EP0508647A2 - Unterbrechungseinheit - Google Patents

Unterbrechungseinheit Download PDF

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Publication number
EP0508647A2
EP0508647A2 EP92302553A EP92302553A EP0508647A2 EP 0508647 A2 EP0508647 A2 EP 0508647A2 EP 92302553 A EP92302553 A EP 92302553A EP 92302553 A EP92302553 A EP 92302553A EP 0508647 A2 EP0508647 A2 EP 0508647A2
Authority
EP
European Patent Office
Prior art keywords
container
wall
linear resistors
arrestor
arrestor unit
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.)
Granted
Application number
EP92302553A
Other languages
English (en)
French (fr)
Other versions
EP0508647B1 (de
EP0508647A3 (en
Inventor
Tetsuya Nakayama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NGK Insulators Ltd
Original Assignee
NGK Insulators Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NGK Insulators Ltd filed Critical NGK Insulators Ltd
Publication of EP0508647A2 publication Critical patent/EP0508647A2/de
Publication of EP0508647A3 publication Critical patent/EP0508647A3/en
Application granted granted Critical
Publication of EP0508647B1 publication Critical patent/EP0508647B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/12—Overvoltage protection resistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T1/00—Details of spark gaps
    • H01T1/16—Series resistor structurally associated with spark gap
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T4/00—Overvoltage arresters using spark gaps
    • H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel
    • H01T4/14—Arcing horns

Definitions

  • the present invention relates to arrestor units for power transmission lines. More particularly, the invention relates to an arrestor unit container structure that is arranged to discharge residual electrostatic charges that accumulate in the non-linear resistors.
  • the container structure is capable of discharging the resistors during the surge intervals that occur in multiple surge lightening currents.
  • Japanese Unexamined Patent Publication No. 2-170385 discloses an arrestor unit having a series gap as illustrated in Figs. 4 to 6.
  • Fig. 5 shows the equivalent circuit diagram of the arrestor unit illustrated in Fig. 4.
  • Fig. 6 shows an arrestor unit embodied in accordance with the block diagram illustrated in Fig. 5.
  • the arrestor unit of the prior art has a series gap 51 of an electrostatic capacity C 1 and a non-linear resistor 52(R) in an insulating housing 50.
  • a resistor 53(r) for discharging residual electric charge is electrically connected in parallel with the non-linear resistor 52 respectively through seals 54.
  • the discharge time constant of the arrestor unit depends on the electrostatic capacitance C2 of the resistor 53 and the non-linear resistor 52.
  • the discharge time constant is set to be less than the time interval between voltage surges of a normal multiple surge lightning current.
  • the arrestor unit includes an internal series gap 51, within its insulating housing 50.
  • the operational line voltage is applied to the arrestor unit.
  • the insulator housing 50 it is inevitable that the insulator housing 50 will be subjected to the operational line voltage.
  • the insulating housing 50 should have sufficient insulating strength to withstand the continuous use of the arrestor unit, without current leakage.
  • the resultant arrestor unit is too large in diameter and weight to be easily installed on power transmission lines.
  • an arrestor unit for protecting a power transmission line against lightening surges.
  • the arrestor unit includes a discharge electrode that is electrically separated from the power transmission line by a series air gap.
  • a plurality of non-linear resistors are provided between the discharge electrode and an electrical ground.
  • a container is provided to house the non-linear resistors.
  • the container is arranged to discharge residual electric charges that accumulate in the non-linear resistors.
  • the discharge constant of the container and non-linear resistors is set to a value less than the time interval between voltage surges of a normal multiple surge lightning current.
  • a suspension insulator 9 is suspended from the end of a support arm 2 that extends from a transmission tower 1.
  • a power transmission line 5 is supported by the bottom part of the suspension insulator 3 via a support 4.
  • Arc horns 6 and 7 are attached to the top and bottom ends of the suspension insulator 3 respectively to protect the suspension insulator 3 in the event of a flashover.
  • a discharge electrode 9 is supported by the support 4.
  • An arresting insulator 8 is supported by the intermediate part of the support arm 2 via an adapter.
  • a discharge electrode 10 is mounted to the bottom part of the arresting insulator 8, such that it is opposite to the discharge electrode 9 with a series air gap G existing therebetween.
  • Arc horns 6A and 7A are mounted to the top and bottom end parts of the arresting insulator 8 respectively to protect the arresting insulator 8 from damage in the event of flashover.
  • the arresting insulator 8 includes a plurality of non-linear resistors 13 housed in a container 20.
  • the container 20 further includes an inner wall 11 and an outer wall 21.
  • the inner wall 11 is a cylindrical glass cloth made of fiberglass reinforced plastics impregnated with, for example, epoxy resin with carbon black.
  • the resistance of the container 20 can be controlled by adjusting the content of the carbon black in the epoxy resin of which the inner wall 11 is made.
  • the outside circumference of the inner wall 11 is provided with a plurality of pressure release holes 12.
  • a plurality of non-linear resistors 13 are housed within the inner wall 11.
  • the top and bottom ends of the inner wall 11 are sealed with end caps 14 and 15.
  • the non-linear resistors are designed to pass a large current at lightening surge voltages, but only small currents at operational voltages. Thus, they can cut off follow currents in order to prevent a ground fault in the affected line. That is, the prevent the normal operational line currents (referred to as follow currents) from being grounded (i.e. a ground fault) through the arrestor unit after the lightening surge has past.
  • the main material of the non-linear resistors 13 is zinc oxide (ZnO).
  • An upper seal 16 and a lower seal 17 are adhesively attached to the upper and lower ends of the inner wall 11 respectively by using adhesive 18.
  • a coil spring 19 is set between the end cap 15 and the lower seal 17 at the bottom part of the non-linear resistors 13 in such a way that the end cap 15 and the lower seal 17 are electrically connected with a low impedance.
  • a conductive foil shunt 100 extends between the top and bottom ends of the spring.
  • the outer wall 21 is fit airtight about the inner wall 11 and over the side walls of the upper seal 16 and the lower seal 17 by means of rubber molding.
  • a plurality of sheds 21 a are formed on the outer side of the outer wall 21.
  • the same rubber material as that of the outer wall 21 is filled into the clearance between the non-linear resistors 13 and the inner wall 11 from the pressure release holes 12 at the time of molding.
  • FIG. 3 shows the equivalent circuit of the arrestor unit in this preferred embodiment.
  • the electrostatic capacity C1 of the series air gap G, the total resistance r of the non-linear resistors 13, and the total resistance R of the container 20 are indicated. These should be set so that the discharge constant C2 * R of the container 20 is smaller than the expected time interval 7 between surges of a multiple surge lightning current. That is, R ⁇ 7 /C2 in mathematical terms.
  • the interval 7 between surges of a multiple lightning surge (i.e. the available discharge time) is in the range of 1 ms to 10ms.
  • the minimum allowable resistance Rmin is an experimentally determined resistance that is necessary to insure that the follow current will be interrupted. The experiment were based on an assumed maximum value of the allowable current of 5A (whereas the effective value is 3.5A).
  • a lightning surge (which is caused by lightning striking the power transmission line 5) flows from the support 4 and the discharge electrode 9 and flashes over to the discharge electrode 10 through the series air gap G. This begins the discharge. Then, the lightning surge flows through the lower seal 17, the non-linear resistors 13, the upper seal 16, the adaptor and the support arm 2 and is discharged to the tower 1, which is grounded.
  • the normal line current would typically try to act as a follow current (i.e. following the lightening surge to ground).
  • the resistance of the non-linear resistors 13 recovers after the lightening surge passes. Therefore, the follow current is interrupted by the recovered resistance of the non-linear resistors 13 and the serial air gap G. This prevents a ground fault in the line.
  • the arresting insulator 8 is insulated from the applied voltage side by the series air gap G, the residual charge cannot flow towards the applied voltage side.
  • the resistance R of the container 20 is set so that the discharge constant C2" R of the container 20 is smaller than the surge interval 7 . Therefore, the residual charge in the non-linear resistors 13 will drain through the container 20 within the specified time and is then discharged to the ground.
  • the arrestor unit will have a residual voltage. In this event, the voltage at the support 4 must be higher by a corresponding amount in order to reinitiate the flashover through the air gap G.
  • the voltage differential necessary to initiate a flashover through the serial air gap G is very similar to the voltage required to initiate the original flashover. Therefore, even if a multiple surge lightning current is encountered, the residual charge in the non-linear resistors 13 will be reduced sufficiently such that they appear substantially negligible.
  • the described arrestor unit has improved discharge characteristics.
  • the container 20 Since the container 20 is electrically conductive, it equally distributes the voltage between the applied voltage side and to the grounded side. Because of this characteristic, the distributed voltage can be improved when the creeping surface of the container 20 has been soiled or otherwise polluted. Thus, the creeping flashover voltage characteristic can be improved. From a different point of view, when pollution withstand voltage is considered, the arresting insulator 8 can be decreased in size and weight from the existing arresting insulators by minimizing the increase in the creeping leak distance of the container 20. Furthermore, due to the same function, the creeping flashover voltage against the discharge voltage in the event of lightning surge can be improved, and the series air gap G of the arresting insulator 8 can be shortcircuited.
  • the impedance of the arresting insulator 8 connected in series to the series air gap G is much smaller than that of the existing arresting insulators because of the fact that the container acts as a resistor R.
  • the distributed voltage of the serial air gap is much larger and the lightning flashover voltage at the initial lightning surge application is lower in comparison with existing arrestor units.
  • flashover at the arresting insulator side is easier because the flashover voltage of the arresting insulator is lower than that against lightning surge of the suspension insulator 3.
  • the impedance of the arresting insulator falls as describe above.
  • the electrostatic induction voltage caused by the operational line voltage falls, and thereby safety can be improved.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
  • Insulators (AREA)
EP19920302553 1991-03-25 1992-03-25 Unterbrechungseinheit Expired - Lifetime EP0508647B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP6049891A JPH04294083A (ja) 1991-03-25 1991-03-25 避雷碍子装置
JP60498/91 1991-03-25

Publications (3)

Publication Number Publication Date
EP0508647A2 true EP0508647A2 (de) 1992-10-14
EP0508647A3 EP0508647A3 (en) 1993-03-03
EP0508647B1 EP0508647B1 (de) 1996-10-02

Family

ID=13144027

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920302553 Expired - Lifetime EP0508647B1 (de) 1991-03-25 1992-03-25 Unterbrechungseinheit

Country Status (2)

Country Link
EP (1) EP0508647B1 (de)
JP (1) JPH04294083A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0831505A1 (de) * 1996-09-20 1998-03-25 Gec Alsthom T & D Sa Lastschalter mit variablen Dämpfungswiderstand

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106786506B (zh) * 2016-11-21 2019-08-06 国网山东省电力公司电力科学研究院 一种基于污秽物成分分析的输电线路路径选择方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859569A (en) * 1974-01-16 1975-01-07 Gen Electric Overvoltage surge arrester with improved voltage grading circuit
US3967160A (en) * 1975-05-01 1976-06-29 General Electric Company Electrical overvoltage surge arrester with a long time constant valve section and series gap section
US4270160A (en) * 1978-03-17 1981-05-26 Mitsubishi Denki Kabushiki Kaisha Lightning resistive device in aerial power transmission system
US4308566A (en) * 1979-01-11 1981-12-29 Mitsubishi Denki Kabushiki Kaisha Lightning arrester device for power transmission line
US4463405A (en) * 1981-02-19 1984-07-31 Electric Power Research Institute, Inc. Fail safe surge arrester
US4507701A (en) * 1982-07-06 1985-03-26 Mitsubishi Denki Kabushiki Kaisha Lighting arrester with leakage current detection
US4743997A (en) * 1986-12-22 1988-05-10 Carpenter Jr Roy B High-voltage systems surge eliminators for transmission lines and distribution station protection
GB2230661A (en) * 1989-02-07 1990-10-24 Bowthorpe Ind Ltd Surge arrester/diverter

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859569A (en) * 1974-01-16 1975-01-07 Gen Electric Overvoltage surge arrester with improved voltage grading circuit
US3967160A (en) * 1975-05-01 1976-06-29 General Electric Company Electrical overvoltage surge arrester with a long time constant valve section and series gap section
US4270160A (en) * 1978-03-17 1981-05-26 Mitsubishi Denki Kabushiki Kaisha Lightning resistive device in aerial power transmission system
US4308566A (en) * 1979-01-11 1981-12-29 Mitsubishi Denki Kabushiki Kaisha Lightning arrester device for power transmission line
US4463405A (en) * 1981-02-19 1984-07-31 Electric Power Research Institute, Inc. Fail safe surge arrester
US4507701A (en) * 1982-07-06 1985-03-26 Mitsubishi Denki Kabushiki Kaisha Lighting arrester with leakage current detection
US4743997A (en) * 1986-12-22 1988-05-10 Carpenter Jr Roy B High-voltage systems surge eliminators for transmission lines and distribution station protection
GB2230661A (en) * 1989-02-07 1990-10-24 Bowthorpe Ind Ltd Surge arrester/diverter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0831505A1 (de) * 1996-09-20 1998-03-25 Gec Alsthom T & D Sa Lastschalter mit variablen Dämpfungswiderstand
FR2753833A1 (fr) * 1996-09-20 1998-03-27 Gec Alsthom T & D Sa Disjoncteur de generateur avec resistance d'amortissement variable

Also Published As

Publication number Publication date
JPH04294083A (ja) 1992-10-19
EP0508647B1 (de) 1996-10-02
EP0508647A3 (en) 1993-03-03

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