• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.122-128
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• 2004

With the advent of distributed generation, power systems are fundamentally impacted in regards to stability and power quality. Distributed generation has a positive impact on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has a negative impact on decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it becomes complicated to analyze a power system with distributed generation. The types of distributed generation are usually classified by both rotating machinery and the inverter-based system. In this paper, distributed generation is designed by rotating machinery, and the distributed system having a model of the distributed generation is simulated using EMTP. In addition, this paper presents the simulation results according to the types of distributed generation.

• KIEE International Transactions on Power Engineering
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• v.4A no.4
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• pp.201-206
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• 2004

With the advent of distributed generation, power systems in general are impacted in regards to stability and power quality. Distributed generation has positive impacts on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has negative impacts on the decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it is complicated to analyze power systems that have distributed generation. The types of distributed generation usually are classified as the rotating machinery system and the inverter-based system. In this paper, distributed generation is designed as a synchronous generator, and the distribution system with its distributed generation model is simulated using EMTP. In addition, this paper shows the simulation results according to the types of distributed generation

• Journal of Power Electronics
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• v.9 no.3
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• pp.447-455
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• 2009

The power supply systems, which require low-voltage / high-current output has been changing from the conventional centralized power system to a distributed power system. The distributed power system consists of a bus converter and POL. The most important factor is the system stability in bus architecture design. The overlap between the output impedance of a bus converter input impedance of POL causes system instability and has been an actual problem. By increasing the bus capacitor, the system stability can be easily improved. However, due to limited space on the system board, the increasing of bus capacitors is impractical. An urgent solution of this issue is strongly desired. This paper presents the output impedance design for on-board distributed power system by means of three control schemes of a bus converter. The output impedance peak of the bus converter and the input impedance of the POL are analyzed and then conformed experimentally for stability criterion. Furthermore, the design process of each control schemes for system stability is proposed.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.143-151
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• 2008

This paper presents the operation of Fuel Cell Distributed Generation(FCDG) systems in distribution systems. Hence, modeling, controller design, and simulation study of a Solid Oxide Fuel Cell(SOFC) distributed generation(DG) system are investigated. The physical model of the fuel cell stack and dynamic models of power conditioning units are described. Then, suitable control architecture based on fuzzy logic and the neural network for the overall system is presented in order to activate power control and power quality improvement. A MATLAB/Simulink simulation model is developed for the SOFC DG system by combining the individual component models and the controllers designed for the power conditioning units. Simulation results are given to show the overall system performance including active power control and voltage regulation capability of the distribution system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.3
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• pp.152-160
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• 2004

A novel UPQC(Unified Power Quality Conditioner), which consists of series inverter, shunt inverter, distributed generation system, is proposed. The proposing system can compensate reactive power, harmonics, voltage sag and swell, voltage interruption etc. through the change of paralleling operation mode and islanding operation mode. The control strategy for the proposing system was derived using the instantaneous power method. The performance of proposing system was analyzed by means of the PSCAD/EMTDC simulation and the experimental work with the hardware prototype. The proposing system has the ultimate capability of improving power quality at the point of installation on power distribution systems or Industrial power systems and can be utilized for the custom power device in th future distribution system.

• Plant Journal
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• v.17 no.3
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• pp.34-36
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• 2021

The interest in renewable energy-based distributed power generation systems is increasing due to the recognitions of the breakthrough of existing centralized power generation, energy conversion, and environmental problems. In this study, the optimal capacity was selected by simulating a distributed power generation system based on PV and WT using lead acid batteries as the energy storage system. CHP was adopted as the existing power source, and the optimal capacity of the system was derived through MOGA according to the operating modes(full load/part load) of the existing power source. In addition, it was confirmed that the battery life differs when the battery charging method is changed at the same battery capacity. Therefore, for economical and stable power supply and demand, the capacity selection of the distributed generation system considering the battery charging method should be performed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.335-339
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• 2016

Output power in photovoltaic systems changes steeply with the change of the sun intensity. The change of output power has influence on the electric power quality of the system. This paper proposes a residential distributed generation system using photovoltaic power generation and polymer electrolyte fuel cells(hybrid systems). In order to level the output power which changes steeply the polymer electrolyte fuel cells are connected to the photovoltaic power generation system in parallel. Thus the generated power of all the system can be leveled. However, the steep generated power in the photovoltaic power generation system can not be leveled. Therefore, the electric double layer capacitor(EDLC) is connected in parallel with the hybrid systems. It is confirmed by the simulation that the proposed distributed generation system is available for a residential supply.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2119-2124
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• 2010

Reliability evaluation of power distribution system is the evaluation for all customers supplied from one power source as main transformer located in substation. However, power sources include not only the main transformer but distributed generations. Typical reliability evaluation has focused on configuration of power system with one source including failure rates of equipment. In this paper, we focus on not only configuration but power sources as distributed generations. New reliability evaluation method using power supplied probability (PSP) is proposed. The proposed evaluation method are proved through case studies.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.36-44
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• 2013

This paper is written for the development and application of boiler fuel control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. Fuel control algorithm has the upper algorithm and it is boiler master control algorithm that controls the fuel, feed water, air by generation output demand. Generation output demand by power load influences fuel control. Because fuel can not be supplied fast to the furnace of boiler, fuel control algorithm was designed adequately to control the steam temperature and to prevent the explosion of boiler. This control algorithms were coded to the control programs of distributed control systems which were developed domestically for the first time. Simulator for coal-fired power plant was used in the test step. After all of distributed control systems were connected to the simulator, the tests of the actual power plant were performed successfully. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.714-716
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• 2004

Owing to the environmental problems as well as increasing energy prices and power plant construction costs, many researches have been made for the safe operation of distributed generations. In order to be more popularly used in parallel with the distribution network, the distributed generation and its correlation with the power system should be exactly monitored at any time. This paper presents a monitoring system which displays the important states of the distributed generation in operation and stores various measurements of the system. The proposed system constructs a data-base for developing algorithms against any faults of the interconnected system, and monitors efficiently at any place with the communication network function.