• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.2
• /
• pp.74-79
• /
• 2002

We have been analyzed the interference problems already in steady state, especially AC corrosion when the gas pipeline is burred with power cable in the same submarine tunnel. In the next stage, we analyze the induced voltage in a fault condition of 154[kV] underground T/L. This paper presents the results of them which are limitation of safety voltage. meodeling of power cables, gas pipeline and grounding systems, analysis of induced voltage in a fault condition, and protection of Power line system.

• Journal of the Korean Institute of Gas
• /
• v.12 no.1
• /
• pp.19-24
• /
• 2008

Due to industrialization and urbanization, underground metallic utilities with different owners have been rapidly increased and cathodic protection (CP) methods, especially impressed current CP systems, have been widely adopted to protect their utilities from corrosion with expanded recognition of this method. The stray current interference problem as well as the difficulty in spatial security for system installation, however, came to a ramification of which each owner couldn't resolve for himself. In this respect, this paper illustrates a field-diagnosed example for mutual interference due to separately operated CP systems and suggests an alternative method to overcome the interference situation by design and field-assessment of a common anode bed cathodic protection system.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.3172-3174
• /
• 2000

It is necessary to collect and analyze the corrosion date to control the underground metallic structures systematically. It can be possible to predict the remaining life of underground metallic structures. In this paper we describe the life prediction technology of cathodic protection systems and underground metallic structures without a cathodic protection system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.10a
• /
• pp.105-114
• /
• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction of 9 new ports and renovation of the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built of steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions of structures and increased underwater construction period. for the purpose of cutting down the government budget, it is necessary to extend the life cycle of the existing structures. We developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction of maintenance expenses and time for anti-corrosion work but also better protection. This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.205-208
• /
• 2007

We aim to develop antifreezing coolant used to in the 200kW Fuel Cell system that is possible to starting at low temperature and that must not to be freezed under $-30^{\circ}C$, have high coductivity, excellent system protection ability and durability.

• Corrosion Science and Technology
• /
• v.9 no.6
• /
• pp.331-337
• /
• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Proceedings of the KIEE Conference
• /
• 1997.07c
• /
• pp.803-806
• /
• 1997

The AC induced voltage on underground pipelines not only do harm to workers and instruments, but also cause big trouble in some case. This paper gives the mechanisms, examples, and countermeasure for the AC induced voltages which are caused by the resistive coupling between the grounding system of the 22.9kV distribution power system and the underground pipeline.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.4
• /
• pp.76-82
• /
• 2018

Grout in duct is very effective protection from tendon corrosion in PSC(Prestressed Concrete) structure. In the work, durability and mechanical tests are performed for two types of grout which are conventionally used one and the improved grout with reduced w/c (water to cement) ratio and silica fume. Tendon system with 1000mm height is prepared and various tests including strength, flow, absorption, and bleeding ratio are conducted. ICM(Impressed Current Method) is adopted for corrosion acceleration in tendon with 12.7mm diameter inside grout. For 2 and 4 days, corrosion acceleration is performed for 2 different type of grout and corrosion amount is investigated. The improved grout shows higher compressive strength by 10 MPa and lower absorption ratio by 50% than the conventional one. It also provides an excellent corrosion reduction to 39.8 %~48.2 % for 2~4 days of acceleration period.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2732-2734
• /
• 2005

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential due to stray current of subway system. So, we have developed the Real-time Wireless Remote Monitoring System for Stray Current of Subway System. In this system, the permanent buried type reference electrode is necessary. In this paper, results of development about the permanent buried type reference electrode($Cu/CuSO_4$) are presented.

• Journal of Surface Science and Engineering
• /
• v.40 no.6
• /
• pp.262-270
• /
• 2007

Recently, there has been a new appreciation of aluminum alloys as materials that are capable of reducing the environment load. This is because aluminum alloys are lightweight, easy to recycle, permit miniaturization, and have environmental friendly properties. In this study, we investigated the mechanical and electrochemical properties of 5083F aluminum alloys using slow strain rate test(SSRT) and potentiostatic tests under various potential conditions. In the potentiostatic tests, the current density in the potential range from -0.7 to -1.4V after 1,200 s was low. After considering the results of the potentiostatic tests, maximum tensile strength, yield strength, elongation, time-to-fracture, observation of fractured specimen and fractography analysis, the optimum protection potential range was between -1.3 and -0.7V(Ag/AgCl).