JPS605734A - Load protecting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention is applicable to cases where a failure such as a load short circuit occurs in a power supply circuit system in which a load such as an insulation test specimen is connected to the power supply circuit, such as during a dielectric strength test. In particular, the present invention relates to a load protection device for quickly diverting fault current to protect a load.

In normal electrical circuits, when a failure such as a load short circuit occurs, a mechanical switch such as a power circuit breaker is used to shut off the power supply circuit. It takes at least several tens of milliseconds of time to complete the process, and the damage to the load is considerable, especially when a high voltage is applied to the load. During dielectric strength testing, the load is usually connected to a high voltage power source.
In order to minimize damage to the load when a failure such as a load short circuit occurs, it is desirable that the time required from the occurrence of the failure until the current is cut off is within several μsec.

Therefore, a discharge gap is provided in parallel with the load, and a pulse signal is applied to the discharge starting electrode at the same time as a load failure occurs, causing a discharge in the discharge gap, and the fault current is bypassed through this discharge gap. . However, in this case, when a failure such as a load short circuit occurs, the voltage applied to the discharge gap decreases, and even if a pulse signal is supplied to the discharge starting electrode to induce discharge, it will be difficult to start the discharge. Become.

Furthermore, when the peak value of the power supply voltage is increased or decreased over time, in a discharge gap whose gap length is fixed, the power supply voltage increases and the voltage applied to the discharge gap becomes higher than the discharge starting voltage of the discharge gap. If so, the discharge will start immediately, and the current in the power supply circuit will be shunted regardless of whether there is a load failure or not.
1. If the power supply voltage decreases and the voltage applied to the discharge gap becomes less than the minimum discharge starting voltage of the discharge gap, it will be difficult to start the discharge even if you try to induce a discharge by giving a pulse signal to the discharge starting electrode. becomes.

The present invention is capable of adjusting the gap length of the discharge gap and the load even when the peak value of the uncircumcised power supply voltage changes over a wide range over time, even when using various types of power supplies such as AC power supply, DC power supply, and impulse power supply. A load that can induce a discharge at high speed and reliably by applying a pulse signal to the discharge starting electrode when a load failure occurs, by always maintaining an appropriate voltage applied to the discharge gap when a failure occurs. It provides a protective device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A load protection device of the present invention will be explained in detail based on an embodiment shown in the drawings.

In Figure 1, 1 is a power source whose peak value of power supply voltage may change continuously or intermittently, such as a DC power source, an AC power source, or an impulse power source used for a dielectric strength test, and 2 is a power source impedance. 3 indicates the power supply voltage. 4 is that the discharge gap 7 can immediately start discharging when a pulse signal is applied to the discharge starting electrode 8, not only in a normal state where the load 5 end is not short-circuited, but even when the load 5 end is short-circuited. This is the impedance for maintaining the discharge gap voltage so that the voltage V applied to the discharge gap 7 can be maintained at a level higher than the minimum discharge voltage.

If the power source 1 is an AC power source, if the voltage V applied to the discharge gap 7 and the voltage ■2 at the load end are out of phase, the instantaneous voltage of the voltage ■1 when a failure occurs at the load end 5 will be the voltage V applied to the discharge gap 7. Since there may be cases where the discharge voltage does not exceed the minimum discharge voltage of 7,
It is preferable that the discharge amount gap voltage holding impedance 4 is constituted by a resistor with small reactance. 5 is a load such as a test specimen during a dielectric strength test, which is connected to the power source 1 in series with an impedance 4 for maintaining discharge gap voltage.

A power supply circuit 13 is configured.

6 is a discharge circuit, and the discharge circuit 6 includes a discharge gap 7.6 formed by a high voltage side electrode 7a and a low voltage side electrode 7b that is movable in the axial direction. It is constituted by a discharge starting electrode 8, and is connected in parallel with the impedance 4 for maintaining the discharge gap voltage of the power supply circuit 1 and the load 5.

Reference numeral 9 denotes a voltage setting device of the power supply 1, and 10 receives a voltage setting signal from the voltage setting device 9 to set the gap length of the discharge gap 7 to an appropriate range, that is, to withstand the peak value of the power supply voltage B, and to start the discharge. A gap length setting device 11 sets a range in which discharge starts immediately when a pulse signal is given to the electrode 8 for discharge, and 11 is provided with an electrode 8 for starting discharge according to the gap length setting signal of the gap length setting device 10. Low voltage side electrode 7b This is a gap length adjustment drive device that moves the discharge gap appropriately in the axial direction to actually increase or decrease the discharge gap length. It should be noted that if the set voltage in the voltage setting device 9 becomes low, the interval length of the discharge interval 7 is made smaller, and conversely, if the set voltage becomes higher, the interval length of the discharge interval 7 is made larger, so that the interval length of the discharge interval 7 is made smaller. The length adjustment drive device 11 is activated.

Reference numeral 12 denotes a pulse generator for applying a pulse signal to the discharge starting electrode 8 in the discharge gap 7 in immediate response to the occurrence of a failure in the load 5. The pulse generator 12 generates pulses in response to the occurrence of a failure in the load 5 using a conventionally known device that detects, for example, an abnormal current in the load 5 and generates pulses in response.

The discharge gap 7 for the power supply voltage B of the power supply 1 mentioned above
The appropriate range of the gap length and the voltage range in which the voltage 1 applied to the discharge gap 7 should be maintained even when the load is short-circuited are as follows:
are interrelated and depend on the discharge characteristics of an individual discharge gap 7. therefore.

First of all, it is necessary to investigate the discharge characteristics such as the relationship between the 50 series flash voltage of the discharge gap 7 and the gap length.
In general, the gap length of the discharge gap 7 is 1.05 of the gap length at which the peak value of the power supply voltage B becomes the 50% flood-over voltage of the discharge gap 7, following the change in the peak value of the power supply voltage.
If the gap length is within this range, the discharge gap voltage holding impedance 4 is the voltage V imposed on the discharge gap 7 when one load is short-circuited, or the peak value of the power supply voltage. It is sufficient to set it to a constant value so as to have a factor of 80 or more regardless of changes in the peak value of the power supply voltage filter.

Next, the operation of the above-described embodiment of the present invention will be explained.

Under normal conditions, following the change in the peak value of the power supply voltage B of the power source 1, the gap length of the discharge gap 7 is kept within the appropriate range already mentioned by the functions of the gap length setting device 10 and the gap length adjustment drive device 11. Retained.

Therefore, if a failure such as a short circuit occurs in the load 5, the discharge gap 7 due to the discharge gap voltage holding impedance 4
Coupled with the function of maintaining the voltage V applied to the discharge gap 7 above the lowest discharge voltage, the discharge gap 7 immediately starts discharging due to the pulse signal applied to the discharge starting electrode 8 at the same time as a load failure occurs, and the failure occurs. The current can be shunted to protect the load 5.

The load protection device according to the present invention is not limited to one in which the discharge gap is a single gap formed by a pair of electrodes, but can be applied to a plurality of discharge gaps as is known in the art as a multi-stage severing gap method. It is also possible to apply the method to a discharge gap composed of gaps, and in this case, the gap length of at least one of the plurality of discharge gaps can be adjusted according to the power supply voltage by the method of the present invention. This can be achieved by making appropriate adjustments.

The present invention provides a gap length setting device that receives a voltage setting signal from the power supply voltage setting device and always maintains the gap length of a discharge gap within an appropriate range by following changes in the peak value of the power supply voltage. In addition to having a gap length adjustment drive device, by connecting an impedance in series with the load connected to the power supply circuit to maintain the voltage applied to the discharge gap at a level higher than the minimum discharge voltage of the discharge gap when a load failure occurs, the type of power supply can be adjusted. Even if the peak value of the power supply voltage changes continuously or intermittently, regardless of the current situation, when a pulse signal is applied to the discharge starting electrode based on the detection of the occurrence of a load failure, the power supply voltage can be immediately and reliably changed. It can start the discharge in the discharge gap and bypass the fault current to the discharge circuit to protect the load.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing one embodiment of the present invention. 1...Power supply, 2...Power supply impedance, 6...
...Power supply voltage, 4...Discharge amount gap voltage holding impedance, 5...Load, 6...Discharge circuit, 7...
・Discharge gap, 8... Electrode for starting discharge, 9... Power supply voltage setting device, 10... Gap length setting device, 11... Drive device for gap length adjustment, 12... Starting pulse generator, 1ro...
・Power supply circuit patent - Applicant: Ube Industries Co., Ltd. Procedural amendment February 3, 1980 Commissioner of the Japan Patent Office 1 Indication of the case Patent application No. 110136/1982 Name of the invention Load protection device 5 Person making the amendment Case and Relationship Patent applicant postal code - 755 1-12-32 Nishihonmachi, Ube City, Yamaguchi Prefecture (020) Ube Industries Co., Ltd. Telephone: 03 (581) 3311 No amendment order. 5. Claims column and Detailed Description of the Invention column of the specification to be amended. 6. Contents of the amendment (1) The amended scope of claims is as shown in the attached sheet. (2) 1 Voltage "Is it l?" on page 7, line 3 of the specification. Correct to "voltage v1". (3) Add ``Yo'' between ``Gap Length Adjustment'' and ``Drive Device'' in the first line of page 8 of the specification. Above is the patent application 1101/1984! The amended claim of No. I6: ``A discharge circuit having a discharge gap is directly connected to a power supply circuit 11, and the voltage applied to the discharge gap when a load failure occurs is defined as the minimum discharge voltage of the discharge gap. A gap length setting device which is connected in parallel with the impedances for holding the discharge gap voltage held as described above and which sets the gap length of the discharge gap in response to a voltage setting signal from a voltage setting device of the power source of the power supply circuit; A load protection device comprising a gap length adjustment drive device that increases or decreases the gap length of the discharge gap according to a gap length setting signal from a gap length setting device.''

Claims (1)

[Claims] A discharge gap voltage holding device that connects a discharge circuit having a discharge gap in series to a power supply circuit, and maintains the voltage applied to the discharge gap at a level higher than the lowest discharge voltage of the discharge gap during load and when a load failure occurs. A gap length setting device is connected in parallel with the impedance and sets the gap length of the discharge gap in response to a voltage setting signal from a voltage setting device of the power source of the power supply circuit; A load protection device comprising a gap length adjustment drive device that increases or decreases the gap length of a discharge gap.