JP2004219091A

JP2004219091A - Temperature measuring method using radiation thermometer

Info

Publication number: JP2004219091A
Application number: JP2003003258A
Authority: JP
Inventors: Takashi Kamiyama; 隆神山; Noriyasu Matsumoto; 憲靖松本
Original assignee: Tokyo Electric Power Co Inc
Current assignee: Tokyo Electric Power Company Holdings Inc
Priority date: 2003-01-09
Filing date: 2003-01-09
Publication date: 2004-08-05
Anticipated expiration: 2023-01-09
Also published as: JP3910917B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature measuring method using a radiation thermometer for precisely measuring temperature even if measurement is made at a great distance to an object when the temperature of the object, such as a compression joint pipe and an electric wire, is measured by using the radiation thermometer. <P>SOLUTION: When the temperature of the compression joint pipe 44, such as an overhead transmission line 50, is measured by using the radiation thermometer, an instant visual field angle θ of one pixel in the radiation thermometer 10 is obtained in advance, the temperature of an already known object to be measured is detected from a blackbody furnace 13 or the like by one pixel, an already known background temperature is detected by nearby pixels 20b-20d adjacent to one pixel 20a, and a correction expression, where a radiation energy P1 in the object to be measured being detected by one pixel becomes a radiation energy A at a temperature of the object to be measured, is calculated from the radiation energy P1 in the object to be detected being detected by one pixel and the background radiation energies P1-P4 detected by each pixel nearby. Temperature is corrected, based on the above correction expression, when the temperature of the compression joint pipe 44 is measured by the radiation thermometer 10. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、鉄塔等の架空送電線とがいし或いは送電線同士を接続している圧縮接続管や電線等の対象物の温度測定方法に係り、特に、その対象物を遠く離れた位置から放射温度計を用いて測定するための放射温度計を用いた温度測定方法に関するものである。
【０００２】
【従来の技術】
送電線路の保守管理として、圧縮接続管（引留クランプ、圧縮直線スリーブ、ジャンパスリーブ、Ｔ型スリーブ、圧縮端子類など）の劣化による発熱を測定することが行われている。
【０００３】
図９は、送電線鉄塔を示したものであり、送電線５０は、がいし連５６を介して鉄塔５１の腕金５２に支持され、その送電線５０同士がジャンパ線５３で接続される。
【０００４】
圧縮接続管は、図１０（ａ）に示すように送電線５０同士を接続する直線スリーブ５５や図１０（ｂ）に示すように送電線５０をがいし連５６に接続する引留クランプ５４、その他図には示していないが、Ｔ型スリーブ、ジャンパスリーブなど種々のものがある。
【０００５】
この圧縮接続管は、劣化が進むと抵抗値が増大して電線部分に比べて発熱量が増大するため、送電線の通電中に、その発熱を検知すべく、異常温度となるとその形状が変化する形状記憶合金を圧縮接続管にコイル状に巻き付け、そのコイルピッチの変化を望遠鏡により観察することで異常加熱を検出することが知られている（特許文献１）。
【０００６】
【特許文献１】
特開２００１−１６７８６０号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、送電線路の圧縮接続管は多数であり、その圧縮接続管毎に形状記憶合金を巻き付けたのでは、コストがかかる問題がある。
【０００８】
そこで、本発明者等は、赤外線放射温度計を用いて圧縮接続管の温度を直接測定することを検討した。
【０００９】
この赤外線放射温度計を用いた圧縮接続管の温度の測定は、既設の送電線路の圧縮接続管すべてを測定でき、しかも、安価に測定できる利点がある。
【００１０】
ところで、圧縮接続管は、細く、しかも鉄塔の腕金近傍の高い位置にあるため、圧縮接続管が、赤外線放射温度計の瞬時視野角（空間分解能）に十分に収まるまで近づいて測定することは困難であり、どうしても遠い位置からの測定になってしまい、市販されている現状の放射温度計では、圧縮接続管の温度を精度良く測定することは困難であることが分かった。
【００１１】
測定に用いた放射温度計のセンサの画素数は、７６，８００画素（横３２０画素×縦２４０画素）であり、その画素毎に温度が測定可能とされており、圧縮接続管が１画素内に収まれば、その温度は測定できるとされているが、現実には、圧縮接続管が１画素に収まりその温度を測定しても実際の温度とは大きな隔たりがあった。
【００１２】
この理由は、上述のように７６，８００画素あり、各画素は基準温度の補正や放射率の補正などが施されるため、１画素は、その周囲の画素の温度影響を受けて温度を表示することに起因するものと思われ、１画素周りの温度が大きく違った場合には、その画素の温度を正確に表示することはできない。
【００１３】
実際に放射温度計のメーカ推奨値では、７６，８００画素中のある画素において、１つの画素が実際に観ている範囲は、被測定物の温度が一様であった場合、１画素は、３×３画素の範囲で９０％、５×５画素の範囲で１００％の放射エネルギーを測定できるとしている。
【００１４】
また、この放射温度計は、その瞬時視野角（空間分解能）が、標準レンズで１．３ｍｒａｄ、５°の望遠レンズを用いても０．２９ｍｒａｄが限度であり、圧縮接続管の径にもよるが、２０ｍｍの径の直線スリーブの温度測定には、標準レンズを用いたとき、少なくとも５ｍ程度、４０ｍｍの径で１０ｍ程度近づかなくては精度良い測定はできないこととなり、放射温度計による温度測定は現実的に困難である。
【００１５】
実際に、６６ｋＶ、１５４ｋＶ、２７５ｋＶ以上の電圧階級の送電線で、圧縮接続管に現実に近づける位置で測定した場合に、９０％以上の精度で測定できる圧縮接続管の全設備数に対する割合は、６６ｋＶ送電線で５．４％、１５４ｋＶ送電線で５．０％、２７５ｋＶ以上の送電線で２６．０％程度しか測定ができないことが判明した。
【００１６】
そこで、本発明の目的は、上記課題を解決し、放射温度計を用いて圧縮接続管や電線などの対象物の温度を測定するに際し、対象物に対してより遠くの位置で測定しても精度良く温度を測定することができる放射温度計を用いた温度測定方法を提供することにある。
【００１７】
【課題を解決するための手段】
上記目的を達成するために請求項１の本発明は、架空送電線の圧縮接続管や電線などの対象物を放射温度計を用いて温度測定するに際して、放射温度計の１画素の瞬時視野角を予め求め、その１画素で黒体炉などから既知の被測定物温度を検出させると共にその１画素と隣接する近傍の画素に既知の背景温度を検出させ、その１画素が検出した被測定物放射エネルギーと近傍の各画素が検出した背景放射エネルギーとから１画素で検出した被測定物放射エネルギーが被測定物温度の放射エネルギーとなる補正式を算出しておき、その放射温度計で圧縮接続管の温度を測定する際に上記補正式を基に温度補正を行うようにした放射温度計を用いた温度測定方法である。
【００１８】
請求項２の発明は、被測定物温度から求められる放射エネルギーをＡ、背景温度から求められる放射エネルギーをＢとし、被測定物温度を検出した１画素の放射エネルギーＰの重み付け係数をａ、１画素を中心に、背景温度を検出した縦横１近傍の画素の重み付け係数をｂ、斜め１近傍の画素の重み付け係数をｃ、縦横２近傍の画素の重み付け係数をｄ、斜め２近傍の画素の重み付け係数をｅとし、その各画素の放射エネルギーを基に、式を算定すると、
被測定物が１×１の範囲のとき、
Ａ＝（Ｐ−４ｂＢ−４ｃＢ−４ｄＢ−８ｅＢ）／ａ
被測定物が３×３の範囲のとき、
Ａ＝（Ｐ−４ｄＢ−８ｅＢ）／（ａ＋４ｂ＋４ｃ）
被測定物が５×５の範囲のとき、
Ａ＝Ｐ
とし、
重み付け係数ａ〜ｅは、黒体炉などから既知の温度を１画素に入力すると共にその近傍の画素に既知の背景温度を入力し、これら温度と各画素が検出したエネルギーから予め求めておく請求項１記載の放射温度計を用いた温度測定方法である。
【００１９】
請求項３の発明は、対象物が、圧縮接続管や電線など細長であり、その幅が１画素の範囲のとき、
Ａ＝（Ｐ−２ｂＢ−４ｃＢ−２ｄＢ−８ｅＢ）／（ａ＋２ｂ＋２ｄ）
対象物の幅が３画素の範囲のとき、
Ａ＝（Ｐ−２ｄＢ−４ｅＢ）／（ａ＋４ｂ＋４ｃ＋２ｄ＋４ｅ）
対象物の幅が５画素の範囲のとき、
Ａ＝Ｐ
として求める請求項２記載の放射温度計を用いた温度測定方法である。
【００２０】
請求項４の発明は、対象物の幅をＷ、１画素の１片の大きさをｒとし、対象物の幅Ｗが１画素以上３画素未満の範囲のとき、
Ａ＝（Ｐ−βＢ）／α
但し、
α＋β＝１、
α＝ａ＋ｂ（１＋Ｗ／ｒ）＋２ｃ（Ｗ／ｒ−１）＋２ｄ＋２ｅ（Ｗ／ｒ−１）、
β＝ｂ（３−Ｗ／ｒ）＋２ｃ（３−Ｗ／ｒ）＋２ｄ＋２ｅ（５−Ｗ／ｒ）、
として求める請求項３記載の放射温度計を用いた温度測定方法である。
【００２１】
請求項５の発明は、対象物の幅をＷ、１画素の１片の大きさをｒとし、対象物の幅Ｗが３画素以上５画素未満の範囲のとき、
Ａ＝（Ｐ−βＢ）／α
但し、
α＋β＝１、
α＝ａ＋４ｂ＋４ｃ＋ｄ（Ｗ／ｒ−１）＋２ｅ（Ｗ／ｒ−１）
β＝ｄ（５−Ｗ／ｒ）＋２ｅ（５−Ｗ／ｒ）
として求める請求項３記載の放射温度計を用いた温度測定方法である。
【００２２】
請求項６の発明は、放射温度計で圧縮接続管や電線など細長の対象物の熱画像を撮影する際に、その細長の対象物が熱画像に対して水平になるように放射温度計をロールさせて撮影する請求項１〜５いずれかに記載の放射温度計を用いた温度測定方法である。
【００２３】
【発明の実施の形態】
以下、本発明の好適な一実施形態を添付図面に基づいて詳述する。
【００２４】
先ず、放射温度計の一つの画素がどれぐらいの範囲まで測定しているのか（視野の広がり）について図４、図５により説明する。
【００２５】
先ず、図５に示すように、現在圧縮接続管や電線の温度測定に使用する赤外線放射温度計（カメラ）１０は、その撮影面１１が、横３２０画素、縦２４０画素の７６，８００画素であり、その撮影面１１中、１画素が１つの温度として表示している領域１２は、放射温度計１０と被測定物までの距離Ｌで、その大きさも異なるが、１画素の範囲の瞬時視野角（空間分解能）θは、１．３ｍｒａｄとなっている。
【００２６】
そこで、図４（ａ）、（ｂ）に示すように、１画素が正しく温度測定がなされるか、黒体炉１３を用いて、１画素の測定温度を測定した。
【００２７】
この場合、図４（ｂ）に示すように黒体炉１３の赤外線出口窓１４を、１０ｍｍ×１０ｍｍ角の穴１５をあけたステンレス板１６で覆い、図４（ａ）に示すように放射温度計１０の光軸Ｏを、黒体炉１３の窓１４を覆ったステンレス板１６の穴１５の中心に一致するようにし、瞬時視野角（空間分解能）θを考慮して黒体炉１３と放射温度計１０との距離Ｌθ（この場合７．５ｍ）を調節して、穴１５が１画素に収まるようにした。
【００２８】
また、比較のため穴径３０ｍｍ×３０ｍｍ角のステンレス板も用いて測定を行った。
【００２９】
測定は、黒体炉の温度を５０℃、７９℃、１１８℃として、穴に相当する放射エネルギーを測定した。また、穴周りのステンレス板温度（背景温度）は２４℃に保った。
【００３０】
ここで、測定される温度をＴとすると、画素での放射エネルギーＥの算出式は、下式となる。
【００３１】
Ｅ＝２１８０００／［｛ｅｘｐ（１４８８．６／（Ｔ＋２７３）｝−１］
上記式より、Ｔ＝５０℃の放射エネルギーは、Ｅ＝２１９４
Ｔ＝７９℃の放射エネルギーは、Ｅ＝３２２３
Ｔ＝１１８℃の放射エネルギーは、Ｅ＝４９５２
であり、また背景温度２４℃の放射エネルギーは、Ｅ＝１４６１
である。
【００３２】
しかし、実際に、それぞれ３回測定した１画素相当分の放射エネルギーは、
Ｔ＝５０℃（Ｅ＝２１９４）で、２０１８（４４．３℃）、１９７９（４３．０℃）、１９９１（４３．４℃）であり、
Ｔ＝７９℃（Ｅ＝３２２３）で、２７７０（６７．０℃）、２７０２（６５．１℃）、１９９１（６３．０℃）であり、
Ｔ＝１１８℃（Ｅ＝４９５２）で、４０３４（９８．４℃）、３９７７（９７．１℃）、３９４６（９６．４℃）であり、背景温度の影響を大きく受けて正しい放射エネルギーＥを示さない。
【００３３】
これに対して、３０ｍｍ×３０ｍｍの穴のステンレス板を用いた放射エネルギーは、９０％以上の測定精度を示した。
【００３４】
この１０ｍｍ×１０ｍｍの穴の１画素を中心とした近傍の画素の放射エネルギーを調べたところ、背景温度の放射エネルギーの測定値は、５０℃で、約１５５０〜１４６０と背景放射エネルギー（Ｅ＝１４６１）に対して０〜９０程度放射エネルギーが高く、７９℃で、放射エネルギー範囲が約１５８０〜１４６０と背景放射エネルギー（Ｅ＝１４６１）に対して０〜１２０程度放射エネルギーが高くなり、１１８℃で、放射エネルギー範囲が約１７１０〜１４６０と背景放射エネルギー（Ｅ＝１４６１）に対して０〜２５０程度放射エネルギーが高くなっていることが分かった。
【００３５】
このことは、被測定物が１画素に収まっていても、その画素は背景温度の影響を受け、逆にその１画素近傍の画素は、被測定物の画素の測定温度の影響を受けていることを示している。
【００３６】
そこで、１画素を中心に近傍の画素（５×５画素）について、ステンレス板を１画素ずつ移動させて、それぞれの画素の放射エネルギーを測定した。
【００３７】
図６は、５×５画素２０（但し５×５画素中の４隅の画素は影響を受けないために無視して合計２１画素とする）の感知範囲モデルを示したものである。
【００３８】
先ず、図６（ａ）は、５×５画素２０の中心画素２０ａに穴が位置して黒体炉の温度を測定する場合（条件１）、図６（ｂ）は、中心画素２０ａに対して上下左右に１近傍ずらした画素２０ｂに穴が位置した場合（条件２）、図６（ｃ）は、中心画素２０ａに対して斜めに１近傍ずらした画素２０ｃに穴が位置した場合（条件３）、図６（ｄ）は、中心画素２０ａに対して上下左右に２近傍ずらした画素２０ｄに穴が位置した場合（条件４）、図６（ｅ）は、中心画素２０ａに対して斜めに２近傍ずらした画素２０ｅに穴が位置した場合（条件５）を示している。
【００３９】
この図６で、各画素には、被測定物の放射エネルギーＡが入射するときにＡを表示し、背景エネルギーＢが入射するときにＢを表示し、中心画素２０ａに係数ａを、中心画素２０ａ（係数ａ）に対して、上下左右１近傍に係数ｂ、斜め１近傍に係数ｃ、上下左右２近傍に係数ｄを、斜め２近傍に係数ｅを付与して重み付けを行って表示した。
【００４０】
そこで、各条件１〜５での表示エネルギーＰ１〜Ｐ５としたとき、
条件１：Ｐ１＝ａＡ＋４ｂＢ＋４ｃＢ＋４ｄＢ＋８ｅＢ
条件２：Ｐ２＝ａＢ＋３ｂＢ＋４ｃＢ＋４ｄＢ＋８ｅＢ＋ｂＡ
条件３：Ｐ３＝ａＢ＋４ｂＢ＋３ｃＢ＋４ｄＢ＋８ｅＢ＋ｃＡ
条件４：Ｐ４＝ａＢ＋４ｂＢ＋４ｃＢ＋３ｄＢ＋８ｅＢ＋ｄＡ
条件５：Ｐ５＝ａＢ＋４ｂＢ＋４ｃＢ＋４ｄＢ＋７ｅＢ＋ｅＡ
となる。
【００４１】
但し、ａ＋４ｂ＋４ｃ＋４ｄ＋８ｅ＝１である。
【００４２】
次に、図７は、被測定物が５×５画素２０のどの範囲にあるかを示した図で、図７（ａ）は、被測定物が、１×１の画素の範囲にある場合、図７（ｂ）は、被測定物が、３×３の画素の範囲にある場合、図７（ｃ）は、被測定物が、５×５の画素の範囲にある場合を示している。
【００４３】
図７（ａ）の１×１画素の場合の真のエネルギー算出式は、
Ａ＝（Ｐ−４ｂＢ−４ｃＢ−４ｄＢ−８ｅＢ）／ａ
となる。
【００４４】
但し、斜め２近傍の係数ｅは、略ゼロに近いため、算出式を簡便にするため、
Ａ＝（Ｐ−４ｂＢ−４ｃＢ−４ｄＢ）／ａ
とした。
【００４５】
また図７（ｂ）の３×３画素が被測定物の放射エネルギーが入射する場合の真のエネルギー算出式は、
Ａ＝（Ｐ−４ｄＢ−８ｅＢ）／（ａ＋４ｂ＋４ｃ）
となり、同様に、斜め２近傍の係数ｅは、略ゼロに近いため、算出式を簡便にするため、
Ａ＝（Ｐ−４ｄＢ）／（ａ＋４ｂ＋４ｃ）
とした。
【００４６】
さらに図７（ｃ）の５×５画素が被測定物の放射エネルギーが入射する場合の真のエネルギー算出式は、
Ａ＝Ｐ
であり、補正式は不要となる。
【００４７】
次に、これら係数ａ〜ｄを求めた結果を図８により説明する。
【００４８】
図８は、図４、図６で説明したように、被測定物温度（黒体温度）が５０℃（図８（ａ））、７９℃（図８（ｂ））、１１８℃（図８（ｃ））の場合の各画素の温度、各画素の放射エネルギー、近傍画素毎の放射エネルギーの平均をそれぞれ示したものである。
【００４９】
この図８（ａ）〜図８（ｃ）においては、説明の便宜上、各黒体温度に対して１データしか示していないが、放射温度計の補正式となる係数ａ〜ｄをより正確に求めるためには、多数温度を測定しておく。
【００５０】
さて、中心画素（係数ａ）の表示エネルギーをＰ１とし、近傍画素の表示エネルギー値を、上下左右１近傍の画素（係数ｂ）の平均表示エネルギー値をＰ２、斜め１近傍の画素（係数ｃ）の平均エネルギー値をＰ３、上下左右２近傍の画素（係数ｄ）の平均表示エネルギー値をＰ４とし、上記条件１〜４の式（但し、係数ｅはゼロ）から、それぞれのＰ１〜Ｐ４の表示エネルギーを代入して係数ａ〜ｄを求めると以下の通りとなる。
【００５１】

以下、測定をそれぞれ３回行った時の係数を下表に示す。
【００５２】

表１の全体平均の係数（ａ＝０．７１５８０３、ｂ＝０．０５３５７８、ｃ＝０．０１４７９０、ｄ＝０．００２２６３）を用いて温度を補正した結果を表２に示す。
【００５３】

またエネルギー表示では表３となる。
【００５４】

このように、１画素の温度、表示エネルギーを係数ａ〜ｄを用いて補正することで、実際の温度、放射エネルギーに対して誤差率±５％以内に納めることができ、より信頼性の高い温度測定が行える。
【００５５】
次に、温度を測定する対象物として、実際に圧縮接続管の温度を測定する例を図１により説明する。
【００５６】
図１は、赤外線放射温度計１０で、圧縮接続管として、鉄塔５１の引留クランプ５４の温度を測定する例を示している。
【００５７】
先ず、温度測定を行う引留クランプ５４と放射温度計１０までの距離Ｌを距離センサ（図示せず）で計測し、その放射線温度計１０で撮影された熱画像Ｇ中、引留クランプ５４が収まる範囲Ｓを設定すると共に、その引留クランプ５４が水平となるように赤外線放射温度計１０と三脚２２間に設けたローリング装置２４で放射温度計１０を光軸周りにロールさせることで、引留クランプ５４の温度測定部位２５に相当する画素領域２６（図では５×５画素）を水平にした状態で、その各画素２０の表示エネルギーを取り込みこれを記憶する。
【００５８】
このように、引留クランプ５４の温度測定部位２５の温度データを取り込んだならば他の部位を更に測定する。
【００５９】
図２は、放射線温度計１０で測定した画素領域２６からその温度測定部位２５を演算する温度測定装置３０のブロック図を示したものである。
【００６０】
温度測定装置３０には、送電線路毎に送電線名、鉄塔番号、送電線の線番、電線種類、圧縮接続管の種類とその圧縮接続管の番号などがデータベースとして格納された送電線路データ３１、送電線路データ３１から圧縮接続管の種類とその圧縮接続管の番号が入力されて電線外径や圧縮接続管の径のデータが格納され、かつ放射線温度計１０より、データ入力装置３２よりの圧縮接続管の温度測定部位２５の温度データを記憶する圧縮接続管データ３３、上述した重み付け係数ａ〜ｄのデータが格納された係数データ部３４、入力された測定距離から瞬時視野角を割り出す瞬時視野角割出部３５、圧縮接続管データ３３からの圧縮接続管のデータ及び温度データと瞬時視野角割出部３５からの視野角及び係数データ部３４からの係数ａ〜ｄを基に圧縮接続管の温度を上述した補正式を用いて演算する温度測定演算処理部３６と、温度測定演算処理部３６で求めた温度から圧縮接続管の良否を判定する良否判定部３７とを備え、その温度データがデータ保存部３８に格納されると共に外部のデータ保存装置３９に保存され、またデータ出力部４０よりプリンタ４１に出力されるようになっていると共に、これらデータをディスプレイ４２で表示できるようになっている。
【００６１】
またデータ入力装置３２には、測定時の天候、気温（背景温度となる）、風向、風速が入力され、圧縮接続管の周囲の背景温度が設定できるようにされ、更に測定時に送電線に流れている電流（潮流）も入力できるようになっている。
【００６２】
この温度測定装置３０は、温度測定演算処理部３６で温度を補正するにあたって、圧縮接続管データ３３からの圧縮接続管の径と、瞬時視野角割出部３５からの瞬時視野角θで、放射線温度計１０で測定した画素領域２６が、圧縮接続管のどの領域を計測しているかを判断して、上述した重み付け係数ａ〜ｄで演算するかを決定する。
【００６３】
次に、重み付け係数ａ〜ｄを用いて、実際の圧縮接続管の温度を補正する補正式を説明する。
【００６４】
先ず、図６は、係数ａ〜ｄを求めるための条件式であり、また図７は、被測定物のエネルギーが、１×１、３×３、５×５の画素範囲で説明した。しかし、実際の圧縮接続管は、細長であり、その幅Ｗは、１画素、３画素、５画素の範囲に入るが、長さ方向には５画素分が入る場合が多いため、上述した１×１、３×３、５×５の画素範囲の補正式の他に、この横方向の５画素分を考慮した補正式とする方がより正確な補正式が得られる。
【００６５】
これを図３により説明する。
【００６６】
図３（ａ）に示すように、５×５の画素２０が、圧縮接続管４４の領域に全て収まって被測定物温度を計測している場合、図３（ｂ）に示すように、上下２近傍の画素２０ｄが圧縮接続管４４からはみ出して一部背景温度を計測している場合（３×５の画素）、図３（ｃ）に示すように上下１近傍の画素２０ｂと斜め１近傍の画素２０ｃが一部背景温度を計測している場合（１×５）、更に、図３（ｄ）に示すように、中央の画素２０ａに圧縮接続管４４の温度と背景温度を同時に計測している場合とがある。
【００６７】
そこで、先ず図３（ａ）の５×５の画素２０が、圧縮接続管４４の領域に全て収まって被測定物温度を計測している場合には、温度測定演算処理部３６は、係数ａ〜ｄを用いずに、そのまま画素２０ａの表示エネルギーを測定温度（Ｐ＝Ａ）とする。
【００６８】
また、図３（ｄ）のように１画素２０ａ内に背景温度が入る場合には、演算せずに、測定不可とする。
【００６９】
図３（ｂ）の３×５画素が圧縮接続管４４の領域に入る場合には、
上述した３×３の補正式
Ａ＝（Ｐ−４ｄＢ−８ｅＢ）／（ａ＋４ｂ＋４ｃ）
中、圧縮接続管の温度を測定している画素の放射エネルギーＡが図３（ｂ）に示すように３×５＝１５画素となるため、
Ａ＝（Ｐ−２ｂＢ−４ｃＢ−２ｄＢ−８ｅＢ）／（ａ＋４ｂ＋４ｃ＋４ｅ）
で求める。
【００７０】
次に図３（ｃ）の１×５の１画素の場合
上述した補正式
Ａ＝（Ｐ−４ｂＢ−４ｃＢ−４ｄＢ−８ｅＢ）／ａ
中、圧縮接続管の温度を測定している画素の放射エネルギーＡが図３（ｃ）に示すように１×５＝５画素となるため、
Ａ＝（Ｐ−２ｂＢ−４ｃＢ−８ｅＢ）／（ａ＋２ｂ＋２ｄ）
で求める。
【００７１】
ここで、Ａは、被測定物のエネルギー、Ｂは、背景エネルギーで、空が映っていれば、その空のエネルギー、Ｐは、画素２０ａで表示されるエネルギーである。
【００７２】
また、圧縮接続管の幅が連続的に変化した場合の補正方法は、圧縮接続管の幅をＷ、１画素の１片の大きさをｒとし、圧縮接続管の幅Ｗが１画素以上３画素未満の範囲のときは、
Ａ＝（Ｐ−βＢ）／α
但し、
α＋β＝１
α＝ａ＋ｂ（１＋Ｗ／ｒ）＋２ｃ（Ｗ／ｒ−１）＋２ｄ＋２ｅ（Ｗ／ｒ−１）
β＝ｂ（３−Ｗ／ｒ）＋２ｃ（３−Ｗ／ｒ）＋２ｄ＋２ｅ（５−Ｗ／ｒ）
として求める。
【００７３】
また、圧縮接続管の幅Ｗが３画素以上５画素未満の範囲のときは、
Ａ＝（Ｐ−βＢ）／α
但し、
α＋β＝１
α＝ａ＋４ｂ＋４ｃ＋ｄ（Ｗ／ｒ−１）＋２ｅ（Ｗ／ｒ−１）
β＝ｄ（５−Ｗ／ｒ）＋２ｅ（５−Ｗ／ｒ）
として求める。
【００７４】
このように視野角θを基準に、温度測定する領域を、画素がどの程度の範囲で撮影できているかで、補正式を選択することで、更により精度の高い温度測定が行える。
【００７５】
以上において、従来では、６６ｋＶ、１５４ｋＶ、２７５ｋＶ以上の電圧階級の送電線で、圧縮接続管に現実に近づける位置で測定した場合に、９０％以上の精度で測定できる圧縮接続管の全設備数に対する割合は、６６ｋＶ送電線で５．４％、１５４ｋＶ送電線で５．０％、２７５ｋＶ以上の送電線で２６．０％程度しか測定ができなかったが、本発明では、従来の３倍の距離でも、６６ｋＶ送電線で９９．１％、１５４ｋＶ送電線で９９．７％、２７５ｋＶ以上の送電線で９２．９％の圧縮接続管の温度を精度良く測定できると判断される。
【００７６】
なお、上述の実施の形態では圧縮接続管の温度測定で説明したが、圧縮接続管に限らず、送電線、鉄塔等の細長の形状の対象物はもとより、変圧器など細長の形状ではない種々の対象物の温度測定にも、本発明が適用できることは勿論である。
【００７７】
【発明の効果】
以上要するに本発明によれば、放射温度計を用いて遠い距離からでも圧縮接続管などの対象物の温度を精度良く測定することができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態を示し、放射温度計で圧縮接続管を撮影する状態を示した図である。
【図２】本発明における温度測定装置のブロック図である。
【図３】本発明において、温度測定する圧縮接続管に対する放射温度計の画素の領域を説明する図である。
【図４】本発明において、補正式を求めるための黒体炉と放射温度計の説明図である。
【図５】本発明において、放射温度計の視野角を説明する図である。
【図６】本発明において、補正式を求めるための５×５画素の放射エネルギーと係数の関係を示す図である。
【図７】本発明において、５×５画素中の被測定物の範囲と補正式の関係を示す図である。
【図８】図４の状態で、黒体炉の温度を測定した時の放射温度計における５×５画素のの温度、表示エネルギーを示す図である。
【図９】圧縮接続管が使用される鉄塔を示す図である。
【図１０】圧縮接続管の詳細を示す図である。
【符号の説明】
１０放射温度計
１３黒体炉
２０画素
４４圧縮接続管（対象物）
５３引留クランプ（圧縮接続管）
５０送電線
５１鉄塔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for measuring the temperature of an object such as an overhead transmission line such as a pylon or an insulator or a compression connection pipe or an electric wire connecting the transmission lines, and in particular, the radiation temperature from a position far away from the object. The present invention relates to a temperature measurement method using a radiation thermometer for measurement using a meter.
[0002]
[Prior art]
As a maintenance management of a transmission line, measurement of heat generation due to deterioration of a compression connection pipe (an end clamp, a compression linear sleeve, a jumper sleeve, a T-shaped sleeve, compression terminals, etc.) is performed.
[0003]
FIG. 9 shows a power transmission tower, in which a power transmission line 50 is supported by an arm 52 of a steel tower 51 via an insulator string 56, and the power transmission lines 50 are connected to each other by a jumper wire 53.
[0004]
As shown in FIG. 10 (a), the compression connection pipe includes a straight sleeve 55 for connecting the transmission lines 50 to each other, an end clamp 54 for connecting the transmission line 50 to the insulator 56 as shown in FIG. 10 (b), and other drawings. Although not shown, there are various types such as a T-shaped sleeve and a jumper sleeve.
[0005]
The resistance of this compression connection pipe increases as deterioration progresses, and the amount of heat generated increases as compared to the electric wire part. It is known to detect abnormal heating by winding a shape memory alloy to be wound around a compression connection pipe in a coil shape and observing a change in the coil pitch with a telescope (Patent Document 1).
[0006]
[Patent Document 1]
JP 2001-167860 A
[Problems to be solved by the invention]
However, there are a large number of compression connection pipes in the transmission line, and if a shape memory alloy is wound around each compression connection pipe, there is a problem that the cost is high.
[0008]
Then, the present inventors considered directly measuring the temperature of the compression connection pipe using an infrared radiation thermometer.
[0009]
The measurement of the temperature of the compression connection pipe using the infrared radiation thermometer has the advantage that all the compression connection pipes of the existing transmission line can be measured, and the measurement can be performed at low cost.
[0010]
By the way, since the compression connection pipe is thin and located at a high position near the arm of the tower, it is not possible to measure until the compression connection pipe is sufficiently close to the instantaneous viewing angle (spatial resolution) of the infrared radiation thermometer. It was difficult to measure the temperature from a distant position, and it was found that it was difficult to measure the temperature of the compression connection pipe accurately with a commercially available radiation thermometer.
[0011]
The number of pixels of the sensor of the radiation thermometer used for the measurement is 76,800 pixels (320 horizontal pixels × 240 vertical pixels), and the temperature can be measured for each pixel. If the temperature falls within the range, the temperature can be measured. However, in reality, even if the compression connection pipe fits into one pixel and the temperature is measured, there is a large gap from the actual temperature.
[0012]
The reason for this is that as described above, there are 76,800 pixels, each of which undergoes correction of the reference temperature, correction of the emissivity, etc., so that one pixel displays the temperature affected by the temperature of the surrounding pixels. If the temperature around one pixel is significantly different, the temperature of that pixel cannot be displayed accurately.
[0013]
Actually, according to the manufacturer's recommended value of the radiation thermometer, in a certain pixel out of 76,800 pixels, the range actually observed by one pixel is as follows when the temperature of the measured object is uniform. It is stated that radiant energy of 90% can be measured in a range of 3 × 3 pixels and 100% in a range of 5 × 5 pixels.
[0014]
In addition, this radiation thermometer has an instantaneous viewing angle (spatial resolution) of only 0.29 mrad even with a standard lens of 1.3 mrad and a telephoto lens of 5 °, and depends on the diameter of the compression connection pipe. However, when measuring the temperature of a linear sleeve having a diameter of 20 mm, when using a standard lens, accurate measurement cannot be performed unless the distance is close to at least about 5 m, and a diameter of 40 mm is about 10 m. Realistically difficult.
[0015]
Actually, when measuring at a position close to reality with a compression connection pipe in a transmission line of a voltage class of 66 kV, 154 kV, 275 kV or more, the ratio to the total number of equipment of the compression connection pipe which can be measured with an accuracy of 90% or more is: It turned out that only about 5.4% can be measured with a 66 kV transmission line, 5.0% with a 154 kV transmission line, and only about 26.0% with a 275 kV or more transmission line.
[0016]
Therefore, an object of the present invention is to solve the above-described problems, and when measuring the temperature of an object such as a compression connection pipe or an electric wire using a radiation thermometer, it is also possible to measure the temperature at a position farther from the object. It is an object of the present invention to provide a temperature measuring method using a radiation thermometer that can accurately measure a temperature.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention of claim 1 provides an instantaneous viewing angle of one pixel of a radiation thermometer when measuring a temperature of an object such as a compression connection pipe or an electric wire of an overhead transmission line using the radiation thermometer. Is determined in advance, and a known object temperature is detected from a black body furnace or the like at one pixel, and a known background temperature is detected at a neighboring pixel adjacent to the one pixel, and the measured object is detected by the one pixel. From the radiant energy and the background radiant energy detected by each pixel in the vicinity, a correction formula is calculated in which the radiant energy of the DUT detected in one pixel is the radiant energy of the temperature of the DUT, and compression connection is performed with the radiation thermometer. This is a temperature measurement method using a radiation thermometer that performs temperature correction based on the above correction formula when measuring the temperature of the tube.
[0018]
According to a second aspect of the present invention, the radiant energy obtained from the object temperature is A, the radiant energy obtained from the background temperature is B, and the weighting coefficient of the radiant energy P of one pixel that has detected the object temperature is a, With the pixel as the center, the weighting coefficient of the pixel near the vertical and horizontal 1 near the background temperature is b, the weighting coefficient of the pixel near the diagonal 1 is c, the weighting coefficient of the pixel near the vertical and horizontal 2 is d, and the weighting of the pixel near the diagonal 2 When the coefficient is e and the equation is calculated based on the radiant energy of each pixel,
When the measured object is in the range of 1 × 1,
A = (P-4bB-4cB-4dB-8eB) / a
When the measured object is in the 3 × 3 range,
A = (P-4dB-8eB) / (a + 4b + 4c)
When the measured object is in the range of 5 × 5,
A = P
age,
The weighting coefficients a to e are obtained by inputting a known temperature from a black body furnace or the like to one pixel, inputting a known background temperature to a pixel in the vicinity thereof, and previously obtaining the temperature and the energy detected by each pixel. A temperature measurement method using the radiation thermometer according to item 1.
[0019]
According to a third aspect of the present invention, when the object is elongated, such as a compression connection pipe or an electric wire, and its width is within a range of one pixel,
A = (P-2bB-4cB-2dB-8eB) / (a + 2b + 2d)
When the width of the object is in the range of 3 pixels,
A = (P-2dB-4eB) / (a + 4b + 4c + 2d + 4e)
When the width of the object is within the range of 5 pixels,
A = P
A temperature measuring method using the radiation thermometer according to claim 2 which is obtained as follows.
[0020]
According to a fourth aspect of the present invention, when the width of the object is W, the size of one piece of one pixel is r, and the width W of the object is in a range of 1 pixel or more and less than 3 pixels,
A = (P-βB) / α
However,
α + β = 1,
α = a + b (1 + W / r) + 2c (W / r−1) + 2d + 2e (W / r−1),
β = b (3-W / r) + 2c (3-W / r) + 2d + 2e (5-W / r),
A temperature measurement method using the radiation thermometer according to claim 3 which is obtained as follows.
[0021]
According to a fifth aspect of the present invention, when the width of the object is W and the size of one piece of one pixel is r, and the width W of the object is in a range of 3 pixels or more and less than 5 pixels,
A = (P-βB) / α
However,
α + β = 1,
α = a + 4b + 4c + d (W / r-1) + 2e (W / r-1)
β = d (5-W / r) + 2e (5-W / r)
A temperature measurement method using the radiation thermometer according to claim 3 which is obtained as follows.
[0022]
According to the invention of claim 6, when a thermal image of an elongated object such as a compression connection pipe or an electric wire is taken by the radiation thermometer, the radiation thermometer is arranged so that the elongated object is horizontal to the thermal image. A temperature measurement method using a radiation thermometer according to any one of claims 1 to 5, wherein the temperature is measured by rolling.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0024]
First, the extent to which one pixel of the radiation thermometer measures (expansion of the visual field) will be described with reference to FIGS.
[0025]
First, as shown in FIG. 5, an infrared radiation thermometer (camera) 10 currently used for measuring the temperature of a compression connection pipe or an electric wire has an imaging surface 11 of 320 pixels wide and 240 pixels high, of 76,800 pixels. An area 12 in which one pixel is displayed as one temperature in the photographing surface 11 is different in the distance L between the radiation thermometer 10 and the object to be measured, and has a different size. The angle (spatial resolution) θ is 1.3 mrad.
[0026]
Therefore, as shown in FIGS. 4A and 4B, the temperature of one pixel was measured correctly or the measured temperature of one pixel was measured using the black body furnace 13.
[0027]
In this case, as shown in FIG. 4B, the infrared exit window 14 of the black body furnace 13 is covered with a stainless plate 16 having a hole 15 of 10 mm × 10 mm square, and the radiation temperature is changed as shown in FIG. The optical axis O of the total 10 is made to coincide with the center of the hole 15 of the stainless steel plate 16 covering the window 14 of the black body furnace 13 and the radiation with the black body furnace 13 in consideration of the instantaneous viewing angle (spatial resolution) θ. The distance Lθ from the thermometer 10 (in this case, 7.5 m) was adjusted so that the hole 15 could fit in one pixel.
[0028]
For comparison, the measurement was performed using a stainless steel plate having a hole diameter of 30 mm × 30 mm square.
[0029]
For the measurement, the radiant energy corresponding to the holes was measured with the temperature of the black body furnace set at 50 ° C., 79 ° C., and 118 ° C. The temperature of the stainless steel plate around the hole (background temperature) was kept at 24 ° C.
[0030]
Here, assuming that the measured temperature is T, the calculation formula of the radiant energy E at the pixel is as follows.
[0031]
E = 218000 / [{exp (1488.6 / (T + 273)}-1])
From the above equation, the radiant energy at T = 50 ° C. is E = 2194
The radiant energy at T = 79 ° C. is E = 3223
The radiant energy at T = 118 ° C. is E = 4952
And the radiant energy at a background temperature of 24 ° C. is E = 1461.
It is.
[0032]
However, actually, the radiant energy equivalent to one pixel measured three times is
T = 50 ° C. (E = 2194), 2018 (44.3 ° C.), 1979 (43.0 ° C.), 1991 (43.4 ° C.),
T = 79 ° C. (E = 3223), 2770 (67.0 ° C.), 2702 (65.1 ° C.), 1991 (63.0 ° C.),
At T = 118 ° C. (E = 4952), they are 4034 (98.4 ° C.), 3977 (97.1 ° C.), and 3946 (96.4 ° C.). Not shown.
[0033]
On the other hand, radiant energy using a stainless steel plate having a hole of 30 mm × 30 mm showed a measurement accuracy of 90% or more.
[0034]
When the radiant energy of a pixel in the vicinity of one pixel in the hole of 10 mm × 10 mm was examined, the measured value of the radiant energy at the background temperature was about 1550 to 1460 at 50 ° C., and the background radiant energy (E = 1461) ) Has a high radiant energy of about 0 to 90 at 79 ° C., the radiant energy range is about 1580 to 1460, and the radiant energy increases by about 0 to 120 with respect to the background radiant energy (E = 1461). It was found that the radiant energy range was about 1710 to 1460, which is about 0 to 250 higher than the background radiant energy (E = 1461).
[0035]
This means that even if the device under test falls within one pixel, that pixel is affected by the background temperature, and conversely, pixels near that one pixel are affected by the measured temperature of the pixel of the device under test. It is shown that.
[0036]
Therefore, the radiant energy of each pixel was measured by moving the stainless steel plate one pixel at a time around the pixel (5 × 5 pixels) in the vicinity of one pixel.
[0037]
FIG. 6 shows a sensing range model of 5 × 5 pixels 20 (however, pixels at the four corners of the 5 × 5 pixels are ignored because they are not affected, so that a total of 21 pixels).
[0038]
First, FIG. 6A shows the case where the hole is located at the center pixel 20a of the 5 × 5 pixels 20 and the temperature of the black body furnace is measured (condition 1). 6 (c), a hole is located at a pixel 20c which is obliquely shifted from the center pixel 20a by one neighborhood (condition 2). 3), FIG. 6D shows a case where a hole is located at a pixel 20d shifted by two neighborhoods up, down, left and right with respect to the center pixel 20a (condition 4), and FIG. 2 shows a case where a hole is located at a pixel 20e shifted by two neighborhoods (condition 5).
[0039]
In FIG. 6, each pixel displays A when the radiant energy A of the device under test is incident, displays B when the background energy B is incident, and assigns a coefficient a to the center pixel 20a and a center pixel 20a. 20a (coefficient a) is weighted by giving a coefficient b to the vicinity of the upper, lower, left and right 1, a coefficient c to the vicinity of the diagonal 1, a coefficient d to the vicinity of the upper, lower, left and right 2 and a coefficient e to the vicinity of the diagonal 2.
[0040]
Then, when the display energies P1 to P5 under the respective conditions 1 to 5 are set,
Condition 1: P1 = aA + 4bB + 4cB + 4dB + 8eB
Condition 2: P2 = aB + 3bB + 4cB + 4dB + 8eB + bA
Condition 3: P3 = aB + 4bB + 3cB + 4dB + 8eB + cA
Condition 4: P4 = aB + 4bB + 4cB + 3dB + 8eB + dA
Condition 5: P5 = aB + 4bB + 4cB + 4dB + 7eB + eA
It becomes.
[0041]
However, a + 4b + 4c + 4d + 8e = 1.
[0042]
Next, FIG. 7 is a diagram showing the range of the object to be measured in 5 × 5 pixels 20, and FIG. 7A shows the case where the object to be measured is in the range of 1 × 1 pixels. 7B shows a case where the object to be measured is in a range of 3 × 3 pixels, and FIG. 7C shows a case where the object to be measured is in a range of 5 × 5 pixels. .
[0043]
The true energy calculation formula for the 1 × 1 pixel in FIG.
A = (P-4bB-4cB-4dB-8eB) / a
It becomes.
[0044]
However, the coefficient e in the vicinity of the diagonal 2 is close to substantially zero, so that the calculation formula is simplified,
A = (P-4bB-4cB-4dB) / a
And
[0045]
In addition, when the radiant energy of the object to be measured is incident on the 3 × 3 pixels in FIG.
A = (P-4dB-8eB) / (a + 4b + 4c)
Similarly, since the coefficient e in the vicinity of the diagonal 2 is almost close to zero, to simplify the calculation formula,
A = (P−4 dB) / (a + 4b + 4c)
And
[0046]
Further, when the radiant energy of the object to be measured is incident on the 5 × 5 pixel in FIG.
A = P
Therefore, the correction formula becomes unnecessary.
[0047]
Next, the result of obtaining these coefficients a to d will be described with reference to FIG.
[0048]
8, as described with reference to FIGS. 4 and 6, the measured object temperature (black body temperature) is 50 ° C. (FIG. 8A), 79 ° C. (FIG. 8B), and 118 ° C. (FIG. 8). 3C shows the temperature of each pixel, the radiant energy of each pixel, and the average of the radiant energy of each neighboring pixel in the case of (c)).
[0049]
In FIGS. 8A to 8C, only one data is shown for each black body temperature for convenience of description, but the coefficients a to d, which are the correction formulas of the radiation thermometer, are more accurately determined. In order to obtain it, many temperatures are measured.
[0050]
Now, the display energy of the central pixel (coefficient a) is P1, the display energy value of the neighboring pixel is P2, the average display energy value of the pixel (coefficient b) near the top, bottom, left and right is P2, and the pixel near the diagonal one (coefficient c) is The average energy value of P3 and the average display energy value of the pixels (coefficient d) in the vicinity of the top, bottom, left and right are P4, and the display of each of P1 to P4 from the expressions of the above conditions 1 to 4 (coefficient e is zero) When the coefficients a to d are obtained by substituting the energy, the following are obtained.
[0051]

The following table shows the coefficients obtained when the measurement was performed three times.
[0052]

Table 2 shows the result of correcting the temperature using the coefficients of the overall average in Table 1 (a = 0.715803, b = 0.053578, c = 0.014790, d = 0.0026263).
[0053]

Table 3 shows the energy display.
[0054]

As described above, by correcting the temperature and the display energy of one pixel by using the coefficients a to d, the error rate can be kept within ± 5% with respect to the actual temperature and the radiant energy, and the reliability is higher. Temperature measurement can be performed.
[0055]
Next, an example of actually measuring the temperature of the compression connection pipe as an object for measuring the temperature will be described with reference to FIG.
[0056]
FIG. 1 shows an example in which the infrared radiation thermometer 10 measures the temperature of a retention clamp 54 of a steel tower 51 as a compression connection pipe.
[0057]
First, a distance L between the retention clamp 54 for performing temperature measurement and the radiation thermometer 10 is measured by a distance sensor (not shown), and a range in which the retention clamp 54 fits in the thermal image G captured by the radiation thermometer 10. S is set, and the radiation thermometer 10 is rolled around the optical axis by a rolling device 24 provided between the infrared radiation thermometer 10 and the tripod 22 so that the retention clamp 54 is horizontal. In a state where the pixel area 26 (5 × 5 pixels in the figure) corresponding to the temperature measurement part 25 is horizontal, the display energy of each pixel 20 is captured and stored.
[0058]
As described above, when the temperature data of the temperature measurement portion 25 of the retaining clamp 54 is captured, other portions are further measured.
[0059]
FIG. 2 is a block diagram of a temperature measurement device 30 that calculates a temperature measurement site 25 from a pixel area 26 measured by the radiation thermometer 10.
[0060]
The transmission line data 31 in which the temperature measurement device 30 stores, as a database, transmission line names, tower numbers, transmission line numbers, electric wire types, types of compression connection tubes, and numbers of the compression connection tubes for each transmission line. The type of the compression connection pipe and the number of the compression connection pipe are input from the transmission line data 31, data on the outer diameter of the electric wire and the diameter of the compression connection pipe are stored, and from the radiation thermometer 10 and the data input device 32 The compression connection pipe data 33 for storing the temperature data of the temperature measurement part 25 of the compression connection pipe, the coefficient data section 34 in which the data of the above-mentioned weighting coefficients a to d are stored, and the instant to determine the instantaneous viewing angle from the input measurement distance. The viewing angle indexing unit 35, the data and temperature data of the compression connection pipe from the compression connection pipe data 33, and the viewing angle from the instantaneous viewing angle calculation unit 35 and the coefficients a to d from the coefficient data unit 34. A temperature measurement calculation processing unit 36 for calculating the temperature of the compression connection pipe using the above-described correction formula; and a quality judgment unit 37 for determining the quality of the compression connection pipe from the temperature obtained by the temperature measurement calculation processing unit 36. The temperature data is stored in the data storage unit 38 and stored in the external data storage device 39, and is output from the data output unit 40 to the printer 41. These data are displayed on the display 42. I can do it.
[0061]
The data input device 32 receives the weather, air temperature (becomes a background temperature), wind direction, and wind speed at the time of measurement, and allows setting of the background temperature around the compression connection pipe. Current (current) that can be input.
[0062]
The temperature measuring device 30 uses the diameter of the compression connection pipe from the compression connection pipe data 33 and the instantaneous viewing angle θ from the instantaneous viewing angle indexing unit 35 to correct the temperature in the temperature measurement calculation processing unit 36. It is determined which region of the compression connection pipe is measured by the pixel region 26 measured by the total 10, and it is determined whether the calculation is performed using the above-described weighting coefficients a to d.
[0063]
Next, a correction equation for correcting the actual temperature of the compression connection pipe using the weighting coefficients a to d will be described.
[0064]
First, FIG. 6 is a conditional expression for obtaining the coefficients a to d, and FIG. 7 has been described in the pixel range where the energy of the DUT is 1 × 1, 3 × 3, and 5 × 5. However, the actual compression connection pipe is slender, and its width W falls within the range of 1 pixel, 3 pixels, and 5 pixels, but often includes 5 pixels in the length direction. In addition to the correction formulas for the pixel ranges of × 1, 3 × 3, and 5 × 5, a more accurate correction formula can be obtained by using a correction formula that takes into account the five pixels in the horizontal direction.
[0065]
This will be described with reference to FIG.
[0066]
As shown in FIG. 3A, when the 5 × 5 pixels 20 are all within the area of the compression connection pipe 44 and measure the temperature of the object to be measured, as shown in FIG. When the pixels 20d in the vicinity of 2 are protruding from the compression connection pipe 44 and partially measuring the background temperature (3 × 5 pixels), as shown in FIG. In the case where the pixel 20c of (a) partially measures the background temperature (1 × 5), the temperature of the compression connection pipe 44 and the background temperature are simultaneously measured at the central pixel 20a as shown in FIG. And sometimes.
[0067]
Therefore, first, when the 5 × 5 pixels 20 in FIG. 3A are all contained in the area of the compression connection pipe 44 and are measuring the temperature of the object to be measured, the temperature measurement calculation processing unit 36 sets the coefficient a The display energy of the pixel 20a is set to the measurement temperature (P = A) without using ず d.
[0068]
When the background temperature falls within one pixel 20a as shown in FIG. 3D, the measurement is not performed without calculation.
[0069]
When 3 × 5 pixels in FIG. 3B enter the area of the compression connection pipe 44,
The above 3 × 3 correction equation A = (P−4 dB−8 eB) / (a + 4b + 4c)
Medium, since the radiant energy A of the pixel measuring the temperature of the compression connection pipe is 3 × 5 = 15 pixels as shown in FIG.
A = (P-2bB-4cB-2dB-8eB) / (a + 4b + 4c + 4e)
Ask for.
[0070]
Next, in the case of one pixel of 1 × 5 in FIG. 3C, the above-described correction equation A = (P-4bB-4cB-4dB-8eB) / a
Medium, since the radiant energy A of the pixel measuring the temperature of the compression connection pipe is 1 × 5 = 5 pixels as shown in FIG.
A = (P-2bB-4cB-8eB) / (a + 2b + 2d)
Ask for.
[0071]
Here, A is the energy of the measured object, B is the background energy, and if the sky is reflected, the energy of the sky, and P is the energy displayed by the pixel 20a.
[0072]
When the width of the compression connection pipe continuously changes, the correction method is as follows: the width of the compression connection pipe is W, the size of one pixel is r, and the width W of the compression connection pipe is 1 pixel or more. When the range is smaller than the pixel,
A = (P-βB) / α
However,
α + β = 1
α = a + b (1 + W / r) + 2c (W / r−1) + 2d + 2e (W / r−1)
β = b (3-W / r) + 2c (3-W / r) + 2d + 2e (5-W / r)
Asking.
[0073]
When the width W of the compression connection pipe is in a range of 3 pixels or more and less than 5 pixels,
A = (P-βB) / α
However,
α + β = 1
α = a + 4b + 4c + d (W / r-1) + 2e (W / r-1)
β = d (5-W / r) + 2e (5-W / r)
Asking.
[0074]
As described above, even more accurate temperature measurement can be performed by selecting a correction formula depending on the extent to which the pixel can be photographed in the temperature measurement area based on the viewing angle θ.
[0075]
In the above description, conventionally, when measuring at a position close to the actual state of the compression connection pipe with a transmission line of a voltage class of 66 kV, 154 kV, 275 kV or more, the total number of equipment of the compression connection pipe that can be measured with 90% or more accuracy is considered. The ratio was 5.4% for 66 kV transmission lines, 5.0% for 154 kV transmission lines, and only about 26.0% for 275 kV or higher transmission lines. However, it is determined that the temperature of the compression connection pipe can be accurately measured at 99.1% for the 66 kV transmission line, 99.7% for the 154 kV transmission line, and 92.9% for the 275 kV or higher transmission line.
[0076]
In the above-described embodiment, the description has been made of the temperature measurement of the compression connection pipe. Of course, the present invention can also be applied to temperature measurement of an object.
[0077]
【The invention's effect】
In short, according to the present invention, it is possible to accurately measure the temperature of an object such as a compression connection pipe even from a long distance using a radiation thermometer.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention and showing a state in which a compression connection pipe is photographed by a radiation thermometer.
FIG. 2 is a block diagram of a temperature measuring device according to the present invention.
FIG. 3 is a diagram illustrating a pixel area of a radiation thermometer with respect to a compression connection pipe for measuring a temperature in the present invention.
FIG. 4 is an explanatory diagram of a blackbody furnace and a radiation thermometer for obtaining a correction equation in the present invention.
FIG. 5 is a diagram illustrating a viewing angle of a radiation thermometer in the present invention.
FIG. 6 is a diagram illustrating a relationship between radiant energy of 5 × 5 pixels and a coefficient for obtaining a correction equation in the present invention.
FIG. 7 is a diagram showing a relationship between a range of an object to be measured in 5 × 5 pixels and a correction formula in the present invention.
8 is a diagram showing the temperature and display energy of 5 × 5 pixels in the radiation thermometer when the temperature of the black body furnace is measured in the state of FIG.
FIG. 9 is a view showing a steel tower in which a compression connection pipe is used.
FIG. 10 is a diagram showing details of a compression connection pipe.
[Explanation of symbols]
10 Radiation thermometer 13 Black body furnace 20 Pixel 44 Compression connection pipe (object)
53 Retention clamp (compression connection pipe)
50 Transmission line 51 Steel tower

Claims

When measuring the temperature of an object such as a compression connection pipe or an electric wire of an overhead power transmission line using a radiation thermometer, an instantaneous viewing angle of one pixel of the radiation thermometer is obtained in advance, and the one pixel is known from a black body furnace or the like. The temperature of the DUT is detected, and a neighboring pixel adjacent to the one pixel is detected at a known background temperature, and the radiated energy of the DUT detected by the one pixel and the background radiant energy detected by each neighboring pixel are calculated. A correction formula is calculated in which the radiant energy of the DUT detected by one pixel becomes the radiant energy of the temperature of the DUT, and when the radiation thermometer measures the temperature of the compression connection pipe, the temperature is calculated based on the above correction formula. A temperature measuring method using a radiation thermometer, wherein the temperature is corrected.

The radiant energy obtained from the temperature of the device under test is A, the radiant energy obtained from the background temperature is B, and the weighting coefficient of the radiant energy P of one pixel at which the temperature of the device under test is detected is a. B, the weighting coefficient of the pixel in the vicinity of the diagonal 1 is c, the weighting coefficient of the pixel in the vicinity of the vertical and horizontal 2 is d, and the weighting coefficient of the pixel in the vicinity of the diagonal 2 is e. When calculating the formula based on the radiant energy of the pixel,
When the measured object is in the range of 1 × 1,
A = (P-4bB-4cB-4dB-8eB) / a
When the measured object is in the 3 × 3 range,
A = (P-4dB-8eB) / (a + 4b + 4c)
When the measured object is in the range of 5 × 5,
A = P
age,
The weighting coefficients a to e are obtained by inputting a known temperature from a black body furnace or the like to one pixel, inputting a known background temperature to a pixel in the vicinity thereof, and previously obtaining the temperature and the energy detected by each pixel. Item 4. A temperature measurement method using the radiation thermometer according to Item 1.

When the target object is slender such as a compression connection pipe or electric wire and the width is within the range of one pixel,
A = (P-2bB-4cB-2dB-8eB) / (a + 2b + 2d)
When the width of the object is in the range of 3 pixels,
A = (P-2dB-4eB) / (a + 4b + 4c + 2d + 4e)
When the width of the object is within the range of 5 pixels,
A = P
A temperature measuring method using the radiation thermometer according to claim 2, which is determined as follows.

When the width of the object is W and the size of one piece of one pixel is r, and the width W of the object is in a range of 1 pixel or more and less than 3 pixels,
A = (P-βB) / α
However,
α + β = 1,
α = a + b (1 + W / r) + 2c (W / r−1) + 2d + 2e (W / r−1),
β = b (3-W / r) + 2c (3-W / r) + 2d + 2e (5-W / r),
A temperature measuring method using the radiation thermometer according to claim 3, wherein the temperature is determined as:

When the width of the object is W and the size of one piece of one pixel is r, and the width W of the object is in a range of 3 pixels or more and less than 5 pixels,
A = (P-βB) / α
However,
α + β = 1,
α = a + 4b + 4c + d (W / r-1) + 2e (W / r-1)
β = d (5-W / r) + 2e (5-W / r)
A temperature measuring method using the radiation thermometer according to claim 3, wherein the temperature is determined as:

When taking a thermal image of an elongated object such as a compression connection pipe or an electric wire with the radiation thermometer, the radiation thermometer is rolled so that the elongated object is horizontal to the thermal image, and the image is taken. A temperature measurement method using the radiation thermometer according to any one of 1 to 5.