JPS63302726A - Surge absorber unit - Google Patents

Abstract

PURPOSE:To suppress voltage with respect to lightning voltage having high energy, by placing an inductance element between line side and machinery side. CONSTITUTION:Upon intrusion of lightning voltage ES through a signal transmission path T, one of two arresters A, A functions. When the lightning voltage ES rises sharply and the arrester A responds slowly, one of two line side nonlinear voltage elements Z1, Z1 functions to back up slow function of the arrester. Magnitude of lightning voltage intruding into a central machinery M is suppressed by machine side nonlinear voltage elements Z2, Z2, but since lightning current flowing therethrough is blocked by an inductance element L to low level, voltage limit of the nonlinear voltage elements Z2, Z2 can be suppressed to low level correspondingly, Furthermore. voltage limit of the arresters A, A can be selected to low level for a transmitted signal.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is applicable to systems that connect remotely installed external equipment and central equipment via signal transmission paths, such as large-scale computer control systems and fire alarm systems. This invention relates to a surge absorber unit that is used to effectively protect central equipment from lightning voltage that enters through signal transmission paths or power lines in systems constructed by connecting between the two.

Conventional technology In large-scale computer control systems, fire alarm systems, etc., external devices such as various sensors and operation terminals are installed far away from the central device, and there are various connections between these external devices and the central device. They are connected via a signal transmission path using a cable.

In these systems, especially when the signal transmission path is an outdoor cable, the central equipment may malfunction due to lightning voltage that enters through the signal transmission path.
It is necessary to take sufficient measures against lightning to prevent damage.

Therefore, the conventional method of countermeasures against lightning is as follows:
It depends on the contents of the system on a case-by-case basis, and there are quite a number of ways to do it. The question is how to attenuate, absorb, and stop it before it invades.

Among these lightning countermeasures, it is the most common, and
A widely used circuit is one in which a symmetrical π-type circuit is constructed between two wires forming a signal transmission path and a lightning arrester by a resistor R and a voltage nonlinear element 2 (FIG. 3). In this device, the lightning voltage that enters through the signal transmission path connected to the line side terminals Ll and L2 is first limited in its peak value by the lightning arrester A, and then the current is limited by the resistor R. At the same time, by discharging current from the ground terminal E to the earth using the voltage non-linear element Z, the magnitude of the lightning voltage at the equipment side terminals TI and T2 is reduced to less than the impulse withstand voltage of the central equipment connected thereto. It is something that we are trying to suppress.

Problems to be Solved by the Invention According to the prior art, the lightning arrester A can have a low limiting voltage, but there is a limit to the response speed based on the discharge delay time, and the voltage non-linear element Z has a low limit voltage. , the response is fast and the energy withstand is large, but the limiting voltage cannot be made low enough, and although the resistor R has a current limiting function, it does not have the ability to block high frequencies. The problem is that the voltage suppression performance against high-energy lightning voltages is not necessarily sufficient.

Therefore, in view of the problems of the prior art, an object of the present invention is to skillfully complement the characteristics of each component, thereby achieving
An object of the present invention is to provide a new surge absorber unit that can exhibit sufficient voltage suppression performance even against steep and high-energy lightning voltages.

Means for Solving the Problems The configuration of the present invention to achieve the above object is to provide a ground terminal in addition to each pair of line side terminals and equipment side terminals, and to connect the corresponding line side terminals and equipment side terminals. An inductance element is inserted between each line side terminal and the ground terminal, respectively. The gist is that a parallel circuit of a positive nonlinear element and a lightning arrester is interposed, and a voltage nonlinear element is interposed between each equipment terminal and the ground terminal.

Therefore, with this configuration, the arrester operates against lightning voltage that does not have much energy and can keep the limiting voltage low, but when the lightning voltage is too large to be removed by the arrester, The voltage non-linear element on the line side operates to remove the energy lightning voltage. In addition, the inductance element limits the lightning current flowing into the voltage nonlinear element on the equipment side, especially its high frequency component, and keeps the limiting voltage sufficiently low, and also prevents the high frequency component of the lightning voltage from flowing into the equipment side. transmission can be prevented.

In general, voltage non-linear elements have a much faster response time than lightning arresters, so they can adequately cope with sudden lightning voltages.

It works as described above.

Example Examples will be described below with reference to the drawings.

The surge absorber unit 10 includes lightning arresters △, A, inductance elements L%L, and voltage nonlinear elements Z1, Zl.
, Z2, and Z2 (Fig. 1).

These components form two π-type circuits symmetrically between a pair of line-side terminals L1 and L2, a pair of device-side terminals T1 and T2, and ground terminals E and E. There is. That is, an inductance element is interposed between the corresponding line side terminals 11, L2 and the equipment side terminals TI, T2, and each line side terminal L1, L2
A parallel circuit consisting of a lightning arrester A and a voltage non-linear element Z1 is interposed between the terminals TI, T2 and the ground terminal E, respectively. , a voltage non-linear element Z2 is interposed.

As the lightning arrester A, it is preferable to use an inert gas-filled high-speed lightning arrester known by the trade name of "gas arrester" or "gas tube arrester", and the DC discharge starting voltage, which is a guideline for the limiting voltage, is equal to the transmission signal voltage. Select the one that is at the top of the list. Incidentally, the response time of the lightning arrester A is 50 nS at maximum.

The inductance element is an air-core coil, and when the transmission signal is an analog signal including a DC level, the inductance is approximately several hundred μH.
Further, when the transmission signal is a high-speed pulse signal, it is preferable to set the value to be considerably smaller than this.

The voltage nonlinear elements Z1, Zl, Zl, and Zl are made of metal oxide semiconductors, and are preferably commercially available under the trade name "rZNR Surge Absorber." response time 5
0 nS and energy withstand capacity of 90 J or more are available.

The surge absorber unit 10 having such a configuration has a signal transmission path T connecting an external device S and a central device M.
Insert and use near central device M (Figure 2)
. However, the earth terminal E shall be connected to the earth in a good grounding condition.

Now, when lightning voltage ES enters through the signal transmission path T, one of the lightning arresters A is activated depending on its polarity.

However, when the rise of the lightning voltage ES is steep and the response time of the arrester A is too slow, one of the voltage nonlinear elements Z1 and Zl on the line side operates to back up the delay to the arrester. can.

On the other hand, the magnitude of the lightning voltage that enters the central equipment M is ultimately suppressed by the limiting voltage of the voltage non-linear elements Z2 and Zl on the equipment side, but the voltage non-linear elements Z2,
Since the lightning current flowing into Zl is blocked by the inductance element and becomes a sufficiently small value, the limiting voltage of the voltage nonlinear element Z2 and Zl can also be correspondingly suppressed to a sufficiently small value. It is.

Roughly speaking, the limiting voltage of the lightning arresters A, A can be selected to be sufficiently low with respect to the transmission signal, while the voltage non-linear elements Z1, Zl, Zl, Zl cannot have the limiting voltage sufficiently low; Since their energy withstand capacity is sufficiently large, the two are complementary to each other in this respect as well.

As an example, when commercially available devices are optimally combined under the conditions of use where the maximum transmission signal voltage is 130 VDC, an 8.
When the lightning voltage ES of X20μ510kV was applied, the peak value of the output voltage appearing between one of the equipment side terminals T1 and T2 and the earth terminal E could be suppressed to a maximum of 320 to 350μ.

This device can be inserted not only into the signal transmission line T but also into an AC or DC high-voltage or low-voltage power line. , it is possible to effectively protect the vessel.

As described in detail, according to the present invention, a pair of line side terminals, a pair of equipment side terminals, and a ground terminal are provided, and an inductance is provided between the corresponding line side terminals and the equipment side terminals. A parallel circuit consisting of a lightning arrester and a voltage non-linear element is interposed between the line side terminal and the earth terminal, and a voltage non-linear element is interposed between the equipment side terminal and the earth terminal. By doing so, the lightning arrester and the voltage non-linear element complement each other in terms of their limiting voltage, response time and energy capacity.
Moreover, the inductance element can suppress the limiting voltage of the voltage nonlinear element on the equipment side to a sufficiently low level by blocking the lightning current, especially its high frequency component, flowing into the voltage nonlinear element on the equipment side. Therefore, there is an excellent effect in that sufficient voltage suppression performance can be exhibited even against steep, high-energy lightning voltages that enter through signal transmission paths or power supply lines.

In addition, since both lightning arresters and voltage non-linear elements are common commercially available elements, their ratings vary depending on the type and voltage value of the transmitted signal on the signal transmission path, or the power supply voltage value on the power line. There is also the practical effect that values can be optimally selected to easily achieve appropriate performance.

[Brief explanation of drawings]

Figures 1 and 2 show examples, Figure 1 is an overall configuration diagram,
FIG. 2 is an explanatory diagram of the usage state. FIG. 3 is a diagram corresponding to FIG. 1 showing a conventional example. Ll, L2...Line side terminals T1, T2...Equipment side terminals E...Earth terminal A...Surge arrester...Inductance element

Claims (1)

[Claims] 1) A pair of line side terminals, a pair of device side terminals corresponding to the line side terminals, and a ground terminal, and an inductance element is provided between the corresponding line side terminals and the device side terminals. A parallel circuit of a voltage nonlinear element and a lightning arrester is interposed between each of the line side terminals and the earth terminal, and a parallel circuit of a voltage nonlinear element and a lightning arrester is interposed between each of the equipment side terminals and the earth terminal. , a surge absorber unit equipped with a voltage non-linear element.