E. S. Elmubarak, A. M. Ali. Published High levels of penetration of distributed generation (DG) are a new challenge for traditional electric power systems. Power injections from DGs change network power flows, modifying energy losses and voltage profile of the system. This paper starts from the observation that there is a renewed interest in small-scale electricity generation literature review and outline of the Swiss situation Author(s): Koeppel, Gaudenz Publication Date: Distributed Generation-Literature Review and Outline of the Swiss Situation Gaudenz Koeppel Internal Report Z¨urich, November a definition for distributed generation is provided, serving as a discussion basis for the subsequent The amount of distributed generation (DG) is increasing worldwide, and it is foreseen that in the future it will play an important role in electrical energy systems. DG is located in distribution networks close to consumers or even in the
Protection of Distributed Generation: Challenges and Solutions
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Need an account? Click here to sign up. Download Free PDF. Tomas Gomez. Download PDF Download Full PDF Package This paper. A short summary of this paper. Impact of distributed generation on distribution investment deferral. Supervisor: Pukar Mahat Integration of a DG into an existing Project group: distribution system has many impacts on the system, with the power system protection being one of the major issues.
Short circuit power of a distribution system changes when its state changes. This Angel Fernández Sarabia may result in elongation of fault clearing time and hence disconnection of equipments in the distribution system or unnecessary operation of protective devices.
In this thesis, the effect of DG penetration on the short Copies: 2 circuit level has been analyzed in a Pages, total: distribution system with wind turbine and Appendix: 1 gas turbine generators. Different cases have been studied.
Location and technology of the DG sources are changed to study the effect that these changes may have on the coordination of protective directional over- current relays. By signing this document, each member of the group confirms that all participated in the project work and thereby that all members are collectively liable for the content of the report.
His support, understanding and expertise have been very important in completing this research. I want to take this opportunity to thank my parents and family for their love, constant support and their precious advice through my life. Interconnecting DG to an existing distribution system provides various benefits to several entities as for example the owner, utility and the final user. DG provides an enhanced power quality, higher reliability of the distribution system and can peak shaves and fill valleys.
However, the integration of DG into existing networks has associated several technical, economical and regulatory questions. Penetration of a DG into an existing distribution system has many impacts on the system, with the power system protection being one of the major issues.
DG causes the system to lose its radial power flow, besides the increased fault level of the system caused by the interconnection of the DG. Short circuit power also changes when some of the generators in the distribution system are disconnected.
This may distributed generation literature review and outline of the swiss situation in elongation of fault clearing time and hence disconnection of equipments in the distribution system or unnecessary operation of protective devices. Therefore, new protection schemes for both DG and utility distribution networks have been developed in the recent years but the issue has not been properly addressed.
In this thesis, the effect of DG penetration on the short circuit level has been analyzed in a distribution system with wind turbine and gas turbine generators.
Location and technology of the DG sources are changed to study the effect that these changes may distributed generation literature review and outline of the swiss situation on the coordination of protective directional over-current relays DOCR. Results are compared to that of the normal case to investigate the impact of the DG on the short circuit currents flowing through different branches of the network to deduce the effect on protective devices and some conclusions are documented.
The power flows only in one direction: from upper voltage levels down-to customers situated along the radial feeders. generation, transmission and distribution. Second stage is accomplished with the support of various equipments such transformers, overhead transmission lines and underground cables.
The last stage is the distribution, the link between the utility system and the end customers. This stage is the most important part of the power system, as the final power quality depends on its reliability [2].
The electricity demand is increasing continuously. Consequently, electricity generation must increase in order to meet the demand requirements.
Traditional power systems face this growth, installing new support systems in level 1 see figure 1. Whilst, addition in the transmission and distribution levels are less frequent. New technologies allow the electricity to be generated in small sized plants. Moreover, the increasing use of renewable sources in order to reduce the environmental impact of power generation leads to the development and application of new electrical energy supply schemes.
In this new conception, the generation is not exclusive to level 1. Hence some of the energy-demand is supplied by the centralized generation and another part is produced by distributed generation.
The electricity is going to be produced closer to the customers. These generators are of considerable smaller size than the traditional generators thermal, nuclear, etc… [3]. An overview of some common benefits and drawbacks of the DG are presented below: 1 Benefits [4] Connection of DG is intended to increase the reliability of power supply provided to the customers, using local sources, and if possible, reduce the losses of the transmission and distribution systems.
Therefore, the system can withstand higher loading situations. Many countries are subsidizing the development of renewable energy projects through a portfolio obligation and green power certificates.
This incentives investment in small generation plants. Besides, renewable energy based DG like photovoltaic and wind turbines contribute to the reduction of greenhouse gases.
Therefore, relay settings should be changed and if there is a disconnection of DG, relay should be changed back to its previous state. Renewable sources can be used in either small-scale applications away from the large sized generation plants or in large-scale applications in locations where the resource is abundant and large conversion systems are used [5]. Nevertheless, problems arise when the new generation is integrated with the power distribution network, as the traditional distribution systems have been designed to operate radially, distributed generation literature review and outline of the swiss situation, without considering the integration of the this new generation in the future.
In radial systems, the power flows from upper terminal voltage levels down to customers situated along the radial feeders [4]. Therefore, over-current protection in radial systems is quite straightforward as the fault current can only flow in one direction. In this new configuration, design considerations regarding the number, size location and technology of the DG connected must be taken into account as the short circuit levels are affected and miss coordination problems with protection devices may arise [7], [8].
This research addresses some of the issues encountered when designing the over- current protection coordination between protection devices, in case that a number of DG sources are connected to a radial system. The electricity is considered as the main distributed generation literature review and outline of the swiss situation of the plant. It is organized as follows: Chapter 1: Introduction This chapter gives a brief introduction to the concept of distributed generation reflecting the importance of DG systems to both the utility network and customers, besides the drawbacks occurring if DG is connected to the distribution systems.
Chapter 2: Literature Review This chapter is divided into six sections: the first section is a brief introduction and a definition of DG, followed by the second section which discusses the various types of distributed generation technologies and their nature. The impacts of DG on power system grids are discussed in the third section. Section four high lights one of the most important issues to maintain a safe operation of the DG, the protection coordination.
Section five is an overview of one of the major problems, islanding, that miss-protection can lead to and causes difficulties in system restoration. Finally the last section discusses the impact of DG penetration on the distribution feeder protection and the miss-protection problems arising from the interconnection of DGs. The second section describes the types of over-current relays and some of their main features.
Section three explains the model of the over-current relay created in DIgSILENT used throughout this thesis. Finally, in section four a practical application example using a small test distribution system and the proposed relay model is given.
Some simulations are carried out using the test system and the main problems encountered in protection coordination of relays, both with and without distributed generation installed in the system are shown. Chapter 4: Modelling and Simulation results In this chapter, simulations results with different DG configurations are presented.
The chapter is divided into five sections: the first section describes the modelling of the distribution system. In the second section, design of the over-current relay protection is explained, illustrating two main cases: firstly in Case 1, the test system is analyzed without the presence of DG, it is the base case that results are compared to. Then, in Case 2, the test network topology is modified introducing DG at different locations, distributed generation literature review and outline of the swiss situation, as well as, changing the DG technology, showing the effect on the level of short circuit currents.
In the section three, it is described the modelling of the modified distribution system. Section four, describes the design of the over-current relays protection for this modified system, several case are analyzed for different levels of penetration of DG. A small discussion on the results is made at the end of each case and some conclusions are drawn.
The last section presents, some solutions that may be implemented to overcome the issues found with over-current protection of distributed system. Chapter 5: Conclusion Some conclusions are presented in this chapter. The chapter ends naming some of the works that can be done in the future with reference to the work presented in this research. Appendix It presents data for test systems, generators, excitation system and speed governor.
There is not a common accepted definition of DG as the concept involves many technologies and applications. Furthermore, there are variations in the definition proposed by different organizations IEEE, CIGRE… that may cause confusion. To clarify about the DG concept, some categories that define the size of the generation unit are presented in Table 2. Table 2. Normally, inverters are used in DG systems after the generation process, as the generated voltage may be in DC or AC form, but it is required to be changed to the nominal voltage and frequency.
Therefore, it has to be converted first to DC and then back to AC with the nominal parameters through the rectifier [10]. In this chapter, some of the DG technologies, which are available at the present: photovoltaic systems, wind turbines, fuel cells, micro turbines, distributed generation literature review and outline of the swiss situation, synchronous and induction generators are introduced.
In this system, semiconductive materials are used in the construction of solar cells, which transform the self contained energy of photons into electricity, when they are exposed to sun light. The cells are placed in an array that is either fixed or moving to keep tracking the sun in order to generate the distributed generation literature review and outline of the swiss situation power [9].
These systems are environmental friendly without any kind of emission, easy to use, with simple designs and it does not require any other fuel than solar light. On the other hand, they need large spaces and the initial cost is high.
In Fig. There are two general designs that are typically used: with and without battery storages. The wind is a highly variable source, which cannot be stored, thus, it must be handled according to this characteristic.
A general scheme of a wind turbine is shown in Fig. First the rotor extract the kinetic energy of the wind, changing it into mechanical torque in the shaft; and in the second step the generation system converts this torque into electricity. In the most common system, the generator system gives an AC output voltage that is dependent on the wind speed.
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Our online essay writing service delivers Master’s level Distributed Generation Literature Review And Outline Of The Swiss Situation writing by experts who have earned graduate degrees in your subject matter. All citations and writing are % original/10() E. S. Elmubarak, A. M. Ali. Published High levels of penetration of distributed generation (DG) are a new challenge for traditional electric power systems. Power injections from DGs change network power flows, modifying energy losses and voltage profile of the system. This paper starts from the observation that there is a renewed interest in small-scale electricity generation Distributed generation (DG) is the future of energy. This technology allows the bidirectional flow of power within an electrical network. Researchers are faced with many challenges to the accurate implementation of protection schemes for DG-connected distribution network. The schemes designed must satisfy the performance requirements of selectivity, reliability, and
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