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Reference Number NIA_ENWL012
Title Investigation of Switchgear Ratings
Status Completed
Energy Categories OTHER POWER and STORAGE TECHNOLOGIES(Electricity transmission and distribution) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
Electricity North West Limited
Award Type Network Innovation Allowance
Funding Source ENA Smarter Networks
Start Date 01 December 2015
End Date 01 December 2016
Duration 12 months
Total Grant Value £300,000
Industrial Sectors Power
Region North West
Programme Network Innovation Allowance
 
Investigators Principal Investigator Project Contact , Electricity North West Limited (100.000%)
Web Site http://www.smarternetworks.org/project/NIA_ENWL012
Objectives 1. Carry out a series of investigative short circuit tests at an independent test station on a range of commonly used distribution switchgear and publish revised fault level ratings where appropriate. 2. Calculate the actual fault level at distribution substations and the level of typical attenuation. 3. Assess the available fault level headroom. 4. Publish a report outlining the details of the investigations and the potential for application of revised ratings. 1. Completion of the short circuit tests and reports. 2. Table of actual fault levels at distribution substations3. Table of actual fault level headroom.
Abstract Historically DNO networks are designed to cater for unidirectional power flow, predictable fault current paths and predictable fault current levels. Due to government CO2 targets there is an increasing amount of generation being connected to the network at all voltage levels resulting in bidirectional power flows, unpredictable fault current paths and higher fault current levels. These generators provide an additional infeed to the network and under fault conditions this infeed will contribute to the level of fault current causing an increase which in some conditions may be quite significant. This results in more areas of the network running close to or possibly beyond the designed fault current rating. Existing innovation projects, including the Electricity North West Second Tier Project Respond, are investigating methods of controlling this fault level and are particularly focussed on the 11kV primary substation circuit breakers. Network operators have a significant population of 11kV (and other high voltage) distribution switchgear such as Ring Main Units etc which will be expected to carry this increased fault current without damage. This equipment has a manufacturer’s assigned rating which declares the level of current it can safely carry for 3 seconds. In practice equipment will only be exposed to fault currents for a much shorter period of time owing to fast operation of protection to clear the fault. Further it is important to note that the fault current diminishes the further away from the primary substation source. Given these factors it would be beneficial to calculate the fault level headroom based on the equipment location on the network and the local protection operating times. As part of the preparation work for Respond Electricity North West tested a small sample of the distribution switchgear population which successfully demonstrated its capability to carry this increased fault currents for a shorter period of time. Building on this earlier work it is the intention of this project to develop a short circuit (fault withstand) performance "envelope" for a range of the more commonly used distribution switchgear variants. This will allow "tailored" replacement decisions based on the actual fault levels at the equipment location and the actual capability of the equipment. This project will conduct a series of investigative short circuit tests at an independent testing station to create a short circuit performance "envelope" detailing maximum levels of current at a range of times up to 3 seconds on a range of distribution switchgear. The fault level performance levels will be further informed by the age and condition of the equipment. Electricity North West will use standard fault level calculation software to understand the actual fault level the distribution switchgear will be exposed to. From the tests and the fault level calculations Electricity North West will then be able to assess the correct Fault Level headroom and target the fault level reinforcement programme more effectively.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications (none)
Final Report (none)
Added to Database 21/08/18