VTI-GL-100C Distributed Temperature Sensing (DTS)
Fibre-optic distributed temperature sensing
One armoured fibre gives a continuous temperature profile every 0.5 m over kilometres, with no electrical power and no electronics in the field.
Model VTI-TS-26
VTI-TS-26 Wireless Temperature Sensor for Transmission Lines
Conductor-connection monitoring · DLR input
Battery-free, self-powered wireless temperature sensor for conductor connections on 110–500 kV overhead lines and outdoor switchyards — hot-spot detection and a measured input to the utility’s dynamic line rating (DLR).
- IN865 band for India
- LoRa sub-GHzIN865 band for India
- Line-of-sight range
- Up to 3 kmLine-of-sight range
- Self-powered from line current, no battery
- ≥ 1 ASelf-powered from line current, no battery
- Overhead lines & switchyards
- 110–500 kVOverhead lines & switchyards
Authorised distributor of VTI Corporation (Vietnam)vti-sensors.com (opens in a new tab)
Overview
VTI-TS-26 at a glance
The VTI-TS-26 is a long-range, battery-free, self-powered wireless contact temperature sensor for outdoor substation switchyards (110 kV to 500 kV), transformer bushings and overhead transmission lines. It harvests operating energy from the conductor current from ≥ 1 A upward and transmits over LoRa sub-GHz — IN865 band for India — up to 3 km line-of-sight.
VTI-TS-26 provides measured temperature of conductor connections (splices, dead-ends, jumpers), for hot-spot detection and as a real-time input to the utility’s DLR / ampacity calculation (IEEE 738, CIGRE TB 601). The rating calculation also needs weather data and the utility’s own rating engine.
Installation
Installation points on 110–500 kV lines
Mid-span tension splices
Overhead transmission line mid-span tension splices.
Dead-end clamps
Dead-end tension clamps at the line terminations.
Jumper loops
Jumper loop clamps and gantry down-leads.
Also used in outdoor switchyards
- Transformer high-voltage bushing palms (110 kV, 220 kV, 500 kV)
- Outdoor disconnect switch (isolator) moving jaws and blades
- Surge arrester and instrument transformer header terminal clamps
What “supports DLR” means
VTI-TS-26 supplies the measured connection temperature. The DLR / ampacity rating itself is calculated by the utility’s own rating engine, which also needs weather data.
Installation safety
All VTI clamp-on sensors are installed with the circuit isolated, earthed and proved dead, consistent with IEEE Std 2969-2025.
Key Features
- Measured temperature of conductor connections — splices, dead-ends and jumpers
- Hot-spot detection and a real-time input to the utility’s DLR / ampacity calculation
- Self-powered from line current ≥ 1 A by current-transformer energy harvesting — no battery
- LoRa sub-GHz radio, IN865 band for India, range up to 3 km line-of-sight
- Type-tested to 500 kV; partial discharge 8.7 pC at 500 kV (acceptance criterion < 10 pC)
- Clamp-on mounting with stainless-steel locking ties; IP68 outdoor construction
Brochure & Enquiry
Talk to our team in Chennai about sizing, integration and pricing for VTI-TS-26.
Datasheets and type-test reports for VTI-TS-26 are not public and are available on request.
Authorised distributor of VTI Corporation (Vietnam)vti-sensors.com (opens in a new tab)
Specifications
As published by VTI Corporation.
Key specifications
- Model Name
- VTI-TS-26 (VTI-TS series, previously catalogued as TBR22 / TBR22-STE / TBR22-BTE)
- Power Supply
- Current-transformer induction energy harvesting, 100% battery-free
- Minimum Start Current
- ≥ 1 A primary alternating current on monitored conductor
- Measuring Temperature Range
- −40 °C to +125 °C
- Measurement Accuracy
- ±0.2 °C within −10 to +65 °C; ±0.5 °C across rest of range
- Operating Ambient Temperature
- −40 °C to +85 °C; humidity 0–100% (IP68)
- Type-Tested System Voltage
- Type-tested to 500 kV (EHV / UHV qualified)
- Partial Discharge at 500 kV
- 8.7 pC (acceptance criterion < 10 pC)
- Lightning Impulse Withstand
- −1500 kV standard full wave impulse
- Wireless Protocol
- LoRa sub-GHz (AS923, IN865, EU868 configurable per country)
- Transmission Range
- Up to 3 km line of sight in unobstructed substation switchyards
- Radio Compliance
- Duty cycle < 1%, Listen-Before-Talk (LBT), regional EIRP limits
- Reporting Interval
- Adaptive, 5 to 30 minutes (dynamic acceleration during thermal surges)
- Mounting Method
- Clamp-on with stainless-steel locking ties and high-field magnetic grip
- Installation Safety Requirement
- Installed strictly with the circuit isolated, earthed, and proved dead during planned outages
- International Standards
- CIGRE Technical Brochure 999 Table 2.8-1, IEEE Std 2969-2025, NFPA 70B
- Host Gateway
- VTI Gateway GW22-D dual-band (Modbus TCP, MQTT over TLS, IEC 60870-5-104)
Standards
Standards references
IEEE 738 · CIGRE TB 601
Thermal rating methods for overhead conductors, used in the utility’s DLR / ampacity calculation. VTI-TS-26 provides the measured connection-temperature input.
IEEE Std 2969-2025
Guide for continuous thermal monitoring. VTI clamp-on sensors are installed with the circuit isolated, earthed and proved dead, consistent with IEEE Std 2969-2025.
CIGRE TB 999
Lifelong Supervision and Management of Substations by Use of Sensors — Table 2.8-1 references the energy-harvesting thermal sensor.
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