JP3550125B2 - Transmission line fault monitoring device - Google Patents

Description

Ａ相で１線地絡故障が発生したと仮定すると、同図（Ｂ）のように、各相の電圧はＶＡＧ＝０、ＶＢＧ、ＶＣＧとなるので、零相電圧Ｖｏ は式（２）で表される。

上部電圧センサ２ｕに誘導されるＡ相、Ｂ相、Ｃ相の電圧成分は、前記感度比を考慮するとＶＵＡＧ 、ＶＵＢＧ 、ＶＵＣＧ となるので、上部電圧センサ２ｕの出力電圧ＶＵＧはこれらの合成ベクトルとなり、式（３）で表される。
【００１７】

前記出力電圧ＶＵＧは各電力線に対するセンサ感度が各相で異なるため零相電圧Ｖｏ からずれている。しかし、このずれは前記出力電圧ＶＵＧから平常時の出力電圧ＶＵ （図２のＡ）を減算することによって補正でき、図２（Ｂ）の零相成分ＶＵｏが算出される。これをＡ相地絡の場合について示すと、前記の式（１）〜（３）を用いて次のように表わされる。
【００１８】

なお、ＶＡ を基準ベクトルとし、時計回りを負とした場合のＶＵ 、ＶＵＧ、Ｖｏ 、ＶＵｏの大きさおよび向きはつぎのようになる。
ＶＵ ＝０．７２（−１４゜）
ＶＵＧ＝０．９２（−１６９゜）
Ｖｏ ＝３．０（１８０゜）
ＶＵｏ＝１．６（１８０゜）
すなわち、Ａ相地絡の場合のセンサ２ｕの出力と正常時の同出力とのベクトル差であるＶＵｏは、Ａ相地絡の場合の零相電圧Ｖｏ に比例した電圧となる。
【００１９】
次に下部電圧センサ２ｄの出力電圧について説明する。図３には下部電圧センサ２ｄの各電力線Ａ〜Ｃに対する感度の比を０．３：０．５：１とした場合の電圧ベクトル図を示す。正常時に下部電圧センサ２ｄに誘導されるＡ相、Ｂ相、Ｃ相の電圧成分は、同図（Ａ）に示すように、感度比０．３：０．５：１．０を考慮するとＶＬＡ、ＶＬＢ、ＶＬＣとなる。下部電圧センサ２ｄの出力電圧ＶＬ は前記ベクトルＶＬＡ、ＶＬＢ、ＶＬＣの合成であるから、上部電圧センサの場合と同様の演算により、式（５）で表される。
【００２０】

Ａ相で１線地絡故障が発生すると、図３（Ｂ）に示すように、各相の電圧はＶＡＧ＝０、ＶＢＧ、ＶＣＧとなり、下部電圧センサ２ｄに誘導されるＡ相、Ｂ相、Ｃ相の電圧成分は前記感度比を考慮すると、ＶＬＡＧ 、ＶＬＢＧ ＶＬＣＧ となる。下部電圧センサ２ｄの出力電圧ＶＬＧはこれらの合成であるから、式（６）で表される。
【００２１】

前記出力電圧ＶＬＧは、上部電圧センサ２ｕの場合と同様に、感度が各相で異なるため零相電圧Ｖｏ からずれているが、つぎの式（７）に示すように、出力電圧ＶＬＧから平常時の出力電圧ＶＬ を減算した電圧ＶＬｏは零相電圧Ｖｏ に比例したものとなる。
【００２２】

上述のように、各電力線への相対感度が異なる上部電圧センサ２ｕと下部電圧センサ２ｄの、それぞれの故障時の出力電圧ベクトルから正常時の出力電圧ベクトルを減算して得られるＶＵｏとＶＬｏはほぼ同じ電圧ベクトルとなる。
【００２３】
また一般的に、電圧センサの各電力線に対する感度をα、β、γとすると、正常時に電圧センサから出力される電圧ＶＮ は式（８）で表わされる。
ＶＮ ＝α＊ＶＡ ＋β＊ＶＢ ＋γ＊ＶＣ ……（８）
Ａ相で地絡が発生した場合に電圧センサから出力される電圧ＶＧ は式（９）で表わされる。

地絡時の出力電圧ＶＧ から正常時の出力電圧ＶＮ を減算したＶｏ ’は式（１０）となる。
Ｖｏ ’＝ＶＧ −ＶＮ

式（１０）から、地絡時のセンサの電圧出力ベクトルから正常時の電圧出力ベクトルを減算することにより、電圧センサの各電力線への感度の相違とは無関係に零相電圧Ｖｏ に比例した電圧を得ることが出来ることが解る。
【００２４】
上記のように、減算することで各電圧センサの電力線に対する相対感度に依存せず零相電圧Ｖｏ に比例した電力電圧を得ることができるので、電圧センサの取付位置の調整は不要となる。又、４回線の場合も同様に他の回線の影響によらず零相電圧に比例した電圧を得ることができる。
【００２５】
次に２線地絡の場合について説明する。図４はＡ、Ｂ相地絡の故障点における電圧ベクトル図であり、同図の（Ａ）は上部電圧センサ２ｕに関するもの、（Ｂ）は下部電圧センサ２ｄに関するものである。Ａ、Ｂの２相が地絡した場合の零相電圧Ｖｏ はＶＣＧとなりＶＣ の１．５倍となることが知られており、Ａ相地絡の場合と同様に、各電力線に対するセンサ感度の差を考慮した上部電圧センサ２ｕの出力電圧ＶＵＡＢＧは式（１１）で表される。
【００２６】
ＶＵＡＢＧ＝０．２＊ＶＣＧ＝０．２＊１．５＊ＶＣ ＝０．３＊ＶＣ
またＶｏ ＝ＶＡＧ＋ＶＢＧ＋ＶＣＧ＝ＶＣＧ＝１．５ＶＣ 、
かつ（ＶＡＧ＝ＶＢＧ＝０）であるから、
ＶＵＡＢＧ＝０．２＊Ｖｏ …… （１１）
このＶＵＡＢＧ から、式（１）で表わされる正常時の電圧ＶＵ を減算して得られる電圧ＶＵｏは式（１２）で表される。
【００２７】

Ａ、Ｂ相地絡の場合はＣ相電圧しか生じていないため、前記の減算では、電圧ＶＵ が余分に補正してしまい、零相電圧Ｖｏ から位相がずれてしまう結果となる。
【００２８】
一方、下部電圧センサ２ｄの出力電圧ＶＬＡＢＧから、式（５）で表わされる正常時の電圧ＶＬ を減算した電圧ＶＬｏは下記の式（１３）で表わされ、上部センサの場合の電圧ＶＵｏと同様に零相電圧Ｖｏ からずれてしまう。

しかし、図４（Ａ）および（Ｂ）の対比から分るように、前記２つの電圧ベクトルＶＵｏとＶＬｏは零相電圧Ｖｏ を挟んで、互いに反対側へずれるから、電圧ＶＵｏとＶＬｏの平均をとれば零相電圧Ｖｏ に近似した電圧ベクトルＶＵＬｏ を算出することが可能となる。
【００２９】
上述したところから分かるように、ベクトルＶＵＬｏ を正確にゼロ相電圧Ｖｏ に一致させるためには、式（１２）と式（１３）の第１項の係数の絶対値を等しくする必要がある。式（１２）の第１の項の係数０．６は上部電圧センサ２ｕのＡ相に対する感度１からＢ相に対する感度０．４を引いた値であり、式（１３）の第１項の係数０．２は下部電圧センサ２ｄのＢ相に対する感度０．５からＡ相に対する感度０．３を引いた値である。それ故に、上部電圧センサ２ｕのＡ〜Ｃ相電力線に対する感度をα１、β１、γ１、下部センサ２ｄのＡ〜Ｃ相電力線に対する感度をα２、β２、γ２とすると、ＡＢ相地絡の場合にＶＵｏとＶＬｏの平均をとることによって零相電圧Ｖｏ に比例した電圧ベクトルを得るため、すなわち式（１２）および式（１３）の第１項の係数の絶対値を等しくするための各電圧センサ２ｕ、２ｄの設置位置は、
α１−β１＝β２−α２
を満足する位置となる。また、ＢＣ相地絡やＣＡ相地絡の場合に零相電圧Ｖｏ に比例した電圧ベクトルを得るための上部下部の電圧センサの設置位置は、それぞれつぎのようになる。
【００３０】
β１−γ１＝γ２−β２（ＢＣ地絡の場合の条件）
γ１−α１＝α２−γ２（ＣＡ地絡の場合の条件）
以上の解析より、次式の条件を満足する位置に上部および下部センサ２ｕ、２ｄを配置すればよいことが分る。
【００３１】
α１＋α２＝β１＋β２＝γ１＋γ２
つまり、どの２線地絡の場合でも誘導電圧を検出する上部および下部電圧センサ２ｕ、２ｄを、鉄塔内の異なる任意の箇所に２個設置し、各センサの出力電圧波形の平均をとることによって零相電圧に（近似的に）比例した電圧波形を得ることが出来る。したがって、本発明によれば電圧センサの取付位置の調整は不要となる。更に、図２（Ａ）から分かるように、正常時の上部電圧センサ２ｕの出力電圧ベクトルＶＵ の位相はＡ相電圧（一般的には、センサ感度の最も大きい相の電圧）のそれに近いので、正常時の上部電圧センサ２ｕの出力電圧ベクトルＶＵ の位相を基準とし、減算して得られた電圧ベクトルＶＵｏの位相を計測することで、Ｖｏ の位相角を近似的に算出することが出来る。
【００３２】
図４において、ＶＡ を基準ベクトルとし、時計回りを負とした場合の前記各ベクトルＶｏ 、ＶＵ 、ＶＵＡＢＧ、ＶＵｏ、ＶＬ 、ＶＬＡＢＧ、ＶＬｏ、ＶＵＬｏ の大きさおよび位相角はつぎの通りになる。前述のように、ベクトルＶＵ の位相角はＡ相電圧のそれに近いので、下記の位相角は近似的にベクトルＶＵ を基準とする位相角とみることができる。このような位相角を予め判定基準として準備しておくことにより、故障時に得られた位相角に基づいて１線地絡か２線地絡かの識別、および地絡した相の特定をすることができる。
【００３３】
Ｖｏ ＝１．５（１２０゜） ＶＵ ＝０．７２（−１４゜）
ＶＵＡＢＧ＝０．３（１２０゜） ＶＵｏ＝０．９５（１５３゜）
ＶＬ ＝０．６２（１３８゜） ＶＬｏ＝０．９２（１０９゜）
ＶＬＡＢＧ＝１．５（１２０゜） ＶＵＬｏ ＝０．９４（１３１゜）
次に、短絡故障の場合について説明する。図５にＡＢ短絡の場合の故障点における電圧ベクトル図を示す。同図（Ａ）は上部電圧センサ２ｕに関するもの、（Ｂ）は下部センサ２ｄに関するものである。ＡＢ短絡が発生すると、相電圧ＶＡＳ、ＶＢＳ は同じベクトルとなり、ＶＣＳは逆方向でＶＡＳの２倍の大きさを持つベクトルとなる。このため、上部および下部電圧センサ２ｕ、２ｄの各電力線に対する感度が等しければ、電圧センサの出力電圧は零となるが、本発明では、一般的に、前記両電圧センサの各電力線に対する感度は等しくならないから、出力電圧は零とならない。
【００３４】
ここでは上述のように、上部電圧センサ２ｕの感度比を１：０．４：０．２、下部電圧センサ２ｄの感度比を０．３：０．５：１と仮定しているから、上部電圧センサ２ｕの出力電圧ＶＵＡＢ 、下部電圧センサ２ｄの出力電圧ＶＬＡＢ は式（１４）で表わされる。

図５の（Ａ）および（Ｂ）からも分るように、ＶＵＡＢ はＶＡＳと同方向のベクトルとなり、ＶＬＡＢ はＶＣ と同方向のベクトルとなる。すなわち、短絡故障の場合も故障時の相電圧と同方向の電圧波形を、前記センサ出力に基づいて得ることが出来る。
【００３５】
また、上部および下部電圧センサ２ｕ、２ｄの出力電圧ベクトルＶＵＡＢ とＶＬＡＢ は互いに逆相となっており、正常時の各センサ出力を減算して得られる電圧ベクトルＶＵＳとＶＬＳも逆相となる。これらの電圧ベクトルはつぎの式（１５）で表される。

以上のように、本発明では、正常時に上部および下部電圧センサ２ｕ、２ｄから出力電圧が得られるように前記両センサを配置しておき、演算処理によって故障時の零相電圧を算出するようにしているため、短絡故障の場合には相電圧と同方向の電圧波形を得ることができるようになる。
【００３６】
次に故障種別の判別方法について説明する。
地絡故障の場合は、図２、図３、図４のＶＵｏ、ＶＬｏを対比すれば解るように、各電圧センサの故障時出力から正常時出力を減算して得られる減算電圧ベクトルＶＵｏおよびＶＬｏが（ほぼ）同相、または９０°以下となる。一方短絡故障の場合は、図５のように、各電圧センサの故障時出力から正常時出力を減算した電圧ベクトルＶＵＳおよびＶＬＳが（ほぼ）逆相となるので、短絡故障を地絡故障から判別することができる。又、２線地絡時の零相電圧Ｖｏ は短絡時の短絡相電圧の１．５倍になることが知られている。本実施例においても、地絡の場合の電圧センサ２ｕ、２ｄの検出電圧のベクトル量（図４のＶＵＬｏ ）は短絡の場合のそれ（図５のＶＵＳ又はＶＬＳ）の少なくとも１．５倍以上となるので、単にレベル比較をすることでも地絡か短絡かを判別できる。
【００３７】
さらに、下記方法で故障相も判定できる。地絡故障の場合は、得られた減算電圧ベクトル（ＶＵｏ又はＶＬ ｏ ）の位相角が零相電圧の位相角となるので、あらかじめＡ相地絡は１８０゜（Ａ相地絡時の零相電圧Ｖｏ の位相角）、ＡＢ相地絡は１２０゜（ＡＢ相地絡時の零相電圧Ｖｏ の位相角）等と、故障内容に対応して位相角を予め設定しておけば、これらの設定位相角と得られた減算電圧ベクトルのそれとを比較することによって故障相も判別可能となる。
【００３８】
３個の電圧センサを各相の電力線Ａ、Ｂ、Ｃの横にそれぞれ設置する場合も、以上に述べたのと同様の解析により、Ｂ相の横に設置した電圧センサ（図示せず）については、各電力線に対する感度をＡ相：Ｂ相：Ｃ相＝０．５：１：０．５と仮定すると、減算電圧ベクトルＶＭｏは下式（１６）で表わされる。

また前述のように、ＡおよびＣ相電力線の横に設置した電圧センサ２ｕ、２ｄの故障時の出力電圧から正常時の電圧を減算した差電圧ベクトルは式（１２）、（１３）で示される。式（１６）の第１項の係数が式（１２）の値より小さく式（１３）の値より大きい値となり、３つの減算電圧ベクトルＶＵｏ、ＶＬｏ、ＶＭｏの平均を求めることで零相電圧に比例した電圧を得ることが出来る。
【００３９】
図１０に本発明を適用した送電線故障監視装置の１実施例のブロック図を示す。なお電圧センサ２ｕおよび２ｄの出力処理は、各系列別に同じように行なわれるので、図では、繁雑化を避けるために、電圧センサの出力処理系列については電圧センサ２ｕに関する構成のみを示し、電圧センサ２ｄに関する構成は図示を省略している。上部電圧センサ２ｕの出力は遅延回路３１ｂおよび減算回路３２ｂに供給される。減算回路３２ｂには遅延回路３１ｂの出力も転送され、上部電圧センサ２ｕの出力から遅延回路３１ｂの出力が減ぜられ、得られた差信号は故障成分メモリ４１ｂに供給される。前記差信号は、明らかなように、正常値からの変動分として現れる故障成分に相当する故障成分波形データである。遅延回路３１ｂの出力は正常波形メモリ４２ｂに保存される。
【００４０】
故障発生検出器４４ｂは、前述したように、故障判定のために予め設定された設定値（レベル）４３ｂと前記故障成分波形データとを比較し、後者が前者を設定数サイクルの間以上継続して超えたときは故障信号４６ｂを発生する。これに応答して、前記故障成分波形データが故障成分メモリ４１ｂに、また演算処理前の検出電圧波形データ（すなわち、故障発生前の正常時デ−タ）が正常波形メモリ４２ｂにそれぞれ記憶される。前記各メモリとしては、例えばＦＩＦＯ（Ｆｉｒｓｔ−Ｉｎ−Ｆｉｒｓｔ−Ｏｕｔ）メモリが利用できる。また、故障成分波形データは減算回路の出力から直接取り込んでもよい。この場合、メモリ４２ｂへの前記検出電圧波形データの記憶量をメモリ４１ｂへの前記故障成分波形データの記憶量の２倍程度にするのが望ましい。例えば、前記故障成分波形データを５サイクル分、前記検出電圧波形データを１０サイクル分記憶するのが好都合である。なお、前記正常時波形データとしては、平常時の各センサの検出電圧波形データを（半）固定的に記憶したものを用いてもよい。
【００４１】
ピークレベル検出器５１ｂは、前記故障成分メモリ４１ｂに記憶され故障成分波形データを供給されてそのピーク値を検出し、これを故障種別判定部６０に転送する。位相計測器５２ｂは、故障成分メモリ４１ｂから転送される故障成分波形データの前記正常波形メモリ４２ｂからの信号に対する位相差、すなわち電圧センサの正常時の電圧波形データを基準にした故障成分波形データの位相を計測し、これを故障種別判定部６０に転送する。故障種別判別部６０は、地絡／短絡故障判定のためのそれぞれの設定値６３を供給され、前記ピークレベル検出器５１ｂおよび／または位相計測器５２ｂからの信号を各設定値と対比して、前述のような故障種別を判定し決定する。
【００４２】
図６〜９は本実施例を種々の形式の送電線鉄塔に適用した場合の電圧センサの配置例を示すもので、図６は水平配列送電線の場合、図７は１回線垂直配列送電線の場合、図８は三角配列送電線の場合、図９は４回線装架鉄塔の場合である。いずれの場合も、ある１つの相に対する電圧センサの感度が、他の相に対する感度よりも大きくなるように、少なくとも１つの電圧センサを設置すれば、送電線の故障時における電圧センサの出力電圧波形から正常時の出力電圧波形を減算することで、零相電圧を検出できるし、減算した波形同士の位相比較、予め設定された位相に対する位相比較や予め設定されたレベルに対するレベル比較を、前述と同様に行なうことによって、送電線の故障種別又は故障相の判別が可能となる。
【００４３】
本発明を平行２回線同相配列の送電鉄塔に適用した第２実施例における各センサの配置例を図１１に示す。同図において、図１と同一の符号は同一または同等部分を表わす。この実施例は、図１に示した実施例に、最上段の電力線の上側および最下段電力線の下側にそれぞれ設置され、棒状コアにコイルを巻いて構成された１対の地絡センサ３ｕおよび３ｄと、Ｂ相電力線を結ぶ線上に設置され、その感度が前記地絡センサ３ｕ、３ｄに比べて数分の１と低く設定された短絡センサ４と、これらの各種センサからの出力情報を伝送され、これに基づいて故障種別および故障点方向を判定する故障方向判定器５と、なるべくは判定結果が遠方からでも確認できるような（高い）位置に設置された表示器６とを追加した構成である。本実施例によれば、故障種別の判定をより正確に行なえるのみならず、本実施例装置の設置位置から見た故障点の方向をも判定することができる。
【００４４】
なお、前記電圧センサ２ｕ、２ｄは特定の相電圧を取り出すため、特定相の影響が最も強くなる（特定相に対する検出感度が最も大きくなる）ような位置に置かれる。本実施例では、Ａ相及びＣ相電力線の間にそれぞれ設置し、電圧センサ２ｕ、２ｄの出力電圧としては、ほぼＡ相又はＣ相の電圧に比例した電圧が得られるようにしているが、Ｂ相電力線の間に置いてもかまわない。また各電圧センサの設置位置は、前述の実施例の場合と同じように、鉄塔１の両側の対応相位置にある１対の電線（Ａ１とＡ２又はＢ１とＢ２など）を結ぶ線上であればどこでもよい。また後述するように、各電圧センサの出力は各別に独立に処理され、個々の出力に基づいて故障判断が行なわれる。
【００４５】
地絡センサ３ｕ、３ｄはそれらの合成出力（加算出力）が地絡故障時に、零相電流に比例した電流値となるように、既知の手法にしたがって、それらの設置位置が若干調整されている。また短絡センサ４は、コアの長手方向をＢ相の方に向けてＢ相電力線の間に設置され、ＡＢ短絡の場合はＡ相電流を、ＢＣ短絡の場合はＣ相電流を、またＣＡ短絡の場合はＣ相、Ａ相電流の合成電流を計測して各相に流れる短絡電流を検出する。
【００４６】
故障・方向判定器５の回路構成を図１２〜１４に示す。故障・方向判定器５は各センサ毎に設けた波形デ−タ演算部３０、波形デ−タ記憶部４０、およびレベル・位相計測部５０、故障種別判別部６０を含み、さらに故障点方向判定部７０、遮断検出部８０および故障情報表示部９０を含むように構成されている。
【００４７】
波形デ−タ演算部３０では、各地絡センサ３ｕ、３ｄの出力を加算する加算回路３３ａや、他の電圧センサ２ｕ、２ｄ、短絡センサ４の検出出力である各電圧波形データと、前記各電圧波形デ−タを遅延回路３１ａ〜ｃで設定サイクル数だけ遅延させた電圧波形データとの差を減算回路３２ａ〜ｃでそれぞれ演算（減算又は加算）する。前記演算で得られた差デ−タは、明らかなように、平常時からの変動分として現れる故障成分に相当する故障成分波形データである。なお電圧センサ２ｕおよび２ｄの出力処理は、前述の実施例と同じように、各系列別に同じように行なわれるので、図１２では、繁雑化を避けるために、電圧センサの出力処理系列については電圧センサ２ｕに関する構成のみを示し、電圧センサ２ｄに関する構成は図示を省略している。
【００４８】
波形デ−タ記憶部４０では、前記各センサに対して予め設定された、故障判定のための設定値（レベル）４３ａ〜ｃと前記故障成分波形データとを故障発生検出器４４ａ〜ｃで比較し、後者が前者を設定数サイクルの間以上継続して超えたとき、故障発生検出器４４ａ〜ｃが故障信号４６ａ〜ｃを発生する。これに応答して、前記故障成分波形データが故障成分メモリ４１ａ〜ｃに、また演算処理前の各センサの検出電圧波形データ（すなわち、故障発生前の正常時デ−タ）が正常波形メモリ４２ａ〜ｃにそれぞれ記憶される。前記各メモリとしては、例えばＦＩＦＯ（Ｆｉｒｓｔ−Ｉｎ−Ｆｉｒｓｔ−Ｏｕｔ）メモリが利用できる。また、故障成分波形データは減算回路の出力から直接取り込んでもよい。この場合、メモリ４２ａ〜ｃへの前記検出電圧波形データの記憶量をメモリ４１ａ〜ｃへの前記故障成分波形データの記憶量の２倍程度にするのが望ましい。例えば、前記故障成分波形データを５サイクル分、前記検出電圧波形データを１０サイクル分記憶するのが好都合である。なお、前記正常時波形データとしては、平常時の各センサの検出電圧波形データを（半）固定的に記憶したものを用いてもよい。
【００４９】
前記のように抽出される故障成分波形データは、地絡センサ３ｕ、３ｄでは零相電流成分であり、短絡センサ４では特定相に流れる短絡電流成分（本実施例の場合はＡＢ短絡の場合はＡ相電流、ＢＣ短絡の場合はＣ相電流、またＣＡ短絡の場合はＣ相、Ａ相電流の合成に比例した電流）である。また電圧センサ２ｕ（２ｄ）では、地絡時には上および下センサの両方共零相電圧が得られ、短絡時は最も影響が大きい相（すなわち、感度が最も高い相；本実施例では、それぞれＡ相およびＣ相）の電圧に比例した波形が得られる。
【００５０】
レベル・位相計測部５０の各ピークレベル検出器５１ａ〜ｃは、対応する前記故障成分メモリ４１ａ〜ｃのそれぞれに記憶され故障成分波形データのピーク値Ｊ、Ｋ、Ｌをそれぞれ検出する。また電圧センサ系列のレベル・位相計測部では、演算前ピークレベル検出器５３および演算前位相計測器５４で、正常波形メモリ４２ｂに記憶されている演算処理前の検出電圧波形データＢ（すなわち、故障発生前の正常時デ−タ）のピークレベルＭと、演算処理前の検出電圧波形データＢを基準とした故障発生時の演算処理前の検出電圧波形データの位相Ａをそれぞれ検出する。さらに、各位相計測器５２ａ〜ｃは、それぞれ対応する故障成分波形データの位相の前記正常時デ−タＢの位相に対する位相差、すなわち電圧センサの正常時の電圧波形データＢを基準にした位相を計測し、それぞれの故障成分の位相Ｅ、Ｆ、Ｇとして出力する。
【００５１】
故障種別判別部６０は、電圧センサ系列および短絡センサ系列の各ピークレベル検出器５１ｂ、ｃの出力信号Ｋ、Ｌおよび位相計測器５２ｂ、ｃの出力信号Ｆ、Ｇ、ならびに故障判定のためのそれぞれの設定値６３を供給される。そして、▲１▼短絡センサ系列のピークレベル検出器５１ｃより得られた故障レベルＬが設定レベを越え、かつ電圧センサ系列のピークレベル検出器５１ｂの出力である故障レベルＫが設定レベル以下である場合、および▲２▼電圧センサ系列のいずれかの電圧センサの出力から得られる故障位相差Ｆ（位相計測器５２ｂの出力）が設定位相より大きい場合の、いずれかの場合には短絡故障と判定する。さらに▲３▼電圧センサ系列および短絡センサ系列の故障レベルＫ、Ｌすなわち故障成分レベルがいずれも設定値以上である場合は２線地絡と判定する。
【００５２】
一方、▲１▼短絡センサ系列のピークレベル検出器５１ｃより得られた故障レベルＬが設定レベルより小さく、且つ電圧センサ系列のピークレベル検出器５１ｂの出力である故障レベルＫが設定レベル以上である場合、または▲２▼電圧センサ系列のいずれかの電圧センサの出力から得られる故障位相差Ｆが設定位相より小さい場合には地絡故障と判別する。同時に、故障種別判定部６０は短絡センサ４の位相計測器５２ｃからの故障位相Ｇおよびピークレベル検出器５１ｃからの故障レベルＬを出力をする。
【００５３】
上記のように故障種別を判定する理由は次のとおりである。高抵抗接地系の送電系統においては、短絡電流の方が地絡電流よりも数倍大きく、また電圧センサ２ｕ、２ｄの故障成分として現れる地絡時の零相電圧と短絡時の短絡電圧とでは、零相電圧の方が短絡電圧より大きい。このような事実に基づいて、短絡センサ４の故障成分Ｌがその設定レベルを超えるか、または電圧センサ２ｕ、２ｄの故障成分Ｋがその設定レベル以下であれば短絡故障と判定し、一方、短絡センサ４の故障成分Ｌがその設定レベルより小さく、且つ電圧センサ２ｕ、２ｄの故障成分Ｋがその設定レベル以上であれば地絡故障とする。
【００５４】
なお、図示例のように電圧センサが複数個設置されている場合は、複数個のすべての電圧センサの故障成分として、地絡故障の場合には零相電圧が、また短絡故障の場合には、各センサが最も影響を受ける相電圧が現れる。このため、短絡故障の場合の複数個の電圧センサの故障成分の位相差を事前に計算して設定値を決めておき、この設定値より複数個の上記電圧センサの故障成分の位相差が小さい場合は地絡故障、大きい場合は短絡故障と判別することができる。
【００５５】
また、電圧センサの検出波形の特定相からの位相ずれを算出し、そのずれ分によって故障成分の位相を補正し、その位相に基づいて故障種別を判別する方法も可能である。すなわち、上部電圧センサ２ｕからはＡ相に近い位相の出力電圧ベクトルが検出され、また前記上部電圧センサ２ｕの出力電圧のＡ相からのずれ角（補正分）は算出することができるので、故障時の出力電圧ベクトルから正常時の出力電圧ベクトルを減算して得られる減算電圧ベクトルの、正常時の出力電圧ベクトル位相を基準とした位相ずれを計測した後補正して零相電圧の位相角を求める。零相電圧の位相角は、１線地絡の場合は６０°、１８０°、３００°に近く、２線地絡の場合は０°、１２０°、２４０°に近いことが知られているので、前記位相角から故障種別を判別することができる。
【００５６】
故障点方向判定部７０では、例えば図１５に示すように、地絡事故時の故障電流Ｉ１ 、Ｉ２ の向きが故障点Ｘを境にして逆向きとなる事実に基づいて、故障種別判別部６０が地絡故障と判定した場合には、位相比較器７１において地絡センサ系列の位相計測器５２ａの故障位相出力Ｅと電圧センサ系列の位相計測器５２ｂから得られた故障位相出力Ｆとの位相比較を行なう。そして、前記２つの故障位相出力Ｅ、Ｆが同位相の場合には、本実施例装置（例えば、図１５のＰ１地点に設置される）より線路の一端側（例えば、ＳＳ２側）での故障と判定される。図１５のＰ２地点に設置された故障監視装置も同じ構成を有するから、ここでの前記２つの故障位相出力Ｅ、Ｆは逆位相となり、故障地点は本故障監視装置より他端側（すなわち、ＳＳ１側）と判定される。
【００５７】
反対に、故障種別判別の結果が短絡故障の場合には、位相比較器７２において短絡センサ系列の故障位相信号Ｇと電圧センサ系列の位相計測器５２ｂから得られた故障位相信号Ｆとの位相比較を行い、同位相の場合には本装置より線路の一端側での故障、逆位相の場合には本装置より他端側での故障と判定する。方向判定結果はそれぞれの表示器９２、９４に接続された出力線Ｌ１ 、Ｌ２ 上に供給され、上記の故障点方向判定に用いた故障レベル及び故障位相の各出力Ｅ〜Ｇ、Ｊ〜Ｌは故障情報表示部９０に出力され、記憶される。なお、電圧センサ系列のピークレベル検出器５１ｂから得られた故障レベルＫが設定レベルより小さい場合は、前記故障位相出力Ｆの代りに、故障時の演算処理前の電圧センサ系列の検出電圧波形データの位相計測器５４の出力Ａを用いてもよい。
【００５８】
遮断検出部８０では、当該送電線の故障が判定されて回線が遮断された場合は、それから一定時間後に故障電流がなくなって送電電圧が低下する事実に着目し、故障発生から一定時間後に地絡センサ系列のピークレベル検知器５１ａから得られる故障レベルＪ（短絡センサのピークレベル検知器５１ｃから得られる故障レベルＬで代用できる）が故障発生時より小さくなったこと、および電圧センサ系列の演算処理前の検出電圧波形データ（演算前ピークレベル検出器５３の出力Ｍ）が平常時より低下したことの論理積に基づいて、当該送電線路の遮断検出信号を出力する。前記遮断検出信号によって、方向判定結果をそれぞれの表示器９２、９４に供給する出力線Ｌ１ 、Ｌ２ に介在されたスイッチＳＥ１ 、ＳＥ２ が閉成されて１端側または他端側表示器９２、９４のいずれか一方に、上記の故障点方向判定結果に基づく予定の表示がされる。
【００５９】
故障情報表示部９０は、図１４に示すように、内部に時計９６を具備し、故障が発生した時刻を計時、記憶すると共に、そのときに、故障種別判定部６０や故障点方向判定部７０で使用した各種位相、レベルデ−タや判定結果なども記憶し、必要に応じて表示できるようにする。これらのデータは、故障が短時間内に複数回発生したような場合に、電気所で記録された故障発生時刻と照合して、複数箇所に設置された同種装置の時間的整合性を確認しながら、総合的な故障地点の判定や故障原因の分析のための情報として利用できる。またこの場合、電圧センサ２ｕ、２ｄの検出電圧が商用周波数であることを利用し、その検出波形（例えば、ゼロクロス点）で前記内部時計９６を予定時間ごとに同期補正する時刻修正手段９８を設けておけば、時計９６の時刻ずれを実質上なくすることもできる。
【００６０】
図１６は、平行２回線で逆相配列とされた送電線に本発明を適用した第３実施例の要部を示す概略図である。上部および下部短絡センサ４ｕ、４ｄがそれぞれ最上段および最下段の送電線対を結ぶ線上に設置され、電圧センサ２が中段の送電線対を結ぶ線上に設置されている点で相違する外は、図１１と同じであり、同図と同一の符号は同一部分を表わす。なお各短絡センサ４ｕ、４ｄの棒状コアは大地に対してほぼ垂直になるように設置される。図１７には、図１６の逆相配列の片端電源系において、地点ＸでＡ１・Ｂ１相短絡故障が発生した場合に、各送電線に流れる短絡電流の様子を示す。ＩＳ１は電源端ＳＳ１から下側の故障回線Ａ１，Ｂ１を通って直接故障点Ｘに流れる短絡電流であり、ＩＳ２は上側の健全回線Ａ２，Ｂ２から電気所ＳＳ２を通って故障点Ｘに流れる短絡電流である。上部短絡センサ４ｕは電力線Ａ１に近いため，電力線Ａ１に流れる短絡電流に比例した出力電圧ＶＳＵを故障成分として発生する。一方、下部短絡センサ４ｄは電力線Ａ２に近いためそこに流れる短絡電流に比例した出力電圧ＶＳＬ を故障成分として検出する。各短絡センサ４ｕ、４ｄからみた電力線の架設順序（位相）が短絡センサを挟んで右側と左側とで反対になっているため、故障点Ｘよりも電源側のＰ１地点では、上部短絡センサ４ｕから得られる故障成分電圧ＶＳＵと下部短絡センサ４ｕから得られる故障成分電圧ＶＳＬとは互いに逆方向となるのに対し、故障点Ｘよりも負荷側のＰ２地点では上部および下部短絡センサ４ｕ、４ｄから得られる故障成分電圧ＶＳＵ、ＶＳＬは同方向となる。
【００６１】
したがって、このような逆相配列送電線に本発明を適用する場合は、故障点方向判定部７０において上下の各短絡センサ２ｕ、２ｄから得られる故障成分電圧の位相を比較し、同相か逆相かにしたがって、短絡センサ設置の位置から見た故障点方向を判定することができる。また、上記の各短絡電流の間にはＩＳ１＞ＩＳ２の関係があるため、上下短絡センサ２ｕ、２ｄの故障成分電圧の合成電圧の位相は、Ｐ１地点ではＡ１の位相が、またＰ２点でもＡ１の位相が得られる。したがって、上下短絡センサの故障成分の合成値の位相を短絡電流の位相として電圧センサの電圧波形又は故障成分の位相と比較すれば、同相か逆相かにしたがって、前述と同様に、短絡センサの設置位置から見た故障点方向を判定することもできる。
【００６２】
【発明の効果】
本発明によれば、送電線路の任意の箇所の鉄塔に、地絡センサ、短絡センサ及び電圧センサの少なくとも１つを取付ける際の設置位置や感度調整を簡単化（場合によっては、不要化）して所要時間や労力、熟練度を少なくすることができ、演算処理によって容易に零相電圧やセンサ出力の故障成分を得ることができるため、各種センサの設計の余裕度が増し、コスト低減も容易である。また、短絡故障時も電圧センサによって相電圧を検出できるので、電圧センサの演算処理前後の波形やレベルを比較することによって、故障種別又は故障相が容易に判別できるようになる。さらにこれらセンサを装備した鉄塔に故障・方向判定器の外に表示器をも取付けて置けば、両端電源線路や片端電源線路において、本装置単独で、当該送電線で発生した故障点の方向を判定・表示することが可能となる。また故障発生時刻、各センサ出力の故障成分のレベルや位相、故障種別、故障点の方向などを記憶するメモリを準備しておけば、故障が短時間の間に続けて起ったような場合に、事故の分別や故障解析などが可能になる。
【図面の簡単な説明】
【図１】本発明を平行２回線同相配列の標準的な送電線鉄塔に適用した第１実施例における電圧センサの配置例を示す概略側面図である。
【図２】図１における上部電圧センサの出力を示す電圧ベクトル図であり、（Ａ）は正常時、（Ｂ）はＡ相地絡故障時を示す。
【図３】図１における下部電圧センサの出力を示す電圧ベクトル図であり、（Ａ）は正常時、（Ｂ）はＡ相地絡故障時を示す。
【図４】図１におけるＡ、Ｂ相地絡時の電圧ベクトル図であり、（Ａ）は上部電圧センサの出力、（Ｂ）は下部電圧センサの出力を示す。
【図５】図１におけるＡＢ相短絡時の電圧ベクトル図であり、（Ａ）は上部電圧センサの出力、（Ｂ）は下部電圧センサの出力を示す。
【図６】本発明を水平配列送電線鉄塔に適用した他の実施例における電圧センサの配置例を示す概略側面図である。
【図７】本発明を垂直配列送電線鉄塔に適用したさらに他の実施例における電圧センサの配置例を示す概略側面図である。
【図８】本発明を三角配列送電線鉄塔に適用した別の実施例における電圧センサの配置例を示す概略側面図である。
【図９】本発明を４回線送電線鉄塔に適用したさらに別の実施例における電圧センサの配置例を示す概略側面図である。
【図１０】本発明の第１実施例のブロック図である。
【図１１】本発明を平行２回線同相配列の標準的な送電線鉄塔に適用した第２実施例における各種センサの配置例を示す概略側面図である。
【図１２】図１３、１４と共に、前記第２実施例のハード構成を示すブロック図である。
【図１３】図１２、１４と共に、前記第２実施例のハード構成を示すブロック図である。
【図１４】図１２、１３と共に、前記第２実施例のハード構成を示すブロック図である。
【図１５】前記第２実施例による故障点方向判別動作を説明するための概念図である。
【図１６】本発明を平行２回線逆相配列の送電線鉄塔に適用した第３実施例における各種センサの配置例を示す概略側面図である。
【図１７】図１６に示した送電線に相短絡事故が生じた場合の短絡電流の状態を示す概念図である。
【図１８】送電線に地絡事故が生じた場合の問題点を説明するための概略図である。
【符号の説明】
１…送電鉄塔 ２ｕ、ｄ…上部、下部電圧センサ ３ｕ、ｄ…上部、下部地絡センサ ４…短絡センサ ４ｕ、ｄ…上部、下部短絡センサ ５…故障／方向判別器 ６…表示器 ３０…波形データ演算部 ３１ａ〜ｃ…遅延回路 ３２ａ〜ｃ…減算回路 ３３ａ…加算回路 ４０…波形データ記憶部 ４１ａ〜ｃ…故障成分メモリ ４２ａ〜ｃ…正常波形メモリ ４４ａ〜ｃ…故障発生検出器 ４３ａ〜ｃ、６３…設定値 ５０…レベル・位相計測部 ５１ａ〜ｃ…ピークレベル検出器 ５２ａ〜ｃ…位相計測器 ６０…故障種別判別部 ７０…故障点判定部７１、７２…位相比較器 ８０…遮断検出部 ９０…故障情報表示部 ９２、９４…表示器 ９６…時計 ９８…時刻修正手段 ＶＡ 、ＶＢ 、ＶＣ …相電圧ベクトル Ｖｏ …零相電圧ベクトル ＶＵ 、ＶＬ …上部および下部電圧センサの正常時の出力電圧ベクトル ＶＵｏ、ＶＬｏ、ＶＵＳ、ＶＬＳ…減算電圧ベクトル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission line fault monitoring device, in particular, detects a zero-phase voltage and a fault phase voltage based on the output of a voltage sensor, a ground fault sensor, a short-circuit sensor, and the like configured from an electrode body installed on a transmission line tower, Further, the present invention relates to an apparatus for determining the type and phase of a transmission line fault and the direction of a fault point viewed from the sensor installation position based on this.
[0002]
[Prior art]
As a method of detecting a zero-phase voltage generated when a ground fault occurs in a transmission line, a plurality of electrode units conventionally installed on a transmission line tower (a vector sum of induced voltages is output according to a transmission voltage of each transmission line). It is known to obtain a zero-sequence voltage by adjusting the installation position of a voltage sensor composed of. For example, in Japanese Utility Model Laid-Open Publication No. 60-41866 proposed by the present applicant, the potentials of a plurality of electrode bodies are combined or the potential of a single electrode body becomes zero or zero when the voltage of each phase of the power line is equal. The electric capacity and distance between each power line and the electrode body are adjusted in advance so as to be very small, and the voltage generated between the electrode body and the earth when an accident occurs in the transmission line is detected, so that the zero-phase Voltage is being detected.
[0003]
Further, as a method for determining a faulty section of a transmission line, the following is conventionally known.
(1) In the case of a system in which one end of a transmission line is a neutral point high-resistance ground power supply and the other end is a load, the current of an overhead ground wire that flows due to induction of a fault current flowing in the transmission line when a failure occurs in the transmission line Is detected, and the failure direction is determined by comparing the detection level with the set value level.
(2) In the case of the above-mentioned transmission system, a zero-phase current and a zero-phase voltage flowing in the transmission line are detected by a ground fault sensor and a voltage sensor installed on a transmission line tower at an arbitrary point on the transmission line, and when both are in phase. Determines that there is a fault section on the load side of the tower.
(3) When both ends of the transmission line are neutral point high-resistance ground power supplies, the current flowing through the overhead ground line is measured at arbitrary plural points on the transmission line, and the measured data is measured using the overhead ground line (for example, OPGW). Is transmitted as a transmission path to a central monitoring device installed in an electric station such as a substation, and a section where the level or phase of the measurement data greatly changes is determined as a failed section.
[0004]
[Problems to be solved by the invention]
In the zero-phase voltage detection method by adjusting the capacitance of the electrode body described above, the voltage sensor including a plurality of or single electrode bodies and the distance from each transmission line, that is, the installation position are adjusted, and the voltage sensor is synthesized in a normal state. Although it is necessary to make the output zero or minimum, since the combined output depends on each arm length and arm spacing of the tower supporting the transmission line, there are many interrelated adjustment items, and the combined output is set to zero or zero. Minimization requires skill and a great deal of time and effort. In particular, in the case of a tower having four lines, there is a problem that it is extremely difficult to reduce the combined output to zero because a transmission voltage other than the line to be detected also affects the transmission line. Furthermore, since the adjustment is performed so that only the zero-sequence voltage is detected, the output of the voltage sensor becomes zero in the case of a short-circuit failure in which no zero-sequence voltage is generated, and the phase voltage generated at the time of short-circuit cannot be detected. There is also.
[0005]
In the above example (1), the magnitude of the ground fault current flowing through the overhead ground wire does not change much near the fault point, and the detection level becomes almost the same before and after the fault point. If a failure occurs in the vicinity of the installation, there is a possibility that the direction of the failure point may be erroneous. Further, it cannot be applied to a power supply system in which both ends are grounded to a neutral point and a system in which the power supply at both ends is switched. Further, as shown in FIG. 18, even if a fault occurs in a section other than the line section SS1-SS2, when the power supply is on the SS1 side, a fault current flows from SS1 to SS2 to the fault point X, and There is a problem that the transmission line fault direction detectors P1 to P3 installed between SS2 operate.
[0006]
In the case of the above (2), when installing the sensor in the power transmission tower, it takes a lot of time and time to adjust the sensor position and / or sensitivity so that only the zero-phase current and the zero-phase voltage are detected. Requires experience and effort. As in the case of the above (1), it cannot be applied to a power supply system in which both ends are grounded to a neutral point or a system in which the power supply at both ends is switched. Further, even in the case of a fault other than the line, a fault current and a fault voltage are generated, resulting in a malfunction.
[0007]
In the case of the above (3), a system configuration for performing data transmission by connecting the sensor attached to the overhead ground wire and the central monitoring device with an optical fiber in the OPGW is required, and a large-scale device and a large amount of accompanying device are required. Requires equipment costs.
[0008]
An object of the present invention is to use a voltage sensor consisting of an electrode body installed on a transmission line tower for detecting a fault voltage of a transmission line, easily and without adjustment, to a zero-phase voltage or a zero-phase voltage generated at the time of a ground fault of the transmission line. It is an object of the present invention to provide a transmission line fault monitoring device capable of obtaining a phase voltage generated at the time of a short circuit and determining the type of an accident that has occurred in the transmission line and the direction of the accident point.
[0009]
Another object of the present invention is to simplify installation adjustment of a sensor installed in a power transmission tower, and to apply the present invention to a system in which power is supplied to both ends or to a system in which power is switched at both ends. The purpose of the present invention is to provide a transmission line fault monitoring device capable of determining the type of a fault and the direction of an accident point.
[0010]
[Means for Solving the Problems]
In the transmission line tower, a voltage sensor equipped to generate an output even when the transmission line is normal detects an induced voltage proportional to the transmission voltage, and detects the phase and level of the voltage sensor output voltage at the time of an accident. At least one of the failure types and the failure phase are determined by collating at least one of them with a predetermined criterion. A subtracted voltage vector, which is a difference between the output of the voltage sensor at the time of occurrence of an accident and the output at the time of normal operation, that is, a fault voltage component or its average value can be used instead of the output voltage.
[0011]
In addition to the voltage sensor, a ground fault current flowing in the transmission line, a ground fault sensor and a short-circuit current sensor for detecting a short-circuit current are provided, and when an accident occurs, the phase of an output voltage or a failure component obtained from these sensors, At least one of a level, an average value of the levels, and the like is collated with a predetermined criterion to determine at least one of a failure type, a failure phase, and a direction of the failure point viewed from the sensor installation point.
[0012]
In particular, in the case of a parallel two-line reversely arranged transmission line, when a short-circuit fault occurs in the transmission line based on the output of a pair of short-circuit sensors arranged on or near the line connecting the upper and lower power lines of the transmission line The phase of the fault current component is calculated, and this is compared with a judgment criterion prepared in advance to determine the direction of the fault point viewed from the sensor installation point. Further, based on the correlation between the combined current phase of the fault current component obtained from the output of the short-circuit sensor and the phase of the output of the voltage sensor or the phase of the subtracted voltage vector, the direction of the short-circuit point viewed from these sensor installation points is determined. I do.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a voltage sensor mounting state when the present invention is applied to a standard transmission tower having a parallel two-line in-phase arrangement. Two three-phase power lines A1, B1, C1, A2, B2, and C2 are suspended from the respective arms of the tower 1 via insulators. Upper and lower voltage sensors 2u and 2d which are constituted by electrode bodies and detect an induced voltage from each power line are respectively installed on a line connecting power lines A1 and A2 and a line connecting power lines C1 and C2.
[0014]
In this case, the induced (output) voltage obtained by each of the upper and lower voltage sensors 2u and 2d is proportional to the reciprocal of the distance from the power line. FIG. 2 shows a voltage vector diagram when the ratio of the sensitivity of the upper voltage sensor 2u to each phase power line is 1: 0.4: 0.2. The vectors VA, VB, VC have balanced three-phase voltages applied to the power lines A1, B1, C1, A2, B2, C2, and all power lines are at the position of A1 (that is, each power line and the sensor 2u and A, B, and C phase voltage components exerted on the voltage sensor 2u when it is assumed that the distances are equal.
[0015]
The voltage component induced in the upper voltage sensor 2u in the normal state is such that the sensitivity ratio of the A phase, the B phase, and the C phase is 1: 0.4: 0.2 as described above, and FIG. ), VUA; VUB; VUC = 1.0: 0.4: 0.2. Since the output voltage VU of the upper voltage sensor 2u is a composite vector of the voltage components VUA, VUB, and VUC, it is expressed by equation (1). In this specification, the symbol * indicates multiplication.
[0016]

Assuming that a one-line ground fault has occurred in the A phase, the voltages of the respective phases are VAG = 0, VBG, and VCG as shown in FIG. 2B, and the zero-phase voltage Vo is given by the equation (2). expressed.

The voltage components of A-phase, B-phase, and C-phase induced by the upper voltage sensor 2u become VUAG, VUBG, and VUCG in consideration of the sensitivity ratio. Therefore, the output voltage VUG of the upper voltage sensor 2u becomes a composite vector of these. , Equation (3).
[0017]

The output voltage VUG deviates from the zero-phase voltage Vo because the sensor sensitivity to each power line differs in each phase. However, this deviation can be corrected by subtracting the normal output voltage VU (A in FIG. 2) from the output voltage VUG, and the zero-phase component VUo in FIG. 2B is calculated. When this is shown for the case of the A-phase ground fault, it is expressed as follows using the above equations (1) to (3).
[0018]

The magnitudes and directions of VU, VUG, Vo, and VUo when VA is a reference vector and clockwise is negative are as follows.
VU = 0.72 (-14 °)
VUG = 0.92 (-169 °)
Vo = 3.0 (180 °)
VUo = 1.6 (180 °)
That is, VUo, which is the vector difference between the output of the sensor 2u in the case of the A-phase ground fault and the same output in the normal state, is a voltage proportional to the zero-phase voltage Vo in the case of the A-phase ground fault.
[0019]
Next, the output voltage of the lower voltage sensor 2d will be described. FIG. 3 shows a voltage vector diagram when the sensitivity ratio of the lower voltage sensor 2d to each of the power lines A to C is 0.3: 0.5: 1. The voltage components of the A-phase, B-phase, and C-phase induced by the lower voltage sensor 2d in the normal state are VLA when the sensitivity ratio is 0.3: 0.5: 1.0 as shown in FIG. , VLB, and VLC. Since the output voltage VL of the lower voltage sensor 2d is a combination of the vectors VLA, VLB, and VLC, it is expressed by equation (5) by the same calculation as that of the upper voltage sensor.
[0020]

When a one-line ground fault occurs in the A phase, as shown in FIG. 3B, the voltage of each phase becomes VAG = 0, VBG, VCG, and the A, B, and B phases guided to the lower voltage sensor 2d. Considering the sensitivity ratio, the C-phase voltage component is VLAG, VLBG VLCG. Since the output voltage VLG of the lower voltage sensor 2d is a combination of these, it is expressed by equation (6).
[0021]

As in the case of the upper voltage sensor 2u, the output voltage VLG deviates from the zero-phase voltage Vo because the sensitivity is different in each phase. However, as shown in the following equation (7), the output voltage VLG is normally lower than the output voltage VLG. The voltage VLo obtained by subtracting the output voltage VL is proportional to the zero-phase voltage Vo.
[0022]

As described above, VUo and VLo obtained by subtracting the normal output voltage vector from the fault output voltage vector of each of the upper voltage sensor 2u and the lower voltage sensor 2d having different relative sensitivities to the respective power lines are substantially equal to each other. The same voltage vector results.
[0023]
Generally, when the sensitivity of the voltage sensor to each power line is α, β, and γ, the voltage VN output from the voltage sensor in a normal state is represented by Expression (8).
VN = α * VA + β * VB + γ * VC (8)
The voltage VG output from the voltage sensor when a ground fault occurs in the A phase is represented by Expression (9).

Vo ′ obtained by subtracting the normal output voltage VN from the output voltage VG at the time of ground fault is given by the following equation (10).
Vo '= VG-VN

By subtracting the normal voltage output vector from the sensor voltage output vector at the time of ground fault from equation (10), the voltage proportional to the zero-phase voltage Vo is obtained regardless of the difference in sensitivity of the voltage sensor to each power line. It can be understood that can be obtained.
[0024]
As described above, by subtracting, a power voltage proportional to the zero-phase voltage Vo can be obtained without depending on the relative sensitivity of each voltage sensor to the power line, so that the adjustment of the mounting position of the voltage sensor becomes unnecessary. Similarly, in the case of four lines, a voltage proportional to the zero-phase voltage can be obtained regardless of the influence of the other lines.
[0025]
Next, the case of a two-line ground fault will be described. 4A and 4B are voltage vector diagrams at the fault points of the A and B phase ground faults. FIG. 4A is for the upper voltage sensor 2u, and FIG. 4B is for the lower voltage sensor 2d. It is known that the zero-phase voltage Vo when two phases A and B are grounded becomes VCG and becomes 1.5 times VC, and similarly to the case of the A-phase grounded, the sensor sensitivity of each power line is reduced. The output voltage VUABG of the upper voltage sensor 2u in consideration of the difference is represented by Expression (11).
[0026]
VUABG = 0.2 * VCG = 0.2 * 1.5 * VC = 0.3 * VC
Vo = VAG + VBG + VCG = VCG = 1.5VC,
And (VAG = VBG = 0),
VUABG = 0.2 * Vo (11)
The voltage VUo obtained by subtracting the normal voltage VU represented by the equation (1) from the VUABG is represented by the equation (12).
[0027]

In the case of the A-phase and B-phase ground faults, only the C-phase voltage is generated. Therefore, the above-described subtraction results in an extra correction of the voltage VU, resulting in a phase shift from the zero-phase voltage Vo.
[0028]
On the other hand, a voltage VLo obtained by subtracting the normal voltage VL represented by the equation (5) from the output voltage VLABG of the lower voltage sensor 2d is represented by the following equation (13), and is the same as the voltage VUo in the case of the upper sensor. Deviates from the zero-phase voltage Vo.

However, as can be seen from the comparison between FIGS. 4A and 4B, the two voltage vectors VUo and VLo are shifted to opposite sides with respect to the zero-phase voltage Vo, so that the average of the voltages VUo and VLo is calculated. Then, a voltage vector VULo approximate to the zero-phase voltage Vo can be calculated.
[0029]
As can be seen from the above description, in order for the vector VULo to exactly match the zero-phase voltage Vo, it is necessary to make the absolute values of the coefficients of the first term of the equations (12) and (13) equal. The coefficient 0.6 in the first term of the equation (12) is a value obtained by subtracting the sensitivity 0.4 for the B phase from the sensitivity 1 for the A phase of the upper voltage sensor 2u, and the coefficient of the first term in the equation (13). 0.2 is a value obtained by subtracting the sensitivity 0.3 for the A phase from the sensitivity 0.5 for the B phase of the lower voltage sensor 2d. Therefore, if the sensitivity of the upper voltage sensor 2u to the AC phase power lines is α1, β1, γ1 and the sensitivity of the lower sensor 2d to the AC phase power lines is α2, β2, γ2, VUo And VLo to obtain a voltage vector proportional to the zero-phase voltage Vo, that is, to equalize the absolute value of the coefficient of the first term of the equations (12) and (13). The installation position of 2d
α1-β1 = β2-α2
Is satisfied. The positions of the upper and lower voltage sensors for obtaining a voltage vector proportional to the zero-phase voltage Vo in the case of a BC phase ground fault or a CA phase ground fault are as follows.
[0030]
β1-γ1 = γ2-β2 (condition for BC ground fault)
γ1-α1 = α2-γ2 (condition for CA ground fault)
From the above analysis, it can be seen that the upper and lower sensors 2u and 2d should be arranged at positions satisfying the following condition.
[0031]
α1 + α2 = β1 + β2 = γ1 + γ2
In other words, two upper and lower voltage sensors 2u and 2d for detecting an induced voltage in any two-line ground fault are installed at different arbitrary positions in a steel tower, and the average of output voltage waveforms of each sensor is obtained. A voltage waveform that is (approximately) proportional to the zero-phase voltage can be obtained. Therefore, according to the present invention, the adjustment of the mounting position of the voltage sensor becomes unnecessary. Further, as can be seen from FIG. 2A, the phase of the output voltage vector VU of the upper voltage sensor 2u in normal operation is close to that of the A-phase voltage (generally, the voltage of the phase having the highest sensor sensitivity). By measuring the phase of the voltage vector VUo obtained by subtracting the phase of the output voltage vector VU of the upper voltage sensor 2u in a normal state, the phase angle of Vo can be approximately calculated.
[0032]
In FIG. 4, the magnitudes and phase angles of the vectors Vo, VU, VUABG, VUo, VL, VLABG, VLo, and VULo when VA is a reference vector and clockwise is negative are as follows. As described above, since the phase angle of the vector VU is close to that of the A-phase voltage, the following phase angle can be approximately regarded as a phase angle based on the vector VU. By preparing such a phase angle as a criterion in advance, it is possible to identify a single-wire ground fault or a two-wire ground fault based on the phase angle obtained at the time of failure, and to specify the phase in which the ground fault occurred. Can be.
[0033]
Vo = 1.5 (120 °) VU = 0.72 (−14 °)
VUABG = 0.3 (120 °) VUo = 0.95 (153 °)
VL = 0.62 (138 °) VLo = 0.92 (109 °)
VLABG = 1.5 (120 °) VULo = 0.94 (131 °)
Next, a case of a short-circuit failure will be described. FIG. 5 shows a voltage vector diagram at a failure point in the case of AB short circuit. FIG. 7A relates to the upper voltage sensor 2u, and FIG. 7B relates to the lower sensor 2d. When an AB short circuit occurs, the phase voltages VAS and VBS have the same vector, and the VCS has a vector having a magnitude twice as large as VAS in the opposite direction. For this reason, if the sensitivity of each of the upper and lower voltage sensors 2u and 2d to each power line is equal, the output voltage of the voltage sensor becomes zero. However, in the present invention, generally, the sensitivity of each of the two voltage sensors to each power line is equal. Therefore, the output voltage does not become zero.
[0034]
Here, as described above, it is assumed that the sensitivity ratio of the upper voltage sensor 2u is 1: 0.4: 0.2 and the sensitivity ratio of the lower voltage sensor 2d is 0.3: 0.5: 1. The output voltage VUAB of the voltage sensor 2u and the output voltage VLAB of the lower voltage sensor 2d are expressed by Expression (14).

As can be seen from FIGS. 5A and 5B, VUAB is a vector in the same direction as VAS, and VLAB is a vector in the same direction as VC. That is, even in the case of a short-circuit fault, a voltage waveform in the same direction as the phase voltage at the time of the fault can be obtained based on the sensor output.
[0035]
Also, the output voltage vectors VUAB and VLAB of the upper and lower voltage sensors 2u and 2d are in opposite phases, and the voltage vectors VUS and VLS obtained by subtracting the respective sensor outputs in the normal state also have opposite phases. These voltage vectors are expressed by the following equation (15).

As described above, in the present invention, both sensors are arranged so that output voltages can be obtained from the upper and lower voltage sensors 2u and 2d in a normal state, and a zero-phase voltage at the time of failure is calculated by an arithmetic processing. Therefore, in the case of a short circuit fault, a voltage waveform in the same direction as the phase voltage can be obtained.
[0036]
Next, a method of determining a failure type will be described.
In the case of a ground fault, as can be understood by comparing VUo and VLo in FIGS. 2, 3 and 4, subtracted voltage vectors VUo and VLo obtained by subtracting the normal output from the fault output of each voltage sensor. Is (almost) in-phase, or 90 ° or less. On the other hand, in the case of a short-circuit fault, as shown in FIG. 5, the voltage vectors VUS and VLS obtained by subtracting the normal output from the fault output of each voltage sensor have (almost) opposite phases, so that the short-circuit fault is determined from the ground fault. can do. It is also known that the zero-phase voltage Vo at the time of a two-wire ground fault becomes 1.5 times the short-circuit phase voltage at the time of short-circuit. Also in the present embodiment, the vector amount (VULo in FIG. 4) of the detected voltage of the voltage sensors 2u and 2d in the case of a ground fault is at least 1.5 times as large as that in the case of a short circuit (VUS or VLS in FIG. 5). Therefore, it is possible to determine whether a ground fault or a short circuit occurs simply by comparing the levels.
[0037]
Further, the failure phase can be determined by the following method. In the case of a ground fault, the phase angle of the obtained subtracted voltage vector (VUo or VL o) becomes the phase angle of the zero-phase voltage. The phase angle of the voltage Vo) and the AB phase ground fault are 120 ° (the phase angle of the zero-phase voltage Vo at the time of the AB phase ground fault). By comparing the set phase angle with that of the obtained subtracted voltage vector, a faulty phase can also be determined.
[0038]
When three voltage sensors are installed beside the power lines A, B, and C of each phase, the voltage sensor (not shown) installed beside the B phase is also analyzed by the same analysis as described above. Assuming that the sensitivity to each power line is A phase: B phase: C phase = 0.5: 1: 0.5, the subtraction voltage vector VMo is expressed by the following equation (16).

As described above, the difference voltage vector obtained by subtracting the normal voltage from the output voltage at the time of failure of the voltage sensors 2u and 2d installed beside the A and C phase power lines is expressed by the equations (12) and (13). . The coefficient of the first term of the equation (16) is smaller than the value of the equation (12) and larger than the value of the equation (13), and the average of the three subtracted voltage vectors VUo, VLo, VMo is calculated to reduce the zero-phase voltage. A proportional voltage can be obtained.
[0039]
FIG. 10 shows a block diagram of one embodiment of the transmission line fault monitoring device to which the present invention is applied. Note that the output processing of the voltage sensors 2u and 2d is performed in the same manner for each system. Therefore, in the figure, in order to avoid complication, only the configuration related to the voltage sensor 2u is shown for the output processing system of the voltage sensor. The configuration relating to 2d is not shown. The output of the upper voltage sensor 2u is supplied to a delay circuit 31b and a subtraction circuit 32b. The output of the delay circuit 31b is also transferred to the subtraction circuit 32b, the output of the delay circuit 31b is subtracted from the output of the upper voltage sensor 2u, and the obtained difference signal is supplied to the fault component memory 41b. As is apparent, the difference signal is fault component waveform data corresponding to a fault component that appears as a variation from a normal value. The output of the delay circuit 31b is stored in the normal waveform memory 42b.
[0040]
As described above, the failure occurrence detector 44b compares the set value (level) 43b preset for failure determination with the failure component waveform data, and the latter continues the former over a set number of cycles or more. Otherwise, a failure signal 46b is generated. In response to this, the fault component waveform data is stored in the fault component memory 41b, and the detected voltage waveform data before the arithmetic processing (ie, the normal data before the occurrence of the fault) is stored in the normal waveform memory 42b. . As each of the memories, for example, a FIFO (First-In-First-Out) memory can be used. Further, the fault component waveform data may be taken directly from the output of the subtraction circuit. In this case, it is desirable that the storage amount of the detected voltage waveform data in the memory 42b is about twice as large as the storage amount of the failure component waveform data in the memory 41b. For example, it is convenient to store the fault component waveform data for 5 cycles and the detected voltage waveform data for 10 cycles. As the normal-time waveform data, data in which the detected voltage waveform data of each sensor in a normal state is (half) fixedly stored may be used.
[0041]
The peak level detector 51b is supplied with the fault component waveform data stored in the fault component memory 41b, detects the peak value thereof, and transfers the detected peak value to the fault type determination unit 60. The phase measuring device 52b calculates the phase difference between the fault component waveform data transferred from the fault component memory 41b and the signal from the normal waveform memory 42b, that is, the fault component waveform data based on the normal voltage waveform data of the voltage sensor. The phase is measured and transferred to the failure type determination unit 60. The failure type determination unit 60 is supplied with the respective set values 63 for ground fault / short circuit failure determination, compares the signal from the peak level detector 51b and / or the phase measurement device 52b with each set value, The failure type as described above is determined and determined.
[0042]
6 to 9 show arrangement examples of voltage sensors when the present embodiment is applied to various types of power transmission towers. FIG. 6 shows a case of a horizontally arranged transmission line, and FIG. 8 shows the case of a triangular array transmission line, and FIG. 9 shows the case of a four-circuit tower. In any case, if at least one voltage sensor is installed so that the sensitivity of the voltage sensor for one phase is higher than the sensitivity for the other phase, the output voltage waveform of the voltage sensor at the time of transmission line failure By subtracting the normal output voltage waveform from, the zero-phase voltage can be detected, and the phase comparison between the subtracted waveforms, the phase comparison with a preset phase, and the level comparison with a preset level are described above. By performing in the same manner, it becomes possible to determine the fault type or the fault phase of the transmission line.
[0043]
FIG. 11 shows an example of the arrangement of sensors in a second embodiment in which the present invention is applied to a power transmission tower having a parallel two-line in-phase arrangement. In the figure, the same reference numerals as those in FIG. 1 represent the same or equivalent parts. This embodiment is different from the embodiment shown in FIG. 1 in that a pair of a ground fault sensor 3u and a pair of ground fault sensors 3u, which are installed above the uppermost power line and below the lowermost power line, respectively, are formed by winding coils around a rod-shaped core. 3d and a short-circuit sensor 4 whose sensitivity is set to be a fraction of lower than that of the ground fault sensors 3u and 3d, and which transmits output information from these various sensors. A fault direction judging device 5 for judging a fault type and a fault point direction based on this, and a display device 6 installed at a (high) position so that the judgment result can be confirmed from a distance as much as possible are added. It is. According to the present embodiment, it is possible not only to more accurately determine the failure type, but also to determine the direction of the failure point viewed from the installation position of the apparatus of the present embodiment.
[0044]
Since the voltage sensors 2u and 2d take out a specific phase voltage, the voltage sensors 2u and 2d are placed at positions where the influence of the specific phase is the strongest (the detection sensitivity for the specific phase is the highest). In the present embodiment, the voltage sensors 2u and 2d are provided between the A-phase and C-phase power lines, respectively, so that the output voltages of the voltage sensors 2u and 2d can be substantially proportional to the A-phase or C-phase voltage. It may be placed between the B-phase power lines. In addition, as in the case of the above-described embodiment, the installation position of each voltage sensor is on a line connecting a pair of electric wires (such as A1 and A2 or B1 and B2) at corresponding phase positions on both sides of the tower 1. Anywhere. As will be described later, the output of each voltage sensor is independently processed separately, and a failure determination is made based on each output.
[0045]
The installation positions of the ground fault sensors 3u and 3d are slightly adjusted according to a known method so that their combined output (added output) becomes a current value proportional to the zero-phase current when a ground fault occurs. . The short-circuit sensor 4 is disposed between the B-phase power lines with the longitudinal direction of the core facing the B-phase, and outputs an A-phase current in the case of an AB short-circuit, a C-phase current in the case of a BC short-circuit, and a CA short-circuit. In the case of (1), the combined current of the C-phase and A-phase currents is measured to detect the short-circuit current flowing in each phase.
[0046]
12 to 14 show the circuit configuration of the fault / direction determiner 5. The fault / direction determining unit 5 includes a waveform data calculating unit 30, a waveform data storage unit 40, a level / phase measuring unit 50, and a fault type determining unit 60 provided for each sensor. It is configured to include a unit 70, a cutoff detection unit 80, and a failure information display unit 90.
[0047]
The waveform data calculating unit 30 includes an adder circuit 33a for adding the outputs of the short-circuit sensors 3u and 3d, the voltage waveform data as detection outputs of the other voltage sensors 2u and 2d and the short-circuit sensor 4, and the respective voltages. The difference between the waveform data and the voltage waveform data delayed by the set number of cycles by the delay circuits 31a to 31c is calculated (subtracted or added) by the subtraction circuits 32a to 32c. As is clear, the difference data obtained by the above calculation is fault component waveform data corresponding to a fault component appearing as a variation from normal. Since the output processing of the voltage sensors 2u and 2d is performed in the same manner for each system as in the above-described embodiment, in order to avoid complication, FIG. Only the configuration relating to the sensor 2u is shown, and the configuration relating to the voltage sensor 2d is not shown.
[0048]
In the waveform data storage unit 40, the fault occurrence detectors 44a to 44c compare set values (levels) 43a to 43c for fault determination, which are preset for each of the sensors, with the fault component waveform data. However, when the latter continuously exceeds the former for a set number of cycles or more, the failure occurrence detectors 44a to 44c generate failure signals 46a to 46c. In response to this, the fault component waveform data is stored in the fault component memories 41a to 41c, and the detected voltage waveform data of each sensor before the arithmetic processing (that is, the normal data before the occurrence of the fault) is stored in the normal waveform memory 42a. To c. As each of the memories, for example, a FIFO (First-In-First-Out) memory can be used. Further, the fault component waveform data may be taken directly from the output of the subtraction circuit. In this case, it is preferable that the storage amount of the detected voltage waveform data in the memories 42a to 42c is about twice as large as the storage amount of the fault component waveform data in the memories 41a to 41c. For example, it is convenient to store the fault component waveform data for 5 cycles and the detected voltage waveform data for 10 cycles. As the normal-time waveform data, data in which the detected voltage waveform data of each sensor in a normal state is (half) fixedly stored may be used.
[0049]
The fault component waveform data extracted as described above is a zero-phase current component in the ground fault sensors 3u and 3d, and a short-circuit current component flowing in a specific phase in the short-circuit sensor 4 (in the case of the AB short-circuit in the present embodiment, A-phase current, C-phase current for BC short-circuit, and C-phase current for CA short-circuit). In the voltage sensor 2u (2d), a zero-phase voltage is obtained for both the upper and lower sensors at the time of a ground fault, and the phase having the largest influence (ie, the phase having the highest sensitivity; (Phase and C phase).
[0050]
The peak level detectors 51a to 51c of the level / phase measuring unit 50 detect the peak values J, K, and L of the fault component waveform data stored in the corresponding fault component memories 41a to 41c, respectively. In the level / phase measuring unit of the voltage sensor series, the pre-calculation peak level detector 53 and the pre-calculation phase measuring device 54 detect the pre-computation detected voltage waveform data B (that is, the fault voltage) stored in the normal waveform memory 42b. The peak level M of the normal data before occurrence and the phase A of the detected voltage waveform data before the arithmetic processing when a failure occurs based on the detected voltage waveform data B before the arithmetic processing are detected. Further, each of the phase measuring devices 52a to 52c calculates a phase difference between the phase of the corresponding fault component waveform data and the phase of the normal data B, that is, the phase based on the normal voltage waveform data B of the voltage sensor. Are measured and output as phases E, F, and G of the respective fault components.
[0051]
The failure type determination unit 60 includes output signals K and L of the peak level detectors 51b and c of the voltage sensor series and the short-circuit sensor series, output signals F and G of the phase measurement units 52b and c, respectively, and failure determination. Is supplied. (1) The failure level L obtained from the short-circuit sensor series peak level detector 51c exceeds the set level, and the failure level K output from the voltage sensor series peak level detector 51b is equal to or lower than the set level. In the case of (2), when the failure phase difference F (the output of the phase measuring device 52b) obtained from the output of any one of the voltage sensors of the voltage sensor series is larger than the set phase, in any case, it is determined that the short-circuit failure has occurred. I do. (3) If both the failure levels K and L, that is, the failure component levels of the voltage sensor series and the short-circuit sensor series are equal to or higher than the set values, it is determined that a two-wire ground fault occurs.
[0052]
On the other hand, (1) the failure level L obtained from the short-circuit sensor series peak level detector 51c is smaller than the set level, and the failure level K, which is the output of the voltage sensor series peak level detector 51b, is equal to or greater than the set level. In this case, or if (2) the failure phase difference F obtained from the output of any one of the voltage sensors in the voltage sensor series is smaller than the set phase, it is determined that a ground fault has occurred. At the same time, the failure type determination unit 60 outputs the failure phase G from the phase measuring device 52c of the short-circuit sensor 4 and the failure level L from the peak level detector 51c.
[0053]
The reason for determining the failure type as described above is as follows. In a transmission system of a high-resistance grounding system, the short-circuit current is several times larger than the ground-fault current, and the zero-phase voltage at the time of a ground fault and the short-circuit voltage at the time of a short-circuit appearing as a failure component of the voltage sensors 2u and 2d. , The zero-phase voltage is higher than the short-circuit voltage. Based on such a fact, if the fault component L of the short-circuit sensor 4 exceeds the set level or the fault component K of the voltage sensors 2u and 2d is lower than the set level, it is determined that a short-circuit fault has occurred. If the fault component L of the sensor 4 is smaller than the set level and the fault component K of the voltage sensors 2u and 2d is equal to or higher than the set level, it is determined that a ground fault has occurred.
[0054]
In the case where a plurality of voltage sensors are installed as in the illustrated example, a zero-sequence voltage in the case of a ground fault and a fault component in the case of a short-circuit fault, as a failure component of all the plurality of voltage sensors. , The phase voltage at which each sensor is most affected appears. For this reason, the phase difference between the fault components of the plurality of voltage sensors in the case of a short-circuit fault is calculated in advance to determine a set value, and the phase difference between the fault components of the plurality of voltage sensors is smaller than the set value. In this case, a ground fault can be determined, and when it is large, a short-circuit fault can be determined.
[0055]
It is also possible to calculate the phase shift of the detected waveform of the voltage sensor from a specific phase, correct the phase of the fault component based on the shift, and determine the fault type based on the phase. That is, an output voltage vector having a phase close to the A-phase is detected from the upper voltage sensor 2u, and a deviation angle (correction amount) of the output voltage of the upper voltage sensor 2u from the A-phase can be calculated. The phase difference of the subtracted voltage vector obtained by subtracting the normal output voltage vector from the normal output voltage vector is measured based on the normal output voltage vector phase, and then corrected to obtain the zero phase voltage phase angle. Ask. It is known that the phase angle of the zero-phase voltage is close to 60 °, 180 °, and 300 ° for a one-line ground fault, and is close to 0 °, 120 °, and 240 ° for a two-wire ground fault. The type of failure can be determined from the phase angle.
[0056]
In the fault point direction determining unit 70, as shown in FIG. 15, for example, based on the fact that the directions of the fault currents I1 and I2 at the time of the ground fault are opposite from the fault point X as a boundary, the fault type determining unit 60 Is determined to be a ground fault, the phase comparator 71 compares the phase of the fault phase output E of the phase detector 52a of the ground fault sensor series with the fault phase output F obtained from the phase meter 52b of the voltage sensor series. Make a comparison. When the two fault phase outputs E and F have the same phase, a fault at one end (for example, SS2 side) of the line from the apparatus of this embodiment (for example, installed at the point P1 in FIG. 15). Is determined. Since the fault monitoring device installed at the point P2 in FIG. 15 also has the same configuration, the two fault phase outputs E and F here have opposite phases, and the fault point is located on the other end of the fault monitoring device (ie, SS1).
[0057]
Conversely, if the result of the fault type determination is a short-circuit fault, the phase comparator 72 compares the phase of the fault phase signal G of the short-circuit sensor series with the fault phase signal F obtained from the phase sensor 52b of the voltage sensor series. In the case of the same phase, it is determined that the fault is at one end of the line from the present device, and when the phases are opposite, it is determined that the fault is at the other end of the line. The direction determination result is supplied to output lines L1 and L2 connected to the respective indicators 92 and 94. The outputs E to G and J to L of the fault level and the fault phase used for the fault point direction determination are The information is output to the failure information display unit 90 and stored. When the failure level K obtained from the voltage sensor series peak level detector 51b is smaller than the set level, the detected voltage waveform data of the voltage sensor series before the arithmetic processing at the time of failure is replaced with the failure phase output F. The output A of the phase measuring device 54 may be used.
[0058]
When the transmission line is determined to be faulty and the line is cut off, the cutoff detection unit 80 pays attention to the fact that the fault current disappears and the transmission voltage drops after a certain period of time, and a ground fault occurs after a certain time from the occurrence of the fault. The failure level J obtained from the sensor-system peak level detector 51a (which can be substituted by the failure level L obtained from the short-circuit sensor peak-level detector 51c) is smaller than that at the time of occurrence of the failure, and the voltage sensor series arithmetic processing Based on the logical product of the previous detected voltage waveform data (the output M of the pre-calculation peak level detector 53) being lower than normal, a cutoff detection signal for the transmission line is output. The switches SE1 and SE2 interposed between the output lines L1 and L2 for supplying the direction determination result to the respective indicators 92 and 94 are closed by the cutoff detection signal, and the one end or the other end indicators 92 and 94 are closed. Is displayed on any one of them based on the result of the above-described failure point direction determination.
[0059]
As shown in FIG. 14, the failure information display unit 90 includes a clock 96 therein, and measures and stores the time at which the failure has occurred. At that time, the failure type determination unit 60 and the failure point direction determination unit 70 The various phases, level data, judgment results, and the like used in step (1) are also stored and can be displayed as needed. In the event that a failure occurs multiple times in a short period of time, these data are compared with the failure occurrence time recorded at the electric substation to confirm the temporal consistency of similar devices installed at multiple locations. However, it can be used as information for comprehensive failure point determination and failure cause analysis. Further, in this case, time correction means 98 is provided which utilizes the fact that the detected voltages of the voltage sensors 2u and 2d are at the commercial frequency, and synchronously corrects the internal clock 96 for each scheduled time with the detected waveform (for example, a zero-cross point). By doing so, the time lag of the clock 96 can be substantially eliminated.
[0060]
FIG. 16 is a schematic diagram showing a main part of a third embodiment in which the present invention is applied to a transmission line in which two parallel lines are arranged in opposite phases. Except that the upper and lower short-circuit sensors 4u, 4d are installed on the line connecting the uppermost and lowermost transmission lines, respectively, and the voltage sensor 2 is installed on the line connecting the middle transmission line pair, It is the same as FIG. 11, and the same reference numerals as those in FIG. 11 represent the same parts. The rod-shaped cores of the short-circuit sensors 4u and 4d are installed so as to be substantially perpendicular to the ground. FIG. 17 shows a state of a short-circuit current flowing in each transmission line when an A1-B1 phase short-circuit fault occurs at the point X in the single-ended power supply system of the reverse-phase arrangement of FIG. IS1 is a short-circuit current flowing from the power supply terminal SS1 to the fault point X directly through the lower fault lines A1 and B1, and IS2 is a short-circuit current flowing from the upper healthy lines A2 and B2 to the fault point X through the substation SS2. It is a current. Since the upper short-circuit sensor 4u is close to the power line A1, it generates an output voltage VSU proportional to the short-circuit current flowing through the power line A1 as a failure component. On the other hand, since the lower short-circuit sensor 4d is close to the power line A2, it detects an output voltage VSL proportional to the short-circuit current flowing therethrough as a fault component. Since the erection order (phase) of the power lines viewed from each of the short-circuit sensors 4u and 4d is opposite on the right and left sides of the short-circuit sensor, at the point P1 on the power supply side from the fault point X, the upper short-circuit sensor 4u The obtained fault component voltage VSU and the fault component voltage VSL obtained from the lower short-circuit sensor 4u are opposite to each other, while the fault component voltage VSU obtained from the upper and lower short-circuit sensors 4u and 4d at the point P2 on the load side of the fault point X. The fault component voltages VSU and VSL are in the same direction.
[0061]
Therefore, when the present invention is applied to such a negative-phase-sequence transmission line, the fault point direction determination unit 70 compares the phases of the fault component voltages obtained from the upper and lower short-circuit sensors 2u and 2d, According to this, it is possible to determine the direction of the fault point viewed from the position of the short-circuit sensor installation. Since the short-circuit currents have a relationship of IS1> IS2, the phase of the composite voltage of the fault component voltages of the upper and lower short-circuit sensors 2u and 2d is A1 at point P1, and A1 is also at point P2. Is obtained. Therefore, when the phase of the composite value of the fault component of the upper and lower short-circuit sensors is compared with the voltage waveform of the voltage sensor or the phase of the fault component as the phase of the short-circuit current, the short-circuit sensor is determined in the same manner as described above according to whether the phase is the same or the opposite. The direction of the failure point viewed from the installation position can also be determined.
[0062]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the installation position and sensitivity adjustment at the time of attaching at least one of a ground fault sensor, a short circuit sensor, and a voltage sensor to the pylon of the arbitrary places of a power transmission line are simplified (it becomes unnecessary in some cases). The required time, labor, and skill level can be reduced, and the zero-sequence voltage and the fault component of the sensor output can be easily obtained by the arithmetic processing. Therefore, the margin for designing various sensors is increased, and the cost is easily reduced. It is. In addition, since the phase voltage can be detected by the voltage sensor even at the time of a short-circuit failure, the failure type or the failure phase can be easily determined by comparing the waveform and the level before and after the arithmetic processing of the voltage sensor. Furthermore, if an indicator is attached to the tower equipped with these sensors in addition to the fault / direction judging device, the direction of the fault point that occurred on the transmission line can be determined on the power line at both ends and the power line at one end by itself. It is possible to determine and display. Also, if a memory that stores the failure occurrence time, the level and phase of the failure component of each sensor output, the failure type, the direction of the failure point, etc. is prepared, if the failure occurs continuously in a short time In addition, accident classification and failure analysis can be performed.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an example of arrangement of voltage sensors in a first embodiment in which the present invention is applied to a standard transmission line tower having two parallel lines and an in-phase arrangement.
2A and 2B are voltage vector diagrams showing an output of an upper voltage sensor in FIG. 1, wherein FIG. 2A shows a normal state and FIG. 2B shows a phase A ground fault.
3A and 3B are voltage vector diagrams showing an output of a lower voltage sensor in FIG. 1, wherein FIG. 3A shows a normal state, and FIG. 3B shows a phase A ground fault.
FIGS. 4A and 4B are voltage vector diagrams at the time of an A and B phase ground fault in FIG. 1, wherein FIG. 4A shows an output of an upper voltage sensor and FIG. 4B shows an output of a lower voltage sensor.
5A and 5B are voltage vector diagrams when the AB phase is short-circuited in FIG. 1, wherein FIG. 5A shows an output of an upper voltage sensor and FIG. 5B shows an output of a lower voltage sensor.
FIG. 6 is a schematic side view showing an example of the arrangement of voltage sensors in another embodiment in which the present invention is applied to a horizontally arranged power transmission tower.
FIG. 7 is a schematic side view showing an arrangement example of a voltage sensor in still another embodiment in which the present invention is applied to a vertically arranged power transmission tower.
FIG. 8 is a schematic side view showing an example of arrangement of voltage sensors in another embodiment in which the present invention is applied to a triangular array power transmission tower.
FIG. 9 is a schematic side view showing an example of the arrangement of voltage sensors in still another embodiment in which the present invention is applied to a four-circuit power transmission tower.
FIG. 10 is a block diagram of a first embodiment of the present invention.
FIG. 11 is a schematic side view showing an example of arrangement of various sensors in a second embodiment in which the present invention is applied to a standard transmission line tower having two parallel lines and an in-phase arrangement.
FIG. 12 is a block diagram showing a hardware configuration of the second embodiment together with FIGS.
FIG. 13 is a block diagram showing a hardware configuration of the second embodiment together with FIGS.
FIG. 14 is a block diagram showing a hardware configuration of the second embodiment together with FIGS.
FIG. 15 is a conceptual diagram for explaining a fault point direction determining operation according to the second embodiment.
FIG. 16 is a schematic side view showing an example of arrangement of various sensors in a third embodiment in which the present invention is applied to a transmission line tower having a parallel two-circuit reverse-phase arrangement.
FIG. 17 is a conceptual diagram showing a state of a short-circuit current when a phase short-circuit accident has occurred in the transmission line shown in FIG. 16;
FIG. 18 is a schematic diagram for explaining a problem when a ground fault occurs in a transmission line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transmission tower 2u, d ... Upper and lower voltage sensor 3u, d ... Upper and lower ground fault sensor 4 ... Short circuit sensor 4u, d ... Upper and lower short circuit sensor 5 ... Fault / direction discriminator 6 ... Display 30 ... Waveform Data operation units 31a-c delay circuits 32a-c subtraction circuits 33a addition circuits 40 waveform data storage units 41a-c fault component memories 42a-c normal waveform memories 44a-c fault occurrence detectors 43a-c 63, setting value 50, level / phase measuring unit 51a-c, peak level detector 52a-c, phase measuring device 60, fault type determining unit 70, fault point determining unit 71, 72, phase comparator 80, interruption detection Unit 90: Failure information display unit 92, 94 ... Indicator 96 ... Clock 98 ... Time correction means VA, VB, VC ... Phase voltage vector Vo ... Zero-phase voltage vector VU, VL ... Upper and lower Output voltage vector VUo, VLo, VUS, VLS... Subtracted voltage vector of normal voltage sensor

Claims (4)

One line is arranged on each of the left and right sides, and these are arranged on the lines that connect the upper and lower power lines of the transmission line , which are in opposite phases to each other , respectively, and each of the pair detects a fault current component flowing when a fault occurs in the transmission line. A short circuit sensor,
A transmission line that compares a phase of a fault current component detected by the pair of short-circuit sensors and generates a signal indicating a direction of a short-circuit fault point viewed from an installation position of the short-circuit sensor based on the comparison result. Failure monitoring device. One line is arranged on each of the left and right sides, and these are arranged on the lines that connect the upper and lower power lines of the transmission line , which are in opposite phases to each other , respectively, and each of the pair detects a fault current component flowing when a fault occurs in the transmission line. A short circuit sensor,
In the power transmission tower, a voltage sensor equipped to generate an output even when the transmission line is normal,
Means for calculating the phase of the composite current of the fault current component based on the phase of the output of the voltage sensor ,
A comparator that compares a phase of the combined current and a phase of an output of the voltage sensor when an accident occurs, and generates a signal indicating a direction of a short-circuit fault point viewed from an installation position of the short-circuit sensor based on the comparison result. A transmission line fault monitoring device, characterized in that: Further, a calculation means for calculating a difference between the output of the voltage sensor at the time of occurrence of an accident and the output at the time of normality to obtain a subtracted voltage vector,
The comparator may compare a phase of the subtraction voltage vector with a phase of a combined current, and generate a signal indicating a direction of a short-circuit fault point viewed from an installation position of the short-circuit sensor based on the comparison result. Item 3. A transmission line failure monitoring device according to item 2. The transmission line fault monitoring device according to any one of claims 1 to 3, wherein each short-circuit sensor is configured by winding a coil around a rod-shaped core, and the rod-shaped core is installed substantially perpendicular to the ground.

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