A type of circular Pearcey-like vortex beam (CPLVB) is introduced numerically and experimentally, combining the properties self-acceleration abruptly autofocusing in off-axis position. The interplay between spiral phase modulated arbitrary predesigned trajectories assists to present a special shape which suitable for manipulating guiding particles along trajectories. propagating hyperbolic, hyperbolic secant generates twisting hollow guide channel, parabolic bottlelike structure constructed...

The risk warning for steady-state power quality in the grid is essential its prevention and management. However, current methods fall short predicting trend while accounting potential risks. Consequently, this study introduces a novel method utilizing VMD-LSTM fuzzy model. Firstly, index prediction based on variational mode decomposition (VMD) long short-term memory (LSTM) proposed. This approach significantly enhances accuracy. Secondly, incorporating kernel density estimation (KDE) model...

The current-limiting performance of the smoothing reactor is weak. traditional saturated core-type fault current limiter (TFCL) better, but will cause dc circuit breaker (DCCB) to endure high overvoltage, energy absorption and also increase fall time. When DCCB recloses on permanent fault, whole system face a harmful second shock that cannot be solved effectively by TFCL. To solve above problems, secondary active limiting (SAFCL) topology proposed. It can reduce overvoltage greatly....

With the increase of proportion distributed generators (DGs) access in distribution network, it transforms from a traditional radial network to multi-terminal active which brings many challenges relay protection. If part is disconnected all upstream networks, can create unplanned islands that compromise personal safety, power quality, and out-of-phase reclosing. As result, essential equip DGs with anti-islanding Currently, protection based on impedance measurement great interest because has...

In order to promote the consumption of distributed generations and meet power flow regulation requirements distribution network, a novel multiline fast electromagnetic unified controller for network (D-MFEUPFC) is proposed. It has advantages compact structure, response, good economy, high reliability with traditional mode. Besides, based on multiwinding transformer hybrid on-load tap changer, D-MFEUPFC can quickly adjust absorb output new energy. The operating principles characteristics are...

The inductance of a permanent magnet-biased saturated fault current limiter (PMFCL) increases automatically with the current. It can quickly restrain rising speed direct (dc) However, when dc circuit breaker (DCCB) opens, PMFCL will delay drop and generate overvoltage, which increase voltage stress on DCCB. In this article, new type fast-response FCL (NFCL) is proposed. has advantage improving speed. Besides, it reduce DCCB thus protecting expensive insulated gate bipolar transistors in...

The traditional saturated core type fault current limiters (TFCLs) cause large energy absorption and high overvoltage in direct circuit breakers (DCCBs). Energy absorbing FCLs (AFCLs) coils to bear the for a long period is slow. In order solve problems of TFCLs AFCLs, novel fast storage dc FCL (EFCL) topology proposed this article. EFCL not only reduces DCCBs but also quickly stores energy. First, working principle are proposed. design requirements main electrical size parameters then...

When the fault current in high voltage direct (HVDC) systems rises to a higher level, DC circuit breakers will have either insufficient capacity or require larger sizes with increased costs. Fault limiters (FCLs) can reduce turn-off stress and stringent requirements on breakers, thereby also lowering their cost. The use of saturated core FCLs, which fast response times low power loss, is promising approach for this issue. However, parameter design principles kind FCL has so far not been...

Grid-tied distributed generators (DGs) need to be equipped with anti-islanding protection avoid the impact of unplanned islanding, which would affect system stability, auto-reclosing, and personal safety. Among active protections, impedance measurements based on signal injection have advantages a low non-detection zone (NDZ) are less prone maloperation during grid disturbances; however, there problems interference in multi-DG systems. Hence, angle measurement method signals injected...

Saturated core fault current limiters are effective means to limit short-circuit currents in high voltage power systems. To solve its problems of a low rate utilization and large loss, this study proposes multifunctional saturated-core limiter (MFFCL) with hybrid excitation system. The MFFCL can the control flow reduce losses. composition topological structure provided, an equivalent electromagnetic circuit model is then established, working mechanisms limiting regulating analyzed. Following...

We introduce the propagation of Pearcey Gaussian (PG) beams in a strongly nonlocal nonlinear medium (SNNM) analytically. Our results show that PG propagating SNNM have two different focusing positions. The intensity peak appears at positions depending on selection parameters. In addition, effects parameters and scaling factor trajectory, position focusing, evolution between focus locations, radiation force are studied.

With the increasing penetration of distributed generation (DG) in distribution networks, its impact on stability grid has become more pronounced. To improve low voltage ride-through (LVRT) capability DG, a LVRT control strategy for improving reactive power support DG is proposed. This designs two output current equations as based requirements different positive sequence voltages at point common coupling (PCC) DG. By comparing positive-sequence PCC with boundary corresponding equation...

In this paper we utilize the half Pearcey function as a means to describe surface plasmon, plasmon. The abrupt autofocusing and self-healing properties from superposition of plasmon are observed discussed. tunable focal intensity covers three orders magnitude property can be maintained with potential well. Additionally, $\ensuremath{\pi}$ phase offset, construct multiple plasmonic bottles chirp factor; both bottle structure propagating direction adjustable. focusing under depend on spatial...

In response to the poor reliability in identifying fault direction distribution networks with Inverter Interfaced Distributed Generators (IIDGs), considering control strategy of low-voltage ride-through, a criterion based on post-fault positive-sequence steady-state components is proposed. Firstly, output characteristics IIDGs ride-through capability are analyzed during grid failure, and applicability existing directional elements network connected dispersively demonstrated. Subsequently,...

In active distribution networks (DNs), distributed energy resources (DERs) must be disconnected from the grid prior to automatic reclosing actions. Many scholars have proposed non-voltage checking methods, but a significant challenge arises; many substations lack line-side voltage transformers (LSVTs), making these schemes impractical. To address this, we introduce time-limited adaptive (TLAR) method that integrates DERs’ anti-islanding protection (AIP) with reclosing. This estimates AIP...

The typical single-event characteristics of a voltage dip include residual voltage, duration, type, point-on-wave and phase-angle jump, which may influence the operation sensitive equipment under dip. This is foundation on can be accurately calculated to mitigate challenge existing studies that no unified systematic method calculate multiple characteristics. study proposes robust adaptive based Goodness-of-Fit (GoF) test First, calculation for transition segment proposed GoF test. Then, four...

Abstract This paper proposes a novel approach to visualize the fractional orbital angular amentum (OAM) flow of light fields at example Lommel tornado wave (LoTW) along propagation direction in free space. The that is based on transverse intensity distributions LoTWs can be used identify and quantify OAM. energy continuously distributed flexibly controlled via asymmetry factor topological charge. Furthermore, OAM density concentric rings chiral paths employed demonstrate convincingly as...

In order to establish a photovoltaic(PV) grid-connected system model that is suitable for studying faults in medium-voltage distribution networks, it advisable conduct linearized and simplified equivalent research on each component of the PV according specific fault scenarios. The primary focus should be linearizing simplifying modeling array, which serves as energy supply link. impact medium voltage network array output analyzed, maximum power point(MPP), short circuit current point, open...

Line break faults commonly occur in distribution networks and pose the risk of electric shocks to nearby individuals animals. This study aims address challenge identifying direction a line fault. Specifically, we develop model for single-phase fault small current grounding system focus on analyzing steady-state voltage changes both sides point. The characteristics ungrounded resonant are compared summarized. Based these characteristics, more reliable method is proposed identify by utilizing...

In response to the growing demand for economic and social development, there has been a significant increase in integration of distributed generation (DG) into distribution networks. This paper proposes dynamic risk assessment method voltage violations networks with DG. Firstly, considering characteristics random variables such as load DG, probability density function estimation based on boundary kernel is proposed. accurately models under different time external environmental conditions,...

The synthetic electric field of an ultrahigh voltage direct current (UHVDC) transmission tower in a high-altitude area is complex, which makes it difficult to protect the operators. Therefore, necessary study field. Firstly, this establishes mathematical model ion flow and determines solution process. Secondly, relationship between synthesis line mobility, wind speed, number wire splits analyzed using finite element simulations. Five typical operation positions are then selected for...