Fault Level MonitorObjective

The safety of the transmission and distribution networks depend on circuit breakers that interruptthe supply to affected sections of the grid in thecase of a fault. The infrastructure must withstandthe currents that flow during the period before thebreakers isolate the circuit to prevent destructive failure.Knowing this fault current is essential to ensure safety, optimise investment in infrastructure and ensure optimal operation.

Under this Innovation Funding Initiative (IFI) project, Outram Research and SP Energy Networks are working together to develop, test and validate an entirely original, commerciallyviable solution to determine the peak fault current at anyvoltage level by observing natural disturbances on thenetwork during normal operation.

What We Are Doing / Solution

Over the last two years SP Energy Networks and Outram Research Limitedhave been working closely to develop a new algorithm to measure faultcurrent and have implemented this algorithm on the existing OutramPM7000 hardware platform.

Following on from successful lab trial results the Outram Fault Level Monitor(FLM) has been taken to field trial with SP Energy Networks deploying several FLMs at different points of the network in England and Scotland.The results achieved have been very encouraging and consistently within5% of the values produced by advanced models, which is hugely impressive considering that this is from current disturbances that introduce voltage disturbances of as little as 0.2%.

The remaining time on the project will be spent validating the FLMs resultsand the fine tuning of the algorithm and user interface.

Benefits

The fault level monitor has two immediate uses to Distribution Network Operators:

I. To validate and refine existing system analytical models by obtaining visibility of actual system fault levels and contributions from customer equipment under a wide range of real-world scenarios

II. The identification of the fault level in areas of network where network modelling may be difficult or problematic, e.g. sections of the 11kV or Low Voltage network.

The potential benefits associated with the above are as follows:

• The Health and Safety benefits of identifying and subsequently managing fault level issues which were previously unknown due to inaccurate or non-existent models.

• Operational benefits that are gained from the ability for optimal operation or interconnection of the network which could be restricted due to a perceived fault level issue.

• Financial rewards associated with an improved Regulatory Performance rectifying fault level issues, e.g. removal of perceived fault level issues by accurate monitoring as opposed to conventional equipment-based solutions.

• New Connection – the benefits associated with facilitating new network connections which previously may have been problematic or financially prohibitive due to modelling, scenario and data inaccuracies.

• Environmental benefits associated with the connection of renewable generation as detailed above and the moth-balling of equipment ahead of its end of life due to fault level upgrades.

• Further Innovation – up until now there has been no readily available and deployable device for fault level measurement, as this device becomes adopted there is huge potential for its integration and expansion into network operations, e.g. as part of an Active Network Management scheme.

spenergynetworks.com/innovationSPInnovation@spenergynetworks.com