scholarly journals DSTATCOM for Harmonics Mitigation in 3-Phase 3-Wire Sytem

10.29007/nkxw ◽  
2018 ◽  
Author(s):  
Khoda N. Odedra ◽  
Saurabh Pandya ◽  
Dhaval Patel ◽  
Maheshwariba Zala

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. In this paper design and simulation of DSTATCOM with SRF Control Strategy is carried out with 3-phase 3-wire distribution system to mitigate the harmonics load current problem using MATLAB /SIMULIMK software.

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):  
Satyanarayana Gorantla ◽  
Goli Ravi Kumar

Non-linear loads connected to distribution system induce harmonics in to source components and the presence of harmonics in source components affects the performance of other sensitive loads connected at the same point. Induction motor load for drive system should be operated with variable frequency and variable voltage for its speed control. To vary the voltage and frequency, induction motor is fed from an inverter. This total drive set-up constitutes non-linear load type and will be the source of harmonics. This paper depicts the suppression of harmonics with STATCOM in distribution system when induction motor load is fed from SEIG (singly excited inductin generator). STATCOM is controlled with simple synchronous reference frame theory and the results are shown for source current, load current. THD in source current and load current was also shown for the said system. System for single-phase and three-phase induction motor drive was developed and results are shown using MATLAB/SIMULINK software.


2018 ◽  
Vol 197 ◽  
pp. 11023
Author(s):  
I Made Wiwit Kastawan

Almost all today electrical loads are considered non-linear such as switch mode power supply (SMPS) for powering computer and mobile phone or variable speed drive (VSD) for driving home and industrial electric motors. These loads generate ac non-sinusoidal current containing a lot of harmonics as indicated by its high total harmonics distortion (THD) figure. Current harmonics bring negative effects into all electrical power system components, including three-phase generator. This paper provides analysis of load current harmonics effects on vibration of three-phase generator. Three different laboratory experiments have been conducted i.e. three-phase linear resistive loading, non-linear loading with a three-phase ac/dc converter and non-linear loading with three single-phase capacitor filtered ac/dc converters. Results show that the higher load current harmonics content the higher is vibration of the three-phase generator. Non-linear loading with a three-phase ac/dc converter that generate about 24.7% THD gives an increase of 4.3% and 5.5% in average of vertical and horizontal vibrations of the three-phase generator respectively. Further, non-linear loading with three single-phase capacitor filtered ac/dc converters that generate THD as high as 74.9% gives significant increase of 28.1% and 23.6% in average of vertical and horizontal vibrations respectively.


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


Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 369
Author(s):  
Ishan Srivastava ◽  
Sunil Bhat ◽  
Agarala Ajaysekhar Reddy

Most of the power electronic components act as non-linear loads because they draw non- sinusoidal current from the power supply. Due to these non-linear loads, current harmonics are injected in the power network. For normal operation, any power network is equipped with provisions to keep the harmonics level to a minimum value. Whenever a fault occurs in the distribution system, the primary goal is to re-energize the healthy part of the network which got interrupted. It can be done by changing the topology of the network. This method is called as Service Restoration (SR). In this paper, a service restoration strategy is proposed when non-linear loads are present in the radial distribution system. Service restoration problem is formulated as a multi-objective, constrained optimization problem. Three new objectives are included to address the problem of harmonics injection by non-linear loads. Multi-Objective Particle Swarm Optimization (MOPSO) and Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) are used to find the optimal switching sequence for restoration. To test the effectiveness of the proposed methodology, IEEE 33 bus and IEEE 69 bus test systems are taken.


2015 ◽  
Vol 39 (5) ◽  
pp. 599-610 ◽  
Author(s):  
Awajiokiche Ujile ◽  
Zhengtao Ding ◽  
Haiyu Li

In the past decade, there has been a significant increase in the use of power electronic components in the design of household and industrial equipment. The use of power electronic based renewable energy resources, electric vehicles and other residential nonlinear loads may result in significant increases in injection levels of harmonics across a power system. Hence, it is important for utility companies to ascertain the exact harmonic levels present in terms of the amplitude and phase of each harmonic order. This paper provides a mathematical basis for distribution system state-space equations to formulate an iterative observer, which can simultaneously estimate harmonics present in a number of measurements taken from the power system. The method not only improves the computation time and provides real-time data for harmonic monitoring, but also performs wide area harmonic estimation for harmonic observability. Simulations and comparisons are provided to illustrate the performance of the proposed method against that obtained using a Kalman filter and fast Fourier transform (FFT). A number of scenarios such as measurement noise and change in amplitude of harmonic injections are simulated to verify the accuracy of the proposed approach and the results are included.


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.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 992
Author(s):  
Phi-Hai Trinh ◽  
Il-Yop Chung

Distributed energy resources (DERs), including renewable energy resources (RESs) and electric vehicles (EVs), have a significant impact on distribution systems because they can cause bi-directional power flow in the distribution lines. Thus, the voltage regulation and thermal limits of the distribution system to mitigate from the excessive power generation or consumption should be considered. The focus of this study is on a control strategy for DERs in low-voltage DC microgrids to minimize the operating costs and maintain the distribution voltage within the normal range based on intelligent scheduling of the charging and discharging of EVs, and to take advantage of RESs such as photovoltaic (PV) plants. By considering the time-of-use electricity rates, we also propose a 24-h sliding window to mitigate uncertainties in loads and PV plants in which the output is time-varied and the EV arrival cannot be predicted. After obtaining a request from the EV owner, the proposed optimal DER control method satisfies the state-of-charge level for their next journey. We applied the voltage sensitivity factor obtained from a load-flow analysis to effectively maintain voltage profiles for the overall DC distribution system. The performance of the proposed optimal DER control method was evaluated with case studies and by comparison with conventional methods.


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.


2013 ◽  
Vol 433-435 ◽  
pp. 1183-1187 ◽  
Author(s):  
Shao Ru Zhang ◽  
Shao Yuan Li

Renewable energy resources (RES) are being increasingly connected in distribution systems by utilizing power electronic converters. However, the extensive use of power electronics has resulted in a rise in power quality (PQ) concerns faced by the utility. A novel control strategy implementing reference compensation current was proposed in this paper. So that these grid-connected inverters can achieve maximum benefits when they installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to transfer active power from RES to the grid, and 2) load reactive power demand support; 3) current harmonics compensation at PCC; and 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. Moreover, with adequate control of grid-interfacing inverter, all the four objectives can be accomplished either individually or simultaneously. Simulation results show the validity and capability of the novel proposed control strategy.


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