JP2892870B2 - Building grounding automatic switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lightning arrester in an intelligent building, a computer center, an industrial facility, or the like, in which a lightning rod, a power protection ground, and a weak power / signal ground are provided independently. In addition, the present invention relates to a building grounding type automatic switch for preventing damage to equipment with weak insulation when variations in the potential rise of each grounding electrode occur.

[0002]

2. Description of the Related Art Electrical grounds can be broadly classified into two categories: power-related security grounds, and signal potential stabilized grounds used in telecommunications and computer control.

At present, it is difficult to obtain a large business site,
In order to obtain a low grounding resistance, mesh grounding, parallel grounding, etc. are necessary. In case of lightning, if all grounding is shared, the entire office will be at the same potential and damage will be minimized. For this reason, a so-called common grounding method in which all the grounds are commonly used has become mainstream.

[0004] However, in the case of precision electric equipment mainly for computer control, there is a strong demand for eliminating noise interference, and there are many demands for a single grounding system, and in many cases, an independent single grounding facility is provided.

[0005] In normal times, such a single grounding method is ideal. However, once lightning strikes occur, a potential difference is generated between the grounding poles, and in many cases, weak electrical equipment having low withstand voltage performance is damaged. This kind of accident is behind.

Therefore, as a countermeasure, a building grounding system in which a surge arrester such as a surge absorber is installed between each grounding pole is desired. However, when the lightning strikes on the lightning rod and the local voltage on the floor of the building rises with respect to the ground, the energy absorption performance of the surge absorber is insufficient, so that the above lightning arrester may be burned and useless.

In order to improve the energy resistance performance, an arrester having a "discharge gap" may be used.
In ordinary `` lightning arresters for electric circuit '', the discharge current by the commercial power supply after discharging, the electrode material is limited to prevent the so-called `` continuous current '', the gap can not be limited more than a certain degree, For example, a spark electrode made of carbon, which has a high heat resistance and no melting property, so that the gap can be extremely narrowed, cannot be used because the follow current blocking performance is extremely poor. Therefore, there still remains a problem that the discharge starting voltage of the discharge gap cannot be lowered and coordination with the dielectric breakdown voltage of the electric circuit cannot be achieved.

[0008]

As described above, in the conventional method, the following methods are required. In the case of the independent grounding method, when any one of the grounding electrodes rises in potential, the influence may be greatly affected by the weak electric equipment.

[0009] 2. When the common grounding method is adopted, the above-mentioned 1. Can prevent the damage, but it cannot provide enough processing for noise disturbance in normal times.

[0010] 3. In a grounding system in which a surge absorber or a conventional surge arrester in which a discharge gap is connected in parallel with a surge absorber is connected between the respective grounding poles, the energy withstand capability is insufficient, and coordination with the dielectric breakdown voltage of the electric circuit cannot be achieved.

There are the above contradictory problems.

The present invention has been made in view of the above problems, and provides a building grounding type automatic switch that makes full use of the advantage of independent grounding and instantaneously makes the potential difference with other grounding electrodes the same potential during a lightning strike. Things.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In a building such as a building, a lightning rod ground, a power security ground, a weak power supply, a signal ground, and the like are individually and independently provided. In addition, the rising line from the single grounding electrode is connected to the grounding terminal housed in the same grounding terminal box, and the grounding terminals are connected to each other via a building grounding type automatic changeover device. Electrically insulated,
When the potential of one ground pole suddenly rises during a lightning strike, the building grounding system automatic switcher instantaneously operates and connects with the other ground pole,
An object of the present invention is to provide a building grounding type automatic switching device in which all grounding electrodes are made equal in potential, and which have a large energy withstand capability and can cooperate with a dielectric breakdown voltage of an electric circuit.

[0014]

The present invention will be described with reference to FIGS. 1 and 2. Each of the individual grounding poles 3, 5, and 6 is provided, and if any one of the grounding poles 3, 5, and 6 is provided (in the figure, a lightning rod is shown). When a large current flows through the grounding pole 3) due to a lightning strike or the like and a high voltage is generated and the potential rises sharply, a spark is discharged somewhere in the grounding system, for example, at the outlet 11 of the electronic device, and the electric power is transmitted through the input line. As a result, since the insulation enters the electronic device 12 and the insulation is further weakened, a spark discharge occurs to the signal ground 13 and a current flows to another ground system (these accident records have been very large in the past). Accordingly, the present invention installs a building grounding type automatic changeover device 10 as shown in the figure, and in the case of an accident, operates within a grounding terminal box 7 so that it operates instantaneously at a voltage much lower than the above-mentioned breakdown voltage. Since it is connected to another grounding pole and bypassed, all the connected grounding systems have the same potential and are safe. FIG. 3 shows the operation of the automatic switch 10 for the building grounding system.
When the potential difference is applied between the terminals 14 and 14 ', a circuit in which a surge absorber 19 and a bifilar-wound resistance wire are connected in series operates instantaneously, and the potential difference increases when the passing current increases. As the voltage increases, the limit voltage also increases.
Discharge occurs during this time, and the potential difference disappears at once (the passing current increases).

As for the electrode material of the discharge gap 17, the electrode of carbon is used because the problem of the following flow does not matter between the ground electrodes. Since the carbon electrode has no fusion or formation of an oxide film, it maintains a relatively smooth surface even when the surface is consumed by electric discharge, so that the gap can be extremely narrowed. It can be operated below the dielectric breakdown voltage.

In addition, it has good heat resistance and extremely high energy resistance.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a building grounding type automatic switch according to the present invention.

As shown in FIG. 1 and FIG. 2, a three-pole single ground electrode is provided for grounding the building. The single pole mounting position of the three poles is such that the lightning rod 1, the down-conducting wire 2 using steel frame, the skeleton grounding pole 3 formed by the underground concrete wall, the communication control grounding pole 5, and the power grounding pole 6 are provided as described above. It is.

Rise line 4 from each of the ground electrodes 3, 5, 6
Are the connection terminals 8, collected and mounted in the ground terminal box 7,
8 ', 8 "..., And further, connection terminals 8, 8', 8"
Are connected to grounding buses 9, 9 ', 9 ",... For each grounding system, and via building grounding type automatic changeover switches 10, 10', 10", which are mounted in the grounding terminal box 7. Are connected to the connection terminals 8, 8 ', 8 ",.

Further, the grounding bus 9, which is arranged in the room,
9 ', 9 "..., For example, a 3P with a ground terminal and a ground pole of an outlet 11 are connected to a bus 9 for a lightning rod, and a signal ground 13 of an electronic device 12 is connected to a bus 9' connected to a ground pole 5 for communication control. If the building grounding type automatic switch 10 is not provided, the electronic device 12 is supplied with power from the outlet 11, and if the potential of the grounding electrode 3 rises, 11 → 12⇒ The fault current flows to the grounding electrode 5 by breaking the insulation of each of them.

A plurality of the building grounding type automatic changers 10 are mounted and housed in the grounding terminal box 7, and as shown in FIG. 3, discharge electrode holding brackets 15, 15 'having connection terminals 14, 14', respectively. And discharge electrodes 16 and 16 'made of carbon, which are held by a set screw 20, are opposed to each other with a discharge gap 17 therebetween, and a bifilar wound resistance wire inserted in a Teflon tube or the like is provided between the discharge electrodes 16 and 16'. 18,
The surge absorber 19 is interposed in series and connected by a screw 21 in parallel with the discharge gap. The temperature label 22 is provided at a visible position so that the performance deterioration of the surge absorber 19 can be recognized from outside.
Is affixed. With this configuration, bifilar wound resistance wire 1
8, the resistance value is determined in accordance with the energy resistance characteristics of the surge absorber 19, so that coordination with the discharge voltage of the discharge gap 17 can be achieved. That is, the value obtained by dividing the discharge start voltage of the discharge gap 17 by the surge withstand capability of the surge absorber 19 is substantially equal to the resistance value of the resistance wire 18, and the current capacity is also greater than the surge withstand capability of the surge absorber 19.

[0022]

As described above, according to the present invention, when a plurality of sets of single grounds are installed, if the grounding terminals are connected and connected by a building grounding type automatic changeover, the advantages of the single grounding can be fully utilized at all times. When the lightning rod strikes, all the grounding poles become the common ground, and there is no potential difference between the respective grounding poles.

In addition, (1) the surge response speed is fast (2) the energy withstand is extremely large (3) even if a continuous fault current other than the surge is accidentally flown,
The appliance does not ignite. (4) It is easy to find when a failure occurs. (5) The operation start voltage is constant. (6) The effect is that it can sufficiently withstand long-term use.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an arrangement of a single grounding electrode, a ground wire termination connection terminal, and a building grounding type automatic switch which are the background of the present invention.

FIG. 2 is an enlarged explanatory view of FIG. 1;

FIG. 3 is a front view showing a building grounding type automatic switch according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lightning arrester 2 Pull-down wire using steel frame 3,5,6 Grounding pole 4 Rise line 7 Grounding terminal box 8,8 ', 8 "Connection terminal 9,9', 9" Grounding bus 10 Building grounding system automatic change-over device 11 Outlet 12 Electronics Equipment 13 Signal ground 14, 14 'Connection terminal 15, 15' Discharge electrode holding bracket 16, 16 'Discharge electrode 17 Discharge gap 18 Bifilar wound resistance wire 19 Surge absorber 20 Screw 21 Set screw 22 Temperature label

Claims (6)

(57) [Claims] 1. In a structure such as a building, when a lightning rod ground, a power security ground, a weak electric power, a signal ground, and the like are separately and independently installed, a lightning strike occurs on the lightning rod and a local voltage on the building floor surface. Even if the voltage rises with respect to the ground, the building grounding type automatic switch connected between the grounding poles will connect the semiconductor type lightning arrester and the bifilar-wound resistance wire so that the grounding poles have the same potential. This is a building grounding type automatic switching device characterized in that a circuit formed by connecting a spark gap made of carbon in parallel to a series circuit is a main component. 2. A resistance value of a resistance wire wound by bifilar is substantially equal to a value obtained by dividing a spark discharge starting voltage of a spark electrode by a surge withstand voltage of a semiconductor lightning arrester, and a current capacity of the resistance wire is a semiconductor. The building grounding type automatic switch according to claim 1, wherein the surge arrester has a surge withstand capability greater than that of the lightning arrester. 3. The building according to claim 1, wherein the resistance wire wound by bifilar is inserted into an insulating and heat-resistant tube such as a Teflon tube to insulate between the wires. Grounding type automatic switch. 4. A building grounding type automatic switch according to claim 1, wherein the semiconductor lightning arrester is a surge absorber. 5. An automatic building grounding system according to claim 1, wherein a temperature label is attached to the semiconductor lightning arrester at a place where the lightning arrester can be seen from the outside so that the performance deterioration can be easily recognized. Switch. 6. A building grounding type automatic switching device according to claim 1, wherein a robust and heat-resistant porcelain container is used as the grounding type automatic switching device.