changed with the existing equipment, the protection device will need to be replaced. If the mis-coordination is something that will not affect a large portion of the system, or is the same circuit (a primary fuse and secondary breaker on a transformer) the decision may be to leave the mis-coordination as it is.
Another consideration of selective coordination is the incident energy in the case of an arc flash event. Clearing the fault as quickly as possible will limit the heat energy available, and will reduce the arc flash boundary and PPE required for energized work.  These decisions will be simplfied when going through the electrical safety program.

Incident Energy Study

The incident energy study is a critical input to the arc flash analysis, which is a critical portion of the electrical safety program. If you haven’t developed an electrical safety program or an arc flash risk analysis,  a great way to start one is with an incident energy study in hand. With the incident energy known at all the equipment, you will know the arc flash boundary and can start developing PPE levels for energized work.

The Electrical Safety Program is critical workplace safety
The Electrical Safety Program is critical to workplace safety

Arc Flash Risk Analysis

The first step is to develop a risk assessment as associated with the arc flash hazard. Within the company develop a list of the various tasks that will expose workers to an arc flash hazard. From there you can determine what incident energy is considered too high of a risk for energized work, and cross-reference with the incident energy report. You can implement mitigation techniques for any areas that have a high incident energy.

Incident Energy Mitigation Techniques

There are only two methods to lower the incident energy at a bus: one is to lower the time the arc is present before being cleared, and the other is to lower the magnitude of the current.  To shorten the time that the arc is present, modifying the protection settings will work well. Sometimes this may mean sacrificing selective coordination, which is a compromise that can be made on a case by case basis.
It is harder to lower the available current. You can add impedance – add inductance or more cable – which is typically not practical, or break up the large motors onto different buses to lessen the back feed current during a fault. Neither of these are very practical, and are typically ignored.

Load Flow Study

Power system study reports can help you save money by saving energy.
A load flow study can help save energy and save money

Finally the load flow study is the place that you can really start to save money. Using the results of the load flow study report, you can see where in the system you may have opportunity to increase efficiency. We’ve already written about who can leverage a power system study: engineers aren’t the only group that can use the load flow study in their everyday work.  A couple of examples are how capital projects (power factor correction) and operations (load scheduling) can help your facility save money and pay back the cost of having a study completed in the first place.

Power Factor Correction

By ensuring that the power factor is matched as close to 1 as possible, you system will be operating with the least kW, meaning that you will be paying for the least amount of energy from the utility. The load flow study will determine the best place to install power factor correction capacitors, whether they should be staged or always online.

Load Scheduling

If your facility has a large energy draw, and a lot of motor load, then your power bill will likely be in multiple parts. Each part will have different charges. For example:

  • Energy -kWh
  • Max Demand – kW with a rolling average
  • Power Factor – too much kVAR draw

The load flow study allows you to figure out your baseline operations. You can then start making changes to how new loads are added, and determine the most cost effective way to operate the facility without hurting production.

Conclusion

There are a lot of useful projects that will optimize the operation of your facility: we have only scratched the surface with this article.  If you liked this article, feel free to share it. If you let us know, we’ll add more articles like this one, about utilizing a power system study at your facility to give your business a competitive edge.
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Power System Study Deliverables

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Now that you have decided on the project framework that you are going to go with and you understand the scope of the power system study, you need to prepare the list of deliverables.

Power System Report drafting
Let’s outline the power system study report

There are 3 items that must be included in every report, and there are some things that should NEVER be included in a power system study report body. There are some sources of information that are important to have as backup to both you as the client to evaluate the consultants expertise in the area, and also to educate the non-electrical workers and managers in your company.

Power System Study Deliverables

The 3 overall deliverables that should be included at the end of the project are:

  • Power System Study Report, complete with recommendations
  • Updated drawings with any new information – onelines, switchgear drawings, etc.
  • Power System model in the software of your choice – complete with any custom libraries.

Depending on the scope of the study, you may want to include the following:

  • Capital Budget estimates to implement selected recommendations
  • Updated Electrical Safety Program Documents
    • Typically labels from the incident energy study
    • Updated information for Energized Work Permits

Now lets describe the critical parts of each of these.

Power System Study Report

We outlined the sections that will be included in the report when we discussed scope, but there we only mentioned the specific study results and a section for recommendations.
The report isn’t the place to educate the reader about what the different studies are, the pro and cons of different methodologies, or discussing why it was a good idea to have the study completed. If the report will be distributed to people that don’t have an electrical background and need to be brought up to speed, here’s the tip I use at JMK Engineering:

Include appendices with articles and short whitepaper reports describing what the studies are and how they can be used. This keeps the report on topic, but expands the audience of the complete report.

Introduction

The introduction is the place in the report where the reader is orientated as to what this report is all about. The introduction should include the purpose and scope of the report, the methodology used to gather data and study the system, and standards that were referenced during the work. The sub-headings include:

  • Purpose
  • Scope
  • References
  • Definitions
  • Assumptions and Limitations
  • Project Methodology

Study Analysis Sections

Each study – short circuit, protection coordination, incident energy and load flow – will have their own chapter in the report.  Each of these will have the following sub-sections:

  • Introduction
    • Study specific scope items
    • Study specific source information – utility supply, motor loading assumptions for load flow, system configurations reviewed, etc
    • Thresholds used for warning and critical for the results.
  • Study Results
    • This is only a summary of the results including separate tables for the warning and the critical items.
  • Study Recommendations
    • These recommendations are for the what needs to be done, not the how.  It could be that all the critical lines need to be addressed, but it could be a procedural change (don’t put the system in that configuration)

Appendices

This is where the report starts to grow. The appendices will include the complete analysis outputs for the various studies, including all TCCs for the protection coordination studies. The appendices should also include any pertinent source information that was used in developing the model and report. Here is an example list of appendices that I have included in past reports:

  • Original Proposal (including scope, etc)
  • Data Collection Sheets
  • Relevant Correspondence
    • With the client, utility, suppliers and anyone else that provided useful information that was used in the analysis.
  • Incident Energy Labels
  • What is Short Circuit, Selective Coordination, Incident Energy and Load Flows.
    • This is 4 different articles in one appendix.

Updated Drawings

Next the drawings that are affected by the study and its recommendations need to be updated. What I have found is the drawings lag behind the changes in the field over time, and during the data collection effort we find a number of conflicts, equipment added or removed and settings changed.  The power system study is the perfect opportunity to as-built all these drawings.
The oneline is always caught, but there are other drawings that should be looked at for inconsistencies.  These can include:

  • Threeline diagrams
  • Motor Schematics
  • Switchgear and MCC Drawings
  • Panel Schedules

Power System Model

If you are having an outside resource develop the model, we still recommend you receive a copy of the model and any custom library items electronically. Ideally this will be included on a thumbdrive and included in the report as an appendix.  The best reason for this is that the power system study report is not a static thing, as the system changes it will be updated, and per CSA Z462 and NFPA70E it should be updated no less than every 5 years. After doing all the work – and spending the money – to get the original completed, it is much easier to update with changes than go through the entire process every 5 years.
If the contractor moves along, or doesn’t have good data retention practices, you will lose this data. Get a copy for your records.

Optional Deliverables

The list of deliverables is not exhaustive, and depending on the scope of the power system study you will include others.  Two that I recommend are capital budgets and electrical safety program updates.

Capital Budget Development

You likely have a capital budget cycle that is used to determine what capital projects will be completed in the coming years.  Based on the recommendations outlined  in the report, there are typically additional engineering and installation that will be needed to fulfill the recommendations and make the system safe. To develop these budgets there is some initial engineering design required, but the entire design does not need to be completed in most cases. To present a complete package to management, and allow business decisions to be made, the capital budget report should include the following for each recommendation:

  • Recommendation and why it is needed (Scope)
  • Options – if there are any
  • Capital cost for each option in today’s dollars
    • This should include engineering, procurement, and installation/construction

If there are similar recommendations, like setting changes to relays, these can be grouped.

Electrical Safety Program Updates

If you included an incident energy study in your report, and you have an existing electrical safety program, you will want to make any necessary updates. This may include adding information to the energized work permits, adding new labels and updating the training information

Conclusion

The deliverables related to a power system study are not just labels and an output for the software. To be useful, informative, and actionable we need to include everything mentioned above.  A good consultant will include all the critical deliverables even if you haven’t included them in the RFP, however the lowest price may cut out most of them and provide the bare minimum.
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