Embedded Distributed Generation Electronic Fault Current Limiting interrupter
Funding mechanism
Network Innovation Allowance
Duration
Sep 2018 - Mar 2022
Project expenditure
£3.016M
Research area
New Technologies and Commercial Evolution
Regions
South West
South Wales
West Midlands
East Midlands
April 2022
This month the project team have completed the final reporting deliverables. The project is now closed and the closedown report will be published in due course.
This month the project team have completed the final reporting deliverables. The project is now closed and the closedown report will be published in due cour…
Objective(s)
Design an 11kV FCLi for a <=5MW generator.
Manufacture the FCLi.
Perform detailed testing on the manufactured FCLi including Factory Acceptance Testing, external lab testing and ‘soak’ testing.
Complete Internal Arc Testing of a prototype device.
Provide learning and recommendations for the suitability of such a device for implementation in the distribution network.
Problem(s)
The ever increasing penetration of embedded generation coupled with recent improvements in network interconnectivity, have led to rising distribution network fault levels, close to the rated capability of existing equipment which pose several challenges to both DNOs and Independent Power Producers (IPPs). More specifically, new connections are made possible through conventional resource-intensive and often disruptive network reinforcement, with substantial cost and delays to the IPPs which can make these connections unviable. This leaves available generation capacity underutilised, inhibiting the further decarbonisation of the network. In order to enable a scalable and long term path for such connections, the fault current contribution from new generators needs to be reduced to near zero. While some generation sources contribute little fault current (inverter based generation like solar), synchronous ones (such as combined heat and power, CHP) contribute significant fault current.
Method(s)
The project aims to design and test a newly developed solid state Fault Current Limiting Interrupter (FCLi), that can limit the fault current contribution of distributed generators and therefore overcome fault level issues that can limit the network capacity and prevent future connections. The three phase FCLi will be designed for 11kV generator connections ≤5 MW and will be robustly tested to provide learning on the suitability of the technology for implementation in distribution networks. If the complete testing of the device is successful, it will then be trialled within WPD’s 11kV network.
The project is to be delivered collaboratively between WPD and UKPN to ensure that a device is developed to suitably be deployed throughout GB. The project scope is described in more detail below but will consist of collaborative working on the design of the FCLi device as well as factory and laboratory testing to ensure that it is suitable for longer-term testing and site trial.
The project will consist of the following Work Packages:
Device specifications – Specifications will be defined to cover all the device requirements.
Preliminary FCLi design and review – This includes the identification of key components, high level electrical, thermal and control design, and detailed test plan preparation.
Detailed FCLi design and review – This involves full design of all parts including power modules, insulation, control system and operator interface, fault detection system, enclosures, thermal and ventilation detailed design.
FCLi device manufacture.
Testing – The FCLi will undergo a number of rigorous tests including: Factory Testing, Laboratory/Type Testing and Internal Arc Testing.
At this point, if all elements (1-5) have been successful then the following will take place: a. WPD – long term ‘soak’ testing of the device to ensure stability of operation of the device and wider system b. UKPN – register separate NIA project to trial the installation and operation of the FCLi within the 11kV network.
Trial of the FCLi within WPD’s 11kV network where 6a is successful and 6b for a period of six months.
The project will be deemed successful if during the trial period:
The FCLi limits and reduces down to zero before the first peak the fault current contribution of the generator during a network fault.
The FCLi introduces minimal disturbance to the network and the generator during normal operation.
The FCLi remains in normal conduction mode for transient non-fault related events and for faults outside the 11kV network on to which it is connected.
Any device failures are minor and do not render the plant unavailable for more than a few hours.
The knowledge gained through this project will relate to:
The design considerations for the integration of a power electronics (PE) FCLi into a DG connection.
The necessary site preparation works.
The FCLi- Generator compatibility requirements.
The performance and response of the FCLi to real-life network conditions.
The analysis of FCLi performance to identity replicability and suitability for different network topologies.
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