Three-phase Four-wire System Research Articles

Receiving-End Voltage Compensation Method with NPC-Inverter-Based Active Power Line Conditioner in Three-Phase Four-Wire Distribution Feeder

This study proposes a receiving-end voltage compensation method employing a phase-specific reactive power control strategy with a neutral-point-clamped (NPC) inverter in a three-phase four-wire distribution system. The principle of the proposed receiving end voltage compensation method is explained. Further, the proposed control strategy can solve the problems of the three-phase, four-wire distribution system, which are an increase in the neutral-line current and the unbalanced voltage. Computer simulation is performed to confirm the validity of the proposed method. The simulation results indicate the receiving-end voltages can be compensated using the proposed method.

ВИМІРЮВАННЯ ТА КОМПЕНСАЦІЯ НЕАКТИВНИХ ПОТУЖНОСТЕЙ ТРИФАЗНИХ СИСТЕМ ЕЛЕКТРОЖИВЛЕННЯ ЗАСОБАМИ ПАРАЛЕЛЬНОЇ АКТИВНОЇ ФІЛЬТРАЦІЇ

In this paper, the power theory of three-phase power supply systems was further developed by substantiating new formulas for calculating the unbalance power of three-phase four-wire power supply systems based on the measurement of active and reactive powers of individual phases, which can be used to form compensation signals in distributed active filtering with centralized control. A new structural scheme for controlling an autonomous shunt active filter with extended functionality and increased speed is proposed, which can be used in both three-wire and four-wire power supply systems. Computer modeling confirmed the adequacy of the new formulas for calculating the unbalance power components and the effectiveness of the proposed active filtering strategies to minimize power losses in the transmission line. References 11, figures 3, table 1.

A multifunctional inverter power quality coordinated optimization strategy based on comprehensive evaluation

The large-scale integration of renewable energy sources and power electronic devices has led to increasingly dispersed and networked characteristics of power quality disturbances in distribution systems. Traditional control devices, limited by their fixed-point control, no longer meet the development needs of modern distribution systems. Considering the distribution and structural characteristics of the current new-type sources and loads, a multifunctional inverter power quality coordinated control strategy based on comprehensive evaluation is proposed. This strategy aims to achieve power quality coordinated control by utilizing optimal compensation capacity while the grid-connected inverter provides active power output. Firstly, the traditional ipiq power quality detection method is analyzed and improved to enable detection of harmonics, reactive power, and three-phase imbalance currents in single-phase systems or three-phase four-wire systems. Secondly, in the power quality assessment, a balanced algorithm is employed to obtain the comprehensive evaluation index of power quality, thereby improving the deficiencies of single-weight evaluation. Next, to ensure the grid-connected inverter achieves optimal power quality coordinated control with minimal compensation capacity, an optimization compensation function is established between compensation capacity and comprehensive power quality index. This function is optimized using non-dominated sorting genetic algorithm to enhance equipment utilization and system economy. Finally, the feasibility and effectiveness of the proposed method are validated through simulations, demonstrating the achievement of optimal capacity configuration for power quality coordinated control while ensuring active power output by the grid-connected inverter.

Currents’-Physical-Component-Based Reactive Power Compensation Optimization in Three-Phase, Four-Wire Systems

In this paper, we aim to address the limited capacity of compensation devices by enhancing their utilization rate by applying the currents’ physical component (CPC) theory for reactive power optimization in three-phase four-wire systems. When reactive currents cannot be fully compensated for, we propose using CPC theory to generate reference currents for the compensation devices. Weight coefficients associated with different reactive current components are introduced, enabling flexible combinations of these independent current components. The maximum output amplitude of the three-phase current from the compensation device serves as a constraint condition, allowing for the calculation of reference currents under various compensation targets. Additionally, a reactive current optimization compensation scheme focusing on loss reduction is selected. The simulated annealing–particle swarm optimization (SA-PSO) hybrid algorithm is employed to solve the optimization mathematical model. The discussed calculations, current waveforms, and voltage waveforms are generated using the constructed mathematical model and then used for a theoretical explanation. The simulation verifies the feasibility of the proposed method.

Enhancing power quality with optimized PI controller in three-phase four-wire wind energy system

Enhancing power quality with optimized PI controller in three-phase four-wire wind energy system

Small-Signal Stability Analysis of Three-Phase Four-Wire System Integrated With Single-Phase PV Inverters Considering Phase to Phase Coupling

Small-Signal Stability Analysis of Three-Phase Four-Wire System Integrated With Single-Phase PV Inverters Considering Phase to Phase Coupling

Budeanu’s Distortion Power Components Based on CPC Theory in Three-Phase Four-Wire Systems Supplied by Symmetrical Nonsinusoidal Voltage Waveforms

Budeanu’s power theory, in its fundamental version, describes single-phase sinusoidal and nonsinusoidal systems. Over time, this elementary description has been extended to three-phase three-wire and four-wire systems, regardless of power conditions. Initially, three-phase systems were considered as three independent single-phase systems. A distinct approach was introduced by Czarnecki in his power theory (Currents’ Physical Components—CPC). The energy description and reference of the equivalent parameters of the load are comprehensive in the context of three-phase systems; Czarnecki treats such systems as a whole. This paper introduces a mathematical model to expand the basic Budeanu theory for three-phase four-wire (3-p 4-w) systems powered by symmetrical and nonsinusoidal voltage sources. The proposed approach is based on mutual elements between the fundamental Budeanu theory and the CPC theory, treating the 3-p 4-w system as a whole. In the extended Budeanu theory model, equations for the Budeanu reactive current and the Budeanu complemented reactive current are derived. The article also demonstrates their orthogonality concerning the remaining components, indicating that each of the seven components can exist independently of the others. Furthermore, in the extended Budeanu theory, it is possible to identify which equivalent parameters of the load are responsible for the individual currents (powers) and which components are associated with the total distortion power proposed by Budeanu in 1927. All of the calculations were performed in Matlab/Simulink 2023b software.

Three-phase four wire shunt active power filter based on Simplified Backstepping technique for DC voltage control

This work presents a simulation of Three-Phase Four-Wire Shunt Active Power Filter (SAPF) destined to suppress harmonic currents generated by nonlinear loads. The SAPF guarantee also the compensation for unbalanced nonlinear load currents, reactive power and harmonic neutral current. The identification method is based on the synchronous reference frame. In order to have good performances of DC voltage control, simplified Backstepping control for three-Phase four-Wire (SAPF) system is proposed. Complete simulation of the resultant active filtering system validates the efficiency of the proposed simplified Backstepping control law over to the traditional control with PI controller.

Research and development of a virtual instrument for measurement, analysis and monitoring of the Power Quality

This paper is about the design of a power quality monitoring system based on LabVIEW for factory power quality defined in the IEEE Standard 1459-2010 [1] for single-phase, three phase three-wire and three-phase four-wire power systems [1] and [2]. With LabVIEW as development platform, composed by some functional modules such as data acquisition, data processing, data storage, and data report, etc. defined in International standards concerning electrical power quality Standard EN 50160 [3] and [4]. This system has advantages of better analyzed affection and low cost, and can be extended easily.

Neural-Networks and Synchronous Reference Frame Applied in the Harmonic Compensation with a Three-Phase Parallel Active Power Filter

This paper presents an alternative method based on artificial neural network, which is used to obtain the reference currents for harmonic current suppression and reactive power compensation in a shunt active power filter applied to three-phase four-wire system. The neural network consists of a multilayer perceptron, which is trained to estimate the peak amplitude of the load fundamental component currents. The performance of the proposed artificial neural network is evaluated by computer simulation, and it is compared with the method based on synchronous reference frame

Power Quality Improvement on 11kV/440V Distribution System using DSTATCOM

At the PCC and source side, current and voltage harmonics are compensated by utilizing a distribution static compensator. In this work, we also compensated for voltage control and reactive power correction. An improved reference current switching signal is suggested using a synchronous reference frame control technique. The analysis is done on an 11kV/440V three-phase four-wire unbalanced nonlinear load distribution system. The DC link voltage and harmonic reduction of the suggested distribution system performance is compared with the PI and fuzzy logic controllers. Harmonic distortion is reduced, and reactive power is successfully compensated with the suggested method. These simulation results are obtained by MATLAB/SIMULINK software.

Control strategies for active power filters

In this paper a comparison between strategies for extracting the three-phase reference currents for active power filters is shown. The performance of these strategies will be evaluated under different source and load conditions. The study has been applied to a three-phase four-wire system in order to include imbalance. It will be shown that under balanced and sinusoidal voltages, harmonic cancellation and reactive power compensation can be achieved by all the methods. However, when the voltages are distorted and/or unbalanced, the compensation capabilities are not equivalent. It will be proved that some strategies do not offer an adequate solution when the mains are not ideal, including harmonics or imbalance.

Optimal Planning of Hybrid AC/DC Low-voltage Distribution Networks Considering DC Conversion of Three-phase Four-wire Low-voltage AC Systems

Optimal Planning of Hybrid AC/DC Low-voltage Distribution Networks Considering DC Conversion of Three-phase Four-wire Low-voltage AC Systems

Algorithm for passive reactive power compensation of an unbalanced three-phase four-wire system using capacitors ensuring minimum line losses

Currently in three-phase distribution networks, especially low-voltage networks, there are some inefficient powers. These are defined as reactive power, unbalanced power owing to linear loads, power owing to supply unbalanced voltage, and harmonic power. This has given rise to the concept of power quality. To improve power quality, devices called active filters have been developed. These devices eliminate all the inefficient power. However, for most processes, the elimination of reactive power needs to be from a price/performance perspective because the use of active filters is very expensive. Therefore, the use of capacitor banks in any of their versions (single-phase, three-phase, scalable battery, SVC, etc.) is the most economical and sufficient solution. In this study, a calculation algorithm is proposed to obtain compensators for the inductive reactive power of the load, consisting only of single-phase capacitor banks. These capacitors are designed to minimise losses in the supply line, which are lower than those obtained using the minimum loss line (MLL) strategy. The resulting compensator consists of three, two, or one capacitor, depending on the load characteristics.

Design and Assessment of Unified Multi-Input Multi-Output Converter Based Islanded Microgrid for Rural and Remote Areas

—This paper addresses an islanded microgrid (MG) for rural and remote areas (RRAs) that aims to provide reliable electricity, considering the challenges posed by geographical constraints on solar power generation. Solutions and development for specific applications in RRA, can’t form MG to fulfill all needs of RRA at once because their integration creates circulating currents, power losses & compromised power quality. To overcome this, a robust, techno-economical, low-maintenance all-in-one single-synchronized compact solution has been introduced for establishing and upgrading existing islanded MGs for RRA. The proposed solution is Unified Multi-Input Multi-Output (U-MIMO) based islanded MG (MMG), designed to support multi-location PV arrays catering to various loads. It has three-phase four-wire system, battery management system (BMS) and supports DC load/E-Vehicles. The objectives are to enhance the utilization of solar power, enable controllability of power generation & daily load demands and facilitate ease of implementation. The experimental results demonstrate that U-MIMO is effectively compatible with all types of loads (AC/DC), allowing the integration of PV arrays across multiple locations even in unbalanced irradiance conditions while maintaining the total harmonic distortion (THD) below 5%. This showcases the versatility and reliability of the proposed U-MIMO-based MMG for sustainable electricity generation in RRA.

D-Q Impedance Modeling and Stability Analysis of a Three-Phase Four-Wire System With Single-Phase Loads

D-Q Impedance Modeling and Stability Analysis of a Three-Phase Four-Wire System With Single-Phase Loads

Power quality enhancement using a novel SAPF control scheme employing high selectivity filter

Abstract Severe issues such as degradation of power quality and efficiency have surfaced in past few years due to extensive use of power electronic converters for conversion and control in power system. The shunt active power filter (SAPF) has gained attention as a competent solution among researchers. However, most SAPF control schemes render ineffective results under non-ideal supply conditions. A novel single-phase p–q scheme based on high selectivity filter (HSF) for extraction of reference compensation currents is proposed in this paper. A three H-bridges (3HB) voltage source inverter (VSI) topology of SAPF is considered and its dc-link voltage is regulated using an Enhanced Bacterial foraging optimization (BFO) based PI controller. This topology along with the proposed SAPF control scheme can guarantee improved APF performance as each phase of the three-phase four-wire system can be controlled independently. Extensive investigations are carried out using MATLAB/Simulink simulations followed by real-time performance verification in Opal-RT Lab. The effectiveness is assessed in terms of current harmonics, excessive neutral current and current unbalance compensation. The results obtained with proposed scheme when compared with conventional three-phase and single-phase p–q schemes employing low-pass filters (LPF) yield remarkably superior results under ideal, distorted and unbalanced supply and unbalanced loading conditions.

Improved CPC-based parameter calculation of passive balancing compensation in three-phase four-wire systems with unbalanced loads

The unbalanced loads in low voltage three-phase four-wire(3P-4W) systems increase the energy and the voltage losses of the power supply system, and even cause serious voltage deviations. The passive compensation method using the Currents’ Physical Components (CPC) – based power theory does not consider the voltage losses of phase and neutral line impedances, and it is only suitable for the situations of symmetrical voltage. Under the conditions of supply voltage distortion, load unbalance and the consideration of line impedances, this paper improves the calculation method of passive compensation parameters oriented the current components in four-wire systems, which can make the system work efficiently with the fundamental optimal working current balanced without harmonic amplification. The effectiveness and adaptability of the proposed method to the background conditions are verified, based on the comparison of MATLAB / Simulink simulation results.

Current Unbalance Monitoring In Four-Wire System Based on Fuzzy Logic

The daily consumption profile of electric power is different for each electrical customer, which is random and unpredictable, especially in residential, commercial, and educational areas, which are dominated by single-phase electrical loads. The abundance of this one phase load can enhance the current unbalance of the three-phase four-wire system, and will cause several other power quality problems e.g., Increasing Neutral current, displacement of neutral point, Increasing heating in one phase and losses in distribution network. However, the PIUR (Phase current unbalance rate) value as one of indicators of power quality must not exceed the threshold recommended by the NEMA standard, which is a maximum of 30%. For this reason, this paper proposes a current unbalance monitoring based on Fuzzy Logic to produce an unbalance quality (excellent, good, moderate, bad, and poor) that can be monitored by electric customers globally. The unbalance quality is very useful for electric customers to rearrange their single-phase load installation so that the power quality indicator value is expected to be within the allowable range. In addition, this prototype (proposed system) is also able to provide great convenience for electric customers to monitor the changes of profile uses of loads, and at the same time can detect the emergence of disturbances early that may occur in each phase.

Reduced Reference Frame Transformation Assessment in Unbalanced Three-Phase Four-Wire Systems

Three-phase four-wire systems require a reference frame similar to that used in 3-phase 3-wire system configurations that allow them to be easily analysed, modelled and controlled. A new reference frame called Reduced Reference Frame (RRF) was presented by the authors in a previous work to satisfy these objectives. This is based on the locus of the voltage space vector which is used to perform a transformation applied to 3-phase 4-wire systems. This paper uses the proposed RRF to demonstrate the benefits of this transformation under different conditions of load or voltage imbalance. To this end, the different types of imbalances considered are studied by comparing the results in the classical αβγ axes, the so-called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mno</i> -transform specifically developed for 3-phase 4-wire systems and the RRF coordinates. In addition, a theoretical identification of some types of imbalances is done comparing the simulation results and the fundamentals of the RRF.