scholarly journals Gaussian Copula Methodology to Model Photovoltaic Generation Uncertainty Correlation in Power Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2349
Author(s):  
Harshavardhan Palahalli ◽  
Paolo Maffezzoni ◽  
Giambattista Gruosso
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Low Voltage ◽  
Distribution Networks ◽  
Load Flow ◽  
Power Grids ◽  
Gaussian Copula ◽  
Expansion Planning ◽  
Probabilistic Load Flow ◽  
Photovoltaic Generators

Deterministic load flow analyses of power grids do not include the uncertain factors that affect the network elements; hence, their predictions can be very unreliable for distribution system operators and for the decision makers who deal with the expansion planning of the power network. Adding uncertain probability parameters in the deterministic load flow is vital to capture the wide variability of the currents and voltages. This is achieved by probabilistic load flow studies. Photovoltaic systems represent a remarkable source of uncertainty in the distribution network. In this study, we used a Gaussian copula to model the uncertainty in correlated photovoltaic generators. Correlations among photovoltaic generators were also included by exploiting the Gaussian copula technique. The large sets of samples generated with a statistical method (Gaussian copula) were used as the inputs for Monte Carlo simulations. The proposed methodologies were tested on two different networks, i.e., the 13 node IEEE test feeder and the non-synthetic European low voltage test network. Node voltage uncertainty and network health, measured by the percentage voltage unbalance factor, were investigated. The importance of including correlations among photovoltaic generators is discussed.

scholarly journals Optimal Integration of Distributed Generation in Distribution System: A Case Study of Sallaghari Feeder from Thimi Switching Station, Bhaktapur, Nepal

2020 ◽  
Vol 15 (1) ◽  
pp. 242-249
Author(s):  
Basanta Pancha ◽  
Rajendra Shrestha ◽  
Ajay Kumar Jha
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Power Loss ◽  
Low Voltage ◽  
Test System ◽  
Load Flow ◽  
Voltage Profile ◽  
Alternative Source ◽  
Load Demand ◽  
Higher Power

 The modern power distribution network is constantly being faced with an ever-growing load demand resulting into increased burden and reduced voltage, which leads to find alternative source of energy to meet it. In Nepal, the electricity supply is based on hydropower primarily, which are situated very far from load centers and hence the generated power are to be transmitted through transmission and distributed system. Among the systems, radial distribution system is popular because of low cost and simple design, but it has power quality issues like low voltage profile and higher loss. In response to the problem of increased load demand, efforts have been made to decentralize this infrastructure through the use of distributed generators. However, the improper sizing and placement of DG unit may lead to higher power loss and power instability. The optimization problem of DG unit placement and its capacity determination were performed in this research. The study has been carried out for Thimi-Sallaghari Feeder and this feeder has low voltage profile and higher power loss. The IEEE 33 bus test system was examined as a test case to demonstrate the effectiveness of the proposed approach. The study has been carried out in MATLAB using “Backward and Forward Sweep Method” for load flow analysis and Genetic Algorithm for optimization. The number of DG unit of different size integrated was varied from one to ten. The result of this study showed that the voltage at minimum voltage node, maximum active and reactive loss reduction of Thimi-Sallaghari feeder have been improved by 3.69% (from 0.942 p.u. to 0.976 p.u), 75.88 % and 75.88 % respectively with placement of DG units at three bus locations of total 658.2019 kW and 395.873 kVAR capacity. Likewise, the voltage at minimum voltage node, maximum active and reactive loss of IEEE- 33 bus system have been improved by 6.88 %, 90.11% and 89.9% respectively with placement of DG units of total 2215.488 kW and 1176.059 kVAR at 6 different locations of the network.  

scholarly journals On the Conflict between LVRT and Line Protection in LV Distribution Systems with PVs: A Current-Limitation-Based Solution

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2909 ◽  
Author(s):  
Aristotelis Tsimtsios ◽  
Dionisis Voglitsis ◽  
Ioannis Perpinias ◽  
Christos Korkas ◽  
Nick Papanikolaou
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Energy Resource ◽  
Distribution Networks ◽  
Voltage Distribution ◽  
Current Limitation ◽  
Protection Scheme ◽  
Low Voltage Ride Through ◽  
Photovoltaic Generators

The upcoming adoption of low-voltage-ride-through requirements in low-voltage distribution systems is expected to raise significant challenges in the operation of grid-tied inverters. Typically, these inverters interconnect photovoltaic units, which are the predominant distributed energy resource in low-voltage distribution networks, under an umbrella of standards and protection schemes. As such, a challenging issue that should be considered in low-voltage distribution network applications, regards the coordination between the line protection scheme (typically consisting of a non-settable fuse) and the low-voltage-ride-through operation of photovoltaic generators. During a fault, the fuse protecting a low-voltage feeder may melt, letting the generator to continue its ride-through operation. Considering that the efficacy/speed of the anti-islanding detection is affected by ride-through requirements, this situation can lead to protracted energization of the isolated feeder after fuse melting (unintentional islanding). To address this issue, this paper proposes a fault-current-limitation based solution, which does not require any modification in the existing protection scheme. The operation principles, design, and implementation of this solution are presented, while, its effectiveness is supported by extensive simulations in a test-case low-voltage distribution system. A discussion on the presented results concludes the paper.

scholarly journals A Novel Algorithm with Multiple Consumer Demand Response Priorities in Residential Unbalanced LV Electricity Distribution Networks

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1220
Author(s):  
Ovidiu Ivanov ◽  
Samiran Chattopadhyay ◽  
Soumya Banerjee ◽  
Bogdan-Constantin Neagu ◽  
Gheorghe Grigoras ◽  
...  
Keyword(s):  
Demand Response ◽  
Distribution System ◽  
Smart Grids ◽  
Low Voltage ◽  
Distribution Networks ◽  
Load Flow ◽  
Electricity Distribution ◽  
Energy Management Systems ◽  
Home Energy Management ◽  
Novel Algorithm

Demand Side Management (DSM) is becoming necessary in residential electricity distribution networks where local electricity trading is implemented. Amongst the DSM tools, Demand Response (DR) is used to engage the consumers in the market by voluntary disconnection of high consumption receptors at peak demand hours. As a part of the transition to Smart Grids, there is a high interest in DR applications for residential consumers connected in intelligent grids which allow remote controlling of receptors by electricity distribution system operators and Home Energy Management Systems (HEMS) at consumer homes. This paper proposes a novel algorithm for multi-objective DR optimization in low voltage distribution networks with unbalanced loads, that takes into account individual consumer comfort settings and several technical objectives for the network operator. Phase load balancing, two approaches for minimum comfort disturbance of consumers and two alternatives for network loss reduction are proposed as objectives for DR. An original and faster method of replacing load flow calculations in the evaluation of the feasible solutions is proposed. A case study demonstrates the capabilities of the algorithm.

scholarly journals Voltage Stability of Low-Voltage Distribution Grid with High Penetration of Photovoltaic Power Units

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1960 ◽  
Author(s):  
Majid Ghaffarianfar ◽  
Amin Hajizadeh
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Voltage Stability ◽  
Low Voltage ◽  
Distribution Networks ◽  
High Ratio ◽  
Distribution Grid ◽  
Negative Effects ◽  
Loss Analysis

Voltage stability analysis of power distribution systems with high photovoltaic (PV) penetration is a challenging problem due to the stochastic generation of a solar power system. Voltage stability is an important benchmark for defining PV’s penetration level in active distribution networks considering loading capacity. The massive integration of PV power units, the effect of distribution system characteristics, like high ratio of R/X, and the reported collapses in power networks come up in serious studies that investigate their impact and upcoming problems on distribution networks. Therefore, this paper proposes analytical voltage stability and it is implemented on IEEE 34 nodes radial distribution systems with 24.9 kV and 4.16 kV voltage levels. In this regard, in addition to given properties in stability and power loss analysis, a penetration coefficient for PVs is considered. Simulation results prove that the applied method can illustrate the positive and negative effects of PV in distribution networks.

Sign in / Sign up

Export Citation Format

Share Document