OTLM Device

OTLM device measures temperature, sag and current of power lines simultaneously. Measurements are performed directly at the OTLM fixing points on the OHL phase conductor and are transmitted to the OTLM Centre via available communications channels with the exact GPS time stamp. The current transformer and the supplying unit provide power supply for the operation without any other outside source of power supply. Housing is made of fire resistant composite material for heavy ambient conditions. In case of communication failure data is stored locally in OTLM. LED lights on housing are used for local visual control of operation. Design of OTLM and positioning of temperature sensors neutralize any possible effect of ambient on precision of temperature measurements of conductor. Installation is simple and fast.

OTLM device architecture

  • Measurement unit (conductor temperature, conductor current, sag)
  • CPU and communication with GSM/GPRS, optics (OPGW),WiFi
  • Power supply with current transformer
  • Housing with fixing system
OTLM device technical data

  • Outside diameter 305mm
  • Length 300 mm
  • Weight approx.9.0 kg
  • Diameter of a conductor from 15,0 mm to 45,0 mm
  • Operating voltage level from 110 kV to 400 kV
  • Frequency 50 Hz (60 Hz)
  • Operating Ambient temperature range from – 40 ºC to +85 °C
  • Power Supply (current transformer) – Minimum operational current in conductor 65 A
Conductor temperature measurement

  • Conductor temperature measurement range from – 40 ºC to+125 ºC
  • Conductor temperature measurement resolution 0,5 ºC
  • Conductor temperature measurement deviation ±2.0 ºC
Conductor current measurement

  • Conductor current measurementrange from 65 A
  • Conductor current measurement resolution 1 A
GPS position and UTC clock

  • Addtional two-stage sending interval – triggered by temperature of conductor (T > and T>>)
Housing and other benefits 
  • Fireresistant composite material
  • Low maintenance
  • Remote diagnostic
Sag and tension
  • Sag accuracy – conductor diameter/2
  • Tension accuracy – less then 1%

Tested in accordance with:

  • IEC 60068-2-1:2007
  • IEC 60068-2-2:2007
  • IEC 60068-2-30:2005
  • IEC 60060-1:1989
  • IEC 60060-2:1994
  • IEC 60071-1:2006
  • CISPR 18-2:1986
  • IEC 61284:1997
  • IEC 60437:1997
  • EN 61000-6-2:2005
  • EN 61000-6-3:2007

Top part OTLMTool setMiddle inox screw

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OTLM conducted testOTLM conducted testOTLM conducted test