• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.102-108
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• 2015

This paper proposes a new fault isolation methodology for a smart protective device which plays an agent role on the smart grid distribution system with the distributed generation. It, by itself, determines accurately whether its protection zone is fault or not, identifies the fault zone and separates the fault zone through the exchange of fault information such as the current information and the voltage information with other protective devices using bi-directional communication capabilities on the smart grid distribution system. The heuristic rules are obtained from the structure and electrical characteristics determined according to the location of the fault and DG (Distributed Generation) when faults such as single-phase ground fault, phase-to-phase short fault and three-phase short fault occur on the smart grid distribution system with DG.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.83-86
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• 2006

A grid-connected distributed generation system which consists of engine generator, dc link with multiple energy sources and inverter is proposed. All six of the stator leads of the generator, which is a surface mount permanent magnet machine, are brought out to the terminal of the generator. Three leads are connected to the inverter and the others are connected to the utility grid. In this proposed system the power from the engine-generator and the power from dc link can be controlled simultaneously by only one three-phase power converter. A control algorithm for the system is developed and verified by experiment results.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.295-309
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• 2019

This paper demonstrates that the verification and analysis of the increase of hosting capacity of distributed energy resources in distribution system for the high penetration of distributed energy resources. In the case of generally designed distribution feeders in South Korea, it can host up to 10 MVA of distributed energy resources and the over voltage due to reverse power flow is prohibited beyond the range by the law of electric utility. However, it should take into consideration that there are some factors of extra hosting capacity such as generation characteristics of distributed energy resources and minimum loads that always exist to distribution system. For these reason, we choose a specific distribution system hosted 10 MVA of distributed energy resources monitored by distribution system operator and verify the impact of increasing hosting capacity such as power flow and voltage profile of distribution system. By the result, we could find that it is possible to increase the hosting capacity and define the factors to expand the hosting capacity of distributed energy resources in distribution system.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.409-413
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• 2006

This paper deals with the design and testing of a simulator system for microgrids with distributed generations. This system is composed of a Real Time Digital Simulator (RTDS) and a power amplifier. The RTDS parts are operated for real time simulation for the microgrid model and the distributed generation source model. The power amplifiers are operated fur amplification of the RTDS's simulated output signal, which is a node voltage of the microgrid and distributed generation source. In this paper, we represent an RTDS system design, specification and test results of a power amplifier and simulation results of a PV (Photovoltaic) system and wind turbine system. The proposed system is applicable for development and performance testing of a PCS (Power Conversion System) for renewable energy sources.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.107-109
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• 2003

This paper studies islanding detection distributed of distributed generation(DG). The study of islanding detection has been disconnected DG when power islanding was detected but fault type wasn't distingish. Nearby feeder fault the fault of feeder that not interconnected DG, is a little affect DG and distribution system. Therefore DG not need to disconnect distribution system. We studied islanding detection algorithm considering fault location.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.94-100
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• 2016

A virtual power plant (VPP) technology is a cluster of distributed generation installations. VPP system is that integrates several types of distributed generation sources, so as to give a reliable overall power supply. Virtual power plant systems play a key role in the smart grids concept and the move towards alternative sources of energy. They ensure improved integration of the renewable energy generation into the grids and the electricity market. VPPs not only deal with the supply side, but also help manage demand and ensure reliability of grid functions through demand response (DR) and other load shifting approaches in real time. In this paper, utilizing a variety of distributed generation resources(such as emergency generator, commercial generator, energy storage device), activation scheme of the virtual power plant technology. In addition, through the analysis of the domestic electricity market, it describes a scheme that can be a virtual power plant to participate in electricity market. It attempts to derive the policy support recommendation in order to obtain the basics to the prepared in position of power generation companies for the commercialization of virtual power plant.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1386-1396
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• 2017

In this paper, a new approach is proposed to select the optimal sitting and sizing of distributed solar photovoltaic generation (SPVG) in a radial electrical distribution systems (EDS) considering load/generation uncertainties. Here, distributed generations (DGs) allocation problem is modeled as optimization problem with network loss based objective function under various equality and inequality constrains in an uncertain environment. A boundary power flow is utilized to address the uncertainties in load/generation forecasts. This approach facilitates the consideration of random uncertainties in forecast having no statistical history. Uncertain solar irradiance is modeled by beta distribution function (BDF). The resulted optimization problem is solved by a new Dynamic Harmony Search Algorithm (DHSA). Dynamic band width (DBW) based DHSA is proposed to enhance the search space and dynamically adjust the exploitation near the optimal solution. Proposed approach is demonstrated for two standard IEEE radial distribution systems under different scenarios.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.651-659
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• 2008

Autoreclosing techniques have been used in power systems to maintain system stability and continuity of supply. Environmental and economical issues have driven significant increases in the development of distributed generation (DG). DG connected to distribution systems, however, may impose negative influences with respect to power quality, protection, and stability, because DG can cause some challenges to protection, especially to reclosing. For this reason, in order to improve the reliability and safety of the distribution system, the rules and guidelines suggest that the DG system needs to be rapidly disconnected from the system before reclosing. We present, in this paper, an adaptive reclosing algorithm considering the DG. The algorithm consists of an angle oscillation's judgment, the emergency extended equal-area criterion (EEEAC), the calculation of an optimal reclosing time, and a reconnection algorithm. Our simulation results for three different DG technologies with Electromagnetic Transient Program (EMTP) indicate that we can maintain transient stability while the DG is protected against disturbances.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.313-315
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• 2005

Recently There has been growing interest in new renewable energy systems with high-energy efficiency due to the increasing energy consumption and environmental pollution problems. But an insertion of new distributed generation to existng power distribution systems can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc, because of reverse power. This paper was applied to fault location defecting a method as each Relay sensing fault current value and carried out short-circuit analysis by MATLAB and PSCAD/EMTDC programs and identity the faulted section o f22.9[kV] distribution system interconnected a large number of distributed generation. The existing protection system of 22.9[kV] power distribution system analyzed and the study on protective coordination recloser and Sectionalzer accomplished

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.227-232
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• 2007

The autoreclosing is applied to power system for maintaining system stability and continuity of supply. Developments on distributed generation(DG) grows significantly by environmental issues and economical issues. If the DG is connected to distribution system, the DG influences the technical aspects such as power quality, protection and stability. It causes the challenges to protection, especially to reclosing. In order to achieve reliability and safety of the distribution system, the rules and guidelines suggest that the DG units should be rapidly disconnected from the network before the reclosing. If the DG is disconnected whenever the fault occurs, it cannot be utilized effectively. This paper presents the adaptive reclosing algorithm considering the DG. The algorithm consists of angle oscillation's judgment, EEEAC(Emergency Expanded Equal-Area Criterion), calculation of optimal reclosing time and re-connection algorithm. The simulation is implemented for the DG technology by using EMTP MODELS. The simulation results show that the transient stability is maintained and the DG is protected against disturbance.