DC circuit breaker (DCCB) is the best choice for grid fault clearing and isolation. The naturally commutated hybrid (NHCB) has characteristics of low cost, loss, fast breaking speed, which wide promotion significance. However, currently time NHCB at ms-level. Therefore, this paper focuses on research mechanical switches. Firstly, we analyse working principle switch, study electromagnetic repulsion mechanism, influence electrical parameters motion by simulation. Then optimize switching...

Abstract In recent years, domestic DC transmission projects have been rising. High-voltage circuit breakers, as key equipment in power grids, also received more and attention from various scientific research units. However, the current on breakers is still topological stage. There a lack of experience development specific products. As complex set integrated equipment, high-voltage many components very potential distribution. To ensure safe reliable insulation structure not only sufficient...

Abstract This paper presents a notched ultra-wideband antenna designed to suppress interference from narrowband communication systems. The features defected ground structure and stepped microstrip feedline for improved impedance matching enhanced bandwidth. A bent slot is incorporated into the radiating patch achieve band-notched characteristic. It has wide tunable frequency range which allows flexible adjustment of notch frequency. Traditional optimization methods, such as numerical...

Hybrid DC circuit breakers (HDCCBs) have excellent performance in terms of breaking speed and low losses become the mainstream technology for dc fault isolation grids. However, because limitation solid-state branch HdcCBs, existing HdcCBs are still weak high current. Although ability can be improved by series parallel devices, cost will increase rapidly, it is very difficult to share current paralleling a single type device. This article proposes novel HdcCB topology that combines two types...

This research proposes a solid-state dc circuit breaker for low voltage system based on reverse-blocking integrated gate-commutated thyristor (IGCT). The topology gets easier as result of IGCTs' ability to withstand reverse voltage. To further enhance the breaking process, we develop snubber branch with metal oxide varistors (MOVs) and capacitance. advantages disadvantages three distinct branches—the no-snubber, resistance–capacitance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Hybrid DC circuit breakers (HDCCBs) are promising solutions to breaking issues. However, HDCCBs based on forced commutation have the disadvantages of high conduction loss and cost. Natural low cost but face contradictions arc voltage fast post-arc recovery. This paper proposes a natural commutation-type hybrid breaker series vacuum gas gap. The characteristic gap is used drive commutation, dielectric recovery withstand transient overvoltage. It has advantages compact volume. characteristics...

A flexible dc grid is important for supporting large-scale new energy integrations. To ensure the stable operation of grid, a circuit breaker (DCCB) needed fault isolation. At present, cost DCCBs high, and breaking capacity limited. This limitation can be effectively solved through coordination current limiters (FCLs) DCCBs. In this article, coordinated interruption topology an magnetic coupling FCL (MCFCL) hybrid DCCB proposed. strategy based on current-limiting dissipation proposed to...

Flexible dc grids have become an important means to support large-scale new energy integration utilization due their advantages of flexible power control and high efficiency. generally consist multiple converter stations lines. Therefore, there are line intersection points, circuit breakers (DCCBs) need be installed at the isolate faults. Multiport hybrid DCCBs (MPHCBs) based on topology optimization can greatly reduce cost by replacing two-port with one multiport DCCB intersection. However,...

An effective method to directly produce high-quality graphene nanowalls (GNWs) on quartz substrates was demonstrated using an advanced self-assembled ratio-frequency plasma-enhanced horizontal tube furnace deposition system under different growth times from 60[Formula: see text]s 150[Formula: at a substrate temperature of 850[Formula: text]C without any catalyst. The synthesized well-connected three-dimensional GNWs feature outstanding electrical and optical performance: the sheet resistance...

Medium voltage dc power system has the characteristics of low line impedance, resulting in high peak and fast rise rate fault current. For example, current an onboard 10 kV grid can to more than 40 kA 3 ms after failure. Therefore, it is necessary configure circuit breaker with breaking capacity. In this letter, a novel high-power hybrid based on integrated commutation compound electronic switch proposed. By giving full play complementary advantages insulated gate bipolar transistor (IGBT)...

Abstract The occurrence of breaking overvoltage in a DC circuit breaker (DCCB) poses potential threat to the safe operation grid. Based on structure ±10 kV three‐terminal distribution network, this paper sets up medium‐voltage DCCB and formulates fault protection strategy. Additionally, simulation model system is developed analyse characteristics within network across different nodes conditions. By examining factors that influence overvoltage, unravels fundamental mechanisms associated with...

Medium voltage dc system has fast rise rate in the event of a short-circuit fault. To avoid high-peak fault current, it is necessary to configure circuit breaker with operation. Solid-state short breaking time and high reliability, which suitable for Dc system. In this letter, novel oscillating-commutation solid-state based on compound integrated gate-commutated thyristors (IGCTs) proposed. By combining IGCTs different advantages, such as current withstand-voltage capability, proposed...

Abstract A novel tri‐band antenna end‐loaded with Koch fractal loops and was designed for radio frequency identification (RFID) applications, based on FR4 substrate. Before after introducing a mirror array meander‐line structure, the proposed simulated investigated. The results show that great improvements have been reached, including return loss decreased to about 56 dB bandwidth increased 420 MHz at 2490 MHz, miniaturized size. With prototype fabrication, we also verified good performance...

Solid-state DC circuit breakers are key equipment for the protection of medium and low voltage systems most effective means isolating short-circuit faults. With development high-power power electronics, performance solid-state has also improved. In this paper, a new topology anti-parallel connection is proposed based on reverse blocking IGCT, which requires fewer switches, lower cost smaller loss than anti-series diode-bridge structure. Besides, snubber branch design method MOV-C proposed,...

Generator circuit breaker (GCB) can realize reliable isolation between generator and system under different conditions to avoid damage of equipment. With the increase alternator capacity, GCB with higher rated current short-circuit breaking capacity is required. In scenarios large currents, vacuum switches are difficult apply due insufficient heat dissipation while gas prone re-breakdown high transient recover voltage (TRV). Moreover, severe ablation when will result in a short electrical...

Cities are critical battlefronts in the struggle to mitigate climate change crisis. Urban planning is widely recognized as an important policy and technology tool for low-carbon development of cities. However, methods integrating concept into existing system practices have yet be studied. More cases still needed examine wisdom. By taking Chinese city Xiamen a case study, this study attempts show city's efforts make itself "a China" field urban planning,to sketch out general governance...

A hermetic package by silicon-Pyrex7740 anodic bonded structure which has Al electronic contact pads in the bonding area been successfully demonstrated. Silicon wafer was doped with boron at dose about 2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sup> cm xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> , then were deposited using RF sputtering on silicon and Pyrex7740 respectively. Sufficient mechanical strength test after...

In this paper, a Z-axis micromachined gyroscope with new decoupled design was presented. The consists of dual proof mass, sense frame and drive structure. is constrained in the direction anchored on substrate, which minimize influence from motion mass direction. also restricted to oscillate ANSYS has been used make modal analysis harmonic determine vibration characteristics gyroscope. We introduce decoupling ratio (ηDtS) mode (ηStD) design. results show that are well decoupled.

The nanocrystal 3C-SiC/ZrO₂ bilayer films that could be used as the protective coatings of zirconium alloy fuel cladding were prepared on a single-crystal Si substrate. corresponding 3C-SiC film and ZrO₂ also dividedly synthesized. microstructure was analyzed by grazing incidence X-ray diffraction (GIXRD) cross-sectional transmission electron microscopy (TEM). with less than 30 nm crystal size synthesized Plasma Enhanced Chemical Vapor Deposition (PECVD) annealing. formation mechanism some...

As a high-power electronic device, IGCT has the characteristics of strong turn off, high surge capability, and withstand voltage ability, which makes it receive more attention be used widely, such as circuit breakers inverters. However, since Intergrated Gate Commutated Thyristors (IGCTs) is whole-wafer current distribution junction temperature inside chip cannot measured, making impossible to obtain status increasing risk device failure. In this case, margin can only increased avoid failure...