JPH09119958A - Insulation diagnosis device for electrical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation diagnosis device for electrical apparatus which can check from multiple viewpoints for an antenna circuit. SOLUTION: In the insulation diagnosis device for electrical apparatus with an antenna 1 for detecting the partial discharge of an electrical apparatus 5 and a diagnosis device 2 which is connected to the above antenna, a capacitor C2 is inserted in series with the above antenna and two light emitting elements D1 and D2 are connected in parallel with the capacitor in opposite polarity to each other. The light emitting elements light on or blink in response to a signal from the side of the diagnosis device 2 and displays the state of the antenna circuit. The state of the antenna circuit can be confirmed by the display on the antenna side. Also, by using the light emitting element as an impedance element, the antenna circuit can be checked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation diagnosis device for electric equipment for diagnosing insulation performance of electric equipment such as GIS and cubicles.

[0002]

2. Description of the Related Art When the insulation performance of electrical equipment deteriorates, partial discharge occurs as a precursory phenomenon before an arc flashover occurs.
By detecting this partial discharge, the insulation performance of the electric device is diagnosed. FIG. 10 shows a circuit of a conventional insulation diagnostic device for electric equipment.

In the figure, 1 is an antenna, which is an electric device 5.
Is arranged in the vicinity of or inside and detects a high frequency signal generated by partial discharge of the electric device 5. A diagnostic device 2 diagnoses the insulation performance of the electric device 5 based on the partial discharge detected by the antenna 1. A cable 3 connects the antenna 1 and the diagnostic device 2. On the antenna 1 side, a high frequency signal passing capacitor C2 is inserted in series with the antenna 1. An impedance measuring resistor R3 is connected in parallel with the capacitor C2.

On the diagnostic device 2 side, a check circuit 4 is connected to the cable 3 in order to check the antenna circuit including the antenna 1 and the cable 3. In the check circuit 4, reference numeral 41 denotes a check signal source for supplying the check signal voltage V0 to the current measuring resistor R2 and the reactors L1 and L2.
To the cable 3 via. When the check signal voltage V0 is applied from the check signal source 41, the current flowing through the antenna circuit is detected as the terminal voltage V2 of the current measuring resistor R2 and input to the determination circuit 42. The voltage applied to the antenna circuit is the voltage V between the reactors L1 and L2.
It is detected as 1 and is input to the determination circuit 42.

The determination circuit 42 calculates the impedance of the resistor R3 on the antenna side based on the voltages V1 and V2. By comparing the result of this calculation with the normal value of the resistance R3, it is determined whether or not the antenna circuit is broken or the cable is short-circuited.

[0006]

In the above-described conventional insulation diagnosis device for electric equipment, the check circuit can check only the disconnection of the antenna circuit and the short circuit of the cable, and there are few types that can be checked. On the diagnostic device 2 side, the antenna operation check can be performed and the result can be known, but on the antenna 1 side, the antenna operation check cannot be performed, and the result can be known. could not.

It is an object of the present invention to provide an insulation diagnostic device for electric equipment, which can check an antenna circuit from various viewpoints. It is another object of the present invention to provide an insulation diagnostic device for electric equipment, which enables an antenna operation check to be performed on the antenna side as well as to know the result of the antenna operation check. Is.

[0008]

In order to achieve the above-mentioned object, the present invention provides an insulation diagnosis for electric equipment, which comprises an antenna for detecting partial discharge of the electric equipment and a diagnostic device connected to the antenna. In the device, a capacitor is inserted in series with the antenna in the vicinity of the antenna, and two light emitting elements are connected in parallel with the capacitor in opposite polarities.

This light emitting element lights up or blinks in response to a signal from the diagnostic device side to display the state of the antenna circuit. On the antenna side, the state of the antenna circuit can be confirmed by this display. Further, by using this light emitting element as an impedance element, the antenna circuit can be checked.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same function in the respective drawings are designated by the same reference numerals, and redundant description will be omitted. FIG. 1 is a circuit diagram showing an embodiment of an insulation diagnosis device for electric equipment of the present invention.

In the figure, 1 is an antenna, which is an electric device 5.
A high-frequency signal due to partial discharge generated when the insulation performance of the electric device 5 is deteriorated is arranged near or inside. The antenna used in the present invention includes various antennas and electrodes. Reference numeral 2 denotes a diagnostic device, which includes a tuning amplifier, an electromagnetic wave detection device such as a spectrum analyzer, and a CPU, and detects the occurrence of partial discharge on the basis of the high-frequency signal detected by the antenna 1 to detect the insulation performance of the electric device 5. Diagnose. C1 is a DC cut capacitor connected to the input side of the diagnostic device 2.

Reference numeral 3 is a cable, which is an antenna 1 and a diagnostic device 2.
It connects the spaces. In addition, a plurality of antenna circuits including the antenna 1 and the cable 3 are provided, and the plurality of antenna circuits are connected to one diagnostic device 2 via a multiplexer or the like. In the diagnostic device 2, the plurality of antenna circuits are sequentially switched to perform diagnosis. You can do it. On the antenna 1 side, a capacitor C2 for passing a high frequency signal is connected in series with the antenna 1. Two light emitting diodes D1 and D2 are connected in antiparallel in parallel with the capacitor C2. In the following description, one light emitting diode D1 is called a positive side, and the other light emitting diode D2 is called a negative side.

On the diagnostic device 2 side, a check circuit 4 for checking the antenna circuit is connected to the cable 3. In the check circuit 4, a check signal source 41 applies a check signal voltage V0 to the cable 3 via a current measuring resistor R2 and reactors L1 and L2.
When the check signal voltage V0 is applied from the check signal source 41, the current flowing through the antenna circuit is the current measuring resistor R2.
Is detected as the terminal voltage V2 of the input signal V2 and input to the determination circuit 42. The voltage applied to the antenna circuit is the reactor L
The voltage V1 between 1 and L2 is detected, and this is also input to the determination circuit 42.

The determination circuit 42 checks the antenna circuit based on the voltages V1 and V2. This determination circuit 42
The operation of will be described later. Reactors L1 and L
The reactance value of 2 is such that the reactance value at the frequency is ≈0 for the AC check signal V0 and is infinite for the high frequency signal due to the partial discharge detected by the antenna. Is selected. When the check signal is DC, the reactor value is 0.

The operation of the check circuit 4 will be described below. (Display on the antenna side) In the circuit of FIG. 1, when a positive DC signal is input from the check signal source 41 as the check signal voltage V0, the positive light emitting diode D1 is turned on, and a negative DC signal is input. The light emitting diode D2 on the negative side is turned on. When the check circuit 4 detects an abnormality in the antenna circuit by a method described later, the light emitting diodes D1 and D2 of the antenna circuit that has detected the abnormality can be lit or blinked to call attention in the field.

Further, the positive side light emitting diode D1 is a green light emitting diode and the negative side light emitting diode D2 is a red light emitting diode, so that the normal state and the abnormal state of the antenna circuit can be distinguished on the antenna side. Can be displayed. That is, in the determination circuit 42,
When the abnormality of the antenna circuit is not detected, the check signal source 41 outputs the positive check signal to turn on the green color, and when the abnormality is detected, the check signal source 41 outputs the negative check signal to emit the red color. Turn on the light.

Further, as shown in FIGS. 2 (a) and 2 (b), by changing the connection relationship of the light emitting diodes,
Two light-emitting diodes D are used for various states of the antenna circuit.
It can be displayed by a combination of turning on and off of 1 and D2. 2A and 2B show only the circuit on the antenna 1 side. In FIGS. 2A and 2B, D3
Is a diode for antenna short circuit current bypass, D4 is a diode for bias, C3 is a capacitor for antenna short circuit detection, L3 is a high frequency blocking reactor, and D5 is a diode for positive electrode current bypass.

The light emitting diode D1 on the positive side is a capacitor C.
2 directly connected in parallel. Negative side light emitting diode D2
Is connected in parallel to the capacitor C2 including the antenna 1 in (a), and the cable 3 in (b).
, And is connected in parallel to the capacitor C2. In this circuit, when a positive check signal is applied from the check signal source 41, the positive side light emitting diode D1 is turned on, but when the cable 3 is short-circuited and when the antenna 1 is used.
Does not light when is open. Further, when the negative check signal is applied from the check signal source 41, the negative side light emitting diode D2 is turned on, but is not turned on when the antenna 1 is short-circuited and when the cable is short-circuited.

The relationship between lighting and extinguishing of the light emitting diode and the state of the antenna circuit is summarized as shown in FIG. 3, and the state of the antenna circuit is discriminated from lighting (◯) and extinguishing (x) of the light emitting diode. Will be able to. That is, when positive and negative check signals are continuously output from the check signal source 41 and both the light emitting diodes D1 and D2 are turned on if the antenna circuit is normal. Antenna 1
Is short-circuited, the light emitting diode D1 on the positive side is turned on and the light emitting diode D2 on the negative side is turned off. Cable 3
Is short-circuited, both light emitting diodes D1 and D2 are turned off. If the antenna 1 is open, the light emitting diode D1 on the positive side is turned off and the light emitting diode D2 on the negative side is turned off.
Lights up.

The state of the antenna circuit on the antenna side can be identified from the combination of turning on and off the light emitting diodes D1 and D2. (Check of Antenna Circuit) Returning to the circuit of FIG. 1, whether or not the light emitting diodes D1 and D2 are conducting can be determined by monitoring the voltage V2 across the current measuring resistor R2. Furthermore, by adding and monitoring the cable applied voltage V1 and the check signal voltage V0,
The impedance of the antenna circuit can be measured to check the antenna circuit. The principle will be described with reference to FIG.

The load curves of the light emitting diodes D1 and D2 and the current measuring resistor R2 are as shown in FIG. If the contact resistance Ra = 0 in the antenna circuit, the measured current is the specified In = V2 / R2. Contact resistance R in the antenna circuit
When a increases, the current decreases to Ia = V2 / (R2 + Ra), so it can be determined that a contact failure has occurred in the antenna circuit.

(Measurement of Temperature) As shown in FIG. 5, the characteristics of the light emitting diodes D1 and D2 in the load curve of FIG. 4 change with temperature. For example, when the current In = constant and the temperature T1 changes to T2, the cable applied voltage V1
Changes from V1 (T1) to V1 (T2). When the voltage V1 = constant, the current In is In (T1)
To In (T2). Furthermore, I = Ith≈
A value of 0 is usually called a diode forward threshold value, but this value also changes with temperature. Therefore, the temperature may be measured from changes in these values.

From these changes, the light emitting diode D1,
D2 can be used as a temperature sensor. For example, by arranging the positive side light emitting diode D1 inside the electric device 5 and arranging the negative side light emitting diode D2 outside, the temperature difference between the inside and outside of the electric device 5 can be known, and the electric device 5 It is possible to detect a heating abnormality. At this time, the light emitting diodes D1 and D2 cannot be used as a display.

Further, in this temperature measurement, as shown in FIG.
As shown in (a) and (b), the light emitting diodes D1 and D2 are
In series with the resistor R3, R such as a thermistor or a temperature sensitive resistor.
4 may be inserted and the temperature may be measured by the change in the resistance value. As described above, this resistance value can be calculated from the voltages V1 and V2 in the determination circuit of FIG. In addition,
This resistor can be inserted into only one of the light emitting diodes D1 and D2.

(Insulation of Check Circuit) As shown in FIG. 7, a transformer Tr may be inserted in the check circuit to insulate the antenna 1 from the check circuit 4. In this case, DC cannot be used as the check signal source 41. (Addition of external inspection function) As shown in FIG.
It is also possible to provide a high-frequency changeover switch SW in the vicinity of so that the simulated signal generator 7 for external inspection can be connected. In the figure, a high-frequency changeover switch SW switches and connects the antenna 1 and the external terminal 8. By connecting the simulation signal generator 7 to the external terminal 8 and transmitting a signal simulating a high frequency signal generated by partial discharge of the electric device 5 to the diagnostic device 2 via the cable 3, the cable 3 is diagnosed. The device 2 can be checked.

The high-frequency selector switch SW may be one that can be remotely controlled from the diagnostic device 2 side, but it may also be a manual one that can be operated on the antenna 1 side during inspection work. In addition, high-frequency changeover switch SW
As the plug jack, the circuit may be automatically switched when the simulated signal generator jack is inserted.

Further, what is connected to the external terminal 8 may be not only the simulated signal generator 7 but also a second antenna different from the antenna 1. The second antenna may be a noise detection antenna arranged outside the electric device 4 or a second partial discharge detection antenna arranged inside the electric device 4. further,
It is also possible to connect an intercom to the external terminal 8 so that conversation can be conducted between the antenna 1 side and the diagnostic device 2 side.

(Self-inspection operation) FIG. 9 shows an example in which a switch through an impedance is provided in the vicinity of the antenna, and the antenna circuit and the measurement system are self-inspected by turning the switch on and off. In the figure, the positive side light emitting diode D
The series circuit of the impedance Z and the switch S1 is inserted in the circuit of No. 1, and the series circuit of the impedance Z and the switch S2 is inserted in the circuit of the light emitting diode D2 on the negative side.

By turning on and off these switches S1 and S2, the impedance of the antenna circuit changes. Each impedance value at this time is measured on the check circuit side. Then, as a result of the measurement, when the specified impedance value is measured, it is determined that there is no abnormality in the antenna circuit of the corresponding channel and the measurement system, and if the measured impedance value and the specified impedance value do not match, the antenna circuit Determined to be abnormal.

Since the switches S1 and S2 are connected in series with the light emitting diodes D1 and D2, the check signal source 41 always outputs a positive check signal and a negative check signal, so that whichever switch is selected. It can be determined whether it has been turned on. Therefore, in addition to the self-check operation, it is possible to switch to the detailed diagnosis mode. The detailed diagnosis mode is a mode for making the most detailed diagnosis of some diagnosis algorithms. For example, it is conceivable to increase the monitoring frequency of the corresponding channel from 5 points to 100 points to improve the diagnosis accuracy. .

The added impedance can be provided only on one side of the positive side light emitting diode D1 and the negative side light emitting diode D2.

[0032]

According to the present invention, it is possible to obtain an insulation diagnosis device for electric equipment which can check the antenna circuit from various viewpoints. Further, according to the present invention, it is possible to obtain an insulation diagnosis device for an electric device in which the antenna operation check can be performed on the antenna side and the result of the antenna operation check can be known.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of an insulation diagnosis device for electric equipment of the present invention.

FIG. 2 is a diagram showing a modified example of connection of light emitting diodes in the circuit of FIG.

FIG. 3 is a diagram illustrating the operation of the circuit of FIG.

FIG. 4 is a load characteristic diagram of the circuit of FIG.

FIG. 5 is a load characteristic diagram of the circuit of FIG. 1 when temperature characteristics are taken into consideration.

6 is a diagram showing a modified example of connection of light emitting diodes in the circuit of FIG.

7 is a diagram showing a modification of the check circuit in the circuit of FIG.

8 is a diagram showing a circuit in which an external inspection function is added to the circuit of FIG.

9 is a diagram showing a circuit in which a self-check function is added to the circuit of FIG.

FIG. 10 is a circuit diagram of a conventional insulation diagnostic device for electric equipment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... Diagnostic device 3 ... Cable 4 ... Check circuit 41 ... Check signal source 42 ... Judgment circuit 5 ... Electrical equipment 7 ... Simulated signal generator 8 ... External terminal

Claims (2)

[Claims] 1. An insulated diagnostic device for electric equipment, comprising: an antenna for detecting partial discharge of electric equipment; and a diagnostic device connected to the antenna, wherein a capacitor is provided in series with the antenna in the vicinity of the antenna. Is inserted, and two light emitting elements are connected in parallel to the capacitor in opposite polarities to each other. 2. One or both of the light emitting elements are connected in series,
The insulation diagnosis device for electric equipment according to claim 1, wherein a resistance is connected.