• 조명전기설비학회논문지
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• 제29권4호
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• pp.102-107
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• 2015

In this paper, the generator control system by using PSCAD/EMTDC was modeled and several faults simulation were performed. The generator control system is composed of generator, turbine, exciter and governor. The parameters of generator control system model were obtained from field power plant. And then, the various transient phenomena through obtained several signal of developed modeling were analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.121-122
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• 2006

The generator system modeling for large generator protection is a significant portion for the analysis of installed apparatus and development of domestic production. In this paper, MATLAB EMTP/ATP, and PSCAD/EMTDC are used to simulate the transient phenomenon for the faults of generator.

• 한국컴퓨터정보학회논문지
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• 제3권2호
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• pp.99-104
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• 1998

본 논문에서는 다단 논리회로의 고장을 완벽하게 검출할 수 있는 테스트 패턴 생성기를 설계하였다. 이 테스트 기법은 테스트 패턴 생성 논리회로를 사용하여 생성하였다. 생성된 테스트 패턴은 기존의 전체 테스트 방법에 비해 패턴을 크게 감소시켰다. 이 테스트패턴 생성기는 다단 논리회로에서의 모든 고장을 검출할 것으로 본다. 여러 가지 I.C 테스트 방법 중에서 어떤 방법을 선택할 것인지는 고장검출 속도에 영향을 준다. 가장 중요한 것은생산단가이며 설계된 테스트 패턴 생성기는 저가형이다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3283-3292
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• 2022

Based on the Deep Q-Network(DQN) algorithm of reinforcement learning, an active fault-tolerance method with incremental action is proposed for the control system with sensor faults of the once-through steam generator(OTSG). In this paper, we first establish the OTSG model as the interaction environment for the agent of reinforcement learning. The reinforcement learning agent chooses an action according to the system state obtained by the pressure sensor, the incremental action can gradually approach the optimal strategy for the current fault, and then the agent updates the network by different rewards obtained in the interaction process. In this way, we can transform the active fault tolerant control process of the OTSG to the reinforcement learning agent's decision-making process. The comparison experiments compared with the traditional reinforcement learning algorithm(RL) with fixed strategies show that the active fault-tolerant controller designed in this paper can accurately and rapidly control under sensor faults so that the pressure of the OTSG can be stabilized near the set-point value, and the OTSG can run normally and stably.

• Journal of Power Electronics
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• 제7권2호
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• pp.89-96
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• 2007

This paper deals with the transient performance of an induction generator in a wind power plant. An induction generator and grid equipment may be damaged when a sudden disturbance occurs, for example, a sudden disconnection from the utility grid. The reasons for this are over-voltage and over speed. This paper analyzes this phenomena using PSCAD/EMTDC and coincides with its corresponding mathematical equation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.819-821
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• 1998

This paper deals with a method or a residual generation for fault isolation in a centrifugal pump with a water circulation system, driven by a speed controlled dc motor. It is based on parity relations derived from the moving-average model of the system and is used to identify sensor faults and two possible brush and impeller faults, where the former is dealt with additive faults, while the latter characterized as discrepancies between the nominal and actual plant parameters of the system is modelled by multiplicative faults. We will represent the propagation of this uncertainty to the model matrices by the approximate handling of partial derivatives of polynomials. With multiplicative faults, the transformation matrix implemented in the residual generator are calculated on-line. The simulation studies demonstrate that small changes of the system can be detected and diagnosed by using the method.

• 전기학회논문지
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• 제58권2호
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• pp.356-362
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• 2009

The ELectromagnetic Core Imperfection Detector (EL-CID) test was performed on a small generator in the laboratory and a gas turbine generator in the field to assess the fault condition of generator stator core. Artificial defects with six different sizes were introduced in the small generator. The scan results on six defects show a very large increase in the magnitude of fault current compared to that obtained with a healthy core. After the stator core heats up, a thermal imaging camera was used to detect hot spot on the inner surface of the core for comparison. Several faults were found during inspection of the gas turbine generator with the EL-CID. It has been shown that the existence of a fault can be determined by monitoring the magnitude of fault current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.326-328
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• 2003

In this paper, in order to generator protection from a electrical fault was occurred while a generator is operated, principles of existing generator protection algorithm is examined and analyzed. and a new generator protection algorithm was developed. also, during a generator operation, Algorithm, an analysis for the basic principle of protective relay to general faults, was developed. This paper, generator was simple analyzed on the assumption that three-phase winding and observe the IEEE std.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1029-1039
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• 2013

To avoid undesirable disconnection of healthy wind generators (WGs) or a wind power plant, a WG protection relay should discriminate among faults, so that it can operate instantaneously for WG, connected feeder or connection bus faults, it can operate after a delay for inter-tie or grid faults, and it can avoid operating for parallel WG or adjacent feeder faults. A WG protection relay based on the positive- and negative-sequence fault components is proposed in the paper. At stage 1, the proposed relay uses the magnitude of the positive-sequence component in the fault current to distinguish faults requiring non-operation response from those requiring instantaneous or delayed operation responses. At stage 2, the fault type is first determined using the relationships between the positive- and negative-sequence fault components. Then, the relay differentiates between instantaneous operation and delayed operation based on the magnitude of the positive-sequence fault component. Various fault scenarios involving changes in position and type of fault and faulted phases are used to verify the performance of the relay. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. Results indicate that the relay can successfully distinguish the need for instantaneous, delayed, or non-operation.

• 한국정밀공학회지
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• 제19권4호
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• pp.168-178
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• 2002

The CNC machine toots has two kinds of fault. One is the fault due to degraded parts and the other is the fault due to operation disability. The phenomena of degradation is predictable but the operational fault is unpredictable because it occurred without any warning. The major faults of CNC machine tool are operational faults which are charged over 70%. This paper describes the model of remote service and the intelligent fault diagnosis system to diagnosis operational faults of CNC machine tools. To generalize fault diagnosis, two diagnosis models such as SF(Switching Function) and SSF(Step Switching Function) are proposed. The SF is static model and SSF is dynamic model for expression of fault. The SF and SSF model can be generated using SFG(Switching Function Generator) which is developed in this research. The three major operational faults such as emergency stop error, cycle start disability and machine ready disability are applied to experiment of fault modeling. To remote service of faults fur CNC machine tool, the web server and client system based internet are proposed as the suitable environment. The developed two technologies are implemented with the internal function of open architecture controller. The implemental results for two technologies are presented to validate the proposed scheme.