• 조명전기설비학회논문지
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• 제13권4호
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• pp.47-55
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• 1999

본 논문에서는 반복적 방법을 이용하여 열교환기 시스템의 온도제어를 위한 제어기를 구성하였다. 쌍선형 시스템으로 표현되는 열교환기 시스템에 대하여 최적이론을 적용하기 위하여 반복적 방법이 가능하도록 시스템을 구성하였으며, 상태궤환 제어기의 설계를 위하여 이 시스템의 상태인 증기온도를 추정하기 위한 확장 칼만 필터를 제시하였다. 또한 설계된 제어기를 화력발전소의 과열기 시스템의 온도제어에 적용하였고, 컴퓨터 시뮬레이션을 통하여 추정값이 외부입력의 변동 하에서 상태값에 적절하게 추종됨을 확인하였으며, 출구의 증기온도가 이러한 외부입력의 변동 하에서 주어진 목표치고 추종함을 보였다.

• 대한전기학회논문지
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• 제40권1호
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• pp.120-127
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• 1991

The purpose of this study is to develop a fault detection and diagnosis scheme that can monitor process fault and instrument fault of a steam generator. The suggested scheme consists of a Kalman filter and two bias estimators. Method of detecting process and instrument fault in a steam generator uses the mean test on the residual sequence of Kalman filter, designed for the unfailed system, to make a fault decision. Once a fault is detected, two bias estimators are driven to estimate the fault and to discriminate process fault and instrument fault. In case of process fault, the fault diagnosis of outlet temperature, feed-water heater and main steam control value is considered. In instrument fault, the fault diagnosis of steam genrator's three instruments is considered. Computer simulation tests show that on-line prompt fault detection and diagnosis can be performed very successfully.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.310-315
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• 1997

System-Integrated Modular Advanced Reactor (SMART), where major primary components such as modular helical steam generator and self regulating pressurizer are integrated into reactor vessel, is currently under development. The pressurizer is designed to control the primary pressure mainly with partial pressure of nitrogen gas and to maintain the fluid temperature as low as possible for the purpose of minimizing steam contribution. The steam generator (SG) is designed to produce super-heated steam inside tube at power operation. Because the in-vessel pressurizer and in-vessel SG are classified as the characteristic components of SMART, it is important to perform a steady state calculation of these components in order to evaluate the adoption of these components. A steady state analysis of the in-vessel pressurizer and in-vessel SG has been performed under normal power operation and the results show an acceptable performance of the components.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.837-841
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• 2001

Almost all power plant boiler has temperature distribution nonuniformity problem in heat transfer tube flow path. It can cause hot spot damage of superheated or reheated heat transfer section and reduce maintenance schedule when nonuniformity is severe. There are two solutions for improvement temperature nonuniformity. one is change of gas flow distribution of gas path and the other is contorl steam flow in tube bank. Of course, first method is very difficulty to apply but second method is'nt. In this paper, control steam flow is used to solve temperature nonuniformity of power plant boiler.

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.11-18
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• 2018

A high efficiency integrated reforming system for improving the efficiency of the 5 kW PEMFC system used as the back up power of building was studied. The separated reforming system consisted of three parts - A steam reformer with two stage concentric circular shape, a heat exchanger type steam generator and a CO shift reactor. Temperature and steam carbon ratio (SCR) were control variables during operation. The operating conditions were optimized based on the thermal efficiency of the steam reformer as reformate gas composition changes at different temperature. In experiments, water was fully vaporized in the steam generator up to SCR 3.5 and the maximum thermal efficiency was achieved at the operating temperature around $700^{\circ}C$ in the steam reforming reactor. With the results of the separated reforming system research, we improved the shape of high efficiency integrated reformer. The performance evaluation of the integrated reformer was based on optimized operating conditions in SCR 3.5. As a result, the developed integrated reforming system maintained an efficiency of 76% and constant performance over 3,000 hours.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2699-2708
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• 2020

Helical-coil steam generator (HCSG) technology is a major design candidate for small modular reactors due to its compactness and capability to produce superheated steam with high generation efficiency. In this paper, we investigate the feasibility of the passively autonomous power maneuvering by coupling the 3-D transient multi-physics of a soluble-boron-free (SBF) core with a time-dependent HCSG model. The predictor corrector quasi-static method was used to reduce the cost of the transient 3-D neutronic solution. In the numerical system simulations, the feedwater flow rate to the secondary of the HCSGs is adjusted to extract the demanded power from the primary loop. This varies the coolant temperature at the inlet of the SBF core, which governs the passively autonomous power maneuvering due to the strongly negative coolant reactivity feedback. Here, we simulate a 100-50-100 load-follow operation with a 5%/minute power ramping speed to investigate the feasibility of the passively autonomous load-follow in a 450 MW_th SBF PWR. In addition, the passively autonomous frequency control operation is investigated. The various system models are coupled, and they are solved by an in-house Fortran-95 code. The results of this work demonstrate constant steam temperature in the secondary side and limited variation of the primary coolant temperature. Meanwhile, the variations of the core axial shape index and the core power peaking are sufficiently small.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.85-94
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• 2016

An experimental study is conducted for unsteady wet steam flow in a four-stage low-pressure test steam turbine. The measurements are carried out at outlets of the last two stages by using a newly developed fast response aerodynamic probe. This FRAP-HTH probe (Fast Response Aerodynamic Probe - High Temperature Heated) has a miniature high-power cartridge heater with an active control system to heat the probe tip, allowing it to be applied to wet steam measurements. The phase-locked average results obtained with a sampling frequency of 200 kHz clarify the flow characteristics, such as the blade wakes and secondary vortexes, downstream from the individual rotational blades in the wet steam environment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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• pp.1295-1298
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• 2003

The steam generator level in a PWR is very difficult to control particularly at low power. And the constant control gain and time value are not adaptive in steam generator level controller. In normal operation constant control gain and time value have no problem. But there is problem at low power. So variable control gains based on the temperature are required. The best control gain is decided by the experienced knowledge. A fuzzy gain tuner is used for the gain tuning. In the design of fuzzy gain-tuner processing, the experienced knowledge is employed for making fuzzy rules.

• 드라이브 ㆍ 컨트롤
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• 제16권4호
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• pp.93-100
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• 2019

Nuclear and thermal power plants must provide the turbines with an appropriate degree of high temperature and high pressure steam, to produce the optimum electricity. Additionally, in the event of system and power system failure during electrical production, the steam is immediately disabled, to protect the turbines and generators rotating at high speed. The plant thus uses a special steam control valve system for turbine control, which is opened by force of the hydraulic servo actuator and closed by a large steel spring force. In this study, the causes of failure of the turbine control valve system, a key device of the power plants, were analyzed, and the causes of failure were improved relative to reliability of the equipment.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.412-414
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• 2005

In this paper, we present a method of fuzzy controller design for the power plant superheater in the form of bilinear system. For the steam temperature control, the input variables are constructed by the area of difference between the profiles estimated from bilinear observer and reference profiles, and the time rate of change. We estimate the control rules by T. Takagi and M. Sugeno's fuzzy model. The feasibilities of the suggested method are illustrated via the computer simulation result.