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Dive into the research topics where Katsuhiko Uemura is active.

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Featured researches published by Katsuhiko Uemura.


IEEE Transactions on Power Apparatus and Systems | 1978

Modal Analysis for Power System Dynamic Stability

Shigenori Okubo; Hiroshi Suzuki; Katsuhiko Uemura

This paper deals with a numerical method to find the significant eigenvalues (damping factors and natural frequencies) and eigenvectors (oscillation mode shapes) in the dynamic stability range of a power system.


IFAC Proceedings Volumes | 1972

State Estimation of Large Scale Electric Power Systems by Decomposition Methods

Katsuhiko Uemura

Abstract This paper deals with the computational methods for the state estimation problem of a large-Scale electric Power system. This state estimation problem can be defined as the power flow problem which has overdetermined boundary conditions, and non-linear function minimization techniques can be used to solve the problem. The mathematical foundation of proposed methods is based upon the perturbed Newton method which includes as special cases standerd function minimization techniques such as Newton-Gauss method, Fretcher-Powel1 method and steerest descent method. The proposed methods in this paper are considered as decomposition methods for the reason that the coefficient matrices of iteration schemes are decomposed into block diagonal forms from the view joints of a power system configuration or a sersitivity between variab1es. These methods are suitable for the state-estimation problem which has many state variables for the simplicity of the coefficient moatrix in non-linear function minimization techniques.


IFAC Proceedings Volumes | 1985

Knowledge-Based Operation Guidance Method for Voltage and Reactive Power Control in Power Systems

A. Doi; Katsuhiko Uemura

Abstract This paper presents a new method for operation guidance of the voltage and Veactive power control in electric power systems. This control idea makes use of knowledge about the system state, control devices, operating rules, operator s experience and other requirements for an actual system operation. With this guidance method, the operator can easily obtain a desirable operating procedure which otherwise he would find after many trial-and-errors. As this method is based on a knowledge engineering technique, a suitable operating guidance tool for each utility can be easily built by rewriting the knowledge base.


Proceedings of the Eighth Power Systems Computation Conference#R##N#Helsinki, 19–24 August 1984 | 1984

A NEW EFFICIENT METHOD FOR INTEGRATED CONTROL OF VOLTAGE AND REACTIVE POWER IN POWER SYSTEMS

A. Doi; Shoichi Takeda; Katsuhiko Uemura

This paper presents an efficient method for the integrated control of voltage and reactive power in power systems. This method is able to maintain the bus voltages in their permissible limits while simultaneously realizing well-balanced operation of VAR sources and a reduction in active transmission losses. The proposed method has the following features compared with the conventional methods. (1) Voltage and reactive power control is divided into two parts: control of the switchable VAR sources and control of the load tap-changing transformers. This decomposition technique can realize well-balanced operation of VAR sources.


IFAC Proceedings Volumes | 1979

Operational Transfer Matrix Based Analysis of Power System Dynamic Stability

Hiroshi Suzuki; Katsuhiko Uemura

Abstract Eigenvalue method based on state space matrix and other conventional methods used for dynamic stability analysis are not suited for a multi-machine system consisting of hundreds of machines with automatic voltage regulators and speed governors. This paper shows that the frequency response method is very useful for such a large scale system. The stabillity analysis is based on operational transfer matrix from internal angles to input mechanical torques. The critical stability condition obtained by the proposed method is compared with that obtained from field tests and it is shown that the proposed method is sufficiently accurate and efficient. Eigenvalues and mode shapes of the power system are also calculated by using the operational transfer matrix. Two algorithms are presented; topological method and iteration method. The analysis methods are used for planning, design and operation of power systems.


Electrical Engineering in Japan | 1972

Approximation of an energy function in transient stability analysis of power systems

Katsuhiko Uemura; J. Matsuki; I. Yamada; T. Tsuji


Electrical Engineering in Japan | 1975

A new efficient method for calculating load flow of AC/DC systems

R. Miki; Katsuhiko Uemura


Electrical Engineering in Japan | 1977

Voltage stability condition of power systems and the effect of load characteristics

Shoichi Takeda; Katsuhiko Uemura


The transactions of the Institute of Electrical Engineers of Japan.B | 1978

On the Steady State Stability of Power Connection System in Consideration of Load Condition

Shigenori Okubo; Syoichi Takeda; Katsuhiko Uemura


Electrical Engineering in Japan | 1978

Steady-state stability of interconnected power system taking into account the loading condition

Shigenori Ohkubo; Syoichi Takeda; Katsuhiko Uemura

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A. Doi

Mitsubishi Electric

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