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)

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

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:

1. Short Circuit
2. Protection Coordination
3. 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.

When you sign up we will send you our template power system analysis technical specification that you can include in your next RFP.

Jeff MacKinnon, P.Eng.,PE