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There have been a large number of important discoveries in the field of experimental high energy physics over the past fifty years. Some of the important milestones are (1) discovery of the neutral current to establish the first step of the electroweak theory; (2) evidence of charm and beauty through the search of quarkonia and multi-muon events in deep inelastic scattering; (3) discovery of the third generation through the discovery of the tau lepton; (4) evidence of Bjorken scale breaking to initiate Quantum Chromodynamics, the theory of strong interaction; (5) observation of parton (quark) showers in the formation of jets and discovery of gluons; (6) discovery of the W and Z bosons, the mediators of the weak interaction; (7) precision measurements of the properties of the W and the Z bosons to establish the correctness of radiative corrections and to predict of yet to be discovered particles like the top quark and the Higgs boson; (8) discovery of the top quark and the tau neutrino; (9) establishing neutrino oscillation and thereby massive neutrinos; (10) finding CP violation in the decays of hadrons from the third generation of quarks; (11) discovery of the Higgs boson. During this process, the field of experimental high energy physics also experienced revolutions in the detection techniques, triggering and data acquisition systems and finally the use of new analysis techniques like detector simulation and artificial intelligence. Some of these important discoveries will be outlined in this paper. [ABSTRACT FROM AUTHOR]

During the operation of the urban subway, there will be stray current leaking into the ground, which may invade the neutral point of the transformer along the subway line, causing the working magnetization curve of the transformer core to shift, thereby causing the direct-current (DC) bias effect of the transformer. Since there are unknown parameters in the equivalent circuit model of the stray current of the subway, in order to simplify the process of the influence of the subway operation on the neutral current, based on the analysis of the formation mechanism of stray current, a real subway line has been selected and a monitoring platform in the nearby high-voltage (HV) substation has been built to record the neutral current. Meanwhile, through the on-site recording of the entry and exit time of subway trains at four consecutive stations, the running trajectories of the subway trains can be reversed. According to the trajectory of the subway train, the recorded neutral current was re-divided into time periods, and the synergistic analysis of the neutral current and the train trajectory in the corresponding time period was carried out. The neutral current measurement results for 4 consecutive days indicate that the influence of the subway train on the neutral current of the substation is mainly the influence of the unbalanced load, and the degree of the unbalance mainly comes from the distance and the acceleration and braking of the subway train. The trajectory of the subway train is related to the amplitude of the neutral current. The closer the subway train is to the substation, the greater the impact on the neutral current.

This suggested research work provided a distributed generator-based unified power quality conditioner with a decreased rating and a star-connected transformer as a means of enhancing power quality. The unified power quality conditioner (UPQC), a Y-connected transformer, and an LC filter are all included in this work. When the source voltage is out of balance, the hybrids of the approach greatly enhance UPQC performance. The quality conditioner that is suggested here is intended to correct issues with the voltage and current quality of delicate loads and to reduce load current harmonics when the supply is distorted. In this case, the DC link control method has been implemented using a fuzzy logic-based controller. A 500 kVA grid model is taken into consideration, along with an analysis and description of the suggested solution. The results were produced using the power system block set toolboxes in the MATLAB/Simulink environment. According to the thorough simulation results, hybrid UPQC with distributed generation has a greater ability to reduce the voltage sag effects and swell and to suppress the load current harmonics, phase current harmonics, and neutral current when the supply is distorted. To validate the results generated by the proposed method, the hybrid methodology yields better results when compared to the traditional UPQC method. [ABSTRACT FROM AUTHOR]

The fast deployment of distributed energy resources (DERs) is creating a series of challenges that should be addressed in the coming years. In particular, distribution grids are playing an increasingly important role in the electricity system. Moreover, the three-phase four-wire structure of this network contribute to the appearance of imbalances and a series of problems derived from them. In this context, distribution system operators (DSOs), as the main responsible for the distribution grid, must ensure the quality of supply to consumers. This paper takes advantage of a four-legs D-STATCOM to remove current imbalances in low-voltage power lines. A 35-kVA prototype has been developed and installed in an urban distribution grid. The effect of the D-STATCOM has been analyzed during its first month of operation, studying and measuring the advantages of providing DERs the ability to perform active balancing to the utility grid. The results show a reduction in current imbalances from 21 % to 0 % and neutral current from 10.3 A to 0.4 A. In addition, a 13 % decrease in cable losses has been estimated and a slight improvement in voltage unbalance factor can be noted.

The operation of devices with different load types is related to the occurrence of distortions such as high current and voltage harmonics, phase and power imbalance. Electrical equipment may not operate correctly due to higher harmonics and power and phase imbalance. Neutral current is the result of harmonics and power and phase imbalance. In three-phase systems, current may flow in the neutral conductor due to the imbalance problem caused by the loads or the wrong wiring. Non-linear loads inject harmonic currents into the grid or source. When triple harmonics are present in the network, the neutral current is not zero even if the load is perfectly balanced. This can increase the risk of fire due to overheating of the neutral conductor due to overload. In this study, power parameters were measured by performing five measurements in three phases (Phase A, Phase B and Phase C) in three different facilities. The effects of load unbalance and triple harmonic values on neutral current are compared. Although the power imbalance standard error value in the first and second measurement was close to each other, there was approximately 30% variation between the triple harmonic values, while the difference in neutral current was 13.27 A. For the test system in the current study, it was concluded that triplen harmonics have more effect on the current in the neutral conductor than unbalanced loading. [ABSTRACT FROM AUTHOR]

Distributed energy sources including renewable energy (RE) sources and electric vehicle (EV) discharging offer opportunities to improve grid performance. Although uncoordinated EV charging can perfectly meet users’ driving needs, it brings great challenges in maintaining the quality of low voltage (LV) distribution grids. Most existing EV control strategies do not take into account the heterogeneous nature of EV charging, including the various users’ travel needs and the intermittent nature of RE sources. This article proposes a hierarchical control method that simultaneously coordinates EV charging by considering a dynamic energy tariff, RE sources, EV hardware characteristics, and particularly the EV’s driving needs. The proposed local controller sends the EV’s charging priority and required energy to the central controller based on the EV’s hardware characteristics and users’ driving needs. The central controller then uses this information along with the energy tariff from the retailer and the present grid performance to control EV’s charging or discharging power. The efficacy of this hierarchical control method is evaluated using an Australian LV grid. The obtained results show that this method can reduce the neutral current and voltage imbalance with the maximized usage of renewable energy resources while the EV users’ driving needs are met. [ABSTRACT FROM AUTHOR]

This manuscript proposes an Internet of Things (IoT) platform for energy management (EM) in multi‐microgrid (MMG) system to enhance the power quality with hybrid method. The proposed method is the consolidation of opposition based crow search optimizer (OCSO) and radial basis functional neural network (RBFNN), hence it called RBFNOCS technique. The main aim of this manuscript is to optimally managing the power and resources of distribution system (DS) by constantly track the data from IoT‐based communication framework. In the proposed work, every devices of home is interfaced with data acquisition module (DAM) that is IoT object along unique IP address resultant in large mesh wireless network. Here, the IoT‐based communication framework is used for facilitating the development of a demand response (DR) energy management system (EMS) for distribution system. The transmitted data is processed by RBFNOCS technique. By utilizing the RBFNOCS method, the active with reactive power processing for optimal capacity unbalance compensation smart VSIs share the obtainable neutral current (NC). Likewise, the DS IoT framework enhances these networks flexibility and gives feasible use of obtainable resources. Moreover, the RBFNOCS method is responsible for satisfying the total supply with energy demand. The proposed model is activated in MATLAB/Simulink site and the performance is compared with existing models, namely improved artificial bee colony, squirrel search algorithm and gravitational search algorithm based artificial neural network (SOGSNN), GOAPSNN, fruit fly optimization, and FORDF technique. When compared with the existing methods, the efficiency of the RBFNOCS method is 93.4501%. [ABSTRACT FROM AUTHOR]

Earth current generated by the operation of urban rail transit can enter into the neutral point of grounding transformer, which will result in the deterioration of transformer operation performance and cause electrical safety problems. In this article, the neutral current for 220 kV transformers has been measured in the real power system, the characteristics of dc and harmonic current are analyzed, and a novel suppression method for the dc and harmonic current simultaneously combining an active converter with a dc blocking capacitor is proposed, which solves not only the traditional dc bias problem but also the intrusion of the harmonic current from urban rail transit. The active converter is designed to compensate harmonic voltage to suppress harmonic current, and the capacitor provides blocking for the dc current. The protection scheme in case of the high fault current of the neutral point is presented. The improved control method is designed to control the neutral current and adjust the fundamental impedance for the requirements of relay protection. The effectiveness of the proposed method is verified by the digital simulations and the laboratory experiments based on the field working conditions, and the results demonstrate the satisfying performances. [ABSTRACT FROM AUTHOR]

The existence of a new interaction involving the electron neutrino and the nucleons, which has received a convincing confirmation through a good agreement between the theoretical and experimental results concerning all observable processes with solar neutrinos, should also inevitably manifest itself in the deuteron disintegration by the neutral currents of reactor antineutrinos. The special attention is drawn to the problem of finding the neutron registration efficiency, discussed in the preparation of the experiment at the Sudbury Neutrino Observatory and in a number of special studies. Lessons are noted that can be learned from three long-standing experiments on the deuteron disintegration by reactor neutrinos. [ABSTRACT FROM AUTHOR]

The energy consumption profile continues to grow in the world. On the other hand, concern about greenhouse gas emissions and other environmental factors has made renewable energy sources more attractive to meet this new power demand. Another aggravating factor generated by the demand increase is the distribution transformer load unbalance, causing high neutral current and efficiency loss in the system. The authors propose a simple method when compared to other methods such as automatic balancing transformers and passive filters to increase system's power quality. The proposed method takes advantage of the growing insertion of solar panels in the system and consists of a smart allocation of single-phase photovoltaic panels to reduce unbalance between phases. The method is tested in a real case system within 24 h on a typical summer day and the results show that the proposed method can bring a qualitative reduction in comparison to the conventional solar panel random allocation. [ABSTRACT FROM AUTHOR]

To maximize renewable energy usage to combat climate change, the penetration of electric vehicles (EVs) has increased significantly in developed countries. This can cause serious power quality issues, such as increased voltage imbalance and neutral currents, which severely impact the operation of power systems. Although the power quality issue is not a new problem, it requires an improved strategy for the growing penetration of photovoltaic solar energy and EVs in low-voltage distribution grids and their uncoordinated operation. This article presents a new control strategy to reduce the number of coordinated EVs to mitigate voltage unbalance and compensate for the neutral current. The proposed control strategy consists of two controllers arranged in a hierarchical structure with the central controller at the top layer and the local controller at the bottom layer. It is evident that the proposed control strategy reduces the number of EVs that need to be coordinated, and further, EV coordination is not required if the grid imbalance is less. This new hierarchical control strategy can improve power quality and reduce data processing overhead and computational complexity. [ABSTRACT FROM AUTHOR]

The electronically interfaced photovoltaic (PV) system and its control approach form an intrinsic part of the distributed generation (DG) system. This study proposes pseudo affine projection (PAP)‐assisted multitasking control scheme for grid‐integrated DG inverter under input grid voltage disturbances. The PAP approach is based on the convergence of active weighted values and is independent of the input signal property, which manifests a discrete characteristic. Additionally, it exhibits a unique capability of updating weight based on multiple, delayed input signal vectors. The fundamental distinguishing feature of the proposed PAP is its intrinsic learning behaviour and therefore it provides an optimal solution to the ingrained paradox between steady‐state misadjustment and convergence speed compared to its conventional counterpart affine projection. The PAP‐assisted algorithm practically enables DG inverter to perform multiple tasks including suppression of source current harmonics, unbalancing, and neutral current. It also provides load reactive current support with unity power factor operation while transferring the maximum active power into the utility grid. The practicality of the proposed PAP algorithm is investigated through MATLAB/Simulink software. Finally, the experimental results recorded with the dSPACE‐1104 based real‐time control platform show good to excellent agreement with simulations in the steady‐state, as well as transient phenomena. [ABSTRACT FROM AUTHOR]

• An original control strategy for mitigating neutral currents using smart loads. • A simple and low complexity, model-based, dual-loop control design. • Systematic and intuitive synthesis of control gains solving LMI constraints. • Effective mitigation of neutral currents under both linear and nonlinear loads. This article presents a strategy for minimizing neutral current in distribution microgrids using electric spring-based smart loads. A dual loop control scheme is proposed – the outer loop generates reference voltages for the individual electric spring in each phase using a simple voltage division concept that results in zero neutral current, while in the inner loop, the output voltage and current of the electric spring are controlled using repetitive controllers. The control system features a simple structure and systematic design and is minimally reliant on exact knowledge of parameters, making it robust in the presence of uncertainties. The electric spring in each phase is controlled independently and identical to the other phases without requiring any axis transformation. Detailed design of the proposed solution is presented and its performance is tested by simulating it on a benchmark low-voltage distribution microgrid to show its effectiveness and validity. [ABSTRACT FROM AUTHOR]

In this paper, a novel technique to improve the fault detection sensitivity in a three-phase transformer using the tank current method is reported. The tank current method was first published by the first author in recent past for single isolated transformer winding. A fault in single isolated transformer winding was uniquely identified employing the typical resonance behavior of tank current, but for three-phase transformer, such implementation is yet to be explored. The present scope of this paper is only for uniformly wound three-phase transformer windings. Implementing the tank current method for such a three-phase transformer may not be very simple, since the neighboring windings, unlike in the case of isolated winding, strongly influence the measurement of the tank current. Therefore, this paper appropriately considers the effect of neighboring windings in a three-phase transformer and investigates the resonance behavior of its tank current to propose a promising innovative extension approach of the method. Experimental results on actual transformers are also presented for practical validation of the proposed method. Results imply that the tank current method is indeed very sensitive to identify the fault in an actual transformer compared to the conventional neutral current method. The authors also believe that the method needs to be reinforced by field measurements on several transformers to ascertain its viability. [ABSTRACT FROM AUTHOR]

The smart transformer (ST), with its high control capability, offers new features for optimizing the management of the distribution grid. The ST, by controlling the voltage in each phase independently, is able to manage the operations during grid faults, in particular in the single-phase ones. The ST, when a single-phase-to-ground fault occurs, can rapidly reduce the voltage in the phase under fault. Thus, it guarantees system safety and operates with the remaining two healthy phases to avoid unnecessary interruption in the healthy lines. However, the two-phase asymmetrical operation challenges the system performances due to the high power 2nd harmonic ripple in the dc voltage, that reduces the capacitors, lifespan and the high current flowing in the neutral conductor. These issues would force the grid operator to increase the ST maintenance, in order to avoid unplanned faults in the ST hardware, due to failure of aged capacitors. This paper presents a flexible-control strategy, based on the phase-shift angle control between two healthy-phase voltages, that reduces the impact of the power 2nd harmonic oscillation and thus can delay the maintenance intervention. The proposed strategy aims to improve system performances by avoiding neutral-line current overload and attenuating ac side active power (low voltage dc-link voltage) oscillation. Depending on the grid conditions (small dc link capacitance or low ampacity of neutral cable), the voltage angle can be adapted, minimizing the impact of the two-phase operation system in the ST-fed grid. The effectiveness and feasibility of the proposed approach have been validated experimentally with a simplified microgrid setup. [ABSTRACT FROM AUTHOR]

The presence of a neutral current is quite common in three-phase (3P) four-wire (4W) distribution systems due to an unequal distribution of linear and nonlinear single-phase (1P) loads and small distributed generators. However, a high neutral current can overload the neutral conductor and distribution transformer, which can cause electrical safety concerns and even fire. Among several existing neutral current compensators, the 3P four-leg (4L) voltage-source inverter (VSI) provides better control flexibility and more efficient performance than the passive compensators but requires a higher VSI capacity for the fourth-leg operation. To provide a solution to the aforementioned problem, this paper presents a novel control method to utilize the available capacity of a 3P-4L VSI after active and reactive power regulation to enhance the neutral-current compensation. A smart VSI (SVSI) is designed to operate with a solar photovoltaic unit, regulate the ac side voltage, and minimize the neutral current. Case studies are conducted with actual load data from a commercial building in the PSCAD/EMTDC software environment. The designed system with the proposed control method can provide a significant improvement in the neutral-current compensation, phase balancing, and unbalance factor compared to a fixed-capacity 3P-4L SVSI. Experimental results using a TMS320F28335 digital signal processor microcontroller and modified Semiteach 3P-4L inverter are presented to verify the robustness of the designed controller and the enhancement to the neutral-current compensation using the proposed dynamic capacity-control method. [ABSTRACT FROM AUTHOR]

This paper presents some considerations regarding the application of the stator zero-sequence current component (ZSC) in the fault detection of cage induction machines, including the effects of magnetic core saturation. Faults such as rotor cage asymmetry and static, dynamic, and mixed eccentricity were considered. The research started by developing a harmonic motor model, which allowed us to obtain a voltage equation for the zero-sequence current component. The equation allowed us to extract formulas of typical frequencies for particular fault types. Next, in order to verify the effectiveness of ZSC in induction motor fault diagnosis, finite element calculations and laboratory tests were carried out for the previously mentioned faults for delta and wye connections with neutral wire stator winding configurations.

In the last decade, mainly due to political incentives towards energy efficiency, the share of lamps with power electronic interfaces, like Compact Fluorescent Lamps (CFL) and Light Emitting Diode (LED) lamps, has significantly increased in the residential sector. Their massive use might have a substantial impact on harmonic currents and, consequently, on the current flowing in the neutral conductor. This paper analyzes the impact of modern energy-efficient lighting technologies on the neutral conductor current by using a synthetic Low Voltage residential grid. Different load scenarios reflecting the transition from incandescent lamps, via CFL, to LED lamps are compared concerning the neutral conductor current at different points in the network. The inherent randomness related to the use of lighting devices by each residential customer is considered employing a Monte Carlo simulation. Obtained results show that the use of CFL has a greater impact on the neutral conductor current of Low Voltage (LV) residential grids and that, with increasing use of LED lamps, a decreasing impact can be expected in the future.

An increase in the neutral current results in a malfunction of the low energy over current (LCO) protective relay and raises the neutral-to-ground voltage in three-phase, four-wire radial distribution feeders. Thus, the key point for mitigating its effect is to keep the current under a specific level. The most common approach for reducing the neutral current caused by the inherent imbalance of distribution feeders is to rearrange the phase connection between the distribution transformers and the load tapped-off points by using the metaheuristics algorithms. However, the primary task is to obtain the effective load data for phase rearrangement; otherwise, the outcomes would not be worthy of practical application. In this paper, the effective load data can be received from the feeder terminal unit (FTU) installed along the feeder of Taipower. The net load data consisting of customers’ power consumption and the power generation of distributed energy resources (DERs) were measured and transmitted to the feeder dispatch control center (FDCC). This paper proposes a method of establishing the equivalent full-scale net load model based on FTU data format, and the long short-term memory (LSTM) was adopted for monthly load forecasting. Furthermore, the full-scale net load model was built by the monthly per hour load data. Next, the particle swarm optimization (PSO) algorithm was applied to rearrange the phase connection of the distribution transformers with the aim of minimizing the neutral current. The outcomes of this paper are helpful for the optimal setting of the limit current of the LCO relay and to avoid its malfunction. Furthermore, the proposed method can also improve the three-phase imbalance of distribution feeders, thus reducing extra power loss and increasing the operating efficiency of three-phase induction motors.

Transient overvoltages appearing at line terminal of power transformer HV windings can cause failure of winding insulation. The failure can be from winding to ground or between turns or sections of winding. In most of the cases, failure from winding to ground can be detected by changes in the wave shape of surge voltage appearing at line terminal. However, detection of insulation failure between turns may be difficult due to intricacies involved in identifications of faults. In this paper, simulation investigations carried out on a power transformer model winding for identifying faults between turns of winding has been reported. The power transformer HV winding has been represented by 8 sections, 16 sections and 24 sections. Neutral current waveform has been analyzed for same model winding represented by different number of sections. The values of α (‘α’ value is the square root of total ground capacitance to total series capacitance of winding) considered for windings are 5, 10 and 20. Standard lightning impulse voltage (1.2/50 μs wave shape) have been considered for analysis. Computer simulations have been carried out using software PSPICE version 10.0. Neutral current and frequency response analysis methods have been used for identification of faults within sections of transformer model winding.

In this work, we establish an effective medium model to describe the low-frequency complex dielectric (conductivity) dispersion of dilute clay suspensions. We use previously obtained low-frequency polarization coefficients for a charged oblate spheroidal particle immersed in an electrolyte as the building block for the Maxwell Garnett mixing formula to model the dilute clay suspension. The complex conductivity phase dispersion exhibits a near-resonance peak when the clay grains have a narrow size distribution. The peak frequency is associated with the size distribution as well as the shape of clay grains and is often referred to as the characteristic frequency. In contrast, if the size of the clay grains has a broad distribution, the phase peak is broadened and can disappear into the background of the canonical phase response of the brine. To benchmark our model, the low-frequency dispersion of the complex conductivity of dilute clay suspensions is measured using a four-point impedance measurement, which can be reliably calibrated in the frequency range between 0.1  Hz and 10 kHz. By using a minimal number of fitting parameters when reliable information is available as input for the model and carefully examining the issue of potential over-fitting, we found that our model can be used to fit the measured dispersion of the complex conductivity with reasonable parameters. The good match between the modeled and experimental complex conductivity dispersion allows us to argue that our simplified model captures the essential physics for describing the low-frequency dispersion of the complex conductivity of dilute clay suspensions. [ABSTRACT FROM AUTHOR]

Increased penetration of nonlinear loads like power electronic converter based systems have aggravated issue of harmonic injection in the power system. Neutral current harmonics is an issue of concern for three phase four wire system. This paper is focused on the elimination of neutral current harmonics with the help of shunt active power filter based on the star-delta transformer and single phase half bridge inverter. The presented active power filter eliminates harmonics present in neutral current which in turn helps in mitigating third harmonics from the supply mains. The topology has the advantage of reduced number of semiconducting devices and switching losses as compared to conventional three phase active filter. Simulation studies for the proposed active filter are presented and compared with the behavior of conventional three phase active filter. Experimental results for DSP based laboratory prototype of the proposed filter are shown to substantiate performance of system. Both simulations, as well as experimental results, demonstrate effective compensation provided by single phase half bridge inverter based active filter. [ABSTRACT FROM AUTHOR]

The unequal single-phase load distribution in three-phase (3P) four-wire (4W) low-voltage (LV) networks can cause significant neutral current and neutral to ground voltage rise problems at both customer and distribution transformer terminals. High neutral current can overload the neutral conductors and can cause electrical safety concerns to the users. To mitigate the high neutral current problem in an unbalanced residential LV network, a multifunctional 3P four-leg (4L) rooftop photovoltaic (PV) smart voltage source inverter (SVSI) is designed with improved active neutral current compensation along with active power export and point of common coupling (PCC) voltage regulation. A novel dynamic capacity distribution (DCD) method is proposed using the available SVSI capacity after active and reactive power operations to achieve higher capacity neutral compensation at the PCC. The performance of the designed 3P-4L PV-SVSI with the DCD method is compared with a traditional 4L SVSI with fixed unbalanced compensation capacity and a passive unbalance compensator, such as a zig-zag transformer, in PSCAD/EMTDC software. Several case studies, such as balanced and unbalanced load changing effects, are presented with actual residential loads connected to an Australian 3P-4W LV network. A Semikron Semiteach modified inverter and a real-time TMSF28335 DSP microcontroller are also used to provide experimental verification on the improvement of the proposed neutral current compensation with the DCD method. Detailed simulations and experimental studies are presented to verify the robustness and efficacy of the proposed control strategy with the designed 3P-4L PV-SVSI. [ABSTRACT FROM AUTHOR]

This study proposes a single‐stage solar photovoltaic energy conversion system (PV‐ECS) integrated to a three‐phase four‐wire (3P4W) distribution grid with dual‐function capabilities, i.e. active power transfer and power quality (PQ) enhancement at the point of interaction (PoI). The PV‐ECS system comprises of a solar photovoltaic array and a voltage source inverter (VSI), supplying active power (during daytime) to the distribution grid and connected single‐phase and three‐phase loads. Apart from transfer of power, the system also improves the PQ at the PoI by compensating reactive power and neutral current, attenuating harmonics, correcting power factor and balancing grid currents. During night, the VSI acts as a shunt active power filter mitigating PQ issues, thereby increasing the device utilisation factor. A three‐phase magnitude‐phase locked loop (3M‐PLL) method is utilised to extract and estimate fundamental term of load currents and an incremental conductance algorithm is applied for maximum power point tracking. To demonstrate its effectiveness, the system is modelled and its performance is simulated on MATLAB and experiments are performed on a developed prototype in the laboratory. [ABSTRACT FROM AUTHOR]

This study presents the fuzzy logic integrator gain‐tuned improved second‐order generalized integrator (GI) for a double‐stage grid‐interfaced photovoltaic (PV) system. The proposed system includes the functionalities of feeding active power to the grid, power factor correction, grid currents balancing and system isolation under grid side faults. Moreover, the smooth system operation is ensured under weak distribution grids where grid voltage is subject to huge diversions. Furthermore, automatic protection scheme for the system under grid‐side faults is also established with the proposed algorithm for increased reliability. The fuzzy‐tuned GI provides advantages of efficient and effective extraction of load current fundamental component under steady‐state and dynamic grid conditions. The non‐linear frequency error variation is compensated here using fuzzy logic‐based self‐tuning integrator gain of the controller. The controller is improved to mitigate the possible DC component in the load current. The neutral current in the loads is nullified by using a four wire system. The adaptive DC bus voltage helps to minimize the switching losses and prevents unexpected tripping of the PV inverter. The system is experimentally verified using a prototype built in the laboratory. [ABSTRACT FROM AUTHOR]

Phase unbalancing is a problem in distribution networks that causes feeder service tripping and reduces the network quality. Re-phasing is the strategy used for phase balancing. Moreover, the power loss reduction is a significant problem in distribution networks. A common solution for power loss reduction is reconfiguration. Besides, optimal DG placement can reduce power loss and improve voltage profile. In this paper, a new method is proposed for simultaneous optimization of re-phasing, reconfiguration, and DG placement in distribution networks to reduce phase unbalancing and power loss and improve voltage profile. As there are four dissimilar objective functions, the objectives are made fuzzy and integrated as the fuzzy multi-objective function. Finally, the optimization is done by using ‎Bacterial Foraging with Spiral Dynamic‎ (BF-SD) algorithm. To demonstrate the performance of the proposed method, it is applied to IEEE 123-node test feeder. [ABSTRACT FROM AUTHOR]