JP4127655B2

JP4127655B2 - Lightning damage protection method for single-phase distribution lines

Info

Publication number: JP4127655B2
Application number: JP2003052785A
Authority: JP
Inventors: 仁志杉本; 由伸浅岡; 一夫中田
Original assignee: Hokuriku Electric Power Co
Current assignee: Hokuriku Electric Power Co
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2008-07-30
Anticipated expiration: 2023-02-28
Also published as: JP2004266900A

Description

【０００１】
【発明の属する技術分野】
本発明は、単相配電線路において避雷装置を一相省略しての雷被害防護方法に関するものである。
【０００２】
【従来の技術】
今日、配電線路における雷被害の多くは、直撃雷や誘導雷により発生する雷過電圧により高圧がいし等の絶縁が破壊されることに因り発生しており、こういった雷被害への対策として、避雷装置（雷過電圧を抑制して絶縁破壊を回避するJEC-203-1978「避雷器」やJEC-217-1984「酸化亜鉛形避雷器」に準拠した避雷器、及び雷過電圧の抑制を目的とした機材で酸化亜鉛素子に代表される避雷素子を用いたもの）を取り付ける方法が従来から採られている。
【０００３】
また、前記線路の雷被害のうち、雷過電圧の絶縁破壊が二相以上で起こることによって異相地絡短絡となり、商用周波の続流により高圧電線の断線等の被害を被る場合がある。一般的に、雷による絶縁破壊を完全に防止するには、全ての電柱の全ての相に前記避雷装置を取り付ける必要がある（例えば、単相配電線路では二つの相全てに避雷装置を取り付ける）が、特に単相配電線路においては、当該単相を構成する片側の一相に避雷装置を取り付けてるのみであっても異相地絡短絡を防止することが出来る場合がある。
【０００４】
【発明が解決しようする課題】
しかしながら、三相配電線路であっても、前記単相配電線路の考え方に基づき、定められた二相に避雷装置が取り付けてあれば異相地絡短絡の防止が可能であるとして避雷装置の取り付けが一相省略されている場合がある。その様に、三相配電線路のうちの一相について前記避雷装置の取り付けを省略した場合にあっては、単相配電線路は、専ら三相配電線路からの分岐点を始点として引き出されたものであるため、例えば、三相配電線路のうちで避雷装置を省略していない二相から単相配電線路を引き出して、そのうちの一相の避雷装置を省略すると、三相配電線路の避雷装置を省略した相と、引き出された単相配電線路の避雷装置を省略した相との絶縁破壊が同時に生じることによって異なる柱を介しての異相地絡短絡となり、商用周波の続流による被害を被る可能性があった。
【０００５】
本発明は、上記実情に鑑みて為されたものであって、低い雷短絡被害率を維持しつつ、避雷装置の取り付けを省略し得る単相配電線路の雷被害防護方法の提供を目的とする。
【課題を解決するための手段】
【０００６】
上記課題を解決する為に為された本発明による単相配電線路の雷被害防護方法は、全ての電柱について避雷装置が全相取り付けられた三相配電線路から二相を引き出してなる単相配電線路の、全ての電柱について定められた一相のみの避雷装置の取り付けを省略することを特徴とする。
【０００７】
また、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路から、前記避雷装置の取り付けが省略された相を含む二相を引き出してなる単相配電線路については、当該単相配電線路の全ての電柱について前記避雷装置の取り付けが省略された相から延長された相の避雷装置のみを省略する単相配電線路の雷被害防護方法を採っても良い。
【０００８】
更に、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路から、前記避雷装置の取り付けが省略された相を除く二相を引き出してなる単相配電線路については、当該単相配電線路の始点から数えて少なくとも一つ目の電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けると共に、前記単相配電線路における全相に避雷装置を取り付けた電柱以降の電柱について定められた一相のみの前記避雷装置の取り付けを省略する単相配電線路の雷被害防護方法を採っても良い。
【０００９】
【発明の実施の形態】
以下、本発明による単相配電線路の雷被害防護方法の実施の形態と共に図面に基づき説明する。
図１は、全ての電柱について避雷装置が全相取り付けられた三相配電線路から二相を引き出してなる単相配電線路であって、全ての電柱について定められた一相のみの避雷装置の取り付けを省略した単相配電線路の例である。
【００１０】
図１（イ）は、本発明による雷被害防護方法の第一の実施の形態であり。三相全てに避雷装置を取り付けた三相配電線路の末端柱から単相配電線路を延長をする例を示した単相配電線路であり、図１（ロ）は、本発明による雷被害防護方法の第二の実施の形態であり、三相全てに避雷装置を取り付けた三相配電線路の途中から単相配電線路を分岐延長する例を示した単相配電線路である。これらの例にあっては、前記三相配電線路の三相全てに避雷装置を取り付けたことにより、当該三相配電線路と、単相配電線路における避雷装置の取り付けを省略した相（以下、避雷装置省略相と記す。）とで絶縁破壊が同時に発生することが防止されているので、短絡の雷被害が回避される。
【００１１】
図２は、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路から、前記避雷装置省略相を含む二相を引き出してなる単相配電線路の、全ての電柱について前記避雷装置省略相から延長された相の避雷装置のみを省略した単相配電線路の例である。
【００１２】
図２（イ）は、本発明による雷被害防護方法の第三の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の末端柱から単相配電線路を延長をする例を示した単相配電線路である。また、図２（ロ）は、本発明による雷被害防護方法の第四の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の途中から単相配電線路を分岐延長する例を示した単相配電線路である。
【００１３】
更に、図３（イ）は、本発明による雷被害防護方法の第五の実施の形態であり、前記三相配電線路において前記単相配電線路の引き出し点となる末端柱の全ての相に前記避雷装置を取り付けると共に、当該末端柱から単相配電線路を延長をする例を示した単相配電線路である。また、図３（ロ）は、本発明による雷被害防護方法の第六の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の途中から分岐延長した単相配電線路であって、前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付ける例を示した単相配電線路である。今日では、実務上、前記三相配電線路において前記単相配電線路の引き出し点となる末端柱の全ての相に前記避雷装置を取り付けるのが一般的である。
【００１４】
これらの例にあっては、前記三相配電線路における避雷装置省略相を含む二相を引き出して単相配電線路を構成したことにより、当該三相配電線路の避雷装置省略相から延長された単相配電線路の避雷装置省略相と、もう一方の避雷装置を取り付けた相とで絶縁破壊が同時に発生することが防止されているので、短絡の雷被害が回避される。
【００１５】
図４は、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路から、前記避雷装置の取り付けが省略された相を除く二相を引き出してなる単相配電線路の、始点から数えて少なくとも一つ目の電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けると共に、前記単相配電線路における全相に避雷装置を取り付けた電柱以降の電柱について定められた一相のみの前記避雷装置の取り付けを省略する単相配電線路の例を示したものである。
【００１６】
図４（イ）は、本発明による雷被害防護方法の第七の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の末端柱から単相配電線路を延長すると共に、当該単相配電線路の始点から一つ目の電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けた単相配電線路の例を示したものである。また、図４（ロ）は、本発明による雷被害防護方法の第八の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の末端柱から単相配電線路を延長すると共に、当該単相配電線路の始点から二つ目までの電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けた単相配電線路の例を示したものである。
【００１７】
更に、図５（イ）は、本発明による雷被害防護方法の第九の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の途中から分岐延長した単相配電線路であって、当該単相配電線路の始点から一つ目の電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けた単相配電線路の例を示したものである。また、図５（ロ）は、本発明による雷被害防護方法の第十の実施の形態であり、全ての電柱について定められた一相のみの避雷装置の取り付けが省略された三相配電線路の途中から分岐延長した単相配電線路であって、当該単相配電線路の始点から二つ目までの電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けた単相配電線路の例を示したものである。
【００１８】
これらの例にあっては、前記三相配電線路における避雷装置省略相を除く二相を引き出して単相配電線路を構成してあるが、前記単相配電線路の始点から数えて少なくとも一つ目の電柱における全ての相、及び前記三相配電線路において前記単相配電線路の引き出し点となる電柱の全ての相に前記避雷装置を取り付けることで、たとえ、前記三相配電線路及び単相配電線路に架空地線や通信線用吊架線が架設されていてもそれらを通じて短絡する被害率が低減される。
【００１９】
以下、前記第七の実施の形態乃至第十について、異柱間における地絡短絡について実験を行うと共に、ＥＭＴＰ解析を用いてこの様な線路形態による単相配電線路の雷被害防護方法の効果について検討する。
【００２０】
異柱間の地絡短絡とは、三相配電線路の避雷装置省略相と単相配電線路の避雷装置省略相とにおいて絶縁破壊が同時に発生し、架空地線や通信線用吊架線を通じて短絡することである。ここでの実験では、雷により異柱の異相で絶縁破壊が発生する回路を模擬し、隣接柱間での異相地絡短絡が継続して被害（ここでは高圧電線５ｍｍの断線）に至る可能性を検討した。
【００２１】
その結果、架空地線が施設された配電線路で異柱間での異相地絡が発生した場合、３００Ａ程度の短絡電流で短絡が継続し被害が発生する可能性があることが確認できた。一方、架空地線がない配電線路では、大地を経由した異柱間での異相地絡短絡は発生しないが、通信線用吊架線が存在するとそれが経路となって短絡が継続し被害に至る可能性があることが確認できた。即ち、配電線の支持物である電柱の大部分には、電話回線や通信線、CATV用ケーブルなど様々な通信線類が併架されており、これらが架空地線の無い配電線でも通信線用吊架線が容易に異柱間の地絡短絡の経路と成り得ることが実験によって確認されたと言える。
【００２２】
解析による検討ではこの実験結果を考慮して、「架空地線がある場合」と「架空地線が無く、通信線用吊架線がある場合」の2つの解析回路を対象とし、雷被害防護の効果を定量的に比較するために、雷短絡被害率により比較検討した。尚、雷短絡被害率は、1回の配電線直撃雷により異柱間の地絡短絡が発生する確率である。
【００２３】
以下、解析条件を説明する。
三相共に避雷装置が取り付けられた三相末端柱から単相延長をする場合の解析環境は以下の通りである。三相配電線路は支持物（コンクリート柱）と三相の高圧線で構成され、条件に応じて一線の架空地線もしくは一線の通信線用吊架線が追加される。単相配電線は、三相配電線路と同様であるが高圧線からなる二相である。
【００２４】
配電線路の両端は、多導体系線路のサージインピーダンスに相当する整合抵抗で終端した。通常、三相配電線路の末端柱には避雷装置が三相ともに取り付けられており、また現在、日本の電力会社では約4径間置き（支持物5本のうち1本）に三相一組の避雷器が取り付けられている実績があることから、その様な実情に沿って三相配電線路の末端柱には避雷器が三相共に取り付けられることとし、当該末端柱を基準に4径間置き（160ｍ）に配電線路全相に避雷器が取り付けられ接地（30Ωの接地抵抗Ｒａ）する解析回路を設定した（図６及び図７参照）。
【００２５】
その他の支持物には避雷装置をそれぞれ一相を省いて取り付けるようにし、異柱間の地絡短絡が発生するよう三相配電線路と単相配電線路では避雷装置を省く相は異なるようにした。避雷装置の接地としては、雷に対して支持物の埋設部分が接地極となることを考慮し、この支持物の接地抵抗Ｒｂ（150Ω）に接続した。架空地線や通信線用吊架線の接地は、避雷器がある支持物では避雷器の接地抵抗Ｒａに、避雷装置のある支持物は、支持物の埋設部分の接地抵抗Ｒｂに、それぞれ接続した。雷撃箇所は、架空地線がある配電線路では三相配電線路の末端柱の架空地線に、架空地線が無い配電線路では三相配電線路の末端柱の支持物頂部とした（表１参照）。
【００２６】
【表１】

【００２７】
一方、二相の避雷装置がある三相配電線路の途中から単相配電線路を分岐延長する場合の解析環境は、ほぼ三相の避雷装置がある三相末端柱から単相延長をする場合と同様であるが、配電線路には3ヶ所の終端部それぞれについて多導体系線路のサージインピーダンスに相当する整合抵抗で終端した（図８参照）。雷撃箇所は、三相配電線路から単相配電線路が分岐する三相配電線路の支持物頂部とした。
【００２８】
線路の抵抗やインダクタンスなどの定数は、ＥＭＴＰのＪＭＡＲＴＩセットアップサブプログラムを用いて算出した。配電線路に直撃する雷撃電流波形は、図９に示す波尾長70μ秒の三角波形とし、配電線路に発生する雷過電圧に影響を与える雷撃電流波頭長および雷撃電流波高値をパラメータ（解析に用いた雷撃電流の波形パラメータを以下の表２に示す。）として変化させ、雷短絡被害率を下記の如く算出することとした。尚、異柱間の地絡短絡の発生については、三相配電線路の避雷装置省略相と単相配電線路の避雷装置省略相で絶縁破壊が同時に発生した場合に短絡が発生すると仮定した。（自然消弧の可能性は考慮していない。）
【００２９】
【表２】

【００３０】
雷短絡被害率の計算方法は以下の通りである。先ず、解析回路ごとに雷撃電流の各波頭長に対して異柱間の地絡短絡が発生する最小の雷撃電流波高値を求め、雷短絡被害が発生する雷撃電流波頭長と雷撃電流波高値の関係を求める（図１０参照）。そして、図１０の関係曲線において、雷短絡被害が生じる閾値を超える側の範囲（図１０の斜線部）について、雷撃電流の波頭長Tfおよび波高値Ipのそれぞれの確率を表２に基づいて求め、積分すれば、雷短絡被害率Pfを求めることができる（数１参照）。尚、ここでは、雷撃電流波頭長の対数値の確率密度関数および雷撃電流波高値の対数値の確率密度関数が正規分布に従い、それぞれ独立であるとして算出する。
【００３１】
【数１】

【００３２】
上記環境及び条件に基づき解析した結果、図１１の如く単相配電線路における全て電柱について一定の相の避雷装置を省略すると、架空地線の無い線路の雷短絡被害率は7.5%、架空地線がある線路のそれは2.6%となり、単相配電線路の最初の支持物と2番目の支持物で全相に避雷装置を取り付けると、架空地線の有無に関わらず雷短絡被害率は0.1%までに低減できることがわかる。
【００３３】
また、図１２の架空地線の無い線路では、単相配電線路全ての1つの相の避雷装置を省略する場合の雷短絡被害率は14.4%となり、単相配電線路が接続される三相の支持物、単相配電線路の最初の支持物および単相配電線路の2番目の支持物の3ヶ所で全相に避雷装置を取り付けると、雷短絡被害率は1.0%までに低減できることがわかる。
【００３４】
尚、二相に避雷装置がある三相配電線路の途中から単相線路を分岐延長する場合の解析では、三相の避雷装置がある三相末端柱から単相延長をする場合の解析結果より、架空地線が無く、通信線用吊架線がある条件の方、雷短絡被害率が大きいという結果が得られたので、被害が起きやすい架空地線が無く、通信線用吊架線がある条件のみを検討することとした。
【００３５】
【発明の効果】
以上の如く本発明による単相配電線路の雷被害防護方法によれば、三相配電線路において避雷装置の取り付けが一相省略されている場合であっても、当該三相配電線路から引き出された単相配電線路について、そのうちの一相の避雷装置を省略した際に、三相配電線路の避雷装置を省略した相と、引き出された単相配電線路の避雷装置を省略した相とで絶縁破壊が生じることによって異なる柱を介しての異相地絡短絡となる可能性を効果的に低減でき、低い雷短絡被害率を維持しつつ、避雷装置の取り付けを省略し得る低コストな単相配電線路の提供に寄与することとなる。
【図面の簡単な説明】
【図１】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の第一の実施の形態及び第二の実施の形態を示すモデル図である。
【図２】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の第三の実施の形態及び第四の実施の形態を示すモデル図である。
【図３】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の第五の実施の形態及び第六の実施の形態を示すモデル図である。
【図４】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の第七の実施の形態及び第八の実施の形態を示すモデル図である。
【図５】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の第九の実施の形態及び第十の実施の形態を示すモデル図である。
【図６】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の解析回路の一例を示すモデル図及び等価回路図である。
【図７】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の解析回路の一例を示すモデル図及び等価回路図である。
【図８】（イ）（ロ）本発明による単相配電線路の雷被害防護方法の解析回路の一例を示すモデル図及び等価回路図である。
【図９】本発明による単相配電線路の雷被害防護方法の解析に用いた配電線路に直撃する雷撃電流波形の一例を示したグラフである。
【図１０】解析回路における雷撃電流の波頭長と雷撃電流の波高値との関係の一例を示したグラフである。
【図１１】三相の避雷装置がある三相末端柱から単相延長をする場合の対策方法別の雷短絡被害率を示したグラフである。
【図１２】二相の避雷装置がある三相配電線路の途中から単相配電線路を分岐延長する場合の対策方法別の雷短絡被害率を示したグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning damage protection method in which a single lightning arrester is omitted in a single-phase distribution line.
[0002]
[Prior art]
Today, most of lightning damage in distribution lines is caused by the breakdown of insulation such as high voltage insulators caused by lightning overvoltage caused by direct lightning or induced lightning. Equipment (Lightning arresters conforming to JEC-203-1978 “Lightning Arrestor” and JEC-217-1984 “Zinc Oxide Lightning Arrester”, which suppresses lightning overvoltage and avoids dielectric breakdown, and equipment with the purpose of suppressing lightning overvoltage) A method of attaching a lightning protection element represented by a zinc element) has been conventionally employed.
[0003]
In addition, among the lightning damages of the line, there may be a case where a dielectric breakdown of lightning overvoltage occurs in two or more phases, resulting in an out-of-phase ground short circuit, and damage such as disconnection of a high-voltage electric wire due to a commercial frequency continuity. In general, in order to completely prevent breakdown due to lightning, it is necessary to install the lightning arrester on all phases of all power poles (for example, in a single-phase distribution line, lightning arresters are installed on all two phases). However, in particular, in a single-phase distribution line, even if a lightning protection device is only attached to one phase on one side constituting the single phase, a different-phase ground fault short circuit may be prevented.
[0004]
[Problems to be solved by the invention]
However, even if it is a three-phase distribution line, based on the concept of the single-phase distribution line, if a lightning arrester is attached to the two specified phases, it is possible to prevent a short-circuit ground fault short-circuit, One phase may be omitted. As such, when the installation of the lightning arrester is omitted for one phase of the three-phase distribution line, the single-phase distribution line is drawn exclusively from the branch point from the three-phase distribution line. Therefore, for example, if a single-phase distribution line is pulled out from the two phases of the three-phase distribution line where the lightning protection device is not omitted, and if one of the lightning protection devices is omitted, the lightning protection device of the three-phase distribution line is Simultaneous insulation breakdown between the omitted phase and the phase without the lightning arrester on the single-phase distribution line leads to a short-circuit ground fault across different columns, which can be damaged by the commercial frequency continuity. There was sex.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a lightning damage protection method for a single-phase distribution line capable of omitting the installation of a lightning arrester while maintaining a low lightning short-circuit damage rate. .
[Means for Solving the Problems]
[0006]
The lightning damage protection method for a single-phase distribution line according to the present invention made to solve the above problems is a single-phase distribution line in which two phases are drawn out from a three-phase distribution line in which all phases of lightning arresters are attached to all utility poles. It is characterized by omitting the installation of the lightning arrester of only one phase determined for all the power poles of the road.
[0007]
In addition, a single-phase distribution line formed by drawing out two phases including a phase in which the installation of the lightning arrester is omitted from a three-phase distribution line in which the installation of the lightning arrester of only one phase is omitted for all utility poles May adopt a lightning damage protection method for a single-phase distribution line that omits only the lightning arrester of the phase extended from the phase in which the installation of the lightning arrester is omitted for all the utility poles of the single-phase distribution line.
[0008]
Further, a single-phase distribution line formed by drawing out two phases excluding a phase where the installation of the lightning arrester is omitted from a three-phase distribution line where the installation of the lightning protection device of only one phase determined for all utility poles is omitted. The lightning arrester is applied to all phases of at least the first utility pole counted from the starting point of the single-phase distribution line, and to all phases of the utility pole that is the extraction point of the single-phase distribution line in the three-phase distribution line. Even if the lightning damage protection method for the single-phase distribution line is omitted, the installation of the lightning arrester for only one phase, which is defined for the power pole after the power pole with the lightning protection device attached to all phases in the single-phase distribution line, is omitted. good.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, a lightning damage protection method for a single-phase distribution line according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 shows a single-phase distribution line that draws two phases from a three-phase distribution line with all phases of lightning arresters attached to all utility poles. It is an example of the single phase distribution line which omitted o.
[0010]
FIG. 1 (a) is a first embodiment of a lightning damage protection method according to the present invention. This is a single-phase distribution line that shows an example of extending a single-phase distribution line from the end pole of a three-phase distribution line with all three phases equipped with lightning arresters. FIG. 1 (b) shows a lightning damage protection method according to the present invention. This is a single-phase distribution line showing an example of branching and extending a single-phase distribution line from the middle of a three-phase distribution line with lightning arresters attached to all three phases. In these examples, by installing a lightning arrester on all three phases of the three-phase distribution line, the three-phase distribution line and a phase in which the lightning arrester is not installed in the single-phase distribution line (hereinafter referred to as lightning protection) In this case, it is possible to prevent lightning damage due to short circuit.
[0011]
FIG. 2 shows all of the single-phase distribution lines formed by drawing out two phases including the lightning arrester omitted phase from the three-phase distribution line omitting the installation of the lightning arrester of only one phase defined for all utility poles. It is an example of the single-phase distribution line which abbreviate | omitted only the lightning arrester of the phase extended from the said lightning arrester omission phase about the utility pole.
[0012]
FIG. 2 (a) is a third embodiment of the lightning damage protection method according to the present invention, and is a terminal pole of a three-phase distribution line in which the installation of a lightning arrester of only one phase defined for all utility poles is omitted. It is the single phase distribution line which showed the example which extends a single phase distribution line from. FIG. 2 (b) is a fourth embodiment of the lightning damage protection method according to the present invention, and shows a three-phase distribution line in which the installation of a lightning arrester of only one phase defined for all utility poles is omitted. It is the single phase distribution line which showed the example which branches and extends a single phase distribution line from the middle.
[0013]
Further, FIG. 3 (a) shows a fifth embodiment of the lightning damage protection method according to the present invention, wherein the three-phase distribution line has all the phases of the end pillars serving as the extraction points of the single-phase distribution line. It is the single phase distribution line which showed the example which extends a single phase distribution line from the said end pillar while attaching a lightning arrester. FIG. 3 (b) is a sixth embodiment of the lightning damage protection method according to the present invention, and shows a three-phase distribution line in which the installation of a lightning arrester of only one phase defined for all utility poles is omitted. It is a single-phase distribution line that is branched and extended from the middle, and is a single-phase distribution line that shows an example in which the lightning arrester is attached to all phases of a utility pole that is a pull-out point of the single-phase distribution line in the three-phase distribution line . Nowadays, in practice, it is common to attach the lightning arrester to all phases of the terminal column that is the pull-out point of the single-phase distribution line in the three-phase distribution line.
[0014]
In these examples, a single-phase distribution line is constructed by drawing out two phases including the lightning arrester omitted phase in the three-phase distribution line, so that the single-phase extended from the lightning arrester omitted phase in the three-phase distribution line is provided. Since breakdown of the lightning arrester omitted phase in the phase distribution line and the phase where the other lightning arrester is attached are prevented from occurring simultaneously, lightning damage due to short circuit is avoided.
[0015]
FIG. 4 shows a single-phase distribution line in which two phases other than the phase where the installation of the lightning arrester is omitted are drawn from the three-phase distribution line where the installation of the lightning protection device of only one phase determined for all utility poles is omitted. The lightning arrester is attached to all phases of at least the first utility pole counted from the starting point of the road, and to all phases of the utility pole to be drawn out of the single-phase distribution line in the three-phase distribution line. The example of the single phase distribution line which abbreviate | omits the installation of the said lightning arrester of only one phase defined about the utility pole after the utility pole which attached the lightning arrester to all the phases in a phase distribution line is shown.
[0016]
FIG. 4 (a) is a seventh embodiment of the lightning damage protection method according to the present invention, and the terminal pole of the three-phase distribution line where the installation of the lightning arrester of only one phase defined for all the power poles is omitted. From the starting point of the single-phase distribution line, all phases in the first utility pole, and all phases of the utility pole that are the extraction points of the single-phase distribution line in the three-phase distribution line The example of the single phase distribution line which attached the said lightning arrester to is shown. FIG. 4 (b) is an eighth embodiment of the lightning damage protection method according to the present invention, and shows a three-phase distribution line where the installation of a lightning arrester of only one phase defined for all utility poles is omitted. Extending the single-phase distribution line from the terminal pole, all the phases in the power pole from the start point of the single-phase distribution line to the second, and the poles serving as the extraction points of the single-phase distribution line in the three-phase distribution line The example of the single phase distribution line which attached the said lightning arrester to all the phases is shown.
[0017]
Further, FIG. 5 (a) shows a ninth embodiment of the lightning damage protection method according to the present invention, in which a three-phase distribution line in which the installation of a lightning arrester of only one phase defined for all utility poles is omitted. A single-phase distribution line that is branched and extended from the middle, including all phases in the first utility pole from the starting point of the single-phase distribution line, and a utility pole that becomes a pull-out point of the single-phase distribution line in the three-phase distribution line The example of the single phase distribution line which attached the said lightning arrester to all the phases is shown. FIG. 5 (b) is a tenth embodiment of the lightning damage protection method according to the present invention, and shows a three-phase distribution line in which the installation of a lightning arrester of only one phase defined for all utility poles is omitted. A single-phase distribution line branched and extended from the middle, all the phases in the utility pole from the start point to the second of the single-phase distribution line, and the utility pole that becomes the pull-out point of the single-phase distribution line in the three-phase distribution line The example of the single phase distribution line which attached the said lightning arrester to all the phases of is shown.
[0018]
In these examples, a single-phase distribution line is constructed by pulling out two phases excluding the lightning protection device omitted phase in the three-phase distribution line, but at least the first phase counted from the starting point of the single-phase distribution line. By attaching the lightning arrester to all phases of the utility poles and to all phases of the utility poles that are the extraction points of the single-phase distribution lines in the three-phase distribution lines, the three-phase distribution lines and the single-phase distribution lines Even if an overhead ground wire or a suspension wire for a communication line is installed in the cable, the rate of damage caused by short circuiting through them is reduced.
[0019]
Hereinafter, with respect to the seventh embodiment to the tenth, while conducting an experiment on a ground fault short circuit between different columns, the effect of the lightning damage protection method for a single-phase distribution line by such a line configuration using EMTP analysis consider.
[0020]
Ground fault short-circuit between different pillars means that insulation breakdown occurs simultaneously in the lightning arrester omitted phase of the three-phase distribution line and the lightning arrester omitted phase of the single-phase distribution line, and short-circuits through the overhead ground wire and the suspension line for communication lines. That is. In this experiment, a circuit in which dielectric breakdown occurs in different phases of different pillars due to lightning may cause damage (here, disconnection of 5mm high-voltage wire) due to continuous short-circuit ground faults between adjacent pillars. It was investigated.
[0021]
As a result, it was confirmed that when a different-phase ground fault occurs between different pillars on the distribution line where the overhead ground line is installed, there is a possibility that the short-circuit continues with a short-circuit current of about 300 A and damage may occur. On the other hand, in a distribution line with no overhead ground wire, no out-of-phase short-circuit occurs between different pillars via the ground, but if there is a suspension line for communication lines, it becomes a route and the short-circuit continues and damage occurs It was confirmed that there was a possibility. In other words, most of the utility poles that support the distribution lines are equipped with various types of communication lines such as telephone lines, communication lines, and cable for CATV. It can be said that it was confirmed by experiments that the suspension line for use could easily be a path for short circuit between different pillars.
[0022]
Considering the results of this experiment, the analysis study targets two analysis circuits, `` when there is an overhead ground wire '' and `` when there is no overhead ground wire and there is a suspension wire for communication lines ''. In order to compare the effects quantitatively, a comparison was made based on the lightning short-circuit damage rate. The lightning short-circuit damage rate is the probability that a ground fault short-circuit between different columns will occur due to a single lightning strike on a distribution line.
[0023]
The analysis conditions will be described below.
The analysis environment for single-phase extension from a three-phase end column with lightning arresters attached to the three phases is as follows. A three-phase distribution line is composed of a support (concrete column) and a three-phase high-voltage line, and a single overhead ground line or a single communication line suspension line is added depending on conditions. Single-phase distribution lines are similar to three-phase distribution lines but are two-phase consisting of high-voltage lines.
[0024]
Both ends of the distribution line were terminated with matching resistors corresponding to the surge impedance of the multiconductor line. Normally, lightning arresters are attached to the end poles of the three-phase distribution line for all three phases. Currently, Japanese power companies have about three spans (one out of five supports) with one set of three phases. Since there is a track record of installing lightning arresters, three-phase lightning arresters are attached to the end pillars of the three-phase distribution line in line with such a situation. 160m), a lightning arrester was attached to all phases of the distribution line, and an analysis circuit for grounding (ground resistance Ra of 30Ω) was set (see FIGS. 6 and 7).
[0025]
Other lightning arresters were attached to the other supports with one phase omitted, and the phase where the lightning arresters were omitted was different between the three-phase distribution line and the single-phase distribution line so that a ground fault short circuit between different columns would occur. . The grounding of the lightning arrester was connected to the grounding resistance Rb (150Ω) of the support in consideration of the fact that the buried portion of the support becomes a grounding electrode against lightning. The grounding of the overhead ground wire and the suspension wire for the communication line was connected to the grounding resistance Ra of the lightning arrester for the support with the lightning arrester, and the grounding resistance Rb of the support with the lightning arrester was connected to the grounding resistance Rb of the support. The lightning strike point is the top of the support for the end pillar of the three-phase distribution line in the distribution line with no overhead ground line, and the top of the support for the end column of the three-phase distribution line in the distribution line with no overhead line (see Table 1). ).
[0026]
[Table 1]

[0027]
On the other hand, the analysis environment for branching and extending a single-phase distribution line from the middle of a three-phase distribution line with a two-phase lightning arrester is as follows: Similarly, the distribution line was terminated with a matching resistor corresponding to the surge impedance of the multiconductor line at each of the three termination portions (see FIG. 8). The lightning strike point was the top of the support of the three-phase distribution line where the single-phase distribution line branches from the three-phase distribution line.
[0028]
Constants such as line resistance and inductance were calculated using the EMTP JMARI setup subprogram. The lightning current waveform directly hitting the distribution line is a triangular waveform with a wave tail length of 70 μs as shown in FIG. 9, and the lightning current wavefront length and the lightning current peak value that affect the lightning overvoltage generated in the distribution line are parameters (used for analysis). The lightning current waveform parameters were changed as shown in Table 2 below, and the lightning short-circuit damage rate was calculated as follows. As for the occurrence of a ground fault short circuit between different columns, it was assumed that a short circuit would occur when a breakdown occurs simultaneously in the lightning arrester omitted phase of the three-phase distribution line and the lightning arrester omitted phase of the single-phase distribution line. (Possibility of natural arc extinction is not considered.)
[0029]
[Table 2]

[0030]
The calculation method of lightning short-circuit damage rate is as follows. First, for each analysis circuit, for each wavefront length of the lightning current, the minimum lightning current peak value that causes a short-circuit between different pillars is obtained, and the lightning current wave peak length and lightning current peak value that cause lightning short-circuit damage are calculated. The relationship is obtained (see FIG. 10). Then, in the relational curve of FIG. 10, the probabilities of the wavefront length Tf and the peak value Ip of the lightning current are obtained based on Table 2 for the range (shaded area in FIG. 10) on the side exceeding the threshold at which lightning short-circuit damage occurs. If integrated, the lightning short-circuit damage rate Pf can be obtained (see Equation 1). Here, the probability density function of the logarithmic value of the lightning strike current wavefront length and the probability density function of the logarithmic value of the lightning strike current peak value are calculated according to a normal distribution and are independent.
[0031]
[Expression 1]

[0032]
As a result of analysis based on the above environment and conditions, if lightning arresters of a certain phase are omitted for all utility poles in a single-phase distribution line as shown in FIG. 11, the lightning short-circuit damage rate of the line without the overhead ground line is 7.5%, the overhead ground line If the lightning arrester is attached to all phases with the first support and the second support of the single-phase distribution line, the lightning short-circuit damage rate will be up to 0.1% regardless of the presence of overhead ground wires It can be seen that it can be reduced.
[0033]
In addition, in the line without the overhead ground wire in FIG. 12, the lightning short-circuit damage rate when the lightning arrester for one phase of all the single-phase distribution lines is omitted is 14.4%, and the three-phase distribution line to which the single-phase distribution lines are connected It can be seen that the lightning short-circuit damage rate can be reduced to 1.0% when lightning arresters are attached to all phases at the three points of the support, the first support of the single-phase distribution line and the second support of the single-phase distribution line.
[0034]
In addition, in the analysis when branching and extending a single-phase line from the middle of a three-phase distribution line with a lightning arrester in two phases, the analysis result in the case of single-phase extension from a three-phase terminal column with a three-phase lightning arrester The result is that there is no overhead ground wire and there is a suspension line for communication lines. Only to consider.
[0035]
【The invention's effect】
As described above, according to the lightning damage protection method for a single-phase distribution line according to the present invention, even if one phase of the lightning protection device is omitted in the three-phase distribution line, the lightning damage is drawn from the three-phase distribution line. For single-phase distribution lines, when one of the lightning arresters is omitted, dielectric breakdown occurs between the phase where the lightning arrester of the three-phase distribution line is omitted and the phase where the lightning arrester of the drawn single-phase distribution line is omitted. Low-cost single-phase distribution line that can effectively reduce the possibility of a short-circuit ground fault through different pillars due to the occurrence of a fault and can eliminate the installation of a lightning arrester while maintaining a low lightning short-circuit damage rate Will contribute to the provision of
[Brief description of the drawings]
FIGS. 1A and 1B are model diagrams showing a first embodiment and a second embodiment of a lightning damage protection method for a single-phase distribution line according to the present invention.
FIGS. 2A and 2B are model diagrams showing a third embodiment and a fourth embodiment of a lightning damage protection method for a single-phase distribution line according to the present invention.
FIGS. 3A and 3B are model diagrams showing a fifth embodiment and a sixth embodiment of a lightning damage protection method for a single-phase distribution line according to the present invention.
4A and 4B are model diagrams showing a seventh embodiment and an eighth embodiment of a lightning damage protection method for a single-phase distribution line according to the present invention.
5A and 5B are model diagrams showing a ninth embodiment and a tenth embodiment of a lightning damage protection method for a single-phase distribution line according to the present invention.
6A and 6B are a model diagram and an equivalent circuit diagram showing an example of an analysis circuit of a lightning damage protection method for a single-phase distribution line according to the present invention.
7A and 7B are a model diagram and an equivalent circuit diagram showing an example of an analysis circuit of a lightning damage protection method for a single-phase distribution line according to the present invention.
FIGS. 8A and 8B are a model diagram and an equivalent circuit diagram showing an example of an analysis circuit of a lightning damage protection method for a single-phase distribution line according to the present invention.
FIG. 9 is a graph showing an example of a lightning current waveform directly hitting a distribution line used for analysis of a lightning damage protection method for a single-phase distribution line according to the present invention.
FIG. 10 is a graph showing an example of the relationship between the wavefront length of the lightning strike current and the peak value of the lightning strike current in the analysis circuit.
FIG. 11 is a graph showing a lightning short-circuit damage rate according to a countermeasure method when a single-phase extension is performed from a three-phase end pole with a three-phase lightning arrester.
FIG. 12 is a graph showing lightning short-circuit damage rates according to countermeasures when a single-phase distribution line is branched and extended from the middle of a three-phase distribution line with a two-phase lightning arrester.

Claims

The starting point of the single-phase distribution line, which is drawn from the three-phase distribution line where the installation of the lightning arrester of only one phase is omitted for all utility poles, excluding the phase where the installation of the lightning arrester is omitted Attach the lightning arrester to all phases of at least the first utility pole counted from the above, and to all phases of the utility pole that is the extraction point of the single-phase distribution line in the three-phase distribution line, and in the single-phase distribution line A method for protecting a lightning breakage of a single-phase distribution line that omits the installation of the lightning arrester of only one phase, which is defined for a power pole after a power pole having a lightning arrester attached to all phases.

A single phase is constructed by pulling out two phases excluding the phase where the installation of the lightning arrester is omitted from the three-phase distribution line where the installation of the lightning protection device of only one phase specified for all the power poles is omitted for all or part of it. Attaching the lightning arrester to all phases of at least the first utility pole counted from the starting point of the phase distribution line, and to all phases of the utility pole as the pull-out point of the single-phase distribution line in the three-phase distribution line, A lightning break protection method for a single-phase distribution line that omits the installation of only one phase of the lightning arrester defined for all or a part of the utility poles after the power pole with the lightning protection apparatus attached to all phases in the single-phase distribution line.