Active Power Research Articles

Research on Phase Angle Correction Control Strategy for Grid-Forming Cluster in Distributed Energy Resources

The active power-phase angle droop control avoids the frequency deviation problem caused by taking the frequency as the droop variable. However, the active power output of distributed generations (DGs) can only be allocated by adjusting the droop coefficient, and the reference value of active power output cannot be set arbitrarily. In this paper, a phase angle correction module attached to the active power-phase angle droop control is proposed. This correction module is based on the real-time data of the voltage and phase angle of the node at the generation end and the transmission end of the grid, and directly changes the phase angle reference value of the active power-phase angle droop control output. The correction can make the phase angle reference value reach the phase angle value corresponding to the active power reference value without changing the actual characteristics of the droop control, so as to adjust the active power output of the converter to reach the active power reference value. Finally, the feasibility of the correction method in different cases is verified by Matlab 23.2.0.2365128 (R2023b)/Simulink simulation.

Multi-Objective Coordinated Optimization Method of Active and Reactive Power Considering Power Characteristics of Renewable Energy Converters

In new power systems with a high proportion of renewable energy, optimization criteria based solely on economic efficiency or system stability may lead to a reduction in the static stability domain of the system or lead to long-term deviations from economic operation, thus reducing the overall applicability of such methods. This paper proposes a multi-objective active–reactive power coordinated optimization model that considers both economic efficiency and static stability indicators. The goal of the model is to minimize operating costs while optimizing static stability margins. It combines the reactive power support capabilities of converters and other reactive power compensation equipment to ensure safe and economical dispatch of the system. The proposed method is verified through a case study, which shows that this method can make full use of the potential reactive power regulation capability of the converter. At the same time, the economics and stability of the system are significantly improved by using this method. The overall improvement is about is 12.3%.

Physical Abuse Cases at Boarding Schools: Phenomena and Its Prevention Model

This research elaborates factors that contribute to physical abuse cases at Boarding Schools, which explained with routine activity theory and power relation theory. Besides, this research also evaluates the Minister of Education and Culture Regulation Number 82 Year 2015 On Prevention and Countermeasures of Violence in Education Unit Environment, and Law No. 18 Year 2019 on Boarding schools. Physical abuse cases that occur at Boarding schools are caused by excessive discipline implementation. Therefore, this encourages and motivates senior boarders or boarding caretaker to commit violence. This research uses qualitative method, with a live interview held at a boarding school which experiencing physical abuse cases causing loss of life. Delphi method is also used to deepen the prevention model and generate education expert insights focusing on the educational development of boarding school. This research is unveiling the extraordinary causes of violence and resulting on validated prevention model by education experts in boarding schools.

Within- and between therapist variability in movement and physiological synchrony and its effects on symptom change.

The predictive power of movement and electrodermal activity (EDA) synchrony has been demonstrated in various studies. Although most studies have examined each synchrony modality separately, a growing interest in the simultaneous investigation of multiple modalities has emerged. Previous research has demonstrated the importance of disentangling within and between-dyad effects, however within and between-therapist effects have yet to be investigated. The aim of the present study was to test whether movement and EDA synchrony (measured both within and between therapists) predict across-session symptom change in two types of interventions (emotion-focused vs. cognitive). The results are based on 990 session segments of 90 clients with test anxiety who were treated with a six-session treatment program by 22 therapists, treating 3-15 clients each. Movement synchrony (on the basis of motion energy analysis (MEA) values) and EDA synchrony were quantified using cross-correlations. Symptom severity was assessed before each session using the state test anxiety measure. Movement and EDA synchrony correlated negatively (-0.19, p < .001). Moreover, higher movement synchrony as well as an interaction between movement and EDA synchrony was significantly associated with symptom improvement within, but not between therapists. In addition, an interaction between EDA synchrony and cognitive (versus emotion-focused) interventions was significantly associated with symptom improvement. These results provide initial evidence that therapists' average levels of synchrony may matter less than how synchronous they are with a specific client.

Artificial intelligent fuzzy control and LAPO algorithm for enhancement LVRT and power quality of grid connected PV/wind hybrid systems

Low Voltage Ride Through (LVRT) is considered one of the main and serious problems facing the electrical grid. It occurs due to three-phase symmetric faults and asymmetric faults such as a double line to ground fault that applies in this system. This paper applies Static Synchronous Compensators (STATCOM) to improve the LVRT capability and dynamic performance of an electrical grid linked to a Photovoltaic (PV)/Wind hybrid system through grid disturbances. A hybrid power system containing a PV station that produces 1 MW and a wind farm from type Doubly Fed Induction Generator (DFIG) that produces 9 MW is connected to STATCOM with 48 pulses at PCC bus and energized load. It compensates reactive power to improve LVRT that occurred due to fault. The applied STATCOM controller adjusts the voltage of the PCC bus during an occuring fault on the grid by compensating reactive power. STATCOM is controlled by a Proportional–Integral–Derivative (PID) and is compared with STATCOM controlled by Artificial Intelligence Control (AIC)-based on Proportional—Integral Fuzzy Logic Control (PI FLC). The Lightning Attachment Procedure Optimization Algorithm (LAPO) optimization method is used to adjust the parameters of the PI controller to reduce error signals. A simulation model of the suggested hybrid power system has been performed using Matlab/Simulink. The simulation results of STATCOM proved powerful and the effectiveness of STATCOM with PI FLC in reducing voltage dip, compensating active power of wind and PV farm, protecting DC-link voltage of PV and wind from overvoltage and oscillation that happens at three-phase fault and double line to ground fault as compared with PID STATCOM in enhancement LVRT capability, and power quality.

Energy Enhancement for Grid Connection by Boost Inverter in Tripolar Operation with Novelty Quadcoupling Control

In this paper a single-phase differential boost inverter is presented that has two functions, first is boost up and second is active power quadcoupling without adding active power electronics components for smart grid system. There are three operating principals: First is pulse energy modulation which operates converter in continuous conduction mode (CCM), Second is quadcoupler which is designed by adding four boost converters and third is Tripolar technique which used to add two inductors and one capacitor for each boost converter. The proposed model consist of four boost converters in parallel with interleaving switching technique to get lower duty cycle. The energy is delivered to the quadcoupler through tripolar technique. When two grids are connected through DC to AC conversion the boost inverter can increase voltages on required demand. A Simulink model is designed that shows and proves properties of proposed system with high energy, high efficiency and power control with lower voltage stress.

Asymmetric fluctuations and self-folding of active interfaces

We study the structure and dynamics of the interface separating a passive fluid from a microtubule-based active fluid. Turbulent-like active flows power giant interfacial fluctuations, which exhibit pronounced asymmetry between regions of positive and negative curvature. Experiments, numerical simulations, and theoretical arguments reveal how the interface breaks up the spatial symmetry of the fundamental bend instability to generate local vortical flows that lead to asymmetric interface fluctuations. The magnitude of interface deformations increases with activity: In the high activity limit, the interface self-folds invaginating passive droplets and generating a foam-like phase, where active fluid is perforated with passive droplets. These results demonstrate how active stresses control the structure, dynamics, and break-up of soft, deformable, and reconfigurable liquid-liquid interfaces.

Adaptive Approach for Power Oscillation Damping using STATCOM

In this paper we had described the designing of a Power Oscillation Damping (POD) controller for a Static Synchronous Compensator (STATCOM) equipped with Energy Storage System (ESS). Various adaptive techniques like fuzzy logic controller, PID controller, algorithm, etc. can be employed to achieve this allowing a fast and adaptive approximation of the low-frequency electromechanical oscillations from locally measured signals during power system disturbances. We developed an approach using variable DC voltage control and constant modulation index method; which are effective in increasing the damping of the system at the concerned frequencies and in case of system parameter uncertainties. A control policy that optimizes active and reactive power inoculation at various connection points of the STATCOM is derived using the simplified model in MATLAB Simulink using impower system toolbox. Signal analysis of the dynamic performance of the proposed control strategy is carried out. To verify the effectiveness of the proposed control method, we carried out simulations and found that the approach provides oscillation damping irrespective of the connection point of the device and also in the presence of system parameter uncertainties.

Series Active Power Filter for Power Quality Improvement

The paper discusses the theoretical framework and operating principles of the SAPF, including its control strategies based on instantaneous reactive power theory and synchronous reference frame theory. The design criteria for the SAPF components, such as the voltage source inverter, DC link capacitor, and coupling transformer, are also elaborated to ensure optimal performance. Simulation studies using MATLAB/Simulink are conducted to evaluate the effectiveness of the proposed SAPF under various power quality disturbance scenarios. The results demonstrate that the SAPF effectively compensates for voltage sags, swells, and harmonics, maintaining voltage stability and reducing total harmonic distortion (THD) to within acceptable standards. Additionally, a prototype of the SAPF is developed and tested in a laboratory environment, confirming the simulation results and showcasing the practical feasibility of the solution. The study concludes that the Series Active Power Filter is a robust and versatile solution for power quality improvement in modern electrical distribution systems. Future work may involve exploring hybrid configurations combining series and parallel active filters for comprehensive power quality management and the development of advanced control algorithms for enhanced performance under dynamic load conditions.

Assessment of transmission network connection solutions based on HVAC for offshore wind

AbstractThe diffusion of offshore wind power plants (OWPPs), useful to fulfil renewable diffusion policy targets, implies several technological challenges for integration in power transmission network. The definition of the OWPP connection to the transmission network affects possible exploitation of the assets, involves an evaluation of active power losses and loadability and points out the need for compensation devices, in order to comply with connection rules fixed by the grid operator. This paper proposes a methodology to determine the most suitable electric connection for an OWPP based on high‐voltage alternating current (HVAC) cables, for providing indications for transmission system operators. In particular, different HVAC connection schemes for OWPPs are analysed, focusing on new 66 kV standard voltage and high‐voltage levels, providing technical insight on transmission cable optimal operation conditions. An economic analysis is carried out by proper estimation of construction costs and production forecast, accounting for active power losses and reliability impact. The most suitable connection solution depending on OWPP size and distance in Italian framework is evaluated by means of synthetic techno‐economic indicators, further analysing possible sensitivities of energy price and capacity factor.

Optimal control of grid-connected overvoltage of distributed photovoltaic power generation based on cluster division

To address the overvoltage problem caused by the reverse flow of current when a high proportion of distributed photovoltaic (PV) is connected to the distribution network, this paper proposes a grid-connected voltage regulation control strategy based on the cluster division of the Distributed Model Predictive Control (DMPC) algorithm. Firstly, the overvoltage responsibility of each node is calculated using the Shapley value method. This is combined with k-means clustering to achieve effective cluster division, enabling dynamic adjustment of the active and reactive power of photovoltaic power generation units to stabilize regional voltage. Secondly, a group grid-connected voltage control strategy is introduced. This strategy controls the active and reactive power outputs by integrating real-time power output and voltage information from PV generating units in the region with the DMPC algorithm, ensuring overall voltage stability of the grid-connected system. Finally, actual overvoltage data from a 10 kV distribution line in the Dingxi power grid, Gansu Province, is used to verify that under the proposed control strategy, PV grid-connected overvoltage nodes are maintained within 1.06 p.u. The control effect is improved by a margin of 0.05 compared to traditional control methods. This demonstrates the effectiveness of the grouped grid-connected voltage regulation control strategy, achieving smoother voltage regulation performance in distributed PV grid-connected systems.

Ancillary Services to Mitigate Non-linear and Unbalanced Load Based on CPT Using a DFIG Power Plant

The increase of renewable energy sources and non-linear loads on the utility grid introduces challenges in maintaining the nominal conditions of the utility grid. A viable approach to addressing some of these challenges is to utilize renewable energy conversion systems that accomplish supplementary functions in addition to supplying active power. This paper presents the implementation of ancillary services to mitigate non-linear and unbalanced loads using a single Doubly Fed Induction Generation (DFIG) power plant. For this, the Conservative Power Theory (CPT) is used to provide three types of services simultaneously: active filtering, reactive power compensation, and unbalanced phase compensation. A back-to-back converter is used to control the power flow in the DFIG and employ ancillary services. Two control strategies are compared: in the dq reference frame and the $\alpha \beta$ reference frame. Simulations in MatLab/Simulink are used to evaluate the response of the CPT and the control strategies. The ancillary services performance is analyzed using the indicator based on standards and CPT factor. The results show that the indicators comply with the standards depending on the active power supply. Moreover, $\alpha\beta$ reference frame exhibits better performance than $dq$ reference frame.

HIL Test Verification of PDPI Control of Induction Generator‐Based Multi‐Rotor Wind Turbine Systems

ABSTRACTIn this experimental study, a new technique is designed and presented for controlling the rotor side converter of an induction generator (IG) for multi‐rotor wind turbine (MRWT) systems. The direct power command (DPC) strategy is used to regulate the reactive and active power (Qs and Ps). DPC is characterized by several drawbacks, the most prominent of which are low durability, low current/power quality, and the use of power estimation. Therefore, a new PDPI (proportional‐derivative proportional‐integral) regulator is used as a suitable solution to overcome these shortcomings while maintaining simplicity, achieving a rapid dynamic response, and obtaining gains that characterize the DPC. The suggested DPC for controlling the IG inverter of an MRWT system uses two PDPI regulators and pulse width modulation (PWM) to create and generate the pulses necessary to run and regulate the IG inverter. First, the DPC‐PDPI‐PWM is verified in a MATLAB using different tests, and the characteristics of the DPC‐PDPI‐PWM is compared to that of DPC under different working conditions for a 1500 kW IG. Second, the validity of the simulated results is verified using the Hardware‐in‐the loop (HIL) test for the DPC‐PDPI‐PWM, and dSPACE 1104 is used for this purpose. The results demonstrate the effectiveness of the DPC‐PDPI‐PWM approach over DPC, as the harmonic distortion of the stream is minimized by 36.66%, 22.68%, and 33.33% in the three proposed tests. Also, the overshoot value of Ps was reduced compared to DPC by ratios estimated at 70.96%, 71.42%, and 70.31% in all tests. DPC‐PDPI‐PWM also reduces the steady‐state error of Qs compared to DPC by 68.33%, 58.82%, 67.90% in all tests performed. The experimental results confirm the numerical results, suggesting that the DPC‐PDPI‐PWM is a suitable solution in the field of command in the future.

Optimal reconfiguration of a distribution network integrated photovoltaic and wind systems using blood-sucking leech optimizer

This paper presents a planning strategy for integrating renewable distributed generation (DG) units into a distribution network, incorporating network reconfiguration to enhance the network's technical, economic, and environmental performance. Utilizing a novel meta-heuristic algorithm, the Blood-Sucking Leech Optimizer (BSLO), the study addresses a multi-objective optimization problem aimed at determining the optimal placement and sizing of DG units, as well as the most effective network topology. This approach seeks to minimize active power losses, improve voltage profiles, reduce installation costs, and lower greenhouse gas emissions. The model accounts for variable load demands, climatic factors (such as ambient temperature, solar irradiation, and wind speed), and fluctuating energy prices, reflecting realistic operating conditions. Tested on the IEEE 69-bus distribution network, the BSLO algorithm demonstrated rapid convergence to the global optimum by effectively balancing exploration and exploitation phases. Compared to other meta-heuristic methods, such as the Grey Wolf Optimizer, Gorilla Troops Optimizer, Walrus Optimization Algorithm, and Artificial Hummingbird Algorithm, the BSLO consistently achieved superior accuracy and faster convergence, resulting in higher precision and optimization efficiency. The optimal deployment of two PV generators and two wind turbines, combined with selective line switch openings, resulted in an 87.66% reduction in active power losses, a 73.30% decrease in voltage deviation, a 51.91% reduction in overall system costs, and a 62.74% decrease in greenhouse gas emissions compared to the base case.

Prefrontal serotonin depletion delays reversal learning and increases theta synchronization of the infralimbic-prelimbic-orbitofrontal prefrontal cortex circuit.

Prefrontal serotonin plays a role in the expression of flexible behavior during reversal learning tasks as its depletion delays reversal learning. However, the mechanisms by which serotonin modulates the prefrontal cortex functions during reversal learning remain unclear. Nevertheless, serotonin has been shown to modulate theta activity during spatial learning and memory. We evaluated the effects of prefrontal serotonin depletion on theta activity in the prefrontal infralimbic, prelimbic, and orbitofrontal (IL, PL, and OFC) subregions of male rats during a spatial reversal learning task in an aquatic T-maze. Prefrontal serotonin depletion delayed spatial reversal learning and increased theta activity power in the PL and OFC. Furthermore, animals with serotonin depletion had increased functional coupling between the OFC and the IL and PL cortices compared with the control group. These results indicate that serotonin regulates reversal learning through modulation of prefrontal theta activity by tuning both the power and functional synchronization of the prefrontal subregions.

Experimental Tests and Simulations About The Efficiency of Commercial Hybrid Inverters Operating at Variable Power Factor

The need to ‘rethink’ the concept of Distribution, both at the planning and operational levels, arises from the emergence of the Distributed Generation paradigm, mostly installed in LV networks. The existing arrangements for the management, protection and control of distribution networks are typically inadequate for this ever-increasing presence of Distributed Generation. Consequently, national and international grid codes have been updated requiring distributed generators to be involved in grid control by supplying ancillary services, such as the voltage and frequency regulation. In this context, the Italian Standards, and in particular the CEI 0–21, require hybrid inverters of residential systems, which are usually only setup to supply active power at unity power factor, to include also the possibility of being able to absorb or supply reactive energy. This allows to limit the over / under voltages problems. To this aim, the inverter manufacturers have introduced the possibility for residential inverters to set the power factor. These new capabilities have been exploited in this paper in order to study the inverter performance with the variation of the power factor, considering both the inductive and the capacitive behaviour. In particular, the presented paper focuses on experimental tests on a hybrid inverter-based system for residential use with the aim of evaluating the dependence of the inverter efficiency on the power factor. Based on measured values, a Matlab/Simulink simulator has been developed for modelling the system, using the found dependence. The main aim is to evaluate the inverter control systems in order to participate in regulation services and to evaluate the inverter efficiency in case of a power factor different from unity.

Control Strategy for Power Fluctuation Smoothing at Distribution Network Substations Considering Multiple Types of Adjustment Resources

With the proposal of the dual carbon target, the distributed photovoltaic (PV) industry has rapidly developed in recent years. However, the randomness and volatility of photovoltaic energy can be transmitted to the main grid through distribution network substations, posing challenges to the stable operation of the power system. Therefore, this paper considers tapping into the regulation potential of feeder loads on the distribution network side, as well as distributed energy storage and distributed PV resources, to enhance the grid’s control methods. A power fluctuation smoothing control strategy for substations in distribution networks, accounting for multiple types of regulation resources, is proposed. In the day-ahead stage, traditional voltage regulation devices such as the OLTC (on-load tap changer) and CB (circuit breaker) are pre-dispatched based on source–load forecasts, optimizing the fluctuation range of substation power and the number of device operations. This provides optimal substation power values for day-to-day optimization. During the intraday phase, fast regulation devices such as PV (photovoltaic), SVC (static var compensator), and energy storage systems are coordinated, and an optimization model is established with the goal of reducing power curtailment while closely tracking substation trends. This model quickly calculates the active power regulation and device operations of various adjustable resources, improving the economic efficiency of the distribution network system while achieving power fluctuation smoothing at the substation level. Finally, the feasibility and effectiveness of the power fluctuation smoothing control model are verified through simulations on an improved standard distribution system.

Power Flow Control with a Single Stage Grid Connected Pv Mechanism with a Multilevel Inverter

There is potential to feed excess electricity to the grid for more efficient and cost-effective power utilization when solar PV arrays are installed widely in comparison to other renewable power output. The primary objective of this article is to use a multilevel inverter to operate autonomously regulate the active and reactive power flow. A vector control system that rotates synchronously with the grid frequency has been devised in both direct and quadrature reference frames. Two current control loops have been implemented to control the current delivered to the grid so that it will has low total harmonic distortion and is in phase with the grid voltage. To run the inverter at a suitable DC link voltage which corresponds to maximum power-which is established by the MPPT algorithm, a DC voltage control loop has also been implemented. Inverters that are connected to the grid are commonly utilized to enhance dispersed generation and power eminence.

A high effectiveness impact‐optimized piezoelectric energy harvesting interface system

AbstractThis paper presents a novel high‐performance impact‐optimized interface system for an impact‐driven piezoelectric energy harvester (PEH) which utilizes two independent parallel harvesting plans, that is, low‐efficiency self‐powered passive path and high‐efficiency active maximum power point tracking (MPPT)‐based path, for different situations based on the characteristics of the input excitation and stored energy content which are evaluated by the mode detection unit. It uses a synchronous electrical charge extraction‐based self‐powered passive circuit as a primary energy extraction strategy. Thus, the proposed structure is self‐sustained with cold start capability. When the determined prerequisites are met, the system switches to the secondary energy extraction strategy, that is, high‐efficiency MPPT‐based path, in which during the maximum power point sensing phase, the PEH is sensed without disconnecting it from the interface and during the maximum power point setting phase, a bidirectional DC/DC converter performs a fully bidirectional energy transfer, increasing the extraction efficiency. The proposed system is designed and simulated using standard 180 nm complementary metal‐oxide semiconductor (CMOS) technology. Post‐layout simulation results show that when the input energy content is around 50 µJ, the FoMMOPIR, periodic harvesting efficiency, shock harvesting efficiency, MPPT efficiency, and effectiveness of the proposed system are 505%, 65%, 80%, 70%, and 56%, respectively.

Integrated optimization for sizing, placement, and energy management of hybrid energy storage systems in renewable power systems

Power systems reliant on renewable energy sources (RES) encounter supply-demand imbalances and stability challenges due to their inherent uncertainties. Hybrid energy storage systems (HESS) have emerged as a flexible and cost-effective solution to address these issues. This paper proposes an integrated optimization method for the capacity, location, and energy management of a HESS in RES-based power systems. The method optimizes battery energy storage system (BESS), electrolyzer (EL), fuel cell (FC), and hydrogen storage tank (HST) to minimize total costs, including power purchase, curtailment compensation, operation and maintenance (O&M), and investment costs, alongside voltage profile deviation index (VPDI) and active power loss index (APLI). A novel hybrid framework is proposed, utilizing mixed-integer linear programming (MILP) optimization at the master level and non-dominated sorting genetic algorithm II (NSGA-II) optimization at the slave level. This framework ensures that MILP provides robust solutions, while NSGA-II derives balanced optimal solutions from the optimal Pareto front. The proposed method was validated using real seasonal data from Korea and tested in IEEE 33 and IEEE 69 bus systems against various benchmark cases. Results indicate significant improvements, with VPDI enhanced by 16.00 % and 10.11 %, APLI by 15.64 % and 12.15 %, and total costs reduced by 58.67 % and 50.56 %, respectively. The sensitivity analysis demonstrated the robustness of the proposed method, showing zero sensitivity to iterations and positive correlations with increased levels of RES. Further verification against other optimization algorithms showed that the proposed method excels in cost efficiency, voltage stability, and line loss reduction, providing highly reliable results.