• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.4
• /
• pp.210-220
• /
• 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 Korean Institute of Navigation
• /
• v.18 no.2
• /
• pp.91-109
• /
• 1994

Technological and organisational changes in transport system have introduced new dimension into port system development and inter-port competition. The quality of service now required by the customer is costly and not easily provided by small shipping companies and small ports. It has been suggested that in the future container shipping may be concentrated by space-sharing arrangements or actual mergers into the hands of a few mega-operators with the investment potential to provide total logistics networks. In order to compete effectively, high load factors will be essential and port concentration inevitable. A fa-voured few ports will become the load centres and other ports will assume a secondary feeder role. In this study, three questions are raised and attempts are made to answer them : (a) what is the new role of ports today ; (b) why should ports be engaged in this new role ; and (c) how can ports play this new role. In short, a modern port should be a service centre and a logistic platform for international trade and transport-a third generation port. Ports, in particular, have to make every effort to be competitive in the cost and quality of services and to make the port a transport and distribution service centre. For most ports, this is not an option but a must ; an essential requirement for survival in this win or lose situation. The best way to win is to maintain a close contact with port users, listen to them, discuss with them, help them and satisfy them. That is port marketing. Starting from the findings of port marketing, it is es-sential to work out appropriate development plans and marketing targets and to improve port competitive-ness. As an alternative method, a port competitiveness model is suggested, which may help port managers to make appropriate improvements.

• Journal of Navigation and Port Research
• /
• v.33 no.7
• /
• pp.491-500
• /
• 2009

In order to attract more transshipment cargoes, Busan Port Authority (BPA) has, since 2003, adopted the volume incentive policy by which more than US$ 10 million annually have been paid back to shipping lines that were called at the port. However, having been a transshipment port for the Northeast region of China, the port of Busan has come under threat from bold Chinese port development projects, notably Shanghai, as northern Chinese regionnl ports place more emphasis on building facilities capable of handling growing trade volumes. Undoubtedly this would lead to a decline in transshipment container traffic moved via Busan. The purpose of this paper is to identify some core factors that have been affecting the increase of transshipment cargoes of Busan and further to recommend BPA an improved incentive scheme with which more T/S cargoes can be attracted into the port of Busan To clarity the reason why T/S cargoes have increased in the port of Busan, several steps are made as follows: The first step is to make a quantitative model for explaining the development of T/S cargoes during the last decade. The second step is to define the dependent and the independent variables for multiple regressions after testing variable significance. For this, data collection and the accuracy of validation have been done by the direct interview with the experienced staffs in shipping companies of both domestic and foreign country. After validating the model with collected data, the final step is to find variables which are explaining the model mostly. In conclusion, 2 variables were clearly identified as core factors that explain well the development of T/S cargoes in the port of Busan: 'Mohring effect' and total cost. It is strongly recommended, by an empirical study, that an incentive scheme be changed to a way which more feeder vessels rather than mother vessels can reduce their direct costs to call in the port of Busan.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.13 no.4
• /
• pp.247-256
• /
• 2008

Regenerative energy generated by regenerative braking of DC traction can cause the system malfunction or damage to the rectifier, or malfunction of the power conversion device in power supply system by DC Line voltage rise in feeder line. Regenerative energy storage system using super capacitor is one of the ways to stabilize DC line voltage. In this paper, energy storage system of DC traction system using super-capacitor bank is implemented and using the field measurement data of the station N and the station S on the Line 2, the operation characteristics of line voltage caused by regenerative energy of electric trains are verified. Also, charge/discharge characteristics of super capacitor are verified as well. Thus, we can verify the operation characteristics of super-capacitor bank for regenerative energy storage system installed in DC Traction. And if we can use field measurement data of DC line voltage, we have obtained cost reduction. The stabilization of the system will be improved by measuring the operation characteristics of regenerative energy storage system in certain section operated by DC traction and predicting the capacity and lifetime of super-capacitor.

• Journal of Korea Port Economic Association
• /
• v.24 no.1
• /
• pp.41-60
• /
• 2008

Korea has been doing a two-port system as a main port development policy and developing the port of Busan and Gwangyang as the transshipment hubs in the northeast Asia. However, the growth rate of the transshipment container volume of the Gwangyang port in 2007 was sharply dropping more than 31.4%. The reasons why reduced the growth rate of transshipment cargo were from the port development in north China and the direct callings of ships. Therefore, it is time to evaluate the transshipment hub port policy of Korea. This study would recognize the decision criteria of shipping companies as customers for the transshipment hub in the northeast Asia by the AHP methodology based on Lirn et al. (2004). It has been known the costs of shipping companies and port location as the main first tier criteria for transshipment ports, and container handling charges, closeness to the main navigation route, carriers' strategy, and nearness to the feeder ports as the important second tier factors. Finally, the domestic terminal operating companies would focus on only a few attributes including the terminal cost factor, but the international shipping companies would be considering more several factors than they do. Therefore, the transshipment port strategy should be enriched in the near future.

• Journal of Korea Port Economic Association
• /
• v.23 no.1
• /
• pp.115-148
• /
• 2007

Under the influence of ever-globalized world economy, Yangsan Port of Shanghai, a central hub of Chinese economy, was opened up on Dec. 1, 2005 in the expectation of heart of northeast Asian harbor logistics. It has triggered severer competitions among northeast Asian ports. In an effort to keep robust standing as a central port of northeast Asia, Korea has still built additional new ports and opened up 3 docks in Nov. 2005. Amid these changing port environments, it is foremost to take the competitive edges of new ports in advance of major rival ports in the interest of preoccupying the standing of those new ports as the central hub of northeast logistics. According to the developmental strategies of new ports can be summed up as follows: First, it is required to separate port development from marketing as a part of separating developmental entity from management/maintenance entity. Second, it is required to develop dedicated port for feeder vessels along with new ports to save more time and cost spent by shipping companies. Third, the attraction of jumbo shipping companies to port development needs differentiated countermeasures for each shipping company, and those measures should be taken in advance before jumbo shippers decide their own shipping strategies in future. Fourth, in terms of incentives for attracting jumbo shipping companies, it is required to offer the incentives to them in using new ports in connection with Busan ports. Fifth, it is critical to set up a benchmark of competitors(ports) for establishing one-stop automatic administration process system upon developing ports. Finally, it is required to prepare a plan for using rearward lands in connection with ports for more efficient use of development complex behind port.

• Resources Recycling
• /
• v.6 no.3
• /
• pp.15-21
• /
• 1997

Flyash from a coal-hed power plan1 is produced approximtcly 3 million tons m 1996 and causes the serious environmentalpmblem due to the disposal in the ash pond. Flyash is an accepted additive in concrete where it adds strength, sulfate ateresistanceand reduced cost, provided acccptablc levcls of unbunrned carbon are mmtmed This papzr describes to investigate thc technicalfeasibility of a dry triboelcctrostatlcp roccss to scparate unburned carbon h m f lyash into economically valuable produck Puliclesof unburned carbon and flyash can be impded positivc and negative surface charzes. rcapeclively. with a copper tniochargcr dueto dirferences in the work function values of thc particles and the tnbacharger. and cm he separated by passing thcm throuph anexternal electic field. A laboratory s d e separation system consists of r sacw feeder for ash supply, a tniocharger, verticalcollecling copper plates, power supplies, a flow meter, and a fan. Separation tests taking into account separahian efficiency and ashrecovery showed that flyash recovery was sh-nngly dependent an thc tnbocharger geomzhy, elect"c ficld strength. flyssh s ~ c a,n dash feeding late. Optimal separation conditions were flyash size less than 125 Fm and electric field shcngrh of 200 kV1m. Ovcr 80%of the flyash with 7% lass on ignition was recovered at wrbon contznts less than 3%bon contznts less than 3%

• Journal of Korea Port Economic Association
• /
• v.30 no.1
• /
• pp.175-194
• /
• 2014

Because the thawing of the Arctic ocean is slowly accelerating due to global warming, recently exploring resources in Arctic ocean and transporting resources by using the North Pole route have been getting spotlight. Since the original route transported by the Suez Canal from Korea to Europe could be shorten about 8,000km in distance(decreased about 38% compared to the original route), which means shortening about 10 voyage dates, it is expected to bring huge logistics cost reduction. Once the North Pole route is commercialized successfully, it would be one of the most important variables that affects future of Busan port and guides for economic development of Busan. Therefore, the purpose of this study is to analyze Busan port and the economic growth of Busan area by researching promising industry, based on the effect of freight transporting by the Northern sea route on the economy of Busan. For this study, questionnaire surveys and interviews were conducted for 64 people of experts in the shipping and port industry, relevant government, and academics. The survey finding shows that port logistics industry is a promising business in Busan in terms of its growth and competitiveness. It is necessary to develop feeder network facilities that prepare for commercialization of the Northern sea route as a short and medium term plan and provide professional manpower training in polar regions. Ship supply business would also play an important role. It is identified that revitalization of shipbuilding and ocean plant industry should be done in terms of Arctic business. With regard to the fishery industry it is found that modernization of fishery ship and development of fishery equipment used in polar areas should be carried out.