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This paper attempts to provide a clear explanation of how the concept of double frequency complex plane is applied to the calculation of complex electrical power. This is a step to remove the confusion associated with the calculation of complex electrical power that has persisted in the scientific community to this day. It starts with a discussion on the conventional method of calculation of complex power and its relation with the Steinmetz’s original method of power calculation in steady state AC circuit. An excerpt from the writing of Steinmetz is then included in which he enumerated mathematical equations that were used to make adjustments while calculating two times the supply frequency complex electrical power from the supply frequency complex voltage and current. Since the equations appear to contradict the laws of conventional complex algebra, considerable confusion arose soon after the Steinmetz’s publication. This confusion persists even today. Usual text books do not touch upon this issue and merely describe the mathematical equation required for calculation of complex power. This paper tries to provide a justification behind the adjustment equations involving double frequency complex plane used for complex power calculation through a simple R-L circuit and provide analytical explanation of the equations enumerated by Steinmetz. [ABSTRACT FROM AUTHOR]

Oscillations, commonly known as a universal, propagative, and intricate event in the new power system, often give rise to generator tripping and load shedding, not only adversely affecting the power flow limit and the power angle stability but also posing threats to the lines of defense for stability and protection. Traditionally, emphasis has been laid on post-fault oscillation management, an emergency measure to deal with the impact and damage that have already affected the power grid. As such, this paper focuses on an oscillation prediction technique to detect oscillation energy early and intervene proactively to prevent further faults. This technique effectively lessens the damage caused by impacts and disconnects to the power grid. Firstly, this paper proposes the concept of disturbance power density and establishes the correlation between disturbance energy and the time domain, thereby exploring a method for evaluating the pattern of electrical quantities before power system oscillation. Secondly, it speeds up the time it takes to detect faults by catching nuances of voltage-current phase angle and impedance. Lastly, it puts forward a technique to cope with the intricacy and variety of power grid equipment using the convolutional neural network (CNN). This technique incorporates an integrated attention mechanism within a one-dimensional CNN model to capture the implicit mapping between voltage, active power, and reactive power at any time in the power system. This enables the model to self-learn multi-device characteristics and enhances the possibility of using theory in practical ways. Moreover, practical case studies also show that the prediction technique proposed in this paper can effectively issue warnings eight minutes before the occurrence of oscillation. [ABSTRACT FROM AUTHOR]

The fast-growing influence of grid-interfaced photovoltaic (PV) networks makes it necessary to adhere to grid-code (GC) regulations. These regulations mandate that PV systems inject active power both during and after the grid fault occurrence, as well as provide reactive current to the grid during voltage dips, in order to prevent power system stability concerns. In this context, two novel control schemes have been proposed in this paper for grid-connected photovoltaic networks that can support low-voltage ride-through (LVRT). The proposed control techniques have been demonstrated to be simple and efficient in the event of severe voltage dips, i.e., work up to a voltage drop of 90% of the nominal grid voltage. Our first approach involves an enhanced reactive current injection strategy that provides reactive power support to the power grid during voltage dips without any additional devices. The control structure is comprised of a voltage level estimator and a reactive current controller. The voltage level estimator obtains power grid voltage, while the reactive current controller computes active−reactive current commands. It is particularly noteworthy that the proposed scheme generates active current as much as possible according to the voltage dips and tracks the active current reference correctly, where conventional strategies fail to cope. The second control method for LVRT presented in this research work involves using hardware, specifically a crowbar. The use of a crowbar is the most straightforward method to provide support to the power system, bypassing over-current during voltage dips and keeping the current within the normal converter rating. The control strategies proposed in this paper are validated in MATLAB/Simulink under symmetrical and unsymmetrical severe voltage dips as well as grid voltage harmonics, and a detailed comparison study with a state-of-the-art PQ-based fault-ride-through controller has been conducted. [ABSTRACT FROM AUTHOR]

This paper introduces and underscores the automation of the E-vehicle charging process through optimization between the grid and the vehicle, incorporating real-time constraints in the charging and discharging processes. With the surge in E-vehicle usage and heightened electricity demand, automating the vehicle battery charging process becomes imperative to mitigate its impact on the grid. The research outlined in this paper focuses on automating electric vehicle charging and discharging based on real-time power demand considerations. The automation process, facilitated through a connection to the power grid, is managed by the interconnected network and algorithm-based monitoring of real-time parameters. These parameters include power, voltage, state of charge of the battery, charging cost, grid load demand, distance from the grid to the vehicle and vehicle demand. The actor-critic algorithm serves as a guide for electric vehicle charging automation, aligning with vehicle-specific data such as charging cost, vehicle demand, and grid demand to assess switching responses and enhance result accuracy. Load variations in real and reactive power for different configurations—domestic, industrial, and vehicle connections to the grid—throughout the day are considered using the IEEE 33 standard bus system. Frequency analysis of vehicle charging, grid stability analysis, and evaluation of voltage sag and swell during faulty conditions are conducted with MATLAB and the IEEE 33 standard bus system. The results provide insights into the switching time for the charging process based on algorithmic guidelines, ensuring the process follows the correct trajectory. The study demonstrates that charging time and cost are directly proportional to demand, even in time-varying processes. In the course of this research, an embedded hardware prototype model was developed to implement the proposed concept of E-vehicle charging automation. [ABSTRACT FROM AUTHOR]

With the intensification of ocean exploration and development in recent years, the navigation equipment in the marine environment has become increasingly diversified, making the marine environment more complex. Traditional methods for underwater target recognition are gradually becoming less applicable and unable to achieve better results. With the application of deep learning in underwater target recognition, the robustness of deep learning models used for underwater target recognition is crucial due to the significant environmental interference in underwater target data and the susceptibility of deep learning models to adversarial samples. This paper proposes an error sample feature compensation method for improving the robustness of deep learning models for underwater target recognition, focusing on the problem of the significant impact of sample data quality on the robustness of deep learning models for underwater target recognition. The method innovatively divides error samples into difficult-to-improve samples and easy-to-improve samples and proposes an adversarial training method combined with classification conditions. At the same time, the method uses a weighted index of model accuracy to combine adversarial training models with feature compensation methods, further improving the robustness of deep learning models for underwater target recognition tasks. Finally, the method is validated on an underwater dataset, and the results show that the proposed method improves the robustness of deep learning models used for underwater target recognition. [ABSTRACT FROM AUTHOR]

Enhancing energy efficiency in commercial buildings is crucial for reducing energy consumption. Achieving this goal requires careful monitoring and analysis of the energy usage patterns exhibited by different devices. Nonetheless, gathering data from individual appliances in commercial buildings presents difficulties due to the large number of appliances, complex installations, and costs. This paper presents the Circuits-Level Electrical Measurements Dataset (CLEMD). The measurement was conducted at the main switchboard to a set of distribution boards instead of measuring at the individual loads. The data is gathered from an institutional setting. It consists of 42 records of vital electrical parameters including voltage, current, frequency, real power, reactive power, apparent power, power factor, and odd harmonics for electrical currents. The device deployed in the measurement were industry-grade and had a high sampling rate of 200 kHz. The measurements were done over a 40-day period, from September 16 2023 to October 25 2023. CLEMD is the first Malaysian public dataset on circuit-level electricity consumption and offers analysis opportunities in different research areas such as electricity load disaggregation at circuit level, circuit identification, load profile forecasting, and pattern recognition. [ABSTRACT FROM AUTHOR]

The increasing integration of distributed energy resources such as photovoltaic (PV) systems into distribution networks introduces intermittent and variable power, leading to high voltage fluctuations. High PV integration can also result in increased terminal voltage of the network during periods of high PV generation and low load consumption. These problems can be solved by optimal utilization of the reactive power capability of a smart inverter. However, solving the optimization problem using a detailed mathematical model of the distribution network may be time-consuming. Due to this, the optimization process may not be fast enough to incorporate this rapid fluctuation when implemented in real-time optimization. To address these issues, this paper proposes a co-simulation-based optimization approach for optimal reactive power control in smart inverters. By utilizing co-simulation, the need for detailed mathematical modeling of the power flow equation of the distribution network in the optimization model is eliminated, thereby enabling faster optimization. This paper compares three optimization algorithms (improved harmony search, simplicial homology global optimization, and differential evolution) using models developed in OpenDSS and DigSilent PowerFactory. The results demonstrate the suitability of the proposed co-simulation-based optimization for obtaining optimal setpoints for reactive power control, minimizing total power loss in distribution networks with high PV integration. This research paper contributes to efficient and practical solutions for modeling optimal control problems in future distribution networks. [ABSTRACT FROM AUTHOR]

This research paper investigates the new multilevel connections with minimum number of components as a voltage source inverter (VSI) which is connected in parallel as shunt active power filter (SAPF) for the purpose of the improving power quality and reactive power compensation in power systems. The main contribution of this paper is the design & development of modular structure which is capable of producing a wide range of output levels (9,11,13,15,17,19,21,23,25,27,29 and 31) using Asymmetric PV sources. A comparative study is made with other (27-level) reduced multilevel connection (RMC) topologies suitable for asymmetric input sources from solar photovoltaics (SPV). In addition, the state space analysis and the loss calculations are performed in order to ensure that the inverter is superior to the conventional topologies. The switching angles are determined using Particle Swarm Optimization (PSO) method. The implementation part of RMC is carried out with the selective harmonic elimination (SHE) which mitigates harmonics in the system. MATLAB/Simulink software is used for modelling of the proposed system. An Experimental setup of the proposed multilevel connections is developed and then it is experimentally investigated. A capacity of 3 KWp Solar PV system which feeds the DC input to the developed prototype. On the basis of the research findings, it is possible to draw the conclusion that the proposed inverter topology minimizes the voltage harmonics by 2.56% and current harmonics by 2.33% which enhances power quality, compensates the reactive power, lessens the number of components used by 12 and more cost effective. [ABSTRACT FROM AUTHOR]

Loss of Excitation (LOE) is the most considerable fault in Synchronous generators since it affects both the generators and power network. The traditional protection method for LOE is based on impedance trajectory of the machine with negative offset mho relay. Meanwhile the traditional method experiences malfunctions and speed dip in LOE detection. This paper presents machine learning approach to detect LOE fault as well as classification logic to discriminate LOE fault from power swing conditions due to Line fault. This paper utilizes Hotelling's-T2 statistical method to calculate Hotelling's-T2 based Fault Indices (HT2-FI) for fault detection and Support Vector Machine (SVM) for classification. The time series data of electrical quantities such as Terminal voltage and Reactive Power of the generator are extracted from simulated Single Machine Infinite Bus test system and used as input data. These data involved in calculation of HT2-FI and in development of classification logic. The proposed method is simulated and verified for complete, partial LOE conditions and power swing conditions. Simulation outcomes depict the remarkable signs of the proposed method in LOE identification from power swing. Comparative assessment also reports that the method is capable of saving time in detecting LOE. [ABSTRACT FROM AUTHOR]

Hybrid ac/dc microgrid (HMG) comprises ac and dc microgrids (MGs) interconnected through an interlinking converter (IC). In islanded operation mode of HMG, a coordinated control structure must be implemented to realize voltage and frequency control in ac MG, voltage control in dc MG, active and reactive power sharing among ac sources, active power sharing among dc sources, global active power sharing among dc and ac sources, and reactive power sharing among ac sources and IC. To realize these objectives, a new coordinated control based on master–slave approach is proposed in this paper. In this method, the master source of each MG broadcasts its relative power loading as a common signal to the slave sources of the same MG and IC through a unidirectional low-bandwidth communication network. Based on this information, the slave sources and the IC adjust their operating point. The proposed method provides accurate power sharing as well as zero voltage and frequency deviation. It does not require a centralized control unit and features plug and play capability. The derivation of the proposed method is thoroughly discussed in this paper. Time domain simulation results based on CIGRE benchmark MG are presented to validate the proposed control strategy. [ABSTRACT FROM AUTHOR]

In a DFIG grid interconnected system, the control of real and reactive power relies on various factors. This paper presents an approach to regulate the flow of real and reactive power using a Neural Tuning Machine (NTM) based on a recurrent neural network. The focus is on controlling the flow of reactive power from the rotor-side converter, which is proportional to the grid-side controller through a coupling voltage. The proposed NTM method leverages neural networks to fine-tune the parameters of the PI controller, optimizing performance for DFIG grid integration. By integrating dense plexus terminals, also known as dense connections, within the neural network, the control system achieves enhanced adaptability, robustness, and nonlinear dynamics, addressing the challenges of the grid. Grid control actions are based on the voltage profile at different bus locations, thereby regulating voltage. This article meticulously examines the analysis in terms of DFIG configuration and highlights the advantages of the neural tuning machine in controlling inner current loop parameters compared to conventional PI controllers. To demonstrate the robustness of the control algorithm, a MATLAB Simulink model is designed, and validation is conducted with three different benchmarking models. All calculations and results presented in the article strictly adhere to IEEE and IEC standards. This research contributes to advancing control methodologies for DFIG grid integration and lays the groundwork for further exploration of neural tuning methods in power system control. [ABSTRACT FROM AUTHOR]

The escalating worldwide power demand necessitates innovative solutions to address the emerging power crisis. Grid-synchronized electric vehicles (EVs) have emerged as a promising avenue for mitigating this crisis. The vehicle-to-grid technology is unique advanced smart grid concept by which the exchange of energy is allowed among grid and EV. The integration of EV and grid affects an entire power system causing imbalance in supply–demand, voltage and frequency. To minimize these issues, feasible optimization techniques are introduced in this paper. Lithium-ion batteries are initially charged via smart homes, and convolutional neural networks (CNN) are used to ascertain a battery's state of charge (SOC). A bidirectional SEPIC–zeta converter is employed in this paper by which voltage is either increased or decreased. The gating sequence for the converter is generated by means of adaptive neuro fuzzy inference system which depends on an estimated SOC. If the SOC is greater than 80%, battery is discharged using a SEPIC mode; if the SOC is lower than 80%, battery is charged by grid using the ZETA mode. By using a PI controller, active and reactive power are also controlled. Simulation results using MATLAB showcase the efficacy of the suggested approach. The bidirectional SEPIC–Zeta converter exhibits an impressive efficiency of 96% and a voltage gain ratio of 1:8 when compared to other converters. CNN-based SOC tracking achieves remarkable tracking efficiency of 92.3%, outperforming other tracking methods. The grid current total harmonic distortion is notably curtailed at 2.3%, and a power factor of 0.9 is achieved using PI-based grid synchronization. [ABSTRACT FROM AUTHOR]

This paper presents the control strategies and performance analysis of doubly fed induction generator (DFIG) for grid-connected wind energy conversion system (WECS). The wind power produces environmentally sustainable electricity and helps to meet national energy demand as the amounts of non-renewable resources are declining. The development of the WECS can be seen with development in power electronics technology. Currently, two types of major generator used in WECS these are DFIG and the permanent magnet synchronous generator (PMSG). Both variable oprational speed are used in wind turbine. Because its high performance, reliability, controllability and high-power and voltage capabilities, multilevel converters have become a popular option for multi-MW WECSs. This paper focuses on the application of back-to-back modular multilevel converters in a DFIG and PMSG-based WECS. A comparative performance analysis of the two systems based on power quality, active, reactive power, and modular multilevel converter dynamics is presented. The comparison is based on simulation results created in MATLAB/Simulink software. [ABSTRACT FROM AUTHOR]

The paper proposes a nonlinear controller called dual super-twisting sliding mode command (DSTSMC) for controlling and regulating the rotor side converter (RSC) of multi-rotor wind power systems that use doubly-fed induction generators. It was proposed that this controller be developed as an alternative to the direct power control (DPC), which makes use of a pulse width modulation (PWM) strategy to regulate the RSC's functioning. Overcoming the power/current quality issue with the proposed technique (DPC-DSTSMC-PWM) is characterized by great robustness and excellent performance. The designed strategy was contrasted with the standard method of control and other methods already in use. So, the unique proposed control strategy's robustness, performance, efficiency, and efficacy in enhancing system characteristics were tested and validated in Matlab/Simulink. In both tests, the proposed method resulted in significant improvements, reducing active power ripples by 83.33%, 57.14%, and 48.57% in the proposed tests. When compared with the traditional regulation method, the reduction rates of reactive power ripples are 64.06%, 52.47%, and 68.7% in the tests. However, in contrast to the conventional method, the proposed tests showed a decrease of between 72.46%, 50%, and 76.22% in the value of total harmonic distortion (THD) of the provided currents. These ratios show how effective the proposed plan is in ameliorating and enhancing aspects of the energy system. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are rapidly replacing conventional fuel vehicles, offering powerful, emission-free performance. This paper introduces an innovative three-phase bidirectional charger for grid-to-vehicle (G2V) and vehicle-to-grid (V2G) applications, strengthening the connection between EVs and the power grid. The charger employs a two-stage power conversion approach with advanced converters and a simplified dq-based charging control strategy. An efficient AC-DC converter facilitates smooth transitions between modes, responding to grid directives for active and reactive power. A soft-switching dual active bridge (SS-DAB) DC-DC converter optimally interfaces with the EV battery pack, while dual active LCL filters suppress harmonics, enhancing system performance. Simulated results confirm the charger's effectiveness in a 3.5-kW prototype using MATLAB/Simulink. The proposed SS-DAB converter-based bidirectional on-board charger introduces a groundbreaking unified Voltage Source Converter (VSC) control approach, enabling efficient power transfer in both vehicle-to-grid (V2G) and grid-to-vehicle (G2V) modes. This innovation ensures rapid dynamic response, exceptional steady-state performance, and robustness against grid demand changes, optimizing EV integration. [ABSTRACT FROM AUTHOR]

This paper presents new methodologies for modeling static VAr compensators (SVCs) in the power flow problem. The proposed formulations utilize sigmoid functions to model the control equations that describe the steady-state behavior of SVCs. The first methodology introduces reactive power injection as a new state variable, while the second methodology utilizes the thyristor firing angle. These steady-state SVC methodologies were applied to the power flow problem using the full Newton formulation, which incorporates the control equations into the system of nonlinear equations. One of the main contributions of these proposed methodologies is that they eliminate the need for alternating adjustments concerning the operational limits of the SVC during the iterative power flow process. The implementation of a power flow program was tested on both small-scale tutorial systems and the medium-scale IEEE Nordic system. The presented results validate and demonstrate the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

The power factor of industrial facilities is typically inductive. The case study in this paper was based on a typical Malaysian 11-kV on-grid industrial system with renewable energy sources and electric vehicle charging station connected. The integration of renewable energy sources reduces energy consumption from the grid; it consecutively reduces greenhouse gas emissions. However, the integration of renewable energy sources such as solar photovoltaic operating at unity power factor results in a reduction of the industry's power factor. According to the Malaysian Distribution Code, the power factor of a medium voltage industrial system should be more than 0.85 lagging. A long-term low power factor will reduce the related electrical equipment lifespan and increase the monthly electricity bills. A classic method to overcome this issue was by installing reactive power compensator devices, such as the synchronous condenser, static VAr compensator and static synchronous compensator. Studies had revealed that solar photovoltaic with appropriate control system design could perform short-term reactive power compensation. The control techniques used are either power factor control, active power control, reactive power control or any combination of them. However, neither the reactive power compensator devices nor the solar photovoltaic with a control system can regulate the industry's power factor to an intended value throughout its operation. Thus, this paper presents a simple, relatively cost-effective design of a master power factor controller that is capable of regulating the industry's power factor to an intended value throughout its operation with a single preset reference. In this research, an industry-grade system comprises an industrial load installed with a power factor-controlled capacitor bank, a power factor-controlled solar photovoltaic system, a bidirectional current-controlled electric vehicle charging system based on CHAdeMO 1.1 standard charging protocol and a master power factor controller was designed using the Matrix Laboratory/Simulink software. This paper has provided simulation results as proof that each of the designed equipment was functioning appropriately. The results also proved that the proposed master power factor controller was capable of regulating the power factor of the industrial system to above 0.85 lagging throughout its operation. [ABSTRACT FROM AUTHOR]

This paper demonstrates the controlling abilities of a large PV-farm as a Solar-PV inverter for mitigating the chaotic electrical, electromechanical, and torsional oscillations including Subsynchronous resonance in a turbogenerator-based power system. The oscillations include deviations in the machine speed, rotor angle, voltage fluctuations (leading to voltage collapse), and torsional modes. During the night with no solar power generation, the PV-plant switches to PV-STATCOM mode and works as a Solar-PV inverter at its full capacity to attenuate the oscillations. During full sun in the daytime, on any fault detection, the PV-plant responds instantly and stops generating power to work as a Solar-PV inverter. The PV-farm operates in the same mode until the oscillations are fully alleviated. This paper manifests the control of the DC-link capacitor voltage of the Solar-PV inverter with a bacterial foraging optimization-based intelligent maximum power point tracking controller for the optimal control of active and reactive power. Kundur's multi-machine model aggregated with PV-plant is modeled in the Matlab/Simulink environment to examine the rotor swing deviations with associated shaft segments. The results for different test cases of interest demonstrate the positive outcomes of deploying large PV-farms as a smart PV-STATCOM for controlling power system oscillations. [ABSTRACT FROM AUTHOR]

A microgrid, particularly one that is islanded, is highly sensitive to the problems of voltage and frequency variations. The voltage and frequency deviations in the power system are caused due to the mismatches in its active and reactive power, leading to power quality problems. One of the significant reasons for issues in the microgrid's power quality is voltage unbalance. A microgrid might experience voltage unbalance due to the unequal load distribution among the three phases. This paper addresses issue of unbalancing in the system by coordinating positive and negative sequence (PN-sequence) controllers of inverter-interfaced distributed generations (DGs) in an islanded microgrid. Although, particularly in islanded microgrids, independent control of distributed generations for mitigating voltage unbalance is not a feasible solution. Hence, voltage unbalance factor mitigation is achieved by implementing demand-side management through thermostatically controlled devices (TCDs) as a complementary approach to the existing sequence controllers. Moreover, this paper exhibits the coordination of the PN-sequence controller of inverter-interfaced DGs and TCDs on a standard IEEE benchmark-33 bus test system to show its benefit in maintaining the voltage unbalance factor within the standard limit of 2% as per International Electrotechnical Commission (IEC) 61000-3-13 norms in any extensive system. The performance of the proposed control strategy has been analyzed and validated considering different unbalanced loading conditions, which are time-varying as well as involving TCDs. The testing of the islanded microgrid involving coordinated control strategy along with small signal stability analysis has been executed on the MATLAB/Simulink platform. [ABSTRACT FROM AUTHOR]

The uncertainty of solar generation is a challenging issue for the operation and control of distribution systems. Also, because of the large number of control and operation variables in advanced distribution networks, the centralized optimization technique requires high computational capabilities. In this paper, a distributed voltage regulation approach in a distribution system based on the predictor corrector proximal multiplier (PCPM) algorithm has been presented. This paper focuses on the voltage rise in distribution systems with high penetration of photovoltaics. The proposed method uses a clustering approach to divide the network into partitions based on the coupling degrees among different nodes. The optimal reactive power control strategy is conducted in each partition and integrated using PCPM. The proposed method is tested on 69 and 123 nodes IEEE distribution test systems. The results confirmed that the proposed method achieves the optimal solution with the same accuracy as the centralized method but in a much shorter computation time. [ABSTRACT FROM AUTHOR]

This paper exhibits the coordinated control of 30 kVAr Distribution STATic synchronous COMpensator (DSTATCOM) with 125 kVAr Switchable Capacitor Banks for compensation of reactive power in a 750 kVA secondary radial distribution system. With the control of reactive power in a radial distribution system, the power factor can be improved near to unity. The selected radial distribution system mainly feeding power to vital loads of an Educational Institution. In this paper, the study of 750 kVA secondary radial distribution system is analyzed in terms of electrical power system of institute, power consumption pattern and tariff related issues. Some conclusions to improve the system performance in terms of power factor and reduction in tariff were drawn. The coordinated control of switchable capacitor bank and DSTATCOM performance depends on the calculation of the reference source currents that generates the gating pulses of the voltage source converter-based DSTATCOM. For this purpose, the control strategy adopted is Real and Reactive power (PQ) control, Synchronous Reference Frame theory, Back Propagation Control algorithm and Adaptive Linear (ADALINE) control is implemented in this system using MATLAB/SIMULINK software. Generation of the PWM pulses triggers the IGBT of the VSI-based DSTATCOM. This is achieved using DSP TMS 320 F 2812, a 32-bit processor that is programmed with CCS V3.3 and C2000 embedded code generation tool using MATLAB/Simulink, and the same is being executed with code composer studio V 6.0.1. The performance of the selected secondary radial distribution system is analyzed experimentally in a hardware prototype to evaluate the effect of DSTATCOM and switchable capacitor bank. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal reactive power control method to maximize wind farm revenue and minimize the total electrical losses of a doubly-fed induction generator (DFIG)-based wind farm. Specifically, the split Bregman method is used to solve the optimal control problem in a distributed manner. That is, the optimization problem is decomposed into sub-problems by the optimal distributed control strategy, and each sub-problem is solved independently in each local controller through the parallel method, which reduces the calculating burden and improves the information privacy. Thus, when a fault occurs, the proposed distributed control strategy can overcome the system fault and improve the reliability and security of the system. Furthermore, an economic financial model of annual revenue is contributed to examine the income impact with or without certified emission reduction (CER) by the clean development mechanism (CDM). Compared with the dual ascent (DA) method, sequential quadratic programming (SQP) method and the proportional dispatch method (PDM), the annual revenue (AR) of the wind farm using the proposed split Bregman method is the highest. Simulation results demonstrate that this method has promising performance in both optimization quality and computational efficiency. [ABSTRACT FROM AUTHOR]

Aiming at the complex structure, numerous equipment, intricate control and protection logic, as well as the existence of numerous unmodeled dynamics and black-box device models in photovoltaic (PV) grid-connected systems, a modeling method based on Particle Swarm Optimization Neural Network (PSO-NN) is proposed to address the inability of pure mechanism models to accurately simulate their operational dynamics. Utilizing the differences in active power response waveforms under Voltage-Frequency (Vf) control, Power-Reactive Power (PQ) control, and Droop control as criteria for control strategy identification, a PSO-NN model is constructed for PV grid-connected systems, with inputs comprising temperature, humidity, light intensity, voltage, and frequency disturbances, and outputs being active and reactive power. To validate the model's effectiveness, a PV grid-connected system model is built in a self-developed simulation software and connected to an IEEE 14-bus distribution network for simulation verification. The results demonstrate that the proposed PV grid-connected model can effectively identify the types of Vf control, PQ control, and Droop control strategies, and accurately reflect the dynamic response characteristics of active and reactive power under various voltage and frequency disturbances. [ABSTRACT FROM AUTHOR]

This paper introduces one-cycle control (OCC) for reduced-DC-voltage-fed three-leg converter for single-phase active filtering and reactive compensation. The proposed power circuit configuration uses six switches (and associated gate drive circuits) and provides a better performance compared to eight-switch version (four-leg) in terms of reduced component count. It has lower semiconductor loss and lower high-frequency distortion in the grid current compared to four-switch version (two-leg). The proposed closed-loop control exhibits grid voltage sensor-less operation with effective compensation of nonlinear/reactive loads (IEEE 519-2022 compatible) and resonance damping of the filter network within the converter. Moreover, the reactive power drawn by the capacitor causes a slight deviation in the reactive power operation. An additional compensation term along with resonance damping term is incorporated in the OCC to overcome this problem. A detailed comparison of semiconductor losses among two-leg, three-leg, four-leg configurations is carried out using PLECS software. The proposed concept is verified through simulation studies. [ABSTRACT FROM AUTHOR]

The electrical power system (EPS) has been heavily stressed due to high load demand. It operates close to the total capacity limits, resulting in voltage instability that can lead to voltage collapse. In this regard, incorporating flexible alternating current transmission system (FACTS) devices and renewable energy sources (RESs) to obtain the optimum values of the generator voltage, reactive compensation, and transformer tab in optimal reactive power dispatch (ORPD) is essential in increasing the reliability and safety of the system. ORPD involves discrete and continuous variables, which are nonlinear, noncontinuous, non-convex, and complex problems. The objective functions of ORPD are reduction in active power loss (Ploss), voltage deviation, and voltage profile enhancement. This paper presents a recent advancement of the ORPD problem, mathematical formulation of the objectives function, and a summary of various metaheuristic optimization methods (single and hybrid) used to solve the ORPD problems. The hybrid method combines two or more methods to improve the demerits of one method to obtain a quality solution to a problem. This review covered incorporating FACTS devices and RESs used in solving the ORPD problem to reduce the active Ploss and improve the voltage profile in the EPS. The benefits of FACTS devices and RESs are also discussed. Also, various metaheuristic algorithms (single, modified, and hybrid) employed to solve the ORPD problem were discussed. The future direction for researchers in this field was provided to give insight into the applicability and performance. Overall, this research explores different techniques used in solving ORPD problems from the optimization point of view to incorporating RESs and FACTS devices to obtain quality solutions. Some existing methods do not guarantee an optimum solution, but incorporating RESs and FACTS devices will help attain the best solution to the problem for better power system operation to improve system reliability and voltage profile. Based on the review journal, it can be concluded that hybrid techniques offer efficient quality solutions to the ORPD problem. [ABSTRACT FROM AUTHOR]

This paper presents a grid connected solar photovoltaic (PV)-battery system using a double stage topology. The ESOGI (Enhanced Second Order Generalised Integrator)-based control estimates the positive sequence components (PSCs) of grid voltages, the amplitude of grid voltages, and unit templates. The VSC (voltage source converter) converts the DC power to AC power and providing constant power to the grid under a predefined power mode. VSC also performs multiple functions like balancing the grid currents, harmonics elimination, and providing reactive power compensation to the loads. Moreover, BDC (bidirectional converter) control maintains the voltage at the DC link and battery current. At low insolation levels, the battery supplies the required power to the load under a predefined power mode. Moreover, the battery supplies the predefined power to the grid under a predefined power mode condition. Under various dynamic conditions, simulated results and experimental results have shown a good performance. [ABSTRACT FROM AUTHOR]

Optimal reactive power flow (ORPF) is of great importance for the electrical reliability and economic operation of modern power systems. The integration of distributed generations (DGs) and two-terminal high voltage direct current (HVDC) systems into electrical networks has further complicated the ORPF problem. Due to the high computational complexity of the ORPF problem, a powerful and robust optimization algorithm is required to solve it. This paper proposes a powerful metaheuristic algorithm namely fitness-distance balance-based adaptive gaining-sharing knowledge (FDBAGSK). In the performance evaluation, 39 IEEE CEC benchmark functions are used to compare FDBAGSK with the original AGSK algorithm. Moreover, the proposed algorithm is applied to perform the ORPF task in modified IEEE 30- and IEEE 57-bus test systems. The effectiveness of the FDBAGSK method was tested for the optimization of three non-convex objectives: active power loss, voltage deviation and voltage stability index. The ORPF results obtained from the FDBAGSK algorithm are compared with other optimization algorithms in the literature. Given that all results are together, it has been observed that FDBAGSK is an effective method that can be used in solving global optimization and constrained real-world engineering problems. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method for reference current generation based on Power Oscillation Damping for the reliable operation and control of Doubly Fed Induction Generator (DFIG) under distorted grid voltage conditions. The dominant harmonic components in grid voltage such as 5th and 7th harmonic voltages lead to braking and forward torques thus causing speed oscillations and mechanical vibrations. Further, the stator active and reactive power have oscillations at 200 Hz, 300 Hz, 400 Hz and 600 Hz leading to unreliable operation of the DFIG and a possible instability of the grid. In this study, an improved method of generating the modified current references to eliminate the undesirable effect of fifth and seventh harmonics apart from the unbalance in grid voltage on DFIG performance. Here, the RSC is equipped to minimize the harmonic contents in electromagnetic torque and stator active and reactive power through a single target of damping the power oscillations, by forcing the pulsating terms of reactive and active powers to zero while maintaining decoupled steady state power flow control. The GSC focuses on mitigating the DC link voltage fluctuations while facilitating a unity power factor operation at the grid. The new reference currents for RSC and GSC are obtained by adding the fifth and seventh harmonic compensating currents to the steady state current references to meet the target. The proposed scheme is validated using PSCAD/EMTDC simulations on a 3 hp DFIG. [ABSTRACT FROM AUTHOR]

Model predictive direct power control (MPDPC) strategy offers numerous benefits over the traditional control strategies in active power filters (APF). However, the real-time execution duration (RTED) reduction of model predictive control in multilevel inverters is a big challenge. In this paper, an improved low-computation model predictive direct power control strategy for three-level four-leg APF (TL-FL-APF) is presented. First, based on generalized instantaneous reactive power theory, a new predictive power model for TL-FL-APF is established. Then, in order to reduce the RTED, classical multiple power predictions are converted into single voltage prediction through the principle of deadbeat control, and the optimized vector range is reduced from 81 to 4–18 by the method of spatial stratification using the γ-component of reference voltage vector. Finally, the simulation and experimental results demonstrate that the proposed low-computation MPDPC has excellent performance. [ABSTRACT FROM AUTHOR]

This paper presents an application for the control of a voltage source converter (VSC) through the synchronverter approach. The objective is to show that such an approach is pertinent to handle this type of converters, especially important nowadays that such devices are practically permeating small as well as large electrical networks. The paper helps to demonstrate that the proposed control strategy is capable of satisfying the requirement that a modern VSC must contribute to the Volts/Var regulation problem in the smart grid, which represents a significant challenge. The application is carried out in the context of the hardware-in-the-loop using Matlab/Simulink. The results state the VSC performance under different operating conditions and become quite relevant. [ABSTRACT FROM AUTHOR]

In today's context of power generation from wind, the demand for reliable and high-performing inverters is on the rise. The quasi-Z-source inverters (q-ZSI) are gaining attention in grid-tied wind power generation systems (WPGS) when compared to conventional inverters for their inherent capability of single-stage power conversion and maximum power point tracking (MPPT) performance. However, the erratic nature of wind speed creates a constant challenge for engineers seeking to optimize the performance of wind turbines (WT). Therefore, this paper suggests a new grey wolf-optimized MPPT (GWO-MPPT) controller for q-ZSI-based grid-tied WPGS, which holds great potential for maximizing the power output of WTs. The conventional MPPT controller used in q-ZSI-based WPGS cannot guarantee stable operation during large variations in wind speed. The GWO-MPPT controller can immediately respond during wind speed variations and trace the maximum power point (MPP) without fluctuations around it, thus improving the MPPT performance. The GWO algorithm estimates the optimum rectifier DC voltage for each wind speed to locate the MPP and subsequently determines the shoot-through duty ratio for the q-ZSI. In addition, this work introduces a decoupling current control strategy supported by dual frequency modulation (DFM) for managing the grid's active and reactive power flows. The functionality of the proposed controllers is rigorously examined using the MATLAB/Simulink tool through extensive simulations. Finally, their practicality is evaluated through an experimental hardware setup. This integrated approach thoroughly investigates the controllers' effectiveness and suitability for practical implementation in WPGS. [ABSTRACT FROM AUTHOR]

Voltage instability in power systems arises due to the shortage of reactive power and may cause abnormally low bus voltages leading to a partial or complete blackout. In order to maintain the system voltages within a safe limit, voltage control techniques such as shunt capacitor banks, Static VAR Compensators (SVCs), load shedding, and transformer tap-changer blocking, are employed. In this paper, a novel receding-horizon Model Predictive Control (MPC)-based voltage controller is proposed, which, by optimally controlling generator reactive power and SVC output, maintains the voltage stability of a power system. For this, a sensitivity-based analysis is performed to design a state-space model of the power system. The frequency and voltage dependency of load and generation are considered in the system equations. The voltage control is done step-wise, and the optimal control action in each step is calculated by minimizing a cost function subject to a set of relevant constraints. Different Voltage Stability Indices (VSIs) are used as a measure of voltage stability and also used in the constraints for the optimization problem. The performance of the proposed controller is evaluated on IEEE 9-, 39- and 118-bus systems, considering different types of loads and contingencies. [ABSTRACT FROM AUTHOR]

The optimal operation of energy resources in smart distribution system (SDS) is one of the significant concerns that must be properly addressed and is of utmost importance. By optimal operation the operating point of distributed energy resources (DERs) and the strategy of energy exchange with the upstream network can be appropriately determined. Therefore, this work aims to investigate energy loss-constrained optimal operation of SDS. The SDS comprises of dispatchable distributed generations (DDGs), solar generation and electric vehicles (EVs). Participation of DDGs and EVs in both active and reactive power is considered in this paper. The proposed operation of SDS aims at minimizing the total operating cost of SDS. Moreover, to improve the technical efficiency of SDS, energy loss is added as one of the constraints in the optimization problem. The operational problem of SDS with reactive power support from EVs is modeled as a mixed integer second-order cone programming problem and solved using MOSEK solver. Different case studies are framed and compared to investigate the effect of considering energy loss constraint and reactive power from EVs. Simulation results verify the efficacy of proposed model in optimally coordinating different DERs in SDS. [ABSTRACT FROM AUTHOR]

This paper presents a QV-based approach called Critical Voltage-Reactive Power Ratio (CVQR) index to assess the voltage instability tendencies of power system buses with increase in renewable energy (RE) penetration within the power system. The buses are thus ranked according to the order in which they are impacted by increase in renewable energy penetration. Simulations were performed using DIgSILENT PowerFactory and result analyses were done with MATLAB. The developed CVQR index has been employed to assess the effect of increasing RE generation on grid voltage stability. This index provides information on the voltage instability tendencies of all non-slack buses of the RE-integrated grid and the buses are ranked from the weakest to the strongest. The rankings obtained from the developed CVQR has been compared with five commonly-used indices and the result of the comparison verifies the accuracy of the proposed index. IEEE 14-bus and IEEE 39-bus New England systems have been used to evaluate the proposed CVQR index and various scenarios of RE system combinations and placements have been considered. Voltage collapse condition is indicated whenever the CVQR index associated with any bus becomes positive (CVQR > 0). This index can as well be applied to other power system networks. The overall ranking of the buses based on the CVQR index can provide insights on the most appropriate location for large inductive loads or compensating devices, which can either absorb or inject reactive power into the power system, thereby influencing the system's voltage stability. [ABSTRACT FROM AUTHOR]

In this paper, steady-state operating conditions of a doubly fed induction generator (DFIG) are computed considering losses of grid-side (GS) filter. Two different cases are studied for steady-state initialization of the DFIG-based wind turbine systems (WTS). In the first case, active power (P) and reactive power (Q) at DFIG terminals are assumed to be known. In the other case wind speed ( V w ), Q is assumed to be known. Apart from considering losses of the DFIG and GS filter, both the cases also consider the non-unity power factor operation of the grid side converter (GSC). For the first case, steady-state operating conditions are calculated by iterative method as well as by non-iterative method. For the second case, iterative method is used to calculate steady-state operating conditions. Calculation of steady-state values of other subsystems of DFIG-based WTS like drive train, controller and network is also shown. The initial values calculated are validated and compared by performing modal analysis and time-domain simulations. [ABSTRACT FROM AUTHOR]

Malfunctioning of islanding detection algorithms leads to system instability, failure of reclosing, and damage to load-side equipment. It also threatens security personnel. Therefore, islanding detection is an essential task for the proper functioning of the distribution system. In this paper, an islanding detection technique is presented for a grid-connected distributed power generation system. The proposed islanding detection technique is based on the change in superimposed positive sequence apparent power (CSPSAP). The CSPSAP-based islanding detection technique discriminates islanding and non-islanding events. The accessibility of positive sequence components makes the technique suitable for islanding detection for a wide range of active and reactive power mismatches. It works effectively in zero power mismatch conditions. The effectiveness of the proposed technique is verified for islanding events in cases of distributed generation disconnection with the inclusion of noise, various irradiances, and unbalanced load. Even the proposed technique proves its efficacy under various non-islanding events such as capacitor switching, different fault cases, and load switching. The impact of the proposed technique is also validated in cases of islanding and non-islanding under weak grid systems. The proposed islanding detection technique is fast due to the utilization of local measured parameters at the point of common coupling and does not have power quality degradation issues. Effects of the false detection zone and non-detection zone are also discussed with regard to the proposed technique. The proposed technique is also validated on the real-time platform of the OPAL-RT. MATLAB 2018a software is considered to model and simulate a microgrid. [ABSTRACT FROM AUTHOR]

The ancillary services are becoming more important due to the increasing integration of non-dispatchable and intermittent renewable energy sources. Such behavior under deregulation necessitates the procurement of these services suitably. This paper presents the multi-objective procurement of voltage control ancillary service in a dynamic pool deregulated system that is contingent to wind and solar power generation uncertainties. The shunt capacitors bid to supply this service and their switchings, although restricted due to life expectancy, depend on locational marginal prices. An improved multi-objective artificial electric field algorithm, which adopts the concept of Pareto-based non-dominated sorting, is presented to co-optimize total cost and voltage deviation. The particle's positions are updated through randomly picked Pareto solution to enhance exploitation capability. The sign and reorder mutation operations are employed to maintain diversity in the population, improve exploration, and evade local optima trap. The performance is investigated for different levels of wind and solar penetration on IEEE 30-bus and IEEE 118-bus test systems. The convergence of presented algorithm is analyzed and compared with other algorithms through statistical metrics and associated boxplots. [ABSTRACT FROM AUTHOR]

Distributed generation (DG) is integrated in a passive distribution system to reduce power loss, improve voltage profile, and increase power output. To reap the most benefits of the distribution system, the best location and appropriate DG size must be determined. This paper presents a hybrid Grey wolf Optimizer (GWO) and Particle swarm optimization (PSO) approach for determining the best placement and DG size while considering a multi-objective function that includes active and reactive power loss minimization as well as voltage profile enhancement. Dilla distribution system was used as a case study and the weighted technique was used to convert to a single objective function while taking into account multiple constraints such as bus voltage limit, DG output limit, and branch current limit. DG penetration is limited to up 60% of the total active load on the feeder and a forward–backward sweep load flow algorithm was used to generate the load flow solutions. The findings of the study show that combining three PV-DGs (Case 3) is the best way to improve voltage profile and minimize losses. In addition, the proposed hybrid GWO-PSO algorithm performed better compared to the other four algorithms (Grey Wolf Optimization (GWO), Whale Optimization Algorithm (WOA), Particle swarm optimization (PSO), and sine cosine algorithm (SCA)) in terms of achieving the best multi-objective function (MOF) outcome. [ABSTRACT FROM AUTHOR]

Reactive power supervision and regulation within the disciplined borderlines have captivated phenomenal attention for the sake of running the power system at stable and efficient potential. Energy sources furnished with advanced power and control architectures present robust and versatile features for load sharing, command-based control, reactive power compensation and power factor tuning for a wide range of loads. Photovoltaic (PV) module integrated with advanced inverter technologies has the ability to indirectly tune the reactive power from the grid with strict precision which is impossible to achieve with conventional passive compensators. This paper presents a novel method for active and/or reactive power compensation from PV-based STATCOM embedded with maximum power point tracking (MPPT) algorithm and having the capability of power injection into the grid. The modeling initiates with the implementation of phase locked loop, detection of load current components and inverter reference generation based on the command signal to control the grid current. The effect of enabling the MPPT command causes generation of maximum active power from PV module irrespective of the load demand which sinks to the grid in case of its surplus availability. Finally, the reactive power supply from the grid is indirectly controlled by implanting a phase shift equivalent to the set power factor in the PLL output which rotates both the inverter and the grid current vectors. The proposed methodology of command-based tuning of power factor is open loop by nature which eliminates instability issues, produces least steady-state error and is fast enough to converge in a reasonable time. [ABSTRACT FROM AUTHOR]

The objective of this manuscript is to develop algorithm to finding the losses and generation costs. Among the various FACTs devices, Hybrid Power Flow controller is considered in this same manuscript. This controller is giving better performance while comparing the other FACTs Controllers of the power system. Then Genetic Algorithm controller is included in this manuscript along with Hybrid Power Flow Controller for finding the Cost function and power losses in different buses. The Genetic Algorithm is usually used to generate high-quality solutions or results to optimization and search different kinds of problems. In power systems of receiving end side of a transmission limits will be improved by careful voltage profile by introducing suitable reactive power into the power system. The continuations of the multiple solutions in the optimal situation of reactive power in the power system are using Genetic Algorithm. Along with Genetic Algorithm the FACTS controllers of distribution systems are using minimization or reduction of total real power loss of the power system. The proposed methodology has been tested for IEEE-14 bus distribution test system. Finally, this paper is focused about produced voltage profile and generation cost function of with and without controller using Genetic Algorithm. [ABSTRACT FROM AUTHOR]

Voltage regulation issue in the distribution network is considered as a challenge that is associated with high penetration of the distributed generations (DGs). The widespread of the DGs led to influence the operation of the reactive power compensation (RPC) devices and the on-load tap-changers (OLTCs) and significantly affected the voltage profile. Therefore, obtaining the suitable control settings for the OLTC and the RPC should be reconsidered considering the impact of the DGs. This paper proposes a strategy for coordinating the operation of the OLTC and the RPC with DGs in the distribution networks. The proposed coordination strategy obtains the optimal values of the active power generated from the DGs, the reactive power injected from the switched capacitors (SCs), and the tap settings of the OLTC by using the multi-objective particle swarm optimization (MOPSO). The objective function is to minimize the total active power losses for all lines and the total voltage deviation for all nodes in the distribution network. The proposed coordination strategy is tested on the modified IEEE 33-node test feeder and a practical distribution feeder extracted from the North Delta Electricity Distribution Company in Egypt. A MATLAB code is built in this paper for simulation of the case studies and for determining the optimal parameters. A comprehensive comparison between the proposed MOPSO and the mixed-integer linear programming (MILP) method for different operating conditions of the distribution network is made. The results demonstrate that, the proposed strategy decreases the power losses, improves the voltage regulation and provides efficient coordination of DG with the voltage regulating devices; SCs and OLTC. [ABSTRACT FROM AUTHOR]

This paper presents the variation in current harmonics injected by the LED lamps and their effect on harmonic estimation in the low-voltage network. Lighting consumes a significant portion of total electricity consumption in residential, commercial and industrial sectors. The energy-efficient lights, for example, light-emitting diode lamps, are reducing this share significantly over the last few years. These nonlinear LED lamps are the source of current harmonics and reduce the power quality in the low-voltage grid. The estimation of the magnitude by which they affect the power quality is essential for network operators. However, the thermal stability of the lamps is a prime consideration for the accurate assessment of the power quality. This paper investigates the effect of thermal stability on current harmonics injected by LED lamps. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of a Direct Power Control (DPC) based on a virtual flux estimator and an optimal Switching Table (VF-ST-DPC) for a three-phase PWM rectifier. The proposed approach combines DPC principles, a virtual flux estimator concept, and an optimal switching table (ST) to select the optimal converter vector control. The objectives of this approach are to solve the cross-coupling between instantaneous active and reactive powers for each sector and to enhance harmonic line currents. Thus, the proposed method is carried out in a fixed coordinate frame. It therefore does not require a Park transformation or the synchronization of the grid voltage, which is achieved by a virtual flux estimation method. Experimental results, based on the dSpace DS1104 board, show that the VF-ST-DPC ensures smooth and decoupled control of instantaneous active and reactive power, as well as low harmonic levels (THD = 4.6%), verifying the expected performances of the proposed method under both steady-state and transient operations. [ABSTRACT FROM AUTHOR]

The large-scale wind power grid connection will change the power distribution between the original system tide and synchronous machine, and the interaction between wind turbine and synchronous machine affects the system's damping oscillation characteristics. Traditional synchronous generators' extra damping control provides an important means for DFIG to improve system damping characteristics. Different types of PSS have different suppression effects on low-frequency oscillations. In this paper, four types of IEEE PSS models are built in DIGSILENT/PowerFactory to study the suppression effects of DFIG additional different types of PSS on low-frequency oscillations of power systems, and the suppression effect of four types of PSS on system low-frequency oscillation after connecting to the DFIG reactive power control loop is compared and analyzed from two perspectives: eigenvalue and time-domain simulation. The MRAC control principle is used to improve PSS4B, and the total least squares-estimation of signal parameters via rotational invariance technique identification method is used to obtain the system transfer function, and the controller parameters are calculated in real time using the adaptive law based on the gradient approach. Finally, the MRAC–PSS4B is connected to the DFIG rotor-side controller's reactive power control loop, and the improvement effect of the designed MRAC–PSS4B controller on the power system's low-frequency oscillation characteristics under different contact line transmission power is confirmed. [ABSTRACT FROM AUTHOR]

The classical droop method is widely used in AC microgrid (MG) for sharing load among distributed generations. Apart from interlinking the DC sources, the voltage source inverters control the power flow from renewable energy sources. Thus, they contribute toward the demand side management (DSM) by employing the voltage reduction method (VRM). The VRM is widely utilized in the distribution system of the grid network, its concern is to reduce the voltage in a suitable manner so as to maintain the voltage within the acceptable limits, leading to power savings. However, the application of VRM in the stand-alone MG is very scarce. Thus, this paper attempts to apply VRM so as to achieve not only the benefits pertaining to voltage control but also power savings from DSM. The voltage–current (V–I) droop characteristics are of paramount importance for DSM using VRM to increase the number of consumers during high demand of electrical energy. One of the important contributions is modification of the P–f droop control to maintain the frequency of the MG within the permissible limit while applying VRM. In addition, the behavior of three-phase to ground fault is being investigated and competency of the control algorithm is validated through implementation on 5 bus stand-alone microgrid system and further, it is tested on IEEE 14 bus test system. The efficacy of the proposed approach is established through the comparison of the results with those for classical voltage and frequency-based droop schemes bereft of communication ability. The control mechanism has also been validated in real-time using schematic editor of Typhoon virtual HIL 402. [ABSTRACT FROM AUTHOR]

This paper focuses on the self-synchronization control of cascaded-type STATCOM. One module is controlled as the current source, and the rest are regulated as voltage sources. The low-bandwidth communication is just used to transmit the given reactive powers. Via the carrier of common grid current acquired locally, the self-synchronized operation of all modules is realized. When a short interruption in communication occurs, the stable operation of the system is unaffected. Thus, the system reliability is improved in case of communication failure. The small-signal stability of the proposed scheme is proven. Finally, the effectiveness of the proposed scheme is verified by both simulation and hardware-in-the-loop results. [ABSTRACT FROM AUTHOR]

The harmonics and reactive power have severe consequences on the power electronics-enabled distribution networks. Imposing a penalty to a consumer for violation of limits and providing an incentive for utility-related problems promote good practices. Therefore, we need to reframe the prevailing tariff structure to improve the power quality (PQ) of the low voltage (LV) distribution networks. Nevertheless, there is no unique standard tariff structure in practice for the PQ regulation. This paper presents a penalty/incentive-based tariff scheme for LV consumers to regulate their reactive power and harmonic injection within limits. The pricing is arrived at, considering the techno-economic aspects of excessive reactive power consumption and harmonic pollution. Unlike empirical approaches in the literature, the pricing scheme is more realistic owing to real-world factors like energy losses in the line due to reactive and harmonic current, capital investment on the capacitor bank, and active harmonic filter. The proposed penalty/incentive scheme is validated on an LV radial distribution network with diverse loading conditions. From the results, the proposed tariff scheme is found to be more comprehensive, realistic, and regulatory as it appropriately penalizes/incentivizes both single-phase and three-phase consumers according to their reactive and harmonic profile, with a time resolution suitable for capturing consumer and grid PQ phenomena. [ABSTRACT FROM AUTHOR]

Recent interest in Power Quality (PQ) enhancement and control strategies for DC/AC converters in grid-tied and islanded modes has surged. Conventional single-loop and multi-loop control topologies using PI, PR, and hysteresis controllers are widely used for system stability, current control, and PQ improvement. However, these topologies face significant challenges under non-ideal conditions, such as inverters with nonlinear or unbalanced loads. This paper addresses the challenges of simultaneous harmonic compensation and decoupled active and reactive power reference tracking by proposing a novel Hybrid SOGI-Resonant Controller (HSRC). The HSRC is designed to adapt to changing load patterns and mitigate harmonics generated by nonlinear loads. It incorporates a Second Order Generalized Integrator (SOGI) into a synchronously rotating reference frame (SRRF)-based PI-control scheme. Acting as a notch filter, the SOGI improves reference generation based on load current harmonics. The HSRC combines the benefits of Resonant controllers with cascaded PI controllers without frequent reference frame conversions. The proposed topology demonstrates significant improvement in grid-tied inverter (GTI) performance with nonlinear loads and unbalanced load combined, eliminating the need for separate controllers for positive and negative sequence signals and reducing computational burden. It provides independent control of active and reactive power alongside harmonic compensation, ensuring seamless operation under nonlinear loading conditions. The paper details the design and tuning methodology of the HSRC and verifies its efficacy through the grid-tied operation of a three-phase GTI with different loads. Results show a substantial reduction in total harmonic distortion, highlighting the HSRC's potential for enhancing power quality in practical applications. [ABSTRACT FROM AUTHOR]

In the context of a deregulated electricity market, this paper presents a new method for the distribution of electrical losses in distribution systems with local generators, incorporating variations in consumer power factor. Additionally, the paper examines how local generators may gain the utmost possible advantage from their contributions to system performance enhancement. The proposed approach initially analyzes dynamic changes in active and reactive power flow caused by a change in consumer power factor, followed by a loss allocation mechanism. This method is developed based on Kirchhoff’s law and the natural decomposition of injected bundled power flow at a bus. To completely eliminate cross-subsidies, the proposed mechanism follows a two-stage power flow: first, consumer-controlled power flows, and second, determining variations in power flow as compared to the first stage due to interactions with local generators. Consumer load modeling is being considered to improve the proposed method’s adaptability and efficiency across different distribution systems. The effectiveness of the proposed method is validated through testing on 30-bus and 69-bus distribution systems, and the results obtained are compared with those of other methods found in the literature. [ABSTRACT FROM AUTHOR]

A design procedure for an RLC damping branch applied at a voltage source inverter followed by an LCL output filter is carried out in this paper. The main purpose of the proposed methodology is to allow the system to operate properly in both grid-connected (GC) and islanded (IS) modes with smooth transitions between them. The usage of passive damping methods to smooth the resonating filters effects is well known. However, the design procedure of the damping branch is specific for either the GC or IS mode, and usually, the parameters tuned for an operation mode are unsuitable for the other one. Thereby, this paper contributes to presenting a methodology design of an RLC branch aimed to achieve damping effect for both operation modes, thus allowing the continuous operation with no hazardous transients during transitions. By means of the proposed approach, the passive elements are adequately designed in order to provide easy controller synthesis. Therefore, a two-loop control strategy is adopted where the inner loop controls the capacitor voltage and ensures the system stability for both operation modes; meanwhile, an additional outer loop controls the grid current for GC mode allowing active and reactive power flows. Experimental results for a 2-kW prototype are presented in order to validate the proposed design methodology and control strategy. [ABSTRACT FROM AUTHOR]