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The rapid increase in installed distributed generation (DG) has led to concerns about the impact on the proper operation of the protection system. In particular, the limited fault current capability of inverter interfaced distributed generation (IIDG) could lead to malfunctioning of the distribution network protection system which largely relies on overcurrent based protection techniques. The absence...
This paper presents an infrastructure and laboratory implementation of a hardware test-bed system emulating alternate sources and conventional power plant emulators connected as a complete power system. The distributed generation components were connected to the test-bed to study the issues of connecting alternates and various types of loads during operations. The various sources and loads can be...
Economic, technology and environmental incentives are changing the features of electricity generation and transmission. Centralized power systems are giving way to local scale distributed generations. At present, there is a need to assess the effects of large numbers of distributed generators and short-term storage in Microgrid. To accommodate the high demand of renewable energy and the environment...
The connection of generating sources in the distribution systems is on the increase worldwide. If on one hand this practice brings well-known benefits for the system, on the other, there are several institutional barriers that make difficult its feasibility. This way, the Brazilian National Electric Energy Agency (ANEEL) has developed the so called “Distribution Procedures”, which is a set of rules...
We propose two optimization-based models for computing the allowable penetration level of multiple distributed generators, taking into account voltage regulation constraints. A single level optimization model is developed for computing the maximum penetration level, while a bi-level optimization model is developed to answer the question as to at least how much power a distribution system can accommodate...
This paper presents real time test results arising from the application of a case based reasoning technique for voltage control of a section of existing UK 11kV network. The test network includes two distributed generation schemes. The objective of the case based reasoning technique is to maintain voltages within statutory limits while also maximizing the DG access to the network. The control algorithm...
High levels of distributed generation have been installed in power systems and even a greater amount is expected to be deployed in the near future, with a large percentage likely to come from renewable energy sources. As such, Distribution System Operators (DNOs) will need to change their old “business as usual” passive approach, to one that adopts integration of control and communication technologies,...
This paper discusses the connection policies adopted to facilitate the large number of wind farms seeking access to the Irish power system. A key feature is a grouped connection offer process that provides certainty for wind project developers and optimises the development of the network. A further interesting feature is the development of a “wind cluster” concept which permits semi-dedicated MV networks...
The use of a series-connected self-excited synchronous generator for isolated distributed generation is investigated. Such a machine may be realized by connecting the stator and rotor windings of a slip-ring induction machine in series, but with reversed phase sequence. The advantage of the machine configuration is high power density and high-speed operation. Both phasor diagram and time-stepping...
The growth in renewable and distributed generation is driving the gradual evolution of the methods used to plan and operate transmission and distribution networks. Smart Grid technologies in the area of Active Network Management (ANM) are expected to facilitate the increased connection of renewable and distributed generators to electricity networks in the near-term. Other Smart Grid technologies are...
This paper discusses investment strategies in a microgrid system consisting of cogeneration system and renewable power generation under uncertainty in the natural gas price. Although incentives for introducing distributed energy system increase these days, volatile natural gas prices make its investment in gas fuel distributed generation systems risky. Therefore, it is important to evaluate the risk...
Voltage rise is a significant limitation when connecting large volumes of distributed generation (DG), particularly in rural distribution networks. One means of allowing further capacity penetration is to control voltage regulation devices such as on-load tap changers in a coordinated manner considering the variability of demand and generation. This approach, however, requires the deployment of communication...
This paper presents an approach to coordinate Distributed Generation (DG) such that quantities in an unbalanced distribution system are balanced and power factor corrected. Models for the DG and three-phase distribution network are combined to form a set of Differential Algebraic Equations (DAE) that represent the behavior of the distribution system. Two state-feedback controllers with reference inputs...
Active distribution networks have the capability to allow the distributed energy resources integration at reasonable costs, opening new business opportunities. Although the sharing of responsibility among the system stakeholders (e.g., the Civil Society, the DSO and DER owners) is essential, undeniably they pursue different, and sometimes opposite goals. The authors, by adopting multi objective programming...
This paper investigates the performance characteristics of rapeseed methyl ester, EN 14214 biodiesel, when used for electrical generation in compression ignition engines. The work was inspired by the need to replace fossil diesel fuel with a sustainable low carbon alternative while maintaining generator performance, power quality and compliance with ISO 8528-5. A 50 kVA Perkins diesel engine generator...
Distributed Generation (DG), has started becoming a reality in electricity networks. This analysis focuses more on a specific configuration of networks with DG, the Microgrid. Microgrids can operate in a coordinated way either interconnected to an upstream distribution network or autonomously in case of faults in the upstream medium voltage network, like the power systems of physical islands. Under...
The dynamic behaviour of a PWM voltage source inverter based voltage generator with an output LC filter is analyzed in this paper. This converter is able to participate to frequency regulation either in connected mode or in an islanded mode with minor modifications in the control algorithm. Thanks to a droop control, it is possible to achieve power sharing between this converter and a classical synchronous...
Microgrids are an emerging technology which promises to achieve many simultaneous goals for power system stakeholders, from generator to consumer. The microgrid framework offers a means to capitalize on diverse energy sources in a decentralized way, while reducing the burden on the utility grid by generating power close to the consumer. As a critical component to enabling power system diversity and...
Microgrid technologies are highly developed in low voltage networks, improving the power supply reliability and energy efficiency. Therefore, in this paper, the concept, including the configuration, principle and operation of microgrid, will be specified, comparing the microgrid with the prior distributed generation. Additionally, in order to justify the feasibility, the economical benefit analysis...
The growth of distributed generation or renewable generation resources and advanced information systems add uncertainties and complexity to the energy system and call for a “smart grid” solution. The mathematical models that are conventionally utilized in the energy management system usually take a long time to develop and execute and are not flexible enough to accommodate operational rules for generations...
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