Transformer winding response signal online sensing device based on high-frequency mutual inductor

Abstract

A transformer winding response signal online sensing test device based on a high-frequency mutual inductor mainly comprises a transformer body, an iron core, a winding, a high-frequency signal source, a high-frequency mutual inductance device, a signal acquisition device and a computer, the high-frequency mutual inductance device comprises the high-frequency mutual inductor and a signal detection amplification circuit module, and excitation is injected into the winding through the high-frequency signal source; the transformer winding response signal sensing device has the advantages that on the basis of the transformer winding response signal sensing device, effective sensing of the transformer winding response signal can be effectively completed, online monitoring of the transformer winding response is achieved, and a judgment method and tool are provided for early fault signal sensing of the transformer winding.

Description

Technical Field

[0001] The present invention belongs to the field of online sensing of transformer winding response signals, and in particular relates to an online sensing device and a testing method for transformer winding voltage response signals under high-frequency excitation. Background Art

[0002] Under high-frequency excitation, the transformer winding can be equivalent to a lumped equivalent circuit based on resistance, inductance and capacitance. When the winding is deformed, short-circuited or other faults occur, the equivalent lumped circuit parameter values ​​will change accordingly, which is then reflected in the change of the response signal of the transformer winding, that is, the frequency response characteristics of the transformer winding will change accordingly. However, the existing frequency response needs to be tested when the transformer is offline, and abnormalities in the winding state cannot be discovered in a timely and effective manner. In view of this deficiency, it is of great significance to carry out research on online winding response signal perception. Summary of the invention

[0003] In order to overcome the shortcomings of the above background, the present invention provides a method for developing and testing an online sensing device for transformer winding response signals based on a high-frequency mutual inductor, including the following contents:

[0004] The technical solution adopted by the present invention is: an online sensing device for transformer winding response signals based on a high-frequency mutual inductor, characterized in that an iron core (2) is arranged inside a transformer body (1), three layers of windings are wound on the iron core (2), which are divided into a high-voltage winding (3), a medium-voltage winding (4), and a low-voltage winding (5), a high-voltage and high-frequency signal source (6) is connected to the transformer low-voltage winding (5), the lead wire of the high-voltage winding (3) is sleeved in a high-frequency mutual inductor (8) via a coupling capacitor (7), a signal detection and amplification circuit module (9) is connected to the secondary side of the high-frequency mutual inductor (8), a signal acquisition device (10) transmits the acquired electrical signal to a computer (11), and the high-voltage and high-frequency signal source (6) is remotely controlled by the computer (11);

[0005] The high-frequency transformer (8) is an open-type high-frequency current transformer, comprising three components, namely, a nickel-zinc ferrite half magnetic ring (12), an enameled wire wound around the magnetic ring, a transformer housing and a fixing device (13) cast in resin on the outside, and a supporting screw (14) and two nuts (15) to secure the transformer to the high-voltage winding lead wire;

[0006] The signal detection amplifier circuit module (9) connected to the secondary side of the high-frequency mutual inductor (8) is characterized in that it includes: a current-voltage signal conversion circuit, a voltage follower isolation circuit, an industrial frequency filtering circuit, and a signal amplification circuit. The current-voltage signal conversion circuit includes an operational amplifier U1 and a conversion resistor R1 and an anti-parallel diode D. The voltage follower isolation circuit is an operational amplifier U2 and a resistor R2. The in-phase input terminal of the operational amplifier U2 is connected to the current-voltage conversion circuit. The output terminal of the operational amplifier U2 is connected to the high-pass filtering circuit. The industrial frequency filtering circuit includes capacitors C1, C2, resistors R3, R4, R5, an operational amplifier U3, and the inverting input terminal of the operational amplifier U3 is connected to the high-pass filtering circuit. Capacitors C1 and C2 are connected to the voltage follower circuit, one end of R3 is connected to the inverting input terminal of the operational amplifier U3, and the other end is grounded, one end of R4 is connected to the non-inverting input terminal of the operational amplifier U3, and the other end is grounded, and R5 is connected between the non-inverting input terminal and the output terminal of the operational amplifier. The signal amplification circuit includes resistors R6 to R9, capacitors C3 and C4, transistor T1 and a DC power supply DC, the base of the transistor T1 is connected to the capacitor C1 through one end of the resistors R6 and R7, the other end of the capacitor C1 is connected to the output terminal of the power frequency filter circuit, the collector of the transistor T1 is connected to the DC power supply DC through R8, the emitter of the transistor T1 is grounded through the resistor R9, and the collector of the transistor T1 is connected to the DC power supply DC through the coupling capacitor C o Output final voltage signal U0;

[0007] The present invention also aims to provide a testing method for the above device, and its specific measures are:

[0008] A method for online sensing of transformer winding response signals based on high-frequency mutual inductor, using the above-mentioned device to perform online sensing test of transformer winding high-frequency signal response, is characterized in that it includes the following steps:

[0009] The first step is to sleeve a high-frequency mutual inductor (8) onto the lead-out wire of the high-voltage winding (3), connect the secondary side of the high-frequency mutual inductor (8) to a signal detection amplifying circuit module (9), connect the secondary side to the signal detection amplifying circuit module (9) and a signal acquisition device (10), connect the signal acquisition device (10) to a computer (11) via a data cable, and remotely connect a high-voltage and high-frequency signal source (6) to the computer (11);

[0010] Step 2: Use the computer (11) to send a command signal to the high-voltage high-frequency signal source (6), and the high-voltage high-frequency signal source (6) injects a sinusoidal signal with an amplitude of 20V and a frequency of f=100kHz into the transformer low-voltage winding (5), and transmits the sensed high-frequency signal to the computer (11) via the secondary side of the high-frequency mutual inductor (8), the signal detection and amplification circuit module (9) and the signal acquisition device (10);

[0011] Step 3: In the case of step 2, the data obtained is processed and calculated to obtain the current of the lead wire of the high voltage winding (3). The specific calculation method is as follows:

[0012] Given the resistors R6~R9, capacitors C3, C4 of the signal amplifier circuit, and the voltage U0 received by the computer, the output voltage U of the power frequency filter circuit can be obtained according to the following formula: LB :

[0013]

[0014] Find U LB , capacitors C1, C2, resistors R3, R 10 , R4, R5, the filter cut-off frequency f is obtained according to the following formula c The output voltage U of the voltage follower GS :

[0015]

[0016] Find U GS , given the resistor R1 and the number of turns N of the high-frequency transformer, the lead-out current I of the high-voltage winding can be obtained according to the following formula:

[0017]

[0018] Calculate the lead-out current I of the high-voltage winding, given the coupling capacitance C o , the relationship between the port voltage U of the high-voltage winding and the voltage U0 received by the computer is obtained according to the following formula:

[0019]

[0020] Step 4: Repeat steps 2 and 3, set the power frequency f from 100kHz to 1MHz, and change it at intervals of 10kHz to obtain the output amplitude change curve of the high-voltage winding of the transformer, so as to realize the online perception of the transformer winding voltage response signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a flowchart of the present invention.

[0023] Figure 2 This is a structural diagram of the overall device involved in the present invention.

[0024] Figure 3 This is a circuit diagram of a signal detection and amplification circuit module involved in the present invention. DETAILED DESCRIPTION

[0025] The present invention proposes an online sensing device and a testing method for transformer winding voltage response signals under high-frequency excitation, which is characterized in that a high-frequency mutual inductor and a signal detection and amplification circuit module thereof are used to effectively sense the transformer winding voltage response signal, so as to explore the changing law of the response signal when the transformer winding is running online, and specifically comprises the following steps:

[0026] A transformer winding response signal online sensing device based on a high-frequency mutual inductor, characterized in that an iron core (2) is arranged inside a transformer body (1), three layers of windings are wound on the iron core (2), which are divided into a high-voltage winding (3), a medium-voltage winding (4), and a low-voltage winding (5), a high-voltage and high-frequency signal source (6) is connected to the transformer low-voltage winding (5), the lead wire of the high-voltage winding (3) is sleeved in a high-frequency mutual inductor (8) via a coupling capacitor (7), a signal detection and amplification circuit module (9) is connected to the secondary side of the high-frequency mutual inductor (8), a signal acquisition device (10) transmits the acquired electrical signal to a computer (11), and the high-voltage and high-frequency signal source (6) is remotely controlled by the computer (11);

[0027] The high-frequency transformer (8) is an open-type high-frequency current transformer, comprising three components, namely, a nickel-zinc ferrite half magnetic ring (12), an enameled wire wound around the magnetic ring, a transformer housing and a fixing device (13) cast in resin on the outside, and a supporting screw (14) and two nuts (15) to secure the transformer to the high-voltage winding lead wire;

[0028] The signal detection amplifier circuit module (9) connected to the secondary side of the high-frequency mutual inductor (8) is characterized in that it includes: a current-voltage signal conversion circuit, a voltage follower isolation circuit, an industrial frequency filtering circuit, and a signal amplification circuit. The current-voltage signal conversion circuit includes an operational amplifier U1, a conversion resistor R1 and an anti-parallel diode D. The voltage follower isolation circuit is an operational amplifier U2 and a resistor R2. The in-phase input terminal of the operational amplifier U2 is connected to the current-voltage conversion circuit. The output terminal of the operational amplifier U2 is connected to the high-pass filtering circuit. The industrial frequency filtering circuit includes capacitors C1, C2, resistors R3, R4, R5, an operational amplifier U3, and the inverting input terminal of the operational amplifier U3 is connected to the high-pass filtering circuit. Capacitors C1 and C2 are connected to the voltage follower circuit, one end of R3 is connected to the inverting input terminal of the operational amplifier U3, and the other end is grounded, one end of R4 is connected to the non-inverting input terminal of the operational amplifier U3, and the other end is grounded, and R5 is connected between the non-inverting input terminal and the output terminal of the operational amplifier. The signal amplification circuit includes resistors R6 to R9, capacitors C3 and C4, transistor T1 and a DC power supply DC, the base of the transistor T1 is connected to the capacitor C1 through one end of the resistors R6 and R7, the other end of the capacitor C1 is connected to the output terminal of the power frequency filter circuit, the collector of the transistor T1 is connected to the DC power supply DC through R8, the emitter of the transistor T1 is grounded through the resistor R9, and the collector of the transistor T1 is connected to the DC power supply DC through the coupling capacitor C o Output the final voltage signal U0.

[0029] A method for online sensing of transformer winding response signals based on high-frequency mutual inductor, using the above-mentioned device to perform online sensing test of transformer winding high-frequency signal response, is characterized in that it includes the following steps:

[0030] The first step is to sleeve a high-frequency mutual inductor (8) onto the lead-out wire of the high-voltage winding (3), connect the secondary side of the high-frequency mutual inductor (8) to a signal detection amplifying circuit module (9), connect the secondary side to the signal detection amplifying circuit module (9) and a signal acquisition device (10), connect the signal acquisition device (10) to a computer (11) via a data cable, and remotely connect a high-voltage and high-frequency signal source (6) to the computer (11);

[0031] Step 2: Use the computer (11) to send a command signal to the high-voltage high-frequency signal source (6), and the high-voltage high-frequency signal source (6) injects a sinusoidal signal with an amplitude of 20V and a frequency of f=100kHz into the transformer low-voltage winding (5), and transmits the sensed high-frequency signal to the computer (11) via the secondary side of the high-frequency mutual inductor (8), the signal detection and amplification circuit module (9) and the signal acquisition device (10);

[0032] Step 3: In the case of step 2, the data obtained is processed and calculated to obtain the current of the lead wire of the high voltage winding (3). The specific calculation method is as follows:

[0033] Given the resistors R6~R9, capacitors C3, C4 of the signal amplifier circuit, and the voltage U0 received by the computer, the output voltage U of the power frequency filter circuit can be obtained according to the following formula: LB :

[0034]

[0035] Find U LB , capacitors C1, C2, resistors R3, R 10 , R4, R5, the filter cut-off frequency f is obtained according to the following formula c The output voltage U of the voltage follower GS :

[0036]

[0037] Find U GS , given the resistor R1 and the number of turns N of the high-frequency transformer, the lead-out current I of the high-voltage winding can be obtained according to the following formula:

[0038]

[0039] Calculate the lead-out current I of the high-voltage winding, given the coupling capacitance C o , the relationship between the port voltage U of the high-voltage winding and the voltage U0 received by the computer is obtained according to the following formula:

[0040]

[0041] Step 4: Repeat steps 2 and 3, set the power frequency f from 100kHz to 1MHz, and change it at intervals of 10kHz to obtain the output amplitude change curve of the high-voltage winding of the transformer, so as to realize the online perception of the transformer winding voltage response signal.

Claims

1. An online sensing device for transformer winding response signal based on high-frequency mutual inductor, characterized in that: An iron core (2) is arranged inside a transformer body (1), and three layers of windings are wound on the iron core (2), which are divided into a high-voltage winding (3), a medium-voltage winding (4), and a low-voltage winding (5). A high-voltage and high-frequency signal source (6) is connected to the low-voltage winding (5) of the transformer, and a lead wire of the high-voltage winding (3) is sleeved in a high-frequency mutual inductor (8) via a coupling capacitor (7). A signal detection and amplification circuit module (9) is connected to the secondary side of the high-frequency mutual inductor (8). A signal acquisition device (10) transmits the collected electrical signal to a computer (11), and the high-voltage and high-frequency signal source (6) is remotely controlled by the computer (11); The high-frequency transformer (8) is an open-type high-frequency current transformer, comprising three components, namely, a nickel-zinc ferrite half magnetic ring (12), an enameled wire wound around the magnetic ring, a transformer housing and a fixing device (13) cast in resin on the outside, and a supporting screw (14) and two nuts (15) to secure the transformer to the high-voltage winding lead wire; The signal detection amplifier circuit module (9) connected to the secondary side of the high-frequency mutual inductor (8) is characterized in that it includes: a current-voltage signal conversion circuit, a voltage follower isolation circuit, an industrial frequency filtering circuit, and a signal amplification circuit. The current-voltage signal conversion circuit includes an operational amplifier U1 and a conversion resistor R1 and an anti-parallel diode D. The voltage follower isolation circuit is an operational amplifier U2 and a resistor R2. The in-phase input terminal of the operational amplifier U2 is connected to the current-voltage conversion circuit. The output terminal of the operational amplifier U2 is connected to the high-pass filtering circuit. The industrial frequency filtering circuit includes capacitors C1, C2, resistors R3, R4, R5, an operational amplifier U3, and the inverting input terminal of the operational amplifier U3 is connected to the high-pass filtering circuit. Capacitors C1 and C2 are connected to the voltage follower circuit, one end of R3 is connected to the inverting input terminal of the operational amplifier U3, and the other end is grounded, one end of R4 is connected to the non-inverting input terminal of the operational amplifier U3, and the other end is grounded, and R5 is connected between the non-inverting input terminal and the output terminal of the operational amplifier. The signal amplification circuit includes resistors R6 to R9, capacitors C3 and C4, transistor T1 and a DC power supply DC, the base of the transistor T1 is connected to the capacitor C1 through one end of the resistors R6 and R7, the other end of the capacitor C1 is connected to the output terminal of the power frequency filter circuit, the collector of the transistor T1 is connected to the DC power supply DC through R8, the emitter of the transistor T1 is grounded through the resistor R9, and the collector of the transistor T1 is connected to the DC power supply DC through the coupling capacitor C o Output final voltage signal U0; The above-mentioned device is used to perform an online sensing test of a transformer winding high-frequency signal response, which is characterized by comprising the following steps: The first step is to sleeve a high-frequency mutual inductor (8) onto the lead-out wire of the high-voltage winding (3), connect the secondary side of the high-frequency mutual inductor (8) to a signal detection amplifying circuit module (9), connect the secondary side to the signal detection amplifying circuit module (9) and a signal acquisition device (10), connect the signal acquisition device (10) to a computer (11) via a data cable, and remotely connect a high-voltage and high-frequency signal source (6) to the computer (11); Step 2: Use the computer (11) to send a command signal to the high-voltage high-frequency signal source (6), and the high-voltage high-frequency signal source (6) injects a sinusoidal signal with an amplitude of 20V and a frequency of f=100kHz into the transformer low-voltage winding (5), and transmits the sensed high-frequency signal to the computer (11) via the secondary side of the high-frequency mutual inductor (8), the signal detection and amplification circuit module (9) and the signal acquisition device (10); Step 3: In the case of step 2, the data obtained is processed and calculated to obtain the current of the lead wire of the high voltage winding (3). The specific calculation method is as follows: Given the resistors R6~R9, capacitors C3, C4 of the signal amplifier circuit, and the voltage U0 received by the computer, the output voltage U of the power frequency filter circuit can be obtained according to the following formula: LB : Find U LB , capacitors C1, C2, resistors R3, R 10 , R4, R5, the filter cut-off frequency f is obtained according to the following formula c The output voltage U of the voltage follower GS : Find U GS , given the resistor R1 and the number of turns N of the high-frequency transformer, the lead-out current I of the high-voltage winding can be obtained according to the following formula: Calculate the lead-out current I of the high-voltage winding, given the coupling capacitance C o , the relationship between the port voltage U of the high-voltage winding and the voltage U0 received by the computer is obtained according to the following formula: Step 4: Repeat steps 2 and 3, set the power frequency f from 100kHz to 1MHz, and change it at intervals of 10kHz to obtain the output amplitude change curve of the high-voltage winding of the transformer, so as to realize the online perception of the transformer winding voltage response signal.

Images