JPH0716537U - Transmission line tower lightning arrester - Google Patents

Abstract

(57) [Summary] [Purpose] During a lightning strike on a transmission line, a reverse flashover accident on the power line caused by a rise in the potential of the tower due to a direct current lightning current on the span or the tower caused by the intrusion of the lightning current into the tower In order to eliminate it, the steel tower with high surge impedance characteristics should be made non-conductive. [Structure] An insulator 7 is interposed between an overhead ground wire 1 and a steel tower 3, and the ground wire 1 is electrically insulated and held at the top of the tower. A closed circuit including a series of conductors and ground is formed by pulling it down through the support insulator 9 in an isolated state, joining it to the ground wire 5 and the steel tower 3 at the grounding point 5a of the tower leg, and grounding them. A steel tower lightning arrester.

Description

[Detailed description of the device] [Industrial applications]

 The present invention relates to a method of grounding an overhead ground wire installed on a steel tower, and relates to a lightning protection device for a steel tower of a transmission line.

[Prior art]

 Conventionally, with regard to lightning protection of transmission lines, an overhead ground wire for lightning strike prevention, that is, lightning shielding is installed at the top of the line, and this overhead ground wire is installed at the top of each steel tower grounded by the tower legs. By connecting and directing the electric charge of lightning to the ground through the steel tower, it was expected to shield lightning from power lines and to prevent lightning. However, when a lightning current flows into the tower, the resistance of the tower raises the electric potential of the tower, causing a potential difference with the power line.If this exceeds the dielectric strength of the insulator device of the power line, a reverse flashover from the tower to the power line occurs. To do. For this reason, it has been possible to reduce the ground resistance of the tower by multiple grounding, bridging, high insulation, unbalanced insulation method, multiple grounding, or avoiding lightning accidents due to direct lightning surges on power lines. Therefore, various measures were taken, such as installing a lightning arrester for the track at the end of the steel tower arm, but the current situation is that the electrical accidents caused by lightning have not been eliminated yet.

[Problems to be solved by the device]

 This is because the conductor configuration from the overhead ground wire to the buried ground wire via the steel tower is a point or surface connection using ground wire clamps, connecting fittings, steel tower materials, terminals, bolts, etc. This is because the reflection phenomenon due to a steep lightning wave occurs and the lightning current does not propagate smoothly to the buried ground line at the end.The electric potential of the steel tower rises by passing the lightning current directly to the steel tower with high surge impedance characteristics. This has caused a reverse flashover accident on the power line. In order to solve this problem, Japanese Utility Model Publication No. 12-7011 (Draft I) proposes a Y-type grounding conductor that hangs on an overhead ground wire that is erected and insulated from a steel tower and is electrically isolated from the steel tower. An "overhead ground wire device" in which the above is connected to a ground plate independent of the steel tower is disclosed, and Japanese Patent Application Laid-Open No. 54-119693 (proposal II) discloses that an overhead ground wire insulated from the steel tower is installed on a coaxial cable. A "lightning arrester for overhead power line" is disclosed in which the core wire is connected, the lower end is grounded, and the exterior is also grounded at the lower end. An overhead ground wire that is erected with insulation is installed as it is along the outside of the main pillar material of the steel tower, and it is vertically laid with insulation, and the lower end is connected to the buried ground wire and the steel tower at the tower leg. A "lightning protection method for power transmission lines" is disclosed. However, with plan I, it is connected to an independent ground plate (higher ground resistance than the tower), the overhead ground wire and the drooping ground conductor are connected at an acute angle, and there are many connection points. In addition, there is a risk of a reverse flash from the ground conductor to the steel tower or power line due to the reflection phenomenon caused by a steep lightning wave. However, it has not been put to practical use because there is a problem that hinders its application. Regarding Plan II, when a lightning strike wave having an extremely high frequency characteristic flows through the coaxial cable, the current does not flow to the core wire due to the skin effect, but flows through the exterior part. Since the lightning surge is also shunted to the steel tower body and the potential rise of the steel tower may cause reverse flashover to the power line, it has not been put to practical use. Regarding the proposal III, in 1993, IEEJ Paper No. 1281 “Control of tower flashover by lightning protection line” (Central Research Institute of Electric Power Industry) describes the technical and technical effects (the number of hanging lines and the placement position) of the proposed lightning protection concept. Although it was proved by C, E, and G, the installation position of the hanging line, which is the scope of the claim, is installed along the outside of the main pillar, so when applying it to the actual line, Installation of the existing transmission line is dangerous because it hinders the ascent and descent to the tower, and a power failure is required. When using the optical fiber composite overhead ground wire (OPGW) In addition to arranging the inside of the building, there was a problem that there was concern that the contact person might be hindered by the electromagnetic induction voltage induced when the connection with the buried ground wire was poor.

[Means for Solving the Problems]

 This invention was made in order to solve the problems of the above-mentioned plan III and to make it practical, and it is possible for a person to attach the hanging line 4 arranged along the outside of the main pillar 3a from the tower top. By hanging along the inside of the tower main body (the center or the inside of the belly member 3b) that is not easily touched and does not easily hit objects, and is separated from the tower body by the support insulator 9. In addition to supporting the construction method inside the tower in the case of OPGW construction, it also prevents the occurrence of personal injury, etc. With this improvement, the effect of reducing the voltage generated between insulators, which is the purpose of Plan III, is described in the demonstration experiment case. As shown in H to K, there is almost no change.

[Action]

 In this manner, the overhead ground wire 1 spans the steel towers 3 while being insulated from the steel towers 3, and the both ends of the overhead ground wires 1 are insulated from the steel towers 3 and are provided along the inside of the steel towers 3. Each of the terminals is connected to the buried ground wire 5 and the tower body at the grounding point 5a of the tower leg of the steel tower 3 via the, and each overhead ground wire 1 and the adjacent overhead ground wire 1 are connected to the top of the tower. By connecting the jumper wire 6 which is isolated and bridged at, the total surge impedance of the conductive circuit from the overhead ground wire 1 to the ground is reduced, and the electrostatic capacitance between the down wire 4 and the steel tower 3 is reduced. To mitigate the lightning strike surge and guide the lightning current from the overhead ground wire 1 to the buried ground wire 5 via the hanging wire 4 to the ground without interposing the steel tower 3 of high surge impedance. It suppresses the rise in the electric potential of the steel tower. Further, since it is connected to the steel tower 3 at the hanging wire 4 disposed inside the tower and the grounding point 5a of the tower leg, the descending current of the hanging wire 4 to the grounding point 5a and the grounding point 5a to the steel tower 3 are connected. The rising directions of the reflected currents are opposite to each other, and the two cancel each other out, so that the potential increase of each of the hanging line 4 and the steel tower 3 is suppressed, so that the hanging wire 4 to the steel tower 3 or the steel tower 3 to the power line 2 is suppressed. Reverse flashover can be prevented.

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows that the overhead ground wire 1 retained by the retractor insulator device attached to the top of the steel tower is pulled down while the inside of the steel tower 3 is insulated by the support insulator 9, and its end is grounded to the ground point 5a of the tower leg. In the situation diagram in which the buried ground wire 5 and the steel tower 3 are connected with each other, in the same figure A, the hanging wire 4 is drawn down inside the belly member 3b, and in the same drawing B, the hanging wire 4 is drawn down at the center of the tower body. Fig. 2 is a layout diagram of the case, and Fig. 2 shows a conduction circuit in which the hanging wire 4 and the buried ground wire 5 in both towers connected to the overhead ground wire 1 installed in the span are integrally and continuously connected. There is. This conduction circuit is constructed under the following conditions. 1. The overhead ground wire 1 is a predetermined electric wire, for example, a steel core No. a aluminum alloy twisted wire, an aluminum twisted twisted wire, or an optical fiber composite overhead ground wire (OPGW). 2. The detention clamp 8 of the overhead ground wire 1 is a metal object having a shape capable of gently bending and gripping the ground wire. (Fig. 3) In case of OPGW, use a special tension clamp. 3. The retention insulator 7 is a 180 mmφ suspension insulator. (Fig. 3) 4. The jumper wire 6 at the top of the tower and the hanging wire 4 for pulling down the inside of the tower body are held by a support insulator 9. (FIGS. 3 and 4) 5. The insulator standard is a nominal voltage, 6.6 Kv, 50% shock flashover characteristic voltage, 70 Kv or more. 6. The hanging line 1 and the steel tower member 3b are separated by about 15 cm. Therefore, the support insulator is fixed to the member by using a cleat, a holder 10 and the like. (Fig. 5) 7. The impulse ground resistance value (wave electric resistance) of the buried ground wire 5 should be lower than the impulse ground resistance value (100Ω) of the steel tower. 8. The terminal of the hanging wire 4 and the buried ground wire 5 connected to the grounding point 5a of the tower leg is subjected to compression terminal treatment, and is fastened to the steel tower member with bolts. 9. The supporting wire 9 is used to hold and stretch the hanging wire 4 so that the hanging wire 4 arranged in the tower does not relax. 10. In constructing the overhead ground wire 1, after extending the overhead wire section all at once, pull down the hanging wire 4 (Article 2) provided in the tower for each tower, and then draw the overhead ground wire 1 at the top of the tower. Fastening, connecting the jumper wire 6 and arranging the hanging wire 4 in the tower. Although the above description is for the case where the number of overhead ground wires in the span is one, even when the number of overhead ground wires is two, the same hanging line is used for each overhead ground wire in the tower. It should be installed. When constructing the OPGW, pull down the OPGW only for the steel tower where the optical junction box (JB) is installed because it is installed inside the tower, and connect the terminal to the buried ground wire and the steel tower and ground it. As for the steel tower where J / B is not installed, the OPGW between the two diameters is supported by the support insulator 9 at the top of the tower and is continuously erected in an insulated state. Separately, a hanging wire that connects the OPGW at the top of the tower and the grounding point 5a at the tower leg is insulated by a support insulator and placed inside the tower to form a conductive circuit similar to an overhead ground wire.

[Effects of the Invention] As described above, with the tower lightning arrester according to the present invention, the tower potential rise due to the lightning surge that could not be prevented by the lightning protection measures carried out based on the conventional anti-lightning design (flowing a lightning current to the tower), In addition to significantly reducing the reverse flashover accidents and power system transmission accidents to the power lines that accompany this, various problems that hindered the practical implementation of the plan III (caused by obstacles during ascent / descent and guidance) It is a highly effective measure that contributes to the further stabilization of the power supply and the maintenance and management of the equipment. The effect is great.

[Brief description of drawings]

1 is an explanatory view showing an embodiment of the present invention, in which FIG.
If the hanging line is pulled down inside the belly member of the tower,
[Fig. 4] is a side view and a cross-sectional view of the tower body when the central portion of the plumbing tower body is pulled down.

FIG. 2 is an explanatory view showing a conduction circuit of a lightning arrester formed by joining an overhead ground wire, a hanging wire, and a buried ground wire that are installed in a span at a grounding point of a tower leg.

FIG. 3 is an enlarged front view of a detention clamp section at the top of the tower of FIG.

FIG. 4 is an enlarged front view of the support portion of the tower hanging line (inside of the abdominal material) of FIG. 1A.

FIG. 5 is an enlarged plan view of a support portion of the in- tower hanging line (center portion) of FIG. 1B.

[Explanation of symbols]

 1 Overhead ground line (or OPGW) 2 Power line 3 Steel tower 3a Steel tower member (main pillar material) 3b Steel tower member (belly material, diagonal material, opposite side material, etc.) 4 Pendant line 5 Buried ground wire 5a Ground point (steel tower of buried ground wire) Connection point) 6 Jumper wire 7 Insulator for suspension (suspending insulator) 8 Straining clamp (or tension clamp for OPGW) 9 Support insulator 10 Holder (or cleat)

Claims (5)

[Scope of utility model registration request] 1. A single hanging line, which is continuously formed integrally with the overhead ground wire, is provided on both ends of the overhead ground wire that is installed on the steel tower of the transmission line while being insulated from the steel tower. It is insulated from the steel tower and hung vertically through the inside of the steel tower body. 2. An end portion of each of the vertically extending hanging lines is connected and grounded at the grounding point joined to the buried ground wire and the steel tower at the steel tower tower leg portion. 3. A jumper wire for electrically bridging overhead ground wires between two adjacent diameters at the top of a steel tower is insulated from the steel tower by a support insulator. 4. When the OPGW is used for the overhead ground wire and the wiring in the tower is not performed, the OPGW between the two diameters is insulated and connected to the steel tower by a support insulator at the top of the tower, and the OPGW is separately provided.
The hanging wire connecting the GW and the grounding point is insulated with a support insulator and placed inside the tower. 5. A series of lightning conductors, in which the above-mentioned overhead ground wire, drooping wire, jumper wire, and buried ground wire are connected, and a conductive closed circuit including the ground are formed for each span, and a steel tower is connected to this. The steel tower lightning arrester is characterized in that the lightning conductor and the steel tower become electrically the same electric potential by being joined at a point, and the steel tower serves as a branch path in a circuit manner.