JP3269018B2 - Lightning arrester for combined light electric circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In recent years, automation has become widespread in factories and research laboratories, offices and hospitals, golf courses and other sports facilities, agricultural facilities, etc., and accompanying this, there are many precision electronic devices. It is used.
Those devices are truly vulnerable to lightning surges.

A lightning surge voltage enters not only from the power supply side but also from the side of a weak electric circuit such as a signal circuit. Therefore, it is naturally necessary to provide lightning protection on these two sides. Among the above facilities, there are strong lightning areas such as heavy lightning areas and winter lightning,
In addition, if the location conditions are mountainous areas, riverbeds, or dune areas, the ground resistivity at that location will be high, so the lightning current will not be immediately dissipated into the ground, but will propagate through the nearby electric line and spread widely. Damage is also greater.

On the other hand, as automation advances, unmanned facilities increase. If the lightning arrester breaks down due to unmanned operation, maintenance personnel will have to be dispatched from a distance. Therefore, the demand for lightning arresters will continue to increase in the future, but it will withstand much more energy than conventional ones, and will not only protect precision equipment from the anti-double penetration of a strong lightning surge voltage,
There is a strong demand for lightning arresters that are designed to prevent burnout of the lightning arrester itself because of the ease of maintenance and the reduction of management costs.

Generally, the spark discharge gap has a characteristic that the surge withstand is large and the response speed is slow, and the semiconductor lightning arrester has the characteristic that the surge withstand is small and the response speed is fast. A means of connecting the lightning arresters in parallel and cooperating with each other has been sought.

However, the discharge starting voltage of the spark discharge gap varies to some extent, and may change over time (the performance may change with the date and time).

Since the characteristics of the semiconductor lightning arrester are also complicated (for example, the characteristics of the devices exhibit some variation), it is not always easy to cooperate with the operation of the two devices, and it is difficult to manufacture them in mass production. there were.

[0007]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 59-4485
No. 1 has the following description.

As shown in FIG. 1, a resistor 2 having a large voltage-dependent nonlinear coefficient and a series connection of a resistor and a linear resistor 1 'having a small voltage-dependent nonlinear coefficient connected in series to the resistor 2. And a spark gap 3 connected in parallel to the terminals 4 and 6 are disclosed.

In FIG. 1, when the surge current is switched from the resistance element 2 having a large voltage-dependent nonlinear coefficient to the spark discharge gap 3 when the surge current is switched, the spark gap 3 and the voltage-dependent nonlinear coefficient are small. The operation coordination with the resistance element 2 having a large value is realized, and the gap of the spark discharge gap 3 does not need to be finely adjusted.

However, in order to facilitate operation coordination between the spark discharge gap 3 and the resistance element 2 having a large voltage-dependent nonlinear coefficient, a resistance element or a linear resistance element 1 'having a small voltage-dependent nonlinear coefficient is connected in series. If the surge arrester is connected to a weak signal circuit for signals, the limit voltage of the surge arrester rises to a voltage at which sparks are generated in a short time before the spark discharge gap discharges, and the voltage is reduced. Since the voltage is applied to a low protected device, the protected device may be damaged.

[0011]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention not only protects precision equipment from repeated intrusion of a strong lightning surge voltage within a stable limit voltage, but also solves the above-mentioned problems. Considered to prevent burning of the arrester itself,
The lightning arrester for combined low-voltage and low-voltage lightning for easy maintenance and reduction of the management cost is as follows.

A composite lightning arrester inserted between a signal line and the ground to protect light electrical equipment from a high energy lightning surge caused by a lightning strike, comprising a non-inductive metal resistor, a semiconductor lightning arrester, a spark discharge gap, Equipped with a heat-resistant and insulating container,
The above-mentioned semiconductor type resistance element and the following maximum surge current resistance I _O
A bifilar-wound or Airton-Perry-wound Nichrome wire having a larger current capacity or a series structure of the non-inductive type metal resistor, which is a similar metal resistor, is connected in parallel to the spark discharge gap. Or a plurality of units are incorporated in the heat-resistant and insulating container, and both ends of the non-inductive metal resistor are a. b. Both ends of the semiconductor lightning arrester are c. d. Then, apply both ends of the spark discharge gap to e. f. And f. And a. Between the input terminals, b. And c. A load-side terminal, d. And e. Are connected to the ground terminals, and the resistance value R _A of the non-inductive resistor is calculated by the equation R _A ≧ (V _S
-V) / _IO , wherein the lightning arrester for the composite light circuit (where V _{S in the} above formula is used)
Is the discharge starting voltage of the spark discharge gap, V is the operating voltage of the semiconductor lightning arrester, and _IO is the maximum surge current withstand capability of the semiconductor lightning arrester.

Further, a thermo label is adhered to the semiconductor type lightning arrester and inserted into a fuse tube type container to be integrated.

In general, in a weak signal circuit for signals, when the spark discharge gap operates, there is no fear that the current will flow from the power supply unit. However, since the operating voltage of the semiconductor-type resistance element is low, the discharge start voltage is applied to the spark discharge gap. Is required to be uniform and low. In addition, a high-voltage large current shunted from the lightning current that penetrates the ground wire, etc., penetrates, so it does not rust, it does not melt, and it can withstand high temperatures. A metal electrode with a high resistance is required.

FIG. 3 shows a bifilar-wound or Airton-Perry-wound nichrome wire or a similar metal resistor and a semiconductor-type lightning arrester, and a spark gap is further added to a structure in which they are connected in series. The impulse current (8
/ 20 μs) is shown.

The current-voltage characteristic curve of the portion where the nichrome wire is bifilar wound or air-ton-perry is:
Regardless of the waveform of the impulse current, it becomes a straight line at a fixed rate as shown by the dashed line (b).

In a circuit in which a semiconductor lightning arrester and the above-mentioned non-inductive type resistor are connected in series, the current / voltage curve in a normal case is the sum of the potential rises of both, so that a chain line (c) is obtained.
Operation of the spark gap becomes P _{1 'point,} upon the solid line is the current-voltage characteristic curve of the semiconductor-type lightning protection device (a), can be safely commutated in the same P ₁ point and the operating voltage V of the semiconductor-type lightning protection device . The spark discharge starting voltage in this case is V
_S , the resistance value of the resistor is R _A , the operating voltage of the semiconductor type device is V, and the maximum surge current resistance I _{O of the} semiconductor type lightning arrester is
Is V _S ≦ ( _RA × _IO + V).

However, the current capacity of the nichrome wire is a current capacity larger than the surge current withstand value of the semiconductor lightning arrester.

[0019] _'If increased, the discharge starting voltage of the spark gap P _2' discharge start voltage V _S of the spark gap is V _S by fluctuate becomes a point, on the characteristic curve of the semiconductor-type lightning protection device (a) in becomes P ₂ points, therefore the semiconductor-type lightning protection device is safe enough, the protected appliance described above is because it is connected in parallel with sufficiently securely protected semiconductor-type lightning protection device, necessary for starting a spark discharge Not directly receiving potential rise, within the limit voltage of the semiconductor lightning arrester, within the limit voltage of the semiconductor lightning arrester, not only protects precision equipment from repeated intrusion of strong lightning surge voltage, but also protects the lightning arrester itself from burning, Management costs can be reduced.

According to the present invention, a signal current flows through a non-inductive type metal resistor, while being connected between a signal weak electric circuit and the ground.
Many of the signals are transmitted at high speed and in large quantities like digital signals.On the other hand, when the lightning arrester operates, the shunt of the lightning current often acts as described above, so there is no residual inductance and there is no surge current. A non-inductive type metal resistor with a large withstand capacity, separating the input side terminal and the load side terminal,
As described above, it is an important element of the present invention that the load-side terminal is connected to an intermediate portion of a structure in which a non-inductive metal resistor and a semiconductor lightning arrester are connected in series.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is designed not only to protect precision equipment from repeated intrusion of a strong lightning surge voltage within a stable limit voltage, but also to prevent the lightning arrester itself from burning.
This is a composite low-voltage surge arrester for light electrical circuits to facilitate maintenance and reduce management costs. The embodiment will be described in detail with reference to FIG.

FIG. 4 is a partial cross-sectional view for connection to a weak signal line. And 1 is heat-resistant made of porcelain etc.
An insulating container, 1a, 1a 'is a base for mounting a spark gap 2 provided horizontally inside the above 1 and 1b, 1b.
, 1b '', 1b '''' are female screws adhered into holes provided in the heat-resistant and insulating container, 2a and 2b are carbon spark electrodes, 2c is an appropriately adjusted gap, and 3 is a fuse tube. Type lightning arrester, 3a is a semiconductor type lightning arrester, 3b is a thermo label attached to the above 3a, 3c is a fuse tube type container, 3
d, 3d 'are fuse holders, 4 is a non-inductive resistor obtained by winding a metal resistance wire such as a nichrome wire in a Teflon tube, and wound by bifilar, 5 is an input terminal, 6 is an output terminal, and 7 is a ground terminal. 7a, 7a with double bottom metal plate
'Is a screw fixing the bottom metal plate to the above container, and 7
b and 7b 'are holes for mounting the lightning arrester, 8a and 8b are connecting metal plates, and 10 is for fastening and connecting the fuse holder a with the base 2a inside the container 1 and the carbon electrode 2b. Bolts and nuts, 10 'are metal rings inserted for the purpose of packing in the gaps of the above-mentioned intermediate portions,
11, 11 'and 11''are connection screws.

[0023]

According to the present invention, when a steep surge with a large change width due to a near point lightning strike or a continuous current type surge current of a long wave tail lightning or multiple lightning arrives, a spark gap operates to back up the semiconductor lightning arrester. Thus, the deterioration of the element can be prevented. In addition, since the protected device is connected in parallel with the semiconductor lightning arrester, it does not directly receive the voltage rise when the spark gap operates, and the terminal voltage of the protected device is limited to the voltage of the semiconductor lightning arrester. Within.

In the signal weak electric circuit of the device to be protected, the above-mentioned bifilar-wound or Airton-Perry-wound two-chrome wire or a similar metal body is connected in series, but these resistors are not provided. Since it is an inductive resistor and has a small resistance value, a general weak signal circuit for a signal hardly affects the operation function of the protection device.

When a bifilar wound nichrome wire or a similar metal resistor connected in series to the semiconductor lightning arrester is used, the stray capacitance between the windings causes a steep change even if the change width is large. Since no pulsed lightning surge is passed, there is no voltage drop due to resistance, so the spark gap does not operate, and the series-connected semiconductor lightning arresters are not damaged, preventing unnecessary operation of the spark gap. And the life of the spark gap can be kept long.

Also, since fine gap adjustment of the spark gap is not required, it is a high-performance lightning arrester and suitable for mass production.

The semiconductor lightning arrester is housed in a fuse-tube type container, and a thermo label is adhered to the surface of the semiconductor lightning arrester. Since the color of the thermolabel adhered to the surface of the element changes, it can be visually confirmed from the outside that the element has deteriorated. In addition, since the fuse tube type container is detachable from the main body, maintenance and inspection are easy.

As described above, the lightning arrester for a combined light circuit according to the present invention is completely ideal as a lightning arrester for a light electric circuit.

[Brief description of the drawings]

FIG. 1 is an internal connection diagram of a conventional lightning arrester.

FIG. 2 is an internal connection diagram of the lightning arrester for the combined type light electric circuit of the present invention.

FIG. 3 is a diagram illustrating the operation principle of the lightning arrester for the combined type weak electric circuit according to the present invention.

FIG. 4 is a partial cross-sectional view of a lightning arrester for a composite type weak electric circuit according to the present invention.

Claims (2)

(57) [Claims] A lightning arrester inserted between a signal line and the ground to protect light electrical equipment from high-energy lightning surges caused by a lightning strike, comprising a non-inductive metal resistor, a semiconductor lightning arrester, and a spark discharge. A gap, a heat-resistant / insulating container, the semiconductor-type resistance element, and a bifilar winding having a current capacity larger than the maximum surge current withstand capability _{IO described} below,
Alternatively, one or a plurality of units in which a series structure of the non-inductive type metal resistor, which is a Nichrome wire wound by Airton Perry or a similar metal resistor, is connected in parallel to the spark discharge gap, the heat resistant / insulated A. The two ends of the non-inductive metal resistor are a. b. Both ends of the semiconductor lightning arrester are c. d. Then, apply both ends of the spark discharge gap to e. f. And f. And a. Between the input terminals, b. And c. A load-side terminal, d. And e. Are connected to the ground terminals, and the resistance value _RA of the non-inductive type resistor is calculated by the following formula: _RA ≧ (V _S −
V) / _IO , wherein the lightning arrester for the composite light circuit (where V _{S in the} above formula is used)
Is the discharge starting voltage of the spark discharge gap, V is the operating voltage of the semiconductor lightning arrester, and _IO is the maximum surge current withstand voltage of the semiconductor lightning arrester. 2. A light electric circuit according to claim 1, wherein a thermo label is adhered to said second semiconductor type lightning arrester and inserted into a fuse tube type container to be integrated. Lightning arrester.