CN115389826A - Human body safety low-voltage direct-current step impact type transformer transformation ratio detection method - Google Patents

Abstract

The invention relates to a low-voltage direct-current step impulse type transformer transformation ratio detection method for human body safety, which comprises the steps of obtaining the relation between waveform parameters converted to a high-voltage side under the impulse excitation of unit step pulse of a transformer and related parameters of a transformer RLC passive network based on the related parameters and a transfer function of the transformer RLC passive network; acquiring a mathematical relation between waveform parameters deducted and converted to a high-voltage side under unit step pulse impact excitation of a mutual inductor; acquiring a mathematical relation between low-voltage side non-converted waveform parameters under unit step pulse impact excitation of the mutual inductor; obtaining a transformation ratio value of the mutual inductor; obtaining actual measurement parameters of secondary side output waveform of the mutual inductor, and actual measurement value R of direct resistance sum of winding coil and external lead thereof _l ' and fixed capacitance C ₂ '; and acquiring a transformation ratio estimation value of the mutual inductor. The method deduces the current transformer and the electricity of the transformer substation by means of the low-voltage direct current in the human body bearing rangeThe transformer transformation ratio detection technology of the voltage transformer.

Description

A human-safe low-voltage DC step-impact transformer transformation ratio detection method

technical field

The invention relates to the technical field of transformer detection, in particular to a human-safe low-voltage DC step-impact transformer transformation ratio detection method.

Background technique

In the substation engineering site, the transformer ratio detection is a basic and important work, which is directly related to the correct operation of the secondary device. At this stage, due to the problem of series and parallel connection on the primary side of the transformer and the tap problem on the secondary side , the transformation ratio of transformers, especially the transformation ratio of current transformers, is not unique, and the transformation ratio used by transformers needs to be tested on site during equipment acceptance.

At this stage, the detection of the transformation ratio of the transformer is actually detected by feeding a large voltage or a large current, and the voltage or current often needs to be boosted by a booster device or a large current generator, which has high personal risks, expensive equipment, heavy weight, and is easily damaged. In order to overcome the on-site problems of high personal risk, expensive equipment, heavy weight, and easy damage in transformer ratio detection, this patent proposes a human-safe low-voltage DC step-impact transformer ratio detection method.

Contents of the invention

The invention provides a human-safe low-voltage DC step-impact transformer transformation ratio detection method, which solves the problems of high personal risk, expensive equipment, heavy weight and easy damage to operators in the existing transformation ratio detection of transformers. question.

The present invention solves its technical problem and realizes by taking the following technical solutions:

A method for detecting the transformation ratio of a low-voltage DC step-impact transformer that is safe for human body, the specific steps are as follows:

Step 1. Based on the relevant parameters and the transfer function of the RLC passive network of the transformer, the relationship between the waveform parameters converted to the high-voltage side under the unit step pulse shock excitation of the transformer and the relevant parameters of the RLC passive network of the transformer is obtained;

Step 2. Based on the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, obtain the waveform converted to the high voltage side under the unit step pulse impulse excitation of the transformer Mathematical relationship between parameters;

Step 3. Based on obtaining the mathematical relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer, obtain the unconverted waveform parameters of the low voltage side under the unit step pulse impulse excitation of the transformer. The mathematical relationship between ;

Step 4. Based on the obtained mathematical relationship between the unconverted waveform parameters on the low-voltage side under the excitation of the unit step pulse shock of the transformer, the transformation ratio value of the transformer is obtained;

Step 5, based on the attenuated oscillation waveform of the secondary side output of the transformer, the measured parameters of the output waveform of the secondary side of the transformer are obtained;

Step 6. Obtain the measured value R _l ' of the sum of the direct resistance of the secondary side winding coil of the transformer and its external wires;

Step 7. Obtain the fixed capacitance C ₂ ' on the secondary side of the transformer by making prefabricated wires on the secondary side of the transformer;

Step 8. Using the obtained measured parameters of the output waveform of the secondary side of the transformer, the measured value R _l ' of the sum of the direct resistance of the secondary winding coil of the transformer and its external wires, and the fixed capacitance C ₂ ' of the secondary side of the transformer, obtain Transformation ratio estimated value of transformer;

Preferably, the relevant parameters based on the transformer RLC passive network in step 1 include high-voltage side inductance L _h , high-voltage side resistance R _h , low-voltage side converted inductance L _l , low-voltage side converted resistance R _l , excitation Reactance M _m , excitation resistance R _m , primary side wire capacitance C ₁ , secondary side wire capacitance C ₂ , primary side applied experimental voltage ui and secondary side output voltage u0;

The transfer function of the RLC passive network of the transformer is obtained by using the relevant parameters of the RLC passive network of the transformer obtained above, specifically:

Obtain the complex impedance Z ₁ , Z ₂ and Z ₃ of the branch corresponding to the RLC passive network of the transformer, the specific formula is as follows:

Z ₂ =(L _h +L _l )s+R _h +R _l ;

In the formula:

s represents the complex frequency,

Z ₁ , Z ₂ , and Z ₃ respectively represent the complex impedance of the corresponding branch;

By obtaining the complex impedances Z ₁ , Z ₂ and Z ₃ of the corresponding branches of the transformer RLC passive network, the relationship can be obtained as follows:

Preferably, in the step 1, the relationship between the waveform parameters converted to the high-voltage side and the relevant parameters of the RLC passive network of the transformer under the unit step pulse shock excitation of the transformer is obtained, including:

The input waveform of the transformer is a unit step pulse, that is, the form satisfies u _i (t)=u(t), where

可得具体公式如下：According to the Laplace transform formula

The specific formula can be obtained as follows:

According to the Laplace transform comparison table, the above formula satisfies the relation

In the formula:

Damping ratio

Natural frequency

下，可得进行拉氏反变换的时域表达式为：According to the Laplace transform comparison table, the above relation is satisfied in the form

Under the following conditions, the time-domain expression for inverse Laplace transform can be obtained as:

In the formula:

The relationship between the waveform parameters converted to the high-voltage side and the relevant parameters of the RLC passive network of the transformer under the unit step pulse impulse excitation of the transformer is obtained as follows:

Using the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer can be obtained , including amplitude A, angular velocity ω and decay time constant τ, the specific formula is as follows:

Preferably, in the step 2, the parameters related to the passive network of the transformer RLC include the high-voltage side resistance R _h , the converted resistance R ₁ of the low-voltage side, and the secondary-side wire capacitance C ₂ ;

The waveform parameters converted to the high-voltage side based on the obtained transformer unit step pulse shock excitation include the amplitude A, angular velocity ω, and decay time constant τ of the output waveform of the transformer converted to the high-voltage side,

Using the amplitude A, angular velocity ω, decay time constant τ, high-voltage side resistance R _h , low-voltage side converted resistance R _l and secondary-side wire capacitance C ₂ of the output waveform converted from the transformer to the high-voltage side, the transformer unit can be obtained The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced under step pulse shock excitation as follows:

The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced by using the unit step pulse impulse excitation of the transformer,

Since R _h <R _l '; get R _h <<N ² R _l '=R _l , and then deduce that R _h +R _l ≈R _l , the relationship is as follows:

According to the above relationship, the relationship can be deduced as follows:

Preferably, obtaining the mathematical relationship between the unconverted waveform parameters on the low voltage side under the unit step pulse impulse excitation of the transformer in the step 3 includes using the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the mutual inductance The corresponding relationship formulas A=A'N, ω=ω' and τ=τ' of the waveform parameters converted to the low-voltage side under the unit step pulse shock excitation of the device can be obtained as follows:

In the formula:

A' is the amplitude of the output waveform at the low-voltage side of the transformer;

ω' is the angular frequency of the output waveform at the low-voltage side of the transformer;

C ₂ ' is the actual capacitance of the low-voltage side of the transformer;

N is the transformation ratio of the transformer;

τ' is the decay time constant of the output waveform at the low-voltage side of the transformer;

R _l ' is the actual resistance of the low-voltage side of the transformer;

Preferably, in the step 4, based on the amplitude of the low-voltage output waveform obtained under the excitation of the unit step pulse shock of the transformer, the specific calculation formula for obtaining the transformation ratio of the low-voltage side of the transformer is as follows:

Preferably, the oscillating waveform attenuated by the secondary side output of the transformer in the step 5 includes extracting three maximum values of the attenuated oscillating waveform output at the secondary side of the three transformers, which are respectively Y ₁ , Y ₂ , Y ₃ and Y ₁ Time difference t ₁ with Y ₂ , time difference t ₂ between Y ₂ and Y ₃ ,

The acquisition of measured parameters of the output waveform of the secondary side of the transformer includes the amplitude A' of the output waveform of the low-voltage side of the transformer, the angular frequency ω' of the output waveform of the low-voltage side of the transformer, and the decay time constant τ' of the output waveform of the low-voltage side of the transformer. ,

The three maximum values of the attenuated oscillating waveforms output by the secondary side of the three transformers are Y ₁ , Y ₂ , Y ₃ , and the time difference t ₁ between Y ₁ and Y ₂ , and the time difference t ₂ between Y ₂ and Y ₃ Perform calculations to obtain the amplitude A' of the output waveform at the low-voltage side of the transformer, the angular frequency ω' of the output waveform at the low-voltage side of the transformer, and the decay time constant τ' of the output waveform at the low-voltage side of the transformer. The specific formulas are as follows:

Preferably, in the step 8, the obtained transformer secondary side output waveform measured parameters, the measured value R _l ' of the direct resistance sum of the transformer secondary side winding coil and its external wire and the transformer secondary side fixed capacitance C ₂ ', the specific calculation formula for obtaining the transformation ratio estimation value of the transformer is as follows:

Advantage and positive effect of the present invention are:

The invention relates to a method for detecting the transformation ratio of a low-voltage DC step-impact transformer that is safe for the human body. The transformation ratio detection technology of the transformer has the following advantages:

1. With the help of low-voltage direct current within the range of human body tolerance, this patent derives the transformer ratio detection technology for current transformers and voltage transformers in substations;

2. This patented technology has changed the method of on-site transformation ratio testing with the help of a booster device or a large current generator, and changed the current situation of high personal risk, expensive equipment, heavy weight, and easy damage in the field of transformation ratio detection, making the on-site The variable ratio detection work becomes simple and has no personal risk;

3. It has changed the current situation that the current substation transformer acceptance equipment has heavy assets, and provided a reference for the traditional on-site acceptance process to be lean, technological, and high-end;

4. The patented method overcomes the fact that the transformation ratio detection of the current transformer adopts the method of inputting a large voltage or a large current for actual detection, and the voltage or current often needs to use a booster device or a large current generator, which has high personal risks, expensive equipment, and heavy weight. Large and easily damaged, you can quickly and safely obtain the transformation ratio value of the transformer.

Description of drawings

Fig. 1 is the method flow chart of the low-voltage DC step impact transformer ratio detection of human body safety of the present invention;

Fig. 2 is the RLC input and output passive network diagram of transformer;

Fig. 3 is the RLC complex impedance passive network diagram of transformer;

Fig. 4 is the oscillating waveform diagram of transformer secondary side output attenuation;

Fig. 5 is the actual measured value diagram of the direct resistance sum of the low-voltage side winding coil of the transformer and its external wire;

Figure 6 is a schematic diagram of making prefabricated wires on the secondary side of the transformer.

Detailed ways

The present invention provides a human-safe low-voltage DC step impact transformer ratio detection method, as shown in Figure 1, the specific steps are as follows:

Step 1. Based on the relevant parameters and the transfer function of the RLC passive network of the transformer, the relationship between the waveform parameters converted to the high-voltage side under the unit step pulse shock excitation of the transformer and the relevant parameters of the RLC passive network of the transformer is obtained;

In this step, as shown in Figure 2, the relevant parameters of the transformer-based RLC passive network include high-voltage side inductance L _h , high-voltage side resistance R _h , low-voltage side converted inductance L _l , low-voltage side converted Resistor R _l , excitation reactance M _m , excitation resistance R _m , primary side wire capacitance C ₁ , secondary side wire capacitance C ₂ , primary side applied experimental voltage ui and secondary side output voltage u0;

The transfer function of the RLC passive network of the transformer is obtained by using the relevant parameters of the RLC passive network of the transformer obtained above, specifically:

Obtain the complex impedance Z ₁ , Z ₂ and Z ₃ of the branch corresponding to the RLC passive network of the transformer, the specific formula is as follows:

Z ₂ =(L _h +L _l )s+R _h +R _l ;

In the formula:

s represents the complex frequency,

Z ₁ , Z ₂ , and Z ₃ respectively represent the complex impedances of the corresponding branches; by obtaining the complex impedances Z ₁ , Z ₂ and Z ₃ of the corresponding branches of the transformer RLC passive network, the relationship can be obtained as follows:

In this step, the acquisition of waveform parameters converted to the high-voltage side under unit step pulse shock excitation of the transformer includes,

The input waveform of the transformer is a unit step pulse, that is, the form satisfies u _i (t)=u(t), where

可得具体公式如下：According to the Laplace transform formula

The specific formula can be obtained as follows:

According to the Laplace transform comparison table, the above formula satisfies the relation

In the formula:

Damping ratio

Natural frequency

下，可得进行拉氏反变换的时域表达式为：According to the Laplace transform comparison table, the above relation is satisfied in the form

Under the following conditions, the time-domain expression for inverse Laplace transform can be obtained as:

In the formula:

The relationship between the waveform parameters converted to the high-voltage side and the relevant parameters of the RLC passive network of the transformer under the unit step pulse impulse excitation of the transformer is obtained as follows:

Using the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer can be obtained , including amplitude A, angular velocity ω and decay time constant τ, the specific formula is as follows:

Step 2. Based on the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, obtain the waveform converted to the high voltage side under the unit step pulse impulse excitation of the transformer Mathematical relationship between parameters;

In this step, the parameters related to the passive network of the transformer RLC include the high voltage side resistance R _h , the low voltage side converted resistance R ₁ and the secondary side wire capacitance C ₂ ;

The waveform parameters converted to the high-voltage side based on the obtained transformer unit step pulse shock excitation include the amplitude A, angular velocity ω, and decay time constant τ of the output waveform of the transformer converted to the high-voltage side,

Using the amplitude A, angular velocity ω, decay time constant τ, high-voltage side resistance R _h , low-voltage side converted resistance R _l and secondary-side wire capacitance C ₂ of the output waveform converted from the transformer to the high-voltage side, the transformer unit can be obtained The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced under step pulse shock excitation as follows:

The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced by using the unit step pulse impulse excitation of the transformer,

Since R _h <R _l '; get R _h <<N ² R _l '=R _l , and then deduce that R _h +R _l ≈R _l , the relationship is as follows:

According to the above relationship, the relationship can be deduced as follows:

Step 3. Based on obtaining the mathematical relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer, obtain the unconverted waveform parameters of the low voltage side under the unit step pulse impulse excitation of the transformer. The mathematical relationship between :

In this step, said obtaining the mathematical relationship between the unconverted waveform parameters on the low voltage side under the unit step pulse impulse excitation of the transformer includes using the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the transformer The corresponding relational expressions A=A'N, ω=ω' and τ=τ' of the waveform parameters converted to the low-voltage side under unit step pulse shock excitation can be obtained as follows:

In the formula:

A' is the amplitude of the output waveform at the low-voltage side of the transformer;

ω' is the angular frequency of the output waveform at the low-voltage side of the transformer;

C ₂ ' is the actual capacitance of the low-voltage side of the transformer;

N is the transformation ratio of the transformer;

τ' is the decay time constant of the output waveform at the low-voltage side of the transformer;

R _l ' is the actual resistance of the low-voltage side of the transformer;

Step 4. Based on the obtained mathematical relationship between the unconverted waveform parameters on the low-voltage side under the excitation of the unit step pulse shock of the transformer, the transformation ratio value of the transformer is obtained;

The specific calculation formula is as follows:

Step 5, based on the attenuated oscillation waveform of the secondary side output of the transformer, the measured parameters of the output waveform of the secondary side of the transformer are obtained;

In this step, as shown in FIG. 3 , the attenuated oscillating waveform at the secondary side of the transformer includes extracting three maximum values of the attenuated oscillating waveform at the secondary side of the transformer, respectively Y ₁ , Y ₂ , Y ₃ and the time difference t ₁ between Y ₁ and Y ₂ , the time difference t ₂ between Y ₂ and Y ₃ ,

The acquisition of measured parameters of the output waveform of the secondary side of the transformer includes the amplitude A' of the output waveform of the low-voltage side of the transformer, the angular frequency ω' of the output waveform of the low-voltage side of the transformer, and the decay time constant τ' of the output waveform of the low-voltage side of the transformer. ,

The three maximum values of the attenuated oscillating waveforms output by the secondary side of the three transformers are Y ₁ , Y ₂ , Y ₃ , and the time difference t ₁ between Y ₁ and Y ₂ , and the time difference t ₂ between Y ₂ and Y ₃ Perform calculations to obtain the amplitude A' of the output waveform at the low-voltage side of the transformer, the angular frequency ω' of the output waveform at the low-voltage side of the transformer, and the decay time constant τ' of the output waveform at the low-voltage side of the transformer. The specific formulas are as follows:

Step 6. Obtain the measured value R _l ' of the sum of the direct resistance of the secondary side winding coil of the transformer and its external wires;

Step 7. Obtain the fixed capacitance C ₂ ' on the secondary side of the transformer by making prefabricated wires on the secondary side of the transformer;

Step 8. Using the obtained measured parameters of the output waveform of the secondary side of the transformer, the measured value R _l ' of the sum of the direct resistance of the secondary winding coil of the transformer and its external wires, and the fixed capacitance C ₂ ' of the secondary side of the transformer, obtain Transformation ratio estimated value of transformer;

The specific calculation formula is as follows:

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific installation and working process of the above-described device can refer to the corresponding process in the above-mentioned embodiments, which will not be repeated here.

First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of examples, but all descriptions are only for illustration, and should not be construed as forming any limitation on the present invention . In addition, any single technical feature described or implied in the embodiments mentioned herein can still be combined or deleted between these technical features (or their equivalents), so as to obtain Further other embodiments of the invention mentioned directly in .

It should be noted that the terminology used here is only for describing specific implementations, and is not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover a non-exclusive inclusion, for example, includes A process, method, system, product, or device that is a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other step or unit.

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, so the present invention includes and is not limited to the embodiments described in the specific implementation, and those skilled in the art according to the technology of the present invention Other implementations derived from the scheme also belong to the protection scope of the present invention.

Claims (8)

1. A low-voltage DC step-impact transformer transformation ratio detection method for human safety, characterized in that: the specific steps are as follows: Step 1. Based on the relevant parameters and the transfer function of the RLC passive network of the transformer, the relationship between the waveform parameters converted to the high-voltage side under the unit step pulse shock excitation of the transformer and the relevant parameters of the RLC passive network of the transformer is obtained; Step 2. Based on the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, obtain the waveform converted to the high voltage side under the unit step pulse impulse excitation of the transformer Mathematical relationship between parameters; Step 3. Based on obtaining the mathematical relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer, obtain the unconverted waveform parameters of the low voltage side under the unit step pulse impulse excitation of the transformer. The mathematical relationship between ; Step 4. Based on the obtained mathematical relationship between the unconverted waveform parameters on the low-voltage side under the excitation of the unit step pulse shock of the transformer, the transformation ratio value of the transformer is obtained; Step 5, based on the attenuated oscillation waveform of the secondary side output of the transformer, the measured parameters of the output waveform of the secondary side of the transformer are obtained; Step 6. Obtain the measured value R _l ' of the sum of the direct resistance of the secondary side winding coil of the transformer and its external wires; Step 7. Obtain the fixed capacitance C ₂ ' on the secondary side of the transformer by making prefabricated wires on the secondary side of the transformer; Step 8. Using the obtained measured parameters of the output waveform of the secondary side of the transformer, the measured value R _l ' of the sum of the direct resistance of the secondary winding coil of the transformer and its external wires, and the fixed capacitance C ₂ ' of the secondary side of the transformer, obtain Transformation ratio estimated value of transformer. 2. The low-voltage DC step impact transformer transformation ratio detection method of human body safety according to claim 1, characterized in that: in the step 1, the relevant parameters based on the transformer RLC passive network include the high-voltage side inductance L _h , high-voltage side resistance R _h , low-voltage side converted inductance L _l , low-voltage side converted resistance R _l , excitation reactance M _m , excitation resistance R _m , primary-side wire capacitance C ₁ , secondary-side wire capacitance C ₂ , the experimental voltage ui applied on the primary side and the output voltage u0 on the secondary side; The transfer function of the RLC passive network of the transformer is obtained by using the relevant parameters of the RLC passive network of the transformer obtained above, specifically: Obtain the complex impedance Z ₁ , Z ₂ and Z ₃ of the branch corresponding to the RLC passive network of the transformer, the specific formula is as follows:

Z ₂ =(L _h +L _l )s+R _h +R _l ;

In the formula: s represents the complex frequency, Z ₁ , Z ₂ , and Z ₃ respectively represent the complex impedance of the corresponding branch; By obtaining the complex impedances Z ₁ , Z ₂ and Z ₃ of the corresponding branches of the transformer RLC passive network, the relationship can be obtained as follows:

3. The human body safe low-voltage DC step-impact transformer transformation ratio detection method according to claim 1, characterized in that: in the step 1, the waveform converted to the high-voltage side under the unit step pulse impulse excitation of the transformer is obtained The relationship of the parameters with the relevant parameters of the transformer RLC passive network includes, The input waveform of the transformer is a unit step pulse, that is, the form satisfies u _i (t)=u(t), where

According to the Laplace transform formula

The specific formula can be obtained as follows:

According to the Laplace transform comparison table, the above formula satisfies the relation

In the formula: Damping ratio

Natural frequency

According to the Laplace transform comparison table, the above relation is satisfied in the form

Under the following conditions, the time-domain expression for inverse Laplace transform can be obtained as:

In the formula:

The relationship between the waveform parameters converted to the high-voltage side and the relevant parameters of the RLC passive network of the transformer under the unit step pulse impulse excitation of the transformer is obtained as follows:

Using the relationship between the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer and the relevant parameters of the RLC passive network of the transformer, the waveform parameters converted to the high voltage side under the unit step pulse impulse excitation of the transformer can be obtained , including amplitude A, angular velocity ω and decay time constant τ, the specific formula is as follows:

4. The human body safe low-voltage DC step impact transformer transformation ratio detection method according to claim 1, characterized in that: in the step 2, the relevant parameters of the RLC passive network of the transformer include high-voltage side resistance R _h , low-voltage The converted resistance R _l on the side and the capacitance C ₂ on the secondary side wire; The waveform parameters converted to the high-voltage side based on the obtained transformer unit step pulse shock excitation include the amplitude A, angular velocity ω, and decay time constant τ of the output waveform of the transformer converted to the high-voltage side, Using the amplitude A, angular velocity ω, decay time constant τ, high-voltage side resistance R _h , low-voltage side converted resistance R _l and secondary-side wire capacitance C ₂ of the output waveform converted from the transformer to the high-voltage side, the transformer unit can be obtained The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced under step pulse shock excitation as follows:

The mathematical relationship between the waveform parameters converted to the high-voltage side is deduced by using the unit step pulse impulse excitation of the transformer, Since R _h <R _l '; get R _h <<N ² R _l '=R _l , and then deduce that R _h +R _l ≈R _l , the relationship is as follows:

According to the above relationship, the relationship can be deduced as follows:

5. The human-safe low-voltage DC step-impact transformer transformation ratio detection method according to claim 1, characterized in that: in the step 3, the unconverted waveform on the low-voltage side under the unit step pulse impulse excitation of the transformer is obtained The mathematical relationship between parameters includes the corresponding relationship between the waveform parameters converted to the high-voltage side under the unit step pulse impulse excitation of the transformer and the waveform parameters converted to the low-voltage side under the unit step pulse impulse excitation of the transformer A=A'N , ω=ω' and τ=τ' can be obtained as follows:

In the formula: A' is the amplitude of the output waveform at the low-voltage side of the transformer; ω' is the angular frequency of the output waveform at the low-voltage side of the transformer; C ₂ ' is the actual capacitance of the low-voltage side of the transformer; N is the transformation ratio of the transformer; τ' is the decay time constant of the output waveform at the low-voltage side of the transformer; R _l ' is the actual resistance of the low-voltage side of the transformer. 6. The human body safe low-voltage DC step-impact transformer transformation ratio detection method according to claim 1, characterized in that: in the step 4, based on the obtained transformer unit step pulse shock excitation, the low-voltage output waveform Amplitude, the specific calculation formula for obtaining transformer low-voltage side transformation ratio is as follows:

7. The human body safe low-voltage DC step impact transformer transformation ratio detection method according to claim 1, characterized in that: in the step 5, the attenuated oscillation waveform of the secondary side output of the transformer includes extracting three transformers The three maximum values of the oscillatory waveform attenuated by the secondary side output are Y ₁ , Y ₂ , Y ₃ and the time difference t ₁ between Y ₁ and Y ₂ , and the time difference t ₂ between Y ₂ and Y ₃ , The acquisition of measured parameters of the output waveform of the secondary side of the transformer includes the amplitude A' of the output waveform of the low-voltage side of the transformer, the angular frequency ω' of the output waveform of the low-voltage side of the transformer, and the decay time constant τ' of the output waveform of the low-voltage side of the transformer. , The three maximum values of the attenuated oscillating waveforms output by the secondary side of the three transformers are Y ₁ , Y ₂ , Y ₃ , and the time difference t ₁ between Y ₁ and Y ₂ , and the time difference t ₂ between Y ₂ and Y ₃ Perform calculations to obtain the amplitude A' of the output waveform at the low-voltage side of the transformer, the angular frequency ω' of the output waveform at the low-voltage side of the transformer, and the decay time constant τ' of the output waveform at the low-voltage side of the transformer. The specific formulas are as follows:

8. The method for detecting the transformation ratio of a low-voltage direct current step impact transformer with human safety according to claim 1, characterized in that: in the step 8, the obtained transformer secondary side output waveform measured parameters, transformer secondary The actual measured value R _l ' of the sum of the direct resistance of the secondary winding coil and its external wires and the fixed capacitance C ₂ ' of the secondary side of the transformer, the specific calculation formula for obtaining the estimated value of the transformation ratio of the transformer is as follows:

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