Self‐consumption and storage as a way to facilitate the integration of renewable energy in low voltage distribution networks (original) (raw)
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IET Renewable Power Generation, 2018
Nowadays, a strong concern to decrease greenhouse gas emissions is encouraging the implementation of renewable energy sources closer to end-users, in low-voltage (LV) distribution networks. Due to the expected high microgeneration (µG) penetration level, several problems are likely to arise, such as overvoltages and reverse power flow. This study presents a review of the several techniques used to deal with these problems. These are compared in terms of their capacity to smooth the voltage profile and avoid reverse power flow. An unbalanced three-phase power flow algorithm, based on current summation method for radial distribution networks, is proposed. A study based on a highly unbalanced test radial LV distribution network for a typical summer day, with a high µG penetration, is performed. The voltage profile, active power flow in the service transformer, and power losses on the network are the monitored electrical quantities. The obtained results indicate that self-consumption with storage is the recommended solution to eliminate overvoltages, to avoid reverse power flow and allow for a decreasing in the power losses. Nevertheless, the economic viability of this solution must be carefully assessed, because the profitability of the project is not straightforward at the current time.
The growth of building integrated photovoltaic (BIPV) systems in low-voltage (LV) networks has the potential to raise several technical issues, including voltage unbalance and distribution system efficiency. This paper proposes an energy storage system (ESS) for mitigating voltage unbalance as well as improving the efficiency of the network. In the study, a power system simulation tool, namely PSCAD, is used to model two generic LV networks, BIPV systems and an ESS in order to simulate the performance of the networks with various levels of BIPV penetrations. A control algorithm is developed and implemented in the energy storage model in order to study the ability of the ESS to mitigate network voltage unbalance and reduce losses. Experimental studies are carried out in the experimental small-scale energy zone to investigate the effectiveness of the energy storage system under various levels of PV penetration and load conditions. The simulation and experimental studies carried out clearly show the effectiveness of the ESS in reducing the voltage unbalance factor and improving the efficiency of the two networks considered.
IEEE Transactions on Power Delivery
The growth of building integrated photovoltaic (BIPV) systems in low-voltage (LV) networks has the potential to raise several technical issues, including voltage unbalance and distribution system efficiency. This paper proposes an energy storage system (ESS) for mitigating voltage unbalance as well as improving the efficiency of the network. In the study, a power system simulation tool, namely PSCAD, is used to model two generic LV networks, BIPV systems and an ESS in order to simulate the performance of the networks with various levels of BIPV penetrations. A control algorithm is developed and implemented in the energy storage model in order to study the ability of the ESS to mitigate network voltage unbalance and reduce losses. Experimental studies are carried out in the experimental small-scale energy zone to investigate the effectiveness of the energy storage system under various levels of PV penetration and load conditions. The si mulation and experimental studies carried out cle...
22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013), 2013
This paper shows how a high penetration of PV generation in LV distribution networks can generate voltage problems, such as voltage rise and voltage unbalance. High resolution solar irradiance data from representative days is used in a network model along with real demand profiles. To reduce the voltage problems, excess power from PV sources need to be managed. A lab based battery energy storage system interfaced through a three phase power amplifier to a Real Time Digital Simulator using "power hardware in the loop" has been used to reduce the voltage problems generated by PV generation. This shows how storage is used in real time to effectively reduce voltage problems.
Introducing small storage capacity at residential PV installations to prevent overvoltages
2011 IEEE Second International Conference on Smart Grid Communications (SmartGridComm 2011), 2011
Low voltage distribution feeders are designed for unidirectional energy supply from transformer to consumer. However, the implementation of small-scale PV production units on local utilities may result in bidirectional energy flows. The simultaneous power injection at sunny moments may cause a serious voltage rise along the feeder. These overvoltages may not only damage critical loads but also switches PV inverters off causing loss of green energy at the most productive moments. This paper presents a method to limit the voltage rise by introducing small battery buffers at local production sites. A smart inverter decides whether the PV energy is injected in the grid or buffered in the batteries. The relation between battery buffer size and overvoltage reduction is presented for a typical Belgian residential distribution feeder. The influence of the buffer along the feeder is calculated by working with synthetic load profiles and solar irradiation data.
International Journal of Electrical Power & Energy Systems, 2018
This article presents an integrated storage management strategy with photovoltaic systems connected to the grid, to provide voltage regulation and losses reduction in the low voltage feeder, minimising the power supplied by the network upstream of the main transformer. A new control algorithm for battery energy storage systems (BESS) is presented embedding as a battery management algorithm for charging and discharging process. The charging of the storage system is defined by the optimization of the α k coefficient to establish the value of charging threshold power, in a distributed manner, to maximise the use of photovoltaic systems. The discharging process occurs by a given σ coefficient. A standard network model from CIGRE was used for the validation of the management strategy. It was modified with real profiles of load and irradiance with a minute resolution to adapt it to the using of the quasi-static load flow in MATLAB/Simulink. As a result, by integrating 67% of PV along with 442 kWh of BESS with its management algorithm, power import from the grid decreases up to 49.3%. Keywords-Battery management systems, energy storage, photovoltaic systems, power generation dispatch Highlights 1. The demand is evaluated by the trigonometric interpolation method. 2. A suitable control strategy optimised the BESS charging/discharging process. 3. Users depend strongly on the network reactive power. 4. Voltage and losses magnitude improve by PV+BESS penetration level.
Demand side management in the distribution system with photovoltaic generation
Tehnicki vjesnik-Technical Gazette, 2015
Original scientific paper Recently, there has been made a great effort to include electricity generation from the renewable energy sources into the power system. Random renewable generation creates the imbalance between electricity production and consumption, which requires power plants with fast response or energy storage systems. Generally accepted solution for load balancing is the concept of smart grids and one of the elements of smart grid efficiency is the ability of real-time demand-supply balancing. In this paper, the model of the part of power distribution network of the city of Osijek has been created based on results of the power measurements of total electricity consumption in a family house in Osijek, air conditioning system consumption and PV power plant production. Also, algorithm for real-time load management is proposed. It assumes coordinated control of air conditioning system units depending on the production of PV power plants and electricity consumption of distribution network, in order to reduce peak demand in the distribution network.
International Journal on Electrical Engineering and Informatics, 2020
Uncertain nature of renewable energy sources like solar irradiation poses a serious concern of loss of power supply reliability. Battery energy storage (BES) system helps in improving system reliability by storing surplus energy generated and supplying the load in case of energy deficit. Thus BES allows improvement of microgrid performance and reduces operational cost by increasing the utilization of renewable energy sources. This paper presents an energy management strategy (EMS) to dictate the power flow among photovoltaic (PV) panels, BES and the load considering a proposed time-of-use (TOU) pricing as the control factor. Its efficacy in improving power supply reliability as well as power quality issues of a 69-bus radial distribution system (RDS) is evaluated from technical performance indices like power loss, voltage deviation index and security margin and economic performance considering costs of power import from the grid and active power loss and financial benefit from batte...
Impact of renewable generation on voltage control in distribution systems
The high penetration of renewable generations in the distribution system (DS) has introduced more uncertainties and technical challenges in the operation of the grid-like voltage variation; degraded protection; altered transient stability; two-way power flow; and increased fault level. The reverse power flow due to high penetration of renewable generation may result to voltage rise which distribution network operators (DNOs) may not be able to control effectively. To that effect, this paper therefore reviews the impact of renewable generations such as solar photovoltaic (PV) and wind energy on distribution system with voltage control strategies. The work reveals that the application of smart grid technologies such as demand side integration (DSI) and energy storage (ES) mitigates voltage variation problems with minimum network reinforcement.
International Journal on Advanced Science, Engineering and Information Technology
The feed-in tariff for rooftop photovoltaic (PV) systems has not yet been adopted in Cambodia. Thus, it does not purchase excess power by reverse power flows from PV production unidirectional energy meters are used even in the capital. The power distribution systems are expanded in recent years due to load demand increase, and this issue makes the distribution system designers perform the planning. The design of a low voltage distribution system and suitable solutions are proposed to handle these issues. This paper purposes of designing an optimal low voltage distribution topology with the integration of PV and three different proposed solutions of reverse power relay (RPR), solar hybrid inverter (SHI), and battery energy storage (BES) in an urban village, which consists of improving a balanced load and existing PV production usage. Firstly, the repeated phase ABC is applied to minimize the power loss and unbalanced load in the three-phase distribution system. Next, the integration of RPR, SHI, and BES into household grid-connected PV production systems have been proposed as solutions. The urban village in Phnom Penh, Borey Mungkul Phnom Penh, Sangkat Veal Spov, is chosen and modeled for a case study to confirm a proposed method. Simulation results allow concluding that the integrated battery energy storage into the optimal low voltage distribution topology provides the best solution to design the grid connection PV system.