scholarly journals Power Quality and Performance Assessment of Grid-connected Photovoltaic Distributed Generation with Compliance to Stipulated Grid Integration Requirements

Author(s):  
Fredrick Nkado ◽  
Franklin Nkado

Recently, the demand for electrical energy has increased more than energy production due to the growing population and industrialization. Therefore, the distributed generators integration (DGs) into the distribution system has been widely adopted. This work examines the effect of photovoltaic-based distributed generator (PV-DG) integration on power quality effect of a radial distribution system. Firstly, the capacity and optimum placement of the PV-DG units in the distribution network are determined by employing the particle swarm optimization (PSO) algorithm. Then, the impact of PV-DG integration on voltage harmonic distortion is analyzed by performing harmonic load flow analysis. Also, the P-V curve method is used to evaluate the effects of higher PV-DG penetration levels on loading margin and voltage magnitude. The simulation results show that as the PV-DG units’ penetration level increases, a greater level of harmonic distortion is injected, implying that the PV-DG units should only be integrated up to the network’s maximum capacity. Therefore, high harmonic distortion is produced when the PV-DG units are penetrated beyond this maximum penetration level, which has a negative impact on the system’s performance. The total voltage harmonic distortion is 4.17 % and 4.24 % at PCC1 and PCC2 at the highest penetration level, allowing the acceptable harmonic distortion limit. Also, grid-connected PV-DG units improve loading margin and voltage magnitude, according to the P-V curve results. The standard IEEE-33 bus distribution system is modelled in ETAP software and is used as a test system for this study.

2021 ◽  
Vol 11 (4) ◽  
pp. 7311-7320
Author(s):  
I. C. Barutcu

Harmonic penetration can be problematic by the growing interconnection of Wind Turbines (WTs) in distribution networks. Since the active power outputs of WTs and loads in the distribution system have uncertainties, the optimal WT penetration level problem can be considered to have a stochastic nature. In this study, this problem is taken into account in the stochastic optimization method with the consideration of uncertainties in wind speed and distribution network load profile. Chance constraint programming is taken into account in the determination of optimal WT penetration levels by applying the Genetic Algorithm (GA) along with Monte Carlo Simulation (MCS). The harmonic power flow analysis based on the decoupled harmonic load flow approach is employed in the distorted distribution network. Chance constraints are considered for the harmonic issues such as the Total Harmonic Distortion of Voltage (VTHD), Individual Harmonic Distortion of Voltage (VIHDh), and Root Mean Square of Voltage (VRMS).


In this work, the Impact of integration of multiple Photo Voltaic distributed generators (PV-DGs) on power quality of the distribution system is analyzed under static and dynamic loads. Major power quality parameters considered for the analysis are voltage deviation (VD), Total Real power and reactive power line losses (PT L & QT L) and Total Harmonic Distortion of Voltage at Buses (THDv ). Test system considered for the study is the IEEE-9 bus test system and types of loads considered are Static RL and Induction motors. Modeling and simulation of test system, PVs and Induction motor loads are carriedoutinMATLAB/SIMULINK software package


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.


2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Dalila M.S. ◽  
Zaris I.M.Y. ◽  
Nasarudin A. ◽  
Faridah H.

This paper purposely to examine and analyse the impact of the distribution capacitors banks operation to the transition of total harmonic distortion (THD) level in distribution network system. The main advantage of this work is the simplicity algorithm of the method and the system being analysed using free access open software which is known as electric power distribution system simulator (OpenDSS). In this paper, the harmonic current spectrum which is collected from the commercial site was injected to a node point on IEEE13 bus in order to provide the initial measurement of THD for the network. The proper sizing of the capacitors banks has been set and being deactivated and activated throughout the network to see the transistion in the THD level in the system. The results were achieved by simulation of the data on the configured IEEE13 bus. The simulation work was done by using the combination of C++ source codes, OpenDSS and Microsoft Excel software. From the output results, the THD current has increased up to two times from the initial value in certain phases and for the THD voltage, the THD has increased up to three times from its initial value in all phases.


Author(s):  
P. Ravi Babu ◽  
Srivani Molughu

The multi objectives in electrical distribution system are service restoration and minimization of Ohmic losses. These objectives can be achieved by artificial ant colony optimization through reconfiguration. Service restoration is also a major aspect for reliable service. If any fault occurs in the system, faulted zone is isolated from healthy system. This originates discontinuity in power supply. To maintain the continuity in power supply there is a necessity to provide service to these loads from adjacent healthy feeders through reconfiguration without infringement of radiality, load balance and critical parameters. In distribution system Ohmic losses are 30 to 40 percent. In order to minimize these losses, there is a need for reconfiguration of the system and perform the power flow analysis to get bus voltages, branch currents and power losses (i.e. real or Ohmic or copper loss and reactive power loss). A direct load flow analysis is adopted in the proposed work. In this paper four feeder test system used for service restoration and IEEE 33 bus, IEEE 69 bus test systems for minimization of Ohmic losses have been obtained.


Author(s):  
Rudy Gianto ◽  
Purwoharjono Purwoharjono

This paper proposes a new and simple method to incorporate three-phase power transformer model into distribution system load flow (DSLF) analysis. The objective of the present work is to find a robust and efficient technique for modeling and integrating power transformer in the DSLF analysis. The proposed transformer model is derived based on nodal admittance matrix and formulated by using the symmetrical component theory. Load flow formulation in terms of branch currents and nodal voltages is also proposed in this paper to enable integrating the model into the DSLF analysis. Singularity that makes the calculations in forward/backward sweep (FBS) algorithm is difficult to be carried out. It can be avoided in the method. The proposed model is verified by using the standard IEEE test system.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Estifanos Abeje Sharew ◽  
Habtemariam Aberie Kefale ◽  
Yalew Gebru Werkie

The electrical energy demand is steadily growing, and hence, the integration of photovoltaic system to the distribution networks is also dramatically increasing though it has a significant effect on the network’s power quality. The purpose of this paper is to analyze the impact of solar PV integration on the power quality of distribution networks. The study is conducted using ETAP software, taking one of the radial distribution networks available in Bahir Dar city during the peak of connected loads which has the least voltage profile. Furthermore, the optimal location of the PV in the network is done using particle swarm optimization. Accordingly, the appropriate location of the PV system is determined to be the farthest end bus (bus 34). Also, the impact in terms of voltage and current harmonic distortion on the distribution feeder network is comparatively discussed by comparing the distribution system parameters with different penetration levels of solar PV system. The simulation results obtained demonstrate that high harmonic distortion level is injected correspondingly as the penetration capacity of PV system increased which indicates that the solar PV system should be integrating only up to a maximum possible capacity the network can carry. The integration of the PV system beyond this maximum penetration level causes production of high harmonic distortion which adversely affects the system performance. At the maximum penetration level which allows the acceptable harmonic distortion limit, the total voltage harmonic distortion and current demand distortion are found to be 4.97% and 14.98%, respectively.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Alma Halilović ◽  
Lejla Mujanović ◽  
Jasna Hivziefendić ◽  

The aim of this paper is to present and discuss the influence of distributed generation on power quality. Nowadays, interest in power quality has increased since it has become a very important issue in power system delivery. One of the major problems of ensuring a certain level of power quality are harmonics. The aim of this project is to investigate an impact of photovoltaic (PV) on harmonic voltage distortion (HD) in real MV distribution network. Different scenarios will be implemented where solar power plant is going to be modelled with high variability of load and generation to see their effects on the systems power quality (PQ). Those scenarios are when PV is disconnected from the grid and PVs are connected with 2 different powers. Results presented below showed that PV improves power quality of the system, because their inverters are source of harmonics and they increase HD. However, that impact is not very significant and harmonic limits are not violated. A load flow analysis is done for the model of test system 110/35/10kV in which a distributed generator is added, that is on-grid or off-grid. The network modelling and simulation is done in DIgSILENT PowerFactory software.


2017 ◽  
Vol 66 (4) ◽  
pp. 801-814 ◽  
Author(s):  
Christoph Wenge ◽  
Hui Guo ◽  
Christian Roehrig

Abstract Electric vehicles (EVs) can be utilized as mobile storages in a power system. The use of battery chargers can cause current harmonics in the supplied AC system. In order to analyze the impact of different EVs with regardto their number and their emission of current harmonics, a generic harmonic current model of EV types was built and implemented in the power system simulation tool PSS®NETOMAC. Based on the measurement data for different types of EVs three standardized harmonic EV models were developed and parametrized. Further, the identified harmonic models are used by the computation of load flow in a modeled, German power distribution system. As a benchmark, a case scenario was studied regarding a high market penetration of EVs in the year 2030 for Germany. The impact of the EV charging on the power distribution system was analyzed and evaluated with valid power quality standards.


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