3P4W Distribution System Research Articles

Design and Implementation of Solar PV for Power Quality Enhancement in Three-Phase Four-Wire Distribution System

This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

DSPACE Based Series Active Filter for Harmonics Mitigation in a Neutral Conductor for 3P4W Distribution System

dSPACE Based Series Active Filter for Harmonics Mitigation in a Neutral Conductor for 3P4W Distribution System

3-Phase 4-leg unified series–parallel active filter system with ultracapacitor energy storage for unbalanced voltage sag mitigation

This paper presents the analysis and design of a 3-phase 4-leg (3P4L) unified series–parallel active filter (USPAF) with ultracapacitor energy storage (UCES) for improving the power quality in three-phase four-wire (3P4W) distribution system. The series and parallel active filter (AF) of 3P4L USPAF system are realized by four-leg voltage source inverters (VSIs) to a common dc-link capacitor. Due to its high power density, the UCES is well-suited to supply high power for short period of time. The objective of this paper is to enhance the unbalanced voltage sag mitigating capability of the 3P4L USPAF system by adding UCES, directly connected in the dc-link. This is achieved by injecting energy from the UCES to maintain the dc-link voltage constant. Thus, the proposed system is capable of mitigating unbalanced voltage sag with zero-sequence component in the source voltage and compensating harmonic, reactive power and unbalanced current of the load in 3P4W distribution systems. The proposed scheme is validated by an experimental prototype with a 1.93F UCES bank and using dSPACE DS1103 real-time control platform in the laboratory. The experimental results show that the combined system offer improved performance to maintain the load voltage constant at its rated value during unbalanced voltage sag in the supply voltage.

3P-3W UPQC with zig-zag transformer for 3P-4W Distribution System

In this paper, a new topology is developed for a three-phase four-wire (3P4W) distribution system utilizing a zig-zag transformer along with three-phase three- wire (3P3W) Unified Power Quality Conditioner (UPQC).In this proposed topology the neutral point of the star connected transformer, used for the connection of series active power filter (APF) of 3P3W UPQC, is utilized as a fourth wire for 3P4W distribution system. The zig-zag transformer is connected near the load to compensate the neutral current that may flow toward the neutral point of the series transformer of series APF. The series and shunt APF of 3P-3W UPQC are realized by readily available three-leg voltage source inverters (VSIs). For the mitigation of different power quality problems a control technique based on synchronous reference frame (SRF) theory is used for the control of UPQC. In this control scheme of UPQC, the current/voltage control is applied over the fundamental supply currents/voltages instead of fast changing APFs currents/voltages, there by reducing the computational delay and the required sensors. The performance of the proposed topology of UPQC is analyzed through simulations results using MATLAB software with its Simulink and Power System Block set toolboxes.

A 3P-3W UPQC integrated with Star-Hexagon Transformer for 3P-4W Distribution System

A 3P-3W UPQC integrated with Star-Hexagon Transformer for 3P-4W Distribution System

A Novel Structure for Three-Phase Four-Wire Distribution System Utilizing Unified Power Quality Conditioner (UPQC)

This paper presents a novel structure for a three-phase four-wire (3P4W) distribution system utilizing unified power quality conditioner (UPQC). The 3P4W system is realized from a three-phase three-wire system where the neutral of series transformer used in series part UPQC is considered as the fourth wire for the 3P4W system. A new control strategy to balance the unbalanced load currents is also presented in this paper. The neutral current that may flow toward transformer neutral point is compensated by using a four-leg voltage source inverter topology for shunt part. Thus, the series transformer neutral will be at virtual zero potential during all operating conditions. The simulation results based on MATLAB/Simulink are presented to show the effectiveness of the proposed UPQC-based 3P4W distribution system.