A study led by energy specialist Parsons Brinckerhoff has concluded that, under certain circumstances, electrical power lines can carry more than double the amount of electrical energy than their current ‘static’ rating suggests.
The study, which analysed the ‘cooling’ effect of wind on the rating of electrical power lines, has major implications for the wind power industry and particularly wind farms in remote rural locations, where the existing electrical infrastructure is often the limiting factor to the capacity of generation that can be economically connected.
The innovative study was also the recent recipient of a prestigious Institution of Engineering and Technology (IET) Innovation Award 2010, which recognises international innovation in engineering and technology disciplines.
To undertake the 42-month program, PB led a research consortium of Alstom Grid, Durham University, Imass and ScottishPower Energy Networks. The consortium was the beneficiary of UK government funding under the Technology Strategy Board program.
The aim of the study was to develop an approach to help reduce capacity restrictions placed on electricity networks, which can affect connection costs and schedules. The focus was on power systems between 33 kV and 132 kV.
In order to prove the concept, a ‘control system’ was developed and prototyped, which had at its heart a series of software program developed by Durham University and Imass to model the thermal state of the power system.
To test the system, a section of ScottishPower’s 132 kV network in North Wales was chosen for field trials. Since January 2010, electrical, thermal and meteorological data from the trial has been collected by Alstom Grid and processed using the developed thermal state estimation and generator control system software.
Calculations covered real-time ratings of overhead lines, electric cables and power transformers. The results showed that an enhanced knowledge of the thermal state of network components could enhance power flow capabilities. Key findings revealed a potential capacity increase during periods of peak wind farm generation of up to 150 per cent for overhead lines, up to 6 per cent for electric cables and up to 10 per cent for power transformers.
Following the success of the initial trial, ScottishPower would now like to further develop this technology to facilitate the connection of more renewable generation without the need to invest in network infrastructure. A new consortium between Parsons Brinckerhoff, Scottish Power and a number of smart grids equipment suppliers has been formed to drive the technology forward, supported by Ofgem’s Low-Carbon Networks (LCN) funding initiative.
The objective is to implement a real-time thermal rating system across a wide area to give Scottish Power improved visibility of the ‘actual’ thermal operating status of its network.
It will involve the installation of weather stations at numerous sites across North Wales and a centralised network management system, along with overhead line temperature monitoring systems for validation purposes.