JP2020159691A - Insulation state monitoring device - Google Patents

Abstract

To provide an insulation state monitoring device that monitors an insulation state of electrical equipment in the horizontal and vertical directions.SOLUTION: Based on a first AC voltage V1 and current I1, total impedance Z, total insulation resistance R, and total capacitance C between a horizontal electrode 1 and a vertical electrode 2 are calculated. Based on a third voltage V3 between the horizontal electrode 1 and a common electrode 3, a fourth voltage V4 between the vertical electrode 2 and the common electrode 3, a voltage difference ΔV between the third voltage V3 and the fourth voltage V4, and the total impedance Z, an insulation resistance RH and a static capacitance CH between the horizontal electrode 1 and the common electrode 3, and an insulation resistance RV and a static capacitance CV between the vertical electrode 2 and the common electrode 3 are obtained.SELECTED DRAWING: Figure 1

Description

The present invention relates to an insulation state monitoring device for diagnosing deterioration of the insulation state of an electric device in an electric facility, and more particularly to a device for diagnosing deterioration of the insulation state in the horizontal and vertical directions of the electric device.

In electrical equipment such as cubicles, switchboards, and factories, if dust or the like accumulates on the electrical equipment in the electrical equipment, the insulation state of the electrical equipment deteriorates, and in the worst case, a fire or the like may occur. Therefore, conventionally, the insulation of electrical equipment is maintained by regularly cleaning and maintaining the electrical equipment.

Japanese Unexamined Patent Publication No. 2015-162320 Japanese Unexamined Patent Publication No. 8-210890

However, since it is unclear how much dust is accumulated in what period and how much dust is accumulated to cause deterioration of insulation, it is not possible to improve the efficiency of maintainability.

In addition, the amount of dust and the like accumulated on electrical equipment varies depending on the location, season, wind direction, and the like. When cleaning and maintaining electrical equipment on a regular basis, the maintenance schedule is generally set assuming a situation with a lot of dust, so the interval between cleaning and maintenance is shortened, and the number of cleanings and maintenance is reduced. More.

In addition, some electric devices have a three-dimensional structure, and dust may accumulate not only in the horizontal direction of the electric device but also in the vertical direction of the electric device depending on the environment such as the wind direction.

From the above, it is an issue to monitor the insulation state of the electric device in the horizontal direction and the vertical direction in the insulation state monitoring device.

The present invention has been devised in view of the above-mentioned conventional problems, and one aspect thereof is a horizontal plane electrode, a vertical plane electrode provided substantially perpendicular to the horizontal plane electrode, and substantially parallel to the horizontal plane electrode. A common electrode having a first electrode arranged at a predetermined distance and a second electrode arranged at a predetermined distance substantially parallel to the vertical plane electrode, one end of the horizontal plane electrode and one end of the vertical plane electrode. A first voltage generating means capable of generating a first AC voltage between a connection point connecting one end of the common electrode and the common electrode and automatically adjusting the voltage according to an insulation state, the horizontal plane electrode and the above. To the second voltage generating means for generating a second AC voltage having a frequency different from the first AC voltage between the vertical plane electrodes, the first AC voltage, and the current flowing between the common electrode and the connection point. Based on this, the total impedance Z, the total insulation resistance, and the total capacitance between the horizontal plane electrode and the vertical plane electrode are calculated, and the third voltage between the horizontal plane electrode and the common electrode, and the vertical plane electrode and the above. Based on the fourth voltage between the common electrodes, the voltage difference between the third voltage and the fourth voltage, and the total impedance, the insulation resistance and capacitance between the horizontal plane electrode and the common electrode, and It is characterized by including an arithmetic unit for obtaining the insulation resistance and capacitance between the vertical plane electrode and the common electrode.

According to the present invention, it is possible to monitor the insulation state of an electric device in the horizontal direction and the vertical direction in the insulation state monitoring device.

The schematic diagram which shows the insulation state monitoring apparatus in embodiment. Equivalent circuit showing a relation of V1, V _Z. V1, Vr, vector diagram representing the relationship between V _Z, I1. V _Z, vector diagram representing the relationship between I _R, I1, I _C. An equivalent circuit that represents the relationship between V2, V3, and V4. The vector figure which shows the relationship of V2, V3, V4, ΔV. The vector figure which shows the relationship of V3, I3, Z. The vector diagram which shows the relationship of V4, I4, Z.

Hereinafter, embodiments of the insulation state monitoring device according to the present invention will be described in detail with reference to FIGS. 1 to 8.

[Embodiment]
First, the configuration of the insulation state monitoring device in the present embodiment will be described with reference to the schematic diagram of FIG. The insulation condition monitoring device in this embodiment shall be installed in the electrical equipment. As shown in FIG. 1, the insulation state monitoring device includes a horizontal plane electrode 1, a vertical plane electrode 2, and a common electrode 3.

The horizontal electrode 1 is provided substantially parallel to the ground. The vertical surface electrode 2 is provided with an angle difference of about 90 ° (approximately right angle) with respect to the horizontal surface electrode 1. The common electrode 3 has a first electrode 3a arranged substantially parallel to the horizontal plane electrode 1 at a predetermined distance, and a second electrode 3b arranged substantially parallel to the vertical plane electrode 2 at a predetermined distance. ..

FIG. 1 shows a horizontal surface electrode 1, a vertical surface electrode 2, and a common electrode 3 having a predetermined shape. However, the horizontal surface electrode 1 and the vertical surface electrode 2 have an angle difference of about 90 °, and the common electrode 3 has an angle difference of about 90 °. If the first electrode 3a arranged substantially parallel to the horizontal plane electrode 1 at a predetermined distance and the second electrode 3b arranged substantially parallel to the vertical plane electrode 2 at a predetermined distance are provided. Other shapes may be used.

In the present embodiment, the horizontal plane electrode 1, the vertical plane electrode 2, and the common electrode 3 are formed by a pattern (copper foil or the like) on the printed substrate, but the horizontal plane electrode 1, the vertical plane electrode 2, and the like are made of other materials. The common electrode 3 may be configured.

One end of the horizontal plane electrode 1, one end of the vertical plane electrode 2 and one end of the common electrode 3 are connected to each other. In the present embodiment, one end of the horizontal electrode 1 and one end of the vertical electrode 2 are connected via the secondary side of the transformer Tr, which will be described later. One end of the common electrode 3 is connected to the neutral point on the secondary side of the transformer Tr.

A first voltage generating means 4 for generating a first AC voltage V1 is provided between the common electrode 3 and the neutral point (the connection point) on the secondary side of the transformer Tr. A filter 5, an amplifier circuit 6, and resistors r and r1 are provided between the first voltage generating means 4 and the common electrode 3 and the neutral point on the secondary side of the transformer Tr. Since the first voltage generating means 4 measures the insulation resistance between the common electrode 3, the horizontal electrode 1, and the vertical electrode 2, the voltage can be automatically adjusted according to the insulation state.

A second voltage generating means 7 for generating a second AC voltage V2 is provided between the horizontal surface electrode 1 and the vertical plane electrode 2 via a transformer Tr. The second AC voltage V2 has a frequency f2 different from the frequency f1 of the first AC voltage V1. Further, fuses 8a and 8b may be provided between the secondary side of the transformer Tr and the horizontal electrode 1 and the vertical electrode 2 as shown in FIG.

The current detecting means 9 detects the current I1 between the connection point and the common electrode 3. The value of the current I1 varies depending on the state of insulation between the horizontal electrode 1 and the vertical electrode 2 and the common electrode 3. The current I1 detected by the current detecting means 9 is output to the arithmetic unit 13 via the filter 10, the amplifier circuit 11, and the A / D converter 12.

Due to the second AC voltage V2, the third voltage V3 is applied between the horizontal plane electrode 1 and the common electrode 3, and the fourth voltage V4 is applied between the vertical plane electrode 2 and the common electrode 3. The voltage detecting means 14 detects the third voltage V3 and the fourth voltage V4, and calculates the voltage difference ΔV between the third voltage V3 and the fourth voltage V4. The third voltage V3, the fourth voltage V4, and the voltage difference ΔV detected by the voltage detecting means 14 are output to the arithmetic unit 13 via the filter 15, the amplification circuit 16, and the A / D converter 12.

The arithmetic unit 13 calculates the total impedance Z, the total insulation resistance R, and the total capacitance C between the horizontal plane electrode 1 and the vertical plane electrode 2 from the first AC voltage V1 and the current I1 by the calculation formula A. Further, the arithmetic unit 13 has an insulation resistance R _H and a capacitance C _H between the horizontal electrode 1 and the common electrode 3 based on the third voltage V3, the fourth voltage V4, the voltage difference ΔV, and the total impedance Z, and The insulation resistance R _V and the capacitance C _V between the vertical surface electrode 2 and the common electrode 3 are calculated by the calculation formula B.

The display means 17 displays the insulation resistance R _H and the capacitance C _H , the insulation resistance R _V and the capacitance C _V calculated by the calculation formula B in the arithmetic unit 13.

The alarm means 18 compares the insulation resistance R _H and the capacitance C _H , the insulation resistance R _V and the capacitance C _V with a predetermined threshold value set in advance, and when each of the above values becomes equal to or less than the threshold value. , Display or sound alarm.

Next, an arithmetic expression A for obtaining the total impedance Z, the total insulation resistance R, and the total capacitance C between the horizontal plane electrode 1 and the vertical plane electrode 2 will be described. FIG. 2 is an equivalent circuit showing the relationship between the first AC voltage V1 and the voltage V _Z applied to the total impedance Z. In FIG. 2, the insulation resistance between the horizontal electrode 1 and the common electrode 3 is _RH , the capacitance is C _H , the insulation resistance between the vertical electrode 2 and the common electrode 3 is R _V , and the capacitance is C _V. To do. Further, the voltage generated across the resistor r between the connection point and the common electrode 3 is Vr, the current is I1, and the voltage applied to the total impedance Z is V _Z. Further, the frequency of the first AC voltage V1 is f1.

As shown in FIG. 2, the total impedance Z between the horizontal surface electrode 1 and the vertical surface electrode 2 is a value obtained by synthesizing the total insulation resistance R and the total capacitance C of the horizontal surface electrode 1 and the vertical surface electrode 2 in parallel. The voltage V _Z applied to the total impedance Z is given by the following equation (1) from the first AC voltage V1 and the current I1 flowing through the total impedance Z.

The total impedance Z is changed from the current I1 flowing through the total impedance Z by the first AC voltage V1 and the equation (1) to the following equation (2).

FIG. 3 is a diagram showing the first AC voltage V1, the voltage drop Vr, the voltage V _Z applied to the total impedance Z, and the current I1 as vectors. The phase difference between the first AC voltage V1 and the drop voltage Vr is θr, the phase difference between the first AC voltage V1 and the voltage V _Z applied to the total impedance Z is θz, and the phase difference between the voltage V _Z applied to the total impedance _Z and the current I1. Assuming that the phase difference is θ1, the phase difference θ1 is given by the following equation (3).

Based on the total impedance Z and the above equation (3), the total insulation resistance R and the total capacitance C are the following equations (4).

Figure 4 is a diagram showing currents I1, overall insulation resistance current flowing through the R I _R, Comprehensive capacitance current flowing through the C I _C, the voltage V _Z according to total impedance Z as a vector. When θ1 a phase difference between current I _R and the current I1, a current I _R, the current I _C the following equation (5).

Using current I _R, the current I _C, overall insulation resistance R, a comprehensive electrostatic capacitance C is represented as the following equation (6).

Since the total impedance Z is a value obtained by synthesizing the total insulation resistance R and the total capacitance C in parallel, it is given by the following equation (7).

Next, an operation for obtaining the insulation resistance R _H and the capacitance C _H between the horizontal electrode 1 and the common electrode 3 and the insulation resistance R _V and the capacitance C _V between the vertical surface electrode 2 and the common electrode 3 Equation B will be described.

FIG. 5 is an equivalent circuit showing the relationship between the second AC voltage V2, the third voltage V3, and the fourth voltage V4. The second AC voltage V2 has a frequency f2 and is divided into V2 / 2 and V2 / 2 at the neutral point on the secondary side of the transformer Tr. Horizon in FIG. 5 indicates the side connected to the horizontal electrode 1, and Vertical indicates the side connected to the vertical electrode 2. The voltage between the horizontal plane electrode 1 (Horizon) and the common electrode 3 (Common) is V3, and the voltage between the vertical plane electrode 2 (Vertical) and the common electrode 3 (Common) is V4. _Let Z _H be the impedance between the horizontal surface electrode 1 and the common electrode 3, and let Z _V be the impedance between the vertical plane electrode 2 and the common electrode 3. The current flowing between the horizontal surface electrode 1 and the common electrode 3 is I3, and the current flowing between the vertical plane electrode 2 and the common electrode 3 is I4. Let r be the resistance between the neutral point (connection point) on the secondary side of the transformer Tr and the common electrode 3, and let Ir be the current flowing through the resistance r. Let the voltage difference between the third voltage V3 and the fourth voltage V4 be ΔV.

As shown in FIG. 5, which represents an equivalent circuit, the current Ir flowing into the common electrode 3 (Common) is given by the following equation (8).

When the above equation (8) is rewritten using Ir = ΔV / r, I3 = V3 / Z _H , I4 = V4 / Z _V , the following equation (9) is obtained.

The combined impedance is given by the following equation (10).

Next, the impedance Z _H between the horizontal surface electrode 1 and the common electrode 3 and the impedance Z _V between the vertical plane electrode 2 and the common electrode 3 are obtained. First, the relationship between the second AC voltage V2, the third voltage V3, and the fourth voltage V4 is given by the following equation (11).

Since the potential difference ΔV = V3 + V4, V3 = V4 + ΔV and V4 = V3-ΔV. Substituting this into equation (11) gives equation (12) below.

From the above equations (9), (10), and (11), the impedance Z _H between the horizontal electrode 1 and the common electrode 3 and the impedance Z _V between the vertical surface electrode 2 and the common electrode 3 are the following equations (13). It becomes.

Next, the real part V3re, the imaginary part V3im, the phase θ3 of the third voltage V3, the real part V4re, the imaginary part V4im, and the phase θ4 of the fourth voltage V4 are obtained. FIG. 6 is a vector diagram showing the relationship between the second AC voltage V2, the third voltage V3, the fourth voltage V4, and the voltage difference ΔV. The phase difference between the second AC voltage V2 and the third voltage V3 is θ3, the phase difference between the second AC voltage V2 and the fourth voltage V4 is θ4, and the phase difference between the second AC voltage V2 and the voltage difference ΔV is Δθ. To do. The real part V3re, the imaginary part V3im, the phase difference θ3 of the third voltage V3, the real part V4re, the imaginary part V4im, and the phase difference θ4 of the fourth voltage V4 are given by the following equation (14). The subscript re indicates the size of the real part of the vector, and im indicates the size of the imaginary part. In FIG. 6, the horizontal axis is re and the vertical axis is im.

FIG. 7 is a vector diagram showing the third voltage V3, the current I3, and the total impedance Z. Let θ3 be the phase of the third voltage V3, θz be the phase of the total impedance Z, and θ _I3 be the phase of the current I3.

FIG. 8 is a vector diagram showing the fourth voltage V4, the current I4, and the total impedance Z. Let the phase of the fourth voltage V4 be θ4, the phase of the total impedance Z be θz, and the phase of the current I4 be θ _I4 .

Assuming Z _V = 0, the current I3 is given by Eq. (15) below.

From equation (15), the phase θ _I3 is given by equation (16) below.

Then, the current I3 _R flowing in the insulation resistance component of the current I3 and the current I3 _C flowing in the capacitance component of the current I3 are given by the following equation (17).

Assuming that Z _H = 0, the current I4 is given by the following equation (18).

From the equation (18), the phase θ _I4 becomes the following equation (19).

Then, the current I4 _R flowing in the insulation resistance component of the current I4 and the current I4 _C flowing in the capacitance component of the current I4 are given by the following equation (20).

Based on the second AC voltage V2 and the above I3 _R , I3 _C , I4 _R , I4 _C , the insulation resistance R _H and capacitance C _H between the horizontal plane electrode 1 and the common electrode 3 and the vertical plane electrode 2 The insulation resistance R _V and capacitance C _V between the common electrodes 3 are obtained by the following equation (21).

As shown above, according to the insulation state monitoring device of the present embodiment, it is possible to detect the insulation state of the electric device. In addition, the insulation resistance R _H and capacitance C _H between the horizontal surface electrode 1 and the common electrode 3 and the insulation resistance R _V and capacitance C _V between the vertical surface electrode 2 and the common electrode 3 are calculated to calculate the electrical equipment. It is possible to monitor the insulation state of each electrode according to the horizontal and vertical pollution states. Some electric devices have a three-dimensional structure, and dust and the like may accumulate not only in the horizontal direction of the electric device but also in the vertical direction of the electric device depending on the environment such as the wind direction. Therefore, by simultaneously monitoring the insulation state of the electric device in the horizontal direction and the vertical direction, it is possible to accurately grasp the insulation state of the entire electric device. Further, it is not necessary to provide an insulation state monitoring device in each of the horizontal direction and the vertical direction of the electric device, and one insulation state monitoring device may be used.

In the embodiment, the case where dust is accumulated on the electric device has been described, but the present invention monitors the insulation state not only when the dust is accumulated but also when some substance adheres to the electric device and the insulation state deteriorates. It is possible.

Although the above has been described in detail only with respect to the specific examples described in the present invention, it is clear to those skilled in the art that various modifications and modifications are possible within the scope of the technical idea of the present invention. It goes without saying that such modifications and modifications fall within the scope of patent claims.

1: Horizontal electrode 2: Vertical electrode 3: Common electrode 4: First voltage generating means 5, 10, 15: Filter 6, 11, 16: Amplifier circuit 7: Second voltage generating means 8a, 8b: Fuse 9: Current Detection means 12: A / D converter 13: Arithmetic unit 14: Voltage detection means 17: Display means 18: Alarm means

Claims (3)

Horizontal electrode and
A vertical surface electrode provided at a substantially right angle to the horizontal surface electrode and
A common electrode having a first electrode arranged substantially parallel to the horizontal plane electrode at a predetermined distance and a second electrode arranged substantially parallel to the vertical plane electrode at a predetermined distance.
A first AC voltage can be generated between the connection point connecting one end of the horizontal plane electrode, one end of the vertical plane electrode, and one end of the common electrode, and the common electrode, and the voltage can be automatically adjusted according to the insulation state. The first voltage generating means and
A second voltage generating means for generating a second AC voltage having a frequency different from that of the first AC voltage between the horizontal plane electrode and the vertical plane electrode.
Based on the first AC voltage and the current flowing between the common electrode and the connection point, the total impedance, total insulation resistance, and total capacitance between the horizontal plane electrode and the vertical plane electrode are calculated, and the horizontal plane electrode is used. Based on the third voltage between the common electrode, the fourth voltage between the vertical plane electrode and the common electrode, the voltage difference between the third voltage and the fourth voltage, and the total impedance. An arithmetic unit for obtaining the insulation resistance and capacitance between the horizontal plane electrode and the common electrode, and the insulation resistance and capacitance between the vertical plane electrode and the common electrode.
An insulation condition monitoring device characterized by being equipped with. Based on the first AC voltage and the current flowing between the common electrode and the connection point, the total insulation resistance between the horizontal surface electrode and the vertical surface electrode is determined by the following equations (1) to (4). The insulation state monitoring device according to claim 1, wherein the total capacitance is calculated.

However, r: resistance between the connection point and the common electrode
V _Z : Voltage of total impedance Z
V1: First AC voltage
Vr: Voltage generated across the resistor r
I1: Current flowing between the common electrode and the connection point
θ1: Phase difference between Vz and I1
θr: Phase difference between V1 and Vr
θz: Phase difference between V1 and Vz
R: Total insulation resistance
C: Total capacitance
f1: Frequency of the first AC voltage
Z: Total impedance To the third voltage between the horizontal plane electrode and the common electrode, the fourth voltage between the vertical plane electrode and the common electrode, the voltage difference between the third voltage and the fourth voltage, and the total impedance. Based on the following equations (11), (12), (15) to (21), the insulation resistance and capacitance between the horizontal electrode and the common electrode, and the vertical electrode and the above. The insulation state monitoring device according to claim 1 or 2, wherein the insulation resistance and capacitance between the common electrodes are obtained.

Assuming Z _V = 0

Assuming Z _H = 0

However, I3: Current flowing between the horizontal electrode and the common electrode
I4: Current flowing between the vertical plane electrode and the common electrode
V2: 2nd AC voltage
V3: Voltage between the horizontal electrode and the common electrode
V4: Voltage between vertical plane electrode and common electrode
ΔV: Voltage difference between V3 and V4
r: Resistance between the connection point and the common electrode
Z _H : Impedance between the horizontal electrode and the common electrode
Z _V : Impedance between the vertical plane electrode and the common electrode
Z: Total impedance
θ3: Phase of V3
θ4: Phase of V4
θ _I3 : Phase of I3
θ _Z : Phase of Z
Current flowing through the insulation resistance component of I3 _R = I3
Current flowing through the capacitance component of I3 _C = I3
θ _I4 : Phase of I4
Current flowing through the insulation resistance component of I4 _R = I4
Current flowing through the capacitance component of I4 _C = I4
R _H : Insulation resistance between the horizontal electrode and the common electrode
C _H : Capacitance between the horizontal electrode and the common electrode
R _V : Insulation resistance between the vertical plane electrode and the common electrode
C _V : Capacitance between the vertical plane electrode and the common electrode
f2: Frequency of the second AC voltage

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