• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.407-410
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• 2010

This paper presents an advanced load allocation algorithm in Direct Load Control(DLC) system. It is important to aggregate a various demand side resource which is surely controllable at the peak power time for a successful DLC system. Previous load allocation algorithm appropriate for DLC system is based on interchanged information, but, this algorithm can not derive optimal solutions. In this paper, we develop the optimal algorithm and the new load allocation algorithm in polynomial time. The simulation results show that the proposed heuristic algorithm for DLC system is very effective.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.264-265
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• 2006

This paper presents direct load control algorithm based locational and electric load characteristics. Direct load control is defined that demand-side management program activities that can interrupt consumer load at the time of annual peak load by direct control of the utility system operator by interruption power supply to individual appliances or equipment on consumer premises. Korean power system is divided into 14-areas considering branches operating in KEPCO, and electric loads are classified into 19 load groups considering interruption costs in this paper. The purpose of proposed method is to decrease social losses by controlling electric loads mainly whose interruption costs are low. It is expected that the proposed algorithm can be used as the countermeasure for the emergency state of the electric power dispatch in a operation point of view.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.8
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• pp.466-471
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• 2004

Electricity industries throughout the world are undergoing unprecedented changes. As a result, these changes lead to the separation of traditional integrated utilities and the introduction of competition in order that increase efficiency in electricity industry. Direct load control (DLC) system in competitive electricity market has a hierarchical interactive operation system, therefore, its control logic is also applied by bilateral interactive method that interchanges information related to interruptible load between operation hierarchies. Consequently, load curtailment allocation algorithm appropriate for new DLC system is required, and based on interchanged information, this algorithm should be implemented by most efficient way for each operation hierarchy. In this paper, we develop the load curtailment allocation algorithm in an emergency for new DLC system. Especially, the optimal algorithm for load aggregator (LA) that participates in competitive electricity market as a main operator for load management is developed.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.444-446
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• 2003

This paper deals with an allocation strategy for the resources of direct load control program, which is considered the operating states in power systems. The existing approaches, load shedding priority algorithm, curtailment payback based algorithm and mixed curtailment algorithm, are based on the uniform allocation strategy. These approaches are not taken into account the operating states in power systems. So, under the critical operating condition, direct load control resource is evaluated by introducing the congestion factor.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.371-377
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• 2005

Congestion problems of transmission lines are very important research issues in power system operations. Load curtailment is one of the ways to solve congestion problems by a major contingency. A systematic and effective mechanism for load shedding has been developed by investigating congestion distribution factors and the direct load control program. In this paper, a load shedding algorithm using linear programming for congestion problems by a major contingency is presented. In order to show the effectiveness of the proposed algorithm, it has been tested on the 6-bus sample system and the power system of Korea, and their results are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.78-83
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• 2004

Currently used DLC(Direct Load Control) algorithm is only focused on ON/OFF load control not concerning about reliving participated customer's inconvenience and load priority. Therefore, that is a major obstacle to attract customer participating in demand response program. To overcome the above defects, the authors represent direct load control algorithm using priority based dynamic programming. the proposed algorithm is that participant customer send E-mail to DLC center about priority of load before executing DLC, then DLC algorithm decide which load to be OFF by using priority and off time constraint of the load. By using dynamic programming based on the order of priority for DLC algorithm it is possible to maximize participating customer's satisfaction and it will help to attract more customer's participating in demand response program.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.633-635
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• 2003

Electricity industries throughout the world are undergoing unprecedented changes. As a result, these changes lead to the separation of traditional integrated utilities and the introduction of competition in order that increase efficiency in electricity industry. Direct load control (DLC) system in competitive electricity market has a hierarchical interactive operation system, therefore, its control logic is also applied by bilateral interactive method that interchanges information related to interruptible load between operation hierarchies. Consequently, load curtailment allocation algorithm appropriate for new DLC system is required, and based on interchanged information, this algorithm should be implemented by most efficient way for each operation hierarchy. In this paper, we develop the load curtailment allocation algorithm in an emergency for new DLC system. Especially, the optimal algorithm for load aggregator (LA) that participates in competitive electricity market as a main operator for load management is developed.

• Journal of Wind Energy
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• v.2 no.2
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• pp.54-60
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• 2011

A PMSG in variable speed wind turbine needs to know the position of rotor for vector control. Since the position sensor has the disadvantage in terms of cost, complexity of the system, a sensorless algorithm is needed. The sensorless strategy using the back EMF estimation is used for PMSG Wind Turbine. This algorithm is comparatively easy to implement than other strategies. This paper introduces the application of stable sensorless control for 2MW direct drive PMSG. In order to confirm the sensorless algorithm, the implementation is proceeded using 2MW direct drive PMSG from no-load condition to full-load condition. To drive 2MW PMSG artificially, 2MW PMSG connected PMSG through the mechanical coupling.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.107-115
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• 2006

The existing DLC system functionally has two defects. One is it has to be controlled by operators whenever customer's portion of loads are increased more than predefined objected load. Therefore, it may be possible for propagating uncontrolled loads if operators make a mistake. The other one is that currently used DLC algorithm is usually focused on ON/OFF load control not concerning about reliving participated customer's inconvenience. Therefore, that is a major obstacle to attract customer participating in demand response program. This paper represents direct load control system using active database. By using active database, DLC system can control customer's load effectively without intervening of operator. And by using dynamic programming based on the order of priority for DLC algorithm, it is possible to maximize participating customer's satisfaction.