JPH01268427A - Abnormal voltage suppressor - Google Patents

Abstract

PURPOSE:To improve surge voltage protective capacity by boosting the voltage at a starting electrode arranged closely to a main discharge gap provided across a load to be protected through a booster which is excited by a current flowing through a non-linear resistor connected in parallel with the load. CONSTITUTION:Main electrodes 2, 3 are fixed to lead wires l0, l1 connected to the opposite ends of a load 7 to be protected and the gap between the main electrodes 2, 3 is set to a predetermined value thus forming a discharge gap 1. A single winding booster 5 is connected between 1 starting electrode 4 arranged closely to the main electrodes 2, 3 and the lead wire l0. A non-linear resistor 6 allowing only small current for a voltage lower than a predetermined level and allowing abruptly increased current for a voltage exceeding over the predetermined level is connected between the intermediate terminal of the booster 5 and the lead wire l1. When a surge voltage enters between the lead wires l0 and l1, large current flows through the non-linear resistor 6 to produce a high voltage on the starting electrode 4 thus inducing discharge between the main electrodes 2, 3. Consequently, high surge voltage is discharged through the gap 1 and the load 7 is protected from high voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Fields of Industrial Application] Recently, electronic components or electronic devices have been used in many fields of industry. One thing to keep in mind at this time is the surge resistance of these electronic components and devices. That is,
It is necessary to protect the device from damage due to surges entering from the outside or surges generated due to the operation of components inside the device. The present invention relates to an abnormal voltage suppressing device configured to prevent excessive surges, that is, abnormal voltages from being applied to these parts and devices.

[Conventional technology]

There are various methods to suppress abnormal voltage.

A device has been devised and manufactured. These are filters,
Nonlinear resistances are so-called varistors, discharge gaps, or combinations thereof. When the energy of the surge is large, a discharge gap is often used. Figure 3 shows an example of the configuration of a conventional abnormal voltage suppression device. Figure 0 shows the main electrode 22.
．． 23 are arranged facing each other to form a discharge gap 21, which is connected between both terminals of a load 24 to be protected by insulation,
An example is shown in which excessive surge 25 entering from the outside is prevented from being applied to the load. However, as shown in FIG. 4, the discharge characteristics of the discharge gap configured in this way have a characteristic in which the discharge voltage depends on the product of the distance between the main electrodes and the pressure of the gas existing in the discharge space. ing. For this reason, the withstand voltage of the load is 1. in the figure. If the discharge gap is smaller than , the load cannot be protected by the discharge gap having such a configuration.An example of a countermeasure for this case is the method shown in FIG. The principle of this method is as follows. That is, first, a voltage indicated by 30 is applied between the main electrodes 32 and 33. If this continues, the gap between the two electrodes will not cause dielectric breakdown, but if the voltage shown at 30 is applied, the gap between the two electrodes will not cause dielectric breakdown.
is connected to the starting electrode 34 by closing the switch 35, causing a breakdown between the main electrode 33 and the starting electrode 34, and forming an arc plasma indicated by the reference numeral 40, as shown in FIG. This plasma spreads between the main electrodes 32 and 33, causing dielectric breakdown between the main electrodes and forming arc plasma indicated by reference numeral 41. Here, the switch 35 has the symbol 30
A part of the surge voltage that is meant by is taken out using a voltage dividing resistor, etc., and it can be thought of as a semiconductor element that is turned on by this voltage.

By configuring the discharge gap in this way, even if the voltage applied between the main electrodes 32 and 33 is lower than the discharge voltage due to the main electrodes alone, the triggering arc plasma generated at the starting electrode will cause a discharge between the main electrodes. can be generated.

(Problems to be Solved by the Invention) The problems with the abnormal voltage suppression device configured as shown in Fig. 6 are as follows.In other words, in the abnormal voltage suppression device configured as described above, the second power source is When the battery is discharged, the terminal voltage decreases, and it is necessary to constantly consider the replacement period and lifespan, which is inconvenient from a practical standpoint, and there are problems in that the reliability of operation of the device decreases.

In view of the above problems, an object of the present invention is to provide a discharge gap in which a discharge occurs at a voltage far lower than the discharge voltage generated by only the main electrode without using a second power source, and to control this discharge gap by using a second power source. This is done without using a power source and according to the characteristics of the nonlinear resistance that makes up the abnormal voltage suppression device, and as a result, the voltage peak value applied to the protected object, that is, the protection characteristics of the device, is maintained by the nonlinear resistance. The amount of surge energy that can be handled has been increased. Moreover, it is an object of the present invention to provide an abnormal voltage suppressing device with high discharge resistance, which does not cause damage to the nonlinear resistor itself.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, in an abnormal voltage suppressing device including a nonlinear resistance connected between both terminals of an object whose insulation is to be protected from surges, Connected.

A three-electrode discharge gap consisting of two main electrodes and one starting electrode, and a booster in which the output winding is excited using a connecting current between one of the main electrodes of the 3111-pole discharge gap and the starting electrode. It shall be equipped with a transformer.

[Effect]

As is well known, when the voltage applied between the terminals of a nonlinear resistor is less than a certain value, the current that passes through it is extremely small, and when the voltage exceeds this value, the resistance suddenly decreases and the current that passes through it suddenly decreases. It has the property of increasing. Therefore, for example, if the primary winding m (input winding) of a step-up transformer is connected in series with a nonlinear resistor and connected between both terminals of the object to be protected, the waveform of the incoming surge voltage will have a certain value. Until reaching , this voltage is mostly borne by the nonlinear resistance,
When this value is exceeded, the resistance of the nonlinear resistor suddenly decreases,
Almost the full voltage is applied to the primary -1IvA.

This generates a high voltage in the secondary winding (output winding & I) of the step-up transformer, which in turn generates a high voltage in the main electrode of the three-electrode discharge gap.
A trigger plasma is formed by applying a voltage between the two main electrodes and the starting electrode, and a discharge occurs between the main electrodes. Since this discharge occurs before the peak value of the surge voltage is reached, the peak value of the surge voltage is not applied to the nonlinear resistance element, and therefore there is no need to absorb large amounts of energy, and it can be avoided from being destroyed.

In addition, since the energy to be processed by the three-electrode discharge gap is the thermal energy of the arc plasma formed between the main electrodes, it is possible to It is possible to process large amounts of energy while changing the amount of energy that can be processed.

〔Example〕

FIG. 1 shows a first embodiment of the invention, the output winding of a step-up transformer 5 configured as an autotransformer is located between the main electrode 3 and the starting electrode 4 of the three-electrode discharge gap 1. The human power winding is connected in series with the nonlinear resistor 6 and connected between both terminals of the negative ffJ7.

When a surge voltage arrives at the abnormal voltage suppression device configured in this way and the voltage applied to the series circuit of the nonlinear resistor 6 and the input winding of the step-up transformer 5 reaches a certain value, the resistance value of the nonlinear resistor suddenly decreases. Almost the entire voltage is applied to the input winding. As a result, a high voltage is generated between both terminals of the output winding of the step-up transformer 5 and applied between the starting electrode 4 and the main electrode 3, and trigger plasma is generated between the two electrodes. Thereafter, a main discharge is formed between the main electrodes 2 and 3 through the process already described. This main discharge occurs far before the peak value of the surge voltage waveform, and after that the nonlinear resistor 6 and the load 7
Since the voltage applied to the nonlinear resistor becomes almost zero, the surge energy that the nonlinear resistor must absorb is only a small part of the total energy of the surge until the main discharge is formed, and the nonlinear resistor can avoid destruction. can.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, capacitors C, , C□ are connected in series to a nonlinear resistor 6, and when the terminal voltage of capacitor C2 reaches a certain value, a diode 9 The thyristor 8 is operated through the terminal voltage of the series circuit consisting of C+ and Cm to the input SVA of the step-up transformer 5.
It is applied to If you configure the device like this,
The formation of the main discharge is delayed by the time from when the resistance value of the nonlinear resistor 6 begins to rapidly decrease when the surge voltage arrives until the capacitors CI and CI are charged to the predetermined operating voltage, but this time is extremely short; Moreover, the impedance on the power supply side seen from the input sm of the step-up transformer is the surge impedance of the line where the surge voltage arrives and the capacitor C+,
It becomes a parallel impedance with the impedance due to the series circuit of CZ, and the impedance due to the series circuit of capacitors C+ and CI shows a small value for voltages that change quickly such as surge voltage. When the main electrodes 2 and 3 are discharged, the current supplied to the trigger plasma increases, and the discharge between the main electrodes 2 and 3 is more reliably carried out.

〔Effect of the invention〕

As described above, according to the present invention, in an abnormal voltage suppressing device including a nonlinear resistance connected between both terminals of an object whose insulation is to be protected from surges, be done. a three-electrode discharge gap consisting of two main electrodes and one starting electrode, an output SvA is connected between one of the main electrodes of the three-electrode discharge gap and the starting electrode, and an input winding is connected to the nonlinear resistance. Since it is equipped with a step-up transformer that is excited using the passing surge current, the protection characteristics of the abnormal voltage suppression device can be maintained by the nonlinear resistance without using a special starting power source, and the device can be processed easily. Surge energy can be significantly increased. An abnormal voltage suppression device with high operational reliability becomes possible.

[Brief explanation of the drawing]

1 and 2 are the first and second embodiments of the present invention, respectively.
A circuit diagram showing the configuration of an abnormal voltage suppression device according to an embodiment of
Fig. 3 is a circuit diagram showing a configuration example of a conventional abnormal voltage suppression device, Fig. 4 is a diagram showing the discharge characteristics of the abnormal voltage suppression device shown in Fig. 3, and Fig. 5 is a diagram showing the discharge characteristics of the abnormal voltage suppression device shown in Fig. 3. FIG. 6 is a circuit diagram showing a conventional starting method, and is an explanatory diagram showing the starting principle of a three-electrode discharge gap. 1, 21.3t: Discharge gap (3-electrode discharge gap'), 2. 3.22.23.32.31 Main electrode,
4°34: Startup 118i, 5: Step-up transformer, 6: Nonlinear resistance, 7.24F load, 25: Surge. Figure 1 Figure 3

Claims (1)

[Claims] 1) In an abnormal voltage suppressor equipped with a non-linear resistance connected between both terminals of an object whose insulation is to be protected from surges, two main electrodes and one activation are connected between both terminals of said object. using a three-electrode discharge gap consisting of an electrode, an output winding connected between one of the main electrodes of the three-electrode discharge gap and a starting electrode, and an input winding passing a surge current through the nonlinear resistor. An abnormal voltage suppression device characterized by comprising a step-up transformer that is excited.