JP4591899B2

JP4591899B2 - Life diagnosis method for oil-filled electrical equipment

Info

Publication number: JP4591899B2
Application number: JP2000021863A
Authority: JP
Inventors: 武司張替; 正美片山; 敏夫鈴木; 敏次石井
Original assignee: ユカインダストリーズ株式会社
Priority date: 2000-01-26
Filing date: 2000-01-26
Publication date: 2010-12-01
Anticipated expiration: 2020-01-26
Also published as: JP2001210538A

Description

【０００１】
【発明の属する技術分野】
本発明は、油入電気機器の寿命診断方法、特に油入変圧器、油入リアクトル等の油入電気機器の寿命を診断する方法に関するものである。
【０００２】
【従来の技術】
油入変圧器、油入リアクトル等の油入電気機器の寿命は、巻線に巻かれている絶縁紙の最高温度部の劣化の程度に左右されるといわれている。絶縁紙の主要成分は、セルロース化合物であり、通常、下記の式で示される。
【０００３】
【式１】

セルロース化合物は、グルコース環が連結したものであり、分子中に水酸基を有することから、油入電気機器の長期間の使用条件下においては、熱分解、酸化および加水分解等によりアルコール、アルデヒド、有機酸等の生成およびグルコース結合の切断、グルコース環の開環等により二酸化炭素および一酸化炭素（以下、必要に応じ「CO₂＋CO」という。）等の各種劣化物の生成が知られている。このようなセルロース化合物の分解反応により、当初約８００〜約１２００の絶縁紙の平均重合度が２００程度にまで低下することが観察されている。この絶縁紙の劣化の程度は、絶縁紙自体の引張強さ、平均重合度などの測定により診断される。しかし、運転中の油入電気機器から絶縁紙を採取することができないため、一般に絶縁紙の引張強さや平均重合度と密接な関係がある絶縁油中に生成する前記 CO₂＋CO、フルフラール、アセトンなどの絶縁紙劣化指標成分の含有量を測定して、絶縁紙の劣化、寿命診断が行なわれている。
【０００４】
従来、油入電気機器の寿命診断方法としては、実験結果または実器の解体調査結果から得られた絶縁油中の絶縁紙劣化指標成分量と絶縁紙平均重合度との関係を用いて、測定した絶縁紙劣化指標成分量を平均重合度または平均重合度残率に換算し、その値を次に示す Ackerの式（IEEE, PES WINTER MEETING A76 021-6(1976)参照）などの劣化特性式に代入して寿命を推定している。
Ｌ_R ＝Ｌ_O （１−ｒ）ⁿ
Ackerの式は、油入電気機器の絶縁材料の劣化速度が温度の他に反応物質の濃度によっても影響されることを前提に油入電気機器の残存寿命Ｌ_R と初期寿命Ｌ_O との関係を上記のように表わしたものである。式中ｒは寿命劣化率であり、ｎは時間である。余寿命を推定するには、Ｌ_O を平均重合度の初期値とし、一定期間運転後の絶縁紙平均重合度Ｌ_R は CO₂＋CO量等から推定する。前記式のＬ_O 、Ｌ_R 、ｎに当該油入電気機器の具体的な数値を代入すればｒを算出することができ、Ｌ_O とｒを定数とすれば、Ｌ_R をｎの関数とすることにより寿命曲線を得ることができる。
【０００５】
【発明が解決しようとする課題】
しかしながら、上述したような油入電気機器の寿命診断方法では、測定した絶縁紙劣化指標成分量を絶縁紙平均重合度または平均重合度残率に換算する必要があり、この換算に必要な実験結果または実器の解体調査結果から得られた両者の関係の幅が大きく、換算式の精度が十分でないという問題点があった。
【０００６】
また、 Ackerの式などの劣化特性式も油入電気機器の寿命診断における有効性が未だ検証されていないという問題点があった。
従って、本発明の課題は、このような問題点を解決し、簡便で、かつ精度の高い油入電気機器の寿命診断方法を提供することにある。
【０００７】
【課題を解決するための手段】
そこで、本発明者らは、前記の本発明の課題を解決するため、鋭意検討を重ねたところ、油入電気機器の実器の解体調査結果から得られた絶縁紙劣化指標成分量と絶縁紙平均重合度４５０以下との関係に確率の考え方を導入することにより、従来から行なわれている絶縁紙劣化指標成分量の平均重合度および平均重合度残率への換算をしなくとも油入電気機器の寿命の診断可能な方法に想到し、これらの知見に基づいて本発明の完成に到達した。
【０００８】
すなわち、本発明は、油入電気機器の余寿命を絶縁油中に生成した絶縁紙劣化指標成分量から推定する油入電気機器の寿命診断方法であって、
１）前記油入電気機器から採取した絶縁油中の絶縁紙劣化指標成分量を測定し、
２）前記１）で得られた絶縁紙劣化指標成分量の測定値から、下記のステップ▲１▼および▲２▼を経て作成された関係図IIを用いて、当該油入電気機器が、絶縁紙平均重合度４５０以下である油入電気機器に属する確率（以下、本明細書において必要に応じ、「絶縁紙平均重合度４５０以下である確率」という。）を求め、
ステップ▲１▼：統計的解析の可能な台数の油入電気機器から収集した過去の解析結果に基づいて絶縁紙劣化指標成分量と絶縁紙平均重合度との関係図Ｉを作成し、
ステップ▲２▼：関係図Ｉに基づいて絶縁紙劣化指標成分量と絶縁紙平均重合度４５０以下である油入電気機器に属する油入電気機器の確率０％〜１００％との対応関係を示す関係図IIを作成する。
３）前記２）で得られた当該油入電気機器の前記確率および当該油入電気機器の現在まで経時的に測定された絶縁紙劣化指標成分量から求めた確率と対応する運転時間とに基づいて作成された関係図III を用いて当該油入電気機器の余寿命を推定する
ことを特徴とする油入電気機器の寿命診断方法に関するものである。
【０００９】
【発明の実施の形態】
以下、本発明について詳細に説明する。
本発明の油入電気機器の寿命診断方法に適用される油入電気機器は、コイル等の巻線部に絶縁紙が使用され、かつ絶縁油中に浸漬される構造のものであり、具体的には、油入変圧器、油入リアクトル等を挙げることができる。また、これらの電気機器については、完全密閉型および開放型のいずれにも適用することができる。
【００１０】
油入電気機器に用いられる絶縁油としては、鉱油または合成油を挙げることができる。鉱油は、沸点約２５０℃〜約４００℃の炭化水素油であり、ナフテン系炭化水素、パラフィン系炭化水素および芳香族系炭化水素等から構成されている。炭化水素油としては、通常、水素化精製等により硫黄化合物、窒素化合物、酸素化合物および不飽和成分等の不純物を除去したものが用いられるが、電気的性質および熱・酸化安定性の観点から両者を満足させる適度の精製が行なわれ、硫黄化合物、窒素化合物等の熱・酸化安定性に対する有効成分の含有量が制御されている。合成油としてはアルキルベンゼン、シリコーン油等が挙げられる。さらに、これらの鉱油および合成油の混合物およびこれらを基油としベンゾトリアゾール等の添加剤を加えたものも使用することができる。
【００１１】
絶縁紙の主たる構成材料は、セルロース化合物からなり、前記構造式を有するものを用いることができる。絶縁紙の平均重合度として１０００〜１２００のもの、すなわち、前記セルロース化合物の式中、ｎが１０００〜１２００のものが有用である。絶縁紙は、長期間にわたって使用することが可能であるが、その長期間の使用により主成分のセルロース化合物の分解、酸化等により劣化し機械的強度、平均重合度が低下する。従って、本発明の油入電気機器の寿命診断方法においては、このような現象に着目し、平均重合度４５０以下を絶縁紙の寿命に達した段階とした。絶縁紙の寿命は、絶縁紙の引張強さ等の機械的強度に依存し、その引張強さは平均重合度と密接な関係にあることが従来の実測データに基づいて検証されているので平均重合度を絶縁紙の寿命診断の指標として利用することができる。
【００１２】
次に、本発明の油入電気機器の寿命診断方法について具体的に説明すると、絶縁紙劣化指標成分量の測定結果に基づいて、絶縁紙平均重合度４５０以下である確率を求め、その推移により油入電気機器の余寿命を推定することからなるものであり、下記の三段階の工程から構成される。
【００１３】
第一工程絶縁油試料を採取し絶縁紙劣化指標成分量を測定する。
第二工程絶縁紙劣化指標成分量の測定値から、前記ステップ▲１▼および▲２▼を経て前記関係図Ｉから誘導された関係図IIを用いて、該絶縁紙劣化指標成分量に対応する絶縁紙平均重合度４５０以下である確率を求める。
第三工程第二工程で得られた現在の絶縁紙平均重合度４５０以下である確率および当該油入電気機器について現在まで経時的に測定された絶縁紙劣化指標成分量から求めた絶縁紙平均重合度４５０以下である確率と運転時間との関係図III を作成し、該確率の推移により油入電気機器の余寿命を推定する。
【００１４】
図１において第一の工程が（１）および（２）からなり、第二の工程および第三の工程がそれぞれ（３）および（４）である。図中、（ａ）および（ｂ）は、第一の工程を機能させるために提供される情報であり、（ａ）は関係図Ｉ、（ｂ）は関係図IIを示す。また、（ｃ）は工程（４）のために提供される情報であり、関係図III を示す。各工程についてさらに具体的に説明する。
【００１５】
第一の工程は、
運転中の油入電気機器から採取した絶縁油中の絶縁紙劣化指標成分量を測定することを内容とする。絶縁紙劣化指標成分としては、 CO₂＋CO、フルフラールまたはアセトンを挙げることができ、いずれの成分も本発明の油入電気機器の寿命診断方法に用いることができる。絶縁油中に生成した絶縁紙劣化指標成分量の測定方法は特に限定されるものではなく各種の測定方法を利用することができるが、 CO₂＋COの含有量の測定方法は、石油学会規格ＪＰＩ−５Ｒ−５１−９８「油入電気機器からのガス及び絶縁油の採取と遊離及び溶存ガス分析方法」を利用することが好ましい。具体的には、絶縁油に溶解しているガスを抽出し、その抽出ガスをガスクロマトグラフを使用して分析する。分析に際しては油中ガスの抽出装置、抽出方法、抽出手段その他、測定条件は当該規格に従うこととし、また油中ガス濃度を正確に求めるには検量線が用いられる。このようにして、絶縁紙単位重量当たりの CO₂＋CO量（ml/g）を算出することができる。
【００１６】
また、絶縁油中に含有されるフルフラール量は、石油学会規格ＪＰＩ−５Ｓ−５８−９９「電気絶縁油フルフラールの定量試験方法」（１９９９）により、アセトン量は、電気協同研究第５４巻第５号（その１）「油入変圧器の保守管理」（１９９９）により測定することができる。
【００１７】
第二の工程において、
先ず、関係図Ｉを作成する。関係図Ｉは、統計的解析が可能な台数の油入電気機器から収集した過去の解析結果に基づいて作成した絶縁紙劣化指標成分量と絶縁紙平均重合度との関係を示すものである。統計的解析が可能な台数は、限定するものではないが、例えば、約６０台以上であれば好ましい。
【００１８】
関係図Ｉの具体例として図２が示される。図２は、油入電気機器、具体的には９０台以上の変圧器、リアクトル等の解体による経年劣化度の調査により得られた絶縁紙劣化指標成分量と対応する絶縁紙平均重合度の各測定値を収集し、全測定値数の約９０％以上が含まれるように、該測定値を用いて下限範囲ラインと上限範囲ラインを設定することにより定まる絶縁紙劣化指標成分量と絶縁紙平均重合度との関係を図示したものである。
【００１９】
図２は、絶縁紙劣化指標成分として CO₂＋COを利用した具体例を示すものであり、絶縁油中の CO₂＋CO量と絶縁紙平均重合度との関係は、下限範囲ライン２および上限範囲ライン１を設定することにより図示されている。この場合、下限範囲ライン２と上限範囲ライン１との間の巾は、実測値の分布の状況により決定される。
【００２０】
図２についてさらに詳細に説明すると、Ａ点は、絶縁紙平均重合度４５０ライン３と下限範囲ライン２と、さらに CO₂＋CO量ライン４とが交叉する点であり、ＡＡ’間が０％を示すことから、▲１▼ CO₂＋CO量が 0.2ml／g のとき、▲２▼絶縁紙平均重合度４５０以下である確率が０％であることを示す。
【００２１】
ｂ点は、絶縁紙平均重合度４５０ライン３と CO₂＋CO量ライン５とが交叉する点であり、巾ＢＢ’間のうちＢｂ間が２５％となった点を示すことから、▲１▼ CO₂＋CO量が0.37ml／g のとき、▲２▼絶縁紙平均重合度４５０以下である確率が２５％であることを示す。
【００２２】
また、ｃ点は、絶縁紙平均重合度４５０ライン３と CO₂＋CO量ライン６とが交叉する点であり、ＣＣ’間のうちＣｃ間が５０％の点を示すことから、▲１▼ CO₂＋CO量が0.67ml／g のとき、▲２▼絶縁紙平均重合度４５０以下である確率が５０％であることを示す。
【００２３】
ｄ点は、絶縁紙平均重合度４５０ライン３と CO₂＋CO量ライン７とが交叉する点であり、ＤＤ’間のうちＤｄ間が７５％の点を示すことから、▲１▼ CO₂＋CO量が 1.2ml／g のとき、▲２▼絶縁紙平均重合度４５０以下である確率が７５％であることを示す。
【００２４】
さらに、Ｅ’点は、絶縁紙平均重合度４５０ライン３と上限範囲ライン１と交叉する点であり、ＥＥ’間が１００％を示すことから、▲１▼ CO₂＋CO量が 2.0ml／g のとき、▲２▼絶縁紙平均重合度４５０以下である確率が１００％であることを示す。
【００２５】
以上説明したように、図２の事例は、実器の解体調査により得られた実測値を用いた CO₂＋CO量に対する絶縁紙平均重合度との関係において、下限範囲ライン２と交叉するＡ点の CO₂＋CO量が 0.2ml／g 、絶縁紙平均重合度４５０以下である確率が０％であり、一方、上限範囲ライン１と交叉するＥ’点の CO₂＋CO量が 2.0ml／g で絶縁紙平均重合度４５０以下である確率が１００％であることを示すものである。このように、 CO₂＋CO量が 0.2ml／g 〜 2.0ml／g においては絶縁紙平均重合度４５０以下である確率が０％〜１００％であり、この範囲を要注意レベルの範囲とされ、確率１００％において危険レベルに達したものと判断される。
【００２６】
次に、関係図Ｉに基づいて関係図IIを作成する。
関係図IIは、絶縁紙劣化指標成分量と絶縁紙平均重合度４５０以下である確率との関係を示す。関係図IIの具体例として図３を挙げる。図３は、図２で示す CO₂＋CO量と絶縁紙平均重合度との関係から誘導されたものであり、 CO₂＋CO量に対する絶縁紙平均重合度４５０以下である確率０％〜１００％の関係を示すものである。
【００２７】
従って、絶縁油中の CO₂＋CO量の測定値を得ることができれば、図３を用いることにより絶縁紙平均重合度４５０以下である確率を求めることができる。例えば、変圧器絶縁油中の CO₂＋CO量を測定し、絶縁紙単位重量当たりの CO₂＋CO量が 0.4ml／g である場合、絶縁紙平均重合度４５０以下である確率約２６％が得られる。
【００２８】
本発明の油入電気機器の寿命診断方法における第三の工程は、前記第二の工程において得られた現在の絶縁紙平均重合度４５０以下である確率および現在までに経時的に測定された絶縁紙劣化指標成分量から求めた絶縁紙平均重合度４５０以下である確率と運転時間との関係を示す油入電気機器毎の関係図III(寿命曲線）を作成し、これを用いて当該油入電気機器の余寿命を推定することを内容とする。
【００２９】
具体的に説明すると図４は、関係図III を例示したものであり、絶縁油中の CO₂＋CO量の経年の測定結果（●印）と現在の測定結果（○印）をプロットすることにより得られた寿命曲線を示すものである。寿命曲線は、通常、運転条件等の違いにより油入電気機器毎に絶縁紙平均重合度４５０以下である確率１００％に到達する時間が異なっている。また、寿命点については油入電気機器の特性等を考慮して絶縁紙平均重合度４５０以下である確率を１００％、９０％、８０％など任意に設定することが可能である。図４には、曲線▲１▼で示す運転時間５年、１０年および１５年で絶縁紙平均重合度４５０以下である確率がそれぞれ２１％、５０％および６８％の変圧器、曲線▲２▼で示す運転時間１０年、２０年および３０年で絶縁紙平均重合度４５０以下である確率がそれぞれ２１％、５０％および６８％の変圧器の寿命曲線が示されている。
【００３０】
また、過去における経年の CO₂＋CO量の測定結果が存在せず、初めて測定した場合、寿命曲線は、 CO₂＋CO量が運転開始から現在まで一定速度で増加したとして作成し、次回の測定結果の加入により寿命曲線を修正すればよい。
【００３１】
前記の寿命曲線の説明において、曲線▲１▼の変圧器の場合、運転時間１５年における余寿命は、寿命点を絶縁紙平均重合度４５０以下である確率１００％とすると１５年、７５％とすると２年を得ることができる。
【００３２】
また、曲線▲２▼の変圧器の場合、運転時間３０年における余寿命は、寿命点を絶縁紙平均重合度４５０以下である確率１００％とすると３０年、７５％とすると６年を得ることができる。
【００３３】
このようにして、油入電気機器の絶縁油中の絶縁紙劣化指標成分量の測定値から、絶縁紙平均重合度への換算を要することなく、絶縁紙平均重合度４５０以下である確率をもって余寿命を推定することができる。
【００３４】
従って、本発明によれば、
絶縁油中の絶縁紙劣化指標成分量から前記の工程を経ることにより絶縁紙平均重合度４５０以下である確率を求め、その確率の推移により油入電気機器の寿命を推定する方法を提供するものである。
【００３５】
【実施例】
次に、実施例および比較例により本発明をさらに具体的に説明する。もっとも本発明は、実施例等により何ら限定されるものではない。なお、実施例等で利用した測定方法は次の通りである。
【００３６】
（１）CO₂ ＋CO量
石油学会規格ＪＰＩ−５Ｒ−５１−９８「油入電気機器からのガス及び絶縁油の採取と遊離及び溶存ガス分析方法」（１９９８）による。
（２）絶縁紙平均重合度
日本電機工業会規格ＪＥＭ１４５５「変圧器用絶縁紙の平均重合度測定方法」（１９９１）による。
【００３７】
実施例１
CO ₂ ＋ CO 量の測定
変圧器Ａ（運転時間２０年）から絶縁油を採取し、前記石油学会規格ＪＰＩ−５Ｒ−５１−９８の方法により CO₂＋CO量を測定し、絶縁紙１ｇ当たり0.92mlの結果を得た。
【００３８】
絶縁紙平均重合度４５０以下である確率の算出
図３を用いて CO₂＋CO量0.92ml／g から絶縁紙平均重合度４５０以下である確率を求めたところ６５％であった。
【００３９】
ここで用いた図２および図３は次のようにして作成した。
図２は、絶縁紙劣化指標成分として CO₂＋COを用いた場合について、その生成量と絶縁紙平均重合度との関係を示しており、電気協同研究第５４巻第５号（その１）から引用した。図中の２本の曲線は９９台の変圧器、リアクトル等の実器の解体調査結果から得られた範囲を示しており、絶縁紙平均重合度４５０に対する CO₂＋CO量は 0.2ml／g 〜2.0 ml／g となり、この濃度範囲を要注意レベルとした。なお、0.2 ml／g 以下は絶縁紙平均重合度４５０以下である確率が０％、2.0 ml／g 以上は１００％である。絶縁紙平均重合度４５０以下である確率の設定は、要注意レベルについて行ない、図中には例として確率２５％、５０％、７５％の場合について直線（実線）で示した。
【００４０】
図３は、絶縁紙劣化指標成分として CO₂＋COを用いた場合について、図２の要注意レベルにおける CO₂＋CO量と絶縁紙平均重合度４５０以下である確率０％〜１００％との関係をプロットしたものである。この関係を用いて CO₂＋CO量から絶縁紙平均重合度４５０以下である確率を求めた。
【００４１】
余寿命の推定
変圧器Ａの過去の経時的に測定した CO₂＋CO量をプロット（●印）した図５に、今回運転時間２０年で絶縁紙平均重合度４５０以下である確率の評価結果を追加プロット（○印）し、寿命曲線を作成した。
この寿命曲線から変圧器Ａについて同一負荷条件では余寿命は確率１００％の場合２６年、確率９０％の場合は１６年となり、確率８０％では８年の結果を得た。
【００４２】
実施例２
変圧器Ｂについて２０年間運転した時点で初めて CO₂＋CO量を測定したところ0.60ml/gであった。この測定結果から図３を用いて、絶縁紙平均重合度４５０以下である確率４６％の結果を得た。この結果に基づき図６に示す変圧器Ｂの寿命曲線を作成した。なお、変圧器Ｂの寿命曲線は、過去データのない場合であり、 CO₂＋CO量が運転開始から現在まで一定速度で増加したとして作成した。
この結果、変圧器Ｂについて、同一負荷条件では余寿命は確率８０％の場合２３年、確率８６％以上で３０年以上の結果を得た。
【００４３】
実施例３〜６
変圧器Ｃ〜Ｆについて、それぞれ、絶縁油試料を採取し、 CO₂＋CO量を測定して、表１に示す結果を得た。これらの結果から、図３を用いて絶縁紙平均重合度４５０以下である確率を求めた。この確率の値を過去の経時的に測定して得られた集積値に追加することにより各変圧器の寿命曲線を作成し、これに基づいて確率８０％を寿命点とした場合の余寿命を推定した。各結果を表１に示す。
【００４４】
【表１】

【００４５】
比較例１
実施例１で測定した変圧器Ａの CO₂＋CO量（0.92ml/g）を用いて、従来の方法により余寿命を推定した。図２から、 CO₂＋CO量0.92ml/gに対する絶縁紙平均重合度は２６３〜５５５であり、中央値は４０９となる。寿命点を絶縁紙平均重合度４５０とすると、変圧器Ａはすでに寿命に達していることになる。
【００４６】
比較例２
実施例２で測定した変圧器Ｂの CO₂＋CO量（0.60ml/g）を用いて、従来の方法により余寿命を推定した。図２から、 CO₂＋CO量0.60ml/gに対する絶縁紙平均重合度は３０５〜６２１であり、中央値は４６３となる。寿命点を絶縁紙平均重合度４５０、Ｌ_O ＝１０００として Ackerの式を用いて変圧器Ｂの余寿命を推定すると１年となる。
【００４７】
実施例および比較例から、従来の寿命診断方法によれば、絶縁紙劣化指標成分量の絶縁紙平均重合度への換算にはかなりばらつきが大きく、精度のよい推定ができないことがわかる。
【００４８】
【発明の効果】
以上説明したように、本発明の油入電気機器の寿命診断方法によれば、従来の方法による絶縁紙劣化指標成分量から絶縁紙平均重合度への換算を必要とすることなく、絶縁紙平均重合度４５０以下である確率を求め、この確率の推移により寿命曲線を作成し余寿命を推定することができるので、簡便でありかつ寿命診断の精度が向上するという効果がある。
【図面の簡単な説明】
【図１】本発明の油入電気機器の寿命診断方法のフローチャートである。
【図２】変圧器、リアクトル等の実器の解体調査結果の CO₂＋COについて、 CO₂＋CO量と絶縁紙平均重合度との関係を示すグラフである。
【図３】図２から求めた CO₂＋CO量と絶縁紙平均重合度４５０以下である確率との関係を示すグラフである。
【図４】絶縁紙平均重合度４５０以下である確率の推移で表わした寿命曲線である。
【図５】実施例１の変圧器Ａについて、絶縁紙平均重合度４５０以下である確率の推移で表した寿命曲線である。
【図６】実施例２の変圧器Ｂについて、絶縁紙平均重合度４５０以下である確率の推移で表した寿命曲線である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a life diagnosis method for oil-filled electrical equipment, and more particularly to a method for diagnosing the life of oil-filled electrical equipment such as oil-filled transformers and oil-filled reactors.
[0002]
[Prior art]
The life of oil-filled electrical equipment such as oil-filled transformers and oil-filled reactors is said to depend on the degree of deterioration of the highest temperature part of the insulating paper wound around the winding. The main component of the insulating paper is a cellulose compound, and is usually represented by the following formula.
[0003]
[Formula 1]

Cellulose compounds are linked with a glucose ring and have a hydroxyl group in the molecule. Under the long-term use conditions of oil-filled electrical equipment, cellulose compounds, alcohols, aldehydes, organics are decomposed by thermal decomposition, oxidation, hydrolysis, etc. It is known that various degraded products such as carbon dioxide and carbon monoxide (hereinafter referred to as “CO ₂ + CO” as necessary) are produced by the production of an acid and the like, the cleavage of a glucose bond, the opening of a glucose ring, and the like. It has been observed that the average polymerization degree of insulating paper of about 800 to about 1200 is reduced to about 200 by the decomposition reaction of the cellulose compound. The degree of deterioration of the insulating paper is diagnosed by measuring the tensile strength, average polymerization degree, etc. of the insulating paper itself. However, since insulating paper cannot be collected from oil-filled electrical equipment during operation, the CO ₂ + CO, furfural, and acetone produced in insulating oil, which are generally closely related to the tensile strength and average degree of polymerization of insulating paper, are not available. Insulation paper deterioration index component content such as insulation paper is measured for deterioration and life diagnosis of insulation paper.
[0004]
Conventionally, as a life diagnosis method for oil-filled electrical equipment, measurement was performed using the relationship between the amount of insulation paper deterioration index component in insulating oil and the average degree of polymerization of insulating paper obtained from experimental results or results of dismantling investigation of actual equipment. The insulation paper deterioration index component amount is converted into the average polymerization degree or average polymerization degree residual ratio, and the value is used as the deterioration characteristic equation such as Acker's equation (IEEE, PES WINTER MEETING A76 021-6 (1976)) The lifetime is estimated by substituting into.
L _R = L _O (1-r) ⁿ
Acker's equation is the relationship between the remaining life L _R and the initial life L _O of the oil-filled electrical equipment on the assumption that the degradation rate of the insulation material of the oil-filled electrical equipment is also affected by the concentration of the reactants in addition to the temperature. Is expressed as described above. In the formula, r is a lifetime deterioration rate, and n is time. In order to estimate the remaining life, L _O is used as an initial value of the average polymerization degree, and the average polymerization degree L _R of insulating paper after a certain period of operation is estimated from the amount of CO ₂ + CO. _R can be calculated by substituting specific numerical values of the oil-filled electrical equipment for L _O , L _R , and n in the above formula, and if L _O and r are constants, L _R is a function of n. By doing so, a life curve can be obtained.
[0005]
[Problems to be solved by the invention]
However, in the life diagnosis method for oil-filled electrical equipment as described above, it is necessary to convert the measured insulation paper deterioration index component amount into the insulation paper average polymerization degree or average polymerization degree residual rate, and the experimental results necessary for this conversion Or, there was a problem that the range of the relationship between the two obtained from the dismantling investigation result of the actual device was large and the accuracy of the conversion formula was not sufficient.
[0006]
In addition, degradation characteristic formulas such as Acker's formula have not yet been validated in the life diagnosis of oil-filled electrical equipment.
Accordingly, an object of the present invention is to provide a life diagnosis method for oil-filled electrical equipment that solves such problems and is simple and highly accurate.
[0007]
[Means for Solving the Problems]
Therefore, the inventors of the present invention have made extensive studies to solve the above-described problems of the present invention. As a result, the insulation paper deterioration index component amount and the insulation paper obtained from the result of dismantling investigation of the actual equipment of the oil-filled electrical equipment By introducing the concept of probability into the relationship with the average degree of polymerization of 450 or less, oil-filled electricity can be used without converting the insulation paper deterioration index component amount into the average degree of polymerization and the average degree of polymerization residual rate, which has been conventionally performed. The inventors have conceived a method capable of diagnosing the lifetime of the device, and have completed the present invention based on these findings.
[0008]
That is, the present invention is a method of diagnosing the life of an oil-filled electrical device that estimates the remaining life of the oil-filled electrical device from the amount of insulation paper deterioration index component generated in the insulating oil,
1) Measure the amount of insulation paper deterioration index component in the insulation oil collected from the oil-filled electrical equipment,
2) From the measured value of the insulation paper deterioration index component amount obtained in 1) above, the oil-filled electrical equipment is insulated using the relationship diagram II created through the following steps (1) and (2). Probability of belonging to oil-filled electrical equipment having an average degree of polymerization of paper of 450 or less (hereinafter referred to as “probability of having an average degree of polymerization of insulating paper of 450 or less” in this specification, if necessary),
Step (1): Based on past analysis results collected from the number of oil-filled electrical devices capable of statistical analysis, create a relationship diagram I between the amount of insulation paper deterioration index component and the average degree of polymerization of the insulation paper,
Step (2): Based on the relationship diagram I, shows the correspondence between the insulation paper deterioration index component amount and the probability of oil-filled electrical equipment belonging to oil-filled electrical equipment having an insulation paper average polymerization degree of 450 or less of 0% to 100%. Create Relationship Diagram II.
3) Based on the probability of the oil-filled electrical device obtained in 2) above and the probability obtained from the amount of insulating paper deterioration index component measured over time of the oil-filled electrical device and the corresponding operation time. The present invention relates to a method for diagnosing the life of oil-filled electrical equipment, characterized in that the remaining life of the oil-filled electrical equipment is estimated using the relationship diagram III created in the above.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The oil-filled electrical equipment applied to the life diagnosis method for oil-filled electrical equipment of the present invention has a structure in which insulating paper is used for a winding portion of a coil or the like and is immersed in insulating oil. Examples thereof include an oil-filled transformer and an oil-filled reactor. In addition, these electrical devices can be applied to both a completely sealed type and an open type.
[0010]
Examples of the insulating oil used in the oil-filled electrical device include mineral oil and synthetic oil. Mineral oil is a hydrocarbon oil having a boiling point of about 250 ° C. to about 400 ° C., and is composed of naphthenic hydrocarbons, paraffinic hydrocarbons, aromatic hydrocarbons, and the like. Hydrocarbon oils are usually those from which impurities such as sulfur compounds, nitrogen compounds, oxygen compounds and unsaturated components have been removed by hydrorefining, etc., both of which are from the viewpoint of electrical properties and thermal / oxidative stability. Therefore, the content of the active ingredient with respect to the thermal / oxidative stability of sulfur compounds, nitrogen compounds and the like is controlled. Synthetic oils include alkylbenzene and silicone oil. Further, a mixture of these mineral oils and synthetic oils and those obtained by adding these to the base oil and additives such as benzotriazole can also be used.
[0011]
The main constituent material of the insulating paper is made of a cellulose compound, and those having the above structural formula can be used. Insulating paper having an average degree of polymerization of 1000 to 1200, that is, n of 1000 to 1200 in the formula of the cellulose compound is useful. Insulating paper can be used over a long period of time, but its long-term use degrades due to decomposition, oxidation, etc. of the main component cellulose compound, and mechanical strength and average degree of polymerization decrease. Therefore, in the method for diagnosing the life of oil-filled electrical equipment according to the present invention, paying attention to such a phenomenon, the average degree of polymerization of 450 or less is set to the stage where the life of the insulating paper has been reached. The life of the insulation paper depends on the mechanical strength such as the tensile strength of the insulation paper, and it is verified that the tensile strength is closely related to the average degree of polymerization based on the conventional measurement data. The degree of polymerization can be used as an index for life diagnosis of insulating paper.
[0012]
Next, the life diagnosis method for oil-filled electrical equipment according to the present invention will be described in detail. Based on the measurement result of the insulating paper deterioration index component amount, the probability that the average degree of polymerization of insulating paper is 450 or less is obtained, and the transition It consists of estimating the remaining life of oil-filled electrical equipment, and consists of the following three steps.
[0013]
First step Insulating oil sample is taken and the amount of insulating paper deterioration index component is measured.
Second Step Corresponding to the insulating paper deterioration index component amount from the measured value of the insulating paper deterioration index component amount, using the relationship diagram II derived from the relationship diagram I through the steps (1) and (2). The probability that the insulation paper average polymerization degree is 450 or less is obtained.
Third step Insulating paper average polymerization obtained from the probability of the present insulating paper average polymerization degree of 450 or less obtained in the second step and the amount of the insulating paper deterioration index component measured over time for the oil-filled electrical device to date A relationship diagram III between the probability of the degree of 450 or less and the operation time is created, and the remaining life of the oil-filled electrical device is estimated from the transition of the probability.
[0014]
In FIG. 1, a 1st process consists of (1) and (2), and a 2nd process and a 3rd process are (3) and (4), respectively. In the figure, (a) and (b) are information provided to make the first step function, (a) shows a relationship diagram I, and (b) shows a relationship diagram II. Further, (c) is information provided for the step (4) and shows a relation diagram III. Each step will be described more specifically.
[0015]
The first step is
The content is to measure the amount of insulation paper deterioration index component in insulating oil collected from oil-filled electrical equipment during operation. Examples of the insulating paper deterioration index component include CO ₂ + CO, furfural or acetone, and any of these components can be used in the life diagnosis method for oil-filled electrical equipment of the present invention. The measurement method of the amount of insulation paper deterioration index component generated in the insulating oil is not particularly limited, and various measurement methods can be used, but the measurement method of the content of CO ₂ + CO is JPI standard JPI. It is preferable to use -5R-51-98 “Gas and insulating oil collection from oil-filled electrical equipment and analysis method for free and dissolved gas”. Specifically, a gas dissolved in the insulating oil is extracted, and the extracted gas is analyzed using a gas chromatograph. In the analysis, the oil gas extraction device, the extraction method, the extraction means, and other measurement conditions follow the standard, and a calibration curve is used to accurately determine the oil gas concentration. In this way, the amount of CO ₂ + CO per unit weight of insulating paper (ml / g) can be calculated.
[0016]
In addition, the amount of furfural contained in the insulating oil is determined according to the Japan Petroleum Institute Standard JPI-5S-58-99 “Quantitative test method for electric insulating oil furfural” (1999). (Part 1) “Maintenance and management of oil-filled transformers” (1999).
[0017]
In the second step,
First, the relationship diagram I is created. The relationship diagram I shows the relationship between the insulating paper deterioration index component amount and the insulating paper average polymerization degree created based on the past analysis results collected from the number of oil-filled electrical devices capable of statistical analysis. The number of units that can be statistically analyzed is not limited, but is preferably about 60 units or more, for example.
[0018]
As a specific example of the relationship diagram I, FIG. 2 is shown. FIG. 2 shows each of the insulation paper average polymerization degree corresponding to the amount of insulation paper deterioration index components obtained by the investigation of the degree of aging deterioration by dismantling of oil-filled electrical equipment, specifically 90 or more transformers, reactors, etc. Collect the measured values and use the measured values to set the lower limit range line and upper limit range line so that about 90% or more of the total measured values are included. The relationship with the degree of polymerization is illustrated.
[0019]
FIG. 2 shows a specific example using CO ₂ + CO as an insulating paper deterioration indicator component. The relationship between the amount of CO ₂ + CO in the insulating oil and the average degree of polymerization of the insulating paper is shown in the lower limit range line 2 and the upper limit range. This is illustrated by setting line 1. In this case, the width between the lower limit range line 2 and the upper limit range line 1 is determined by the distribution of the actual measurement values.
[0020]
Referring to FIG. 2 in more detail, point A is where the insulating paper average polymerization degree 450 line 3, lower limit range line 2, and CO ₂ + CO amount line 4 cross each other, and AA ′ is 0%. As shown, (1) when the amount of CO ₂ + CO is 0.2 ml / g, (2) the probability that the average degree of polymerization of the insulating paper is 450 or less is 0%.
[0021]
The point b is a point where the insulating paper average polymerization degree 450 line 3 and the CO ₂ + CO amount line 5 cross each other, and shows that the point between Bb out of the width BB ′ is 25%. When the amount of CO ₂ + CO is 0.37 ml / g, (2) the probability that the insulating paper average polymerization degree is 450 or less is 25%.
[0022]
In addition, the point c is a point where the insulating paper average polymerization degree 450 line 3 and the CO ₂ + CO amount line 6 cross each other. _{When the} amount of ₂ + CO is 0.67 ml / g, (2) the probability that the average degree of polymerization of the insulating paper is 450 or less is 50%.
[0023]
The point d is the point where the insulating paper average polymerization degree 450 line 3 and the CO ₂ + CO amount line 7 cross each other, and the point between Dd shows that 75% between Dd. (1) CO ₂ + CO When the amount is 1.2 ml / g, (2) the probability that the insulation paper average polymerization degree is 450 or less is 75%.
[0024]
Furthermore, the point E ′ is a point where the insulating paper average polymerization degree 450 line 3 and the upper limit range line 1 intersect, and since the interval between EE ′ is 100%, (1) CO ₂ + CO amount is 2.0 ml / g. (2) indicates that the probability that the average degree of polymerization of insulating paper is 450 or less is 100%.
[0025]
As explained above, the example in Fig. 2 shows the point A that intersects the lower limit range line 2 in relation to the average degree of polymerization of insulating paper with respect to the amount of CO ₂ + CO using the actual measurement values obtained by dismantling the actual equipment. The CO ₂ + CO amount is 0.2 ml / g and the probability that the average degree of polymerization of insulating paper is 450% or less is 0%. On the other hand, the CO ₂ + CO amount at the point E ′ intersecting with the upper limit range line 1 is 2.0 ml / g. The probability that the average degree of polymerization of insulating paper is 450 or less is 100%. Thus, when the amount of CO ₂ + CO is 0.2 ml / g to 2.0 ml / g, the probability that the insulation paper average polymerization degree is 450 or less is 0% to 100%. It is determined that the danger level has been reached at a probability of 100%.
[0026]
Next, a relationship diagram II is created based on the relationship diagram I.
The relationship diagram II shows the relationship between the insulating paper deterioration index component amount and the probability that the insulating paper average polymerization degree is 450 or less. FIG. 3 is given as a specific example of the relationship diagram II. FIG. 3 is derived from the relationship between the amount of CO ₂ + CO and the average degree of polymerization of insulating paper shown in FIG. 2. The probability that the average degree of polymerization of insulating paper with respect to the amount of CO ₂ + CO is 450 or less is 0% to 100%. It shows the relationship.
[0027]
Therefore, if the measured value of the amount of CO ₂ + CO in the insulating oil can be obtained, the probability that the average degree of polymerization of the insulating paper is 450 or less can be obtained by using FIG. For example, the CO ₂ + CO content in transformer insulating oil was measured when CO ₂ + CO per insulating paper unit weight is 0.4 ml / g, the insulating paper average polymerization degree of 450 or less is the probability of about 26% obtained It is done.
[0028]
The third step in the method of diagnosing the lifetime of oil-filled electrical equipment according to the present invention includes the probability that the average degree of polymerization of the insulation paper obtained in the second step is 450 or less and the insulation measured over time. Create a relationship diagram III (life curve) for each oil-filled electrical device that shows the relationship between the probability that the insulation paper average degree of polymerization is 450 or less calculated from the paper deterioration index component amount and the operating time, and use this to create the oil The content is to estimate the remaining life of electrical equipment.
[0029]
Specifically, FIG. 4 illustrates the relationship diagram III. By plotting the measurement results of the CO ₂ + CO amount in insulating oil over time (marked with ●) and the current measurement results (marked with ○). The obtained life curve is shown. Normally, the life curve differs depending on the operating conditions, etc., for each oil-filled electrical device, the time to reach 100% probability that the average degree of insulation paper is 450 or less. Regarding the life point, the probability that the insulation paper average polymerization degree is 450 or less can be arbitrarily set such as 100%, 90%, 80%, etc. in consideration of the characteristics of the oil-filled electrical device. FIG. 4 shows a transformer with a probability of 21%, 50% and 68% of the average degree of insulation paper being less than 450 in the operation time 5 years, 10 years and 15 years shown by curve (1), curve (2). The life curves of transformers with 21%, 50% and 68% probability of an insulation paper average degree of polymerization of 450 or less at 10 years, 20 years and 30 years are shown.
[0030]
In addition, when there is no measurement result of CO ₂ + CO amount over time in the past, and when measuring for the first time, the life curve is created assuming that the CO ₂ + CO amount has increased at a constant rate from the start of operation to the present, and the next measurement result The life curve may be corrected by adding
[0031]
In the description of the life curve, in the case of the transformer of curve (1), the remaining life at an operation time of 15 years is 15 years and 75% when the life point is 100% of the average degree of polymerization of the insulating paper is 100%. Then you can get 2 years.
[0032]
Moreover, in the case of the transformer of curve (2), the remaining life at the operation time of 30 years is 30 years when the life point is 100% probability that the average polymerization degree of the insulating paper is 450 or less, and 6 years when 75%. Can do.
[0033]
In this way, the measured value of the insulating paper deterioration index component amount in the insulating oil of the oil-filled electrical device does not require conversion to the insulating paper average polymerization degree, and there is a probability that the insulating paper average polymerization degree is 450 or less. Lifetime can be estimated.
[0034]
Therefore, according to the present invention,
Providing a method of obtaining the probability that the insulation paper average polymerization degree is 450 or less from the amount of the insulation paper deterioration index component in the insulation oil, and estimating the lifetime of the oil-filled electrical device by the transition of the probability It is.
[0035]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples. In addition, the measuring method utilized in the Example etc. is as follows.
[0036]
(1) CO ₂ + CO amount According to Petroleum Institute Standard JPI-5R-51-98 “Gas and insulating oil collection from oil-filled electrical equipment and analysis method for free and dissolved gas” (1998).
(2) Average degree of polymerization of insulating paper According to JEM1455 “Measuring method of average degree of polymerization of insulating paper for transformers” (1991).
[0037]
Example 1
Measurement of CO ₂ + CO amount Insulating oil is collected from transformer A (operating time 20 years), and the amount of CO ₂ + CO is measured by the method of the Petroleum Institute Standard JPI-5R-51-98 to insulate. A result of 0.92 ml per gram of paper was obtained.
[0038]
Was 65% was determined probabilities from CO ₂ + CO amount 0.92 ml / g is insulating paper average polymerization degree of 450 or less by using the calculated <br/> Figure 3 probability is insulating paper average polymerization degree of 450 or less.
[0039]
2 and 3 used here were prepared as follows.
Fig. 2 shows the relationship between the amount of formation and the average degree of polymerization of insulating paper when CO ₂ + CO is used as an insulating paper deterioration index component. From Electric Cooperative Research Vol. 54, No. 5 (Part 1) Quoted. The two curves in the figure indicate the range obtained from the results of dismantling investigation of 99 transformers, reactors, etc., and the amount of CO ₂ + CO with respect to insulation paper average polymerization degree 450 is 0.2 ml / g The concentration range was 2.0 ml / g, and this concentration range was regarded as a caution level. In addition, 0.2 ml / g or less has a probability of an insulating paper average polymerization degree of 450 or less being 0%, and 2.0 ml / g or more is 100%. The probability that the average degree of polymerization of the insulating paper is 450 or less is set for the level of caution. In the figure, the probability is 25%, 50%, and 75%, as shown by a straight line (solid line).
[0040]
FIG. 3 shows the relationship between the amount of CO ₂ + CO at the level of caution in FIG. 2 and the probability that the average degree of polymerization of the insulating paper is 450% or less when CO ₂ + CO is used as the insulating paper deterioration index component. It is a plot. Using this relationship, the probability that the insulating paper average polymerization degree was 450 or less was determined from the amount of CO ₂ + CO.
[0041]
Estimated remaining life Fig. 5 plotting CO ₂ + CO amount measured over time for transformer A over time (marked with ●) shows the probability that the average polymerization degree of insulating paper is 450 or less in the current operation time of 20 years. The results of evaluation were additionally plotted (marked with ◯) to create a life curve.
From this lifetime curve, the remaining life for transformer A under the same load condition was 26 years when the probability was 100%, 16 years when the probability was 90%, and 8 years when the probability was 80%.
[0042]
Example 2
When transformer B was operated for 20 years, the amount of CO ₂ + CO measured for the first time was 0.60 ml / g. From this measurement result, a result with a probability of 46% that the insulating paper average polymerization degree is 450 or less was obtained using FIG. Based on this result, the life curve of the transformer B shown in FIG. 6 was created. In addition, the life curve of the transformer B is a case where there is no past data, and was created assuming that the amount of CO ₂ + CO increased at a constant speed from the start of operation to the present.
As a result, the transformer B had a remaining life of 23 years when the probability was 80% under the same load condition, and a result of 30 years or more with a probability of 86% or more.
[0043]
Examples 3-6
For each of transformers C to F, an insulating oil sample was taken and the amount of CO ₂ + CO was measured, and the results shown in Table 1 were obtained. From these results, the probability that the insulating paper average degree of polymerization was 450 or less was determined using FIG. A life curve of each transformer is created by adding this probability value to the integrated value obtained by measuring over time in the past, and based on this, the remaining life when the probability is 80% is assumed as the life point. Estimated. The results are shown in Table 1.
[0044]
[Table 1]

[0045]
Comparative Example 1
Using the CO ₂ + CO amount (0.92 ml / g) of the transformer A measured in Example 1, the remaining life was estimated by a conventional method. From FIG. 2, the average polymerization degree of insulating paper with respect to CO ₂ + CO amount of 0.92 ml / g is 263 to 555, and the median is 409. Assuming that the life point is the average degree of polymerization of insulating paper 450, the transformer A has already reached the end of its life.
[0046]
Comparative Example 2
Using the CO ₂ + CO amount (0.60 ml / g) of transformer B measured in Example 2, the remaining life was estimated by a conventional method. From FIG. 2, the average polymerization degree of insulating paper with respect to CO ₂ + CO amount 0.60 ml / g is 305 to 621, and the median is 463. When estimating the remaining life of the transformer B using the formula Acker life points as insulating paper average polymerization degree of 450, L _O = 1000 becomes 1 year.
[0047]
From the examples and comparative examples, it can be seen that according to the conventional life diagnosis method, the conversion of the insulation paper deterioration index component amount into the insulation paper average polymerization degree is considerably varied, and accurate estimation cannot be performed.
[0048]
【The invention's effect】
As described above, according to the life diagnosis method for oil-filled electrical equipment of the present invention, the insulation paper average is not required without conversion from the insulation paper deterioration index component amount to the insulation paper average polymerization degree by the conventional method. Since the probability that the degree of polymerization is 450 or less can be obtained, and a life curve can be created from the transition of this probability to estimate the remaining life, there is an effect that it is simple and the accuracy of life diagnosis is improved.
[Brief description of the drawings]
FIG. 1 is a flowchart of a life diagnosis method for oil-filled electrical equipment according to the present invention.
FIG. 2 is a graph showing the relationship between the amount of CO ₂ + CO and the average polymerization degree of insulating paper for CO ₂ + CO as a result of dismantling investigation of actual devices such as transformers and reactors.
FIG. 3 is a graph showing the relationship between the amount of CO ₂ + CO determined from FIG. 2 and the probability that the insulating paper average polymerization degree is 450 or less.
FIG. 4 is a life curve represented by the transition of the probability that the average degree of polymerization of insulating paper is 450 or less.
FIG. 5 is a life curve of the transformer A of Example 1 as a transition of the probability that the average degree of polymerization of insulating paper is 450 or less.
6 is a life curve of the transformer B of Example 2 expressed as a transition of the probability that the average degree of insulation paper is 450 or less. FIG.

Claims

A method for diagnosing the life of an oil-filled electrical device that estimates the remaining life of the oil-filled electrical device from the amount of an insulation paper deterioration index component generated in the insulating oil,
1) Measure the amount of insulation paper deterioration index component in the insulation oil collected from the oil-filled electrical equipment,
2) From the measured value of the insulation paper deterioration index component amount obtained in 1) above, using the relationship diagram II created through the following Steps 1 and 2, the oil-filled electrical equipment Find the probability of belonging to oil-filled electrical equipment with a polymerization degree of 450 or less
Step 1: Statistical Examination by possible number dismantling of the oil-filled electrical device of the analysis, that corresponds to the measured value and the measured value of the collected historical insulating paper degradation index component amounts insulating paper average polymerization degree of the measured values of to include 90% of the total number of measurements, the in relationship insulating paper degradation indicator component amount and the insulating paper average polymerization degree, an upper limit range lines 1 and lower limit range line 2, these cross with two of the lines and the lines 5, 6 and 7, to create a relationship diagram I as set insulating paper average polymerization degree of 450 line 3 indicates the probability is insulating paper average polymerization degree of 450 or less, respectively the intersection.
Step 2: Based on the relationship diagram I, a relationship diagram showing the correspondence between the amount of insulation paper deterioration index component and the probability of oil-filled electrical equipment belonging to oil-filled electrical equipment having an insulation paper average polymerization degree of 450 or less of 0% to 100% Create II.
3) Probability of the average degree of polymerization of insulating paper of 450 or less obtained from the probability of the oil-filled electrical equipment obtained in 2) above and the amount of the insulating paper deterioration index component measured over time of the oil-filled electrical equipment to date The remaining life of the oil-filled electrical device is estimated using the relationship diagram III created on the basis of the corresponding operation time and the oil-filled electrical device life diagnosis method.

The life diagnosis method for oil-filled electrical equipment according to claim 1, wherein the insulating paper deterioration index component is carbon dioxide and carbon monoxide (CO ₂ + CO), furfural or acetone.