1kHz Sampling Rate Research Articles

Economical Setting-Free Double-Ended Fault Locator for Transmission Lines: Experiences From Recent Pilot Installations

Locating fault precisely on power transmission line is highly beneficial to utilities and accurate fault location can expedite the repair of the faulted components, speed-up restoration, and reduce outage time. In this paper, a setting-free double ended fault location method for power transmission line is proposed using both end voltage and current measurements. This algorithm estimates the required setting parameters using pre-fault data and fault location is calculated using estimated parameters and during fault data. The proposed method is verified using the EMTDC simulations for lines connected with conventional and inverter-based renewable resources. The method is not affected by the error in line parameters and renewable integration. The method is implemented in Intelligent Electronic Device (IED) using 1kHz sampling rate and successfully installed on a 400 kV, 233.07 km line from Power Grid Corporation of India (POWERGRID), India and on a 220 kV, 265.6 km line from Svenska Kraftnat (SVK), Sweden. This paper presents laboratory test results as well as field experimental results in which line patrolling crews found the actual location. Pilot installation results match the performance demonstrated with laboratory experimental results. The method gives average fault location error of ~ 0.1 %. The method can locate the fault within two-tower span distance (~300m) which is comparable with traveling wave-based method that requires 1000 times higher sampling rate, high-cost hardware, more complex commissioning, and settings. These geographically diverse pilot installation results stand as testimony to the fault location accuracy of the proposed setting-free fault location solution.

Differences in Physiological Signals Due to Age and Exercise Habits of Subjects during Cycling Exercise.

Numerous studies indicated the physical benefits of regular exercise, but the neurophysiological mechanisms of regular exercise in elders were less investigated. We aimed to compare changes in brain activity during exercise in elderly people and in young adults with and without regular exercise habits. A total of 36 healthy young adults (M/F:18/18) and 35 healthy elderly adults (M/F:20/15) participated in this study. According to exercise habits, each age group were classified into regular and occasional exerciser groups. ECG, EEG, and EMG signals were recorded using V-AMP with a 1-kHz sampling rate. The participants were instructed to perform three 5-min bicycle rides with different exercise loads. The EEG spectral power of elders who exercised regularly revealed the strongest positive correlation with their exercise intensity by using Pearson correlation analysis. The results demonstrate that exercise-induced significant cortical activation in the elderly participants who exercised regularly, and most of the p-values are less than 0.001. No significant correlation was observed between spectral power and exercise intensity in the elders who exercised occasionally. The young participants who exercised regularly had greater cardiac and neurobiological efficiency. Our results may provide a new exercise therapy reference for adult groups with different exercise habits, especially for the elders.

Measurement of spontaneous blinks in patients with Parkinson's disease using a new high-speed blink analysis system

IntroductionParkinson's disease (PD) patients often have a blinking abnormality. In this study, we examined the kinematic features of spontaneous blinking in 65 PD patients and 62 healthy controls by a new research method utilizing an intelligent vision sensor camera prototype with a 1kHz sampling rate. MethodsSpontaneous blinks were measured by use of a non-stress ‘intelligent vision sensor’ camera prototype. ResultsThe mean spontaneous blink rate was 17.9 (blinks/min) in the PD patients and 15.6 in the controls (no correlation). However, there were extremely low and extremely high blink-rate groups among the PD patients. The amplitude of the closing and opening phase in the PD patients were significantly smaller than those in the controls. Small blink waves (100–200msec) prior to blink onset existed in 60% of the PD patients and in 18% of the controls. ConclusionDuring spontaneous blinking the blink amplitude is decreased, and the pause between the closing and opening phase is prolonged in patients with PD. Small blink waves prior to blink onset were also characteristically found in the PD patients.

An Energy-Efficient Frequency-Domain CMOS Temperature Sensor With Switched Vernier Time-to-Digital Conversion

This paper presents a CMOS smart temperature sensor using a switched Vernier time-to-digital converter to achieve an energy-efficient temperature sensing. The proposed temperature sensor employs two switched ring oscillators (SROs), of which the oscillation frequencies are slightly different from each other and varying linearly with temperature due to the deployment of a proportional-to-absolute-temperature current generator. The frequencies of the two SROs are measured by counting the rising edges with two counters, and hence, the frequency difference corresponding to temperature can be readily monitored with the digital numbers. A control strategy that switches OFF the ring oscillators after each sampling is developed, such that significant power saving is achieved. The proposed temperature sensor shows a measured resolution of 0.048 °C from −20 °C to 120 °C with 100-ms conversation time. With 1-kHz sampling rate, the power consumption is as small as 93.6 $\mu \text{W}$ , resulting in 93.6 nJ per sampling. The chip area is 0.118 mm2 in a standard 0.18- $\mu \text{m}$ CMOS process.

The effect of accelerometer mass in mechanomyography measurements

Mechanomyography (MMG) signals record and quantify low-frequency lateral oscillations of active skeletal muscles. These oscillations reflect the ‘‘mechanical counterpart’’ of the motor unit activity measured by electromyography (EMG). Accelerometers have been commonly used to measure MMG. However, the accelerometer mass can affect the MMG signal. The purpose of this paper was to investigate the relationship of the accelerometer mass and the MMG signal. Thirty-two normal volunteers conducted the maximum voluntary contraction of leg extension. MMG signals were obtained from the rectus femoris muscle using an accelerometer. For each subject, the accelerometer mass was varied from 3, 8, 13, 18, 23 and 28 g. The signals were measured for three seconds with a sampling rate of 1kHz. Results showed that the MMG signal amplitude increased as the accelerometer mass increased. However, the median frequency (MF) of the MMG signal decreased with the increased accelerometer mass. When the accelerometer mass increased from 8 g to 13 g, the amplitude of the MMG signal increased the most, and the MF of the MMG signal decreased the most. However, for accelerometers heavier than 13 g, no significant change was observed in both the amplitude and MF. Based on the present study, the mass of the accelerometer is recommended to not exceed 13 g to properly measure MMG signals.

Distributed measurement of dynamic strain based on multi-slope assisted fast BOTDA.

We propose and demonstrate a dynamic Brillouin optical fiber sensing based on the multi-slope assisted fast Brillouin optical time-domain analysis (F-BOTDA), which enables the measurement of a large strain with real-time data processing. The multi-slope assisted F-BOTDA is realized based on the double-slope demodulation and frequency-agile modulation, which significantly increases the measurement range compared with the single- or double- slope assisted F-BOTDA, while maintaining the advantage of fast data processing and being suitable for real-time on-line monitoring. A maximum strain variation up to 5000με is measured in a 32-m fiber with a spatial resolution of ~1m and a sampling rate of 1kHz. The frequency of the strain is 12.8Hz, which is limited by the rotation rate of the motor used to load the force on the fiber. Furthermore, the influence of the frequency difference between two adjacent probe tones on the measurement error is studied theoretically and experimentally for optimization. For a Brillouin gain spectrum with a 78-MHz width, the optimum frequency difference is ~40MHz. The measurement error of Brillouin frequency shift is less than 3MHz over the whole measurement range (241MHz).

Study on the applicability of polytetrafluoroethylene–silver composite thin films as sensor material

A study on applicability of conductive high specific surface PTFE/Ag composite layers as active electrodes of a non-enzymatic cholesterol sensor is presented. The composite layers were prepared on one of the two neighboring electrode of a printed circuit board by pulsed laser deposition technique where targets composed of silver and PTFE were ablated by an ArF excimer laser. Cholesterol was dissolved in 0.1M NaOH in different concentrations in 0–5mM range. A drop of cholesterol covered the two electrodes and a constant current of 10μA was forced through the sample while the voltage between the electrodes was measured by means of a high resolution A/D converter with 1kHz sampling rate for 5s periods. Instead of the time-averaged signal monitoring we applied the Fluctuation-Enhanced Sensing (FES) method which is based on the analysis of the stochastic component of the signal. The power spectral density of the fluctuation was found to be dependent on the cholesterol concentration of the samples. Principal Component Analysis method was used for quantifying the difference between the recorded spectra. A tendentious variation of the spectral properties as the function of the cholesterol concentration was observed. The results indicate that the FES technique combined with high specific surface composite electrodes may be a useful tool for cholesterol detection.

Deformation measurement of internal components of ASDEX Upgrade using optical strain sensors

A fibre-optic measurement system to analyse the deformation of in-vessel components has successfully been developed, installed and commissioned at ASDEX Upgrade (AUG). This technology has thereby been qualified for in-vessel use at experimental fusion devices. AUG is equipped with an internal conductor for passive plasma stabilisation called the Passive Stabilisation Loop (PSL), on which the recently installed 16 internal coils (B-coils) are directly mounted. The PSL structure is highly prone to vibrations, and the risk of resonant oscillations in response to B-coil induced forces necessitated the development of the present diagnostic. The diagnostic system consists of 34 fibre-optic strain sensors incorporated in two glass fibres. It is completely insensitive to electromagnetic disturbances. The fibres are customised to avoid inconvenient excess fibre length in the vacuum vessel. They were tested for their neutron tolerance and vacuum compatibility prior to installation. The actual sensors are embedded in stainless steel carriers that were attached to the PSL, which is made of copper, by laser welding. Appropriate welding parameters were determined in view of the metallurgical dissimilarity. The weld quality was approved by tensile tests and microscopic investigations. Accurate in-vessel positioning of the sensors was assured using a 3D measurement system and coordinates from CAD. The data acquisition allows a sampling rate of 1kHz. It was shown that the temporal and spatial resolutions of the system are sufficient to resolve the potentially dangerous bending eigenmodes of the PSL rings.

Multi-body power analysis of the baseball pitching based on a double pendulum

In this study, we investigated the manner in which non-muscular forces such as centrifugal, Coriolis, and gravity forces of each link generates, absorbs, and transfers mechanical energy in order to produce maximum velocity. This investigation was carried out using multi-body power analysis derived entirely from the dynamical equations of a three-dimensional (3D) double pendulum with a moving pivot model. The objective of this study was to reassess the motions of the forearm and the wrist joint during baseball pitching. To accomplish this objective, the arm movements of a collegiate male baseball pitcher were captured using a motion capture system at a sampling rate of 1kHz. This analysis clarified that the mechanical energy of the hand segment was transferred via the internal force, which was mainly dominated by the centrifugal force. Whereas the muscle torque applied to the wrist joint absorbed the mechanical energy of the hand segment instead of increasing the energy.

Conditioning and Sampling Issues of EMG Signals in Motion Recognition of Multifunctional Myoelectric Prostheses

Historically, the investigations of electromyography (EMG) pattern recognition-based classification of intentional movements for control of multifunctional prostheses have adopted the filter cut-off frequency and sampling rate that are commonly used in EMG research fields. In practical implementation of a multifunctional prosthesis control, it is desired to have a higher high-pass cut-off frequency to reduce more motion artifacts and to use a lower sampling rate to save the data processing time and memory of the prosthesis controller. However, it remains unclear whether a high high-pass cut-off frequency and a low-sampling rate still preserve sufficient neural control information for accurate classification of movements. In this study, we investigated the effects of high-pass cut-off frequency and sampling rate on accuracy in identifying 11 classes of arm and hand movements in both able-bodied subjects and arm amputees. Compared to a 5-Hz high-pass cut-off frequency, excluding the EMG components below 60Hz decreased the average accuracy of 0.1% in classifying the 11 movements across able-bodied subjects and increased the average accuracy of 0.1 and 0.4% among the transradial (TR) and shoulder disarticulation (SD) amputees, respectively. Using a 500 Hz instead of a 1-kHz sampling rate, the average classification accuracy only dropped about 2.0% in arm amputees. The combination of sampling rate and high-pass cut-off frequency of 500 and 60Hz only resulted in about 2.3% decrease in average accuracy for TR amputees and 0.4% decrease for SD amputees in comparison to the generally used values of 1kHz and 5Hz. These results suggest that the combination of sampling rate of 500Hz and high-pass cut-off frequency of 60Hz should be an optimal selection in EMG recordings for recognition of different arm movements without sacrificing too much of classification accuracy which can also remove most of motion artifacts and power-line interferences for improving the performance of myoelectric prosthesis control.

Source localization of ictal epileptic activity investigated by high resolution EEG and validated by SEEG

High resolution electroencephalography (HR-EEG) combined with source localization methods has mainly been used to study interictal spikes and there have been few studies comparing source localization of scalp ictal patterns with depth EEG. To address this issue, 10 patients with four different scalp ictal patterns (ictal spikes, rhythmic activity, paroxysmal fast activity, obscured) were investigated by both HR-EEG and stereoelectroencephalography (SEEG). Sixty-four scalp-EEG sensors and a sampling rate of 1kHz were used to record scalp ictal patterns. Five different source models (moving dipole, rotating dipole, MUSIC, LORETA, and sLORETA) were used in order to perform source localization. Seven to 10 intracerebral electrodes were implanted during SEEG investigations. For each source model, the concordance between ictal source localization and epileptogenic zone defined by SEEG was assessed. Results were considered to agree if they localized in the same sublobar area as defined by a trained epileptologist. Across the study population, the best concordance between source localization methods and SEEG (9/10) was obtained with equivalent current dipole modeling. MUSIC and LORETA had a concordance of 7/10 whereas sLORETA had a concordance of only 5/10. Four of our patients classified into different groups (ictal spikes, paroxysmal fast activity, obscured) had complete concordance between source localization methods and SEEG. A high signal to noise ratio, a short time window of analysis (<1s) and bandpass filtering around the frequency of rhythmic activity allowed improvement of the source localization results. A high level of agreement between source localization methods and SEEG can be obtained for ictal spike patterns and for scalp-EEG paroxysmal fact activities whereas scalp rhythmic discharges can be accurately localized but originated from seizure propagation network.

Development of A New Accelerometer-Based Physical Activity-Monitoring System Using A High-Frequency Sampling Rate

Physical activity is known to enhance the mechanical competence of weight-bearing bones, and it is also effective for the prevention of osteoporosis. However, little information is available regarding the optimum exercise and intensity of load to weight-bearing bones as well as about a precise system to monitor the intensity of physical activity. To measure the precise load to weight-bearing bones of exercise as a first step, this study is to evaluate the sampling conditions of data acquisition and develop an accelerometer-based physical activity monitoring and its intensity analysis system. Through a simulation experiment, we found that 1k Hz of sampling rate is possible to achieve a measurement error of less than 2%. With the optimum sampling rate of 1k Hz, we developed an accelerometer-based activity-monitoring system. We then assessed the magnitude of acceleration at the shank, knee, and lumber in healthy subjects (n=19) as they descended stairs. A correlation analysis of the precise acceleration values in three points of the body showed that our system could accurately identify the shock absorptive function of lower extremities. Therefore, we strongly believe that our system, with the optimum sampling rate of 1k Hz, produced an accurate measurement of loads acting on weight-bearing bones.

Distributed Fiber Strain Sensor With 1-kHz Sampling Rate Based on Brillouin Optical Correlation Domain Analysis

We report the highest speed distributed sensing of dynamic strain based on stimulated Brillouin scattering in optical fibers. A sampling rate of 1 kHz, more than an order of magnitude higher than the former best result, is achieved by applying a simplified Brillouin optical correlation domain analysis with optimized time gates and an unbalanced Mach-Zehnder delay line. In experiments, we present the measurement of various dynamic strains at the maximum frequency of 200 Hz with 10-cm spatial resolution and 20-m measurement range.

Increased rate of force development and neural drive of human skeletal muscle following resistance training.

The maximal rate of rise in muscle force [rate of force development (RFD)] has important functional consequences as it determines the force that can be generated in the early phase of muscle contraction (0-200 ms). The present study examined the effect of resistance training on contractile RFD and efferent motor outflow ("neural drive") during maximal muscle contraction. Contractile RFD (slope of force-time curve), impulse (time-integrated force), electromyography (EMG) signal amplitude (mean average voltage), and rate of EMG rise (slope of EMG-time curve) were determined (1-kHz sampling rate) during maximal isometric muscle contraction (quadriceps femoris) in 15 male subjects before and after 14 wk of heavy-resistance strength training (38 sessions). Maximal isometric muscle strength [maximal voluntary contraction (MVC)] increased from 291.1 +/- 9.8 to 339.0 +/- 10.2 N. m after training. Contractile RFD determined within time intervals of 30, 50, 100, and 200 ms relative to onset of contraction increased from 1,601 +/- 117 to 2,020 +/- 119 (P < 0.05), 1,802 +/- 121 to 2,201 +/- 106 (P < 0.01), 1,543 +/- 83 to 1,806 +/- 69 (P < 0.01), and 1,141 +/- 45 to 1,363 +/- 44 N. m. s(-1) (P < 0.01), respectively. Corresponding increases were observed in contractile impulse (P < 0.01-0.05). When normalized relative to MVC, contractile RFD increased 15% after training (at zero to one-sixth MVC; P < 0.05). Furthermore, muscle EMG increased (P < 0.01-0.05) 22-143% (mean average voltage) and 41-106% (rate of EMG rise) in the early contraction phase (0-200 ms). In conclusion, increases in explosive muscle strength (contractile RFD and impulse) were observed after heavy-resistance strength training. These findings could be explained by an enhanced neural drive, as evidenced by marked increases in EMG signal amplitude and rate of EMG rise in the early phase of muscle contraction.