Reactor inter-turn fault protection method and system for tracking voltage and current change trends

Abstract

The present invention discloses a method and system for protecting a reactor from inter-turn faults by tracking voltage and current variation trends, and relates to the technical field of relay protection for power systems. The method and system comprise: collecting voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency; calculating the positive-sequence voltage RMS, three-phase current RMS, positive-sequence current RMS, and negative-sequence current RMS based on the voltage sampling point data and the current sampling point data; determining whether inter-turn protection startup conditions, inter-turn protection action conditions, and inter-turn protection current variation trend conditions are met; and controlling the reactor protection device to operate if the inter-turn protection startup conditions, inter-turn protection action conditions, and inter-turn protection current variation trend conditions are all met within a preset sampling time. The present invention alleviates the technical problem in the prior art of slow relay protection device operation during 35kV reactor inter-turn faults, which may result in damage to the reactor.

Description

Technical Field

[0001] The present invention relates to the technical field of power system relay protection, and in particular to a reactor inter-turn fault protection method and system for tracking voltage and current variation trends. Background Art

[0002] 35kV reactors are critical components in 35kV power systems, primarily used to regulate current, limit short-circuit faults, suppress harmonics, and improve power system stability. These devices are widely used in power systems. Long-term operation or overload can cause aging or degradation of the reactor's winding insulation materials (such as epoxy resin and paper insulation), potentially leading to interturn protection failures. During an interturn fault in a reactor, the fault current gradually increases, raising the conductor temperature and igniting the insulation material, ultimately causing the reactor to catch fire and burn.

[0003] At present, the inter-turn fault protection of reactors is mostly realized by the zero-sequence impedance principle. However, the 35kV power system adopts an ungrounded system, so the inter-turn protection of reactors based on the zero-sequence impedance principle is not applicable to 35kV reactors. In addition, 35kV reactors usually use overcurrent protection to achieve inter-turn fault tripping. However, when the overcurrent protection is delayed, the delay is set at hundreds of milliseconds. During this period, a minor inter-turn fault of the reactor may develop into a serious fault. The overcurrent protection fails to isolate the fault in time and protect the primary equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for protecting a reactor from inter-turn faults by tracking the changing trends of voltage and current in order to solve at least one of the above technical problems.

[0005] In a first aspect, an embodiment of the present invention provides a method for protecting a reactor from inter-turn faults by tracking voltage and current variation trends, which is applied to a reactor protection device in a 35kV power system. The method comprises: collecting voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency; calculating a positive-sequence voltage effective value, a three-phase current effective value, a positive-sequence current effective value, and a negative-sequence current effective value based on the voltage sampling point data and the current sampling point data; judging whether an inter-turn protection start-up condition is satisfied based on a ratio of the positive-sequence voltage effective value, the three-phase current effective value, and the negative-sequence current effective value to the positive-sequence current effective value; judging whether an inter-turn protection action condition is satisfied based on a variation trend of the positive-sequence voltage effective value; judging whether an inter-turn protection current variation trend condition is satisfied based on a ratio of the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value, and the negative-sequence current effective value to the positive-sequence current effective value; and controlling the reactor protection device to operate if the inter-turn protection start-up condition, the inter-turn protection action condition, and the inter-turn protection current variation trend condition are all satisfied within a preset sampling time.

[0006] Furthermore, based on the voltage sampling point data and the current sampling point data, the positive-sequence voltage effective value, the three-phase current effective value, the positive-sequence current effective value and the negative-sequence current effective value are calculated, including: converting the voltage sampling point data and the current sampling point data into voltage vector data and current vector data respectively through a full-cycle Fourier algorithm; and calculating the positive-sequence voltage effective value, the three-phase current effective value, the positive-sequence current effective value and the negative-sequence current effective value based on the voltage vector data and the current vector data.

[0007] Furthermore, the inter-turn protection starting conditions include positive-sequence voltage conditions, three-phase current conditions and ratio conditions; wherein, the positive-sequence voltage conditions include: the effective value of the positive-sequence voltage is greater than a first preset voltage threshold; the three-phase current conditions include: the effective values ​​of the three-phase currents are all greater than a preset no-current threshold; the ratio conditions include: the ratio of the negative-sequence current effective value to the positive-sequence current effective value is greater than a preset sensitivity coefficient.

[0008] Further, based on the positive-sequence voltage effective value, the three-phase current effective value and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, it is judged whether the inter-turn protection starting condition is met, including: based on the positive-sequence voltage effective value, the three-phase current effective value and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, it is judged whether the positive-sequence voltage condition, the three-phase current condition and the ratio condition are all met; if so, it is determined that the inter-turn protection starting condition is met.

[0009] Furthermore, based on the changing trend of the effective value of the positive-sequence voltage, it is judged whether the inter-turn protection action condition is met, including: judging whether the absolute value of the difference between the effective value of the positive-sequence voltage corresponding to the current cycle and the effective value of the positive-sequence voltage corresponding to the historical cycle is less than a second preset voltage threshold; if so, it is determined that the inter-turn protection action condition is met.

[0010] Furthermore, the inter-turn protection current change trend condition includes a phase current change trend condition, a negative-sequence current change trend condition, a positive-sequence current change trend condition and a ratio change trend condition; wherein, the phase current change trend condition includes: the change trend of at least one phase current effective value among the three-phase current effective values ​​is an increasing trend; the negative-sequence current change trend condition includes: the change trend of the negative-sequence current effective value is an increasing trend; the positive-sequence current change trend condition includes: the change trend of the positive-sequence current effective value is an increasing trend; the ratio change trend condition includes: the change trend of the ratio of the negative-sequence current effective value to the positive-sequence current effective value is an increasing trend.

[0011] Further, based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, it is judged whether the inter-turn protection current change trend condition is met, including: based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, it is judged whether the phase current change trend condition, the negative-sequence current change trend condition, the positive-sequence current change trend condition and the ratio change trend condition are all met; if so, it is determined that the inter-turn protection current change trend condition is met.

[0012] In the second aspect, an embodiment of the present invention further provides a reactor inter-turn fault protection system for tracking voltage and current variation trends, which is applied to a reactor protection device of a 35kV power system; comprising: a sampling module, a calculation module, a first judgment module, a second judgment module, a third judgment module and a protection module; wherein the sampling module is used to collect voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency; the calculation module is used to calculate the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value and the negative sequence current effective value based on the voltage sampling point data and the current sampling point data; the first judgment module is used to calculate the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value and the negative sequence current effective value based on the positive sequence voltage effective value, the three-phase current effective value The effective value and the ratio of the negative sequence current effective value to the positive sequence current effective value are used to judge whether the inter-turn protection starting condition is met; the second judgment module is used to judge whether the inter-turn protection action condition is met based on the change trend of the positive sequence voltage effective value; the third judgment module is used to judge whether the inter-turn protection current change trend condition is met based on the three-phase current effective value, the negative sequence current effective value, the positive sequence current effective value and the ratio of the negative sequence current effective value to the positive sequence current effective value; the protection module is used to control the inductor protection device to act if the inter-turn protection starting condition, the inter-turn protection action condition and the inter-turn protection current change trend condition are all met within a preset sampling time.

[0013] In a third aspect, an embodiment of the present invention further provides an electronic device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the method provided in the embodiment of the present invention when executing the computer program.

[0014] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method provided in the embodiment of the present invention is implemented.

[0015] The present invention provides a method and system for protecting a reactor turn-to-turn fault by tracking voltage and current variation trends. This method can reduce the operating delay of a 35kV reactor turn-to-turn fault from hundreds of milliseconds to tens of milliseconds, effectively reducing the duration of the reactor turn-to-turn fault, avoiding the risk of reactor fire and burning, and extending the service life of the reactor equipment. The judgment process uses a sensitive starting coefficient based on the ratio of negative-sequence current to positive-sequence current, effectively determining minor turn-to-turn protection faults. Simultaneously, by tracking the variation trends of positive-sequence voltage and current, the method can effectively and quickly identify a 35kV reactor turn-to-turn fault, improving the sensitivity of the reactor protection. The present invention alleviates the technical problem in the prior art of slow relay protection device operation during a 35kV reactor turn-to-turn fault, potentially damaging the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A flowchart of a method for protecting a reactor from inter-turn faults by tracking voltage and current variation trends provided by an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of a reactor inter-turn fault protection system for tracking voltage and current variation trends provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] Example 1

[0021] Figure 1 This is a flow chart of a method for protecting a reactor from inter-turn faults by tracking the voltage and current variation trends provided by an embodiment of the present invention. The method is applied to a reactor protection device in a 35kV power system. Figure 1 As shown, the method specifically includes the following steps:

[0022] Step S102 : collecting voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency.

[0023] Step S104 , calculating the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value, and the negative sequence current effective value based on the voltage sampling point data and the current sampling point data.

[0024] Step S106 , judging whether the inter-turn protection starting condition is met based on the positive sequence voltage effective value, the three-phase current effective value, and the ratio of the negative sequence current effective value to the positive sequence current effective value.

[0025] Step S108: judging whether the inter-turn protection action condition is met based on the change trend of the positive sequence voltage effective value.

[0026] Step S110 , judging whether the inter-turn protection current variation trend condition is met based on the three-phase current effective value, the negative sequence current effective value, the positive sequence current effective value, and the ratio of the negative sequence current effective value to the positive sequence current effective value.

[0027] Step S112: If the inter-turn protection start-up condition, the inter-turn protection action condition, and the inter-turn protection current change trend condition are all satisfied within the preset sampling time, the reactor protection device is controlled to operate.

[0028] Specifically, step S104 further includes the following steps:

[0029] Step S1041 , converting the voltage sampling point data and the current sampling point data into voltage vector data and current vector data respectively through a full-cycle Fourier algorithm;

[0030] Step S1042 , based on the voltage vector data and the current vector data, calculate the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value, and the negative sequence current effective value.

[0031] Specifically, the full-cycle vector value is expressed as:

[0032]

[0033] in, Represents the full-cycle vector value, is the real part of the vector value, i represents the imaginary unit, and its calculation formula is as follows:

[0034]

[0035] Im is the imaginary part of the vector value, and its calculation formula is as follows:

[0036]

[0037] The formula for calculating the effective value of the vector value is as follows:

[0038]

[0039] In the above formulas (2) and (3): is the sampling point array, j represents the sampling point array number, N represents the number of sampling points in one cycle, and the following definition of N is the same as this.

[0040] Optionally, N=24, that is, the number of points for comparison of one cycle sampling point is 24.

[0041] Through formula (1)~(3) and voltage sampling point data , current sampling point data , calculate the voltage vector data respectively and current vector data .in, Phase distinction includes phase a, phase b, or phase c.

[0042] Then, the positive sequence voltage vector value is calculated by formula (4), formula (5) and formula (6): , positive sequence current vector value and negative sequence current vector value :

[0043]

[0044]

[0045]

[0046] Through the above vector value calculation, the positive sequence voltage vector value used in the present invention is obtained , positive sequence current vector value , negative sequence current vector value and three-phase current vector values .

[0047] The effective values ​​corresponding to the voltage and current vector values ​​are calculated using formula (4):

[0048] Calculate the positive sequence voltage effective value and record it in the positive sequence voltage array corresponding to the current sampling point n , the positive sequence current effective value is recorded in the positive sequence current array corresponding to the current sampling point n , the negative sequence current effective value is recorded in the negative sequence current array corresponding to the current sampling point n , three-phase current effective value And record the positive sequence current array corresponding to the current sampling point n , the ratio of the negative sequence current effective value to the positive sequence current effective value , and record it in the corresponding array .

[0049] Specifically, the inter-turn protection starting conditions include positive sequence voltage conditions, three-phase current conditions and ratio conditions; among them,

[0050] (1) The positive sequence voltage condition includes: the positive sequence voltage effective value is greater than the first preset voltage threshold. For example, if the first preset voltage threshold is 0.95 times the rated voltage, the discriminant of the positive sequence voltage condition is as follows:

[0051] Current positive sequence voltage effective value Greater than 0.95 times rated voltage .

[0052] (2) The three-phase current condition includes: the effective values ​​of the three-phase currents are all greater than the preset no-current threshold. Specifically, the discriminant is as follows:

[0053] The current three-phase effective values ​​are all greater than the preset no-current threshold (For example, the preset no-current threshold is 0.04 times the rated current): .

[0054] (3) The ratio condition includes: the ratio of the negative sequence current effective value to the positive sequence current effective value is greater than the preset sensitivity coefficient. Specifically, the discriminant is as follows:

[0055] Negative sequence current effective value and the positive sequence current effective value Ratio Greater than the preset sensitivity coefficient (For example, Take a number between 0.05 and 0.1): .

[0056] Sensitivity coefficient The value is directly related to the severity of the inter-turn fault. The inter-turn fault of the reactor develops from a minor inter-turn fault to a serious inter-turn fault. The smaller the value, the earlier the turn-to-turn fault can be detected in the process of developing from mild to severe. In the embodiment of the present invention, in order to ensure the sensitivity of turn-to-turn fault identification, The value is set to 0.05, so that it can be started in time when a minor inter-turn fault develops into a moderate fault, ensuring the sensitivity of the inter-turn protection.

[0057] That is, the ratio condition is .

[0058] Specifically, step S106 includes:

[0059] Based on the positive sequence voltage RMS value, the three-phase current RMS value and the ratio of the negative sequence current RMS value to the positive sequence current RMS value, it is determined whether the positive sequence voltage condition, the three-phase current condition and the ratio condition are all satisfied;

[0060] If yes, it is determined that the inter-turn protection starting condition is met.

[0061] Specifically, the discriminant of the inter-turn protection starting condition is as follows:

[0062]

[0063] If the discriminant is satisfied, the inter-turn protection start-up condition is met, otherwise the inter-turn protection action delay is set to 0.

[0064] Specifically, step S108 includes the following steps:

[0065] Determine whether the absolute value of the difference between the positive sequence voltage effective value corresponding to the current cycle and the positive sequence voltage effective value corresponding to the historical cycle is less than a second preset voltage threshold; optionally, the historical cycle is the cycle m cycles before the current cycle;

[0066] If yes, it is determined that the inter-turn protection action conditions are met.

[0067] Optionally, the second preset voltage threshold is 0.02 times the rated voltage value Un.

[0068] Specifically, the process from a turn-to-turn fault in a 35kV reactor to the reactor burning out takes a period of time, at least several hundred milliseconds. During this period, the reactor voltage remains essentially unchanged, maintaining the system voltage level until the reactor burns out, only then dropping to 0V. Based on the voltage characteristics of the turn-to-turn fault, the positive-sequence voltage of the reactor is tracked and judged. The judgment conditions are as follows:

[0069] Current positive sequence voltage effective value The positive sequence voltage RMS value m cycles ago The absolute value of the difference is less than :

[0070]

[0071] For example, the current sampling point count n of the reactor protection device is 36, and m cycles take 1 cycle. The corresponding sampling point count 1 cycle ago is , that is, the current positive sequence voltage effective value judgment formula is as follows:

[0072]

[0073] If the positive-sequence voltage RMS value corresponding to a sampling point count of 36 satisfies the above formula, the positive-sequence voltage is considered unchanged, and the positive-sequence voltage change trend for an interturn fault with a sampling point count of 36 satisfies the interturn protection action conditions. Otherwise, the positive-sequence voltage action conditions for an interturn fault are considered unsatisfied, and the interturn fault protection action delay is set to 0.

[0074] Specifically, the inter-turn protection current change trend condition includes a phase current change trend condition, a negative sequence current change trend condition, a positive sequence current change trend condition and a ratio change trend condition; wherein,

[0075] (1) The phase current change trend condition includes: the change trend of at least one phase current effective value among the three-phase current effective values ​​is an increasing trend.

[0076] The process from a turn-to-turn fault in a 35kV reactor to its burnout takes several hundred milliseconds, at least. During this time, the reactor phase current slowly increases. Based on the current characteristics of the turn-to-turn fault, the reactor phase current is tracked and determined.

[0077] Current phase current effective value The effective value of the phase current corresponding to the m-cycle wave The difference is greater than The effective value of the corresponding phase current before the m-cycle :

[0078]

[0079] For example, the current sampling point count n of the reactor protection device is 36, and m cycles take 1 cycle. The corresponding sampling point count 1 cycle ago is , in order to meet the sufficient sensitivity of inter-turn fault, The value is 0.05, that is, the judgment formula of the phase current change trend condition is as follows:

[0080]

[0081] Taking the occurrence of an ab phase-to-turn fault as an example, when the effective value of the phase a current or the effective value of the phase b current with a sampling point count of 36 satisfies the above formula, it is considered that the phase current change trend with a sampling point count of 36 meets the phase current change trend condition.

[0082] (2) The changing trend conditions of negative sequence current include: the changing trend of the effective value of negative sequence current is an increasing trend.

[0083] Specifically, the process from a turn-to-turn fault in a 35kV reactor to its burnout takes several hundred milliseconds, at least. During this time, the reactor's negative-sequence current slowly increases. Based on the characteristics of negative-sequence current during turn-to-turn faults, the reactor's negative-sequence current is tracked and assessed.

[0084] The judgment conditions are as follows:

[0085] Current negative sequence current effective value The effective value of negative sequence current corresponding to the m-cycle wave front The difference is greater than m times the effective value of negative sequence current before the wave :

[0086]

[0087] For example, the current sampling point count n of the reactor protection device is 36, and m cycles take 1 cycle. The corresponding sampling point count 1 cycle ago is , in order to meet the sufficient sensitivity of inter-turn fault, The value is 0.02, that is, the judgment formula of the negative sequence current change trend condition is as follows:

[0088]

[0089] Taking the occurrence of an ab phase-to-turn fault as an example, when the effective value of the negative-sequence current with a sampling point count of 36 satisfies the above formula, it is considered that the negative-sequence current change trend with a sampling point count of 36 meets the negative-sequence current change trend condition.

[0090] (3) The changing trend conditions of the positive sequence current include: the changing trend of the effective value of the positive sequence current is an increasing trend.

[0091] Specifically, the time between a turn-to-turn fault and the reactor burning out in a 35kV reactor is several hundred milliseconds. During this time, the reactor's positive-sequence current slowly increases. Based on the characteristics of the positive-sequence current during turn-to-turn faults, the reactor's positive-sequence current is tracked and assessed.

[0092] The judgment conditions are as follows:

[0093] Current positive sequence current effective value The positive sequence current effective value corresponding to the m-cycle wave front The difference is greater than The positive sequence current effective value corresponding to the m-cycle wave ;

[0094]

[0095] For example, the current sampling point count n of the reactor protection device is 36, and m cycles take 1 cycle. The corresponding sampling point count 1 cycle ago is , in order to meet the sufficient sensitivity of inter-turn fault, The value is 0.05, that is, the judgment formula of the positive sequence current change trend condition is as follows:

[0096]

[0097] Taking the occurrence of an ab phase-to-turn fault as an example, when the positive sequence current effective value with a sampling point count of 36 satisfies the above formula, it is considered that the positive sequence current change trend with a sampling point count of 36 meets the positive sequence current change trend condition.

[0098] (4) The ratio change trend conditions include: the change trend of the ratio of the negative sequence current effective value to the positive sequence current effective value is an increasing trend.

[0099] Specifically, there is a period of time from the occurrence of a turn-to-turn fault in a 35kV reactor to the burning of the reactor, which is at least several hundred milliseconds. During this period, the ratio of the negative sequence current to the positive sequence current of the reactor is Increase slowly. According to the ratio of negative sequence current to positive sequence current of inter-turn fault Characteristics, so the ratio of the negative sequence current to the positive sequence current of the reactor Conduct follow-up judgment.

[0100] The judgment conditions are as follows:

[0101] The ratio of the current negative sequence current effective value to the positive sequence current effective value The ratio of the negative sequence current RMS value to the positive sequence current RMS value corresponding to the mth cycle before the wave The difference is greater than :

[0102]

[0103] For example, the current sampling point count n of the reactor protection device is 36, and m cycles take 1 cycle. The corresponding sampling point count 1 cycle ago is , in order to meet the sufficient sensitivity of inter-turn fault, The value is 0.01, that is, the discriminant formula of the ratio change trend condition is as follows:

[0104]

[0105] Taking the occurrence of a phase-to-phase turn-to-turn fault as an example, when the sampling point count is 36, the ratio of the negative sequence current RMS value to the positive sequence current RMS value is When the above formula is satisfied, the ratio of the negative sequence current effective value to the positive sequence current effective value when the sampling point count is 36 is considered to be The change trend meets the ratio change trend condition.

[0106] Specifically, step S110 includes the following steps:

[0107] Based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, it is determined whether the phase current change trend condition, the negative-sequence current change trend condition, the positive-sequence current change trend condition, and the ratio change trend condition are all satisfied;

[0108] If yes, it is determined that the inter-turn protection current change trend condition is met.

[0109] Specifically, step S112 includes: if the inter-turn protection start condition, inter-turn protection action condition, and inter-turn protection current change trend condition are met at the same sampling moment, then the target inter-turn protection action condition for that sampling point is met. If the target inter-turn protection action conditions corresponding to the number of sampling points are met for M consecutive milliseconds, the inter-turn protection trips.

[0110] Taking the occurrence of an ab phase-to-turn fault as an example, when the sampling point count reaches 36, the above target turn-to-turn protection action condition is met, and the timing judgment begins.

[0111] The number of sampling points corresponding to the M milliseconds after sampling point 36 all meet the target inter-turn protection action conditions, that is, the positive-sequence voltage remains basically unchanged, the phase a or phase b current continues to increase, the negative-sequence current continues to increase, the positive-sequence current continues to increase, and the ratio of the negative-sequence current to the positive-sequence current also continues to increase within M milliseconds. In this case, the inter-turn protection is activated.

[0112] Optionally, in this example, M milliseconds is twice the cycle time (1 cycle is 20 ms, corresponding to 24 sampling points N). That is, from sampling point count 36 to count 84 (36+48), each point satisfies the target inter-turn protection action condition, and the inter-turn protection trips.

[0113] As can be seen from the above description, the embodiment of the present invention provides a method for protecting a reactor from interturn faults by tracking the changing trends of voltage and current. The method uses a reactor protection device to collect the three-phase voltage and three-phase current connected to the reactor; calculates the corresponding positive-sequence voltage, three-phase current, positive-sequence current, and negative-sequence current; and makes a judgment based on the interturn fault characteristics of the 35kV reactor:

[0114] Based on the voltage characteristics of a 35kV reactor interturn fault, the following judgment is made: when an interturn fault occurs, the positive sequence voltage changes little. By tracking the trend of the positive sequence voltage remaining basically unchanged, it is determined whether the reactor has an interturn fault. If the positive sequence voltage remains basically unchanged, it is considered that the reactor may have an interturn fault. Further judgment is made on the current to accelerate the interturn protection action.

[0115] Based on the current characteristics of a 35kV reactor interturn fault, the following identification is performed: when an interturn fault occurs, the phase current, positive-sequence current, and negative-sequence current all slowly increase. By tracking the continuous increasing trend of the phase current, negative-sequence current, positive-sequence current, and the ratio of the negative-sequence current to the positive-sequence current, the current is considered to meet the interturn fault characteristics. When both the voltage and current characteristics are met, the interturn fault protection trips. This invention can quickly and accurately determine interturn faults in 35kV reactors, shortening the interturn fault clearance time.

[0116] Example 2

[0117] Figure 2Schematic diagram of a reactor turn-to-turn fault protection system for tracking voltage and current variation trends according to an embodiment of the present invention, which is applied to a reactor protection device of a 35kV power system. Figure 2 As shown, the system includes: a sampling module 10 , a calculation module 20 , a first judgment module 30 , a second judgment module 40 , a third judgment module 50 and a protection module 60 .

[0118] Specifically, the sampling module 10 is used to collect voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency.

[0119] The calculation module 20 is used to calculate the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value and the negative sequence current effective value based on the voltage sampling point data and the current sampling point data.

[0120] The first judgment module 30 is used to judge whether the inter-turn protection starting condition is met based on the positive sequence voltage effective value, the three-phase current effective value and the ratio of the negative sequence current effective value to the positive sequence current effective value.

[0121] The second judgment module 40 is configured to judge whether an inter-turn protection action condition is met based on a change trend of the positive sequence voltage effective value.

[0122] The third judgment module 50 is used to judge whether the inter-turn protection current change trend condition is met based on the three-phase current effective value, the negative sequence current effective value, the positive sequence current effective value and the ratio of the negative sequence current effective value to the positive sequence current effective value.

[0123] The protection module 60 is configured to control the reactor protection device to operate if the inter-turn protection start-up condition, the inter-turn protection action condition and the inter-turn protection current change trend condition are all satisfied within a preset sampling time.

[0124] Specifically, the calculation module 20 is also used to: convert the voltage sampling point data and the current sampling point data into voltage vector data and current vector data respectively through the full-cycle Fourier algorithm; and calculate the positive-sequence voltage effective value, the three-phase current effective value, the positive-sequence current effective value and the negative-sequence current effective value based on the voltage vector data and the current vector data.

[0125] Specifically, the inter-turn protection starting conditions include positive-sequence voltage conditions, three-phase current conditions and ratio conditions; among them, the positive-sequence voltage conditions include: the effective value of the positive-sequence voltage is greater than the first preset voltage threshold; the three-phase current conditions include: the effective values ​​of the three-phase currents are all greater than the preset no-current threshold; the ratio conditions include: the ratio of the effective value of the negative-sequence current to the effective value of the positive-sequence current is greater than the preset sensitivity coefficient.

[0126] Specifically, the first judgment module 30 is also used to: judge whether the positive-sequence voltage condition, the three-phase current condition and the ratio condition are all met based on the positive-sequence voltage effective value, the three-phase current effective value and the ratio of the negative-sequence current effective value to the positive-sequence current effective value; if so, determine that the inter-turn protection startup condition is met.

[0127] Specifically, the second judgment module 40 is further used to: judge whether the absolute value of the difference between the positive sequence voltage effective value corresponding to the current cycle and the positive sequence voltage effective value corresponding to the historical cycle is less than the second preset voltage threshold; if so, determine that the inter-turn protection action condition is met.

[0128] Specifically, the inter-turn protection current change trend conditions include phase current change trend conditions, negative-sequence current change trend conditions, positive-sequence current change trend conditions and ratio change trend conditions; wherein, the phase current change trend conditions include: the change trend of at least one phase current effective value among the three-phase current effective values ​​is an increasing trend; the negative-sequence current change trend conditions include: the change trend of the negative-sequence current effective value is an increasing trend; the positive-sequence current change trend conditions include: the change trend of the positive-sequence current effective value is an increasing trend; the ratio change trend conditions include: the change trend of the ratio of the negative-sequence current effective value to the positive-sequence current effective value is an increasing trend.

[0129] Specifically, the third judgment module 50 is also used to: based on the effective value of the three-phase current, the effective value of the negative-sequence current, the effective value of the positive-sequence current and the ratio of the effective value of the negative-sequence current to the effective value of the positive-sequence current, determine whether the phase current change trend condition, the negative-sequence current change trend condition, the positive-sequence current change trend condition and the ratio change trend condition are all met; if so, determine that the inter-turn protection current change trend condition is met.

[0130] The present invention also provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method provided in the embodiment of the present invention when executing the computer program.

[0131] The present invention also provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the method provided in the embodiment of the present invention is implemented.

[0132] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0133] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for protecting a reactor from inter-turn faults by tracking the changing trends of voltage and current, characterized in that: A reactor protection device applied to a 35kV power system; the method comprising: Collecting voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency; Calculating the positive-sequence voltage effective value, the three-phase current effective value, the positive-sequence current effective value, and the negative-sequence current effective value based on the voltage sampling point data and the current sampling point data; Determining whether a turn-to-turn protection startup condition is met based on the positive-sequence voltage effective value, the three-phase current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value; Based on the changing trend of the positive sequence voltage effective value, determining whether the inter-turn protection action condition is met; Based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, determining whether a turn-to-turn protection current change trend condition is met; If the inter-turn protection starting condition, the inter-turn protection action condition and the inter-turn protection current change trend condition are all met within the preset sampling time, the reactor protection device is controlled to operate.

2. The method according to claim 1, wherein: Calculating the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value, and the negative sequence current effective value based on the voltage sampling point data and the current sampling point data, including: Converting the voltage sampling point data and the current sampling point data into voltage vector data and current vector data respectively through a full-cycle Fourier algorithm; Based on the voltage vector data and the current vector data, a positive-sequence voltage effective value, a three-phase current effective value, a positive-sequence current effective value, and a negative-sequence current effective value are calculated.

3. The method according to claim 1, wherein: The inter-turn protection starting conditions include positive sequence voltage conditions, three-phase current conditions and ratio conditions; wherein, The positive sequence voltage condition includes: the positive sequence voltage effective value is greater than a first preset voltage threshold; The three-phase current condition includes: the effective values ​​of the three-phase currents are all greater than a preset no-current threshold; The ratio condition includes: a ratio of the negative sequence current effective value to the positive sequence current effective value is greater than a preset sensitivity coefficient.

4. The method according to claim 3, wherein: Determining whether a turn-to-turn protection startup condition is met based on the positive-sequence voltage effective value, the three-phase current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value includes: Based on the positive-sequence voltage effective value, the three-phase current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, determining whether the positive-sequence voltage condition, the three-phase current condition, and the ratio condition are all satisfied; If yes, it is determined that the inter-turn protection starting condition is met.

5. The method according to claim 1, wherein: Based on the change trend of the positive sequence voltage effective value, determining whether the turn-to-turn protection action condition is met includes: Determine whether the absolute value of the difference between the positive sequence voltage effective value corresponding to the current cycle and the positive sequence voltage effective value corresponding to the historical cycle is less than a second preset voltage threshold; If yes, it is determined that the inter-turn protection action condition is met.

6. The method according to claim 1, wherein: The inter-turn protection current change trend condition includes a phase current change trend condition, a negative sequence current change trend condition, a positive sequence current change trend condition and a ratio change trend condition; wherein, The phase current change trend condition includes: the change trend of at least one phase current effective value among the three-phase current effective values ​​is an increasing trend; The negative sequence current change trend condition includes: the change trend of the negative sequence current effective value is an increasing trend; The positive sequence current change trend condition includes: the change trend of the positive sequence current effective value is an increasing trend; The ratio change trend condition includes: the change trend of the ratio of the negative sequence current effective value to the positive sequence current effective value is an increasing trend.

7. The method according to claim 6, characterized in that: Judging whether a turn-to-turn protection current change trend condition is met based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value includes: Based on the three-phase current effective value, the negative-sequence current effective value, the positive-sequence current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value, determining whether the phase current change trend condition, the negative-sequence current change trend condition, the positive-sequence current change trend condition, and the ratio change trend condition are all satisfied; If yes, it is determined that the inter-turn protection current change trend condition is met.

8. A reactor inter-turn fault protection system that tracks voltage and current variation trends, characterized in that: A reactor protection device for a 35kV power system; comprising: a sampling module, a calculation module, a first judgment module, a second judgment module, a third judgment module and a protection module; wherein, The sampling module is used to collect voltage sampling point data and current sampling point data on the reactor protection device side based on a preset frequency; The calculation module is used to calculate the positive sequence voltage effective value, the three-phase current effective value, the positive sequence current effective value and the negative sequence current effective value based on the voltage sampling point data and the current sampling point data; The first judgment module is configured to judge whether a turn-to-turn protection startup condition is met based on the positive-sequence voltage effective value, the three-phase current effective value, and the ratio of the negative-sequence current effective value to the positive-sequence current effective value; The second judgment module is used to judge whether the inter-turn protection action condition is met based on the change trend of the positive sequence voltage effective value; The third judgment module is used to judge whether the inter-turn protection current change trend condition is met based on the three-phase current effective value, the negative sequence current effective value, the positive sequence current effective value, and the ratio of the negative sequence current effective value to the positive sequence current effective value; The protection module is used to control the reactor protection device to operate if the inter-turn protection start condition, the inter-turn protection action condition and the inter-turn protection current change trend condition are all met within a preset sampling time.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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