Power Systems Analysis

Executing a Power System Study at a pulp and paper mill

Jeff MacKinnon, P.Eng · Jun 7, 2016 · Leave a Comment

There are a lot of different ways to successfully complete any power system study, but the best for any pulp and paper mill is likely a hybrid, with a lot of the time consuming activities being down with mill staff. The advantage of this system, is that when you have the scope of the project outlined, you can start gathering the necessary information before engaging a consultant.
Here are three thoughts around data gathering (the most costly part of a power system analysis) when you decide to get started with a power system analysis project at your pulp and paper mill.

Data Gathering

Typically the most time consuming part of developing a complete power system model is data gathering. This is something that is best done by the people that know the facility the best, and have the best grasp on the electrical safety program. A lot contractors will want to bring in outside help, but if the system is under operation this will increase the risk of an unscheduled shutdown as these inexperienced contractors are rooting around in MCC buckets trying to find wire sizes.

1. Start off with drawings

Most of the information needed for a power system analysis, especially the short circuit study, can be found in the existing drawings:

single line diagrams
motor elementaries
General Arrangements (cable lengths)

If you couple this with other support documentation like cable lists and relay setting sheets, the biggest chunk of the information will be done. However, this doesn’t mean you don’t have to get out into the field and verify everything. Unfortunately, drawings and support documentation don’t have all the current information, some examples that may be missing are:

fuse manufacturer
transformer impedance
cable length

These will need to be as-built in the field during the data gathering process, and recorded. As one of the deliverables, the affected drawings will be updated when the report is completed.

2. Ideally completed by the owner’s staff

Based on the age and complexity of most forest product plants, we recommend that plant staff (preferably electrical workers) gather the information over a reasonable period of time. Electrical shop workers are routinely all over the mill, and adding a requirement to as-built information as a routine task will limit the back work, and is a good habit to be in for any case.

Accurate drawings shorten unplanned shutdown times.

One of the side benefits of having current drawings is when something does go wrong, you can troubleshoot from a drawing, and then implement solutions. If you are always worried the drawing is incorrect you ended up drawing out the circuit on a napkin (or any other scrap of paper) while you troubleshoot, all the while 5-10 people are looking over your shoulder “helping”.

3. Best done during shutdowns

Speaking of shutdowns, opening up switchgear and MCC buckets is best down during planned shutdowns. Partial shutdowns are a normal part of a pulp and paper mill, by ensuring there are enough electrical workers on staff during the outage to support the data gathering effort.
It is important to gather the data in a safe manner, ideally with the equipment de-energized. A shutdown allows you to access a large majority of the equipment de-energized, without affecting the rest of the plant process. While inspecting may not be a “working on” type task based on your energize work permit, finding some of the information may require manipulating wires, etc. For example, how often do you think you will see the wire gauge in a MCC bucket?

Next Steps

A power system analysis report is a critical tool for any pulp and paper mill in today’s lean wood products economy. If you are interested in learning more about power systems you can join our Power System Newsletter here, when you do we will send you a technical spec that you can use with your next RFP.
If you have any questions give me a call or send me an email, you can find my contact information here. If you liked what you read, signup for our newsletter below.

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

Jeff MacKinnon · May 31, 2016 · Leave a Comment

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

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.
One 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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Getting a Cement Plant Power System Report Completed

Jeff MacKinnon, P.Eng · May 24, 2016 · Leave a Comment

Over the last couple of weeks I’ve talked about the steps to get a power system analysis completed, and the different execution strategies. Today I want to talk specifically about cement plants.
Cement plants have a cyclical profile where they are producing product before the building cycle, and full out throughout the building cycle (spring to winter) to keep with demand, then annual maintenance in the winter until it is time to get started again.

Hybrid Approach

With leaner engineering groups in all of industry, we recommend a hybrid approach with you using internal electrician and engineering resources to gather the data needed for the complete power system analysis. If there aren’t any power quality concerns at the plant, or your power system study isn’t current we recommend getting started with:

Short Circuit,
Protection Coordination, and
Incident Energy (Arc Flash)

Recommended Scope of the Power System Analysis

The cement plant power system is large and complex, with a range of voltage levels from 100kV to 120/208V. If you are starting from scratch at the plant, or if you (or the person running the project) don’t have a lot of experience with power system studies, it is best to chunk out the system in bit sized chunks. But make sure that how you break out the system is done in such a way that you will have a useable product at each stage.

How much of the Cement Plant Power System

For example, we recommend that you model the entire MV system, from the incomming from the utility down to any 5kV that is on the plant. This will allow you to address all the large motors, generation and utilities on the site that will account for the majority of the fault availability. Depending on the size of the system and budget, this may be all that you get done in the first round.
The next step is to pick one of the feeders in your system, or a single area of the plant and complete the model (and report) to the 600 V (or 480V in the US) system and include all motors 25hp and over, and to the secondary of any 120/208 distribution panels. Motors less than 25hp will likely not affect the available back feed into a fault, and therefore can be neglected.

120/208V system

The 120/208V distribution panels may be contentious and not needed at your facility. I have typically neglected them in the past, however there are still a lot of electricians that will work on a panel at this voltage energized without a second thought, I have started recommending labeling these panels with full Arc Flash/Shock Warning labels with the intent of raising the awareness that the hazard is still present, and PPE is required.

Electrical Safety Program

In the 2015 revision of NFPA 70E mining was removed from the exceptions, and MSHA has endorsed NFPA 70E as the standard for PPE selection with regards to arc flash. What this means to you is that NFPA 70E is the de-facto workplace electrical safety standard for cement plants.
Having a current (every 5 years) arc flash analysis, which includes a power system study, is a requirement for any successful electrical safety program.

Getting Started today

If you aren’t in a position to get started with a power system analysis at your cement plant today, sign up for our power system newsletter and you will receive a technical spec that you can use to get pricing when you are ready to get started.
If you are ready, to go NOW, give us a call and we can provide a free quote and execution plan to ensure that the report meets all operational needs of your engineering and safety groups.
As always, if you have any comments or questions, don’t hesitate to give me a call.
Regards,
JM

3 Ways to get a Power System Analysis Completed

Jeff MacKinnon · May 17, 2016 · Leave a Comment

You already know why you need a power system analysis at your plant, but what about actually executing the project. There a three basic way to approach getting a power system analysis completed:

Completely In-House
Completely contracted out
Hybrid of both

These have their pros and cons, and depending on the size and complexity of your company and system the method that is chosen may be obvious. Below is a brief description of each method, including a couple pros and cons of each.

1. In-House

When you complete the power system analysis in-house, you will have the advantage of being in complete control of the end study, and as a company you will have a better understanding of the status of the power system as a hole. This is one of the less talked about advantages of having a power system analysis prepared, it gives you the opportunity to double check all your drawings and understand any oddities throughout.
Completing the power system analysis in-house assumes you have the resources within your team, including

Skills – Someone has done these before and knows how to do this one
Tools – The necessary software is in-house and there are staff trained in using it.
Time – There are resources to complete all five steps to get it done.

2. Outsourcing

When you outsource the power system analysis to your favorite consultant, it can be a simple matter of writing up a scope and walking away.

If you need to have multiple companies bid, I would recommend adding our free technical spec, get it when you sign up for our Power System newsletter.

This will greatly reduce the drain on internal resources, now you only need to monitor a contract and review the reports. However, when you do this you also lose some control and add to the monetary cost of the project greatly.
In summary, outsourcing the project will likely reduce you direct input greatly, while increasing the project cost.

3. Hybrid Model

A hybrid model is one that keeps your involvement high, while outsourcing the project parts that you don’t have the resources to complete, whether its time or skills. For example, assume that your company has the resources to gather all the data for the project, but doesn’t have the necessary software or anyone available that has experience in preparing a power system analysis. In this case you could outsource the model development, studies and report (steps 3-5) and prepare the scope and gather the data using company resources (steps 1 and 2).

Hybrid micro grids are the future — Hybrid power systems are the future

This model has the advantage of ensuring that the data used in the analysis is accurate to site conditions as your personnel will know the site better than anyone, the cost will be kept under control as data gathering is one of the most tedious and expensive parts of the project when completed by an outside resource, and the study results and recommendations will be accurate and actionable because you had an experienced consultant prepare them for you.
The hybrid model allows the power system analysis project execution to be:

Good input data – know one knows the facility better than the people who operate it day in and out
Cost Effective – consultants doing what they do best, and company resources gather the necessary data
Accurate and Actionable – experienced consultants who have the tools, and training can provide the best report.

What we think

In most cases we will always recommend some type of hybrid model, but the split will always be different and dependent on the resources of the company that we have engaged with to complete the analysis. By using a hybrid model you will be able to leverage our strengths in power system modelling and analysis to produce a great product, while using your internal resources to gather the necessary input data to keep the costs low (and value high) without sacrificing quality.
If you have a project that you want to talk to us about don’t hesitate to use the contact page, or send us a note using the form below. You will be signed up for our power system newsletter and we will get right back to you.

5 Steps to Complete a Power System Analysis

Jeff MacKinnon · May 10, 2016 · Leave a Comment

If you have never been involved in a power system analysis before, it may seen like a very daunting task. To help add some structure to this here are the steps involved with getting one completed, and a description of each.

Determine the scope of the Power System Analysis
Gather the data
Create the Power System Model
Run the necessary Power System Studies
Write the Power System Analysis Report

1. What is the Scope?

Before I start any power system analysis project, or even start to price the project, I help work out the detailed scope needed for the report. This mostly has to do with, why is the power system analysis needed? The reason that it is needed will determine the specific studies that will be run, and therefore the data that will be needed in the second step. A couple of examples of this are:

Input to the Electrical Safety program (Arc Flash Labels)
Future Capital Expansion
Power Quality Concerns

2. Getting the input information

With regards to usefulness, getting the necessary input information for a power system analysis is the critical step. With bad, or incomplete, information, the model and the resultant studies are not going to be accurate. If the purpose of the power system analysis is to develop labels as part of an electrical safety program, this means that PPE will be selected based on the outputs of the analysis, being wrong will put electrical workers at a higher risk than they expect.

Garbage in, garbage out.

Gathering the information is typically both the hardest and most time consuming part of a power system analysis. It requires combing through existing drawings, and then verifying that this information matches the installed conditions. Some of the information that is required for an arc flash analysis are:

Nameplate information of:
- transformers
- motors
Circuit breaker settings
Fuse settings
Cable and Raceway information
- conductor size and configuration
- conductor length
- raceway material (ferrous or non-ferrous)

Electical control panel at an oil production plant — Sometimes you will have to go right to the source

A lot of this information can only be verified behind the enclosure doors, and since this hypothetical scenario is for an arc flash anaylsis, there is no recommended PPE, therefore it must be completed de-energized. For a lot of facilities, this requires coordination with already busy shutdowns, etc. Planning is the key to any successful power system analysis

3. Putting the Data Together

The next step along the journey to a completed power system analysis is putting all the data that was gatherd in the previous step into a power system model using the software of choice, my preference is ETAP, but there are other great options out there.
Creating the power system model is mostly data entry, and is pretty straightforward, but care is taken to ensure that all the data is correct so that the resulting studies are not misleading.

4. Running of the Power System Analysis Studies

Which studies are necessary will depend greatly on the scope of the project that was figured out in Step 1 above. In Power System Analysis in Industry I talked about the 3 that I always recommend:

Short Circuit
Protection Coordination
Incident Energy (Arc Flash)

These studies allow you to prepare updated labels for your equipment, determine if there are any existing equipment that needs to be replaced on short circuit duty, and ensure that the protection coordination of your plant is adequate for your operations.

5. Writing the Power System Analysis Report

Finally comes the report. With all the information above, the report will summarize the results of the studies and provide any recommendations. The report is the most important power system analysis deliverable. With a detailed report, you will be able to create action items for any of the issues that were discovered, and have a great base point to build and improve the quality and reliability of the power system at your plant.

Closing

I help clients of all industries and situations through all these steps. We have started preparing a detailed checklist based on these 5 important steps. If you are interested in getting a copy when its done fill out the form below, or here. When you sign up we will send you our template power system analysis technical specification that you can include in your next RFP.
As always please don’t hesitate to contact us if you have any questions!
Cheers,
Jeff MacKinnon, P.Eng.,PE