High-voltage and strong-EMI fiber optic temperature measurement system

SOLUTION

High-Voltage Equipment
Temperature Monitoring

Fluorescent fiber optic temperature measurement for high-voltage, strong-EMI and RF environments where conventional electrical sensors may be unreliable. This optical path supports EMI/RFI immune temperature measurement and electrically isolated temperature measurement for power equipment testing, laboratories, industrial systems and other demanding applications.

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ElectricalIsolation

EMIImmunity

No Metal atSensing Tip

Reliable inStrong Fields

THE CHALLENGE

Why Conventional Electrical Sensors Struggle in EMI Environments

High-voltage systems, power electronics, RF equipment and electromagnetic test setups generate intense electrical noise and potential. Conventional sensors with metal conductors can pick up noise, create ground loops and even pose safety risks.

FactorConventional Electrical SensorsFiber Optic Measurement

Electrical Isolation×　Requires electrical connection (ground loops, leakage risk)✓　Fully electrically isolated (intrinsically safe)

EMI / RF Susceptibility×　Susceptible to EMI, RF, EFT and surge✓　Immune to EMI, RF, EFT and surge

Safety in High Voltage×　Metal conductors can float to high potential✓　Non-conductive sensing; no spark-over path

Signal Stability×　Noise and ground loops affect accuracy✓　Stable, drift-free measurements in harsh EMI

Installation Suitability×　Requires shielding, grounding and complex routing✓　Lightweight dielectric fiber; easy to route

Targeted Solutions for Electrically Demanding Environments

Precision temperature monitoring where electrical noise, high voltage and safety concerns make conventional sensors unreliable.

High-voltage test laboratory using interference-resistant temperature measurement

Stable Temperature Measurement in
High-Voltage Test & EMI-Rich Environments

INNO fiber optic solutions deliver accurate, drift-free temperature data in environments with strong electromagnetic interference and high electrical potential. The passive optical sensing path keeps conductive wiring away from the measurement point, supporting dependable monitoring without compromising operator or equipment safety.

Electrical isolation at the sensing point helps protect personnel and connected test equipment
Immunity to strong EMI and RF fields supports stable, interference-resistant temperature data
Direct point measurement captures temperature at critical components inside conductive setups
Safer monitoring where conventional electrical sensors are unsuitable, unreliable or restricted

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Application-Specific Configuration for
Lab, MRI, Microwave and Industrial Systems

We design EMI-immune temperature measurement solutions around your system architecture, installation space, sensing locations and monitoring workflow. Each configuration can combine suitable probes, optical routing, instruments and data interfaces for laboratory, medical, microwave and industrial equipment.

Probe selection matched to the measurement point, temperature range and operating environment
Compatible transmitter and display options for laboratory, rack, panel or field installation
Integration with PLC, DAQ or SCADA platforms for centralized monitoring and data review
Mechanical layout, enclosure and installation configuration adapted to the equipment structure

APPLICATIONS

Where EMI-Immune Measurement Matters

From research labs to industrial systems, fiber optic temperature sensing delivers reliable, isolated data where electrical sensors cannot.

High-Voltage Test Labs

Accurate temperature monitoring on HV components under extreme voltage stress.

MRI & Medical RF Systems

Non-conductive sensing inside MRI and RF environments without image interference.

Industrial Microwave Equipment

Monitor temperature in waveguides, cavities and resonant systems without disturbing RF fields.

Power Electronics Cabinets

Track hotspot temperatures in IGBTs, SiC modules and busbars in high-frequency environments.

Transformer Winding Monitoring

Monitor winding hot spots and internal temperature points in electrically demanding transformer environments.

Generator / Motor Test Stands

Reliable temperature data in high-power rotating machines during validation and endurance testing.

KEY MEASUREMENT CHALLENGES

Temperature Measurement Challenges

Electrical interference, high voltage and complex installations can make conventional temperature measurement difficult.

Strong EMI & RF Fields

Electrical signals can be affected by electromagnetic interference.

High Electrical Potential

Electrical sensors may require additional isolation in high-voltage environments.

Long Cable Routing

Conductive cables can pick up interference over long distances.

Electrical Noise

Noise can affect stable and reliable temperature measurements.

Why the Method Remains Immune in Strong Fields

No Conductive Path

No metal at the sensing point eliminates direct conduction of EMI or surge energy.

No Ground Loop

Optical isolation breaks ground loops and common-mode voltage paths.

Immune to RF Coupling

Light in fiber is unaffected by electric, magnetic or RF fields.

High-Voltage Safe

Dielectric construction withstands high common-mode voltages.

Stable Long-Distance Routing

Fiber enables long runs in harsh routes without signal degradation.

Reliable Repeatability

High repeatability with minimal drift under demanding conditions.

Typical Deployment Models

Bench Validation

Temperature verification during component and high-voltage laboratory tests.

Rack-Mounted Test System

Centralized multi-channel acquisition for repeatable test programs.

OEM Equipment Integration

Compact sensing modules integrated into customer equipment and controls.

Permanent Industrial Monitoring

Continuous isolated measurement around energized production assets.

PROJECT PLANNING

How to Specify a High-Voltage & EMI-Immune Project

Measurement Location

Where is temperature measured?

Voltage Level

Nominal operating voltage and test voltage?

EMI / RF Source

Type, frequency range and severity?

Expected Temperature Range

Minimum / maximum temperature and operating conditions?

Cable Routing Distance

Sensor-to-instrument distance?

Installation Space

Rack, panel, enclosure and access constraints?

Required Response Time

How fast should the system respond?

Output / Integration Needs

Interfaces, protocols and system integration?

Engineering Review Checklist

01Measurement points and critical components identified○

02Voltage class and isolation requirements confirmed○

03EMI / RF environment characterized○

04Temperature range and accuracy requirements defined○

05Fiber routing path and distance verified○

06Mounting, enclosure and environmental constraints checked○

07Response time and data logging requirements confirmed○

08System outputs and integration interfaces specified○

TECHNOLOGY COMPARISON

When Fiber Optic Measurement Is the Better Choice

CriteriaThermocouplesRTDsFiber Optic Sensors

Electrical IsolationExtra isolationExtra isolationDielectric

EMI / RF ImmunityShielding neededShielding neededImmune

High-Voltage UseLimitedLimitedWell suited

Signal CableConductiveConductiveOptical

Strong Fields / RFLimitedLimitedWell suited

PROJECT IMPACT

Typical Project Outcomes

30–60%

Cleaner Temperature Data

Eliminate EMI noise and measurement errors for more accurate results.

100%

Improved Electrical Safety

Galvanic isolation removes ground loops and high-voltage shock risks.

40–70%

Easier Qualification Testing

Fewer re-tests due to EMI issues and unreliable measurements.

Long-Term

Reliable Monitoring

Stable performance in harsh, high-voltage, and EMI-rich environments.

SOLUTION STRATEGY

Where This Solution Fits in a Complete Measurement Strategy

Combine EMI-immune measurement with other INNO solutions for a complete temperature monitoring system.

Direct Hot-Spot Monitoring

Capture critical temperatures at the exact point of heat generation.

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Multi-Point Temperature Monitoring

Scale from a few points to 64 independent channels.

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PLC & SCADA System Integration

Integrate temperature data into control and monitoring platforms.

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Custom & OEM Temperature Sensing

Build fiber optic sensors and systems around unique requirements.

RECOMMENDED EMI-IMMUNE PRODUCTS

Fiber Optic Temperature Products for Electrically Demanding Environments

Standard Fluorescence Fiber Optic Temperature Probe

A passive, non-conductive point probe for reviewed temperature locations in high-voltage and strong-EMI environments.

Multi-Channel Fiber Optic Temperature Transmitter

Processes separate fluorescence probe channels and provides configurable display, alarm and communication functions.

Fiber Optic Temperature LCD Display Instrument

Provides local temperature visibility in a panel format for a reviewed fiber optic temperature measurement arrangement.

Microwave EMI-Immune Fiber Optic Temperature Monitoring System

A configured optical temperature monitoring system for microwave, RF and other strong electromagnetic-field projects.

APPLICATION REVIEW

Discuss Your High-Voltage Equipment Application

Share the measurement location, electrical environment, sensing points and required outputs so our engineers can recommend a suitable fiber optic monitoring configuration.

FAQ

High-Voltage & EMI-Immune Measurement FAQs

Why are fiber optic sensors immune to EMI?⌄

The sensing path is dielectric and carries light rather than an electrical measurement signal, so electromagnetic and radio-frequency fields do not induce measurement noise in the probe.

Can they be used near high-voltage conductors?⌄

Yes. The passive, non-conductive probe can be reviewed for selected measurement points near energized equipment where electrical isolation is required.

What temperature range is available?⌄

The standard available temperature range is -40°C to +260°C. For applications requiring a wider range, contact INNO to review a custom probe and system configuration.

Can this solution be used for transformer winding temperature measurement?⌄

Yes. A passive, non-conductive fluorescence probe can measure a selected winding hot spot directly while the optical sensing path remains resistant to electromagnetic interference and electrically isolated from the monitored point.

Can data be sent to PLC or SCADA?⌄

Yes. Reviewed monitoring hosts can provide industrial communication and alarm outputs for PLC or SCADA integration.

Are the sensors suitable for RF and microwave systems?⌄

Yes. Their passive optical sensing path is suitable for RF, microwave and strong-EMI environments when probe placement and materials are reviewed.

Where can this solution be applied?⌄

It can be used for transformer windings, switchgear and busbar connections, motors and generators, high-voltage test equipment, power electronics, MRI and RF systems, and industrial microwave or induction-heating equipment.

What measurement accuracy is available?⌄

Depending on the selected probe and monitoring instrument, the available measurement accuracy is typically ±0.5°C to ±1.0°C.

Review a High-Voltage Measurement Configuration

Share the equipment, measurement points and EMI conditions so engineering can specify a suitable monitoring path.

Contact Engineering →Request a Configuration →

Fluorescent Fiber Optic Temperature Sensing Technology →

High-Voltage EquipmentTemperature Monitoring