scholarly journals Probabilistic Methodology for Calculating PV Hosting Capacity in LV Networks Using Actual Building Roof Data

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4086 ◽  
Author(s):  
Grabner ◽  
Souvent ◽  
Suljanović ◽  
Košir ◽  
Blažič
Keyword(s):  
Distribution System ◽  
Power Plants ◽  
Low Voltage ◽  
Load Flow ◽  
Major Drawback ◽  
Building Roof ◽  
Pv Systems ◽  
External Data ◽  
Increasing Trend ◽  
Pv Generation

There has been an increasing trend of integrating photovoltaic power plants (PVs). One of the important challenges for distribution system operators is to evaluate the total installed power of a PV that a particular network can host (or PV hosting capacity) while keeping voltage and element constraints within required limits. The major drawback of the existing methods for calculating PV hosting capacity is that they use the same installed power of the PV systems for all simulated PVs, as these methods do not use external data sources about building roofs. As a consequence, this has a significant impact on the final accuracy of the results. This paper presents a probabilistic methodology for calculating the PV hosting capacity in low voltage (LV) networks. The main contribution of this paper is the improved modeling of PV generation using actual building roof data when calculating the PV hosting capacity, as every building is treated according to its actual solar potential. Monte Carlo simulations with incorporated stochastic consumption and PV generation models are utilized for load flow calculations of the actual LV network. The simulation results presented in this paper prove that the proposed methodology increases the accuracy of the final PV hosting capacity calculations.

scholarly journals Sparse Measurement-Based Coordination of Electric Vehicle Charging Stations to Manage Congestions in Low Voltage Grids

Smart Cities ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 17-40
Author(s):  
Daniel-Leon Schultis
Keyword(s):  
Electric Vehicle ◽  
Distribution System ◽  
Low Voltage ◽  
Congestion Management ◽  
Load Flow ◽  
Detection Accuracy ◽  
System State ◽  
Electric Vehicle Charging ◽  
Vehicle Charging ◽  
Charging Stations

The increasing use of distributed generation and electric vehicle charging stations provokes violations of the operational limits in low voltage grids. The mitigation of voltage limit violations is addressed by Volt/var control strategies, while thermal overload is avoided by using congestion management. Congestions in low voltage grids can be managed by coordinating the active power contributions of the connected elements. As a prerequisite, the system state must be carefully observed. This study presents and investigates a method for the sparse measurement-based detection of feeder congestions that bypasses the major hurdles of distribution system state estimation. Furthermore, the developed method is used to enable congestion management by the centralized coordination of the distributed electric vehicle charging stations. Different algorithms are presented and tested by conducting load flow simulations on a real urban low voltage grid for several scenarios. Results show that the proposed method reliably detects all congestions, but in some cases, overloads are detected when none are present. A minimal detection accuracy of 73.07% is found across all simulations. The coordination algorithms react to detected congestions by reducing the power consumption of the corresponding charging stations. When properly designed, this strategy avoids congestions reliably but conservatively. Unnecessary reduction of the charging power may occur. In total, the presented solution offers an acceptable performance while requiring low implementation effort; no complex adaptations are required after grid reinforcement and expansion.

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 Incentive Price-Based Demand Response in Active Distribution Grids

2020 ◽  
Vol 11 (1) ◽  
pp. 180
Author(s):  
Karthikeyan Nainar ◽  
Jayakrishnan Radhakrishna Pillai ◽  
Birgitte Bak-Jensen
Keyword(s):  
Power Consumption ◽  
Demand Response ◽  
Distribution System ◽  
Low Voltage ◽  
Pv Systems ◽  
Home Energy Management ◽  
Demand Response Program ◽  
Battery Energy Storage Systems ◽  
Battery Energy ◽  
Distribution Grids

Integration of PV power generation systems at distribution grids, especially at low-voltage (LV) grids, brings in operational challenges for distribution system operators (DSOs). These challenges include grid over-voltages and overloading of cables during peak PV power production. Battery energy storage systems (BESS) are being installed alongside PV systems by customers for smart home energy management. This paper investigates the utilization of those BESS by DSOs for maintaining the grid voltages within limits. In this context, an incentive price based demand response (IDR) method is proposed for indirect control of charging/discharging power of the BESS according to the grid voltage conditions. It is shown that the proposed IDR method, which relies on a distributed computing application, is able to maintain the grid voltages within limits. The advantage of the proposed distributed implementation is that the DSOs can compute and communicate the incentive prices thereby encouraging customers to actively participate in the demand response program. An iterative distributed algorithm is used to compute the incentive prices of individual BESS to minimize the costs of net power consumption of the customer. The proposed IDR method is tested by conducting simulation studies on the model of a Danish LV grid for few study cases. The simulation results show that by using the proposed method for the control of BESS, node voltages are maintained within limits as well as the costs of net power consumption of BESS owners are minimized.

scholarly journals Low-Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yongheng Yang ◽  
Frede Blaabjerg
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Control Method ◽  
Low Voltage ◽  
Photovoltaic System ◽  
Pv System ◽  
Pv Systems ◽  
Low Voltage Ride Through ◽  
Three Phase ◽  
Future Challenges

The progressive growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSOs) update or revise the existing grid codes in order to guarantee the availability, quality, and reliability of the electrical system. It is expected that the future PV systems connected to the low-voltage grid will be more active with functionalities of low-voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in a low-voltage ride-through operation in order to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability with a satisfactory performance based on the grid requirements for three-phase renewable energy systems.

scholarly journals Voltage Reduction in Medium Voltage Distribution Systems Using Constant Power Factor Control of PV PCS

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5430
Author(s):  
Daisuke Iioka ◽  
Takahiro Fujii ◽  
Toshio Tanaka ◽  
Tsuyoshi Harimoto ◽  
Junpei Motoyama
Keyword(s):  
Power Factor ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Systems ◽  
Low Voltage ◽  
Voltage Distribution ◽  
Constant Power ◽  
Voltage Rise ◽  
Pv Systems ◽  
Power Factor Control

Reverse power flow from a photovoltaic (PV) system in a distribution system causes a voltage rise. A relative study regarding the reduction in the distribution feeder voltage depending on system conditions and the magnitude of reverse power flow has been conducted. Several methods for mitigating voltage rise have been proposed; however, the influence of these methods on the voltage in the distribution system, where the voltage is reduced due to reverse power flow, remains to be determined. In this study, the effect of constant power factor control in low-voltage PV systems, which are widely used as voltage rise countermeasures in distribution systems, was analyzed under the condition that the distribution line voltage decreases due to reverse power flow. Consequently, the constant power factor control of the low-voltage distribution system was found to adversely reduce voltage in the medium voltage distribution system due to the consumption of lagging reactive power by the PV systems.

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 The economic benefit analysis to the consumer and utility due to PV generation connected to the radial distribution system

2018 ◽  
Vol 7 (4) ◽  
pp. 2314
Author(s):  
G Lincy ◽  
Dr M. Ponnavaikko ◽  
Dr Lenin Anselm W. A.
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Economic Benefits ◽  
Electric Power System ◽  
System Capacity ◽  
Discounted Cash Flow ◽  
Pv System ◽  
Power Distribution System ◽  
Pv Systems ◽  
Pv Generation

During the recent past, the interest towards adoption of Distributed Generation (DG) has increased dramatically among the electric power system utilities. It has been well established that installation of PV Generation at the load points in a distribution system is excellent advantages for both consumers and the utilities. The question arises whether the maximum beneficiary is the Utility or the consumer and who has to bear the cost. This research analyses the economics of the DG with PV Systems, taking a typical 400V distribution system. A detailed procedure adopted for performing the economic analysis is presented in this paper. Benefits considered includes Saving in the energy losses, Energy substitute by the PV system, Capacity release in the Feeders and the Transformer. The PV system is installed at the selected consumer load points, based on the size and location of the loads. Discounted Cash Flow technique is used to assess the economics of the system, by computing the Internal Rate of Return. The paper presents the advantages of using PV Generating systems in the Power Distribution System, quantifying economic benefits both for the Utilities and for the Customers with supporting data.  

scholarly journals Advanced Metering Infrastructure—Towards a Reliable Network

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5986
Author(s):  
Mirosław Kornatka ◽  
Tomasz Popławski
Keyword(s):  
Distribution System ◽  
Power Plants ◽  
Low Voltage ◽  
Power Grid ◽  
Advanced Metering Infrastructure ◽  
Online Processing ◽  
Virtual Power Plants ◽  
Random Events ◽  
Advanced Metering ◽  
System Average

In order to ensure continuous energy supply, Distribution System Operators (DSOs) have to monitor and analyze the condition of the power grid, especially checking for random events, such as breakdowns or other disturbances. Still, relatively little information is available on the operation of the Low Voltage (LV) grid. This can be improved thanks to digital tools, offering online processing of data, which ultimately increases effectiveness of the power grid. Among those tools, the use of the Advanced Metering Infrastructure (AMI) is especially conducive for improving reliability. AMI is one of the elements of the system Supervisory Control and Data Acquisition (SCADA) for the LV grid. Exact knowledge of the reliability conditions of a power grid is also indispensable for optimizing investment. AMI is also key in providing operational capacity for carrying out energy balance in virtual power plants (VPPs). This paper deals with methodology of identification and location of faults in the AMI-supervised LV grid and with calculating the System Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI) on the basis of the recorded events. The results presented in the paper are based on data obtained from seven MV/LV transformer stations that supply over 2000 customers.

scholarly journals A Modification of Newton–Raphson Power Flow for Using in LV Distribution System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7600
Author(s):  
Anuwat Chanhome ◽  
Surachai Chaitusaney
Keyword(s):  
Distribution System ◽  
Power Flow ◽  
Quadratic Convergence ◽  
Low Voltage ◽  
Load Flow ◽  
Voltage Distribution ◽  
Convergence Properties ◽  
Branch Model ◽  
Power Injection ◽  
Newton Raphson

The Newton–Raphson (NR) method is still frequently applied for computing load flow (LF) due to its precision and quadratic convergence properties. To compute LF in a low voltage distribution system (LVDS) with unbalanced topologies, each branch model in the LVDS can be simplified by defining the neutral and ground voltages as zero and then using Kron’s reduction to transform into a 3 × 3 branch matrix, but this decreases accuracy. Therefore, this paper proposes a modified branch model that is also reduced into a 3 × 3 matrix but is derived from the impedances of the phase-A, -B, -C, neutral, and ground conductors together with the grounding resistances, thereby increasing the accuracy. Moreover, this paper proposes improved LF equations for unbalanced LVDS with both PQ and PV nodes. The improved LF equations are based on the polar-form power injection approach. The simulation results show the effectiveness of the modified branch model and the improved LF equations.

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