理工学部、建築・環境学部教養学会主催ミニ講演会
第５０回理科系学生のための公開英語講演会
English Lecture Meetings for Science-Major Students
Methods for Diagnosing High Voltage Equipment
高電圧機器の診断手法
講師：財団法人電力中央研究所名誉研究アドバイザー
本学工学総合研究所研究員
岡本 達希
On July 3rd, 2023, the 60th session of the English Lecture Meeting for Science Major Students was held under the sponsorship of the Academic Society of Faculty of Liberal Arts, inviting Doctor Tatsuki Okamoto to give a lecture with the above title, which was the 4th lecture for this event given by the lecturer.
Since present-day society is built on the use of electricity as a major source of energy, its transmission is an extremely important task for our lives. This means, at the same time, that any accident in its operation could cause disastrous consequences for our life. Therefore, it is an element of vital importance for our society to keep watching the transmission of electric power for its orderly function.
However, most of us, taking it for granted that we can always enjoy the benefit of electricity, do not know how the transmission of electric power is controlled; how it is watched and maintained 24-7; where those people are stationed, if any, who watch the transmission of electricity; and what kind of problem can occur in the process of transmission.
Dr. Okamoto, who has been engaged in the duty of maintaining the transmission of electric power for more than 40 years, was kind enough to give answers to those questions in this lecture based on his actual experiences concerning the transmission system. The lecturer also referred to various difficulties at the job sites.
Dr. Okamoto, a Research Adviser of Emeritus of Central Research Institute of Electric Power Industry （財団法人電力中央研究所名誉研究アドヴァイザー）, is an expert in the field of High Voltage Engineering, who has been engaged in the research of Diagnosis of High Voltage Electric Appliances and Development of Computer-Aided Diagnosis Technology.
In this lecture, Dr. Okamoto introduced the latest technology for diagnosing the conditions of large power appliances in electrical substations. The lecturer explained in detail that while various methods have been developed for diagnosing the conditions of the equipment in substations, the applicability of those methods to each piece of the equipment is by no means easy to determine since each part of the equipment has its own idiosyncratic property.
In concluding this lecture, Dr. Okamoto emphasized that development of diagnosis methods with ever higher reliability has always been called for, and that the quests for such ideal methods will always be an important task for those engaged in the transmission of electricity.
In the subsequent Q and A session, there were raised by the audience nine questions, to all of which the lecturer gave detailed answers, as exemplified by the following two questions and answers:
Q. Is there a way to detect the occurrences of water trees and electrical trees? Specifically, what kind of method, if any, is adopted for detecting their occurrences?
水ツリーや電気ツリーの発生を検知する方法はありますか？あるとするならば特にどのような方法が取られていますか。
A. It is difficult to answer your question briefly because there is no single ideal method for detecting neither the water tree nor the electrical tree; in fact, there are many methods for detecting them as shown by this table and usually several methods are combined for their detection depending on the situation of the accident.
Nonetheless, we could regard “the loss current method” for detecting the water tree and “the discharge detection method” for detecting the electric tree as the current mainstream methods for finding the signals of degradation. In each method, censors are put on the cables or transmission lines to measure the electric current, thereby spotting the signals of their degradation.
Thank you for asking a very good question.
Q. I understand that maintaining the flow of electric currents by means of transformers is an important function of substations, and that the operators of substations need to have technical skills to keep their regular functions. My question is “Aside from such regular tasks as repairing wirings, what other tasks are the operators in substations required to perform?”
変電所は変圧器で電流を維持していることを理解しました。この仕事をするのに技術が必要だと知りました。技術者は配線を直す他にどんな仕事をしていますか？
A. The main duty of the staff of substations is to keep the substations functioning normally; specifically, they need to monitor the conditions of transformers, switches, or monitoring systems. Besides, the maintenance of the buildings in substations, watching the conditions of the surrounding areas, keeping the communication with other substations and maintaining the securities of the substation are also important duties of power company members.
