Transient Recording System Research Articles

Type D travelling wave fault location on branched underground low‐voltage networks

Low voltage cable faults are frequently associated with arcing at the fault which creates 2 high frequency transients which propagate away from the fault towards opposite ends of the cable and whose difference in arrival times can be used to determine the fault's location using the Type D method. A variant of the Type D method, known as the Transient Recording System (TRS) using asynchronous data acquisition units (ADAU) has been used successfully in situations where multiple branches on a cable have precluded the use of other travelling wave methods. The range, and precision of location, of the TRS method is extended by the use of a Marker Unit (MU) which allows the distance and direction to a fault to be determined relative to the point of connection of the MU. The asynchronous data acquisition units operate in ‘listening’ mode and are triggered by the arrival of the transients created by the fault arc. Prior to triggering, the ADAUs continuously (over)write all received data into their cyclic buffers, including the low amplitude MU pulses. Shortly after triggering the (over)writing of the cyclic buffer stops and earlier (pre-trigger) data retained – including the received MU pulses.

Transient Recording System for Power Supply and High Field Magnet Fault Analysis: Its Use for Magnet Aging Surveillance and Accident Diagnosis

The Laboratoire National des Champs Magnétiques Intenses, which is a member of the European Magnetic Field Laboratory, is the French facility enabling researchers to perform experiments in the highest possible magnetic fields. DC magnetic fields up to 36 T in 34-mm bore are provided at the Grenoble site. Apart from the general control and monitoring system with networked continuously monitoring computers, we developed and installed on each of the seven high-field-magnet sites a standalone transient recording system for power supply and magnet fault analysis, which is a domain where very few studies have been conducted. Introduced in 2011, this system enabled, at first, a characterized classification of recorded events. These can be divided into typical aging transients, coil-turn short-circuit set or reset, and magnet accidents leading to power supply cutoff. In the long run, this system has proven to be a useful tool in magnet aging surveillance and accident diagnosis.

Subcaliber discarding sabot airgun projectiles

Medical literature abounds with reports on injuries and fatalities caused by airgun projectiles. While round balls or diabolo pellets have been the standard projectiles for airguns for decades, today, there are a large number of different airgun projectiles available. A very uncommon--and until now unique--discarding sabot airgun projectile (Sussex Sabo Bullet) was introduced into the market in the 1980s. The projectile, available in 0.177 (4.5 mm) and 0.22 (5.5 mm) caliber, consists of a plastic sabot cup surrounding a subcaliber copper-coated lead projectile in typical bullet shape. Following the typical principle of a discarding sabot projectile, the lightweight sabot is supposed to quickly loose velocity and to fall to the ground downrange while the bullet continues on target. These sabot-loaded projectiles are of special forensic interest due to their non-traceability and ballistic parameters. Therefore, it is the aim of this work to investigate the ballistic performance of these sabot airgun projectiles by high-speed video analyses and by measurement of the kinetic parameters of the projectile parts by a transient recording system as well as observing their physical features after being fired. While the sabot principle worked properly in high-energy airguns (E > 17 J), separation of the core projectile from the sabot cup was also observed when discharged in low-energy airguns (E < 7.5 J). While the velocity of the discarded Sussex Sabo core projectile was very close to the velocity of a diabolo-type reference projectile (RWS Meisterkugel), energy density was up to 60 % higher. To conclude, this work is the first study to demonstrate the regular function of this uncommon type of airgun projectile.

Development and Performance Verification of the GANDALF High-Resolution Transient Recorder System

With present-day detectors in high energy physics one often faces fast analog pulses of a few nanoseconds length which cover large dynamic ranges. In many experiments both amplitude and timing information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which leads to high demands on the separation of pile-up pulses. For an upgrade of the COMPASS experiment at CERN we have designed the GANDALF transient recorder with a resolution of 12 bit@1 GS/s and an analog bandwidth of 500 MHz. Signals are digitized with high precision and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate trigger signals for the experiment. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may be used to disentangle possible pile-up pulses and determine timing information from sampled pulse shapes with a time resolution better than 50 ps.

Inverse modeling of a workpiece temperature and melting depth during microthermal machining by scanning thermal microscope

In this study, a general methodology for estimating the temperature of the upper surface of the workpiece and the melting depth during microthermal machining using scanning thermal microscopy has been proposed. First the probe in the processing system was considered as an inverse heat conduction problem with an unknown workpiece temperature. Once the temperature of the upper surface of the workpiece was estimated, then the workpiece was also regarded as another inverse heat transfer problem due to an unknown melting depth in the boundary condition. The conjugate gradient method was used to solve the inverse problems. In addition, this methodology herein can also be applied to solve other transient heat conduction problems, which involve latent heat transfer and form a solid and liquid phase such as laser processing, solidification in continuous casting process, and transient recording system on phase-change material using atomic force microscopy.

A transient recorder system for applications in high-rate detector systems WCC 1998

Measurements with high-rate two-dimensional imaging gaseous detectors require an adequate data acquisition system which allows to handle and store the detector information. For this purpose, a transient recorder system has been developed and tested at the University of Siegen.In contrast to many today’s systems there is no memory needed to store information which is redundant and not used for the final image reconstruction. Some current applications and measurements of the transient recorder system will be presented. It results that high rates up to 100MHz can be processed without dead time loss at short time scale. However, also the problem of handling the massive data flux in the backend electronics needs to be addressed. Currently the avarage data acquisition time is limited e.g. by the PCI Bus to typically 1–2MHz/4Bytes. Another limitation is the global trigger which has been applied to the system. To solve these problems, some basic ideas about local asynchronous and parallel readout for applications in pixel detectors with big sensitive areas are discussed.

Identification of synchronous generator saturation models based on on-line digital measurements

Accurate stability analysis requires the precise modelling of electric machine saturation phenomena. The paper presents a technique suitable for identifying several typical machine saturation models. It is shown that the technique can be used to identify nonlinearities associated with saturation and cross-magnetisation effects. An algorithm is designed to estimate all parameters of the machine models and the associated saturation functions. Numerical studies on a synchronous generator are included, using online measured data of the Taipower system recorded by the plant transient recording and analysis system. >

Identification of excitation system models based on on-line digital measurements

Accurate and sufficient detailed excitation system models are essential to the precise calculations of power system stability limits. This paper presents, in detail, a procedure for identifying excitation system models based on the online digital measurements from a plant transient recorder system. A solution algorithm for identifying parameters of the excitation system models is devised and implemented. The gradient averaging stochastic approximation method is employed to handle nonlinearity of the power system models. Detailed numerical results based on the online measured data of the Taipower system are included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On-line measurement-based model parameter estimation for synchronous generators: model development and identification schemes

Accurate generator modeling allows for more precise calculations of power system control and stability limits. In this paper, a procedure using a set of measured data from an online plant transient recording and analysis system to develop the synchronous generator model for the Taipower system is described. A continuous-time transfer function matrix is derived for a popular sixth-order synchronous generator model. In order to accommodate the nature of online digital measurements, the transfer function matrix is transformed into a simple discrete-time linear regression model. A measure of discrepancy between the generator model outputs and the online measurements from generators is employed. A modified conjugate gradient method suitable for identifying generator parameters is developed to minimize the measure of discrepancy, from which a set of accurate generator parameter values can be obtained. The merits of the modified conjugate gradient method include its computational efficiency and numerical reliability. The proposed procedure allows simultaneous estimation of all generator parameter values. >

On-line measurement-based model parameter estimation for synchronous generators: solution algorithm and numerical studies

In this paper, a sixth-order synchronous generator model identification technique from online measurements is considered. An algorithm is devised to identify the generator model. A constrained conjugate gradient method is incorporated into the algorithm to guarantee rapid convergence to the final solution. Using the algorithm, a complete generator model is derived from online measurements recorded by a plant transient recording system during a system disturbance. In addition, the algorithm does not greatly rely upon the accuracy of the initial estimates, allowing the initial estimates to deviate reasonably far from the true parameters. Detailed numerical studies of the Taipower system using raw and filtered data are included. >

Development of a frequency-dependent composite load model using the measurement approach

In control and stability studies, load models should realistically represent the aggregate load behavior of all kinds of individual components. In this paper, the development of a composite load model, where the load is represented as a combination of an RC circuit in parallel with an induction motor equivalent circuit, is presented. A procedure is developed for identifying a frequency-dependent composite load model using digital measurements from an on-line transient recording system, taking account of system frequency variation. A nonlinear model parameter estimation technique is described to derive the frequency-dependent load model. A computer program called LMSP has been developed. The program consists of five major phases: user-interface, data manipulation, load model identification; model conversion and system model response evaluation. A case study is presented to illustrate, in particular, the accuracy of the developed model for the representation of dynamic load behaviors of an actual power system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Electrospray-ionization time-of-flight mass spectrometry in protein chemistry

A novel electrospray ionization time-of-flight mass spectrometer with an ion error has been developed. The «orthogonal acceleration» of ions combined with ion storage modulation enables large sensitivity to be obtained with moderate (R>2000) mass resolution. Application of the transient recording system allows simultaneous registration of ions of all masses, with sensiivity equal to that in the single ion monitoring regime. The potenial of this technique is demonstrated by the primary structure determination of cationic peptides from porcine neutrophils and by the studyg of the pathways of recombinant proinsulin proteolytic processing catalyzed by various trypsin forms

A powerful personal computer-based plant transient recording and analysis system

A personal-computer-based plant transient recording and analysis (PTRA) system has been developed under a joint effort between the system planning department of Taiwan Power Company (TPC) and A-D Technology, Inc. The PTRA system is an integrated hardware and software computer system to collect the high resolution data of a power plant's transient conditions. The hardware of the PTRA system consists of Intel 80386-based personal computers, an intelligent data acquisition system, resistor boards, and data communication equipment. Special software modules were developed for the hardware to perform data monitoring, trigger detection, data collection, data transmission, and data analysis. The PTRA system has proved to be effective, accurate, flexible, and easy-to-use. It reveals high potential for various applications on electrical generation and transmission systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Dynamic load models in power systems using the measurement approach

Accurate dynamic load models allow more precise calculations of power system controls and stability limits, which are critical in the planning and operation of power systems. The development of dynamic load models using the measurement approach for the Taipower system are described. Two dynamic load model structures are developed. A procedure for applying a set of measured data from an online transient recording system to develop dynamic load models for the Taipower system is described. A technique based on the concept of confidence interval is used to validate the developed high-order load model structure. Case studies are also presented. >

Investigation of the nonlinear behavior of a partially ionized, turbulent plasma in a magnetic field

In this paper, a number of the methods of nonlinear dynamics are applied to the study of electrostatic turbulence in a magnetized, steady-state, partially ionized plasma. Electrostatic potential fluctuations were obtained by using a capacitative probe. These signals were captured, digitized, and recorded with a LeCroy transient recorder system interfaced to an IBM-AT personal computer. A commercially available software program was used to calculate power spectra, to reconstruct and plot phase portraits, take Poincaré sections, compute correlation dimensions and Lyapunov exponents, and to perform other manipulations of the time series of electrostatic potential fluctuations obtained from the plasma. Evidence of low-dimensional chaos was sought, and trends were investigated which related the state of the turbulence to such plasma parameters as the anode voltage (rms electrostatic potential), background gas pressure (collisionality), and magnetic induction. These variables were found to have a significant effect on the nonlinear dynamics of the plasma.

Liquid chromatography/time-of-flight mass spectrometry with high-speed integrated transient recording

High-performance liquid chromatography (HPLC) has been interfaced to a time-of-flight mass spectrometer. The interface is a continuous flow probe and ions are desorbed from the liquid matrix by energetic ion bombardment. Pulsed and delayed ion extraction from the source permits the use of broad ionization times, results in the production of analog signals in each time-of-flight cycle, and provides both energy and spatial focusing. A high-speed integrated transient recording system has been developed and is also reported. This instrument is the prototype for development of a high-speed, high-mass range LC detector with high duty cycle. Its performance is demonstrated for the separation of several mixtures of small peptides.

Transient Recording System in Pyrotechnic Tests

SHOULD a fighter pilot have need of his Martin‐Baker ejection seat, much of life‐saving action will be over in the blink of an eye. Pyrotechnic charges will have ejected the seat from the cockpit and a rocket motor will have sustained the thrust to carry the seat clear of the stricken aircraft — all within 0.5 of a second of the pilot pulling the firing handle.

A Mobile Automated High-Speed Transient Data Recording and Transmission System

A CAMAC-based mobile automated high-speed transient data recording and transmission system developed for gathering underground nuclear test data in remote areas at the Nevada Test Site is described. The system, which is comprised of a NOVA-820 computer and measurement instrumentation packages interfaced via CAMAC modules, permits baseline and zero-time data to be recorded and transmitted automatically in digital form via microwave data links to a central computer complex for reduction, display, and analysis. The modular software packages developed for this system provide maximum flexibility and efficiency in the tailoring of control and monitoring procedures to match the data requirements of particular tests.

A Magnetic Thin-Film Recording System for Fast Transients in Nuclear Diagnostics

The development of a fast transient recording system is described. A magnetic thin film is used to record an electrical signal in the form of a domain wall. The recorder has a risetime on the order of a nanosecond and a dynamic range of better than 30 dB. Readout of the record is compatible with computer (megabit) cycle times.

Radiation Hardness of a New Magnetic Thin-Film Recording System

Magnetic thin-film memory units of a new transient-recording system designed for nuclear data acquisition were tested for radiation hardness. The films were exposed to neutron and gamma doses on the order of 1012 n/cm2 and 104 R, respectively. Analog signals stored in the films were photographed using a Suchow powder technique before and after the exposure.