JPH088017B2 - Power cable - Google Patents
Power cableInfo
- Publication number
- JPH088017B2 JPH088017B2 JP61296610A JP29661086A JPH088017B2 JP H088017 B2 JPH088017 B2 JP H088017B2 JP 61296610 A JP61296610 A JP 61296610A JP 29661086 A JP29661086 A JP 29661086A JP H088017 B2 JPH088017 B2 JP H088017B2
- Authority
- JP
- Japan
- Prior art keywords
- water
- polyethylene
- maleic anhydride
- power cable
- grafted
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
- Graft Or Block Polymers (AREA)
- Organic Insulating Materials (AREA)
Description
【発明の詳細な説明】 (産業上の利用分野) 本発明はポリエチレン電力ケーブルの改良に係るもの
である。DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to improvements in polyethylene power cables.
(従来の技術) ポリエチレンは優れた絶縁性と加工し易さから今日で
は電力ケーブルの絶縁体の主流をなしているものであ
り、特に架橋により熱的特性を向上した架橋ポリエチレ
ンケーブル(XLPEケーブル)は広く汎用されている。(Prior Art) Polyethylene is the mainstream insulator for power cables today due to its excellent insulating properties and ease of processing. In particular, cross-linked polyethylene cables (XLPE cables) with improved thermal properties by cross-linking. Is widely used.
(発明が改良すべき問題点) このXLPEケーブルの弱点は同ケーブル特有の現象とし
て絶縁体中の水分と局部的異常電界の存在によつて水ト
リーが発生し、ケーブルの絶縁性能を低下させる問題が
ある。(Problems to be solved by the invention) The weak point of this XLPE cable is that, as a phenomenon peculiar to the cable, water trees are generated due to the presence of moisture in the insulator and a local abnormal electric field, which reduces the insulation performance of the cable. There is.
XLPE絶縁層中の水トリーは疎水性ポリマーであるポリ
エチレン中に局部的に異常電界があるとそこに水が集中
することによつて起ると考えられる。It is considered that the water tree in the XLPE insulating layer is caused by the concentration of water in the hydrophobic polymer polyethylene when there is a local abnormal electric field.
従つて極性基を有し、ある程度親水性のあるポリマー
をブレンドすることによつて局部的異常電界部に水が集
中するのを防ぎ、耐水トリー性の改善に効果が得られる
ものと考えられる。実際にエチレン酢酸ビニル共重合体
(EVA)やエチレンエチルアクリレート共重合体(EEA)
をブレンドすることによつて、耐水トリー性を改善する
という提案は既に幾つか見受けられる。Therefore, it is considered that by blending a polymer having a polar group and having a certain degree of hydrophilicity, it is possible to prevent water from concentrating on a local abnormal electric field portion, and to improve the water tree resistance. Actually ethylene vinyl acetate copolymer (EVA) and ethylene ethyl acrylate copolymer (EEA)
Some proposals have already been found to improve the water resistance of trees by blending with.
しかし、これらの絶縁組成物であつても水トリー抑止
効果は未だ不完全であり、特に配電クラス電力ケーブル
のように水中に浸漬される状態があるような条件の厳し
い場合はより一層の耐水トリー性の改善が望まれてい
る。However, even with these insulating compositions, the water tree deterrent effect is still incomplete, and even in the case of severe conditions such as being immersed in water such as a power distribution class power cable, a more water resistant tree is obtained. The improvement of sex is desired.
(問題点を解決するための手段) 本発明は上記のような実情に鑑み鋭意検討の結果ポリ
エチレン中に無水マレイン酸をグラフトしたポリエチレ
ンが有効であることを見出した。そして無水マレイン酸
のグラフト量は特に0.05〜5重量%が電力ケーブルとし
て優れた成果を得ることができることを見出した。(Means for Solving Problems) In the present invention, as a result of intensive studies in view of the above-mentioned circumstances, it was found that polyethylene obtained by grafting maleic anhydride onto polyethylene is effective. And, it was found that an excellent result as a power cable can be obtained especially when the grafted amount of maleic anhydride is 0.05 to 5% by weight.
(作用) 上記に於て無水マレイン酸のグラフト量が0.05重量%
未満では水トリー抑制に効果がなく、5重量%を越える
と誘電特性、絶縁抵抗を悪化させるので好ましくない。
無水マレイン酸をグラフト化させるベースポリエチレン
として、低密度ポリエチレン(LDPE)、中密度ポリエチ
レン(MDPE)、高密度ポリエチレン(HDPE)、直鎖状ポ
リエチレン等を用いることができるが、ケーブルへの押
出加工性、絶縁体の可撓性を考慮するとLDPEをベースポ
リエチレンとすることがより望ましいものである。又、
当然のことながら電力ケーブルが高温で使用され、絶縁
体の流動が問題となるような場合は無水マレイン酸グラ
フトポリエチレンも架橋することにより熱的特性を高め
て使用することができる。この場合架橋処理の手段は有
機過酸化物を用いる化学架橋、電子線等の放射線の照射
による架橋及びシラン化剤を用いたシラン架橋のいづれ
によつてもよい。(Function) In the above, the graft amount of maleic anhydride is 0.05% by weight.
If it is less than 5% by weight, the water tree is not suppressed, and if it exceeds 5% by weight, the dielectric properties and insulation resistance are deteriorated.
Low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear polyethylene, etc. can be used as the base polyethylene for grafting maleic anhydride, but extrudability into cables Considering the flexibility of the insulator, it is more desirable to use LDPE as the base polyethylene. or,
As a matter of course, when the power cable is used at a high temperature and the flow of the insulator is a problem, maleic anhydride-grafted polyethylene can also be used by enhancing the thermal characteristics by crosslinking. In this case, the means for the cross-linking treatment may be any of chemical cross-linking using an organic peroxide, cross-linking by irradiation with radiation such as an electron beam, and silane cross-linking using a silanizing agent.
又、本発明の実施に際しては必要に応じて老化防止剤
その他の添加剤を加えることができる。Further, in the practice of the present invention, an antioxidant and other additives can be added if necessary.
(実施例) 以下本発明の実施例を述べる。(Examples) Examples of the present invention will be described below.
例1. 無水マレイン酸グラフト量の種々異なる無水マ
レイン酸グラフト化低密度ポリエチレン(メルトインデ
ックス=1.2)100重量部に、架橋剤としてジクミルパー
オキサイド2.0重量部、老化防止剤として4,4′−チオビ
ス−(6−第3ブチル−3−メチルフエノール)0.2重
量部を加え、混練し、組成物を造つた。Example 1. 100 parts by weight of maleic anhydride-grafted low density polyethylene (melt index = 1.2) having various amounts of maleic anhydride grafted, 2.0 parts by weight of dicumyl peroxide as a cross-linking agent and 4,4′-as an antioxidant. 0.2 parts by weight of thiobis- (6-tert-butyl-3-methylphenol) was added and kneaded to prepare a composition.
各組成物を180℃×10minの条件でプレス成型し、以下
の試験を行なつた。各組成物のプレス成型後の80℃キシ
レン中24hr浸漬乾燥後のゲル分率は85%以上である。Each composition was press-molded under the condition of 180 ° C. × 10 min, and the following tests were conducted. The gel fraction of each composition after immersion molding in 80 ° C. xylene for 24 hours after press molding is 85% or more.
(i) 水トリー試験:第1図に示す如く厚さ5mmの試
験試料1の底面に導電性塗料の塗布層2を設けて接地側
電極とするとともに、試験試料1の上面には水槽4を設
けて水電極を形成し、これに10kV、1kHzの電圧を電圧電
極3より印加できるように構成し、上記電圧を30日間印
加後、試料を煮沸して水トリーを観察し、比較用試料
(現用のXLPE)の発生数100に対する相対数として表示
した。(I) Water tree test: As shown in FIG. 1, a coating layer 2 of a conductive paint is provided on the bottom surface of a test sample 1 having a thickness of 5 mm to serve as a ground side electrode, and a water tank 4 is mounted on the top surface of the test sample 1. A water electrode is provided to form a water electrode, and a voltage of 10 kV and 1 kHz is applied to the voltage electrode 3 from the voltage electrode 3. After applying the above voltage for 30 days, the sample is boiled to observe a water tree, and a comparative sample ( It is shown as a relative number to 100 occurrences of the current XLPE).
(ii) 誘電正接(tan δ)測定:1mm厚シートに1kV 50
Hz電圧を印加し、シエーリングフリツジにより測定し
た。(Ii) Dielectric loss tangent (tan δ) measurement: 1kV 50 on 1mm thick sheet
A Hz voltage was applied and the measurement was carried out by a shearing frit.
上記各試験をした結果は第1表に示すとおりである。 The results of each of the above tests are shown in Table 1.
(実施例2) 表1の試料No.1及びNo.4の組成物を用いて絶縁体とし
た電力ケーブルを作つた。 (Example 2) Using the compositions of Sample No. 1 and No. 4 in Table 1, a power cable having an insulator was made.
ケーブル構造は導体断面積200mm2、絶縁厚3mm、内部
押出半導電槽、外部押出半導電層を有する3層構成から
なるもので、外部に施す遮蔽やシースは省略した。The cable structure has a conductor cross-sectional area of 200 mm 2 , an insulation thickness of 3 mm, an internally extruded semiconductive tank, and an externally extruded semiconductive layer.
上記各ケーブルについて以下の浸水課電試験を行なつ
た結果を第2表に示す。Table 2 shows the results of conducting the following flooding and charging test on each of the above cables.
浸水課電試験:導体注水有の条件で70℃の温水中で1k
Hz、10kVの電圧を90日間印加後、AC(50Hz)の電圧を5k
V/30minのステツプアツプの条件で昇圧して破壊電圧を
求める。Flooding voltage test: 1k in hot water at 70 ° C with conductor injection
After applying the voltage of 10Hz for 10 days at 90Hz, the voltage of AC (50Hz) is 5k
Step up under V / 30min step-up condition to obtain breakdown voltage.
(発明の効果) 本発明は以上の比較試験から判るように、絶縁体を構
成する組成物として、所定量の無水マレイン酸をグラフ
ト化した無水マレイン酸グラフトポリエチレンを使用す
ることによつて水トリーの発生を著しく抑制することが
でき浸水課電後の破壊電圧の低下を防ぐことができる。 (Effects of the Invention) As can be seen from the above comparative tests, the present invention shows that a water tree is prepared by using a maleic anhydride-grafted polyethylene grafted with a predetermined amount of maleic anhydride as a composition constituting an insulator. It is possible to remarkably suppress the generation of water and prevent a decrease in breakdown voltage after the application of water.
第1図は水トリー試験の説明図である。 1:試料、2:導電塗料 3:高圧電極、4:水道水 FIG. 1 is an explanatory diagram of a water tree test. 1: Sample, 2: Conductive paint 3: High voltage electrode, 4: Tap water
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭62−100909(JP,A) 特開 昭60−56312(JP,A) 特開 昭61−53611(JP,A) ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP 62-100909 (JP, A) JP 60-56312 (JP, A) JP 61-53611 (JP, A)
Claims (2)
が0.05〜5重量%である無水マレイン酸グラフトポリエ
チレン組成物を用いた絶縁層を構成したことを特徴とす
る電力ケーブル1. A power cable characterized in that an insulating layer made of a maleic anhydride grafted polyethylene composition having a maleic anhydride graft amount of 0.05 to 5% by weight is formed on the outside of a conductor.
ベースポリエチレンは低密度ポリエチレンであり、かつ
絶縁層は架橋されて形成されていることを特徴とする特
許請求の範囲第1項記載の電力ケーブル2. The power cable according to claim 1, wherein the base polyethylene of maleic anhydride-grafted polyethyllene is low-density polyethylene, and the insulating layer is formed by crosslinking.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61296610A JPH088017B2 (en) | 1986-12-15 | 1986-12-15 | Power cable |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61296610A JPH088017B2 (en) | 1986-12-15 | 1986-12-15 | Power cable |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS63150810A JPS63150810A (en) | 1988-06-23 |
JPH088017B2 true JPH088017B2 (en) | 1996-01-29 |
Family
ID=17835784
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61296610A Expired - Lifetime JPH088017B2 (en) | 1986-12-15 | 1986-12-15 | Power cable |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH088017B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE69923086D1 (en) | 1998-09-16 | 2005-02-10 | Japan Polyolefins Co Ltd | USE OF AN ELECTRICAL INSULATION RESIN MATERIAL AND ELECTRICAL CABLE AND CABLE THEREOF USED THEREOF |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5531854A (en) * | 1978-08-28 | 1980-03-06 | Nippon Kasei Kk | Crosslinkable composition |
JPS6036217B2 (en) * | 1981-04-07 | 1985-08-19 | 東亜燃料工業株式会社 | Modified polyethylene composition |
JPS5915437A (en) * | 1982-07-20 | 1984-01-26 | Nippon Kasei Kk | Polyolefin composition |
-
1986
- 1986-12-15 JP JP61296610A patent/JPH088017B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS63150810A (en) | 1988-06-23 |
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