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Please follow the links to view the publication.Modelling of spring type electrical contacts
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0635
This study deals with the characterisation of the electrical contacts used in GIS applications (permanent current flow), both by numerical calculation and experimental testing. The good behavior of an electrical contact is related not only to the choice of the materials but also to its geometry. The optimization of these factors will ensure a good performance of the product. This study shows the influence of materials and geometrical parameters on mechanical force and electrical resistance of the contacts. So, the study will allow the optimization of the contact in order to ensure high performance and a stable contact resistance in time.Study on the reliability test of automotive relays under temperature cycling condition
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0623
Automotive relays are the important control components in vehicle electrical system. Temperature is one of important factors in reliable operation of automotive relays. Based on the analysis on failure modes of automotive relays at high and low temperature and under temperature cycling condition, this paper introduces reliability indexes and proposes one test plan of the reliability compliance test for automotive relays under temperature cycling condition. The reliability test was carried out and the failure analysis on the typical failure samples was presented.Test stand for testing contacts of switches in a fixed household electrical installations
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0642
Description of a computerized test stand designated for switching testing of contacts in switches used in fixed household and similar installations. Testing device has a mechanical drive, adapted for testing of key-driven (actuator) switches, and an electronic measurement system adapted for simultaneous testing of 5 switches. The stand's software enables to execute the statistical measurements of different electrical and mechanical quantities during testing of the switching ability. Current and voltage waveforms are recorded in the computer's memory and after the test they may be analysed and described in detail. The measuring system enables to designate the number, duration and arc energy of the contacts' bounces during switching on and arc duration and energy during switching the current off. Readings are then tabulated and may be presented in the graphical form.A correlation of silver tin indium oxide-copper composite rivet interface bond quality and switching endurance life in DC relays
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0644
This work investigates contact life as a function of the contact internal interface bond quality. The comparison is made using resistive load under different DC power voltages and currents for different designs of composite rivets with different bond and silver metal oxide (AgMO) thickness. It demonstrates that the rivet bond is a predominant factor to contact life for higher switching power levels and less at lower powerlevels. A mechanism for contact interface bond deterioration is discussed in terms of contact surface melting, bond interface temperature, arc energy and AgMO layer thickness.A 'Universal' life-test system for electromechanical relays
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0632
The field of Electrical Contact Switching brings together physics, material technology and accumulated experience and remains a very analogue science. Real-world monitoring of contact switching is vital in determining the best materials and construction for a relay device and to ensure quality in today's demanding market place. Although it is simple in principle to cycle a relay with a specific contact load and observe total failure, designers today require much more insight into trends allowing them to better predict failures in contact use, in application areas that have not been fully tested. Applied Relay Testing has been performing research and development into a `universal life test system' which would provide information about contact voltage and current, contact timing and device operate / release voltage actually DURING the lifetest, showing each of these parameters in a graphical form and allowing their trends to be observed. This paper will describe the measurement techniques involved and the results obtained, illustrating how this test system brings a unique insight into the life-time of the modern electromechanical relay.Latest on-air testing of U.S. MIL-STD-188-110C Appendix D wideband HF data waveforms
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0386
The US MIL-STD-188-110B has been revised to MIL-STD- 188-110C and includes Appendix D defining a family of wideband HF data waveforms supporting bandwidths from 3 kHz to 24 kHz in increments of 3 kHz. This waveform family, designed by engineers at Harris Corporation and Rockwell Collins, extends the high performance serial tone modem technology of the original versions of the standard to wider bandwidths. The wider bandwidths can provide user bit rates up to 120 kbps and allow users the option of selecting the bandwidth and modulation so as to optimize modem performance. This paper provides an overview of the newly standardized wideband HF waveforms and reports on a series of recent on- air tests performed to evaluate the tradeoffs required to utilize the new waveform standard as the basis for a high performance adaptive HF system. Results are presented for recent on-air testing over several different HF links. These include a 160 km Near Vertical Incidence Skywave (NVIS) link, which is representative of common tactical military HF communications scenarios, and a 1,700 km skywave link more representative of a strategic back haul link. Additionally the latest series of on air testing, reported in this paper, specifically addresses the robustness tradeoffs offered by the new suite of wideband waveforms. (5 pages)A novel method for illumination and communication using white LED lights
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0149
LED lighting is regarded as the most potential lighting source due to its advantages, such as low power and long lifespan which is largely dependent on the temperature of the LED. So it is possible to predict the life of the LED lamp if the temperature can be read. The conventional method of reading information about a LED lamp is based on communication buses such as RS485 and CAN, but it is inconvenient to add communication lines. This paper proposes a novel compact lighting system which integrates the communication function into the conventional LED driving. Switching frequency modulation method is applied in the system so as to modulate data in the visible light. And the design of the receiver is also proposed, which identifies different frequencies and demodulate data. The introduced system achieves control over communication and dimmer independently at the same time. An experimental system is developed to demonstrate the effectiveness of the proposed approach. (5 pages)Enhancing differential protection stability during CT saturation with transient bias
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0036
The paper describes a Transient Bias technique designed to overcome the effects of Current Transformer (CT) saturation, which might severely affect the behaviour of a protection system. This Transient Biasing, as the name implies, is only active during transient conditions in the power system, and it decays quickly once the transients disappear. A complementary algorithm for fast detection of external faults is proposed, which prevents the Transient Bias feature from increasing the differential protection operating time in case of internal faults. The operation of current differential protection with Transient Bias is checked using Simulink<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">®</sup> models of the relay and current transformer. In addition, the paper reviews the results of RTDS<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">®</sup> tests carried out with actual current differential relays and provides detailed information on CT requirements testing method adopted by Alstom Grid. (4 pages)Assessment of transformer relay algorithms and settings in laboratory using transient simulation data
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0017
This paper presents an analysis of the main operating conditions that may lead to inappropriate differential protection operation. These conditions were simulated using the Alternative Transients Program (ATP) and the model of a real system. The saturable transformer was the main component of the ATP/EMTP simulations. The saturation and hysteresis effects are represented by a non-linear model of the magnetizing inductance. The results of several ATP/EMTP simulations of normal and fault conditions were converted into COMTRADE format files. These files were used to verify the performance of relays in low-voltage laboratory tests, using various relay settings. (6 pages)Why cable cleats are vitally important in the protection of a cable installation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0528
Summary form only given. Amongst the plethora of theory, standards and literature regarding fault protection, and arguably amongst the immediate understanding of the term 'fault protection', very little attention is given to a crucial piece of equipment in a power cable installation the cable cleat. Very often attention is given to other 'cable accessories' such as joints, glands and terminations, but often the cable cleat is overlooked and left until the end of the installation process where it is included in the 'bulk' call off for consumables or general fittings. Most engineers recognise the importance of topics such as circuit design and layout, fuses, circuit breakers and the like, and these issues are undoubtedly essential. However, the engineer often overlooks the fact that the timing of an 'typical' breaker is approximately 3-5 cycles, or 0.06 0.1 seconds on a 50 Hz system (an exceptionally quick relay may operate at 1.5 cycles). However, if one considers a phase to phase fault, and we look at the highest and most destructive forces i.e. at the peak of the fault, we need to consider a time point of a quarter of a cycle i.e. 0.005 seconds. The intention of this paper is to underline the necessity of providing a cleating solution which ensures that the electro-mechanical forces are restrained and the power cables remain in position for long enough to allow circuit breakers to act and arrest the fault. A comprehensive description of the testing which is necessary to conform to the appropriate legislation will be given. Discussion will focus on different types of power cable construction and various fault levels. Preliminary in-house testing will be discussed and also specialised 'live' short circuit testing which is carried out in the Netherlands. The paper includes photographs taken from these tests which demonstrate the immense force involved during a fault and clearly show the damage to a cable installation if it is not properly cleated. A common perception is that steel wire armoured multi-core cable withstands the internal bursting forces of a short circuit. Mathematical reasoning for this perception is demonstrated, including temperature / time calculations and mechanical force calculations. However, a series of 'live' short circuit tests has recently been carried out which suggest that this type of cable construction may not withstand these bursting forces when subjected to typical fault conditions. Suggestions and reasoning will be given for these findings and a method of safe cable installation will be suggested. (6 pages)Gaussian process regression for virtual metrology of plasma etch
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0485
Plasma etch is a complex semiconductor manufacturing process in which material is removed from the surface of a silicon wafer using a gas in plasma form. As the process etch rate cannot be measured easily during or after processing, virtual metrology is employed to predict the etch rate instantly using ancillary process variables. Virtual metrology is the prediction of metrology variables using other easily accessible variables and mathematical models. This paper investigates the use of Gaussian process regression as a virtual metrology modelling technique for plasma etch data.Application of fractal theory in examination of resistance spot welding quality
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1336
Resistance spot welding is a technology applied extensively in mechanical manufacturing industry, non-destructive testing of resistance spot weld quality has been a hot research project in welding field. In this paper, spot welding tests were carried out and the welding spot surface images were acquired. Testing calculational formula of box-counted dimension were introduced. Calculational method about box-counted dimension was given and program about dimension and image processing based on Matlab were projected. In the end, the relationship between fractal dimension and tensile strength of the welding spot was analyzed, the result showed that the fractal dimension of the welding spot is correlated with the tecsile strength of the welding spot. It provides a basis on using welding spot imprint image to examine the weld quality.System structure and control methods of EPC Internet of book's things
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1088
The application of RFID system is introduced, and the structure characteristics, working principle, components of Electronic Product Code (EPC) system are studied. The control system is analyzed by H<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">∞</sup>, the results of simulation shows that H<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">∞</sup> control is applicable to internet of things system and can improve stability of the system.Artificial intelligence and fuzzy logic based comprehensive motor testing technique
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0081
In the current trend of global design, engineering and sourcing, quality assurance of a given component together with prediction of its performance and estimation of life poses an entire set of challenges. In the case of mass produced fractional horsepower motors which are usually manufactured at one location, assembled into a given system at another location and put for operation in yet another location, they are subjected to varying climatic conditions, handling during shipping that affect their life and field performance significantly. In this scenario, it remains a challenge for manufacturers, tier1 suppliers, OEMs including end customers to ship or accept a particular supply of motors with higher levels of confidence on their life and performance. Consequently the costs towards addressing any unscheduled down-time, warranty claims become high. Globally, the testing approach practiced considers a sample of motors and involves an intrusive testing of the motor. The test platform proves capital intensive, testing cycle is lengthy and the test approach leaves a possibility of passing a faulty motor. This paper presents an in-house developed innovative solution addressing these challenges. The solution integrates the data received from following tests using artificial intelligence and fuzzy logic methods. (a) Design Conformance Test: to capture the extent of deviation from design parameters (b) Impedance Analysis: to capture the health of insulation and winding (c) Motor Current Signature Analysis: to capture the mechanical defects like eccentricity of the motor, improper bearing fittings, broken or damaged rotors (d) Reaction Analysis: to capture how well the motor responds to changes in load as compared to its design parameters including acoustic noise and vibration. In addition to the above four tests, the analysis also considers historical (warranty), geographical, climatic conditions data, shipping process. The primary advantages of this solution are: (a) Inclusion of this comprehensive test in functional testing process eliminates the need to do a random sampling of motors for intrusive testing (b) Significant reduction of total testing cycle time a specific example has realized a reduction from 4 hours to about 90 seconds (c) Prediction of performance and estimation of life of a given motor for any given operating conditions. (6 pages)HVAC test on 132 kV XLPE cable circuits with special switching arrangement
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1778
This paper describes CLPP's experience on conducting HVAC tests on 132 kV transmission XLPE cable installations, the testing standards adopted and the special site arrangements for setting up the HVAC test sets. A summary of the HVAC results and the testing arrangement for new XLPE cable jointed to the old cable system are also included. (6 pages)Partial discharge monitoring system for CLP power strategic 400 kV GIS extension at black point power station
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1745
CLP Power Hong Kong Limited (CLP Power) has reinforced its 400 kV power grid by introducing new extension switchgear to the Black Point Power Station (BKP). Since the circuits are of strategic importance to provide more generation infeed capacity and any fault must be avoided by all means, if possible, to ensure high supply reliability, CLP Power has created a cooperative arrangement with Mitsubishi Electric, the original equipment manufacturer of the 400 kV gas insulated switchgear (GIS) for BKP to establish an effective solution using the condition-based maintenance (CBM) approach. So an On-line partial discharge (PD) monitoring system has been installed with operation and maintenance support from the manufacturer. The design of the PD coupler has been integrated with the GIS design, with high sensitivity and reliability, while meeting recognized standards. The system can also cope with future expansion. Establishing a methodology on how to diagnose the insulation healthiness of GIS using the PD monitoring system is of high importance to the CBM practice. The PD monitoring system has been working satisfactorily since its full commissioning in June 2008. There is also a good collaboration between the teams in building up the future CBM requirements through the analysis of PD monitoring data and providing expertise support. The paper is intended to share (a) the information on key technical requirements, system design, architecture, layout arrangement and provisions on the GIS of the PD monitoring and, (b) the experience in factory acceptance test, site acceptance test and subsequent operation of the system. (6 pages)Initial results from processing of acoustic emission signals from small diameter drilling
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1702
Tool condition monitoring (TCM) measures the condition of a cutting tool used in machining, and provides the operator with information relating to the state of the process. A TCM system gathers data about a process using a number of different sensor types, including force, motor power, strain, vibration and acoustic emission. With pressure on the manufacturing industry to reduce material waste and increase productivity, the dependence on TCM systems is ever increasing. Unreliable TCM can allow a process to continue with a broken or worn tool which may damage the workpiece. This is problematic as workpieces can have a high embedded value, or the machine can be making scrap for significant periods which can be costly. On the other hand, time is wasted changing a tool too often or resetting after false alarms which is also costly. Therefore increasing the reliability of TCM systems is of critical importance to a manufacturing system. A further challenge to TCM is presented in micro machining processes, in particular with small diameter drilling. In small diameter drilling it can be very difficult to detect variations in the measurable phenomena due to the low levels recorded by sensors. One sensor that has been shown to detect valuable information during micro machining and micro drilling is an Acoustic Emission (AE) sensor. This paper outlines the an approach to processing an AE signal from micro drilling in order to provide information on the process parameters. The challenges and limitations of the analysis are discussed. (8 pages)The value of type testing cables and accessories
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0561
In this paper the results of 16 years of type testing MV, HV and EHV cables, accessories and cable systems are presented as general figures and subdivided by cable, the various types of accessories and by standard. This survey is an update of a previous publication and confirms the previously presented data. It shows that 20% to 50% of all type tests on accessories result in a change in design or stopping the type test. These results show the manufacturer the necessity of thoroughly testing new designs of cables and accessories. For the user of cable systems, these results indicate the value of purchasing type tested components or even systems. Also, these results may help manufacturers and utilities to define a series of relevant tests. Interfacial problems show the importance of testing the combination of cable and accessories that will be used. Individually type tested components are not a guarantee that the combination will pass the type test. In this view, it is advisable, especially for large cable projects, to type test the envisaged combination of cable and accessories before installation commences. (4 pages)Development of a test protocol for a 15 KV class solid-state current limiter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0820
The solid-state fault current limiter (SSFCL) is a new product for which no industry standard exists. This paper gives the overview of the effort to date to develop the test protocol for this new product. It involves the review of existing standards of several legacy electrical gears, survey of the high voltage test facilities, and review of acceptance test criteria of several leading US-based electrical utilities. The resulting test protocol is a comprehensive document to apply to SSFCL to provide a reliable new product. (8 pages)Power frequency overvoltages generated by solar plants
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0589
A new kind of overvoltage, not covered by present standards, has been detected in solar plants when switching the inverters off. This power frequency overvoltage can be transmitted to the MV network, giving rise to damages to some pieces of low voltage electronic equipment. This phenomenon has been investigated in the field, testing several inverters in different solar plants, where the overvoltages, as well as the damages in revenue meters, have been reproduced and recorded. It has been proved that some inverter configurations are more prone to create severe overvoltages than other. In addition, some solutions have been tested. (4 pages)The IAM's sustainable infrastructure initiative
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080567
The presentation will provide an overview on the lAM's sustainable infrastructure initiative and its current activities.Transformers user requirements, specification and testing
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080538
This presentation looks at transformers from the users' (utilities') point of view and discusses the important aspects to be considered when procuring a transformer. The main functional requirements (voltage ratio, MVA rating, impedance, etc.) are discussed together with other important qualities, e.g. reliability and maintainability. The specification process, including the use of standards is then discussed. Finally, the important aspects of factory acceptance testing are discussed, to ensure the end product meets the initial requirements.Simple design support method for thermal reliability of BGA packages
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080195
This paper presents a design support methods to evaluate thermal fatigue life of solder balls on ball grid array (BGA) package. Since high density packages have interactions between design factors, cluster analysis was used to extracts relations between design factors. Simplified BGA package model was proposed to evaluate thermal fatigue life quickly. Then, the mechanism generating inelastic strain falls into the difference in the coefficient of thermal expansion (CTE), Young's modulus of the package and the PCB. An estimating function to equivalent inelastic strain range was developed based on the mechanism. The function can estimate the value to a set of design factors within 20% error.Basic measuring and testing techniques
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080544
First general aspects of measuring and testing in relation with high voltage apparatus will be described. The generation and the measurement of the different kind of test voltages like DC, AC and impulse voltages will be demonstrated on examples and the main features of the generation systems and measuring systems will be stressed. The required test conditions and the evaluation of test results will be discussed including the actual status of the relevant recommendations. Finally the procedure and the requirements for verifying equipment at its commissioning by on-site tests will be presented.Impact of the 17th Edition of the Wiring Regulations: how it affects the commercial customer
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080627
The article consists of presentation slides on IEE wiring regulations. The areas discussed include: initial & periodic inspections of competence of installations within complex buildings; compliance of non-permanent pre-built displays; managing alterations and plant renewals; preventive maintenance and electrical accidents. (15 pages)Time synchronized end to end testing using IRIG-B
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080108
Testing distributed arrangements of protective devices often requires distributed test equipment for comprehensive assessment. The test units need to be synchronized in order to provide properly interpretable signals to the devices under test. While there are diverse ways to achieve this goal, one efficient way is to make use of IRIG-B signals that are available on site, e.g. for time logging purposes. Some basics about IRIG-B, new approaches and hints for end-to-end testing with dedicated test equipment are discussed in this paper.DSAC report 'specification and measurement of radar performance' - have we fully exploited its findings?
http://dl-live.theiet.org/content/conferences/10.1049/cp_20070513
The report "specification and measurement of radar performance" (S. Watts, et al., Oct. 2002) was commissioned by the defence scientific advisory council (DSAC) and summarised in a presentation to Radar 2002 by Professor Simon Watts. There have been some significant developments in the way projects are specified and managed in the 5 years following the report. So what has changed and what can still be learnt? The paper presents some advances, particularly in the area of synthetic test environments as a tool in support of through-life capability management (TLCM) that allow real-world trials to be reduced and focussed on the really difficult-to-simulate issues. (4 pages)Virtual prototyping & failure mode and effect analysis (FMEA) in industrial design processes on the basis of mobile device terminals
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.1087
During the product design and development phase of mobile telecommunications equipment (MTE) it is crucial to assess and predict potential failures of the device at an early stage and in particular prior to mass production. This study investigated whether enhanced TCAD environments, combined with automation and Genetic Algorithm based optimization, can proof its value to identify failure modes and their effects to RF performance. The validation is presented based on a quadband phone which was introduced into market recently. The study finally demonstrates that speed and feature enhanced TCAD tools exceed the use as a common simulation platform and revealed its value as a predictive engineering tool for product development environment. (5 pages)Application of displaced beam method on antenna radiation pattern measurement
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.1244
The purpose of our work was to create software with implemented displaced beam method (DBM) that enables to transform of a Fresnel region antenna pattern to a far field pattern for linear and circular antenna apertures. Further goal was to carry out of the testing of this method. The developed software includes an effective technique for random errors elimination and a tool for systematic errors indication. The systematic errors are mostly caused by inaccurate antenna mounting on a turntable and rotating out of antenna phase centre in process of antenna radiation pattern measurement. (4 pages)Large scale video delivery using hybrid packet/circuit multicasting: experiences from Chinese broadband network testbed (3TNet)
http://dl-live.theiet.org/content/conferences/10.1049/ic_20070183
To support large scale video delivery, we carried out a hybrid packet/circuit multicasting field trial with 26000 users. Each end user has 40 Mb/s guaranteed bandwidth. The results of 1040 concurrent users testing ware reported. (2 pages)Tests of a 1.5-m reflector antenna in a 650 GHZ hologram CATR
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.1251
MilliLab/Radio Laboratory at the Helsinki University of Technology (TKK) is developing a hologram-based compact antenna test range (CATR) for high gain antenna testing at millimetre and sub-millimetre wavelengths. The capabilities of the hologram CATR were demonstrated in an antenna test campaign, where the ADMIRALS RTO was tested at the frequency of 650 GHz. The binary amplitude hologram used as the collimator has a diameter of 3.16 m. The quiet-zone width was 2 m and height 2.3 m. In this paper, the construction of the hologram CATR is presented. Also, some results of the quiet-zone field verification and the antenna tests are presented. Stretching of the hologram substrate and its effect on the quiet-zone field are studied. (6 pages)Characterization of radoms for millimetrewave radar applications
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.1586
Characterization of material to build radoms is important for their use in applications. The present procedure to do so was a heating test to determine material parameters at different temperatures. These tests did not include effects caused by wind and high pressure. In this presentation an experimental setup is described which simulates the exposure of the radom material to supersonic speed conditions. In particular this includes a specially designed antenna to look through the material laterally to get rid of effects caused by multipath propagation. Measurements at 35 GHz are also presented. (3 pages)Effectiveness of software solutions in reducing errors due to multi-path in spherical near field measurements
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.0918
Summary form only given. The presence of multi-path reflections is usually a source of significant error in low frequency spherical near field measurements as the test antennas typically have low gain and the cost of lining the anechoic chamber with optimal low reflectivity is prohibitive. Some earlier papers have discussed the effects of there errors on far field patterns and mitigation of some of the errors using hardware solutions and by range optimization. Many of the commercially available software suits for near-field to far field conversion provide algorithms and utilities for reducing the errors due to multi-path. Some examples of such software solutions include MARS add-on for Near Field Systems Inc. (NSI), IsoFilter technique from MI Technologies, and Spherical mode filtering routines in CASAMS and TICRA SNIFTD software. These techniques generally require either over sampling of measured data or mounting the antenna such that the phase centre is displaced with respect to the centre of measurement thereby acquiring data on a sphere larger than the minimum sphere originating at the phase centre. The error reduction algorithms then estimate and filter out the contribution due to multi- path This paper presents the results of a study undertaken to determine the effectiveness of some of these algorithms in reducing the multi-path errors in a low frequency measurement facility. A variety of antennas such as horn antennas, log-periodic, helical and phased arrays were measured in a spherical near field facility housed in a sub-optimally lined anechoic chamber. The far field data with and without the software correction was compared to the expected behaviour of the antenna calculated using numerical techniques. The results of these measurements showing the effectiveness and limitations of the techniques studied will be presented. Practical considerations in reaching optimal solutions will be discussed. (1 page)EMC issues in advanced signalling, transmission based train control systems
http://dl-live.theiet.org/content/conferences/10.1049/ic_20060187
This paper is an independent evaluation of problems encountered on railways when parts in signalling/train control systems are susceptible to intense, or impulsive electrical and electromagnetic effects. Impulse testing of the communication channels and analysis of responses are significant aspects of the design, build and proving of commercial and domestic digital and communication equipment. EMI and EMC issues may reduce performance. Observations and detailed measurements are the main ways to determine data error rate differences. The French Morane trials did achieve some good comparative results. There are other root causes and factors to consider in practice, train loadings, extreme weather, couplers, cable degradation, component wear and timing period failures occur. The purpose of this paper is to show complex and previously partial understood effect from DC traction GTO impulses can be capture and explained when manufacturers/designers, researchers, trained specialists and users cooperate and accept that both abnormal and normal behaviours of signalling/train control systems have to be addressed together.Design and tests of a hybrid-optical direct current transformer
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061846
The designs and tests of a hybrid-optical direct current transformer (HOCT) are demonstrated, which consists of a shunt, a coil, an opto-electric transmission system and some electronics. The experiment results show that the DC measurement meets the 0.2 accuracy class standards and the harmonic measurement confirms with GB/T 14549-93 for harmonic of public power. (4 pages)Diagnostic testing for assessment of PILC cables
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061904
Distribution network utilities are becoming more cognizant on the importance of their capability to improve the condition and reliability of their network system. A combination of appropriate diagnostic testings are sought after for condition monitoring and assessment. Selection of the most appropriate diagnostic system between the one that are already developed and practiced and others that are promising but still in development is not an easy task to achieve. The performance of PILC cable is crucial in terms of supply reliability as its total length is still significant in the network. Therefore, monitoring the condition of these cables is considered very important and has to be looked into seriously. Tenaga Nasional Berhad has initiated its journey on diagnostic testing for distribution cables in 1996. The activities began with the introduction of partial discharge mapping. Dielectric spectroscopy was introduced at the end of 2001. Since 2004, both the diagnostic tests are being carried out on the same selected cable circuits. The main purpose of the testing is to assess the capabilities of the technologies and to develop knowledge on interpretation of the results obtained. The cables are first tested with Dielectric Spectroscopy. The partial discharge mapping is then carried out for localization discharge sources. The results from the tests conducted are analysed to evaluate the condition of the cable under test. This assessment exercise is used to come up with necessary proposals for the next course of action to be taken, if necessary, on the tested cables. (6 pages)What is a CLEF and what does one do and why do we do it?
http://dl-live.theiet.org/content/conferences/10.1049/ic_20050598
A collection of slides from the author's conference presentation is given. (2 pages)From micro to nano; system-on-chip and beyond
http://dl-live.theiet.org/content/conferences/10.1049/ic_20050189
Presents a collection of Powerpoint slides covering the development of semiconductor manufacturing at Philips to nanotechnology, system-on-chip and future developments.Taiwan: from chip foundries to system-on-chip design
http://dl-live.theiet.org/content/conferences/10.1049/ic_20050595
A collection of slides from the author's conference presentation is given. (8 pages)A low-power high precision self-testing data acquisition system for a large seismic exploration grid
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050142
In seismic exploration for oil and gas, a grid of 2,000 to 30,000 nodes is formed to acquire reflected wave signals from the rock layers in the Earth. Each node consists of a sensor, complete data acquisition system with self-test, and telemetry for returning data to a central recording unit. This demanding application requires a highly linear, wide dynamic range data acquisition system with a 0.1-200 Hz bandwidth. A large number of nodes operating simultaneously require that each node consume very low power. The components of each data acquisition node are: a geophone or a hydrophone (sensors for land and marine exploration respectively), a programmable gain differential amplifier, a delta-sigma analog to digital converter, a multi-function decimation filter, and a high precision DAC for calibration and self-test. Each of these components is optimally designed for low power in large sensor arrays. The acquisition node requires self-calibration capability and operation in a synchronous mode where all channels acquire data simultaneously. A data acquisition system that meets these requirements has been designed and tested. The overall performance of the system is better than 112 dB linearity (THD) and 123 dB dynamic range (SNR) at 500 SPS. The power consumption for the data acquisition portion of a single node is 105 mW from a 5 V analog power supply.Vector control technique and sleep-transistor allocation for supply-gating current spike reduction in power management
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051551
Power-gating is an effective approach for reducing both dynamic and static power dissipation in power management and test scheduling. This paper formulates the power-gating spike problem, derives a reduced power dissipation model as heuristics, proposes a vector control technique for post-gating circuits, and develops a sleep-transistor allocation scheme for power-on/off current spikes reduction of pre-gating systems. From experimental results, a justified controlling vector can reduce the on/off peak power up to 55%. For a pre-gating system, more than 83% of the power-gating spike can be reduced. From our preliminary simulations using HSPICE so far, this heuristics has been proved to reduce the supply-gating current spike. (4 pages)Short circuit tests for detection of high impedance faults
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050972
This project presents a summary of the tests realized with equipment, with the purpose of detecting the high impedance faults that occur in the electrical systems, and also the researches done to evaluate the status of the art of equipment and/or processes used to detect the high impedance faults of the electrical energy distribution system. During the tests, short circuit tests were made, with normal, aluminum and aluminum with steel soul cables, provoking with same fallen cables over several different kinds of soil, with a great variety of contact resistivity with the soil, also the cases of covered cables were tested, used in compact network, in both 13.8 kV and 34.5 kV, proving that these currents of short circuit of cables fallen to the soil are very small. (4 pages)Test of PWM power electronics devices for electricity network using digital real-time simulator
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050988
This paper presents a new solution to obtain real-time simulation of PWM power electronic devices. As a validation, a benchmark was realized for testing a static VAr generator (SVG, also called D-STATCOM or SVC light) control device for distribution power systems. The tests of power system equipments are required either in the design phase, during the qualification and the validation, or in case of malfunctions. These tests are needed to check equipment's behavior itself as well as its interactions with the power system. An effective and flexible solution to realize these tests avoiding device destruction and voltage risks for people is to use digital real-time simulation. (5 pages)Quality control of XLPE cables by means of impulse voltage test
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050981
High voltage cable lines are rated among the most expensive investments in the electric energy supply system. Due to economic and operational requirements these lines are to live up to the highest expectations as far as reliability and adequate life time are concerned. Therefore it is recommended to undertake impulse voltage tests with increased level apart from tests as provided in the relevant standards. Thanks to these examinations impurities in the insulation and in the interface between insulation and semi conductive layers can be recognized fast and easily for they cause lower levels of the impulse strength. Particularly so-called protrusions in the interface between insulation and semi conductive layers or inadequate adhesion of the semi conductive layers to the insulation, both defects that can occur during the production of the cable, are subjected to the test. During operation these impurities can cause increased local electrical field strength in the insulation as well as water trees and electrical trees. Additionally they speed up the aging process in the insulation of the cable and this can lead to early faults respectively a shorter life time. These production related defects are not detectable by standard tests as partial discharge measurement or voltage tests with power frequency. Due to our investigations and good experience in the field of quality control of XLPE cables we carry out this test for all Austrian and some German utilities. (3 pages)Tools for partial discharge testing MV cables and plant
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050983
This paper describes the development and application of tools to distinguish between noise and PD activity, and to distinguish between several different types of PD. The recognition is done using simple algorithms which use the waveform shape of the PD (and noise) pulses, to discriminate between the different types. The paper also describes a localisation method for PD pulses on cable systems. The objective of this work is to develop a reliable PD detection system which detects and locates the PD activity, especially for on-line measurements. By removing two of the largest obstacles to making good PD measurements on high voltage plant, namely: 1) noise reduction of radio interference from broadcasts and power line carrier signals; and 2) separation of noise pulses from cable PD pulses and local equipment PD pulses. (4 pages)Factory testing of long submarine XLPE cables using frequency-tuned resonant systems
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050959
This paper addresses the principles of testing long submarine solid dielectric cables with AC-voltage, using up to date high voltage equipment with frequency tuning. It is shown that lengths up to 100 km or more is possible to test if all parameters affecting such tests are taken into account and treated accurately. Whether an AC or a DC solid dielectric cable is chosen, an successful AC factory test with enhanced phase to ground voltage, give high credibility to the XLPE technologies of today. (5 pages)Risk assessment of fixed defects in GIS under different voltage wave shapes
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051397
SF<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">6</sub> gas has nowadays established itself as a reliable insulating medium for gas-insulated switchgear (GIS). In GIS however different kind of defects may occur, such as protrusions fixed to the conductors. Such defects locally enhance the electric field, which can result in partial discharge (PD) activity or even breakdown. For the application of condition based maintenance (CBM) on GIS, it is important to be able to assess its insulation condition. Aspects, which have to be taken into account, are sensitive detection of partial discharge activity, identification and location of the discharging source and probability for breakdown. In this paper, the criticality or probability for breakdown of fixed defects has been investigated. For this purpose, AC voltages have been applied to study the breakdown probabilities under pure AC condition. Secondly, the defects have been tested with standard lightning impulses (LI) and switching impulses (SI) and finally a bias-test was performed. Based on above-mentioned results, knowledge rules for risk assessment tools have been defined. (4 pages)Unique virtual power system technology used in a low power network to provide solution testing for distributed generation
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051259
This paper deals with the testing of electrical machines, to have full control over the network to which they are connected. Control of the networks impedance, voltage, and frequency, and the ability to test machines under network fault conditions are all desirable attributes for a test facility. There is particular interest in testing machines at present, since the machine parameters for generating electricity from intermittent renewable sources are unlike those parameters from gas or steam turbines, and there are concerns relating to grid stability under scenarios with high penetrations of renewable generators. (4 pages)Development and application of insulated shading mask for cable testing
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050966
Cables in distribution network have to carry a withstand voltage to check the insulation of the cable itself and its accessories before being put into operation or during the preventing testing. But most of the cable pothead and its leads are keep in the switchgear cabinet where the clearances between phases or to ground are limited due to the compact design of the cabinets. The clearances cannot meet the safety requirements during high voltage testing. So an insulated shading mask was developed and had proven it meets all the safety requirements. (2 pages)The advantages of a two year wet ageing test to the service performance of the medium voltage grid
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050968
Cables form an important part of the electrical power transmission and distribution networks as they carry power to areas that are not accessible by overhead lines. In addition, cables bring increased levels of reliability and lower maintenance burden. A continuous focus on the quality and performance required from cables being installed will minimise the total lifetime costs. The common themes that contribute to achieving higher quality cables are: 1) utility attention to regular monitoring of the wet ageing performances as well as approval tests; 2) focus on consistency of quality; 3) setting appropriate success criteria for ageing tests; 4) monitoring the quality of cables by an ongoing production monitoring test; and 5) monitoring the quality of the compound used. (4 pages)