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Projects: Projects for Investigator
Reference Number NIA_NGTO014
Title Advanced Line Rating Analysis (ALiRA)
Status Completed
Energy Categories Other Power and Storage Technologies(Electricity transmission and distribution) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 80%;
ENVIRONMENTAL SCIENCES (Earth Systems and Environmental Sciences) 20%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
National Grid Electricity Transmission
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 July 2018
End Date 01 July 2020
Duration ENA months
Total Grant Value £301,790
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , National Grid Electricity Transmission (100.000%)
  Industrial Collaborator Project Contact , National Grid plc (0.000%)
Web Site https://smarter.energynetworks.org/projects/NIA_NGTO014
Objectives This project will consider the whole of NGETs transmission network (overhead lines only) and assess the variation of thermal ratings between routes throughout England and Wales. The project will also assess the variation of thermal ratings between spans along individual routes.Climate and terrain models will use historic weather data, recorded from points around the UK, to generate up to 10 year weather history for every OHL span on the NGET Transmission System. This weather data will be calibrated against measured data recorded from NGET overhead line towers. Weather data generated will include Ambient Temperature, Solar Radiation, Wind Speed and Wind Direction.The generated weather data will enable overhead line temperatures to be calculated at regular frequencies throughout the 10 year period. The variation of calculated conductor temperatures over this period can be assessed and the risk associated with exceeding current operating temperatures can be calculated. Understanding how the risk varies throughout the country will provide a framework and a measure for applying enhanced ratings to certain routes.Due to the complexity of the model used, and the potential run time, two conductor types will be used to calculate conductor temperatures for all routes. High resolution models will be applied in two different areas of the country (where the frequency of the weather data will be increased). This will allow us to determine whether the resolution of the data is suitably accurate. In addition, all conductor types will be analysed for a subset of routes (circa 500 spans) in each of the high resolution domains to determine whether the conductor type is significant in determining line ratings.At the start of the project, an optimisation exercise will assess the effects of data resolution on model run time. This will ensure that the quality of the data output by the model is acceptable whilst maintaining reasonable timescales for the overall project.National Grid will provide the supplier with the following information: Tower/route location data, Weather data recorded from OHL towers, OHL Rating algorithm, Conductor details, Thermal rating test scenarios. The stages of the project will be performed as shown below:Milestone 1 Tower data, conductor data, weather data, the ratings algorithm provided by National Grid Milestone 2 Installation and successful validation of National Grids line rating model. The available weather data and routes in scope will be reviewed to select initial region(s) for testing. The optimum amount of weather data needed to generate reliable line rating data will be determined. Milestone 3Summary Report detailing findings from data audit, weather simulation and overall results of data optimisation exercise. Long term weather data will be generated for the routes in scope. This will be compared with available weather station data. The weather data will be used as inputs to National Grids line rating calculation code. This will be used to calculate line ratings for each span of each route in scope. The output at this stage will be a time series of line ratings for each span. Weather sensitivity analysis will be conducted to assess the impact of weather simulation errors on the final results. This will allow suitable safety factors to be included in the new line ratings. Statistical analysis will be used on the time series to calculate a line rating that is suitable for the entirety of each route in scope. This will account for the lowest rated span in each route. Probabilities of exceedances for each span in each route will also be presented. Data analytics (e.g. clustering analysis) will be conducted on the larger data set to identify geographical or seasonal patterns. The above analysis will be conducted with two simulation setups in order to be efficient with respect to storage space and code runtimes. New static line ratings for each route in scope on a span-by-span basis and a route-by route basis. New static line ratings will be analysed for geographical and seasonal patterns (i.e. can any new rules for static line ratings be applied on a regional or seasonal basis). Information that enables NGET to calculate new static line ratings will be provided along with a probability of exceedance. This will give a better understanding of existing thermal ratings and where higher ratings may be appropriate. A comparison of the line rating results generated using medium and high resolution weather data. A comparison of the line rating results from different conductor types using high resolution weather data. Milestone 4Generation of data that allows NGET to calculate new static line ratings and probabilities of exceedance for medium and high resolution zones. Analysis of the impacts of weather resolution and conductor types on line ratings.Data and Report provided to National Grid. Data provided will be time series data for each span and will include the weather parameter data and the calculated conductor temperatures for all scenarios. Any relevant geographical or seasonal patterns. E.g. if all line ratings within a particular region are similar within a tolerance, this will be identified. Summary Report provided to National Grid detailing geographical and seasonal analysis. To reduce the need for load related investment in locations where higher thermal ratings are available due to favourable weather conditions. The scale of this reduction will be determined by the extent to which weather conditions vary dependent on geographical location.
Abstract Current overhead line (OHL) ratings are applied on a seasonal basis and do not consider the geographical location of the assets and associated variances in meteorological conditions. As such, line ratings may be unnecessarily constrained, limiting power flows and prompting unnecessary investment for load related upgrades.
Publications (none)
Final Report (none)
Added to Database 09/11/22