High Voltage Transmission Tower Monitoring

Application Notes

Application Background

Electricity utility companies need to monitor the high voltage transmission towers for several reasons. 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 seismic instruments which measure earth tremors, strong winds or perhaps vandals damaging the structure.
There are some instances where vandals damaged the towers by removing / stealing parts of the structure to be sold as scrap metal.

As well as having monitoring sensors it may be desirable to have some level of video surveillance. 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 to check for any damage. The ambient weather conditions can also be measured, like temperature, humidity, wind speed and direction. This can be achieved simply by using modern easily installed, all-in-one, ultrasonic weather transmitter.

Application Detail

The voltage and current monitoring is routinely performed and can be accomplished by directly connecting measurement instruments to conductors or indirectly, by measuring field effect surrounding a high voltage conductor. There are many instruments designed to measure voltages directly, however installation of such devices requires special safety planning which may be difficult.

Simpler approach would be to use instruments that measure field strength in close proximity to conductors rather than directly connecting to them. Electrical field strength is dependent on the voltage of the power line and remains relatively stable with the line energized. The higher the voltage on the conductor – the stronger the electrical field around it. For example, a typical overhead distribution line at 11,000V (Volts) and 11m (meters) up in the air will produce average electric field strength beneath the line of (11,000V/11m) approximately 1000V/m. There are other factors affecting measurement, like electrical field decrease with an increase in distance from the line, but example above is just to give general idea of the process involved.

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. For continuous monitoring of the site, 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. These images are available for engineers at a central location to be viewed and structure assessed for any possible damage.

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.

Sensors can be connected to a Neon Remote Logger via SDI 12, Modbus, analog or digital inputs. Logger will scan / collect readings from the sensors on regular, custom specified or intervals. It will check for any unusual out of limits readings and routinely send data to a central Neon Server located at the electricity utility headquarters.

Logged data or alarms are sent using cell phone modem or satellite modem depending on network availability. Data is then displayed on a web browser to be viewed or 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
WXT536 measures barometric pressure, humidity,
precipitation, temperature, wind speed & direction
6501V-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 - NRL / NRT / RTU / Field UnitsUnidata Part NumberDescription
Neon Remote Logger 16 Channels3016AOptions Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa
Neon Remote Logger 8 Channels3008AOptions Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa
Neon Remote Logger 4 Channels3004AOptions Available: 3G/4G Cellular
Neon Remote Logger 4 Channels M Series3004A-MOptions Available: 3G/4G Cellular, Ethernet, Microsatellite, Iridium SBD and LoRa
Cellular RTU 3G/4G2013F-AB03 / 2013F-AB04Neon Metering Module 3G/4G with Antenna and Li Battery
Cellular RTU 3G/4G - Industrial2016F-AB03 / 2016F-AB04Neon Remote Terminal 3G/4G with Antenna and Li Battery
Low Earth Orbit Satellite Globalstar2015F-AB0NRT Satellite Globalstar Modem with Antenna and three Li Batteries
Ethernet2017F-0B0-1 or 3NRT Ethernet with single or triple Ethernet Ports with three Li Batteries
Equatorial Orbit Satellite - Inmarsat2018F-AB0-1 or 3NRT Ethernet with single or triple Ethernet Ports with three Li Batteries
LCD Display2500ENRT LCD Display
NRT Field Termination Strip2103F2015F,2016F,2017F, and 2018F 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
Neon Remote Logger 16 Analog Channels / Touch Screen Display3016A-00016 Ch NRL (Superseded Prologger 7001D)
Neon Remote Logger 8 Analog Channels / Touch Screen Display3008A-0008 Ch NRL (Superseded Stalogger 6004D)
Neon Remote Logger 4 Analog Channels / Touch Screen Display3004A-0004 Ch NRL (Superseded Micrologger 8010C)
Starlog V4 Management Software6308A-AUEStarlog V4 Full Licence Key