Power system security is one of the most considerable studies to understand the vulnerability of various contingencies occurring on the system. In this paper, the contingency ranking is performed for single-line outages. Among the increments of the load variation for cases like only active power loading, only reactive power loading, and both the active and reactive power loadings are considered to create various scenarios using the Active Power Performance Index (APPI). These scenarios have been classified through a Support Vector Machine Classifier (SVMC) to observe the impacts of line outage. The data has been generated using MATLAB software for the UPSEB Indian Utility 75-bus system. Python programming is used to classify using SVMC.

Distributed generations are practically operated at the rated maximum power output. The locking off and on into the grid network of the intermittent power generating units is on availability basis. There are significant integration challenges posed by wind power generation due to its intermittency nature which seriously affect power grid stability and reliability issues related to grid power quality and voltage profile. Several reliability indices can be established to assess the distribution network reliability; they include ASAI, SAIFI, AENS and EENS. This study had the main purpose of optimizing placement and sizing of wind distributed generations through the application of the Particle Swarm Optimization algorithm to attain voltage profile improvement as well as network reliability enhancement by power loss reduction for radial distribution network - IEEE 33-bus system. The proposed PSO-based algorithm adequacy was investigated using MATLAB simulation on a radial distribution network - IEEE standard 33-bus test system, with a case study of Genetic Algorithm being used for validation of the solution techniques and model developed. The RDN test system is connected to a total of 3.32 MW and 2.71 MVAr; both real and reactive loads respectively. Modelling of the wind power generation considered for grid integration was variable reactive power model. A cut-off wind speed of ≥ 6 m/s on average was considered for power generation. Results from the analysis yield 0.2115 p.u of average active power produced by the wind turbine generator. 206.87 kW and 139.13 kVAr were the APL and RPL initial network configurations obtained respectively at 0.83pf when no DG was integrated. When wind DG is integrated at optimal placement and capacity, the reduction of the overall network power loss is 68.12% and 61.43% for real and reactive power loss accordingly. The voltage profile improved by 8.17% on installation of wind DG. The network ASAI reliability index value before wind DG integration was 0.99743 p.u. which improved by 1.81% after their installation. In general, network power losses are minimized besides acceptable voltage profile being maintained for a sustained distribution system reliability when several wind DGs are integrated.

Abstract Background The human immunodeficiency virus (HIV) consists of three main genes (gag, pol, and env) encoding structural proteins and enzymes. HIV diagnostic tests use various methods, combining screening and confirmatory assays to differentiate antigen and antibody positivity, essential for clinical interpretation of the infection stage. Screening can be done using chemiluminescent (CL) assays and other widely recognized methods capable of detecting antigens and antibodies. Among the most well-known confirmatory tests are Western blot (WB) and Rapid Immunoblot, also called dual-path migration immunochromatography (DPP – Dual-path Platform). This study aimed to compare the Western blot and dual-path migration immunochromatography techniques for confirming HIV diagnosis. Methods Both methods (WB and DPP) were compared using 71 serum samples with known results from 4th generation CL (Abbott) and WB (BioRad) methods. Based on the CL and WB data, the selected samples were grouped as follows: group I (non-reactive CL and non-reactive WB), group II (reactive CL and non-reactive WB), group III (reactive CL and reactive WB), and group IV (reactive and non-reactive CL, and indeterminate WB). All samples were processed by the DPP method using the Geenius™ platform (BioRad) according to the manufacturer’s recommendations. Focusing exclusively on the identification of HIV-1 infection, the CL method detects the p24 target or antibodies anti-HIV-1, while the WB method could detect the gag targets: p17, p24, p55, pol: p31, p51, p66, and env: gp41, gp120, and gp160. The DPP method is designed to identify the targets p24, p31, gp160, and gp41. Divergent results were confirmed using the RT-qPCR molecular method. The clinical outcome for data was analyzed according to the guidelines of the Technical Manual for HIV Infection Diagnosis in Adults and Children from the Brazilian Ministry of Health. Statistical analysis was performed using general agreement analysis and Cohen’s kappa index in EP Evaluator software version 14.2. Results The analysis was conducted considering the clinical outcome (positive, negative, or indeterminate) for both analytical scenarios: CL + WB and CL + DPP. Among the 71 samples evaluated, group I (N=7), group II (N=13), group III (N=49), and group IV (N=2), only two samples from group IV showed divergence between the WB and DPP results. One of them showed reactive CL, indeterminate WB, positive DPP, and detectable viral load by RT-qPCR assay. The second sample showed non-reactive CL, indeterminate WB and negative DPP, presenting undetectable viral load by RT-qPCR. A concordance of 97% and kappa = 93.9% were obtained when the results from both groups: CL + WB and CL + DPP were compared. The only divergences found were in those samples mentioned above. Conclusions Although there was no 100% agreement between the targets, no clinically significant difference was found between the WB and DPP methodologies, both combined with CL. The WB method is considered the gold standard for confirmatory HIV diagnosis, but the DPP method stands out for presenting speed, accessibility, and ease of result documentation due to automated reading. Therefore, the DPP method represents an attractive alternative for laboratories facing high demand and limited resources.

(-)-Epicatechin targets early growth response protein 1, an inflammation-associated ferroptosis regulator, to ameliorate metabolic dysfunction-associated steatotic liver disease.

ABSTRACT A design strategy with multifunctional network for out‐phasing power amplifier (OPA) is proposed. The multifunctional (M‐F) network using coupled lines is implemented to achieve reactive loading compensation of the fundamental wave and harmonic controlling, thereby enhancing efficiency. Leveraging the characteristics of the coupled lines, this configuration achieves conjugate reactance matching for upper and lower branches of the OPA using single network. In addition, the multifunctional network performs as the drain bias circuit, reducing the number of components needed for the output network. Benefiting from the proposed design strategy, efficiency enhancement and simplified circuit structure can be simultaneously obtained. An OPA using GaN devices with harmonic control coupled network is designed and implemented. The designed OPA achieves 44.3‐dBm saturated power at 2.4 GHz. Meanwhile, 72.5% and 58.7% drain efficiencies are obtained respectively at 6‐dB output power back‐off and saturation output power. For the down‐link long‐term evolution (LTE) signal with a channel bandwidth of 20 MHz and a peak‐to‐average power ratio (PAPR) of 8 dB, the average adjacent channel power ratio and error vector magnitude of the fabricated OPA reach −51.2 dBc and 1.48% after digital pre‐distortion.

In power systems, the Unified Power Quality Conditioner (UPQC) is intended to lessen the voltage drop or rise in the voltage of the source. This research proposes a new technique that integrates the optimisation concept and gives a superior UPQC allocation in distribution grids. The key goal is to allocate a UPQC system in distribution grids at a reasonable cost and lower the losses of the distribution network. Varied linear and nonlinear frameworks of reactive loads are considered to accommodate dissimilar utilisation patterns and estimate demand with the least amount of inaccuracy. A new hybrid approach named Squirrel Search Algorithm Inherited Aquila Optimiser (SSA-AQ) that consolidate the concepts of Squirrel Search Algorithm (SSA) and Aquila Optimisation (AO) is used to select the optimal position of UPQC. As a consequence, the results demonstrate that combining DRPs with UPQC allocation successfully resulted in lower costs and losses.

This work presents the use of a novel impedance coupling technique and electrical length increase by using stub loading placed from the radiator to the ground plane. This method is applied to the design of a small four-element ultrawideband (UWB) MIMO antenna arranged in axial symmetry to achieve a compact array size while obtaining a bandwidth starting from a very low cutoff frequency compared to a conventional radiator operating at the same frequency. The four-element MIMO antenna, with an operational bandwidth of 1.9 GHz to 30 GHz, is based on a wideband monopole with a semicircular geometry, fed by a coplanar structure and an L-shaped half-ground plane section. To increase the electrical length of the structure and achieve a compact antenna design, reactive stub loading is introduced, placing it on the backside of the substrate, located orthogonally between the radiator and the L-shaped ground plane, obtaining a small-sized configuration. The axial symmetry is employed to increase the antennas’ isolation by taking advantage of the orthogonal positioning and making the radiated fields have a low correlation. The antenna array footprint measures 48 mm × 48 mm, corresponding to 0.3λ0 × 0.3λ0 at the lower cutoff frequency. The array exhibits a low envelope correlation coefficient (ECC) of around 0.033 at 2 GHz, and less than 0.001 at the rest of the bandwidth; a diversity gain (DG) of approximately 10; a stable total active reflection coefficient (TARC) below −10 dB; interport isolation between 20 and 40 dB; and an average gain of 2.8 dBi.

The growing adoption of renewable and sustainable energy sources such as solar and wind has highlighted the need to seamlessly integrate these into existing power systems to promote sustainable energy solutions. Microgrids play a crucial role in enhancing grid performance by mitigating power quality issues. By operating as active filtering units, they provide reactive power support, harmonic suppression, and load balancing at the Point of Common Coupling (PCC). One major challenge with standalone DC microgrids is maintaining reliability, which can be addressed by interconnecting them with the main utility grid. In this context, an Artificial Intelligence-based Icosϕ Control Algorithm is introduced to optimize power sharing and enhance power quality in smart microgrid environments. This control strategy is designed to intelligently respond to uncertainties such as dynamic load changes, varying battery charge levels in microgrids, and fluctuations in electricity tariffs, which depend on the availability of renewable power. The study delves into the coordinated operation of wind and solar-based microgrids connected to the main grid, emphasizing intelligent power flow control to alleviate grid stress and elevate power quality. A simulated model of a smart grid with multiple renewable-integrated

Immersive applications (VR/AR) on Android platforms impose unprecedented demands on mobile system-on-chips, creating unique resource management challenges that conventional approaches fail to address adequately. This article presents a design-focused proposal for a Dynamic Resource Allocator (DRA), an intelligent system component engineered specifically for immersive Android platforms. While traditional resource management systems prioritize battery efficiency and reactive load response, immersive applications require consistent frame rates and minimal latency to prevent cybersickness and maintain user comfort. The proposed DRA architecture employs proactive monitoring, predictive modeling, and coordinated control across CPU, GPU, display, and thermal subsystems to maintain perceptual stability under variable load conditions. By dynamically allocating resources based on predicted needs and user experience targets rather than conventional computing metrics, the DRA aims to bridge the gap between hardware capabilities and human perceptual requirements. The article examines the limitations of current resource management approaches, details the DRA's architectural components and allocation strategies, addresses implementation challenges, and explores future research directions including on-device machine learning, biometric feedback integration, and hardware-software co-design opportunities for immersive computing platforms.

The mode of operation of a regulated capacitor unit (CU) with a voltage of 0.4 kV is simulated in order to study the economic efficiency of its operation in the electric power supply network of electricity consumers. The daily schedules of active and reactive load of the 10/0.4 kV transformer substation and the supply network were analyzed, the operation modes of the CU were investigated, and the indicators of the economic efficiency of reactive power compensation were determined on the considered example of the electric network. According to current regulatory documents, reactive flows of a certain amount from the networks of supply organizations to the network of consumers require their payment or the use of means of compensation for these flows. In addition, reactive flows limit the bandwidth of electrical power networks. In order to increase the efficiency of electricity consumption and the throughput of electrical power networks, an algorithm for the operation of the CU and an assessment of the economic efficiency of its operation is proposed.

Due to the complementary operational features, photovoltaic (PV) and fuel cell (FC) systems are increasingly being integrated into hybrid microgrids. PV systems provide clean energy during the day, while FCs provide continuous power supply throughout the day and night; thus, FCs can address PV’s incapacity during the night. However, voltage instability, frequency deviation, and enhanced harmonic distortion can result from the intrinsic intermittency of solar energy, switching errors in power electronic equipment, and varying load demands. Thus, a fuzzy logic-based current-controlled voltage source inverter (CC-VSI) is proposed in this paper to overcome these issues and enhance power quality in PV-FC hybrid microgrids. As per IEEE 1547 regulations, the fuzzy controller dynamically modifies the inverter current to maintain steady voltage and frequency profiles. MATLAB/Simulink (R2022a) is used to model and simulate the system, and its performance is evaluated under various reactive load scenarios. To test the efficacy of the proposed control technique, various power quality metrics, viz., voltage profiles (sag and swell), frequency profile, and total harmonic distortions, are plotted when subjected to large reactive load variations. The simulation results that are obtained with the proposed fuzzy-based current control technique are compared with the conventional artificial neural networks-based controller to verify the effectiveness. From the comparison study, it is found that the proposed technique shows superior power quality performance over the conventional technique. This encourages the development of renewable energy-based sustainable hybrid microgrids worldwide.

This paper examines the features of in-station optimization of reactive power operating modes at power plants whose power units are connected to distribution devices of two different voltage classes with autotransformers. For such power plants, a methodology and mathematical model have been developed for the comprehensive optimization of distribution of reactive load among power units and reactive power flow through autotransformers. The proposed methodology and mathematical model incorporate the technical and economic characteristics, the maximum and minimum constraints, active power losses in generators, block transformers, auxiliary transformers, and autotransformers, as well as the power supply schemes for the auxiliary needs of the power plant. A detailed description of the implementation metholodgy for the comprehensive optimization of distribution of reactive load among power units connected to distribution devices of two different voltage classes, as well as reactive power flow through autotransformers are provided. Its application enables the determination of the optimal value of reactive power for each of the parallel-operating power units and reactive power flow through autotransformers to ensure the minimum level of active power losses of a power plant as a whole. Calculations of the in-station active power losses at a power plant with generators possessing a nominal capacity of 200 MW connected to 220 kV and 330 kV distribution devices with 220/330 kV autotransformers have been conducted. The obtained results confirm the economic efficiency of the developed methodology. References 10, figures 2.

Green energy supply can be achieved by integrating intermittent renewable energy resources into the electrical distribution network. The intermittent nature of solar power generation presents significant technical challenges for integration that affect the network reliability and stability in relation to the grid power quality and voltage profile. Maximum utilization of photovoltaic in the electrical distribution network requires siting and sizing optimization. Distribution and transmission lines incur voltage drops and power losses due to their reactive and resistive properties. Application of evolutionary optimization techniques is adopted for optimal photovoltaic distributed generations placement in an electrical distribution network. Improved network voltage profile and system reliability was achieved by the application of particle swarm optimization algorithm to minimize the system’s power losses in a radial distribution network-IEEE 33-bus system. This was achieved through a MATLAB code implementation, with validation of the solution techniques and the developed model realized through a genetic algorithm case study. The active and reactive total loads linked to the network test system were 3.720 MW and 2.310 MVAr, accordingly. The conversion of solar power was modeled at a constant power factor with cut-off solar radiation ≥ 4.0 kWh/m2/day under normal operating conditions. As an initial configuration, active and reactive power losses were found as 211.02 kW and 143.04 kVAr without photovoltaic distributed generation at 0.85 pf, respectively. Integration of solar distributed generations at optimal location and capacity resulted in reduction of the network power losses by 57.98% reactive and 61.60% active. Improvement in voltage profile attained was 8.46%, while the ASAI network reliability index value before integrating solar source was 0.99734 p.u. but improved by 1.82% on installation. In conclusion, the system’s power losses reduced as acceptable voltage profile was maintained for sustained distribution network reliability.

Reactive power can have a range of negative impacts on energy generation and consumption in a power system network. These include creating unnecessary increases in generation, leading to the overall decline in grid efficiency and significant resource inefficiencies. Reactive power compensation is, therefore, critical for improved system performance and elevated productivity. This research aims to design and simulate a 3-phase reactive power compensation model using a Static Synchronous Compensator (STATCOM) to improve the system’s power factor and effectively suppress the system harmonics. This is implemented using MATLAB/Simulink software in which the STATCOM is connected to a 3-phase load system fed from a 500 kVA, 11kV/400V source. Based on an instantaneous reactive power (IRPT) theory, the load reactive power is harnessed to generate an inverted signal that will drive the gates of the semiconductor devices of the STATCOM inverter to cancel out the reactive current consumed by the load. Initially, a purely resistive load is connected to the system, where the model response is observed through the Simulink display blocks. Subsequently, an incremental amount of reactive load is added in three steps: 4126 Var, 8576 Var and 13470 Var, respectively. In each case, the model's response is observed and analyzed. The results show that the model can instantly generate and compensate for the equivalent load reactive power, improving the power factor from 0.87, 0.84 and 0.81, respectively, to 1.0. Using a Fast Fourier Transform (FFT) signal analyzer, the system’s total harmonic distortion (THD) is improved from 14.22% to 0.22%. This conforms to the IEEE 519 standard limit of 5.0%.

Reactive power can have a range of negative impacts on energy generation and consumption in a power system network. These include creating unnecessary increases in generation, leading to the overall decline in grid efficiency and a drastic waste of resources. Reactive power compensation is, therefore, critical for improved system performance and elevated productivity. This research aims to design and simulate a three-phase reactive power compensation model using a Static Synchronous Compensator (STATCOM) that can improve the system’s power factor and can also provide effective suppression of the system harmonics. This will be implemented using MATLAB/Simulink software in which the STATCOM will be connected to a 3-phase load system fed from 5kVA, 11kV/400V source. Based on an Instantaneous Reactive power (IRP) theory, the load reactive power is harnessed to generate an inverted signal which will drive the gates of semiconductor devices of the STATCOM inverter to cancel out the reactive current consumed by the load. Initially, a purely resistive load is connected to the system where the model response is observed through the Simulink display blocks. Subsequently, an incremental amount of reactive load is added in three steps: 4126 Var, 8576 Var and 13470 Var respectively. In each case, the response of the model is observed and analyzed. Conclusively, the designed model can instantly generate a compensating power with an ideal unit power factor in each case. Using a Fast Fourier Transform (FFT) signal analyzer, the outcome of the harmonic distortion imposed by the load currents has also been eliminated.

The extensive research on dynamic security assessment stability prediction has focused on data preprocessing techniques to improve accuracy because it was assumed that high-resolution postfault data exist. For practical users, the acquisition and application of high-resolution measurement data present significant challenges. Installing phasor measurement units on all power system nodes is deemed impractical due to high costs. In this work, we aimed to develop a rotor angle stability prediction model using steady-state data that can be easily generated from the current energy management system. Note that the steady-state measurement data refer to a pre-contingency operation condition characterized by real and reactive loads, generation levels, flows, as well as voltages and angles. The proposed framework comprises three stages: it finds physical meaning from the extended equal-area criterion to move away from the black-box approach, proposes a feature data extraction strategy to reduce the dimensionality of the input space in the support vector machine, and partition time-series power flow data by month to consider system topology changes. By utilizing 5-min-interval power flow data, unstable cases are determined, and two main feature data are extracted to train the support vector machine. The obtained results showed the effectiveness of the proposed framework in responding to a critical line fault event in real time.

This paper proposes a multi-grade reactive power utilization evaluation strategy for distribution networks with high renewables to identify the devices with low-grade utilization efficiency. Firstly, a suitability assessment indicator is presented to quantify the mismatch degree between reactive power demand and compensation capacity in distribution substations, and then a Kantorovich distance-based scenario reduction method is used to obtain typical reactive power load curves from historical data. Furthermore, influence factors on reactive power planning are investigated for distribution networks with different penetration level of renewable energy sources. Finally, considering zonal differences in load types and network structures, a multi-grade utilization evaluation strategy is proposed to identify inefficient reactive power equipment under various operating conditions. Comparative case studies have validated the superior performance of the proposed strategy for better utilization of reactive power compensation equipment.

Abstract This work describes the design process of a single-pole double-throw (SPDT) microwave switch operating at Ka-band. It is tailored to a tunable reflective termination design that can be used in tunable power amplifier configurations. A high electron mobility transistor and a resonating network are employed in shunt configuration to enhance the performance in the output port’s active and inactive conditions. The small and large signal measurements showcase a 2 GHz bandwidth with an insertion loss and isolation better than −1.8 dB and −25 dB, respectively, and handling power levels of up to 3 W at 30.5 GHz. The load-pull measurements across the entire Smith chart offer comprehensive insights into the behavior of the SPDT when operating with complex and reactive loads, fulfilling the purpose of tunable reactive termination.

At present, the main method of detecting defects in the continuity of dielectric pipes coatings in in-line production is the electrospark method of non-destructive testing. In this process, electrodes with a significant control area and forming a significant electrical reactive load on the high-voltage generator are used. In this case, the existing methods of equipment certification do not establish requirements for electrical load during certification. The authors of the article developed a generator of high pulse voltage of increased power on the basis of a two-stage electric charge accumulator, calculated the main parameters of the generator of high voltage, gave recommendations for supplementing the existing methods of certification requirements for equivalent electrical loads, showed the influence of equivalent electrical capacitance and resistance of the system ‘electrode– dielectric coating–conductive base’ on the pulse and DC test voltage of the method. The process of electrospark testing of pipes under field conditions and in-line production conditions considered by the authors has shown a significant dependence of the test voltage of the method on the load impedance of the system ‘electrode–dielectric coating–conductive base’. In this case, the technical solution proposed by the authors to increase the rate of charge accumulation in the electrical capacitance of the pumping stage and increase the power of the transformer unit allow to provide the test voltage required by the normative documentation in the process of testing. The authors point out the necessity of certification of electrospark flaw detectors at those objects where they are used in a set with the electrodes used, which is especially important for the systems of automated control of pipes coatings continuity. For cases of using electrodes of increased capacity (with increased overlap length l or diameter of controlled pipes D from 1420 mm) the authors suggest using several high-voltage generators working at some distance from each other.

One of the major problems of the operators of electricity networks is the operation of the network during events. Events with high impact and low probability of occurrence are a type of events that can cause severe disruptions in power grids. Therefore, the power grid must be resilient in dealing with such events. In recent years, electricity network operators have tried to improve the conditions of using distribution networks by using methods called flexibility. This paper aims to use flexible methods, such as energy storage systems and demand response programs to increase resiliency, reduce costs, and level the power exchange curve with the sub‐distribution substation. Therefore, first, the modeling of energy storage systems and demand response programs is presented in the energy management problem. Then, the mentioned models are integrated with the problem of the resilient operation of the two‐way distribution network. Also, considering the parameters of active and reactive loads and active generation of wind and solar renewable energy resources, uncertainty is considered in the problem. The resilient operation model has been considered and rewritten again, considering the robust optimization method for modeling uncertainties. Finally, a resiliency index is provided to show the resiliency of a network in a relative manner. In the proposed model, the simulation is done on IEEE 33‐bus network in four states and six cases. The states considered include grid operation without energy storage systems and demand response programs, operation with energy storage systems, operation with demand response programs, and operation with the simultaneous presence of energy storage systems and demand response programs. Also, in this paper, six cases include operation in normal conditions for comparison with other cases, operation in outage conditions of one‐way and two‐way busses connected to the sub‐distribution substation, operations in disconnection of some local resources, and network lines have been investigated. The results obtained from this research indicate the improvement of resiliency conditions using the method considered.