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Reference Number NIA_UKPN0020
Title Mobile Asset Assessment Vehicle (MAAV)
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
UK Power Networks
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 July 2016
End Date 01 January 2018
Duration 18 months
Total Grant Value £544,322
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
 
Investigators Principal Investigator Project Contact , UK Power Networks (100.000%)
Web Site http://www.smarternetworks.org/project/NIA_UKPN0020
Objectives The aims of the project are: Understand the suitability of MAAV (or similar) for assessing UK urban electricity networks Improve the safety and reliability of the LV network To understand the frequency at which LV faults manifest themselves as contact voltage faults Confirm that a strong correlation exists between contact voltages and LV cable faults Collect detailed information about the faults and their electrical properties Determine the generation rate of new faults Upon completion of the survey contact voltage fault locations in central London will have been identified, analysed and repaired and the failure rate of the system will be better understood. The primary success of the survey will be the proactive elimination of faults which will enhance public safety and network reliability. Additional value will be created by the analysis of the underlying faults and the quantification of the energy losses. The project will be successful if the following outcomes are achieved: A determination of the generation rate of contact voltages per mile of survey which can be used to better understand the cost and benefits on a larger scale deployment (from completion of the first survey and assessments)Documentation of the nature and behaviour of the faults that have generated contact voltage hazards A greater understanding of the electrical properties of the contact voltage faults An estimation of the generation rate of new fault, which in turn can be used to optimise future survey frequency (from completion of the second survey and assessments)
Abstract The UK Power Networks’ electricity distribution network is comprised of more than 89,446 km of underground Low Voltage (LV) cables. These cables form the backbone of the network connecting supply to customers’ properties and street furniture. Faults on LV cables are difficult to detect and locate and are responsible for significant numbers of customer interruptions and customer minutes lost. The fault impedances are generally high allowing the faults to exist for extended periods without operating protective fuses. As the environmental conditions around the faults change the fault impedances also change and some evolve into low impedance faults with high currents which result in fuse operations. These underground faults are difficult and costly to locate since they are not visible from the surface and often require extended trenching to expose and identify the fault. These faults also place the public at risk of an electric shock when they come into contact with a surface or object which has become energised by one of these faults. Two examples from January 2016 include a dog which was shocked by a failed LV cable in East Grinstead and a member of the public who was shocked by a council owned lighting column in Portsmouth. In the UK there is currently no consolidated reporting system for documenting electric shocks to the public and as a result these events are not well understood or documented. In the USA where such systems are in place utilities have documented significant reductions in public shock events. Consolidated Edison in New York has reported an 84% reduction in electric shocks over the first three years of their program. In 2012 UK Power Networks hired the SVD-2000 to perform a survey of the LV network around the 2012 Olympics venues. Since that time the technology, process and understanding of contact voltage testing have advanced significantly. In July of 2016 the Institute of Electronic and Electrical Engineers (IEEE) published the first peer reviewed standard on the topic. That standard contains a number of newly document processes that were not available at the time of the 2012 survey. The proposed survey will also include measurement and post-detection analysis process that were not available in 2012. For example, during measurements in this survey the harmonic content of the voltage waveform will be collected and analysed. That information provides critical clues about the underlying source of the voltage, thus allowing faults with equal voltages to be addressed based on their risk to the system and public. The MAAV is a very sensitive mobile electric field detector which will survey the carriageways in search of faults from the LV network. When a fault is detected the technicians will exit the vehicle and use handheld test equipment to pinpoint the location of the fault as well as an acceptable ground reference location for use in the measurement. Fault data, including voltage, harmonic content, location and weather data will be collected. The data will be recorded using a laptop computer in the vehicle and stored in a database for analysis. UK Power Networks will own all data that is collected during this project. It is assumed that each detection of voltage leakage will represent an LV fault on the network. The MAAV aims to proactively identify and prioritise for repair as many LV faults as possible, thereby allowing an early intervention for a planned replacement of LV faultin an efficient fashion. The survey will generate a list of sites where voltage has been detected and measured. This data will be used along with LV network maps and other operational data to determine which sites are candidates for excavation and repair. The repairs will generate additional data about the underlying fault, the root cause of the failure and the amount of energy lost due to the fault. All of this data will be compiled and analysed as a part of the reporting and analysis phase of the project at the conclusion of each survey. A second complete survey will be carried out which will provide data critical to the understanding of the failure rate of the system. It will allow for the measurement of new faults that were formed in the time between the two surveys. A business case analysis comparing targeted MAAV driven cable replacement, proactive traditional cable replacement and reactive replacement will be a part of the second report. The proactive detection and location of faults offers several benefits over the business as usual case. Fault locations identified by the MAAV are generally very accurate determinations of the location of the fault, allowing for efficient excavation and rectification of the underlying problem. Using new measurement methodologies, the data collected during the initial measurement process by the MAAV team provides important details about the nature of the underlying fault. That data, combined with operational and geospatial data, such as network maps, allows for the prioritisation of repairs in a manner that was previously not possible. Using the prioritised listing of faults operational teams will be able to target the response to these weak points in the LV network and make proactive repairs, before they impact customers, in a highly targeted and capital efficient manner. By mending weak spots in the network the risk of cascading failures is minimised. Each energised location also poses a potential risk of electric shock to the public, the proactive identification and elimination of these faults reduces the risk of electric shock to the public. The MAAV will also be equipped with new analytical tools. Real-time displays of the harmonic content at various frequencies are under development for this survey. That information aims to enhance the sensitivity of the system to arcing LV faults. There is potential that these faults could be better located and characterised by recording and analysing information at the second and third harmonic. Currently utilities in the USA that have implemented similar systems only rely on data at their baseband operating frequency of 60Hz. As well as using baseband 50 Hz sensors; software, sensors and data collection will be implemented at 100Hz and 150Hz during this project to determine if further process refinements are possible.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
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Final Report (none)
Added to Database 14/09/18