KR102406425B1 - Diagnosis device for isolation deterioration of electric apparatus and diagnosis method thereof - Google Patents

Abstract

여기서, N1은 1차권선의 권선수, N2는 2차권선의 권선수, I₁₂는 1차권선 유출전류, I₂₁은 2차권선 유출전류, I_0r은 여자전류 유효분, I_0x는 여자전류 무효분, θ₀는 여자전류 역률각, V1₀는 여자회로 공급전압, X_C는 여자회로 용량성 리액턴스, X_L은 여자회로 유도성 리액턴스를 나타내는 것을 특징으로 하는 전기기기의 절연열화 진단방법을 개시한다.The present invention relates to an apparatus for diagnosing insulation deterioration of an electric device and a method for diagnosing insulation deterioration in real time.
For example, in an electric device having a primary winding and a secondary winding, a detection step of detecting a current and a voltage flowing through the windings; Calculate the values of excitation current (I ₀ ), excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) or iron loss (W ₀ ) with the current and voltage detected in the detection step arithmetic step; and a storage determination step of storing the values calculated in the calculation step in real time, respectively, and determining that the winding is deteriorated when each calculated value is out of a reference range; including, wherein the excitation current (I ₀ ) is It is calculated by the formula,

Here, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I _0r is the effective amount of excitation current, and I _0x is the excitation Insulation deterioration diagnosis method of electrical equipment, characterized in that θ ₀ is the excitation current power factor angle, V1 ₀ is the excitation circuit supply voltage, X _C is the excitation circuit capacitive reactance, and X _L is the excitation circuit inductive reactance to start

Description

TECHNICAL FIELD [0002] Diagnosis device for isolation deterioration of electric apparatus and diagnosis method thereof

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

In general, electrical equipment made by winding an insulated coil such as a transformer, generator, or electric motor around an iron core has inductance, resistance, capacitance, and leakage resistance of the windings. will change In addition, when the value of these elements is changed by more than the reference value, the insulation is broken and an accident is caused. On the other hand, since signs such as partial discharge (PD) or gas generation in insulating oil appear before an accident occurs, preventive diagnosis is being conducted through PD measurement and gas analysis. However, when PD occurs in and near the inner core of the coil, it is difficult to detect because it is absorbed into the core.

The present invention analyzes the fundamental and harmonic components of the current flowing in and/or out of the winding, detecting the values of the excitation current, resistance, inductance, capacitance, and iron loss, and diagnosing insulation deterioration in real time. A diagnostic device and method for diagnosing insulation deterioration of

A method for diagnosing insulation deterioration of an electric device according to the present invention comprises the steps of: detecting a current and a voltage flowing through a winding in an electric device having a primary winding and a secondary winding; Calculate the values of excitation current (I ₀ ), excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) or iron loss (W ₀ ) with the current and voltage detected in the detection step arithmetic step; and a storage determination step of storing the values calculated in the calculation step in real time, respectively, and determining that the winding is deteriorated when each calculated value is out of a reference range; including, wherein the excitation current (I ₀ ) is It is calculated by the formula,

Here, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I _0r is the effective amount of excitation current, and I _0x is the excitation Current ineffective, θ ₀ is the excitation current power factor angle, _V10 is the excitation circuit supply voltage, X _C is the excitation circuit capacitive reactance, and X _L is the excitation circuit inductive reactance.

In the calculation step, the Nth harmonic excitation current (I _N0 ) is calculated by the following equation,

where N is the harmonic order, the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I _N0 is the Nth harmonic excitation current, I _N0r is the effective component of the Nth harmonic excitation current, I _N0x is the invalid component of the Nth harmonic excitation current, θ _N0 is the Nth harmonic excitation current power factor angle, V1 _N0 is the Nth harmonic excitation circuit supply voltage, X _C is the excitation circuit capacity The sexual reactance, X _L , can represent the excitation circuit inductive reactance.

The iron loss (W ₀ ) is calculated by the following equation,

The excitation circuit resistance (R ₀ ) is the following equation

can be calculated by

The excitation circuit inductance (L ₀ ) is calculated by the following equation,

The excitation circuit inductive reactance (X _L ) is calculated by the following equation,

can be

The excitation circuit capacitance (C ₀ ) is calculated by the following equation,

The excitation circuit capacitive reactance (X _C ) is calculated by the following equation,

Here, I _N0x is the Nth harmonic excitation current invalid.

can be

In the calculation step, the leakage current is calculated by the following equation,

Here, I ₁₁ is the primary winding inrush current, I ₁₂ is the primary winding outflow current, I _gr is the effective leakage current component, I _gx is the leakage current invalid component, θ ₀ is the leakage current power factor angle, and the insulation resistance (R _g ) and leakage capacitance (C _g ) are expressed by the following equation

,

,

can be calculated by

In the calculation step, the dielectric loss tangent (tanδ) is calculated by the following equation,

In the storage determination step, if the dielectric loss tangent tanδ is greater than a set reference value, it may be determined that the winding is deteriorated.

In the calculation step, the dielectric loss (Wg) is calculated by the following equation,

In the storage determination step, if the dielectric loss Wg is greater than a set reference value, it may be determined that the winding is deteriorated.

If the electric device is a step-up transformer or generator, change Ig to Ig ₂ and _{V10 to V2 0 to} obtain leakage current, insulation resistance, dielectric loss tangent, dielectric loss value, and leakage capacitance,

Here, I ₂₂ may represent the secondary winding inrush current, and I ₂₁ may represent the secondary winding outflow current.

When the electric device is a step-up transformer, by substituting the following formula for the excitation current (I ₀ ),

Find the values of excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) and iron loss (W ₀ ), where I ₁₁ is the primary winding inrush current, I ₂₁ is the secondary winding outflow. current can be represented.

An apparatus and method for diagnosing insulation deterioration of an electric device according to an embodiment of the present invention analyze the fundamental and harmonic components of the current flowing in and/or flowing out of the winding to determine the excitation current, resistance, inductance, capacitance and iron loss. By detecting the value, it is possible to determine the deterioration of the winding in real time. Accordingly, the apparatus and method for diagnosing insulation deterioration of an electric device according to the present invention can reduce deterioration measurement time and cost, and improve the safety of the electric equipment.

1 is a block diagram illustrating an apparatus for diagnosing insulation deterioration of an electric device according to an embodiment of the present invention.
FIG. 2A is a circuit diagram illustrating a transformer among electric devices, and FIG. 2B is an equivalent circuit of FIG. 2A.

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

Examples of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is as follows It is not limited to an Example. Rather, these examples are provided so that this disclosure will be more thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

Also, in the drawings, the same reference numerals refer to the same elements. As used herein, the term “and/or” includes any one and all combinations of one or more of those listed items.

The terminology used herein is used to describe specific embodiments, not to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly dictates otherwise. Also, as used herein, “comprise, include” and/or “comprising, including” refer to the referenced shapes, numbers, steps, actions, members, elements, and/or groups thereof. It specifies the presence and does not exclude the presence or addition of one or more other shapes, numbers, movements, members, elements and/or groups.

In addition, the storage determination unit and/or other related devices or components according to the present invention may be implemented using any suitable hardware, firmware (eg, application specific semiconductor), software, or a suitable combination of software, firmware and hardware. have. For example, various components of the storage determination unit and/or other related devices or parts according to the present invention may be formed on one integrated circuit chip or on separate integrated circuit chips. In addition, various components of the storage determination unit may be implemented on a flexible printed circuit film, and may be formed on a tape carrier package, a printed circuit board, or the same substrate as the storage determination unit. In addition, various components of the storage determination unit, in one or more computing devices, may be processes or threads executing in one or more processors, which execute computer program instructions to perform various functions mentioned below and other functions. You can interact with the components. The computer program instructions are stored in a memory that can be executed in a computing device using a standard memory device, such as, for example, a random access memory. The computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, and the like. In addition, those skilled in the art related to the present invention will know that the functions of various computing devices are combined with each other, integrated into one computing device, or the functions of a specific computing device are one or more other computing devices without departing from the exemplary embodiments of the present invention. It should be recognized that they can be distributed among

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

Referring to FIG. 1 , an apparatus 100 for diagnosing insulation deterioration of an electric device according to an embodiment of the present invention includes a detection unit 110 , an operation unit 120 , a storage determination unit 140 , and a signal output unit 150 . can do. Here, the electric machine refers to an electric machine made by winding an insulated coil around an iron core, that is, having a winding. For example, the electric device may include a transformer, a generator, a motor, a reactor, or an electric motor. In these electrical devices, when an electrical or mechanical shock occurs, the magnitude of the leakage current and the excitation current of the winding changes, and the composition ratio of the effective/reactive current also changes. Accordingly, the present invention provides a diagnostic method and apparatus capable of predicting the degree of deterioration by monitoring it and preventing an accident.

The detection unit 110 may detect in real time a current flowing in and/or flowing out of a winding and a voltage applied to the electrical device for diagnosing deterioration. In addition, the current and voltage detected by the detection unit 110 are transmitted to the operation unit 120 . Here, the detection unit 110 may measure the current flowing into and/or flowing out of the winding and the applied voltage using a separate measuring device, but the present invention is not limited thereto.

The operation unit 120 may analyze a fundamental component and a harmonic component of the current and/or voltage detected by the detection unit 110 . In some examples, the calculator 120 may calculate values of an excitation current, resistance, inductance, capacitance, and iron loss of the winding using the detected current and/or voltage.

The storage determination unit 130 calculates the excitation current (I ₀ ) of the winding calculated by the operation unit 120 , the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ), and the iron loss. The value of (W ₀ ) may be stored in real time, and the deterioration state may be determined by analyzing the stored value. In some examples, the storage determination unit 130 is the excitation current (I ₀ ) of the winding, the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ) and the iron loss (W ₀ ) of If the value is out of the reference range, it may be determined that deterioration has occurred. Here, the values for the reference ranges of the excitation current (I ₀ ) of the winding, the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ) and the iron loss (W ₀ ) are stored in the storage decision unit (130) is stored in advance.

The signal output unit 140 may output a signal according to the determination result of the storage determination unit 130 . In some examples, the signal output unit 140 is the storage determination unit 130 excitation current (I ₀ ), excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) or If it is determined that any one of the values of the iron loss W ₀ is out of the reference range, an alarm may be generated and the user may be informed.

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

FIG. 2A is a circuit diagram illustrating a transformer among electric devices, and FIG. 2B is an equivalent circuit of FIG. 2A. Here, FIG. 2B is an equivalent circuit illustrating a case where the number of turns of the primary winding and the secondary winding is the same (N1 = N2). In addition, the transformer shown in FIG. 2b will be described as a step-down transformer (V1>V2) as an example. In some examples, the electric device shown in FIG. 2B may be equally applied to, for example, a reactor or an electric motor when V1>V2.

2A and 2B, the transformer includes a primary winding and a secondary winding. The apparatus 100 for diagnosing insulation deterioration of electrical equipment according to the present invention is the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), and the excitation circuit capacitance (C ₀ ) according to the change in the excitation current (I ₀ ) value. It is possible to diagnose insulation deterioration of an electronic device by detecting changes in the value and the iron loss (W ₀ ). At this time, the operation unit 120 receives the current and voltage from the detection unit 110, the excitation current (I ₀ ), the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ) and The iron loss (W ₀ ) can be obtained.

The calculator 120 may calculate the fundamental excitation current I ₀ from the following equation.

Here, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I ₀ is the excitation current, and I _0r is the effective excitation current. Min, I _0x is the ineffective excitation current, θ ₀ is the excitation current power factor angle, _V10 is the excitation circuit supply voltage, X _C is the excitation circuit capacitive reactance, and X _L is the excitation circuit inductive reactance.

In addition, the calculator 120 may calculate the Nth harmonic excitation current I _N0 from the following equation.

where N is the harmonic order, the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I _N0 is the Nth harmonic excitation current, I _N0r is the effective component of the Nth harmonic excitation current, I _N0x is the invalid component of the Nth harmonic excitation current, θ _N0 is the Nth harmonic excitation current power factor angle, V1 _N0 is the Nth harmonic excitation circuit supply voltage, X _C is the excitation circuit’s The capacitive reactance, X _L , represents the inductive reactance of the excitation circuit.

The primary winding outflow current I ₁₂ and the secondary winding outflow current I ₂₁ may be measured from the detection unit 110 .

In addition, the excitation circuit supply voltage (V1 ₀ ) can be calculated by the following equation.

Here, I ₁₁ is the primary winding inrush current, V1 is the primary supply voltage, R1 is the primary winding resistance, and X1 is the primary winding inductive reactance.

The operation unit 120 may obtain the excitation circuit resistance (R ₀ ) by using the iron loss (W ₀ ) as follows.

The calculator 120 may obtain the excitation circuit inductance (L ₀ ) and the excitation circuit capacitance (C ₀ ) as follows by using the fundamental current and the harmonic current.

---- 식(1)

---- Equation (1)

---- 식(2)

---- Equation (2)

Here, N is the harmonic order, V1 _N0 is the corresponding harmonic voltage, and I _N0x is the corresponding harmonic current. In other words, I _0x represents the fundamental wave excitation current invalid component, I _N0x represents the Nth harmonic excitation current invalid component, _V10 represents the fundamental wave excitation circuit supply voltage, and V1 _N0 represents the Nth harmonic excitation circuit supply voltage. X _C is the excitation circuit capacitive reactance, and X _L is the excitation circuit inductive reactance.

The operation unit 120 may obtain the excitation circuit inductance (L ₀ ) from the following equation.

Here, f represents the frequency, and X _L can be obtained as follows from Equation (1) for obtaining the fundamental current.

---- 식(3)

---- Equation (3)

The operation unit 120 may obtain the excitation circuit capacitance (C ₀ ) from the following equation.

Here, X _C can be obtained as follows by substituting Equation (3) for obtaining X _L into Equation (2) for obtaining the harmonic current.

As described above, the operation unit 120 can obtain the excitation current (I ₀ ), the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ) and the iron loss (W ₀ ), The storage determination unit 130 determines that the value of the excitation current (I ₀ ), the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), the excitation circuit capacitance (C ₀ ) or the iron loss (W ₀ ) is out of the reference range. It can be judged that surface deterioration has occurred.

Also, the calculator 120 may obtain a dielectric loss tangent and a dielectric loss from the leakage current Ig of the winding. The storage determination unit 130 may determine that deterioration has occurred when the dielectric loss tangent calculated by the operation unit 120 is greater than a preset reference value. Also, the storage determination unit 130 may determine that deterioration has occurred when the dielectric loss calculated by the operation unit 120 is greater than a preset reference value.

The calculator 120 may obtain the leakage current Ig from the following equation.

Here, I ₁₁ is the primary winding inrush current, I ₁₂ is the primary winding outflow current, I _gr is the leakage current effective component, I _gx is the leakage current invalid component, and θ ₀ is the leakage current power factor angle.

In addition, the insulation resistance (Rg) and the leakage capacitance (Cg) can be obtained from the following equation.

In addition, the calculator 120 may obtain the dielectric loss tangent tanδ from the leakage current Ig by the following equation.

In addition, the operation unit 120 may obtain the dielectric loss (Wg) by the following equation. Here, the dielectric loss value is also called watt loss.

In some examples, when the electric device is a step-up transformer (V1<V2), the excitation circuit resistance (R ₀ ), the excitation circuit inductance (L ₀ ), and the excitation circuit capacitance by substituting the following formula for the excitation current (I ₀ ) The value of (C ₀ ) and the iron loss (W ₀ ) can be obtained.

Here, I ₁₁ is the primary winding inrush current, and I ₂₁ is the secondary winding outflow current.

In addition, by changing Ig to Ig ₂ and _{V10 to V2 0 in} the equation related to leakage current, leakage current, dielectric loss tangent and dielectric loss values can be obtained.

Here, I ₂₂ represents the secondary winding inrush current, and I ₂₁ represents the secondary winding outflow current.

What has been described above is only one embodiment for implementing the apparatus for diagnosing insulation deterioration of electric equipment according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the claims below, Without departing from the gist of the invention, it will be said that the technical spirit of the present invention exists to the extent that various modifications can be made by anyone with ordinary knowledge in the field to which the invention pertains.

110: detection unit
120: arithmetic unit
130: storage decision unit
140: signal output unit

Claims (10)

A detection step of detecting the current and voltage flowing in the winding in an electric device having a primary winding and a secondary winding;
Calculate the values of excitation current (I ₀ ), excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) or iron loss (W ₀ ) with the current and voltage detected in the detection step arithmetic step; and
A storage determination step of storing the values calculated in the calculation step in real time, respectively, and determining that the winding is deteriorated when each calculated value is out of a reference range; includes, wherein the excitation current (I ₀ ) is calculated using the following math It is calculated by the formula,

Here, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, I ₁₂ is the primary winding outflow current, I ₂₁ is the secondary winding outflow current, I _0r is the effective amount of excitation current, and I _0x is the excitation Insulation deterioration diagnosis method of electrical equipment, characterized in that θ ₀ is the excitation current power factor angle, V1 ₀ is the excitation circuit supply voltage, X _C is the excitation circuit capacitive reactance, and X _L is the excitation circuit inductive reactance . The method of claim 1,
The iron loss (W ₀ ) is calculated by the following equation,

The excitation circuit resistance (R ₀ ) is the following equation

Insulation deterioration diagnosis method of electrical equipment, characterized in that calculated by The method of claim 1,
The excitation circuit inductance (L ₀ ) is calculated by the following equation,

The excitation circuit inductive reactance (X _L ) is calculated by the following equation,

A method for diagnosing insulation deterioration of electrical equipment, characterized in that The method of claim 1,
The excitation circuit capacitance (C ₀ ) is calculated by the following equation,

The excitation circuit capacitive capacitance (X _C ) is calculated by the following equation,

Here, I _N0x is the Nth harmonic excitation current invalid.

A method for diagnosing insulation deterioration of electrical equipment, characterized in that The method of claim 1,
In the calculation step, the leakage current is calculated by the following equation,

where I ₁₁ is the primary winding inrush current, I ₁₂ is the primary winding outflow current, I _gr is the leakage current effective component, I _gx is the leakage current invalid component, θ ₀ is the leakage current power factor angle,
Insulation resistance (R _g ) and leakage capacitance (C _g ) are expressed by the following equation

,

Insulation deterioration diagnosis method of electrical equipment, characterized in that calculated by 6. The method of claim 5,
In the calculation step, the dielectric loss tangent (tanδ) is calculated by the following equation,

In the storage determination step, when the dielectric loss tangent (tanδ) is greater than a set reference value, it is determined that the winding is deteriorated. 6. The method of claim 5,
In the calculation step, the dielectric loss (Wg) is calculated by the following equation,

In the storage determination step, when the dielectric loss (Wg) is greater than a set reference value, it is determined that the winding is deteriorated. 6. The method of claim 5,
If the electric device is a step-up transformer or generator, change Ig to Ig ₂ and _{V10 to V2 0 to} obtain leakage current, insulation resistance, dielectric loss tangent, dielectric loss value, and leakage capacitance,

Here, I ₂₂ is the secondary winding inflow current, I ₂₁ is the secondary winding outflow current, the insulation deterioration diagnostic method of an electric device, characterized in that. The method of claim 1,
When the electric device is a step-up transformer, by substituting the following formula for the excitation current (I ₀ ),

Find the values of excitation circuit resistance (R ₀ ), excitation circuit inductance (L ₀ ), excitation circuit capacitance (C ₀ ) and iron loss (W ₀ ), where I ₁₁ is the primary winding inrush current, I ₂₁ is the secondary winding outflow. A method for diagnosing insulation deterioration of an electric device, characterized in that it indicates a current. 10. An apparatus for diagnosing insulation deterioration of electric equipment, characterized in that the insulation deterioration of the electric equipment is diagnosed by the diagnostic method according to any one of claims 1 to 9.

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