Tackling the energy transition with a grid that can sense, think, and act
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Why do renewables such as distributed energy resources (DERs) present such a challenge? The hard truth is that the majority of electric grids were not originally designed to accommodate DERs, writes Dominique Verhulst, head of the Energy Segment at Nokia’s Network Infrastructure Group.
When world leaders agreed at the Conference of the Parties 28 (COP28) in Dubai, held in December 2023, to transition away from fossil fuels, anyone operating a power grid surely took notice. While expanding renewable energy capacity is good news for the planet, it’s bittersweet for utilities who – according to a special report by the International Energy Agency (IEA) – are already at risk of becoming a bottleneck in the global shift toward renewables.
All this ratchets up the importance of transforming the power grid into a dynamic entity that can sense, think, and act. Not an easy feat – but a necessary one for a power grid that has been mostly static since its birth in the 1880s.
Why do renewables such as distributed energy resources (DERs) present such a challenge? The hard truth is that the majority of electric grids were not originally designed to accommodate DERs.
DER for Reliability is an educational track at DISTRIBUTECH International,
set for Orlando, Florida February 26-29, 2024.
Obstacles will emerge when balancing energy supply and demand, coupled with managing fluctuations in voltage and frequency. Moreover, many renewable sources rely on unpredictable weather patterns, presenting a challenge for a grid that requires continuous, intensive oversight of DER infeed conditions at the interconnection point to maintain electricity balancing and help ensure stability and safety. Additionally, the proliferation in micro/nano grids and bi-directional electricity flows from “prosumers” that must be integrated into the grid.
Thus, to adapt to the clean energy future, the power grid must be able to sense, think, and act. And what does it mean for the power grid to sense, think and act?
For starters, it must sense, as in measure and monitor, which of the many DER inputs it is dealing with. Then it must think about how to adapt to the ever-changing landscape of energy supply and demand.
Indeed, think at a level that – given the extensive scale and high-density presence of DERs on the grid – demands help from grid applications that embrace new technologies like artificial intelligence to evaluate how best to generate and dispatch power to meet the load demands. Then it must act through intelligent electronic devices (IEDs), which again – as the power grid scales in size and complexity – will require technological assistance to act in a synchronized and coordinated manner.
Let’s take a look at the role of a converged field area network (FAN) and how it helps transform the power grid into an entity that can sense, think, and act as more and more megawatts of renewables enter the system.
Introducing field area networks
Converged FANs help utilities extend communications deep into the distribution grid to enable integration of DERs as well as storage, distribution automation, substation automation, and advanced metering infrastructure.
Converged FANs connect IEDs in substations and on feeder circuits that sense line conditions. Grid management systems and automated controllers across the grid apply application logic to think and send commands to IEDs to act, essentially to protect and control the grid.
A converged FAN integrates an IP/MPLS field router with a private LTE network, bringing resilient and secure broadband network services to the distribution system. This enables system operators to wirelessly deliver a broad range of distribution automation applications to utility poles, low-voltage substations, and DER sites, connecting IEDs (such as reclosers and line switches), CCTV, drones, and other devices.
Addressing islanding
Islanding prevention is a good example of why FANs are becoming more crucial to power grid operations. For example, as line sensors across feeder circuits send current measurements from a feeder circuit to a recloser controller, the controller logic will analyze the data in real-time to detect fault currents. Once detected, it will command reclosers adjacent to the fault location to open.
When the circuit connects with a community solar project rather than a traditional one-way grid, further remedial action is required.
Should the solar array inverter fail to detect island formation, it would still continue to supply power through the point of common coupling (PCC) into the section of the feeder circuit downstream from the recloser. This situation results in an islanding condition, posing a hazard to the dispatched crews addressing the fault as well as to the local electrical equipment on that particular section of the feeder.
With a converged FAN, control logic gains the capability to issue a trip command to the downstream switch at the PCC, preventing the DER from energizing the feeder.
Restoring service
Another key to improving grid reliability is through fault location, isolation, and service restoration (FLISR), which brings self-healing capabilities to power grids.
According to a U.S. Department of Energy study, FLISR can have the potential to decrease customer minutes of interruption (CMI) by 53% and the number of customers interrupted (CI) by 55%. That’s because a line sensor can send a message to the FLISR controller to indicate a service interruption which kicks off a process whereby power is re-routed, and users are reconnected to a different substation.
This is not a bandwidth-intensive process. Add DERs to the power grid, though, and things get complicated.
When a DER contributes to a fault, there are many locations to isolate, surpassing the capacity that older FLISR systems can manage. The key is to make the advanced distribution management systems (ADMS) aware of the exact configuration of circuit topology and model the more complex system in the ADMS software so that it can correctly carry out the restorative actions through dynamic circuit reconfiguration.
Centralized ADMS FLISR applications demand substantial flexibility to manage multi-way communications with IEDs in the substation and on feeder circuits. This is necessary to collect data and send instructions once the fault(s) are located and appropriate actions are determined.
In some FLISR implementations, the application logic is run in the substation with IEDs that also communicate with each other for heightened awareness. A converged FAN has the ability to support, flexible any-to-any communications in order to meet this complex need.
Mitigating fire risk
FAN is crucial in supporting applications that monitor for and s iftly detect falling power lines, a factor implicated in some of the most severe forest fires of this century.
Identifying and de-energizing falling conductors before they reach the ground is essential for mitigating wildfires. A converged FAN, leveraging IP/MPLS and private LTE/5G, can also carry real-time synchrophasor data for the distribution automation controller to detect and de-energize falling power lines. In fewer than two seconds, a falling line can be detected and isolated while in mid-air – before it sparks on the ground – significantly mitigating the threat of widespread destruction and injury or death.
Dynamic energy grids
Certain attributes are required for a converged FAN to support grid communications and empower the grid to sense, think, and act. Look for a solution with end-to-end multi-fault network resiliency, deterministic quality of service for assured data delivery, any-to-any multi-point connectivity for more efficient machine-to-machine communications, and robust cyber security defenses.
As power grids integrate more DERs, the converged FAN will play a significant role in guaranteeing effective energy provision and administration – thereby removing the risk of power utilities becoming the bottleneck in the world’s sustainability efforts. A dynamic energy grid that can sense, think, and act is the foundation for the power grid of the future.
About the author
Dominique Verhulst currently heads the Energy Segment at Nokia’s Network Infrastructure Group.
Leveraging Nokia’s portfolio of Fixed, IP&Optical, and professional services products, Dominique drives the business and solutions development for Energy customers globally. He is the author of the “Teleprotection over Packet Networks” e-book available on the iTunes bookstore, and co-author of several publications from the University of Strathclyde on the matter of Differential Protection over IP/MPLS. He has over 30 years of experience in the telecommunications networking industry, holding senior sales and marketing positions at Nokia, Alcatel-Lucent, Newbridge Networks, Ungermann-Bass and Motorola.
