KR101840980B1 - Diagnosis device for isolation deterioration of electric apparatus and diagnosis method thereof - Google Patents

Abstract

The present invention relates to a method for diagnosing insulation degradation of an electric device, which can diagnose insulation degradation in real time by analyzing a harmonic component and a fundamental wave component of an applied voltage and a current flowing into and/or discharged from a winding and detecting values of capacitance of a winding, inductance, resistance, interground capacitance, and interground synthetic leakage resistance. According to an embodiment of the present invention, disclosed is a method for diagnosing insulation degradation of an electric device, the method comprising: a detection step of detecting a voltage and a current flowing in a winding; an operation step of substituting the current and the voltage detected in the detection step into a degradation detection algorithm to calculate interlayer capacitance of the winding, inductance, resistance, interground synthetic capacitance, and interground synthetic leakage resistance; and a storage determination step of storing the value calculated in the calculation step in real time and determining that the winding is deteriorated if the calculated value is out of a reference range.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an insulation deterioration diagnosis apparatus,

 The present invention relates to an apparatus and method for diagnosing insulation deterioration of an electric apparatus.

Generally, electrical devices such as transformers, generators, and motors are produced by winding insulated coils around an iron core. The inductance, resistance, interlayer capacitance, and leakage resistance of the winding are present. When the insulation of the equipment deteriorates or the structure is deformed, . Also, if the value of these elements is changed beyond the reference value, the insulation breaks down and causes an accident. On the other hand, before reaching the accident, there are signs such as partial discharge (PD) or generation of gas in insulating oil. Therefore, PD diagnosis and gas analysis are used for preventive diagnosis. However, when PD is generated near the inner core of the coil, it is difficult to detect because it is absorbed into the core, and it takes a long time until the gas is absorbed and detected by the insulating oil.

The present invention analyzes the fundamental wave component and the harmonic component of a current flowing into and / or out of a winding and a voltage applied thereto, and detects a value of capacitance, inductance, resistance, ground capacitance, and leakage resistance between ground The present invention provides an apparatus and method for diagnosing an insulation deterioration of an electric device capable of diagnosing insulation deterioration in real time.

According to another aspect of the present invention, there is provided a method of diagnosing an electrical deterioration of an electric device, comprising: detecting a current and a voltage flowing in a winding; Calculating an inter-layer capacitance, an inductance, a resistance, a ground-to-ground composite capacitance, and a ground-to-ground composite leakage resistance by substituting the current and voltage detected in the detection step into a deterioration detection algorithm; And a storage determining step of storing the values calculated in the calculating step in real time and determining that the winding is deteriorated when each calculated value is out of a reference range.

Wherein the electric machine has a primary winding or a secondary winding, and the inductance (L ₁ ) of the primary winding is calculated by the following equation,

The resistance (R ₁ ) of the primary winding is calculated by the following equation,

The interlayer capacitance (C ₁ ) of the primary winding is calculated by the following equation,

here,

이고,

ego,

Y ₁₁ is the primary wave primary winding admittance, and Y ₁₃ is the tertiary primary winding admittance.

The fundamental wave primary winding admittance (Y ₁₁ ) is calculated by the following equation,

The third harmonic primary winding admittance (Y ₁₃ ) is calculated by the following equation,

Here, I ₀₁₁ is the fundamental wave a primary excitation current, θI ₀₁₁ is phase angle of the I _011, E ₁₁ is the phase angle of the fundamental primary winding voltage, θE ₁₁ is E _11, I ₀₁₃ 3 Sowing primary excitation current, θI is the phase angle _013, the E ₁₃ I ₀₁₃ 3 Sowing the primary winding voltage, θE ₁₃ may represent a phase angle E of _13.

The composite leakage resistance Rg ₁ between the primary windings is calculated by the following equation,

The ground-to-ground composite capacitance (Cg ₁ ) of the primary winding is calculated by the following equation,

Here, Yg ₁₁ may be a fundamental wave a primary winding leakage admittance.

The inductance (L ₂ ) of the secondary winding is calculated by the following equation,

The resistance (R ₂ ) of the secondary winding is calculated by the following equation,

The interlayer capacitance (C ₂ ) of the secondary winding is calculated by the following equation,

here,

이고,

ego,

Y ₂₁ is the fundamental wave secondary winding admittance, and Y ₂₃ is the tertiary secondary winding admittance.

The fundamental wave secondary winding admittance (Y ₂₁ ) is calculated by the following equation,

The third harmonic secondary winding admittance (Y ₂₃ ) is calculated by the following equation,

Here, I ₀₂₁ is the fundamental wave secondary side excitation current, θI ₀₂₁ is phase angle of the I _021, E ₂₁ is a fundamental wave secondary winding voltage, θE ₂₁ is the phase angle, I ₀₂₃ of the E ₂₁ 3 Sowing secondary side excitation current, θI ₀₂₃ has a phase angle of ₀₂₃ I, ₂₃ E 3 Sowing secondary winding voltage, θE ₂₃ may represent a phase angle E of _23.

The combined leakage resistance Rg ₂ between the secondary windings is calculated by the following equation,

The ground-to-ground composite capacitance (Cg ₂ ) of the secondary winding is calculated by the following equation,

Here, Yg ₂₁ may be the fundamental wave secondary winding leakage admittance.

Wherein the electric device is provided with both of the primary winding and the secondary winding when the electric device is a transformer, and in the calculating step, the interlayer capacitance, inductance, resistance, interground mass composite capacitance and interground earth combined leakage resistance of the primary winding, The deterioration can be determined by calculating the interlayer capacitance, inductance, resistance, ground capacitance, and ground leakage resistance of the secondary winding.

Wherein when the electric device is a shunt reactor, the fundamental wave primary _exciting current (I ₀₁₁ ) is changed to the fundamental wave primary winding output current (I ₁₁ ), and the triple wave primary electromotive _force current (I ₀₁₃ ) (I ₁₃ ) of the primary winding.

In the case where the electric device is a motor, in the calculating step, the deterioration can be determined by calculating the composite leakage resistance Rg ₁ and the intergrounding composite capacitance Cg ₁ of the primary winding.

In the case where the electric device is a generator, in the calculating step, deterioration can be determined by calculating the composite leakage resistance Rg ₂ and the intergrounding composite capacitance Cg ₂ of the secondary winding.

The apparatus for diagnosing an electric deterioration of an electric device according to an embodiment of the present invention analyzes a fundamental wave component and a harmonic component of an electric current flowing into and / or out of a coil and a voltage applied thereto and determines the capacitance, inductance, resistance, It is possible to detect the leakage resistance value of the composite capacitance and the earth leakage current, and thereby to detect the deterioration of the winding in real time. Accordingly, the apparatus for diagnosing an electric deterioration of an electric device according to the present invention can reduce deterioration measurement time and cost, and can improve the safety of the electric device.

1 is a block diagram showing an apparatus for diagnosing an electrical deterioration of an electric device according to an embodiment of the present invention.
FIG. 2A is a diagram showing an equivalent circuit of a transformer in an electric machine, and FIG. 2B is a diagram showing a more simplified equivalent circuit in FIG. 2A.
3 is a circuit diagram showing a state for measuring the insulation deterioration of the secondary winding of the transformer in the electric equipment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

1 is a block diagram showing an apparatus for diagnosing an electrical deterioration of an electric device according to an embodiment of the present invention.

Referring to FIG. 1, an apparatus for diagnosing an electrical deterioration of an electric apparatus 100 according to an embodiment of the present invention includes a detecting unit 110, an operation unit 120, a storage determination unit 140, and a signal output unit 150 do. Here, the electric device refers to an electric device that is made by winding an insulated coil on an iron core, that is, having an electric wire. Specifically, the electric device may include a transformer, a generator, a motor, a shunt reactor or an electric motor.

The detection unit 110 detects in real time the current flowing into and / or outflow from the windings and the applied voltage in the electric device for diagnosing deterioration. The current and voltage detected by the detecting unit 110 are transmitted to the calculating unit 120. Here, the detector may measure a current flowing in and / or out of the winding and a voltage applied thereto using a separate measuring device, but the present invention is not limited thereto.

The operation unit 120 analyzes the fundamental wave component and the harmonic wave component of the current and voltage detected by the detection unit 110. Meanwhile, in the present invention, the deterioration is detected by analyzing the third harmonic component of the harmonic components. However, the harmonic components may be harmonics of any order such as 5th, 7th and 9th harmonics. Specifically, the calculation unit 120 substitutes the detected current and voltage for the deterioration detection algorithm to calculate the values of the interlayer capacitance, inductance, resistance, inter-site composite capacitance, and inter-site composite leakage resistance of the winding. The degradation detection algorithm includes a primary winding algorithm and a secondary winding algorithm. This is because the electric device having the windings may have only the primary side or the secondary side windings, or both the primary side and the secondary side windings, so that different algorithms can be used depending on the winding state of the applied electric device. The degradation detection algorithm will be described in more detail below.

The storage determination unit 130 stores in real time the values of the capacitance, inductance, resistance, inter-site composite capacitance, and inter-site composite leakage resistance calculated in the calculation unit 120 and analyzes the stored values, . Specifically, the storage determination unit 130 may determine that deterioration has occurred if the measured capacitance, inductance, resistance, inter-site composite capacitance, and ground-to-ground combined leakage resistance values are out of the reference range. Here, the storage determination unit 130 preliminarily stores the values of the capacitance, inductance, resistance, ground capacitance, and the reference range of the ground leakage resistance.

The signal output unit 140 outputs a signal according to the determination result of the storage determination unit 130. For example, the signal output unit 140 determines that any one of the capacitance, inductance, resistance, inter-site composite capacitance, and ground-to-ground composite leakage resistance of the winding is out of the reference range in the storage determination unit 130 An alarm can be generated.

Next, a method for diagnosing deterioration of a transformer of an electric deterioration diagnosis apparatus for an electric device according to an embodiment of the present invention will be described.

FIG. 2A is a diagram showing an equivalent circuit of a transformer in an electric machine, and FIG. 2B is a diagram showing a more simplified equivalent circuit in FIG. 2A.

As shown in Figs. 2A and 2B, the transformer includes a primary winding and a secondary winding. Therefore, in the apparatus for diagnosing an electrical deterioration of an electric apparatus 100 according to the present invention, the calculating unit 120 applies a primary winding algorithm to measure the insulation deterioration of the primary winding of the transformer, Apply a secondary winding algorithm to measure degradation.

First, in Fig. 2b E ₁₁ is the fundamental primary winding voltage, C ₁ is the primary winding interlayer capacitance, R ₁ is the primary winding resistance, L ₁ is the primary winding inductance, I _'11 is the fundamental primary winding flows current, I ₁₁ denotes a fundamental wave a primary winding leakage current, Ig ₁₁ is the fundamental primary composite capacitance between wires between grounds leakage current, Rg ₁ is the primary composite leakage between wires ground resistance, Cg ₁ is the primary winding Property . In addition, E ₂₁ is a fundamental wave secondary winding voltage, C ₂ is the secondary winding interlayer capacitance, R ₂ is a secondary winding resistance, L ₂ is a secondary winding inductance, I _'21 is the fundamental wave secondary winding leakage current, I ₂₁ is the fundamental wave secondary winding current, Ig ₂₁ is the fundamental wave secondary winding earth leakage current, Rg ₂ is the composite leakage resistance between the secondary windings, and Cg ₂ is the composite capacitance between the secondary windings.

The primary winding algorithm is calculated in the order of the following equations (1) to (13), and finally the inductance L1 of the primary winding, the resistance R1, the interlayer capacitance C1, And the ground-to-ground composite capacitance (Cg1).

Wherein, Y ₁₁ is the phase angle of the fundamental primary winding admittance, I ₀₁₁ is the fundamental wave a primary excitation current, θI ₀₁₁ is phase angle of the I _011, E ₁₁ is the fundamental primary winding voltage, θE ₁₁ is E ₁₁ . Further, I ₀₁₁ = I ₁₁ -I ₂₁ can be obtained.

Wherein, Y ₁₃ is a three-wave primary winding admittance, I ₀₁₃ 3 Sowing primary excitation current, θI ₀₁₃ is the phase angle, E ₁₃ of I ₀₁₃ 3 Sowing the primary winding voltage, θE ₁₃ is a phase angle E ₁₃ . Further, I ₀₁₃ = I ₁₃ -I ₂₃ can be obtained. Where I ₁₃ is the third harmonic primary winding out current and I ₂₃ is the third harmonic secondary winding inrush current.

From Equation (2) and Equation (5), the following Equation (7) can be obtained.

here,

to be.

Further, the following equations (8) and (9) can be obtained from the equations (3) and (6).

From Equation (8) and Equation (9), the following Equation (10) can be obtained.

Substituting Equation (7) into Equation (10) results in the following.

Therefore, the inductance (L ₁ ) of the primary winding is as follows.

By substituting the value of L ₁ into the expression (7), the resistance (R ₁ ) of the primary winding can be obtained.

In addition, by substituting the values of L ₁ and R ₁ into the equation (8), the interlayer capacitance (C ₁ ) of the primary winding can be obtained.

Here, Yg ₁₁ is a fundamental wave a primary winding leakage admittance, Ig ₁₁ is the phase angle between the fundamental primary winding earth leakage current, θIg ₁₁ is Ig _11, E ₁₁ is the fundamental primary winding voltage, θE ₁₁ is E ₁₁ Respectively. In addition, Ig ₁₁ = I _'11 - can be determined as I _11.

From the above equation (12), the composite leakage resistance Rg ₁ between the primary windings can be obtained.

Also, the composite capacitance Cg ₁ between the primary windings can be obtained from Equation (13).

Next, Fig. 3 is a circuit diagram showing a state for measuring the insulation deterioration of the secondary winding of the transformer in the electric equipment.

The secondary winding algorithm is calculated in the order of the following equations (14) to (22), and finally the inductance L ₂ , the resistance R ₂ , the interlayer capacitance C ₂ , (Rg ₂ ) and ground-to-ground composite capacitance (Cg ₂ ). Here, when the inductance (L ₂ ), the resistance (R ₂ ) and the interlayer capacitance (C ₂ ) associated with the interlayer deterioration of the secondary winding are measured, it is difficult to detect the state when power is supplied from the primary side. As shown, the circuit breaker on the primary side is opened and power is supplied from the secondary side to measure. Also, when measuring the combined leakage resistance (Rg ₂ ) and ground-to-ground composite capacitance (Cg ₂ ) associated with deterioration of the ground between secondary windings, it is possible to monitor at all times in the primary power supply state.

Wherein, Y ₂₁ is the phase angle of the fundamental wave secondary winding admittance, I ₀₂₁ is the fundamental wave secondary side excitation current, θI ₀₂₁ is phase angle of the I _021, E ₂₁ is a fundamental wave secondary winding voltage, θE ₂₁ is E ₂₁ . Further, I ₀₂₁ = I ₂₁ - I ₁₁ can be obtained.

Wherein, Y ₂₃ is a three-wave secondary winding admittance, I ₀₂₃ 3 Sowing secondary side excitation current, θI ₀₂₃ is phase angle of the I _023, E ₂₃ is a three-wave secondary winding voltage, θE ₂₃ is a phase angle E ₂₃ . Further, I ₀₂₃ = I ₂₃ - I ₁₃ can be obtained.

In addition, the inductance (L ₂ ), the resistance (R ₂ ), and the interlayer capacitance (C ₂ ) of the secondary winding are obtained from the equations (14) to (19) through the same calculation process as the primary winding algorithm .

Here, Yg ₂₁ is a fundamental wave secondary winding leakage admittance, Ig ₂₁ is a fundamental wave secondary winding between grounds leakage current, θIg ₂₁ is the phase angle of the Ig _21, E ₂₁ is a fundamental wave secondary winding voltage, θE ₂₁ is E ₂₁ Respectively. In addition, Ig ₂₁ = I ₂₁ - I 'can be found in _21.

From the above equation (21), the composite leakage resistance Rg ₂ between the secondary windings can be obtained.

Further, the composite capacitance (Cg ₂ ) between the secondary windings can be obtained from Equation (22).

In addition, the deterioration diagnosis apparatus for electrical equipment according to an embodiment of the present invention can measure deterioration of shunt reactors, motors, and generators in addition to a transformer.

For example, in measuring the deterioration of the shunt reactor, the primary winding algorithm is used in the same manner, but in the above equation, I ₀₁₁ is changed to I ₁₁ , and I ₀₁₃ is changed to I ₁₃ .

In addition, since rotors such as motors and generators have a deterioration in intergranular deterioration rather than interlayer deterioration unlike transformers, the degree of deterioration can be measured by applying only the portions related to intergranular deterioration in the primary winding algorithm and the secondary winding algorithm have.

In measuring the deterioration between the ground of the motor, the composite leakage resistance between the ground and the inter-site composite capacitance of the motor can be obtained by applying Equations (11) to (13) in the primary winding algorithm.

Further, when measuring the deterioration of the generator, the combined leakage resistance and ground-to-ground combined capacitance of the generator can be obtained by applying Equations (20) to (22) in the secondary winding algorithm.

It is to be understood that the present invention is not limited to the above-described embodiment, but may be embodied in various forms without departing from the spirit or scope of the following claims. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

110:
120:
130:
140: Signal output section

Claims (12)

A detecting step of detecting a current and a voltage flowing in the winding;
Calculating an inter-layer capacitance, an inductance, a resistance, a ground-to-ground composite capacitance, and a ground-to-ground composite leakage resistance by substituting the current and voltage detected in the detection step into a deterioration detection algorithm; And
And a storage determining step of storing the values calculated in the calculating step in real time and judging that the winding is deteriorated when each calculated value is out of a reference range,
The electric device has a primary winding or a secondary winding,
The inductance (L ₁ ) of the primary winding is calculated by the following equation,

The resistance (R ₁ ) of the primary winding is calculated by the following equation,

The interlayer capacitance (C ₁ ) of the primary winding is calculated by the following equation,

here,

ego,
Y ₁₁ is a fundamental wave primary winding admittance, and Y ₁₃ is a tertiary wave primary winding admittance. delete The method according to claim 1,
The fundamental wave primary winding admittance (Y ₁₁ ) is calculated by the following equation,

The third harmonic primary winding admittance (Y ₁₃ ) is calculated by the following equation,

Here, I ₀₁₁ is the fundamental wave a primary excitation current, θI ₀₁₁ is phase angle of the I _011, E ₁₁ is the phase angle of the fundamental primary winding voltage, θE ₁₁ is E _11, I ₀₁₃ 3 Sowing primary excitation current, θI ₀₁₃ I is the phase angle of _013, E ₁₃ is a three-wave voltage primary winding, θE ₁₃ is isolated degradation diagnostic method of the electrical device, characterized in that represents the phase angle of the ₁₃ E. The method according to claim 1,
The composite leakage resistance Rg ₁ between the primary windings is calculated by the following equation,

The ground-to-ground composite capacitance (Cg ₁ ) of the primary winding is calculated by the following equation,

Here, Yg ₁₁ is a fundamental wave primary winding leakage admittance. The method according to claim 1,
The inductance (L ₂ ) of the secondary winding is calculated by the following equation,

The resistance (R ₂ ) of the secondary winding is calculated by the following equation,

The interlayer capacitance (C ₂ ) of the secondary winding is calculated by the following equation,

here,

Y ₂₁ is a fundamental wave secondary winding admittance, and Y ₂₃ is a tertiary wave secondary winding admittance. 6. The method of claim 5,
The fundamental wave secondary winding admittance (Y ₂₁ ) is calculated by the following equation,

The third harmonic secondary winding admittance (Y ₂₃ ) is calculated by the following equation,

Here, I ₀₂₁ is the fundamental wave secondary side excitation current, θI ₀₂₁ is phase angle of the I _021, E ₂₁ is a fundamental wave secondary winding voltage, θE ₂₁ is the phase angle, I ₀₂₃ of the E ₂₁ 3 Sowing secondary side excitation current, θI is the phase angle _023, the E ₂₃ I ₀₂₃ 3 Sowing secondary winding voltage, θE ₂₃ is isolated degradation diagnostic method of the electrical device, characterized in that represents the phase angle of the ₂₃ E. The method according to claim 1,
The combined leakage resistance Rg ₂ between the secondary windings is calculated by the following equation,

The ground-to-ground composite capacitance (Cg ₂ ) of the secondary winding is calculated by the following equation,

Wherein Yg ₂₁ is a fundamental wave secondary winding leakage admittance. The method according to claim 1,
Wherein the electric device is provided with both of the primary winding and the secondary winding when the electric device is a transformer, and in the calculating step, the interlayer capacitance, inductance, resistance, interground mass composite capacitance and interground earth combined leakage resistance of the primary winding, Wherein the deterioration is determined by calculating the interlayer capacitance, inductance, resistance, ground capacitance, and ground leakage resistance of the secondary winding. The method of claim 3,
Wherein when the electric device is a shunt reactor, the fundamental wave primary _exciting current (I ₀₁₁ ) is changed to the fundamental wave primary winding output current (I ₁₁ ), and the triple wave primary electromotive _force current (I ₀₁₃ ) the primary winding current flows insulation degradation diagnosis method of the electrical device, characterized in that the application by changing the (I _13). 5. The method of claim 4,
If the electrical machine is a motor, the insulation in the operating step electric machine, characterized in that for determining the deterioration by calculating the composite capacitance (Cg ₁₎ to ground between the composite leakage resistance (Rg ₁₎ and the premises of the primary winding Deterioration diagnostic method. 8. The method of claim 7,
Wherein when the electric device is a generator, the calculating step determines the deterioration by calculating a combined leakage resistance (Rg ₂ ) and an intergrounding composite capacitance (Cg ₂ ) of the secondary winding of the secondary winding Deterioration diagnostic method. An apparatus for diagnosing an electrical deterioration of an electric device, characterized by diagnosing the deterioration of electrical equipment by the diagnostic method according to any one of claims 1 to 11.

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