Reactor turn-to-turn fault protection method and system based on inductance value change rate

Abstract

The invention discloses an electric reactor turn-to-turn fault protection method and system based on an inductance value change rate, and the method comprises the steps: carrying out the sampling of a three-phase voltage and a three-phase current of an electric reactor, and obtaining a three-phase voltage sampling value and a three-phase current sampling value at a current sampling moment; calculating an inter-phase voltage effective value and an inter-phase inductance value based on the three-phase voltage sampling value and the three-phase current sampling value; calculating an inter-phase inductance change rate of any two phases based on the inter-phase inductance; judging whether the inter-phase voltage effective value and the inter-phase inductance change rate of any two phases meet a preset criterion or not; wherein for any two phases, if the change rate of the inter-phase inductance value of the any two phases is larger than a preset inductance change rate threshold value and the effective value of the inter-phase voltage of the any two phases is larger than a preset inter-phase voltage threshold value, it is determined that a preset criterion is met; when the phase current amplitude of the electric reactor is larger than a first preset current value, turn-to-turn protection is started, and when the duration meeting the preset criterion is larger than first preset time, turn-to-turn protection acts.

Description

Technical Field

[0001] The present invention relates to the technical field of power system protection and control, and more specifically, to a reactor turn-to-turn fault protection method and system based on inductance value change rate. Background Art

[0002] Dry-type air-core reactor is one of the important components of the power system, and its safe and reliable operation is crucial to the power grid. The expansion of the power grid capacity has rapidly increased the rated value of the system short-circuit capacity. For example, on the 35kV side of the 500kV substation, the maximum three-phase symmetrical short-circuit current effective value is close to 50kA. In order to limit the short-circuit current of the transmission line and protect the power equipment, the reactor must be installed. The reactor can reduce the short-circuit current and keep the voltage of the system unchanged at the moment of short circuit. The online monitoring of the reactor can grasp its operation, give early warning in time, and provide a basis for subsequent fault diagnosis and processing. The reactor protection device is the most effective means to achieve fast and reliable isolation of the reactor fault. The dry-type air-core reactor protection device uses current quick-break protection as the main protection and overcurrent protection as the backup protection. The current of the reactor increases when there is an inter-turn fault. Only when the fault develops to a very serious level can the overcurrent protection action setting be met. The overcurrent protection delays the action, and the action time is long, resulting in serious damage to the reactor. Therefore, for reactor protection, fast and sensitive identification of turn-to-turn protection is critical.

[0003] Therefore, a method for protecting the reactor from inter-turn faults based on the rate of change of inductance value is needed. Summary of the invention

[0004] The present invention provides a method and system for protecting a reactor from inter-turn faults based on an inductance value change rate, so as to solve the problem of how to determine the inter-turn fault protection for the reactor.

[0005] In order to solve the above problem, according to one aspect of the present invention, a method for protecting a reactor from turn-to-turn faults based on an inductance value change rate is provided, the method comprising: Sampling the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment; Calculating the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values; Calculating the interphase inductance change rate of any two phases based on the interphase inductance; Determine whether the effective value of the phase-to-phase voltage and the change rate of the phase-to-phase inductance of any two phases meet the preset criterion; wherein, for any two phases, if the change rate of the phase-to-phase inductance of the any two phases is greater than the preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of the any two phases is greater than the preset phase-to-phase voltage threshold value, then it is determined that the preset criterion is met; When the phase current amplitude of the reactor is greater than the first preset current value, the inter-turn protection is started, and when the duration of meeting the preset criterion is greater than the first preset time, the inter-turn protection is actuated; The interphase inductance change rate of any two phases is calculated using the following method, including: , in, , and The current sampling time The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; , and are the sampling times n cycles ago The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

[0006] Preferably, the calculating of the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values ​​comprises: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment are calculated; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

[0007] Preferably, the calculating of the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment comprises: , , in, , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding three-phase voltage phasor values; , and The current sampling time The corresponding three-phase differential current phasor values.

[0008] Preferably, the method further comprises: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

[0009] Preferably, the method further comprises: When a turn-to-turn fault is determined to have occurred, if the rate of change of the phase-to-phase inductance satisfies , then determine and The common phase is the turn-to-turn short-circuit phase; in, , and are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

[0010] According to another aspect of the present invention, a reactor turn-to-turn fault protection system based on inductance value change rate is provided, the system comprising: The sampling unit is used to sample the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment; A phase-to-phase voltage and phase-to-phase inductance calculation unit, used to calculate the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values; a phase-to-phase inductance change rate calculation unit, configured to calculate the phase-to-phase inductance change rate of any two phases based on the phase-to-phase inductance; A fault determination unit is used to determine whether the effective value of the phase-to-phase voltage and the phase-to-phase inductance change rate of any two phases meet a preset criterion; wherein, for any two phases, if the phase-to-phase inductance change rate of the any two phases is greater than a preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of the any two phases is greater than a preset phase-to-phase voltage threshold value, then it is determined that the preset criterion is met; A protection unit, configured to start the inter-turn protection when the phase current amplitude of the reactor is greater than a first preset current value, and to actuate the inter-turn protection when the duration of satisfying the preset criterion is greater than a first preset time; The interphase inductance change rate of any two phases is calculated using the following method, including: , in, , and The current sampling time The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; , and are the sampling times n cycles ago The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

[0011] Preferably, the phase-to-phase voltage and phase-to-phase inductance calculation unit calculates the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values, including: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment are calculated; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

[0012] Preferably, the phase-to-phase voltage and phase-to-phase inductance calculation unit calculates the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment, including: , , in, , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding three-phase voltage phasor values; , and The current sampling time The corresponding three-phase differential current phasor values.

[0013] Preferably, the protection unit is further used for: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

[0014] Preferably, the system further comprises: The short-circuit phase determination unit is used to: when it is determined that a turn-to-turn fault occurs, if the change rate of the phase-to-phase inductance value satisfies , then determine and The common phase is the turn-to-turn short-circuit phase; in, , and are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

[0015] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any step of a method for protecting a reactor from turn-to-turn faults based on an inductance value change rate.

[0016] According to another aspect of the present invention, the present invention provides an electronic device, including: The computer-readable storage medium described above; and One or more processors are used to execute the program in the computer-readable storage medium.

[0017] The present invention provides a method and system for protecting the inter-turn fault of a reactor based on the inductance value change rate, comprising: sampling the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment; calculating the effective value of the phase-to-phase voltage and the phase-to-phase inductance value at the current sampling moment based on the three-phase voltage sampling value and the three-phase current sampling value; calculating the phase-to-phase inductance change rate of any two phases based on the phase-to-phase inductance; judging whether the effective value of the phase-to-phase voltage and the phase-to-phase inductance change rate of any two phases meet a preset criterion; wherein, for any two phases, if the phase-to-phase inductance value change rate of the any two phases is greater than a preset inductance change rate threshold value, and the phase-to-phase voltage effective value of the any two phases is greater than a preset phase-to-phase voltage threshold value, it is determined that the preset criterion is met; when the phase current amplitude of the reactor is greater than a first preset current value, the inter-turn protection is started, and when the duration of meeting the preset criterion is greater than a first preset time, the inter-turn protection is actuated. The present invention utilizes the characteristics of inductance change during inter-turn faults to realize the identification of inter-turn faults and can provide early warning more sensitively. The inter-turn protection can quickly remove the faulty reactor, and the action speed can be increased by 10 times to avoid serious damage to the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings: Figure 1 Flow chart of a reactor turn-to-turn fault protection method 100 based on inductance value change rate according to an embodiment of the present invention; Figure 2 A schematic diagram of a reactor turn-to-turn protection logic according to an embodiment of the present invention; Figure 3 A flowchart of reactor turn-to-turn short-circuit phase identification according to an embodiment of the present invention; Figure 4 is a schematic diagram of the effective value of the phase-to-phase voltage calculated according to an embodiment of the present invention; Figure 5 is a schematic diagram of an effective value of inter-phase differential current calculated according to an embodiment of the present invention; Figure 6 is a schematic diagram of interphase inductance values ​​calculated according to an embodiment of the present invention; Figure 7 is a schematic diagram of the change rate of the phase-to-phase inductance value calculated according to an embodiment of the present invention; Figure 8 Schematic diagram of the structure of a reactor turn-to-turn fault protection system 800 based on inductance value change rate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0020] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0021] In order to improve the rapidity of the reactor protection against inter-turn faults, it is ensured that the reactor inter-turn protection can be activated when there is a slight inter-turn fault. The patent of the present invention extracts the characteristics of the rate of change of the phase-to-phase inductance value of the reactor, and can quickly and sensitively identify inter-turn faults. This avoids the slow action of the inter-turn fault protection, which develops into a serious fault and causes damage to the reactor, and improves the overall performance of the reactor protection. The present invention only requires real-time voltage and current data, the inductance calculation is relatively simple, the amount of calculation is small, and it is not affected by the operating mode. After the fault is found, it can be removed in time.

[0022] Figure 1 FIG. 1 is a flow chart of a reactor turn-to-turn fault protection method 100 based on an inductance value change rate according to an embodiment of the present invention. Figure 1 As shown, the reactor turn-to-turn fault protection method based on the inductance value change rate provided by the embodiment of the present invention utilizes the characteristics of the inductance change during the turn-to-turn fault to realize the identification of the turn-to-turn fault, and can provide a more sensitive early warning. The turn-to-turn protection can quickly remove the faulty reactor, and the action speed can be increased by 10 times to avoid serious damage to the reactor. The reactor turn-to-turn fault protection method 100 based on the inductance value change rate provided by the embodiment of the present invention starts from step 101. In step 101, the three-phase voltage and three-phase current of the reactor are sampled to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling time.

[0023] In step 102, the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment are calculated based on the three-phase voltage sampling values ​​and the three-phase current sampling values.

[0024] Preferably, the calculating of the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values ​​comprises: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, calculate the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

[0025] Preferably, the calculating of the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment comprises: , , in, , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding three-phase voltage phasor values; , and The current sampling time The corresponding three-phase differential current phasor values.

[0026] In the present invention, in order to realize the reactor turn-to-turn fault protection, the first thing required is the collection of electrical quantities. The three-phase voltage and current at the time, where i is a natural number; , , is the three-phase voltage sampling value, , , is the three-phase current sampling value.

[0027] Then, based on the three-phase voltage sampling values ​​and the three-phase current sampling values, the effective value of the phase-to-phase voltage and the phase-to-phase inductance are calculated. The specific process is as follows: (1) Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment. The calculation formula is: (1) in, , , is the three-phase current differential sampling value; , , For the current The three-phase current sampling values ​​at the moment, , , is the previous sampling point The sampling value of . (2) Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm.

[0028] Specifically, take the sampling rate of 1200 Hz, that is, 24 sampling points per cycle as an example. According to the three-phase voltage sampling value of the reactor , , And three-phase current differential sampling value , , Using Fourier algorithm to obtain the phase value of three-phase voltage , , And the three-phase differential current phasor value , , , the calculation formula is: (2) (3) (3) Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, calculate the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment. The calculation formula is: (4) (5) in, , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding three-phase voltage phasor values; , and The current sampling time The corresponding three-phase differential current phasor values.

[0029] (4) For any two phases, the interphase inductance of the arbitrary two phases is determined based on the ratio of the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment. The calculation formula is: (6) in, , and The current sampling time The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase.

[0030] In step 103, the interphase inductance change rate of any two phases is calculated based on the interphase inductance.

[0031] The interphase inductance change rate of any two phases is calculated using the following method, including: , in, , and The current sampling time The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; , and are the sampling times n cycles ago The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

[0032] In the present invention, according to the phase-to-phase inductance of the reactor , , Calculate the rate of change of phase-to-phase inductance , , The specific calculation method is: Using the current sampling time Phase-to-phase inductance , , Subtract the sampling time n cycles ago Phase-to-phase inductance , , The absolute value of divided by the sampling time n cycles ago Phase-to-phase inductance , , The absolute value of is: (7) Where N is the number of sampling points per cycle.

[0033] In step 104, it is determined whether the effective value of the phase-to-phase voltage and the phase-to-phase inductance change rate of any two phases meet the preset criteria; wherein, for any two phases, if the phase-to-phase inductance value change rate of any two phases is greater than the preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of any two phases is greater than the preset phase-to-phase voltage threshold value, then it is determined that the preset criteria are met.

[0034] In the present invention, in order to improve the safety of the algorithm when there is an out-of-zone fault, a voltage blocking criterion is added. , , Greater than the preset inductance change rate threshold , and the effective value of phase-to-phase voltage , , Greater than the preset phase-to-phase voltage threshold When , it is considered that the reactor has a turn-to-turn fault. The calculation formula is: (8) (9) (10) In step 105, when the phase current amplitude of the reactor is greater than the first preset current value, the inter-turn protection is started, and when the duration of satisfying the preset criterion is greater than the first preset time, the inter-turn protection is activated.

[0035] Preferably, the method further comprises: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

[0036] Combination Figure 2 As shown, in the present invention, the turn-to-turn protection method adopts overcurrent starting, and the alarm is started when the phase current amplitude I exceeds k1 times the rated current (k1In, i.e., the second preset current value), and when the change rate of a certain phase-to-phase inductance value and the phase-to-phase voltage continue to be greater than the preset action threshold value for a duration greater than the second preset time T2, the device sends an alarm signal; when the phase current amplitude I exceeds k2 times the rated current (k2In, i.e., the first preset current value), the turn-to-turn protection is started, and when the change rate of a certain phase-to-phase inductance value and the phase-to-phase voltage continue to be greater than the preset threshold value for a duration greater than the first preset time T1, the turn-to-turn protection is activated.

[0037] Preferably, the method further comprises: When a turn-to-turn fault is determined to have occurred, if the rate of change of the phase-to-phase inductance satisfies , then determine and The common phase is the turn-to-turn short-circuit phase; in, , and are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

[0038] In the present invention, the phase with turn-to-turn short circuit can also be identified. For example, when the turn-to-turn short circuit occurs in phase A, equations (8) and (10) hold true, i.e., kL ABi ≈kL CAi >>kL Bci , that is, the interphase circuit containing the fault phase meets the action condition, and the interphase circuit not containing the fault phase does not meet the action condition. Therefore, the interphase inductance change rate is used to meet , to judge the short-circuit phase, where and The common phase is the turn-to-turn short-circuit phase.

[0039] In the present invention, S can be set to 10. At this time, the specific process of determining the short-circuited phase is as follows: Figure 3 shown.

[0040] The method of the present invention utilizes the change rate of the interphase inductance value of the reactor to accurately and effectively identify the interturn fault of the reactor. Thus, the problem that the reactor protection is slow to identify and remove the interturn fault only by overcurrent protection is solved, and the action speed can be increased by 10 times. At the same time, it can monitor online whether the reactor has an interturn fault, send out an alarm signal, and improve the safety of the reactor.

[0041] The following specifically illustrates the embodiments of the present invention. Taking the inter-turn fault of a reactor in an actual project as an example, the specific process includes: Step 1: Obtain voltage and current data of the reactor.

[0042] Step 2, performing calculations based on the acquired voltage and current data. Specifically, it includes: (1) Calculation of three-phase current differential value The sampling rate of the on-site recording is 1000Hz, that is, 20 sampling points per cycle. The three-phase current differential sampling value is calculated using formula (1) for each sampling point. Among them, , , is the three-phase current sampling value, and the three-phase current differential sampling value is calculated d , .

[0043] (2) Determination of the phasor of the three-phase voltage and current differential values According to the three-phase voltage sampling value of the reactor , , And three-phase current differential sampling value d , Use formula (2) and formula (3) to obtain the three-phase voltage phase value , , And the three-phase differential current phasor value , , .

[0044] (3) Calculate the phase difference of voltage and current between phases According to the three-phase voltage phasor value , , And the three-phase differential current phasor value , , , use formula (4) and formula (5) to calculate the effective value of the phase-to-phase voltage , , And the effective value of phase differential current , , The waveforms of the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current are as follows: Figure 4 and Figure 5 shown.

[0045] (4) Use the result of step (3) to calculate the phase-to-phase inductance value According to the effective value of the phase-to-phase voltage , , And the effective value of phase differential current , , , use formula (6) to calculate the phase-to-phase inductance of the reactor , , The obtained reactor phase-to-phase inductance value is as follows: Figure 6 shown.

[0046] (5) Using the result of (4), calculate the change in the phase-to-phase inductance value. According to the phase-to-phase inductance value of the reactor , , , use formula (7) to calculate the change rate of phase-to-phase inductance , , The obtained phase-to-phase inductance change rate is as follows: Figure 7 shown.

[0047] (6) Comprehensively realize turn-to-turn short circuit identification by using the inductance change rate and voltage lock Use formulas (8) to (10) to judge the inter-turn short circuit. That is, when the rate of change of the phase-to-phase inductance is , , Greater than the inductance change rate threshold , and the effective value of phase-to-phase voltage , , Greater than the phase-to-phase voltage threshold When , it is considered that the reactor has a turn-to-turn fault and the fault phase is phase A.

[0048] The inter-turn protection method proposed in the present invention uses the on-site set value and 1.5 times the rated current data to start the inter-turn protection, and if the phase-to-phase inductance value change rate and the phase-to-phase voltage are continuously greater than the threshold value for 40ms, the inter-turn protection will act 40ms after it is started.

[0049] Figure 8 FIG. 8 is a schematic diagram of a reactor turn-to-turn fault protection system 800 based on an inductance value change rate according to an embodiment of the present invention. Figure 8As shown, the reactor inter-turn fault protection system 800 based on inductance value change rate provided in an embodiment of the present invention includes: a sampling unit 801, a phase-to-phase voltage and phase-to-phase inductance calculation unit 802, a phase-to-phase inductance change rate calculation unit 803, a fault determination unit 804 and a protection unit 805.

[0050] Preferably, the sampling unit 801 is used to sample the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment.

[0051] Preferably, the phase-to-phase voltage and phase-to-phase inductance calculation unit 802 is used to calculate the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values.

[0052] Preferably, the phase-to-phase voltage and phase-to-phase inductance calculation unit 802 calculates the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values, including: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, calculate the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

[0053] Preferably, the phase-to-phase voltage and phase-to-phase inductance calculation unit 802 calculates the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment, including: , , in, , and The current sampling time The corresponding effective values ​​of the phase-to-phase voltages of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding three-phase voltage phasor values; , and The current sampling time The corresponding three-phase differential current phasor values.

[0054] Preferably, the inter-phase inductance change rate calculation unit 803 is used to calculate the inter-phase inductance change rate of any two phases based on the inter-phase inductance.

[0055] The interphase inductance change rate of any two phases is calculated using the following method, including: , in, , and The current sampling time The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; , and The current sampling time The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; , and are the sampling times n cycles ago The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

[0056] Preferably, the fault determination unit 804 is used to determine whether the effective value of the phase-to-phase voltage and the phase-to-phase inductance change rate of any two phases meet the preset criteria; wherein, for any two phases, if the phase-to-phase inductance value change rate of any two phases is greater than a preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of any two phases is greater than a preset phase-to-phase voltage threshold value, it is determined that the preset criteria are met.

[0057] Preferably, the protection unit 805 is used to start the inter-turn protection when the phase current amplitude of the reactor is greater than the first preset current value, and to actuate the inter-turn protection when the duration of satisfying the preset criterion is greater than the first preset time; Preferably, the protection unit 805 is further used for: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

[0058] Preferably, the system further comprises: The short-circuit phase determination unit is used to: when it is determined that a turn-to-turn fault occurs, if the change rate of the phase-to-phase inductance value satisfies , then determine and The common phase is the turn-to-turn short-circuit phase; in, , and are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

[0059] The reactor turn-to-turn fault protection system 800 based on inductance value change rate in the embodiment of the present invention corresponds to the reactor turn-to-turn fault protection method 100 based on inductance value change rate in another embodiment of the present invention, which will not be described in detail here.

[0060] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any step of a method for protecting a reactor from turn-to-turn faults based on an inductance value change rate.

[0061] According to another aspect of the present invention, the present invention provides an electronic device, including: The computer-readable storage medium described above; and One or more processors are used to execute the program in the computer-readable storage medium.

[0062] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0063] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise therein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of said means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0064] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0065] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0066] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0067] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for protecting a reactor from inter-turn faults based on an inductance value change rate, characterized in that: The method comprises: Sampling the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment; Calculating the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values; Calculating the interphase inductance change rate of any two phases based on the interphase inductance; Determine whether the effective value of the phase-to-phase voltage and the change rate of the phase-to-phase inductance of any two phases meet the preset criterion; wherein, for any two phases, if the change rate of the phase-to-phase inductance of the any two phases is greater than the preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of the any two phases is greater than the preset phase-to-phase voltage threshold value, then it is determined that the preset criterion is met; When the phase current amplitude of the reactor is greater than the first preset current value, the inter-turn protection is started, and when the duration of meeting the preset criterion is greater than the first preset time, the inter-turn protection is actuated; The interphase inductance change rate of any two phases is calculated using the following method, including: Among them, kL ABi , kL BCi and kL CAi are the current sampling time t i The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; L ABi , L BCi and L CAi are the current sampling time t i The corresponding phase-to-phase inductance values ​​of AB phase, BC phase and AC phase; L ABi-n*N , L BCi-n*N and L CAi-n*N are the sampling times t n cycles ago i-n*N The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

2. The method according to claim 1, characterized in that The calculating the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values ​​includes: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, calculate the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

3. The method according to claim 2, characterized in that The method of calculating the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment includes: Among them, U ABi , U BCi and U CAi are the current sampling time t i The corresponding phase-to-phase voltage effective value of AB phase, BC phase and AC phase; dI ABi ,dI BCi and dI CAi are the current sampling time t i The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; and is the current sampling time t i The corresponding three-phase voltage phasor values; and is the current sampling time t i The corresponding three-phase differential current phasor values.

4. The method according to claim 1, characterized in that: The method further comprises: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

5. The method according to claim 1, characterized in that: The method further comprises: When it is determined that a turn-to-turn fault has occurred, if the rate of change of the phase-to-phase inductance satisfies (kL φφ1 +kL φφ2 ) / kL φφ3 >S, then determine kL φφ1 and kL φφ2 The common phase is the turn-to-turn short-circuit phase; Among them, kL φφ1 , kL φφ2 and kL φφ3 are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

6. A reactor turn-to-turn fault protection system based on inductance value change rate, characterized in that: The system comprises: The sampling unit is used to sample the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling value and the three-phase current sampling value at the current sampling moment; A phase-to-phase voltage and phase-to-phase inductance calculation unit, used to calculate the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values; a phase-to-phase inductance change rate calculation unit, configured to calculate the phase-to-phase inductance change rate of any two phases based on the phase-to-phase inductance; A fault determination unit is used to determine whether the effective value of the phase-to-phase voltage and the phase-to-phase inductance change rate of any two phases meet a preset criterion; wherein, for any two phases, if the phase-to-phase inductance change rate of the any two phases is greater than a preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage of the any two phases is greater than a preset phase-to-phase voltage threshold value, then it is determined that the preset criterion is met; A protection unit, configured to start the inter-turn protection when the phase current amplitude of the reactor is greater than a first preset current value, and to actuate the inter-turn protection when the duration of satisfying the preset criterion is greater than a first preset time; The interphase inductance change rate of any two phases is calculated using the following method, including: Among them, kL ABi , kL BCi and kL CAi are the current sampling time t i The corresponding change rate of the phase-to-phase inductance of the AB phase, BC phase and AC phase; L ABi , L BCi and L CAi are the current sampling time t i The corresponding phase-to-phase inductance values ​​of AB phase, BC phase and AC phase; L ABi-n*N , L BCi-n*N and L CAi-n*N are the sampling times t n cycles ago i-n*N The corresponding interphase inductance values ​​of AB phase, BC phase and AC phase; N is the number of sampling points per cycle.

7. The system according to claim 6, characterized in that The phase-to-phase voltage and phase-to-phase inductance calculation unit calculates the effective value of the phase-to-phase voltage and the phase-to-phase inductance at the current sampling moment based on the three-phase voltage sampling values ​​and the three-phase current sampling values, including: Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling value at the current sampling moment and the three-phase current sampling value at the previous sampling moment; Based on the three-phase voltage sampling values ​​and the three-phase current differential sampling values ​​at the current sampling moment, the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment are calculated using the Fourier algorithm; Based on the three-phase voltage phasor values ​​and the three-phase differential current phasor values ​​at the current sampling moment, calculate the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment; For any two phases, the interphase inductance value of the arbitrary two phases is determined based on the ratio of the interphase voltage effective value and the interphase differential current effective value of the arbitrary two phases at the current sampling moment.

8. The system according to claim 7, characterized in that The phase-to-phase voltage and phase-to-phase inductance calculation unit calculates the effective value of the phase-to-phase voltage and the effective value of the phase-to-phase differential current at the current sampling moment based on the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment, including: Among them, U ABi , U BCi and U CAi are the effective values ​​of the phase-to-phase voltages of AB phase, BC phase and AC phase corresponding to the current sampling time ti; dI ABi ,dI BCi and dI CAi are the current sampling time t i The corresponding inter-phase differential current effective value of the AB phase, BC phase and AC phase; and is the current sampling time t i The corresponding three-phase voltage phasor values; and is the three-phase differential current phasor value corresponding to the current sampling time ti.

9. The system according to claim 6, characterized in that The protection unit is further used for: When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is activated, and when the duration of meeting the preset criterion is greater than the second preset time, the turn-to-turn fault alarm signal is issued.

10. The system according to claim 6, characterized in that The system further comprises: The short-circuit phase determination unit is used to: when it is determined that a turn-to-turn fault occurs, if the change rate of the phase-to-phase inductance value satisfies (kL φφ1 +kL φφ2 ) / kL φφ3 >S, then determine kL φφ1 and kL φφ2 The common phase is the turn-to-turn short-circuit phase; Among them, kL φφ1 , kL φφ2 and kL φφ3 are the rates of change of the interphase inductance of any two phases, φφ takes values ​​of AB, BC and AC; S is the fault phase identification coefficient.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

12. An electronic device, characterized in that: include: The computer readable storage medium as claimed in claim 11; as well as One or more processors are used to execute the program in the computer-readable storage medium.

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