Fast Protection Research Articles

A fast current relaying algorithm for distribution systems based on discrete setting value

The traditional current protection uses the RMS value of the current to compare with a setting-value to identify faults, which is the typical protection scheme for the transmission lines of the power distribution systems. The current is calculated by the fast Fourier transform (FFT) algorithm. As the calculation of the RMS current requires a long time, the speed of the current quick break protection is reduced. In this regard, a fast current protection algorithm based on the discrete setting value is presented in this paper to solve this problem. The main emphasis is placed on the construction of the discrete sequence of setting-value and the protection criterion. The protection startup criterion and action criterion are constructed based on comparisons between discrete sequence of setting-value and sampling values of the current fault component. The operation characteristics and reliability of the fast current protection are analyzed. The performance of the novel fast current protection algorithm is compared with that of the conventional current protection through simulations based on PSCAD/EMTDC. The results verified that the novel fast current protection algorithm has good operation characteristics under different fault conditions.

The FlagT4G Vaccine Confers a Strong and Regulated Immunity and Early Virological Protection against Classical Swine Fever.

Control of classical swine fever virus (CSFV) in endemic countries relies on vaccination, mostly using vaccines that do not allow for differentiation of vaccinated from infected animals (DIVA). FlagT4G vaccine is a novel candidate that confers robust immunity and shows DIVA capabilities. The present study assessed the immune response elicited by FlagT4G and its capacity to protect pigs for a short time after vaccination. Five days after a single dose of FlagT4G vaccine, animals were challenged with a highly virulent CSFV strain. A strong, but regulated, interferon-α response was found after vaccination. Vaccinated animals showed clinical and virological protection against the challenge, in the absence of antibody response at 5 days post-vaccination. Upon challenge, a rapid rise in the titers of CSFV neutralizing antibodies and an increase in the IFN-γ producing cells were noticed in all vaccinated-challenged pigs. Meanwhile, unvaccinated pigs showed severe clinical signs and high viral replication, being euthanized before the end of the trial. These animals were unable to generate neutralizing antibodies and IFN-γ responses after the CSFV challenge. The results from the present study assert the fast and efficient protection by FlagT4G, a highly promising tool for CSFV control worldwide.

Fast Discharging Behavior of High Temperature Superconducting Coils With Copper Rings and Plates

Fast energy extraction using dump resistances is an effective method for quench protection of high temperature superconducting (HTS) magnets. Copper frames are often applied in HTS magnets for conduction cooling and mechanical support. Previous studies have shown that copper plates can accelerate the energy release of HTS coils during discharging operations with dump resistance, which is favorable for fast quench protection. Copper rings distributed at the inner and outer diameters of HTS coils can provide a strong mechanical support for the possible electromagnetic strain in high magnetic fields. This paper studies the effect of copper rings and plates on fast discharging process of an insulated HTS double pancake coil by finite element method. An optimized structure composed of copper rings and plates is proposed, and its effect on fast discharge is analyzed. The results show that copper plates show better performance than copper rings in accelerating energy release and reducing hot spot temperature of the coil. During discharging process, the optimized structure can absorb considerable energy from the HTS coil and significantly reduce the hot spot temperature. The optimized structure is a promising alternative for fast quench protection of HTS magnets.

Fast and Sensitive Nonunit Protection Method for HVDC Grids Using Levenberg–Marquardt Algorithm

High voltage dc grids are raised high-speed operation and high reliability requirement for relay protection. This article aims at proposing a protection scheme with high operation speed, high sensitivity, and high reliability. First, the symbolic expressions of the line-mode fault component traveling wave in case of the internal and external faults are derived, which consist of the traveling wave propagation term and the dc line boundary term. It is theoretically demonstrated that the index of the traveling wave propagation term in case of internal faults is greater than that for the external faults, and the index is independent of fault impedance. Second, the Levenberg–Marquardt algorithm is introduced to extract the index and an index-based nonunit protection method as well as the protection scheme is proposed. The proposed method is theoretically robust and independent of fault impedance and fault type. In the validation, the fitting results are indicated that the symbolic expressions are correct and the extracted indices are effective to characterize the location of the faults. Numerous fault cases of different fault distances, fault impedances, and fault types have demonstrated that the proposed protection scheme is of high sensitivity, high operation speed, and high reliability.

Performance of a protection system for DC grids

The development of High Voltage Direct Current (HVDC) transmission technology is still challenging due to unresolved technical issues, mostly in terms of protecting the system. The overcurrents and voltage drop produced by fault conditions are severely dangerous to the Voltage Source Converters’ (VSC) electronic components. Hence, fast protection systems are needed. This paper proposes a fullselective protection system in conjunction with hybrid HVDC circuit breakers. This protection system employs the rate-ofchange-of-voltage and the differential-current algorithms for primary and backup fault protections. This protection scheme is applied to a HVDC grid and an analysis of its performance is presented. This system is evaluated with several fault scenarios that include different fault characteristics. The rate-of-change-ofvoltage algorithm’s fast operation and the differential-current algorithm’s high selectivity are verified.

Improved Na-ion kinetics of 1T MoS2 nanopatterned porous hard carbon as an ultra-long life anode

Porous hard carbons (PHC) are promising anode materials in sodium-ion batteries; however, the availability of large surface area creates numerous irreversible active sites that cause rapid initial cycle capacity fading and electrode degradation, resulting in lower specific capacity and poor cycle stability. PHC surface modification via 2D transition metal dichalcogenides is a synergistic approach to combine excellent electrochemical properties of both materials and resolve these issues. Therefore, we designed 1T MoS2 nanopatterned PHC skeleton using carbonization and hydrothermal treatment of biomass (chickpea husk). As a result, HC@MoS2-II electrode with extended d002 spacing of MoS2 nanolayers (0.650 nm) exhibited an excellent specific capacity of 470 mAh/g at 50 mA/g with high initial coulombic efficiency (63%) and ultra-long cycle stability (190 mAh/g) at 1000 mA/g over 3500 cycles. The extraordinary electrochemical performance can be attributed to the synergistic assembly, where the high surface area PHC skeleton effectively buffered large volume expansion during charging/discharging, and 1T MoS2 nanoflowers added fast ionic diffusion kinetics and PHC surface protection.

Attention to vulnerable people in the First Constitutional and Social Transitory Chamber of the Supreme Court of the Republic in Lima

Object of study: The objective of the research was to explain how vulnerable people are treated in the First Constitutional and Social Transitory Court of the Supreme Court of the Republic, in Lima; that is, how is the preferential treatment of people in vulnerable situations: people over 75 years of age, the disabled and others. Methodology: A descriptive qualitative methodology was used, which allowed us to understand the way in which the fourteen participants in this research appreciated the phenomena or events through the understanding of the main aspects of the phenomena, of the facts under observation or of the relationships established by the subjects. This research will provide a service to jurisdictional operators and citizens seeking fast and efficient jurisdictional protection; optimizing and improving the attention of the community in the judicial processes that reach this institution, based on conceptual formulations and implementation measures related to this problem. Main results: The results show us that the attention to vulnerable persons in the First Supreme Court is inadequate due to the existing procedural overload; that is, it is not prompt, which affects compliance with the deadlines established in the legal regulations in force, of the controversies of the administrative process and will contribute to the modernization of the mentioned judicial body in order to provide a better service to its users. Theoretical contributions: Rights must be complemented by political and social rights that allow the needs of the most vulnerable to be met, alleviating their suffering and providing them with opportunities for progress. To safeguard the vulnerable, bioethics must be considered in public policies by standardizing their care practices.

Cognitive Edge Computing–Based Fault Detection and Location Strategy for Active Distribution Networks

This article proposes a fault detection and location strategy based on cognitive edge computing to harvest the benefits of cognitive edge computing and address the special needs of active distribution networks (ADNs). In the proposed strategy, an ADN smart gateway is used to compile data in a central repository where it will be processed and analyzed. The intermediary smart gateway includes a protection unit where the fault detection, location, and isolation are accomplished through a combination of virtual mode decomposition (VMD), support vector machine (SVM,) and long short-term memory (LSTM)–type deep machine learning tools. The local measurements of branch currents and bus voltages are processed through VMD, and the informative decomposed components are provided as inputs to the SVM-based fault detection unit and LSTM-based fault location unit. The smart digital relay passes trip commands to the respective circuit breaker/s and submits compiled data regarding the history of faults and protection actions to the upper-level units. The findings from simulation results demonstrate the effectiveness of the proposed strategy to provide fast and accurate fault detection and protection against all types of faults and locations in the ADN.

The Effect of Different Copper Discs on the Discharge of Superconducting Coils

High temperature superconducting (HTS) magnets often work at high energy density and have slow quench propagation speed, so a quench will present a serious risk to the safety of magnets. The quench protection method based on the dump resistance can effectively reduce the current and release the energy in the HTS magnets. However, too large dump resistance may cause excessive voltage across the magnets. A quench protection system consisting of dump resistances and metal discs has been proposed. Copper discs are often embedded in HTS magnets for conducting cooling and mechanical support. In the discharging process of HTS magnets, the copper discs can absorb energy from the magnets through magnetic coupling, thus accelerating the current decay of the magnets. This quench protection method is more effective than using dump resistance alone. In this paper, the effect of different copper discs on the discharging process of HTS coils is discussed. Eight types of copper with different residual resistivity ratios (RRR) are applied. The results show that with the increase of the RRR of the copper disc, the current decay rate of the coil increases, and the energy absorbed by the copper disc from the coil increases. The role of different copper discs in the fast quench protection of the coil can be sorted as: RRR = 300 > RRR = 100 > RRR = 80 > RRR = 60 > RRR = 40 > RRR = 30 > RRR = 20 > RRR = 10. The copper disc with RRR of 300 shows the best performance in quench protection of HTS coils.

A Fast Pilot Protection for DC Distribution Networks Considering the Whole Fault Process

To improve the consumption of renewable energy and to meet complex load demands. A model of a multi-terminal flexible DC distribution network with multiple overhead branch lines is constructed. Aiming at frequent non-permanent faults of overhead lines, a fast pilot protection scheme is proposed to cover the whole fault process. Using the hybrid DC circuit breaker (HDCCB) action as the boundary mark, the fast pilot protection can be divided into two phases: post-fault and fault restart. The first phase highlights rapidity, sending a trip command to HDCCB within 1-2 ms after the fault. The second stage emphasizes reliability, and points out that the data of the whole fault process should be fully utilized, and to fully excavate the characteristics of fault current. A multi-time scale and multi-criteria fusion protection scheme is proposed, which can effectively improve the reliability of fault area identification. Finally, a corresponding model was built based on PSCAD, a large number of simulation tests and robustness analysis proved that the proposed fast pilot protection scheme is feasible.

A Fast Short-Circuit Protection Method for SiC MOSFET Based on Indirect Power Dissipation Level

This letter proposes an indirect power dissipation level short circuit protection (IPDL-SCP) method for silicon carbide (SiC) metal-oxide semiconductor field-effect transistors ( <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s). Due to differences between normal conducting and short-circuit (SC) conditions, this method is triggered by the voltage oscillation <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ss</sub> at the parasitic inductance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ss</sub> ) of the source and directly monitoring <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> of SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> . For verification, the short circuit protection circuit is tested and proved functional on the SC test bench. Experimental results show that the protection circuit can respond to both hard switching fault (HSF) and fault under load (FUL), while the fastest response delays are 75 ns for HSF and 170 ns for FUL. Comparisons with other commonly used SC protection methods have also been made, which show that the proposed IPDL-SCP method has better performance in shorter protection delays.

Portable Heating System Based on a Liquid Metal Bath for Rapid PCR

With the outbreak of COVID-19 around the world, rapid and accurate detection of new coronaviruses is the key to stop the transmission of the disease and prevent and control the novel coronavirus, among which polymerase chain reaction (PCR) is the mainstream nucleic acid detection method. A temperature cycling device is the core of the PCR amplification micro-device. The precision of the temperature control and temperature change rate directly affect the efficiency of PCR amplification. This study proposes a new PCR method based on rapid PCR chip optimization of a liquid metal bath, which realizes precise and rapid temperature rise and fall control. We systematically explored the feasibility of using liquid metals with different melting points in the system and proposed a 47 °C bismuth-based liquid metal bath as the heat conduction medium of the system to optimize the system. The heat conduction properties of the thermally conductive silicone oil bath were compared. Compared with the thermally conductive silicone oil bath, thermal cycle efficiency is improved nearly 3 times. The average heating rate of the liquid metal bath is fast, and the temperature control stability is good, which can significantly reduce the hysteresis, and the temperature change curve is more gentle, which can greatly improve the efficiency of PCR amplification. The results of gene amplification using rat DNA as the template and SEC61A as the target also indicate that the system can be successfully used in PCR devices, and the types of PCR containers can be not limited to PCR tubes. Based on the experiment, we proved that the PCR method optimized by the liquid metal bath multi-gene rapid PCR chip can further improve the temperature response speed. It has the advantages of accurate data, fast response speed, low price, safety, and environmental protection and can effectively reduce the time of PCR and improve the application efficiency. As far as we know, this is the first international report on using a liquid metal bath to do rapid-cooling PCR.

Lassa-fever vaccine confers fast protection in animals

Lassa-fever vaccine confers fast protection in animals

Simplified protection algorithm for fault detection and localization in DC microgrid

In a microgrid, conventional overcurrent and current direction based protection techniques have limitations during high resistance faults. Besides, ring configuration microgrids offer bidirectional power flow rather than unidirectional power flow. Moreover, DC microgrids own low line resistance and high DC link capacitance; it results in an immense increase in current. During fault conditions, it may cause an undesirable disconnection of resources and make the system unreliable. An accurate and fast operating protection strategy is needed to explore and achieve the above mentioned challenges. To start, with the difference in consecutive current sample data, the current difference index has been evaluated. The non-zero index is granting the estimation of frequency using natural characteristics of fault current, which correctly discriminates an incipient fault and sudden switching loads. Thereafter, by adopting local voltage and current samples during the fault, estimated inductance has been exploited, which possesses polarity and magnitude to isolate the fault and identify the fault position, respectively. The proposed method genuineness for numerous cases like low and high resistance faults at various locations, including close-in faults, bidirectional power flow, different load conditions, and other configurations is validated in MATLAB/Simulink environment. This method precisely estimates fault location under the aforementioned cases. A comparative study of the proposed scheme with existing protection methods has been carried out, proving that this method is more accurate and enhances the relay dependability.

Characterization, signal estimation and analyzing of cold button BPMs for a low-[formula omitted] helium/proton superconducting LINAC

CAFe is a low-β helium/proton superconducting LINAC. It is as a demo LINAC for China initiative Accelerator-Driven System and constructed at the Institute of Modern Physics, Chinese Academy of Sciences. In this paper, an off-site characterization focusing on the capacitance measurements of cold button BPMs is presented firstly. Furthermore, a signal estimation and analysis of cold button BPMs is performed with regard to two kinds of beam commissioning, helium and proton beams. A good agreement between the calculation and the measurement proves that the developed theoretical model could accurately estimate the output signal of cold button BPMs. It considers the influence of low-β effect and long cable issues. Based on the transformation of the estimated signal from the time domain to the frequency domain, it is found that the amplitude spectra of cold button BPMs expand with the energy increasing and the bunch length shortening. The amplitude at the first harmonic frequency decreases, which causes the summed values from BPM electronics to be declined in the LINAC. However, the decline in summed values is not proportional to the decreasing of beam current. This is the reason why BPMs only give relative intensity and not absolute value for low-β beams when BPMs’ electronics using a narrow-band digital signal processing. These developments will be used for the cold BPM system and the fast machine protection system. It is dedicated to the driven LINAC of China initiative Accelerator-Driven System, which will deliver a 500 MeV, 5 mA proton beam in continuous wave operation mode.

Fault detection and classification of DC microgrid based on VMD

PurposeThis paper aims to present a new fault detection and classification scheme of both DC faults and AC faults on a DC microgrid network.Design/methodology/approachTo achieve reliable protection, the derivative of DC current signal is decomposed into several intrinsic modes using variational mode decomposition (VMD), which are then used as inputs to the Hilbert–Haung transform technique to obtain the instantaneous amplitude and frequency of the decomposed modes of the signal. A weighted Kurtosis index is used to obtain the most sensitive mode, which is used to compute sudden change in discrete Teager energy (DTE), indicating the occurrence of the fault. A stacked autoencoder-based neural network is applied for classifying the pole to ground (PG), pole to pole (PP), line to ground (LG), line to line (LL) and three-phase line to ground (LLLG) faults. The effectiveness of the proposed protection technique is validated in MATLAB/SIMULINK by considering different test cases.FindingsAs the maximum fault detection time is only 5 ms, the proposed detection technique is very fast. A stacked autoencoder-based neural network is applied for classifying the PG, PP, LG, LL and LLLG faults with classification accuracy of 99.1%.Originality/valueThe proposed technique provides a very fast, reliable and accurate protection scheme for DC microgrid system.

A new application for fast prediction and protection of electrical drive wheel speed using machine learning methodology

This paper introduces &lt;span&gt;a non-linear implementation of the speed control technique of permanent magnetic synchronous motors (PMSM) using electronic differential (ED) command. Artificial neural network (ANN) coupled with particles swarm optimization (ANN-PSO) are implemented to control wheel speed and steering angle. The main purpose of the PMSM system and its application is the command of electric vehicles (EV). In the controller design, three-phase currents and rotor speed shall be measurable and eligible for feedback. Our propulsion platform consists of two PMSM in the back. The study with implemented ANN-PSO is performed after collecting the data from the ED to manage the control of speed EV, Left and right of steering angle and steering ahead. Based on this strategy, a new application can be provided in the GPS application to give the information as input (curved path angle) to ANN-PSO. Next, the application of ANN-PSO can estimate the parameters of ED to avoid the slip, as well as improves better performance and dynamic stability of electric vehicle drive systems.&lt;/span&gt;

Transmission Line Distance Protection Algorithm Based on Bayesian Inference

This paper presents a distance protection method based on estimating the resistances and inductances seen by the relay using a least-squares (LS) approach combined with the application of Bayesian inference (BI) to determine fault probabilities in the protected zone over time. The use of BI in the presented algorithm increases the security and reliability of the LS-based line protection approach, which, although fast, may yield impedance estimates with numerical inaccuracies and therefore configures a solution capable of detecting faults internal to the protected zone rapidly and dependably. The authors tested the proposed algorithm using data sets obtained from transmission line fault simulations performed in Alternative Transients Program (ATP), which considered noisy measurements, current transformer (CT) saturation, capacitive-coupling voltage transformer (CCVT) transients, switching onto fault, close-in faults, frequency variations, uncertainties in the line’s parameters, and power swings. Furthermore, the authors tested the presented method against measurements recorded by field protection equipment during seventy-nine actual fault events on four existing 500 [kV] lines. The results indicate that the proposed algorithm is a fast, secure, and reliable distance protection solution and that using BI to the LS-based distance protection approach increases security while maintaining fast fault detection.

Hilbert–Huang transform and decision tree based islanding and fault recognition in renewable energy penetrated distribution system

A fast protection algorithm based on Hilbert–Huang transform (HHT) is proposed in this paper for islanding and fault detection, classification, and location in a distribution system penetrated by a solar renewable energy source. The three-phase current signals measured at the substation are utilized to extract the instantaneous features from the first level residue using Hilbert Transform (HT) after empirical mode decomposition (EMD). The feature indices computed per phase for each event using minimum post-disturbance data are then fed to a decision tree machine learning (DTML-1) model to classify disturbances into four classes: normal, fault, islanding, and switching transient. Once a fault is determined, another DTML-2 model classifies the fault into one of the seven types of faults, namely 3P-ABC (three-phase faults), 2P-AB, 2P-BC, 2P-AC (two-phase faults), 1P-AG, 1P-BG, and 1P-CG (single-phase faults). Subsequently, seven DT models based on the fault type locate the IEEE 13 bus system’s zone of fault. Variations in noise levels, DG capacity, and fault incidence angles test the proposed algorithm to achieve a good accuracy level in less time. Switching transients like capacitor switching, feeder on/off, and transformer excitation/de-excitation are also successfully classified within a quarter cycle contaminated with noise levels of 20 dB SNR.

A Hybrid Time-Domain Protection Scheme for Series Compensated Transmission Lines

In this paper, a hybrid time-domain protection scheme for series compensated lines using incremental quantity combined with traveling wave principle is proposed. Each principle is assigned a zone of the protected section of the line to achieve fast protection. The incremental quantity-based method is assigned for close-in faults up to 35% and the traveling wave from 33.33% to 66.67% of the line from the relay end. The incremental quantity-based method compares a dynamic restraining quantity obtained from voltage and current to the operating quantity using current for the protection decision. The traveling wave-based method derives a decision by comparing the calculated line length, obtained using the first three arrival times measured at the relay location, to the actual line length. The proposed hybrid approach exploits the advantages of both principles to achieve better reliability and speed of protection for series compensated transmission lines. The proposed scheme is verified for a 400-kV, 300 km series compensated transmission line and results are compared with traditional impedance and incremental quantity-based methods.