The Kansai Electric Power Company (KEPCO), in cooperation with Hitachi, Ltd. and Fuji Electric Co., Ltd., has developed the largest power system simulator in the world. This will be used to solve problems in actual systems. The simulator has the following features:It is a large-scale system with a total of approximately 500 units, including 3 0 generators, 304 transmission lines, and 20 Loads, HVDC transmission facilities and static var compensators. It uses unique models. The generator model can simulate many types, including synchronous machine, induction machine, and adjustable speed pumpedstorage machine. The load model can simulate voltage characteristics with load dynamics. It uses a high-performance man-machine interface. This lets the operator input network configuration data through a system diagram image from the workstation, and control system data through a block diagram. It uses an automatic network configuration system which automatically sets an optimum unit and an save the connection work.This simulator was completed in April 1989, and then its test operation has been started for one year. It will then start to be used for practical applications.
The digital simulation method has been utilized to analyze phenomena in power systems. Since different algorithms can be applied, depending on the phenomena to be analyzed, digital simulation allows for high‐precision analysis. However, it also has a disadvantage: it produces continuous phenomena which occur in actual systems only fragmentarily. Thus, when discussing important projects at research centers such as IREQ in Canada, an analog simulator issued to continuously analyze the phenomena from the moment the fault occurs until steady state. These analog simulators, however, consist of only a few generator models. They are only effective for analyzing phenomena in small‐scale systems and do not allow for analysis of phenomena in large‐scale systems over a long period of time. For this reason, the Kansai Electric Power Company (KEPCO) in cooperation with Hitachi, Ltd., and Fuji Electric Co., Ltd., has developed the world's largest power system simulator (APSA: Advanced Power System Analyzer). The simulator will be used to analyze the evolution of accidents in actual systems and to analyze continuous system phenomena over a long period. This paper describes an outline of the simulator.
This paper addresses the subject of stationary and non-stationary voltage disturbance problems in electric power system. The modified binary-tree wavelet decomposition technique with an appropriate wavelet filter is introduced as a powerful tool for detecting, classifying, and quantifying the voltage disturbances. Power quality (PQ) indices in terms of total rms, rms of individual frequency bands, duration of disturbance, and their dependent quantities such as voltage magnitude of disturbance and harmonic distortion can be measured directly from the wavelet transform coefficients. The proposed technique is simple, provides accurate value of PQ indices, and enables to discriminate among the type of similar voltage disturbance events. The proposed technique is validated by its application to various disturbance data and the measurement results, such as rms and harmonic distortion, are further compared with those obtained from the time domain and frequency domain methods. Keywords:Power Quality, Binary-Tree Wavelet Transforms, Voltage Disturbances, Harmonics. (6)(7), and some include the classification purposes (2)(4) (10), but none is intended to include the quantification purposes. Moreover, CWT techniques are criticized due to their computational redundancy and they are often difficult to be implemented in realtime system. DWT techniques are not suitable for harmonic analysis, because the resulted frequency bands do not have the same width and the results do not give easy insight in the time behavior of the harmonics(9). In addition, the choice of which wavelet to use in PQ monitoring system also plays an important role(11), because the wavelet affects the accuracy of PQ indices, such as rms, harmonic distortion, and voltage magnitude of disturbances. A technique to detect, classify, and quantify voltage disturbances is proposed. The technique is based on binary-tree wavelet transform which has been modified to fit the monitoring requirements, and an appropriate wavelet filter has been chosen to yield good quantification. As compared with the recent PQ monitoring system as illustrated in reference [2] and in reference [10] which used respectively the DWT and the CWT, the proposed technique (1) enables harmonic analysis, (2) provides more easy measurement and accurate value of PQ indices, and (3) can be used mainly for both stationary and non-stationary disturbances, besides the ability to discriminate among the type of similar disturbance events.This paper starts with a brief introduction to binarytree wavelet theory and it is followed by the rms measurement in wavelet domain. The calculation of magnitude of disturbance and harmonic distortion indices is also presented. The proposed technique is evaluated to several voltage disturbance data with stationary (harmonics and flat-top) and non-stationary (sag, swell, and
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