• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1460-1463
• /
• 1997

The aim of this paper is to suggest a design method of the model following optimal boiler-turbine H.inf. control system using genetic algorithm. This boiler-turbine H.inf. control system is designed by applying genetic algortihm with reference model to the optimal determination of weighting functions and design parameter .gamma. that are given by Glover-Doyle algornithm whch can design H.inf. contrlaaer in the sate. space. The first method to do this is ghat the gains of weightinf functions and .gamma. are optimized simultaneously by genetic algroithm. And the second method is that not only the gains and .gamma. but also the dynamics of weighting functions are optimized at the same time by genetic algonithm. The effectiveness of this boiler-turbine H.inf. control system is verified and compared with LQG/LTR control system by computer simulation.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.4
• /
• pp.295-303
• /
• 2001

The demand for steam generators is increasing in industrial systems in which the design strategy should be implemented for safe and efficient operation of steam generators. It is, however, difficult to design a controller by the conventional method because of the nonlinear dynamics of the steam generator and influences by the set value of disturbance. This paper presents an automatic parameter optimization technique for a multivariable fuzzy controller using evolutionary strategy, At first, we use the steady state information such as a steady state gain matrix(SSGM) and a relative gain matrix(RGM). We can obtain much information on the control inputs and the outputs of the boiler-turbine system from the matrices. In order to determine the structure of the controller by using RGM and SSGM, the fuzzy rules are trained by evolutionary strategy. The good performance of the proposed multivariable fuzzy controller is verified through simulations.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1670_1671
• /
• 2009

산업경제구조의 변화로 경험이 풍부한 전문가들이 은퇴하고 경험이 적은 직원들이 그들의 업무를 대신하는 구조로 조직이 변화하고 있다. 동시에 녹색성장시대의 도래로 화석연료를 사용하는 설비에 대한 투자가 줄면서 점차로 노후화되는 경향을 보이고 있어 불필요한 운전 과도현상에서 기인된 극단적인 손상은 설비자체 및 전력공급계통 전체에 치명적이라고 할 수 있다. 따라서 석탄화력발전소 제어 시스템은 이러한 사안들을 안정적으로 이끌어 나가기 위한 중요한 요소로 저비용 고효율 발전소 유지를 위해 중점적으로 발전시켜 나가야 할 부분이다. 본 논문은 석탄화력발전소의 주구성요소인 보일러와 터빈을 제어하는 마스터 제어기의 복잡한 로직을 모델 기반의 간단한 로직으로 개발하여 시뮬레이션 한 결과를 실제 발전소에 적용하기 위한 내용을 기술하였다. 실제 발전소는 많은 위험요소들을 안고 있기 때문에 시뮬레이션에서 나타나는 급격한 제어동작을 수용할 수 없을 경우도 있으며, 실제 다른 많은 변수들이 제어불안정 요소로 작용할 수 있다. 차후 실제 적용한 결과는 예측제어의 사용과 같은 제어시스템 향상을 위한 개발과 운영효율 향상에 사용될 것이다. 튜닝 과정에서의 연구결과는 시간절약과 제어부분 결함제거 등 직원들의 전문지식 향상 등에 도움을 주게 될 것이다.

• Proceedings of the KIEE Conference
• /
• 2008.10b
• /
• pp.403-404
• /
• 2008

자원의 고갈과 각종 환경규제 및 정부의 전력거래 방침 등으로 인해 점점 발전소에서는 전력 계통에 대한 신뢰도 및 전기품질을 유지하기가 어려워지고있다. 발전소의 부하대별 주요 운전 설계값은 효율과 바로 직결되는 사항으로 각 부하별로 온도와 압력 등 운전설계값을 최적의 상태로 유지하는 것은 발전소 수명과 발전효율, 전력거래 등에 있어 중요한 요소들이다. 전력시장에 진입하는 발전소는 전력계통의 갑작스런 불안성 상황이나 전력거래소 요청시 경사변동폭, 출력변통율, 무효전력 출력, 자동발전제어, 주파수조절량 확보 등을 수행할 수 있어야 한다. 본 논문에서는 고급공정제어기를 이용하여 운전설계계값을 효과적으로 제어 하면서 기존의 제어로직보다 전력계통상에서 요구되는 발전기 출력을 최대한 신속히 제어하는 과정을 기술하였다. 우선 보일러 마스터와 터빈 마스터, 급수 마스터로 구성된 제어로직을 설계한 뒤 이들 마스터에 대한 발전기 출력, 주증기 압력, 기수분리기 출구온도 각각의 영향을 모델링 기법을 이용하여 적합한 모델을 구했다. 각각의 모델을 고급공정제어기에 적용하고 발전기 출력제어에 대한 기존의 발전소 응답보다 좀 더 효율적이고 실제적용이 가능한 결과를 얻을 수 있도록 튜닝을 시행했으며 그 과정과 결과를 기술했다.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2455-2457
• /
• 2000

In this paper, it is proposed a neural adaptve control algorithm for boiler-turbine system. Control inputs are constructed using RBF Neural networks and variable structure inputs are added to improve the robustness. This proposed algorithm does not need the information about parameters and can assure the robustness under the output disturbance and parameter perturbations. The results of computer simulations is presented to verify the efficiency of the proposed algorithm.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.4
• /
• pp.302-306
• /
• 2006

The improvement of load following operation of the thermal power plant is influenced to the electrical quality. Analysis of boiler, turbine, and governor system, and the study of control algorithm are necessarily preceded. The thermal power plant is operated by various control systems. In the case of faulty governor system, it takes long days to solve the problem and impossible to repair the mechanism without outage. A non-planned outage is taken into consideration because of economical power production. The paper introduces the followings; In case of system-frequency drop during long term, at 500MW thermal power plant, the generator output was drop. To clear this problem, the control logic is modified with analysis of trend and control algorithm. As a result system frequency drop is prevented during the long tenn and the electric grid operation is improved.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.2
• /
• pp.157-164
• /
• 2017

A parallel slide gate valve (PSGV) is located between the heat recovery steam generator (HRSG) and the steam turbine in a combined cycle power plant (CCPP). It is used to control the flow of steam and runs with repetitive operations such as startups, load changes, and shutdowns during its operation period. Therefore, it is necessary to evaluate the fatigue damage and the structural integrity under a large compressive thermal stress due to the temperature difference through the valve wall thickness during the startup operations. In this paper, the thermal-structural analysis and the fatigue life evaluation of a 16-inch PSGV, which is installed on the HP steam line, is performed according to the fatigue life assessment method described in the ASME B&PVC VIII-2; the method uses the equivalent stress from the elastic stress analysis.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.2
• /
• pp.199-209
• /
• 1990

In this paper, a multivariable robust controller for a boiler-burbine system is designed by using a modified LQG/LTR method. From the known nonlinear dynamic model, a linearized model is obtained with the saturations at both input magnitude and input varying rate. The modeling error is analyzed at various operation points. A new dynamics augmentation method in the LQG/LTR method is suggested which can be applied to LQG/LTR method to reject the input and output disturbances and to follow reference inputs under modeling errors. The good performance of the designed controller is shown by simulations in various conditions.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.441-445
• /
• 1997

In this paper, we suggest a design scheme of receding horizon predictive control(RHPC) for boiler-turbine systems whose dynamics are given in nonlinear equations. RHPC is designed for linear state space models which are obtained at a nominal operating point of the boiler-turbine system. In this consideration, the boiler is operated in a sliding pressure mode, in which the reference value of drum pressure is changing according to the electrical power generation. The reference values of the system outputs are prefiltered before they are fed to the RHPC in order to compensate the linearization errors. Simulation results show that the proposed controller provides acceptable performances in both of the cases of 'steep and small changes' and 'slow and large changes' of power demand and yields the effect of modest coordination of conventional PID schemes such as boiler-following and turbine-following control.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.446-448
• /
• 1997

The aim of this paper is to introduce a method designing the optimal model following boiler-turbine control system using genetic algorithms. This boiler-turbine control system is designed by applying genetic algorithms with reference model to the optimal determination of weighting matrices Q, R that are given by LQ regulator problem. These weighting matrices are optimized simultaneously in the search domain selected adequately. The effectiveness of this boiler-turbine control system is verified by computer simulation.