Distribution Static Synchronous Compensator (DSTATCOM) is a power electronics tool joined in parallel to the system of lines to mitigate the power quality disruptions such as electric potential swell, sag, electric potential imbalance, electric potential and current harmonics voltage spike, flicker, electric potential fluctuations related to the secondary system of lines.. DSTATCOM provides electric potential control and adequate mitigation for disturbances related with distribution of system lines in community. DSTATCOM is a3-phase device that produces/ take in the dynamic power which the final outcome can transformed suitable situation to deal with specific and accurate able to change quantity of the system of lines. This article offers a critical look to the researches on the DSTATCOM for energy quality enhancement in electric distribution systems. It explains the basic elements and configuration of DSTATCOM, the operation mode of DSTATCOM, principle of operation of DSTATCOM, DSTATCOM configurations, and DSTATCOM control strategies in the electric distribution network.

To enable secondary distribution network to perform optimally, it is critical to assess the performance of the system. Optimum performance means acceptable voltage profile, increase reliability of supply, no overloading of cables and distribution transformers, absence of imbalances in both voltage and current phases and acceptable loss. This work evaluates the performance of secondary distribution network as a result of voltage losses, voltage deviation, voltage variation and voltage imbalance using MATLAB software. This paper presents a performance analysis of a typical Eskom secondary 11/0.4 kV, unbalanced secondary distribution system. The network was modeled with standard network parameters for secondary Eskom distribution network using MATLAB/Simulink Sim Power System tool box. The summary of the paper gives recommendations on effectual techniques for improving the voltage profile and reducing the voltage imbalance and voltage drop to an allowable standard.

With the ever increasing use of power semiconductor devices and information technology (ICT) equipment in the industries, homes and offices voltage quality are gaining meaningful attention to both industry and electric utility level. The lack of voltage quality causes unusually large economic losses all over the world, since voltage quality problem is one of the major power quality disturbances. This paper presents an investigative study on the 11/0.4 kV, low voltage electrical distribution network, aimed at analyzing voltage unbalance and variation problems and recommending an effective method of improving the voltage profile and reducing the voltage unbalance and variation to allowable standard. The network was modelled with the distribution network standard parameters for low voltage distribution network using MATLAB/Simulink Sim Power System tool box. The simulation results with distribution length 0.5 km for balanced three phase load is within the permissible voltage profile of ±5%, reaching the customers, meaning it is admissible for customers use also it was established that an inadmissible poor voltage profile reaching the customers at the network end of distribution network lengths 0.8 km to 5 km which is less than the standard minimum permissible limit of -5%, of nominal voltage value

This study addresses the effective mitigation of power quality disturbance such as unbalanced voltage, voltage fluctuation, voltage variation of secondary distribution network using dynamic voltage restorer (DVR). To make distribution system operate at its best performance and minimum loss, DVR is employed. The proposed system is designed using MATLAB/Simulink in Sim Power System tool box. Considering, nevertheless, that standard acceptable performance implies correct voltage profile, minimum loss, no phase shift for voltage and current, absence of overloading of transformers and electrical wires, and acceptable frequency deviation. The new setup of DVR has been put forward using dq0 controller and proportional integral (PI) controller method to improve voltage profile, correct unbalance voltage and enhance power quality problems in secondary distribution network. The simulation results attest to the ability of the proposed DVR configuration in mitigating the power quality problems in secondary distribution network.

This paper presents an investigative study on a selected 11 kV distribution feeder network in Akure township, Nigeria, aimed at evaluating power distribution problems and solution proposals for effective application of existing 11 kV feeders for power supply within Nigeria. Based on peak loads recorded on the feeder for 8 years a long term load forecast up to 2021 was carried out using "Trend' and "Growth' functions in Excel worksheet. These functions use Method of Least Squares. The peak network load is 8 MW and the expected load in 2021 is 14.5 MW (18.5 MVA at 0.8 power factor) after an exponential growth rate of 0.6 MW per annum. There is need to increase the rating of the power transformer feeding the feeder in order to enhance the security power supply to the network. Furthermore, the Power Company must provide standard input voltage (1.05x11 kV) to the network in order to normalize end-users voltage quality.

With ever increasing use of semiconductor devices and information technology (ICT) equipment in the industry, homes and offices, power quality is gaining attention to both industry and the electric utility. Power voltage quality cause huge economic losses to businesses all over the world. It is estimated to cost industry and commerce about €100 billion per annum in European Union, since voltage quality problem is one of the major power quality disturbances. This paper presents an investigative a study of the 11/0.4 kV, low voltage electrical distribution network and analyzes voltage unbalance. It recommends an effective method of improving the voltage profile and reducing the voltage unbalance to acceptable standard. The network was modelled using distribution network standard parameters for low voltage distribution network using MATLAB/Simulink sim power system tool box. The simulation results show that the percentage voltage unbalance, correct voltage profile and minimum voltage drop of 0.5 km distribution feeder line is of standard acceptable statutory limit, hence the distribution line operates at optimum performance. However, it is also established that the voltage profile for distribution network feeder lengths of 0.8 km to 5 km for balanced and unbalanced distribution lines from the beginning to the customer terminal of the distribution lengths are less than the acceptable allowable limit of – 5 %, of the nominal voltage value, hence voltages are inadmissible for customers use. Moreso, the percentage voltage unbalance, voltage profile and voltage drop on 0.8 km to 5 km distribution feeder line are all less than standard acceptable statutory limit, hence the distribution line operates below optimum performance. It was established that mitigating these problems require the electricity distribution company to install an effective voltage boosting devices along the network lengths in order provide admissible, permissible and normalize end users standard acceptable voltage.

With the global trend of restructuring in electricity market, providing affordable, reliable and quality electric power by service providers to customers the end users of electric energy are of immerse concern. Several initiatives have been taken by utilities to improve power quality in low voltage electric power distribution network but the inadequate operation/performance of the conventional compensation devices to mitigate the poor power quality problems have prompted the use of custom power device such as the dynamic voltage restorer (DVR). Dynamic voltage restorer (DVR) is an advanced power electronics based compensation device which is series connected to the distribution network through boosting transformers. DVR aimed at improving the voltage profile, enhancing the reliability and good quality of power flows in low voltage electric power distribution networks. The DVR is a highly efficient device, the principle is based on the voltage source inverter (VSI) which injects the appropriate missing voltage in series with the system voltage to correct the voltage variations experienced in the distribution feeder lengths. The dependability, robustness and effectiveness of the DVR control and power scheme in respect of the response to voltage disturbances at normal mode operation of three phase balanced loads is presented using the MATLAB simulation results carried out in Power System Sim Tool box. The balance of the paper gives recommendations on effective methods for improving the voltage profile and reducing the voltage variation to an allowable standard.

Dynamic Voltage Restorer (DVR) is a series connected power electronics based custom power device that is used to improve voltage disturbances in low voltage electrical power distribution network. Power quality requirement is one of the most important concerns for power system. The parts of the DVR is made up of voltage source inverter, injection/booster transformer, a harmonic filter, an energy storage device and a bypass switch. The DVR is used to inject three phase voltage in series and in synchronism with the network voltages in order to compensate voltage disturbances with a benefit of active /reactive power control. This paper presents a review of the researches on the dynamic voltage restorer application for power quality improvement in low voltage electrical power distribution networks. It describes power quality issues, principle of operation of DVR, basic components of DVR, DVRs control topologies in distribution network, DVR control strategies and compensation techniques.

Insulators are essential components for electric power transmission, especially in high voltage direct current (HVDC) transmissions. They are expected to operate effectively at all times, even in harsh weather and environmental conditions (wind, contamination and humidity) where they are subjected to various stresses. This paper presents the effects of contaminants at different levels of conductivity on both electric field and current density distribution along a 22 kV silicon rubber insulator. A 2D model of the insulator was developed using a FEM software package: FEMM 4.2. The model incorporates the real dimensions insulator geometry and the material properties. The simulation was carried out on a clean and contaminated SIR insulator at the rated insulator direct current voltage level. The areas where the maximum field intensity occurred have been studied for all surface conditions. The results show that both the intensity of electric field and current density increases with an increase in surface conductivity.

With the ever increasing use of semiconductor devices and information technology (ICT) equipment in the industry's, homes and offices voltage quality are gaining meaningful attention to both industry and the electric utility. Poor voltage quality cause unusually large economic losses all over the world, since voltage quality problem is one of the major power quality disturbances. This report provides an investigative study on the typical 11/0.4 kV, low voltage electric power distribution network. The network was modelled with standard network parameters for low voltage typical electric power distribution network using MATLAB/Simulink Sim Power System tool box. Results obtained from simulation with distribution feeder length 0.5 km for unbalanced 3-phase loads are within the acceptable nominal voltage tolerance range of ±5 % of the nominal voltage value at the customer's terminal. While this is admissible for customers close to the infeed terminal, it was established that an inadmissible poor voltage reaches the customers at the end of the distribution network for network lengths 0.8 km to 5 km. Voltages measured here were less than the standard allowable limit of 0.95 p.u, of nominal voltage value. The summary of the paper gives recommendations on effective methods for enhancing voltage profile and correcting the unbalanced voltage to an allowable standard.

The compensation of voltage unbalance disturbance in low voltage electric power distribution system using improved d-q-o and PI controller techniques is the focus of this paper. There are several methods to mitigate voltage unbalance. A very effective method of voltage unbalance compensation is the use of dynamic voltage restorer. Dynamic voltage restorer is a series-connected advanced power electronic custom-based tool. It is employed to mitigate voltage disturbances in low voltage electric power distribution network. Dynamic voltage restorer is installed in the network between the source voltage and the loads to correct voltage disturbances affecting the load voltage. This report presents the modelling of dynamic voltage restorer for voltage unbalance correction in a low voltage 11/0.4 kV electric power distribution network using MATLAB/Simulink Sim Power System tool box. Results obtained from simulation with distribution length 0.5 km to 5 km for 3-phase unbalanced loads are within the permissible nominal voltage tolerance of ±5% at the customer's terminal when dynamic voltage restorer is connected to the network. This is not the case when a dynamic voltage restorer is not plugged in. The results obtained demonstrate the effectiveness of this device's performance in improving voltage unbalance in a low voltage electrical power distribution from lengths 0.5 km to 5 km. The balance of the paper discusses some recommendations for an efficient, reliable and cost-effective method for improving voltage profile and reducing the voltage unbalance in 3-phase unbalance load to acceptable standards.

This work addresses the compensation of power quality disturbance in electric power distribution network as a result of voltage variation and voltage unbalanced using one of the most effective power electronics based custom power controller known as Dynamic Voltage Restorer (DVR). DVR usually connected between the source voltage and the customer load. The new setup of DVR has been put forward using dqo controller and proportional integral (PI) controller method. The simulations are achieved using MATLAB/Simulink Sim Power System tool box. The simulation results attest to the effectiveness of the proposed DVR configuration in compensating the power quality problems in secondary distribution system. The simulation results runs are presented with different settings of parameter used in the model in order to help the validity of the function of DVR in enhancing the quality of power supply at customer side.

This paper presents an investigative study on a selected 11 kV distribution feeder network in Akure township, Nigeria. The study was aimed at evaluating power distribution problems and solution proposals for effective application of existing 11 kV feeders for power supply within Nigeria. Time series load data on the sample feeder were analyzed to evaluate feeder failure rates, mean down times per outage, and availability. The network was surveyed to produce a map and circuit diagrams of spatial relationships of its elements. Loading and voltage profiles of the network were evaluated using direct measurements at 63 distribution transformers and computation of loading coefficient and currents. Solutions were proposed and tested computationally with consideration of 10 year future load estimate. Problems established include: low network availability, predominantly due to load shedding and short circuit faults; and inadmissibly poor voltage profile due to substandard source-end voltage. It was established that mitigating these problems require standard routine and planned maintenance practice and quick repair response to minimize failure rate and mean downtime: if network availability of 0.9 is acceptable, then a minimal failure rate of 1 event/week must be cleared under 24 hours; at a desired 0.999 availability, at failure rate of 1 to 6 events per year, the outage clearance would range from 9 to 1 hour. Furthermore, the Power Company must provide standard input voltage (1.05-11kV) to the network in order to normalize end-users voltage quality.