Dynamic line rating

1
Dynamic line rating

• Jeremy Colandairaj

2
Outline

• Factors affecting line ratings
• NIE dynamic line rating project
• Current weather measurement
• Project milestones
• Analysis
• Concluding remarks

3
Factors affecting line ratings

• Wind speed and direction
• Ambient temperature
• Precipitation and humidity
• Solar radiation
• Line construction (materials)
• In order to accurately rate a line, constant
  monitoring of the temperature of the conductor is
  required

4
NIE dynamic line rating project

• Jointly developed by NIE and FMC-Tech
• Jointly funded by NIE and wind farm developers
• Objective
• Measure line current and weather conditions
• Investigate correlation between weather
  conditions and line ratings
• Develop real-time dynamic line rating
• Publish methodology and results

5
Current weather measurement

• FMC-Tech have previously developed a self-powered
  overhead line sensor (line current)
• Additional development is required to measure
  surface conductor temperature and weather data
• Wind speed and direction
• Ambient temperature
• Solar radiation
• Precipitation and humidity

6
Real-time monitoring procedure

• Line loading and weather data are communicated by
  wireless (868MHz) to a nearby controller (lt250M
  distance)
• The controller forwards the data via GPRS to
  FMC-Techs server
• Data is displayed through the Web-Controller
  which is assessable via the internet

7
Real-time monitoring procedure
Modified MV Sensors to measure line temperature.
Diagram courtesy of FMC-Tech
8
Line selection location of measuring equipment

• Line selection
• Planned one set on 110kV and 33kV lines each
• Dungannon-Omagh circuits (110kV)
• critical to wind farm output
• Overload above 300MW wind in NI
• Delays on 33kV due to difficulty in placing
  equipment
• Location of measuring equipment
• (determined by desktop survey)
• Wind noisy areas
• Wind quiet areas

9
Project milestones

• Development of Web-Controller (March 07)
• Factory acceptance test (April 07)
• Site acceptance test (August 07)
• Test at 20kV completed
• Risk to progress low
• Installation and commissioning of all equipment
  (September 07)
• Risk to progress for 110kV low, 33kV medium
• Project report and analysis (May 08)

10
Progress to date

• Development of hardware and software is nearly
  complete
• Sensors and weather station are currently under
  HV testing
• Next stage is installation on NIE network
• Project is currently on time and on budget

11
Analysis

• Researched within NIE by year out Engineering
  student under supervision (Dr. Colandairaj)
• Objectives
• Determine correlation between weather conditions
  and line rating
• Develop methodology for dynamic line rating
• Implement in simulation and compare against
  static and seasonal ratings
• Time permitting Forecast ratings based on
  extrapolation from historical measurement data /
  prediction (e.g. Anemos)
• Report methodology and results

12
Standing questions to be resolved in analysis

• Is there correlation between power generation at
  wind farms and wind cooling on overhead lines?
• How do weather conditions compare with fixed
  installations (e.g. Belfast Aldergrove)?
• Are there critical spans and if so, what are the
  factors influencing their location?
• What is the affect of altitude?
• Wind cooling
• Solar radiation

13
Concluding remarks

• NIE has committed, together with wind farm
  developers, substantial resources to determine
  the feasibility of dynamic line ratings
• Work is currently progressing on time and on
  budget
• Installation on 110kV line - September 07
• Possible issues with 33kV installations