• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1155-1157
• /
• 1999

The UPFC is known to have the ability to control both the real power flow and the reactive power flow. [1],[2] The power flow in the system is heavily related with the system security. [4] This paper deals with the operation of the UPFC to increase the power system security. The concept of the power system security is verified and the index to indicate the power system security level is suggested. And the algorithm to find the optimum operation point of the UPFC improving the system security level is presented.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.53 no.2
• /
• pp.89-93
• /
• 2004

Supervisory Control And Data Acquisition(SCADA) of electric power system refersto the system that displays, monitors and executes the control commands for remote electric power system. KNR's existing electric power control system is built on UNIX platform such that it costs more for system construction, and people with UNIX skills can only be an operator who controls and manages the system. Moreover, since the system is mainly operated in local offices, system operators must communicate with local operators to investigate the cause of the accident and react the accident every time the system fails. As a new integrated SCADA system is constructed, establishment of small-unit electric power control system, that alters local electric power control system in designated stations, is required. In this study, the electric power control system, which accommodates all functions of UNIX-based SCADA system and facilitates operation and even maintenance for local operators, is to be developed. In order to develop small-unit electric power control system, the industrial automation program, "Cimon", is used. The small-unit electric power control system that accommodatesRTU and newly installed electronic switchboard is being developed and tested at Chulam station of KNR.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.79-84
• /
• 1990

Analog systems could not fully deal with instrumentation and control facilities in power plants since these facilities have become more and more complex on account of various needs for large power generation capacity highly cost effective operation to conserve energy and operation management to prevent pollution. Digitalizations of control device and augmentations of control informations increased the necessity of fiber optic data networks which have excellent noise immunity and high quality wide-band with information transfer capability. The goal of this study is to offer a fiber optic data-way system which has high reliabilities, high data transmission rates and small cable ducts with large transmission capacities for the instrumentation and control of power plants.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.1260-1262
• /
• 2004

Direct Load Control(DLC) system is a load management program for stablization of electric power supply-demand. It is a series of acts limiting the demand of selected demand side at peak load or other time periods. Recently, power supply-demand instability due to dramatic increase in power usage such as summertime air-conditioning load has brought forecasts of decrease in power supply capability. Therefore heightening the load factor through systematic load management, in other words, Direct Load Control became necessary. By examining the composition and operation of the DLC system, this paper provides conceptional understanding of the DLC system and help in system research.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.754-760
• /
• 2011

In the DC traction system, a large load current of electric railcar leads to a voltage drop when a vehicle starts, and the regenerative power generated by brake system increases the catenary voltage. To minimize the voltage fluctuation during the train operation and make use of the regenerative power, several types of energy storage systems are being studied. The energy storage system that is being recently introduced consists of the supercapacitors for energy storage and the bi-direction DC/DC converter for charge/discharge control. The efficiency of the energy storage system depends on the train operation pattern. In this paper, the operation efficiency of the energy storage system was quantitatively analyzed via simulation study taking consideration of the train operation patterns. The simulation was conducted changing the headway of trains with the energy storage system that uses the bi-direction DC/DC converter and supercapacitor. The simulation results showed that the operation efficiency of the energy storage system increases as the headway increase.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.5
• /
• pp.432-437
• /
• 2001

This paper describes a new developed 3.3KV/4MW class three-level Voltage Source Inverter(VSI), which is equipped with IIMS(Inverter Information Management System) based on the world wide web and with the Virtual operation simulator. The algorithm for motor control is the stator oriented Direct Torque Control(DTC), which works without speed sensor and gives the physically fastest dynamic response. The IIMS have the functions of operation monitoring and data managements. Virtual operation simulator can analyze and tune the system characteristics without main power. Now, this system is under the field test to verify the confidence.

• Journal of Power Electronics
• /
• v.15 no.3
• /
• pp.849-859
• /
• 2015

This paper proposes a novel compound-type hybrid energy storage system (HESS) that inherits the unique advantages of both battery/supercapacitor (SC) and the SC/battery HESSs for electric vehicles (EVs). Eight operation modes are designed to match this system. A mode control strategy is developed for this HESS on the basis of these modes, and five classes of operation modes are established to simplify this strategy. The mode control strategy focuses on high operating efficiency and high power output. Furthermore, the compound-type HESS is designed such that the SC is the main priority in braking energy absorption. Thus, this HESS can operate efficiently and extend battery life. Simulation results also show that the compound-type HESS can not only supply adequate power to the motor inverter but can also determine suitable operation modes in corresponding conditions. Experimental results demonstrate that this HESS can extend battery life as well. The overall efficiency of the compound-type HESS is higher than those of the battery/SC and the SC/battery HESSs.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.5 no.5
• /
• pp.467-474
• /
• 2000

This paper describes the development of 7he utility vehicle controller using combination system of battery and photovoltaic power for increasing operation time. In order to keep interchangeability, low cost and high performance, a separately excited DC Motor is controlled without velocity and current measurements by $\mu$-processor. For the parallel operation between the solar cell and battery, dc-dc converter is used, which is applied to the maximum power Point tracking(MPPT) and current control algorithm. By the simulation and experimental results of trial product, the vapidity of the proposed system is verified.

• Journal of Wind Energy
• /
• v.2 no.1
• /
• pp.90-96
• /
• 2011

The purpose of this paper is to describe the control system for optimal performance of 2MW gearless PMSG wind turbine system, and to afford some techniques of the algorithm selection and design optimization of the wind turbine control system through analysis of load calculation and control characteristic. Wind turbine control system is composed of the main control system and remote control and monitoring system. The main control system is industrial PC based controller, and the remote control and monitoring system is a server based computer system. The main control system has a supervisory control of the wind turbine with operation procedures and power-speed control through the torque control by pitch angle. There are some applications to optimize the wind turbine system at the starting mode with increasing of rotor speed, and cut-in operating mode to prevent trundling cut-in and cut-out, a gain scheduling of pitch PID controller, torque scheduling and limitation of generation power by temperature limitation or remote command by remote control and monitoring system. Also, the server operation program of the remote control and monitoring system and the design of graphical display are described in this paper.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.5
• /
• pp.334-341
• /
• 2021

Operation modes and control strategies for single-phase mobility charging station utilizing photovoltaic (PV) generation and energy storage systems (ESS) are proposed. This approach generates electric power from PV to transmit the mobility, ESS, and then transfer it to the grid when surplus electric power is generated during daytime. However, the PV power cannot be generated during night-time, and ESS and the mobility system can be charged using grid power. The power balance control based on power fluctuations and the resonant current control that can compensate harmonic components have been added to increase the stability of the system. The MATLAB/Simulink simulation was carried out to verify the proposed control method, and the 2-kW single-phase grid-tied PV-ESS smart mobility charger was built and tested.