A method and system for detecting manufacturing defects of dry-type air-core reactor

Abstract

The present invention discloses a method and system for detecting manufacturing defects of dry-type air-core reactors, and belongs to the technical field of manufacturing defect detection of reactors. The present invention solves the problem that the traditional fault detection method in the prior art is difficult to detect manufacturing defects of dry-type air-core reactors; the present invention measures the voltage at both ends of the dry-type air-core reactor and the current flowing through the dry-type air-core reactor, and calculates the total power factor of the dry-type air-core reactor by using the harmonic analysis method; the eddy current loss of the dry-type air-core reactor is calculated according to the structural design parameters of the reactor, and the power factor corresponding to the eddy current loss of the dry-type air-core reactor is obtained; according to different frequency values, a characteristic curve of the relationship between the power factor corresponding to the resistance loss of the dry-type air-core reactor and the frequency is constructed to determine whether the dry-type air-core reactor has manufacturing defects. The present invention effectively realizes the detection of manufacturing defects of dry-type air-core reactors, and can be applied to related fault detection tests of dry-type air-core reactors.

Description

Technical Field

[0001] The invention relates to a method and a system for detecting manufacturing defects of a dry-type air-core reactor, belonging to the technical field of detecting manufacturing defects of reactors. Background Art

[0002] Dry-type air-core reactors have the advantages of simple structure, light weight, small size, good linearity, low loss and easy maintenance. Dry-type air-core reactors can compensate for reactive power, suppress power frequency overvoltage, limit short-circuit overcurrent and filter out high-order harmonics. They are widely used in power systems.

[0003] The dry-type air-core reactor is composed of multiple encapsulations and multiple layers of coils that are coaxially wound in parallel. During the winding process, process defects such as coil turn spacing, height, and radius are inevitable. The above-mentioned process defects will cause a circulating current to form inside the dry-type air-core reactor, causing the local temperature of the encapsulation to rise, which will accelerate insulation aging and reduce the service life of the reactor. It will also aggravate the damage of thermal stress to the encapsulation insulation, causing the reactor encapsulation to crack, which is more likely to cause turn-to-turn short-circuit failures and affect the steady-state operation of the power grid.

[0004] At present, neither the DC resistance method nor the power frequency loss method in the existing technology can effectively reflect the process defects of dry-type air-core reactors. Therefore, it is urgent to propose a method and system for detecting the process defects of dry-type air-core reactors. Summary of the invention

[0005] A brief overview of the present invention is provided below in order to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In view of this, in order to solve the problem that the conventional fault detection method in the prior art is difficult to detect the manufacturing defects of the dry-type air-core reactor, the present invention provides a method and system for detecting the manufacturing defects of the dry-type air-core reactor.

[0007] Technical solution 1 is as follows: A method for detecting manufacturing defects of a dry-type air-core reactor comprises the following steps:

[0008] S1. According to the effective value of the reactor voltage, the effective value of the reactor current and the overall active power loss, the power factor of the dry-type air-core reactor is preliminarily obtained, and the overall active power loss is decomposed into resistance loss and eddy current loss, and then the power factor corresponding to the resistance loss of the dry-type air-core reactor is preliminarily obtained;

[0009] S2. By measuring the voltage across the dry-type air-core reactor and the current flowing through the dry-type air-core reactor, the total power factor of the dry-type air-core reactor is calculated using the harmonic analysis method;

[0010] S3. The eddy current loss of the dry-type air-core reactor is calculated according to the design parameters of the reactor structure, and the power factor corresponding to the eddy current loss of the dry-type air-core reactor is obtained in combination with the power factor of the dry-type air-core reactor;

[0011] S4. According to different frequency values, construct a characteristic curve of the relationship between the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor, take the logarithm of the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor at the same time, and judge whether there is a process manufacturing defect in the dry-type air-core reactor based on the function relationship fitting result obtained after taking the logarithm.

[0012] Furthermore, in S1, the power factor of the dry-type air-core reactor is It is expressed as:

[0013]

[0014] Among them, P is the total active power loss, U is the effective value of the reactor voltage, I is the effective value of the reactor current, and P R is the resistance loss, P e is the eddy current loss;

[0015] Power factor corresponding to resistance loss of dry-type air-core reactor It is expressed as:

[0016]

[0017] Furthermore, the step S2 includes the following steps:

[0018] S21. The voltage U(t) of the detection signal on the dry-type air-core reactor and the current I(t) of the detection signal on the dry-type air-core reactor are obtained by Fourier series expansion;

[0019] S22. According to the voltage of the detection signal on the dry-type air-core reactor and the current of the detection signal on the dry-type air-core reactor, the real and imaginary parts of the fundamental voltage signal and the fundamental current signal within one cycle are obtained, and then the amplitude and initial phase of the fundamental voltage signal and the fundamental current signal are obtained, and finally the power factor of the dry-type air-core reactor is obtained;

[0020] In S21, the voltage U(t) of the detection signal on the dry-type air-core reactor is expressed as:

[0021]

[0022] Where f is the frequency, A uk is the amplitude of the kth voltage harmonic, auk is the real part of the kth voltage harmonic component, b uk is the imaginary part of the kth voltage harmonic component, is the initial phase of the kth voltage harmonic;

[0023] The current I(t) of the detection signal on the dry-type air-core reactor is expressed as:

[0024]

[0025] Among them, A ik is the amplitude of the kth current harmonic, a ik is the real part of the kth harmonic component of the current, b ik is the imaginary part of the kth harmonic component of the current, is the initial phase of the kth current harmonic;

[0026] In S22, within one cycle, the real part a of the fundamental voltage signal u1 It is expressed as:

[0027]

[0028] In one cycle, the imaginary part b of the fundamental voltage signal u1 It is expressed as:

[0029]

[0030] In one cycle, the real part of the fundamental current signal a i1 It is expressed as:

[0031]

[0032] In one cycle, the imaginary part b of the fundamental current signal i1 It is expressed as:

[0033]

[0034] The amplitude of the fundamental current signal U m It is expressed as:

[0035]

[0036] Fundamental current signal amplitude I m It is expressed as:

[0037]

[0038] Fundamental voltage signal initial phase It is expressed as:

[0039]

[0040] Fundamental current signal initial phase They are:

[0041]

[0042] Dry-type air-core reactor power factor It is expressed as:

[0043]

[0044] Furthermore, in S3, the eddy current loss of the dry-type air-core reactor is calculated according to the reactor structure design parameters; the eddy current loss P e It is expressed as:

[0045]

[0046] Where i is the number of layers, k is the number of turns, ω is the angular frequency, and D i is the coil diameter, d i is the wire diameter, ρ is the wire resistivity, B rik is the radial magnetic flux density, B zik is the axial magnetic flux density, n i is the number of turns per unit height, h i is the height;

[0047] Radial magnetic flux density B rik It is expressed as:

[0048]

[0049] Among them, r i is the radius of the i-th coil, r j is the radius of the j-th coil, n j is the number of turns per unit height of the jth layer, x l is the kth turn of the coil in the lth layer, x k is the kth turn of the coil in the i-th layer, h j is the height of the j-th coil, I j is the current flowing through the j-th coil, μ 0 is the magnetic permeability in vacuum, cosθ is the cosine of the radial angle between any point of the k-turn coil in the i-th layer and any point of the l-turn coil in the j-th layer;

[0050] Axial magnetic flux density B zik It is expressed as:

[0051]

[0052] Integrating the above formula, the power factor corresponding to the resistance loss of the dry-type air-core reactor is It is expressed as:

[0053]

[0054] Furthermore, in S4, at any frequency f, voltages of different frequencies are applied to the dry-type air-core reactor, current values ​​at different frequencies are measured, and power factors of the dry-type air-core reactor at different frequencies are calculated. According to the structural design parameters of the dry-type air-core reactor, the eddy current loss P of the dry-type air-core reactor at different frequencies is calculated. e , and then calculate the power factor corresponding to the resistance loss of the dry-type air-core reactor at different frequencies And get the power factor corresponding to the resistance loss of the dry air-core reactor Characteristic curve of relationship with frequency f;

[0055] When there is no manufacturing defect in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates The characteristic curve of the relationship with frequency f changes linearly. When there are manufacturing defects in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates is The characteristic curve with respect to frequency f changes in a nonlinear relationship;

[0056] Power factor corresponding to resistance loss of dry-type air-core reactor Take the logarithm of the frequency f at the same time, and further obtain the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor The characteristic curve of the relationship between the logarithm of the frequency and the lgf is calculated by the least square method to calculate the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor. The data is fitted with the logarithm of the frequency lgf, and its functional relationship satisfies the polynomial function, and the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor is obtained. The fitting result of the functional relationship with the logarithm of frequency lgf;

[0057] Logarithm of power factor corresponding to resistance loss of dry-type air-core reactor The fitting result of the functional relationship with the logarithm of the frequency lgf is expressed as:

[0058]

[0059] Among them, a 2 is the coefficient of the quadratic term of the logarithm lgf, a 1 is the coefficient of the first-order term of the logarithm lgf, a 0 is the constant term coefficient;

[0060] The coefficient a of the quadratic term of the logarithm lgf 2 The absolute value of the logarithm lgf and the coefficient a of the first term 1 The ratio of the absolute values ​​of is defined as the nonlinear coefficient β;

[0061] The nonlinear coefficient β is expressed as:

[0062]

[0063] The more serious the manufacturing defects of dry-type air-core reactors, the logarithm of the power factor corresponding to the resistance loss of dry-type air-core reactors The greater the degree of nonlinearity shown in the fitting result of the logarithmic lgf function relationship with the frequency, the larger the nonlinear coefficient β. When β>0.16, the temperature rise of the dry-type air-core reactor exceeds the standard requirements, and it is determined that the dry-type air-core reactor has a manufacturing defect.

[0064] Technical Solution 2: A dry-type air-core reactor manufacturing defect detection system, used to implement a dry-type air-core reactor manufacturing defect detection method described in Technical Solution 1, the system includes a variable frequency power supply, a first resistor divider, a second resistor divider, a current signal sampling resistor, a power factor measurement device and a host computer;

[0065] The variable frequency power supply is connected to the first resistor divider, the second resistor divider, the current signal sampling resistor and the power factor measurement device respectively, and the variable frequency power supply is grounded;

[0066] The power factor measuring device is connected to the first resistor voltage divider, the second resistor voltage divider and the current signal sampling resistor respectively;

[0067] The first resistor voltage divider, the second resistor voltage divider and the current signal sampling resistor are connected in sequence;

[0068] The host computer is connected to the power factor measuring device.

[0069] Further, the power factor measuring device includes an A / D converter, an embedded computer and a photoelectric converter;

[0070] The A / D converter, embedded computer, photoelectric converter and host computer are connected in sequence;

[0071] The host computer includes a data receiving module, a data calculation module, a data display module and a data storage module;

[0072] The data receiving module, the data calculating module, the data display module and the data storage module are connected in sequence.

[0073] The beneficial effects of the present invention are as follows: the present invention measures the total power factor of the dry-type air-core reactor and calculates the eddy current loss at different frequencies, further calculates the power factor corresponding to the resistance loss, establishes the characteristic relationship between the power factor corresponding to the resistance loss of the dry-type air-core reactor and the frequency, and uses the data fitting method to solve the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor. A characteristic curve of the relationship between the frequency and the logarithm lgf is drawn, and a nonlinear coefficient is defined. A detection method for detecting process defects of dry-type air-core reactors using the nonlinear coefficient is proposed to solve the technical problem that process defects of dry-type air-core reactors cannot be detected in the prior art, thereby ensuring the production quality of dry-type air-core reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0075] Figure 1 A schematic diagram of a process flow of a dry-type air-core reactor manufacturing defect detection method;

[0076] Figure 2 This is a simplified model diagram of a coaxial thin-walled solenoid;

[0077] Figure 3 The power factor corresponding to the resistance loss of the dry-type air-core reactor Schematic diagram of the characteristic curve of the relationship with frequency f;

[0078] Figure 4 The logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor Schematic diagram of the characteristic curve of the relationship with the logarithm of the frequency lgf;

[0079] Figure 5 A schematic diagram of a manufacturing defect detection system for a dry-type air-core reactor;

[0080] Figure 6 It is a schematic diagram of the application flow of the power factor measurement device;

[0081] Figure 7 It is the structural diagram of the upper computer;

[0082] Figure 8 Schematic diagram of eddy current loss calculation process.

[0083] Description of the drawings: 1. Dry-type air-core reactor; 11. Resistor; 12. Inductor; 2. Variable frequency power supply; 3. First resistor voltage divider; 4. Second resistor voltage divider; 5. Current signal sampling resistor; 6. Power factor measuring device; 7. Host computer. DETAILED DESCRIPTION

[0084] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0085] Example 1: Reference Figure 1-Figure 8 The present embodiment is described in detail. A method for detecting manufacturing defects of a dry-type air-core reactor comprises the following steps:

[0086] S1. According to the effective value of the reactor voltage, the effective value of the reactor current and the overall active power loss, the power factor of the dry-type air-core reactor is preliminarily obtained, and the overall active power loss is decomposed into resistance loss and eddy current loss, and then the power factor corresponding to the resistance loss of the dry-type air-core reactor is preliminarily obtained;

[0087] S2. By measuring the voltage across the dry-type air-core reactor and the current flowing through the dry-type air-core reactor, the total power factor of the dry-type air-core reactor is calculated using the harmonic analysis method;

[0088] S3. The eddy current loss of the dry-type air-core reactor is calculated according to the design parameters of the reactor structure, and the power factor corresponding to the eddy current loss of the dry-type air-core reactor is obtained in combination with the power factor of the dry-type air-core reactor;

[0089] S4. According to different frequency values, construct a characteristic curve of the relationship between the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor, take the logarithm of the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor at the same time, and judge whether there is a process manufacturing defect in the dry-type air-core reactor based on the function relationship fitting result obtained after taking the logarithm.

[0090] Furthermore, in S1, the power factor of the dry-type air-core reactor is It is expressed as:

[0091]

[0092] Among them, P is the total active power loss, U is the effective value of the reactor voltage, I is the effective value of the reactor current, and P R is the resistance loss, P e is the eddy current loss;

[0093] Power factor corresponding to resistance loss of dry-type air-core reactor It is expressed as:

[0094]

[0095] Specifically, for dry-type air-core reactors, the overall active power loss P consists of two parts, one of which is the resistance loss PR The other part is provided by eddy current loss P e supply.

[0096] Furthermore, the step S2 includes the following steps:

[0097] S21. The voltage U(t) of the detection signal on the dry-type air-core reactor and the current I(t) of the detection signal on the dry-type air-core reactor are obtained by Fourier series expansion;

[0098] S22. According to the voltage of the detection signal on the dry-type air-core reactor and the current of the detection signal on the dry-type air-core reactor, the real and imaginary parts of the fundamental voltage signal and the fundamental current signal within one cycle are obtained, and then the amplitude and initial phase of the fundamental voltage signal and the fundamental current signal are obtained, and finally the power factor of the dry-type air-core reactor is obtained;

[0099] In S21, the voltage U(t) of the detection signal on the dry-type air-core reactor is expressed as:

[0100]

[0101] Where f is the frequency, A uk is the amplitude of the kth voltage harmonic, a uk is the real part of the kth voltage harmonic component, b uk is the imaginary part of the kth voltage harmonic component, is the initial phase of the kth voltage harmonic;

[0102] The current I(t) of the detection signal on the dry-type air-core reactor is expressed as:

[0103]

[0104] Among them, A ik is the amplitude of the kth current harmonic, a ik is the real part of the kth harmonic component of the current, b ik is the imaginary part of the kth harmonic component of the current, is the initial phase of the kth current harmonic;

[0105] In S22, within one cycle, the real part a of the fundamental voltage signal u1 It is expressed as:

[0106]

[0107] In one cycle, the imaginary part b of the fundamental voltage signal u1 It is expressed as:

[0108]

[0109] In one cycle, the real part of the fundamental current signal a i1 It is expressed as:

[0110]

[0111] In one cycle, the imaginary part b of the fundamental current signal i1 It is expressed as:

[0112]

[0113] The amplitude of the fundamental current signal U m It is expressed as:

[0114]

[0115] Fundamental current signal amplitude I m It is expressed as:

[0116]

[0117] Fundamental voltage signal initial phase It is expressed as:

[0118]

[0119] Fundamental current signal initial phase They are:

[0120]

[0121] Dry-type air-core reactor power factor It is expressed as:

[0122]

[0123] Further, in said S3, the eddy current loss of the dry-type air-core reactor is calculated according to the design parameters of the reactor structure;

[0124] Eddy current loss P e It is expressed as:

[0125]

[0126] Where i is the number of layers, k is the number of turns, ω is the angular frequency, and D i is the coil diameter, d i is the wire diameter, ρ is the wire resistivity, B rik is the radial magnetic flux density, B zik is the axial magnetic flux density, n i is the number of turns per unit height, h i is the height;

[0127] Radial magnetic flux density Brik It is expressed as:

[0128]

[0129] Among them, r i is the radius of the i-th coil, r j is the radius of the j-th coil, n j is the number of turns per unit height of the jth layer, x l is the kth turn of the coil in the lth layer, x k is the kth turn of the coil in the i-th layer, h j is the height of the j-th coil, I j is the current flowing through the j-th coil, μ 0 is the magnetic permeability in vacuum, cosθ is the cosine of the radial angle between any point of the k-turn coil in the i-th layer and any point of the l-turn coil in the j-th layer;

[0130] Axial magnetic flux density B zik It is expressed as:

[0131]

[0132] Integrating the above formula, the power factor corresponding to the resistance loss of the dry-type air-core reactor is It is expressed as:

[0133]

[0134] Specifically, refer to Figure 2 , the dry-type air-core reactor is made of multiple coaxially wound aluminum wires connected in parallel, and each coil can be regarded as a thin-walled solenoid;

[0135] refer to Figure 8 , input the size parameters of each branch, namely frequency f, number of coil layers m, number of turns per unit height n, diameter D, height h, current I and winding wire diameter d, read the parameters of each branch, calculate the magnetic field of the kth turn of the lth turn on the jth winding of the reactor at the kth turn on the i-th winding, the initial values ​​of i, k, j and l are all 1, and judge whether l is less than or equal to n j h j If yes, then l = l + 1, if no, determine whether j is less than or equal to m, if yes, then l = 1, j = j + 1, if no, perform radial magnetic flux density B rik , axial magnetic flux density B zik and loss P eik Calculate whether k is less than or equal to n i h iIf yes, l=1, j=1, k=k+1, if no, determine whether i is less than or equal to m, if yes, l=1, j=1, k=k, i=i+1, if no, calculate the final eddy current loss P e .

[0136] Furthermore, in S4, at any frequency f, voltages of different frequencies are applied to the dry-type air-core reactor, current values ​​at different frequencies are measured, and power factors of the dry-type air-core reactor at different frequencies are calculated. According to the structural design parameters of the dry-type air-core reactor, the eddy current loss P of the dry-type air-core reactor at different frequencies is calculated. e , and then calculate the power factor corresponding to the resistance loss of the dry-type air-core reactor at different frequencies And get the power factor corresponding to the resistance loss of the dry air-core reactor Characteristic curve of relationship with frequency f;

[0137] When there is no manufacturing defect in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates The characteristic curve of the relationship with frequency f changes linearly. When there are manufacturing defects in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates is The characteristic curve with respect to frequency f changes in a nonlinear relationship;

[0138] Power factor corresponding to resistance loss of dry-type air-core reactor Take the logarithm of the frequency f at the same time, and further obtain the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor The characteristic curve of the relationship between the logarithm of the frequency and the lgf is calculated by the least square method to calculate the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor. The data is fitted with the logarithm of the frequency lgf, and its functional relationship satisfies the polynomial function, and the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor is obtained. The fitting result of the functional relationship with the logarithm of frequency lgf;

[0139] Logarithm of power factor corresponding to resistance loss of dry-type air-core reactor The fitting result of the functional relationship with the logarithm of the frequency lgf is expressed as:

[0140]

[0141] Among them, a 2 is the coefficient of the quadratic term of the logarithm lgf, a 1 is the coefficient of the first-order term of the logarithm lgf, a 0 is the constant term coefficient;

[0142] The coefficient a of the quadratic term of the logarithm lgf 2 The absolute value of the logarithm lgf and the coefficient a of the first term 1 The ratio of the absolute values ​​of is defined as the nonlinear coefficient β;

[0143] The nonlinear coefficient β is expressed as:

[0144]

[0145] The more serious the manufacturing defects of dry-type air-core reactors, the logarithm of the power factor corresponding to the resistance loss of dry-type air-core reactors The greater the nonlinearity of the fitting result of the logarithmic lgf function relationship with the frequency, the greater the nonlinear coefficient β. When β>0.16, the temperature rise of the dry-type air-core reactor exceeds the standard requirements, and it is determined that the dry-type air-core reactor has a process manufacturing defect, that is, the manufactured dry-type air-core reactor is an unqualified product.

[0146] Specifically, refer to Figure 3 The value of any frequency f includes but is not limited to 1Hz, 10Hz, 50Hz, 100Hz, 500Hz, 1kHz, 5kHz, 10kHz and 50kHz, Hz is the frequency unit, % is the power factor corresponding to the resistance loss of the dry-type air-core reactor Units;

[0147] refer to Figure 4 , the logarithm of the power factor corresponding to the resistance loss of the defective dry-type air-core reactor The fitting result of the functional relationship with the logarithm of the frequency lgf is expressed as:

[0148]

[0149] Logarithm of power factor corresponding to resistance loss of defective dry-type air-core reactor Functional relationship with the logarithm of frequency lgf, goodness of fit R 2 The value is 0.98;

[0150] Logarithm of power factor corresponding to resistance loss of dry-type air-core reactor without defects The fitting result of the functional relationship with the logarithm of the frequency lgf is expressed as:

[0151]

[0152] Logarithm of power factor corresponding to resistance loss of dry-type air-core reactor without defects Functional relationship with the logarithm of frequency lgf, goodness of fit R 2 The value is 1.

[0153] Example 2: Reference Figure 5-Figure 7 The present embodiment is described in detail, a dry-type air-core reactor manufacturing defect detection system is used for a dry-type air-core reactor manufacturing defect detection method described in embodiment 1, the system comprises a variable frequency power supply 2, a first resistor divider 3, a second resistor divider 4, a current signal sampling resistor 5, a power factor measurement device 6 and a host computer 7;

[0154] The variable frequency power supply 2 is connected to the first resistor divider 3, the second resistor divider 4, the current signal sampling resistor 5 and the power factor measurement device 6 respectively, and the variable frequency power supply 2 is grounded;

[0155] The power factor measuring device 6 is connected to the first resistor voltage divider 3, the second resistor voltage divider 4 and the current signal sampling resistor 5 respectively;

[0156] The first resistor voltage divider 3, the second resistor voltage divider 4 and the current signal sampling resistor 5 are connected in sequence;

[0157] The host computer 7 is connected to the power factor measuring device 6 .

[0158] Further, the power factor measuring device 6 includes an A / D converter, an embedded computer and a photoelectric converter;

[0159] The A / D converter, embedded computer, photoelectric converter and host computer 7 are connected in sequence;

[0160] The host computer 7 includes a data receiving module, a data calculation module, a data display module and a data storage module;

[0161] The data receiving module, the data calculating module, the data display module and the data storage module are connected in sequence;

[0162] Specifically, refer to Figure 5 The dry-type air-core reactor 1 includes a resistor 11 and an inductor 12. When performing manufacturing defect detection of the dry-type air-core reactor, the dry-type air-core reactor 1 is connected in parallel with the first resistor divider 3 and the second resistor divider 4;

[0163] refer to Figure 6 The power factor measuring device 6 has a built-in filter amplifier conditioning circuit, and the voltage U on the first resistor divider 3 and the second resistor divider 4 L And the voltage U on the current signal sampling resistor 5 IAfter being filtered and amplified by the filter-amplifier conditioning circuit, the analog quantity is converted into a digital quantity through the A / D converter, and then the amplitude and initial phase of the fundamental voltage signal and fundamental current signal of the dry-type air-core reactor are calculated by the embedded computer using the harmonic analysis method, and then optical coupling isolation is performed, and the optical-to-electric converter is used to upload the signal to the host computer in the form of optical fiber communication for further calculation, display, storage and other processing;

[0164] refer to Figure 7 The data calculation module is used to calculate the total power factor of the dry-type air-core reactor, the eddy current loss of the dry-type air-core reactor, and the power factor corresponding to the resistance loss of the dry-type air-core reactor. calculate.

[0165] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

Claims

1. A method for detecting manufacturing defects of dry-type air-core reactors, characterized in that: The following steps are involved: S1. According to the effective value of the reactor voltage, the effective value of the reactor current and the overall active power loss, the total power factor of the dry-type air-core reactor is preliminarily obtained, and the overall active power loss is decomposed into resistance loss and eddy current loss, and then the power factor corresponding to the resistance loss of the dry-type air-core reactor is preliminarily obtained; S2. By measuring the voltage across the dry-type air-core reactor and the current flowing through the dry-type air-core reactor, the total power factor of the dry-type air-core reactor is calculated using the harmonic analysis method; S3. The eddy current loss of the dry-type air-core reactor is calculated according to the design parameters of the reactor structure, and the power factor corresponding to the eddy current loss of the dry-type air-core reactor is obtained by combining the total power factor of the dry-type air-core reactor; S4. According to different frequency values, construct a characteristic curve of the relationship between the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor, take the logarithm of the power factor and frequency corresponding to the resistance loss of the dry-type air-core reactor at the same time, and judge whether there is a process manufacturing defect in the dry-type air-core reactor based on the function relationship fitting result obtained after taking the logarithm.

2. A method for detecting manufacturing defects of a dry-type air-core reactor according to claim 1, characterized in that: The total power factor of the dry-type air-core reactor in S1 is It is expressed as: ； in, is the total active power loss, is the effective value of the reactor voltage, is the effective value of the reactor current, is the resistance loss, is the eddy current loss; Power factor corresponding to resistance loss of dry-type air-core reactor It is expressed as: 。 3. A method for detecting manufacturing defects of a dry-type air-core reactor according to claim 2, characterized in that: The S2 comprises the following steps: S21. The voltage of the detection signal on the dry-type air-core reactor is obtained by Fourier series expansion and the current of the detection signal on the dry air-core reactor ; S22. According to the voltage of the detection signal on the dry-type air-core reactor and the current of the detection signal on the dry-type air-core reactor, the real and imaginary parts of the fundamental voltage signal and the fundamental current signal within one cycle are obtained, and then the amplitude and initial phase of the fundamental voltage signal and the fundamental current signal are obtained, and finally the total power factor of the dry-type air-core reactor is obtained; In S21, the voltage of the detection signal on the dry-type air-core reactor is It is expressed as: ； in, is the frequency, for The amplitude of the sub-voltage harmonics, for The real part of the sub-voltage harmonic component, for The imaginary part of the sub-voltage harmonic component, for The initial phase of the sub-voltage harmonics; Current detection signal on dry-type air-core reactor It is expressed as: ； in, for The amplitude of the sub-current harmonics, for The real part of the sub-harmonic components of the current, for The imaginary part of the sub-harmonic component of the current, for The initial phase of the sub-current harmonics; In S22, within one cycle, the real part of the fundamental voltage signal It is expressed as: ； In one cycle, the imaginary part of the fundamental voltage signal It is expressed as: ； In one cycle, the real part of the fundamental current signal It is expressed as: ； In one cycle, the imaginary part of the fundamental current signal It is expressed as: ； Amplitude of fundamental current signal It is expressed as: ； Fundamental current signal amplitude It is expressed as: ； Fundamental voltage signal initial phase It is expressed as: ； Fundamental current signal initial phase They are: ； Total power factor of dry-type air-core reactor It is expressed as: 。 4. A method for detecting manufacturing defects of a dry-type air-core reactor according to claim 3, characterized in that: The S4, at any frequency Under the condition of different frequencies, voltages of different frequencies are applied to the dry-type air-core reactor, the current values ​​at different frequencies are measured, and the total power factor of the dry-type air-core reactor at different frequencies is calculated. According to the structural design parameters of the dry-type air-core reactor, the eddy current loss of the dry-type air-core reactor at different frequencies is calculated. , and then calculate the power factor corresponding to the resistance loss of the dry-type air-core reactor at different frequencies , and obtain the power factor corresponding to the resistance loss of the dry-type air-core reactor With frequency The relationship characteristic curve of When there is no manufacturing defect in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates With frequency The characteristic curve of the relationship changes in a linear relationship. When there are manufacturing defects in the dry-type air-core reactor, the power factor corresponding to the resistance loss of the dry-type air-core reactor in the double logarithmic coordinates With frequency The characteristic curve of the relationship shows a nonlinear change; Power factor corresponding to resistance loss of dry-type air-core reactor With frequency At the same time, take the logarithm to further obtain the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor Logarithm of frequency The relationship characteristic curve of the dry-type air-core reactor resistance loss corresponding to the logarithm of the power factor is calculated using the least squares method. Logarithm of frequency The data is fitted, and its functional relationship satisfies the polynomial function, and the logarithm of the power factor corresponding to the resistance loss of the dry-type air-core reactor is obtained. Logarithm of frequency The functional relationship fitting results of ; Logarithm of power factor corresponding to resistance loss of dry-type air-core reactor Logarithm of frequency The functional relationship fitting result is expressed as: ； in, Logarithm The quadratic coefficient of Logarithm The linear coefficient of is the constant term coefficient; The logarithm The quadratic coefficient of The absolute value and logarithm of The linear coefficient of The ratio of the absolute values ​​of is defined as the nonlinear coefficient ; Nonlinear coefficient It is expressed as: ； The more serious the manufacturing defects of dry-type air-core reactors, the logarithm of the power factor corresponding to the resistance loss of dry-type air-core reactors Logarithm of frequency The greater the nonlinearity of the function relationship fitting result, the larger the nonlinear coefficient The bigger, the When the temperature rise of the dry-type air-core reactor exceeds the standard requirements, it is determined that the dry-type air-core reactor has process manufacturing defects.

5. A dry-type air-core reactor manufacturing defect detection system, characterized in that: A method for detecting manufacturing defects of a dry-type air-core reactor according to any one of claims 1 to 4, the system comprising a variable frequency power supply (2), a first resistor divider (3), a second resistor divider (4), a current signal sampling resistor (5), a power factor measuring device (6) and a host computer (7); One end of the variable frequency power supply (2) is connected to the first resistor divider (3), and the other end is connected to the current signal sampling resistor (5); one end of the second resistor divider (4) is connected to the first resistor divider (3), and the other end is connected to the current signal sampling resistor (5); and the variable frequency power supply (2) is grounded; The power factor measuring device (6) is connected to the first resistor voltage divider (3), the second resistor voltage divider (4) and the current signal sampling resistor (5) respectively; The first resistor voltage divider (3), the second resistor voltage divider (4) and the current signal sampling resistor (5) are connected in sequence; The host computer (7) is connected to the power factor measuring device (6).

6. A dry-type air-core reactor manufacturing defect detection system according to claim 5, characterized in that: The power factor measuring device (6) comprises an A / D converter, an embedded computer and a photoelectric converter; The A / D converter, embedded computer, photoelectric converter and host computer (7) are connected in sequence; The host computer (7) comprises a data receiving module, a data calculation module, a data storage module and a data storage module; The data receiving module, the data calculating module, the data display module and the data storage module are connected in sequence.

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