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How Harmonic Currents from Inverter Chargers Led to Catastrophic Neutral Overheating at a Municipal Golf Course
This case study examines a catastrophic electrical failure at a municipal golf course following the installation of inverter-type golf cart chargers. Excessive triplen harmonics generated by the new chargers caused severe overheating of the neutral conductor, resulting in a fire and significant property damage. The investigation highlights the critical importance of power quality studies and appropriate system upgrades when integrating modern non-linear loads.
Beyond the headline incident, the narrative follows how a well-intentioned efficiency upgrade quietly changed current waveforms. Replacing legacy chargers with inverter designs introduced peaky, third-harmonic–rich profiles that don’t cancel across phases and instead stack in shared neutrals. The paper explains how charging schedules, feeder layout, and even meter choice can hide the problem until the neutral becomes the hottest conductor on site. Without revealing the full plots, it sketches a monitoring plan—upstream and downstream recorders, neutral-to-phase current ratios, and time-of-use correlation—to surface hazards early.
Key topics include:
- Initial Conditions
- Cart & Charger Replacement Program
- Power Quality Study Findings
- Main Panel Service Drop Neutral
- Incident Analysis and Consequences
Why utilities should care:
Understanding the risks posed by non-linear loads and harmonic currents is essential to prevent infrastructure failures, ensure system reliability, and avoid costly outages or damage when integrating modern equipment such as inverter-based chargers. For utilities and facility owners, the lesson is forward-looking: as cart fleets, e-mobility, and inverter-based loads grow, neutral capacity, wiring practices, and measurement methods must be reassessed. The case offers a decision framework for when to commission a power quality study and what to prioritize, so stakeholders avoid costly, after-the-fact rebuilds. It also helps set realistic expectations for mitigation.
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