• Journal of Digital Convergence
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• v.17 no.8
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• pp.105-113
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• 2019

The purpose of this study is to analyze cyber security risk modeling of critical infrastructure, draw out limitations and improvement measures. This paper analyzed cyber security risk modeling of national critical infrastructure like as electricity sector, nuclear power plant, SCADA. This paper analyzed the 26 precedent research cases of risk modeling in electricity sector, nuclear power plant, SCADA. The latest Critical Infrastructure is digitalized and has a windows operating system. Critical Infrastructure should be operated at all times, it is not possible to patch a vulnerability even though find vulnerability. This paper suggest the advanced cyber security modeling characteristic during the life cycle of the critical infrastructure and can be prevented.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.450-453
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• 1996

This research presents a new method of detecting and diagnosing faults of a power plant. Detection of characteristic wave patterns from multichannel instrumentation signals forms the basis of the proposed approach. The dynamics of 500MW drum-type boiler (Boryung coal-fired plant unit #1 and #2) and its control systems are modeled and simulated to generate diverse operation patterns and fault situations and to utilize them for the development of the fault detection algorithms. The results of the boiler system modeling and simulations show a fairly high agreement when compared with some of the actual plant performance test data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.26-30
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• 2000

In this paper, we obtain a mathematical model of a gas turbine control system from experimental data. The gas turbine in Gunsan power plant is selected as controlled system. The recursive least square algorithm is used to model the plant. For parameter estimation, plant is assumed as second order system and forgetting factor is 0.98 and the period of input and output signal period is 1sec. As a result, input and output characteristics of real system and modeling are identified.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4367-4381
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• 2023

Nuclear power plants are increasingly being equipped with digital I&C systems. Although some probabilistic safety assessment (PSA) models for the digital I&C of nuclear power plants have been constructed, there is currently no specific internationally agreed guidance for their modeling. This paper presents an initiative by the OECD Nuclear Energy Agency called "Digital I&C PSA - Comparative application of DIGital I&C Modelling Approaches for PSA (DIGMAP)", which aimed to advance the field towards practical and defendable modeling principles. The task, carried out in 2017-2021, used a simplified description of a plant focusing on the digital I&C systems important to safety, for which the participating organizations independently developed their own PSA models. Through comparison of the PSA models, sensitivity analyses as well as observations throughout the whole activity, both qualitative and quantitative lessons were learned. These include insights on failure behavior of digital I&C systems, experience from models with different levels of abstraction, benefits from benchmarking as well as major contributors to the core damage frequency and those with minor effect. The study also highlighted the challenges with modeling of large common cause component groups and the difficulties associated with estimation of key software and common cause failure parameters.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.290-294
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• 2014

PID(Proportional, Integral, Derivative) controller is the most popular process controllers in nuclear power plants. The optimized parameter setting of the process controller contributes to the stable operation and the efficiency of the operating nuclear power plants. PID parameter setting is tuned when new process control systems are installed or current process control systems are changed. When the nuclear plant is shut down, a lot of PID tuning methods such as the Trial and Error method, Ultimate Oscillation method operation, Ziegler-Nichols method, frequency method are used to tune the PID values. But inadequate PID parameter setting can be the cause of the unstable process of the operating nuclear power plant. Therefore the results of PID parameter setting should be simulated, optimized and finally verified. This paper introduces the simulation method of PID tuning to optimize the PID parameter setting and confirms them of the actual PID controller in the operating nuclear power plants. The simulation method provides the accurate process modeling and optimized PID parameter setting of the multi-loop control process in particular.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.641-646
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• 1998

In order to enhance the dynamic and interactive simulation capability of a system thermal hydraulic code for nuclear power plant, applicability of flow network models in SINDA/FLUIN $T^{™}$ has been tested by modeling feedwater system and coupling to DSNP which is one of a system thermal hydraulic simulation code for a pressurized heavy water reactor. The feedwater system is selected since it is one of the most important balance of plant systems with a potential to greatly affect the behavior of nuclear steam supply system. The flow network model of this feedwater system consists of condenser, condensate pumps, low and high pressure heaters, deaerator, feedwater pumps, and control valves. This complicated flow network is modeled and coupled to DSNP and it is tested for several normal and abnormal transient conditions such turbine load maneuvering, turbine trip, and loss of class IV power. The results show reasonable behavior of the coupled code and also gives a good dynamic and interactive simulation capabilities for the several mild transient conditions. It has been found that coupling system thermal hydraulic code with a flow network code is a proper way of upgrading simulation capability of DSNP to mature nuclear plant analyzer (NPA).

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.199-207
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• 2014

In this paper, to systematically assess the abandonment risk of main control room (MCR) fire, fire simulations with Fire Dynamics Simulator were performed and abandonment probabilities were estimated for the MCR bench-board fire of domestic reference nuclear power plant. The fire simulation scenarios performed in this study included propagating and non-propagating fires of the MCR bench-board, and the availability and unavailability of heating, ventilation, and air conditioning system (HVACS). The following results were obtained. First, temperature was the major abandonment impact factor for the MCR bench-board fire if the HVACS was available and optical density was that if the HVACS was unavailable. Second, the fire scenario contributing the MCR bench-board fire abandonment risk was identified to be only the propagating fire. Third, it was confirmed that the abandonment probability of the MCR bench-board fire for domestic reference nuclear power plant could be reduced by using the fire modeling.

• Journal of the Korean Society of Combustion
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• v.18 no.3
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• pp.44-53
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• 2013

In this study, the economic evaluation for imported coals was conducted for power plant based on thermo-dynamical performance analysis. The number of coal types considered was 1,755 imported by five power generation companies in Korea during the 2010-2012. The higher heating value (HHV) of the coals ranged 4,000-6,500 kcal/kg, mostly sub-bituminous. The 1D thermo-dynamical performance modeling was performed for a 500 MWe standard power plant using PROATES code. It was founded that the low rank coals had negative effects on the plant efficiency mainly due to the increased heat loss by moisture, hydrogen and flue gas. Based on the performance analysis, the economic performance of the coals was evaluated. The apparent price of low-rank coals tended to be significantly lower than design coal; for example, the unit price of coal with a HHV of 4,000 kcal/kg was 57% of the reference coal having 6,080 kcal/kg. Considering the negative effects leading to a decrease in the thermal performance, heating value compensation, and increased parasite load, the corrected unit cost for the coal with 4,000 kcal/kg was 90.7% of the reference coal. Overall, the cost saving by imported coals was not high as expected.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.23-28
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• 2012

The market of domestic Power Plant Generator Protection and Control System (GPCS) is narrow and required the high reliability, and technology. So, it is still operated as turn-key. In recent years, digital relays has evolved into IED can perform the control and monitoring functions without central monitoring based on IEC61850 international standards communications, and attention for advancement of smart grid and ECMS has been increased in South Korea. The increasing attention on multi-function IED, DGPS(digital generator protection system), for internal fault protection of large generator results in starting a national project in South Korea, the IED prototype development for next-generation power units. The voltage restrained overcurrent relay have been used as back-up overcurrent protection for generators. In this paper, voltage restrained overcurrent relay is one of the back-up protective factors in generator protection IED was presented. For evaluation performance of the voltage restrained overcurrent relay, the data of ATPDraw5.7p4 modeling was used.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.82-84
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• 2008

This paper presents the modeling and power quality analysis of Jeju island power system connected with wind farm, and thermal power plant. It is for indicating the influence of wind farm operation in steady and transient state in Jeju island power system during the HVDC system overhaul period. For the computer simulation, three kinds of main item are modeled, which are 67[MW] wind farm, thermal power plant and Jeju power load. To analyze the influence of the wind power generation to the Jeju power system, two kinds of simulations are carried out by using the PSCAD/EMTDC program. One is the steady state operation under the variable speed wind, and the other is the transient state operation when all of wind farms in Jeju island are disconnected from the Jeju power grid instantaneously on the rated power output. With the comparison of these results, it is useful for analyzing the power quality of Jeju power system versus wind power generation.