• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.545-552
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• 2015

Process modeling and simulation is a powerful methodology to quantitatively predict the change of process variables when operating and design conditions are changed. In this study, considering drawbacks of currently used process simulator for combined cycle plants, we developed process modeling system equipped with an ease of use and flexibility for model development. For this purpose, the analysis of combined cycle processes was carried out and consequently, mathematical models and libraries were developed. Furthermore, in view of the fact that the level of the abstraction of process models depends on the purpose of simulation as well as the available data, simple and rigorous models were also developed for some important units. In use of reference combined plant, we executed process simulation using the developed modeling system and the comparison was made between the results of simulation and the reference data. Less than 1% marginal error was identified and we concluded that the modeling system can be applied for commercial combined cycle processes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.108-117
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• 2007

RConsumer Portal is defined as "a combination of hardware and software that enables two-way communication between energy service providers(ESP, like KEPCO) and equipment within the consumer's premises". The portal provides both a physical link(between wires, radio waves, and other media) and a logical link(translating among language-like codes and etiquette-like protocols) between in-building and wide-area access networks. Thus, the consumer portal is an important, open public shared infrastructure in the future vision of energy services. This paper presents an XML based standard specification of service-oriented, open protocol for consumer portal system architecture. In the framework level, the XML protocol provides a useful bridge between services and platforms. The proposed standard protocol has been implemented into our developing consumer portal pilot system. The results imply the potential of global standards for consumer portal system by its minimum overhead in network and processor. The reposed XML is designated psXML in this paper.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.491-498
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• 2020

Recently, In the production line of batteries, charge and discharge tests are essential to verify battery characteristics. In this case, the battery charging uses a unidirectional AC/DC converter capable of output voltage and current control, and the discharge uses a resistive load. Since this method consumes energy during discharge, it must be replaced with a bi-directional AC/DC converter system capable of charging and discharging. Although it is difficult to replace the connected inverter part of the bi-directional AC/DC converter system due to the high cost, the spread of the solar-connected inverter rapidly increases as the current solar supply business is activated, and thereby the solar-connected type Inverter prices are plunging. If it can be used as a power converter for battery discharge without program modification of the solar-powered inverter, it will have competition. In this paper, propose a new battery discharge system using a combination of a photovoltaic DC/DC simulator and photovoltaic PCS using a battery to be used as a power converter for battery discharge without program modification of a low-cost photovoltaic inverter. In addition, propose an optimal solar characteristic curve for the stable operation of PCS. The validity of the proposed system was verified using a 500[W] class solar DC/DC simulator and a solar PCS prototype.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.17-24
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• 2010

The power transfer capability has been recently highlighted as a key issue in many utilities with the power system more stressed and heavy loaded. The total transfer capability in the KEPCO power system is determined mainly by the voltage stability limit and many approaches for enhancement of the total transfer capability has been consistently performed. In this paper, a new transfer capability index to locate the STATCOM(Static Synchronous Compensator) effectively for enhancing the total transfer capability from a static voltage stability viewpoint is presented and it is applied to a small scale power system of IEEE 39-bus test system in order to show the effects of this index. In addition, the effect of transient stability as well as voltage stability to the total transfer capability when loads are increased is analyzed using this small scale power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.86-93
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• 2010

This paper presents the guideline for enhancing the reliability and availability of SAS with IEC 61850 based IEDs in real power system. The IEC 61850 standard communication networks and systems allow utilities to consider new designs for substations applicable both new substation and refurbishments. The existing solutions are based on hardwired interface between the primary substation equipment and the secondary protection, monitoring, control and recording devices. All over the world, lots of projects at different stages of realization have been reported during the last year leading to a rapid maturation of the associated technologies. At present, IEC 61850 is becoming a popular communication standard for the substation automation system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2149-2154
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• 2009

Electric power quality in power transmission/distribution systems has considerably been deteriorated with the increase in the capacity of distributed generators (DGs). It is because inverters, connecting DGs to conventional power grids, tend to generate harmonic current and voltage. For harmonic mitigation, a large amount of research has been done on passive and active filters, which have been operating successfully in many countries. This paper, therefore, presents how to adopt the filters to an inverter-based DG, with considering a system consisting of both inverter-based DG and harmonic filters. In particular, this paper describes the simulation results using the PSCAD/EMTDC: firstly, the relationship between total harmonic distortion(THD) of current and output power of DG: secondly, the harmonic mitigation ability of passive and active filters. The system, furthermore, is obliged to satisfy the regulations made by Korean Electric Power Corporation(KEPCO). In the regulations, power factor should be maintained between 0.9 and 1 in a grid-connected mode. Thus, this paper suggests two methods for the system to control its power factor. First, the inverter of DG should control power factor rather than an active filter because it brings dramatic decrease in the capacity of the active filter. Second, DG should absorb reactive power only in the range of low output power in order to prevent useless capacity increase of the inverter. This method is expected to result in the variable power factor of the system according to its output power.

• Korean System Dynamics Review
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• v.4 no.2
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• pp.153-171
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• 2003

In this study, we tried to build a model which can deal with the efficient and effective operation of electric power industry, especially focused on the nuclear industry. Here, SD(system Dynamics) approach is used to visualize the underlying phenomenon of the nuclear power industry. SD is a methodology for studying and managing complex feedback systems, such as one finds in business and other social systems, The span of SD applications has grown extensively and now encompasses work in corporate planning and policy design, public management and policy, biological and medical modeling, energy and the environment. Recently, according to the report from KEPCO(Korea Electric Power Corporation), they are considering delaying a new power plant construction. It may be based upon business fluctuation downsized from Korean economic crisis in 1997 and freezing of construction funds due to unstable foreign exchange rate. At this point, we need desperately a kind of strategic model that would contribute to cope with the current business situation, energy generation, Production, and resulting Pollution. Specifically, this model, using SD approach, starts with the detailed drawing of influence diagram, which describes those relevant key points on nuclear power generation systems in electric power industry of Korea. These include such (actors as the operation of nuclear industry and parameters related to the decision making for business policy. Based upon the above-mentioned influence diagram drawn, we developed SD simulation model to evaluate and analyze strategic management of KBPCO. Based on our analysis, we could demonstrate how simulation model can be applied to the real electric power generation in Korea.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.4
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• pp.210-220
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• 2002

We analysised the effect of harmonics on electric machines of substation power system barred on quantitatively measured harmonics and proposed the methods for prevention of harmonics through checking on transformer, rectifier and cable's capacities against harmonics with reference to KEPCO's electricity service standard. In order to analysis harmoninics of silicon rectifier that is power source in DC substation, computer simulations for a substation with TR of high voltage distribution switchboard are performed. Simulation results show that the total harmonic distortion factor becomes smaller for TR primary and receiving points in order rather than silicon rectifier which is harmonic generation source so that the harmonics generated frets each rectifier are outflowed to power supply and high voltage distribution switchboard The result of higher distortion factors of voltage and current for rectifier with 100% load than those with 50 % and 30% indicates that the waveform of voltage and current for the real substation power system at the office-going and the closing hours with heavy loads might be more distorted. As proposed methods for harmonic reduction, the conventional 6 pulse-type for substation is required to be replaced by 12 pulse-type for reduction of 5th and 7th harmonics. The active filter rather than the passive filter is more effective due to severe variance of rectifier loads, but the high cost is price to be paid. In view of installation area and costs, the use of 12 pulse-type transformer is desirable and then the parallel transformer and the rectifier within the substation must be replaced at the same time. Other substations with parallel feeder can use 6 pulse-type transformer.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.55-61
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• 2017

Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

• Journal of Hydrogen and New Energy
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• v.22 no.1
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• pp.118-127
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• 2011

An IGCC was evaluated as one of the next generation technologies that would be able to substitute for coal-fired power plants. According to "The 4th Basic Plan of Long-term Electricity Supply & Demand" which is developed by the Electricity Business Acts, the first IGCC will be operated at 2015. Like other new and renewable energy such as solar PV, Fuel cell, The IGCC is considered as non-competitive generation technology because it is not maturity technology. Before the commercial operation of an IGCC in our electricity market, its economic feasibility under the Korean electricity market, which is cost-based trading system, is studied to find out institutional support system. The results of feasibility summarized that under the current electricity trading system, if the IGCC is considered like a conventional plant such as nuclear or coal-fired power plants, it will not be expected that its investment will be recouped within life-time. The reason is that the availability of an IGCC will plummet since 2016 when several nuclear and coal-fired power plants will be constructed additionally. To ensure the reasonable return on investment (NPV>0 IRR>Discount rate), the availability of IGCC should be higher than 77%. To do so, the current electricity trading system is amended that the IGCC generator must be considered as renewable generators to set up Price Setting Schedule and it should be considered as pick load generators, not Genco's coal fired-generators, in the Settlement Payment.