CN207798995U - A kind of oscillation wave detection deformation of transformer winding circuit - Google Patents

Abstract

The application discloses an oscillation wave detection circuit for transformer winding deformation. The circuit includes a DC high-voltage power supply. The DC high-voltage power supply is electrically connected to the three-phase neutral point of the primary winding of the transformer. A short-circuit switch is provided between the DC high-voltage power supply and the primary winding. One end of the short-circuit switch is electrically connected between the DC high-voltage power supply and the primary winding, and the other end is grounded; the end screen of the bushing capacitor of each phase of the primary winding is electrically connected to a voltage-dividing capacitor, and both ends of the voltage-dividing capacitor are connected to the waveform measurement and analysis device, the voltage divider capacitors are grounded. This application uses the short circuit switch to close the ground to form the ground stray capacitance, the bushing capacitance and the leakage reactance or excitation impedance oscillation circuit of the primary winding to the secondary winding, and uses the waveform measurement and analysis device to measure the three-phase voltage response curve of the primary winding. Analyze and compare the three-phase voltage response curves to determine whether the transformer winding is deformed. This application is suitable for detecting latent faults of transformer winding deformation.

Description

An Oscillatory Wave Detecting Transformer Winding Deformation Circuit

technical field

The present application relates to the technical field of transformer winding state evaluation and detection, in particular to an oscillation wave detection transformer winding deformation circuit.

Background technique

The axial or radial dimensional changes of power transformer windings under the action of mechanical force or electrodynamic force are usually characterized by local twisting, bulging or displacement of windings. When the transformer is subjected to short-circuit current impact or impact during transportation, winding deformation may occur, which will directly affect the safe operation of the transformer. According to statistics, the latent fault of 110kV and above power transformer winding with slight deformation is one of the main causes of power transformer damage and grid failure. The existing main detection methods for winding deformation include frequency response method and impedance method. The frequency response method has low measurement voltage, unintuitive measurement results, and cannot be quantitatively judged. The horizontal and vertical comparison of the frequency response curve can make a comprehensive judgment; the short-circuit impedance method is the earliest detection method for transformer winding deformation, but it is not easy to find out the slight deformation of the winding.

Utility model content

In order to solve the problems in the prior art, this application proposes an oscillatory wave detection transformer winding deformation loop, the loop structure is simple, the detection signal is strong, the accuracy of the transformer winding deformation is high, and it is suitable for the latent fault detection of the transformer winding deformation.

In order to achieve the above purpose, the technical solution adopted in this application is: including a DC high-voltage power supply, the DC high-voltage power supply is electrically connected to the three-phase neutral point of the primary winding of the transformer, and a short-circuit switch is provided between the DC high-voltage power supply and the primary winding. One end of the switch is electrically connected between the DC high-voltage power supply and the primary winding, and the other end is grounded; each phase of the primary winding is provided with a bushing capacitor and a number of stray capacitors to the ground, and the end screen of the bushing capacitor of each phase is A voltage-dividing capacitor is connected, and both ends of the voltage-dividing capacitor are connected to the waveform measurement and analysis device, and the voltage-dividing capacitors are all grounded; after the primary winding is charged with a DC voltage, the short-circuit switch is closed to form stray capacitance to the ground, a sleeve Tube capacitance and primary winding to secondary winding leakage reactance or excitation impedance oscillating circuit, measure the three-phase voltage response curve of the primary winding through the waveform measurement and analysis device, and judge whether the transformer winding is deformed according to the three-phase voltage response curve.

The primary winding of the transformer is a star winding.

The first ends of the three phases of the primary winding of the transformer are suspended in the air.

The first ends of the three phases of the primary winding of the transformer are all electrically connected to compensation capacitors, and one end of the compensation capacitors is grounded.

The secondary winding of the transformer is short-circuited by a short-circuit wire.

The DC high-voltage power supply includes a DC high-voltage generator connected to the power supply, the DC high-voltage generator is electrically connected to the three-phase neutral point of the primary winding of the transformer, the DC high-voltage generator is grounded, and one end of the short-circuit switch is electrically connected to the DC high-voltage generator and primary winding.

The DC high voltage generator is connected to a 220V AC power supply.

A protective resistor is set between the DC high voltage generator and the short circuit switch.

Compared with the prior art, this application utilizes a DC high-voltage power supply to apply DC high-voltage power to the three-phase neutral point of the primary winding of the transformer, and sets a short-circuit switch between the DC high-voltage power supply and the primary winding, and one end of the short-circuit switch is electrically connected to Between the DC high-voltage power supply and the primary winding, the other end of the short-circuit switch is grounded, and the short-circuit switch is used to close the ground, forming stray capacitance to the ground, bushing capacitance, and leakage reactance or excitation impedance oscillation loop between the primary winding and the secondary winding. The end screen of the bushing capacitor of the phase is electrically connected with a voltage dividing capacitor, both ends of the voltage dividing capacitor are connected to the waveform measurement and analysis device, and the waveform measurement and analysis device is used to measure the three-phase voltage response curve of the primary winding, and analyze and compare the three-phase voltage response The frequency of the curve, the oscillation time, the consistency of the three-phase waveform, the variance and the mean difference can judge whether the transformer winding is deformed. The test circuit of this application is simple, the detection signal is strong, and it has the characteristics of high voltage and high accuracy. It is suitable for transformer winding deformation latency. fault detection.

Description of drawings

In order to illustrate the technical solution of the present application more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, on the premise of not paying creative labor, Additional drawings can also be derived from these drawings.

Fig. 1 is the circuit electrical schematic diagram of the present application;

Among them, 1-DC high voltage generator, 2-short-connected wire, 3-secondary winding, 4-waveform measurement and analysis device, 5-compensation capacitor, 6-voltage dividing capacitor, 7-transformer, R is protection resistor, K ₁ is the short circuit switch, C ₀ is the bushing capacitance, C ₁ is the ground stray capacitance, and L _m is the primary winding.

Detailed ways

The present application will be further explained below in combination with specific embodiments and accompanying drawings.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description serve to explain the principles of the application.

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, In other words, other drawings can also be obtained from these drawings without paying creative labor.

Referring to Fig. 1, the present application includes a DC high-voltage power supply, which is electrically connected to the three-phase neutral point of the primary winding L _m of the transformer 7, and a short-circuit switch K ₁ is provided between the DC high-voltage power supply and the primary winding L _m to short-circuit One end of the switch K ₁ is electrically connected between the DC high-voltage power supply and the primary winding L _m , and the other end is grounded; each phase of the primary winding L _m is provided with a bushing capacitance C ₀ and several stray capacitances C ₁ to the ground. The end screen of the bushing capacitor _C0 is electrically connected to a voltage dividing capacitor 6, both ends of the voltage dividing capacitor 6 are connected to the waveform measurement and analysis device 4, and the voltage dividing capacitor 6 is grounded; after the primary winding L _m is charged with DC voltage, the short circuit is closed Connect the switch K ₁ to form the ground stray capacitance C ₁ , bushing capacitance C ₀ and the leakage reactance or excitation impedance oscillation loop of the primary winding L _m to the secondary winding 3, and measure the primary winding L _m through the waveform measurement and analysis device 4 Three-phase voltage response curve, according to the three-phase voltage response curve to determine whether the transformer winding is deformed.

The primary winding L _m of the transformer 7 is a star winding, and the three-phase first ends of the primary winding L _m of the transformer 7 are suspended; or the stray capacitance C ₁ to the ground, the bushing capacitance C ₀ and the primary winding L _m to the secondary winding When the leakage reactance of 3 or the duration of the oscillating wave of the excitation impedance oscillating circuit is less than 3 cycles, the first ends of the three phases of the primary winding L _m of the transformer 7 are all electrically connected to the compensation capacitor 5, and one end of the compensation capacitor 5 is grounded.

If the stray capacitance C ₁ to ground, the bushing capacitance C ₀ and the leakage reactance oscillation loop of the primary winding L _m to the secondary winding 3 are formed, the secondary winding 3 of the transformer 7 is short-circuited through the short-circuit wire 2 .

Further optimally, the DC high voltage power supply includes a DC high voltage generator 1 connected to the power supply, the DC high voltage generator 1 is electrically connected to the three-phase neutral point of the primary winding L _m of the transformer 7, the DC high voltage generator 1 is grounded, and the switch is shorted One end of K ₁ is electrically connected between the DC high voltage generator 1 and the primary winding L _m . The DC high voltage generator 1 is connected to a 220V AC power supply. A protective resistor R is set between the DC high voltage generator 1 and the short circuit switch _K1 .

In addition, the transformer winding deformation is detected by using the oscillating loop formed between the transformer leakage reactance or excitation impedance and the capacitive bushing capacitance, the stray capacitance of the winding to the ground and the external compensation capacitance. The DC voltage is applied to the head end of the primary winding, and through two short-circuit switches, the DC high-voltage circuit is disconnected first, and then the neutral line of the primary winding is connected to the ground, which can also detect the deformation of the transformer winding.

In this application, the primary star-shaped winding of the transformer is suspended in the air or connected to the grounded compensation capacitor, the secondary winding is short-circuited, and a DC voltage is applied to the neutral point connecting line of the transformer star-shaped winding, and it is quickly grounded, and the voltage response waveform of the circuit is measured. It is composed of DC high voltage generator 1, protection resistor R, short circuit switch K ₁ , waveform measurement and analysis device 4, compensation capacitor 5, voltage dividing capacitor 6, etc. By measuring the three-phase voltage waveform of the primary winding, and comparing and analyzing the horizontal and vertical frequency, amplitude, oscillation time, and correlation, it can detect the deformation of the transformer winding. The application has the characteristics of simple test circuit, strong detection signal, high voltage and high accuracy, and is suitable for transformer winding deformation fault detection.

Embodiment 1: The ground-to-ground stray capacitance C ₁ of the transformer 7, the bushing capacitance C ₀ and the leakage reactance oscillation circuit of the primary winding L _m to the secondary winding 3, the secondary winding 3 of the transformer 7 is short-circuited by the short-circuit wire 2 , the three-phase neutral point of the primary winding L _m of the transformer 7 is connected to the DC high-voltage generator 1, and the DC high-voltage generator 1 is grounded, and a protective resistor R is set between the DC high-voltage generator 1 and the short-circuit switch K ₁ , and the short-circuit switch K ₁ One end is electrically connected between the DC high voltage generator 1 and the primary winding L _m , the other end is grounded, and the DC high voltage generator 1 is connected to a 220V AC power supply. The first ends of the three phases of the primary winding L _m of the transformer 7 are suspended, or the first ends of the three phases of the primary winding L _m of the transformer 7 are electrically connected to the compensation capacitor 5 , and one end of the compensation capacitor 5 is grounded. The end screen of the bushing capacitor C ₀ of each phase of the primary winding L _m is electrically connected to a voltage dividing capacitor 6 , both ends of the voltage dividing capacitor 6 are connected to the waveform measurement and analysis device 4 , and the voltage dividing capacitor 6 is grounded.

Embodiment 2: The ground-to-ground stray capacitance C ₁ of the transformer 7, the bushing capacitance C ₀ and the excitation impedance oscillation circuit of the primary winding L _m to the secondary winding 3, the secondary winding 3 does not need to be short-circuited, and the primary winding of the transformer 7 The three-phase neutral point of L _m is connected to the DC high voltage generator 1, the DC high voltage generator 1 is grounded, the protection resistor R is set between the DC high voltage generator 1 and the short-circuit switch K ₁ , and one end of the short-circuit switch K ₁ is electrically connected to the DC high voltage Between the generator 1 and the primary winding L _m , the other end is grounded, and the DC high voltage generator 1 is connected to a 220V AC power supply. The first ends of the three phases of the primary winding L _m of the transformer 7 are suspended, or the first ends of the three phases of the primary winding L _m of the transformer 7 are electrically connected to the compensation capacitor 5 , and one end of the compensation capacitor 5 is grounded. The end screen of the bushing capacitor C ₀ of each phase of the primary winding L _m is electrically connected to a voltage dividing capacitor 6 , both ends of the voltage dividing capacitor 6 are connected to the waveform measurement and analysis device 4 , and the voltage dividing capacitor 6 is grounded.

A method for detecting deformation of a transformer winding by an oscillatory wave, comprising the following steps:

First, the DC high voltage generator 1 is connected to a 220V AC power supply, the DC high voltage generator 1 is electrically connected to the three-phase neutral point of the primary winding L _m of the transformer 7, and one end of the short circuit switch K ₁ is electrically connected to the DC high voltage generator 1 and the primary Between the windings L _m , the other end is grounded, a protective resistor R is set between the DC high voltage generator 1 and the short-circuit switch K ₁ , and the voltage dividing capacitor 6 is electrically connected to the end screen of the bushing capacitor C ₀ of each phase, and the voltage dividing capacitor 6 is grounded, and the waveform measurement and analysis device 4 is connected to both ends of the voltage dividing capacitor 6; in the method, the three-phase first ends of the primary winding L _m of the transformer 7 are all suspended in the air; or the ground stray capacitance C ₁ , the bushing capacitance C ₀ and the primary When the leakage reactance of the winding L _m to the secondary winding 3 or the duration of the oscillation wave of the excitation impedance oscillation circuit is less than 3 cycles, the three-phase first ends of the primary winding L _m of the transformer 7 are electrically connected to the compensation capacitor 5, and the compensation capacitor 5 One end is grounded. In the method, if the stray capacitance C ₁ to ground, the bushing capacitance C ₀ and the leakage reactance oscillation loop of the primary winding L _m to the secondary winding 3 are formed, the secondary winding 3 of the transformer 7 is short-circuited through the short-circuit wire 2;

Then DC voltage is charged to the primary winding L _m through the DC high voltage generator 1, and the short-circuit switch K ₁ is controlled to close, forming stray capacitance C ₁ to ground, bushing capacitance C ₀ and the leakage of the primary winding L _m to the secondary winding 3 Anti or excitation impedance oscillation circuit, the three-phase voltage response curve of the primary winding L _m is measured by the waveform measurement and analysis device 4;

Finally, according to the measured three-phase voltage response curve, analyze and compare the frequency, oscillation time, consistency, variance and mean difference of the three-phase voltage response curve of the three-phase voltage response curve to determine whether the transformer winding is deformed.

In this application, on the basis of using the leakage reactance or excitation impedance of the transformer winding and the stray capacitance of the capacitive bushing and the winding to the ground to form a ferromagnetic oscillation to detect the deformation of the winding, a DC voltage is applied to the neutral point connecting line of the transformer star winding Then ground it quickly, and measure the voltage response waveform of the loop. The loop consists of a DC high voltage generator 1, a protective resistor R, a short-circuit switch K ₁ , a short-circuit wire 2, a waveform measurement and analysis device 4, a compensation capacitor 5 and a voltage dividing capacitor 6 constitute.

This application skillfully utilizes the oscillating circuit formed between the leakage reactance or excitation impedance of the transformer and the capacitive bushing, the stray capacitance of the winding to the ground and the external compensation capacitor, and applies a DC voltage to the neutral point connecting line of the transformer star winding Then ground it quickly, and measure the voltage response waveform of the circuit. It has the characteristics of simple test circuit, strong detection signal, high voltage and high accuracy, and is suitable for latent fault detection of transformer winding deformation.

It should be noted that terms such as "comprising" or any other variant thereof are intended to cover a non-exclusive inclusion such that an article or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, Or also include elements inherent in such a process, method, article or apparatus.

The above descriptions are only specific implementation manners of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

It should be understood that the present application is not limited to what has been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims (8)

1. An oscillatory wave detection transformer winding deformation circuit is characterized in that it comprises a DC high-voltage power supply, the DC high-voltage power supply is electrically connected to the three-phase neutral point of the primary winding (L _m ) of the transformer (7), and the DC high-voltage power supply and the primary A short-circuit switch (K ₁ ) is provided between the windings (L _m ), one end of the short-circuit switch (K ₁ ) is electrically connected between the DC high-voltage power supply and the primary winding (L _m ), and the other end is grounded; the primary winding (L _m ) is provided with a bushing capacitor (C ₀ ) and a number of stray capacitors (C ₁ ) to ground, and the end screen of the bushing capacitor (C ₀ ) of each phase is electrically connected with a voltage dividing capacitor (6), Both ends of the voltage-dividing capacitor (6) are connected to the waveform measurement and analysis device (4), and the voltage-dividing capacitor (6) is grounded; after the primary winding (L _m ) is charged with DC voltage, close the short-circuit switch (K ₁ ), form the ground stray capacitance (C ₁ ), the bushing capacitance (C ₀ ) and the leakage reactance or excitation impedance oscillation loop from the primary winding (L _m ) to the secondary winding (3), through the waveform measurement and analysis device ( 4) Measure the three-phase voltage response curve of the primary winding (L _m ), and judge whether the transformer winding is deformed according to the three-phase voltage response curve. 2. The winding deformation circuit of an oscillatory wave detection transformer according to claim 1, characterized in that, the primary winding (L _m ) of the transformer (7) is a star winding. 3. The winding deformation circuit of an oscillatory wave detection transformer according to claim 1, characterized in that, the first ends of the three phases of the primary winding (L _m ) of the transformer (7) are all suspended in the air. 4. A kind of oscillation wave detection transformer winding deformation circuit according to claim 1, characterized in that, the three-phase first ends of the primary winding (L _m ) of the transformer (7) are electrically connected with compensation capacitors (5) , one end of the compensation capacitor (5) is grounded. 5. A kind of oscillatory wave detection transformer winding deformation circuit according to any one of claims 1-4, characterized in that, the secondary winding (3) of the transformer (7) is short-circuited by a short-circuit wire (2) . 6. A kind of oscillating wave detection transformer winding deformation circuit according to any one of claims 1-4, characterized in that, the DC high-voltage power supply comprises a DC high-voltage generator (1) connected to the power supply, and the DC high-voltage generator (1) Electrically connected to the three-phase neutral point of the primary winding (L _m ) of the transformer (7), the DC high voltage generator (1) is grounded, and one end of the short circuit switch (K ₁ ) is electrically connected to the DC high voltage generator (1 ) and the primary winding (L _m ). 7. The transformer winding deformation circuit for oscillatory wave detection according to claim 6, characterized in that the DC high voltage generator (1) is connected to a 220V AC power supply. 8 . The transformer winding deformation circuit for oscillatory wave detection according to claim 7 , characterized in that a protection resistor (R) is set between the DC high voltage generator ( 1 ) and the short circuit switch ( K ₁ ).