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Projects: Projects for Investigator
Reference Number NIA_NGET0112
Title Enhanced AC and DC safety voltage limits assessment
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
National Grid Electricity Transmission
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 October 2013
End Date 01 October 2015
Duration 24 months
Total Grant Value £253,948
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , National Grid Electricity Transmission (100.000%)
Web Site http://www.smarternetworks.org/project/NIA_NGET0112
Objectives There are three main objectives that this project is aiming to deliver, with one stretching objective. These are (in no particular order) to produce a standard for ground surfaces in terms of earthing of an AC/DC system. Secondly, to quantify the existing electrical performance of commonly used substation materials. Lastly, to develop a piece of software that calculates and quantify these safety voltage limits. The stretch target for this project is to make the standard internationally acceptable throughout the electrical community. The research being done in this project will aim to quantify the electrical resistance of ground surfaces currently installed on the network, and then provide a calculating tool that can produce safety criteria under AC & DC conditions, a variety of site use scenarios and a realistic range of surfacing materials. The project will be successful if, at the end of the project, we have the tool for quantifying the electrical resistance of the ground surface, a dataset of common materials, and a recommendation for changes that are needed to the National Grid policy document.
Abstract In the power system, an electrical fault is any abnormal electric current for example, a short circuit is a fault in which the current bypasses the normal route. In the event of a fault, the system is connected to a mesh under the substation floor. This enables the fault to travel to earth. The electrical resistivity of the surface material above the mesh and below your feet is a safety consideration when we design a substation. The safety publication IEC 60479-1 details the effects of current on human beings and livestock ranging from an electrical frequency of 10 Hz to 100 Hz. The transmission system is operated at 50 Hz, so this IEC document is the standard to base our findings on. It details what level of current experienced by the body gives different effects - no effect, mild discomfort through to death. Currently, there is not a national or international standard on earthing of HVDC systems that addresses the electrical resistivity of surface materials. This is problematic to National Grid due to the amount of future HVDC systems that will be connected to our AC system, and the type of effect that an AC/DC interaction can bring on to the earthing systems. RESEARCH This project is going to develop a standard for which substation ground materials are installed based on their electrical resistivity. This standard will then be issued to contractors doing the works on site, and we can ensure an appropriately costed surface can be installed, that still ensures the safety of workers on and around the HVDC systems. The method proposed by Cardiff University involves a Literature survey of existing material, Computer simulation and software development of a calculating tool, and Lab tests of materials to provide the parameters for the software to reference. The lab testing and computer simulation are logical processes to follow also. The lab tests will involve taking standard surfaces (such as aggregates, tarmacs etc) and applying electrical current to them, measuring the resistance they impose on the electricity. This range of values will then be input into computer software to be developed as part of the project, in order to visualize the data and make it user friendly.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 14/08/18