JP4141231B2 - Lightning protection insulator device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning arrester device in which a lightning horn is attached in parallel with the insulator series, and more particularly to a lightning insulator device for 110-154 kV power transmission.
[0002]
[Prior art]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-93256
In order to protect a power transmission lever device from a flashover accident caused by an abnormal voltage such as lightning, a lever device in which a lever horn is attached to each of a charging side metal fitting and a ground side metal fitting is well known. The horn interval Z ₁ of these insulator series horns is set so as to achieve insulation coordination with the insulator coupling length corresponding to the voltage class. However, such a conventional arc horn does not have a function of positively interrupting the continuity associated with the flashover.
[0004]
Therefore, as shown in Patent Document 1 above, a lightning horn incorporating a ZnO element having an arrester function is attached in parallel with a conventional arc horn, and when a lightning surge voltage is received, a lightning surge current is passed through the lightning horn, A lightning protection device that cuts off the frequency continuation has already been put into practical use.
[0005]
In such a lightning arrester insulator apparatus, as current flows reliably through the arrester horn when subjected to a lightning surge voltage, the series gap length Z ₂ between lightning horn, the horn interval insulator string horn Considering insulation coordination It is set smaller than the Z _1. For this reason, there is no problem while the ZnO element is healthy. However, when the ZnO element is destroyed by lightning strike and loses its function as a lightning protection horn and becomes a conductor, the series gap length Z ₂ is smaller than the horn interval Z _1. the remaining, the operation voltage of the commercial frequency by only the series gap length Z ₂ until the lightning protection horn is repaired, it is necessary to withstand well switching surge voltage.
[0006]
In general, the switching surge withstand voltage characteristic of a transmission line is required to withstand the switching surge voltage average value + 3σ. In the lightning arrester, this requirement is satisfied if the ZnO element is normal. However, when the ZnO element breaks down, it is difficult to satisfy this requirement only with the series gap length Z ₂ set in consideration of the insulation coordination with the horn interval Z ₁ of the insulator series. Therefore, the switching surge withstand voltage at the time of ZnO element breakdown failure is set to about the average value + 2σ from the viewpoint that the occurrence probability of the switching surge voltage average value + 3σ and the overlapping probability of the breakdown failure of the ZnO element are very small. When the general value of the resistance reactor grounding method in which the average value μ of the switching surge voltage is 2.25 times and the standard deviation σ is 0.35 times is adopted, μ + 2σ = 2.95 times, and 154 KV × (1 .15 / 1.1) × (√2 / √3) × 2.95 times × 1.1 From the general formula for the withstand voltage, even if a switching surge voltage of 427 KV is received, the series gap length Z ₂ is not discharged. It is necessary to.
[0007]
In order to meet this requirement, the series gap length Z ₂ may be sufficiently increased. However, increasing the series gap length Z ₂ is contrary to the original purpose of surely passing a current through a lightning protection horn when receiving a lightning surge voltage. In particular, since the insulation design of the existing transmission line of 154 KV is in harsh conditions compared to other voltage classes, the switching surge voltage at the time of ZnO element breakdown failure has been set to μ + 1σ in the operation examples of the lightning arrester so far. . Since it is not easy to simultaneously satisfy the contradictory requirements as described above, it has not been realized so far to apply the structure shown in Japanese Patent Laid-Open No. 2002-93256 to a voltage class such as 154 kV.
[0008]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems, can reliably pass a lightning surge current through a lightning protection horn when receiving a lightning surge voltage, and average value even in the case of a failure in which a ZnO element is destroyed by a lightning strike. It was made to provide a lightning arrester that can have switching surge voltage characteristics that can withstand + 2σ.
[0009]
[Means for Solving the Problems]
As a result of repeated studies by the present inventors to solve the above-mentioned problems, paying attention to the characteristic difference between the lightning impulse and the switching surge impulse, and devising the shape of the series gap electrode provided at the tip of the lightning horn, It was clarified that a design that satisfies the contradicting demands of the system could be made at the same time.
[0010]
The present invention has been made based on this finding, and a lightning protection horn provided with a series gap electrode at the tip of a ZnO element at one end of each of a charging side metal fitting and a ground side metal fitting of an insulator series for 110-154 kV power transmission. with the attaching to have a series gap length Z _2, in lightning protection insulator attached to the respective other ends to have a distance Z ₁ to a suitable insulator string horn insulation coordination, spherical series gap electrodes of voltage application side an electrode, and a series gap electrodes on the ground side and the rod-shaped electrode, and the diameter of the spherical electrode, a 2-4 times the diameter of curvature of the tip of the rod-shaped electrode on the ground side, and the series gap length Z ₂ 5 to 12 % Range .
[0011]
Incidentally, in order to improve the insulation coordination property, it is preferable that the series gap length Z ₂ and less than 60% of the horn interval Z _1.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a 154 kV power transmission insulator series, wherein 1 is an insulator series, 2 is a ground metal fitting for fixing the insulator series 1 to a steel tower arm, and 3 is an insulator series 1. It is the electric power transmission side metal fitting for attaching a power transmission line to the lower end of this. The lightning protection lever device of the present invention can also be applied to 110 kV power transmission.
[0013]
A lightning protection horn 5 is attached to one end of the grounding side metal fitting 2 via a horn attachment metal fitting 4, and an insulator series horn 6 is attached to the other end. A lightning protection horn 8 is attached to one end of the power-applying side fitting 3 via a horn attachment fitting 7, and an insulator reaming horn 9 is attached to the other end. The insulator series horn 6 and the insulator series horn 9 are opposed to each other with an interval Z ₁ suitable for insulation coordination in the voltage class as in the conventional case. In the case of 154 kV, the standard insulation interval 1300 mm, the horn gap The conversion value at is 1208 mm.
[0014]
Both the lightning protection horns 5 and 8 are provided with series gap electrodes 10 and 11 at the tips of ZnO elements, and the outer periphery of the main body is completely covered with an insulating coating 12. In addition, L-shaped arc guides 13 and 13 are provided on both sides of the lightning protection horns 5 and 8, and when an excessive lightning surge is received, the arc guides 13 and 13 are discharged to prevent the ZnO element from being destroyed. When the main body is released due to a ground fault or short-circuit current in the event of destruction of the ZnO element, the arc current is instantaneously transferred between the arc guides 13 and 13 to reduce arc damage of the main body and prevent explosion explosion. ing.
[0015]
The lightning arrester device of the present invention is characterized in that the series gap electrode 11 of the lightning arrester horn 8 on the charging side is a spherical electrode having excellent electric field relaxation characteristics, and the series gap electrode 10 of the lightning arrester horn 5 on the ground side is a rod electrode. There is. A series gap length Z ₂ is formed between the series gap electrodes 10 and 11. The reason why the charging side is a spherical electrode and the ground side is a rod-like electrode is as follows.
[0016]
Although lightning impulse flashover voltage is affected by the series gap length Z _2, it is known to hardly affected by the electrode shape. Therefore, the lightning impulse flashing voltage is almost the same even when the power application side is a spherical electrode and the ground side is a rod-shaped electrode as in the present invention, and both are rod-shaped electrodes as in the prior art. However, the switching surge impulse is easily affected by the electrode shape, and the switching surge withstand voltage can be greatly improved by reducing the electric field by using the series gap electrode 12 on the charging side as a spherical electrode. For this reason, if the charging side is a spherical electrode and the ground side is a rod-like electrode, only the switching surge withstand voltage can be improved without affecting the lightning impulse flashover voltage characteristics.
[0017]
As a result of experiments conducted on the electrode shape by the present inventor, as the diameter of the spherical electrode increases, the electric field relaxation characteristics improve. On the other hand, when water droplets or the like adhere to the surface, local electric field concentration occurs in the portion, and the electric field It was found that the relaxation effect is easily impaired. In addition, since Z ₁ and Z ₂ cannot be changed greatly in an actual lightning arrester, the diameter of the spherical electrode is naturally limited. Therefore, there is an optimal range for the diameter of the spherical electrode, confirming that the range of 5 to 12% of the series gap length Z2 is _{2 to} 4 times the curvature diameter of the tip of the rod electrode on the ground side. did.
[0018]
The graph of FIG. 2 measures the switching surge withstand voltage when the curvature diameter of the tip of the rod-like electrode on the ground side is a constant value of 19 mm and the diameter of the spherical electrode on the charging side is changed between 20 and 100 mm. It is the result. It has been shown that μ + 1.5σ can be cleared in the range of 38 to 76 mm corresponding to 2 to 4 times the curvature diameter of the tip of the rod-shaped electrode, and the characteristics can be improved compared to the rod-shaped electrode. It is considered that when the diameter of the spherical electrode is small, the electric field relaxation effect is lowered, and even if it is too large, the electric field relaxation effect is impaired when water droplets or the like adhere to the surface.
[0019]
The graph of FIG. 3 shows the relationship between the series gap length Z ₂ and the switching surge withstand voltage. As shown in this graph, the conventional product with both rod-shaped electrodes conventionally requires a series gap length Z ₂ of 730 mm in order to clear μ + 2σ, but as in the present invention. If the electric side is a spherical electrode, μ + 2σ can be cleared even if the series gap length Z ₂ is 700 mm. According to the present invention, it is possible to shorter than conventional series gap length Z ₂ while maintaining the required switching surge withstand voltage, through lightning horn more reliably lightning surge current when subjected to a lightning surge voltage It can flow. In addition, the whole insulator device can be made compact.
[0020]
The preferable diameter of the above-mentioned spherical electrode on the charging side corresponds to approximately 5 to 12% of this series gap length Z ₂ = 700 mm. For this reason a 2-4 times the diameter of curvature of the tip of the rod-shaped electrode on the ground side diameter of the spherical electrode as noted in claim 2, and a 5 to 12% of the range of the series gap length Z ₂ It was preferable to do.
[0021]
Further, as described above, the insulator horn 6 and the insulator horn 9 are opposed to each other with an interval Z ₁ = 1300 mm suitable for insulation coordination in the case of 154 kV. From the viewpoint of insulation coordination characteristics, the series gap length Z ₂ is preferably 60% or less of the horn interval Z ₁ , and when the series gap length Z ₂ = 700 mm, Z ₂ / Z ₁ = 0.54.
[0022]
When the curvature diameter of the tip of the rod-shaped electrode is 19 mm, the diameter of the spherical electrode on the charging side is 50 mm, and the series gap length Z ₂ is 700 mm, the insulation coordination characteristics are set to a standard insulation interval of 1300 mm when using a statistical method. On the other hand, it was 1.89σ (cooperation failure probability 2.94%), 3.46σ (cooperation failure probability 0.03%) with respect to the insulator horn interval 1300mm, and it was confirmed that it can be applied to transmission lines without cooperation failure. It was.
[0023]
【The invention's effect】
As described above, the lightning arrester of the present invention pays attention to the characteristic difference between the lightning impulse and the switching surge impulse, and the series gap electrode on the charging side is a spherical electrode, and the series gap electrode on the ground side is a rod electrode. It is a thing. As a result, the lightning arrester device of the present invention can surely flow the lightning surge current through the lightning horn when the lightning surge voltage is received and interrupt the continuity, and even in the event of a failure where the ZnO element is destroyed by lightning strike. The switching surge voltage characteristics can withstand the average value + 2σ. Furthermore, there is no problem in terms of the insulation coordination characteristics, and there are many advantages such that the overall series gap length Z ₂ can be shortened to contribute to the overall size reduction.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment T lightning according to the present invention.
FIG. 2 is a graph showing the relationship between the diameter of a spherical electrode on the charging side and the switching surge withstand voltage.
FIG. 3 is a graph showing the relationship between series gap length Z ₂ and switching surge withstand voltage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 insulator series, 2 grounding side metal fittings, 3 electrical charging side metal fittings, 4 horn mounting metal fittings, 5 lightning horns, 6 insulator reaming horns, 7 horn mounting metal fittings, 8 lightning protection horns, 9 insulator reaming horns, 10 series gap electrodes, 11 series Gap electrode, 12 insulation coating, 13 arc guide

Claims (2)

A lightning horn provided with a series gap electrode at the tip of a ZnO element is attached to one end of each of the insulator-side charging side metal fitting and grounding side metal fitting for 110-154 kV power transmission with a series gap length Z ₂ , respectively. In the lightning insulator in which the insulator horn is attached to the other end of the insulator with a gap Z ₁ suitable for insulation coordination, the series gap electrode on the charging side is a spherical electrode, the series gap electrode on the ground side is a rod electrode, and the diameter of the spherical electrodes are 2-4 times the diameter of curvature of the tip of the rod-shaped electrode on the ground side, and lightning arrester insulator apparatus, characterized in that the 5 to 12% of the series gap length Z _2. Series gap length Z ₂ Horn interval Z ₁ The lightning protection insulator device according to claim 1, which is 60% or less.

Images