If your electrical system were a car, a power system study would be the full diagnostic, not the oil change. It looks at how the entire system behaves under normal loads and during faults, then tells you whether your equipment and protective devices are up to the job.
Many facility managers hear the term for the first time when an insurer, an inspector, or a contractor asks for one. This guide explains what a power system study is, the different types, and what you should expect to receive.
What Is a Power System Study?
A power system study is an engineering analysis of a facility’s electrical distribution system. Engineers build a computer model of the system, from the utility service down through transformers, switchgear, panels, and major loads, then run calculations to evaluate fault levels, device coordination, load flow, and arc flash hazards. The results show where the system is safe and adequate, and where it needs changes.
It’s really a family of studies rather than a single one. Most facilities need several, and they build on each other.
The Main Types of Power System Studies
Short circuit study. Calculates the maximum fault current available at each point in the system. The key question is whether your breakers, fuses, and equipment are rated to safely interrupt or withstand that current. Underrated equipment can fail violently during a fault.
Protective device coordination study. Confirms that when a fault happens, the device closest to it trips first, rather than a main breaker upstream taking down a whole building. Good coordination keeps a small problem small.
Arc flash study. Uses short-circuit and device clearing time data to calculate incident energy at each piece of equipment. The results set arc flash boundaries, PPE requirements, and equipment labels. Shaw’s arc flash assessment service covers this study type in depth.
Load flow analysis. Shows how power moves through the system under normal operating conditions, including voltage levels, feeder loading, and transformer capacity. It’s essential before adding major loads or reconfiguring equipment.
Harmonic analysis. Evaluates distortion caused by variable frequency drives, LED lighting, UPS systems, and other electronic loads. Harmonics can overheat transformers and neutrals and cause equipment to misbehave.
Motor starting study. Checks whether large motors can start without causing voltage dips that disrupt other equipment.
How a Power System Study Works
- Data collection. Field technicians gather nameplate data from transformers, breakers, fuses, cables, and major equipment, and the utility provides available fault current at the service. This step is the foundation of everything that follows, and it’s where incomplete or inaccurate data causes the most problems.
- One-line diagram and modeling. Engineers create or update the single-line diagram and build a software model that mirrors the real system.
- Analysis. The model runs the required calculations: fault currents, device performance, coordination curves, incident energy, and load conditions.
- Recommendations and reporting. Engineers identify issues and propose fixes, such as adjusting breaker settings, replacing underrated equipment, or reducing arc flash hazards.
What Your Facility Gets From a Power System Study
A good study produces more than a thick report that sits on a shelf. You should receive:
- An updated single-line diagram that reflects your system as it exists today
- A system model that can be updated later instead of rebuilt from scratch
- Equipment evaluation results showing any devices rated below available fault current
- Recommended protective device settings that improve coordination
- Arc flash labels for each piece of equipment, if an arc flash study is included
- A prioritized list of corrective actions so you know what to fix first
These deliverables support safety compliance, maintenance planning, and future projects. They also give contractors and engineers accurate information the next time you expand or renovate. For a closer look at the operational payoff, see how power system studies improve electrical reliability and efficiency.
When Should You Commission a Power System Study?
- During design of new construction or major renovations
- After significant changes such as new transformers, generators, or large loads
- When the utility changes your service or available fault current
- At least every five years, when NFPA 70E requires arc flash risk assessments to be reviewed
- When you experience repeated nuisance tripping or unexplained equipment failures
How Shaw Consulting Services Helps
The accuracy of any study depends on the quality of the field data behind it. Shaw Consulting Services was built around that idea. Our cloud-driven process connects field personnel and engineers in real time, so questions get answered while the team is still on site, not weeks later. Working from our Atlanta headquarters on Cumberland Parkway, we deliver power system studies for commercial and industrial facilities across Georgia and nationwide, with models you can keep updating as your facility grows.
Frequently Asked Questions
What is the purpose of a power system study?
It confirms that your electrical system and equipment can safely handle normal loads and fault conditions, and it identifies changes needed to improve safety, reliability, and compliance.
How long does a power system study take?
It depends on facility size and data availability. Smaller facilities may take a few weeks from data collection to final report, while large industrial sites can take longer.
Is a power system study the same as an arc flash study?
No. An arc flash study is one type of power system study, and it depends on the results of the short-circuit and coordination studies.
Do I need to shut down my facility for data collection?
Usually not. Most data can be gathered from equipment nameplates and existing documentation, though some equipment may require opening panels under proper safety procedures.
How often should a power system study be updated?
Whenever significant system changes occur, and at least every five years for arc flash review under NFPA 70E.