Analysis of Voltage Unbalance and Energy Loss in Residential Low Voltage Distribution Systems with Rooftop Photovoltaic Systems

This paper investigates effects of voltage unbalance and energy losses due to the connection of rooftop photovoltaic systems in a low voltage distribution system of a housing estate, which has light loads during daytime. The paper presents a case study of a real distribution power system of housing estate in Thailand. Voltage unbalance and energy losses were simulated by using system characteristic and load data from GIS database of PEA with the DIgSILENT Power Factory program. The key findings of our analysis are as follows. Firstly, the number of installable 1-phase rooftop PV systems varies directly with load density. Secondly, the number of installed 1-phase rooftop PV systems can be increased if the installation locations are closer to the transformer. For 3-phase rooftop PV systems, their installations do not have any effects on the voltage unbalance. Furthermore, system energy loss relates to the load density and PV system installation locations in the same way as the voltage unbalance. The key implication of our study is that the installation of 1-phase rooftop PV system should be granted based on a careful consideration of the installation location and the load density.

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Reduction of the Low Voltage Substation Constraints by Inserting Photovoltaic Systems in Underserved Areas

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180523095219 ◽

2019 ◽

Vol 12 (2) ◽

pp. 105-112

Author(s):

Benbouza Naima ◽

Benfarhi Louiza ◽

Azoui Boubekeur

Keyword(s):

Low Voltage ◽

Voltage Drop ◽

Electrical Energy ◽

Utilization Rate ◽

Photovoltaic Systems ◽

Voltage Distribution ◽

Medium Voltage ◽

Pv Systems ◽

Transformer Substation ◽

Load Pattern

Background: The improvement of the voltage in power lines and the respect of the low voltage distribution transformer substations constraints (Transformer utilization rate and Voltage drop) are possible by several means: reinforcement of conductor sections, installation of new MV / LV substations (Medium Voltage (MV), Low Voltage (LV)), etc. Methods: Connection of mini-photovoltaic systems (PV) to the network, or to consumers in underserved areas, is a well-adopted solution to solve the problem of voltage drop and lighten the substation transformer, and at the same time provide clean electrical energy. PV systems can therefore contribute to this solution since they produce energy at the deficit site. Results: This paper presents the improvement of transformer substation constraints, supplying an end of low voltage electrical line, by inserting photovoltaic systems at underserved subscribers. Conclusion: This study is applied to a typical load pattern, specified to the consumers region.

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Hosting capacity of photovoltaic systems in low voltage distribution systems: A benchmark of deterministic and stochastic approaches

Renewable and Sustainable Energy Reviews ◽

10.1016/j.rser.2021.111899 ◽

2022 ◽

Vol 155 ◽

pp. 111899

Author(s):

Arpan Koirala ◽

Tom Van Acker ◽

Reinhilde D’hulst ◽

Dirk Van Hertem

Keyword(s):

Distribution Systems ◽

Low Voltage ◽

Photovoltaic Systems ◽

Voltage Distribution

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Performance analysis of malaysian low voltage distribution network under different solar variability days

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v13.i3.pp1152-1160 ◽

2019 ◽

Vol 13 (3) ◽

pp. 1152

Author(s):

Nur Izzati Zolkifr ◽

Chin Kim Gan ◽

Meysam Shamsiri

Keyword(s):

Low Voltage ◽

Distribution Networks ◽

Solar Variability ◽

Pv System ◽

Voltage Unbalance ◽

Pv Systems ◽

Network Losses ◽

Pv Penetration ◽

The Impact ◽

Different Levels

<span>The widespread of Photovoltaic (PV) systems as one of the distributed generation technologies could have profound impact on the distribution networks operation, particularly on network losses and network voltages fluctuations. This is mainly caused by the high PV penetrations coupled with high solar variability in the countries with large cloud cover. Therefore, this paper presents an investigation on the impact of residential grid-connected PV system by utilizing a typical low voltage (LV) network in Malaysia under various solar variability days. In this study, there are three scenarios; where, each scenario were performed with different levels of PV penetration and five different solar variability days. The impacts of PV system allocation in different scenarios and various solar variability days are assessed in term of voltage unbalance and network losses. The results propose that Scenario 1: randomly allocation of PV systems across the LV network has the lowest voltage unbalance and network losses especially during overcast day</span>

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

Energies ◽

10.3390/en13205430 ◽

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.

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Energy Loss Calculation of Low Voltage Distribution Area Based on Variational Mode Decomposition and Least Squares Support Vector Machine

Mathematical Problems in Engineering ◽

10.1155/2021/8530389 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Keyan Liu ◽

Dongli Jia ◽

Fengzhan Zhao ◽

Qicheng Zhang ◽

Shuai Hao ◽

...

Keyword(s):

Energy Loss ◽

Low Voltage ◽

Calculation Model ◽

Distribution Area ◽

Support Vector ◽

Energy Losses ◽

Variational Mode Decomposition ◽

Voltage Distribution ◽

Loss Calculation ◽

Mode Decomposition

In order to improve the accuracy of theoretical energy loss calculation in low voltage distribution area (LV-area), this paper proposes a new prediction method based on variational mode decomposition (VMD) and particle swarm optimization (PSO) least squares support vector machine (LSSVM). Firstly, the main influencing factors of energy loss calculation in LV-area are determined by the grey correlation method, which reflects the data-driven characteristic of the method and ensures the objectivity of the prediction results and the generalization of the calculation model. Secondly, the trend component and fluctuation component are obtained by VMD of daily energy loss series in the LV-area. The variable set of main influencing factors of energy losses is used as the input variable of LSSVM, and the VMD result of the energy loss sequence is used as the output. The theoretical energy loss training and calculation model of LV-area is established. Compared with the traditional calculation model, this model has more accurate calculation accuracy by taking into account the frequency characteristics of energy losses in different frequency bands. PSO is used to optimize the parameters of LSSVM for the purpose of improving the accuracy of LSSVM. Finally, an example of 252 LV-area in a city in northern China is given to verify the validity of the proposed method. The results indicate that the proposed method generates more accurate results.

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