JP4118657B2 - Inspection method of electric power equipment by X-ray tomography inspection apparatus - Google Patents

Description

上記の特性からＸ線による投影を行なう際には、次のように考えられる。投影する対象物が薄かったり、質量の軽い対象物の場合、硬いＸ線を用いると減衰が少なく、対象物の厚さの差が出にくいコントラストのない撮影像となる。逆に、対象物が厚く、質量の重い物質の場合に軟X線を用いるとＸ線が透過しない。従って、Ｘ線による投影撮影を行なう場合、対象となる電力機器によってＸ線を発生させる管電圧を適切に選定する必要があることが見出され、電力機器である変圧器に使用されている絶縁樹脂の内部の状態、即ち、マイグレーション、クラックあるいはピンホール等を観察するには、軟Ｘ線領域を用いるのが効果的であることをつきとめた。
【００２５】
実験によると、Ｘ線を発生するＸ線管の管電流と管電圧に対するＸ線の強度との関係は、図４、図５に示す通りである。図４は、管電流が一定の場合のＸ線の強さ（I）と波長λとの関係を示す図、図５は、管電圧が一定の場合のＸ線の強さ（I）と波長λとの関係を示す図である。図４から明らかなように、管電圧を高くすると波長の短い硬いＸ線が多くなり（図４の斜線で示す部分）、対象物を透過した時に減衰が少なくコントラストの弱い透過画像になり、断層像としては不適である。従って、図５に示すように透過する対象物の種類により管電圧を設定したら管電流を調節してＸ線強度を変え、観察しやすい透過象の明るさを調節する必要があることを示している。従って、本発明者らは、この知見にしたがい、図３に示す制御装置４６によりＸ線管の管電圧および管電流を制御して、軟Ｘ線を発生する管電圧（図５に示す）に設定し、管電流を調整することによりＸ線強度を変え、観察しやすい断層像を得るように調節した。
【００２６】
次に、本発明に使用するＸ線断層像検査装置を図８を用いて説明する。８０は、Ｘ線８１を放射状に発生するＸ線管で、変圧器を構成する樹脂絶縁部材のマイグレーション、クラックあるいはピンホール等を観察するために軟Ｘ線を発生するＸ線管である。８２は、撮像ユニットで、詳細は、省略してあるが、図３に示す撮像面３５、蛍光倍増管４１、像回転プリズム４２および映像蓄積型の撮像装置４４から構成されている。８４は、ＸＹテーブルでこの上に高圧トランスのような重量物である検査対象物が載置され、対象物体をＸ方向、Ｙ方向に移動するのに用いられる。８４は、回転軸受け機構部でXYテーブル８３およびＸＹテーブルに載せられた検査対象物を回転軸８５（図２の回転軸２５に相当する）を中心にして回転させるものである。なお、駆動部分等は省略されて示してある。８６は、床のような土台であり、２００Kg以上もある高圧変圧器の非破壊検査のためのX線断層像検査装置を設置するに十分な強度を持つよう構成されている。８７は、土台８６に設けられた穴部で、撮像ユニット８２を配置するためのものである。８８は、床面を示す。特に、回転軸受け機構部８４でＸＹテーブル８３およびＸＹテーブルに載せられた電力機器のような重量物を回転軸８５を中心にして回転させるものであるため、極めて安定に回転させられるように回転軸受け機構部８４、ＸＹテーブル８３は、床面８８と共に、ほぼ水平に配置される。
【００２７】
而して、このＸ線断層像検査装置は、Ｘ線管８０を土台８６の上方に配置し、撮像ユニット８２は、土台８６に設けられた穴部８７内部に配置される。検査対象物を載置する試料台（ＸＹテーブル８３に相当する）は、この間に配置するが、本装置の場合、極めて重量の大きい変圧器等を載置するため、試料台が床面またはそれと同等な強度を持つ架台の上に設置するものとする。
【００２８】
また、試料台の回転軸受け機構８４は、床面に埋め込まれる構造とし、ＸＹテーブル８３は、床面上を移動する機構とする。これは、重量物を測定対象とするために工夫された構造であり、重量物の取付、重量を支える試料台、即ち、ＸＹテーブル８３、回転軸受け機構８４の制作を容易にするためである。撮像ユニット８２は、床面８８より下に配置され、撮像ユニット８２の像回転プリズム（図３の像回転プリズム４２に対応する）と試料台の回転軸８５を一致させるためのＸＹ方向の調整機構（図示せず）を持つ。
【００２９】
以上のように本発明に使用するＸ線断層像検査装置は、上述したように構成されているので、変圧器のような重量物の内部を非破壊で容易に検査できるＸ線断層像検査装置を実現することができ、従来非破壊で検査が不可能であった変圧器の内部の絶縁物の欠陥、例えば、マイグレーション、クラックあるいはピンホール等を容易に検査できるようになった。
【００３０】
次に、本発明の一実施例について説明する。本実施例においては、図８に示すＸ線断層像検査装置の試料台８３上に、例えば、検査すべき高圧変圧器を載置し、これにＸ線管８０から軟Ｘ線を照射した場合の検査方法について説明する。図６は、試料台８３上に載置された高圧変圧器の一部分、即ち、エポキシモールド変圧器の一部分の断面形状を示す。図６において、６１は、エポキシモールド変圧器の一部分の断面を示し、６２は、ブロック分割された銅線のコイルブロック、６３は、コイル部分を絶縁するためにモールドされたエポキシ樹脂層である。６４は、エポキシモールド変圧器の一部分６１の円形部分の拡大図を示すもので、６５は、銅線、６６は、エポキシ樹脂層である。このエポキシモールド変圧器をＸ線で透視したときの断層像写真を図１、７および９に示す。なお、本検査においては、図３で説明したと同様に、Ｘ線管８０の管電圧、管電流は、制御装置（図８では図示せず。図３の制御装置４６に対応する。）で調整される。
【００３１】
図７は、本発明により撮影したＸ線断層像写真で、Ｘ線管８０の管電圧７０KV、管電流８０μAで透視した場合のエポキシモールド変圧器の一部分の断層像写真である。図７において、７１は、銅線、７２は、エポキシ樹脂層で、2層に見える部分は、樹脂の種類が異なるためである。図９は、図７の一部拡大図である。この写真からも分かるように、銅線の周辺部に樹脂が流れたような形跡が認められる。これはモールド形成時に、エポキシ樹脂を注入したときにできたものと考えられる。図7および図９から分かるように、このエポキシモールド変圧器のＸ線断層像写真では、マイグレーション、クラックあるいはピンホール等の内部欠陥は見当たらない。従って、劣化や欠陥のないエポキシモールド変圧器であることがわかる。
【００３２】
而して、図１は、Ｘ線管８０の管電圧７０KV、管電流８０μAで透視した場合のエポキシモールド変圧器の一部分の断層像写真の拡大図である。図において、１は、銅（Ｃｕ）からなる導電配線材であり、２は、エポキシ樹脂であり、導電材料１間を絶縁している。３は、マイグレーションで、高温多湿の環境下で銅が菌糸状に成長し、絶縁樹脂の中を伸びている状態が観察される。４は、絶縁樹脂を形成する際に生じた樹脂の流れを示すものである。５は、クラックで、経年変化により、樹脂の乾燥、膨張収縮の繰り返しで、樹脂の流れにそって発生したものと考えられる。図１から明らかなように、高圧変圧器の内部のエポキシ樹脂のマイグレーションやクラックが非破壊で、検査が可能であることがわかる。従って、このＸ線断層像検査方法を利用すれば、電力機器の劣化状態を定期的に検査し、電力機器の保守、寿命予測および事故の予防をすることが可能である。
【００３３】
以下検査方法の一実施例について図１０を用いて説明する。図１０は、電力機器等の製品を製造工場等から出荷し、変電所等の現地に据え付け、その後、保守点検のために定期的に検査する方法のフローを示している。図１０の左の欄は、出荷工場でのステップ、中央のデータサーバーの欄は、例えば、電力会社、保守点検サービス会社あるいは製造メーカ等の中にある管理部門のコンピュータ室の処理ステップ、右の欄は、変電所等の現地での処理ステップを示している。
【００３４】
まず、検査方法のフローが開始１００から始まり、初期データ作成１０１（ステップ１）に進む。このステップ１は、工場出荷時の製品検査時に各製品について前もって定められた保守点検項目に従って初期データの作成が行なわれる。
ステップ１：初期データの作成。初期データを作成し、データサーバー１０２に記録し、保管される。この初期データは、電力機器、例えば、高圧変圧器の出荷時の欠陥のないデータである。図８に示すＸ線断層像検査装置を用いて、高圧変圧器の出荷時に撮影する。撮影条件としては、検査画像、撮影日、撮影条件等、即ち、管電圧、管電流、積分回数、濃淡調整データ、撮影位置（ＸＹ座標、角度等）等、月あるいは年単位で同じ場所を撮影し、再現性よく比較することができるように定めることが必要である。このためには、図３の制御部４６内の処理部および記録部が使用される。なお、撮影個所は、過去の経験から劣化が進むと考えられる場所に限定することが望ましい。その方が撮影時間も短く、またデータサーバー１０２の記録容量も少なくてすむ。このようにして撮影されたＸ線断層像は、撮影条件と共に、例えば、表２のようなテーブルにしてデータサーバー１０２に保管される。
【００３５】
【表２】

表２のテーブルについて説明する。撮影個所A、B、・・・Nは、例えば、図６に示すエポキシモールド変圧器のＸ線断層像撮影場所を示す。出荷時検査データは、製品を出荷する時点で、それぞれの撮影場所のＸ線断層像を図８のＸ線断層像検査装置で撮影した時のＸ線断層像写真である。例えば、写真A-1は、図９に示すＸ線断層像写真である。写真B-1、・・・・写真N-1も同様に、エポキシモールド変圧器の他の部位のＸ線断層像写真である。また、同時に、撮影条件のエリアには、撮影条件として、前述したような管電圧、管電流、積分回数、濃淡調整データ、撮影位置等を記録する。例えば、出荷時の写真A-1が撮影された撮影条件、即ち、管電圧70KV、管電流80μA等が記録される。
【００３６】
検査終了した製品は、変電所等の現地に運ばれ据付け（１０３）られ、運用（１０４）が開始される。所定期間経過後に、定期検査データ作成１０５（ステップ２）が行われる。なお、この定期検査までに破損したものについては、破損１０６、検査データ修正１０７のステップにより、データサーバー１０２のデータが修正され、また、破損した電力機器は、破棄され、新しい電力機器と交換される。
【００３７】
ステップ２：第1回検査データの収集。これは、運用中の定期検査であり、第1回検査データが、収集される。第1回検査データとしては、例えば、出荷5年後に同一のエポキシモールド変圧器をそれぞれの部位で、同一の撮影条件で撮影したＸ線断層像写真であり、第1回の検査データがデータサーバー１０２のテーブル表２に記録される。写真A-2は、エポキシモールド変圧器の撮影場所Aで、写真A-1と同じ条件で撮影したＸ線断層像写真である。例えば、図１に示すＸ線断層像写真がこれに相当する。表２に示す第２回検査データは、更に、３〜５年後の検査が必要な場合に、その時点の検査データが蓄積される場所である。なお、出荷時のＸ線断層像写真の撮像位置と第1回の検査データのＸ線断層像写真とは、撮像場所をほとんど同じにする必要があり、撮像条件を同じにしたとしても位置的に若干ずれる場合がある。従って、より精度を上げるためには、出荷時のＸ線断層像写真の画像と第1回の検査データのＸ線断層像写真の画像とを比較し、位置的に合致するかどうかを判定して、第1回の検査データのＸ線断層像写真を撮像するのが望ましい。
【００３８】
次に、現品データとの比較１０８（ステップ３およびステップ４）では、同一製品の初期データと第１回検査データとが比較され、劣化の状況が判定される。
【００３９】
ステップ３：画像比較。Ｘ線断層像写真の比較が行なわれる。製品の変化の判定は、出荷時に撮影した出荷時検査データの写真と第1回検査データの写真の比較により行なわれる。例えば、写真A-1（図９に示す）と写真A-2（図１に示す）との比較で行なわれる。比較方法には、種々の方法があるが、画像処理として良く知られた方法は、画像を画素（ピクセル）単位に分割し、画素単位に、輝度レベルで比較する方法、また、画像を複数のエリアに分割し、エリア毎に輝度レベルを比較する方法、あるいは画像のヒストグラムを算出し、ヒストグラムの形状を比較する方法が用いられる。あるいは検査制度を高めるために、これらを組み合わせて用いられる。比較の結果、写真A-1と写真A-2との間に、違いが生じた場合には、エポキシモールド変圧器を構成する物質に変化があったことが検出される。
【００４０】
ステップ４：劣化の判定：上記画像比較から、例えば、輝度のレベル、ヒストグラムの形状が３０％以上変化している場合は、劣化があったとして高圧変圧器を交換する等の対策をする。なお、どの程度の変化があれば、電力機器の交換が必要か否かの判定は、種々の実験データ、出荷時のデータおよび数年後の製品の検査データを蓄積し、これらを分析して、判断する必要があることは勿論であるが、本発明者らの検査データによれば、マイグレーション、クラック、ピンホールは次のようにして検出される。
【００４１】
マイグレーションの検出：写真A-1と写真A-2を比較すると明らかなように、マイグレーション３は、樹脂中を成長するひげ状のもので、線材と同じ銅部材であり、樹脂部分より暗い画像となる。従って、比較画像の輝度レベルにより、判定できる。また、劣化の程度の判断としては、マイグレーション３の長さが導電配線部材１間の距離の５０％を超える長さに成長すれば、高圧変圧器は、劣化し、交換時期である。
【００４２】
クラックの検出：写真A-1と写真A-2を比較するが、明るさの補正が必要である。明るさの補正は、ヒストグラムの一致を取る際に、最も一致が取れた時の明るさ方向のオフセットを利用する。そして検出されるデータの内、一定面積以上のクラックがあれば交換する。あるいは、クラックは、樹脂が割れてできたもので、空気層と考えられ、樹脂部分の輝度レベルより明るい輝度レベルとなる。従って、差画像の輝度レベルを検出することで、クラックの判断ができるので、一定面積以上のクラックがあれば劣化と判断できる。
【００４３】
ピンホールの検出：クラックの検出と同様であるが、形状が円形のものをピンホールと判定する。
【００４４】
以上のようにして判定された結果により、電力機器の継続運用の可否判断１１０が行なわれ、まだ十分に運用に耐えるものについては、引き続き運用され、劣化しているものについては、破棄１１１に進み、新しいものと交換される。
【００４５】
なお、図１０においては、更に、現品外のデータとの比較１０９（ステップ５およびステップ６）が設けられている。これは、上述した現品データとの比較１０８とは別に、同種の別の電力機器、本例の場合は、前に検査した別のエポキシモールド変圧器の劣化データをデータサーバー１０２に保存しておき、前に検査した別のエポキシモールド変圧器の劣化データであるＸ線断層像写真と上記第1回の検査データのＸ線断層像写真とを比較し、劣化を判定する。勿論、現品外のデータとの比較１０９（ステップ５およびステップ６）は、必ずしも必要ではないが、劣化の判定の精度を高めるためには、必要なステップである。
【００４６】
ステップ５：画像比較。ここでは、前に検査した別のエポキシモールド変圧器の劣化データであるＸ線断層像写真と上記第1回の検査データのＸ線断層像写真とを、例えば目視で比較し、両者に変化があるか否かを判断する。
【００４７】
ステップ６：劣化の判定。ここではステップ５の画像比較から劣化の状況が把握される。即ち、過去の劣化の状況を示す写真と第1回の検査データのＸ線断層像写真とを目視で比較すれば、劣化の状況が一目で把握でき、高圧変圧器の劣化の判断が極めて容易となる。
【００４８】
以上のようにして、マイグレーション、クラック、ピンホールの検出が、非破壊により行なえる。なお、差画像により検出されるものの内、樹脂の流れと思われるものも検出されるが、これは、目視にて判断される。勿論、画像が完全に一致していれば検出はされないし、また、適宜検出レベルに閾値を設けることにより除去できることは言うまでもない。
【００４９】
以上説明したように、本発明のＸ線断層像検査方法は、非破壊で電力機器のような重量物の検査を行なうことができることが分かる。また、検査結果からマイグレーション、クラック、ピンホールの成長過程等を検査できるため、電力機器等の劣化の程度を判定することが可能となった。
【００５０】
なお、Ｘ線断層像検査装置の制御部（図示せず）は、撮像ユニット８２で撮像されたＸ線透過画像を蓄積装置に蓄積する機能の他に、必要に応じて、電子データとして解析し、高圧変電機器の材料劣化を解析する機能や、解析結果を保存あるいは管理する機能も有していることは言うまでもない。また、Ｘ線透過画像の電子データは、公衆回線（例えば、ＡＤＳＬ）により電力会社等の基地局に送ることも可能である。
【００５１】
以上、本発明について詳細に説明したが、本発明は、ここに記載されたＸ線断層像検査方法に限定されるものではなく、上記以外に、非破壊により電力機器等の内部を検査する装置や方法に広く適応することが出来ることは言うまでも無い。
【００５２】
【発明の効果】
以上説明したように、従来、電力機器等の高電圧機器、重量物の内部の劣化を直接検査する方法がなく、また、電力機器の劣化の原因が絶縁樹脂のマイグレーション、クラックあるいはピンホール等によるものと考えられていたが、これを直接検査する方法が今まで実現されていなかった。本発明は、電力機器の劣化を非破壊で直接観察することのできる電力機器用Ｘ線断層像検査方法を実現し、定期的に電力機器の検査が可能となり、使用電力機器の交換コストも安く、しかも大事故を未然に防ぐことができ、また、電力機器の寿命予測についても、種々の実験データ、出荷時のデータおよび数年後の製品の検査データを蓄積し、これらを分析して、判断することにより可能となる等極めて有用なＸ線断層像検査方法を実現した。
【図面の簡単な説明】
【図１】本発明の一実施例のＸ線断層像を示す図である。
【図２】本発明の原理を説明するための図である。
【図３】本発明に使用するＸ線断層像検査装置の原理的構成を示す図である。
【図４】本発明に使用するＸ線断層像検査装置の動作を説明するための管電流一定の場合のＸ線強度を示す図である。
【図５】本発明に使用するＸ線断層像検査装置の動作を説明するための管電圧一定の場合のＸ線強度を示す図である。
【図６】本発明の検査に使用された高圧トランスの一部の断面図を示す図である。
【図７】本発明の検査方法による断層像の一例を示す図である。
【図８】本発明に使用するＸ線断層像検査装置の一実を示す図である。
【図９】本発明の検査方法による断層像の一例を示す図である。
【図１０】本発明の一実施例を示す図である。
【符号の説明】
１：導電配線材、２：絶縁樹脂、３：マイグレーション、４：樹脂の流れ、５：クラック、３１、８０：Ｘ線管、３２：Ｘ線発生点、３４：光軸、３５：撮像面、３６：ＸＹ移動機構、３７：回転テーブル、３８、８１：回転テーブルの回転軸、３９：対象物、４０：断層面、４１：蛍光倍増管、４２：像回転プリズム、４３：像回転プリズムの回転軸、４４：映像蓄積型の撮像装置、４６：制御装置、４７：表示装置、８６：土台、８７：土台にあけられた穴部、８８：床面。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for inspecting electric power equipment using an X-ray tomography inspection apparatus, and in particular, inspects high-voltage equipment such as electric power equipment and heavy electric power equipment in a non-destructive manner, maintenance of electric power equipment etc. and prevention of accidents. The present invention relates to an inspection method for electric power equipment.
[0002]
[Prior art]
Electricity supplied to each household, public utility, factory, etc. is generated at a remote power plant, boosted, sent to a substation near the city, where it is stepped down, and a pole transformer The voltage is stepped down and distributed. Such power distribution equipment is highly public, and it goes without saying that if power equipment used in such power distribution equipment, such as transformers, insulators, and lightning rod parts, breaks down, the damage at the time of failure is extremely large. Yes. Therefore, in order to prevent failure, the life of the power equipment used is set in advance in anticipation of safety, and is currently being replaced regardless of whether or not the power equipment has actually deteriorated. is there. For example, in the case of a high-voltage transformer, the manufacturer's replacement life was specified as 5 years, and was forced to replace in 5 years. In addition, even if the lifetime of the power equipment used is set in advance in anticipation of safety, the degradation of these power equipment may progress earlier than expected, and failure may occur before the set lifetime. It also caused a wide range of power outages.
[0003]
The cause of such deterioration of electric power equipment has been clarified day and night by manufacturers and electric power companies, but has not yet been clarified. In order to investigate the cause, it is conceivable to directly inspect the power equipment used. For example, it is used at a high voltage of 3,000 V, and the total weight is over 200 kg. There is also a problem that it cannot be done. Therefore, conventionally, there is no method other than replacement within a period designated by the manufacturer, and the replacement cost of the power equipment used has been high.
[0004]
An X-ray tomographic imaging apparatus for inspecting defects such as semiconductors has been conventionally known (see, for example, Patent Document 1). However, a conventional X-ray tomography apparatus for inspecting defects such as semiconductors is an apparatus for inspecting defects of a very small internal structure and a small internal structure, and is a large and heavy power device. There was no device for inspecting such objects.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-31735 (page 3-5, FIG. 1-5)
[0006]
[Problems to be solved by the invention]
According to the study by the present inventors, it has been found that the cause of such deterioration of the power equipment is caused by the deterioration of the material itself constituting the power equipment. As a cause of deterioration of the material itself, it is predicted that the copper member of the winding wire constituting the transformer grows in a mycelium shape in the insulating resin, cracks generated in the insulating resin, and pinholes. However, it is difficult to directly observe the migration, cracks or pinholes of the power equipment used, to grasp the growth process and progress, and to predict the life.
[0007]
The objective of this invention is providing the inspection method of the electric power apparatus which can observe deterioration of an electric power apparatus directly by X-ray, and can test | inspect a deterioration state.
[0008]
Another object of the present invention is to provide a method of inspecting power equipment for non-destructive observation of deterioration of the power equipment and maintenance of the power equipment and prevention of accidents.
[0009]
Another object of the present invention is to provide an inspection method for electric power equipment that enables maintenance and inspection of the electric power equipment.
[0010]
Still another object of the present invention is to provide a power device inspection method capable of predicting the life of a power device.
[0011]
[Means for Solving the Problems]
The inspection method of the electric power equipment by the X-ray tomography inspection apparatus of the present invention rotates around the vertical axis and mounts the electric power equipment, generates X-rays, and the optical axis of the X-rays is the vertical axis. An X-ray generator disposed so as to be inclined with respect to an axis; means for converting an X-ray image transmitted through a power device mounted on the mounting table into an optical image; and synchronization with rotation of the mounting table. X-ray tomographic examination for electric power equipment comprising means for rotating the optical image, means for converting the rotated optical image into an electric signal, and a controller for processing the electric signal to obtain an X-ray tomographic image In the apparatus, X-ray tomographic image data of a predetermined part at the initial stage of manufacture of the power device and imaging conditions at that time are accumulated, and X-rays obtained by photographing the predetermined part of the power device under the same conditions as the imaging condition after a predetermined time has elapsed. Accumulated tomographic image data X-ray tomographic image data of the part and X-ray tomographic image data of the predetermined part after the predetermined time have passed are compared, and the result of the comparison is used to inspect for deterioration of the electric power equipment based on a predetermined determination criterion. This is realized by a method for inspecting electric power equipment using a line tomogram inspection apparatus.
[0012]
Further, in the inspection method for electric power equipment by the X-ray tomography inspection apparatus of the present invention, the predetermined determination criterion is based on the X-ray tomography inspection apparatus which is at least one of the determination criterion of migration, crack or pinhole. This is realized by an inspection method for electric power equipment.
[0013]
Further, in the inspection method for electric power equipment by the X-ray tomography inspection apparatus of the present invention, X-ray tomographic image data obtained by imaging a predetermined part of the electric power equipment under the same conditions as the imaging conditions is recorded at least twice. This is achieved by a method for inspecting a power device by an X-ray tomogram inspection apparatus that predicts the state of deterioration and the life of the power device from the comparison result of the X-ray tomogram data of the device.
[0014]
In the method for inspecting electric power equipment by the X-ray tomography inspection apparatus of the present invention, X-ray tomographic image data obtained by imaging a predetermined part of another electric power equipment of the same type as the electric power equipment under the same conditions as the imaging conditions is further provided. Recording, comparing the X-ray tomographic image data of a predetermined part of the another power device with the X-ray tomographic data of the predetermined part of the power device, and inspecting the state of deterioration of the power device. This is achieved by a method for inspecting electric power equipment by an X-ray tomogram inspection apparatus.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Before describing the present invention, the principle of laminography X-ray tomography used in the present invention will be described with reference to FIG. In FIG. 2, X-rays 22 are generated radially from a fixed X-ray source 21. The object 23 to be imaged rotates around a rotation axis 25 inclined with respect to the optical axis 24. The detector 26 rotates in synchronization with the object 23 around a rotation axis 27 parallel to the rotation axis 25. A projected image of a plane (hereinafter referred to as a focal plane) 28 that includes the intersection of the optical axis 24 and the rotation axis 25 and is perpendicular to the rotation axis 25 is detected as a stationary image by the detector 26. Since the other projected images are detected as rotating images, they are detected by the detector 26 in a blurred manner. For this reason, the captured image of the structure other than the focal plane 28, that is, the structure separated from the focal plane 28 is blurred and only the X-ray tomographic image on the focal plane 28 is clearly detected.
[0016]
Next, the principle configuration of the X-ray tomography apparatus used in the present invention using the principle of the X-ray tomography will be described with reference to FIG. In FIG. 3, 31 is an X-ray tube that generates X-rays, 32 is an X-ray generation point that generates X-rays, and 33 is an X-ray generated from the X-ray tube 31 and is irradiated in a conical shape. This is a simulation. Reference numeral 34 denotes an optical axis of an X-ray 33 that connects the center position of the imaging surface 35 and the X-ray generation point 32. Reference numeral 36 denotes a moving mechanism in the X-axis and Y-axis directions, which is an XY table for positioning a portion of an object (sample) to be photographed on the X-ray optical axis 34. Reference numeral 37 denotes a sample table, which is a rotary table that rotates about a rotary shaft 38 as a rotary shaft. The rotation shaft 38 corresponds to the rotation shaft 25 shown in FIG. The XY table 36 and the rotary table 37 are provided with a moving mechanism (not shown) in a direction perpendicular to the rotating surface for changing the tomographic plane and a moving mechanism (not shown) for performing geometric enlargement. Yes.
[0017]
Reference numeral 39 denotes an object to be photographed, which is fixed on the rotary table 37. Reference numeral 40 denotes a tomographic plane of the object 39 to be imaged, which is a plane parallel to the imaging plane 35 including the intersection of the X-ray optical axis 34 and the rotary axis 38 of the rotary table 37. The tomographic plane 40 can be moved to the site where the tomographic image of the object 39 is desired to be taken by the above-described vertical direction moving mechanism, and the object in the X and Y directions of the object can be obtained by the XY table 36. The tomographic image of the object can be moved to a desired site.
[0018]
Reference numeral 41 denotes a fluorescence multiplier tube. The imaging surface 35 is formed of an X-ray fluorescent material, and has a function of converting the intensity of X-ray energy into visible light. However, the visible light converted by the imaging surface 35 is weak, and thus doubles the fluorescence. The tube 41 has a function of amplifying the light intensity. In addition, when the imaging surface 35 is intended for a large object such as a power device, for example, a high-voltage transformer, the imaging surface 35 is desirably as large as possible in the visual field range. At present, a fluorescent screen with a size of 300 mmφ is commercially available and can be used. Note that the fluorescent multiplier 41 including the imaging surface 35 having sensitivity to X-rays is called an X-ray image intensifier.
[0019]
Reference numeral 42 denotes an image rotation prism, and the image rotation prism 42 rotates about the rotation axis 43 of the image rotation prism. The rotation shaft 43 corresponds to the rotation shaft 27 shown in FIG. 2, but the rotation speed and direction rotate in the reverse direction at a constant speed with respect to the rotation shaft 38. Therefore, the image rotation prism 42 rotates in the reverse direction at a constant speed with respect to the rotation table 37 that is a sample stage, and the rotation shaft 38 of the rotation table 37 and the rotation shaft 43 of the image rotation prism 42 are kept parallel. It is configured.
[0020]
Reference numeral 44 denotes a video storage-type imaging device, for example, a television camera. A tomographic image of the object 39 projected on the imaging surface 35 is amplified by the fluorescence multiplier 41, and the image is rotated by the image rotation prism 42. The tomographic image is taken by a TV camera. A tomographic image taken by the television camera 44 is converted into a video signal and input to a control device 46, for example, a control computer via a transmission path 45. In the control device 46, a tomographic image taken by the television camera 44 is recorded as a video signal in a recording device (not shown) inside the control device 46, and a tomographic image of the object is displayed on the display device 47 if necessary. Is done. In addition, the control device 46 moves in a direction perpendicular to the XY table 36, the rotation table 37, and the rotation plane for changing the tomographic plane in order to position the target 39 and adjust the part of the target to be imaged. It has a function of controlling a mechanism (not shown), a moving mechanism (not shown) that performs geometric enlargement, and the like. Further, the control device 46 is configured so that the tube voltage and the tube current can be adjusted in order to control the intensity and wavelength of the X-ray irradiated from the X-ray tube 31 to the object 39 as will be described later.
[0021]
Thus, the reason why a tomographic image of an object can be taken in the configuration shown in FIG. 3 will be described below. As described with reference to FIG. 2, X-rays 33 are radiated radially from the X-ray generation point 32 of the X-ray tube 31 to irradiate the object 39 to be imaged. A tomographic image of the tomographic plane 40 (focal plane) of the object 39 including the intersection of the optical axis 34 of the X-ray 33 and the rotational axis 38 of the rotary table 37 is projected onto the imaging plane 35. The tomographic image projected on the imaging surface 35 is amplified by the fluorescence multiplier 41, and the tomographic image is reversely rotated by the image rotating prism 42 that rotates in the direction opposite to the rotation table 37 at a constant speed, and is incident on the television camera 44. Here, since the optical axis 34 of the X-ray 33 is inclined with respect to the rotation axis 38, the projection image of the tomographic plane 40 onto the imaging plane 35 is a stationary image taken by the television camera 44. However, since the projected image other than the tomographic plane 40 is detected as a rotating image, it is detected as a blurred tomographic image.
[0022]
Next, before describing the embodiments of the present invention, it will be described that the above-described X-ray tomography inspection apparatus is extremely suitable for the inspection method for power equipment of the present invention. X-rays are electromagnetic waves generated when an accelerated electron beam collides with a metal target, and the wavelength thereof ranges from 0.0001Å to 10Å (1Å = 1 × 10). ^-Ten m). Therefore, X-rays have a wavelength much shorter than that of visible light or ultraviolet light, and are therefore extremely suitable for nondestructive inspection by X-ray tomography. However, conventionally, the field in which non-destructive inspection by X-ray tomography is used is inspection of fine parts such as semiconductor defect inspection and wiring pattern inspection.
[0023]
On the other hand, as described above, the power equipment to which the present invention is applied is extremely large and heavy, such as a transformer, insulator, lightning rod parts, etc. There was no knowledge of whether non-destructive inspection equipment can be used. The present inventors have repeated experiments and obtained the following findings. That is, the quality of X-rays has a degree to express the ease of transmission of a substance, and soft X-rays are X-rays that are difficult to transmit a substance and have a large attenuation, and have a long wavelength. Hard X-rays are X-rays that are easily transmitted through a substance and have low attenuation, but have a short wavelength. This relationship is as shown in Table 1.
[0024]
[Table 1]

From the above characteristics, when performing projection by X-ray, it is considered as follows. When the object to be projected is thin or the object is light in weight, if a hard X-ray is used, there is little attenuation, and a photographic image with no contrast is obtained in which the difference in thickness of the object is difficult to occur. Conversely, if soft X-rays are used when the object is thick and has a heavy mass, the X-rays do not pass through. Therefore, when performing projection imaging with X-rays, it has been found that it is necessary to appropriately select a tube voltage that generates X-rays depending on the target power equipment, and insulation used in transformers that are power equipment. It was found that the soft X-ray region is effective for observing the internal state of the resin, that is, migration, cracks, pinholes, and the like.
[0025]
According to the experiment, the relationship between the tube current of the X-ray tube generating X-rays and the intensity of the X-ray with respect to the tube voltage is as shown in FIGS. FIG. 4 is a graph showing the relationship between the intensity (I) of X-rays when the tube current is constant and the wavelength λ, and FIG. 5 is the intensity (I) of X-rays and wavelength when the tube voltage is constant. It is a figure which shows the relationship with (lambda). As is apparent from FIG. 4, when the tube voltage is increased, hard X-rays having a short wavelength increase (the hatched portion in FIG. 4), and when transmitted through the object, a transmission image with low attenuation and low contrast is obtained. It is unsuitable as an image. Therefore, as shown in FIG. 5, when the tube voltage is set according to the type of the object to be transmitted, it is necessary to adjust the tube current to change the X-ray intensity, and to adjust the brightness of the transmitted elephant that is easy to observe. Yes. Therefore, according to this knowledge, the present inventors control the tube voltage and tube current of the X-ray tube by the control device 46 shown in FIG. 3 to obtain a tube voltage (shown in FIG. 5) that generates soft X-rays. The X-ray intensity was changed by setting and adjusting the tube current and adjusted so as to obtain a tomographic image that was easy to observe.
[0026]
Next, an X-ray tomographic image inspection apparatus used in the present invention will be described with reference to FIG. Reference numeral 80 denotes an X-ray tube that generates X-rays 81 in a radial manner and generates soft X-rays for observing migration, cracks, pinholes, or the like of a resin insulating member constituting the transformer. Reference numeral 82 denotes an image pickup unit, which is not shown in detail, and includes the image pickup surface 35, the fluorescence multiplier 41, the image rotation prism 42, and the image storage type image pickup device 44 shown in FIG. Reference numeral 84 denotes an XY table on which an inspection object, which is a heavy object such as a high-voltage transformer, is placed and used to move the object in the X and Y directions. Reference numeral 84 denotes a rotating bearing mechanism that rotates the XY table 83 and the inspection object placed on the XY table around the rotating shaft 85 (corresponding to the rotating shaft 25 in FIG. 2). Note that the driving portion and the like are omitted. Reference numeral 86 denotes a base such as a floor, which is configured to have sufficient strength to install an X-ray tomography inspection apparatus for nondestructive inspection of a high voltage transformer having a capacity of 200 kg or more. Reference numeral 87 denotes a hole provided in the base 86 for arranging the imaging unit 82. Reference numeral 88 denotes a floor surface. In particular, the rotary bearing mechanism 84 rotates the XY table 83 and a heavy object such as a power device mounted on the XY table around the rotary shaft 85, so that the rotary bearing can be rotated extremely stably. The mechanism unit 84 and the XY table 83 are arranged almost horizontally together with the floor surface 88.
[0027]
Thus, in this X-ray tomogram inspection apparatus, the X-ray tube 80 is disposed above the base 86, and the imaging unit 82 is disposed inside the hole 87 provided in the base 86. A sample stage (corresponding to the XY table 83) on which the inspection object is placed is arranged in the meantime, but in the case of this apparatus, an extremely heavy transformer or the like is placed, so that the sample stage is the floor surface or the same. It shall be installed on a stand with equivalent strength.
[0028]
Further, the rotary bearing mechanism 84 of the sample stage is configured to be embedded in the floor surface, and the XY table 83 is a mechanism that moves on the floor surface. This is a structure devised to measure heavy objects, and is intended to facilitate the attachment of heavy objects and the sample stage that supports the weight, that is, the XY table 83 and the rotary bearing mechanism 84. The imaging unit 82 is disposed below the floor surface 88, and an XY-direction adjustment mechanism for aligning the image rotation prism (corresponding to the image rotation prism 42 in FIG. 3) of the imaging unit 82 and the rotation axis 85 of the sample stage. (Not shown).
[0029]
As described above, since the X-ray tomography apparatus used in the present invention is configured as described above, the X-ray tomography apparatus can easily inspect the inside of a heavy object such as a transformer without destruction. Thus, it has become possible to easily inspect for defects such as migration, cracks, pinholes, etc., inside the transformer, which have been non-destructive and impossible to inspect.
[0030]
Next, an embodiment of the present invention will be described. In this embodiment, for example, when a high voltage transformer to be inspected is placed on the sample stage 83 of the X-ray tomography inspection apparatus shown in FIG. 8, and soft X-rays are irradiated from this to the X-ray tube 80 The inspection method will be described. FIG. 6 shows a cross-sectional shape of a part of the high-voltage transformer placed on the sample stage 83, that is, a part of the epoxy mold transformer. In FIG. 6, 61 shows a cross section of a part of the epoxy molded transformer, 62 is a coil block of copper wire divided into blocks, and 63 is an epoxy resin layer molded to insulate the coil portion. 64 is an enlarged view of a circular portion of the portion 61 of the epoxy mold transformer, 65 is a copper wire, and 66 is an epoxy resin layer. FIGS. 1, 7 and 9 show tomographic images of the epoxy mold transformer as seen through X-rays. In this inspection, as described with reference to FIG. 3, the tube voltage and tube current of the X-ray tube 80 are controlled by a control device (not shown in FIG. 8, corresponding to the control device 46 of FIG. 3). Adjusted.
[0031]
FIG. 7 is an X-ray tomographic image photographed according to the present invention, and is a tomographic image of a part of the epoxy mold transformer when viewed through the tube voltage of the X-ray tube 80 at 70 KV and a tube current of 80 μA. In FIG. 7, 71 is a copper wire, 72 is an epoxy resin layer, and the portion that appears to be two layers is because the type of resin is different. FIG. 9 is a partially enlarged view of FIG. As can be seen from this photograph, there is evidence of resin flowing around the copper wire. This is considered to have been made when an epoxy resin was injected during mold formation. As can be seen from FIGS. 7 and 9, no internal defects such as migration, cracks or pinholes are found in the X-ray tomographic image of this epoxy mold transformer. Therefore, it turns out that it is an epoxy mold transformer without deterioration and a defect.
[0032]
Thus, FIG. 1 is an enlarged view of a tomographic image of a portion of the epoxy mold transformer as seen through the tube voltage 70 KV and tube current 80 μA of the X-ray tube 80. In the figure, 1 is a conductive wiring material made of copper (Cu), 2 is an epoxy resin, and insulates between the conductive materials 1. 3 is migration, and the state in which copper grows in a mycelium shape in a high-temperature and high-humidity environment and extends in the insulating resin is observed. 4 shows the flow of the resin generated when the insulating resin is formed. No. 5 is a crack, which is considered to have occurred along the flow of the resin due to repeated drying and expansion / contraction of the resin due to aging. As can be seen from FIG. 1, migration and cracking of the epoxy resin inside the high-voltage transformer are non-destructive and can be inspected. Therefore, if this X-ray tomographic image inspection method is used, it is possible to periodically inspect the deterioration state of the power equipment, to maintain the power equipment, to predict the lifetime, and to prevent accidents.
[0033]
Hereinafter, an embodiment of the inspection method will be described with reference to FIG. FIG. 10 shows a flow of a method of shipping a product such as a power device from a manufacturing factory or the like, installing it at a site such as a substation, and then periodically inspecting it for maintenance inspection. The left column of FIG. 10 is the step at the shipping factory, the central data server column is the processing step of the computer room of the management department in the electric power company, maintenance service company, manufacturer, etc. The column shows the processing steps at the substation site.
[0034]
First, the flow of the inspection method starts from start 100 and proceeds to initial data creation 101 (step 1). In step 1, initial data is created in accordance with maintenance inspection items determined in advance for each product at the time of product inspection at the time of shipment from the factory.
Step 1: Create initial data. Initial data is created, recorded in the data server 102 and stored. This initial data is data that is free from defects at the time of shipment of a power device, for example, a high-voltage transformer. Images are taken at the time of shipment of the high-voltage transformer using the X-ray tomography inspection apparatus shown in FIG. Shooting conditions such as inspection images, shooting dates, shooting conditions, that is, tube voltage, tube current, number of integrations, density adjustment data, shooting position (XY coordinates, angle, etc.), etc. However, it is necessary to determine so that the comparison can be made with good reproducibility. For this purpose, the processing unit and the recording unit in the control unit 46 of FIG. 3 are used. It should be noted that it is desirable to limit the shooting locations to locations where deterioration is expected to progress from past experience. In this case, the shooting time is shorter and the recording capacity of the data server 102 is smaller. The X-ray tomogram thus imaged is stored in the data server 102 together with the imaging conditions, for example, in a table as shown in Table 2.
[0035]
[Table 2]

The table of Table 2 will be described. Imaging locations A, B,... N indicate, for example, X-ray tomographic imaging locations of the epoxy mold transformer shown in FIG. The inspection data at the time of shipment is an X-ray tomographic image obtained when an X-ray tomographic image at each imaging location is imaged by the X-ray tomographic image inspection apparatus in FIG. For example, Photo A-1 is an X-ray tomographic image shown in FIG. Photo B-1,... Photo N-1 is also an X-ray tomographic image of another part of the epoxy mold transformer. At the same time, the above-described tube voltage, tube current, number of integrations, density adjustment data, photographing position, and the like are recorded as photographing conditions in the photographing condition area. For example, shooting conditions under which the photograph A-1 at the time of shipment was taken, that is, a tube voltage of 70 KV, a tube current of 80 μA, and the like are recorded.
[0036]
The product for which inspection has been completed is transported to a site such as a substation and installed (103), and operation (104) is started. After the predetermined period has elapsed, periodic inspection data creation 105 (step 2) is performed. Note that for data that has been damaged by this periodic inspection, the data in the data server 102 is corrected by the steps of damage 106 and inspection data correction 107, and the damaged power device is discarded and replaced with a new power device. The
[0037]
Step 2: Collect first inspection data. This is a regular inspection in operation, and the first inspection data is collected. As the first inspection data, for example, X-ray tomograms taken under the same imaging conditions at the same site with the same epoxy mold transformer five years after shipment, the first inspection data is the data server The table 102 is recorded in Table 2. Photo A-2 is an X-ray tomogram taken at the same location as Photo A-1 at the location A of the epoxy mold transformer. For example, the X-ray tomogram shown in FIG. 1 corresponds to this. The second inspection data shown in Table 2 is a place where the inspection data at that time is accumulated when the inspection after 3 to 5 years is necessary. Note that the X-ray tomographic image taken at the time of shipment and the X-ray tomographic image of the first inspection data need to be located at almost the same location, even if the imaging conditions are the same. May be slightly off. Therefore, in order to improve the accuracy, the X-ray tomographic image at the time of shipment is compared with the X-ray tomographic image of the first inspection data, and it is determined whether or not the positions match. Thus, it is desirable to take an X-ray tomographic image of the first inspection data.
[0038]
Next, in comparison 108 with the actual product data (step 3 and step 4), the initial data of the same product and the first inspection data are compared to determine the state of deterioration.
[0039]
Step 3: Image comparison. X-ray tomograms are compared. The product change is determined by comparing a photograph of the inspection data taken at the time of shipment and a photograph of the first inspection data. For example, the comparison is made between a photograph A-1 (shown in FIG. 9) and a photograph A-2 (shown in FIG. 1). There are various comparison methods, and a method well known as image processing is a method in which an image is divided into pixels (pixels) and compared with luminance levels in units of pixels. A method of dividing into areas and comparing luminance levels for each area or a method of calculating histograms of images and comparing the shapes of the histograms is used. Or they can be used in combination to enhance the inspection system. As a result of the comparison, when a difference occurs between the photograph A-1 and the photograph A-2, it is detected that the material constituting the epoxy mold transformer has changed.
[0040]
Step 4: Judgment of deterioration: From the above image comparison, for example, when the luminance level and the shape of the histogram have changed by 30% or more, take measures such as replacing the high-voltage transformer because of the deterioration. To determine how much change is required, whether or not the power equipment needs to be replaced is determined by accumulating various experimental data, shipping data and product inspection data after several years. Of course, it is necessary to judge, but according to the inspection data of the present inventors, migration, cracks and pinholes are detected as follows.
[0041]
Detection of migration: As is clear from comparison of Photo A-1 and Photo A-2, Migration 3 is a whisker-like shape that grows in the resin, is the same copper member as the wire, and is darker than the resin part. Become. Therefore, the determination can be made based on the luminance level of the comparison image. Moreover, as a judgment of the degree of deterioration, if the length of the migration 3 grows to a length exceeding 50% of the distance between the conductive wiring members 1, the high voltage transformer is deteriorated and it is time to replace.
[0042]
Crack detection: Photo A-1 and Photo A-2 are compared, but brightness correction is required. The brightness correction uses an offset in the brightness direction when the best match is obtained when matching the histograms. Then, if there is a crack larger than a certain area in the detected data, it is replaced. Alternatively, the crack is formed by cracking the resin, is considered as an air layer, and has a brightness level brighter than the brightness level of the resin portion. Therefore, since the crack can be determined by detecting the luminance level of the difference image, it can be determined that there is a crack having a certain area or more.
[0043]
Pinhole detection: Similar to crack detection, but a circular shape is determined as a pinhole.
[0044]
Based on the result of the determination as described above, whether or not to continue the operation of the electric power device is determined 110. If the device still withstands the operation sufficiently, the operation continues, and if the device has deteriorated, the process proceeds to the discard 111. To be replaced with a new one.
[0045]
In addition, in FIG. 10, the comparison 109 (step 5 and step 6) with the data outside the actual product is further provided. This is because, apart from the comparison 108 with the above-mentioned actual product data, the deterioration data of another power device of the same type, in the case of this example, another epoxy mold transformer that has been inspected before is stored in the data server 102. Then, the X-ray tomogram which is the deterioration data of another epoxy mold transformer inspected before is compared with the X-ray tomogram of the first inspection data to determine the deterioration. Of course, the comparison 109 (steps 5 and 6) with data outside the actual product is not necessarily required, but is a necessary step in order to increase the accuracy of the determination of deterioration.
[0046]
Step 5: Image comparison. Here, an X-ray tomogram that is a deterioration data of another epoxy mold transformer that has been inspected before and an X-ray tomogram of the first inspection data are visually compared, for example, and there is a change in both. Judge whether there is.
[0047]
Step 6: Determination of deterioration. Here, the state of deterioration is grasped from the image comparison in step 5. In other words, if the photograph showing the past deterioration situation and the X-ray tomographic image of the first inspection data are visually compared, the deterioration situation can be grasped at a glance and it is very easy to judge the deterioration of the high-voltage transformer. It becomes.
[0048]
As described above, migration, cracks, and pinholes can be detected by nondestructive operation. In addition, among what is detected by the difference image, what is considered to be the flow of resin is also detected, but this is determined visually. Of course, if the images completely match, detection is not performed, and it goes without saying that it can be removed by appropriately setting a threshold for the detection level.
[0049]
As described above, it can be seen that the X-ray tomographic image inspection method of the present invention can inspect heavy objects such as electric power equipment in a non-destructive manner. In addition, migration, cracks, pinhole growth processes, and the like can be inspected from the inspection results, so that it is possible to determine the degree of deterioration of power equipment and the like.
[0050]
Note that the control unit (not shown) of the X-ray tomography apparatus analyzes the X-ray transmission image captured by the imaging unit 82 as electronic data as necessary in addition to the function of storing the X-ray transmission image in the storage device. Needless to say, it also has a function of analyzing material deterioration of the high-voltage substation equipment and a function of storing or managing the analysis result. Also, the electronic data of the X-ray transmission image can be sent to a base station such as a power company via a public line (for example, ADSL).
[0051]
Although the present invention has been described in detail above, the present invention is not limited to the X-ray tomographic image inspection method described herein, but besides the above, an apparatus for inspecting the inside of a power device or the like nondestructively Needless to say, it can be widely applied to methods.
[0052]
【The invention's effect】
As described above, there is no conventional method for directly inspecting internal degradation of high-voltage equipment such as power equipment and heavy objects, and the cause of degradation of power equipment is due to migration of insulating resin, cracks, pinholes, etc. Although it was thought that it was a thing, the method of inspecting this directly has not been realized until now. The present invention realizes an X-ray tomographic image inspection method for power equipment that can directly observe non-destructive degradation of the power equipment, enables regular inspection of the power equipment, and reduces the replacement cost of the power equipment used. In addition, major accidents can be prevented in advance, and for the life prediction of power equipment, various experimental data, shipping data and product inspection data after several years are accumulated and analyzed, An extremely useful X-ray tomographic image inspection method, which is possible by making a judgment, has been realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing an X-ray tomographic image of one embodiment of the present invention.
FIG. 2 is a diagram for explaining the principle of the present invention.
FIG. 3 is a diagram showing a basic configuration of an X-ray tomographic image inspection apparatus used in the present invention.
FIG. 4 is a diagram showing the X-ray intensity when the tube current is constant for explaining the operation of the X-ray tomography apparatus used in the present invention.
FIG. 5 is a diagram showing the X-ray intensity when the tube voltage is constant for explaining the operation of the X-ray tomography apparatus used in the present invention.
FIG. 6 is a cross-sectional view of a part of the high-voltage transformer used for the inspection according to the present invention.
FIG. 7 is a diagram showing an example of a tomographic image obtained by the inspection method of the present invention.
FIG. 8 is a diagram showing an example of an X-ray tomographic image inspection apparatus used in the present invention.
FIG. 9 is a diagram showing an example of a tomographic image obtained by the inspection method of the present invention.
FIG. 10 is a diagram showing an embodiment of the present invention.
[Explanation of symbols]
1: conductive wiring material, 2: insulating resin, 3: migration, 4: resin flow, 5: crack, 31, 80: X-ray tube, 32: X-ray generation point, 34: optical axis, 35: imaging surface, 36: XY movement mechanism, 37: rotary table, 38, 81: rotary axis of rotary table, 39: object, 40: tomographic plane, 41: fluorescence multiplier, 42: image rotation prism, 43: rotation of image rotation prism Axis, 44: image storage type imaging device, 46: control device, 47: display device, 86: base, 87: hole in the base, 88: floor surface.

Claims (4)

A mounting table that rotates about a vertical axis and on which power equipment is mounted; an X-ray generator that generates X-rays and is arranged so that an optical axis of the X-rays is inclined with respect to the vertical axis; Means for converting an X-ray image transmitted through a power device mounted on the mounting table into an optical image; means for rotating the optical image in synchronization with rotation of the mounting table; and In an X-ray tomography apparatus for electric power equipment comprising means for converting to an electric signal and a control device for processing the electric signal to obtain an X-ray tomogram, the control device determines the tube voltage of the X-ray generator. While generating soft X- rays of 0.0001Å to 10Å, the tube voltage is set so as to be a constant tube voltage corresponding to the power equipment, and the control device is configured to generate tube current of the X-ray generator. X-ray tomographic image data by controlling the X-ray intensity Controls to obtain the data, during inspection the initial manufacture of the aforementioned power device stores imaging conditions at that time and the X-ray tomographic image data of a predetermined portion, the same power as the power device to which aging after a lapse yearly Accumulating X-ray tomographic image data obtained by imaging the predetermined part of the device under the same conditions as the imaging conditions, the X-ray tomographic image data of the predetermined part at the time of the inspection of the power device is the same as the power device, comparing the captured the X-ray tomogram data of aged above predetermined portion of the power device based on a predetermined criteria from the comparison result, X-rays, characterized in that to check the deterioration of the power equipment A method for inspecting electric power equipment using a tomogram inspection apparatus.   2. The method of inspecting electric power equipment by the X-ray tomography inspection apparatus according to claim 1, wherein the predetermined determination criterion is at least one determination criterion of migration, crack, or pinhole. Inspection method of electric power equipment by line tomography inspection device. The X-ray tomography method according to claim 1, wherein the X-ray tomography is the same as the power equipment, and a predetermined part of the power equipment that has changed over time is imaged under the same conditions as the imaging conditions. X-ray characterized in that image data is recorded at least twice at intervals of year, and the state of deterioration and the life of the power device are predicted from the comparison result of the X-ray tomographic image data of the power device. A method for inspecting electric power equipment using a tomogram inspection apparatus. The X-ray tomographic image inspection apparatus according to claim 1, further comprising: X-ray tomographic image data obtained by imaging a predetermined part of another power device of the same type as the power device under the same conditions as the imaging conditions. Recording, comparing the X-ray tomogram data of a predetermined part of the another degraded power device with the X-ray tomogram data of the predetermined part of the power device, and inspecting the deterioration state of the power device. A method for inspecting electric power equipment using an X-ray tomography apparatus.

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