On conditionbased maintenance is they key to maintain the correct equipment at the right time. An underground cable essentially consists of one or more conductors covered with suitable insulation and surrounded by a protecting cover. Underground cable maintenance 162 street light maintenance 163. Mobile monitoring of underground cable systems azslide.
Implementation of condition based maintenance for medium. The consequences of ineffective equipment maintenance can be huge in terms of system. Condition based maintenance cbm is an important part of asset management in a liberalised market place for electric energy. Field diagnostic tests can be performed on cable systems during various stages of their operating life. Generally, utilities diagnose the health of a cable based on its age, and they expect cables to last 25 to 30 years. Appreciate the role of regular inspection and conditionbased maintenance in ensuring safe operation gain an insight into the organisational aspects of safety. Figure 3 maintenance overview chart according to en 306 2001. Condition based maintenance cbm is an part of asset management in a liberalised market place for electric energy.
Many utilities have switched to conditionbased maintenance programs to more efficiently spend their capital budgets. Continuous online condition monitoring of hv cable systems. Conditionbased maintenance cbm, shortly described, is maintenance when need arises. Pm can be further subdivided into condition based maintenance and predetermined maintenance which implies that pm can be time based or condition based. The deadfront construction of vfi switchgear improves safety for utility personnel and the general public. Condition based maintenance cbm on power cable circuits is an important part of asset management in a.
The desired attributes for the ideal cable condition monitoring technique are presented along with a general discussion on the various properties of electric cable insulation that can be monitored to assess the condition of an electric cable and the dielectric integrity of cable insulation systems. In particular, cbm is highly effective where safety and reliability is the paramount concern such. Assessment of electrical cable condition monitoring tests sponsored by u. Figure 1 cbm basic structure diagnostics condition assessment maintenance concept condition based. In this paper, uo is defined as the working system voltage between the conductor and. Assessing the condition and remaining life of underground electrical cables first edition december 2016 published by energy institute, london the energy institute is a professional membership body incorporated by royal charter 2003. While a corona discharge cd is usually revealed by a relatively steady glow or brush discharge bd in air, partial discharges. Although a distribution system with underground cables is less maintenance intensive than one with overhead lines, it is necessary to have clear procedures for preventive, corrective and condition based maintenance in order to ensure a long trouble free operational life for the cables. Less voltage drop during normal operating condition and less chance of fault. Knowing the condition of the underground cable system helps ensure reliable operation. As defined by the ieee 400 standard, cable tests are defined as. The interference from external disturbances like storms, lightening, ice, trees etc. With significant challenges facing the electric industry and the world, we are always seeking top talent with handson experience to address issues as they relate to the generation, delivery, use, management and environmental responsibility of global electricity.
The technical committee on inspection, testing, and maintenance of waterbased protection systems notes the following errors in the 2017 edition of nfpa 25, standard for the inspection, testing, and maintenance of waterbased fire protection systems. For serviceaged medium voltage power cable circuits, it is realised by means of. The reliability of underground cable network highly depends upon proper laying of cables, quality of cable joints and branch connections etc. Eatons vfi underground distribution switchgear provides a simple, economical approach to protective requirements for 5, 15, 25, and 35 kv underground systems. It is used when a longer cable is needed or when a part of an old cable is replaced with a new cable. Diagnostic tests used on new and on service aged cable systems. Results of the condition assessment are input for the economical and technical assessment. Implementation of conditionbased maintenance for medium. V underground cable condition assessment project justification report actewagl distribution 4 current situation in the past 5 years, reactive repairs and replacements have been increasing, see figure 1. Albeit chronologically much older, it is considered one section or practice inside the broader and newer predictive maintenance field, where new ai technologies and connectivity abilities are put to action and where the acronym.
A novel approach for prioritizing maintenance of underground cables. Standard for an electrical preventive maintenance epm program page 410 connections. This paper deals with the conditionbased maintenance of singleunit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. Reliability evaluation of underground power cables with. Planned maintenance planned preventive maintenance ppm. Conditionbased maintenance this checks underground power transmission cables and aboveground grid fixtures like joints and terminations that have already experienced partial damage. Standard for an electrical preventive maintenance epm. Those required for a particular system depend on many factors, including the. The best way to gather this information and to guard against failures is to test the cables regularly using proven techniques that reliably indicate condition. Condition based maintenance of mv power cable systems on the. Pdf electrical equipment condition based maintenance. Nevertheless newly installed cables should be pd free up to at least 2.
Tpm framework for underground mobile mining equipment. Determine the injureds condition 263 rescuer 264 tying the injured 264 important 265. On stranded cable, if ends are corroded, cut off ends or separate strands and clean internally. For service aged medium voltage cable circuits it is realised by means of cable diagnostics as part of the condition assessment of the underground cable network. But the main disadvantage of underground cable is its cost of installation.
The linemans and cablemans field manual is written to accompany the linemans and cablemans handbook. This process will determine the asset health, and act only when maintenance is. Results of the condition assessment are input for the. Underground cables are, of course, meant to be installed or laid under the ground. Diagnostic testing of underground cable systems cable diagnostic focused initiative doe award no. What are the maintenance procedures for underground. This relatively new approach to maintenance uses data drawn during operations andor maintenance intervals to forecast the need for additional or future maintenance. Maintenance guidelines for electrical equipment page 1 introduction electric power is the lifeblood of any manufacturing plant or commercial operation.
Most repair work is on the cable joint or termination, and an increasing number of. One of the predominant causes of cable failure is partial discharge pd and collection of pd data can help fill this information gap. The discussion is focused on transmission cables but also has relevance for distribution cable applications. Data acquired by online pd measurements can help in identifying the upcoming faults in such cable networks and possibly forecast the remaining life of the insulation. Pdf condition based maintenance on mv cable circuits as part of. Pdf condition based maintenance cbm is an part of asset. This will give a maintenance concept for cable circuits as part of the total maintenance policy for the network. Online partial discharge assessment and monitoring of mv to ehv. Today, improvements in technology are making it easier to gather, store and analyze data for cbm. Condition based maintenance cbm program for medium voltage underground cables after early application of very low frequency. Either a wideangle global monitoring system or a distributed sensor. A structure similar to a small maintenance hole through which cable can be pulled, but not large enough for a person to fully enter to perform work. Cbm conditionbased maintenance cfr code of federal regulations cmms computerized maintenance management system co2 carbon dioxide dc direct current epss emergency power supply systems fist facilities instructions, standards, and techniques hecp hazardous energy control program hz hertz jha job hazard analysis mawp maximum allowable working.
Standard for the inspection, testing, and maintenance of. However, because of the general high reliability of electrical systems and the fact that deterioration in these systems is often silent and hidden. Details of the construction of the cables and major accessories for each of these cable systems. Introduction increasingly, utilities, developers and power. These tests are intended to detect any manufacturing, transport, and. Conducted after the cable is installed but before any accessories jointssplices and terminations are installed. For higher voltage the cost of cable increases due to greater requirement of insulation as. Pdf online partial discharge assessment and monitoring. High voltage xlpe cable systems technical user guide. Under ground cables presention linkedin slideshare. The diagnostic capabilities of predictive maintenance technologies have increased in recent years with advances made in sensor technologies. It is less liable to damage during storm or bad whether condition. A vault located in the ground or earth as part of an underground conduit system and used to facilitate placing, connectorization, and.
Cable joints, which are part of the underground cables, can also cause outages in the network. It helps to predict when and what kind of repairs might be needed in the future, or if faulty sections need immediate replacement. Work on underground cable systems use and upkeep of safety appliances in. Traditional asset management approachesissueslimitations 2. Underground system design tadp 547 gonzaga university. The aim of planned maintenance is to reduce downtime by having all necessary resources on hand, such as labour and parts, and a strategy to use these resources. The alternative to a timebased maintenance program includes a conditionbased maintenance program or a reliabilitycentered maintenance rcm based program that may justify longer or shorter time intervals. Evolution of maintenance practices past present future. Pdf condition based maintenance on mv cable circuits as. Without proper maintenance cables can still operate well for many years.
Service life of electrical cable and condition monitoring. Figure f2 cable feed into conduit at floor level c from cable reel to cable tray, the cable is fed from the top of the reel to maintain required curvature. Vfi underground distribution switchgear cooper industries. Assessing the condition and remaining life of underground. For this the utilities and the regulations of each country are developing test criteria for the commission and maintenance of cable systems. Planned maintenance refers to any maintenance activity that is planned, documented, and scheduled. Of all the major asset classes, underground cables often have the least available condition data but at the same time have a significant impact on network performance. To confirm the adequacy of condition monitoring under normal operational and loca conditions to confirm the conditionbased qualification methodology. The jointing is the act of reconstructing two cables to become one.
Utility proactively tests underground cable electricity. Condition based maintenance cbm offers the promise of enhancing the effectiveness of maintenance programs in a way that no other single concept has ever matched. Facilities instructions, standards, and techniques volume. This monitoring system does not require a power supply at the site of the cable joints and hence may find wide application for.
Condition based maintenance on mv cable circuits as part. There are three main methods of laying underground cables, which are i direct laying, ii drawin system and iii. On condition maintenance is based on using realtime data to prioritise and optimise maintenance resources. A joint is usually the weakest part of an underground cable and it is affected by. Remove any corrosion on battery terminals with bicarbonate of soda. Epri is at the center of a quickly evolving energy landscape. The development of high voltage xlpe cable systems goes back to the since then production and material technology have improved significantly, providing reliable and maintenance free products to the utility industry. This paper provides an introduction to the cable system types and presents an overview into considerations for using underground cable systems. Conditionbased maintenance allows preventive and corrective actions to be scheduled at the optimal time, thus reducing the total cost of ownership. In electrical engineering, partial discharge pd is a localized dielectric breakdown db which does not completely bridge the space between the two conductors of a small portion of a solid or fluid electrical insulation ei system under high voltage hv stress. The cable is fed from the bottom of the reel so that its curvature is continuous with no reversed bends. Predictive maintenance attempts to detect the onset of a degradation mechanism with the goal of correcting that degradation prior to signiicant deterioration in the component or equipment. Partial discharge pd monitoring is one of the successful diagnostic tools for accessing the insulation condition of mv cables.
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