High Voltage Relays Research Articles

Reconsideration of energy measurement of spark discharge using different triggering methods and inductance loads

A series of electrostatic sparks at different energies are triggered by different methods in testing the minimum ignition energy (MIE) of dust clouds. It is necessary to investigate the difference between actual spark energies and MIEs under different triggering methods. A multi-energy spark generating circuit combined with high-voltage relay (HVR) triggering and electrode movement (EM) triggering was set up to study the effects of triggering types and inductance loads. The first current peak was proposed together with damping ratio and angular frequency of spark current to evaluate the reliability of the experimental results. Results showed that the deviation of spark energy release efficiency between the two triggering types is about 5%–25% when the storage energy was 34 mJ, 110 mJ, 340 mJ and 1100 mJ, which was not enough to cause the difference in the magnitude of MIE. The MIEs of clouds of lemon powder and sea buckthorn powder are consistent using the two triggering types. But the MIE of clouds of lycopodium triggered by EM without inductance is higher than that triggered by HVR. It indicates different triggering types may lead to different MIE results when testing fine dust even if the actual released energy is almost the same. The spark energy release efficiency without inductance is greater than or equal to that with inductance. However, the MIE of lycopodium clouds dropped from 75–90 mJ with no inductance, to 8–10 mJ with a 1 mH inductance. The MIEs of clouds of lemon powder and sea buckthorn powder showed similar trends.

An Improved Air-Core Coil Sensor With a Fast Switch and Differential Structure for Prepolarization Surface Nuclear Magnetic Resonance

Surface nuclear magnetic resonance (SNMR) technology based on a prepolarization field is a new geophysical method that offers a higher resolution for detecting shallow groundwater than traditional SNMR. However, when a prepolarization SNMR system works in noisy environments (such as cities), it is difficult to obtain high-quality data because of the low signal-to-noise ratio (SNR). Moreover, a traditional air-core coil sensor system has a relatively large dead time, which can cause early signal loss and further reduce the SNR. To solve these problems, we proposed an innovative air-core coil sensor design method to improve the detection capability of prepolarization SNMR in complex noise space. To suppress environmental noise and increase the signal amplitude, a passive matching network based on a differential structure was designed, which has a gain of 9.69 dB and a bandwidth of 700 Hz. In addition, a fast switch based on back-to-back technology was also used to replace the mechanical high-voltage relay, and the switching time was reduced to less than $10~\mu \text{s}$ . The effectiveness of the new sensor was tested via experiments in the laboratory and field. The test results showed that the switching speed between transmitting and receiving is thousands of times faster than that of the traditional sensor, and the new sensor can still detect effective free induction decay (FID) signals in a noisy environment where the traditional sensor completely fails. Therefore, this research can effectively improve the SNR and provide strong support for the application of prepolarization field magnetic resonance technology in areas with complex noise environments.

Self-restrained energy grid with data analysis and blockchain techniques

ABSTRACT Efficient energy distribution and utilization play a significant role in the energy grid, especially with renewable sources. The existing grid system has problems in resource utilization, data privacy, wireless communication, and dynamic demand handling. An energy grid is proposed based on IoT, blockchain, and machine learning techniques to solve the problems. The proposed energy grid architecture controls energy flow according to the demand, predicts expected load, analyzes consumer behavior, and enables the users in the grid trade energy in peer to peer manner. Energy flow in storage modules controlled with high voltage relays, and it automates the charging and discharging of respective battery pools in the grid. Energy consumption and battery status in the grid uploaded to the distributed file system. The data clustering model deployed in the server analyses those data and divides the consumers into three groups according to the consumer’s consumption behavior: high, moderate, and low consumption. The Time series analysis model deployed to forecast the load and predict peak hours. The codes deployed as a smart contract in an Ethereum blockchain platform. Machine learning algorithms are deployed for forecasting and clustering. In forecasting, the average error rate is 37% less than other generally used algorithms, and in the clustering algorithm, the accuracy increases as the dataset increases, which is 30% more than other cluster models. The controlled energy storage model in this grid provides up to 500–600 extra charge cycles for batteries than other traditional methods. The distributed IPFS storage provides data security, and smart contracts support grid operational security and data privacy. The data analyzation module of the grid helps effective resource utilization.

Smart Internet of Isolated Capacitor Trip Device for High-voltage Protective Relay of Backup Power

Smart Internet of Isolated Capacitor Trip Device for High-voltage Protective Relay of Backup Power

High voltage electrical system of 8.56 GHz CW klystron for electron cyclotron heating on QUEST spherical tokamak

A high voltage DC power supply for the cathode of the 8.56 GHz CW klystron has been set up for electron cyclotron heating (ECH) in steady state tokamak operation on QUEST spherical tokamak. The power supply is equipped with an IGBT array and a reactor for fast shutoff of the voltage in 10 μs, where the influx of electric energy at the short circuit is limited to 5 J. AC switches also have been installed in the three-phase power lines. High voltage relays are useful to save electric energy consumption. Fast three-phase AC switching by IGBT-stack is applicable to reduce the electric load of the components of the klystron power supply.

INFLUENCE RESEARCH OF CHEMICAL COMPOSITION OF HIGH-VOLTAGE CIRCUIT DESIGNS ON THE FIRE BREAK-OUT AT THE LOCOMOTIVES

Purpose. The work is aimed at identifying the influence of the incompatibility of chemical composition of the high-voltage circuits designs on the mechanism of fire break-out at the VL-80k locomotive. Methodology. Macro- and microstructural, fractographic, analytical analyses were applied during the research of the samples of contact clamps materials. Findings. Analytical analysis of the parts of electric locomotive made it possible to identify the primary causes of circuit-breaker oil ignition followed by a complete burnout of the locomotive section. It was established that the destroyed contact clamps had a chemical composition that does not meet the requirements of design and technical documentation. The arc formed between the edges of macro-cracks during the destruction of the contact clamps did not lead to the disconnection of the main high-voltage relay, and due to the high power contributed to the ignition of a large amount of circuit-breaker oil, which was located below the contact clamps. Such ignition may also occur as a result of the weakening of the locomotive power circuit caused by the vibration. One can prevent such cases of ignition by identifying critical heating temperatures of the contacts of high-voltage cabinet, contactor and resistor groups to immediately strengthen or replace the connection. Originality. A comprehensive analytical and technical approach was applied in identifying the causes of fire at the VL-80k electric locomotive. A typical fire break-out mechanism and a maximum number of factors that could affect the premature destruction of the contact clamps were investigated. It is shown that a set of factors that negatively affected the performance characteristics of the contact clamps, simultaneously reached the so-called "critical mass" as a result of heating of these defective parts. The introduction of additional signaling factors for supercritical heating of the investigated and other important parts and designs of locomotives will prevent fires at the locomotives. It will help timely to identify the inconsistency of the chemical composition of the parts of the design and technical documentation, as well as to find out the gaps in the electrical connections that were formed either due to the insufficient tightening, or due to the weakening of connections in the process of vibration during the movement of locomotives. Practical value. The proposed additional signaling will contribute not only to the preservation of the locomotive fleet of Ukrzaliznytsia OJSC, but also to the rescue of locomotive brigades.

Simultaneous Determination of Inorganic Cations and Anions in Microchip Electrophoresis Using High-voltage Relays.

A new and simple method for the simultaneous determination of cations and anions by microchip electrophoresis with capacitively coupled contactless conductivity detection (ME-C4D) is described. The best analytical performance was found by applying a sinusoidal wave with 800 kHz frequency and 20 Vpp amplitude. An optimized background electrolyte (BGE) composed of 20 mM His/MES and 0.01 mM CTAB was chosen for the simultaneous analysis. Samples containing K+, Na+, and Li+ as the cations and Cl-, F- and PO43- as anions were analyzed simultaneously in a single run (within 3 min). The reproducibility obtained by the method was compared with those obtained in previous studies that had employed simultaneous analysis of anions and cations by ME-C4D. The proposed simultaneous determination method is inexpensive, simple, fast, easy to operate, and offers a high degree of integration.

Building Principles of High Voltage Relay Protection

Building Principles of High Voltage Relay Protection

Inboard/outboard plasma actuation on a vertical-axis wind turbine

Vertical axis wind turbine (VAWT) blades can experience large positive and large negative angles-of-attack that produce both inboard and outboard dynamic stall. Dielectric barrier discharge (DBD) plasma actuators can control dynamic stall and hence an inboard/outboard switching control technique was developed where encapsulated electrodes were deployed on either side of the blades of an H-rotor turbine. An electromechanical system, including a shaft-mounted micro-switch and high-voltage relays, was developed for the purpose of earthing the inboard encapsulated electrode of the upwind blade with the outboard encapsulated electrode of the downwind blade. The actuators were connected to a high-voltage source via slip-rings and were pulse-modulated to exploit flow instabilities in an on/off feed-forward configuration. Turbine performance measurements showed that switching produced slightly larger improvements than either inboard or outboard actuation alone. The modest differences were traced to weak plasma being generated over the floating encapsulated electrodes, whose source was unavoidable slip-ring conductor proximity. Elimination of the floating electrode plasma resulted in larger performance increments for inboard versus outboard actuation due to the larger dynamic pressure relative to the blades in the upwind swept area of the turbine compared to that in the the downwind swept area.

Quasi-balanced two-wave mixing interferometer for remote ultrasound detection

We present an improved detection scheme for a two-wave mixing interferometer with a Bi12SiO20 crystal. The proposed detection scheme allows quasi-balanced detection of ultrasonic signals whereby electrical disturbances are suppressed. Quasi-balancing is achieved by changing the polarity of the high voltage at the photorefractive crystal, leading to an inversion of the optical interference signal, in combination with inversion of the detector signal using a signal inverter before the data acquisition device. The polarity of the high voltage is changed by utilizing an H-bridge consisting of five high-voltage relays. Microcontrollers are used to synchronize the reversion of the high voltage at the photorefractive crystal and the inversion of the measured signals. We demonstrate remote measurement of ultrasonic waves and shown that electrical disturbances are suppressed using the quasi-balanced mode.

Compact, high voltage power supply for the lab-on-a-chip.

The design, construction and operation of a simple, inexpensive and compact high voltage power supply (HVPS) for use in conjunction with a simple cross capillary electrophoresis microchip is presented. The microchip HVPS utilizes a single high voltage power supply (15 kV), a voltage-divider network, to give the voltages necessary to operate a gated injection valve, and two high voltage relays for switching between the open and closed gate sequences of the injection. In order to accommodate the application of different simple cross microchip dimensions, a set of equations for defining the resistor network and ensuring proper gate performance are presented.

Versatile 3-channel high-voltage power supply for microchip capillary electrophoresis.

The fabrication of a battery operated 3-channel high voltage power supply for microchip capillary electrophoresis is described. The power supply consists of two positive and one negative DC-DC converters, a microprocessor controlled timer, a battery and a transformer to recharge the battery and feed the high voltage relays. This arrangement allows the possibility to control the potentials applied in the 0 to +/-4000 V range to a variety of microchip setups. It can also be easily adapted to perform either gated or pinched injection. The inclusion of a rechargeable battery was adopted to feed the DC-DC converters to reduce noise levels and achieve portability.

Minimizing the Number of Voltage Sources and Fluid Reservoirs for Electrokinetic Valving in Microfluidic Devices

A microchip gated valve is demonstrated that uses a single voltage source and three fluid reservoirs. The fluidic valve is a cross intersection, and the channels are dimensioned to perform the appropriate voltage division, simplifying the voltage control hardware. A single voltage source is applied directly to the sample reservoir and through a high-voltage relay to the buffer reservoir, and the waste reservoir is grounded. The volume of sample dispensed is determined by the duration that the high-voltage relay is open. Volumetric reproducibility is demonstrated to be <0.5% relative standard deviation for volumes of ≥20 pL. The valve is tested for the minimum applied voltage necessary for leakage-free operation, i.e., sample diffusing from the cross intersection into the analysis channel. Moreover, appropriate channel dimensions are used to minimize the number of fluid reservoirs allowing effluent from the analysis and waste channels to be combined into a single reservoir.

An integrated microfluidics-tandem mass spectrometry system for automated protein analysis.

We describe an integrated analytical system consisting of a microfluidics device micromachined using photolithography/etching technology, a panel of computer-controlled high-voltage relays, and an electrospray ionization tandem mass spectrometer. Movement of solvents and samples on the device and off the device to the mass spectrometer was achieved by directed electroosmotic pumping induced by the activation of a suitable constellation of high-voltage relays. The system was used for the sequential automated analysis of protein digests. We demonstrate low femtomole per microliter sensitivity of detection and compatibility of the system with the automated analysis of proteins separated by two-dimensional gel electrophoresis.

Studies of Laser-Metal Interactions using a Coupled Laser-SEM System

With the advent of new high-power laser systems and the increasing variety of scientific, commercial, and military applications, a more detailed understanding of laser-metal interactions is required. Of particular importance are the induced surface damage, plasma-plume diagnostics, shockwave initiation, and internal structural damage during high-power pulsed laser loading.In the present program, a Cambridge scanning electron microscope (SEM) has been modified to accept a focused laser beam into the sample cavity. An external high voltage relay, triggered from the frame generator at the start of the laser pulse, provides a finite time lag of 50 to 100 milliseconds before the onset of framing.

High voltage relay

High voltage relay