Old-school control panels. Photo courtesy of Gene Wolf.

Digital Technology for an Underperforming Grid

June 25, 2024
The power delivery system is one of the most asset-intensive industries in the world.

Have you ever thought of the power grid’s assets in terms of underperforming? It’s not a term that pops up often in relation to utility assets. More likely any discussions about assets are focused on optimization and achieving maximum operational efficiency, but underperforming assets are a reality. This is important because the power delivery system is one of the most asset intensive industries in the world. In addition, there have been numerous studies and reports about the aging components that comprise so much of today’s infrastructure.

Consider a large power transformer (LPTs). It’s one of the most critical components of the power system. One Department of Energy report places the average age of LPTs in the U.S. devices at 40 years, which is at the end of the design life. Adding to the problem is the fact that the manufacturing replacement time for a LPT was around 210 weeks in early 2024 and they appear to be getting longer.

It’s not unusual to find an essential transformer being loaded below its nameplate rating because protecting an indispensable piece of equipment is critical. But it becomes an underperforming asset and that’s why smart transformers have gotten so much attention. At first utilities retrofit their remote LPTs with monitor packages. That allowed them to optimize these critical units’ operation on an as-needed basis. It proved valuable, and today smart transformers come directly from the factory with all the bells and whistles.

Utilities are installing them throughout their systems to be able to respond to voltage fluctuations quickly. They have the capability to assess a smart transformer’s loadings and adjust them to lessen failures and optimize performance. Smart transformer technology communicates real-time field data, which is extremely important for reducing maintenance without increasing outages.

Adding Capacity Without Adding Wire

Another area that needs digital technology for monitoring and controlling its performance is the bulk transmission system. This area has attracted FERC’s (Federal Energy Regulatory Commission) attention with Order 881. It requires all public utilities to implement “Adjusted Ambient Rating” on the transmission lines to monitor and optimize line capacity ahead of the Order’s July 2025 deadline.

DLR (dynamic line rating) technology has been utilized around the world to do that, but its acceptance has been slow in the U.S. Traditionally, transmission lines weren’t designed with optimizing their current-carrying performance in mind. They have been designed using legacy rating charts, which were extremely conservative. This approach has made bulk transmission one of our most underperforming assets on the power grid.

DLR systems use sensors and transducers to measure physical parameters of the transmission line itself as well as weather stations to monitor environmental conditions along the transmission right-of-way. The real-data is fed into sophisticated software and the dynamic ratings for the transmission line are calculated. Reports from utilities using DLR technology say that between 25% to 40% of additional capacity has been added to those existing transmission lines.

Wire Technology

What about utilities that use DLR technology and want more capacity from existing and new additions in planning or design? Well, there have been some remarkable advancements in conductor technologies too. Advanced conductors are taking advantage of modern materials science to increase power flows. Modern technology has produced conductors with improved mechanical performance, power capacity, and improved impedance characteristics.

They are being used for both new construction and reconductoring existing transmission lines. Reconductoring has a lot going for it. It’s much faster permitting wise: existing structures can be utilized with minor reworking, and reconducting with advanced conductors costs about one third of constructing new lines. It’s also estimated that advanced conductors can increase the transmission line’s capacity by 2 to 3 times of the existing conductor it replaces.

A study from the University of California-Berkeley reported that reconductoring the existing transmission lines with advanced conductors could double the capacity on existing rights-of-way and it would only take between 18 and 36 months. Imagine if they also combined this reconductoring with DLR systems. It would be an impressive boost to connecting all the renewable generation stuck in the interconnection queue bottleneck.

Smarter Technology

One of the most asset efficiency improving technologies for the power delivery system has been smart grid technology. It’s taken a lot of research and development to move it from smart electric meters into the rest of the power system, but it’s an integral part today. This cutting-edge technology received a real lift with the tremendous progress made from reducing the physical size of sensors, transducers, actuators, monitoring systems, and such.

Miniaturization made it possible for suppliers to integrate digital technology directly into the electrical equipment and hardware. That evolutionary advancement turned the grid’s transmission, distribution, and substation equipment into state-of-the-art intelligent electronic devices (IEDs), which had an impact on both IT (informational technologies) and OT (operational technologies) applications.

It allowed the sharing of data across the enterprise, and the boundary between IT and OT converged into IT/OT. IT/OT allowed smart grid tools to be developed that focus on improving the performance of individual assets. To date we have only scratched the surface of the possibilities that IT/OT networking can provide, but it’s expanding into high-performance advanced asset managing systems.

These high-performance asset management systems not only keep track of the assets on a utility’s network. When AI (artificial intelligence) was integrated into these schemes, they became able to monitor those assets and provided asset health information along with the ability to predict the failure of any critical assets.

Substation Digitalization

The electrical substation was the next area needing a healthy dose of digital technology to improve its performance levels. The substation has been called the heart of the power

system. It’s the hub where sources and loads are connected, but in the 21st century two-way communications are needed to shorten outages, improve efficiency, and, of course, resiliency.

After the control building was digitalized with its programmable logic controllers, microprocessors, GOOSE messaging, Ethernet process bus, and such, many thought the digital substation was here, but the yard equipment needed to be included. The inclusion of the smart transformer helped, but the addition of IEDs throughout substation yard equipment was the breakthrough that was needed.

Once the IEDs arrived, the process bus was extended to yard equipment using point-to-point fiber-optic cables. Data could now move directly between the outdoor equipment to the indoor protection/control/communications schemes. The control building became a micro-data center that connected every nook and cranny of the substation.

Big-data started pouring from the substation, but it needed to be turned into useful information. That required the high-performance advanced asset management platforms previously mentioned. With AI being integrated into these asset platforms, everything came together with self-awareness and predictive analytics. These recent systems anticipate congestion points, predict equipment failures, and allowing power flow to be controlled in near real-time. That moved the digital substations into the reality column, and has given the digital substation’s enhanced assets the ability to directly interface the physical world with the virtual world.

This is better known as digital twin technology and it has brought connectivity to advanced asset performance platforms, and has taken the digital substation to another level. It made it possible to mesh a series of digital substations together. Data can be compared across the utility’s network, improving efficiency of the power grid. It gives the utility faster response times to external events that could impact their system. Digital substations have turned the traditional substation’s assets into the overachieving performers of the smart grid.

What's Next

There are so many technologies that are critical today when it comes to modernizing the power delivery system. Another category attracting attention is the asset performance improving group known as grid enhancing technologies (GETs). By definition these are technologies that increase capacity, efficiency, and reliability of the transmission grid. According to the DOE, “GETs maximize the transmission of electricity across the existing system through a family of technologies that include sensors, power flow control devices and analytical tools.”

Let’s look at one example of GETs, the power flow controllers (PFCs). PFCs are members of the FACTS (Flexible Alternating Current Transmission System) family. They utilize reactive shunt compensation, series compensation, and phase angle regulation to change the reactance on the transmission line. Basically, PFCs utilize voltage-source converter technology to push and pull power on lines by shifting power flow to maximize the total power delivered on a transmission network. Think of a PFC as a traffic controller that optimizes the existing transmission infrastructure in a meshed network. It relieves overloaded transmission lines while increasing load on underutilized lines in that network. It’s another solution to make an underperforming asset perform more efficiently.

Remember that old axion of the 20th century power grid, “There is no substitute for wire in the air?” Unfortunately, power lines aren’t aesthetically appealing, and they’re expensive and time-consuming to build. We need technological solutions instead. GETs and other technologies may be the solution. Only time will tell!

About the Author

Gene Wolf

Gene Wolf has been designing and building substations and other high technology facilities for over 32 years. He received his BSEE from Wichita State University. He received his MSEE from New Mexico State University. He is a registered professional engineer in the states of California and New Mexico. He started his career as a substation engineer for Kansas Gas and Electric, retired as the Principal Engineer of Stations for Public Service Company of New Mexico recently, and founded Lone Wolf Engineering, LLC an engineering consulting company.  

Gene is widely recognized as a technical leader in the electric power industry. Gene is a fellow of the IEEE. He is the former Chairman of the IEEE PES T&D Committee. He has held the position of the Chairman of the HVDC & FACTS Subcommittee and membership in many T&D working groups. Gene is also active in renewable energy. He sponsored the formation of the “Integration of Renewable Energy into the Transmission & Distribution Grids” subcommittee and the “Intelligent Grid Transmission and Distribution” subcommittee within the Transmission and Distribution committee.

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