SP Energy Networks (SPEN): Development of the Real Time Fault Level Monitor
Having collaborated with SPEN to bring the PM7000 FLM to market we are now working together to produce an active, Real Time Fault Level Monitor that will provide reliable fault level measurements every 10 seconds (selectable). This device will be used to calculate prospective Fault Level Currents at LV or MV, both peak and RMS, incorporating Downstream Contribution, for communication to a SCADA system.
Stage 1 of the NIA (Networks Innovation Allowance) Project is well underway, with 2 RTFLM units already delivered to different SPEN sites (October 2018). These units are being installed and tested to ensure they have as little effect on the network as possible. In the short term they will be connected via distribution transformers and the effect on the network studied.
The latest resutls show the real time change in fault level when switching the number of transformers in a SPEN substation.
Once this testing has been completed at 11kV, Stage 2 of the Project is to install further RTFLMs around the UK. This will be to prove the concept that the results obtained can be used to actively manage the network. As part of the initial project agreement with OFGEM, 3 units were to be made available to each UK DNO to join in Stage 2. Several DNOs have already confirmed their anticipated participation.
Real Time Fault Level Measurement: Impact on the Network
By providing a novel method for identifying additional capacity on networks currently constrained by high (or low) fault levels we hope to see some real benefits to the DNOs/DSOs using our Real Time Fault Level Monitor (RTFLM).
Example: Impact on Customer Interruptions/ Customer Minutes Lost
Exploit accurate up to date network Fault Level knowledge immediately prior to fault-enforced re-routing. Customer Interruptions and Customer Minutes Lost etc. are minimised among other things by making best use of un-faulted resources. Information on Fault Levels around the network immediately prior to a fault occurring can inform decisions regarding the short term remedial strengthening of the network as well as ensuring continued safety as the network operation is restored to normal.
Continually validate network computer Fault Level models. Where computer modelled Fault Level is used to drive routing decisions, real measurements (of Fault Level) can be used to validate the computer models.
Increase re-routing options. A Fault Level Monitor can inform those driving network changes whether the actual prospective fault level is in line with the worst case modelled figure currently assumed. A Real Time FLM value can give accurate, actual, real time prospective fault level values that could be lower than the modelled values if all generation assumed to be on the network is in fact not connected or active. More re-routing options may therefore be made available to those managing the network, creating opportunities for customers to be restored to the grid earlier than might otherwise have been thought possible.
Exploit absent but assumed Generation/Motor Contribution. The inclusion of Downstream Motor Contribution by the RTFLM to yield total prospective fault level will therefore increase flexibility to exploit contingency capacity not only in critical situations but also during normal running of the network. This is particularly relevant where actual Motor Contribution is not well known.
Provide improvements to health and safety through the identification of network conditions pushing fault level close to or over the design rating of substation equipment.
Validate breaker settings. Observe where fault level is significantly higher or lower than calculated, validating breaker settings where either scenario may adversely affect breaker operation (and protection of downstream infrastructure).
Delay/eliminate need for network reinforcement. More flexible and confident management of the network based on actual prospective Fault Level, including downstream contribution, can also potentially delay or remove the need for network reinforcement saving money, avoiding network interruptions for works and reducing the environmental impact of equipment decommissioning.
Maximise breaker life. Where device life, e.g. breaker life, is measured in events at rated fault level, then to know that the actual fault level to which the device might be exposed is less than the rated, can also extend the lifetime of the device.
Initial Fault Level Monitor Development
Innovative Funding Incentive (IFI) scheme from OFGEM
Outram worked with Scottish Power Energy Networks (SPEN) between 2010 and 2014 to design, test and validate the Outram PM7000FLM.
Through deployment of the Outram PM7000FLM in various substations in SPEN’s area, Merseyside and Southern Scotland, John Outram, Lead Designer, was able to get quality feedback on his developing algorithms, information on the necessary parameters to be recorded and help developing the most useful way to present the final fault level data to the user. The project, now completed has been described by SPEN as ‘hugely impressive’.
Results from some of the trials we did with Scottish Power and elsewhere are described in our FLM Trial Results Overview which can be downloaded here.
For more details on the IFI project see page 84 of the Innovation Funding Incentive Annual Report 2012-2013.