JP4744492B2 - Measurement method for thermal history of transmission lines - Google Patents
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Description
本発明は、送電線の熱履歴測定方法に関する。 The present invention relates to a thermal history measuring how the transmission line.
一般に、屋外等に架線される送電線は、経年劣化するため、所定の条件に基づいてその余寿命が判断されて、撤去・交換が行われる。送電線の劣化を招く原因としては、長年繰返し加わる曲げによる疲労、腐食、通電による発熱、或いは雷撃等による損傷などが挙げられるが、これらの内でも、通電による発熱の影響（以下、「熱履歴」という）は、送電線全体の引っ張り強さを低下させ、設備の設計上、必要な強度に対する余裕度を減少させ、余寿命を減少させる大きな原因とされている。 In general, a power transmission line installed outdoors or the like deteriorates over time, and therefore, the remaining life is determined based on a predetermined condition, and is removed or replaced. The causes of deterioration of power transmission lines include fatigue due to bending repeatedly applied for many years, corrosion, heat generation due to energization, damage due to lightning strikes, etc. Among these, the influence of heat generation due to energization (hereinafter referred to as “thermal history”) Is said to be a major cause of reducing the tensile strength of the entire transmission line, reducing the margin for the required strength, and reducing the remaining life in the design of the equipment.
引張り強さの低下は，高温になるほど短時間で進行する。そこで、引張り試験による送電線の強度検査が、発熱による熱履歴を測定する方法として、直接的かつ簡便な手段として行われている（「電気学会技術報告 第６６０号 架空送電線の電流容量 （１９９７）」）（非特許文献１）。
しかし、前記引張り強さの測定は、一般に撚り線で提供される送電線を、そのまま引張り試験機にセットして行われるわけではなく、通常は、通電を分担する素線を直線状に撚りを戻した後に試験機にセットして行われる。このため、引張り試験を行う前に、素線の撚りを戻して直線状に加工する必要がある。この際、素線に転位が生じるため、得られた引張り強さは、測定前の測定対象物についての正確な引張り強さとは、一致しない。 However, the measurement of the tensile strength is not usually performed by setting a transmission line provided by a twisted wire as it is in a tensile tester, and usually a strand that shares power is twisted linearly. After returning, it is set on the testing machine. For this reason, before conducting a tensile test, it is necessary to untwist the strands and process them into a straight line. At this time, since dislocation occurs in the strand, the obtained tensile strength does not match the exact tensile strength of the measurement object before measurement.
また、経年変化による腐食や、施工時の傷などがあると、送電線の素線の断面積が部位により異なるため、引張り荷重は求めることはできても、引張り強さを正確に求めることができない。 In addition, if there is corrosion due to secular change or damage during construction, the cross-sectional area of the transmission wire differs depending on the part, so the tensile strength can be obtained accurately even though the tensile load can be obtained. Can not.
このように、従来の引張り試験による測定法では、送電線の経年後における引張り強さを正確に把握することができず、結果的に、送電線の熱履歴が正確に測定できないという問題がある。 As described above, the conventional measurement method based on the tensile test cannot accurately grasp the tensile strength of the transmission line after aging, and as a result, there is a problem that the thermal history of the transmission line cannot be measured accurately. .
送電線の熱履歴は、個々の送電状況や、周囲の気象条件によっても大きく左右される。例えば、寒冷地の送電線や、主として寒冷期に使用されている送電線などの場合には、熱の影響が、他の場所、時期に使用されている送電線の場合に比べて小さく、温暖な場所では逆となるため、熱影響による劣化の程度を測定する場合、これらを考慮して測定し、評価を行う必要がある。 The heat history of the transmission line is greatly affected by the individual power transmission situation and the surrounding weather conditions. For example, in the case of a transmission line in a cold region or a transmission line that is mainly used in the cold season, the influence of heat is smaller than that of a transmission line used in other places and times. Since the opposite is true at a certain place, when measuring the degree of deterioration due to thermal influence, it is necessary to take into account these and perform evaluation.
また、近年、送電線の運用は、供給安定の他、経済的効率向上も勘案することが要請されるようになり、厳しさが増して来ている。このため、送電線の電流容量を、従来よりも増やして運用する事例が増加してきている。送電線の電流容量を増やせば、電流による発熱量が増加する。従来は、送電線の電流容量について、かなり余裕を持った条件で設定されていたため、送電線が電流による発熱で、実際に熱的に劣化する確率は非常に低かったが、電流容量の増加に伴い、設定条件における余裕度が減少して、熱的に劣化する確率が高まってきたと言える。また、事故対応等の短期的な運用では、計算上送電線の熱劣化を生じる可能性のあるような大電流送電を強いられることも増えてきている。このため、従来よりも、送電線の熱劣化の発生を正確に検証する必要性が高まっている。 Moreover, in recent years, the operation of transmission lines has become increasingly demanding, taking into account the improvement of economic efficiency in addition to stable supply. For this reason, the case where the current capacity of a transmission line is increased and operated is increasing. Increasing the current capacity of the transmission line increases the amount of heat generated by the current. In the past, the current capacity of the transmission line was set under conditions that had a considerable margin, so the probability that the transmission line actually generated heat due to heat generation was very low, but the current capacity increased. Accordingly, it can be said that the margin in the setting conditions has decreased and the probability of thermal degradation has increased. Also, in short-term operations such as accident response, there is an increasing number of compulsory high-current power transmissions that may cause thermal degradation of transmission lines. For this reason, the necessity to verify correctly generation | occurrence | production of the thermal degradation of a transmission line is increasing rather than before.
このため、送電線に転位が生じない方法により、送電線を実運用にできるだけ近い状態のもとで、送電線に断面積の変化が生じていても、熱影響が比較的小さい送電線を含めて、送電線の熱履歴の状況を正確に測定する方法の開発が求められている。さらに、その測定結果に基づき、送電線の余寿命を正確に判断する余寿命測定方法の開発が求められている。 For this reason, even if there is a change in the cross-sectional area of the transmission line in a state where the transmission line is as close as possible to actual operation by a method that does not cause dislocation in the transmission line, Therefore, there is a need to develop a method for accurately measuring the thermal history of transmission lines. Furthermore, there is a need for the development of a remaining life measurement method that accurately determines the remaining life of a transmission line based on the measurement results.
本発明者は、上記課題に鑑み鋭意検討の結果、従来、金属（導体）の不純物量を測定する手段として用いられていた残留抵抗比が、送電線の熱履歴を測定するのに好適な指標であることを見出した。 As a result of intensive studies in view of the above problems, the present inventor is an index suitable for measuring the thermal history of a transmission line, which is a residual resistance ratio that has been conventionally used as a means for measuring the amount of impurities in a metal (conductor). It was Heading that is.
即ち、本発明は、第１の技術として、残留抵抗比を用いて、送電線の熱履歴を測定することを特徴とする送電線の熱履歴測定法を提供する。 That is, the present invention provides , as a first technique, a method for measuring the thermal history of a transmission line, which measures the thermal history of the transmission line using a residual resistance ratio.
ここで、残留抵抗比とは、常温での電気抵抗値（Ｒｔ）と、絶対零度での電気抵抗値（Ｒｏ）以下、「残留抵抗値」という）との比である。
一般に、常温（ｔ℃）における金属（導体）の抵抗値Ｒｔは、格子欠陥による抵抗値Ｒｄ、不純物の影響による抵抗値Ｒｉ、及び格子振動による抵抗値Ｒｖの総和として、下式（１）のように表される。
Here, the residual resistance ratio is a ratio between an electrical resistance value (Rt) at normal temperature and an electrical resistance value (Ro) at absolute zero (hereinafter referred to as “residual resistance value”).
In general, the resistance value R t of a metal (conductor) at normal temperature (t ° C.) is a sum of a resistance value R d due to lattice defects, a resistance value R i due to the influence of impurities, and a resistance value R v due to lattice vibration. It is expressed as (1).
Ｒｔ＝Ｒｄ＋Ｒｉ＋Ｒｖ＝（ｌ／Ａ）×（ρｄ＋ρｉ＋ρｖ） （１）
ここで、ρｄ、ρｉ、ρｖは、それぞれ、格子欠陥による抵抗率、不純物の影響による抵抗率、金属（導体）の格子振動による抵抗率である。また、ｌは、金属（導体）の長さであり、Ａは、金属（導体）の断面積である。（ｌ／Ａ）と各ρとの積が前記の各抵抗値となる。
Rt = Rd + Ri + Rv = (l / A) * ([rho] d + [rho] i + [rho] v ) (1)
Here, ρ d , ρ i , and ρ v are a resistivity due to lattice defects, a resistivity due to the influence of impurities, and a resistivity due to lattice vibration of a metal (conductor), respectively. L is the length of the metal (conductor), and A is the cross-sectional area of the metal (conductor). The product of (l / A) and each ρ is the resistance value.
この内、格子振動による抵抗値Ｒｖは、絶対零度付近においては、ほぼ０（結晶がほぼ完全な規則性を保っている）であるため、残留抵抗値Ｒ０は、格子欠陥による抵抗値Ｒｄ、及び不純物の影響による抵抗値Ｒｉの和として、下式（２）のように表すことができる。なお、残留抵抗値としては、通常、４．２°Ｋ（液体ヘリウムの温度）における電気抵抗値を使用するが、実用上問題はない。
Ｒ０＝Ｒｄ＋Ｒｉ＝（ｌ／Ａ）×（ρｄ＋ρｉ） （２）
Among this, the resistance value R v due to lattice vibrations, in the vicinity of absolute zero, approximately 0 for (crystals substantially has kept perfect regularity) is, the residual resistance value R 0 is the resistance R due to lattice defects As the sum of d and the resistance value R i due to the influence of impurities, it can be expressed as the following equation (2). As the residual resistance value, an electric resistance value at 4.2 ° K (liquid helium temperature) is usually used, but there is no practical problem.
R 0 = R d + R i = (l / A) × (ρ d + ρ i ) (2)
前記式（１）および（２）より、残留抵抗比Ｘは、下式（３）のように表される。
Ｘ＝（Ｒｔ／Ｒ０）＝（ρｄ＋ρｉ＋ρｖ）／（ρｄ＋ρｉ）＝１＋α （３）
なお、
α＝ρｖ／（ρｄ＋ρｉ） （４）
である。式（３）に示すように、金属（導体）の形状に関する項（ｌ／Ａ）は消去され、残留抵抗比Ｘは、各抵抗率による関係のみで表すことができる（前記非特許文献１、３頁）。
From the expressions (1) and (2), the residual resistance ratio X is expressed as the following expression (3).
X = ( Rt / R0 ) = ([rho] d + [rho] i + [rho] v ) / ([rho] d + [rho] i ) = 1 + [alpha] (3)
In addition,
α = ρ v / (ρ d + ρ i ) (4)
It is. As shown in Equation (3), the term (l / A) relating to the shape of the metal (conductor) is eliminated, and the residual resistance ratio X can be expressed only by the relationship based on each resistivity (Non-Patent Document 1, Page 3).
ここで、
１）格子振動による抵抗率ρｄは、測定温度が同一であれば、同一であること
２）金属（導体）を焼き鈍すことにより、格子欠陥の影響が排除できること
より、残留抵抗比Ｘの変化から、不純物の量の変化を捉えることができる。
here,
1) The resistivity ρ d due to lattice vibration is the same if the measurement temperature is the same. 2) The influence of lattice defects can be eliminated by annealing the metal (conductor), so that the change in the residual resistance ratio X Therefore, the change in the amount of impurities can be captured.
本発明者は、送電線の場合、
１）基本的に経年による不純物量の変化はないこと
２）格子欠陥の量は、熱影響がその殆どを支配していること
３）残留抵抗比の測定には、引張り試験のように、撚りを戻すことや、荷重を加えることによる転位がないこと
４）残留抵抗比は、形状に関する項（ｌ／Ａ）が消えているため、腐食や傷などによって生じる試料形状の如何には影響されないこと
に着目し、前記残留抵抗比が、送電線の熱影響の正確な測定に利用できることを見出した。
In the case of a transmission line, the present inventor
1) Basically, there is no change in the amount of impurities due to aging. 2) The amount of lattice defects is mostly governed by the thermal effect. 3) The residual resistance ratio is measured by twisting as in the tensile test. 4) Residual resistance ratio is not affected by the shape of the sample caused by corrosion, scratches, etc., because the term (l / A) related to the shape has disappeared. From the above, it was found that the residual resistance ratio can be used for accurate measurement of the thermal effect of the transmission line.
即ち、前記各抵抗率において、
１）不純物の影響による抵抗率ρｉは、経年変化の前後において、同一であること
２）格子振動による抵抗率ρｖは、測定温度が同一であれば、同一であること
以上のことより、経年変化前後の、あるいは長年の使用による熱履歴の前後の測定において、温度を同一にすれば、残留抵抗比Ｘの変化から、経年変化に伴う格子欠陥による抵抗率ρｄの変化、即ち熱影響（熱履歴）を捉えることができることを見出したのである。
That is, in each resistivity,
1) The resistivity ρ i due to the influence of impurities is the same before and after the secular change. 2) The resistivity ρ v due to the lattice vibration is the same if the measurement temperature is the same. In the measurement before and after the secular change or before and after the thermal history due to long-term use, if the temperature is made the same, the change in the resistivity ρ d due to the lattice defect accompanying the secular change from the change in the residual resistance ratio X, that is, the thermal effect. He discovered that he could capture (thermal history).
以上のように、残留抵抗比は、送電線の熱履歴を測定する指標として好適に用いることができ、経年変化前後の送電線の残留抵抗比を比較することにより、経年変化による熱影響を知ることができる。 As described above, the residual resistance ratio can be suitably used as an index for measuring the thermal history of the transmission line. By comparing the residual resistance ratio of the transmission line before and after aging, the thermal effect due to aging is known. be able to.
本発明に係る熱履歴測定方法は、従来の引張り試験を用いた熱履歴測定法とは異なり、撚りを戻したりする余分な手順を必要とせず、効率的であるとともに、より正確な測定結果を得ることができる。また、残留抵抗比は、各抵抗率に基づく値であり、形状に関する項（ｌ／Ａ）を含まないため、腐食や傷の発生に伴ってサンプル形状が変化（断面積の変化）しても、残留抵抗比には影響することがなく、信頼性の高い測定結果を得ることができる。さらに、熱影響が比較的小さい送電線に対しても、正確に熱履歴を測定することができる。 Unlike the conventional thermal history measurement method using a tensile test, the thermal history measurement method according to the present invention does not require an extra step of untwisting, is efficient, and provides a more accurate measurement result. Obtainable. The residual resistance ratio is a value based on each resistivity and does not include the term (l / A) relating to the shape, so even if the sample shape changes (changes in cross-sectional area) with the occurrence of corrosion or scratches. The measurement result with high reliability can be obtained without affecting the residual resistance ratio. Furthermore, it is possible to accurately measure the thermal history even for a power transmission line having a relatively small thermal effect.
具体的態様として、本発明は、第２の技術として、測定対象と同じ材質、種類の送電線であって、熱履歴が加えられていない試料に、一定温度で所定時間の熱履歴を加えて、加熱前後における各残留抵抗比を測定し、得られた各残留抵抗比と、測定対象の送電線から得られた試料の残留抵抗比とを用いて、前記測定対象送電線の熱履歴状況を測定することを特徴とする送電線の熱履歴測定方法を提供する。 As a specific aspect, the present invention is a second technique in which a heat history of a predetermined time at a constant temperature is added to a sample that is the same material and type as the measurement object and has no heat history. , Measure the residual resistance ratio before and after heating, and use each residual resistance ratio obtained and the residual resistance ratio of the sample obtained from the transmission line to be measured to determine the thermal history status of the transmission line to be measured. A method for measuring a thermal history of a transmission line is provided.
上記第２の技術に係る熱履歴測定方法の詳細は、以下の通りである。
（熱履歴のない試料の残留抵抗比の測定）
最初に、測定対象と同じ種類の送電線であって、熱履歴が加えられていない試料を用いて、熱履歴のない時点での残留抵抗比Ｘ０を測定する。次に、同じ試料を用いて、一定温度で所定時間加熱する（熱履歴を加える）。加熱条件としては、送電線の設計について一般的に用いられている「短時間電流容量」という設計法に示されている加熱温度、加熱時間を使用することが、後述する送電線の余寿命測定との関係もあり、好ましい。
Details of the thermal history measurement method according to the second technique are as follows.
(Measurement of residual resistance ratio of samples without thermal history)
First, the same type of the transmission line measured, using samples heat history is not applied, measuring the residual resistance ratio X 0 at the time of no heat history. Next, the same sample is heated at a constant temperature for a predetermined time (adding a heat history). As heating conditions, it is possible to use the heating temperature and heating time indicated in the design method called “short-time current capacity”, which is generally used for the design of transmission lines. There is also a relationship with
これは、数年〜数十年の送電線の寿命を短時間の試験で予測する方法であり、具体的には、一定の加熱温度で、一定時間、加熱したときに、引張り強さの値が、加熱前より１０％低下した時点を、送電線寿命の目安として判断するものであり、今日広く業界において採用されている設計法である。実際の運用としては、加熱時間を一律に４００時間と定めておいて、その４００時間加熱で引張り強さを１０％低下させる加熱温度として、送電線の種類により、それぞれの材料の耐熱特性に応じて、以下のように決められている。
・ＥＣＡｌ （電気用アルミニウム材、純度９９．７％）：１２０℃
・６０ＴＡｌ（６０％導電率耐熱アルミニウム合金） ：１８０℃
・ＺＴＡｌ （超耐熱アルミニウム合金） ：２１０℃
・ＸＴＡｌ （超々耐熱アルミニウム合金） ：３００℃
This is a method of predicting the life of a transmission line from several years to several tens of years in a short test. Specifically, when it is heated at a constant heating temperature for a certain time, the tensile strength value is calculated. However, it is determined as a measure of the life of the power transmission line when the temperature is 10% lower than before heating, and is a design method widely used in the industry today. In actual operation, the heating time is uniformly set to 400 hours, and the heating temperature at which the tensile strength is reduced by 10% by heating for 400 hours depends on the heat resistance characteristics of each material depending on the type of transmission line. Is determined as follows.
ECAl (electrical aluminum material, purity 99.7%): 120 ° C
60TAl (60% conductivity heat resistant aluminum alloy): 180 ° C
・ ZTAI (super heat resistant aluminum alloy): 210 ° C
・ XTAl (super heat resistant aluminum alloy): 300 ° C
以上に基づき、測定対象の送電線の種類・耐熱特性に対応した加熱温度で、４００時間加熱する。加熱後、残留抵抗比Ｘ４００を測定する。この４００時間加熱後の残留抵抗比Ｘ４００は、即ち劣化の限界（寿命）における残留抵抗比ＸＭＡＸを意味しており、加熱前後での残留抵抗比の差（Ｘ４００−Ｘ０）が、寿命時点における劣化状況を示している。 Based on the above, heating is performed for 400 hours at a heating temperature corresponding to the type and heat resistance characteristics of the transmission line to be measured. After heating, the residual resistance ratio X400 is measured. The residual resistance ratio X 400 after heating for 400 hours means the residual resistance ratio X MAX at the limit of deterioration (life), and the difference in residual resistance ratio before and after heating (X 400 -X 0 ) It shows the deterioration status at the end of life.
（測定対象試料による残留抵抗比測定）
次に、測定対象の送電線から得られた試料を用いて、熱履歴後の残留抵抗比Ｘｔを測定する。測定対象の送電線の残留抵抗比と、前記熱履歴が加えられていない送電線の残留抵抗比の差（Ｘｔ−Ｘ０）が、測定対象の送電線の測定時点における劣化の状況を示している。
(Residual resistance ratio measurement with the sample to be measured)
Next, using samples obtained from a transmission line to be measured, measuring the residual resistance ratio X t after thermal history. The difference between the residual resistance ratio of the transmission line to be measured and the residual resistance ratio of the transmission line to which the thermal history is not applied (X t −X 0 ) indicates the state of deterioration at the time of measurement of the transmission line to be measured. ing.
（測定対象試料の熱履歴測定）
そして、２つの残留抵抗比の差から、その比｛（Ｘｔ−Ｘ０）／（Ｘ４００−Ｘ０）｝×１００％を求めると、これが測定対象試料の劣化の程度を示す指標として、熱履歴の状況を示す。
(Measurement of thermal history of sample to be measured)
Then, when the ratio {(X t −X 0 ) / (X 400 −X 0 )} × 100% is obtained from the difference between the two residual resistance ratios, this is an index indicating the degree of deterioration of the measurement target sample. Shows the status of thermal history.
前記の測定においては、測定対象の送電線と同じ材質、種類の送電線であって、熱履歴が加えられていない（経年変化前）試料が、用意される必要がある。それには、同一品を新品のまま保存しておいて、測定時、それを用いて、加熱前の残留抵抗比Ｘ０及び加熱後の残留抵抗比Ｘ４００を得る方法や、新品の時点で、予め、加熱前の残留抵抗比Ｘ０及び加熱後の残留抵抗比Ｘ４００を得ておく方法があるが、管理の煩雑さ等、実務上では、困難な場合が多い。 In the above-described measurement, it is necessary to prepare a sample that is the same material and type as the transmission line to be measured and has no heat history (before aging). To do this, saved the same dish remains new, time of measurement, by using the same, and a method of obtaining a residual resistance ratio X 0 and residual resistance ratio X 400 after heating before heating, at the time of new, previously, there is a way to keep obtaining a residual resistance ratio X 0 and residual resistance ratio X 400 after heating before heating, complexity, etc. of the management, the practice is often difficult.
本発明者は、前記新品試料に換えて、加熱前の残留抵抗比Ｘ０及び加熱後の残留抵抗比Ｘ４００を得るために適当な試料につき検討した結果、送電線に装着される接続管や、クランプなどの接続部品の質量、形状が、電線よりはるかに大きく、接続管やクランプの熱放散が大きいことに着目した。 The present inventors, the place of the new sample, the residual before heating resistance ratio X 0 and a result of studies on appropriate samples to obtain a residual resistance ratio X 400 after heating, connection tube Ya mounted in the transmission line We focused on the fact that the mass and shape of connecting parts such as clamps are much larger than those of electric wires, and that heat dissipation of connecting pipes and clamps is large.
送電線は、通常、２０００〜３０００ｍの１連続長の電線を接続して使用されるが、数百ｍ毎に鉄塔（懸垂鉄塔または耐張鉄塔）が設置されて、電線が支持される。このとき、接続では接続管が、懸垂鉄塔では懸垂クランプが、耐張鉄塔では耐張クランプが電線に装着されて、電線を支持する。 The power transmission line is usually used by connecting one continuous length of 2000 to 3000 m, and a steel tower (a suspended steel tower or a tension steel tower) is installed every several hundred meters to support the electric wire. At this time, the connection pipe is attached to the electric wire, the suspension clamp is attached to the electric suspension tower, and the tension clamp is attached to the electric wire to support the electric wire.
接続管やクランプの質量は電線よりはるかに大きいため、接続管やクランプは加熱され難く、また熱放散も大きくなるため、送電線に電流を流したとき、係る部位における温度上昇は、送電線の半分程度とされている。そして、送電線においては、少しの温度低下でも寿命が大きく伸びることが分かっている（アルミ電線標準専門委員会、「大電流電線」電気協同研究３２、Ｎｏ１、１９７６）ため、上記の部品の装着部は、一般電線部に比べると実質的には、「熱劣化が生じていない部分」と言える。
Since the mass of the connecting pipe and clamp is much larger than that of the electric wire, the connecting pipe and clamp are difficult to heat and the heat dissipation is also large. It is said to be about half. In addition, it has been found that the life of a power transmission line is greatly increased even with a slight decrease in temperature (Aluminum Wire Standards Special Committee, “Large Current Wire”
温度と寿命との関係について一例を挙げると、ＥＣＡｌでは、１２０℃、４００時間の加熱で１０％引張り強さが低下（劣化）するが、９０℃の加熱温度では３６年で１０％である。仮に部品の装着部の温度が６０℃とすると、１０％引張り強さが低下するには、数百年を要するということになり、通常の使用条件では熱的な影響は殆どないと判断してもかまわない。 As an example of the relationship between temperature and life, ECAl decreases (deteriorates) the tensile strength by 10% by heating at 120 ° C. for 400 hours, but it is 10% by 36 years at a heating temperature of 90 ° C. If the temperature of the part mounting part is 60 ° C., it will take several hundred years to reduce the 10% tensile strength, and it is judged that there is almost no thermal influence under normal use conditions. It doesn't matter.
以上のことより、接続管やクランプなどの接続部品近傍は、実質的に熱履歴が加えられていない箇所と判断しても問題はない。第３の技術（請求項１）は、この好ましい態様であって、熱履歴が加えられていない試料として、測定対象の送電線に接続されているが、実質的に熱履歴を受けない箇所から採取した試料を用いることを特徴とする送電線の熱履歴測定方法を提供する。 From the above, there is no problem even if it is determined that the vicinity of the connection parts such as the connection pipe and the clamp is a place where the heat history is not substantially applied. The third technique (Claim 1) is this preferred embodiment, and is connected to the transmission line to be measured as a sample to which no thermal history is applied, but from a location that does not substantially receive the thermal history. Provided is a method for measuring thermal history of a transmission line, characterized by using a collected sample.
また、避雷器への分岐などは、回路構成上、電流がわずかしか流れない部分であり、もともと熱履歴を受けない箇所であるため、その近傍の電線を熱履歴前の送電線として使用してもよい。第４の技術（請求項２）は、この好ましい態様であって、熱履歴が加えられていない試料として、測定対象の送電線に接続されているが、実質的に電気が流れず、このため熱履歴を受けない箇所から採取した試料を用いることを特徴とする送電線の熱履歴測定方法を提供する。 In addition, branching to a lightning arrester is a part where only a small amount of current flows in the circuit configuration and is originally a part that does not receive thermal history, so even if a nearby wire is used as a transmission line before thermal history Good. The fourth technique (Claim 2) is this preferred embodiment, and is connected to the transmission line to be measured as a sample to which no thermal history is applied. Provided is a method for measuring the thermal history of a power transmission line, characterized by using a sample collected from a location not receiving thermal history.
このように、送電線の残留抵抗比を用いることにより、劣化の状況を測定できることが分かったが、送電線の管理者は、劣化の状況からその余寿命を判断して、いつ送電線を撤去・交換すべきかを具体的に把握する必要がある。 In this way, it was found that the degradation condition can be measured by using the residual resistance ratio of the transmission line, but the transmission line manager determines the remaining life from the degradation condition, and when the transmission line is removed・ It is necessary to grasp in detail whether to replace.
本発明者は、熱履歴が加えられていない試料を用いて、一定温度で所定時間加熱する（熱履歴を加える）際、加熱経過途中において残留抵抗比を測定しておけば、送電線の残留抵抗比を測定すると同時に、該送電線の余寿命を判定できることを見出した。 The present inventor uses a sample to which no thermal history is applied and heats it for a predetermined time at a constant temperature (adds the thermal history), and if the residual resistance ratio is measured in the course of heating, the transmission line remains. It has been found that the remaining life of the transmission line can be determined simultaneously with measuring the resistance ratio.
即ち、本発明者は、第５の技術として、熱履歴が加えられていない試料に、一定温度で所定時間の熱履歴を加えて、加熱経過時間と残留抵抗比の変化を、予めマスターデータとして求めておき、測定対象の送電線から得られた試料の残留抵抗比と、前記マスターデータにおける残留抵抗比との一致点を求め、それに対応した加熱時間から、前記測定対象の送電線の余寿命を判定することを特徴とする送電線の余寿命測定方法を提供する。 That is, as a fifth technique , the present inventor adds a heat history for a predetermined time at a constant temperature to a sample to which no heat history has been added, and preliminarily changes the heating elapsed time and the residual resistance ratio as master data. Obtain the remaining resistance ratio of the sample obtained from the transmission line to be measured and the residual resistance ratio in the master data, and calculate the remaining life of the transmission line from the corresponding heating time. A method for measuring the remaining life of a transmission line is provided.
本請求項に係る余寿命測定法の詳細は、以下の通りである。
（マスターデータの収集）
最初に、マスターデータを収集する。具体的には、熱履歴が加えられていない（経年変化前）あるいは実質的に熱履歴が加えられていない試料を用いて、一定温度で所定時間加熱する（熱履歴を加える）。加熱条件としては、上述した「短時間電流容量」設計法に示されている加熱温度、加熱時間を使用する。
The details of the remaining life measuring method according to the present claims are as follows.
(Master data collection)
First, collect master data. Specifically, using a sample to which no heat history is applied (before aging) or substantially no heat history is applied, heating is performed at a constant temperature for a predetermined time (adding a heat history). As the heating conditions, the heating temperature and the heating time shown in the above-described “short-time current capacity” design method are used.
測定対象の送電線の種類・耐熱特性に対応した加熱温度で、加熱時間を４００時間まで変化させて、途中、加熱経過時間に対する残留抵抗比を順次測定して、マスターデータとする。具体的事例として、図１を挙げる。図１は、得られたマスターデータを、加熱経過時間を横軸、残留抵抗比を縦軸として、表１に示す加熱経過時間毎のデータをプロットしたものである。各データを結んだ曲線を、以下「マスターカーブ」という。 At the heating temperature corresponding to the type and heat resistance characteristics of the transmission line to be measured, the heating time is changed up to 400 hours, and the residual resistance ratio with respect to the heating elapsed time is sequentially measured to obtain master data. A specific example is shown in FIG. FIG. 1 is a plot of the master data obtained with the elapsed time of heating shown in Table 1 plotted with the elapsed time of heating as the horizontal axis and the residual resistance ratio as the vertical axis. The curve connecting the data is hereinafter referred to as “master curve”.
（測定対象試料による残留抵抗比測定）
次に、測定対象の送電線から得られた試料を用いて、その残留抵抗比を測定する。
(Residual resistance ratio measurement with the sample to be measured)
Next, the residual resistance ratio is measured using a sample obtained from the transmission line to be measured.
（測定対象試料の熱履歴測定）
そして、得られた測定値と、マスターデータにおける残留抵抗比の一致点を求め、それに対応する加熱時間を測定すれば、同時に当該試料の余寿命を得ることができる。図１を用いて説明すると、４００時間加熱により送電線の寿命と判断するので、測定された残留抵抗比に対応する加熱時間と４００時間との差が、この加熱温度に対応した送電線の余寿命を示していることになる。
(Measurement of thermal history of sample to be measured)
And if the coincidence point of the obtained measured value and the residual resistance ratio in the master data is obtained and the corresponding heating time is measured, the remaining life of the sample can be obtained at the same time. Referring to FIG. 1, since the life of the transmission line is determined by heating for 400 hours, the difference between the heating time corresponding to the measured residual resistance ratio and 400 hours is the surplus of the transmission line corresponding to this heating temperature. It shows the life.
即ち、予め、送電線の種類・耐熱特性に応じた加熱時間でマスターデータを準備しておけば、送電線の残留抵抗比を測定するにより、該送電線の余寿命を直接的に把握することができるので、送電線の撤去・交換時期を容易、かつ正確に判断できて好ましい。 That is, if master data is prepared in advance with the heating time according to the type and heat resistance characteristics of the transmission line, the remaining life of the transmission line can be directly grasped by measuring the residual resistance ratio of the transmission line. Therefore, it is preferable because it is possible to easily and accurately determine when to remove or replace a transmission line.
前述したように、余寿命に十分な余裕があれば、送電線の電流容量を、従来よりも増やして運用することができるが、送電線の電流容量を増やせば、電流による発熱量が増加し、余寿命はより短くなる。加熱温度と電線の寿命の関係については、過去にデータの蓄積があり、送電線の運用条件（周囲温度、送電力）に基づいて送電線がおかれている温度がわかっておれば、容易に余寿命を算定できる。 As described above, if there is a sufficient remaining life, the current capacity of the transmission line can be increased and operated, but if the current capacity of the transmission line is increased, the amount of heat generated by the current increases. The remaining life is shorter. Regarding the relationship between the heating temperature and the life of the wire, if there is data accumulation in the past and the temperature at which the transmission line is placed based on the operating conditions (ambient temperature, power transmission) of the transmission line, it is easy to The remaining life can be calculated.
本発明は、熱履歴を、残留抵抗比を用いて測定するので、従来の引張り強度による測定と異なり、測定試料を撚り戻すといった加工が不要であり、転位も生じないため、実運用に近い状態で、熱履歴の状況を正確に測定することができる。また、残留抵抗比は、測定試料の形状による影響を受けないため、その種類・耐熱温度が同じ送電線であれば、形状が異なる送電線であっても、１つのマスターデータを用いて、熱履歴を正確に測定することができ、極めて有用である。さらに、熱による影響が比較的小さい送電線に対しても適用できる。 In the present invention, since the thermal history is measured using the residual resistance ratio, unlike the conventional measurement by tensile strength, processing such as untwisting the measurement sample is unnecessary and dislocation does not occur. Thus, it is possible to accurately measure the state of the thermal history. In addition, since the residual resistance ratio is not affected by the shape of the measurement sample, if the transmission line has the same type and heat-resistant temperature, even if the transmission lines have different shapes, one master data is used to The history can be measured accurately and is extremely useful. Furthermore, the present invention can be applied to a transmission line that is relatively less affected by heat.
また、本発明は、残留抵抗比から、送電線の余寿命を直接的に把握することができ、送電線の撤去・交換時期を容易、かつ正確に判断でき有用である。 Further, the present invention is useful because it is possible to directly grasp the remaining life of the transmission line from the residual resistance ratio, and to easily and accurately determine the removal / replacement time of the transmission line.
本発明を実施するための最良の形態につき、以下の実施例に基づいて説明する。なお、本発明は、以下の実施の形態に限定されるものではなく、本発明と同一および均等の範囲内において、種々の変更を加えてもよい。 The best mode for carrying out the present invention will be described based on the following examples. In addition, this invention is not limited to the following embodiment, You may add a various change in the same and equivalent range as this invention.
以下の実施例は、測定試料として、ＥＣＡｌ送電線を用いた。なお、測定は、各測定段階において試料数３個を１群として扱い、測定値はその平均値で表す。 In the following examples, an ECAl power transmission line was used as a measurement sample. In the measurement, three samples are treated as one group at each measurement stage, and the measured value is represented by the average value.
（マスターデータの収集）
マスターデータ収集用試料として、クランプ近傍より、長さ２００ｍｍの電線を採取した。試料を、２５℃恒温槽中に１０分間保持し、６Ａ通電したときの電圧Ｖ１を測定した。次いで、試料を、液体ヘリウム（４．２°Ｋ）中に３分間保持し、６Ａ通電したときの電圧Ｖ２を測定した。電流が６Ａと一定なので、加熱経過時間０での残留抵抗比Ｘ０は、
Ｘ０＝（Ｖ１／６）／（Ｖ２／６）＝（Ｖ１／Ｖ２）
により求められる。
(Master data collection)
As a master data collection sample, an electric wire having a length of 200 mm was collected from the vicinity of the clamp. The sample was held in a constant temperature bath at 25 ° C. for 10 minutes, and the voltage V1 when 6 A was energized was measured. Next, the sample was held in liquid helium (4.2 ° K) for 3 minutes, and the voltage V2 when 6 A was energized was measured. Since the current is constant at 6 A, the residual resistance ratio X 0 at the heating elapsed time 0 is
X 0 = (V1 / 6) / (V2 / 6) = (V1 / V2)
It is calculated by.
次いで、１２０℃恒温層の中に試料を静置して、トータルで４００時間加熱した。途中、表１に示す加熱経過時間毎に、１群の試料を取り出し、上記と同様の手順で、各加熱経過時間での残留抵抗比Ｘを求め、マスターデータを得た。結果を表１に示し、それに基づくマスターカーブを図１に示す。なお、図１において、縦軸は残留抵抗比、横軸は加熱経過時間を示す。 Next, the sample was allowed to stand in a 120 ° C. constant temperature layer and heated for a total of 400 hours. In the middle, a group of samples was taken out at every heating elapsed time shown in Table 1, and the residual resistance ratio X at each heating elapsed time was determined by the same procedure as described above to obtain master data. The results are shown in Table 1, and the master curve based on the results is shown in FIG. In FIG. 1, the vertical axis represents the residual resistance ratio, and the horizontal axis represents the elapsed heating time.
（測定対象の送電線試料による残留抵抗比）
上記と同じ材質、種類、サイズの測定対象の送電線試料（経年：２２年）を用いて、上記と同様の手順で、残留抵抗比Ｘｔとして、３１．８６を得た。
(Residual resistance ratio by the transmission line sample to be measured)
The same material as described above, the type, the measurement target of the transmission line sample size (age: 22 years) with, in the same procedure as above, as the residual resistance ratio X t, to obtain a 31.86.
（熱履歴、及び余寿命の測定）
図１の縦軸にＸｔを配し、データとの交点を求め、そこから対応する加熱経過時間を求めると、加熱経過時間Ｔｔとして１６０時間が得られた。４００時間との差（４００−Ｔｔ）が、余寿命であり、余寿命は２４０時間（１２０℃）であることがわかる。熱履歴による劣化の程度は、｛（Ｘｔ−Ｘ０）／（Ｘ４００−Ｘ０）｝×１００％で求め、当初より６５％劣化が進行していることが分かる。
(Measurement of thermal history and remaining life)
When Xt is arranged on the vertical axis of FIG. 1 to obtain the intersection with the data, and the corresponding elapsed heating time is obtained therefrom, 160 hours is obtained as the elapsed heating time Tt . It can be seen that the difference from 400 hours (400−T t ) is the remaining life, and the remaining life is 240 hours (120 ° C.). The degree of deterioration due to thermal history is determined by {(X t −X 0 ) / (X 400 −X 0 )} × 100%, and it can be seen that 65% deterioration has progressed from the beginning.
図１を用いることにより、直接的に、その加熱経過時間（履歴時間）及び余寿命を判定できるため、本方法を用いた判定は、簡便で有用な方法である。 Since the heating elapsed time (history time) and the remaining life can be directly determined by using FIG. 1, the determination using this method is a simple and useful method.
また、種類の異なる送電線毎に、さらに同じ種類の送電線であっても、残留抵抗比に影響を及ぼしやすい不純物量（Ｆｅ、Ｓｉ等）が異なる送電線毎に、予めマスターカーブを作成して、データベース化しておくことにより、測定試料に対応するマスターカーブを迅速に選定できるため、極めて容易に、測定試料の熱劣化の程度を推定することができる。 In addition, a master curve is created in advance for each type of transmission line, and even for the same type of transmission line, for each transmission line that has a different amount of impurities that easily affect the residual resistance ratio (Fe, Si, etc.). By creating a database, the master curve corresponding to the measurement sample can be selected quickly, so the degree of thermal degradation of the measurement sample can be estimated very easily.
Claims (2)
前記熱履歴が加えられていない試料として、測定対象の送電線に接続されているが、実質的に熱履歴を受けない箇所から採取した試料を用いることを特徴とする送電線の熱履歴測定方法。 It was obtained by measuring each residual resistance ratio before and after heating by adding a thermal history for a predetermined time at a constant temperature to a sample that was the same material and type as the measurement target and had no thermal history added. Using each residual resistance ratio and the residual resistance ratio of the sample obtained from the transmission line to be measured, a thermal history measurement method for the transmission line that measures the state of the thermal history of the measurement target transmission line,
A method for measuring the thermal history of a power transmission line, characterized in that a sample collected from a location that is connected to a transmission line to be measured but is not substantially subjected to a thermal history is used as the sample to which no thermal history is applied. .
前記熱履歴が加えられていない試料として、測定対象の送電線に接続されているが、実質的に電気が流れず、このため熱履歴を受けない箇所から採取した試料を用いることを特徴とする送電線の熱履歴測定方法。 It was obtained by measuring each residual resistance ratio before and after heating by adding a thermal history for a predetermined time at a constant temperature to a sample that was the same material and type as the measurement target and had no thermal history added. Using each residual resistance ratio and the residual resistance ratio of the sample obtained from the transmission line to be measured, a thermal history measurement method for the transmission line that measures the state of the thermal history of the measurement target transmission line,
The sample to which the thermal history is not applied is connected to the transmission line to be measured, but substantially no electricity flows, and therefore, a sample collected from a location not receiving the thermal history is used. A method for measuring the thermal history of transmission lines.
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| JP2002260459A (en) * | 2001-03-02 | 2002-09-13 | Sumitomo Wiring Syst Ltd | Method for predicting bending life of electric wire and the like |
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