A reactor turn-to-turn fault protection method and system based on the rate of change of inductance value

Abstract

The present invention discloses a method and system for inter-turn fault protection of a reactor based on the change rate of inductance value, including: sampling the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling values and three-phase current sampling values at the current sampling moment; calculating the effective value of the phase-to-phase voltage and the phase-to-phase inductance value based on the three-phase voltage sampling values and three-phase current sampling values; calculating the change rate of the phase-to-phase inductance between any two phases based on the phase-to-phase inductance; determining whether the effective value of the phase-to-phase voltage and the change rate of the phase-to-phase inductance between any two phases satisfy a preset criterion; wherein, for any two phases, if the change rate of the phase-to-phase inductance value between the any two phases is greater than a preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage between the any two phases is greater than a preset phase-to-phase voltage threshold value, it is determined that the preset criterion is satisfied; 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 for satisfying the preset criterion is greater than a first preset time, the inter-turn protection operates.

Description

Technical Field

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

[0002] The dry-type air-core reactor is one of the important components of the power system, and its safe and reliable operation is crucial for the power grid. The expansion of the power grid capacity has rapidly increased the rated value of the system short-circuit capacity. For example, at the 35kV side of a 500kV substation, the effective value of the maximum three-phase symmetrical short-circuit current has approached 50kA. In order to limit the short-circuit current of the transmission line and protect power equipment, a 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 on-line monitoring of the reactor can master its operating conditions, give early warnings in time, and provide a basis for subsequent fault diagnosis and treatment. The reactor protection device is the most effective means to achieve fast and reliable isolation of reactor faults. The dry-type air-core reactor protection device mainly uses current quick-break protection as the main protection and over-current protection as the backup protection. When there is an inter-turn fault in the reactor, the current increases. Only when the fault develops to a very serious level does it meet the action setting value of the over-current protection, and the over-current protection acts with a time delay, and the action time is relatively long, resulting in serious damage to the reactor. Therefore, for reactor protection, it is very crucial to quickly and sensitively identify inter-turn protection.

[0003] Therefore, a method for inter-turn fault protection of a reactor based on the rate of change of inductance value is needed. Summary of the Invention

[0004] The present invention proposes a method and system for inter-turn fault protection of a reactor based on the rate of change of inductance value to solve the problem of how to determine the inter-turn fault protection of the reactor.

[0005] To solve the above problems, according to one aspect of the present invention, a method for inter-turn fault protection of a reactor based on the rate of change of inductance value is provided. The method includes:

[0006] Sampling the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling values and three-phase current sampling values at the current sampling moment;

[0007] 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 values and three-phase current sampling values;

[0008] Calculating the rate of change of the phase-to-phase inductance between any two phases based on the phase-to-phase inductance;

[0009] Determine whether the effective value of the phase-to-phase voltage and the change rate of the phase-to-phase inductance between any two phases meet the preset criteria; wherein, for any two phases, if the change rate of the phase-to-phase inductance value between the any two phases is greater than the preset inductance change rate threshold value, and the effective value of the phase-to-phase voltage between the any two phases is greater than the preset phase-to-phase voltage threshold value, it is determined that the preset criteria are met;

[0010] When the phase current amplitude of the reactor is greater than the first preset current value, the turn-to-turn protection starts, and when the duration for meeting the preset criteria is greater than the first preset time, the turn-to-turn protection operates;

[0011] Among them, the change rate of the phase-to-phase inductance between any two phases is calculated by the following method, including:

[0012] ,

[0013] Among them, , and are respectively the change rates of the phase-to-phase inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; , and are respectively the phase-to-phase inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; , and are respectively the phase-to-phase inductance values of the AB phase, BC phase and AC phase corresponding to the sampling moment n cycle waves ago; N is the number of sampling points per cycle wave.

[0014] Preferably, the calculation of 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 values and the three-phase current sampling values includes:

[0015] Determine the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling values at the current sampling moment and the three-phase current sampling values at the previous sampling moment;

[0016] Based on the three-phase voltage sampling values and the three-phase current differential sampling values at the current sampling moment, use the Fourier algorithm to calculate the three-phase voltage phasor value and the three-phase differential current phasor value at the current sampling moment;

[0017] Based on the three-phase voltage phasor value and the three-phase differential current phasor value 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;

[0018] For any two phases, determine the phase-to-phase inductance value of the any two phases 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 of the any two phases at the current sampling moment.

[0019] Preferably, 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:

[0020] ,

[0021] ,

[0022] wherein, 、 and are respectively the effective values of the phase - to - phase voltages of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; 、 and are respectively the effective values of the phase - to - phase differential currents of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; 、 and are the three - phase voltage phasor values corresponding to the current sampling moment ; 、 and are the three - phase differential current phasor values corresponding to the current sampling moment .

[0023] Preferably, the method further includes:

[0024] When the phase - current amplitude of the reactor is greater than the second preset current value, the turn - to - turn fault alarm is started, and when the duration satisfying the preset criterion is greater than the second preset time, a turn - to - turn fault alarm signal is issued.

[0025] Preferably, the method further includes:

[0026] When it is determined that a turn - to - turn fault has occurred, if the change rate of the inter - phase inductance value satisfies , then it is determined that and 's common phase is the turn - to - turn short - circuit phase;

[0027] wherein, 、 and are respectively the change rates of the inter - phase inductance values of any two phases, φφ takes values of AB, BC, and AC; S is the fault - phase identification coefficient.

[0028] According to another aspect of the present invention, a turn - to - turn fault protection system for a reactor based on the change rate of inductance value is provided, and the system includes:

[0029] A sampling unit, configured to sample the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling values and three-phase current sampling values at the current sampling moment;

[0030] An inter-phase voltage and inter-phase inductance calculation unit, configured to calculate the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment based on the three-phase voltage sampling values and three-phase current sampling values;

[0031] An inter-phase inductance change rate calculation unit, configured to calculate the inter-phase inductance change rate of any two phases based on the inter-phase inductance;

[0032] A fault determination unit, configured to determine whether the effective value of the inter-phase voltage and the inter-phase inductance change rate of any two phases meet a preset criterion; wherein, for any two phases, if the change rate of the inter-phase inductance value of the any two phases is greater than a preset inductance change rate threshold value, and the effective value of the inter-phase voltage of the any two phases is greater than a preset inter-phase voltage threshold value, it is determined that the preset criterion is met;

[0033] A protection unit, configured to start turn-to-turn protection when the phase current amplitude of the reactor is greater than a first preset current value, and to actuate the turn-to-turn protection when the duration for meeting the preset criterion is greater than a first preset time;

[0034] Wherein, the inter-phase inductance change rate of any two phases is calculated by the following method, including:

[0035] ,

[0036] Wherein, 、 and are respectively the inter-phase inductance value change rates of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the inter-phase inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the inter-phase inductance values of the AB phase, BC phase and AC phase corresponding to the sampling moment n cycle waves ago; N is the number of sampling points per cycle wave.

[0037] Preferably, the inter-phase voltage and inter-phase inductance calculation unit calculates the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment based on the three-phase voltage sampling values and three-phase current sampling values, including:

[0038] Determining the three-phase current differential sampling value at the current sampling moment based on the three-phase current sampling values at the current sampling moment and the three-phase current sampling values at the previous sampling moment;

[0039] Based on the three-phase voltage sampling values and the three-phase current differential sampling values at the current sampling moment, use the Fourier algorithm to calculate the three-phase voltage phasor values and the three-phase differential current phasor values at the current sampling moment;

[0040] Based on the three-phase voltage phasor values and the three-phase differential current phasor values at the current sampling moment, calculate the effective values of the line-to-line voltages and the effective values of the line-to-line differential currents at the current sampling moment;

[0041] For any two phases, based on the ratio of the effective value of the line-to-line voltage and the effective value of the line-to-line differential current of the any two phases at the current sampling moment, determine the line-to-line inductance value of the any two phases.

[0042] Preferably, the line-to-line voltage and line-to-line inductance calculation unit, based on the three-phase voltage phasor values and the three-phase differential current phasor values at the current sampling moment, calculates the effective values of the line-to-line voltages and the effective values of the line-to-line differential currents at the current sampling moment, including:

[0043] ,

[0044] ,

[0045] wherein, , and are respectively the effective values of the line-to-line voltages of the AB phase, BC phase and AC phase corresponding to at the current sampling moment; , and are respectively the effective values of the line-to-line differential currents of the AB phase, BC phase and AC phase corresponding to at the current sampling moment; , and are the three-phase voltage phasor values corresponding to at the current sampling moment; , and are the three-phase differential current phasor values corresponding to at the current sampling moment.

[0046] Preferably, the protection unit is further configured to:

[0047] When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is started, and when the duration satisfying the preset criterion is greater than the second preset time, a turn-to-turn fault alarm signal is issued.

[0048] Preferably, the system further includes:

[0049] A short - circuit phase determination unit, configured to: when it is determined that an inter - turn fault has occurred, if the rate of change of the inter - phase inductance value satisfies , then determine and the common phase of

[0050] as the inter - turn short - circuit phase; , and are respectively the rates of change of the inter - phase inductance values of any two phases, where φφ takes values of AB, BC, and AC; S is the fault phase identification coefficient.

[0051] On the other hand of the present invention, the present invention provides a computer - readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps of any one of the reactor inter - turn fault protection methods based on the rate of change of inductance value.

[0052] On the other hand of the present invention, the present invention provides an electronic device, including:

[0053] The above - mentioned computer - readable storage medium; and

[0054] One or more processors for executing the program in the computer - readable storage medium.

[0055] The present invention provides a reactor inter - turn fault protection method and system based on the rate of change of inductance value, including: sampling the three - phase voltage and three - phase current of the reactor to obtain the three - phase voltage sampling values and three - phase current sampling values at the current sampling moment; calculating the effective value of the inter - phase voltage and the inter - phase inductance value at the current sampling moment based on the three - phase voltage sampling values and three - phase current sampling values; calculating the rate of change of the inter - phase inductance of any two phases based on the inter - phase inductance; determining whether the effective value of the inter - phase voltage and the rate of change of the inter - phase inductance of any two phases satisfy a preset criterion; where, for any two phases, if the rate of change of the inter - phase inductance value of the any two phases is greater than a preset inductance change rate threshold value, and the effective value of the inter - phase voltage of the any two phases is greater than a preset inter - phase voltage threshold value, then it is determined that the preset criterion is satisfied; when the amplitude of the phase current of the reactor is greater than a first preset current value, the inter - turn protection is started, and when the duration for which the preset criterion is satisfied is greater than a first preset time, the inter - turn protection operates. The present invention utilizes the characteristics of inductance change during an inter - turn fault to realize the identification of inter - turn faults, can give a relatively sensitive early warning, the inter - turn protection can quickly operate to cut off the faulty reactor, and the operation speed can be increased by 10 times, avoiding serious damage to the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] By referring to the following drawings, the exemplary embodiments of the present invention can be more completely understood:

[0057] Figure 1Flow chart of the reactor turn - to - turn fault protection method 100 based on the rate of change of inductance value according to an embodiment of the present invention;

[0058] Figure 2 Schematic diagram of the reactor turn - to - turn protection logic according to an embodiment of the present invention;

[0059] Figure 3 Flow chart of the identification of the short - circuited phase of the reactor turn - to - turn according to an embodiment of the present invention;

[0060] Figure 4 Schematic diagram of the effective value of the phase - to - phase voltage calculated according to an embodiment of the present invention;

[0061] Figure 5 Schematic diagram of the effective value of the phase - to - phase differential current calculated according to an embodiment of the present invention;

[0062] Figure 6 Schematic diagram of the phase - to - phase inductance value calculated according to an embodiment of the present invention;

[0063] Figure 7 Schematic diagram of the rate of change of the phase - to - phase inductance value calculated according to an embodiment of the present invention;

[0064] Figure 8 Schematic diagram of the structure of the reactor turn - to - turn fault protection system 800 based on the rate of change of inductance value according to an embodiment of the present invention. Detailed implementation manners

[0065] Now, exemplary embodiments of the present invention will be introduced 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 in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0066] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. Additionally, it can be understood that the terms defined in a commonly used dictionary should be understood as having a meaning consistent with the context of their related fields, and should not be understood as having an idealized or overly formal meaning.

[0067] In order to improve the operation speed of the reactor protection against turn-to-turn faults and ensure that the turn-to-turn protection of the reactor can operate in the event of a minor turn-to-turn fault. This invention patent extracts the characteristics of the change rate of the inter-phase inductance value of the reactor, and can quickly and sensitively identify turn-to-turn faults. Thus, it can avoid the slow operation of the turn-to-turn fault protection and the development of a serious fault leading to the damage of the reactor, and improve the overall performance of the reactor protection. This invention only requires real-time voltage and current data, the inductance calculation is relatively simple, the amount of calculation is small, it is not affected by the operation mode, and it can operate and cut off in time after a fault is detected.

[0068] Figure 1 FIG. is a flowchart of a reactor turn-to-turn fault protection method 100 based on the change rate of inductance value according to an embodiment of the present invention. As Figure 1 shown, the reactor turn-to-turn fault protection method based on the change rate of inductance value provided by the embodiment of the present invention utilizes the characteristics of inductance change during turn-to-turn faults to achieve the identification of turn-to-turn faults, can give a relatively sensitive early warning, the turn-to-turn protection can quickly operate to cut off the faulty reactor, and the operation speed can be increased by 10 times, avoiding serious damage to the reactor. The reactor turn-to-turn fault protection method 100 based on the change rate of inductance value 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 values and three-phase current sampling values at the current sampling moment.

[0069] In step 102, based on the three-phase voltage sampling values and three-phase current sampling values, the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment are calculated.

[0070] Preferably, the calculating the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment based on the three-phase voltage sampling values and three-phase current sampling values includes:

[0071] Determining the three-phase current differential sampling values at the current sampling moment based on the three-phase current sampling values at the current sampling moment and the three-phase current sampling values at the previous sampling moment;

[0072] Based on the three-phase voltage sampling values and three-phase current differential sampling values at the current sampling moment, using the Fourier algorithm to calculate the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment;

[0073] Based on the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment, calculating the effective value of the inter-phase voltage and the effective value of the inter-phase differential current at the current sampling moment;

[0074] For any two phases, based on the ratio of the effective value of the inter-phase voltage and the effective value of the inter-phase differential current of the two phases at the current sampling moment, determining the inter-phase inductance value of the two phases.

[0075] Preferably, 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:

[0076] ,

[0077] ,

[0078] wherein, 、 and are respectively the effective values of the phase - to - phase voltages of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; 、 and are respectively the effective values of the phase - to - phase differential currents of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; 、 and are the three - phase voltage phasor values corresponding to the current sampling moment ; 、 and are the three - phase differential current phasor values corresponding to the current sampling moment .

[0079] In the present invention, in order to implement the inter - turn fault protection of the reactor, the first thing needed is the acquisition of electrical quantities. In the present invention, the three - phase voltage and current of the reactor at the moment are collected, where i is a natural number; 、 、 are the three - phase voltage sampling values, 、 、 are the three - phase current sampling values.

[0080] Then, based on the three - phase voltage sampling values and the three - phase current sampling values, calculations are performed to calculate the effective value of the phase - to - phase voltage and the value of the phase - to - phase inductance. The specific process is as follows:

[0081] (1) Determine the three - phase current differential sampling values at the current sampling moment based on the three - phase current sampling values at the current sampling moment and the three - phase current sampling values at the previous sampling moment. The calculation formula is:

[0082] (1)

[0083] wherein, 、 、 are the three - phase current differential sampling values; 、 , is the three-phase current sampling value at the current moment, , , and are the sampling values at the previous sampling point moment.

[0084] (2) Based on the three-phase voltage sampling values and three-phase current differential sampling values at the current sampling moment, use the Fourier algorithm to calculate the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment.

[0085] Specifically, taking the sampling rate of 1200 Hz, that is, 24 points sampling per cycle as an example. Then, according to the three-phase voltage sampling values , , of the reactor and the three-phase current differential sampling values , , use the Fourier algorithm to obtain the three-phase voltage phasor values , , and the three-phase differential current phasor values , , . The calculation formula is:

[0086] (2)

[0087] (3)

[0088] (3) Based on the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment, calculate the effective values of the phase-to-phase voltages and phase-to-phase differential currents at the current sampling moment. The calculation formula is:

[0089] (4)

[0090] (5)

[0091] Among them, , and are respectively the effective values of the phase-to-phase voltages of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are respectively the effective values of the phase-to-phase differential currents of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are at the current sampling moment The corresponding three-phase voltage phasor values; 、 and are the three-phase differential current phasor values corresponding to the current sampling moment

[0092] (4) For any two phases, based on the ratio of the effective value of the line voltage and the effective value of the line differential current of the two phases at the current sampling moment, determine the line inductance value of the two phases. The calculation formula is:

[0093] (6)

[0094] Wherein, 、 and are respectively the line inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the effective values of the line voltages of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the effective values of the line differential currents of the AB phase, BC phase and AC phase corresponding to the current sampling moment

[0095] In step 103, calculate the line inductance change rate of any two phases based on the line inductance.

[0096] Wherein, calculate the line inductance change rate of any two phases in the following manner, including:

[0097] ,

[0098] Wherein, 、 and are respectively the change rates of the line inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the line inductance values of the AB phase, BC phase and AC phase corresponding to the current sampling moment ; 、 and are respectively the line inductance values of the AB phase, BC phase and AC phase corresponding to the sampling moment n cycles ago; N is the number of sampling points per cycle.

[0099] ​​In the present invention, according to the inter-phase inductance values of the reactors , , calculate the change rate of the inter-phase inductance value , , . The specific calculation method is as follows:

[0100] Use the inter-phase inductance values at the current sampling moment , , subtract the inter-phase inductance values at the sampling moment n cycles ago , , . Divide the absolute value of the result by the absolute value of the inter-phase inductance values at the sampling moment n cycles ago , , , that is:

[0101] (7)

[0102] where N is the number of sampling points per cycle.

[0103] In step 104, determine whether the effective values of the inter-phase voltages and the change rate of the inter-phase inductance of any two phases satisfy a preset criterion; for any two phases, if the change rate of the inter-phase inductance value of the two phases is greater than a preset inductance change rate threshold value, and the effective value of the inter-phase voltage of the two phases is greater than a preset inter-phase voltage threshold value, it is determined that the preset criterion is satisfied.

[0104] In the present invention, in order to improve the safety of the algorithm during an external fault, a voltage blocking criterion is added. That is, when the change rate of the inter-phase inductance value , , is greater than a preset inductance change rate threshold value , and the effective value of the inter-phase voltage , , is greater than a preset inter-phase voltage threshold value , it is considered that a turn-to-turn fault has occurred in the reactor. The calculation formula is:

[0105] (8)

[0106] (9)

[0107] (10)

[0108] In step 105, when the phase current amplitude of the reactor is greater than the first preset current value, the turn-to-turn protection is started, and when the duration satisfying the preset criterion is greater than the first preset time, the turn-to-turn protection operates.

[0109] Preferably, the method further includes:

[0110] When the phase current amplitude of the reactor is greater than the second preset current value, the turn-to-turn fault alarm is started, and when the duration satisfying the preset criterion is greater than the second preset time, a turn-to-turn fault alarm signal is issued.

[0111] Combined with Figure 2 As shown, in the present invention, the turn-to-turn protection method adopts overcurrent startup. When the phase current amplitude I exceeds k 1 times (k 1 In, that is, the second preset current value) of the rated current, the alarm is started, and when the duration that the change rate of the inductance value between a certain two phases and the voltage between phases continuously is greater than the preset action threshold value is greater than the second preset time T2, the device issues an alarm signal; when the phase current amplitude I exceeds k 2 times the rated current (k 2 In, that is, the first preset current value), the turn-to-turn protection is started, and when the duration that the change rate of the inductance value between a certain two phases and the voltage between phases continuously is greater than the preset threshold value is greater than the first preset time T1, the turn-to-turn protection operates.

[0112] Preferably, the method further includes:

[0113] When it is determined that a turn-to-turn fault has occurred, if the change rate of the inductance value between phases satisfies , then it is determined that and the common phase of is the turn-to-turn short-circuit phase;

[0114] Wherein, , and are the change rates of the inductance values between any two phases respectively, and φφ takes values of AB, BC, and AC; S is the fault phase identification coefficient.

[0115] In the present invention, the phase of the turn-to-turn short circuit can also be identified. For example, when there is a turn-to-turn short circuit in phase A, equations (8) and (10) hold, that is, kL ABi ≈kL CAi >>kL Bci , that is, the phase loop including the fault phase satisfies the action condition, and the phase loop not including the fault phase does not satisfy the action condition. Therefore, by using the change rate of the inductance value between phases satisfying , the short-circuit phase is judged, where and the common phase of is the turn-to-turn short-circuit phase.

[0116] In the present invention, S can be set to 10. At this time, the specific process for determining the short - circuited phase is as follows Figure 3 as shown.

[0117] The method of the present invention utilizes the rate of change of the inter - phase inductance value of the reactor to accurately and effectively identify the turn - to - turn fault of the reactor. Thus, it solves the problem that the reactor protection relies only on over - current protection to identify and cut off the turn - to - turn fault with slow action. The action speed can be increased by 10 times. At the same time, it can on - line monitor whether the reactor has a turn - to - turn fault and send out an alarm signal, improving the safety of the reactor.

[0118] The following specifically illustrates the implementation mode of the present invention

[0119] Taking the turn - to - turn fault of the reactor in a certain actual project as an example, the specific process includes:

[0120] Step 1: Obtain the voltage and current data of the reactor.

[0121] Step 2: Calculate according to the obtained voltage and current data. Specifically, it includes:

[0122] (1) Calculation of the three - phase current difference value

[0123] The on - site recording wave sampling rate is 1000 Hz, that is, 20 points are sampled per cycle. The three - phase current difference sampling values are calculated for each sampling point using formula (1). Among them, , , are the three - phase current sampling values, and the three - phase current difference sampling values d , are calculated.

[0124] (2) Calculation of the phasors of the three - phase voltage and current difference values

[0125] According to the three - phase voltage sampling values , , of the reactor and the three - phase current difference sampling values d , the three - phase voltage phasor values , , and the three - phase differential current phasor values , , are calculated using formula (2) and formula (3).

[0126] (3) Calculate the phasors of the inter - phase voltage and current difference values

[0127] According to the three - phase voltage phasor values , , and the three-phase differential current phasor values 、 、 , use Formula (4) and Formula (5) to obtain the effective value of the line-to-line voltage 、 、 and the effective value of the line-to-line differential current 、 、 . The waveforms of the obtained effective value of the line-to-line voltage and the effective value of the line-to-line differential current are respectively as shown in Figure 4 and Figure 5 .

[0128] (4) Use the result of step (3) to obtain the line-to-line inductance value

[0129] According to the effective value of the line-to-line voltage 、 、 and the effective value of the line-to-line differential current 、 、 , use Formula (6) to obtain the line-to-line inductance value of the reactor 、 、 . The obtained line-to-line inductance value of the reactor is as shown in Figure 6 .

[0130] (5) Use the result of (4) to calculate the change in the line-to-line inductance value

[0131] According to the line-to-line inductance value of the reactor 、 、 , use Formula (7) to obtain the rate of change of the line-to-line inductance value 、 、 . The obtained rate of change of the line-to-line inductance is as shown in Figure 7 .

[0132] (6) Use the rate of change of the inductance value and voltage blocking to comprehensively implement the inter-turn short circuit discrimination

[0133] Use Formulas (8) to (10) for inter-turn short circuit discrimination. That is, when the rate of change of the line-to-line inductance value 、 、 is greater than the threshold value of the rate of change of the inductance , and the effective value of the line-to-line voltage 、 、 is greater than the threshold value of the line-to-line voltage , it is considered that an inter-turn fault has occurred in the reactor, and the faulty phase is Phase A.

[0134] The inter-turn protection method proposed by the present invention uses on-site setting values and 1.5 times the rated current data to start the inter-turn protection. When the rate of change of the inter-phase inductance value and the inter-phase voltage continuously exceed the threshold value for 40 ms, the protection will operate 40 ms after the inter-turn protection is started.

[0135] Figure 8 FIG. 4 is a schematic structural diagram of a reactor inter-turn fault protection system 800 based on the rate of change of inductance value according to an embodiment of the present invention. As Figure 8 shown, the reactor inter-turn fault protection system 800 based on the rate of change of inductance value provided by the embodiment of the present invention includes: a sampling unit 801, an inter-phase voltage and inter-phase inductance calculation unit 802, an inter-phase inductance change rate calculation unit 803, a fault determination unit 804, and a protection unit 805.

[0136] Preferably, the sampling unit 801 is configured to sample the three-phase voltage and three-phase current of the reactor to obtain the three-phase voltage sampling values and three-phase current sampling values at the current sampling moment.

[0137] Preferably, the inter-phase voltage and inter-phase inductance calculation unit 802 is configured to calculate the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment based on the three-phase voltage sampling values and three-phase current sampling values.

[0138] Preferably, the inter-phase voltage and inter-phase inductance calculation unit 802 calculates the effective value of the inter-phase voltage and the inter-phase inductance value at the current sampling moment based on the three-phase voltage sampling values and three-phase current sampling values, including:

[0139] Determining the three-phase current differential sampling values at the current sampling moment based on the three-phase current sampling values at the current sampling moment and the three-phase current sampling values at the previous sampling moment;

[0140] Based on the three-phase voltage sampling values and three-phase current differential sampling values at the current sampling moment, using the Fourier algorithm to calculate the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment;

[0141] Based on the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment, calculating the effective value of the inter-phase voltage and the effective value of the inter-phase differential current at the current sampling moment;

[0142] For any two phases, determining the inter-phase inductance value of the any two phases based on the ratio of the effective value of the inter-phase voltage and the effective value of the inter-phase differential current of the any two phases at the current sampling moment.

[0143] Preferably, the inter-phase voltage and inter-phase inductance calculation unit 802 calculates the effective value of the inter-phase voltage and the effective value of the inter-phase differential current at the current sampling moment based on the three-phase voltage phasor values and three-phase differential current phasor values at the current sampling moment, including:

[0144] ,

[0145] ,

[0146] Among them, , and are respectively the effective values of the phase - to - phase voltages of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are respectively the effective values of the phase - to - phase differential currents of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are the three - phase voltage phasor values corresponding to the current sampling moment ; , and are the three - phase differential current phasor values corresponding to the current sampling moment .

[0147] Preferably, the phase - to - phase inductance change rate calculation unit 803 is configured to calculate the phase - to - phase inductance change rate of any two phases based on the phase - to - phase inductance.

[0148] Among them, the phase - to - phase inductance change rate of any two phases is calculated by the following method, including:

[0149] ,

[0150] Among them, , and are respectively the change rates of the phase - to - phase inductance values of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are respectively the phase - to - phase inductance values of the AB phase, BC phase, and AC phase corresponding to the current sampling moment ; , and are respectively the phase - to - phase inductance values of the AB phase, BC phase, and AC phase corresponding to the sampling moment n cycle fronts ago ; N is the number of sampling points per cycle.

[0151] Preferably, the fault determination unit 804 is configured to 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 satisfy a preset criterion; wherein, for any two phases, if the change rate of the phase-to-phase inductance value 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, it is determined that the preset criterion is satisfied.

[0152] Preferably, the protection unit 805 is configured to start turn-to-turn protection when the phase current amplitude of the reactor is greater than a first preset current value, and to actuate turn-to-turn protection when the duration of satisfying the preset criterion is greater than a first preset time;

[0153] Preferably, the protection unit 805 is further configured to:

[0154] Start turn-to-turn fault alarm when the phase current amplitude of the reactor is greater than a second preset current value, and issue a turn-to-turn fault alarm signal when the duration of satisfying the preset criterion is greater than a second preset time.

[0155] Preferably, the system further includes:

[0156] A short-circuit phase determination unit, configured 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 of is the turn-to-turn short-circuit phase;

[0157] Wherein, , and Are respectively the change rates of the phase-to-phase inductance values of any two phases, and φφ takes values of AB, BC, and AC; S is a fault phase identification coefficient.

[0158] The turn-to-turn fault protection system 800 of the embodiment of the present invention based on the change rate of the inductance value corresponds to the turn-to-turn fault protection method 100 of another embodiment of the present invention based on the change rate of the inductance value, and will not be elaborated here.

[0159] On the other hand of the present invention, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of any one of the turn-to-turn fault protection methods of a reactor based on the change rate of the inductance value are implemented.

[0160] On the other hand of the present invention, the present invention provides an electronic device, including:

[0161] The above-mentioned computer-readable storage medium; and

[0162] One or more processors for executing the program in the computer-readable storage medium.

[0163] The present invention has been described with reference to a few embodiments. However, as is well known to those skilled in the art, other embodiments equivalent to those disclosed above of the present invention equally fall within the scope of the present invention as defined by the appended patent claims.

[0164] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless otherwise explicitly defined therein. All references to "a / the [device, component, etc.]" are to be interpreted openly as at least one instance of the device, component, etc., unless otherwise explicitly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless explicitly stated.

[0165] Those skilled in the art will appreciate that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, 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.) having computer-usable program code embodied therein.

[0166] The present invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block in the flowchart illustrations and / or block diagrams, and combinations of flows and / or blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device create means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or combinations of blocks.

[0167] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means that implement the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or combinations of blocks.

[0168] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the steps of the process Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps for the functions specified in one block or a plurality of blocks.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific embodiments of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope 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 value; 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; 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 interphase inductance change rate of 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 effective value of the interphase voltage and the effective value of the interphase differential current 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 phase-to-phase inductance change rate 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 interphase inductance change rates of any two phases respectively, and 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 value; 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, 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 interphase inductance change rate of 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 effective value of the interphase voltage and the effective value of the interphase differential current 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 phase-to-phase inductance change rate 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 interphase inductance change rates of any two phases respectively, and 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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