How Unbalanced Harmonics from EV Charging Stations Impact Supply and Distribution Equipment

Here, we focus on why power quality matters and what causes harmonics in EVs. We then mention how we went about field evaluation, what field issues we saw, and what mitigation techniques we used.
by Mrs. Nina Sadighi, Eradeh Power Consulting Founder

This case study features insights and observations from field-recorded measurements of unbalanced (per-phase) harmonic distortions at a site with over 300 electric van charging stations. The unbalanced harmonic analysis (UBHA) conducted for the site revealed distortion limits being exceeded for individual phase currents, voltages, and power distribution equipment rating overloads (such as transformer K-rating and cable thermal limits). The presentation also discusses how unbalanced harmonic distortions calculated within the site and at the point of common coupling (PCC) can be mitigated using active or passive harmonic filters and others.

Eradeh Power Consulting is a company that offers design, engineering, and planning services. They provide comprehensive solutions for power systems across a wide range of industries. Eradeh Power Consulting delivers excellence in power engineering by combining time-tested expertise with innovative approaches, ensuring their clients achieve uncompromised reliability, operational efficiency, and sustainable growth. Through rigorous design, data-driven insights, and unwavering quality standards, they transform power infrastructure challenges into opportunities for advancement.

Location: Houston, Texas, USA

Year: 2025

Harmonic Distortion Mitigation in EV Fleet

Challenges

  • Research the causes of harmonics and imbalances in the electrical systems of Electric Vehicle (EV) stations and identify strategies to increase uptime.
  • Evaluate the power quality in EV stations and prepare a comprehensive report considering different scenarios, such as the use of K-rated transformers, passive filters, active filters, or other solutions.
  • Develop an action plan and implement chosen solutions to mitigate harmonics and reduce imbalances.
  • Optimize techniques and costs to achieve and maintain correct operation in the long term focused on compliance with standards.

Which solutions do they choose?

Selected applications

They selected ETAP modeling to analyze electrical charging systems, focusing on harmonic generation and comparing various energy distribution methods.

ETAP ensures compliance with all needed electrical standards for designing and calculating the electrical vehicle station.

Why do they use Etap?

Main Customer Benefits

  • Easy digital modeling of the real grid system, with transformers, busbars, filters, and chargers.
  • Increased energy sawing by 10%.
  • Increased uptime by 20% in the fleet.
  • Reduced electrical equipment damage by reducing harmonic influence.
  • Ability to predict and detect system malfunctions using an accurate digital model.

What do they think about ETAP?

Opinions

Several scenarios were created by using ETAP to perform simulations to determine system responses under various possible operating conditions, including the effects of unbalanced loading and system configurations.
Mrs. Deepika Tummala, Electrical Engineer at ETAP

We brought that [site information] into ETAP model which was I will explain a little bit more. And then from there, we put together a root cause analysis, a comprehensive report that also focused on compliance review and then put developed an action plan, then installed some mitigation solutions and then further evaluated our field results. And what we noticed is that we increased energy savings by 10% and then increased uptime by 20% in the fleet.
by Mrs. Nina Sadighi, Eradeh Power Consulting Founder



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Electrical Power System Analysis