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It’s No Cliché, TLM Is a Mess

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Let’s cut to the chase, when it comes to transformer load management, utilities struggle a lot. It’s a double whammy. First utilities never really know when distribution transformers will fail since they are not monitored. Second, they fail at the worst possible times, when demand is at the highest.

Reliability goes down the tubes.

Using ArcGIS and some revised processes, TLM could be a piece of cake. If done right, reliability would soar, and each customer would be happy as a clam. So, let’s get down to brass tacks. What’s the problem?

Many utilities installed their transformers years ago. Planners were caught between a rock and hard place. If they chose transformers to meet the expected connected load, the cost would be prohibitive. if they chose a rating to meet the coincident load, they could run the risk of overloading. Utilities choose the latter.  The jury is still out on that decision. Since utilities don’t monitor the loading of distribution transformers, they are blind as bats as to the times when transformers will be overloaded. It’s impossible to determine the peak load (kW) on a transformer by simply knowing the energy consumption (kW-hr) over a monthly period from each meter connected.

AMI (Advanced Metering Infrastructure) will fix all their problems. Close, but no cigar.  AMI will help if and only if, the utilities have a real-time understanding of which customer is connected to which transformer.

Many utilities haven’t done a great job of modeling their low voltage (secondary) network. They didn’t capture the exact connections of their secondary mains, secondary break points and service connections. Let me spill the beans. Many relied on the dreaded TLM file to document the relationship between customer and transformers. Let’s say a utility added a new transformer in between two old ones. They had to remember to update the transformer to customer file or some variation of that. They often kept that file or table in the customer system or in a separate place altogether.  Often it got way out of date quickly. Utilities also relied on this file for outage management. When I worked for the power company, we would find several customers were either not assigned to a transformer or assigned to a transformer halfway across the service territory.

This problem will get worse. We could end up going to hell in a handbasket. Secondary network systems are under attack more now than ever before. Electric vehicle charging stations are proliferating and will continue to do so. Rooftop solar systems will create over-voltages and harmful harmonics from inverters.

No use crying over spilt milk. No more doom and gloom. Utilities need to bite the bullet and accurately model their low voltage system in ArcGIS. Esri’s new Utility Network technology makes that easy as pie. This makes sense from an asset management perspective anyway. They need the location, the attribution and connectivity of their low voltage system stored in their GIS along with the rest of the network. If they do this, they will discover the customer to transformer relationship automatically.

Dump the TLM file forever.

Integrating AMI with GIS, once the low voltage network is modeled provides a near real-time view of every distribution transformers’ loading. Click on the map. Get the transformer load.  Utilities will be in like Flynn.

This sharpens the focus on distribution transformer asset management. It boosts the utilities ability to link age, overload history, and real time loading with weather patterns. This provides a prescriptive view of their network.

So why did I choose to litter this blog with overused, cliché expressions? For many of these, we have no idea how they came to be. We use them blindly. That’s true also of our work. We often blindly accept processes and practices without really studying how they started in the first place or if they are even valid anymore. Unlocking the underlying reason for practices is often the first step in transformation.  Reforming low voltage network modeling will smooth operations, lower cost and increase customer service.

Well, that’s all she wrote. To learn more about how ArcGIS sharpens customer experience, click here.  

Oh, one more thing. Guess the number of times that Bill used a cliché in his post. Then respond to this blog.  Let’s see how many of you guessed right.  But more importantly, tell what you are doing about TLM.

Bill Meehan's picture

Thank Bill for the Post!

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Matt Chester's picture
Matt Chester on Nov 21, 2019 5:13 pm GMT

So why did I choose to litter this blog with overused, cliché expressions? For many of these, we have no idea how they came to be. We use them blindly. That’s true also of our work. We often blindly accept processes and practices without really studying how they started in the first place or if they are even valid anymore

Bravo Bill-- well executed point and one of the most frustrating parts of working in any industry is getting the answer (whether explicitly said or otherwise) that we do it this way because we've always done it that way.

If I can add another cliche-- they may say "if it ain't broke, don't fix it." But the proper response to that would be: "How are you sure it's not broken? Are you measuring that?"

Pat  Hohl's picture
Pat Hohl on Nov 22, 2019 12:33 am GMT

I enjoyed reading this Bill - very clever and spot on. Finally, a better approach! 


Jim Horstman's picture
Jim Horstman on Nov 27, 2019 3:43 am GMT

Ah Bill, if only it were that easy as apple pie to do. Modeling the secondary network of course is a start but there are a lot of kinks that have to be ironed out in processes to ensure that the model stays correct. One little storm can wreak havoc on that network model. A big one and it's Katie bar the door. Utilizing a design tool that is integrated with the GIS is a start to at least get the model right out the door. But every system that can affect the model and the processes utilizing those systems also need to be integrated in some fashion.

As for the cliches I counted 16 ignoring ones like "near real-time view".

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