JP6519810B2 - Method and apparatus for diagnosing internal abnormality and deterioration of transformer - Google Patents

Method and apparatus for diagnosing internal abnormality and deterioration of transformer Download PDF

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JP6519810B2
JP6519810B2 JP2016174051A JP2016174051A JP6519810B2 JP 6519810 B2 JP6519810 B2 JP 6519810B2 JP 2016174051 A JP2016174051 A JP 2016174051A JP 2016174051 A JP2016174051 A JP 2016174051A JP 6519810 B2 JP6519810 B2 JP 6519810B2
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iron core
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小西 義則
義則 小西
雅道 加藤
雅道 加藤
松本 聡
松本  聡
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Shibaura Institute of Technology
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本発明は変圧器内部異常および劣化を、稼働中の変圧器を停止することなく容易に診断することができる方法と装置に関する。   The present invention relates to a method and an apparatus capable of easily diagnosing transformer internal abnormality and deterioration without shutting down an operating transformer.

変圧器は電力設備の重要な機器である。その使用寿命は数10年と長いので、使用期間中に変圧器が不具合なく稼働しているか否か、異常診断を行い、故障する前に適切な修理を施し得ることが重要である。また、使用中の機器を今後どの程度使い続けることができるのか劣化診断して更新計画を立てるなどの施策をとることが、機器の信頼性確保の面で重要であり、それら診断技術の高度化が望まれている。   Transformers are an important component of power equipment. Since its service life is as long as several tens of years, it is important to be able to diagnose whether or not the transformer is operating without any problems during the service period, and to perform appropriate repair before failure. In addition, it is important from the aspect of securing the reliability of the equipment that it is important to take measures such as degradation diagnosis and update planning to what extent the equipment in use can continue to be used in the future. Is desired.

機械の発する振動の大きさを測定して機械の調子を判断することは一般的によくなされている機械の設備診断の手段であり、機械の振動を解析する手段として「実験モード解析」が知られている(非特許文献1参照)。
実験モード解析においては、被試験体をハンマーで叩いて衝撃を加えたり、加振器と呼ばれる装置を用いたりして単一振動数で定常的に加振できる台の上に載せる方法か、接触させて加振する方法が採用されている。前者の方法で被試験体は固有振動数で振動し、減衰する様子を試験することができ、後者の方法では任意に周波数を変えて振動実験(周波数掃引加振実験)を行うと、印加した加振力と応答(周波数応答関数)の関連データが得られ、そのデータの中に隠れた形で混ざり合っている固有振動数、固有モード、減衰比の大きさ等を分析することができる。
It is a commonly used means of machine equipment diagnosis to measure the strength of the machine by measuring the magnitude of the machine's vibration, and "experimental modal analysis" is known as a means to analyze the machine's vibration. (See Non-Patent Document 1).
In the experimental modal analysis, whether the object to be tested is struck with a hammer and shocked or a device called a vibrator is used to place it on a table that can be constantly oscillated at a single frequency, or contact The method of causing it to vibrate is adopted. In the former method, it is possible to test that the test object vibrates and damps at the natural frequency, and in the latter method, it is applied when the frequency is arbitrarily changed and the vibration experiment (frequency sweep excitation experiment) is performed. Related data of excitation force and response (frequency response function) can be obtained, and natural frequencies, eigenmodes, magnitudes of damping ratios, etc. mixed in a hidden manner in the data can be analyzed.

また、機械の構造をモデル化し、力の釣り合いやエネルギー原理によって運動方程式を立て、それを解いて固有振動数と固有モードを求めることを「理論モード解析」と呼ぶ。しかし、理論モード解析において、自由度の大きい系では運動方程式を解析的に解くことが難しく、有限要素法を用いて解析されることがしばしばある。   Also, modeling the structure of a machine, establishing an equation of motion by force balance and energy principle, and solving it to determine natural frequency and natural mode is called "theoretical mode analysis". However, in theoretical mode analysis, it is difficult to solve the equation of motion analytically in a system with a large degree of freedom, and is often analyzed using a finite element method.

機械装置のものづくりにおいては、要求される機能が備わるように装置を設計することが第一である。しかし、新しい装置を稼働させると予想外の振動や騒音を発生する可能性があり、予想外の振動や騒音は装置使用者を不快にさせる可能性がある。そこで、ビジネスにおいては振動騒音特性を良くすることが競合他社との製品の差別化を図ることになるので、変圧器においては、設計段階から振動や騒音を発生させない工夫をするか、試作品の振動騒音特性を測定し、振動や騒音を低減する努力がなされている。
変圧器についても環境保全の社会的な要請や他社との差別化のために、各変圧器メーカーや各鉄鋼メーカーは低騒音化の対策を導入している。例えば、非特許文献2〜5に示すように、鉄心、巻線、タンク等の固有振動数を実験、理論の両面から解析し、機械の固有振動数が電源周波数の2倍に近くなり共鳴することを避ける工夫や、鉄心接合部形状の工夫などにより低騒音化する研究がなされている。
In the manufacture of mechanical devices, it is first to design the device to have the required functionality. However, the operation of the new device may generate unexpected vibration and noise, and the unexpected vibration and noise may make the device user uncomfortable. Therefore, in the business, improving vibration and noise characteristics will differentiate products from competitors, so in transformers, it is better to use a device that does not generate vibration or noise from the design stage, or Efforts have been made to measure vibration and noise characteristics to reduce vibration and noise.
As for transformers, each transformer manufacturer and each steel manufacturer have introduced measures to reduce noise in order to socially differentiate environmental protection and to differentiate them from other companies. For example, as shown in Non-Patent Documents 2 to 5, the natural frequencies of iron cores, windings, tanks, etc. are experimentally and analyzed from both sides of theory, and the natural frequency of the machine is close to twice the power supply frequency and resonates There are researches to reduce the noise by devising to avoid the problem and devising the shape of the core joint.

変圧器の設計や製造段階では実際に変圧器内部の構造物をハンマーで叩いたり、加振器で振動させたりすることが可能だが、稼働中の変圧器にそのような加振試験は適用できない。そこで、変圧器に流す電流が変圧器内部で鉄心や巻線に電磁力を作用し、鉄心や巻線から発生する振動や音から、変圧器内部を診断する方法が提案されている。
特許文献1では変圧器をハンマーで叩く代わりに、変圧器に励磁突入電流(定格電流の数倍)を流し、それにより発生する電磁機械力を用いて衝撃力を与え、発生音に基づいた診断を提案している。
また、加振器を用いる代わりに、所定の周波数範囲で励磁周波数を段階的に変化させて鉄心と巻線を加振して変圧器の固有振動数測定方法が特許文献2に記載されている。この場合、各加振周波数に対する変圧器騒音レベルを測定し、周波数応答関数を得ている。
Although it is possible to actually hammer the structure inside the transformer with a hammer or vibrate it with a vibrator at the design and manufacturing stages of the transformer, such a vibration test can not be applied to a transformer in operation . Therefore, there has been proposed a method of diagnosing the inside of the transformer from the vibration or sound generated from the iron core or the winding, in which the current supplied to the transformer exerts an electromagnetic force on the iron core or the winding inside the transformer.
In Patent Document 1, instead of striking a transformer with a hammer, an excitation inrush current (a multiple of the rated current) is applied to the transformer, an impact force is applied using the electromagnetic mechanical force generated thereby, and a diagnosis based on the generated sound Is proposed.
In addition, Patent Document 2 describes a method of measuring the natural frequency of a transformer by exciting an iron core and a winding by changing an excitation frequency stepwise in a predetermined frequency range instead of using an exciter. . In this case, the transformer noise level for each excitation frequency is measured to obtain a frequency response function.

特許第5691298号公報Patent No. 5691298 gazette 特開2008−82778号公報JP 2008-82778 A 特許第2550066号公報Patent No. 2550066 特開2010−271073号公報Unexamined-Japanese-Patent No. 2010-271073 特開平4−318905号公報Unexamined-Japanese-Patent No. 4-318905

長松昭男編著「音・振動のモード解析と制御」コロナ社刊行、(1996年)Akio Nagamatsu, ed., “Mode analysis and control of sound and vibration”, published by Corona, (1996) 前島正明、叶井実「最近の変圧器低騒音化技術」日立評論、vol.67 No.2 (1985)Maejima Masaaki, Sakurai Minoru "Recent Transformer Noise Reduction Technology" Hitachi Review, vol. 67 No. 2 (1985) 平石清登、堀康郎、志田茂「大容量変圧器巻線の短絡強度」日立評論、vol.51 No.6 (1969)Kiyoto Hiraishi, Yasuo Hori, Shigeru Shida "Short circuit strength of large capacity transformer winding" Hitachi Review, vol. 51 No. 6 (1969) 片柳厚志「変圧器タンクの振動解析」高岳レビュー、vol.56 No.1 (2011)Atsushi Katayanagi "Analysis of Transformer Tank Vibration" Takatake Review, vol. 56 No. 1 (2011) 溝上雅人、黒崎洋介「変圧器鉄心の接合部形式による騒音と磁歪の変化」電学論、vol.134 No.5 (2014)Mizokami Masato, Kurosaki Yosuke "Changes in noise and magnetostriction due to the junction type of transformer iron core" Electrology, vol. 134 No. 5 (2014) 電気学会技術報告、第1336号「電気的・音響的手法による変圧器の異常診断技術の最新動向」(2015)The Institute of Electrical Engineers of Japan Technical Report No. 1336, "Latest trends in transformer abnormality diagnosis technology using electrical and acoustic methods" (2015) 田中基八郎・堀康郎監修「電磁振動と騒音設計法」科学情報出版株式会社(2015)Tanaka Motohachiro and Hori Yasuro ed. Ed. "Electromagnetic Vibration and Noise Design Method" Science Information Publishing Co., Ltd. (2015) 華表宏隆、高野哲美、占部昇、渡辺賢治「モールド変圧器の光学式エポキシ樹脂劣化診断技術」電学論A,Vol.132 No.11(2012)Hirotaka Hanaomote, Tetsumi Takano, Noboru Otobe, Kenji Watanabe "Optical epoxy resin degradation diagnosis technology for molded transformers" Electrology A, Vol. 132 No. 11 (2012)

従来技術において、変圧器に励磁突入電流や励磁周波数を段階的に変化させた電流を流すのは、変圧器に複数の固有振動モードを発生させ、それらの固有振動数(以下、機械系の固有振動数と呼称する)を求めて変圧器を診断するために、複数の周波数成分をもつ加振力を変圧器内の鉄心や巻線に与えるためである。しかし、そのような特別な電流を流す試験は稼働中の変圧器に対しては適用できないため、稼働中の変圧器を試験のために停止しなくてはならない問題があった。   In the prior art, passing a current with a stepwise change in the excitation inrush current and the excitation frequency in the transformer causes the transformer to generate a plurality of natural vibration modes, and their natural frequencies (hereinafter referred to as mechanical system characteristics) In order to diagnose the transformer in order to determine the frequency), an excitation force having a plurality of frequency components is applied to the iron core or the winding in the transformer. However, there is a problem that the operating transformer has to be shut down for testing because such a special current test can not be applied to the operating transformer.

従って、本発明の課題は、稼働状態で変圧器の振動応答を解析して変圧器を診断する方法と診断する装置の提供にある。   SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus and method for analyzing a transformer's vibrational response under operating conditions to diagnose the transformer.

本発明の変圧器内部異常および劣化の診断方法は、鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器であって、稼働状態の変圧器振動について、低周波数領域から可聴音領域(1Hz〜20kHz) に検出感度を有する振動検出器を用い、電子回路またはソフトウエアを用いた信号処理に よる手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置において前記振動検出器から求めた出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークと、前記振動検出器により前記所定の負荷率で稼働中の変圧器のタンク表面の前記節の位置から外れた位置で測定した出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークとを比較し、測定位置を前記節の位置から変えることにより前記ピークが示す振動強度が変化した周波数の振動は前記タンクの振動と把握し、残りの振動を鉄心振動あるいは巻線振動と把握するとともに、前記残りの鉄心振動あるいは巻線振動について、前記振動検出器の測定位置を前記タンク表面の振動の節の位置に設定し、負荷率を前記所定の負荷率から変更して求めた前記フーリエ変換結果のピーク比較から、振動強度が変化しない周波数の振動を鉄心振動と判断し、振動強度が弱くなった周波数の振動を巻線振動と判断し、前記鉄心振動と巻線振動の一方または両方を健全な変圧器に対して前記方法と同等方法で求めた鉄心振動と巻線振動の一方または両方と比較して変化がある場合に内部異常および劣化を生じたと判断することを特徴とする。
本発明において、先に求めた鉄心振動と巻線振動の一方または両方が経時的に変化することを捕捉して稼働中の変圧器の状態を解析することができる。
The method for diagnosing internal abnormalities and deterioration of a transformer according to the present invention is a transformer having an iron core, a coil body, windings constituting the coil body, and a tank containing the coils, and the transformer vibration in the operating state, Using a vibration detector having detection sensitivity in the low frequency range to the audible sound range (1 Hz to 20 kHz), and using a means by signal processing using an electronic circuit or software, a predetermined load factor for the operating transformer can be obtained. in the vibration detector of a Fourier transform output waveform obtained at the position of the nodal smallest area of the tank surface vibration of the transformer in operation due to the electromagnetic force generated by the electric current which is added as a node of vibration to the results longitudinal axis vibration intensity, the peak of the horizontal axis results depicted in the graph is set to the frequency, the transformer tank surface running at a predetermined load factor by the vibration detector Comparing the peak results depicted in the graph that set the result ordinate vibration intensity and the horizontal axis the frequency output waveforms measured at a position deviated from the position of the node by Fourier transform, the measuring position of the node By changing from the position, the vibration of the frequency at which the vibration intensity indicated by the peak changes is grasped as the vibration of the tank, and the remaining vibration is grasped as iron core vibration or winding vibration, and the remaining iron core vibration or winding vibration The vibration intensity changes from the peak comparison of the Fourier transform results obtained by setting the measurement position of the vibration detector to the position of the node of vibration of the tank surface and changing the load factor from the predetermined load factor. Vibration of non-existent frequency is judged as iron core vibration, vibration of frequency whose vibration intensity is weakened is judged as winding vibration, and either or both of iron core vibration and winding vibration are paired with a sound transformer. It is characterized in that when there is a change as compared with one or both of the iron core vibration and the winding vibration obtained by the method equivalent to the above method, it is judged that the internal abnormality and the deterioration have occurred .
In the present invention, it is possible to analyze changes in time of one or both of the iron core vibration and the winding vibration determined previously and analyze the state of the operating transformer.

本発明は、鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器であって、稼働状態の変圧器振動について、振動検出器を用い、電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置における前記振動検出器の出力波形を測定し、この出力波形から変圧器電源周波数の整数倍波を抽出し、該整数倍波の振幅を規格化した波形と、前記変圧器の電源電流波形から前記整数倍波と同等周波数の振幅を規格化した波形を比較して両波形の位相差を求め、健全な変圧器で測定しておいた位相差と変化がある場合に内部異常および劣化を生じたと判断することを特徴とする。
本発明において、前記位相差が経時的に変化することを捕捉して稼働中の変圧器の状態を解析することができる。
The present invention is a transformer having an iron core, a coil body, a winding constituting the coil body, and a tank accommodating the coils, and an electronic circuit or software using a vibration detector for operating transformer vibration. The smallest area of tank surface vibration of the operating transformer due to the electromagnetic force generated by the energizing current applied to the operating transformer at a predetermined load factor by means of signal processing using hardware Measuring the output waveform of the vibration detector at the position of the node with the node of the vibration, extracting an integer multiple of the transformer power supply frequency from the output waveform, and standardizing the amplitude of the integer multiple, The phase difference between the two waveforms is determined by comparing the normalized waveform of the amplitude of the same integer multiple wave and the same frequency from the power supply current waveform of the transformer, and the phase difference and variation measured with a sound transformer are present. Internal error and Characterized by determining that resulted in deterioration.
In the present invention, it is possible to analyze that the phase difference changes with time and analyze the state of the operating transformer.

本発明は、鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器に対し適用される変圧器の内部異常および劣化の診断装置であって、稼働中の変圧器に装着されて該変圧器が発生する低周波数領域から可聴音領域(1Hz 〜20kHz)に至る振動に対し検出感度を有する振動検出器と、該振動検出器からの検 出信号を受けて稼働中の変圧器に対する通電電流による加振力に伴う機械的振動を求める解析器と、前記解析器から得られたデータを演算する演算手段とを備え、前記演算手段が、電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置において前記振動検出器から求めた出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークと、前記所定の負荷率で稼働中の変圧器のタンク表面の振動の節の位置から外れた位置で測定した出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークとを比較し、測定位置を前記節の位置それより外れた位置に変えることにより前記ピークが示す振動強度が変化した周波数の振動は前記タンクの振動と把握し、残りの振動を鉄心振動あるいは巻線振動と把握し、前記残りの鉄心振動あるいは巻線振動について、前記振動検出器の測定位置を前記タンク表面の振動の節の位置に設定し、負荷率を前記所定の負荷率から変更して求めた前記フーリエ変換結果のピーク比較から、振動強度が変化しない振動を鉄心振動と判断し、振動強度が弱くなった振動を巻線振動と判断するとともに、前記鉄心振動と巻線振動の一方または両方について、健全な変圧器に対して前記同等方法で求めた鉄心振動と巻線振動の一方または両方と比較して変化がある場合に内部異常および劣化を生じたと前記演算手段が判断する機能を有したことを特徴とする。 The present invention is a device for diagnosing internal abnormalities and deterioration of a transformer applied to a transformer having an iron core, a coil body, a winding constituting the coil body, and a tank accommodating the coils, which is in operation. A vibration detector mounted on a transformer and having detection sensitivity to vibration ranging from a low frequency region generated by the transformer to an audible sound region (1 Hz to 20 kHz), and a detection signal from the vibration detector. The analyzer comprises: an analyzer for obtaining mechanical vibration associated with an excitation force due to current flowing to the operating transformer; and calculation means for calculating data obtained from the analyzer, the calculation means comprising an electronic circuit or software the smallest area of the transformer operating status due to the electromagnetic force generated by energizing current being added at a predetermined load ratio in operation transformer tank surface vibration using means by signal processing using Longitudinal axis vibration intensity results output waveform obtained from the vibration detector at the position of the nodal as a node of vibration by Fourier transform, the peak of the results depicted in the graph set on the horizontal axis the frequency, the predetermined load Fourier transform the output waveform measured at a position away from the position of the node of the vibration of the tank surface of the transformer in operation, and draw the result on the graph set to the vertical axis vibration intensity and horizontal axis frequency By comparing the peak with the peak and changing the measurement position to the position of the node and the position away from it , the vibration of the frequency at which the vibration intensity indicated by the peak changes is grasped as the vibration of the tank, and the remaining vibration is iron core vibration Alternatively, it is grasped as winding vibration, and regarding the remaining iron core vibration or winding vibration, the measurement position of the vibration detector is set to the position of the node of vibration of the tank surface, and the load factor is determined from the predetermined load factor. From the peak comparison of the Fourier transform results obtained by changing, it is determined that the vibration in which the vibration intensity does not change is an iron core vibration, the vibration in which the vibration intensity is weakened is determined as a winding vibration, and the iron core vibration and the winding vibration The computing means determines that an internal abnormality and deterioration have occurred when there is a change in one or both of the sound transformer and the iron core vibration and the winding vibration obtained by the equivalent method with respect to the sound transformer. It is characterized by having the following function .

本発明は、鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器に対し適用される変圧器の内部異常および劣化の診断装置であって、稼働中の変圧器に装着される振動検出器と、該振動検出器からの検出信号を受けて稼働中の変圧器に対する通電電流による加振力に伴う機械的振動を求める解析器と、前記解析器から得られたデータを演算する演算手段とを備え、稼働状態の変圧器振動について、前記振動検出器を用い、電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置における前記振動検出器の出力波形を測定し、この出力波形から変圧器電源周波数の整数倍波を抽出し、該整数倍波の振幅を規格化した波形と、前記変圧器の電源電流波形から前記整数倍波と同等周波数の振幅を規格化した波形を比較して両波形の位相差を求め、健全な変圧器で測定しておいた位相差と変化がある場合に内部異常および劣化を生じたと判断する機能を前記演算手段が有することを特徴とする。 The present invention is a device for diagnosing internal abnormalities and deterioration of a transformer applied to a transformer having an iron core, a coil body, a winding constituting the coil body, and a tank accommodating the coils, which is in operation. A vibration detector attached to the transformer, an analyzer for obtaining mechanical vibration accompanying an excitation force by the supplied current to the operating transformer in response to a detection signal from the vibration detector; Calculation means for calculating the stored data, and for the transformer vibration in the operating state, using the vibration detector, using the means by signal processing using an electronic circuit or software to specify the transformer in the operating state; Measuring the output waveform of the vibration detector at the position of the node with the smallest area of the tank surface vibration of the operating transformer due to the electromagnetic force generated by the applied current at a load factor of The integer harmonics of the transformer power supply frequency are extracted from the output waveform, and the amplitude of the integer harmonics is standardized from the power supply current waveform of the transformer and the waveform in which the amplitude of the integer harmonics is normalized. The calculation means has a function of determining the phase difference between the two waveforms by comparing the obtained waveforms, and determining that internal abnormality and deterioration have occurred when there is a change in phase difference measured with a sound transformer. It features.

本発明の診断方法によれば、稼働中の変圧器を停止せずとも稼働状態のまま内部異常および劣化を外部診断できるようになる。
また、電気的振動における周波数応答解析では、鉄心やコイルが実際にずれを生じたあとで異常が診断されるが、本発明に係る診断方法では、コイル巻線の締付け力低下を診断することができるので、実際にずれが生じる前に異常を把握できる方法であり、変圧器の予防保全の方法としても優れた診断方法である。
According to the diagnostic method of the present invention, it is possible to externally diagnose internal abnormalities and deterioration in the operating state without stopping the operating transformer.
Moreover, in the frequency response analysis in electrical vibration, although an abnormality is diagnosed after an iron core and a coil actually produce a shift, in the diagnostic method according to the present invention, a decrease in tightening force of a coil winding can be diagnosed. Since it can be done, it is a method that can grasp abnormalities before the deviation actually occurs, and it is an excellent diagnostic method as a method of preventive maintenance of transformers.

本発明に係る変圧器の異常および劣化を診断する装置の第1実施形態を示す構成図。BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows 1st Embodiment of the apparatus which diagnoses abnormality and deterioration of the transformer which concerns on this invention. 本発明で測定対象とする変圧器の一例構成を示すもので、(A)は一部を破断とした斜視略図、(B)はコイル部分の拡大断面図。An example structure of the transformer made into the measurement object by this invention is shown, (A) is the perspective schematic view which made one part fracture, (B) is an expanded sectional view of a coil part. 変圧器巻線の振動を近似して運動方程式を立てる際に参考とする1自由度力学モデルの構成図。The block diagram of a one-degree-of-freedom dynamic model used as a reference when making an equation of motion by approximating the vibration of a transformer winding. 稼働中の変圧器タンクの壁面中央付近から測定されたレーザー変位計による振動検出波形の一例を示すグラフ。The graph which shows an example of the vibration detection waveform by the laser displacement meter measured from wall surface center vicinity of the working transformer tank. 図4に示す波形をフーリエ変換して得た波形の一例を示すグラフ。The graph which shows an example of the waveform obtained by Fourier-transforming the waveform shown in FIG. 図4に示す波形から電源周波数の2倍波(100Hzの成分)を抽出した結果の波形を示すグラフ。The graph which shows the waveform of the result of extracting the 2nd harmonic (component of 100 Hz) of a power supply frequency from the waveform shown in FIG. 変圧器の電源電流波形を2乗して100Hz成分を規格化した波形と図6に示す波形との位相差を示すグラフ。The graph which shows the phase difference of the waveform which squared the power supply current waveform of a transformer, and normalized the 100 Hz component, and the waveform shown in FIG. 高周波成分を用いて粘度項の係数を求める方法の一例を示す図。The figure which shows an example of the method of calculating | requiring the coefficient of a viscosity term using a high frequency component. 負荷率60%で稼働中の変圧器においてタンクの壁面中央で測定されたAEセンサの出力波形をフーリエ変換した波形の一例を示すグラフ。The graph which shows an example of the waveform which Fourier-transformed the output waveform of AE sensor measured in the wall surface center of a tank in the transformer in operation with 60% of a load factor. 図9に示す波形について縦軸を対数目盛にして表示したグラフ。The graph which displayed the vertical axis | shaft on the logarithmic scale about the waveform shown in FIG. 図9に示す波形を求める際にタンク中央から65cm下方位置において測定されたAEセンサの出力波形をフーリエ変換した波形の一例を示すグラフ。The graph which shows an example of the waveform which Fourier-transformed the output waveform of AE sensor measured in the 65-cm lower position from a tank center, when calculating | requiring the waveform shown in FIG. 負荷率30%で稼働中の変圧器においてタンクの壁面中央で測定されたAEセンサの出力波形をフーリエ変換した波形の一例を示すグラフ。The graph which shows an example of the waveform which Fourier-transformed the output waveform of AE sensor measured in the wall surface center of a tank in a transformer in operation with 30% of a load factor. 補償法による測定の一例を説明する図。The figure explaining an example of the measurement by a compensation method. 実施例において試験に適用した変圧器タンクの概要を示す斜視図。The perspective view which shows the outline | summary of the transformer tank applied to the test in the Example. 図14に示す変圧器タンクに収容されている鉄心の振動モードを示すもので、(A)はねじりモードを示す斜視図、(B)は曲げモード1を示す斜視図、(C)は曲げモード2を示す斜視図。FIG. 14 shows the vibration mode of the iron core housed in the transformer tank shown in FIG. 14, (A) is a perspective view showing a twisting mode, (B) is a perspective view showing a bending mode 1 and (C) is a bending mode FIG. 実施例において変圧器タンクの上部右側壁にセンサを取り付けた位置を示す説明図。Explanatory drawing which shows the position which attached the sensor to the upper right side wall of the transformer tank in the Example. 実施例において得られた変圧器タンクの実稼働時と加振時の振動測定結果をフーリエ変換した値を示すグラフ。The graph which shows the value which Fourier-transformed the vibration measurement result at the time of real operation of the transformer tank obtained in the Example, and excitation.

<第1実施形態>
以下、本発明に係る変圧器の異常および劣化の診断方法と診断装置の第1実施形態について油入変圧器の場合を例にとり、図面に基づき説明する。
図1は変圧器の異常および劣化を診断する装置の第1実施形態を示す構成図であり、本実施形態の診断装置Aは、一例として図2に示す構造の油入変圧器1の異常および劣化を診断する装置である。
この例の油入変圧器1は、タンク2の内部に複数の巻線型のコイル体3がそれらの中心軸を上下に向けて収容され、タンク2の内部に絶縁油が満たされてなる。各コイル体3の中心部にケイ素鋼板などの磁性体からなる鉄心5が挿通され、各鉄心5は各々の上下端部においてケイ素鋼板などの磁性体からなるロッド状のヨーク部6に一体化されている。
各鉄心5の両端部とヨーク部6の周囲を囲むように枠状の締め金部7が設けられ、上下の締め金部7に図2(B)に示すように締め付け金具8が延出形成され、上下の締め付け金具8により各コイル体3が上下から挟まれ、各コイル体3に締め付け力が付加されている。
First Embodiment
Hereinafter, a first embodiment of a method and an apparatus for diagnosing abnormality and deterioration of a transformer according to the present invention will be described based on the drawings taking an oil-filled transformer as an example.
FIG. 1 is a block diagram showing a first embodiment of a device for diagnosing abnormality and deterioration of a transformer, and a diagnosis device A of this embodiment is an abnormality of oil-filled transformer 1 having a structure shown in FIG. 2 as an example. It is a device that diagnoses deterioration.
In the oil-filled transformer 1 of this example, a plurality of winding type coil bodies 3 are accommodated inside the tank 2 with their central axes up and down, and the inside of the tank 2 is filled with insulating oil. The iron cores 5 made of magnetic material such as silicon steel plate are inserted into the central part of each coil body 3, and each iron core 5 is integrated with the rod-like yoke 6 made of magnetic material such as silicon steel plate at each upper and lower end. ing.
Frame-like clamps 7 are provided so as to surround both ends of each iron core 5 and the periphery of the yoke 6, and the clamps 8 extend from the upper and lower clamps 7 as shown in FIG. 2 (B). The coil bodies 3 are sandwiched from above and below by the upper and lower clamps 8, and a clamping force is applied to each coil body 3.

本実施形態においてコイル体3は、図2(B)に示すように外側コイル9と内側コイル10からなり、外側コイル(1次コイル)9は外巻線(1次巻線)11と絶縁スペーサー(固体絶縁物)12を上下に積層した積層体を上部絶縁体13と下部絶縁体15により挟み付けて構成されている。内側コイル(2次コイル)10は内巻線(2次巻線)16と絶縁スペーサー(固体絶縁物)17を上下に積層した積層体を上部絶縁物18と下部絶縁物19で挟み付けて構成されている。
上部絶縁物13、18と下部絶縁物15、19を上下の締め付け金具8により挟み付けることで各コイル体3には上下から締め付け力が作用され、この状態でコイル体3は絶縁油に浸漬されている。
また、タンク2の天井またはタンク側面に電力を入出力するための図示略のブッシングが形成されている。
In the present embodiment, as shown in FIG. 2B, the coil body 3 is composed of an outer coil 9 and an inner coil 10, and the outer coil (primary coil) 9 is an outer winding (primary winding) 11 and an insulating spacer A stacked body in which (solid insulators) 12 are stacked up and down is sandwiched between an upper insulator 13 and a lower insulator 15. The inner coil (secondary coil) 10 is configured by sandwiching a stacked body in which an inner winding (secondary winding) 16 and an insulating spacer (solid insulator) 17 are stacked up and down with an upper insulator 18 and a lower insulator 19. It is done.
By clamping the upper insulators 13 and 18 and the lower insulators 15 and 19 with the upper and lower clamps 8, a clamping force is applied to each coil body 3 from the upper and lower sides, and in this state, the coil body 3 is immersed in the insulating oil ing.
Further, a bushing (not shown) for inputting and outputting electric power is formed on the ceiling of the tank 2 or on the side of the tank.

前記構成の変圧器1は、送電線などから送られる高電圧を電力使用者の近くで降圧する用途などに使用されるので、巻線11、16には常時電流が流されている。巻線11、16に電流を流すことで電磁力が作用するので、コイル体3や鉄心5には電磁力が作用し、これらが振動する。この振動は変圧器1の全体に伝わり、タンク2の側壁2Aや底壁2B、天井壁2Cにも伝達される。
また、送電線で短絡事故や地絡事故などが起きると変圧器1の巻線11、16には定格負荷電流の10倍から数10倍に達する大きな電流が流れることがあり、規格以上の電磁力と振動が変圧器1に作用することもある。
これら種々の要因から、変圧器1の絶縁油は経時的に徐々に劣化が進行する。また、締め付け力と振動が常時作用する絶縁スペーサー12、17はセルロース繊維からなるため、劣化するおそれがあり、短絡事故や地絡事故に起因して巻線11、16にも予想外の劣化を生じるおそれがある。
以上説明のように変圧器1は長期間使用することにより各部において劣化が進行するおそれがある。
Since the transformer 1 of the said structure is used for the application etc. which pressure | voltage-falls the high voltage sent from a power transmission line etc. in the vicinity of a power user, current always flows through the winding 11 and 16. Since an electromagnetic force acts by supplying an electric current to the windings 11 and 16, the electromagnetic force acts on the coil body 3 and the iron core 5 to vibrate them. This vibration is transmitted to the whole of the transformer 1, and is also transmitted to the side wall 2A, the bottom wall 2B, and the ceiling wall 2C of the tank 2.
In addition, when a short circuit accident or a ground fault accident occurs in a transmission line, a large current that may reach 10 times to several tens times the rated load current may flow in the windings 11 and 16 of the transformer 1, Forces and vibrations may also act on the transformer 1.
Due to these various factors, the insulating oil of the transformer 1 gradually deteriorates with time. In addition, since the insulating spacers 12 and 17 on which clamping force and vibration always act are made of cellulose fiber, they may be deteriorated, and unexpected deterioration is also caused on the windings 11 and 16 due to a short circuit accident or a ground accident. It may occur.
As described above, the use of the transformer 1 for a long time may cause deterioration in each part.

図1に示す変圧器1の異常および劣化の診断装置Aは、変圧器1に沿わせて配置される振動検出器(振動センサ)22と、この振動検出器22からの出力信号を受けて増幅する増幅器(振動センサアンプ)25とこの増幅器25からの出力を受ける信号解析器(位相差検出器)26とこの信号解析器26に接続された演算装置27を主体として構成されている。診断装置Aにおいて、変圧器1に通電するための電圧を計測する電圧計(通電電圧計)23とこの電圧計23に増幅器(通電電圧アンプ)24を介し信号解析器26が接続されている。   The diagnostic device A for abnormality and deterioration of the transformer 1 shown in FIG. 1 receives and amplifies a vibration detector (vibration sensor) 22 disposed along the transformer 1 and an output signal from the vibration detector 22. An amplifier (vibration sensor amplifier) 25 and a signal analyzer (phase difference detector) 26 receiving an output from the amplifier 25 and an arithmetic unit 27 connected to the signal analyzer 26 are mainly configured. In the diagnostic device A, a voltmeter (energization voltmeter) 23 for measuring a voltage for energizing the transformer 1 and a signal analyzer 26 are connected to the voltmeter 23 via an amplifier (energization voltage amplifier) 24.

図1に示す診断装置Aを用いて以下に説明する手順で変圧器1の振動を解析するが、本実施形態の診断装置Aが異常および劣化の診断を行う場合に用いる実験モード解析に従う基本理論について以下に説明する。
まず、変圧器巻線の振動を1自由度系で減衰のある強制振動と近似して運動方程式を立てる。巻線の質量をm、こわさをk、粘性をc(減衰係数)で表現する。こわさkをばねで表示し、粘性cをダンパで表示すると図3に示すようになる。この自由度力学モデルは非特許文献1において解説されている。
時刻tにおける変位をx(t)と表し、大きさF、角振動数ωの調和加振力を作用させる場合の運動方程式は以下の(1)式で表すことができる。
Although the vibration of the transformer 1 is analyzed by the procedure described below using the diagnostic device A shown in FIG. 1, a basic theory according to the experimental mode analysis used when the diagnostic device A of the present embodiment diagnoses an abnormality and deterioration. Will be described below.
First, an equation of motion is made by approximating the vibration of a transformer winding as a damped forced vibration in a system of one degree of freedom. The mass of the winding is represented by m, the stiffness by k, and the viscosity by c (damping factor). The stiffness k is represented by a spring, and the viscosity c is represented by a damper as shown in FIG. This mechanical model with degrees of freedom is described in Non-Patent Document 1.
The displacement at time t is represented by x (t), and the equation of motion in the case of applying a harmonic excitation force of magnitude F and angular frequency ω can be represented by the following equation (1).

Figure 0006519810
Figure 0006519810

前記(1)式において変位xを以下の(2)式と仮定して解くと以下の(3)式、(4)式が得られる。   The following equations (3) and (4) can be obtained by solving the displacement x assuming the following equation (2) in the equation (1).

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

ここで、前記(3)、(4)式において、Ω=(k/m)1/2は不減衰固有角振動数を示し、β=ω/Ωは外力の角周波数と不減衰固有角振動数の比を示し、c=2(m/k)1/2は臨界減衰係数、ζ=c/cは減衰比(粘性減衰と臨界減衰係数の比)を示す。
前記(4)式は調和加振力から位相が遅れた角周波数ωの振動式として以下の(5)式〜(9)式に展開することができる。
Here, in the equations (3) and (4), Ω = (k / m) 1/2 represents the undamped natural angular frequency, and β = ω / Ω represents the angular frequency of the external force and the undamped natural angular vibration The ratio of numbers is shown, c c = 2 (m / k) 1/2 is the critical damping coefficient, and ζ = c / cc is the damping ratio (ratio of viscous damping to critical damping coefficient).
The equation (4) can be expanded into the following equations (5) to (9) as a vibration equation of the angular frequency ω whose phase is delayed from the harmonic excitation force.

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

前記(9)式において、位相差φは以下の(10)式で与えられる。   In the equation (9), the phase difference φ is given by the following equation (10).

Figure 0006519810
Figure 0006519810

よって、前記(2)式で仮定した変位Xは以下の(11)式で与えられる。   Therefore, the displacement X assumed by the equation (2) is given by the following equation (11).

Figure 0006519810
Figure 0006519810

前記(1)式は右辺が0ではないので、非斉次線形微分方程式である。非斉次線形微分方程式の一般解は、線形斉次方程式の一般解と非斉次方程式を満たす1つの特解の和で書くことができる。前記(4)式は非斉次方程式の(1)式を満たす1つの特解である。ここで線形斉次方程式は以下の(12)式で与えられる。   The equation (1) is an inhomogeneous linear differential equation because the right side is not zero. The general solution of an inhomogeneous linear differential equation can be written as the general solution of a linear homogeneous equation and the sum of one special solution that satisfies the inhomogeneous equation. The equation (4) is one special solution satisfying the equation (1) of the nonhomogeneous equation. Here, the linear homogeneous equation is given by the following equation (12).

Figure 0006519810
Figure 0006519810

前記(12)式の一般解を求めると、以下の(13)式が得られる。   If the general solution of the equation (12) is obtained, the following equation (13) is obtained.

Figure 0006519810
Figure 0006519810

前記(13)式において以下の(14)式の関係がある。   The following equation (14) holds in the equation (13).

Figure 0006519810
Figure 0006519810

前記(14)式には平方根があり、その中身の正負により異なる現象が出現する。
ζ≧1の場合、λ、λはともに負の実数になり、時間とともに大きさが減少して零に近付く無周期運動となる。よって、この場合、前記(1)式の一般解は、前記(11)式で与えられる調和加振力の角振動数ωの振動と前記(13)式で与えられる無周期運動の和で表される。
ζ<1の場合、σ=Ωζ:減衰率、ω=Ω(1−ζ1/2:減衰固有角振動数を導入すると、前記(13)式は以下の(15)式で表すことができる。
The above equation (14) has a square root, and different phenomena appear depending on whether the contents are positive or negative.
When ζ 1 1 , both λ 1 and λ 2 become negative real numbers, and the magnitude decreases with time, resulting in aperiodic motion approaching zero. Therefore, in this case, the general solution of the equation (1) is represented by the sum of the vibration of the angular frequency ω of the harmonic excitation force given by the equation (11) and the aperiodic motion given by the equation (13) Be done.
In the case of ζ <1, σ = Ωζ: Attenuation rate, ω D = Ω (1−ζ 2 ) 1/2 : When the damped natural angular frequency is introduced, the above equation (13) is expressed by the following equation (15) be able to.

Figure 0006519810
Figure 0006519810

よって、この場合、(1)式の一般解は、前記(11)式で与えられる調和加振力の角振動数ωと前記(15)式で与えられる減衰固有角振動数ωの2つの成分を持つ振動となる。
一方、N自由度系に外力{f}が作用するときの運動方程式は、以下の(16)式で表される。
Therefore, in this case, the general solution of the equation (1) includes two of the angular frequency ω of the harmonic excitation force given by the equation (11) and the damped natural angular frequency ω D given by the equation (15) It becomes a vibration with a component.
On the other hand, an equation of motion when an external force {f} acts on an N degree of freedom system is expressed by the following equation (16).

Figure 0006519810
Figure 0006519810

ただし、前記(16)式において[M]は質量行列、[C]は減衰行列、[K]は剛性行列を表し、それぞれN次元の正方行列である。
一般にN次元空間において、N個の互いに独立なベクトル群{φ}〜{φ}があれば、それらを基準とする座標系を形成し、それによって任意のN次元ベクトルを表現することができ、その表現式は以下の(17)式、(18)式で示される。
However, in said (16) Formula, [M] is a mass matrix, [C] is an attenuation matrix, [K] represents a stiffness matrix, and it is an N-dimensional square matrix, respectively.
Generally, in N-dimensional space, if there are N mutually independent vector groups {φ 1 } to {φ N }, form a coordinate system based on them, thereby representing an arbitrary N-dimensional vector The expression is given by the following equations (17) and (18).

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

N自由度系は、N次元空間を形成するとみなせば、互いに質量行列[M]、減衰行列[C]、剛性行列[K]に関して一般直交性を有するN次元ベクトル群であるから、固有モードを基準ベクトルとする座標系を形成することができる。
すると、N自由度系の運動方程式(16)式はr次固有モードに関する1自由度系の以下の運動方程式(19)式に帰着する。
Since an N-degrees-of-freedom system is considered to form an N-dimensional space, it is an N-dimensional vector group having general orthogonality with respect to mass matrix [M], attenuation matrix [C], and stiffness matrix [K]. A coordinate system can be formed to be a reference vector.
Then, the equation of motion (16) of the N degree of freedom system reduces to the following equation of motion (19) of the one degree of freedom system relating to the r th -order eigenmode.

Figure 0006519810
Figure 0006519810

前記(19)式において、m={ψ[M]{ψ}:モード質量、c={ψ[C]{ψ}:モード減衰係数、k={ψ[K]{ψ}:モード剛性である。
多自由度系内の自由度iだけに角振動数ω、振幅Fiの調和加振力が作用する場合には、外力ベクトル{f}は、i行目がFijωtで他の全項が零になる。これを前記(19)式に代入すると、以下の(20)式となる。
In the above equation (19), m r = {ψ r } T [M] {ψ r }: mode mass, cr = {ψ r } T [C] {ψ r }: mode damping coefficient, k r = { ψ r } T [K] {ψ r }: mode stiffness.
When the harmonic excitation force with angular frequency ω and amplitude Fi acts only on the degree of freedom i in the multi-degree-of-freedom system, the external force vector {f} has all other terms in the i- th row F i e jωt. Becomes zero. Substituting this into the equation (19) gives the following equation (20).

Figure 0006519810
Figure 0006519810

前記(20)式において、ψriはr次固有モード{ψ}のi行目の項である。
前記(20)式は1自由度系における前記(1)式と同一の形式である。
解ξを調和関数で表現すると仮定すれば、r次固有モードに関して解は以下の(21)式となる。
In the equation (20), ri ri is a term in the i-th row of the r th eigenmode {モ ー ドr }.
The equation (20) has the same form as the equation (1) in a single degree of freedom system.
Assuming that the solution ξ r is expressed as a harmonic function, the solution is the following equation (21) for the r th -order eigenmode.

Figure 0006519810
Figure 0006519810

これを前記(18)式に代入し、すべての固有モードに関して和をとると、空間座標上で解として以下の(22)式を得ることができる。   Substituting this into the equation (18) and summing the all eigenmodes, the following equation (22) can be obtained as a solution on spatial coordinates.

Figure 0006519810
Figure 0006519810

前記(16)式は右辺が0ではないので、非斉次線形微分方程式である。前記(16)式の一般解もまた線形斉次方程式の一般解と非斉次方程式を満たす1つの特解の和で記載できる。前記(22)式は非斉次方程式である(16)式を満たす1つの特解である。ここで、線形斉次方程式は以下の(23)式で与えられる。   The above equation (16) is an inhomogeneous linear differential equation because the right side is not zero. The general solution of the above equation (16) can also be described by the general solution of a linear homogeneous equation and the sum of one special solution satisfying an inhomogeneous equation. The equation (22) is one special solution that satisfies the equation (16), which is an inhomogeneous equation. Here, the linear homogeneous equation is given by the following equation (23).

Figure 0006519810
Figure 0006519810

この(23)式の一般解を求める。減衰行列[C]が以下の(24)式で表されるような比例粘性減衰である場合を例として以下のように考えることができる。   The general solution of this equation (23) is obtained. The following can be considered with an example where the damping matrix [C] is proportional viscosity damping as represented by the following equation (24).

Figure 0006519810
Figure 0006519810

ここで、変位を以下の(25)式と仮定する。   Here, the displacement is assumed to be the following equation (25).

Figure 0006519810
Figure 0006519810

すると、前記(23)式は以下の(26)式で示すことができる。   Then, the equation (23) can be expressed by the following equation (26).

Figure 0006519810
Figure 0006519810

ここで、前記(26)式に前記(24)式を代入し、以下の(27)式と置けば、前記(23)式は以下の(28)式となる。   Here, when the equation (24) is substituted into the equation (26) and the equation (27) below is set, the equation (23) becomes the following equation (28).

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

ここで、(28)式を解いて求めたpを(27)式に代入すると、r次のλrは以下の(29)式のように求まる。   Here, when p obtained by solving the equation (28) is substituted into the equation (27), the r-order λr can be obtained as the following equation (29).

Figure 0006519810
Figure 0006519810

ここで、固有角振動数は以下の(30)式で示され、モード減衰率は以下の(31)式で示され、減衰固有角振動数は以下の(32)式で示され、r次のモード減衰比は以下の(33)式で示される。   Here, the natural angular frequency is represented by the following equation (30), the mode damping factor is represented by the following equation (31), and the damped natural angular frequency is represented by the following equation (32). The modal damping ratio of is expressed by the following equation (33).

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

Figure 0006519810
Figure 0006519810

以上から、前記(16)式の一般解は前記(22)式で与えられる調和加振力の角振動数ωと減衰固有角振動数を示す前記(32)式に現れる減衰角固有角振動数ωrdの成分を持つ振動である。 From the above, the general solution of the equation (16) is the damped angular natural angular frequency which appears in the equation (32) which indicates the angular frequency ω of the harmonic excitation force and the damped natural angular frequency given by the equation (22) It is a vibration with a component of ω rd .

一方、稼働状態の変圧器が発生する振動・騒音の伝搬経路が、前述の非特許文献2に記載されている。
振動・騒音の一次的原因は鉄心の振動と巻線の振動であり、両者の振動がタンク、その他に伝搬する。よって、変圧器タンクの振動は鉄心振動と巻線振動とタンク自身の振動の合成となる。鉄心の状態を診断する場合は通電騒音振動のうち、鉄心振動成分を評価し、巻線の状態を診断する場合は巻線振動成分を評価する。鉄心振動と巻線振動はそれぞれ固有振動数を有する。
固有振動数が電源系の振動数に近いと共鳴現象が起きる。加振力は電源周波数の2倍成分が最も大きいが、電源周波数の奇数倍または偶数倍の加振力も存在し、鉄心振動や巻線振動やタンク振動の固有振動数が電源周波数の2倍以外の整数倍に近い場合には、電源周波数の2倍成分の振動よりも大きな振幅を生じる場合がある。電源系の加振力に対する機械系の固有振動数を測定して変圧器内部異常および劣化診断をすることができる。また、機械系の固有振動振幅が小さいなどの理由で固有振動数の直接の測定が困難である場合には強制振動の位相差を解析することにより、機械系の固有振動数を求め、請求項3に記載のように変圧器内部異常および劣化診断をすることができる。
即ち、変圧器構成物の固有振動数(鉄心振動と巻線振動とタンク自身の振動のそれぞれの固有振動数)を求めて稼働中の変圧器の状態を解析することができる。
On the other hand, the propagation path of the vibration and noise generated by the transformer in the operating state is described in the above-mentioned Non-Patent Document 2.
The primary causes of vibration and noise are core core vibration and winding vibration, and both vibrations are transmitted to the tank and others. Thus, the vibration of the transformer tank is a combination of iron core vibration, winding vibration and tank's own vibration. When diagnosing the state of the iron core, the core vibration component is evaluated among the energized noise and vibration, and when diagnosing the state of the winding, the winding vibration component is evaluated. The iron core vibration and the winding vibration each have a natural frequency.
When the natural frequency is close to the frequency of the power supply system, a resonance phenomenon occurs. The excitation power is the largest of the double power supply frequency, but there is also an odd or even multiple of the power supply frequency, and the natural frequency of iron core vibration, winding vibration and tank vibration is other than twice power frequency If the frequency is close to an integral multiple of, the amplitude may be larger than the vibration of the double component of the power supply frequency. The natural frequency of the mechanical system with respect to the excitation force of the power supply system can be measured to diagnose internal abnormality and deterioration of the transformer. In addition, when direct measurement of the natural frequency is difficult because the natural vibration amplitude of the mechanical system is small, etc., the natural frequency of the mechanical system is determined by analyzing the phase difference of the forced vibration, and claim As described in 3, the transformer internal abnormality and deterioration diagnosis can be performed.
That is, it is possible to analyze the state of the transformer in operation by obtaining the natural frequency of the transformer component (the natural frequency of each of the core vibration, the winding vibration and the vibration of the tank itself).

基本的に加振力は電源周波数の2倍成分である。しかし、電源電圧の歪み、発生する磁力の歪み、伝達される力の歪みなどが関与して色々な固有周波数をもつ振動が誘起されると考えられる。
変圧器1におけるタンク2の振動を鉄心振動と巻線振動とタンク振動の3成分ごとに分ける手順について説明する。3成分の振動は重ね合わせの原理が成り立つとする。
タンク壁面中央で振動測定する場合、縦方法または横方向の偶数の腹を持つタンク振動については振動の節となり、縦横両方向の奇数の腹を持つタンク振動成分のみとなる。よってタンク壁面中央で振動測定すると、振動波形は縦横両方向の奇数の腹を持つタンク振動成分と鉄心振動と巻線振動の重ね合わせとなる。次に、タンク中央よりやや下の位置で振動を測定すれば、タンク中央では消えていた縦方法または横方向の偶数の腹を持つタンク振動が測定され、縦横両方向の奇数の腹を持つタンク振動成分は振幅が小さくなる。
Basically, the excitation force is twice the power source frequency. However, it is considered that vibrations with various natural frequencies are induced due to distortion of power supply voltage, distortion of generated magnetic force, distortion of transmitted force and the like.
The procedure of dividing the vibration of the tank 2 in the transformer 1 into the three components of iron core vibration, winding vibration and tank vibration will be described. It is assumed that the three component vibration holds the principle of superposition.
When the vibration is measured at the center of the tank wall, the tank vibration having an even number of antinodes in the longitudinal direction or in the lateral direction is a node of vibration, and only the tank vibration component having an odd antinode in both longitudinal and lateral directions. Therefore, when vibration is measured at the center of the tank wall surface, the vibration waveform is a superposition of the tank vibration component having odd antinodes in both the vertical and horizontal directions and the iron core vibration and the winding vibration. Next, if the vibration is measured at a position slightly lower than the center of the tank, the tank vibration with an even number of longitudinal method or lateral direction which has disappeared in the center of the tank is measured. The component has smaller amplitude.

一方、鉄心振動と巻線振動の大きさは変わらない。このようにタンク表面の位置を変えて測定することにより、すべてのタンク振動について固有振動成分を把握でき、残るは鉄心振動と巻線振動の分離である。
負荷電流の有無により、鉄心中の磁束は変わらないので、鉄心振動は変わらないが、巻線の振動は電流のほぼ2乗に比例して変化することが非特許文献6の87ページに記載されている。よって、負荷電流を変えて振動を測定し、その負荷依存性を利用すると鉄心振動と巻線振動を分離してそれぞれの振動波形を測定可能となる。
On the other hand, the magnitudes of iron core vibration and winding vibration do not change. By measuring the position of the tank surface in this way, the natural vibration component can be grasped for all tank vibrations, and the remaining is the separation of the core vibration and the winding vibration.
Since the magnetic flux in the iron core does not change depending on the presence or absence of load current, iron core vibration does not change, but it is described on page 87 of Non-Patent Document 6 that winding vibration changes in proportion to the current squared. ing. Therefore, the load current is changed to measure the vibration, and by using the load dependency, it is possible to separate the iron core vibration and the winding vibration and to measure each vibration waveform.

「巻線振動の解析」
次に、巻線振動の解析例について説明する。
一般的な油入変圧器の寿命は、変圧器の外部で短絡故障が発生した場合に変圧器コイル巻線に加わる電磁機械力にコイルの絶縁紙が耐えられなくなった状態と考えられる。
一方、短絡故障時に巻線の軸方向にも一次巻線(外巻線)と二次巻線(内巻線)が反発する電磁力(外部推力)が作用する。巻線部に挿入された絶縁物が経年劣化により寸法収縮して、巻線の締付け力が低下した場合、外部推力により軸方向の巻線構造が損なわれる可能性が生じる。このような状態も変圧器の寿命と考えられる。締付け力が低下して巻線に緩みが生じると巻線からの騒音は大きくなる。
特許文献4の記載によると、変圧器の各部位の締付けトルク値が規定値よりも小さくなると、正常時の各周波数成分のレベルが分布する範囲から大きく外れたレベルになると説明されている。
"Analysis of winding vibration"
Next, an analysis example of winding vibration will be described.
The life of a general oil-filled transformer is considered to be a state in which the insulating paper of the coil can not withstand the electromagnetic mechanical force applied to the transformer coil winding when a short circuit failure occurs outside the transformer.
On the other hand, at the time of a short circuit failure, an electromagnetic force (external thrust) which the primary winding (outer winding) and the secondary winding (inner winding) repel also acts in the axial direction of the winding. If the insulator inserted in the winding portion shrinks due to age deterioration and the clamping force of the winding decreases, the external thrust may possibly damage the axial winding structure. Such a condition is considered to be the life of the transformer. If the tightening force is reduced and the winding becomes loose, the noise from the winding increases.
According to the description of Patent Document 4, when the tightening torque value of each portion of the transformer becomes smaller than the specified value, it is described that the level of each frequency component in normal time is a level largely deviated from the distribution range.

次に、変圧器の巻線に印加される加振力について説明する。
変圧器巻線の内巻線16と外巻線11には反対方向に電流が流れており、たがいに漏れ磁場を形成する。巻線に印加される電磁力はローレンツ力であり、電流と磁界にそれぞれ直角方向に作用する。軸方向の電磁力は内巻線16も外巻線11もともに圧縮力となり、電磁力は電流の2乗に比例する。よって、軸方向の加振力の振動数は電流の振動数(すなわち電源周波数)の2倍となる。
巻線11、16の締付け力の低下は巻線の固有振動数の変化として現れる。よって、実験モード解析により、直接的あるいは後述の補償法を用いて巻線振動に含まれる振動成分を明らかにすれば良い。直接的とは、AEセンサや加速度センサの生の波形をフーリエ変換して振動成分を明らかにすることを意味する。
Next, the excitation force applied to the transformer winding will be described.
Current flows in the opposite direction in the inner winding 16 and the outer winding 11 of the transformer winding, forming a leakage magnetic field. The electromagnetic force applied to the winding is the Lorentz force, which acts perpendicular to the current and the magnetic field, respectively. The electromagnetic force in the axial direction is a compressive force for both the inner winding 16 and the outer winding 11, and the electromagnetic force is proportional to the square of the current. Therefore, the frequency of the oscillating force in the axial direction is twice the frequency of the current (ie, the power supply frequency).
The decrease in the clamping force of the windings 11 and 16 appears as a change in the natural frequency of the windings. Therefore, it is only necessary to clarify the vibration component included in the winding vibration by using the compensation method described below or directly by experimental modal analysis. Direct means that the raw waveform of the AE sensor or the acceleration sensor is subjected to Fourier transform to reveal the vibration component.

次に、位相差φ(通電電流による加振力の位相を基準とする変圧器振動の位相の差)から電源の振動数に対して巻線の固有振動数を求めることができる。電源周波数の2倍もしくは共鳴の影響で大きな信号強度を有する振動モードがr番目のモードであるとする。r番目のモードに対する位相差をφrとすると、前記(10)式を用いて巻線のr番目の固有振動数Ωは以下の(34)式のように計算できる。その際、減衰係数cは別な実験より求めておく。 Next, the natural frequency of the winding can be determined with respect to the frequency of the power supply from the phase difference φ (the difference in the phase of the transformer vibration with respect to the phase of the excitation force due to the current flow). It is assumed that the vibration mode having a large signal strength due to the effect of twice the power supply frequency or resonance is the r-th mode. Assuming that the phase difference with respect to the r-th mode is φr, the r-th natural frequency Ω r of the winding can be calculated using the equation (10) as in the following equation (34). At that time, the attenuation coefficient cr is determined from another experiment.

Figure 0006519810
Figure 0006519810

変圧器の振動のうち振幅は小さいが自由振動を直接的に、あるいは、後述の補償法およびロックインアンプを用いる測定によって求めることができる。
減衰係数cを求める方法は加振力の振動数より数倍大きな固有振動数を持つモードiについて測定する方法である。減衰係数cの値はモードごとに異なると考えられるが、加振力の振動数においてもその値で近似することができる。
その場合、加振力が1周期経過する前に現れる数周期分の減衰運動から減衰係数cを求めることとする。図8はその波形の説明である。
一般に減衰自由振動波形の振幅は指数関数的に減衰する。そこで、隣り合う振幅の比の対数をとると常に一定の値になると考えられ、この隣り合う振幅の比の自然対数は対数減衰率δと呼ばれる。時刻tにおけるn番目の振幅をa、同様にn+1、…、n+m番目の振幅をan+l、…、an+mとすると、対数減衰率δは以下の(35)式で定義される。
Among the vibration of the transformer, the amplitude is small but free vibration can be determined directly or by measurement using a compensation method and a lock-in amplifier described later.
The method of determining the damping coefficient c is a method of measuring the mode i having a natural frequency several times larger than the frequency of the excitation force. The value of the damping coefficient c is considered to be different for each mode, but can be approximated by the value also in the frequency of the excitation force.
In that case, the damping coefficient c i is determined from the damping motion for several cycles that appear before one cycle of the excitation force elapses. FIG. 8 is an explanation of the waveform.
In general, the amplitude of the damped free oscillation waveform decays exponentially. Therefore, I thought to always be a constant value when taking the logarithm of the ratio of adjacent amplitudes, the natural logarithm of the ratio of the adjacent amplitude is called the logarithmic decrement of [delta] i. Assuming that the n-th amplitude at time t n is a n and the n + 1,..., N + m-th amplitudes are a n + 1 ,..., A n + m , the logarithmic attenuation factor δ i is defined by the following equation (35).

Figure 0006519810
Figure 0006519810

δはδと等しいと近似すると、r次のモード減衰比ζは以下の(36)式で求められる。 When approximating that δ r is equal to δ i , the r-order mode damping ratio ζ r can be obtained by the following equation (36).

Figure 0006519810
Figure 0006519810

これにより、減衰係数cは、以下の(37)式で求められる。 Thus, the damping coefficient c r is calculated by the following equation (37).

Figure 0006519810
Figure 0006519810

ところで、巻線の固有振動数と締付け力の関係は以下の(38)式で与えられる。   The relationship between the natural frequency of the winding and the clamping force is given by the following equation (38).

Figure 0006519810
Figure 0006519810

ここで、Lは巻線の軸方向の長さ、ρは巻線を分布定数系とみなした場合の線密度を表す。また、前記(34)式と(38)式より、締め付け力Tは以下の(39)式のように求めることができる。   Here, L represents the axial length of the winding, and ρ represents the linear density when the winding is regarded as a distributed constant system. Further, from the equations (34) and (38), the tightening force T can be determined as the following equation (39).

Figure 0006519810
Figure 0006519810

巻線の固有振動数は自由振動における前記(32)式の減衰固有角振動数を2πで割ってモード減衰比を用いて求めることもできる。
しかし、変圧器が比較的新品に近い場合、巻線締付け力は十分に大きく、振動が発生しにくくなっている。すなわち、減衰係数cが臨界減衰係数cよりも大きく、減衰比ζは1より大きいと考えられる。その場合、固有振動数に関係する振動は発生せず、無周期の減衰運動になる。その結果、強制振動が与えられても強制振動の振動数以外の振動成分は発生しなくなる。そのような場合でも、位相遅れを測定する方法であれば、固有振動数に関する情報が得られる。
The natural frequency of the winding can also be determined using the modal damping ratio by dividing the damping natural angular frequency of the equation (32) in free vibration by 2π.
However, when the transformer is relatively new, the winding tightening force is sufficiently large that vibration hardly occurs. That is, it is considered that the damping coefficient c is larger than the critical damping coefficient c c and the damping ratio ζ is larger than one. In that case, no vibration related to the natural frequency occurs, resulting in aperiodic damping motion. As a result, even if the forced vibration is applied, vibration components other than the frequency of the forced vibration do not occur. Even in such a case, if it is a method of measuring phase delay, information on natural frequency can be obtained.

前記(39)式で求められる締付け力Tが変圧器の設計下限値以上の場合は、当該変圧器の劣化度は健全であると診断され、設計下限値を下回ると外部推力による破壊確率が高まった状態であると判断し、当該変圧器の劣化度は寿命に達したと診断できる。
一例として、図1に示す解析器26と演算装置27はパーソナルコンピューターから構成され、演算装置27がCPUであり、メモリやハードディスクなどの記憶装置が解析器26に搭載され、解析器26の記憶装置に健全な初期状態の変圧器の締め付け力Tの情報が記憶されている。前記した各式が解析器26の記憶装置に記録されており、測定結果から得られる巻線の固有振動数などの情報が解析器26の記憶装置に記録され、健全な初期状態の変圧器の締め付け力との対比がなされる。
解析器26の記憶装置に健全な初期状態の変圧器の締め付け力とその締め付け力に対し、何割程度の低下が見られるかに応じて対比テーブルが記録されている。実際に測定され、演算装置27により計算された締め付け力の低下が、初期状態に対し低下していることが判明した場合に、当該変圧器の劣化度が寿命に達したか否か診断される。診断の基準値は変圧器ごとに個別に設定する。診断の基準値を解析器26の記憶装置に記録しておき、演算装置27の測定結果とテーブルを対比判断することにより変圧器の寿命を診断できる。
When the tightening force T determined by the equation (39) is equal to or more than the design lower limit value of the transformer, the deterioration degree of the transformer is diagnosed as healthy. It can be determined that the transformer has reached the end of its life.
As an example, the analyzer 26 and the arithmetic unit 27 shown in FIG. 1 are constituted by a personal computer, the arithmetic unit 27 is a CPU, and a storage device such as a memory or a hard disk is mounted on the analyzer 26. The information of the tightening force T of the transformer in a sound initial state is stored. Each equation described above is recorded in the storage device of the analyzer 26, and information such as the natural frequency of the winding obtained from the measurement result is recorded in the storage device of the analyzer 26, and the transformer in the sound initial state A comparison with the clamping force is made.
A comparison table is recorded in the storage device of the analyzer 26 according to what percentage of a drop is found with respect to the tightening force of the sound transformer in the initial state and the tightening force. If it is found that the decrease in the tightening force actually measured and calculated by the arithmetic device 27 is lower than the initial state, it is diagnosed whether or not the deterioration degree of the transformer has reached the end of life . The reference value for diagnosis is set individually for each transformer. It is possible to diagnose the life of the transformer by recording the reference value of the diagnosis in the storage device of the analyzer 26 and comparing and judging the measurement result of the arithmetic unit 27 and the table.

位相差から機械系の固有振動数を求める場合、巻線部に使用されている絶縁物の劣化が軽度の場合は電源周波数の2倍の振動(2倍振動)が主な変圧器振動であり、2倍振動の位相差に着目して解析するのが良い。
ただし、機械系の固有振動数が電源周波数の2倍の振動数とは別な整数倍の振動数に近い場合、共鳴の効果でより大きな振動振幅を与える場合があり、その場合はその大きな振幅の振動数成分について解析する方が良い場合もある。
When the natural frequency of a mechanical system is determined from the phase difference, if the deterioration of the insulator used in the winding part is mild, the vibration twice as high as the power supply frequency (the vibration twice) is the main transformer vibration. It is good to analyze paying attention to the phase difference of double vibration.
However, if the natural frequency of the mechanical system is close to a frequency that is an integral multiple of the frequency twice the frequency of the power supply frequency, the effect of resonance may give a larger vibration amplitude, in which case the large amplitude Sometimes it is better to analyze the frequency component of.

締付け力が低下すると、巻線の軸方向に作用する電磁力に加え、巻線の半径方向に作用する電磁力による振動も発生すると考えられ、変圧器の劣化が進行すると、高次の振動成分の振幅が大きくなると考えられる。そこで、劣化が進んだ変圧器については高次の振動成分の振幅に着目して解析することが有効である。   If the tightening force decreases, in addition to the electromagnetic force acting in the axial direction of the winding, it is considered that the vibration due to the electromagnetic force acting in the radial direction of the winding is also generated. It is believed that the amplitude of Therefore, it is effective to analyze by focusing on the amplitude of the high-order vibration component for the transformer that has deteriorated.

高次の固有振動モードによる過渡振動は前記(22)式で示される定常振動に加算される振動成分と考えられ、前記(25)式で与えられる。
本実施形態では変圧器の通電により発生するローレンツ力を加振力として用いるが、加振力はただ1つの振動数成分であり、すべての振動モードに対する効率の良い加振力になり得ていない可能性がある。しかし、劣化が進んだ変圧器で巻線締付け力が弱くなってくると、巻線に緩みが生じ、単振動の加振力が歪んで、伝達され、色々なモードの振動が誘起されると考えられる。
そこで、2倍振動振幅に対しより高次の振動成分の振幅が大きくなることを捉えて巻線部に使用されている絶縁物が劣化していると診断することができる。この場合、高次の振動成分は歪んで伝達された加振力により決まった位相遅れを有するようになると考えられる。
よって、位相が一定しない背景雑音は除去することにより、歪んで伝達された加振力により決まった位相遅れを生じている高次の振動成分を把握し、巻線部に使用されている絶縁物の劣化に関係した高次の振動成分の振幅の増大を捉えることができる。
ただし、変圧器製造段階の内部応力が経年で緩和され、高次の振動振幅が小さくなる場合も考えられ、その変化の要因を解釈して変圧器を診断せねばならない。よって、変圧器ごとに決まる特定の周波数成分が経時的に変化することを捕捉して稼働中の変圧器の状態を解析して診断する。診断の基準値は変圧器ごとに個別に設定する。
一例として、図1に示す解析器26が測定結果のグラフを解析して高次の固有振動の増大を認めたならば、変圧器1の劣化度が算定される。高次の固有振動の増大割合を予め解析器26の記憶装置に劣化度に応じて記録しておき、演算装置27が算出した増大割合に応じて当該変圧器の劣化度がどの程度であるのか、また、変圧器としての寿命に達したか否か診断される。
The transient vibration due to the high-order natural vibration mode is considered as a vibration component to be added to the steady-state vibration shown by the equation (22), and is given by the equation (25).
Although Lorentz force generated by energization of the transformer is used as excitation force in this embodiment, the excitation force is only one frequency component and can not be efficient excitation force for all vibration modes. there is a possibility. However, if the winding tightening force becomes weak in the degraded transformer, the winding loosens and the vibration force of the single vibration is distorted and transmitted, causing various modes of vibration to be induced. Conceivable.
Therefore, it can be diagnosed that the insulator used in the winding part is deteriorated by grasping that the amplitude of the higher order vibration component becomes larger with respect to the double vibration amplitude. In this case, higher order vibration components are considered to be distorted and to have a fixed phase delay due to the transmitted excitation force.
Therefore, by removing background noise whose phase is not constant, it is possible to grasp high-order vibration components that cause a phase delay determined by the distorted and transmitted excitation force, and to use the insulator used in the winding part An increase in the amplitude of higher order vibration components related to the degradation of
However, the internal stress at the transformer manufacturing stage may be relieved over time, and the high-order vibration amplitude may be reduced, and the cause of the change must be interpreted to diagnose the transformer. Therefore, the fact that the specific frequency component determined for each transformer changes over time is analyzed to analyze and diagnose the state of the operating transformer. The reference value for diagnosis is set individually for each transformer.
As an example, if the analyzer 26 shown in FIG. 1 analyzes the graph of the measurement result and recognizes an increase in the high-order natural vibration, the degree of deterioration of the transformer 1 is calculated. The rate of increase of the high-order natural vibration is recorded in advance in the storage device of the analyzer 26 according to the degree of deterioration, and to what extent is the degree of deterioration of the transformer concerned according to the rate of increase calculated by the arithmetic unit 27 Also, it is diagnosed whether or not the life as a transformer has been reached.

低次の2倍振動成分から高次の固有振動成分まで広く解析するには、広い周波数特性を有するAE(アコースティックエミッション)センサを用いることができる。または、低周波と高周波とそれぞれに感度の高いAEセンサを組み合わせて用いることもできる。または、特定の周波数ごとに感度の高いAEセンサを組み合わせて用いることもできる。
また、振動を測定するセンサであれば、AEセンサに限らず、加速度センサや、振動を音波で測定するか、変圧器タンク壁面の振動を直接レーザー変位計で測定するなどの方法により解析することも可能である。
An AE (Acoustic Emission) sensor having a wide frequency characteristic can be used to widely analyze from the low-order double vibration component to the high-order natural vibration component. Alternatively, it is possible to use a combination of low frequency and high frequency and high sensitivity AE sensors. Alternatively, high sensitivity AE sensors can be used in combination for each specific frequency.
In addition, if it is a sensor that measures vibration, it is not limited to an AE sensor, but it is not limited to an acceleration sensor or a method of measuring vibration with sound waves or analyzing vibration of the transformer tank wall directly with a laser displacement meter Is also possible.

「鉄心振動の解析」
次に、鉄心振動の解析例について説明する。
鉄心は電磁鋼板の磁歪により振動が生じる。磁歪は磁場の向きが変わるたび、すなわち通電電流1周期に対し2回振動を発生する。変圧器の鉄心はねじ止めされるか、バンドにて締付けられている。長年変圧器を使用していると繰返しの振動や温度変化により、ねじに緩みが生じて締付け力が低下する可能性がある。
電磁鋼板の磁歪により鉄心の継鉄(ヨーク)と脚鉄(コア)が揺さぶられ、振動するようになる(非特許文献6参照)。鉄心の締付け力が低下すると振動が発生し騒音は大きくなる。
鉄心の接合部ではわずかな空気の層が存在し、磁束が空気の部分を避けて鋼板を通るため、鋼板間に吸引力が働く。積層された鋼板は完全に平坦でなく、部分的な接触になっており、積層方向には全体として、ばねとして作用する。ばね定数は締付け力によって変化する。また締付け力が弱くなると、鋼板間のすべりが生じ、減衰係数が小さくなる。
よって、締付け力が変化するとばね定数や減衰係数の変化として固有振動数が変化する。固有振動数や減衰係数の変化を捉えて、鉄心の締付け力低下といった異常や劣化を診断することができる。
一例として、図1に示す解析器26が測定結果のグラフを解析して締め付け力の低下の程度を認めたならば、変圧器1の劣化度が算定される。締め付け力の低下割合を予め解析器26の記憶装置に低下割合に応じて記録しておき、低下した割合に応じて当該変圧器の劣化度がどの程度であるのか、また、変圧器としての寿命に達したか否か診断される。
診断の基準値は変圧器ごとに個別に設定する。
"Analysis of core vibration"
Next, an analysis example of core vibration will be described.
The iron core is vibrated by the magnetostriction of the magnetic steel sheet. The magnetostriction generates vibration twice each time the direction of the magnetic field changes, that is, for one cycle of the supplied current. The transformer core is screwed or tightened with a band. When a transformer has been used for many years, repeated vibration or temperature change may cause the screw to loosen and reduce the tightening force.
Due to the magnetostriction of the magnetic steel sheet, the yoke (leg) of the iron core and the leg iron (core) are shaken and vibrated (see Non-Patent Document 6). If the tightening force of the iron core decreases, vibration occurs and the noise increases.
At the joints of the core, there is a slight air layer, and the magnetic flux passes through the steel plate avoiding the air portion, so that a suction force is exerted between the steel plates. The laminated steel plates are not completely flat but in partial contact and act as a spring as a whole in the laminating direction. The spring constant changes with the tightening force. In addition, if the tightening force becomes weak, slippage between the steel plates occurs, and the damping coefficient decreases.
Therefore, when the tightening force changes, the natural frequency changes as the change of the spring constant or the damping coefficient. By detecting changes in the natural frequency and the damping coefficient, it is possible to diagnose abnormalities or deterioration such as a decrease in clamping force of the iron core.
As an example, if the analyzer 26 shown in FIG. 1 analyzes the graph of the measurement result and recognizes the degree of decrease in the tightening force, the degree of deterioration of the transformer 1 is calculated. The rate of decrease in tightening force is recorded in advance in the storage device of the analyzer 26 according to the rate of decrease, and the degree of deterioration of the transformer according to the rate of decrease is also the life as a transformer It is diagnosed whether it has reached.
The reference value for diagnosis is set individually for each transformer.

「乾式変圧器の場合の解析」
次に、乾式変圧器の振動解析による診断について説明する。
乾式変圧器はモールド変圧器とも呼ばれ、絶縁油の代わりに絶縁物のエポキシ樹脂で変圧器内を浸し、硬化させたものである。よって、乾式変圧器の主な劣化要因はエポキシ樹脂の熱劣化である(非特許文献8参照)。
エポキシ樹脂は熱劣化すると、機械的強度が低下して、短絡電流や地震などの外力によりクラックが発生すると、絶縁破壊を起こす可能性が生じる。エポキシ樹脂が熱劣化すると、エポキシ樹脂が蒸発し質量が減少することより、変圧器の固有振動数が変化する。
そこで、乾式変圧器に対しても振動解析により、異常や劣化の診断ができる。鉄心と巻線を合わせて樹脂硬化させたモールド変圧器の場合はその容器表面の振動を測定する。
鉄心と巻線を別々に樹脂硬化させたモールド変圧器や、巻線のみを樹脂硬化させたモールド変圧器の場合は、鉄心と巻線が個別に振動することから、鉄心と巻線の表面を個別に振動測定することが可能であり、油入変圧器と同様に鉄心と巻線の異常や劣化の診断をそれぞれ実施できる。
一例として、図1に示す解析器26の記憶装置に健全な初期状態の変圧器の鉄心や巻線の個別振動状態を記録しておき、実際の測定結果と対比することで変化した割合に応じて当該変圧器の劣化度がどの程度であるのか、また、変圧器としての寿命に達したか否か診断できる。
"Analysis of dry transformers"
Next, diagnosis by vibration analysis of the dry type transformer will be described.
The dry type transformer is also called a molded transformer, and is made by immersing and hardening the inside of the transformer with an insulating epoxy resin instead of the insulating oil. Therefore, the main deterioration factor of the dry type transformer is the thermal deterioration of the epoxy resin (see Non-Patent Document 8).
When the epoxy resin is thermally deteriorated, the mechanical strength is reduced, and when a crack is generated due to an external force such as a short circuit current or an earthquake, a possibility of causing an insulation breakdown occurs. When the epoxy resin is thermally deteriorated, the natural frequency of the transformer is changed due to the evaporation of the epoxy resin and the decrease in mass.
Therefore, it is possible to diagnose abnormalities and deterioration by vibration analysis also for dry type transformers. In the case of a molded transformer in which an iron core and a winding are combined and resin-cured, the vibration of the container surface is measured.
In the case of a molded transformer in which the core and the winding are resin-hardened separately or in the case of a molded transformer in which only the wire is resin-hardened, the iron core and the winding vibrate separately. Vibration can be measured individually, and as with oil-filled transformers, diagnosis of abnormality and deterioration of iron core and winding can be performed.
As an example, the individual vibration state of the iron core or the winding of the transformer in a sound initial state is recorded in the storage device of the analyzer 26 shown in FIG. 1 and the ratio changed by comparing with the actual measurement result. It is possible to diagnose whether the degree of deterioration of the transformer is, and whether or not the life as a transformer has been reached.

上記した従来の課題を解決するために、本実施形態では稼働状態の変圧器において、その振動の振幅および位相を測定し電源電圧の振幅や位相と比較することにより変圧器内部の異常および劣化を診断する方法である。診断のために特別な電流を流す必要はない。
本実施形態では、変圧器の鉄心や巻線を振動させる加振力の源として、稼働状態の変圧器の通電により生じる電磁力だけを用いる。そのため、先の特許文献2において励磁周波数を商用周波数だけに限ることと等しく、本実施形態の診断方法は特許文献2記載の方法と一部類似はしているが、特許文献2においては、励磁周波数を段階的に変化させた周波数毎の測定結果が一組となり、固有周波数を解析する方法である。
一方、本実施形態の診断方法では、加振の原因となる通電の周波数は基本的には電源周波数の2倍のただ1つだけであり、大きな相違点である。この加振力に着目して鉄心や巻線の締め付け状態や、エポキシ樹脂の熱劣化の状態に応じて発生する種々の振動を捉えて通電の周波数と比較することが重要である。
In order to solve the above-described conventional problems, in the present embodiment, in the operating transformer, the amplitude and phase of the vibration are measured and compared with the amplitude and phase of the power supply voltage, and the abnormality and deterioration inside the transformer are It is a method of diagnosis. There is no need to apply a special current for diagnosis.
In the present embodiment, only the electromagnetic force generated by energization of the operating transformer is used as a source of excitation force that vibrates the iron core or the winding of the transformer. Therefore, the prior art Patent Document 2 is equivalent to limiting the excitation frequency to only the commercial frequency, and the diagnosis method of the present embodiment is partially similar to the method described in Patent Document 2, but in Patent Document 2 The measurement results for each frequency in which the frequency is changed stepwise are one set, and this is a method of analyzing the natural frequency.
On the other hand, in the diagnostic method of the present embodiment, the frequency of energization causing the vibration is basically only one, which is twice the power supply frequency, which is a big difference. It is important to capture various vibrations generated depending on the tightening condition of the iron core or the winding and the condition of heat deterioration of the epoxy resin focusing on this exciting force and compare it with the frequency of energization.

また、本実施形態において加振の原因となる電源電流はただ1つの振動数成分であるが、電源電圧の歪み、発生する磁力の歪み、伝達される力の歪みなどが関与して色々なモードの振動が誘起されてくると考えられる。
電源電圧は理想的には正弦波であるが、電力供給段階や、負荷側接続機器の内容によって正弦波が歪んで加振力自身が高調波を含むことが考えられる。
鉄心振動については励磁電流により発生する磁界が鉄心振動の源となるが、鉄心の磁気飽和曲線の非線形性により磁束密度は高調波を含む。また、鉄心の磁化と磁歪の非線形性もあり、電源電圧とは異なる周波数成分の加振力も誘起されることになる。
巻線振動の場合は、巻線の漏れ磁束と巻線に流れる電流からローレンツ力が発生するが、巻線の巻き方の配線や偏りなどのために漏れ磁束は正弦波的な変化から歪み、電源電圧とは異なる周波数成分の加振力も誘起される。
Further, although the power supply current causing the vibration in the present embodiment is only one frequency component, various modes are involved due to distortion of power supply voltage, distortion of generated magnetic force, distortion of transmitted force, and the like. It is thought that the vibration of is induced.
The power supply voltage is ideally a sine wave, but it is conceivable that the excitation wave itself includes harmonics due to distortion of the sine wave depending on the power supply stage and the contents of the load side connection device.
With regard to core vibration, the magnetic field generated by the excitation current is the source of core vibration, but the magnetic flux density includes harmonics due to the non-linearity of the magnetic saturation curve of the core. In addition, since there is non-linearity between the magnetization of the iron core and the magnetostriction, an excitation force of a frequency component different from the power supply voltage is also induced.
In the case of winding vibration, Lorentz force is generated from the leakage flux of the winding and the current flowing in the winding, but the leakage flux is distorted from the sinusoidal change due to the wiring and the bias of the winding method, An excitation force of a frequency component different from the power supply voltage is also induced.

一般の変圧器において鉄心は薄い電磁鋼板を積層して、ねじ止めされるかバンドにて締付けられている。また、巻線は締付けねじを通じて締付けられている。締付け力を受ける鉄心や巻線は一種のばねに相当し、そのばね定数は締付け力により変化することや、締付け力の不均一性により、締付け力は歪んで伝達され、加振力とは異なる周波数成分の振動を誘起する。よって、診断のために特別な電流を流さずとも、電源周波数の2倍とは異なる周波数成分の固有振動モードに関する情報も得ることが可能である。
その場合、加振力の主な周波数成分は電源周波数の整数倍(電源系の固有振動数と呼ぶ)であり、奇数倍成分より偶数倍成分の方が大きく、健全な変圧器において多くの場合は2倍成分が最も大きい。また、成分は小さいが電源周波数の整数倍以外のあらゆる周波数成分も含まれ、鉄心や巻線の自由振動を励起する。
In general transformers, iron cores are laminated with thin electromagnetic steel plates and screwed or clamped with a band. Also, the winding is tightened through a clamping screw. The iron core or winding that receives clamping force corresponds to a kind of spring, and the spring constant is changed due to the clamping force and non-uniformity of the clamping force causes the clamping force to be distorted and transmitted, which is different from the excitation force It induces oscillations of frequency components. Therefore, it is possible to obtain information on natural vibration modes of frequency components different from twice the power supply frequency without supplying a special current for diagnosis.
In that case, the main frequency component of the excitation force is an integral multiple of the power supply frequency (referred to as the natural frequency of the power supply system), and the even-multiple component is larger than the odd-multiple component. Is the largest of the double components. In addition, it contains a small component but also any frequency component other than an integral multiple of the power supply frequency, and excites free vibration of the iron core and the winding.

また、変圧器の劣化が進むと締付け力は弱まり、加振周波数とは異なる周波数の振動成分が大きくなる。そこで、2倍振動振幅(電源周波数50Hzの場合、100Hzのこと)に対しより他の振動成分の振動振幅が大きくなることを捉えて巻線部に使用されている絶縁物が劣化していると診断することができる。
この場合、他の固有振動は歪んで伝達された加振力により決まった位相遅れを有するようになると考えられる。よって、位相情報と対になって解析することにより、位相が一定しない背景雑音は除去して、通電電流により発生する振動に限った他の振動成分の振幅の増大を捉えることができる。
稼働中の変圧器から検出した振動スペクトルのうち可聴音領域内の他の振動成分の振幅が、通電電流による加振力の周波数成分の大きさに対して大きくなることを捕捉して稼働中の変圧器の状態を解析することは、先のような変圧器内部の異常および劣化を診断する方法である。
In addition, as the deterioration of the transformer progresses, the tightening force is weakened, and the vibration component of a frequency different from the excitation frequency is increased. Therefore, it is assumed that the insulator used in the winding part is deteriorated by catching that the vibration amplitude of the other vibration component becomes larger than the double vibration amplitude (about 100 Hz for the power supply frequency of 50 Hz). It can be diagnosed.
In this case, the other natural vibrations are considered to be distorted and to have a fixed phase delay due to the transmitted excitation force. Therefore, by analyzing in a pair with the phase information, it is possible to remove background noise whose phase is not constant and to grasp an increase in the amplitude of another vibration component limited to the vibration generated by the supplied current.
Of the vibration spectrum detected from the transformer in operation, the amplitude of the other vibration component in the audible sound area is larger than the magnitude of the frequency component of the excitation force by the energizing current, and it is in operation Analyzing the state of the transformer is a method of diagnosing abnormalities and deterioration inside the transformer as described above.

診断のために特別な電流を流さず、変圧器稼働時の騒音を測定するだけで変圧器内部の異常および劣化を診断する方法は従来既に提案されている。特許文献3は、機械の音圧を検出し、あらかじめ設定した基準スペクトルと比較して機械の異常を診断する方法を開示している。また、特許文献4には変圧器に例えば鉄心や巻線を締め付けているボルトが緩むなどして異常が生じると機器の発する音が変化し、各周波数成分の音圧レベルが正常時の範囲から大きく外れると記載されている。これらの診断方法は正常時の音響パターンと異常時の音響パターンを比較して差が大きい場合に異常や劣化が生じていると診断する方法であり、モード解析とは全く異なる解析方法である。   A method of diagnosing abnormalities and deterioration inside the transformer only by measuring noise during transformer operation without supplying a special current for diagnosis has already been proposed. Patent Document 3 discloses a method of detecting a sound pressure of a machine and diagnosing a machine abnormality by comparing it with a preset reference spectrum. Further, according to Patent Document 4, when an abnormality occurs such as loosening a bolt tightening an iron core or a winding in a transformer, for example, the sound emitted by the device changes, and the sound pressure level of each frequency component changes from the normal time range It is described that it deviates greatly. These diagnostic methods are methods of comparing an acoustic pattern at the normal time and an acoustic pattern at the abnormal time to diagnose that an abnormality or deterioration occurs when the difference is large, and is an analysis method completely different from the modal analysis.

正常時と異常時の音響パターンを比較する方法は、特許文献4に記載のように音圧レベルの上限閾値と下限閾値を設定して、その範囲を超えるデータの割合により診断することになるが、この場合、背景雑音が重畳して誤判定する可能性が生じ、上限閾値と下限閾値の幅を大きくとる必要が生じるため診断の精度が低下してしまう問題がある。   As described in Patent Document 4, the upper and lower sound pressure level threshold values are set as a method of comparing the normal and abnormal sound patterns, and diagnosis is made based on the proportion of data exceeding that range. In this case, background noise may be superimposed to cause an erroneous determination, and there is a need to increase the width between the upper threshold and the lower threshold.

本実施形態の場合は、通電電流による加振力の位相を基準とするので、通電電流に無関係な背景雑音を排除して診断精度の低下を防ぐことができる。また、強制振動の位相差φは、測定系の増幅の具合により変化する振幅情報に比較し、通電電源の位相と比較することにより値を見積もることが容易に可能である。
さらに、先のように求めた機械的振動の位相を健全な変圧器の振動位相と比較して稼働中の変圧器の状態を解析するならば、位相差について変圧器の初期データと比較して変化があれば、何らかの内部異常または経年変化を生じたと診断できる。ただし、初期データは負荷電流依存性を測定し、鉄心振動と巻線振動のバランスを調べておく必要がある。また、同型の変圧器を用いて後日初期データを採取することもできる。
In the case of the present embodiment, since the phase of the excitation force due to the supplied current is used as a reference, background noise unrelated to the supplied current can be eliminated to prevent a decrease in diagnostic accuracy. Further, the phase difference φ of the forced vibration can be easily estimated by comparing it with the phase of the energizing power source in comparison with the amplitude information that changes depending on the degree of amplification of the measurement system.
Furthermore, if the phase of the mechanical vibration determined as described above is compared with the vibration phase of the sound transformer to analyze the state of the operating transformer, the phase difference is compared with the initial data of the transformer. If there is a change, it can be diagnosed that some internal abnormality or aging has occurred. However, it is necessary to measure the load current dependency and to examine the balance of iron core vibration and winding vibration in the initial data. Also, it is possible to collect initial data later by using a transformer of the same type.

非特許文献6には、音響的手法により変圧器を異常診断する技術が記載されている。それは変圧器内部で部分放電が起きた際に、同時に発生する超音波をAEセンサで検知するものであり、前項で述べた機械的振動における実験モード解析で機械の調子を判断する方法とは異なる。
また、非特許文献6には、周波数応答解析(FRA)による変圧器の診断手法が記載されている。非特許文献6でいう周波数応答は正弦波電圧を印加し、その周波数を掃引して伝達関数を測定する方法である。変圧器の鉄心やコイルが締付け力の低下や外力により、ずれを生じたり、接地のはずれが生じたりした場合に、電気的インピーダンスが変化するので、短絡インピーダンスや巻線漏れインダクタンスが変化することに着目した診断手法であり、やはり前述の機械的振動における実験モード解析で機械の調子を判断する方法とは異なる。
Non-Patent Document 6 describes a technology for diagnosing abnormality of a transformer by an acoustic method. That is, when partial discharge occurs inside the transformer, the simultaneously generated ultrasonic wave is detected by the AE sensor, which is different from the method of judging the mechanical condition by the experimental modal analysis in mechanical vibration described in the previous paragraph .
Further, Non-Patent Document 6 describes a method of diagnosing a transformer by frequency response analysis (FRA). The frequency response in Non-Patent Document 6 is a method of applying a sine wave voltage and sweeping the frequency to measure a transfer function. The electrical impedance changes when the transformer core or coil is dislocated or the ground is disconnected due to a decrease in clamping force or external force, so that the short circuit impedance or the winding leakage inductance changes. This is a diagnostic method that focuses on, and is different from the above-described method of determining the mechanical condition by the experimental modal analysis in mechanical vibration described above.

(実施例1)
50Hzで稼働中(負荷率10%)の油入変圧器(3相、定格容量200kVA、定格電流550A、稼働9年、三菱電機社製RA−TN形)のタンク壁面中央付近におけるレーザー変位計(キーエンス株式会社製LK−G5000)の出力波形を測定した。この変圧器タンクの壁面は高さ約80cmであり、振動が最も小さい領域はタンク壁面中央部であり、タンク振動の節と考えられる。
図4にレーザー変位計の出力波形の一例を示す。図4に示す波形は約10Hzの基本波形に電源周波数の2倍である100Hzの周波数の波形が重畳された波形を示している。
図4に示す波形をフーリエ変換して得た波形の一例を図5に示す。図5において、約10Hzの部分に現れている大きなピーク波形は変圧器に当たる風の影響によるノイズと判断して以下の解析では削除した。
変圧器の電源周波数は50Hzであり、その整数倍の周波数にピークを持つ。電源周波数の2倍の100Hz成分が加振力の基本であり、100Hzの整数倍の成分は電源系による強制振動である。図5には約10Hzの大きな振動もみられるが、それは電源系以外の測定時の風などによる強制振動であるので、今後の解析にはこの振動は除外した。
Example 1
Laser displacement meter (3 phase, rated capacity 200kVA, rated current 550A, 9 years in operation, Mitsubishi Electric RA-TN type) operating at 50Hz (10% load factor) near the center of the tank wall The output waveform of Keyence Corporation LK-G5000) was measured. The wall of the transformer tank is about 80 cm high, and the area with the least vibration is the center of the tank wall, which is considered to be a node of the tank vibration.
FIG. 4 shows an example of the output waveform of the laser displacement meter. The waveform shown in FIG. 4 is a waveform in which a waveform of a frequency of 100 Hz which is twice the power supply frequency is superimposed on a basic waveform of about 10 Hz.
An example of a waveform obtained by Fourier-transforming the waveform shown in FIG. 4 is shown in FIG. In FIG. 5, the large peak waveform appearing in the portion of about 10 Hz was judged as noise due to the wind impact on the transformer and was eliminated in the following analysis.
The power supply frequency of the transformer is 50 Hz and has a peak at a frequency that is an integral multiple of that. The 100 Hz component which is twice the power supply frequency is the basis of the excitation force, and the component which is an integral multiple of 100 Hz is a forced vibration by the power supply system. Although a large vibration of about 10 Hz is also seen in FIG. 5, this vibration is excluded from the analysis in the future because it is a forced vibration due to wind or the like at the time of measurement other than the power supply system.

次に、ロックインアンプを用いて図4のレーザー変位計出力波形から電源周波数の2倍波(100Hzの成分)を抽出した波形が図6の波形である。振幅は1に規格化してある。この変圧器振動は、巻線振動のほかに鉄心振動を含む。測定時の負荷率は約10%であった。   Next, a waveform obtained by extracting the second harmonic (100 Hz component) of the power supply frequency from the laser displacement meter output waveform of FIG. 4 using a lock-in amplifier is shown in FIG. The amplitude is normalized to one. This transformer vibration includes core vibration in addition to winding vibration. The loading factor at the time of measurement was about 10%.

次に、電源電流波形を2乗して100Hz成分の振幅を±1に規格化した波形(点線)と変圧器振動(実線)の位相差を図7に示す。位相差の数値は2位相ロックインアンプを使用して求めることもできる。位相差に関して負荷率を10%とした初期データと比較して変化があれば、何らかの内部異常または経年変化を生じたと診断できる。   Next, FIG. 7 shows a phase difference between a waveform (dotted line) obtained by squaring the power supply current waveform and the amplitude of the 100 Hz component normalized to ± 1, and a transformer vibration (solid line). The phase difference value can also be determined using a two phase lock in amplifier. If there is a change in the phase difference as compared to the initial data in which the load factor is 10%, it can be diagnosed that some internal abnormality or aging has occurred.

(実施例2)
50Hzで稼働中(負荷率60%)の油入変圧器(3相、定格容量12MVA、1次側11kV、2次電圧3.45kV、稼働33年)のタンク壁面中央付近におけるAEセンサの出力波形をフーリエ変換して横軸を周波数、縦軸に振幅を線形スケールでプロットした結果を図9に示す。電源周波数の整数倍のピークが現れている。
変圧器の劣化が進むと、高周波成分の割合が高くなることから、変圧器のタンクの振動スペクトルのうち、可聴帯域内で高次の振動成分の振幅が、通電電流による加振力の周波数(電源周波数の2倍)成分の大きさに対して大きくなることを捉えたならば、変圧器の内部異常診断および劣化診断を行うことができる。
(Example 2)
Output waveform of AE sensor near the tank wall center of oil filled transformer (3 phase, rated capacity 12MVA, primary side 11kV, secondary voltage 3.45kV, 33 years of operation) operating at 50Hz (load factor 60%) FIG. 9 shows the result of Fourier transform of X.sup.2 with the horizontal axis representing frequency and the vertical axis representing amplitude on a linear scale. A peak appears that is an integral multiple of the power supply frequency.
As the deterioration of the transformer progresses, the ratio of high frequency components increases. Therefore, in the vibration spectrum of the tank of the transformer, the amplitude of the high order vibration component in the audible band is the frequency of the excitation force by the energizing current ( If an increase in the magnitude of the component of twice the power supply frequency is detected, internal abnormality diagnosis and deterioration diagnosis of the transformer can be performed.

図10は図9のグラフに示す測定波形について、縦軸を対数目盛として表示し直した結果を示す。また、AEセンサによるタンク側壁の測定位置をタンク側壁(高さ260cm)の中央位置から約65cm下げて測定した結果を図11に示し、変圧器に対する負荷を30%に設定して測定した結果を図12に示す。
図10に示すように一点鎖線のピークは鉄心の振動によるピークを示し、鎖線のピークはタンクの振動によるピークを示し、二点鎖線のピークは巻線の振動によるピークを示すが、この段階の測定結果では、それぞれどの部位の振動モードであるかは不明である。
電源周波数が50Hzの場合、図10に示すように50Hzの整数倍の周波数にピークが現れる。電源周波数の2倍の100Hz成分が加振力の基本であり、100Hzの整数倍の成分は電源系による強制振動である。振幅を線形スケールでプロットした図9には電源系による強制振動しか目立ったピークは見られない。しかし、振幅を対数表示した図10には50Hzの整数倍の周波数以外にもピークが見えており、機械系の振動と考えられる。
図10に示される機械系の振動は主に鉄心振動と巻線振動とタンク振動の3成分よりなるが、この段階の測定結果では、それぞれどの部位の振動モードであるかは不明である。
FIG. 10 shows the result of re-displaying the measured waveform shown in the graph of FIG. 9 as a logarithmic scale on the vertical axis. Also, the measurement position of the tank side wall by the AE sensor was lowered by about 65 cm from the center position of the tank side wall (height 260 cm), and the result is shown in FIG. It is shown in FIG.
As shown in FIG. 10, the peak of the alternate long and short dash line shows the peak due to the vibration of the iron core, the peak of the dashed line shows the peak due to the tank vibration and the peak of the alternate long and two short dashed line shows the peak due to the winding vibration. In the measurement results, it is unclear which part of the vibration mode it is.
When the power supply frequency is 50 Hz, as shown in FIG. 10, a peak appears at a frequency that is an integral multiple of 50 Hz. The 100 Hz component which is twice the power supply frequency is the basis of the excitation force, and the component which is an integral multiple of 100 Hz is a forced vibration by the power supply system. In FIG. 9 in which the amplitude is plotted on a linear scale, a peak in which only forced oscillation due to the power supply system is noticeable is seen. However, in FIG. 10 in which the amplitude is logarithmically displayed, peaks are also seen in addition to the frequency of integral multiples of 50 Hz, which is considered to be mechanical system vibration.
The vibration of the mechanical system shown in FIG. 10 mainly includes three components of iron core vibration, winding vibration and tank vibration, but it is unclear in which part of the vibration mode it is from the measurement results at this stage.

負荷率60%において測定位置を変えた2つの測定結果(図10と図11のグラフ)について、測定された機械系の固有振動とその振動強度を以下の表1にまとめて示す。以下の表1、表2において、−は振幅を観察できなかったことを意味し、以下振幅の大きさに応じて+の数を増加させて示した。   For two measurement results (graphs in FIG. 10 and FIG. 11) in which the measurement position was changed at a load factor of 60%, the measured natural vibrations of the mechanical system and the vibration strength thereof are summarized in Table 1 below. In Tables 1 and 2 below,-means that the amplitude could not be observed, and the following is shown by increasing the number of + according to the magnitude of the amplitude.

Figure 0006519810
Figure 0006519810

測定位置を変えることにより振動強度が変化した振動モードはタンク振動と考えられ、残りは鉄心振動と巻線振動と考えられる。図11に示す結果と図10に示す結果の対比から、37Hz,62Hz,99Hz,137Hz,174Hz,268Hz,329Hz,398Hz,478Hz,566Hzの各振動はタンク振動であることと、残りの振動成分は鉄心と巻線に関する振動であることがわかる。   The vibration mode in which the vibration intensity is changed by changing the measurement position is considered as tank vibration, and the rest are considered as iron core vibration and winding vibration. From the comparison between the results shown in FIG. 11 and the results shown in FIG. 10, each vibration of 37 Hz, 62 Hz, 99 Hz, 137 Hz, 174 Hz, 268 Hz, 329 Hz, 398 Hz, 478 Hz, 566 Hz is tank vibration and the remaining vibration component is It turns out that it is a vibration about an iron core and a winding.

測定位置をタンク壁面中央として負荷率を変えた2つの測定結果(図10と図12のグラフ)について、測定された鉄心振動と巻線振動に関する振動強度を以下の表2に示す。   For two measurement results (graphs in FIG. 10 and FIG. 12) in which the measurement position is at the center of the tank wall and the load factor is changed, the measured vibration strengths of iron core vibration and winding vibration are shown in Table 2 below.

Figure 0006519810
Figure 0006519810

負荷率を変えることにより振動強度が変化した振動モードは巻線振動と考えられ、残りは鉄心振動と考えられる。図12に示す結果から、23Hz、78Hz、97Hzは鉄心、141Hz,582Hzは巻線の振動であることがわかる。
この実施例は1方向の振動を測定するセンサ(1次元センサ)を用いた測定であるが、3次元センサを用いた場合も同様な測定および解析を行うことができる。
The vibration mode in which the vibration intensity is changed by changing the load factor is considered to be a winding vibration, and the rest is considered to be an iron core vibration. From the results shown in FIG. 12, it can be seen that 23 Hz, 78 Hz, and 97 Hz indicate the iron core, and 141 Hz and 582 Hz indicate the vibration of the winding.
Although this embodiment is a measurement using a sensor (one-dimensional sensor) that measures vibration in one direction, similar measurement and analysis can be performed when a three-dimensional sensor is used.

高次の振動モードについての振動数は、振動波形をフーリエ変換して見積もることができる。しかし、高次の振動モードは特に劣化のあまり進行していない変圧器においては振幅が小さいので捉えにくい。そこで、補償法と呼ばれる電源位相に同期した信号処理を行うことが好ましい。
対象となる物理量以外に複数の要因のノイズ成分が含まれるとき、差動法で取り除けないノイズ成分に主たる感度を持つ測定系を用いてこれを取り除く。測定量から測定量を超えない範囲で一定の量を差し引き、残りの部分を偏位法や零位法などにより測定することにより、測定精度を高めることができる。
The frequency for higher order vibration modes can be estimated by Fourier transforming the vibration waveform. However, higher-order vibration modes are difficult to catch because they have small amplitudes, especially in transformers that are not well developed. Therefore, it is preferable to perform signal processing in synchronization with a power supply phase called a compensation method.
When noise components of a plurality of factors are included in addition to the physical quantity to be processed, this is removed using a measurement system having a main sensitivity to noise components that can not be removed by the differential method. The measurement accuracy can be enhanced by subtracting a fixed amount within the range not exceeding the measured amount from the measured amount and measuring the remaining part by the displacement method or the zero method.

周波数の測定では、図13に示すように混合器30を用いて周波数の混合(ビート法)により、標準周波数fから測定周波数fを引き、その差の周波数fを測定する。この周波数fは中間周波数fIFと呼ばれ、増幅する周波数が下がるので、増幅が容易となり測定精度が高くなるとともに、高い周波数の測定を容易にしている。ここで用いる標準周波数を、局部発信周波数fLOという。
信号に含まれる周波数fと局部発信周波数fLOを一致させると、その差はゼロとなる。すなわち、初めからfとfLOが一致するようにfLOを選び、元の信号をベースバンドである周波数ゼロに直接落とす方法をホモダインという。
また、信号に含まれる周波数fと局部発信周波数fLOの和または差の中間周波数fIFが一定になるよう、局部発信周波数fLOを選ぶこともできる。また、信号を中間周波数に変換する信号処理をヘテロダインという。
The measurement of frequency, the mixing frequency (beat) method using a mixer 30 as shown in FIG. 13, pull the measurement frequency f from the standard frequency f s, to measure the frequency f B of the difference. The frequency f B is called the intermediate frequency f IF, the frequency to be amplified decreases, together with the measurement accuracy becomes easy amplification increases to facilitate the measurement of high frequency. The standard frequency used here is called local oscillation frequency f LO .
When the frequency f s included in the signal and the local oscillation frequency f LO are matched, the difference is zero. That is, the method of selecting f LO so that f s and f LO match from the beginning and directly dropping the original signal to the frequency zero which is the base band is called homodyne.
Also, the local transmission frequency f LO can be selected so that the intermediate frequency f IF of the sum or difference of the frequency f s contained in the signal and the local transmission frequency f LO is constant. Further, signal processing for converting a signal to an intermediate frequency is called heterodyne.

以上の方法で信号に含まれる周波数fを見いだせれば、ロックインアンプを用いて大きな雑音に埋もれた微小な目的信号の生波形を計測することができる。
また、標準周波数はmHz〜百kHzまで可変であるので、周波数を掃引して共振点を見つけるというPLL(フェーズロックドループ:位相同期回路)という手法を用いて解析することもできる。
さらに、標準周波数の位相をフェーズシフタ(Phase Shifter)で調節すると測定周波数の位相情報も解析することも可能である。
If the frequency f s contained in the signal can be found by the above method, it is possible to measure the raw waveform of a minute target signal buried in large noise using a lock-in amplifier.
Further, since the standard frequency is variable from mHz to 100 kHz, analysis can also be performed using a method called PLL (phase locked loop: phase locked loop) in which the frequency is swept to find a resonance point.
Furthermore, it is also possible to analyze the phase information of the measurement frequency by adjusting the phase of the standard frequency with a phase shifter.

(実施例3)
定格周波数60Hzで稼働中(負荷率約10%)の油入変圧器(3相、定格容量10MVA、一次側定格電圧11kV、二次側定格電圧3.45kV、絶縁油量5300リットル、稼働開始1975年)を測定対象として変圧器タンクの壁面の種々の位置に振動センサを設置し、変圧器タンクの振動を測定した。振動センサにはPCB社((株)東陽テクニカ)製三軸加速度計(356A17)、電流測定にはクランプ電流計を用い、データロガーにはFFTアナライザ(オロス社製OR38V3−32)を用いた。
(Example 3)
Oil-filled transformer (3 phase, rated capacity 10MVA, primary side rated voltage 11kV, secondary side rated voltage 3.45kV, insulating oil amount 5300 liters, operating start at 1975) with rated frequency 60Hz in operation (load factor approx. 10%) Vibration sensors were installed at various positions on the wall of the transformer tank, and the vibration of the transformer tank was measured. As a vibration sensor, a three-axis accelerometer (356A17) manufactured by PCB (Toyo Technica) was used, a clamp ammeter was used for current measurement, and an FFT analyzer (OR38V3-32 manufactured by Oros) was used as a data logger.

変圧器タンクの概要を図14に示す。ただし、図14には変圧器に電力を入出力するためのブッシングおよび配線は省略している。
この変圧器タンク31は横幅2200mm、高さ2000mm、奥行き800mmの鋼板製の直方体状の中空容器であって、その高さを約3等分する上下2箇所の位置にそれぞれ金属製の腰巻き状の補強ステー32、33が設けられている。
変圧器タンク31の周壁において補強ステー32より上の部分が上部周壁31aから構成され、変圧器タンク31の周壁において補強ステー32より下の部分が中部周壁31bから構成され、変圧器タンク31の周壁において補強ステー33より下の部分が下部周壁31cから構成されている。
この変圧器31において補強ステー32、33の部分は振動が制限される位置となるため、振動センサを取り付けて振動を計測する位置として以下の18箇所を候補とした。
The outline of the transformer tank is shown in FIG. However, the bushing and wiring for inputting and outputting electric power to and from the transformer are omitted in FIG.
The transformer tank 31 is a rectangular parallelepiped hollow container made of steel plate having a width of 2200 mm, a height of 2000 mm, and a depth of 800 mm, and metal waist wraps at two upper and lower positions dividing the height into about three. Reinforcing stays 32, 33 are provided.
A portion above the reinforcement stay 32 in the peripheral wall of the transformer tank 31 is constituted by the upper peripheral wall 31a, and a portion below the reinforcement stay 32 in the peripheral wall of the transformer tank 31 is constituted by the middle peripheral wall 31b The lower part of the reinforcement stay 33 is composed of the lower peripheral wall 31c.
Since the portions of the reinforcement stays 32 and 33 in the transformer 31 are at positions where the vibration is limited, the following eighteen positions are set as candidates for measuring the vibration by attaching a vibration sensor.

この変圧器タンク31において図14に数字の1〜16を○印で囲む位置のそれぞれに振動センサを取り付けて振動を計測することができる。○印で囲む数字の1の位置は上部周壁31aの左側壁面を示し、○印で囲む数字の2の位置は上部周壁31aの正面壁の左端側に相当する位置(正面壁の左端から約40cm離れた位置付近)を示し、○印で囲む数字の3の位置は上部周壁31aの正面壁の右端側に相当する位置(正面壁の右端から約40cm離れた位置付近)を示す。○印で囲む数字の4の位置は上部周壁31aの右側壁面を示し、○印で囲む数字の5の位置は上部周壁31aの背面壁の右端側に相当する位置(背面壁の右端から約40cm離れた位置付近)を示し、○印で囲む数字の6の位置は上部周壁31aの背面壁の左端側に相当する位置(背面壁の左端から約40cm離れた位置付近)を示す。   In this transformer tank 31, vibration sensors can be attached to the positions surrounding the numbers 1 to 16 in FIG. The position of number 1 enclosed by ○ indicates the left side wall surface of upper peripheral wall 31a, and the position of number 2 enclosed by circle 相当 corresponds to the left end side of the front wall of upper peripheral wall 31a (approximately 40 cm from the left end of the front wall The position of the numeral 3 surrounded by ○ indicates the position corresponding to the right end side of the front wall of the upper peripheral wall 31a (around 40 cm from the right end of the front wall). The position of number 4 enclosed by ○ indicates the right side wall of upper peripheral wall 31a, and the position of number 5 enclosed by ○ corresponds to the right end of the back wall of upper peripheral wall 31a (about 40 cm from the right end of the back wall) The position of number 6 surrounded by ○ indicates the position corresponding to the left end side of the back wall of the upper peripheral wall 31a (around 40 cm from the left end of the back wall).

ここで例示したように、振動センサを取り付ける位置は、補強ステー32より下方の中部周壁31bにおいて○印で囲む数字の7、8、9、10の位置と補強ステー33より下方の下部周壁31cにおいて○印で囲む数字の13、14、15、16のいずれの位置であっても良い。なお、中部周壁31bの背面壁側の取り付け位置と下部周壁31cの背面壁側の取り付け位置は図14では図示できないため略しているが、数字の5、6を○印で囲む取り付け位置に対応する中部周壁31bの背面壁側と下部周壁31cの背面壁側にそれぞれ設定される。
これらの振動センサ取付候補位置において、以下の試験では数字の4を○印で囲む位置に相当する上部右側壁に振動センサを設置して振動を計測した。
As illustrated here, the position where the vibration sensor is attached is at the positions 7, 8, 9 and 10 of the numbers surrounded by circles in the middle peripheral wall 31b below the reinforcement stay 32 and the lower peripheral wall 31c below the reinforcement stay 33. It may be any position of numbers 13, 14, 15, 16 enclosed by o marks. The mounting position on the back wall side of the middle peripheral wall 31b and the mounting position on the rear wall side of the lower peripheral wall 31c are omitted because they can not be illustrated in FIG. 14, but they correspond to the mounting positions surrounding the numbers 5 and 6 with ○ marks. The back wall side of the middle peripheral wall 31 b and the back wall side of the lower peripheral wall 31 c are respectively set.
At these vibration sensor mounting candidate positions, in the following tests, vibration sensors were installed on the upper right side wall corresponding to the positions surrounding the number 4 with circle marks to measure the vibration.

なお、この例で試験した変圧器の内部には、図15に示すように3本の脚部35を上下のヨーク部36、37で連結した井桁構造の鉄心38が収容されている。図15において脚部35に巻回されている一次側巻線と二次側巻線については記載を略している。
この鉄心38においては、図15(A)に示すねじりモードと図15(B)に示す曲げモード1と図15(C)に示す曲げモード2の3種の振動モードをとることを想定することができる。図15に示すモード解析は、水野末良他による「変圧器鉄心の固有振動特性」(平成25年、電気学会全国大会5−195)による。
図15(A)に示すねじりモードの変圧器の場合、図14に示す数字の2、3、5、6を○印で囲む位置に振動センサを設置することにより鉄心振動をタンク壁面で捉えることができると考えられる。その場合、数字の2と3の位置は逆方向に、数字の5と6の位置は逆方向に、数字の2と6の位置は同方向に、数字の3と5の位置は同方向に変位していることを確認できれば、鉄心はねじりモードで振動していることが分かる。同様に、図15(B)に示すように数字の8、9、11、12の位置に振動センサを設置して変位を確認すれば、モード1で振動していることがわかる。同様に、図15(C)に示すように数字の7、10の位置に振動センサを設置して変位を確認すれば、モード2で振動していることがわかる。
鉄心の固有振動数に振動モードを同定することができると、その固有振動数から鉄心の締付け力が算出できる。ただし、鉄心の締付け力にばらつきがある場合、固有振動のピークは広がる。逆に、固有振動数の広がり、例えば半値幅から締付け力のばらつきを評価することも可能である。巻線の固有振動ピークが広がりを持っている場合も同様な評価が可能である。ピーク幅が広がることは鉄心または巻線の劣化と関係するが、どれほどのピーク幅が劣化診断の閾値になるかは、変圧器ごとの設計によるので、変圧器ごとに決める必要がある。
In the inside of the transformer tested in this example, as shown in FIG. 15, an iron core 38 of a well girder structure in which three legs 35 are connected by upper and lower yokes 36 and 37 is accommodated. The description of the primary side winding and the secondary side winding wound around the leg 35 in FIG. 15 is omitted.
In this iron core 38, it is assumed that three vibration modes, that is, the torsion mode shown in FIG. 15 (A) and the bending mode 1 shown in FIG. 15 (B) and the bending mode 2 shown in FIG. Can. The modal analysis shown in FIG. 15 is based on “natural vibration characteristics of transformer iron core” (2013, National Institute of Electrical and Electronics Engineers 5-195) according to Sueyoshi Mizuno et al.
In the case of the torsion mode transformer shown in FIG. 15 (A), by disposing a vibration sensor at a position surrounding circled numbers 2, 3, 5 and 6 shown in FIG. It is believed that In that case, the numbers 2 and 3 are in the opposite direction, the numbers 5 and 6 are in the opposite direction, the numbers 2 and 6 are in the same direction, and the numbers 3 and 5 are in the same direction. If displacement can be confirmed, it can be understood that the iron core vibrates in the torsion mode. Similarly, as shown in FIG. 15 (B), if the vibration sensor is installed at the positions 8, 9, 11 and 12 of the numerals and the displacement is confirmed, it can be understood that vibration is performed in mode 1. Similarly, as shown in FIG. 15C, if the vibration sensor is installed at the positions 7 and 10 of the numerals and the displacement is confirmed, it can be understood that vibration is performed in mode 2.
If the vibration mode can be identified to the natural frequency of the iron core, the tightening force of the iron core can be calculated from the natural frequency. However, if there is a variation in the tightening force of the iron core, the natural vibration peak will spread. Conversely, it is also possible to evaluate the spread of the natural frequency, for example, the variation in tightening force from the half width. The same evaluation is possible when the natural vibration peak of the winding has a spread. Although the broadening of the peak width is related to the deterioration of the iron core or the winding, it is necessary to determine for each transformer how much the peak width becomes the threshold of the deterioration diagnosis, because it depends on the design of each transformer.

この例では変圧器タンクの上部周壁の右側壁において、図16に示すように右側壁左右方向を1A、2A、…15Aのように分割区分し、右側壁上下方向を1A、1B、…1Gのように分割区分し、1つの振動センサを例えば3Cの位置に設置してその右側の4Cの位置をハンマーで打ち付けて振動を付与するインパクト試験を行った。
また、振動センサを13Fの位置に設置して13Eの位置をハンマーで打ち付ける試験としても良い。なお、振動センサを取り付ける位置とハンマーを打ち付ける位置は変圧器タンクの振動を良好に拾うことができる位置であれば、任意の位置で良く、図16に示す位置には限らない。
In this example, in the right side wall of the upper peripheral wall of the transformer tank, as shown in FIG. 16, the right side wall right and left direction is divided as 1A, 2A,... 15A, and the right side wall vertical direction is 1A, 1B,. As shown in the figure, an impact test was conducted in which the vibration sensor was placed at a position of, for example, 3C, and the position of 4C on the right side was hit with a hammer to apply vibration.
Alternatively, a vibration sensor may be installed at the position of 13F and a test of striking the position of 13E with a hammer may be performed. The position where the vibration sensor is attached and the position where the hammer is hit may be any position as long as the vibration of the transformer tank can be picked up well, and is not limited to the position shown in FIG.

振動センサを3Cの位置に設置したまま稼働中の変圧器タンクの振動を計測し、その測定結果をフーリエ変換した結果の波形を図17の下側に波形(実稼働時の波形)で示す。
前記振動センサを3Cの位置に設置したまま変圧器稼働中に4Cの位置をハンマーで打ち付けるインパクト試験を行った場合に得られた振動測定結果をフーリエ変換した結果の波形を図17の上側に波形(加振時の波形)で示す。
The vibration of the transformer tank in operation is measured while the vibration sensor is installed at the 3C position, and the result of Fourier transform of the measurement result is shown in the lower side of FIG. 17 as a waveform (waveform at the time of operation).
The waveform of the result of the Fourier transform of the vibration measurement result obtained when the impact test was performed by striking the position of 4C with a hammer while the transformer was in operation while the vibration sensor was installed at the position of 3C It shows by (waveform at the time of excitation).

実稼働時の振動測定結果を示す波形には、60Hzの整数倍(120、180、240、300、360、420Hz)に大きなピークが見られる他に、強度の弱いピークも複数見られる。加振時の振動測定結果には60Hzの整数倍以外にも垂直な点線(黒の鎖線)で示す周波数位置(142、217、334Hz等)にいくつかのピークが見られる。実稼働時のピークのうち、加振時のピークが重なるものは、タンク壁面の固有振動成分であると考えられる。ただし、加振時のピークがタンク壁面の固有振動成分であるかは、同時に測定する位相成分の変化を確認し、更にセンサの設置位置や打点を変更して測定を繰り返し、検討の上、判断することが好ましい。   In the waveform showing the vibration measurement result during operation, a large peak is seen at an integer multiple of 60 Hz (120, 180, 240, 300, 360, 420 Hz), and a plurality of weak peaks are also seen. In the vibration measurement result at the time of excitation, some peaks are seen at frequency positions (142, 217, 334 Hz, etc.) indicated by vertical dotted lines (black dashed lines) other than integral multiples of 60 Hz. Of the peaks at the time of actual operation, those having overlapping peaks at the time of excitation are considered to be natural vibration components of the tank wall surface. However, whether the peak at the time of vibration is the natural vibration component of the tank wall is confirmed by checking the change of the phase component to be measured at the same time, and changing the installation position of the sensor and the hitting point. It is preferable to do.

巻線振動によるピークは先に段落0079で記載したように、負荷率を変えて強度が変化するピークを同定することが好ましい。変圧器振動のうち、タンクの振動と巻線振動を上述の如く分離すると、残りは鉄心振動と考えられる。
ただし、稼働中の変圧器周辺は、電磁ノイズが大きい環境である。振動センサ、増幅器、解析器、およびそれらを接続するケーブルや測定機器駆動電源に電磁ノイズが影響することが考えられる。また、変圧器設置箇所の建物や地面が揺れている可能性もある。それらのノイズの影響を除去または軽減する工夫を行うことも、診断の精度を向上させる上で重要である。
It is preferable to change the load factor to identify a peak whose intensity changes, as described in paragraph 0079 above. Of the transformer vibrations, when the tank vibrations and the winding vibrations are separated as described above, the remainder is considered as iron core vibrations.
However, the area around the operating transformer is an environment where electromagnetic noise is large. It is conceivable that electromagnetic noise may affect a vibration sensor, an amplifier, an analyzer, a cable connecting them, and a driving power source of a measuring instrument. There is also a possibility that the building at the transformer installation site and the ground are shaking. It is also important to improve the accuracy of diagnosis by devising to eliminate or reduce the influence of the noise.

電磁ノイズに影響を受けやすい機器を金属箔で覆い、機器缶体を充分に接地し、機器をバッテリー駆動方式とするなどの工夫を併用して上述の試験を行うことが望ましい。
また、試験を行う場所の建物や地面の振動を同時に測定したり、変圧器を定期修理することが可能な場合は、その機会に予め背景ノイズを測定して確認しておき、変圧器の振動から差し引くなどの処理を行うことが望ましい。
It is desirable to conduct the above-described test using a device such as a device susceptible to electromagnetic noise covered with metal foil, a sufficient grounding of the device can, and a device driven by a battery.
Also, if it is possible to simultaneously measure the vibration of the building or ground where the test is to be performed or if it is possible to regularly repair the transformer, measure and confirm background noise in advance at that opportunity to check the vibration of the transformer. It is desirable to perform processing such as subtraction from.

A…診断装置、1…変圧器、2…タンク、3…コイル体、5…鉄心、8…締め付け金具、9…外側コイル(1次コイル)、10…内側コイル(2次コイル)、11…外巻線(1次巻線)、12…絶縁スペーサー、16…内巻線(2次巻線)、22…振動検出器(振動センサ)、23…電圧計、24、25…増幅器、26…解析器、27…演算装置。   A: Diagnostic device 1: Transformer 2: Tank 3: coil body 5: iron core 8: fastening bracket 9: outer coil (primary coil) 10: inner coil (secondary coil) 11: Outer winding (primary winding), 12 ... insulation spacer, 16 ... inner winding (secondary winding), 22 ... vibration detector (vibration sensor), 23 ... voltmeter, 24, 25 ... amplifier, 26 ... Analyzer, 27 ... arithmetic unit.

Claims (6)

鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器であって、
稼働状態の変圧器振動について、低周波数領域から可聴音領域(1Hz〜20kHz) に検出感度を有する振動検出器を用い、電子回路またはソフトウエアを用いた信号処理に よる手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置において前記振動検出器から求めた出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークと、
前記振動検出器により前記所定の負荷率で稼働中の変圧器のタンク表面の前記節の位置から外れた位置で測定した出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークとを比較し、
測定位置を前記節の位置から変えることにより前記ピークが示す振動強度が変化した周波数の振動は前記タンクの振動と把握し、残りの振動を鉄心振動あるいは巻線振動と把握するとともに、
前記残りの鉄心振動あるいは巻線振動について、前記振動検出器の測定位置を前記タンク表面の振動の節の位置に設定し、負荷率を前記所定の負荷率から変更して求めた前記フーリエ変換結果のピーク比較から、振動強度が変化しない周波数の振動を鉄心振動と判断し、振動強度が弱くなった周波数の振動を巻線振動と判断し、
前記鉄心振動と巻線振動の一方または両方を健全な変圧器に対して前記方法と同等方法で求めた鉄心振動と巻線振動の一方または両方と比較して変化がある場合に内部異常および劣化を生じたと判断することを特徴とする変圧器内部異常および劣化の診断方法。
A transformer comprising an iron core, a coil body, windings constituting the coil body, and a tank containing the coils,
With regard to transformer vibration in the operating state, using the vibration detector having detection sensitivity in the low frequency region to the audible sound region (1 Hz to 20 kHz), using the means by signal processing using an electronic circuit or software The smallest area of the tank surface vibration of the operating transformer due to the electromagnetic force generated by the energizing current applied to the transformer at a predetermined load factor as the node of the vibration, said vibration detector at the position of said node And the peak of the result drawn on a graph in which the result is set to the vibration intensity on the vertical axis and the frequency on the horizontal axis.
The output waveform measured at a position deviated from the position of the node on the tank surface of the operating transformer at the predetermined load factor by the vibration detector is subjected to Fourier transform, and the result is the vertical axis vibration intensity and horizontal axis frequency Compare with the peak of the result drawn on the set graph,
By changing the measurement position from the position of the node, the vibration of the frequency at which the vibration intensity indicated by the peak changes is grasped as the vibration of the tank, and the remaining vibration is grasped as iron core vibration or winding vibration.
Regarding the remaining iron core vibration or winding vibration, the measurement position of the vibration detector is set to the position of the node of vibration of the tank surface, and the load factor is obtained by changing the load factor from the predetermined load factor. Based on the peak comparison of the above, it is judged that the vibration of the frequency at which the vibration intensity does not change is the core vibration, and the vibration of the frequency at which the vibration intensity has become weak is the winding vibration,
Internal anomalies and deterioration when there is a change in either or both of the core vibration and the winding vibration as compared to one or both of the iron core vibration and the winding vibration obtained by the same method as the above method for a sound transformer A method of diagnosing internal abnormality and deterioration of a transformer characterized by determining that
請求項1で求めた鉄心振動と巻線振動の一方または両方が経時的に変化することを捕捉して稼働中の変圧器の状態を判断することを特徴とする請求項1に記載の変圧器内部異常および劣化の診断方法。 The transformer according to claim 1, wherein one or both of the iron core vibration and the winding vibration determined in claim 1 are captured by changing over time to determine the state of the transformer in operation . How to diagnose internal anomalies and deterioration. 鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器であって、稼働状態の変圧器振動について、振動検出器を用い、電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置における前記振動検出器の出力波形を測定し、この出力波形から変圧器電源周波数の整数倍波を抽出し、該整数倍波の振幅を規格化した波形と、前記変圧器の電源電流波形から前記整数倍波と同等周波数の振幅を規格化した波形を比較して両波形の位相差を求め、健全な変圧器で測定しておいた位相差と変化がある場合に内部異常および劣化を生じたと判断することを特徴とする変圧器内部異常および劣化の診断方法。 A transformer having an iron core, a coil body, windings constituting the coil body, and a tank containing the coils, wherein an electronic circuit or software is used for a transformer vibration in an operating state using a vibration detector. The smallest area of the tank surface vibration of the operating transformer due to the electromagnetic force generated by the energizing current applied to the operating transformer at a predetermined load factor using means by signal processing Measuring the output waveform of the vibration detector at the position of the node, extracting an integer multiple of the transformer power supply frequency from the output waveform, and standardizing the amplitude of the integer multiple, and a waveform of the transformer Determine the phase difference between both waveforms by comparing the normalized waveform of the same frequency with the integer multiple wave from the power supply current waveform, and if there is a phase difference and change measured with a sound transformer, an internal error And degradation Transformer internal fault and diagnostic methods deterioration is characterized by judging that. 前記位相差が経時的に変化することを捕捉して稼働中の変圧器の状態を判断することを特徴とする請求項3に記載の変圧器内部異常および劣化の診断方法。 The method according to claim 3, wherein the state of the operating transformer is determined by capturing changes in the phase difference with time . 鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器に対し適用される変圧器の内部異常および劣化の診断装置であって、
稼働中の変圧器に装着されて該変圧器が発生する低周波数領域から可聴音領域(1Hz 〜20kHz)に至る振動に対し検出感度を有する振動検出器と、該振動検出器からの検 出信号を受けて稼働中の変圧器に対する通電電流による加振力に伴う機械的振動を求める解析器と、前記解析器から得られたデータを演算する演算手段とを備え、
前記演算手段が、
電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置において前記振動検出器から求めた出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークと、
前記所定の負荷率で稼働中の変圧器のタンク表面の振動の節の位置から外れた位置で測定した出力波形をフーリエ変換してその結果を縦軸振動強度、横軸周波数に設定したグラフに描いた結果のピークとを比較し、
測定位置を前記節の位置とそれより外れた位置に変えることにより前記ピークが示す振動強度が変化した周波数の振動は前記タンクの振動と把握し、残りの振動を鉄心振動あるいは巻線振動と把握し、
前記残りの鉄心振動あるいは巻線振動について、前記振動検出器の測定位置を前記タンク表面の振動の節の位置に設定し、負荷率を前記所定の負荷率から変更して求めた前記フーリエ変換結果のピーク比較から、振動強度が変化しない振動を鉄心振動と判断し、振動強度が弱くなった振動を巻線振動と判断するとともに、
前記鉄心振動と巻線振動の一方または両方について、健全な変圧器に対して前記同等方法で求めた鉄心振動と巻線振動の一方または両方と比較して変化がある場合に内部異常および劣化を生じたと前記演算手段が判断する機能を有したことを特徴とする変圧器の内部異常および劣化の診断装置。
It is a diagnostic device for internal abnormality and deterioration of a transformer applied to a transformer having an iron core, a coil body, a winding constituting the coil body, and a tank accommodating these,
A vibration detector mounted on an operating transformer and having detection sensitivity to vibrations from the low frequency range generated by the transformer to an audible sound range (1 Hz to 20 kHz), and a detection signal from the vibration detector And an analyzer for obtaining mechanical vibration associated with the excitation force due to the energizing current to the transformer in operation, and an operation means for operating data obtained from the analyzer.
The computing means
Tank surface vibration of the operating transformer due to the electromagnetic force generated by the energizing current applied to the operating transformer at a predetermined load factor by means of signal processing using electronic circuits or software The output waveform obtained from the vibration detector at the position of the node with the smallest region of vibration as the node of the vibration Fourier-transformed, and the result is the peak of the result drawn in the graph set to the vertical axis vibration intensity and horizontal axis frequency ,
The output waveform measured at a position deviated from the position of the node of vibration on the tank surface of the transformer operating at the predetermined load factor is subjected to Fourier transform, and the result is set to the vertical axis vibration intensity and horizontal axis frequency. Compare with the peak of the drawn result,
By changing the measurement position to the position of the node and the position away from it, the vibration of the frequency at which the vibration intensity indicated by the peak changes is grasped as the vibration of the tank, and the remaining vibration is grasped as iron core vibration or winding vibration. And
Regarding the remaining iron core vibration or winding vibration, the measurement position of the vibration detector is set to the position of the node of vibration of the tank surface, and the load factor is obtained by changing the load factor from the predetermined load factor. Based on the peak comparison of the above, the vibration in which the vibration strength does not change is judged as iron core vibration, and the vibration in which the vibration strength is weakened is judged as winding vibration,
Internal anomalies and deterioration when there is a change in one or both of the core vibration and the winding vibration as compared to one or both of the iron core vibration and the winding vibration obtained by the equivalent method for a sound transformer. A diagnostic device for internal abnormality and deterioration of a transformer characterized by having a function of determining that the computing means has occurred .
鉄心とコイル体と該コイル体を構成する巻線とこれらを収容したタンクとを有する変圧器に対し適用される変圧器の内部異常および劣化の診断装置であって、
稼働中の変圧器に装着される振動検出器と、該振動検出器からの検出信号を受けて稼働中の変圧器に対する通電電流による加振力に伴う機械的振動を求める解析器と、前記解析器から得られたデータを演算する演算手段とを備え、
稼働状態の変圧器振動について、前記振動検出器を用い、電子回路またはソフトウエアを用いた信号処理による手段を用いて前記稼働状態の変圧器に所定の負荷率で付加されている通電電流により生じる電磁力に起因して稼働中の変圧器のタンク表面振動の最も小さい領域を振動の節として該節の位置における前記振動検出器の出力波形を測定し、この出力波形から変圧器電源周波数の整数倍波を抽出し、該整数倍波の振幅を規格化した波形と、前記変圧器の電源電流波形から前記整数倍波と同等周波数の振幅を規格化した波形を比較して両波形の位相差を求め、健全な変圧器で測定しておいた位相差と変化がある場合に内部異常および劣化を生じたと判断する機能を前記演算手段が有することを特徴とする変圧器の内部異常および劣化の診断装置。
It is a diagnostic device for internal abnormality and deterioration of a transformer applied to a transformer having an iron core, a coil body, a winding constituting the coil body, and a tank accommodating these,
A vibration detector attached to the operating transformer; an analyzer for obtaining mechanical vibration associated with the excitation force by the supplied current to the operating transformer in response to a detection signal from the vibration detector; Computing means for computing data obtained from the
With regard to the transformer vibration in the operating state, it is generated by the energizing current applied to the transformer in the operating state at a predetermined load factor using the vibration detector and means by signal processing using an electronic circuit or software. Measure the output waveform of the vibration detector at the position of the node with the smallest area of the tank surface vibration of the operating transformer due to the electromagnetic force, and from this output waveform, an integer of the transformer power frequency The phase difference between the two waveforms by comparing the waveform obtained by extracting the double wave and standardizing the amplitude of the integer multiple wave and the waveform obtained by normalizing the amplitude of the same frequency as the integer multiple wave from the power supply current waveform of the transformer Of the internal abnormality and deterioration of the transformer characterized in that the calculation means has a function of determining the internal abnormality and deterioration when there is a phase difference and change measured by the sound transformer. Medical examination Apparatus.
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