The WEC Mandate: Phase Loss Protection for New Medium-Voltage Transformers

If you are planning a new construction project or a major service upgrade within the WEC Energy Group service area—including WE Energies and Wisconsin Public Service (WPS)—there is a critical technical requirement you need to have on your radar.

To ensure equipment safety, the utility now mandates that all new medium-voltage transformer installations include specific provisions for phase loss protection. While existing facilities are currently not required to retroactively update, any new service or material modification must meet these updated standards to be energized.

The Danger of "Phantom Voltage" and Standard Cores

If a phase is lost on the utility (primary) side, the transformer can induce a "phantom" voltage in the dead leg.

This is a "silent killer" for industrial equipment. To basic protection devices, it often looks like power is still present, but your motors will labor under an extreme voltage unbalance. This leads to rapid overheating and catastrophic failure. Because of this risk, WEC Energy Group no longer permits "standard" configurations for new medium-voltage services without a verified protection strategy.

The Two Mandatory Paths to Compliance

At Tech Electric Co., we specialize in helping businesses across the entire WEC service area navigate these two required paths:

1. The Design Solution: Triplex Core Transformers

A Triplex Core transformer is built using three separate single-phase transformers in one tank. Because the magnetic circuits are completely independent, a loss of one phase on the primary results in a clean, total loss on the secondary.

• The Advantage: It physically eliminates the "phantom voltage" issue at the source.

• The Outcome: Your systems detect the fault instantly, satisfying utility mandates with a robust, inherent design.

2. The Detection Solution: Sophisticated Protection Systems

For projects where a standard 3-legged core transformer is utilized, the mandate requires the installation of specialized sensing equipment to catch the phase loss that the core might otherwise mask.

• Our Capability: Tech Electric Co. provides sophisticated solutions for detecting and protecting your system during a phase loss event. We ensure your facility satisfies WE Energies or WPS inspectors while keeping your high-value assets safe.

Lessons from the Field: Avoiding Project Delays

We have seen firsthand the frustration of developers and contractors who were unaware these requirements applied to their new medium-voltage installations until they were deep into the project.

Tech Electric Co. has stepped in on several occasions to adjust project plans before equipment was ordered, helping our partners avoid:

• Costly Change Orders: Preventing last-minute equipment swaps that can derail a budget.

• Inspection Failures: Ensuring your new service passes utility checks the first time.

• Operational Risk: Guaranteeing that your motors and drives are protected from the moment the power is turned on.

  
  

Your Partner for Wisconsin Utility Compliance

Whether you are breaking ground on a new facility or managing a significant power upgrade, the responsibility for phase loss protection for new services sits squarely with the customer.

• Deep Technical Knowledge: We understand the nuances of transformer design and the latest WEC Energy Group Service Rules.

• WEC Service Area Expertise: We stay current on the specific mandates for both WE Energies and WPS.

• Tailored Options: From Triplex Core designs to advanced detection solutions, we provide the best options to meet the mandate.

  
  

Planning a New Medium-Voltage Project?

Don't wait for the utility to flag your designs at the eleventh hour. Contact Tech Electric Co. today for a technical consultation to ensure your new transformer installation is safe, compliant, and ready for service.