JP4748673B2 - Grounding system - Google Patents

Description

  The present invention, for example, when a high-rise structure such as a steel tower in a fixed radio base station or a lightning rod attached thereto is subjected to a lightning strike, various electrical equipment (including communication equipment) in the base station, The present invention relates to a grounding system for preventing lightning damage from spreading to electrical facilities of general consumers connected to the same power distribution system.

Conventionally, various grounding systems of this type have been provided. For example, a “lightning failure reduction device in a building” described in Patent Document 1 is known.
In this conventional technology, a plurality of surrounding grounding poles that are grounded within a building site, a conductive wire that conducts the surrounding grounding poles, and a remote grounding that is provided at a position away from the building so as to surround the building. And a connecting wire for connecting the surrounding grounding electrode or the conducting wire and the remote grounding electrode.

According to the above configuration, since the entire range extending from the site surrounding the building to the remote grounding electrode is the same potential in a wide range, and an electrically flat region can be realized in a wide range, an electrically projecting portion that is easy to strike lightning. There is no lightning, and lightning strikes can be prevented.
Also, when a thundercloud approaches a building, it approaches the remote grounding electrode with the same potential as that building faster than approaching the building, so even if lightning strikes, by lightning to the remote grounding electrode earlier than the building, It has effects such as avoiding lightning strikes on buildings.

Japanese Patent Laying-Open No. 2004-278118 (paragraphs [0009] to [0015], FIG. 1, FIG. 2, etc.)

  In the prior art according to Patent Document 1 described above, it is an essential requirement to provide a remote grounding electrode having the same potential as the surrounding grounding electrode in the building site in a state where no lightning current flows. In some cases, the site of a building is narrow and remote grounding poles cannot be installed within the same site at a predetermined distance. In that case, it was necessary to acquire a new site or to rent the site in order to secure a place for installing the remote grounding electrode, and these procedures and costs were a heavy burden.

  Accordingly, the problem to be solved by the present invention is to provide a simple grounding structure that prevents lightning damage from spreading to general consumers of the same power distribution system that is receiving electricity jointly with various electric facilities without providing a remote grounding pole. To provide a system.

In order to solve the above-mentioned problem, the grounding system according to claim 1 is intended for a common power distribution system in which a general customer and a specific customer can jointly receive power from an incoming distribution line. In the grounding system for protecting the electrical equipment of the specific consumer that receives power through the lightning-resistant transformer from lightning damage,
A lightning rod installed in a high-rise structure installed in the premises of the specific consumer;
A down conductor connected to this lightning rod,
An equipotential grounding electrode to which the lightning-resistant transformer, the electrical equipment of the specific consumer, the high-rise structure and the down conductor are commonly grounded;
A deeply buried insulated independent ground electrode connected to the primary side of the lightning-resistant transformer via a low current distribution voltage continuous current arrester, and buried deep in the ground;
With
The deep buried insulated independent ground electrode is buried in the site of the specific consumer.

  A grounding system according to claim 2 is the grounding system according to claim 1, wherein the ground connection point of the two continuity blocking lightning arresters connected to the primary side of the lightning-resistant transformer is connected to the deep buried insulation independent grounding. It is connected to the pole.

  According to the present invention, even if a lightning rod receives a direct lightning strike, the potential of the equipotential grounding electrode rises, and even if a surge voltage is applied between the primary side and the secondary side of the lightning-resistant transformer, the potential is within the design value. It is possible to prevent an overvoltage from being applied to the electrical equipment of a specific consumer or the electrical equipment of a general customer by stopping the insulation with the insulation capability of the lightning resistant transformer at the time of rising.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Fig.1 (a) is a block diagram which shows embodiment of this invention. In FIG. 1A, 10 is a high-voltage distribution line, 11 is a distribution transformer whose primary side is connected to the high-voltage distribution line 10, and 13 is a lead-in distribution line connected to the secondary side of the distribution transformer 11. Note that the secondary side of the distribution transformer 11 is grounded by a B-type ground electrode 14.

Here, the lead-in distribution line 13 is drawn into the specific consumer 50 side, and the specific consumer 50 is, for example, a fixed wireless base station.
In addition, the lead-in distribution line 13 is drawn into the house 21 of the general customer 20 from the secondary side of the distribution transformer 11, and the specific customer 50 and the general customer 20 constitute a joint power distribution system. ing.

In the specific customer 50, 30 is a power supply safety device, a lightning-resistant transformer 32 whose primary side is connected to the lead-in distribution line 13, and two continuity blocking lightning arresters connected to the primary side of the lightning-resistant transformer 32. 31 and 31 are provided. In addition, as shown in FIG.1 (b), each continuity prevention lightning arrester 31 is comprised by connecting the lightning arrester 31a and the reactor 31b in series.
Further, a rectifier circuit 34 for rectifying and smoothing an AC voltage to obtain a DC power supply voltage is connected to the secondary side of the lightning proof transformer 32, and a radio equipment to which a DC power supply voltage is supplied on the DC output side. An electrical facility 35 (including a communication facility in the same manner as described above) 35 is connected. Reference numeral 36 denotes an antenna which is connected to the electrical equipment 35 and attached to a steel tower 40 described later.

  A deeply buried insulated independent ground wire 37 is connected to a connection point between the continuous current blocking lightning arresters 31 in the power supply safety device 30, and this ground wire 37 is inserted through an insulated cable or an insulating member 38 to be underground. It is buried deeply and grounded by a deep buried insulated independent ground electrode 39. Here, the embedding place of the deep embedding insulated independent ground electrode 39 is within the site of the specific customer 50.

  Furthermore, a steel tower 40 as a high-rise structure is constructed on the site of the specific customer 50 so as to be isolated from the electrical equipment 35, and a lightning rod 41 is installed on the top of the steel tower 40. In addition, the lightning rod 41 is connected to a down conductor 42, and the down conductor 42 is installed along the steel tower 40 and connected to an equipotential ground electrode 43 as a station ground electrode. The equipotential grounding electrode 43 is connected to the tower leg of the steel tower 40 and the ground terminals of the lightning-proof transformer 32, the rectifier circuit 34, and the electrical equipment 35 described above. It is comprised by the cyclic | annular low resistance mesh grounding material.

Next, the operation of this embodiment will be described.
Now, when the lightning rod 41 is subjected to direct stroke, the lightning surge current I _s flows to equipotential ground electrode 43 via the down conductor 42. At this time, if the ground resistance of the equipotential ground electrode 43 is R _e , a ground potential rising voltage having a magnitude of I _s × R _e is generated.
Conventionally, as a power supply safety device, for example, as shown in FIG. 2 (a), two continuous current blocking arresters 310 including a fuse 311 and a discharge element 312 are connected in series, or as shown in FIG. 2 (b). Two varistors 313 connected in series are used, and the power supply safety device ground terminal E is connected to the equipotential ground electrode 43. When such a power supply security device is used, the ground potential rising voltage during lightning strike is applied to the power supply security device of FIG. 2 (a) or FIG. It tries to spread to the general consumer 20 and the B class grounding electrode 14 side of FIG. 1 via the distribution line 13 '.

  However, in the embodiment of the present invention, the ground connection point of the primary current blocking arrester 31 on the primary side of the lightning proof transformer 32 is grounded by the deeply buried insulated independent ground electrode 39. This deep buried insulated independent ground electrode 39 is electrically separated from the equipotential ground electrode 43 and becomes independent ground, and the ground potential rise voltage of the equipotential ground electrode 43 is the insulation withstand voltage of the lightning proof transformer 32. If it is below, the potential of the incoming distribution line 13 does not increase, so that the electric equipment of the general consumer 20 is not destroyed or the human body is not damaged such as electric shock.

  Further, in FIG. 1, lightning protection against surge voltage caused by induced lightning entering from the distribution transformer 11 and abnormal voltage intrusion caused by a mixed contact accident between the high-voltage distribution line 10 and the low-voltage distribution line (lead-in distribution line 13). It will be discharged to the deeply buried insulated independent grounding pole 39 side via the continuity blocking lightning arrester 31 on the primary side of the transformer 32, preventing the potential of the lead-in distribution line 13 from rising, and general consumers 20 and specific consumers 50. In contrast, lightning surges and other abnormal voltages can be reduced, and various electric facilities are not affected.

As described above, according to the present embodiment, the ground connection point of the primary current preventing arrester 31 on the primary side of the lightning-resistant transformer 32 is grounded by the deep buried insulated independent ground electrode 39 in the site of the specific customer 50. This eliminates the burden of procedures and costs associated with land acquisition and borrowing when a remote grounding electrode is provided as in the past, and ensures that various electric facilities of general customers 20 and specific customers 50 are protected from direct lightning strikes and induced lightning. Can be protected.
In addition, since a deep buried insulated independent ground electrode 39 or the like may be added to the existing grounding system in terms of circuit configuration, construction at a low cost is possible.

  In the configuration of FIG. 1, when the low-resistance grounding cannot be taken as the equipotential grounding electrode 43, a special pulling conductor (not shown) using a high-insulation cable is used without using the pulling conductor 42 of FIG. ) To separate the grounding side from the equipotential grounding electrode 43 and construct and connect another deep buried insulated independent grounding electrode similar to the deep buried insulated grounded electrode 39 to form a more excellent overall grounding system. You can also

In the above-described embodiment, the description has been made with respect to a single-phase power distribution system, but the present invention can also be applied to a three-phase power distribution system.
FIG. 3 is a configuration diagram of main parts when the present invention is applied to a three-phase power distribution system. In FIG. 3, 11A is a distribution transformer, 13A is a lead-in distribution line, 30A is a power supply security device, 32A is a lightning resistant transformer, and the other components are given the same numbers as in FIG. In this case, in the power supply safety device 30A, if three continuation blocking lightning arresters 31 are connected to the primary side of the lightning proof transformer 32A and the ground connection point is connected to the deep buried insulated independent ground electrode 39 as described above. good.

It is a block diagram which shows embodiment of this invention. It is a block diagram of the conventional power supply security device. It is a block diagram of the principal part at the time of applying this invention to a three-phase power distribution system.

Explanation of symbols

10: High-voltage distribution line 11, 11A: Distribution transformer 13, 13A: Lead-in distribution line 14: Class B ground electrode 20: General customer 21: House 30, 30A: Power supply security device 31: Continuity prevention lightning arrester 32, 32A : Lightning-resistant transformer 34: Rectifier circuit 35: Electrical equipment 36: Antenna 37: Deep buried insulated independent ground wire 38: Insulating member 39: Deep buried insulated independent ground electrode 40: Steel tower 41: Lightning rod 42: Down conductor 43: Equipotential ground Pole 50: Specific customer

Claims (2)

Targeting a joint power distribution system that can be jointly received by a general customer and a specific customer from an incoming distribution line, the general customer's electric facility and the specific customer's electrical facility receiving power via a lightning-resistant transformer In a grounding system to protect against lightning damage,
A lightning rod installed in a high-rise structure installed in the premises of the specific consumer;
A down conductor connected to this lightning rod,
An equipotential grounding electrode to which the lightning-resistant transformer, the electrical equipment of the specific consumer, the high-rise structure and the down conductor are commonly grounded;
A deeply buried insulated independent ground electrode connected to the primary side of the lightning-resistant transformer via a low current distribution voltage continuous current arrester, and buried deep in the ground;
With
A grounding system characterized in that the deep buried insulated independent grounding electrode is buried in the site of the specific consumer. The grounding system according to claim 1, wherein
A grounding system characterized in that the ground connection points of the two continuity blocking lightning arresters connected to the primary side of the lightning-resistant transformer are connected to the deeply buried insulated independent grounding pole.

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