• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.70-75
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• 2014

TMR(triple modular redundant) digital excitation system with simulator is developed for tuning optimal control parameters during commissioning test and coping with system faults rapidly. A new system which mocks up virtual generator, turbine, grid can simulate as if excitation system is connected to a real generator system by setting four switches. The maintenance crew using the simulator is able to test perfectly the phase controller rectifiers, field breaker, sequence relays as well as TMR controller of the excitation system. Commissioning and performance results about the excitation system with simulator is discussed. The trial product was installed and operated at a 500MW thermal power plant after the commissioning test.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1660_1661
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• 2009

The excitation system for nuclear emergency diesel generator has been developed and is commercially operating now. The characteristics are triple modular redundant controllers, double redundant rectifiers and digital system, comparing the existing(and removed) system.

• ETRI Journal
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• v.39 no.4
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• pp.605-613
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• 2017

Simulated fault injection (SFI) is widely used to assess the effectiveness of fault tolerance mechanisms in safety-critical embedded systems (SCESs) because of its advantages such as controllability and observability. However, the long test time of SFI due to the large number of test cases and the complex simulation models of modern SCESs has been identified as a limiting factor. We present a method that can accelerate an SFI tool using a checkpoint forwarding (CF) technique. To evaluate the performance of CF-based SFI (CF-SFI), we have developed a CF mechanism using Verilog fault-injection tools and two systems under test (SUT): a single-core-based co-simulation model and a triple modular redundant co-simulation model. Both systems use the Verilog simulation model of the OpenRISC 1200 processor and can execute the embedded benchmarks from MiBench. We investigate the effectiveness of the CF mechanism and evaluate the two SUTs by measuring the test time as well as the failure rates. Compared to the SFI with no CF mechanism, the proposed CF-SFI approach reduces the test time of the two SUTs by 29%-45%.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.958-959
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• 2006

For the life extension of Jeju thermal power plant, digital PWM excitation system was replaced by KEPRI. This system consist of TMR(Triple Modular Redundant) controller, dual PWM power inverter for field current control and MMI etc. The Performance test during the commissioning verified the reliability of digital PWM excitation system and recently, this system has been operated successfully.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.689-694
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• 2014

An SPLC (Safety Programmable Logic Controller) must be designed to meet the highest safety standards, IEEE 1E, and should guarantee a level of fault-tolerance and high-reliability that ensures complete error-free operation. In order to satisfy these criteria, I/O modules, communication modules, processor modules and bus modules of the SPLC have been configured in triple or dual modular redundancy. The redundant modules receive the same data to determine the final data by the voting logic. Currently, the processor of each rx module performs the voting by deciding on the final data. It is the intent of this paper to prove the improvement on the current system, and develop a voting system for multiple data on a system bus level. The new system bus protocol is implemented based on a TCN-MVB that is a deterministic network consisting of a master-slave structure. The test result shows that the suggested system is better than the present system in view of its high utilization and improved performance of data exchange and voting.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.731-733
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• 1999

Distributed Control System has been used for large scale and critical system control such as aerospace industries, chemical and power plant and so on. It is very impotant factors for design of the control system to be reliable and fault-tolerant. These control systems have backup or redundant processing modules for minimizing the time of failure and improving reliability. But such methods have changeover duration from faulty module to healthy one. During that interval, feedback control loop raises bumper and performance of the system become worse. TMR(Triple Modular Redundancy) control system is one of the best reliable ones that can overcome such a mortal drawback. This paper analyzes the components of TMR system functionally and proposes practical and cost effective configuration method for turbine control of thermal power plant.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.305-309
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• 2003

In recent large power plants, the excitation system has the static type, which is characterized by the fast response to increase the transient stability. The high capacity excitation systems developed in KEPRI is either a hot back-up, hybrid hot back-up (analog + digital) or triple modular redundant digital type, both well proven by actual tests and applied in commercial operation. The large excitation systems have been developed taking into consideration the parameters of large scale power plants, resulting in high costs and subsequently are supplied at higher prices. When used at small sized power plants, the cost impact is relatively high. As a countermeasure to such a situation, KEPRI has recently developed a reliable, miniature digital excitation system, which is one-board type, convenient and adequate for low-price, small-sized (0.5MW∼200MW) power plants.