Abstract: On site partial discharge (PD) methods have become successful tools to diagnose and monitor cable circuits. This paper describes the background of these methods, some fundamentals and challenges. The first section gives a brief introduction to and definition of the 0.1 Hz or very low frequency (VLF) PD methods. The next section discusses more general items and misconceptions on PD diagnostic testing and its role within condition based maintenance (CBM). The section 'Reflection based 0.1 Hz PD test method' summarises the principle of this method. Finally, the section 'Multi sensor 0.1 Hz PD test method' describes a method to meet the challenge of testing long and branched medium-voltage cables.

Abstract: Knowledge on how wave propagation characteristics and other parameters depend upon cable design is an important base in establishing diagnostic methods for cable insulation. In this study, a shielded medium voltage XLPE cable is investigated and a high frequency based measurement technique is used to measure the properties of the cable material, particularly the semi-conducting screens, in the frequency range 1 kHz to 1 GHz. A materials model is then developed based upon these measurements and this is incorporated into a model for the whole cable. The results are then compared with those obtained from time domain measurements carried out on the XLPE cable.

Abstract: Two approaches are available to detect partial discharge (PD) from power cable insulation-online and offline detection systems. The online system is based on detecting PD at the system operating voltage, while elevated voltages are used to initiate PD in the offline approach. This paper presents the fundamentals of PD measurements. It also discusses the advantages and disadvantages of each approach.

Abstract: The Oak Ridge National Laboratory (ORNL) and the Southwire Company have used the ORNL 5 m cable test facility to develop high-temperature superconducting (HTS) cables and terminations to support the first industrial demonstration of an HTS cable at the Southwire manufacturing complex. Two 5 m, cold dielectric cables have been tested for direct current (DC) voltage, alternating current (AC) losses, AC withstand at 18 kV, thermal-hydraulic performance, heat load, and long-term operation at rated voltage (7.2 kV) and current (1250 A). Two separate termination concepts, one operating at 10/sup -4/-10/sup -5/ mbar vacuum and the other operating with pressurized nitrogen gas at <10 bar, have been developed and tested with the 5-m cables. A 5-m cable has been removed from the facility and bent in a test rig to simulate transport in a spool. A testing program for a third 5-m cable with a splice is in progress. The test program at ORNL has validated the basic design of the cables and terminations and indicated areas for further R&D to optimize this technology for electric utility applications.

Abstract: Power quality is becoming more and more important for electrical utilities. One of the drivers for its improvement is the reduction of the number and duration of outages due to faults on the power distribution cable lines by means of effective condition assessment techniques. Several systems have been made available on the market for this purpose. A wide investigation was carried out in collaboration between Enel Distribuzione and CESI in order to evaluate, through laboratory and on-site tests, the performances of four different medium voltage cable diagnostic systems. The aim of the program was to compare the diagnostic information given by each of the systems under investigation in terms of partial discharge inception voltages, location of PD spots and PD pulse amplitudes. Laboratory tests were carried out on different cables having artificial defects either in joints and in the cables themselves. Tests on site were performed on selected lines of the Italian national network. The paper reports the main results obtained and discusses the criteria for the selection of the most appropriate condition assessment methods for the different types of configurations foreseen in the system.

Abstract: From the point of view of a power utility, insight in the condition of their medium voltage power cable network becomes more and more important to guarantee a reliable and secure power supply. For several years, detection and localisation of partial discharges (PD) using AC voltages is internationally accepted as a symptomatic, reliable diagnostic method for determination of the quality of insulation systems. In this paper, several ageing aspects in medium voltage power cables are discussed, supported by several diagnostic field examples. The following conclusions are drawn: studying fault statistic of components results in the identification of dominant faults; old 'diagnostics' are still very useful for some of these fault causes; using PD diagnostics on cables, important information of a cable section is collected in the PD 'fingerprint' of the measured cable section; standard interpretation rules are used for optimal decision-making for cable repair before failure occurs; the PD inception voltage, PD magnitudes, PD location, PD intensity and PD mapping together can give a good insight in the condition of a cable section; discharge defects can be related to different insulation systems of a cable section, either the cable accessories or the cable insulation itself; from PD mappings important information can be collected concerning PD source types in the paper insulated lead cable, e.g. either concentrated PD or scattered PD; and for determination of PD activity in XLPE cable insulation, combined analysis of PD quantities is necessary.

Abstract: Cable Systems For High And Extra High Voltage Development Manufacture Testing Installation And Operation Of Cables And Their Accessories [Free] Cable Systems For High And Extra High Voltage Development Manufacture Testing Installation And Operation Of Cables And Their Accessories [EPUB] [PDF] We are a global supplier. NKT develops, manufactures and markets high quality power cables, accessories and solutions for the electrical infrastructure, the ... vr, 24 mei 2019 22:06:00 GMT Profile & key figures NKT FORD 2006 ESCAPE HYBRID OWNER'S MANUAL Pdf Download. Industrial Automation in India | PLC SCADA DCS Training in ... We are Chennai based leading company engaged in supplying of electrical and automation systems for various industrial segments. Hindustan Automation Solutions has ... Optical fiber Wikipedia The advantages of optical fiber communication with respect to copper wire systems are: High bandwidth: A single optical fiber can carry over 3,000,000 full-duplex ... FAQs – TMB Who actually is the manufacturer of your Dataplex and ProPlex cables? What is the pin out on DMX cables? What is the voltage rating on your install cables? Suppliers Exhibiting in 2018 | The Utility Supply ... A; ABB Inc. ABB is the world’s leading supplier of power and automation products, systems and service solutions across the power value chain of generation ... USB Wikipedia Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power ... FAQ Schurter SCHURTER offers customer specific solutions, As they are customer specific, there will be a lot of service aspects like, development, puchase, live cycle management ...

Abstract: The set up of nondestructive techniques for measuring space charge has allowed to prove the importance of these charges on the longtime behaviour of cable insulation. It seems today more and more probable that the decrease of performance and breakdown of polyethylene-insulated power cables are related to the appearance and the development of space charges. In this work, we show how one can, using the Thermal Step Method (TSM), to evaluate the electrical state of a significant cable length, both locally and globally. We also compare the charging ability of a cable insulation after two types of applied stress: poling at room temperature and under a thermal gradient similar to the one which appears in cable during operation.

Abstract: Two approaches are available to detect PD from cables, on-line and off-line detection system. During off-line testing, the cable system is normally tested under no-load conditions while the system loading during on-line testing varies depend on the time of testing. For some insulation defects, PD intensity is load dependent. In some other, PD occurs only at certain load conditions. The types of defect that is affected by the cable loading are presented in this paper. Laboratory and field PD data of testing cables at different loading conditions are also presented.

Abstract: An online partial discharge diagnostic system is presented in this paper. The system is capable of detecting a PD event in a power cable system as low as 1 pC. Coupling to the system is made through special sensors that utilize inductive and capacitive coupling. These sensors have a detection bandwidth of 100 kHz to up to 300 MHz. The online PD system indicates location of the insulation anomaly both longitudinally and radially in a cable. Furthermore, the system is applicable to both laminar (PILC) and extruded (PE, XLPE, EPR) cables.

Abstract: In recent years, utilities have had a growing interest in applying PD testing in the existing cable network. The goal of such testing is the detection, location and recognition at an early stage of possible failure in the cable system and accessories. In the cable system, several types of discharges can be classified depending on the defects producing such discharges. This paper describes the types of discharges that normally occur in a power cable and its accessories. The limitations of detecting these discharges by the existing PD test method are also discussed.

Abstract: Condition monitoring in the view of predictive diagnostics and reliability centered maintenance of mass-impregnated cables and other electric equipment gain more and more importance. One of the methods for judgement of the insulation state is the return voltage method. In this paper possibilities and limits of this method for on-site diagnosis to estimate the degradation of mass-impregnated cables are presented and discussed.

Abstract: It has been established that in service aged cable insulation, the polar components are directly related to the presence of water trees in the solid dielectric. R-C combinations, which represent water trees from an equivalent circuit point of view, have different time constants depending on the progression of the water tree. This paper describes an in-situ cable diagnosis method based on measurement of the return voltage. The cable is charged for several minutes by applying a DC high voltage. This step is followed by a soft discharge via a resistor for several seconds. During the third step the return voltage is measured, which results from the discharge of the polar components. The shape of the return voltage curve is characterized by the different time constants. While the applicability of the method seems to be proven in daily practice for PE and XLPE cables, many more tests and the creation of a database are necessary before a final decision regarding the applicability of the return voltage method for paper and PVC cables can be rendered.

Abstract: Over the last five years, DTE Engineering Technologies (USA), a subsidiary of DTE Energy has been involved in conducting online partial discharge (PD) testing on power cable systems operating at voltages from 5 to 138 kV. Online PD testing was performed on 7,500 km of both extruded and laminar power cables. This paper presents the experience gained from these tests.

Abstract: Condition Based Maintenance (CBM) on power cable circuits is an important part of asset management in a liberalised market place for electric energy. Repair before breakdown will be possible after determination of the local condition of the cable circuit. Repair before breakdown reduces the operational costs, increases availability, reliability, trust of customers and postpones investments to a later date. To identify cable weaknesses, cable diagnostics are needed to support CBM. In this paper, the integration of cable diagnostics with CBM will be discussed. Part of this discussion will be the impact of the professionalism of the people performing diagnostic testing on the one hand and the attitude of the network owners asking for diagnostic testing on the other hand.

Abstract: A signal-based cable attenuation measurement device, system and methodology provides measurement of attenuation characteristics of a cable over a wide frequency spectrum. Located at a single location on a cable, a measurement device injects a signal on to the cable under measurement and receives the reflected signal, recording physical characteristics of the cable in response to the signal. A model, calibrated to estimate the effects of the cable with know impedances, evaluates the waveform generated from the cable's response to the signal and computes attenuation of the cable as a function of frequency. In some circumstances, when low signal-to-noise effects result, normally at high frequencies in long cables, the attenuation of the cable is further fitted to the model to correct the errors that occur as a result of the low signal-to-noise effects.

Abstract: Summary form only given, as follows. The Hawk facility at NRL was used to pulse test Dielectric Sciences 2158 cables to voltages in excess of 900 kV. The motivation for the testing was to assess the utility of these cables to connect elements in a high-impedance inductive voltage adder system. A high voltage pulse was launched at both ends of a long length of cable to obtain high voltage by wave adding in the middle of the cable while limiting high-voltage complications at the power feeds to the cables. The pulse width was controlled with a point-plane electron-beam diode. The cables tested were approximately 160' long, with a one-way transit time of 240-ns. A pulse with a risetime less than 240-ns launched into both ends of the cable would add to double the voltage in the middle portion of the cable. The cables were connected to the output of one sub-Marx of the Hawk Marx bank, inside the oil tank. A resistive voltage divider was used to monitor the voltage input to the cable, and Rogowski coils to monitor the current input to each cable end. A point-plane electron-beam diode was also connected to the Marx output. The gap closure associated with this diode was used as timed closing switch to terminate the high voltage portion of the pulse. The stored energy of the Marx was dissipated in the damping resistors that were installed between the Marx and the cable, and the cable and the diode. Four lengths of cable were tested. The cable is designed for use as 69 kV AC power cable. Three of the four cables survived pulses in excess of 900 kV before failing, and the fourth cable failed at over 700 kV. Extensive results of the tests on the 2158 cables are presented.