Transformer fault identification system and method, computer device, and computer readable storage medium

Abstract

The present application discloses a transformer fault identification system and method, a computer device, and a computer readable storage medium. The method comprises: acquiring the maximum value Udtmax and the minimum value Udtmin among the three-phase voltage integral value rise rates, and if (Udtmax-Udtmin)≥Udtset, determining that a first discrimination condition is satisfied; acquiring a phase current integral value Iamp and a phase voltage integral value Uamp, if Iamp≥Iset, determining that the system is in a current state, and if Uamp≥Uset, determining that the system is in a voltage state, wherein the moment of the current state is tIamp, and if the system is not in a voltage state at the expiration of the moment tIamp+tset, determining that a second discrimination condition is satisfied; obtaining a sequence subset {Zp1, Zp2, Zp3, LZpN} of measured impedance values at N sampling moments, and the maximum measured impedance value Zmax and the minimum measured impedance value Zmin among the sequence subset; when (I) is satisfied, determining that a third discrimination condition is satisfied; on the basis of a differential motion equation, determining that the differential ratio characteristic is satisfied; and when the first discrimination condition or the second discrimination condition or the third discrimination condition is satisfied, and the differential ratio characteristic is satisfied, starting a differential protection action of a transformer. According to the method, the differential protection action of the transformer can be timely started, so that the transformer is protected.

Description

Transformer fault identification system, method, computer device and computer readable storage medium

[0001] Related applications

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on June 21, 2023, with application number 2023107486043 and application name “Transformer Fault Identification System, Method, Computer Device and Computer-Readable Storage Medium”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the technical field of power system relay protection, and specifically relates to a transformer fault identification system, method, computer device and computer-readable storage medium. Background Art

[0004] During the construction of new power systems, a large number of flexible transmission equipment (FTE) are connected to the system. When these equipment are in operation, they typically require the main transformer to be put into operation via a zero-start voltage step-up method. During this zero-start voltage step-up process, if a transformer fault occurs, the control process of the FTE will also cause calculated harmonics to be generated in the current waveform. These harmonics affect the transformer differential protection, which uses the second harmonic-based blocking criterion for magnetizing inrush current, causing the differential protection to operate slowly or even fail to operate. Therefore, it is necessary to find methods other than harmonic discrimination to distinguish magnetizing inrush current from system faults.

[0005] Summary of the Invention

[0006] Purpose of the invention: The present application provides a transformer fault identification system, method, computer device and computer-readable storage medium to solve the problem of how to avoid affecting the transformer during the zero-start boost process.

[0007] Technical solution: This application provides a transformer fault identification system, including:

[0008] The first judging unit is used to obtain the three-phase voltage integral value rising rate U dta 、U dtb and U dtc The maximum value U in dtmax and minimum value U dtmin , and is used to obtain the preset parameter U of the voltage integral value rise rate difference dtset ; The first discrimination unit is used to (U dtmax -U dtmin )≥U dtset When , it is determined that the first discrimination condition is met;

[0009] The second judging unit is used to obtain the phase current integral value Iamp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set The second discrimination unit is used to amp ≥I set When the system is judged to be in a flow state, it is used to amp ≥U set When the system is in a pressurized state, the system is judged to be in a flow state; let the time when the system appears in a flow state be t Iamp The second discrimination unit is used to cut off t Iamp +t set When the system is not under pressure at that moment, it is determined that the second judgment condition is met;

[0010] The third discrimination unit is used to obtain a sequence subset of the measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN}, to obtain the maximum measured impedance value Z of the sequence subset max , minimum measured impedance value Z min The third discrimination unit is used to When , it is determined that the third discrimination condition is met;

[0011] a proportional differential determination unit, the proportional differential determination unit being used to obtain a differential action equation to determine whether a differential proportional characteristic is satisfied;

[0012] A starting unit is used to start the transformer differential protection action when any of the first discrimination condition, the second discrimination condition, and the third discrimination condition are met and the differential proportion characteristic is satisfied.

[0013] In some embodiments, the differential action equation satisfies:

[0014] Where k b1 、k b2 、k b3 is the proportional constant, I h1 , I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd It is the minimum action setting value of transformer proportional differential;

[0015] When I d When the differential action equation is satisfied, the differential proportional characteristic is satisfied.

[0016] In some embodiments, k b1 、k b2 and k b3 Satisfy respectively: 0≤k b1 ≤1, 0≤k b2 ≤1, 0≤k b2 ≤1; and / or,

[0017] I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or,

[0018] I h1 and I h2 The value is 0.2 to 6 times the rated current of the transformer.

[0019] In some embodiments, K set is a constant value, K set The value range satisfies: 2≤K set ≤20.

[0020] In some embodiments, the first determination unit is used to calculate the phase voltage integral value rising rate U dt , satisfying: U dt =U t2 -U t1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set ; According to the phase voltage integral value rising rate U dt , calculate the three-phase voltage integral value rising rate U respectively dta 、U dtb and U dtc .

[0021] In some embodiments, T set Satisfies: T≤T set ≤5T, where T is the signal cycle duration; and / or,

[0022] U dtset Meets: 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

[0023] In some embodiments, I set Satisfaction: 0.1I n ≤I set ≤I n , I n is the transformer rated current; and / or,

[0024] U set Meet: 01U n ≤U set ≤U n , U n is the transformer rated voltage; and / or,

[0025] t set Satisfies: 0≤t set ≤5T, where T is the signal cycle duration.

[0026] The present application also provides a transformer fault identification method, comprising the following steps:

[0027] Get the three-phase voltage integral value rising rate U dta 、U dtb 、U dtc The maximum value U in dtmax and minimum value U dtmin , obtain the preset parameter U of the voltage integral value rise rate difference dtset ; if (U dtmax -U dtmin )≥U dtset , it is determined that the first discrimination condition is met;

[0028] Get the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set , when I amp ≥I set When U amp ≥U set When the system is judged to be in a pressurized state, the time t at which the system appears to be in a flow state is obtained. Iamp , the preset parameters of duration t set , if the cutoff t Iamp +t set At this moment, the system is not under pressure, and the second judgment condition is determined to be met;

[0029] Obtain a subset of the measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN}, find the maximum measured impedance value Z in the sequence subset max , minimum measured impedance value Z min ;exist When , it is determined that the third discrimination condition is met;

[0030] Obtain the differential action equation and determine whether the differential proportional characteristic is satisfied;

[0031] When any one of the first judgment condition, the second judgment condition, and the third judgment condition is met and the differential proportional characteristic is satisfied, the transformer differential protection action is started.

[0032] In some embodiments, the differential action equation satisfies:

[0033] Where k b1 、k b2 、k b3 is the proportional constant, I h1 , I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd It is the minimum action setting value of transformer proportional differential;

[0034] If I d The differential action equation is satisfied and the differential proportional characteristic is satisfied.

[0035] In some embodiments, k b1 、k b2 and k b3 Satisfy respectively: 0≤k b1 ≤1, 0≤k b2 ≤1, 0≤k b2 ≤1; and / or,

[0036] I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or,

[0037] I h1 and I h2 The value is 0.2 to 6 times the rated current of the transformer.

[0038] In some embodiments, K set is a constant value, K set The value range satisfies: 2≤K set ≤20.

[0039] In some embodiments, the phase voltage integral value rising rate U is calculated dt , satisfying: U dt =U t2 -U t1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set; According to the phase voltage integral value rising rate U dt , calculate the three-phase voltage integral value rising rate U respectively dta 、U dtb and U dtc .

[0040] In some embodiments, T set Satisfies: T≤T set ≤5T, where T is the signal cycle duration; and / or,

[0041] U dtset Meet 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

[0042] In some embodiments, I set Satisfaction: 0.1I n ≤I set ≤I n , I n is the transformer rated current; and / or,

[0043] U set Satisfaction: 0.01U n ≤U set ≤U n , U n is the transformer rated voltage; and / or,

[0044] t set Satisfies: 0≤t set ≤5T, where T is the signal cycle duration.

[0045] In some embodiments, K set is a constant value, K set Satisfies: 2≤K set ≤20.

[0046] In some embodiments, k b1 、k b2 and k b3 Satisfies: 0≤k b1 ≤1, 0≤k b2 ≤1, 0≤k b2 ≤1; and / or,

[0047] I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or,

[0048] I h1 and I h2 The value is 0.2 to 6 times the rated current of the transformer.

[0049] The present application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the transformer fault identification method described above are implemented.

[0050] The present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the transformer fault identification method described above are implemented.

[0051] Beneficial effects: Compared with the prior art, the transformer fault identification system, method, computer device and computer readable storage medium of the present application include: a first discrimination unit, the first discrimination unit is used to obtain the three-phase voltage integral value rising rate U dta 、U dtb and U dtc The maximum value U in dtmax and minimum value U dtmin , and is used to obtain the preset parameter U of the voltage integral value rise rate difference dtset ; The first discrimination unit is used to (U dtmax -U dtmin )≥U dtset When , it is determined that the first discrimination condition is met;

[0052] The second judging unit is used to obtain the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set The second discrimination unit is used to amp ≥I set When the system is judged to be in a flow state, it is used to amp ≥U set When the system is in a pressurized state, the system is judged to be in a flow state; let the time when the system appears in a flow state be t Iamp The second discrimination unit is used to cut off t Iamp +t set When the system is not under pressure at the moment, it is determined that the second discrimination condition is met; a third discrimination unit is used to obtain a sequence subset of the measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN}, to obtain the maximum measured impedance value Z of the sequence subset max , minimum measured impedance value Z min The third discrimination unit is used to When the first discrimination condition is met, it is determined that the third discrimination condition is met; a proportional differential discrimination unit, the proportional differential discrimination unit is used to obtain a differential action equation to determine whether the differential proportional characteristic is satisfied; a starting unit, the starting unit is used to start the transformer differential protection action when any one of the first discrimination condition, the second discrimination condition, and the third discrimination condition is met and the differential proportional characteristic is satisfied.

[0053] Therefore, the transformer fault identification system of the present application can determine whether the first judgment condition is met through the first judgment unit, determine whether the second judgment condition is met through the second judgment unit, determine whether the third judgment condition is met through the third judgment unit, and determine whether the differential proportional characteristic is met through the proportional differential judgment unit; in any case of meeting the first judgment condition, the second judgment condition, and the third judgment condition, and when the differential proportional characteristic is met, the transformer differential protection action can be started through the starting unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0055] FIG1 is a schematic diagram of a flow chart of a transformer fault identification method provided in an embodiment of the present application;

[0056] FIG2 is a schematic diagram of the structure of a transformer fault identification system provided in an embodiment of the present application;

[0057] Reference numerals: 100 - first determination unit, 200 - second determination unit, 300 - third determination unit, 400 - proportional differential determination unit, 500 - starting unit. DETAILED DESCRIPTION

[0058] 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 embodiments described 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 those skilled in the art without making creative efforts are within the scope of protection of this application.

[0059] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly specified and specifically limited. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0060] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0061] Please refer to Figure 1. This application provides a transformer fault identification system for realizing transformer fault identification, which belongs to the field of relay protection technology. This application's transformer fault identification system, in particular, is a transformer fault identification system based on voltage and current measurement value ratio discrimination, including: a first discrimination unit 100, the first discrimination unit 100 is used to obtain the three-phase voltage integral value rising rate U dta 、U dtb and U dtc The maximum value U in dtmax and minimum value U dtmin , and is used to obtain the preset parameter U of the voltage integral value rise rate difference dtset ; The first discrimination unit 100 is used to (U dtmax -U dtmin )≥U dtset When the first judgment condition is met, the second judgment unit 200 is used to obtain the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set The second discrimination unit 200 is used to amp ≥I set When the system is judged to be in a flow state, the second judging unit 200 is used to amp ≥U setWhen the system is in a pressurized state, the system is judged to be in a flow state; let the time when the system appears in a flow state be t Iamp The second discrimination unit 200 is used to cut off t Iamp +t set When the system is not under pressure at the moment, it is determined that the second judgment condition is met; the third judgment unit 300 is used to obtain a sequence of measured impedance values ​​at N sampling moments to form a sequence subset {Z p1 ,Z p2 ,Z p3 ,LZ pN}, to obtain the maximum measured impedance value Z of the sequence subset max , minimum measured impedance value Z min The third judging unit 300 is used to When the third discrimination condition is met, it is determined that the third discrimination condition is met; the proportional differential discrimination unit 400, the proportional differential discrimination unit 400 is used to calculate the differential action equation to determine whether the differential proportional characteristic is met; the starting unit 500, the starting unit 500 is used to start the transformer differential protection action when any of the first discrimination condition, the second discrimination condition, and the third discrimination condition are met and the differential proportional characteristic is met.

[0062] In some embodiments, in the proportional differential determination unit 400, the differential action equation satisfies:

[0063] In formula 1, k b1 、k b2 、k b3 is the proportional constant, I h1 , I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd is the minimum action value of transformer proportional differential; when I d When equation 1 is satisfied, the differential proportional characteristic is satisfied.

[0064] In some embodiments, in the ratio difference determination unit 400, in the above formula 1, k b1 、k b2 、k b3 Satisfies: 0≤k b1 ≤1, 0≤k b2 ≤1, 0≤k b2 ≤1;I cdqd Take 0.05 to 2 times of the transformer rated current; I h1 and I h2 The value is 0.2 to 6 times the rated current of the transformer.

[0065] In some embodiments, the first determination unit 100 is used to calculate the phase voltage integral value rising rate U dt , satisfying: U dt =U t2 -U t1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set Furthermore, in some embodiments, in the first determination unit 100, according to the phase voltage integral value rising rate U dt , calculate the three-phase voltage integral value rising rate U respectively dta , voltage integral value rise rate U dtb , voltage integral value rise rate U dtc .

[0066] In some embodiments, in the second determination unit 200, T set is the preset parameter of time difference, T set The value range of satisfies: T≤T set ≤5T, where T is the signal cycle duration.

[0067] In some embodiments, in the second determination unit 200, U dtset It is the preset parameter of the voltage integral value rising rate difference, and the value range is 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

[0068] In some embodiments, in the second determination unit 200, I set is the preset parameter of current, I set The value range meets: 0.1I n ≤I set ≤I n , I n is the rated current of the transformer.

[0069] In some embodiments, in the second determination unit 200, U set is the setting parameter of the phase voltage integral value threshold, U set The value range meets: 0.01U n ≤U set ≤U n , U n is the rated voltage of the transformer.

[0070] In some embodiments, in the second determination unit 200, t setis the preset parameter of duration, t set The value range of satisfies: 0≤t set ≤5T, where T is the signal cycle duration.

[0071] In some embodiments, in the third determination unit 300, the measured impedance is calculated based on the half-wave integral value of the voltage and current, and the fluctuation of the measured impedance is determined. The measured impedance values ​​at multiple sampling moments of the signal waveform to be analyzed are calculated using a half-wave algorithm to obtain a sequence of measured impedance values ​​at multiple sampling moments. In the third determination unit 300, the sequence of measured impedance values ​​at multiple sampling moments includes a number of measured impedance values ​​greater than or equal to the number of sampling points in one cycle of the signal waveform to be analyzed. The number of sampling points in one cycle of the signal waveform to be analyzed is denoted as N, and N consecutive measured impedance values ​​in the sequence of measured impedance values ​​are taken to form a sequence subset {Z p1 ,Z p2 ,Z p3 ,LZ pN}.

[0072] In some embodiments, in the third determination unit 300, K set is a constant value, K set The value range satisfies: 2≤K set ≤20.

[0073] In the transformer fault identification system of the present application, the first discrimination unit 100 includes a voltage cycle rise rate element discrimination element 101; the second discrimination unit 200 includes a voltage and current excess discrimination element 201; the third discrimination unit 300 includes a measurement impedance discrimination element 301; the proportional differential discrimination unit 400 includes a proportional differential discrimination element 401; and the starting unit 500 includes a starting element 501. In the embodiment of the present application, the proportional differential discrimination element 401 is used to determine whether the differential proportional characteristic is satisfied. If I d When the above formula 1 is satisfied, the proportional differential discrimination element 401 generates an action; the starting element 501 is used to receive an indication signal indicating that the voltage period rise rate element discrimination element 101 meets the action condition, the voltage and current excess discrimination element 201 meets the action condition, and the measured impedance discrimination element 301 meets the action condition. The starting element 501 also receives an indication signal indicating that the proportional differential discrimination element 401 meets the action condition.

[0074] The transformer fault identification system of the present application can determine whether the voltage period rise rate determination element 101 meets the first determination condition through the first determination unit 100, determine whether the voltage and current excess determination element 201 meets the second determination condition through the second determination unit 200, determine whether the measured impedance determination element 301 meets the third determination condition through the third determination unit 300, determine whether the differential proportional characteristic is satisfied through the proportional differential determination unit 400, and can be used to start the transformer differential protection action through the starting unit 500 when any of the first determination condition, the second determination condition, and the third determination condition are met and the differential proportional characteristic is satisfied.

[0075] Based on the above-mentioned transformer fault identification system, especially the above-mentioned transformer fault identification system based on voltage and current measurement value ratio discrimination, the present application also provides a transformer fault identification method, including the following steps:

[0076] Step 100: Obtain the three-phase voltage integral value rising rate U dta 、U dtb 、U dtc The maximum value U in dtmax and minimum value U dtmin , obtain the preset parameter U of the voltage integral value rise rate difference dtset ; if (U dtmax -U dtmin )≥U dtset , it is determined that the first discrimination condition is met;

[0077] In this step 100, the A phase voltage integral value rising rate is obtained as U dta The rising rate of the integral value of the voltage of phase B is U dtb The rising rate of the integral value of the phase C voltage is U dtc , obtain the phase voltage integral value rising rate of the three-phase voltage, that is, U dta 、U dtb 、U dtc The maximum value in is U dtmax , obtain the phase voltage integral value rise rate U of the three-phase voltage dta 、U dtb 、U dtc The minimum value in is U dtmin , to determine that the voltage period rise rate discrimination element 101 meets the first discrimination condition;

[0078] In this step 100, the following steps are also included:

[0079] Step 110: Calculate the phase voltage integral value rising rate U dt , satisfying: U dt =U t2 -Ut1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set .

[0080] In this step 110, T set is the setting parameter of time difference, T set The value range of satisfies: T≤T set ≤5T, where T is the signal cycle duration.

[0081] In this step 110, U dt is T milliseconds apart t2 The voltage integral value U at the moment t2 and the voltage integral value U at time t1 t1 The difference between the phase voltage integral value and the rising rate U dt The above calculation formula is used to calculate the rising rate of the integral value of the phase A voltage: U dta Calculate the rising rate of the integral value of the B phase voltage as U dtb Calculate the C phase voltage integral value rising rate as U dtc , and then select the phase voltage integral value rising rate of the three-phase voltage, that is, U dta 、U dtb 、U dtc The maximum value in is U dtmax , and then select the phase voltage integral value rise rate U of the three-phase voltage dta 、U dtb 、U dtc The minimum value in is denoted as U dtmin , so according to (U dtmax -U dtmin )≥U dtset , it can be determined that the voltage period rise rate determination element 101 meets the first determination condition.

[0082] In this step 110, U dtset Meets: 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

[0083] Step 200: Obtain phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set , when I amp ≥I set When Uamp ≥U set When the system is judged to be in a pressurized state, the time t at which the system appears to be in a flow state is obtained. Iamp , the preset parameters of duration t set , if the cutoff t Iamp +t set At this moment, the system is not under pressure, and the second judgment condition is determined to be met;

[0084] In this step 200, I set is the preset parameter of current, I set The value range meets: 0.1I n ≤I set ≤I n , I n is the rated current of the transformer;

[0085] In this step 200, U set is the preset parameter of the phase voltage integral value, U set The value range meets: 0.01U n ≤U set ≤U n , U n is the rated voltage of the transformer;

[0086] In this step 200, t set is the preset parameter of duration, t set The value range of satisfies: 0≤t set ≤5T, T is the signal cycle length;

[0087] Therefore, in this step 200, by obtaining the phase current integral value I amp , when I amp ≥I set When the system is judged to be in a current state, the phase voltage integral value U is obtained. amp , when U amp ≥U set When the system is judged to be in a pressurized state; then according to the voltage integral value U amp , current integral value I amp The timing of satisfying the excess set value is used to determine whether the second judgment condition is met.

[0088] Step 300: Obtain a subset of the measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN}, find the maximum measured impedance value Z in the sequence subset max , minimum measured impedance value Z min ;exist When , it is determined that the third judgment condition is met.

[0089] In this step 300, the measured impedance values ​​at multiple sampling moments of the signal waveform to be analyzed are calculated to obtain a sequence of measured impedance values ​​at multiple sampling moments; by obtaining the number of sampling points N of one cycle of the signal waveform to be analyzed, N consecutive measured impedance values ​​in the sequence of measured impedance values ​​are taken to form a sequence subset {Z p1 ,Z p2 ,Z p3 ,LZ pN}; Obtain the maximum measured impedance value Z in the sequence subset max , minimum measured impedance value Z min ;when , it is determined that the third discrimination condition is met.

[0090] In this step 300, in some embodiments, the number of measured impedance values ​​included in the sequence of measured impedance values ​​at multiple sampling moments is not less than the number of sampling points in one cycle of the waveform of the signal to be analyzed.

[0091] In this step 300, in some embodiments, K set is a constant value, K set The value range satisfies: 2≤K set ≤20.

[0092] In this step 300, in some embodiments, the measured impedance value is obtained by using a half-wave Fourier algorithm. In other embodiments, the measured impedance value may also be obtained by using a half-wave integration algorithm.

[0093] Therefore, in step 300, the fluctuation of the measured impedance can be determined by calculating the measured impedance based on the half-wave integral values ​​of the voltage and current.

[0094] Step 400: Calculate the differential action equation to satisfy:

[0095] In formula 1, k b1 、k b2 、k b3 is the proportional constant, I h1 , I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd It is the minimum action setting value of transformer proportional differential;

[0096] In some embodiments, according to the phase currents I1 to I m Calculate the differential action equation above.

[0097] In step 400, the proportional differential determination element 401 is used to determine whether the differential proportional characteristic is satisfied; in this step 400, if I d When equation 1 is satisfied, the differential proportional characteristic is satisfied, and the proportional differential determination element 401 is activated.

[0098] Step 500: When any one of the first judgment condition, the second judgment condition, and the third judgment condition is met and the differential proportional characteristic is satisfied, the transformer differential protection action is started.

[0099] In step 500, when the starting element 501 receives an indication signal that the voltage cycle rise rate element judgment element 101 meets the action conditions, the voltage and current excess judgment element 201 meets the action conditions, and the measured impedance judgment element 301 meets the action conditions, and the starting element 501 receives an indication signal that the proportional differential judgment element 401 meets the action conditions, the transformer differential protection action is started.

[0100] The method of the transformer fault identification system mentioned in the present application comprises the following steps: obtaining the three-phase voltage integral value rising rate U dta 、U dtb 、U dtc The maximum value U in dtmax and minimum value U dtmin , obtain the preset parameter U of the voltage integral value rise rate difference dtset ; if (U dtmax -U dtmin )≥U dtset , determine that the first judgment condition is met; obtain the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set , when I amp ≥I set When U amp ≥U set When the system is judged to be in a pressurized state, the time t at which the system appears to be in a flow state is obtained. Iamp , the preset parameters of duration t set , if the cutoff t Iamp +t set At this moment, the system is not in a pressurized state, and it is determined that the second discrimination condition is met; a sequence subset of the measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN}, find the maximum measured impedance value Z in the sequence subset max , minimum measured impedance value Z min ;exist When the voltage is 0.000V, the third judgment condition is determined to be met; the differential action equation is obtained to determine whether the differential proportional characteristic is satisfied; if any of the first judgment condition, the second judgment condition, or the third judgment condition is met, and the differential proportional characteristic is satisfied, the transformer differential protection action is initiated. This achieves the purpose of identifying and detecting the zero-start boost state of the transformer.

[0101] The present application also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method when executing the computer program.

[0102] The present application also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when the computer program is executed by a processor.

[0103] The transformer fault identification system, method, computer device and computer readable storage medium of the present application include: a first determination unit 100, the first determination unit 100 is used to obtain the three-phase voltage integral value rising rate U dta 、U dtb and U dtc The maximum value U in dtmax and minimum value U dtmin , and is used to obtain the preset parameter U of the voltage integral value rise rate difference dtset ; The first discrimination unit 100 is used to (U dtmax -U dtmin )≥U dtset When the first judgment condition is met, the second judgment unit 200 is used to obtain the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set The second discrimination unit 200 is used to amp ≥I set When the system is judged to be in a flow state, the second judging unit 200 is used to amp ≥U set When the system is in a pressurized state, the system is judged to be in a flow state; let the time when the system appears in a flow state be t Iamp The second discrimination unit 200 is used to cut off t Iamp +t set When the system is not under pressure at the moment, it is determined that the second judgment condition is met; the third judgment unit 300 is used to obtain a sequence of measured impedance values ​​at N sampling moments to form a sequence subset {Z p1 ,Z p2 ,Z p3 ,LZpN}, to obtain the maximum measured impedance value Z of the sequence subset max , minimum measured impedance value Z min The third judging unit 300 is used to When the third discrimination condition is met, the proportional differential discrimination unit 400 is used to calculate the differential action equation to determine whether the differential proportional characteristic is met; the starting unit 500 is used to start the transformer differential protection action when any of the first discrimination condition, the second discrimination condition, and the third discrimination condition are met, and the differential proportional characteristic is met. Therefore, the transformer fault identification system of the present application can determine whether the voltage rise rate discrimination element 101 meets the first discrimination condition through the first discrimination unit 100, determine whether the voltage and current excess discrimination element 201 meets the second discrimination condition through the second discrimination unit 200, determine whether the measured impedance discrimination element 301 meets the third discrimination condition through the third discrimination unit 300, and determine whether the differential proportional characteristic is met through the proportional differential discrimination unit 400; when any of the first discrimination condition, the second discrimination condition, and the third discrimination condition are met, and the differential proportional characteristic is met, the starting unit 500 is used to start the transformer differential protection action.

[0104] The above is a detailed introduction to the transformer fault identification system, method, computer device and computer-readable storage medium provided in the embodiments of the present application. Specific examples are used in this application to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A transformer fault identification system, comprising: A first determination unit (100), the first determination unit (100) is used to obtain a three-phase voltage integral value increase rate U dta , U dtb and U dtc The maximum value U in dtmax and the minimum value U dtmin , and is used to obtain the preset parameter U of the voltage integral value rise rate difference dtset The first discrimination unit (100) is used to dtmax -U dtmin )≥U dtset When , it is determined that the first discrimination condition is met; A second determination unit (200), the second determination unit (200) is used to obtain a phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set The second discrimination unit (200) is used to amp ≥I set When the system is judged to be in a flow state, it is used to amp ≥U set When the system is judged to be in a pressurized state, the time when the system appears in a flow state is t Iamp The second discrimination unit (200) is used to Iamp +t set When the system is not under pressure at that moment, it is determined that the second judgment condition is met; A third determination unit (300), the third determination unit (300) is used to obtain a sequence subset {Z p1 ,Z p2 ,Z p3 ,LZ pN }, to obtain the maximum measured impedance value Z of the sequence subset max , minimum measured impedance value Z min The third discrimination unit (300) is used to When , it is determined that the third discrimination condition is met; A proportional differential determination unit (400), the proportional differential determination unit (400) being used to obtain a differential action equation to determine whether a differential proportional characteristic is satisfied; A starting unit (500) is used to start a transformer differential protection action when any one of a first judgment condition, a second judgment condition, and a third judgment condition is met and a differential ratio characteristic is satisfied.

2. The transformer fault identification system according to claim 1, wherein: The differential action equation satisfies: In the formula, k b1 , k b2 , k b3 is the proportionality constant, I h1 ,I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd It is the minimum action setting value of transformer proportional differential; When I d When the differential action equation is satisfied, the differential proportional characteristic is satisfied.

3. The transformer fault identification system according to claim 2, wherein: k b1 , k b2 and k b3 Satisfy respectively: 0≤k b1 ≤1,0≤k b2 ≤1,0≤k b2 ≤1; and / or, I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or, I h1 and I h2 The value is 0.2 to 6 times of the rated current of the transformer.

4. The transformer fault identification system according to claim 1, wherein: K set is a fixed value, K set The value range of satisfies: 2≤K set ≤20.

5. The transformer fault identification system according to claim 1, wherein: The first determination unit (100) is used to calculate the phase voltage integral value rising rate U dt , satisfying: U dt =U t2 -U t1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set ; According to the phase voltage integral value rising rate U dt , respectively calculate the three-phase voltage integral value rising rate U dta , U dtb and U dtc .

6. The transformer fault identification system according to claim 5, wherein: T set Satisfies: T≤T set ≤5T, T is the signal cycle duration; and / or, U dtset Meets: 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

7. The transformer fault identification system according to claim 1, wherein: I set Satisfaction: 0.1I n ≤I set ≤I n , I n is the transformer rated current; and / or, U set Meets: 01U n ≤U set ≤U n , U n is the transformer rated voltage; and / or, t set Satisfies: 0≤t set ≤5T, T is the signal cycle length.

8. A transformer fault identification method, comprising the following steps: Get the three-phase voltage integral value rising rate U dta , U dtb , U dtc The maximum value U in dtmax and the minimum value U dtmin , obtain the preset parameter U of the voltage integral value rise rate difference dtset ; if (U dtmax -U dtmin )≥U dtset , it is determined that the first discrimination condition is met; Get the phase current integral value I amp , the preset current parameter I set , phase voltage integral value U amp , the preset parameter U of the phase voltage integral value set , when I amp ≥I set When U amp ≥U set When the system is judged to be in a pressurized state, the time t at which the system appears to be in a flow state is obtained. Iamp , the preset parameters of duration t set , if the cutoff t Iamp +t set At this moment, the system is not under pressure, and it is determined that the second judgment condition is met; Obtain a sequence subset of measured impedance values ​​at N sampling moments {Z p1 ,Z p2 ,Z p3 ,LZ pN }, find the maximum measured impedance value Z in the sequence subset max , minimum measured impedance value Z min ;exist When , it is determined that the third discrimination condition is met; Obtain the differential action equation and determine whether the differential proportional characteristic is satisfied; When any of the first judgment condition, the second judgment condition, and the third judgment condition is met and the differential proportional characteristic is satisfied, the transformer differential protection action is started.

9. The transformer fault identification method according to claim 8, wherein: The differential action equation satisfies: In the formula, k b1 , k b2 , k b3 is the proportionality constant, I h1 ,I h2 is the inflection point constant; I1~I m are the phase currents on each side of the transformer, m is a natural number, I d is the differential current, I r is the braking current, I cdqd Transformer ratio Differential minimum action setting; If I d The differential action equation is satisfied and the differential proportional characteristic is satisfied.

10. The transformer fault identification method according to claim 9, wherein: k b1 , k b2 and k b3 Satisfy respectively: 0≤k b1 ≤1,0≤k b2 ≤1,0≤k b2 ≤1; and / or, I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or, I h1 and I h2 The value is 0.2 to 6 times of the rated current of the transformer.

11. The transformer fault identification method according to claim 8, wherein: K set is a fixed value, K set The value range of satisfies: 2≤K set ≤20.

12. The transformer fault identification method according to claim 8, wherein: Calculate the phase voltage integral value rising rate U dt , satisfying: U dt =U t2 -U t1 , where U t2 for t2 The voltage integral value at the moment, U t1 is the voltage integral value at time t1, t2 The time difference is recorded as T set ; According to the phase voltage integral value rising rate U dt , respectively calculate the three-phase voltage integral value rising rate U dta , U dtb and U dtc .

13. The transformer fault identification method according to claim 8, wherein: T set Satisfies: T≤T set ≤5T, T is the signal cycle duration; and / or, U dtset Meet 0.1U n ≤U dtset ≤U n , where U n is the rated voltage.

14. The transformer fault identification method according to claim 8, wherein: I set Satisfaction: 0.1I n ≤I set ≤I n , I n is the transformer rated current; and / or, U set Satisfy: 0.01U n ≤U set ≤U n , U n is the transformer rated voltage; and / or, t set Satisfies: 0≤t set ≤5T, T is the signal cycle length.

15. The transformer fault identification method according to claim 8, wherein: K set is a fixed value, K set Satisfies: 2≤K set ≤20.

16. The transformer fault identification method according to claim 8, wherein: k b1 , k b2 and k b3 Satisfies: 0≤k b1 ≤1,0≤k b2 ≤1,0≤k b2 ≤1; and / or, I cdqd Take 0.05 to 2 times the rated current of the transformer; and / or, I h1 and I h2 The value is 0.2 to 6 times of the rated current of the transformer.

17. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the transformer fault identification method described in any one of claims 8 to 16 are implemented.

18. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the transformer fault identification method described in any one of claims 8 to 16 are implemented.

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