High Voltage Transmission Tower Monitoring

Application Notes

Application Background                                                                                                                                                                                          Printer Friendly Version

Electricity Utility companies need to monitor the high voltage transmission towers for several reasons.

high voltage transmission tower monitoring

There is often a need or desire to monitor the transmission voltages and currents to assist with the management of the transmission network.

There may also be a need to monitor the physical stability of the tower by using accelerometers or some other seismic instrument which may measure earth tremors, and any local condition which causes instability, for example high winds, floods or perhaps vandals damaging the structure.

There are some circumstances where vandals damage the towers by removing / stealing parts of the structure to be sold as scrap metal. Aluminum may be stolen and copper especially is often stolen as it is a valuable metal.
As well as sensors it may be desirable to have some level of video surveillance.

Transmission Tower Monitor

Unidata has received many requests for enhanced remote monitoring with images for remote measurement industrial equipment Such requests are driven by the need to see what is happening on the sites to confirm measurement instrument readings, and to have a regular, perhaps daily, image of the tower base to check for any damage.

The ambient weather conditions can also be measured, especially the wind speed and direction and this measurement can be achieved simply with a modern ultrasonic weather transmitter, which does not have any moving parts.

Application Detail

The voltage and current monitoring application is routine, and can be accomplished using a direct connection to conductors to measure the voltage or by measuring the field effect surrounding a high voltage conductor. For the direct connection there are many instruments designed to measure direct voltages, however installation of such devices required special safety planning which may be difficult.

For the field effect method, there is no direct connection to the conductor required. The higher the voltage on the conductor, the stronger the field and the greater distance from which it can be detected, for example a typical overhead distribution line at 11,000 volts and 11 meters up in the air, the average electric field strength beneath the line would be 11,000 volts / 11 meters or about 1000 volts/meter. There are many other factors affecting the measurement but the example illustrated the process.

Transmission Lines

The tower stability can be measured using any general purpose accelerometer, which detects small movements in the tower structure. If the tower is in a region prone to earthquakes, seismic instrument can be added to monitor earth movements.

To monitor the any vandals stealing metal parts, a low resolution video camera or cameras can be added to take a photograph of the structure every hour as a permanent record of the structure, to be available for engineers at a central location to view routinely to check for any damage to the structure.

All of the instruments can be used together to determine the stability of the structure, for example a brief disturbance in the structure would be recorded by the accelerometer and the data from all the sensors can be correlated to determine the likely cause. All of the instruments would be mounted on the tower structure, along with a small solar panel and backup battery so the power system remained independent.

Unidata-High Voltage Transmission Tower Monitoring.jpg

A Neon Remote Terminal would be connected to the sensors via SDI 12, Modbus and or Analog and digital inputs, along with a choice of cell phone or satellite modem equipment, to scan the instruments and check for any unusual out of limits readings and also routinely send the data to a central Neon Server at the headquarters of the electricity utility for display on a web browser. The data could also be sent, perhaps once per minute, via web services or FTP to other processing systems for example to the main SCADA system used by the electricity utility.

Typical Configuration

Options for Application Specific Instruments / InputsUnidata Part NumberDescription
Vaisala Weather Transmitter WXT520 measures barometric pressure, humidity, precipitation, temperature and wind speed & direction6501V-HVaisala Weather Transmitter RS232/422/485 SDI-12
Field Effect Voltage SensorsVariousAnalog or Digital Outputs
AccelometersVariousAnalog or Digital Outputs
Small Power Monitor RTUVariousModbus Output Field Effect Meters
Seismic InstrumentVariousAnalog or Digital Outputs
RS232 Camera with 3G NRT2502A-3E-LNeon Camera System with 3G NRT
Ethernet Camera2502BIP Camera
Options for Neon Telemetry - NRT / RTU / Field UnitsUnidata Part NumberDescription
Cellular RTU 3G2013F-AB03Neon Metering Module 3G with Antenna and Li Battery
Cellular RTU 4G2013F-AB04Neon Metering Module 4G with Antenna and Li Battery
Cellular RTU 3G - Industrial2016F-AB03Neon Remote Terminal 3G with Antenna and Li Battery
Cellular RTU 4G - Industrial2016F-AB04Neon Remote Terminal 4G with Antenna and Li Battery
Low Earth Orbit Satellite Globalstar2015E-AB0Neon Remote Terminal - Satellite Globalstar Modem with Antenna and three Li Batteries
Ethernet2017E-0B0-1 or 3NRT Ethernet with single or triple Ethernet Ports
with three Li Batteries
Equatorial Orbit Satellite - Inmarsat2018E-AB0-1 or 3NRT Ethernet with single or triple Ethernet Ports
with three Li Batteries
LCD Display2500ENRT LCD Display
NRT Field Termination Strip2103F2015E,2016F,2017E, and 2018E NRT FTS
NRT Firmware Option2303A-8M8M Extended Memory Option
NRT Firmware Option2303A-8M-CAM8M Extended Memory & Serial Camera Option
NRT Firmware Option2303A-CAMSerial Camera Option
Options for Neon Application Software - Customer ServerUnidata Part NumberDescription
Neon Application Software2302ANeon Server Software Licence Incl 5 NAL
Neon Application Software2302A-10Additional 10 NRT Access Licences
Neon Application Software2302A-20Additional 20 NRT Access Licences
Neon Application Software2302A-50Additional 50 NRT Access Licences
Options for Neon Application Software - Unidata ServerUnidata Part NumberDescription
Neon Application Software2301ANeon Data Initial Subscription Setup Fee
Neon Hosting Service2301A-01Neon Data Service Fee for 1-50 NRTs
Neon Hosting Service2301A-02Neon Data Service Fee for 51-100 NRTs
Neon Hosting Service2301A-10Neon Data Service Fee Metering
Options for Conventional Dataloggers / Field UnitsUnidata Part NumberDescription
Standards Starlogger6004D-11Red Logger 512K with Alkaline Battery
Display Starlogger6004D-21Blue Logger 512K with LCD and Alkaline Battery
Prologger7001D-11Green Logger 1M with LCD and Alkaline Battery
Micrologger8010C-EURMicrologger 512K
Starlogger Field Termination Strip6103E6004D FTS
Prologger Field Termination Strip7100E7001D FTS
Starlog V4 Management Software6308A-AUEStarlog V4 Full Licence Key