scholarly journals Multi-Level Inverter Topologies Based UPQC Applied to Distribution Systems for Power Quality Improvement

2019 ◽  
Vol 8 (4) ◽  
pp. 5129-5135

At distribution side most type of loads connected are non-linear types. These loads adversely affect the power quality of the system. If not rectified at times they may distort the sine wave at source side. This paper presents a power quality conditioner which is designed using multi-level inverter (MLI). The advantage that the proposed MLI has over conventional one is that it requires less number of components as compared to the conventional. Also it improves the utility profile by improving harmonic content at output side. The proposed MLI based Unified power Quality Conditioner (UPQC) improves the grid profile at non-linear loading by prohibiting the propagation of high content harmonic load current at source side. The proposed topology has inherent active filtering capability by virtue of which there has been seen a good mitigation of power quality issues at point of common coupling. Comparative analysis of the proposed topology with the conventional MLI is also presented. The comparison of results is also presented in terms of linear and non-linear loading in a UPQC compensated distribution system.

Author(s):  
Jasti Venkata Ramesh Babu ◽  
Malligunta Kiran Kumar

Power quality is one big issue in power system and a big challenge for power engineers today. Electrical consumers (or otherwise load devices) expect electrical power received power should be of first-class. Bad quality in electrical power directs to fuse blowing, machine overheating, increase in distribution losses, damage to sensitive load devices and many more. DSTATCOM is one of the FACTS controllers designed to improve the quality in electrical power and thus improving the performance of distribution system. This paper presents a multilevel DSTATCOM topology to enhance power quality in power distribution system delivering high-quality power to the customer load devices. Diode-clamped structure is employed for multi-level DSTATCOM structure. ‘PQ’ based control strategy generates reference signal which is further processed through level-shifted multi-carrier PWM strategy for the generation of gate pulses to multi-level DSTATCOM structure. Simulation work of proposed system is developed and the result analysis is presented using MATLAB/SIMULINK software. Performance of multi-level DSTATCOM topology is verified with fixed and variable loads.


Author(s):  
May Phone Thit

Nowadays, power quality is one of the major problems in electric power distribution system. The poor power quality at distribution level can affect the operation and performance of sensitive and critical loads. In the distribution systems, poor power quality results in various problems such as higher power losses, harmonics, sag and swells in the voltage, and poor power factor., etc. Unified Power Quality Conditioner (UPQC) is the only versatile device which can mitigate several power quality problems related with distribution system. A UPQC that combines the operations of a Distribution Static Compensator (D-STATCOM) and Dynamic Voltage Restorer (DVR) together with the shunt and series active control devices. UPQC can solve the problems related to the voltage/current harmonics, voltage sag/swell and unbalance in distribution system. To evaluate the performance improvement in the system, a model of UPQC is developed in MATLAB/SIMULINK with a typical distribution network. In this research, UPQC is applied for power quality enhancement of Myaungtagar industrial distribution substation, Myanmar. Enhancements in power quality by UPQC are evaluated under maximum load condition.Keywords—Power Quality, UPQC, Series Controller, Shunt controller, Harmonics


Sending power with good quality is the main objective of electrical transmission system. The load nature, in particular non-linear loads, makes the current at the point of common coupling (PCC) to include harmonics which further affects the other loads connected at PCC. Power quality improvement and management is an important study for the enhancement of electrical transmission and distribution systems to enrich the quality of power delivered at the utilization point. DSTATCOM is one among the FACTS controllers to improve the power quality by nullifying the effect of harmonics at PCC. This paper presents the analysis of dual DSTATCOM topology. In this each DSTATCOM is burdened such that the total compensating currents is shared between the two. Dual STATCOM topology is tested and the result analysis is shown with varying non-linear type loading conditions. Dual DSTATCOM is controlled using Instantaneous Reactive Power theory control logic. Parallel DSTATCOM has the advantage of reduction of switch rating and switching losses. The simulation work is carried out using Matlab/Simulink software


2019 ◽  
Vol 13 (1) ◽  
pp. 196-211
Author(s):  
Narinder Kumar ◽  
Ashwani Kumar

Purpose The purpose of this paper is to analyze annual energy expenditure in the presence of non-linear load and substation voltage harmonics in distribution systems. Economic assessment of non-sinusoidal energy is a challenging task that involves complex computations of harmonic load powers and harmonic line losses. Design/methodology/approach The paper evaluates fundamental and non-sinusoidal components of electrical energy by applying backward/forward sweep technique in distorted distribution systems. This work involves harmonic power computations at the substation by including harmonic losses occurring in various lines of the distribution system. Findings The paper found that annual energy expenditure significantly depends upon the non-linear load, supply voltage harmonics and type of tariff structure considered in the distribution system. Impact of individual harmonic orders on the energy billing is also assessed. Originality/value The paper concludes that considering harmonic distortions in the distribution system analysis would help electricity regulators formulate adequate pricing structures, which would further generate appropriate economic signals for electricity utility and the consumers.


2019 ◽  
Vol 8 (2) ◽  
pp. 6080-6088

The significant usage of power semi-conductor devices in modern single or multi-feeder distribution system is increasing a lot in present situation. The non-linear characterization of power distribution is highly responsible for degradation of power-quality standards. The usage of large-sized non-linear loads provokes the harmonic pollution, voltage interruptions, voltage sag/swell issues are the key problems faced by distribution systems. Over the various compensation methodologies, the highly validated universal device is Unified-Power Quality Compensator. The multi-feeder universal devices play a prominent role and provide the attractive performance with improved characteristics in multi-feeder distribution system. In this work, Multi-Feeder UPQC device is used to compensate all voltage and current related PQ issues in multi-feeder distribution systems and also furnishes load-sharing between adjacent feeders, reduce the power-shortages, maximizes the stable performance. The performance evaluation of proposed MF-UPQC is verified under various case studies with the help of Computer-Simulation tool, results are validated with improved PQ features.


Distribution systems have been facing serious problems of harmonics load current mainly due to advancement in power electronic based and other non-linear loads. The DSTATCOM has been widely used to mitigate the load current harmonics problems in distribution system. The power quality improvement is one of the major problems when the distribution side load increases with non-linear loads like electric vehicles, laptops, PCs etc., There are some power quality mitigation technique available at the load side where the electronic chargers works with unity power factor (UPC) control. But many DC loads are connected without the UPC. So, it is a need for a device which corrects the real and reactive power at the distribution level. The DSTATCOM is connected to the Indian distribution system with 415V, 50Hz. In this paper the linear loads and nonlinear loads are coupled to the system and analysis with DSTATCOM and without DSTATCOM cases are presented.


Author(s):  
Gunjan Varshney ◽  
Durg S. Chauhan ◽  
Madhukar P. Dave ◽  
Nitin

Background: In modern electrical power distribution systems, Power Quality has become an important concern due to the escalating use of automatic, microprocessor and microcontroller based end user applications. Methods: In this paper, power quality improvement has done using Photovoltaic based Distribution Static Compensator (PV-DSTATCOM). Complete simulation modelling and control of Photovoltaic based Distribution Static Compensator have been provided in the presented paper. In this configuration, DSTATCOM is fed by solar photovoltaic array and PV module is also helpful to maintain the DC link voltage. The switching of PV-STATCOM is controlled by Unit template based control theory. Results: The performance of PV-DSTATCOM has been evaluated for Unity Power Factor (UPF) and AC Voltage Control (ACVC) modes. Here, for studying the power quality issues three-phase distribution system is considered and results have been verified through simulation based on MATLAB software. Conclusion: Different power quality issues and their improvement are studied and presented here for harmonic reduction, DC voltage regulation and power factor correction.


2021 ◽  
Vol 11 (2) ◽  
pp. 774 ◽  
Author(s):  
Ahmed S. Abbas ◽  
Ragab A. El-Sehiemy ◽  
Adel Abou El-Ela ◽  
Eman Salah Ali ◽  
Karar Mahmoud ◽  
...  

In recent years, with the widespread use of non-linear loads power electronic devices associated with the penetration of various renewable energy sources, the distribution system is highly affected by harmonic distortion caused by these sources. Moreover, the inverter-based distributed generation units (DGs) (e.g., photovoltaic (PV) and wind turbine) that are integrated into the distribution systems, are considered as significant harmonic sources of severe harmful effects on the system power quality. To solve these issues, this paper proposes a harmonic mitigation method for improving the power quality problems in distribution systems. Specifically, the proposed optimal planning of the single tuned harmonic filters (STFs) in the presence of inverter-based DGs is developed by the recent Water Cycle Algorithm (WCA). The objectives of this planning problem aim to minimize the total harmonic distortion (THD), power loss, filter investment cost, and improvement of voltage profile considering different constraints to meet the IEEE 519 standard. Further, the impact of the inverter-based DGs on the system harmonics is studied. Two cases are considered to find the effect of the DGs harmonic spectrum on the system distortion and filter planning. The proposed method is tested on the IEEE 69-bus distribution system. The effectiveness of the proposed planning model is demonstrated where significant reductions in the harmonic distortion are accomplished.


2019 ◽  
Vol 8 (2S8) ◽  
pp. 1124-1132

The essential focus of this endeavor is examination of three phase four wire UPQC available for use structures by neural framework. The bound together power-quality conditioner (UPQC) is used to calm the current and voltage-related power-quality (PQ) issues in the meantime in three-arrange four-wire course structures. Among most of the PQ issues, voltage hang is a significant issue in three-arrange four-wire scattering systems. In this paper, another procedure is proposed playing out the plan parallel electrical cable trim. As such, despite when only a three-organize three-wire control structure is available at a plant site, the UPQC can do control line pay for presented loads that require a fair-minded channel to work. Not exactly equivalent to the control philosophies used in most of UPQC applications in which the controlled sums are nonsinusoidal, this UPQC uses a twofold pay technique, with the ultimate objective that the controlled sums are continually sinusoidal. Neural System controller have been used to make the proposed methodology online for least real power implantation with UPQC by using the PSObased data for different voltage rundown conditions. In the proposed system PI controller substituted by NN controller for better precision.


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