Feb 2013
Electricity Distribution
Modular Rezap Fault Master
Feb 2013
Electricity North West Limited
Electricity North West Innovation Team
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Innovation Funding Incentive
LV & 11kV Networks
The Rezap has proved a real success in the restoration of supplies following transient faults but its size combined with the move to smaller outdoor Low Voltage (LV) feeder pillars means that it will fit into only a limited number of locations. This project collaborated with Kelvatek to redesign the Rezap to fit into all of our current and legacy design LV feeder pillars
Kelvatek has developed a new version of the Rezap with additional beneficial features which is being trialled under separate IFI projects. Further developments are proposed to split the electronic control/power supply and the vacuum bottle with one controller being able to control up to three separate vacuum bottles. This will allow Rezaps to be installed in all outdoor LV cabinets and pillars.


  • Develop and trial a modular Rezap for outdoor substation (for LV transient faults)

  • Develop one controller for 3 modular Rezaps.


  • Compact waterproof (IP rated) case

  • Same features are existing Rezap

  • Specifically design leads

  • Trial a number of modular Rezaps

The initial consideration is to understand the available envelope (that would fit into LV pillar designs) and then to research and specify the proposed modular Rezap by carrying out a feasibility phase which can be used to provide support, with risk quantified and optimised, to improve decision making for capital, operational, design and regulatory issues.