Operation and planning of distribution networks with integration of renewable distributed generators considering uncertainties: a review

YesDistributed generators (DGs) are a reliable solution to supply economic and reliable electricity to customers. It is the last stage in delivery of electric power which can be defined as an electric power source connected directly to the distribution network or on the customer site. It is necessary to allocate DGs optimally (size, placement and the type) to obtain commercial, technical, environmental and regulatory advantages of power systems. In this context, a comprehensive literature review of uncertainty modeling methods used for modeling uncertain parameters related to renewable DGs as well as methodologies used for the planning and operation of DGs integration into distribution network.This work was supported in part by the SITARA project funded by the British Council and the Department for Business, Innovation and Skills, UK and in part by the University of Bradford, UK under the CCIP grant 66052/000000

Voltage stability maximization based optimal network reconfiguration in distribution networks using integrated particle swarm optimization for marine power applications

1949-1956This paper addresses a novel method to optimize network reconfiguration problem in radial distribution network considering voltage stability maximization and power loss reduction without violating the system constraints. In nature inspired population based standard particle swarm optimization (PSO) technique, the flight path of current particle depends upon global best and particle best position. However, if the particle flies nearby to either of these positions, the guiding rule highly decreases and even vanishes. To resolve this problem and to find the global best position, integrated particle swarm optimization (IPSO) is utilized for finding the optimal reconfiguration in the radial distribution network. The performance and effectiveness of the method are validated through IEEE 33 and 69 buses distribution networks and is compared with other optimization techniques published in recent literature for optimizing network reconfiguration problem. The simulated results simulate the fact that to attain the global optima, IPSO requires less numbers of iterations as compared to the simple PSO. The present method facilitates the optimization of modern electric power systems by empowering them with voltage stability

Simultaneous optimal placement and sizing of DSTATCOM and parallel capacitors in distribution networks using multi-objective PSO

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The increase in electricity demands has increased the dimension and loading of today radial distribution feeders, which in turn would result in more losses and voltage drops. Such issues together with the demand for higher power quality has raised a need for modern power system management techniques such as using power electronic devices. Among, DSTATCOM is introduced as an effective solution for reactive power control in power distribution level. To make a better use of DSTATCOM in improving the network power quality, it should be sized and placed in accordance with parallel capacitors. A multi-objective optimization method is proposed in this paper to find the optimal location and size of DSTATCOM and parallel capacitors simultaneously. The cost of power losses, voltage profile and voltage stability are selected as objectives to be improved. The obtained results on the IEEE 33-node test system indicate that the proposed method satisfies the defined objectives and considerably improves the network operational characteristics

Optimal Reconfiguration and Capacitor Allocation in Radial Distribution Systems Using the Hybrid Shuffled Frog Leaping Algorithm in the Fuzzy Framework

In distribution systems, in order to diminish power losses and keep voltage profiles within acceptable limits, network reconfiguration and capacitor placement are commonly used. In this paper, the Hybrid Shuffled Frog Leaping Algorithm (HSFLA) is used to optimize balanced and unbalanced radial distribution systems by means of a network reconfiguration and capacitor placement. High accuracy and fast convergence are the highlighted points of the proposed approach because of solving the multi-objective reconfiguration and capacitor placement in fuzzy frame work. These objectives are the minimization of total network real power losses, the minimization of buses voltage violation, and load balancing in the feeders. Each objective is transferred into fuzzy domain using membership function and fuzzified separately. Then, the overall fuzzy satisfaction function is formed and considered as a fitness function. To gain the optimal solution, the value of this function will be maximized. In the literature, several reconfiguration and capacitor placement methods have been investigated, which are implemented separately. However, there are few studies which simultaneously apply these two strategies. The proposed algorithm has been implemented in three IEEE test systems (two balanced and one unbalanced systems). Numerical results obtained by simulation show that the performance of the HSFLA algorithm is much higher than several other meta-heuristic algorithms

Loss allocation in distribution networks with distributed generators undergoing network reconfiguration

In this paper, a branch exchange based heuristic network reconfiguration method is proposed for obtaining an optimal network in a deregulated power system. A unique bus identification scheme is employed which makes the load flow and loss calculation faster due to its reduced search time under varying network topological environment. The proposed power loss allocation technique eliminates the effect of cross-term analytically from the loss formulation without any assumptions and approximations. The effectiveness of the proposed reconfiguration and loss allocation methods are investigated by comparing the results obtained by the present approach with that of the existing “Quadratic method” using a 33-bus radial distribution system with/without DGs

Identifikasi dan Peningkatan Nilai Stabilitas Tegangan pada Sistem Distribusi Tiga Fasa Menggunakan Metode Positive Sequence Catastrophe Theory

Permasalahan stabilitas tegangan pada sistem distribusi ditandai dengan penurunan tegangan secara cepat yang diakibatkan oleh pembebanan sistem yang berlebih. Penurunan nilai stabilitas tegangan pada sistem distribusi akan mengakibatkan jumlah beban yang dapat tersuplai menjadi terbatas. Terlebih lagi sistem distribusi yang terbuhung langsung ke beban mengakibatkan permasalahan stabilitas tegangan pada sistem distribusi menjadi sebuah permasalahan serius. Dampak terburuk dari permasalahan stabilitas tegangan adalah menyebabkan sistem menjadi padam total. Dengan melihat nilai indeks stabilitas tegangan (VSI), menggunakan metode L-index atau catastrophe theory kondisi stabilitas tegangan pada sebuah sistem distribusi dapat diketahui. Namun, teknik-teknik tersebut menggunakan pendekatan sistem distribusi yang dianggap seimbang. Untuk itu didalam disertasi ini dikembangkan sebuah metode untuk mencari nilai indeks stabilitas tegangan pada sistem distribusi tiga fasa tak seimbang. Metode ini merupakan pengembangan konsep sequence component. Sequence component digunakan untuk menyederhanakan analisis sistem tenaga listrik yang tidak seimbang menjadi komponen urutan positif, negatif dan nol. Nilai sequence component inilah yang akan digunakan pada metode Catastrophe Theory untuk menentukan nilai indeks stabilitas tengangan pada sistem distribusi tiga fasa tidak seimbang. Metode ini bernama metode Positive Sequence Based Catastrophe Theory Voltage Stability Index (P.S Cat VSI). Kemudian hasil metode ini dibandingkan dengan nilai urutan indeks stabilitas tegangan hasil dari nilai positive sequence Voltage Ranking Index (VRI) dan Voltage Stability Index (VSI’s) tiga fasa untuk validasi metode usulan, sedangkan plant yang digunakan adalah IEEE radial 15 bus dan sistem distribusi surabaya utara 20 kV. Nilai indeks stabilitas tegangan yang diperoleh dari metode usulan akan menjadi dasar untuk melakukan peningkatan nilai stabilitas tegangan. Pada akhir penelitian ini diperoleh mekanisme untuk mengatasi permasalahan stabilitas tegangan yang dapat diimplementasikan kedalam sebuah sistem distribusi sehingga diperoleh sebuah otomasi sistem distribusi (distribution automation system) pada sistem distribusi tidak seimbang. ================================================================================================================== Voltage stability problems in the distribution system is characterized by rapid voltage drop caused by excessive loading system. Impairment of voltage stability in the distribution system will result in the amount of load that can be supplied is limited. Moreover, the distribution system directly connected to the load lead the voltage stability problems in the distribution system becomes a serious problem. The worst effects of voltage stability problem is causing the system blackout. By looking at the voltage stability index (VSI) value, L-index and catastrophe theory, the voltage stability condition in a distribution system can be observed. However, these techniques use a balanced approach to the distribution system. In this dissertation developed a new method to obtain the value of voltage stability index in three-phase unbalanced distribution system. The proposed method is a development of the symmetrical components. Symmetrical components is used to simplify analysis of unbalanced distribution system by changing the phase value into positive, negative and zero sequences. The value of the sequence will be used in Catastrophe Theory method to determine the value of voltage stability index on three phase unbalanced distribution system. This method called positive sequence based catastrophe theory voltage stability index (P.S Cat VSI). Then the results of the proposed method will be compared with the value of the positive sequence voltage ranking and VSIs three phase to validate the proposed method, while the plant used are IEEE 15 bus radial distribution systems and Surabaya Utara 20 kV distribution systems. Voltage stability index values obtained from the proposed method used as a reference to improve voltage stability index values in unbalanced distribution system. In this dissertation obtained a mechanism to prevent voltage stability problems that can be implemented on the distribution automation system for unbalanced distribution systems

Optimal operation of hybrid AC/DC microgrids under uncertainty of renewable energy resources : A comprehensive review

The hybrid AC/DC microgrids have become considerably popular as they are reliable, accessible and robust. They are utilized for solving environmental, economic, operational and power-related political issues. Having this increased necessity taken into consideration, this paper performs a comprehensive review of the fundamentals of hybrid AC/DC microgrids and describes their components. Mathematical models and valid comparisons among different renewable energy sources’ generations are discussed. Subsequently, various operational zones, control and optimization methods, power flow calculations in the presence of uncertainties related to renewable energy resources are reviewed.fi=vertaisarvioitu|en=peerReviewed

Distribution power loss minimization via optimal sizing and placement of shunt capacitor and distributed generator with network reconfiguration

The population is speeding up and the demands for electrical energy are clearly increasing, this growth in load leads to higher power loss and Voltage drop. This paper is focused on a method to decrease the power losses and voltage profile improvement. The first suggested technique binary particle swarm optimization BPSO is utilized for solving the problem of the power loss minimization in network distribution. This work based on optimum position and sizing of the distribution generation (DG) units, shunt capacitor (SC) with network reconfiguration is applied to show the improvement of the network distribution efficiency. The MATLAB programming part and software package MATPOWER7 are used to simulate 69-bus and 33-bus test system with three different cases of loads and different number of DG and SC. The result showed a positive impact on system efficiency in comparison with other previous studies. This paper showed that increase of DG and capacitor does not usually give the best result although the increase of system cost, maintenance, and the units' distance for gas supplying