• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.397-402
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• 2005

A new control algorithm of soft starter is proposed for the reduction of the inrush current during the grid connection of the induction-type wind power generator. Currently, the fixed speed wind turbine using induction generator is the most popular wind generation system in Korea. It is shown that the amount of inrush current mainly depends on the control algorithm of the soft starter, a thyristor-based grid connection device. For the simulation study, a 600kw wind turbine simulation model is developed and the transient waveforms are investigated with conventional md proposed methods. Also experimental results using 3.7kW experimental set-up show that the peak value of inrush current is reduced about 20$\%$ using proposed algorithm.

• Journal of Hydrogen and New Energy
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• v.32 no.6
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• pp.477-482
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• 2021

Hydrogen production, hydrogen production cost, and utilization rate were calculated assuming four cases of hydrogen production system in combination of photovoltaic power generation (PV), water electrolysis system (WE), battery energy storage system (BESS), and power grid. In the case of using the PV and WE in direct connection, the smaller the capacity of the WE, the higher the capacity factor rate and the lower the hydrogen production cost. When PV and WE are directly connected, hydrogen production occurs intermittently according to time zones and seasons. In addition to the connection of PV and WE, if BESS and power grid connection are added, the capacity factor of WE can be 100%, and stable hydrogen production is possible. If BESS is additionally installed, hydrogen production cost increases due to increase in Capital Expenditures, and Operating Expenditure also increases slightly due to charging and discharging loss. Even in a hydrogen production system that connects PV and WE, linking with power grid is advantageous in terms of stable hydrogen production and improvement of capacity factor.

• New & Renewable Energy
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• v.3 no.4
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• pp.69-76
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• 2007

In this paper, a PV multi-string PCS with a grid-connection is proposed. An improved MPPT algorithm for the PV multi-string PCS is suggested. Each PV string has its own MPP tracker and the proposed MPPT algorithm prevents LMPP tracking due to power ripple. In the PV PCS with single-phase inverter has a large current ripple at twice the grid frequency. The current ripple reduction algorithm without external component is suggested. Also, this paper proposes a simple control method to achieve sharing of the PV string voltage and current among the interleaved parallel boost converters. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3kW prototype show high performance of the proposed PV multi-string PCS.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.562-564
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• 2008

This paper deals with the three phase high voltage power-grid connection topology using multi-level inverter. Due to the multi-level inverter, these are improved effect of fluctuating voltage, problem of EMC and switching loss using suitable switching patterns of device, above all thing, it is easy to realize the system because of using lower voltage rating switch. This topology can be applicable to power-grid connection of wind system, there is a good point about economical efficiency. The simulation results are presented to verify the validity of the proposed topology.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.313-316
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• 2006

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. Korea Electric Power Corporation (KEPCO) has researched performance characteristics of the 60k W class 1) basic start-up & shutdown operation analysis 2) interconnection test 3) MGT -absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.255-258
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• 2007

In this paper, a PV multi-string PCS with a grid-connection is proposed. An improved MPPT algorithm for the PV multi-string PCS is suggested. Each PV string has its own MPP tracker and the proposed MPPT algorithm prevents LMPP tracking due to power ripple. In the PV PCS with single-phase inverter has a large current ripple at twice the grid frequency. The current ripple reduction algorithm without external component is suggested. Also, this paper proposes a simple control method to achieve sharing of the PV string voltage and current among the interleaved parallel boost converters. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3kW prototype show high performance of the proposed PV multi-string PCS.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.31-33
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• 1999

In this paper, a operating characteristics of the 50 kW grid-connected Photovoltaic(PV) Power system which is by means of initial PV datum analyzing is reported. The development of a 50 kW class photovoltaic power generation system including a DC/AC inverter is suggested to investigate the system performance for grid connection. The results of the demonstration test of a 50 kW class grid-connected PV system show that the system utilization rate is 15.6% and the inverter efficiency is 94% at 80% load.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1171-1173
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• 2000

This paper was analyzed the high-frequency harmonics, power conversion rate, results of the system's monitor, and measuring data of the system power output of a 3-phase photovoltaic power system for grid-connection. The photovoltaic power system consists of a 3-phase inverter array, and data acquisition system. The result of an analyzing data of the 50 kW class grid-connected photovoltaic system showed the stable behavior in utility-interactive operation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.772-773
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• 2007

This study suggests a modeling of grid-connected wind power generation system that has induction generator, and aims to perform simulations for outputs by the variation of actual wind speed and for fault current of wind generation system by the transformer winding connection. This study is implemented by matlab&simulink. The simulation shall be performed by assuming single line to ground fault generated in the system. Generator power, rotor speed, terminal voltage, system voltage, and fault current shall be observed following the performance of simulation. The fault current change will be dealt through the simulation results for fault current of wind generation system following the grid-connected transformer winding connection and the simulation result by the transformer neutral ground method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.454-457
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• 2007

This study suggests a modeling of grid-connected wind turbine generation system that has induction generator, and aims to perform simulations for outputs by the variation of actual wind speed and for fault current of wind generation system by the transformer winding connection. This study is implemented by MARTLB & SIMULINK. The simulation shall be performed by assuming single line to ground fault generated in the system Generator power, rotor speed, terminal voltage, system voltage, and fault current shall be observed following the performance of simulation. The fault current change will be dealt through the simulation results for fault current of wind generation system following the grid-connected transformer winding connection and the simulation result by the transformer neutral ground method.