2212 F. P. Mohamed et al.: Partial Discharge Location in Power Cables using a Double Ended Method Based on Time Triggering 1070-9878/13/$25.00 © 2013 IEEE Partial Discharge Location in Power Cables using a Double Ended Method Based on Time Triggering with GPS F. P. Mohamed, W. H. Siew, J. J. Soraghan, S. M. Strachan University of Strathclyde Dept of EEE, Institute for Energy and Environment Glasgow, United Kingdom and J. McWilliam SP Energy Networks, United Kingdom ABSTRACT Partial discharge (PD) diagnostics is the most widely used tool to assess the insulation condition of insulated power cables which facilitates informed maintenance planning leading to extended service life of ageing assets. Time domain reflectometry (TDR) using a single ended or double ended approach is the most widely used method for locating PD sources. The success of the single ended method is dependent upon cable network design. However, by monitoring PDs at both ends of the cable, i.e. double-ended PD monitoring, higher accuracy of PD location can be achieved with a higher success rate. The double ended method is not widely used due to its complex system design, time synchronization and communication requirement between measurement units. This paper proposes a double ended PD location system which triggers on the predefined one pulse per second (1PPS) signal obtained from a global positioning systems (GPS) using novel time based triggering logic (TBTL) implemented in field programmable gate arrays (FPGA). This system ignores non-useable (not synchronized) data caused by flywheel 1PPS from GPS receiver due to any short-term loss of satellite signals which eventually reduces the PD location accuracy. Furthermore TBTL also ignores spurious triggering pulses radiated from noise sources within the substation. With the use of a communication link between two ends of the cable provided via mobile broadband together with TBTL, eliminated the acquisition of non-useable(not synchronized) data. Based on laboratory tests and on-site measurements PD location accuracy of less than ± 10 m can be achieved. The system design, laboratory tests and on-site measurements are discussed. Index Terms — Partial discharges, time domain reflectometry, time synchronization. 1 INTRODUCTION POWER transmission and distribution is achieved using a network of overhead lines and underground cables. Underground cable circuit designs vary in age, voltage and capacity. Much of the existing medium voltage (11 to 33 kV) underground cable network comprises paper insulated, mass impregnated, lead sheathed cables which have been in operation since the latter part of the 19 th century. At this stage, informed condition-based maintenance planning through on-line condition monitoring offers an effective method of avoiding forced outages, thus extends the service life of this ageing asset base and avoiding the need for unaffordable and wholesale cable replacement. The purpose of on-line condition monitoring of cables or any electrical equipment is to predict possible failures before they actually occur. Those assets which are on the verge of failure can then be replaced or repaired, thereby reducing the forced outages. The main business driver in the development of condition based maintenance technologies is the UK regulatory incentive, which requires all electricity utility companies to continuously improve network performance to operate the network more effectively and to reduce operational costs. This necessitates the need for informed condition-based maintenance planning through on-line condition monitoring [1, 2]. Partial discharge (PD) monitoring is the most widely used on-line condition monitoring for insulation integrity assessment of cables. PD induces fast rising pulses appearing as short bursts in the cable core and shield and can be captured using PD Manuscript received on 17 September 2012, in final form 11 July 2013.