Ryuichi Ishino

Measurement of frequency response of overhead power lines to wind

We have developed a new method which can the measure movement of overhead power lines in the wind. This method uses images from an ITV camera system. The sway of the power line is videotaped and analyzed. Its measured frequency response to wind is compared to a theoretical model and the measurement data obtained from an accelerometer. It is found that the new method yield results which are in good agreement with those obtained form the theoretical model for frequency response less than 0.5 Hz. A tension sensor and an accelerometer have been used to verify the theoretical model results. The accelerometer is used to obtain the eigenfrequency of sway. However, its results are not precise for less than 0.5 Hz. Using both the accelerometer and the new method, a method for measuring the frequency response of overhead power lines to wind, which was not previously possible, is now available.

New detection method of faulty distribution power apparatus using thermal images

In automatic diagnosis of a power distribution apparatus is utilizing thermal images problems arise in that there are problems, that there are many thermal patterns similar to the thermal pattern of the target apparatus and that the temperature around the apparatus influences the diagnosis. In order to solve these problems, we developed a new method whereby images of the apparatus are extracted by an image processing technique based on high-order local autocorrelation features, the attachment pattern on a pole, and a disparity map; a faulty apparatus is identified based on the local temperature gradient. In the extraction method, the distance information provided by the disparity map narrows the search area of the apparatus. The search is conducted according to the rule that an apparatus feature that is defined by high-order local autocorrelation features appears at certain intervals, according to the attachment pattern on a pole, in the search area. The local temperature gradient detects local heat in the form of leakage current on the faulty apparatus. Experiments using the proposed method were conducted under different weather conditions, at different times and seasons. An error rate of 3% was obtained from experiments on the extraction of an apparatus, and an error rate of 17% was obtained from experiments on the detection of a faulty apparatus. The proposed method can extract and detect faulty apparatuses, such as a pin insulator, a section switch and a strain insulator, except in the case where the distance between the pole and the infrared camera is so large that the sensitivity is insufficient.