Study on Grid-Connected Strategy of Distribution Network with High Hydropower Penetration Rate in Isolated Operation

As the largest global renewable source, hydropower is a useful supplement to mountainous distribution networks with abundant water resources, and shoulders a large portion of the regulation duty in many power systems. In particular, in the form of decentralized energy sources located to their customers, small hydropower (SHP) improve grid stability by diversifying the electricity system and reducing power loss. The mountainous distribution networks supplied by small hydropower are closed-loop design but open-loop operation, which easily causes the tripping of tie line even further the off-grid operation of small hydropower system. Once the tie line trips, the current countermeasures—such as hydropower shutdown and load shedding—do not fully guarantee the reliability of power supply and the utilization efficiency of hydropower. This paper studies the amplitude-frequency characteristics of SHP off-grid, according to the typical integration of hydropower in South China, a SHP on-grid/off-grid model is established based on the Power Systems Computer Aided Design (PSCAD) platform. It is found that due to the inertia of SHP, the amplitude-frequency characteristics of SHP island system are relatively slow, and the process of non-synchronization with the main grid is gradually expanded. The characteristic of SHP has a certain degree of synchronization with the main grid in the initial island operates stage, which helps to find a novel grid connection method. This paper further proposes the strategy of using fast busbar automatic transfer switch (BATS), which quickly connect the trip-off SHP to the distribution network under the condition of permitting distributed energy grid-connected. The PSCAD simulation results show that proposed strategy has a limited impact on the power grid and prove the effectiveness of the method.

Download Full-text

Optimisasi Multi-objektif pada Rekonfigurasi Jaringan Distribusi Tenaga Listrik dengan Integrasi Pembangkit Terdistribusi Menggunakan Metode Sistem Kekebalan Buatan

Jurnal Teknik Elektro ◽

10.15294/jte.v12i2.26353 ◽

2020 ◽

Vol 12 (2) ◽

pp. 57-71

Author(s):

Ramadoni Syahputra ◽

Indah Soesanti

Keyword(s):

Network Optimization ◽

Load Balance ◽

Distribution Network ◽

Reducing Power ◽

Distribution Networks ◽

Operating Conditions ◽

Network Reconfiguration ◽

Multi Objective Optimization ◽

Power Losses ◽

Multi Objective

This study proposes a multi-objective optimization for power distribution network reconfiguration by integrating distributed generators using an artificial immune system (AIS) method. The most effective and inexpensive technique in reducing power losses in distribution networks is optimizing the network reconfiguration. On the other hand, small to medium scale renewable energy power plant applications are growing rapidly. These power plants are operated on-grid to a distribution network, known as distributed generation (DG). The presence of DG in this distribution network poses new challenges in distribution network operations. In this study, the distribution network optimization was carried out using the AIS method. In optimization, the goal to be achieved is not only one objective but should be multiple objectives. Multi-objective optimization aims to reduce power losses, improve the voltage profile, and maintain a maintained network load balance. The AIS method has the advantage of fast convergence and avoids local minima. To test the superiority of the AIS method, the distribution network optimization with and without DG integration was carried out for the 33-bus and 71-bus models of the IEEE standard distribution networks. The results show that the AIS method can produce better system operating conditions than before the optimization. The parameters for the success of the optimization are minimal active power losses, suitable voltage profiles, and maintained load balance. This optimization has successfully increased the efficiency of the distribution network by an average of 0.61%.

Download Full-text

Integration of Electric Vehicles in Low-Voltage Distribution Networks Considering Voltage Management

Energies ◽

10.3390/en13164125 ◽

2020 ◽

Vol 13 (16) ◽

pp. 4125

Author(s):

Miguel Carrión ◽

Rafael Zárate-Miñano ◽

Ruth Domínguez

Keyword(s):

Power Systems ◽

Electric Vehicles ◽

Power Flow ◽

Optimal Power Flow ◽

Low Voltage ◽

Distribution Network ◽

Planning Horizon ◽

Distribution Networks ◽

Mixed Integer ◽

Distribution Grid

The expected growth of the number of electric vehicles can be challenging for planning and operating power systems. In this sense, distribution networks are considered the Achilles’ heel of the process of adapting current power systems for a high presence of electric vehicles. This paper aims at deciding the maximum number of three-phase high-power charging points that can be installed in a low-voltage residential distribution grid. In order to increase the number of installed charging points, a mixed-integer formulation is proposed to model the provision of decentralized voltage support by electric vehicle chargers. This formulation is afterwards integrated into a modified AC optimal power flow formulation to characterize the steady-state operation of the distribution network during a given planning horizon. The performance of the proposed formulations have been tested in a case study based on the distribution network of La Graciosa island in Spain.

Download Full-text

Active Distribution Network Modeling for Enhancing Sustainable Power System Performance; a Case Study in Egypt

Sustainability ◽

10.3390/su12218991 ◽

2020 ◽

Vol 12 (21) ◽

pp. 8991

Author(s):

Ali A. Radwan ◽

Ahmed A. Zaki Diab ◽

Abo-Hashima M. Elsayed ◽

Hassan Haes Alhelou ◽

Pierluigi Siano

Keyword(s):

Power Systems ◽

Electricity Market ◽

System Performance ◽

Power Flow ◽

Electrical Power ◽

Distribution Network ◽

Distribution Networks ◽

Western Desert ◽

Distribution Transformers

The remarkable growth of distributed generation (DG) penetration inside electrical power systems turns the familiar passive distribution networks (PDNs) into active distribution networks (ADNs). Based on the backward/forward sweep method (BFS), a new power-flow algorithm was developed in this paper. The algorithm is flexible to handle the bidirectional flow of power that characterizes the modern ADNs. Models of the commonly used distribution network components were integrated with the developed algorithm to form a comprehensive tool. This tool is valid for modeling either balanced or unbalanced ADNs with an unlimited number of nodes or laterals. The integrated models involve modeling of distribution lines, losses inside distribution transformers, automatic voltage regulators (AVRs), DG units, shunt capacitor banks (SCBs) and different load models. To verify its validity, the presented algorithm was first applied to the unbalanced IEEE 37-node standard feeder in both passive and active states. Moreover, the algorithm was then applied to a balanced 22 kV real distribution network as a case study. The selected network is located in a remote area in the western desert of Upper Egypt, far away from the Egyptian unified national grid. Accordingly, the paper examines the current and future situation of the Egyptian electricity market. Comparison studies between the performance of the proposed ADNs and the classical PDNs are discussed. Simulation results are presented to demonstrate the effectiveness of the proposed ADNs in preserving the network assets, improving the system performance and minimizing the power losses.

Download Full-text

Comprehensive Evaluation of Smart Grid Development Level Under Electricity Market Layout

E3S Web of Conferences ◽

10.1051/e3sconf/20185302013 ◽

2018 ◽

Vol 53 ◽

pp. 02013 ◽

Cited By ~ 1

Author(s):

Zhe Chen ◽

Haiyun An ◽

Ze Sun ◽

Bingcheng Cen ◽

Si Li

Keyword(s):

Smart Grid ◽

Power Systems ◽

Electricity Market ◽

Comprehensive Evaluation ◽

Evaluation Model ◽

Distribution Network ◽

Distribution Networks ◽

Evaluation Index System ◽

System Reform ◽

Development Level

The smart grid is the latest trend and complex scientific issue in the development of power systems in the world today. With the new round of power system reform and the deregulation of the power market, comprehensive and scientific evaluation of the development level of the smart grid plays an important role in achieving the overall goal of smart grid construction. This paper constructed a comprehensive evaluation index system from the aspects of safety and reliability, economy, intelligence level and sustainability of smart distribution network. Then the comprehensive evaluation model of AHPTOPSIS intelligent distribution network was established. Finally, an empirical study on the development level of smart distribution networks of four power companies in a province was carried out, and corresponding conclusions were drawn.

Download Full-text

Two States for Optimal Position and Capacity of Distributed Generators Considering Network Reconfiguration for Power Loss Minimization Based on Runner Root Algorithm

Energies ◽

10.3390/en12010106 ◽

2018 ◽

Vol 12 (1) ◽

pp. 106 ◽

Cited By ~ 11

Author(s):

Anh Viet Truong ◽

Trieu Ngoc Ton ◽

Thuan Thanh Nguyen ◽

Thanh Duong

Keyword(s):

Power Loss ◽

Distribution Network ◽

Distribution Networks ◽

Open Loop ◽

Network Reconfiguration ◽

Optimal Position ◽

Distributed Generator ◽

Operational Problem ◽

The Status ◽

Calculation Results

Although the distributed generator (DG) placement and distribution network (DN) reconfiguration techniques contribute to reduce power loss, obviously the former is a design problem which is used for a long-term purpose while the latter is an operational problem which is used for a short-term purpose. In this situation, the optimal value of the position and capacity of DGs is a value which must be not affected by changing the operational configuration due to easy changes in the status of switches compared with changes in the installed location of DG. This paper demonstrates a methodology for choosing the position and size of DGs on the DN that takes into account re-switching the status of switches on distribution of the DN to reduce power losses. The proposed method is based on the runner root algorithm (RRA) which separates the problem into two states. In State-I, RRA is used to optimize the position and size of DGs on closed-loop distribution networks which is a mesh shape topology and power is delivered through more than one line. In State-II, RRA is used to reconfigure the DN after placing the DGs to find the open-loop distribution network which is a tree shape topology and power is only delivered through one line. The calculation results in DN systems with 33 nodes and 69 nodes, showing that the proposed method is capable of solving the problem of the optimal position and size of DGs considering distribution network reconfiguration.

Download Full-text

Optimal Site and Size of Distributed Generator in Distribution Network Considering Active Power Loss Minimization

Quaid-e-Awam University Research Journal of Engineering, Science & Technology ◽

10.52584/18.2.2 ◽

2020 ◽

Vol 18 (02) ◽

pp. 11-20

Author(s):

Aamir Ali ◽

M. Usman Keerio ◽

Noor Hussain Mugheri ◽

Munawar Ayaz Memon ◽

Erum Pathan

Keyword(s):

Distribution System ◽

Distribution Network ◽

Reducing Power ◽

Distribution Networks ◽

Optimal Choice ◽

Optimal Decision ◽

Optimization Approach ◽

Solar Pv ◽

Power Losses ◽

Optimal Site

Distributed Generation (DG) allocation in distribution network is an optimal choice in maximizing benefits and reducing power losses. In this paper, self-adaptive differential evolution (SaDE), an optimization approach, is used for optimal site and capacity of DG. Different types of DGs such as solar PV and wind turbine (WT) at constant and near unity power factor are integrated into the distribution system. For validation of the proposed algorithm, IEEE 33-bus, 69-bus and 119-bus radial distribution networks are considered. The results show that the proposed algorithm has the ability to find global minimum value of objective function along with the appropriate site and capacity of solar PV and WT type DG. Moreover, the results of proposed method are compared with other existing techniques in order to show its effectiveness. The comparison shows that the proposed technique has the ability to get the lowest power losses with the smallest DG size. Thus, the proposed technique has the ability to find an optimal decision vector that makes it suitable for real-time applications.

Download Full-text

Optimal Site and Size of Distributed Generator in Distribution Network Considering Active Power Loss Minimization

Quaid-e-Awam University Research Journal of Engineering, Science & Technology ◽

10.52584/qrj.1802.02 ◽

2020 ◽

Vol 18 (02) ◽

pp. 11-20

Author(s):

Aamir Ali ◽

M. Usman Keerio ◽

Noor Hussain Mugheri ◽

Munawar Ayaz Memon ◽

Erum Pathan

Keyword(s):

Distribution System ◽

Distribution Network ◽

Reducing Power ◽

Distribution Networks ◽

Optimal Choice ◽

Optimal Decision ◽

Optimization Approach ◽

Solar Pv ◽

Power Losses ◽

Optimal Site

Download Full-text

Automatic Overcurrent Protection Coordination after Distribution Network Reconfiguration Based on Peer-To-Peer Communication

Energies ◽

10.3390/en14113253 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3253

Author(s):

Alex Valenzuela ◽

Silvio Simani ◽

Esteban Inga

Keyword(s):

Power Systems ◽

Electrical Power ◽

Distribution Network ◽

Distribution Networks ◽

Peer To Peer ◽

Electrical Power Systems ◽

Correct Operation ◽

The Status ◽

Remedial Actions ◽

Current Setting

Electrical power systems represent a fundamental part of society, and their efficient operations are of vital importance for social and economic development. Power systems have been designed to withstand interruptions under already provided safety and quality principles; however, there are some extreme and not so frequent events that could represent inconveniences for the correct operation of the entire system. For this reason, in recent years the term resilience, which serves to describe the capacity of a system to recover from an unwanted event, has been analyzed on planning, operation and remedial actions. This work is focused on the implementation of a topological reconfiguration tool, which is oriented to change the structure of primary feeders based on changing the status of switchgears. Once the distribution network has been reconfigured, an algorithm of protection coordination is executed based on communication peer-to-peer between Matlab and PowerFactory, which develops an adaptive calculation to determine the current setting and the time multiplier setting. The reconfiguration and coordination protection algorithms could be implemented and evaluated on different distribution networks, areas and locations.

Download Full-text

Modeling of Lightning Strike Events, and it’s Correlational with Power Outages in South-West Coast, Nigeria

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v7i6.pp3262-3270 ◽

2017 ◽

Vol 7 (6) ◽

pp. 3262 ◽

Cited By ~ 1

Author(s):

Melodi A. O. A. O. ◽

Olayinka Matthew Oyeleye

Keyword(s):

Power Systems ◽

Power Distribution ◽

Distribution System ◽

Distribution Network ◽

Distribution Networks ◽

Lightning Strike ◽

Power Outages ◽

Lightning Strikes ◽

Power Distribution System ◽

Review Management

This paper aimed to model lightning strike events and evaluate its correlation with power outages in a Nigerian power distribution system. A specified coastal distribution network of southwest Nigeria was selected as a case study. Zone-specific records of cloud-to-ground lightning strikes for 84 months were obtained from the Nigerian Meteorological Agency (NiMet); records of power outage frequencies and durations for 36 months were obtained at the substations of the selected distribution network. Using numerical statistical analysis techniques, lightning activity in the system area were characterized in relative frequency terms, and correlation statistics were evaluated and analyzed for power outages and lightning events on the 11kV, 33kV, and 132kV voltage levels. An analysis of the results shows that the modelled lightning strike events patterns are closely related but the expected frequencies vary from one zone to another; and there is correlation between lightning strike and power outages in the distribution networks, which is strong and positive at the 33 kV and 132 kV circuits. In essence, the results provided salient information, useful for power systems lightning protection review, management and planning in the area.

Download Full-text

Multivariable control of active distribution networks for TSO-DSO-coordinated operation in wide-area power systems

at - Automatisierungstechnik ◽

10.1515/auto-2019-0066 ◽

2019 ◽

Vol 67 (11) ◽

pp. 904-911

Author(s):

Holm Hinners ◽

Daniel Mayorga Gonzalez ◽

Johanna Myrzik ◽

Christian Rehtanz

Keyword(s):

Power Systems ◽

Power Plants ◽

Reactive Power ◽

Multiple Input Multiple Output ◽

Distribution Network ◽

Distribution Networks ◽

Transmission Network ◽

Voltage Profile ◽

Distribution Grid ◽

Control Concept

Abstract This paper describes a multiple-input, multiple-output distributed control concept for the operation of a distribution network. The concept aims to coordinate a set of distributed generators within the distribution grid to regulate the active and reactive power flow exchange with the transmission network and adjacent distribution grids. The control concept further aims to control the distribution network voltage profile such that voltages continuously remain within a predefined secure operation range. The implementation of such a concept can substitute for the decreasing flexibility in the transmission network which results from the decommissioning of conventional power plants in the future. As proof-of-concept, an implementation is tested through time-domain simulation.

Download Full-text