JP3343768B2 - Semiconductor lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor lightning arrester using a semiconductor switching element for protecting a power system from overvoltage caused by lightning strike or the like.

[0002]

2. Description of the Related Art A semiconductor lightning arrester using a semiconductor switching element such as a thyristor element has been developed in order to protect an electric power system from an overvoltage caused by a lightning strike or the like. Such a semiconductor type lightning arrester, for example, has a semiconductor switching element installed between the power system and the ground, and normally keeps the semiconductor switching element off, but when an overvoltage occurs in the power system due to lightning strike or the like, the semiconductor By turning on the switching element instantaneously, the power system is protected from overvoltage.

However, the conventional semiconductor lightning arrester uses either an SCR thyristor or a GTO thyristor as such a semiconductor switching element. Therefore, as a semiconductor switching element, SC
When an R thyristor is used, since there is no thyristor element having a high critical on-current rise rate, there is a possibility that local current concentrated destruction may occur in the thyristor element while discharging a lightning surge current. When a GTO thyristor is used as a semiconductor switching element, there is no element having a high one-cycle surge-on current. there were.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and does not cause current concentrated destruction of a semiconductor switching element due to a lightning surge current or thermal destruction of a semiconductor switching element due to a follow-up current. The present invention has been made in order to provide a semiconductor lightning arrester using a semiconductor switching element.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a semiconductor lightning arrester using a semiconductor switching element, comprising: a semiconductor switching element for discharging a lightning surge current; On- gate operated by the lightning surge current to energize the follow-on current
A semiconductor switching element having a circuit is connected between a power system and the ground.

[0006]

The semiconductor lightning arrester of the present invention is installed between the power system and the ground, and when an overvoltage occurs in the power system due to a lightning strike or the like, the semiconductor switching element is instantly turned on and the power system is grounded. The protection of the system from overvoltage is the same as in this type of conventional semiconductor lightning arrester. However, in the present invention, a semiconductor switching element for discharging a lightning surge current and an on-gate circuit that operates by the lightning surge current to supply a subsequent current after the discharge are provided.
Since both of the provided semiconductor switching elements are connected between the power system and the ground, the GTO thyristor or S is used as a semiconductor switching element for discharging a lightning surge current.
By using an I-thyristor having a high critical on-current rise rate, a large lightning surge current can be discharged. After further discharge lightning surge current, the lightning surge
By using a semiconductor switching element having a high one-cycle surge on-current, such as an SCR thyristor having an on-gate circuit operated by a current, it is possible to prevent thermal destruction due to the energization of a continuous current.

[0007]

The present invention will be described in more detail with reference to the following examples. In FIG. 1, reference numeral 1 denotes a thyristor element provided between the power system and the ground as a semiconductor switching element for discharging a lightning surge current, and 2 is connected in parallel with the thyristor element 1 between the power system and the ground. And a thyristor element as a semiconductor switching element for energizing the follow-on current. Thyristor element 2 for energizing follow-on current
The on-voltage is lower than the thyristor element 1 for discharging the lightning surge current, and the one-cycle surge on current is higher. In the embodiment, the GTO thyristor or the SI
An SCR thyristor is used as a thyristor and a thyristor element 2 for energizing a subsequent flow. The SCR thyristor has a high one-cycle surge-on current.

Reference numeral 3 denotes an on-gate circuit for the thyristor element 1, and reference numeral 4 denotes an on-gate circuit for the thyristor element 2. The on-gate circuit 3 includes a zinc oxide element 5 and a Zener diode 6 as shown in FIG.
And a midpoint A between the zinc oxide element 5 and the Zener diode 6 is connected to the gate signal input line 8 of the thyristor element 1 via the resistor 7. In parallel with the Zener diode 6, a light emitting element 9 such as an LED is provided.
And a resistor 10 are provided.

The operation of the on-gate circuit 3 is as follows. First, when an overvoltage occurs in the power system, the resistance of the zinc oxide element 5 decreases,
Although a current flows through the light emitting element 9, the voltage at the intermediate point A is kept constant by the action of the Zener diode 6. As a result, part of the current flowing through the zinc oxide element 5 is shunted to the gate signal input line 8 of the thyristor element 1 via the resistor 7, and the thyristor element 1 is turned on. The light-emitting element 9 emits light simultaneously with energization.

On the other hand, the on-gate circuit 4 for the thyristor element 2 includes a phototransistor 11 operated by the light emission of the light emitting element 9 and a capacitor 12, and the light emitting element 9
When the light is emitted, the phototransistor 11 is turned on, and the charge stored in the capacitor 12 flows to the gate signal input line 12 of the thyristor element 2 to turn on the thyristor element 2.

In the semiconductor lightning arrester of the embodiment configured as described above, when an overvoltage occurs in the power system, the on-gate circuit 3 operates as described above to operate the GTO thyristor or the STO.
The thyristor element 1 composed of an I thyristor is turned on to discharge a lightning surge current. Since the GTO thyristor or the SI thyristor has a high on-voltage and a critical on-current increase rate, it is possible to discharge a large lightning surge current without causing local current concentrated destruction. Further, a subsequent current flows following the lightning surge current. However, as described above, when the light emitting element 9 emits light due to the lightning surge current, the on-gate circuit 4 turns on the thyristor element 2 composed of an SCR thyristor.
The continuation flow mainly flows to the ground through the thyristor element 2 having an ON voltage lower than that of the thyristor element 1. Since the thyristor element 2 is formed of an SCR thyristor having a high one-cycle surge-on current, it is possible to carry on the continuous current without fear of thermal destruction. In this way, the power system is grounded by the semiconductor lightning arrester, and the power system is protected from overvoltage. The timing at which the thyristor element 2 is turned on can be freely controlled by the capacity of the capacitor 12 and the like. Further, in the present embodiment, the on-gate circuit 4 is operated by an optical signal, but it goes without saying that the specific configuration is not limited to this. FIG. 2 shows the operation waveforms of the device of the present invention described above.

[0012]

As described above, the semiconductor lightning arrester of the present invention comprises a semiconductor switching element for discharging a lightning surge current and a semiconductor switching element for supplying a subsequent current after discharge to a power system. By connecting the power supply to the ground, there is an advantage that the power system can be protected without fear of causing a current concentration destruction of the semiconductor switching element due to a lightning surge current or a thermal destruction of the semiconductor switching element due to a follow-up current.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the device of the present invention.

[Explanation of symbols]

1. Thyristor element as a semiconductor switching element for discharging a lightning surge current, 2. Thyristor element as a semiconductor switching element for supplying a continuation current, 3.
On-gate circuit, 4 on-gate circuit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-276653 (JP, A) JP-A-7-95727 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 3/22 H02H 9/04

Claims (4)

(57) [Claims] In a semiconductor lightning arrester using a semiconductor switching element, a semiconductor switching element for discharging a lightning surge current and a current for flowing a subsequent current after the discharge.
An on-gate circuit that operates by the lightning surge current;
A semiconductor lightning arrester characterized by connecting the obtained semiconductor switching element between a power system and the ground. 2. The semiconductor according to claim 1, wherein the on-voltage of the semiconductor switching element for discharging the lightning surge current is higher than the on-voltage of the semiconductor switching element for energizing the follow current. Type lightning arrester. 3. A semiconductor switching element for discharging a lightning surge current has a higher critical on-current rise rate than a critical on-current rise rate of a semiconductor switching element for energizing a follow current. The semiconductor lightning arrester according to claim 1. 4. A GTO thyristor or a SI thyristor is used as a semiconductor switching element for discharging a lightning surge current, and an SCR thyristor is used as a semiconductor switching element for supplying a follow-up current. 4. The semiconductor lightning arrester according to item 2 or 3.