Continuous, real-time partial discharge detection and insulation diagnostics for MV & HV switchgear, transformers and power cables — UHF, TEV and ultrasonic sensing combined with integrated temperature monitoring. Detect insulation degradation weeks before catastrophic failure.
Partial discharge (PD) is a localized electrical discharge that occurs within or on the surface of insulation systems when the local electric field exceeds the dielectric strength of a small region — but does not bridge the full gap between conductors. Although each individual PD event releases relatively low energy, the cumulative effect of repetitive discharges irreversibly erodes insulation material through physical bombardment, chemical attack, and thermal damage.
Inside medium-voltage and high-voltage switchgear, PD activity generates measurable physical phenomena — electromagnetic radiation in the UHF band, transient earth voltage (TEV) pulses, acoustic (ultrasonic) emissions, light, ozone, and heat — each of which provides a detectable signal for partial discharge monitoring instruments.
Partial discharge in switchgear does not announce itself to operators. It develops silently inside sealed enclosures — invisible, inaudible, and undetectable by conventional measurement techniques — until the moment of catastrophic failure.
PD activity causes progressive molecular erosion of epoxy resins, cast resin insulators, cable sheaths, and busbar insulation. The degradation is self-reinforcing — each PD event creates a slightly larger void, leading to higher charge magnitude and more frequent discharge activity over time. Online PD monitoring is the only way to catch this process early.
Infrared thermography, visual inspection, and resistance measurement all require the fault to have progressed to an advanced thermal or mechanical stage. Partial discharge monitoring detects insulation faults at their earliest stage — when intervention is cheap, planned, and safe.
A single undetected insulation failure in MV switchgear can trigger an arc flash destroying an entire switchroom, incurring equipment replacement costs of hundreds of thousands of dollars, production losses measured in millions, and potentially fatal personnel injuries. The ROI of a PD monitoring system is typically recovered with the first prevented fault.
Power utilities, industrial facility managers, and data center operators increasingly face regulatory requirements and insurance conditions mandating continuous insulation monitoring for critical MV and HV assets. Switchgear partial discharge monitoring satisfies these requirements while directly reducing insurance premiums and demonstrating asset diligence.
Multiple physical phenomena accompany each partial discharge event. INNO's integrated partial discharge monitoring system captures the three most reliable and practically deployable signal types simultaneously — providing cross-validated, high-confidence insulation diagnostics.
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UHF PD monitoring captures electromagnetic radiation emitted by partial discharge events in the 300 MHz–3 GHz frequency band. Because the UHF band is far above the frequency of industrial interference sources, UHF sensors achieve exceptional signal-to-noise ratio in real substation environments.
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PD events inside metal-clad switchgear cause transient voltage pulses to appear on the outer surface of the enclosure — known as transient earth voltage (TEV). TEV sensors detect these pulses through capacitive coupling, providing a non-intrusive external measurement method for partial discharge monitoring.
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Partial discharge events generate acoustic emissions in the 20–300 kHz ultrasonic frequency range. Acoustic sensors mounted on the switchgear enclosure detect these emissions and allow precise physical localization of the PD source — identifying which specific component is discharging.
| Attribute | UHF Monitoring | TEV Monitoring | Ultrasonic (AE) | INNO Integrated PD System |
|---|---|---|---|---|
| EMI Immunity | ✓ High | ⚠ Medium | ✓ High | ✓ Maximum (multi-domain) |
| PD Source Localization | ✓ Yes (TDOA) | ✗ Limited | ✓ Yes (acoustic) | ✓ Full 3D localization |
| Installation Method | Internal (magnetic) | External (surface) | External (surface) | Combined — flexible |
| Sensitivity (pC) | ~100 pC | ~300 pC | ~500 pC | 100 pC (UHF primary) |
| False Alarm Rate | Low | Medium | Low | Very Low (cross-validated) |
| Temperature Monitoring | ✗ No | ✗ No | ✗ No | ✓ Integrated (±0.5°C) |
| SCADA Integration | ⚠ Varies | ⚠ Varies | ⚠ Varies | ✓ Modbus RTU / IEC 61850 |
| Battery-Free Operation | ⚠ Varies | ⚠ Varies | ⚠ Varies | ✓ Wired — maintenance-free |
INNO's integrated partial discharge and temperature monitoring system combines multi-domain PD sensing with fluorescent fiber optic temperature measurement in a single intelligent hardware platform. The "three-in-one" integrated sensor achieves simultaneous UHF, TEV/acoustic, and temperature acquisition from each monitored switchgear bay — eliminating separate hardware installations and reducing total system cost.
| Temperature Measurement Range | -50°C to +150°C |
| Temperature Accuracy (0~85°C) | ±0.5°C |
| Temperature Accuracy (-40~125°C) | ±1°C |
| PD Measurement Range | 100 pC – 5000 pC |
| PD Measurement Accuracy | ±10% |
| Default PD Alarm Threshold | 300 pC (configurable) |
| PD Detection Methods | UHF / TEV / Ultrasonic (AE) — integrated |
| Host Synchronization | Internal synchronization / Wireless synchronization |
| Power Frequency Synchronization | Built-in lithium sub-battery backup |
| Communication Protocols | Modbus RTU · RS485 · LoRa |
| Wireless Range (open area) | Within 600 meters |
| Protection Rating | IP66 |
| Sensor Type | Three-in-one integrated smart sensor |
| Installation Method | Magnetic adhesion — no panel outage required |
| Data Upload | Mean value, peak value, alarm level, trend graph |
| Certifications | CE · RoHS · ISO 9001 · ISO 14001 · ISO 45001 |
The integrated smart sensor achieves multi-dimensional acquisition from a single compact unit per switchgear bay. Configuration and parameter adjustment are supported via RS485 Modbus RTU — no proprietary software or hardware required.
Simultaneous UHF, transient earth voltage (TEV) and ultrasonic (AE) signal acquisition with time-stamped data uploads of mean, peak and alarm-level values for every collection interval.
Fluorescent fiber optic temperature probes embedded alongside PD sensors provide simultaneous ±0.5°C thermal measurements — correlating PD activity directly with temperature rise at the same physical location.
Supports RS485 Modbus RTU for wired substation SCADA integration and LoRa for wireless mesh communication up to 600 m — enabling flexible PD monitoring deployment without cable routing constraints.
On-device diagnostic algorithms perform multi-dimensional comparative analysis across UHF, TEV and AE channels — enabling automatic insulation defect classification and severity assessment with push-notification alarm outputs.
From urban distribution substations in Europe to industrial switchgear in Asia Pacific — INNO partial discharge monitoring systems operate continuously across diverse environments, delivering reliable insulation diagnostics in the most demanding power applications.
A major distribution network operator in New South Wales required a continuous insulation monitoring solution for its fleet of 11 kV ring main units and primary distribution switchgear serving approximately 120,000 customers. Repeated cable plug termination failures had caused a series of unplanned outages, each affecting tens of thousands of customers and incurring regulatory penalties under the national quality of supply framework.
INNO three-in-one integrated PD and temperature monitoring systems were deployed across 22 priority substations. UHF sensors were installed magnetically inside each cable chamber, with TEV sensors fitted externally for supplementary confirmation. All units communicated via LoRa wireless to a gateway, forwarding data to the operator's central asset management platform via Modbus RTU. Within the first six months, the system identified elevated UHF activity at three cable plug terminations — confirmed as early-stage insulation carbonization. Planned interventions prevented all three from developing into forced outages.
A major petrochemical production facility in the Rhine-Ruhr region installed INNO's partial discharge and temperature monitoring platform across its 10 kV medium-voltage switchgear network serving process-critical drives, compressors, and utilities. The facility had experienced two insulation-related switchgear failures within three years — both resulting in multi-day process shutdowns with estimated total losses exceeding €2.5 million per incident.
The INNO system was integrated with the plant's Siemens PCS 7 DCS via Modbus RTU, delivering real-time PD activity data alongside fiber optic temperature readings from every busbar and cable termination point. The integrated diagnostic algorithm flagged developing PD activity at a 10 kV motor feeder cable joint after six weeks — temperature correlation showed a simultaneous +8°C rise at the same location. Maintenance intervention during a scheduled turnaround confirmed extensive void discharge damage to the cable joint insulation. The facility has reported zero insulation-related outages in the 24 months since commissioning.
A Tier IV data center operator in Singapore's data center cluster required an online partial discharge monitoring solution for its 22 kV medium-voltage switchgear serving 60 MW of critical IT load. The operator's lease requirements with tenants mandated continuous insulation monitoring as a condition of Tier IV certification, and the high ambient humidity of the Southeast Asian climate represented an elevated risk of moisture-related insulation degradation inside switchgear enclosures.
INNO integrated PD and temperature monitoring units were deployed across all main and distribution switchgear bays. The system communicated via RS485 Modbus RTU to the facility's BMS and simultaneously to the operator's cloud-based asset health dashboard. The high-sensitivity UHF channel detected early-stage surface discharge activity on an incoming cable stress cone within four months of operation — attributed to condensation ingress during a maintenance procedure. Immediate targeted drying and re-termination prevented a forced outage affecting multiple hyperscale tenants. The operator subsequently extended the INNO monitoring platform to two additional Singapore facilities.
Contact our application engineers — they'll analyze your switchgear type, bay count and existing SCADA architecture to design the right PD monitoring system for your specific requirements.
INNO's partial discharge surveillance systems are engineered for every critical high-voltage asset category — from switchgear and transformers to power cables and GIS installations. One monitoring platform covering your entire high-voltage infrastructure.
Continuous partial discharge online monitoring for 6 kV, 10 kV, 35 kV and higher voltage metal-clad switchgear. UHF sensors mount magnetically inside cable chambers and bus sections — no panel outage required. Covers all switchgear types including air-insulated, vacuum and SF6 switchgear.
Key monitoring points: cable plug terminations, busbar insulation, circuit breaker interrupters, voltage transformer primary connections, and earth switch contacts.
Switchgear Monitoring Solutions →
Partial discharge online monitoring for oil-immersed and dry-type power transformers from distribution to transmission voltage class. INNO supports UHF sensors through oil-drain valve mounting, high-frequency current transformer (HFCT) sensors on bushing earth straps, and acoustic (AE) sensors on tank walls for comprehensive transformer insulation monitoring.
The monitoring system continuously tracks winding insulation, bushings, tap changer contacts and core insulation — providing a real-time transformer insulation health index for asset management decisions.
Transformer Monitoring Solutions →
High-voltage cable partial discharge online monitoring for XLPE and EPR insulated cables at 6 kV to 110 kV. HFCT sensors clamp onto cable earth straps at joint pits, sealing ends and cable terminations — providing continuous PD measurement without any cable modification or outage. Particularly effective for detecting PD at stress cone interfaces and factory joints.
The cable PD monitoring system has been validated across multiple substations and power plants with proven long-term stability — reliably detecting developing cable joint insulation faults before failure.
Inquire About Cable PD Monitoring →UHF sensors installed through standard dielectric windows or valve ports in SF6 gas-insulated switchgear provide highly sensitive partial discharge detection inside GIS enclosures. The high propagation velocity of UHF signals within SF6 gas enables precise fault localization — identifying the defective GIS compartment among hundreds.
GIS PD monitoring is complemented by INNO's SF6 gas leakage monitoring solution — the two systems together provide complete insulation condition surveillance for GIS substations.
SF6 Gas Monitoring Solutions →
Compact urban distribution ring main units present a particularly high PD risk environment — sealed enclosures, cable plug terminations under constant thermal cycling, and limited access for periodic inspection. INNO's miniaturized sensor package installs within the confined space of RMU cable chambers without modifying enclosure integrity.
Wireless LoRa communication eliminates cable management challenges in compact urban substations, making the INNO system the practical choice for large-scale RMU monitoring rollouts.
Send RMU Monitoring Inquiry →
Enclosed busducts and isolated phase bus (IPB) systems in power plant generator step-up circuits, large industrial facilities, and data center primary distribution require continuous PD monitoring for the encapsulated insulation systems that are otherwise completely inaccessible. UHF sensors and acoustic arrays provide non-intrusive surveillance of these critical power transmission pathways.
Integration with INNO's busbar temperature monitoring system delivers simultaneous thermal and electrical insulation condition data for the complete busduct system.
Busbar Monitoring Solutions →INNO fiber optic systems cover every critical monitoring dimension of modern switchgear — from thermal hotspots to arc flash detection and gas leakage. One platform. One manufacturer. Complete protection.
Real-time monitoring of circuit breaker contact temperature, mechanical wear and thermal anomalies. Early fault warning reduces arc flash risk and extends equipment service life.
Learn More →Precisely detect thermal hotspots at busbar joints, cable terminations and contact points before faults develop. Enable proactive preventive maintenance and eliminate unplanned outages caused by thermal defects.
Learn More →Continuously track busbar temperature distribution and insulation degradation trends. Ensure reliable power transmission across main and sectional busbars with IEC 61850 / Modbus RTU SCADA integration.
Learn More →Real-time arc flash detection and precise fault location for millisecond-speed protective response. Effectively prevent arc flash incidents from causing severe damage to equipment and personnel.
Learn More →Comprehensive temperature measurement across all critical switchgear assets for early detection of overheating and proactive maintenance. Fiber optic sensors rated to 140 kV — fully suited for high-voltage environments.
Learn More →Real-time tracking of SF6 gas leakage and concentration in gas-insulated switchgear. Ensure safe GIS operation and environmental compliance while reducing the risk of insulation failure.
Learn More →Continuous acquisition and analysis of partial discharge activity. Early identification of insulation defects through high-sensitivity UHF, TEV and ultrasonic sensors to reduce unplanned switchgear failures.
Learn More →A unified platform integrating temperature, partial discharge, arc flash, SF6 gas and mechanical condition monitoring into one dashboard. Multi-bay, multi-device visibility across an entire substation from a single system — with full SCADA / IEC 61850 integration.
Explore Full Platform →Founded in 2011 in Fuzhou, China, INNO Instrument — Fuzhou Innovation Electronic Science & Technology Co., Ltd. — is a vertically integrated manufacturer of fluorescent fiber optic temperature sensors, partial discharge monitoring systems, and integrated online monitoring platforms for power infrastructure worldwide.
With over 15 years of R&D investment and in-house production of fiber optic probes, PD sensors, multi-channel transmitters, and monitoring software, INNO supports global switchgear OEMs, EPC contractors, power utilities, and system integrators with fully customized sensing solutions. Our engineering team works directly with your design and procurement teams to deliver factory-calibrated, application-specific systems — ready to embed in your equipment from day one, with full OEM documentation, traceability records, and co-branding options.
Bespoke UHF antenna geometries, TEV coupler designs, and ultrasonic sensor configurations for factory embedding in RMU cable plugs, GIS spacers and switchgear panels.
Combined fluorescent fiber optic temperature and partial discharge sensing in a single sensor unit — co-developed with your switchgear design for seamless OEM integration.
Co-branded asset health dashboards and monitoring interfaces configured to your brand identity, protocol stack, alarm management requirements and customer-facing reporting formats.
Dedicated application engineering, FAT/SAT support, IQ/OQ qualification documentation, and ongoing post-deployment technical assistance for regulated and safety-critical installations.
End-to-end in-house production — from raw fiber and crystal processing through PD sensor assembly, software development and final system integration — gives INNO the flexibility and traceability that global OEM partners require.
From utility substations to hyperscale data centers — electrical professionals worldwide rely on INNO partial discharge monitoring to protect their most critical switchgear assets.
We deployed INNO's partial discharge monitoring system across 18 of our primary substations after a series of cable termination failures. Within three months, the UHF sensors identified two developing insulation faults that had completely escaped our annual IR inspection programme. The integration with our Schneider SCADA via Modbus RTU was straightforward — our team had the system live within a day of commissioning. It's now a permanent part of our asset management strategy.
The combined PD and temperature monitoring capability is what differentiated INNO from competing solutions. At our 20 kV switchgear network, we now have real-time correlation between thermal and electrical insulation data at every bay. The INNO team provided comprehensive engineering support through specification, installation and commissioning — and the alarm system has already caught one significant cable joint fault before it caused a process trip.
We specified INNO's partial discharge monitoring system for three of our industrial parks in Singapore after a successful trial at one facility. The wireless LoRa communication made rollout straightforward without major cabling works. The UHF sensitivity is noticeably better than the portable PD measurement instruments we previously used for periodic surveys — and with continuous monitoring we are now catching transient events that periodic surveys simply cannot detect.
INNO provided OEM-integrated PD monitoring modules for switchgear panels we supply to major petrochemical clients. The factory calibration quality, CE certification and complete documentation package met all our client's procurement requirements without exception. Response time from the INNO engineering team has been consistently excellent — we now use INNO's solutions as our standard embedded monitoring platform for all new switchgear deliveries.
INNO's quality management system, products, and environmental practices are independently audited and certified to the highest international standards — providing procurement teams and project engineers the documentation required for critical power infrastructure applications worldwide.
Quality Management System — certified manufacturing and product quality control ensuring consistent, traceable production at every stage.
Environmental Management System — verified responsible environmental practices across all manufacturing and operational processes.
Occupational Health & Safety Management — certified safe workplace practices protecting employees and contractors at all INNO facilities.
Information Security Management — certified data and intellectual property protection standards covering all OEM project and customer data.
European Conformity — all products comply with EU safety, health, and environmental protection requirements for sale and deployment across the European Union and EEA.
Restriction of Hazardous Substances — all products meet EU RoHS Directive requirements for restricted materials, supporting customer environmental compliance programs.
All PD monitoring sensors and fiber optic transmitters are calibrated in INNO's internal metrology laboratory against traceable reference standards before shipment. Every unit ships with a calibration certificate and full measurement traceability record.
Complete installation qualification (IQ) and operational qualification (OQ) documentation packages are available for regulated industry applications — supporting pharmaceutical, nuclear, food processing, and GxP-compliant facility deployments.
INNO transmitters have been independently verified for Modbus RTU interoperability and IEC 61850 GOOSE compliance against Siemens, ABB, Schneider and GE relay and SCADA platform families — ensuring reliable integration in any substation environment.
Fiber optic temperature probes are tested to 140 kV withstand voltage per IEC 60243 prior to shipping. Test certificates included with each delivery — providing the documentation required for HV switchgear and substation qualification packages.
Have a question about partial discharge monitoring for your specific application?
Our application engineers respond within 4 hours. Share your switchgear type, voltage level and bay count — we'll recommend the right PD monitoring configuration at no charge.
Share your switchgear type, voltage level and panel layout — receive a custom PD monitoring system configuration, bill of materials and quotation within one business day. Completely free, no commitment required.
Disclaimer：。 The technical specifications, case data and performance figures presented on this page are for reference only. Actual results may vary depending on installation environment, equipment condition and operating parameters. INNO reserves the right to update or modify product specifications without prior notice. Please contact us through official channels for formal quotations or technical confirmation.
