JP3835940B2 - Lightning intrusion protection device in low voltage distribution system. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning intrusion protection device that is installed in a low-voltage distribution line and is used as a protective measure against insulation breakdown or burning accident caused by a lightning surge.
[0002]
[Prior art]
The damage caused by lightning surges on high-voltage distribution lines in the distribution system has decreased rapidly with the spread of lightning arresters with built-in zinc oxide elements, except for instantaneous power outages due to substation trips caused by discharge clamp flashovers.
The lightning arrester installed in this high-voltage distribution line operates when the generated lightning surge voltage exceeds a certain value, and distributes the lightning surge current through the neutral line (ground phase) and discharges it to the ground. Protects electric wires and various power distribution devices.
[0003]
On the other hand, on the end customer side branched from high-voltage distribution lines via pole transformers and low-voltage distribution lines, various office automation equipment, electrical appliances, electrical devices, etc. are spreading and high density due to advanced information technology. Although the importance of these increases with the implementation, the risk of exposure to lightning surges via communication lines and antennas tends to increase.
Therefore, in order to protect the consumer side load from the invasion of lightning surges, various societies and organizations are examining and planning various measures.
[0004]
As one of them, a countermeasure plan called “bypass arrester” method as shown in FIG. 4 is jointly proposed mainly by a telecommunications company and a power company.
In this method, a lightning arrester 56 is installed at a predetermined location in a range including the communication line 58 from the neutral line (grounding phase) of the lead-in line 55 of the customer 59, and a common grounding line 57 is provided to bypass the lightning surge. By connecting the common ground line 57 and the neutral line (ground phase) of the pole transformer 53 and the low voltage distribution line 54, one system for discharging the lightning surge current to the ground is constructed. Based on this system, a proposal for further improvement and development was born, and some practical tests have been conducted. In addition, 51 is a high voltage distribution line, 52 is a high voltage lightning arrester.
Improvements and developments of the “Bypass Arrester” method described above are in widespread use, especially in Germany, and are also being considered for use as a recommendation by electric power companies in Japan.
[0005]
[Problems to be solved by the invention]
However, when the above-mentioned “bypass arrester method” is widely implemented on the consumer side, due to the difference between the ground impedance of the common ground line 57 on the consumer side and the ground impedance of the class B ground of the pole transformer 53, A phenomenon in which lightning surge current flows backward from the customer 59 side to the neutral line (ground phase) side of the low-voltage distribution line 54 is likely to occur.
[0006]
That is, as shown in FIG. 5, the common ground line 57 on the customer 59 side is house ground, and thus has to have a relatively high impedance. Lightning surge current flows to the device 53 side. At that time, in the low-voltage distribution line 54 installed on the utility pole 60 such as a concrete pole, the utility pole 60 has a low grounding impedance, so a flashover occurs from the low-voltage retaining insulator 61 to the utility pole 60, resulting in an insulation breakdown or a burnout accident. There is a risk of causing. Further, these phenomena have a risk of developing into a multiphase flashover and causing a short circuit between phases.
[0007]
In other words, in the “bypass arrester method”, as a result of installing protective devices such as lightning arresters to suppress lightning surges on the high-voltage distribution line and the customer side, the low-voltage distribution line between the high-voltage distribution line and the consumer is lightning from both sides. It becomes easy to be affected by the surge and exposed as the weakest point.
Also, grounding work for optimizing the ground impedance of the common ground line on the customer side is extremely difficult because the number of customers and the form of each house are different.
[0008]
Therefore, the present invention adds a relatively simple configuration to the low voltage distribution line that can be said to be the weakest point of lightning surge current in the high voltage distribution line, pole transformer, and low voltage distribution system from the low voltage distribution line to the customer via the lead-in line. By doing so, it is intended to provide a lightning intrusion protection device with an enhanced protection function for the low voltage distribution system.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the invention described in claim 1, a low-voltage distribution line is branched from a pole transformer connected to a high-voltage distribution line, and electric power is supplied from the low-voltage distribution line to a consumer via a lead-in line. In addition, the lead-in wire neutral wire connected to the neutral wire of the low-voltage distribution line grounded on the pole transformer side and the communication wire connected to the customer are connected to the common ground wire via the lightning arrester. In the low-voltage distribution system, a lightning surge protection element for discharging lightning surge current to the ground is connected between the potential line of the low-voltage distribution line installed on the utility pole, the neutral line, and the utility pole ground line. is there.
[0010]
In the invention according to claim 2, the low-voltage distribution line is branched from the pole transformer connected to the high-voltage distribution line, and electric power is supplied from the low-voltage distribution line to the consumer via the lead-in line. In the low-voltage distribution system in which the lead-in wire neutral wire connected to the low-voltage distribution wire neutral wire grounded on the transformer side and the communication wire connected to the customer are connected to the common ground wire via a lightning arrester Between the potential line of the low-voltage distribution line installed on the utility pole, the neutral line, and the utility pole ground line, the potential line, the neutral line, and the utility pole ground line are connected to each other so that a gap is held between them. An arc current limiting means having an electrode and an arc extinguishing chamber surrounding these electrodes is provided.
[0011]
In addition, as described in claim 3, it is desirable that the lightning surge protection element according to claim 1 or the arc current limiting means according to claim 2 be collectively stored in a housing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 shows a use state of an embodiment of the present invention, which is a case where a lightning intrusion protection device 10 according to the present invention is applied to a 100/200 V single-phase three-wire overhead low voltage distribution system. Here, the present invention can also be applied to various low-voltage distribution systems of 200V three-phase three-wire system.
[0013]
This lightning intrusion protection device 10 is connected to a potential pole (voltage phase) 54a, 54b of a low-voltage distribution line 54 installed on a utility pole 60 such as a concrete pole via a low-voltage retaining insulator 61, and a utility pole ground line 62. A neutral wire (ground phase) 54c is connected via an insulated cable 14.
Examples of the lightning intrusion protection device 10 include an example using a discharge action of a lightning surge current by a lightning surge protection element as shown in FIG. 2, and an example using an arc current limiting action as shown in FIG.
[0014]
First, the lightning intrusion protection device 10A shown in FIG. 2 is connected to the potential lines (voltage phase) 54a, 54b, the neutral line (ground phase) 54c, and the utility pole ground line 62 via the insulated cable 14. The surge protection elements 11 and 12 are collectively housed in the housing 16.
These protective elements 11 and 12 are composed of a combination of a ceramic containing zinc oxide (ZnO) as a composite component, a zinc oxide element, and a lightning arrester. 11 and 12 may be integrally formed of an insulating resin having excellent weather resistance.
[0015]
As the operation, when a lightning surge enters the low-voltage distribution line 54 during a lightning strike and the potentials of the potential lines 54a and 54b rise to a predetermined value, the lightning surge protection elements 11 and 12 are operated to ground the lightning surge current to the utility pole. Release from line 62 to ground.
As a result, there is no risk of flashover occurring on the utility pole from the potential lines 54a and 54b via the low-voltage retaining insulator as in the prior art, and it is possible to prevent the occurrence of dielectric breakdown or burnout accidents.
[0016]
Next, the lightning intrusion protection device 10B shown in FIG. 3 utilizes an arc current limiting action, and is connected to the potential lines 54a and 54b and the neutral line 54c connected to the utility pole ground line 62, respectively. Insulating cables 14 a, 14 b, 14 c that penetrate 16, and the needle electrodes 15 formed at the tips of these insulating cables 14 a, 14 b, 14 c are the same in the arc extinguishing chamber 17 inside the housing 16 via the gap 18. Oppositely arranged on a plane.
The casing 16 is formed of a resin such as polyacetal, and generates an inert gas by heat when an arc is generated between the needle electrodes 15.
In the above configuration, the needle electrode 15, the casing 16, the arc extinguishing chamber 17, the gap 18 and the like constitute the arc current limiting means in claim 2.
[0017]
When a lightning surge is generated in the low-voltage distribution line 54, a flashover and an arc are generated between the needle-like electrodes 15 of the neutral wire 54c connected to the potential lines 54a and 54b or the utility pole grounding wire 62, and the potential due to the lightning surge is generated. Suppresses the rise. Thereafter, the tip of the needle-like electrode 15 is melted instantaneously by the heat of the arc, and the length of the gap 18 is increased, resulting in an increase in arc resistance, and further generation of inert gas from the housing 16, The arc continuity is interrupted.
[0018]
Although not shown in the figure, a thin weak portion is provided in a part of the housing 16 and the weak portion is destroyed when the gas in the arc extinguishing chamber 17 is heated to a high pressure. Thus, the internal pressure of the arc extinguishing chamber 17 is released at once. The strong air flow accompanying this pressure release further promotes the arc extinguishing action, and the arc continuity is reliably interrupted.
[0019]
For this reason, at the time of lightning surge intrusion, the potential rise of the potential lines 54a and 54b is suppressed to a certain value or less due to the occurrence of an arc, and thereafter the arc continuity is interrupted.
Moreover, in this embodiment, it is possible to set the lightning surge voltage which should be suppressed to arbitrary values by adjusting the length of the gap 18 between the acicular electrodes 15.
[0020]
Further, in any of the examples of FIGS. 2 and 3, the lightning surge protection elements 11 and 12 and the needle-like electrode 15 and the like are collectively housed in the housing 16, and the whole is integrally formed and insulated. Since the structure is such that the cable 14 or 14a to 14c is pulled out and connected to the low-voltage distribution line, the construction can be performed safely and easily even on a power pole with a poor footing.
[0021]
【The invention's effect】
As described above, according to the present invention, by installing a lightning intrusion protection device that is extremely simple in structure and easy to connect to the utility pole erection part of the low-voltage distribution line that can be said to be the weakest point at the time of lightning surge intrusion, While protecting the load of low-voltage customers, which are increasing in importance, it stabilizes the lightning intrusion protection performance of the entire distribution system and improves the reliability.
[Brief description of the drawings]
FIG. 1 is a diagram showing a use state of an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of the lightning intrusion protection device in FIG. 1;
FIG. 3 is a schematic configuration diagram of the lightning intrusion protection device in FIG. 1;
FIG. 4 is an explanatory diagram of a bypass arrester method as a prior art.
FIG. 5 is an explanatory diagram of problems of the bypass arrester method.
[Explanation of symbols]
10, 10A, 10B Lightning intrusion protection device 11, 12 Lightning surge protection element 14, 14a, 14b, 14c Insulated cable 15 Needle electrode 16 Housing 17 Arc extinguishing chamber 18 Gap 54 Low voltage distribution line 54a, 54b Potential line (voltage phase )
54c Neutral wire (ground phase)
60 Telephone pole 61 Low voltage retaining insulator 62 Telephone pole ground wire

Claims (3)

The low-voltage distribution line is branched from the pole transformer connected to the high-voltage distribution line, and power is supplied from the low-voltage distribution line to the customer via the service line, and the low-voltage distribution line grounded on the pole transformer side. In the low-voltage distribution system in which the lead-in wire neutral wire connected to the wire neutral wire and the communication wire connected to the customer are connected to the common ground wire via a lightning arrester ,
A low-voltage distribution system characterized by connecting a lightning surge protection element to discharge lightning surge current to the ground between the potential line of the low-voltage distribution line installed on the utility pole, the neutral line, and the utility pole ground line Lightning intrusion protection device. The low-voltage distribution line is branched from the pole transformer connected to the high-voltage distribution line, and power is supplied from the low-voltage distribution line to the customer via the service line, and the low-voltage distribution line grounded on the pole transformer side. In the low-voltage distribution system in which the lead-in wire neutral wire connected to the wire neutral wire and the communication wire connected to the customer are connected to the common ground wire via a lightning arrester ,
An electrode connected between the potential line of the low-voltage distribution line installed on the utility pole , the neutral line, and the utility pole grounding line, and connected to these potential line, neutral line, and utility pole grounding line, and having a gap between them. And a lightning intrusion protection device in a low-voltage distribution system, characterized in that an arc current limiting means having an arc extinguishing chamber surrounding these electrodes is provided.   A lightning intrusion protection device in a low-voltage power distribution system, wherein the lightning surge protection element according to claim 1 or the arc current limiting means according to claim 2 is collectively stored in a housing.

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