• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.161-164
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• 1992

In operation of power systems, operators must solve overloads in abnormal conditions instantaneously for restoring the power system to normal state. Earlier works proposed the power flow distribution and the load shedding decision, developed by the expert system, for settling overloads. This paper presents a method for solving special conditions in the earlier works which requires less amount of loads than that of the load shedding, in particular, of the load shedding considering the priority. This paper uses the effort system to improve the ability of a beginner as well as of trained operators for operating the power system during emergency operation. To prove efficiency of the proposed method, this paper has adopted the model system with 13 bus for obtaining simulation results and used the prolog language to implement the system.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.593-598
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• 2000

Experimental study is conducted to clarify the pneumatic characteristics of brake system for freight train. Empty-load and diaphragm brake systems are mainly installed in the freight trains owned by KNR(Korean National Railroad). Experimental train set is composed of sixteen freight train and one diesel locomotive that are now in use. From the experimental results, in case of commercial brake, empty-load brake system responds to the brake command more slowly than the diaphragm brake system. But, in case of release command, the response time of diaphragm brake system is shorter than that of empty-load one. In the emergency brake test, the decreasing rate of brake pipe pressure of tenth car is almost same that of decreasing rate of commercial brake service.

• Proceedings of the KIEE Conference
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• summer
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• pp.162-164
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• 2004

Electrical power peak demand of Republic of Korea is annually growing and the peak demand has occurred in the summer. It is difficult that we handle with constructing power plants and increasing generation capacity to cope with a suddenly increased demand due to the cost problem, difficulty to find the new plant site, and the spread of the NIMBY. The alternative of the above problem is to efficiently manage demand of electrical power. Accordingly, load shedding of a section of demand side management is investigated. First we surveyed a trend of research in the domestic and overseas, for load curtailment and demand response program. After reviewing several demand response programs, the future research direction for load shedding in emergency and normal operation is introduced.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.187-192
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• 2019

Hybrid power storage system with emergency power function for demand management and power outage minimizes the investment cost in the building of buildings and factories requiring emergency power generation facilities, We propose a new business model by developing technology that can secure economical efficiency by reducing power cost at all times. Normally, system power is supplied to load through STS (Static Transfer Switch), and PCS is connected to system in parallel to perform demand management. In order to efficiently operate the electric power through demand forecasting, the EMS issues a charge / discharge command to the ESS as a PMS (Power Management System), and the PMS transmits the command to the PCS controller to operate the system. During the power outage, the STS is rapidly disengaged from the system, and the PCS becomes an independent power supply and can supply constant voltage / constant frequency power to the load side. Therefore, it is possible to secure reliability through verification of actual system linkage and independent operation performance of hybrid ESS, By enabling low-carbon green growth technology to operate in conjunction with an efficient grid, it is possible to improve irregular power quality and contribute to peak load by generating renewable energy through ESS linkage. In addition, the ESS is replacing the frequency follow-up reserve, which is currently under the charge of coal-fired power generation, and thus it is anticipated that the operation cost of the LNG generator with high fuel cost can be reduced.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.37-45
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• 2013

Objective: This study describes the change of operator performance in drastic change of illumination level, and proposes an alternative method to cope with it. Background: The control standard of illumination for nuclear power plants(NPPs) is based on the set of limit criteria for maintaining a specific illumination level. However, there is a possibility to cause human errors according to the psychological and physiological influences to operators in the situation of drastic change of illumination such as SBO(Station Black Out), so a basic study is necessary to review the current approach. Method: We assessed the visual fatigue, subjective work load and task performance according to the three illumination situations(Normal Illumination, Emergency Illumination, and Drastic Change of Illumination). Result: Research finding shows that there are not significant differences in task performance between normal illumination (1,000lx level) and emergency illumination (100lx level), only if beyond the dark adaptation limit. However, subjective work load on mental demand and visual fatigue show a potential challenge to visual performance in drastic change of illumination. Conclusion/Application: Several trials can complement this challenge in NPPs by applying 3-way communication, enhancing readability of procedures, and managing the visual factors affecting the operators' performance through a Visual Environment Management Program including visual health aspects, etc.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.185-191
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• 2007

The new FMVSS 208, 213, 225 regulations include automatic suppression of airbags to prevent low-risk airbag deployment and the use of child seats with a rigid-bar anchor system. The regulations mean that children must sit in the rear seat, but do not include other specific safety measures for their protection. In the rear, restraint equipment consists of three-point shoulder/lap belts for the outside seats and a static two-point lap belt in the middle, with no additional devices such as pretensioners or load limiters; this is far from optimal for children. This study investigated injury rates using a 3-year-old-child dummy. ECE R44 sled tests used a booster, a speed of 48 km/h, and a 26- to 32-g rectangular deceleration pulse. While seated on a booster, the dummies were restrained by an adult shoulder/lap three-point belt. HIC_15 msec, Chest G and Nij were somewhat lower with an emergency locking retractor (ELR)+pretensioner+load limiter than with only an ELR or with ELR+pretensioner. However, the current seat-belt system results in injury rates that exceed the limit for OOP performance under the new FMVSS 208 regulations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.40-50
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• 2016

In order to recover the power system during the wide power outage or power failure in the power plant, black start system should be properly operated without any problem. Especially power for black start in the geographically isolated areas of electric island is supplied from small emergency start-up generator, and loads are aux systems of gas turbines such as SFC(Static frequency converter). This paper introduces the international practices to overcome the voltage drop problem with harmonics of the system having the DC output such as SFC during black start in weak feed system and analyzes the relationship between house load inputs and harmonics. By varying the house load and input of power supply, this paper identified boundaries between weak feed and strong feed power. In order to verify the theory of stable condition in weak feed power system with DC output, house load is simulated using ETAP. Additionally MATLAB was used for harmonic analysis between the load inertia moment and non load inertia moment.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.2
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• pp.57-62
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• 2018

A brush-less type synchronous generator driven by an internal-combustion engine is used for emergency electric source. These types of generators have to maintain a certain range of output voltage even under the sudden load change conditions such as full load application and removal. This paper describes a method for suppressing the output voltage of a synchronous generator that operates excessively when the load fluctuates. The method used in this paper is a feedforward control method in which the main voltage control consists of a feedback loop using a typical PID controller and the load current is detected as a disturbance element and compensated directly. A feedforward system is constructed in which the load current is regarded as disturbance, and the appropriate feedforward controller configuration and parameters are found through simulation. Finally, it can be seen through the experiment that the feedforward control is performed properly. It can be seen that the generator terminal voltage is recovered to the steady state in a short period of time as compared with the existing PID control method even when the entire load of the generator is changed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.224-232
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• 2018

According to government policy, renewable energy facility such as solar power generation is being implemented for newly constructed buildings. In recent years, the introduction of Energy Storage System (ESS) served as an emergency power for replacing an existing diesel generator has been increasing. Furthermore, in order to expand the efficacy of the ESS operation, operation in combination with renewable energy sources such as solar and wind power generation is increasing. Hence, development of the ESS operation algorithms for emergency mode as well as the peak power cut mode, which is the essential feature of ESS, are necessary. The operational scenarios of ESS need to consider load power requirement and the amount of the power generation by renewable energy sources. For the verification of the developed scenarios, tests under the actual situation are demanded, but there is a difficulty in simulating the emergency operation situation such as system failure in the actual site. Therefore, this paper proposes simulation models for the HILS(Hardware In the Loop Simulation) and operation modes developed through HILS for the ESS operated with renewable energy source under peak power reduction and emergency modes. The paper shows that the ESS operation scenarios developed through HILS work properly at the actual site, and it verifies the effectiveness of the control logic developed by the HILS.

• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.168-176
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• 2007

This study aims to provide useful information when making a decision for the environmental and economic efficiency assessment of infrastructure, based on Life Cycle Assessment(LCA). It estimates environmental cost on environmental pollutants that are possible to happen by locations and by types of emergency spillway for korean multipurpose dam, which is selected as a study case. For this purpose, this study examines the theories of LCA and Contingent Valuation Method(CVM) and suggests an analysis model of environmental cost. To apply the suggested analysis model of environmental cost for infrastructure to the case study of emergency spillway at the multipurpose dam, this study calculates environmental load on environmental pollutants that generate during life cycle, converts it to a cost to predict environmental cost, evaluates environmental economy of emergency spillway by the estimated result, and draws the optimum alternative that is environmental-friendly and economic.