Go with the flow: The Importance of Load Flow Studies

Monday, September 17th, 2012

If you’re running an industrial power system—whether for an airport, a mill, a factory or a smelter—you’re focused on more than the traditional utility concept of keeping the lights on. You definitely need that power to be available, no doubt, but what you’d really like to know about are the details: quality, flow, consistency—items that impact your machinery, your schedule, your production and, often, your bottom line.

This issue, let’s chat about the one area easiest to analyze: load flow. It’s one of the most important items on the maintenance schedule and, it’s true, that load flow discussions in the power industry may be on overload at this point. But, it’s talked about so often because it’s vitally important.

What does studying the load flow do for you? It helps you ensure that your power is connecting in the best ways, that it’s stable for delicate equipment, that it’s reliable for a production line, and that it’s working to your utmost advantage.

Sometimes called a “power flow” study as well as the traditional “load flow” label, it’s all about putting numbers and stats to work on your maintenance plan. It simplifies complex equipment—sometimes down to a one-line diagram—and looks in at all the nooks and crannies, including voltage and reactive power. (The good news is: This can be outsourced to AVO Electrical Engineering Division. You don’t have to have a numbers-and-power genius on staff for this study.)

What does a load flow calculate, specifically? Voltage drop on feeders, voltage at each bus and the power flow and losses in all branch and feeder circuits. Load flow studies determine if system voltages remain within specified limits under normal or emergency operating conditions and whether equipment (such as transformers and conductors) is overloaded.


The right look inside your power system gives you what’s known as a “base case,” or the basics to work from to run smoothly and efficiently. In fact, the Holy Grail to aim for with a load flow study remains optimization: How do you get the most bang per cheapest kWh? A good flow study can also help prevent downtime and, by extension, cost and product loss. (You can also build on this base case with more detailed analysis as needed.)

How can you use a load flow study beyond a simple base case? Optimization is the beginning, of course. Additionally, you can get some nice, practical profiles of bus voltage. You can identify real and reactive power flow and minimize kW and kVar losses. Additionally, the load flow study can help identify proper transformer tap settings and, finally, give you an idea on guidelines for equipment.

And, load flow studies become especially important when looking to grow and expand your business—and put more load on your power infrastructure.

But, that voltage profile that load flow gives you will be your most practical tool. That can help you prevent large and problematic reactive flow, power loss or voltage collapse. With power, there’s great quality in consistency. And a load flow study helps you keep that consistency happily, mundanely consistent.

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