• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.3-5
• /
• 1994

It is shown that the power flow considering the voltage characteristic of the composite load has some difference comparing with conventional load flow in this paper. When the load flow is used in a study of the static voltage stability, it is necessary to consider the voltage characteristic of load, since the composite load of a typical power system bas constant power, constant current, and constant impedance characteristic. The load is modeled to a polynomial form in here, and used in solving the load flow problem. In this way, the effect which the voltage characteristic of the load has on several voltage collapse proximity indicator based on sensitivities is compared with the conventional load flow, or with another load model having a different voltage characteristic. In this paper, the voltage collapse proximity indicator using the sensitivity of real power for transmission loss is also proposed, and compared with other indicators.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2738-2740
• /
• 2005

From composition transmitter is detached in indicator to individual load direction of 4 channels and adding up display by load cell indicator indication method of Bluetooth way is identifying marks.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.3
• /
• pp.224-228
• /
• 2005

In this paper, we investigate the main components of stray load loss of induction motors for ammonia compressors. The variations of the losses at each part of the motor due to load are calculated by the combined 3-D-2D finite element method formulated by the mixed moving coordinate systems. The stray load loss is calculated from these results due the definition of IEEE standard-112. It is clarified that the core loss and the eddy current loss of the can increase due to load, which can be considered as the main part of the stray load loss.

• Proceedings of the KIEE Conference
• /
• 2001.11c
• /
• pp.61-64
• /
• 2001

The electric power load during the peak time in summer is strongly affected by cooling load. which decreases the preparation ratio of electricity and brings about the failure in the supply of electricity in the electric power system. The ice-storage system and heat pump system etc are used to settle this problem. In this study, the method of estimating temperature and humidity to forecast the cooling load of ice-storage system is suggested. And also the method of forecasting the cooling load using neural network is suggested. For the simulation, the cooling load is calculated using actual temperature and humidity. The forecast of the temperature, humidity and cooling load are simulated. As a result of the simulation, the forecasted data approached to the actual data.

• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.89-91
• /
• 2001

This paper presents the result of pattern classification of load demand for distribution transformer in domestic. The field data of load demand is measured using the load acquisition device and the measurement data is used for the database system for load management of distribution transformed. For the pattern classification, the load data and the customer information data are also used. The K-MEAN method is used for the pattern classification algorithm. The result of pattern classification is used for the 2-step format of load demand curve.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.2
• /
• pp.315-323
• /
• 2015

Nowadays, it is expected that mobility loads such as electric railways and electric vehicles will be penetrated gradually and affect on the power system stability by their load characteristics. Various researches have been carried out about electric vehicles for the recent decade though the load of electric railway could be forecasted because of the specified path and timetable, is a field with a long historic background. Some precise 5th polynomial equations are required to analyze the power system stability considering mobility load to be increased in the immediate future while the electric railway dispatching simulator uses load models with constant power and constant impedance for the system analysis. In this paper, seasonal urban railway load models are established as the form of 5th polynomial equations and substation load modeling methods are proposed merging railway station load models and general load models. Additionally, load management effects by the load modeling are confirmed through the case studies, in which seasonal load models are developed for Seoul Subway Line No. 2, Gyeongui Line and Airport Railroad and the substation load change is analyzed according to the railway load change.

• KIEE International Transactions on Power Engineering
• /
• v.5A no.3
• /
• pp.252-259
• /
• 2005

Various problems such as increase of power loss and voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and restructuring of electric power companies makes the comprehensive management of reactive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of generation cost is derived and it is used for effectively determining the locations of reactive power compensation devices and for enhancing the load power factor appropriately. In addition, voltage variation penalty cost is introduced and integrated costs including voltage variation penalty cost are used for determining the value of load power factor from the point of view of economic investment and voltage regulation. It is shown through application to a large-scale power system that the load power factor can be enhanced effectively using the load power factor sensitivity and the integrated cost.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.1
• /
• pp.104-110
• /
• 2013

In this paper an application of centralized pitch angle controller for fixed speed wind turbines based wind farm to mitigate load frequency fluctuation is presented. Reference signal for the pitch angle of each wind turbine is calculated by using proposed centralized control system based on wind speed information. The wind farm in the model system is connected to a multi machine power system which is composed of 4 synchronous generators and a load. Simulation analyses have been carried out to investigate the performance of the controller using real wind speed data. It is concluded that the load frequency of the system can be controlled smoothly.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.850-853
• /
• 1998

This paper proposes a new short-term load forecasting method for special day, such as Public holidays, consecutive holidays, and days before and after holidays. when the load curves are quite different from those of normal weekdays. In this paper, two Artificial Neural Network(ANN) systems are applied to short-term load forecasting for spacial days in anomalous load conditions.

• KIEE International Transactions on Power Engineering
• /
• v.4A no.4
• /
• pp.254-261
• /
• 2004

Traditionally, electrical power systems had formed the vertically integrated industry structures based on the economics of scale. However, power systems have been recently reformed to increase their energy efficiency. According to these trends, the Korean power industry underwent partial reorganization and competition in the generation market was initiated in 2001. In competitive electric markets, accurate load data is one of the most important issues to maintaining flexibility in the electric markets as well as reliability in the power systems. In practice, the measuring load data can be uncertain because of mechanical trouble, communication jamming, and other issues. To obtain reliable load data, an efficient evaluation technique to adjust the missing load data is required. This paper analyzes the load pattern of historical real data and then the tuned ARIMA (Autoregressive Integrated Moving Average), PCHIP (Piecewise Cubic Interpolation) and Branch & Bound method are applied to seek the missing parameters. The proposed method is tested under a variety of conditions and also tested against historical measured data from the Korea Energy Management Corporation (KEMCO).