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A generator of high-power nanosecond pulses is described that contains a high-voltage unit, which is based on a magnetic-compression circuit and a diode current interrupter, and a high-voltage transistor unit, which provides high-efficiency energy switching to the high-voltage unit. The results of using this generator in an experimental plasma installation that was developed for studying the possibility of synthesizing silicon from a mixture of H2 and SiF4 are presented.

The time shift of mechanical watches is caused by individual differences (manufacturing error), environmental temperature, magnetism, posture, impact force and dynamic environment. The easiest and clearest method of measuring the accuracy of mechanical watches is to measure the time shift by comparing it with the reference time. The disadvantage of this method is that it can only measure accuracy at a certain time. Another method for measuring the accuracy of mechanical watches uses a watch timing machine that obtains the vibration sound of a watch using a microphone and calculates accuracy in the short term. This method can measure the change in watch accuracy over time. However, it cannot be used to measure accuracy in a dynamic environment because the watch timing machine is large and there is a sound noise. To clarify the accuracy of mechanical watches in dynamic environment, this study developed an accuracy measurement system which can be carried and measure in a dynamic environment. This study monitors the movement of a partly constituted mechanical watch using a photo interrupter and develops a method to calculate the rate and amplitude of a balance wheel from the output value of the photo interrupter. The validity of the developed system is verified by comparing the time shift of the system and radio clock time over the long term. The developed system, can be used in a dynamic environment because it consists of the photo interrupter in the watch case. Moreover, this study conducted measurements under forced vibration using vibration generator and during walking with the system.

The evolution processes of vacuum breakdowns in single- and double-break vacuum interrupters are reported in this paper, in order to reveal the formation mechanisms for the conductive channels in vacuum arcs. Breakdown experiments in two vacuum interrupters containing 10–30 mm gaps with single-break and double-break are studied. The light emission during breakdowns is observed by an intensified charge coupled device camera, with the current and voltage waveforms being recorded simultaneously. According to the results, there is no difference between the evolution processes of breakdowns in small gaps and large gaps. The establishment of the conductive channel and sustaining of the vacuum arc can be achieved by the effect of the cathode without any contribution from the anodic glow. In the double-break interrupter, the transition from insulation to conduction for the two serial connected gaps starts simultaneously but evolves independently.

The article describes a measuring complex based on the 32-bit STM32F103VET6 microcontroller for studying the lux-ampere (light), frequency and inertial characteristics of a photoresistor with different laws of recombination of nonequilibrium charge carriers arising under the influence of light. The developed complex is connected to a personal computer (smartphone) and allows to analyze the rise and fall edges of the photoresistor current, as well as to determine the lifetime of excess charge carriers at different illumination levels. Unlike traditional methods for measuring the parameters of photoresistors operating in a dynamic mode, the proposed measuring complex does not use an oscilloscope and a separate modulator of the luminous flux (generator or light interrupter), this made it possible to significantly reduce the size and cost of the complex, as well as automate the measurement process. To determine the frequency response of the photoresistor, it is proposed to use a frequency synthesizer, which allows, together with a digital-to-analog converter of the microcontroller, to form an amplitude-modulated light flux of the required frequency and modulation depth. The complex described in the work can be connected to the Internet using a Wi-Fi module based on an ESP8266 microcontroller, which allows conducting research in a remote mode. It is also possible to determine the parameters of the photoresistor at different values of the load resistance.

Nowadays, high voltage circuit breaker (CB) simulations are mostly based on Computational Fluid Dynamics (CFD) models. Such simulations require significant computer resources. An alternative approach is to use enthalpy flow models, which do not use space discretization of the interrupter unit chambers and valves. Gas flow is calculated based on state of gas in adjacent chambers and valve settings. However, the valve shape has significant influence on the effective flow cross section between chambers. Therefore, in order to ensure correct simulation results, it is necessary to determine the correct values of discharge coefficients for all valves in the interrupter unit of a circuit breaker. In this paper, the discharge coefficients were determined by combining a series of CFD and enthalpy flow simulations for each valve in the interrupter unit. After that, discharge coefficients are used as input for further simulations based on the enthalpy flow model. This way, benefits from both models are combined: more precise gas flow calculation and faster simulations. The proposed novel approach is validated in a high-power laboratory by pressure measurements on a 420 kV 63 kA self-blast circuit breaker.

The medium-voltage dc (MVDC) interruption technology has grown in recent years, driven by increased interest in using MVDC system for integrating distributed renewable energy and improving the efficiency of power supply. In this paper, two topologies of current injection MVDC breaker are focused on. The first topology is based on conventional precharged capacitor that utilizes a bridge-type commutation branch to realize the freewheeling for the interrupter and bidirectional breaking. With the help of simulation, the effect of stray inductances on the current commutation capability is analyzed in detail, and then, a prototype of the MVDC breaker is built to test the fault current breaking performance. The second topology is an improved MVDC breaker based on magnetic induction current commutation module (MICCM). With MICCM analyzed carefully in terms of circuit and structure parameters for determining their optimal values, the prototype of the improved 10-kV dc breaker is built and tested, which validates the feasibility and effectiveness of improved topology.

We know that solar heat can be used as one of the natural resources that are still very abundant on earth and can be used as a new source of energy or better known as solar cells and power plants that use solar cells are generally still static. Therefore we need a mechanical system that can move the position of the solar panel so that it can move according to the position expected by the use of solar panels to get energy from the sun. Arduino Uno serves as the control center of all systems built and tools. in moving the solar panel using Askremote control to give orders to the L298 module as a controller of the dc motor so that the dc motor can move according to the design and construction of the system embedded into the Arduino and the Photo Interrupter functions as a barrier to the movement of the dc motor.

This paper presents results of experimental studies the effect of changing operating temperature on the operating mode of thyratron-type gas-discharge current switches in a scheme with inductive energy storage. Analysis of the obtained results made it possible to establish that the average settling time in the continuous-frequency mode for such type of switches is 20–25 min. Based on the distributions of the surface temperature on the functional units of the devices over time, it can be seen that the degree of anode, grid and cathode nodes heating increases towards the anode node at U m ≥30 kV, at U m ≤30 kV heating degree increases towards the grid and cathode nodes, due to changes in the ratio of switching losses and conduction losses. In the new gas- discharge current interrupter, it was possible to reduce the heating of the grid node by an average of 15-20%, while a temperature change by 70°C leads to a 2-fold increase in a critical charge.

W artykule opisano autorski sposób pozwalający na określenie rzeczywistej wartości ciśnienia w próżniowej komorze rozłącznikowej SN podczas wysokonapięciowych badań laboratoryjnych. Konieczność opracowania metody tego typu wynikła z braku możliwości pomiaru ciśnienia bezpośrednio w komorze próżniowej w trakcie badań. Istniało bowiem ryzyko uszkodzenia próżniomierza w wyniku przeskoku elektrycznego. Proponowana metoda polega na pomiarze w warunkach beznapięciowych różnicy ciśnienia pomiędzy zestawem pomp próżniowych, a prototypem komory próżniowej wykonanym dla potrzeb realizacji tej metody. Dzięki temu znając wartość ciśnienia przy pompach oraz mając wyznaczone charakterystyki skalowania układu, w trakcie badań wysokonapięciowych możliwe będzie określenie rzeczywistego ciśnienia wewnątrz badanej rozłącznikowej komory gaszeniowej SN. Przeprowadzono pomiary spadku ciśnienia w kanale pompowym dla powietrza oraz trzech gazów elektroujemnych: helu, argonu oraz neonu, wykorzystywanych w badaniach przez autorów niniejszego artykułu.

This research paper presented a design that will address the challenges brought by remanence in ground-fault current interrupter devices (gfci). Remanence or residual magnetism is the magnetization left behind in a ferromagnetic material (such as iron) after an external magnetic field is removed. Remanence will make the gfci devices less accurate and less reliable in tripping the current above threshold in just five (5) years. It affects the performance of the device in terms of efficiency, accuracy, and response time. In this research, the problems caused by remanence were alleviated by using two identical transformers in detecting residual current both for hot and neutral wires. The difference of the current detected by the two transformers will be the basis of the signal threshold in tripping the device. By doing so, the problems caused by remanence phenomenon will be solved without compromising the response time of the circuit which is around 16 mS. The design will extend the life span of GFCI devices up to 15 years.

The arc temperature profile in an interrupter, which determines the extinguishing characteristic of an SF6 circuit breaker (CB), is of interest to designers and developers. In this investigation, optical fibres and spectrograph were employed to measure the arc temperature profiles in a 252 kV SF6 CB during short current interrupting. The temperature profiles of the upstream, throat, and downstream of the nozzle have been measured. The optical fibres can transfer the arc light from the measuring points in the nozzle to the spectrograph. Moreover, the spectral line intensities of copper (Cu) 510.5, Cu 515.3, and Cu 521.8 nm were obtained by the spectrograph. The condition in CB can be treated as a local thermal equilibrium system, and the temperature profiles can be calculated by two-line method and Abel inverse method. The arc temperature profiles of the interrupter under 15–50 kA root mean square current have been analysed through the method established in this investigation.

This paper investigates the dynamic dielectric recovery synergy (DDRS) of hybrid circuit breakers (HCBs) with CO2 gas and vacuum gaps in series. The interaction between the vacuum arc and CO2 gas arc is simulated by the continuous transient arc model and Mayr arc model. The simulation results indicate that the extra methods, for example, dividing capacitors, are needed to obtain optimal DDRS of HCB. The prototype of HCB and the test circuit are established. The influence of the coordination of arcing time, dividing capacitors, and the CO2 gas pressures on the transient recovery voltage (TRV) distribution and the breaking capacity is investigated. The differences of HCBs with SF6 gas and CO2 gas are also compared. According to the results, favorable DDRS in HCB can be obtained in the condition that the vacuum gap endures the initial TRV while the following major TRV distribution is mainly depended on the dynamic dielectric in CO2 gas gap. However, the dynamic dielectric recovery of CO2 gas gap is limited by the structure of rotating arc CO2 gas interrupter in this paper. In the future, the interruption capacity of HCB based on CO2 gas can be improved by synergy control, as the development of CO2 gas circuit breakers.

To guarantee the uniform distribution of transient recovery voltage for double-break circuit breaker, grading capacitors are often installed in parallel with each interrupter unit. In this study, the influence of the capacitors on the secondary arc is systematically investigated. First, the equivalent circuit for ultra high voltage transmission line is developed. Taking the capacitor into account, the formulas for the arc current and the recovery voltage, not only the steady state but also the transient, are derived. Meanwhile, the dynamic models for primary arc and secondary arc models have been established in the environment of EMTP. Then, a series of simulations have been performed. The impact of the capacitor on the key quantities of secondary arc, such as the rate of rise of recovery voltage, the arcing time, and the maximum instantaneous current, is comparatively analysed. Furthermore, the capacitor can be extended to suppress the secondary arc, and a novel method is proposed in this study. The operating principle of this method is presented, and its effectiveness is validated through electromagnetic transient simulations. For practical implementation, the technical requirement is finally discussed. The proposed method is simple in structure, and it provides an alternative to the neutral reactor.

A high power laser energy interrupter is investigated and developed. The micromachined laser interrupter is a critical component of the MEMS based safety and arming (S&A) system, which acts as a switch to selectively couple optical power between input and output fibers using direct coupling technique. The switching of high power laser energy is demonstrated by taking advantage of direct thermal actuation of cantilevered large-core multimode fibers. Models describing the combined electrothermal and thermomechanical characteristics of the thermal actuators are developed with temperature-dependent parameters. The temperature distribution of the actuator is investigated, and the influence of the actuator’s geometrical parameters on its force and displacement is analyzed. Actuator displacement versus drive current is found to be in good agreement with model predictions. Switching time is 19 ms from the safety to the arming state with a maximum operational frequency of 34 Hz. Optical efficiency is predicted and a series of tests are conducted to measure transmission efficiency of the laser interrupter. The optical efficiency is found to be about 92.7% with a maximum power transfer of 2780 mW from a 3000 mW input, and the channel isolation is 57 dB.

In order to meet the special requirements of the ultra-high voltage (UHV) high-speed bypass switch, the structure of the operating mechanism needs to be re-optimized. The target parameters of the operating mechanism are analyzed in this paper. Combined with the mechanical structure and load characteristics of the bypass switch, the permanent magnet brushless DC motor operating mechanism is designed. The parameters of the stator, electric load, magnetic load, pole pair number, air gap, pole arc coefficient and slenderness ratio are optimized. The simulation results show that the permanent magnet brushless DC motor can realize the opening and closing operation of the bypass switch and meet the speed characteristic requirements of the SF6 interrupter, which verifies the rationality of the design.

The modification of rotor-pulsation machine – pulsation machine with a vibrating rotor (PM with VR) has been researched in the work. Rotor in such modification not only rotates but also oscillates axially with the frequency about 3000 min-1 and amplitude 0,5–1,0 mm. The aim of this research was to define specific features of milk homogenization process in PM with VR and disperse characteristics of milk emulsion. Analytical researches resulted in finding dependence of milk emulsion acceleration as a main factor of milk fat particles breakup subject to the design and kinematic parameters of PM with VR. Experimental researches were carried out on the laboratory setup of the pulsation machine with a vibrating rotor which was designed by the authors. The subject of experimental researches is cow's milk. The sizes of milk fat globules after homogenization were measured by the optical microscope equipped with a digital camera. The researches resulted in defining characteristics of milk emulsion dispersing in PM with VR. Thus acceleration grows when diameter, oscillation amplitude and rotation frequency of the rotor are increased, and channels length of the rotor and stator, the gap between them are decreased and the number of rotor openings is 4 or less. Empirical dependence between the average diameter of the fat globule (0,7–1,9 μm) and the average emulsion acceleration ((1–10)·103 m/s2) in the interrupter of PM with VR is defined which proves that the emulsion flow acceleration is the main cause of homogenization of PM with VR with 92 % confidence. High quality of the milk emulsion after processing in PM with VR has been proved. The crankshaft rotation frequencies up to 2880 rpm and rotor oscillation amplitude of 1 mm enable to receive milk emulsion with the average dispersion about 0,8 μm that corroborates using PM with VR in the industrial conditions for milk homogenization to be perspective.

Application of a dc circuit breaker (DCCB) using superconducting current-limiting technology can strongly reduce the short-circuit currents that occur in high-voltage dc systems. The superconducting current-limiting-type DCCB includes a superconducting current-limiting module and an interrupter module (IM). The objective of this paper is to determine the effects of the quenched resistance characteristics of the superconductor on dc interruption based on the self-excited oscillation principle. We test the quenched resistance characteristics and the recovery times of two different types of YBCO-coated conductor tapes (with critical currents of 102 and 225 A). The quenched resistance of the 102-A YBCO tape was quenched more rapidly than the 225-A tape, and the quenched resistance of the 102-A tape was higher than that of the 225-A tape. Therefore, the 102-A tape can limit the fault current to a lower level, which results in the reduction in the difficulty of interruption for the IM. The arcing time, the absorbed energy, and the peak current in the ZnO arrester of the IM can also be reduced considerably because the interrupting current is much lower.

Interruption tests were conducted using the same circuit breaker for an initial pressure of SF6 0.5 MPa (gauge pressure) and CO 2 mixture 1.0 MPa, 0.8 MPa, and 0.6 MPa. The pressure-rises in the compression and thermal expansion chambers were measured for verifying the computational results using a simplified synthetic test facility. Further, the possibility of the CO 2 mixture substituting SF 6 gas was confirmed. Moreover, in view of the thermal recovery capability, it has also been confirmed that the pressure of the CO 2 mixture can be reduced almost to the same value as that of the SF 6 gas by optimizing the design parameters of the interrupter.

In order to find the synergy of double-break vacuum circuit breakers (VCBs), we conducted a synthetic test including different vacuum gaps, different type electrodes, and different grading capacitors. The double-break VCBs are composed of Axial Magnetic Field (AMF) and Transverse Magnetic Field (TMF) contact VCBs, which can constitute four combinations. The optimal combination of AMF and TMF type electrodes was obtained by comparing with the breaking capacity and voltage distribution of the four combinations. The breaking capacity of double-break VCB with AMF and TMF type electrodes in series while the AMF interrupter is on the lower side is largest because the voltage distribution is the most even which is caused by the different equivalent capacitances of different interrupters. The optimal matching vacuum gaps of the best combination were obtained by a synthetic test of different vacuum gaps, which may make the grading capacitors of double-break VCBs small, even obsolete. The combination of maximum breaking capacity was series AMF type interrupters with suitable grading capacitors of 500–2000 pF. The experimental results provide the best combination and matching control mode for VCBs with double-break.

The unique selling propositions for a vacuum interrupter (VI) are its compactness, negligible maintenance and a high degree of reliability. The on-site reliability of a VI primarily depends on its vacuum level in addition to the breaker and site conditions. The vacuum level i.e. the pressure inside the VI should be below a certain threshold during commissioning and also during its entire service life. As the VI is a sealed-off device, direct measurement of the pressure is not possible. Hence an inferential method called as inverted magnetron is employed for this purpose. This method measures the ion current through the interrupter on the application of a high voltage across the open gap and a magnetic field. This ion current in turn is correlated to the pressure inside the VI. While the magnitude of the ion current gives the pressure at the particular instant, the nature of the waveform throws light on kind of gases present inside the VI. This information could help us predict the mid to long term performance of the vacuum interrupter. The paper highlights this very aspect of the inverted magnetron measurement which could be used to assess the long term reliability of the vacuum interrupters.

The emission of contact material into the vacuum inflicted by switching operations of vacuum interrupters (VIs) is crucial for both, the metal coating of inner surfaces and the space and time depending vapor pressure in the tube chamber, having impact on the interrupter's withstand voltage and its maximum switching ratings, respectively. In this paper we describe a code that is capable to calculate the metal vapor expansion and its deposition on the inner surfaces by means of an OpenFOAM®-implementation of the Direct Simulation Monte Carlo (DSMC) method. We compare simulation results with those gained from switching experiments and present possible model improvements.

A concept for a dc circuit-breaker is proposed. A vacuum interrupter is used together with a resonant circuit excited by a power electronic converter to create a zero-crossing in the interrupter current. A low amount of semiconductor devices is needed because they perform repeated switching operations during current excitation. Tests have been performed with a prototype interrupting 10 kA against 9 kV in 3 ms.

In this article, large capacitor charging and discharging experimental system is utilized to generate 270V DC-current by pre-charging to the large capacitor and discharging. Interrupter switching experiments of 540A, 1800A are done in aviation environment, and results of arcing breakdown manner are analyzed and explained. The experiment results indicate that 270V DC-current and arc in aviation environment can be broken by the way of using IGBT in appropriate time; In aviation environment, the breaking capability can be improved, and arcing breaking manner can be used to estimate the arc time constant by several experiments.

In recent type tests, a 252kV SF6 self-blast circuit breaker re-ignites several times after interruption. In order to solve this problem, through CFD simulation of the gas flow field in the interrupter on load, the pressure, temperature and velocity after current zero are analyzed carefully. The conclusion is that, due to the upstream pressure decreased quickly after current zero and will lower than downstream pressure, the downstream hot gas returns to the upstream resulting in the re-ignition. Based on CFD simulation two optimal structure is proposed, and is verified by simulation.

In order to research the interruption process of vacuum circuit breaker in aviation intermediate-frequency (360Hz∼800Hz) power supply system, vacuum arc experiments are carried out in interrupter with the diameter being 41mm and with the contact material being CuCr50 alloy. It can be indicated from the results as follows: With the increase of frequency and peak value of the current, both the peak value and the rise rate of the intermediate-frequency vacuum arc voltage increase, and the interruption ability decreases. However, the erosion of contacts is weaker for a shorter arc time, comparing to the power frequency current in the same value. When the vacuum arc reignites0, metal droplets are emitted from the contacts. The drive force is from the center of the contact to edge. If the density of plasmas and metal vapors and the numbers of the metal droplets come to a certain level, the arc may be broken down, which cause the interruption failed.

Recently, the self-blast principle of extinguishing the arc by the blast pressure which is generated by the arc itself has been widely applied to the high voltage circuit breaker. In the self-blast principle, the pressure relief valve fitted on the piston is opened to release excessive pressure in the compression volume during high current interruption. The design of the pressure relief valve operation is important for the performance of self-blast interrupter. Practically, the pressure relief valve is actuated by spring force and designed to open when the overpressure becomes greater than the designated operating pressure difference. In this paper, the actual pressure measurement result of the compression volume to understand the movement of the pressure relief valve are presented. The analytic model which describes the movement of the pressure relief valve are proposed, and the effects of different pressure relief valve models are analyzed by gas flow simulation tools.

Aiming at the phenomenon that the arcing time is different when SF6 circuit breaker interrupts capacity current under the conditions of positive and negative polarity. So the capacity current breaking test by SF6 circuit breaker is used to study it, which can provide reference for the optimization of SF6 arc extinguishing chamber. In this paper, the interrupter structure of test prototype is introduced. Electrode reversal is analyzed when the static parts of SF6 circuit breaker is connected with capacitive loads. According to CB2 in GB 1984–2014, The back-to-back switching capacitor group test is completed in the 40.5kV SF6 self-circuit breaker prototype. Opening speed of test prototype is 3.85m/s. The main test parameters are as follow, closing surge peak is 26kA, inrush frequency is 4050Hz, the valid values of opening current is 826A. In the condition of positive and negative polarity, 83 times CO operations are completed in test prototype. The test result is that restrike did not occur. When the static part of breaker is connected with capacitive loads, the short arc time under the negative polarity condition is longer than that of the positive polarity. And the short arcing time is 0.9ms and 1.6ms, respectively. The results indicate that the 40.5kV self-energy SF6 circuit breaker can meet the requirements of power system to switch capacitor group. The polarity effect is existed in slightly uneven electric field inside of arc chamber. The short arcing time is longer when static arc contact is cathode during current-zero zone.

Arc faults are a fire-safety risk in both AC (alternating current) and DC wiring, but reliable detection of arc faults and determining the appropriate response is particularly difficult in DC plug-load circuits. This paper presents the development of AFCI lab setup to characterize DC arc current in DC circuits operating at 24-80 volts. The process to characterize the arc current utilizes the frequency spectrum of the arc current along with signal processing and a unique algorithm that allow us to develop an effective method to determine DC arcing occurrence. Once identified, an arc fault current interrupter circuit may then be designed to adequately eliminate the arc. Laboratory test setup and equipment for identifying DC arc will be described in this paper. Different scenarios for DC arcing occurrences in the development of the lab test setup will be explained. Several test results using the developed test setup to show the characteristic of arc current will also be presented.

Preinsertion resistors (PIR) are used in combination with circuit breakers to absorb switching transients and come into effect during the “closing” operation of the breaker. It is mainly used for rated voltages equal to or higher than 420 kV for line lengths above 200 km. Although it is an important component, power testing of complete PIR is very complicated and not well defined. Therefore, an attempt has been made in this paper to provide alternative test methods for power testing of PIR without compromising its important parameters. Due to high energy requirements and limitations of the test laboratory, a multipart testing of PIR is necessary to prove its thermal capability and dielectric behavior. Before proceeding with the complete PIR test, the critical parameters of PIR, such as mechanical insertion time, rate of decay of dielectric strength of the interrupter, and PIR switch, etc., should be verified with testing. These test procedures are also explained in detail along with a method to theoretically evaluate electrical insertion time for different network conditions. The series PIR configuration for the metal-enclosed ${\mathrm{SF}}_{6}$ system has been considered in this paper.

The controlled switch became a technical solution for reducing the switching stress. The controlled switching can be applied to any type of commutations. There are now dedicated controllers which are used more often for the switching of the transport and distribution lines, of the small inductive loads, of the capacitors batteries, or for energizing the no load power transformers. The paper deals with the simulation of the commutation of a transportation line by using the distributed parameters model. The controlled switch for fault interruption in transport and distribution lines is compared with the uncontrolled one, highlighting the major differences in what concerns the stress. The primary objective of controlled short-circuit interruption is to restrict the arcing time of the circuit-breaker and thereby seek to reduce the electrical stress and wear on the interrupter.

The transient pressure process in an interrupter, which determines the gas blasting characteristic of an SF6 circuit breaker (CB), is of interest to designers and developers. In this investigation, piezoresistive pressure transducers and thermally and electrically insulating tubes, which damped the reflection of the pressure waves, were employed to measure the transient gas pressure in a 252-kV puffer-type SF6 CB during no-load operation and fault current interrupting. The pressures of the puffer cylinder, throat, upstream, and downstream of the nozzle have been measured. The insulating tube can protect the pressure transducer from the high voltage and high temperature present during fault current interrupting. It is found that the reflection of the pressure wave inside the insulating tube will cause serious high-frequency oscillations, which superimpose upon the actual pressure waveforms during fault current interrupting. Filling the insulating tube completely with small polytetrafluorethylene (PTFE) particles can effectively damp the reflections and greatly suppress the oscillations. The pressure characteristics of the interrupter under 20-50 kA rms current have been analyzed through the method established in this investigation.

In this study, a new concept is proposed on a combination device with functions of a commercial transformer and a superconducting fault current limiter (SFCL). This device serves as a transformer by stepping the voltage up or down in normal condition. When a transient phenomenon occurs in the power system, it serves as an SFCL to limit the fault current. The device quickly detects the line current using a current transformer (CT), and is based on the high-speed, silicon-controlled rectifier (SCR) interrupter operation. This is done by identifying the fault using an SCR switching control system. The test results showed that the fault current was limited by the impedance of the superconducting element a half cycle after a fault occurred. An SCR that initially had a normally open contact was turned on within a half cycle. However, an SCR with a normally close contact was turned off after a half cycle because the current dropped below the holding current after a half cycle. The voltage of the superconducting element was low in the step-down turn ratio condition of the transformer. This was because the secondary and tertiary windings were connected in series due to the SCR-1 turn-off condition, and the sum of voltages on each winding appeared on the superconducting element. By combining the existing power device technology and an SFCL technology, it is expected that the existing problems of an SFCL can be addressed to construct a smart power system.

CO 2 gas is a possible substitute for SF 6 gas in circuit breaker with relatively superior arc interruption performance. To enhance the interruption capacity of the circuit breaker which employs CO 2 gas as its arc interruption dielectric, the interruption principle of the hybrid circuit breaker composed of vacuum interrupter and CO 2 gas interrupter is studied. Based on the black-box arc models of hybrid circuit breaker built in ATP-EMTP, the interactions characteristics of vacuum interrupter and CO 2 gas interrupter and the transient recovery voltage distribution between two interrupters during the interruption process are analyzed. The influence of voltage-dividing capacitors on transient recovery voltage distribution is discussed. The interruption capacity of hybrid circuit breaker and CO 2 gas circuit breaker are compared. The results of simulation demonstrate that preferable transient recovery voltage distribution can be obtained under suitable control strategy while interrupters paralleled with voltage-dividing capacitors. The vacuum interrupter series connected with CO 2 gas interrupter can assist in enhancing the high current interruption capacity of gas interrupter.

The vacuum pressure in Vacuum Interrupters (VI) is usually measured by inducing a magnetron discharge inside them. We have previously reported evidence that if this discharge is continued for long enough it causes the gases to be chemically bonded to solid surfaces in the interrupter, resulting in a permanent reduction of pressure. In a small proportion of interrupters however the pressure returns to a stable level similar to the pre-discharge pressure over a period of hours or days. We now report on measurements of this pressure recovery. It was found that with these VI the cycle of pumping and pressure return is repeatable. With this information it may be possible to adapt magnetron testing procedures to distinguish between pressure rise due to return of permanent gas, which will level off, and continuous pressure rise due to internal outgassing.

A renewed interest for dc breakers has evolved owing to the visions of connecting several HVDC links into a HVDC grid. Several breaker concepts have been presented and some also have been implemented and tested. A new approach is proposed in this paper. The fundamental principle is to take advantage of the fast recovery of the voltage withstand capability in a Vacuum Interrupter (VI) when the current is temporarily forced to zero using a low-voltage power electronic converter. The latter excites an oscillating current in a passive resonant circuit during the time interval needed to mechanically separate the contacts in the interrupter. The sum of the line current (to be interrupted) and the oscillating current passes through the vacuum interrupter and experiences zero-crossings when the amplitude of the oscillating current exceeds the line current. The most important benefit of the proposed concept is that a favorable cost can be achieved, because excitation of the oscillating current only requires a low output voltage (compared to the breaking voltage across the VI terminals) from the converter. The total voltage rating of the semiconductors in the latter therefore is only a fraction of that needed in a hybrid HVDC breaker and, additionally, they are not requested to turn off the main current but rather to commutate close to current zero-crossings. Experimental verification of the concept has been performed with current up to 1.6 kA against 1.2 kV.

The current interruption capacity of gas gap can be enhanced by series connecting with vacuum gap in hybrid circuit breaker. For the purpose of compensating the inferior interruption performance of CO 2 gas gap, as the substitute for SF 6 gas gap, the interruption principle and the dielectric strength recovery process of the series gaps of vacuum gap and CO 2 gas gap are studied in this paper. Based on the established test prototype, tests are carried on series gaps to investigate the influences of various arcing times, voltage-dividing capacitor, and CO 2 gas pressure on its interruption performance via synthetic test circuit system. The test results convey that, CO 2 gas gap with gas pressure at 0.8 Mpa can recover its dielectric strength faster and withstand higher recovery voltage under the effect of voltage-dividing capacitor while vacuum gap undertakes initial transient recovery voltage. But limited by the simple structure of gas interrupter and the interruption performance of CO 2 gas, CO 2 gas can't recover its dielectric strength rapidly.

The Redlich-Kwong state equation of the real gas and the governing equations of the flow field were combined to solve the problem. The distribution of physical parameters of the interrupter was attained under the condition of the circuit breaker in small capacitive current interruption by analysis of the 126kV capacitor group SF 6 gas circuit breaker arc extinguishing chamber in air flow field, which is according to enthalpy flow arc model and dynamic model of non-equilibrium arc energy built by microscopic parameters of plasma. The dielectric recovery characteristic curves in arc contacts after the arc extinguished were attained through the coupling calculation in the field of electric and gas flow. Calculation results show that: When the circuit breaker is opening the small capacitive current, the effect of breaking speed on arc burning time is very small and arc extinguished in advance. The arc gap conductivity is about 700S/m, and the thermal conductivity is about 1.1W/m-K at arc extinguishing time. The transient recovery voltage is always lower than that of the breakdown voltage, and the electric arc can successfully break without reburning. To make the short arcing time have a large arc distance, and the large nozzle should be open enough to be strong for the gas blowing condition, the optimum opening speed is 9.6m/s.

Arc faults are a fire-safety risk in both AC (alternating current) and DC wiring, but reliable detection of arc faults and determining the appropriate response is particularly difficult in DC plug-load circuits. This paper presents the development of AFCI testing for DC circuits operating at 24–80 volts. Protecting these circuits from arcing is more difficult than the more prevalent Photovoltaic circuits because of the diversity of loads that may be present. The AFCI testing described in this paper will allow us to identify an effective method to determine DC arcing occurrence. Once identified, an interrupter may then be designed to adequately eliminate the arc. Laboratory test setup and equipment for identifying DC arc will be detailed in this paper. Different scenarios for DC arcing occurrences in the development of the lab test setup will be explained. Several test results of the developed testing tool will also be presented.

When medium-voltage reduced-voltage autotransformer (RVAT) motor starters fail, also referred to as Korndorfer starters, particularly ones in which there is no clear failure to the core or tap-to-tap but just layer-to-layer deep down in the windings, the results are almost always catastrophic. An offshore platform is used as an example to discuss site-specific solutions that are based on the recently developed switching transient analysis, sweep frequency-response analysis, and state-of-the-art electromagnetic transient program (EMTP) simulation techniques. This paper will explain how the power system, interrupter, and transformer interact and outline the steps to solve this long-standing problem as well as present the newly applied solutions. Since the implementation of these new solutions, no further failures have occurred.

In the minds of people health has been a very important parameter, so a monitoring system is required to keep them alert about their health. Monitoring systems are also required in Intensive Care Unit of various hospitals. Hospital staff faces difficulty in handling devices due to their bulkiness and huge number of wires while giving medication to the patient. Monitoring system requirement is of very small size and low power operation. A small size, wearable device is presented in this paper, which consists of PSoC 4, photo interrupter and a very small size Bluetooth module. The system is totally wireless due to the use of Bluetooth module. Different sensors used are attached on the wrist for experimentation. Photo interrupter is used to read the data in the form of analog signal which is further amplified and converted to digital signal by ADC present in PSoC controller. PSoC is used mainly to reduce the system size, as both analog and digital peripherals are available inside a single chip. Due to this the discrete analog components such as OpAmp, ADC and Filter are reduced. Analog signal obtained from sensor is processed by the controller and the values of Heart Rate (Pulse wave) and Temperature are calculated. Temperature is obtained using the LM35 sensor. Total system is mounted on a PCB and sensors are taken out with the help of wires. The PCB design is embedded in a black box. System operates on 3.3V and current requirement is less that 50mA, as the deep sleep mode has been used in both PSoC and Bluetooth. The system is powered by a Lithium Ion battery. A wireless wearable system is built which gives two different parameters of health i.e. heart rate and body temperature. The problem faced by doctors and nurses can be reduced by using this small size and wireless device.

The usefulness of popular occlusional heads to extended, time-frequency analysis of post-interrupter respiratory data was tested in this study. A portable mobile interrupter module, designed to acquire (also in telemedical system) raw signals of mouth pressure (Qao) and airflow (Pao), enabled flexible valve operation during normal breathing and flow induced by the airflow generator. The potential for algorithmic development of data processing procedures and hardware limitations of the shutter-type valve by Jaeger and Micro Medical is depicted here. The power spectrum density of Pao and input interrupter impedance (Zint), calculated by the Micro Medical interrupter, were sensitive indices of respiratory mechanics measurement, but problematic natural oscillations and leakage during valve closing reduced the clinical relevance of the assessments. These hardware specifications represent prerequisites for prospective research in a sensing technology domain on an optimal valve-transducer unit design.

High-power lasers (>+21dBm), because of their ability to transmit long distance signals, have gradually become the common solution for signal transmission systems including regional cable television, Fiber To The Home (FTTH), and gigabit passive optical networks (GPON). However, if protective design is not implemented at the client-side facility, users may be exposed to health hazards caused by the high-power laser, e.g. direct eye exposure to laser beams. High-power optical adapters with photo-interrupters use metal shutter to prevent direct laser beam exposure to the eyes. They have progressively replaced conventional optical adapters and have entered the market mainstream. Our study uses the elastic-plastic theory together with parametric design to investigate the effect of geometry on the initial photo-interrupter spring-back angle. Once the metal spring-back stabilizes after several attempts of insertion and extraction, the initial springing-back angles are found to be the same as the simulated results. In our study, it is observed that factors including the ratio of the notch width to the total width of the metal shutter plate and the relationship with the boundary conditions have significant influence on the springing-back angle. These can be used as references in design control.

The feasibility of using a magnetodynamic current interrupter for switching multimegaampere current pulses is considered. The operation of the interrupter is based on the fast buildup of edge instabilities. A technical solution is suggested, and the performance of the interrupter when used in the second stage of peaking the current of helical explosive magnetic generators (HEMGs) and capacitor banks is predicted. It is shown by computer simulation that the interrupter can operate in the submicrosecond range and switch currents as high as several tens of megaamperes, the operating speed of the interrupter increasing with linear current density. The limit actuation time of the interrupter may be on the order of 100 ns. A prototype of the interrupter is experimentally verified on a capacitor setup by switching currents with an amplitude of 4.3–4.5 MA.

We describe an off-line nanosecond charging device for a short forming line; the device has been created on the basis of an inductive energy storage unit. Energy storage is carried out by the current of an explosive magnetic cumulation generator, and the energy output to the load, by means of an electroexplosive current interrupter. The use of a two-stage, instead of a one-stage, magnetic cumulation generator, consisting of a preamplifier and a dynamic transformer, and two smaller-size generators with sequential connection of secondary windings of dynamic transformers, one of which is connected to the inductive storage unit, and the other, to the current interrupter—has made it possible to substantially increase the line charge voltage. As a result, within a time on the order of 100 ns, it was possible to charge a forming line with an electric length of 5 ns to a voltage of ≥1 MV.

The breaking ability of a vacuum arc interrupter with a uniform transverse magnetic field formed by a system of permanent magnets was investigated experimentally. The vacuum interrupter with a 0.5-μF shunting capacitor switched off a dc current of up to 150 A at magnetic fields of 100–180 mT. At magnetic fields of 120–160 mT, the breaking ability of the vacuum interrupter was increased to 300 A by introducing a nonuniformity in the magnetic field distribution near the contact surface.

In recent years, a number of disruptive dielectric failures of unknown cause have occurred on grading capacitors installed on circuit-breakers switching shunt reactors. In an attempt to clarify the origin of these failures, the electrical stresses to which the grading capacitors are subjected in service have been studied. Following initial studies, attention was focused on the first parallel circuit, i.e., the circuit consisting of the grading capacitor and the associated interrupter. It is proposed that the observed failures can be explained by unequal voltage sharing under switching operations, where one interrupter of a pole prestrikes or reignites momentarily before the other interrupter(s) of the same pole. Simulations show that under worst-case conditions, the voltage across one grading capacitor of a pair may then approach a value of 1.5 times the source voltage in the case of a prestrike and three times the source voltage in the case of a reignition. These are substantial dielectric stresses as they correspond to three and six times the stationary voltage across the capacitor. Measurements of voltages and currents inside the first parallel circuit would be very helpful in a further investigation of these phenomena. Copyright © 2010 John Wiley & Sons, Ltd.

An asymmetrical structure GCB that employed the closing resistor method has an interrupter and a closing resistor contact in one shield, and so the shield diameter becomes large. In this study, we investigated the optimum tank diameter and major radius of shield electrode of asymmetrical structure GCB by three-dimensional electric field calculation. We also investigated these optimum structures of symmetrical structure GCB and compared the result with that of the asymmetrical structure GCB. We found that the tank diameter of asymmetrical structure GCB becomes larger than the tank diameter of symmetrical structure GCB by 24%. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(2): 14–20, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20741

This paper is the first in a series devoted to the metrological evaluation of the interrupter technique (IT). The aim of it is to propose effective modification of the classical algorithm and to summarize the research concentrated on evaluating the usefulness of the pressure and flow data frequency analysis on the estimation of the mechanical status of lungs. Based on the Frey et al. reports, a physical–mathematical representation of the respiratory system (modified DuBois’ model) was used. The electrical analog expresses the division of the physiological object into the tissue and airways segments. For such a theoretical structure, the optimal configuration of the measurement signals and the tools of their analysis have been simulated by means of forward–inverse modelling. At this stage, the possibility of expanding the inference on the system mechanics was shown. At the same time, the improvement of repeatability and evaluation precision in relation to the known IT realisation was observed.

During the closing operation of a capacitive load by a vacuum interrupter, there is always a prestrike arc. An inrush current with high frequency and high amplitude flows through the prestrike arc. This prestrike arc with a high energy density destroys contact surfaces locally, resulting in welding between the mated contacts. Consequently, the opened destroyed surfaces, which enhance the local electric fields and bring metal particles into the contact gap, increase the restrike probability of the interrupter under a DC recovery voltage. The objective of this paper is to establish a kinetic model to investigate the characteristics of prestrike arcs and the energy fluxes to the electrodes during closing capacitive loads. The Particle in Cell-Monte Carlo Collision(PIC-MCC) method was adopted in this model to describe this high density plasma within a small gap. The distance between the contacts was set to 1μm. Three different electrode temperatures were set to investigate their influence on results. Electron-atom elastic collision and electron impact ionization were considered in the model. According to the results, the plasma density, current density and energy fluxes to electrodes increased with electrode temperature. The length of arc column also increased with electrode temperature. Electron current was main component of the current. Electron energy flux was less than ion energy flux at cathode, while it was just the reverse at anode.

Side channel blowers are used in a wide range of applications like the paper and printing industry, dental vacuum, industrial vacuum cleaners or road sweepers. As all these applications occur in the neighborhood of human beings, a low noise emission of the side channel blowers is necessary. To obtain an closer insight to the flow field and the noise produced, this paper is dealing with pressure measurements in the rotating impeller of a double flow side channel blower. Seven thin line pressure sensors are integrated into two opposing blade surfaces to measure the pressure distribution within one blade segment. The necessary modifications to the impeller as well as the housing and the mounting of the telemetric system are demonstrated. A pressure correction will be applied to correct the pressure offset due to the used measurement technique. The results show the exemplary time trend of the pressure, the phase averaged pressure generation for different working points and rotational speeds of 50Hz and 60Hz. Especially, the pressure distribution during the passage of the interrupter region is analyzed. Additionally, the results are presented in the frequency domain. The pressure measurements are linked to the acoustic noise emission by the application of an acoustic analogy and its source definition by the second time derivative of the measured, hydrodynamic pressure.