Online monitoring method and system for deformation of distribution transformer winding

Abstract

The invention discloses an on-line monitoring method and system for deformation of a distribution transformer winding, and the method comprises the steps: collecting three-phase current and voltage signals of a primary side and a secondary side of a distribution transformer when the distribution transformer operates with a load, carrying out the fast Fourier transform, obtaining the current and voltage phasors of the primary side and the secondary side, and carrying out the calculation of the current and voltage phasors; the method comprises the steps of calculating equivalent three-phase parameters according to current and voltage phasors of a primary side and a secondary side, performing disturbance processing on the equivalent three-phase parameters to obtain disturbance three-phase parameters, constructing a resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbance three-phase parameters, and solving the equation to obtain a three-phase short-circuit reactance value. And if the three-phase short-circuit reactance value is abnormal, a winding deformation alarm prompt is displayed. Therefore, when the distribution transformer runs, the short-circuit reactance of the transformer can be measured only by sampling the current and the voltage once without adjusting the load of the transformer, so that the deformation of the winding can be quickly and accurately judged, and the deformation monitoring efficiency of the transformer winding is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution equipment operation status monitoring, and more specifically, to an online monitoring method and system for winding deformation of a distribution transformer. Background Art

[0002] As a key electrical equipment in the power distribution system, the transformer plays an extremely important role in the transmission and conversion of electric energy. However, as the transformer operates for a long time, its performance may gradually deteriorate, which may eventually cause failures or accidents. The occurrence of transformer failure will not only interfere with the normal operation of the power grid, but may also cause significant damage to the power grid.

[0003] Among many transformer failure cases, the proportion of winding and core failures is about 60%, which poses a serious threat to the safety of the transformer itself and the normal operation of the entire power system. Transformer failure does not occur suddenly, but is a gradual accumulation process. Therefore, real-time monitoring of transformers, early detection of possible failure risks, and providing necessary operating information for transformer maintenance have become an important issue facing the power industry.

[0004] The deformation of transformer windings is an important indicator of performance degradation and failure. Although the degree of winding deformation is relatively light in most cases, due to the cumulative effect, the deformation of the winding will continue to increase, and eventually the inter-turn insulation will be damaged and form an inter-turn short circuit.

[0005] At present, general conventional experiments cannot effectively detect the deformation of windings. Most winding deformation detection methods are time-consuming and labor-intensive and require power outages, which brings inconvenience to the normal operation of the power system; the existing transformer winding online monitoring method requires continuous measurement of voltage and current twice under different loads, which has poor real-time performance and low efficiency.

[0006] Based on this, how to improve the monitoring efficiency of distribution transformer winding deformation is a problem that needs to be solved. Summary of the invention

[0007] In view of the above problems, the present application provides an online monitoring method and system for the deformation of the windings of a distribution transformer, so as to complete the monitoring of the deformation of the windings of the distribution transformer under the primary voltage and current measurement, thereby improving the monitoring efficiency of the deformation of the windings of the distribution transformer.

[0008] In order to achieve the above objectives, the specific plan is proposed as follows:

[0009] An online monitoring method for winding deformation of a distribution transformer, comprising:

[0010] When the distribution transformer is running under load, collecting the three-phase voltage signal of the primary side of the distribution transformer, the three-phase voltage signal of the secondary side of the distribution transformer, the three-phase current signal of the primary side of the distribution transformer, and the three-phase current signal of the secondary side of the distribution transformer;

[0011] Performing fast Fourier transform on the three-phase voltage signal on the primary side, the three-phase voltage signal on the secondary side, the three-phase current signal on the primary side, and the three-phase current signal on the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor;

[0012] When the connection group of the distribution transformer is Yyn0, Yd11 or YNd11, the equivalent three-phase parameters are calculated according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor;

[0013] Processing the disturbance of the equivalent three-phase parameters to obtain the disturbed three-phase parameters;

[0014] Constructing a resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbance three-phase parameters, and solving the resistance reactance matrix equation to obtain a three-phase short-circuit reactance value of the distribution transformer;

[0015] The three-phase short-circuit reactance value is displayed, and if the three-phase short-circuit reactance value is abnormal, a winding deformation alarm prompt of the distribution transformer is displayed.

[0016] Optionally, calculating equivalent three-phase parameters according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor includes:

[0017] Use the following formula to calculate the equivalent three-phase parameters:

[0018]

[0019] in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

[0020] Optionally, the equivalent three-phase parameter disturbance processing is performed to obtain the disturbed three-phase parameter, including:

[0021] right Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. ;

[0022] right The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B ;

[0023] right The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the voltage C phase imaginary part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

[0024] Optionally, constructing a resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbance three-phase parameters, and solving the resistance reactance matrix equation to obtain a three-phase short-circuit reactance value of the distribution transformer includes:

[0025] The resistance reactance matrix equation is constructed using the following formula:

[0026]

[0027] in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the winding on the secondary side converted to the primary side;

[0028] Solving the resistance reactance matrix equation, the short-circuit reactance value of phase A of the distribution transformer is obtained as The short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

[0029] Optionally, the method further includes:

[0030] When the connection group of the distribution transformer is Dyn11, the primary side current phasor is used as the primary side line current phasor, and the primary side line current phasor is converted into a phase current as a new primary side current phasor;

[0031] Equivalent three-phase parameters are calculated according to the primary-side voltage phasor, the secondary-side voltage phasor, the primary-side current phasor, and the secondary-side current phasor.

[0032] An online monitoring system for the deformation of a distribution transformer winding comprises a signal acquisition unit, an arithmetic logic unit, an LCD display unit, a voltage sampling circuit, a current sampling circuit, two voltage transformers and two current transformers, wherein the two voltage transformers are respectively connected to the primary side and the secondary side of a three-phase distribution transformer, one current transformer is connected between a high-voltage bus and the distribution transformer, and the other current transformer is connected between the distribution transformer and a low-voltage bus, the two voltage transformers are connected to the voltage sampling circuit, the two current transformers are connected to the current sampling circuit, the output end of the voltage sampling circuit and the output end of the current sampling circuit are both connected to the input end of the signal acquisition unit, and the output end of the signal acquisition unit is connected to the LCD display unit through the arithmetic logic unit;

[0033] The signal acquisition unit is used to collect the three-phase voltage signal of the primary side of the distribution transformer, the three-phase voltage signal of the secondary side of the distribution transformer, the three-phase current signal of the primary side of the distribution transformer, and the three-phase current signal of the secondary side of the distribution transformer when the distribution transformer is running under load;

[0034] The arithmetic logic unit is used to perform fast Fourier transform on the three-phase voltage signal of the primary side, the three-phase voltage signal of the secondary side, the three-phase current signal of the primary side, and the three-phase current signal of the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor; when the connection group of the distribution transformer is Yyn0, Yd11, or YNd11, according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor, calculate the equivalent three-phase parameters, perform disturbance processing on the equivalent three-phase parameters, obtain the disturbed three-phase parameters, construct the resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbed three-phase parameters, and solve the resistance reactance matrix equation to obtain the three-phase short-circuit reactance value of the distribution transformer;

[0035] The LCD display unit is used to display the three-phase short-circuit reactance value, and if the three-phase short-circuit reactance value is abnormal, it will display the winding deformation alarm prompt of the distribution transformer.

[0036] Optionally, the arithmetic logic unit includes:

[0037] The equivalent three-phase parameter calculation unit is used to calculate the equivalent three-phase parameters using the following formula:

[0038]

[0039] in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

[0040] Optionally, the arithmetic logic unit further includes:

[0041] The first disturbance superposition unit is used to Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. ;

[0042] The second disturbance superposition unit is used to The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B ;

[0043] The third disturbance superposition unit is used to The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase C ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

[0044] Optionally, the arithmetic logic unit further includes:

[0045] The resistance-reactance matrix equation building unit is used to build the resistance-reactance matrix equation using the following formula:

[0046]

[0047] in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the winding on the secondary side converted to the primary side;

[0048] The short-circuit reactance value solving unit is used to solve the resistance reactance matrix equation to obtain the short-circuit reactance value of phase A of the distribution transformer. The short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

[0049] Optionally, the system further includes:

[0050] A current phasor conversion unit is used to, when the connection group of the distribution transformer is Dyn11, use the primary side current phasor as the primary side line current phasor, convert the primary side line current phasor into a phase current as a new primary side current phasor, and calculate equivalent three-phase parameters based on the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor.

[0051] By means of the above technical scheme, the present application collects the three-phase current and voltage signals on the primary and secondary sides of the distribution transformer when the distribution transformer is running with load, and performs fast Fourier transform to obtain the current and voltage phasors on the primary and secondary sides, calculates the equivalent three-phase parameters according to the current and voltage phasors on the primary and secondary sides, and performs disturbance processing on the equivalent three-phase parameters to obtain the disturbed three-phase parameters, constructs the resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbed three-phase parameters, solves the equation to obtain the three-phase short-circuit reactance value, and displays the winding deformation alarm prompt if the three-phase short-circuit reactance value is abnormal. It can be seen that when the distribution transformer is running, it only needs to sample the current and voltage once, and there is no need to adjust the load of the transformer to measure the short-circuit reactance of the transformer, so as to quickly and accurately judge the winding deformation, thereby improving the efficiency of transformer winding deformation monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0053] Figure 1 A system architecture diagram for realizing online monitoring of winding deformation of a distribution transformer provided in an embodiment of the present application;

[0054] Figure 2 An electrical schematic diagram of online monitoring of winding deformation of a distribution transformer provided in an embodiment of the present application;

[0055] Figure 3 A schematic diagram of a process for realizing online monitoring of winding deformation of a distribution transformer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] Figure 1 A system architecture for realizing an online monitoring system for the deformation of a distribution transformer winding provided in an embodiment of the present application, such as Figure 1 As shown, the system architecture may include:

[0058] Signal acquisition unit 10, arithmetic logic unit 20, LCD display unit 30, voltage sampling circuit 01 and current sampling circuit 02.

[0059] Specifically, the voltage sampling circuit 01 can monitor the voltage of the sampled distribution transformer, and the current sampling circuit 02 can monitor the current of the sampled distribution transformer. The distribution transformer can be a three-phase distribution transformer with a connection group of Yyn0. Based on this, the online monitoring system also includes two voltage transformers and two current transformers. The relationship between the two voltage transformers and the two current transformers and the distribution transformer is as follows: Figure 2 As shown, two voltage transformers are connected to the primary side and the secondary side of the distribution transformer respectively, the primary side is connected to the voltage transformer TV1, the secondary side is connected to the voltage transformer TV2, the current transformer TA1 is connected between the high-voltage bus and the distribution transformer T, and the current transformer TA2 is connected between the distribution transformer T and the low-voltage bus. Both voltage transformers are connected to the voltage sampling circuit 01, and both current transformers are connected to the current sampling circuit 02. The output end of the voltage sampling circuit 01 and the output end of the current sampling circuit 02 are connected to the input end of the signal acquisition unit 10, and the output end of the signal acquisition unit 10 is connected to the LCD display unit 30 through the arithmetic logic unit 20.

[0060] based on Figure 1 The system architecture shown, Figure 2 A schematic diagram of a flow chart of an online monitoring method for a distribution transformer winding deformation provided by an embodiment of the present application is shown, referring to Figure 2 , the process may include:

[0061] Step S110: When the distribution transformer is running with load, collect the three-phase voltage signal on the primary side, the three-phase voltage signal on the secondary side, the three-phase current signal on the primary side, and the three-phase current signal on the secondary side of the distribution transformer.

[0062] Specifically, the signal acquisition unit 10 can sample the current and voltage signals of the primary and secondary sides of the distribution transformer T when the distribution transformer T is running with load through the voltage transformer (TV1 and TV2) and the current transformer (TA1 and TA2).

[0063] Furthermore, the signal acquisition unit 10 may send the sampled values ​​to the arithmetic logic unit 20 .

[0064] Step S120, perform fast Fourier transform on the three-phase voltage signal on the primary side, the three-phase voltage signal on the secondary side, the three-phase current signal on the primary side, and the three-phase current signal on the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor.

[0065] Among them, the primary side voltage phasor is expressed as , , , the secondary voltage phasor is expressed as , , , the primary current phasor is expressed as , , , the secondary current phasor is expressed as , , The amplitude and phase of voltage and current can be obtained from the phasor.

[0066] Step S130: When the connection group of the distribution transformer is Yyn0, Yd11 or YNd11, the equivalent three-phase parameters are calculated according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor.

[0067] Specifically, we can use the transformer equivalent circuit to get ,

[0068] in, , are the voltage and current phasors of the primary side of the distribution transformer, , are the voltage and current phasors of the secondary side of the distribution transformer, R1 and X1 are the resistance and reactance of the primary winding, R 12 , X 12 is the resistance and reactance of the secondary winding converted to the primary side, and k is the transformation ratio of the distribution transformer.

[0069] It is understandable that , ,get and Based on this, according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor, the process of calculating the equivalent three-phase parameters may include:

[0070] Use the following formula to calculate the equivalent three-phase parameters:

[0071]

[0072] in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

[0073] Step S140: Process the disturbance of the equivalent three-phase parameters to obtain the disturbed three-phase parameters.

[0074] The disturbance ∆ can be an artificially added disturbance and can take a very small value.

[0075] Specifically, the process of processing the equivalent three-phase parameter disturbance and obtaining the disturbed three-phase parameter may include:

[0076] S1401, Yes Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. .

[0077] S1402, Yes The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B .

[0078] S1403, Yes The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the voltage C phase imaginary part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

[0079] It is understandable that if the short-circuit reactance X1+X 12 , it is necessary to change the load size of the transformer and measure again , , , ,Therefore, in order to reduce the number of measurements and realize ,real-time monitoring of short-circuit reactance, the equivalent three-phase ,parameters can be disturbed and the obtained disturbance three-phase ,parameters can be regarded as secondary measurement values ​​and ,can participate in the calculation of short-circuit reactance.

[0080] Step S150: construct a resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbance three-phase parameters, and solve the resistance reactance matrix equation to obtain the three-phase short-circuit reactance value of the distribution transformer.

[0081] Specifically, the resistance reactance matrix equation can be constructed using the following formula:

[0082]

[0083] in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the secondary side winding referred to the primary side.

[0084] Furthermore, the resistance reactance matrix equation can be solved to obtain the short-circuit reactance value of phase A of the distribution transformer: , the short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

[0085] Step S160: display the three-phase short-circuit reactance value, and if the three-phase short-circuit reactance value is abnormal, display the winding deformation alarm prompt of the distribution transformer.

[0086] Specifically, the three-phase short-circuit reactance value can be displayed in real time on the LCD display unit 30. If the three-phase short-circuit reactance value is not within the preset normal value range, it can be determined that the three-phase short-circuit reactance value is abnormal, and then the winding deformation alarm prompt of the distribution transformer can be displayed in real time on the LCD display unit 30 to achieve online real-time monitoring of the distribution transformer winding deformation.

[0087] The online monitoring method for the deformation of the winding of the distribution transformer provided in this embodiment is to collect the three-phase current and voltage signals of the primary and secondary sides of the distribution transformer when the distribution transformer is running with load, and perform fast Fourier transform to obtain the current and voltage phasors of the primary and secondary sides, calculate the equivalent three-phase parameters according to the current and voltage phasors of the primary and secondary sides, and perform disturbance processing on the equivalent three-phase parameters to obtain the disturbed three-phase parameters, construct the resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbed three-phase parameters, solve the equation to obtain the three-phase short-circuit reactance value, and display the winding deformation alarm prompt if the three-phase short-circuit reactance value is abnormal. It can be seen that when the distribution transformer is running, it only needs to sample the current and voltage once, and there is no need to adjust the load of the transformer to measure the short-circuit reactance of the transformer, so as to quickly and accurately judge the deformation of the winding, thereby improving the efficiency of transformer winding deformation monitoring.

[0088] Taking into account the need to convert the line current of the three-phase transformer in some connection groups, based on this, in some embodiments of the present application, when the connection group of the distribution transformer is Dyn11, the primary current phasor obtained by fast Fourier transform is the primary line current phasor, based on this, the primary line current phasor can be converted into phase current as a new primary current phasor, and the equivalent three-phase parameters can be calculated based on the primary voltage phasor, the secondary voltage phasor, the primary current phasor and the secondary current phasor.

[0089] Specifically, the line current measured on the primary side of the distribution transformer can be converted into phase current by the following formula:

[0090]

[0091] in, is the phase current phasor of phase A on the primary side of the distribution transformer, is the phase current of phase B on the primary side of the distribution transformer, is the phase C line current phasor on the primary side of the distribution transformer.

[0092] The following describes a system for implementing online monitoring of distribution transformer winding deformation provided in an embodiment of the present application. The system for implementing online monitoring of distribution transformer winding deformation described below and the method for implementing online monitoring of distribution transformer winding deformation described above can refer to each other.

[0093] See also Figure 1 , Figure 1 A schematic diagram of the structure of a system for online monitoring of winding deformation of a distribution transformer disclosed in an embodiment of the present application.

[0094] like Figure 1As shown, the system may include: a signal acquisition unit 10, an arithmetic logic unit 20, an LCD display unit 30, a voltage sampling circuit 01, a current sampling circuit 02, two voltage transformers and two current transformers, the two voltage transformers are respectively connected to the primary side and the secondary side of the three-phase distribution transformer, one current transformer is connected between the high-voltage bus and the distribution transformer, and the other current transformer is connected between the distribution transformer and the low-voltage bus, the two voltage transformers are connected to the voltage sampling circuit 02, the two current transformers are connected to the current sampling circuit 01, the output end of the voltage sampling circuit 01 and the output end of the current sampling circuit 02 are both connected to the input end of the signal acquisition unit 10, and the output end of the signal acquisition unit 10 is connected to the LCD display unit 30 through the arithmetic logic unit 20;

[0095] The signal acquisition unit 10 is used to collect the three-phase voltage signal of the primary side of the distribution transformer, the three-phase voltage signal of the secondary side of the distribution transformer, the three-phase current signal of the primary side of the distribution transformer, and the three-phase current signal of the secondary side of the distribution transformer when the distribution transformer is running with load;

[0096] The arithmetic logic unit 20 is used to perform fast Fourier transform on the three-phase voltage signal of the primary side, the three-phase voltage signal of the secondary side, the three-phase current signal of the primary side, and the three-phase current signal of the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor; when the connection group of the distribution transformer is Yyn0, Yd11, or YNd11, according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor, calculate the equivalent three-phase parameters, perform disturbance processing on the equivalent three-phase parameters, obtain the disturbed three-phase parameters, construct the resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbed three-phase parameters, and solve the resistance reactance matrix equation to obtain the three-phase short-circuit reactance value of the distribution transformer;

[0097] The LCD display unit 30 is used to display the three-phase short-circuit reactance value, and if the three-phase short-circuit reactance value is abnormal, it will display the winding deformation alarm prompt of the distribution transformer.

[0098] Optionally, the arithmetic logic unit includes:

[0099] The equivalent three-phase parameter calculation unit is used to calculate the equivalent three-phase parameters using the following formula:

[0100]

[0101] in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

[0102] Optionally, the arithmetic logic unit further includes:

[0103] The first disturbance superposition unit is used to Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. ;

[0104] The second disturbance superposition unit is used to The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B ;

[0105] The third disturbance superposition unit is used to The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase C ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

[0106] Optionally, the arithmetic logic unit further includes:

[0107] The resistance-reactance matrix equation building unit is used to build the resistance-reactance matrix equation using the following formula:

[0108]

[0109] in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the winding on the secondary side converted to the primary side;

[0110] The short-circuit reactance value solving unit is used to solve the resistance reactance matrix equation to obtain the short-circuit reactance value of phase A of the distribution transformer. The short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

[0111] Optionally, the system further includes:

[0112] A current phasor conversion unit is used to, when the connection group of the distribution transformer is Dyn11, use the primary side current phasor as the primary side line current phasor, convert the primary side line current phasor into a phase current as a new primary side current phasor, and calculate equivalent three-phase parameters based on the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor.

[0113] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0114] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0115] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be 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 present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An online monitoring method for the deformation of a distribution transformer winding, characterized in that: include: When the distribution transformer is running under load, collecting the three-phase voltage signal of the primary side of the distribution transformer, the three-phase voltage signal of the secondary side of the distribution transformer, the three-phase current signal of the primary side of the distribution transformer, and the three-phase current signal of the secondary side of the distribution transformer; Performing fast Fourier transform on the three-phase voltage signal on the primary side, the three-phase voltage signal on the secondary side, the three-phase current signal on the primary side, and the three-phase current signal on the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor; When the connection group of the distribution transformer is Yyn0, Yd11 or YNd11, the equivalent three-phase parameters are calculated according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor; Processing the disturbance of the equivalent three-phase parameters to obtain the disturbed three-phase parameters; Constructing a resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbance three-phase parameters, and solving the resistance reactance matrix equation to obtain a three-phase short-circuit reactance value of the distribution transformer; The three-phase short-circuit reactance value is displayed, and if the three-phase short-circuit reactance value is abnormal, a winding deformation alarm prompt of the distribution transformer is displayed.

2. The method according to claim 1, characterized in that: Calculating equivalent three-phase parameters according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor includes: Use the following formula to calculate the equivalent three-phase parameters: in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

3. The method according to claim 2, characterized in that The equivalent three-phase parameter disturbance is processed to obtain the disturbed three-phase parameters, including: right Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. ; right The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B ; right The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the voltage C phase imaginary part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

4. The method according to claim 3, characterized in that A resistance-reactance matrix equation is constructed based on the equivalent three-phase parameters and the disturbance three-phase parameters, and the resistance-reactance matrix equation is solved to obtain the three-phase short-circuit reactance value of the distribution transformer, including: The resistance reactance matrix equation is constructed using the following formula: in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the winding on the secondary side converted to the primary side; Solving the resistance reactance matrix equation, the short-circuit reactance value of phase A of the distribution transformer is obtained as The short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

5. The method according to any one of claims 1 to 4, characterized in that: Also includes: When the connection group of the distribution transformer is Dyn11, the primary side current phasor is used as the primary side line current phasor, and the primary side line current phasor is converted into a phase current as a new primary side current phasor; Equivalent three-phase parameters are calculated according to the primary-side voltage phasor, the secondary-side voltage phasor, the primary-side current phasor, and the secondary-side current phasor.

6. An online monitoring system for the deformation of a distribution transformer winding, characterized in that: It includes a signal acquisition unit, an arithmetic logic unit, an LCD display unit, a voltage sampling circuit, a current sampling circuit, two voltage transformers and two current transformers, the two voltage transformers are respectively connected to the primary side and the secondary side of the three-phase distribution transformer, one current transformer is connected between the high-voltage bus and the distribution transformer, and the other current transformer is connected between the distribution transformer and the low-voltage bus, the two voltage transformers are connected to the voltage sampling circuit, the two current transformers are connected to the current sampling circuit, the output end of the voltage sampling circuit and the output end of the current sampling circuit are both connected to the input end of the signal acquisition unit, and the output end of the signal acquisition unit is connected to the LCD display unit through the arithmetic logic unit; The signal acquisition unit is used to collect the three-phase voltage signal of the primary side of the distribution transformer, the three-phase voltage signal of the secondary side of the distribution transformer, the three-phase current signal of the primary side of the distribution transformer, and the three-phase current signal of the secondary side of the distribution transformer when the distribution transformer is running under load; The arithmetic logic unit is used to perform fast Fourier transform on the three-phase voltage signal of the primary side, the three-phase voltage signal of the secondary side, the three-phase current signal of the primary side, and the three-phase current signal of the secondary side, respectively, to obtain the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor; when the connection group of the distribution transformer is Yyn0, Yd11, or YNd11, according to the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor, and the secondary side current phasor, calculate the equivalent three-phase parameters, perform disturbance processing on the equivalent three-phase parameters, obtain the disturbed three-phase parameters, construct the resistance reactance matrix equation based on the equivalent three-phase parameters and the disturbed three-phase parameters, and solve the resistance reactance matrix equation to obtain the three-phase short-circuit reactance value of the distribution transformer; The LCD display unit is used to display the three-phase short-circuit reactance value, and if the three-phase short-circuit reactance value is abnormal, it will display the winding deformation alarm prompt of the distribution transformer.

7. The system according to claim 6, characterized in that The arithmetic logic unit comprises: The equivalent three-phase parameter calculation unit is used to calculate the equivalent three-phase parameters using the following formula: in, is the transformation ratio of the distribution transformer, is an imaginary unit, is the voltage phase A of the primary side, is the voltage phase B of the primary side, is the voltage C phase phasor of the primary side, is the voltage phase A of the secondary side, is the voltage B phase phasor of the secondary side, is the voltage C phase phasor of the secondary side, is the current A phase phasor of the primary side, is the current B phase phasor of the primary side, is the current C phase phasor of the primary side, is the current A phase phasor of the secondary side, is the current B phase phasor of the secondary side, is the current C phase phasor of the secondary side, is the real part of the voltage A phase vector, is the imaginary part of the voltage phase A vector, is the real part of the current A phase vector, is the imaginary part of the current A phase vector, is the real part of the voltage B phase vector, is the imaginary part of the voltage B phase vector, is the real part of the current B phase vector, is the imaginary part of the current B phase vector, is the real part of the voltage C phase vector, is the imaginary part of the voltage C phase vector, is the real part of the current C phase vector, is the imaginary part of the current C phase vector.

8. The system according to claim 7, characterized in that The arithmetic logic unit also includes: The first disturbance superposition unit is used to Superimpose the first preset disturbance value to obtain the real part disturbance parameter of voltage phase A ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase A. ,right The first preset disturbance is superimposed to obtain the real part disturbance parameter of current A phase. ,right The first preset disturbance is superimposed to obtain the disturbance parameter of the imaginary part of the current phase A. ; The second disturbance superposition unit is used to The second preset disturbance is added to obtain the real part disturbance parameter of voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the voltage phase B. ,right The second preset disturbance amount is superimposed to obtain the real part disturbance parameter of current B phase ,right The second preset disturbance amount is superimposed to obtain the disturbance parameter of the imaginary part of the current phase B ; The third disturbance superposition unit is used to The third preset disturbance is added to obtain the real part disturbance parameter of phase C voltage. ,right The third preset disturbance amount is superimposed to obtain the voltage C phase imaginary part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase real part disturbance parameter ,right The third preset disturbance amount is superimposed to obtain the current C phase imaginary part disturbance parameter .

9. The system according to claim 8, characterized in that The arithmetic logic unit also includes: The resistance-reactance matrix equation building unit is used to build the resistance-reactance matrix equation using the following formula: in, is the phase A resistance of the primary winding, is the B-phase resistance of the primary winding, is the C-phase resistance of the primary winding, is the A-phase reactance of the primary winding, is the B-phase reactance of the primary winding, is the C-phase reactance of the primary winding, is the A-phase resistance of the secondary winding converted to the primary side, is the B-phase resistance of the secondary winding converted to the primary side, is the C-phase resistance of the secondary winding converted to the primary side, is the A-phase reactance of the secondary winding referred to the primary side, is the B-phase reactance of the secondary winding referred to the primary side, is the C-phase reactance of the winding on the secondary side converted to the primary side; The short-circuit reactance value solving unit is used to solve the resistance reactance matrix equation to obtain the short-circuit reactance value of phase A of the distribution transformer. The short-circuit reactance of phase B of the distribution transformer is , and the short-circuit reactance of phase C of the distribution transformer is .

10. The system according to any one of claims 6 to 9, characterized in that: The system also includes: A current phasor conversion unit is used to, when the connection group of the distribution transformer is Dyn11, use the primary side current phasor as the primary side line current phasor, convert the primary side line current phasor into a phase current as a new primary side current phasor, and calculate equivalent three-phase parameters based on the primary side voltage phasor, the secondary side voltage phasor, the primary side current phasor and the secondary side current phasor.

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