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Distributed solar photovoltaic (PV) generation market continues to grow with increasing operational challenges for distribution network operators. In South Africa, residential solar PV system projects have also been implemented in low voltage distribution networks, and there are plans for future projects at municipal level. Residential solar PV growth introduces more technical and economic concerns...
In the era of smart grid, the demand for power system security is further urgent. Two-terminal electromagnetic loop networks (two-terminal EMLNs) are pervasive in power networks. Their potential hazard threatens the safety of both power network and users. Due to the influence of the power flow on the high voltage side of the EMLN, the power flow on the low voltage side tends to operate at a critical...
The increased integration of PV systems in the low voltage network causes many problems in network operations. The EU project STORY is tackling these problems with adding energy storage to the grid. In this paper we present new control concept with peak demand control algorithm which is used on storage unit in LV distribution network. The algorithm development is based on real measurements from transformer...
In this investigation, some strategies are presented for the optimized provision of reactive power by photovoltaic (PV) systems to perform voltage regulation in a low voltage distribution grid. The optimization is based on an optimal power flow algorithm that determines the minimum amount of reactive power needed for voltage regulation, also resulting in the minimization of losses in the network....
Installation of single-phase rooftop photovoltaic (PV) systems in low voltage (LV) residential feeders without controlling their ratings and locations may deteriorate the overall grid performance including reversed power flows, high losses and unacceptable voltage profiles. Therefore, in recent years the utilities have adopted limitations on the maximum allowable number of PVs in LV networks. To overcome...
The ongoing trend to sustainable energy supply based on renewable energies is coming along with new challenges in network control. Especially in the low voltage distribution networks, new control structures are required, since they have been considered as a passive system in regards of network control. As a feasible solution for structuring power networks the Clustering Power System Approach (CPSA)...
Utilization of rooftop photovoltaic cells (PVs) in residential feeders without controlling their ratings and locations may deteriorate the overall grid performance including power flows, losses and voltage profiles. This paper investigates different methods for regulating the voltage profile and reducing the voltage unbalance at low voltage residential feeders. The algorithm considers reactive power...
For Inductive Power Transfer (IPT) system, the bi-directional power transfer mode is designed for energy feedback from receiver to transmitter. It will be helpful to improve system efficiency in high power application. In order to realize power flow from low voltage side to high voltage side, the paper gives voltage gain analysis method. On the basis, aiming at the power flow control, the paper proposes...
This contribution proposes a method to analyze the capabilities of low voltage grids to meet the demands of additional loads due to electric mobility. Probabilistic load models for both the domestic and electric vehicle loads are developed to give insight into the stochastic nature of load distribution and voltage bands. The results not only provide the maximum voltage deviations, but their probability...
Photovoltaic (PV) electric power generation may be a significant grid resource in the future. As such, there is an industry need for appropriate models for transmission and/or distribution planning studies. This paper describes the latest positive sequence, fundamental frequency models of GE solar PV plants. The model is as detailed as is appropriate for bulk power system studies, where the analysis...
The performance of distribution transformers serving several residential networks with multiple Plug-In Electric Vehicle (PEV) charging activity is studied in this paper. Distribution transformers are the weakest link in distribution systems that could soon be subjected to increasing stresses from PEV charging activity. This could significantly impact the reliability, security, efficiency and economy...
The quality of the voltage levels in permanent regime demands an optimized electric system, with control of equipments and of the voltage profile in the several load patterns. The allocation and configuration of voltage regulators and capacitor banks become complex tasks, because it is a problem of combinatorial analysis with whole-mixed variables and non-lineal restrictions. With the objective of...
The paper deals with the analysis of a low voltage dc distribution system. This dc system efficiently uses the opportunities that distribution generators (DG) offers for the power quality improvement, considering the more easily interconnection of the energy storage devices. The analysis of the energy management system and the behavior of the dc system during faults in the ac grid and dc grid are...
The necessity to ensure premium power quality to the sensitive customers and development of distributed generators (DG), have determined the consideration of realizing a low voltage DC distribution system. This low voltage DC distribution system will represent a premium power network that combines the advantages of the equipments used for improving the voltage quality and supply continuity, and uses...
This paper describes a study aiming at build of back to back (BTB) system for the test of high power DC-DC Converter. The proposed new BTB system for test circuit offers the solutions in the reduction of the capability of input power source and bidirectional operational mode test at rating condition. This time we built 20 kW BTB system actually and tested it by 100 kW DC-DC converter. We report the...
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