JP3707271B2 - Gas-insulated static induction device and method of operating the same - Google Patents

Description

の関係を満足するガス温度ｔ℃とガス圧力ＰＭＰａの運転線上の状態を維持することになる。他方、ＣＦ₃Ｉ の蒸気圧曲線の−２０℃における飽和圧力は0.1092ＭＰａであり、蒸気圧曲線の高温側(グラフの右側)は気体なので、もし、−２０℃で飽和蒸気の状態であるＣＦ₃Ｉ の温度が高温側に変化すると、そのガス温度ｔ℃とガス圧力ＰＭＰａとの関係は、図４に示すごとく、
Ｐ＝（０.１０９２／２５３.１５)・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔ［Ｋ］で表すと、Ｐ＝(０.１０９２／２５３.１５)・Ｔとなり、華氏温度：ｔ_F［゜Ｒ］で表すと、Ｐ＝（０.１０９２／４５５.６７)・(ｔ_F＋４５９.６７）となる）
になる。このため、−２０℃の最低気温から許容最高ガス温度に至る運転範囲でＣＦ₃Ｉ が液化することなく、気体の状態を保ち、ガス温度が変化しても絶縁耐力が低下するのを防ぐためには、変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス圧力ＰＭＰａとの間に
Ｐ＜（０.１０９２／２５３.１５)・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔ［Ｋ］で表すと、Ｐ＜(０.１０９２／２５３.１５)・Ｔとなり、華氏温度：ｔ_F［゜Ｒ］で表すと、Ｐ＜（０.１０９２／４５５.６７)・(ｔ_F＋４５９.６７）となる）
の関係が成り立つようにＣＦ₃Ｉ を封入すればよいことがわかる。
【００２３】
図５は屋内に設置された変圧器の絶縁冷却媒体としてＣＦ₃Ｉ を用いた場合の変圧器の運転方法の一実施例であり、ＪＥＣ−２２００に規定されている運転を保証する最低気温が−５℃の場合である。
【００２４】
この場合は、最低気温が屋外の場合の−２０℃から−５℃に変わっただけであり、同様の考え方が成り立ち、ＣＦ₃Ｉの−５℃における飽和圧力が０.１９１８ＭＰａであることから、−５℃の最低気温から許容最高ガス温度に至る運転範囲でＣＦ₃Ｉ が液化することなく、気体の状態を保ち、ガス温度が変化しても絶縁耐力が低下するのを防ぐためには、変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス圧力ＰＭＰａとの間に
Ｐ＜（０.１９１８／２６８.１５)・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔ［Ｋ］で表すと、Ｐ＜(０.１９１８／２６８.１５)・Ｔとなり、華氏温度：ｔ_F［゜Ｒ］で表すと、Ｐ＜(０.１９１８／４８２.６７)・ (ｔ_F＋４５９.６７）となる）
の関係が成り立つようにＣＦ₃Ｉ を封入すればよい。
【００２５】
そのほか、ＩＥＣやＡＮＳＩでも、変圧器の運転を保証する最低気温が規定されており、その最低気温ｔmin℃におけるＣＦ₃Ｉ の飽和圧力をＰminＭＰａとすると、変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス圧力ＰＭＰａとの関係が
Ｐ＜（Ｐmin／（ｔmin２７３.１５))・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔmin，Ｔ［Ｋ］で表すと、Ｐ＜（Ｐmin／Ｔmin)・Ｔとなり、華氏温度：ｔ_Fmin，ｔ_F［゜Ｒ］で表すと、Ｐ＜（Ｐmin／（ｔ_Fmin＋４５９.６７))・(ｔ_F＋４５９.６７）となる）
を満足するようにＣＦ₃Ｉ を封入すればよい。
【００２６】
図６は屋外に設置された変圧器の絶縁冷却媒体としてＣＦ₃Ｉ を含む混合物を用いた場合の変圧器の運転方法の一実施例であり、ＪＥＣ−２２００に規定されている運転を保証する最低気温が−２０℃の場合である。この場合は、運転範囲における変圧器内の混合物の最高ガス圧力、即ち、許容最高ガス温度における圧力が０.２９７５ＭＰａ（２kg／cm²Ｇ）に満たない例である。こうすることによって変圧器のタンクが第二種圧力容器の規制を免れることができる。
【００２７】
ＣＦ₃Ｉ と他の物質の混合物の場合、ＣＦ₃Ｉ の液化は、ＣＦ₃Ｉ 単独の場合と異なり、変圧器内の圧力ではなく、ＣＦ₃Ｉ の分圧で評価しなければならない。−２０℃で飽和蒸気になるＣＦ₃Ｉ のガス温度ｔ℃とガス圧力ＰＭＰａとの間には、前述の通り
Ｐ＝（０.１０９２／２５３.１５)・(ｔ＋２７３.１５）
の関係がある。ＣＦ₃Ｉと他の物質の混合物では、ガス温度ｔ℃におけるＣＦ₃Ｉのガス分圧Ｐ_CF3Iがこの圧力に達しなければ、−２０℃の最低気温から許容最高ガス温度に至る運転範囲で、ＣＦ₃Ｉ の液化が生じることはない。そのため、
ＣＦ₃Ｉ を含む混合物を絶縁冷却媒体とするガス絶縁変圧器では、ＣＦ₃Ｉ のガス温度ｔ℃とガス分圧Ｐ_CF3IＭＰａとの間に
Ｐ_CF3I＜（０.１０９２／２５３.１５)・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔ［Ｋ］で表すと、Ｐ_CF3I＜(０.１０９２／２５３.１５)・Ｔとなり、華氏温度：ｔ_F［゜Ｒ］で表すと、Ｐ_CF3I＜(０.１０９２／455.67)・（ｔ_F＋４５９.６７）となる）
の関係が成り立つようにＣＦ₃Ｉ を封入すればよい。
【００２８】
ＣＦ₃Ｉ を含む混合物のＣＦ₃Ｉ 以外の物質としては、電気絶縁性に優れ、不燃性で、毒性がなく、地球温暖化係数，オゾン破壊係数とも０であり、かつ、安価なＮ₂ が好ましく用いることができるが、ヘリウム，ネオン，アルゴン，キセノンのような希ガス、あるいは、ＣＯ₂ その他の汎用物質を用いることができる。また、ＳＦ₆ ，Ｃ₂Ｆ₆，Ｃ₄Ｆ₈等と混合して用いて、電気絶縁性に優れるが、地球温暖化係数が大きいこれらの物質の使用量を低減することができる。
【００２９】
ＣＦ₃Ｉ に他の物質を加えると、その物質によってＣＦ₃Ｉ 単独の時に比べて絶縁耐力や冷却能力が向上し、変圧器の大容量化や小型化が図れることになる。
絶縁耐力や冷却能力のより一層の向上を図るために、運転範囲における変圧器の最高ガス圧力が０.２９７５ＭＰａ（２kg／cm²Ｇ）以上になるようにＣＦ₃Ｉ 以外の物質を封入することも可能である。ただし、その場合、変圧器のタンクは第二種圧力容器になる。
【００３０】
図７は屋内に設置された変圧器の絶縁冷却媒体としてＣＦ₃Ｉ を含む混合物を用いた場合の変圧器の運転方法の一実施例であり、ＪＥＣ−２２００に規定されている運転を保証する最低気温が−５℃の場合である。この場合は最低気温が、屋外の場合の−２０℃から−５℃に変わっただけで、同様の考え方が成り立ち、−５℃の最低気温から許容最高ガス温度に至る運転範囲で、ＣＦ₃Ｉ が液化しないようにするためには、変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス分圧Ｐ_CF3Iとの間に
Ｐ_CF3I＜（０.１９１８／２６８.１５)・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔ［Ｋ］で表すと、Ｐ_CF3I＜(０.１９１８／２６８.１５)・Ｔとなり、華氏温度：ｔ_F［゜Ｒ］で表すと、Ｐ_CF3I＜(０.１９１８／482.67)・(ｔ_F＋４５９.６７）となる）
の関係が成り立つようにＣＦ₃Ｉ を封入すればよい。
【００３１】
そのほか、ＩＥＣやＡＮＳＩで変圧器の運転を保証する最低気温に対しても、最低気温ｔmin℃におけるＣＦ₃Ｉ の飽和圧力がＰminＭＰａのときに、ＣＦ₃Ｉ を含む混合物を絶縁冷却媒体とする変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス分圧Ｐ_CF3IＭＰａとの関係が
Ｐ_CF3I＜（Ｐmin／（ｔmin＋２７３.１５))・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔmin，Ｔ［Ｋ］で表すと、Ｐ_CF3I＜（Ｐmin／Ｔmin)・Ｔとなり、華氏温度：ｔ_Fmin，ｔ_F［゜Ｒ］で表すと、Ｐ_CF3I＜(Ｐmin／(ｔ_Fmin＋４５９.６７))・（ｔ_F＋４５９.６７）となる）
を満足するようにＣＦ₃Ｉ を封入すればよい。
【００３２】
ところで、上述した各式のうち、Ｐ＜（０.１０９２／２５３.１５)・(ｔ＋２７３.１５），Ｐ＜（０.１９１８／２６８.１５)・(ｔ＋２７３.１５），Ｐ＜（Ｐmin／(ｔmin＋２７３.１５))・(ｔ＋２７３.１５)では、ＣＦ₃Ｉのガス圧力が０.１０１３ＭＰａ(大気圧）以上，０.２９７５ＭＰａ(２kg／cm²Ｇ)未満であればよく、また、Ｐ_CF3I＜(０.１０９２／２５３.１５)・(ｔ＋２７３.１５）、Ｐ_CF3I＜（０.１９１８／２６８.１５)・(ｔ＋２７３.１５)，Ｐ_CF3I＜(Ｐmin／（ｔmin＋２７３.１５))・(ｔ＋２７３.１５）では、ＣＦ₃Ｉ のガス分圧が０.１０１３ＭＰａ（大気圧）以上、０.２９７５ＭＰａ(２kg／cm²Ｇ）未満であればよい。
【００３３】
その根拠を図１１を用いて説明する。図１１に示すごとく、ＣＦ₃Ｉ の ０.１０１３ＭＰａ（大気圧）における飽和温度（沸点）は−２２.５℃であり、屋外設置の場合にＪＥＣ−２２００で規定されている運転を保証する最低気温−２０℃より低く、ＪＥＣ−２２００の最低気温である−２０℃を含むことになる。０.２９７５ＭＰａ（２kg／cm²Ｇ）未満は、実施例で説明している第二種圧力容器の規制を免れることができる圧力である。ＪＥＣ−２２００の屋内設置の場合の運転を保証する最低気温である−５℃におけるＣＦ₃Ｉ の飽和圧力は ０.１９１８ＭＰａ であり、この状態から温度が上昇したときのＣＦ₃Ｉ のガス温度ｔ℃とガス圧力ＰＭＰａの関係を表す
Ｐ＝（０.１９１８／２６８.１５)・(ｔ＋２７３.１５）
の式で、Ｐ＝０.２９７５ＭＰａになる温度を求めると、ｔ＝１４２.８℃となり、変圧器で使用するガス温度（最高１００℃程度）を十分カバーできることになる。
【００３４】
図８は変圧器の絶縁冷却媒体としてＣＦ₃Ｉ を用いた場合の変圧器の運転方法の一実施例であり、変圧器の運転を保証する最低気温ｔmin℃ におけるＣＦ₃Ｉ の飽和圧力がＰminＭＰａであり、変圧器内のＣＦ₃Ｉのガス温度ｔ℃とガス圧力ＰＭＰａの関係が
Ｐ≧（Ｐmin／（ｔmin＋２７３.１５))・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔmin，Ｔ［Ｋ］で表すと、Ｐ≧（Ｐmin／Ｔmin）・Ｔ となり、華氏温度：ｔ_Fmin，ｔ_F［゜Ｒ］で表すと、Ｐ≧（Ｐmin／（ｔ_Fmin＋４５９.６７))・（ｔ_F＋４５９.６７）となる）
の場合である。この場合、気温が低くて起動時等のように変圧器タンク内のCF₃Iのガス温度が低い時にはＣＦ₃Ｉ が液化する。それを防ぐためのガス絶縁変圧器の構成を図１に示す。
【００３５】
該図において、１は変圧器タンクで、この変圧器タンク１内に鉄心２、及びこの鉄心２に巻回された巻線３からなる変圧器中身を収納し、さらに、この変圧器タンク１内には絶縁冷却媒体４であるＣＦ₃Ｉ が
Ｐ≧（Ｐmin／（ｔmin＋２７３.１５))・(ｔ＋２７３.１５）
になるような圧力で封入してある。また、変圧器タンク１内部には、できるだけ多量のＣＦ₃Ｉ が鉄心２および巻線３内を流れるように変圧器タンク１内を仕切る仕切板５が設置されており、変圧器タンク１内部の上部空間６と下部空間７が連通しないように区切られている。１０は冷却器であり、上部配管１２を介して上部空間６とつながっている。また、下部空間７とは、送風機１１を経由して下部配管１３でつながっている。変圧器タンク１の下部にはＣＦ₃Ｉ の温度を上昇させる加熱手段である電気ヒータ１４が設けられている。変圧器タンク１の上部にはＣＦ₃Ｉ の温度を測定する温度検知器２０と圧力を測定する圧力検知器２１が設けられている。また、冷却器１０の冷却水１５の流量を測定する流量検知器２２と流量を制御する流量制御弁２３、さらに、電気ヒータ１４の入力を測定する電力計２４と入力を制御する入力制御器２５が設置されている。２６は演算器であり、後述詳細説明するが、電力計２４の値を参照しながら電気ヒータ１４の入力の制御信号を入力制御器２５に送信するものである。
【００３６】
このような構成にすれば、電気ヒータ１４でＣＦ₃Ｉ を加熱して温度を上昇させることもできるし、ＣＦ₃Ｉ の温度や圧力を温度検知器２０や圧力検知器２１で知ることができる。
【００３７】
図８に示すように、変圧器の定格負荷条件のＣＦ₃Ｉ のガス温度をｔ_f℃ ，ガス圧力をＰ_fＭＰａ、また、比重量（密度）をγkg／ｍ³，ガス定数をＲとすると、気体の状態のＣＦ₃Ｉ は

（これは絶対温度：Ｔ_f，Ｔ［Ｋ］で表すと、Ｐ＝(Ｐ_f／Ｔ_f)・Ｔ＝γＲＴとなり、華氏温度：ｔ_F,f，ｔ_F［゜Ｒ］で表すと、Ｐ＝(Ｐ_f／(ｔ_F,f＋４５９.６７)）・（ｔ_F＋４５９.６７）＝γＲ（ｔ_F＋４５９.６７）となる）
で表されるガス温度ｔ℃とガス圧力ＰＭＰａの運転線上の状態を保つことになる。この直線とＣＦ₃Ｉ の蒸気圧曲線の交点の温度以上になるように加熱手段によって加熱してＣＦ₃Ｉ のガス温度を維持すれば、気温が低くて起動時等のように変圧器全体が十分に暖まっていないときでもＣＦ₃Ｉ の液化が生じないので、絶縁耐力の低下を防止することができる。
【００３８】
先程述べた温度検知器２０と圧力検知器２１からＣＦ₃Ｉ ４の温度と圧力を知ることができるので、

とＣＦ₃Ｉ の蒸気圧曲線の交点の温度、あるいは、圧力、あるいは温度と圧力の両方の値と温度検知器２０から得られる温度、あるいは圧力検知器２１から得られる圧力、あるいは温度検知器２０と圧力検知器２１から得られる温度と圧力の両方を演算器２６で比較し、交点の温度以上、あるいは交点の圧力以上、あるいは温度，圧力とも交点の値以上となるように、演算器２６から電力計２４の値を参照しながら電気ヒータ１４の入力の制御信号を入力制御器２５に送って加熱量を制御することによって図８に示した運転が可能になる。
【００３９】
加熱手段は必ずしも、電気ヒータ１４である必要はなく、変圧器タンク１の下部に設けられた配管に高温水や水蒸気のような高温の流体を流してもよいし、冷却器１０に供給する冷却水１５をＣＦ₃Ｉ の加熱が必要なときだけ高温の流体に替えてもよい。また、加熱手段の設置場所は変圧器タンク１の下部に限らない。例えば、冷却器１０と変圧器タンク１とを連通させる配管に設けてもよい。
【００４０】
この運転方法は、ＣＦ₃Ｉ のガス圧力を高くすることができるので、密度（比重量）が大きくなり、絶縁耐力を大きくすることができ、変圧器の高圧化や大容量化，小型化が可能になる。
【００４１】
本実施例では導ガス水冷方式について述べたが、冷却方式が他の方式でも同じ効果が得られる。
【００４２】
図９は変圧器の絶縁冷却媒体としてＣＦ₃Ｉ を含む混合物を用いた場合の変圧器の運転方法の一実施例であり、変圧器の運転を保証する最低気温ｔmin℃ におけるＣＦ₃Ｉ の飽和圧力がＰminＭＰａ であり、変圧器内のＣＦ₃Ｉ のガス温度ｔ℃とガス分圧Ｐ_CF3IＭＰａの関係が
Ｐ_CF3I≧（Ｐmin／（ｔmin＋２７３.１５))・(ｔ＋２７３.１５）
（これは、絶対温度：Ｔmin，Ｔ［Ｋ］で表すと、Ｐ_CF3I≧(Ｐmin／Ｔmin）・Ｔとなり、華氏温度：ｔ_Fmin，ｔ_F［゜Ｒ］で表すと、Ｐ_CF3I≧（Ｐmin／(ｔ_Fmin＋４５９.６７))・（ｔ_F＋４５９.６７）となる）
の場合である。ＣＦ₃Ｉ と他の物質の混合物の場合、ＣＦ₃Ｉの液化はＣＦ₃Ｉの分圧で評価すればよく、変圧器の定格負荷条件のＣＦ₃Ｉ のガス温度ｔ_f℃ 、ガス分圧をＰ_f,CF3I ＭＰａ、また、比重量（密度）をγkg／ｍ³，ガス定数をＲとすると、

（ここで、絶対温度：Ｔ_f，Ｔ［Ｋ］で表すと、Ｐ＝（Ｐ_f,CF3I ／Ｔ_f）・Ｔ＝γＲＴとなり、華氏温度：ｔ_F,f，ｔ_F［゜Ｒ］で表すと、Ｐ＝（Ｐ_f,CF3I ／ （ｔ_F,f＋４５９.６７))・（ｔ_F＋４５９.６７）＝γＲ（ｔ_F＋４５９.６７）となる）
とＣＦ₃Ｉ の蒸気圧曲線の交点の温度以上になるように上記加熱手段によって加熱して、ＣＦ₃Ｉ を含む混合物のガス温度を飽和温度以上に保てば、起動時等のように変圧器全体の温度が低いときにもＣＦ₃Ｉ を含む混合物は液化しないので、絶縁耐力の低下を防ぐことができる。
【００４３】
この運転方法も、ＣＦ₃Ｉ 以外の物質によってＣＦ₃Ｉ 単独のときに比べて絶縁耐力が向上し、変圧器の高圧化や大容量化，小型化が図れることになる。
【００４４】
図１０は図１に示した実施例の変形例であり、図１と異なるのは電気ヒータと電力計、及び入力制御器を備えていない点であり、その他の構成は図１と同様である。
【００４５】
このような本実施例の構成とすれば、気温の低い寒冷地域や冬季に変圧器を起動する場合、定期点検による運転停止後に変圧器を再起動する場合等、変圧器タンク１内のガス温度が飽和温度と等しいときには、変圧器自身を運転する前に送風機１１のみを運転し、変圧器タンク１の絶縁冷却媒体４であるＣＦ₃Ｉ を循環させて、変圧器タンク１内のＣＦ₃Ｉの飽和温度より高い温度になるまでＣＦ₃Ｉを暖め、飽和温度より高い温度になった時点で変圧器本体を運転することが可能となる。変圧器タンク１内のＣＦ₃Ｉ の温度や圧力は、図１と同様に温度検知器２０や圧力検知器２１で知ることができる。
【００４６】
尚、上述した実施例では、ＣＦ₃Ｉ の液化を防止する加熱手段として電気ヒータを用いて説明したが、巻線に所定の電圧ではなく低電圧をかけて電界を小さくしておいてガスを暖め、液化が生じない温度以上になると所定の電圧をかけるという運転も可能であり、このようにしてガスを暖めるものも加熱手段に含まれる。
【００４７】
【発明の効果】
以上説明したように本発明によれば、ＣＦ₃Ｉ 、あるいはＣＦ₃Ｉ を含む混合物を絶縁冷却媒体として用いるガス絶縁静止誘導電器の運転を保証する気温の範囲において、ＣＦ₃Ｉ の液化が生じなくなり、絶縁耐力の低下が防止できる結果、電気絶縁性に優れ、不燃性で、毒性がほとんど無く、なおかつ、地球温暖化係数がＣＯ₂ より小さく、オゾン破壊係数０のガス絶縁静止誘導電器の運転が可能になる。
【図面の簡単な説明】
【図１】本発明の一実施例として示したガス絶縁変圧器の構成図である。
【図２】ＣＦ₃Ｉ とＳＦ₆ のＡＣ破壊電圧の測定結果を示す特性図である。
【図３】ＣＦ₃Ｉ を絶縁冷却媒体とする変圧器の運転範囲を示す特性図である。
【図４】ＣＦ₃Ｉ を絶縁冷却媒体とする変圧器を屋外に設置し、最低気温が−２０℃の場合の運転範囲を示す特性図である。
【図５】ＣＦ₃Ｉ を絶縁冷却媒体とする変圧器を屋内に設置し、最低気温が−５℃の場合の運転範囲を示す特性図である。
【図６】ＣＦ₃Ｉ を含む混合物を絶縁冷却媒体とする変圧器を屋外に設置し、最低気温が−２０℃の場合の運転範囲を示す特性図である。
【図７】ＣＦ₃Ｉ を含む混合物を絶縁冷却媒体とする変圧器を屋内に設置し、最低気温が−５℃の場合の運転範囲を示す特性図である。
【図８】ＣＦ₃Ｉ を絶縁冷却媒体とする変圧器の他の実施例における運転範囲を示す特性図である。
【図９】ＣＦ₃Ｉ を含む混合物を絶縁冷却媒体とする変圧器の他の実施例における運転範囲を示す特性図である。
【図１０】本発明の他の実施例として示した変圧器の構成図である。
【図１１】ＣＦ₃Ｉ の蒸気圧曲線と低ガス圧変圧器の運転範囲を示す特性図である。
【図１２】従来のガス絶縁変圧器を示す構成図である。
【符号の説明】
１…変圧器タンク、２…鉄心、３…巻線、４…絶縁冷却媒体、５…仕切板、６…タンク上部空間、７…タンク下部空間、１０…冷却器、１１…送風機、１２…上部配管、１３…下部配管、１４…電気ヒータ、１５…冷却水、２０…温度検知器、２１…圧力検知器、２２…流量検知器、２３…流量制御弁、２４…電力計、２５…入力制御器、２６…演算器。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas-insulated static induction appliance and a method for operating the gas-insulated static induction device._ThreeThe present invention relates to a gas-insulated static induction appliance suitable for use as an insulation and cooling medium such as a transformer or a reactor, and an operation method thereof.
[0002]
[Prior art]
Conventionally, an oil-insulated type that mainly performs insulation and cooling using insulating oil has been the mainstream of static induction electric appliances such as transformers. However, in the case of an oil-filled electrical device, there is a possibility that an accident such as an oil may occur when an accident occurs. In particular, in recent years, substation facilities such as transformers are often installed in urban areas due to restrictions on installation locations in urban areas, and countermeasures for disaster prevention have become an important issue.
[0003]
Therefore, instead of insulating oil, there is a tendency to adopt gas-insulated transformers that use non-combustible gases that are less likely to cause disasters and that are highly safe as insulating and cooling media. And miniaturization is required. As a typical gas-insulated cooling medium, SF is excellent in electrical insulation, nonflammable, non-toxic and chemically stable.₆Etc.
[0004]
However, in recent years, when compounds such as CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon) are released into the atmosphere, the surface temperature rises due to the destruction of the ozone layer and the greenhouse effect in the stratosphere. Environmental pollution is a problem. For this reason, the production and consumption of these CFCs and HCFCs are regulated in stages, and selection of alternatives has been promoted worldwide. Chemically stable and persistent SF₆Has a global warming potential of CO₂Since it is very large compared to₆It is expected that regulations on emissions will be promoted. SF₆In addition, as an insulating cooling medium that is excellent in electrical insulation, non-flammable, non-toxic and chemically stable for use in electrical equipment, C₂F₆, C_FourF₈In all cases, the global warming potential is CO₂Very large compared to
[0005]
Global warming potential is CO₂Compared to CF, it is small in size, ozone destruction is 0, non-flammable and extremely toxic_ThreeThere is I.
[0006]
[Problems to be solved by the invention]
By the way, in general, in a gas-insulated transformer, the pressure is increased from the atmospheric pressure in order to increase the dielectric strength. Also, JEC (TheJapaneseElectrotechnicalCommittee) -2200, transformer operation must be guaranteed to a minimum temperature of -20 ° C for outdoor installations and to -5 ° C for indoor installations. In addition, IEC (InternationalElectrotechnicalCommission) and ANSI (AmericanNationalStandardsInstitute) also stipulates the minimum temperature that must be guaranteed.
[0007]
CF mentioned above_ThreeI has a boiling point (saturation temperature at atmospheric pressure) of −22.5 ° C. and is a gas at normal temperature and pressure, but the saturation temperature is SF₆This CF is higher than_ThreeWhen I is used as the insulating cooling medium of the transformer, liquefaction may occur in the low temperature region that ensures operation of the transformer. If liquefaction occurs in a low temperature region that guarantees the operation of the transformer, the dielectric strength is drastically reduced, which may lead to dielectric breakdown.
[0008]
The present invention has been made in view of the above points, and its object is to provide CF as an insulating cooling medium._ThreeEven in the case of using I 2, the CF in the temperature range that guarantees the operation of the gas-insulated static induction device_ThreeLiquefaction of I does not occur, the insulation strength is prevented from decreasing and the electrical insulation without breakdown is ensured, and it is nonflammable, hardly toxic, and has a global warming potential Is CO₂It is an object of the present invention to provide a gas insulated static induction apparatus having a smaller ozone depletion coefficient and an operation method thereof.
[0009]
[Means for Solving the Problems]
CF_ThreeFIG. 2 shows an AC breakdown voltage as an example of the dielectric strength of I 2. In this figure, the horizontal axis indicates the gas pressure (MPa), and the AC breakdown voltage (SF)₆0.1 MPa standard) is shown on the vertical axis. As is clear from the figure, CF_ThreeThe electrical insulation of I is SF in the gas state.₆Is equivalent to or better than In addition, chemical stability is easily decomposed by light, but in a transformer, it is used in a tank so that it is not a problem in practice.
[0010]
Fig. 3 shows an example of an ultra-high-pressure, large-capacity gas-insulated transformer. The operating line at a rated load condition of 85 ° C and pressure of 0.6MPa is plotted with the gas temperature t (° C) on the horizontal axis, ).
[0011]
CF in a sealed space like a transformer_ThreeWhen I is confined, CF_ThreeAs shown in FIG. 3, in the gas state above the saturation temperature, I 2 maintains a constant density (specific weight) even if the temperature changes, and CF 1_ThreeI will not liquefy. But CF_ThreeI has a boiling point (saturation temperature at atmospheric pressure) of −22.5 ° C. and a saturation temperature of SF.₆The temperature of the gas in the transformer tank is equal to the saturation temperature, such as when starting up a transformer in a cold region where the temperature is low or in winter, or restarting the transformer after shutting down due to periodic inspection. It is possible. In this case, when the gas temperature in the tank decreases, liquefaction begins to intersect the vapor pressure curve, deviates from a constant density state, changes to a temperature and pressure along the vapor pressure curve, and the pressure rapidly decreases. Since the density (specific weight) of the gas is proportional to the pressure if the temperature is the same, the density (specific weight) of the gas also rapidly decreases. AC breakdown voltage V, an example of dielectric strength_BDAnd the density (specific weight) γ of the gas is roughly
V_BD∝ γ^0.9
AC breakdown voltage V_BDAlso decreases rapidly. Therefore, CF, which is the insulating cooling medium in the tank, in the temperature range that guarantees the operation of the gas insulating transformer_ThreeIf liquefaction occurs in I 2, the dielectric strength may drop rapidly, leading to dielectric breakdown, and this point needs to be considered.
[0012]
Therefore, in the present invention, in order to achieve the above object, CF_ThreeI or CF_ThreeWhen operating using a mixture containing I as an insulating cooling medium, the CF_ThreeI is characterized in that it is always kept in a gaseous state.
[0013]
Specifically, CF_ThreeCF at the minimum temperature tmin ° C that guarantees the operation of equipment with I as the insulating cooling medium_ThreeCF in the apparatus tank when the saturation pressure of I is Pmin MPa_ThreeThe relationship between the gas temperature t of I and the gas pressure PMPa is
P <(Pmin / (tmin + 273.15)). (T + 273.15)
It is characterized by satisfying.
[0014]
CF_ThreeCF at the minimum temperature tmin ° C. which guarantees the operation of the apparatus using the mixture containing I as the insulating cooling medium_ThreeCF in the apparatus tank when the saturation pressure of I is Pmin MPa_ThreeI gas temperature t ° C and gas partial pressure P_CF3IThe relationship with MPa
P_CF3I<(Pmin / (tmin + 273.15)) · (t + 273.15)
It is characterized by satisfying.
[0015]
CF_ThreeCF at the minimum temperature tmin ° C that guarantees the operation of equipment with I as the insulating cooling medium_ThreeThe saturation pressure of I is Pmin MPa, and CF in the apparatus tank_ThreeThe relationship between the gas temperature t of I and the gas pressure PMPa is
P ≧ (Pmin / (tmin + 273.15)) · (t + 273.15)
In the case of_ThreeIt is expressed using the specific weight (density) γ of I and the gas constant R.
P = γR (t + 273.15)
And CF_ThreeThe temperature is equal to or higher than the temperature at the intersection of the vapor pressure curves of I 2.
[0016]
In addition, CF_ThreeCF at the minimum temperature tmin ° C. which guarantees the operation of the apparatus using the mixture containing I as the insulating cooling medium_ThreeThe saturation pressure of I is Pmin MPa, and CF in the apparatus tank_ThreeI gas temperature t ° C and gas partial pressure P_CF3IMPa relationship
P_CF3I≧ (Pmin / (tmin + 273.15)) · (t + 273.15)
In the case of_ThreeIt is expressed using the specific weight (density) γ of I and the gas constant R.
P_CF3I= ΓR (t + 273.15)
And CF_ThreeThe temperature is equal to or higher than the temperature at the intersection of the vapor pressure curves of I 2.
[0017]
CF_ThreeWhen a mixture containing I is used as an insulating cooling medium, CF_ThreeSubstances other than I are excellent in electrical insulation, nonflammable, non-toxic, have both global warming potential and ozone depletion potential of 0, and are inexpensive N₂Can be preferably used, but rare gas such as helium, neon, argon, xenon, or CO₂Other general-purpose substances can be used. SF₆, C₂F₆, C_FourF₈It is possible to reduce the amount of use of these substances having a high global warming potential, although they are excellent in electrical insulation properties.
[0018]
That is, in such a gas-insulated static induction electric appliance or its operation method, the CF in the apparatus tank can be used even at the lowest temperature guaranteed by the operation of the apparatus._ThreeThe gas temperature of I is the CF in the equipment tank_ThreeSince it is kept above the saturation temperature at the gas pressure of I 2 or the gas partial pressure, CF_ThreeI will not liquefy. For this reason, the CF at the gas temperature in the operating range_ThreeThe density (specific weight) of I is constant, the decrease in dielectric strength represented by the AC breakdown voltage is prevented, and excellent electrical insulation can be ensured. That is, CF_ThreeI or CF_ThreeBy using a mixture containing I as an insulating cooling medium, it has excellent electrical insulation, is nonflammable, has almost no toxicity, and has a global warming potential of CO2.₂It becomes smaller and can be used as a gas-insulated static induction machine having an ozone depletion coefficient of 0.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, a transformer is taken up as an example of a gas-insulated static induction appliance.
[0020]
First, the structure of the gas insulated transformer will be described with reference to FIG. In the figure, reference numeral 1 denotes a transformer tank. The transformer tank 1 contains an iron core 2 and a transformer 3 comprising a winding 3 wound around the iron core 2. Is filled with a gas which is an insulating cooling medium 4. In addition, a partition plate 5 for partitioning the transformer tank 1 is installed in the transformer tank 1 so that as much insulating cooling medium 4 as possible flows in the iron core 2 and the winding 3. The upper space 6 and the lower space 7 are partitioned so as not to communicate with each other. A cooler 10 is connected to the upper space 6 through the upper pipe 12. The lower space 7 is connected by a lower pipe 13 via a blower 11. Above the transformer tank 1, a temperature detector 20 for measuring the temperature of the insulating cooling medium 4 and a pressure detector 21 for measuring the pressure are provided.
[0021]
Figure 4 shows CF as an insulating cooling medium for transformers installed outdoors._ThreeIt is one Example of the operation method of the transformer at the time of using I, and is the case where the minimum temperature which guarantees the operation | movement prescribed | regulated to JEC-2200 is -20 degreeC.
[0022]
Usually CF in transformer_ThreeThe gas temperature of I varies between a minimum temperature of −20 ° C. and a maximum allowable gas temperature determined from the heat resistance class of the transformer and the cooling design. CF enclosed in a transformer that is a sealed space_ThreeIn gas state, the density (specific weight) is constant even if the temperature changes. For gases, the gas temperature t ° C., the gas pressure PMPa and the specific weight (density) γkg / m^ThreeIn between
P = γR (t + 273.15)
(This is expressed as absolute temperature: T [K], P = γRT, Fahrenheit temperature: t_FIn terms of [° R], P = γR · (t_F+45.9.67))
Since the equation of state holds and the gas constant R takes a constant value depending on the kind of gas, P / (t + 273.15) becomes a constant value. Therefore, the gas temperature at the rated load condition of the transformer is t_f℃, gas pressure is P_fAssuming MPa, CF in a gaseous state_ThreeI is as shown in FIG.

Thus, the state on the operating line of the gas temperature t ° C. and the gas pressure PMPa satisfying the above relationship is maintained. On the other hand, CF_ThreeThe saturation pressure at −20 ° C. of the vapor pressure curve of I is 0.1092 MPa, and the high temperature side (right side of the graph) of the vapor pressure curve is a gas._ThreeWhen the temperature of I changes to the high temperature side, the relationship between the gas temperature t ° C. and the gas pressure PMPa is as shown in FIG.
P = (0.1092 / 253.15) · (t + 273.15)
(This is expressed as absolute temperature: T [K], P = (0.1092 / 253.15) · T, Fahrenheit temperature: t_FIn terms of [° R], P = (0.1092 / 455.67) · (t_F+45.9.67))
become. For this reason, in the operating range from the lowest temperature of -20 ° C to the allowable maximum gas temperature, CF_ThreeIn order to keep the gas state without liquefying I and prevent the dielectric strength from decreasing even if the gas temperature changes, the CF in the transformer_ThreeI between the gas temperature t ° C. and the gas pressure PMPa
P <(0.1092 / 253.15). (T + 273.15)
(This is expressed as absolute temperature: T [K], P <(0.1092 / 253.15) · T, Fahrenheit temperature: t_FIn terms of [° R], P <(0.1092 / 455.67) · (t_F+45.9.67))
CF so that the relationship_ThreeIt can be seen that I 1 should be enclosed.
[0023]
Figure 5 shows CF as an insulation cooling medium for transformers installed indoors._ThreeIt is one Example of the operation method of the transformer at the time of using I, and is the case where the minimum temperature which guarantees the operation | movement prescribed | regulated to JEC-2200 is -5 degreeC.
[0024]
In this case, the minimum temperature has only changed from -20 ° C in the outdoor environment to -5 ° C._ThreeSince the saturation pressure of I at −5 ° C. is 0.1918 MPa, the CF is within the operating range from the lowest temperature of −5 ° C. to the allowable maximum gas temperature._ThreeIn order to keep the gas state without liquefying I and prevent the dielectric strength from decreasing even if the gas temperature changes, the CF in the transformer_ThreeI between the gas temperature t ° C. and the gas pressure PMPa
P <(0.1918 / 268.15). (T + 273.15)
(This is expressed as absolute temperature: T [K], P <(0.1918 / 268.15) · T, Fahrenheit temperature: t_F[° R], P <(0.1918 / 482.67) · (t_F+45.9.67))
CF so that the relationship_ThreeI may be enclosed.
[0025]
In addition, IEC and ANSI also specify the minimum temperature that guarantees the operation of the transformer. CF at the minimum temperature tmin ° C_ThreeIf the saturation pressure of I is PminMPa, the CF in the transformer_ThreeThe relationship between the gas temperature t of I and the gas pressure PMPa is
P <(Pmin / (tmin273.15)). (T + 273.15)
(This is expressed as absolute temperature: Tmin, T [K], P <(Pmin / Tmin) · T, Fahrenheit temperature: t_Fmin, t_FIn terms of [° R], P <(Pmin / (t_Fmin + 459.67)) ・ (t_F+45.9.67))
CF to satisfy_ThreeI may be enclosed.
[0026]
Figure 6 shows CF as an insulating cooling medium for transformers installed outdoors._ThreeIt is one Example of the operating method of the transformer at the time of using the mixture containing I, and is the case where the minimum temperature which guarantees the operation | movement prescribed | regulated to JEC-2200 is -20 degreeC. In this case, the maximum gas pressure of the mixture in the transformer in the operating range, that is, the pressure at the maximum allowable gas temperature is 0.2975 MPa (2 kg / cm²This is an example less than G). By doing so, the tank of the transformer can be free from the regulation of the second type pressure vessel.
[0027]
CF_ThreeCF is a mixture of I and other substances_ThreeI liquefaction is CF_ThreeI Unlike the single case, not the pressure in the transformer,_ThreeThe partial pressure of I must be evaluated. CF that becomes saturated vapor at -20 ℃_ThreeBetween the gas temperature t ° C. and the gas pressure PMPa as described above
P = (0.1092 / 253.15) · (t + 273.15)
There is a relationship. CF_ThreeFor mixtures of I and other substances, CF at a gas temperature of t ° C._ThreeI gas partial pressure P_CF3IIf this pressure is not reached, the operating range from the lowest temperature of −20 ° C. to the maximum allowable gas temperature_ThreeI liquefaction does not occur. for that reason,
CF_ThreeFor gas-insulated transformers with a mixture containing I as the insulating cooling medium, CF_ThreeI gas temperature t ° C and gas partial pressure P_CF3IBetween MPa
P_CF3I<(0.1092 / 253.15) · (t + 273.15)
(This is expressed in absolute temperature: T [K], P_CF3I<(0.1092 / 253.15) · T, Fahrenheit temperature: t_F[° R] represents P_CF3I<(0.1092 / 455.67) ・ (t_F+45.9.67))
CF so that the relationship_ThreeI may be enclosed.
[0028]
CF_ThreeCF of the mixture containing I_ThreeSubstances other than I are excellent in electrical insulation, nonflammable, non-toxic, have both global warming potential and ozone depletion potential of 0, and are inexpensive N₂Can be preferably used, but rare gas such as helium, neon, argon, xenon, or CO₂Other general purpose materials can be used. SF₆, C₂F₆, C_FourF₈It is possible to reduce the amount of use of these substances having a high global warming potential, although they are excellent in electrical insulation properties.
[0029]
CF_ThreeWhen another substance is added to I, CF_ThreeCompared to the case of I alone, the dielectric strength and the cooling capacity are improved, and the capacity and size of the transformer can be increased.
In order to further improve the dielectric strength and cooling capacity, the maximum gas pressure of the transformer in the operating range is 0.2975 MPa (2 kg / cm²G) CF to be more than_ThreeIt is also possible to enclose substances other than I 2. However, in that case, the tank of the transformer becomes the second type pressure vessel.
[0030]
Figure 7 shows CF as an insulating cooling medium for transformers installed indoors._ThreeIt is one Example of the operation method of the transformer at the time of using the mixture containing I, and is the case where the minimum temperature which guarantees the operation | movement prescribed | regulated to JEC-2200 is -5 degreeC. In this case, the same idea can be established just by changing the minimum temperature from -20 ° C to -5 ° C in the outdoor environment. In the operating range from the minimum temperature of -5 ° C to the allowable maximum gas temperature, CF_ThreeTo prevent I from liquefying, CF in the transformer_ThreeI gas temperature t ° C and gas partial pressure P_CF3IBetween
P_CF3I<(0.1918 / 268.15) · (t + 273.15)
(This is expressed in absolute temperature: T [K], P_CF3I<(0.1918 / 268.15) · T, Fahrenheit temperature: t_F[° R] represents P_CF3I<(0.1918 / 482.67) ・ (t_F+45.9.67))
CF so that the relationship_ThreeI may be enclosed.
[0031]
In addition, the CF at the minimum temperature tmin ° C is the minimum temperature that guarantees transformer operation with IEC and ANSI._ThreeWhen the saturation pressure of I is Pmin MPa, CF_ThreeCF in a transformer using a mixture containing I as an insulating cooling medium_ThreeI gas temperature t ° C and gas partial pressure P_CF3IThe relationship with MPa
P_CF3I<(Pmin / (tmin + 273.15)) · (t + 273.15)
(This is expressed as absolute temperature: Tmin, T [K]._CF3I<(Pmin / Tmin) · T, Fahrenheit temperature: t_Fmin, t_F[° R] represents P_CF3I<(Pmin / (t_Fmin + 459.67)) ・ (t_F+45.9.67))
CF to satisfy_ThreeI may be enclosed.
[0032]
Of the above-described equations, P <(0.1092 / 253.15) · (t + 273.15), P <(0.1918 / 268.15) · (t + 273.15), P <(Pmin / In (tmin + 273.15)) and (t + 273.15), CF_ThreeI gas pressure is 0.1013 MPa (atmospheric pressure) or more, 0.2975 MPa (2 kg / cm²G), and P_CF3I<(0.1092 / 253.15) · (t + 273.15), P_CF3I<(0.1918 / 268.15) · (t + 273.15), P_CF3I<(Pmin / (tmin + 273.15)) · (t + 273.15), CF_ThreeThe gas partial pressure of I is 0.1013 MPa (atmospheric pressure) or more, 0.2975 MPa (2 kg / cm²It may be less than G).
[0033]
The basis for this will be described with reference to FIG. As shown in FIG._ThreeThe saturation temperature (boiling point) of I at 0.1013 MPa (atmospheric pressure) is −22.5 ° C., which is lower than the minimum temperature −20 ° C. that guarantees the operation specified in JEC-2200 when installed outdoors. -200C which is the lowest temperature of -2200. 0.2975 MPa (2 kg / cm²Less than G) is a pressure that can avoid the regulation of the second type pressure vessel described in the embodiment. CF at -5 ° C, which is the lowest temperature that guarantees operation when JEC-2200 is installed indoors_ThreeThe saturation pressure of I is 0.1918 MPa, and the CF when the temperature rises from this state_ThreeI represents the relationship between gas temperature t ° C. and gas pressure PMPa.
P = (0.1918 / 268.15). (T + 273.15)
In this equation, when the temperature at which P = 0.2975 MPa is obtained, t = 142.8 ° C., and the gas temperature (about 100 ° C. maximum) used in the transformer can be sufficiently covered.
[0034]
Figure 8 shows CF as an insulating cooling medium for transformers._ThreeIs an example of a method of operating a transformer when I is used, and the CF at the minimum temperature tmin ° C. that guarantees the operation of the transformer_ThreeThe saturation pressure of I is Pmin MPa, and CF in the transformer_ThreeI gas temperature t ° C and gas pressure PMPa
P ≧ (Pmin / (tmin + 273.15)) · (t + 273.15)
(This is expressed as absolute temperature: Tmin, T [K], P ≧ (Pmin / Tmin) · T, Fahrenheit temperature: t_Fmin, t_FIn terms of [° R], P ≧ (Pmin / (t_Fmin + 459.67)) ・ (t_F+45.9.67))
This is the case. In this case, the CF in the transformer tank_ThreeCF when I gas temperature is low_ThreeI liquefies. The structure of the gas insulation transformer for preventing it is shown in FIG.
[0035]
In the figure, reference numeral 1 denotes a transformer tank. The transformer tank 1 contains an iron core 2 and a transformer 3 comprising a winding 3 wound around the iron core 2. For the insulating cooling medium 4 CF_ThreeI
P ≧ (Pmin / (tmin + 273.15)) · (t + 273.15)
It is sealed at such a pressure. The transformer tank 1 has as much CF as possible._ThreeA partition plate 5 is provided to partition the transformer tank 1 so that I flows in the iron core 2 and the winding 3, and the upper space 6 and the lower space 7 in the transformer tank 1 are separated so as not to communicate with each other. Yes. A cooler 10 is connected to the upper space 6 through the upper pipe 12. The lower space 7 is connected by a lower pipe 13 via a blower 11. CF below the transformer tank 1_ThreeAn electric heater 14 is provided as heating means for raising the temperature of I 2. CF on the top of the transformer tank 1_ThreeA temperature detector 20 for measuring the temperature of I 1 and a pressure detector 21 for measuring the pressure are provided. Further, a flow rate detector 22 that measures the flow rate of the cooling water 15 of the cooler 10, a flow rate control valve 23 that controls the flow rate, a wattmeter 24 that measures the input of the electric heater 14, and an input controller 25 that controls the input. Is installed. An arithmetic unit 26, which will be described in detail later, transmits a control signal for the input of the electric heater 14 to the input controller 25 while referring to the value of the wattmeter 24.
[0036]
With such a configuration, the electric heater 14 can generate CF._ThreeI can be heated to raise the temperature, or CF_ThreeThe temperature and pressure of I can be known by the temperature detector 20 and the pressure detector 21.
[0037]
As shown in FIG. 8, the CF of the rated load condition of the transformer_ThreeThe gas temperature of I is t_f℃, gas pressure P_fMPa, specific weight (density) is γkg / m^Three, Where R is the gas constant, CF in the gaseous state_ThreeI is

(This is absolute temperature: T_f, T [K], P = (P_f/ T_f・ T = γRT, Fahrenheit temperature: t_{F, f}, T_F[° R] represents P = (P_f/ (T_{F, f}+459.67)) ・ (t_F+459.67) = γR (t_F+45.9.67))
The state on the operating line of the gas temperature t ° C. and the gas pressure PMPa expressed as follows is maintained. This straight line and CF_ThreeHeated by heating means so that the temperature is equal to or higher than the intersection temperature of the vapor pressure curve of I_ThreeIf the gas temperature of I is maintained, even when the temperature is low and the entire transformer is not sufficiently warm, such as during startup, the CF_ThreeSince liquefaction of I does not occur, it is possible to prevent a decrease in dielectric strength.
[0038]
From the temperature detector 20 and the pressure detector 21 described above, CF_ThreeBecause I can know the temperature and pressure of I 4

And CF_ThreeThe temperature at the intersection of the vapor pressure curve of I, or the pressure, the value of both temperature and pressure, and the temperature obtained from the temperature detector 20, or the pressure obtained from the pressure detector 21, or the temperature detector 20 and the pressure detection Both the temperature and pressure obtained from the calculator 21 are compared by the calculator 26, and the wattmeter 24 from the calculator 26 is equal to or higher than the temperature of the intersection, or the pressure of the intersection, or both the temperature and pressure are equal to or greater than the value of the intersection. The operation shown in FIG. 8 can be performed by sending a control signal for the input of the electric heater 14 to the input controller 25 and controlling the heating amount while referring to the value of.
[0039]
The heating means does not necessarily need to be the electric heater 14, and a high-temperature fluid such as high-temperature water or water vapor may flow through a pipe provided in the lower part of the transformer tank 1, or cooling supplied to the cooler 10. Water 15 CF_ThreeThe hot fluid may be replaced only when heating of I is required. Further, the installation place of the heating means is not limited to the lower part of the transformer tank 1. For example, you may provide in the piping which makes the cooler 10 and the transformer tank 1 communicate.
[0040]
This driving method is CF_ThreeSince the gas pressure of I 2 can be increased, the density (specific weight) increases, the dielectric strength can be increased, and the transformer can be increased in pressure, capacity, and size.
[0041]
In this embodiment, the guided gas water cooling method is described, but the same effect can be obtained even when the cooling method is other methods.
[0042]
Fig. 9 shows CF as an insulating cooling medium for transformers._Three1 is an example of a method for operating a transformer when a mixture containing I is used, and the CF at the minimum temperature tmin ° C. that guarantees the operation of the transformer._ThreeThe saturation pressure of I is PminMPa, and CF in the transformer_ThreeI gas temperature t ° C and gas partial pressure P_CF3IMPa relationship
P_CF3I≧ (Pmin / (tmin + 273.15)) · (t + 273.15)
(This is expressed as absolute temperature: Tmin, T [K]._CF3I≧ (Pmin / Tmin) · T, Fahrenheit temperature: t_Fmin, t_F[° R] represents P_CF3I≧ (Pmin / (t_Fmin + 459.67)) ・ (t_F+45.9.67))
This is the case. CF_ThreeCF is a mixture of I and other substances_ThreeI liquefaction is CF_ThreeIt is sufficient to evaluate with the partial pressure of I. CF of the rated load condition of the transformer_ThreeI gas temperature t_f℃, gas partial pressure P_{f, CF3I}MPa, specific weight (density) is γkg / m^Three, If the gas constant is R,

(Where absolute temperature is T_f, T [K], P = (P_{f, CF3I}/ T_f・ T = γRT, Fahrenheit temperature: t_{F, f}, T_F[° R] represents P = (P_{f, CF3I}/ (T_{F, f}+459.67)) ・ (t_F+459.67) = γR (t_F+45.9.67))
And CF_ThreeI is heated by the heating means so as to be equal to or higher than the temperature of the intersection of the vapor pressure curves of I,_ThreeIf the gas temperature of the mixture containing I is kept at or above the saturation temperature, the CF can be used even when the temperature of the entire transformer is low, such as during startup._ThreeSince the mixture containing I is not liquefied, a decrease in dielectric strength can be prevented.
[0043]
This driving method is also CF_ThreeCF other than I_ThreeI The dielectric strength is improved as compared with the case of I alone, and the transformer can be increased in voltage, capacity, and size.
[0044]
FIG. 10 is a modification of the embodiment shown in FIG. 1, and is different from FIG. 1 in that it does not include an electric heater, a wattmeter, and an input controller, and other configurations are the same as those in FIG. .
[0045]
With such a configuration of the present embodiment, the gas temperature in the transformer tank 1 is used, for example, when starting a transformer in a cold region where the temperature is low or in the winter, or when restarting the transformer after a shutdown due to periodic inspection. Is equal to the saturation temperature, only the blower 11 is operated before the transformer itself is operated, and the insulating cooling medium 4 of the transformer tank 1 is CF._ThreeI is circulated and the CF in the transformer tank 1 is_ThreeCF until a temperature higher than the saturation temperature of I_ThreeThe transformer body can be operated when I is warmed to a temperature higher than the saturation temperature. CF in transformer tank 1_ThreeThe temperature and pressure of I can be known by the temperature detector 20 and the pressure detector 21 as in FIG.
[0046]
In the embodiment described above, CF_ThreeThe electric heater is used as the heating means for preventing the liquefaction of I 2. However, when the electric field is reduced by applying a low voltage to the winding instead of a predetermined voltage to warm the gas and the temperature becomes higher than the temperature at which liquefaction does not occur. An operation in which a predetermined voltage is applied is also possible, and the heating means includes the one that warms the gas in this way.
[0047]
【The invention's effect】
As described above, according to the present invention, CF_ThreeI or CF_ThreeIn the range of temperatures that guarantees the operation of gas-insulated static induction appliances using a mixture containing I as the insulating cooling medium, CF_ThreeAs a result of no liquefaction of I 2 and prevention of decrease in dielectric strength, it has excellent electrical insulation, nonflammability, almost no toxicity, and a global warming potential of CO₂Smaller, gas-insulated static induction machines with an ozone depletion coefficient of 0 can be operated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a gas-insulated transformer shown as an embodiment of the present invention.
FIG. 2 CF_ThreeI and SF₆It is a characteristic view which shows the measurement result of AC breakdown voltage.
FIG. 3 CF_ThreeIt is a characteristic view which shows the driving | operation range of the transformer which uses I as an insulation cooling medium.
FIG. 4 CF_ThreeIt is a characteristic view which shows the driving | operation range in case the transformer which uses I as an insulation cooling medium is installed outdoors, and minimum temperature is -20 degreeC.
FIG. 5 CF_ThreeIt is a characteristic figure which shows the driving | running range in case the transformer which uses I as an insulation cooling medium is installed indoors, and minimum temperature is -5 degreeC.
FIG. 6 CF_ThreeIt is a characteristic view which shows the driving | operation range in case the transformer which uses the mixture containing I as the insulation cooling medium is installed outdoors, and the minimum temperature is -20 degreeC.
FIG. 7 CF_ThreeIt is a characteristic view which shows the driving | operation range in case the transformer which uses the mixture containing I as the insulation cooling medium is installed indoors, and minimum temperature is -5 degreeC.
FIG. 8 CF_ThreeIt is a characteristic view which shows the operating range in the other Example of the transformer which uses I as an insulation cooling medium.
FIG. 9 CF_ThreeIt is a characteristic view which shows the operating range in the other Example of the transformer which uses the mixture containing I as the insulation cooling medium.
FIG. 10 is a configuration diagram of a transformer shown as another embodiment of the present invention.
FIG. 11 CF_ThreeIt is a characteristic view which shows the operating range of the vapor pressure curve of I and a low gas pressure transformer.
FIG. 12 is a configuration diagram showing a conventional gas-insulated transformer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transformer tank, 2 ... Iron core, 3 ... Winding, 4 ... Insulation cooling medium, 5 ... Partition plate, 6 ... Tank upper space, 7 ... Tank lower space, 10 ... Cooler, 11 ... Blower, 12 ... Upper Piping, 13 ... Lower piping, 14 ... Electric heater, 15 ... Cooling water, 20 ... Temperature detector, 21 ... Pressure detector, 22 ... Flow detector, 23 ... Flow control valve, 24 ... Wattmeter, 25 ... Input control Unit, 26 ... arithmetic unit.

Claims (7)

The contents of the electric appliance composed of an iron core and a winding wound around the iron core are housed in a tank together with an insulating cooling medium, and an insulating cooling medium is provided between the cooler disposed outside the tank and the tank via a pipe. circulating the CF ₃ I, when operated to raise the temperature of CF ₃ I by the heating means,
Relationship between CF ₃ I gas temperature t ° C. and gas pressure PMP expressed by specific weight (density) γ determined by the amount of CF ₃ I enclosed and gas constant R P = γR (t + 273.15)
And the pressure at the intersection of the vapor pressure curves of CF ₃ I, or the pressure, or the value of both temperature and pressure and the temperature of CF ₃ I obtained from the temperature detector, or the pressure of CF ₃ I obtained from the pressure detector, Alternatively, both the temperature and pressure of CF ₃ I obtained from the temperature detector and the pressure detector are compared, so that the temperature is equal to or higher than the temperature at the intersection, or the pressure at the intersection, or the temperature and pressure are equal to or higher than the value at the intersection. A method for operating a gas-insulated static induction device, wherein the heating means is controlled. The contents of the electric appliance composed of an iron core and a winding wound around the iron core are housed in a tank together with an insulating cooling medium, and an insulating cooling medium is provided between the cooler disposed outside the tank and the tank via a pipe. When the mixture containing CF ₃ I is circulated and the temperature of the mixture containing CF ₃ I is increased by heating means,
Relationship between CF ₃ I gas temperature t ° C. and gas partial pressure P _CF3I MPa expressed using specific weight (density) γ determined by the amount of CF ₃ I enclosed and gas constant R P _CF3I = γR (t + 273.15 )
And the temperature of the intersection of the vapor pressure curve of CF ₃ I, or the pressure, or the temperature of the mixture containing CF ₃ I obtained from both the temperature and pressure values and the temperature detector, or the CF ₃ I obtained by the pressure detector comparing both partial pressures of temperature and CF ₃ I of a mixture comprising a partial pressure or CF ₃ I obtained from the temperature detector and the pressure detector, the CF ₃ I obtained from the pressure of the mixture containing, in the intersection A method for operating a gas-insulated static induction device, wherein the heating means is controlled so as to be equal to or higher than a temperature, a pressure equal to or higher than a pressure at the intersection, or a temperature and a partial pressure equal to or higher than the value of the intersection. The contents of the electric appliance consisting of an iron core and a winding wound around the iron core are stored in a tank together with an insulating cooling medium, and provided between the cooler and the tank arranged outside the tank through a pipe. When operating by circulating CF ₃ I, which is an insulating cooling medium, using a blower
When the gas temperature in the tank is equal to the saturation temperature of the CF ₃ I, only the blower is operated before operating the electric appliance, and the CF ₃ I in the tank is circulated to saturate the CF ₃ I saturation temperature. A method for operating a gas-insulated static induction electric appliance, wherein the CF ₃ I is heated to a higher temperature, and the electric appliance is operated when the temperature becomes higher than a saturation temperature. The contents of the electric appliance consisting of an iron core and a winding wound around the iron core are stored in a tank together with an insulating cooling medium, and provided between the cooler and the tank arranged outside the tank through a pipe. When operating by circulating a mixture containing CF ₃ I as an insulating cooling medium by a blower that is
When the gas temperature in the tank is equal to the saturation temperature of the CF ₃ I, only the blower is operated before the electric appliance is operated, and the mixture containing the CF ₃ I in the tank is circulated to the CF ₃ I. A method for operating a gas-insulated static induction appliance, wherein the mixture containing CF ₃ I is warmed to a temperature higher than a saturation temperature of the gas, and the electric appliance is operated when the temperature becomes higher than the saturation temperature. An iron core, an electric content comprising a winding wound around the iron core, a tank for storing the electric content together with an insulating cooling medium, a cooler disposed outside the tank, and a space between the cooler and the tank. A gas-insulated static induction appliance that comprises a piping that communicates and circulates an insulating cooling medium between the cooler and the tank,
A gas-insulated static induction device characterized in that CF ₃ I is used as the insulating cooling medium, and at least a part of the gas-insulated static induction device includes heating means for raising the temperature of the CF ₃ I. An iron core, an electric content comprising a winding wound around the iron core, a tank for storing the electric content together with an insulating cooling medium, a cooler disposed outside the tank, and a space between the cooler and the tank. A gas-insulated static induction appliance that comprises a piping that communicates and circulates an insulating cooling medium between the cooler and the tank,
The insulation with use of CF ₃ I as the cooling medium, the temperature detector detects the temperature of the heating means and the CF ₃ I to raise the temperature of the CF ₃ I in at least a portion of the gas insulated stationary induction apparatus, or CF ₃ A gas-insulated static induction device comprising a pressure detector for detecting the pressure of I 1, or both of the temperature detector and the pressure detector. The insulating and cooling a medium CF ₃ I is claimed in claim 5 or 6, wherein the gas insulated stationary induction apparatus, characterized in that a mixture containing the CF ₃ I.

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