JPH07128376A - Abnormality detector for electric equipment - Google Patents

Abstract

PURPOSE:To simplify the circuitry for transmitting the state change to the low voltage side when an abnormality occurs at a high voltage part to cause state change of a switch element. CONSTITUTION:In a capacitor voltage division potential transformer comprising a coupling capacitor 4 and a first voltage dividing capacitor 5 connected in series and measuring the voltage of a high voltage bus 1, a second voltage dividing capacitor 7 is connected between the coupling capacitor 4 and the high voltage bus 1. A switch element 8 operable upon occurrence of abnormality in an objective electric appliance is connected across the second voltage dividing capacitor 7. Then the switch element 8 is opened or closed, the voltage of the first voltage dividing capacitor 5 varies and occurrence of abnormality is detected based on the voltage variation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for electric equipment.

[0002]

2. Description of the Related Art When an abnormality occurs in an electric device for a high-voltage or extra-high voltage electric system configuration, it is necessary to detect it promptly, and for that purpose, the state of the electric device must be constantly monitored. Required. For example, when a closed cubicle contains a system configuration device such as a circuit breaker, transformer, or current transformer, in order to monitor an abnormal overheat in the conductive part of such a storage device, the conductive part must be An opening / closing element such as a bimetal that responds to heat is installed, and the occurrence of abnormal overheating can be detected from the change in the opening / closing state of the opening / closing element.

In this case, since the conductive portion, and hence the switching element, is located at the high voltage portion, when it is attempted to detect a change in the state of the switchgear at a low pressure portion such as the ground, a signal is sent by the change in the switchgear state. It is necessary to generate the signal and transmit the signal to the ground side through an insulating medium such as an insulating transformer. Therefore, the configuration therefor becomes extremely complicated.

[0004]

DISCLOSURE OF THE INVENTION The present invention, when detecting an abnormality in an electric device, uses an opening / closing element that operates in response to the occurrence of an abnormality in a high-voltage portion in a portion where an abnormality is to be detected. An object is to simplify the configuration for transmitting the state change to the low voltage side.

[0005]

According to the present invention, a coupling capacitor and a first voltage dividing capacitor are connected in series, and this series circuit is connected between a high voltage busbar and ground, and the first voltage dividing circuit is connected. To the capacitor voltage dividing type potential transformer which is connected to the measuring device for measuring the voltage of the high voltage bus across the capacitor,
The second voltage dividing capacitor is connected so as to be located between the coupling capacitor and the high voltage busbar, and a switching element that operates when an abnormality occurs in the electrical device that is the abnormality detection target is connected across the second voltage dividing capacitor. It is characterized in that a measuring device for measuring voltage fluctuation is further connected across the first voltage dividing capacitor.

[0006]

When the switching device is in the ON state when the electric device to be detected as the abnormality is normal, the second voltage dividing capacitor is in the short circuit state, and therefore the voltage according to the voltage dividing ratio of the coupling capacitor and the voltage dividing capacitor. Is obtained by a voltage dividing capacitor. Since this voltage is proportional to the voltage of the high voltage bus bar, the voltage of the high voltage bus bar can be measured by a measuring device. This is not particularly different from the operation of an ordinary capacitor voltage dividing type potential transformer.

When an abnormality occurs in the electrical equipment to be detected, if the switching element changes to the off state, the short-circuit state of the second voltage dividing capacitor is released, and this is connected in series with the coupling capacitor and the voltage dividing capacitor. Will be connected. Therefore, the voltage of the voltage dividing capacitor changes due to the change of the voltage dividing ratio. This voltage fluctuation is detected by a measuring device for voltage fluctuation detection. By this detection, it becomes possible to detect the occurrence of an abnormality in the electric device on the low voltage side.

[0008]

Embodiment An embodiment of the present invention will be described with reference to FIG. 1
Is a high-voltage bus to which the electric device 2 to be detected as an abnormality is connected. Reference numeral 3 is a capacitor voltage dividing type potential transformer, which is composed of a coupling capacitor 4 and a voltage dividing capacitor 5, both capacitors 4 and 5 are connected in series and are connected between the high voltage bus bar 1 and the ground. Reference numeral 6 is a measuring device for measuring the voltage of the high voltage bus bar 1, for example, a voltmeter or a voltage relay.

These configurations are not particularly different from those of a normal capacitor voltage dividing type potential transformer, and a low voltage corresponding to the voltage dividing ratio by the capacitors 4 and 5 is measured as a voltage proportional to the voltage of the high voltage bus 1. 6 is applied. Thereby, the voltage of the high voltage bus bar 1 is measured or an abnormality is detected.

In accordance with the invention, a second voltage dividing capacitor 7 is connected between the coupling capacitor 4 and the high voltage busbar 1. The switching element 8 that operates in response to the occurrence of an abnormality in the electric device 2 is connected across the voltage dividing capacitor 7. Assuming that the abnormality detection target of the electric device 2 is abnormal overheating of the conductive portion, a bimetal is installed near the conductive portion and this bimetal is used as the opening / closing element 8.

Reference numeral 9 is a measuring instrument, for example, a relay, which is connected across the voltage dividing capacitor 5 for measuring voltage fluctuations. This relay is set to operate when the voltage of the voltage dividing capacitor 5 exceeds a predetermined value and fluctuates.

In the above structure, it is assumed that the opening / closing element 8 is in the ON state when the conductive portion of the electric device 2 is in the normal state. Therefore, the voltage dividing capacitor 7 is in a short circuit state,
Therefore, the voltage according to the voltage division ratio of the coupling capacitor 4 and the voltage dividing capacitor 5 is obtained by the voltage dividing capacitor 5. Since this voltage is proportional to the voltage of the high voltage bus, the voltage of the high voltage bus is measured or abnormally detected by the measuring device 6.

When the conductive portion of the electric device 2 is abnormally overheated, the switching element 8 is turned off. Then, the short-circuit state of the voltage dividing capacitor 7 is released, and the voltage dividing capacitor 7
Will be connected in series to the coupling capacitor 4 and the voltage dividing capacitor 5. Therefore, the voltage of the voltage dividing capacitor 5 decreases due to the change of the voltage dividing ratio. This voltage drop is detected by the measuring device 9. By this detection, the occurrence of abnormal overheating of the electric device 2 can be detected on the low voltage side.

As described above, the measuring device 9 targets the voltage fluctuation of the voltage dividing capacitor 5 for a voltage drop of a certain range. In addition to this, after the switching element 8 is changed to the off state due to abnormal overheating, By adding an appropriate control circuit around the switching element 8 so that the voltage dividing capacitor 7 regularly repeats short-circuiting and opening, the voltage of the voltage dividing capacitor 5 is repeatedly decreased, restored and decreased. It is also possible to cause a fluctuation due to the constant encoding of, and detect this by the measuring device 9. Further, the opening / closing element 8 is normally turned off, and may be configured to be turned on when an abnormality occurs. At this time, the voltage of the voltage dividing capacitor 5 at the time of abnormality increases. Further, the opening / closing element 8 is not limited to a contact mechanism such as a bimetal, and may be a contactless mechanism.

[0015]

As described above, according to the present invention, when detecting an abnormality in an electric device, an opening / closing element that operates in response to the occurrence of an abnormality in a high voltage portion is detected. In order to transmit the change in the state of the switching element to the low voltage side, a capacitor voltage divider type potential transformer that measures the voltage of the high voltage busbar is used, so the configuration for transmitting to the low voltage side is simplified. There is an effect that can be realized.

[Brief description of drawings]

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

[Explanation of symbols]

 1 High Voltage Bus 2 Electric Equipment 3 Capacitor Voltage Dividing Potential Transformer 4 Coupling Capacitor 5 Voltage Dividing Capacitor 6 Measuring Equipment for High Voltage Bus Voltage Measurement 7 Second Voltage Dividing Capacitor 8 Switching Elements 9 Measuring Equipment for Voltage Fluctuation Measurement

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiki Hayashi, 47 Umezu Takaune-cho, Ukyo-ku, Kyoto City, Nissin Electric Co., Ltd.

Claims (1)

[Claims] 1. A coupling capacitor and a first voltage dividing capacitor are connected in series, the series circuit is connected between a high voltage bus bar and ground, and the high voltage is spread over the first voltage dividing capacitor. A second voltage dividing capacitor is connected to a capacitor voltage dividing type potential transformer which is connected to a measuring device for measuring the voltage of the bus bar, and is connected so as to be located between the coupling capacitor and the high voltage bus bar. An electrical device in which an opening / closing element that operates when an abnormality occurs in an electrical device that is an abnormality detection target is connected across the voltage dividing capacitor, and a measuring device that further measures the voltage fluctuation is connected across the first voltage dividing capacitor. Equipment abnormality detection device.