Investigations on Performance Improvement of Electrical Power Distribution System with Incorporation of DSTATCOM and Distributed Energy Sources

Abstract

In recent years, the usage of nonlinear loads in the distribution system has increased drastically. Because of these nonlinear loads, power qual- ity problems result in the system. The power quality problems such as voltage sag-swell, harmonics, voltage icker and unbalance in the system voltage will appear. The current situation in the distribution system has become complicated due to the injection of power from renewable energy sources into the distribution grid. The integration of distributed gener- ation source to the distribution network has created more power quality issues such as voltage unbalance and harmonics problem. Due to these facts, in recent years, globally there is more concern for addressing power quality problems in modern distribution network. Custom power device is one of the solutions to solve power quality issues in distribution system. Distribution Static Compensator (DSTATCOM) is used in distribution system for performance improvement. This device supply the reactive power to the distribution system to ensure power factor improvement, voltage regulation along with harmonics mitigation, load balancing and neutral current compensation. Also, DSTATCOM is expected to enhance the performance of distribution system in presence of distributed genera- tion sources. Firstly, the e cient working of DSTATCOM depends on the control algo- rithm which is used to generate switching pulses for controlling devices. Most of controller, proposed in the literature, considers only positive se- quence component. To overcome these problems, there is a need of devel- oping a control strategy which has the ability to reduce negative sequence components and have advantages of both current and voltage control mode for the unbalanced load condition. In this work an improved control al- gorithm is proposed. This research work presents investigation of per- formance of DSTATCOM with proposed positive sequence controller and proposed positive and negative sequence controller in distribution system under di erent operation scenarios. The performance of proposed con- trollers are analysed for a test system and a 9 bus distribution system. Secondly, in modern power system, the penetration of renewable energy sources has increased since there are no negative impact on environment. v According to grid codes, renewable energy sources are not required to contribute to restore the voltage stability. As a result, the reliability and voltage stability of the power grid is negatively a ected due to distur- bances. The DSTATCOM can be used to improve the low voltage ride through behavior of micro grids in both grid connected and islanded mode of operation. The compensation of positive and negative sequences com- ponents are required to support voltage restoration as well as the power grid stabilization and DSTATCOM should be able to give satisfactory per- formance in improving low voltage ride through capability. In this work, the performance of DSTATCOM in di erent fault scenario and low volt- age ride through capacity of controller are studied. Lastly, to get e cient operation, the DSTATCOM should be optimally placed and size should be determined. The primary goal of this work is to lessen the active power loss of the radial distribution system with voltage pro le improvement. In this report, Ant Colony Optimization technique is utilized for the ideal position of DSTATCOM in the distri- bution framework for lessening of line losses and rise of voltage pro le. Later, the performance is analysed by incorporating the DSTATCOM at an optimised location in a practical system. When DG is incorporated into the system, the characteristics of the system will change; it will lead to more power quality issues in the power distribution system. This op- erating scenario should also be considered during performance analysis of DSTATCOM and there is a need to study impact of DSTATCOM and DG on distribution system. The MATLAB simulation is carried out and the performance of the pro- posed controllers are analysed with di erent cases by considering unbal- anced load conditions and step change in the load. Also, the voltage ride through capability of DSTATCOM with proposed controller is studied. The observed results demonstrate that the overall system performance improves with the proposed positive and negative sequence controller. The ant colony optimisation algorithm is applied on IEEE 33 and a real time practical 207 radial distribution system by using MATLAB program. Results demonstrate the reduction in line losses and rise in voltage pro le for all test frameworks. From the impact analysis of distributed generators and DSTATCOM on distribution system it is observed that the proper se- lection of DSTATCOM and distributed generator are need to be done for improving distribution systems performance.