The first survey will aim to cover all accessible carriageways in the central London Area. The “centreline distance” of the carriageways is approximately 926km and it is expected that the MAAV will have to drive over 1800km during each assessment. Any object or surface which is energised at more than 1V AC will be recorded and investigated.For each detection the MAAV crew will stop, investigate and collect data on the alarms that were generated. The MAAV software will be updated to display electric field information on the fundamental, second harmonic and third harmonic of the powerline frequency. All data from the investigations will be recorded into a database. A follow-up investigation will be performed at as many identified locations as possible to identify the root cause of the voltage as well as a quantification of the energy losses at each site. The survey will conclude with a report which summarises the findings, data collected and the losses reductions. An analysis of the harmonic information will also be included in the report.The second survey will include the same coverage of the central London area using the MAAV approximately 4 to 6 months following the completion of the first survey. The second survey will identify newly generated contact voltage faults, which will be used to understand the generation rate of these types of faults in the area. The same investigation and reporting process will be followed, except for incorporating any improvements identified from the first survey and report.The data collected will be analysed after each survey to provide a better understanding of the performance, behaviour and health of the central London network. The analysis will include an assessment of the underlying types of faults present, the root causes of the failures and the generation rate of new faults. The impact of proactive elimination of these faults will be assessed at the conclusion of the project along with the energy losses reductions achieved as a part of the programme.

Benefits

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)