전력계통의 전압안정도향상을 위한 감시제어시스템 개발

이현철(Hyun-Chul Lee),정기석(Ki-Suk Jeoung),박지호(Ji-Ho Park),백영식(Young-Sik Baek) 대한전기학회 2013 전기학회논문지 Vol.62 No.4

This paper was developed a monitoring and control system to use reactive power control algorithm. This algorithm could be improved voltage stability in power system. This method was controlled the voltage for stability improvement, effective usage of reactive power, and the increase of the power quality. PMS(Power Management System) has been calculate voltage sensitivity, and control reactive power compensation device. The voltage control was used to the FACTS, MSC/MSR(Mechanically Switched Capacitors/Reactors), and tap of transformer in power system. The reactive power devices in power system were control by voltage sensitivity ranking of each bus. Also, to secure momentary reactive power, it had been controlled as the rest of reactive power in the each bus. In here, reactive power has been MSC/MSR. The simulation result, First control was voltage control as fast response control of FACTS. Second control was voltage control through the necessary reactive power calculation as slow response control of MSR/MSR. Third control was secured momentary reactive reserve power. This control was method by cooperative control between FACTS and MSR/MSC. Therefore, the proposed algorithm was had been secured the suitable reactive reserve power in power system.

Application of Fuzzy PI Control Algorithm as Stator Power Controller of a Double-Fed Induction Machine in Wind Power Generation Systems

Gyo-Bum Chung,Jaeho Choi 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.1

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

Improvement in Active Power Control Methods for a Wind Farm Based on Modified Wind Turbine Control in Danish Grid Codes

JunBo Sim,Il-Keun Song,Yongseung Lee,Hak-Ju Lee,Yun-Hyuk Choi 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

The importance of power system stability has been emphasized with an increase of wind energy penetration in the power system. Accordingly, the guarantee on various control capabilities, including active and reactive power control of wind farms, was regarded as the most important aspect for the connection to the grid. To control the wind farm active power, the wind farm controller was introduced. The wind farm controller decides the power set points for each wind turbine generating unit and each wind turbine generating unit controls its power according to the set points from the wind farm controller. Therefore, co-relationship between wind farm controller and wind turbine controllers are significantly important. This paper proposes some control methods of wind farm active power control based on modified wind turbine control for power system stability and structures to connect wind turbine controllers to wind farm controller. Besides, this paper contributes to development of control algorithm considering not only electrical components but also mechanical components. The proposed contributions were verified by full simulation including power electronics and turbulent wind speed. The scenario refers to the active power control regulations of the Eltra and Elkraft system in Denmark.

Power Smoothening Control of Wind Farms Based on Inertial Effect of Wind Turbine Systems

Thanh Hai Nguyen,Dong-Choon Lee,Jong-Ho Kang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.3

This paper proposes a novel strategy for attenuating the output power fluctuation of the wind farm (WF) in a range of tens of seconds delivered to the grid, where the kinetic energy caused by the large inertia of the wind turbine systems is utilized. A control scheme of the two-level structure is applied to control the wind farm, which consists of a supervisory control of the wind farm and individual wind turbine controls. The supervisory control generates the output power reference of the wind farm, which is filtered out from the available power extracted from the wind by a low-pass filter (LPF). A lead-lag compensator is used for compensating for the phase delay of the output power reference compared with the available power. By this control strategy, when the reference power is lower than the maximum available power, some of individual wind turbines are operated in the storing mode of the kinetic energy by increasing the turbine speeds. Then, these individual wind turbines release the kinetic power by reducing the turbine speed, when the power command is higher than the available power. In addition, the pitch angle control systems of the wind turbines are also employed to limit the turbine speed not higher than the limitation value during the storing mode of kinetic energy. For coordinating the de-rated operation of the WT and the storing or releasing modes of the kinetic energy, the output power fluctuations are reduced by about 20%. The PSCAD/EMTDC simulations have been carried out for a 10-MW wind farm equipped with the permanent-magnet synchronous generator (PMSG) to verify the validity of the proposed method.

AC Cycles 가변을 이용한 PTC 발열체의 전력제어

공재웅,이영주,김두영,Gong, Jae-Woong,Lee, Young-Joo,Kim, Doo-Young 한국융합신호처리학회 2011 융합신호처리학회 논문지 (JISPS) Vol.12 No.4

기존 발열체의 전력제어는 On-Off 제어, 위상제어, PWM 제어를 사용해왔다. 최근 개발된 PTC 발열체를 기존의 방법으로 전력제어를 하였을 경우, 온도를 정밀하게 제어하지 못하고 인체에 유해한 전자파가 발생한다. 본 논문은 AC Cycles 가변을 이용한 PTC 열선의 전력 제어를 제안한다. 이것은 N개의 교류 cycle을 전력 제어의 단위로 간주하여, 각 cycle 마다 On-Off 여부를 결정하여 N cycles 내의 on-cycle 을 랜덤하게 배치하여 지속적으로 AC전력제어방법이다. 이 때 최소 전력량은 1/N이 되고 최대 전력량은 1이 되며 설정 값에 따라 on cycle의 수를 설정하여 N개의 단계로 일정하게 전력을 제어할 수 있다. PTC 열선과 온도센서를 사용한 발열 시스템에서 제안한 전력제어 방식이 전자파 발생과 온도제어 특성에서 우수함을 MATLAB simulation과 실험 및 측정을 통하여 확인하였다. The power control of the existing heating element has been using the On-Off control, phase control, and PWM control. In case of controlling power PTC heating element developed recently with the existing method, the temperature is unable to be precisely controlled or the harmful electromagnetic wave to human body is generated. In this paper, We suggest the power control of PTC heating cable using variable AC Cycles. This regards the AC cycle of N as the unit of the power control. It determines On-Off for each cycle. It is the AC power control method in which it arranges the on-cycle in N cycles in the random and it supplies the current continuously. At this time. the minimal electric power amount becomes 1/N. The maximum current amount becomes 1 and sets up the number of on cycles according to the set value and can control the electric power with the step of N consistently. In the PTC heating system, we show that proposed power control method is superior in the EMI and temperature control property using MATLAB simulation, experiments and measurements.

석탄화력발전소 보일러 연료제어 알고리즘과 분산제어시스템의 개발

임건표(Gun-Pyo Lim),이흥호(Heung-Ho Lee) 대한전기학회 2013 전기학회논문지 P Vol.62 No.1

This paper is written for the development and application of boiler fuel control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. Fuel control algorithm has the upper algorithm and it is boiler master control algorithm that controls the fuel, feed water, air by generation output demand. Generation output demand by power load influences fuel control. Because fuel can not be supplied fast to the furnace of boiler, fuel control algorithm was designed adequately to control the steam temperature and to prevent the explosion of boiler. This control algorithms were coded to the control programs of distributed control systems which were developed domestically for the first time. Simulator for coal-fired power plant was used in the test step. After all of distributed control systems were connected to the simulator, the tests of the actual power plant were performed successfully. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

전력시스템의 부하주파수 제어를 위한 뉴로-퍼지제어기 설계

손태훈,김상효 동의공업대학 2000 論文集 Vol.26 No.1

The load frequency control of power system is one of important subjects in view of system operation and control. That is, even though the rapid load disturbances were applied to the given power system, the stable and reliable power should be supplied to the users, converging unconditionally and rapidly the frequency deviations and the tie-line power flow ones of each area into allowable boundary limits. Nonetheless of such needs, if the internal parameter perturbation and the sudden load variation were given, the unstable phenomena of power system can be often brought out because of the large frequency deviation and the unsuppressible power line one. Therefore, it is desirable to design the robust power system controller which can stabilize effectively the given power system as soon as possible, In this paper the robust neuro-fuzzy controller was proposed and applied to control of load frequency over multi-area power system. The architecture and algorithm of a designed NFC(Neuro-Fuzzy Controller) were consist of fuzzy controller and neural network for auto tuning of fuzzy controller. The adaptively learned antecedent and consequent parameters of membership functions in fuzzy controller were acquired from the steepest gradient method for error-back propagation algorithm.

Application of Fuzzy PI Control Algorithm as Stator Power Controller of a Double-Fed Induction Machine in Wind Power Generation Systems

정교범,최재호 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.1

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

Fuzzy logic based improved Active and Reactive Power control operation of DFIG for Wind Power Generation

J.P. Mishra,Debirupa Hore,Asadur Rahman 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The fuzzy-controllers are designed to tune along with the conventional PI-controllers for the vector control of active and reactive power of a wind-turbine driven DFIG under varying wind speed operation to optimize the power generation at specified power-factor. Initially, stator-flux-oriented vector control scheme is implemented using tuned active and reactive power PI-controllers for the rotor-side-converter. Then the fuzzy-controllers are also tuned along with conventional PI-controllers for the generated active power to track more precisely the reference power at specified power-factor in both sub-synchronous and super-synchronous modes of operations. The grid-side-converter is controlled in grid-voltage-oriented reference frame using dc-link voltage PI-controller. Hysteresis current controlled based PWM switching of both rotor-side and grid-side converters ensure fast and accurate control of active and reactive power. Simulation results under varying wind conditions reveal that the additional fuzzy-controller improves the performance of variable speed wind power generating system using DFIG.

Direct Parallel and Hybrid Power Control Scheme of a Low-Power PV and Piezoelectric Energy Harvesting Module

Lee Dong-Hee 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

This paper presents a novel direct parallel power control scheme with independent current paths for the proposed hybrid energy-harvesting system that consists of a low-power photovoltaic panel, a piezoelectric harvesting module, and an energy storage system. A battery is connected to store the generated power from the two renewable power sources to provide a continuous power supply for the users. The designed power converter controls both battery state and power supply without any power conditioning system. To achieve this, a low-power DC–DC converter with battery charging function and control algorithm is designed for the hybrid power source. Therefore, in the proposed system, no additional battery charge controller is required. To control the battery, however, an additional current sensor to detect the battery power is simply added to each DC–DC converter. In the proposed power control scheme and controller, each power input, output, and the combined power fl ow are connected with neither communication protocols nor additional controller. Moreover, the converters can adjust the supplied power for parallel power-sharing. For maximum output current protection in each converter and constant current control for the battery, a hybrid power connection and its related current path are also proposed in this paper. The eff ectiveness of the proposed hybrid power system and the direct parallel power control scheme was verifi ed through experiments.