Hydro One
Solving Voltage Mismatch for a Major Utility

Industry: Electric Utility — Testing and Maintenance Operations

Location: Ontario (Canada)

Challenge: Several bench test workstation required 120V nominal for test equipment, but the available supply at the workstation was approximately 100V nominal, creating an undervoltage condition that could disrupt reliable testing.

Solution: We supplied buck/boost transformers configured for fixed voltage correction to boost approximately 100V nominal toward 120V nominal at the point of use.

The Challenge: Voltage Correction for Critical Test Work at a Major Utility

Hydro One is a major electric utility in Ontario, Canada with operational standards that demand reliable, repeatable test and maintenance work. At the Thunder Bay facility, multiple bench test workstations needed to power equipment designed around 120V nominal utilization voltage.

The issue was a localized voltage mismatch: the available supply at the workstations was approximately 100V nominal, while the test equipment required approximately 120V nominal. In testing environments, that mismatch can create failures that look like equipment problems, such as resets, nuisance faults, or inconsistent operation.

At a utility facility, those disruptions matter. Test benches support maintenance and verification work where repeatable results and stable operating conditions are part of doing the job safely and correctly. The objective was to correct voltage at the point of use without creating unnecessary disruption to upstream facility power.

Why They Couldn’t Just “Use It Anyway” at 100V

When a device is receiving the wrong voltage, it may still power on, but that does not mean the system is operating correctly.

• Undervoltage can create unreliable behavior Test equipment may reset, fault, or behave inconsistently when the supply is below what it expects.

• Troubleshooting time increases Teams can spend time chasing “equipment issues” that are actually power-related.

• Voltage mismatch can mask the true root cause A measured ~100V condition can be caused by voltage drop, circuit conditions, or other upstream issues that must be understood.

• Utility work requires repeatability In test and maintenance environments, stable electrical conditions support consistent results and safer workflows.
  

Because the workstations required dependable performance, correcting the mismatch was the practical path forward.

The Solution: Buck/Boost Voltage Correction (100V → 120V)

We supplied buck/boost transformers configured to boost a nominal ~100V input toward a nominal ~120V output at the workstation.

A buck/boost transformer is typically an autotransformer used for small, fixed voltage correction by adding or subtracting a winding voltage. It is important to understand what it does and does not do.

• It provides fixed voltage correction rather than dynamic regulation.

• It does not provide galvanic isolation.

• It does not create a neutral or create new 120V branch circuits.

• It does not change phase or frequency.

Because this correction was approximately 20%, it was treated as a careful application at the upper end of common buck/boost use cases. Output voltage depends on the actual input voltage under load and the wiring configuration, so verification under operating conditions is essential.

Why a Buck/Boost Transformer Was the Right Choice

• Point-of-use correction without refeeding the facility The mismatch was localized to a workstation, so correcting voltage where the equipment is used avoided unnecessary upstream electrical changes.

• A standard approach for small corrections Buck/boost transformers are commonly used to correct modest voltage differences when selected and wired per the manufacturer’s diagram and nameplate.

• Supports repeatable testing conditions Delivering the voltage the equipment expects reduces nuisance behavior and improves consistency at a test bench.

• Fast implementation compared to service changes Correcting voltage at the point of use is often faster than redesigning distribution for a single workstation.

• Reduces time spent troubleshooting power-related behavior Correcting undervoltage helps teams avoid wasted time diagnosing symptoms that originate from supply mismatch.

  
  

The Results

The voltage correction approach supported more reliable test bench operation at the Thunder Bay facility.

• Improved workstation voltage conditions The bench supply was corrected toward the 120V nominal requirement of the equipment.

• Reduced nuisance behavior Correcting undervoltage reduced the risk of resets, faults, and inconsistent operation tied to low supply voltage.

• Point-of-use solution implemented The fix addressed the mismatch at the workstation without unnecessary changes to broader facility power.

• Better repeatability for test work Stable operating conditions support consistent testing and maintenance workflows.

This case demonstrates a common reality even in sophisticated facilities: localized voltage mismatches happen, and a targeted correction method can restore stable operating conditions without turning the fix into a facility-wide project.

Why 100V-to-120V Mismatches Can Occur in Real Facilities

Nominal voltages and measured voltages do not always match at the point of use, especially as systems evolve.

1. Workstations change over time Equipment may be added, relocated, or replaced, and requirements may no longer match the original circuit intent.

2. Voltage drop can reduce point-of-use voltage Long runs, high current, and undersized conductors can cause a meaningful drop between the panel and the bench.

3. Circuit conditions can create unexpected readings Loose connections or other upstream issues can produce lower-than-expected voltage at the load.

4. Buck/boost is fixed correction, not regulation If the input varies, the corrected output varies as well, which is why measurement under load and verification matter.

This is why voltage correction projects should confirm the measured voltage under load and the equipment’s required voltage before selecting a correction approach.

Frequently Asked Questions

What is a buck/boost transformer?

A buck/boost transformer is a compact transformer commonly used for fixed voltage correction. It adds (boosts) or subtracts (bucks) a small amount of voltage so the supply better matches equipment requirements.

Can a buck/boost transformer boost ~100V to ~120V?

Yes, conceptually it can add approximately 20V of correction. Because this is about a 20% correction, it should be selected and verified carefully based on measured input voltage under load and the required output.

Does a buck/boost transformer provide isolation?

No. Buck/boost transformers are commonly applied as autotransformers for voltage correction rather than as isolation transformers.

Does a buck/boost transformer create a neutral or make 120V circuits?

No. A buck/boost transformer corrects voltage but does not create a new neutral or convert a system into standard 120V branch circuits.

What information is needed to quote a voltage correction solution for a test bench?

Typically: measured input voltage under load, required equipment voltage, phase, load current, duty cycle, and any constraints related to installation environment and enclosure needs.

Key Takeaways

• Major utilities still face localized voltage mismatches Point-of-use conditions can differ from nominal building voltage.

• Undervoltage can disrupt testing Resets and inconsistent behavior can be power-related, not equipment failure.

• Buck/boost provides fixed correction It can boost ~100V toward ~120V when selected and verified carefully.

• It is not isolation or regulation Buck/boost does not provide galvanic isolation, create a neutral, or dynamically regulate voltage.

• Measurement under load matters Confirming real input voltage and required voltage is essential for a correct correction approach.

Buck/boost transformers are a standard, permanent method of correcting small voltage mismatches so equipment can operate under the electrical conditions it was designed for.To learn more about solving voltage mismatch challenges for your equipment, contact Sanzo Sales.