“Modern grids will not fail because electricity stopped moving. They will fail because electricity started moving faster than our instruments, rules, and assumptions could understand.” – MJ Martin
Introduction
The modern power grid is being asked to do something it was never originally designed to do: serve massive digital loads that can change faster than traditional planning, metering, protection, and market systems can interpret. A recent LinkedIn post by Mica Tufillaro of LIS Analytics framed this problem sharply, arguing that the North American grid is moving from a slow planning problem into a real-time physics problem. The concern is not only whether the grid has enough megawatts. The deeper issue is whether the grid can remain stable when large electronic loads create distortion, oscillation, and rapid demand changes inside timeframes measured in seconds, cycles, or milliseconds.
3rd order harmonics belong directly inside this discussion. A 3rd harmonic is a frequency component at three times the fundamental system frequency. In North America, where the grid operates at 60 hertz, the 3rd harmonic occurs at 180 hertz. It is not simply background electrical noise. It is a measurable waveform distortion that can overheat neutral conductors, stress transformers, distort voltage, interfere with sensitive equipment, and expose the limits of old assumptions about balanced three-phase power.
The Grid Is Moving Faster Than the Models
The North American Electric Reliability Corporation has now elevated large computational loads into a reliability issue. NERC released a Level 3 Essential Action Alert on large load challenges in May 2026, focused on computational load modelling, studies, instrumentation, commissioning, operations, protection, and control. NERC’s Large Loads Action Plan also identifies artificial intelligence data centres, cryptocurrency mining, industrial facilities, and hydrogen production as emerging load categories that require new reliability attention. (NERC)
This matters because much of the grid’s administrative machinery still thinks in minutes, hours, months, and planning years. Market settlements, balancing intervals, and load forecasts are often built around averaged data. But physical electricity does not wait for the next interval. When a large digital load trips, ramps, or oscillates, the wire responds immediately. Voltage, frequency, phase angle, neutral current, harmonic content, and transformer heating all move according to physics, not paperwork.
Why 3rd Harmonics Are Different
A harmonic is an unwanted frequency component riding on top of the normal power waveform. Linear loads draw current in a smooth pattern that follows the voltage waveform. Non-linear loads do not. They draw current in pulses, often because electronic power supplies, rectifiers, inverters, and switching devices convert AC power into DC power and then back into controlled forms of energy.
The 3rd harmonic is especially important because it is part of the triplen harmonic family, which includes the 3rd, 9th, 15th, and 21st harmonics. In three-phase systems, triplen harmonics are zero-sequence components. That means they are in phase with each other across all three phases. Unlike fundamental current, which largely cancels in the neutral conductor when the system is balanced, 3rd harmonic current adds in the neutral.
This is the hidden danger. A facility may look balanced when viewed through conventional phase current measurements or 15-minute interval data. Yet the neutral conductor may be carrying a large accumulated harmonic current. The average demand can look acceptable while the electrical system is quietly heating, ageing, and moving closer to failure.
The Neutral Conductor and Transformer Problem
Neutral conductor overloading is one of the classic symptoms of 3rd harmonic distortion. Older design assumptions often treated the neutral as a conductor that carried only imbalance current. In a modern building filled with computers, servers, LED lighting, EV chargers, power supplies, variable frequency drives, and control electronics, that assumption can be wrong.
When 3rd harmonic currents from each phase return together through the neutral, the neutral may carry more current than expected. This can damage insulation, loosen terminations, raise fire risk, and create unstable line-to-neutral voltages. The issue is especially relevant in commercial buildings, data centres, hospitals, schools, municipal facilities, and industrial sites with dense electronic loads.
Transformers face a related problem. Harmonic currents increase heating through eddy current losses and stray losses. A transformer may appear to be operating within its apparent capacity while still running hotter than expected because the waveform is distorted. Over time, heat shortens insulation life and reduces asset reliability. In this sense, harmonics are not just a power quality inconvenience. They are an asset management problem.
Canada Is Not Insulated from the Risk
This issue does not stop at the Canada and United States border. Canada does not operate as one isolated national power grid. Its provincial systems are often connected more strongly north to south with the United States than east to west with other Canadian provinces. The Canada Energy Regulator states that large-capacity electricity transmission infrastructure has been built predominantly between Canada and the United States, not between provinces and territories. It identifies major connections from British Columbia to the U.S. Pacific Northwest, Manitoba to the U.S. midcontinent, Ontario to U.S. midcontinent and eastern grids, Quebec to the U.S. eastern grid, and New Brunswick to New England. Alberta and Saskatchewan also have links to Montana and North Dakota. (Canada Energy Regulator)
The grid does not recognize political boundaries. It responds to impedance, frequency, voltage, inertia, protection settings, and load behaviour. If a large computational load in the United States creates a sudden disturbance, the effects can propagate through interconnected systems. If a similar load in Canada behaves poorly, it can also affect neighbouring U.S. systems. Cross-border interconnection improves reliability and trade under normal conditions, but it also means reliability risk is shared.
The 2003 blackout remains the clearest warning. IESO states that more than 50 million people in Ontario and the northeastern United States were affected on August 14, 2003. The event involved large power swings ranging from 2,000 to 4,000 megawatts through New York, Ontario, and Michigan, and roughly 61,800 megawatts of customer load was interrupted. (IESO) That blackout was not caused by AI loads or 3rd harmonics, but it proved the larger principle. A disturbance in one part of the interconnected grid can cascade across borders.
Why This Matters for Canadian Utilities
For Canadian utilities, 3rd harmonics and sub-cycle instability should be treated as early warning signals of a more electronic grid. Canada is pursuing electrification, electric transportation, data centre growth, mining electrification, industrial decarbonization, battery storage, and distributed energy resources. These loads and resources bring benefits, but they also introduce faster controls, power electronics, inverter behaviour, and waveform distortion.
A Canadian utility cannot manage this future with monthly billing data alone. Even 15-minute interval data may be too slow to reveal the real problem. Utilities need power quality monitoring, harmonic analysis, waveform capture, neutral current measurement, transformer thermal modelling, and better visibility at the Point of Common Coupling. The Point of Common Coupling is where the customer’s electrical system and the utility grid meet. For large electronic loads, it is the essential diagnostic boundary.
This is also a sovereignty issue. Canada benefits from deep grid integration with the United States, but that integration means Canada shares exposure to American load growth, American reliability events, and American market stress. At the same time, U.S. regions depend on Canadian electricity exports and grid support. The relationship is valuable, but it requires disciplined technical coordination.
Summary
3rd order harmonics are not an isolated electrical nuisance. They are a symptom of a grid being reshaped by electronic loads, fast controls, and digital infrastructure. They reveal what old averages can hide: overloaded neutrals, stressed transformers, distorted voltage, and equipment operating in conditions that conventional reports may miss.
NERC’s large-load warning confirms that the issue is no longer theoretical. The grid is becoming faster, more digital, and less forgiving. For Canada, the stakes are amplified by deep interconnection with U.S. power systems. Canadian utilities and large-load customers must see the waveform, not just the meter reading. The future grid will require capacity, but it will also require clean power, fast observability, stronger local mitigation, and a much better understanding of what is happening at the wire.
About the Author:
Michael Martin is the Vice President of Technology with Metercor Inc., a Smart Meter, IoT, and Smart City systems integrator based in Canada. He has more than 40 years of experience in systems design for applications that use broadband networks, optical fibre, wireless, and digital communications technologies. He is a business and technology consultant. He was a senior executive consultant for 15 years with IBM, where he worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin served on the Board of Directors for TeraGo Inc (TGO: TSX) and on the Board of Directors for Avante Logixx Inc. (XX: TSX.V). He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology. He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now Ontario Tech University] and on the Board of Advisers of five different Colleges in Ontario – Centennial College, Humber College, George Brown College, Durham College, Ryerson Polytechnic University [now Toronto Metropolitan University]. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees – in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and seven major certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has completed over 80 next generation MOOC (Massive Open Online Courses) [aka Micro Learning] continuous education programs in a wide variety of topics, including: Economics, Python Programming, Internet of Things, Cloud, Artificial Intelligence and Cognitive systems, Blockchain, Agile, Power BI, Big Data, Design Thinking, Security, Indigenous Canada awareness, and more.
Martin in a volunteer, a photographer, a learner, a technologist, a philosophizer, and a romantic optimist.