A control method and device of a three-phase surge arrester and a medium

Abstract

This invention discloses a control method, device, and medium for a three-phase surge arrester. The method includes: performing a difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain a phase difference set; calculating the capacitive current of the three-phase surge arrester based on the amplitude of the three-phase fundamental current and the phase difference set; calculating the three-phase resistive fundamental current using the lead-lag relationship in the phase difference set based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current; and correcting the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current. This invention proposes a control method, device, and medium for a three-phase surge arrester. By calculating the three-phase resistive fundamental current using acquired data information and then using this value to correct the actual three-phase resistive fundamental current of the three-phase surge arrester, it can solve the problem of not being able to easily and effectively eliminate interference caused by inter-phase coupling capacitance during live testing of the surge arrester.

Description

Technical Field

[0001] This invention relates to the field of electrical measurement technology, and in particular to a control method, device and medium for a three-phase surge arrester. Background Technology

[0002] Lightning is an atmospheric discharge phenomenon that generates impulse voltages of tens of thousands to hundreds of thousands of volts and discharge currents of tens to hundreds of thousands of amperes. It can cause injury or death to people and livestock, destruction or burning of buildings, and significant damage to electrical equipment and power systems. Therefore, the application of surge arresters is of great importance. Surge arresters are an important device frequently used to protect communication cables from lightning damage. They can release lightning or, simultaneously, the energy of power system overvoltages, protecting electrical equipment from transient overvoltage hazards, and can also interrupt follow current to prevent system grounding short circuits. During live-line testing of surge arresters, the accuracy of the test may be reduced due to the influence of interphase coupling capacitance. Existing methods often employ phase compensation and three-phase current vector synthesis to eliminate interference and mitigate the effects of interphase coupling capacitance.

[0003] For eliminating the influence of interphase coupling capacitance, existing methods have low accuracy when using phase compensation for correction. The method of synthesizing three-phase current vectors to eliminate interference requires calculating and saving the capacitance current when the surge arrester is initially installed and the three-phase operation is in good condition. This value is then used for phase correction in subsequent measurements. Historical data needs to be retrieved after each measurement, which is labor-intensive, cumbersome, and requires high equipment operating conditions. It cannot easily achieve the goal of eliminating the influence of interphase coupling capacitance. Summary of the Invention

[0004] This invention provides a control method, device, and medium for a three-phase surge arrester to solve the problem that interference caused by inter-phase coupling capacitance cannot be easily and effectively eliminated when the surge arrester is subjected to live testing.

[0005] To address the above problems, this invention provides a control method for a three-phase surge arrester, comprising:

[0006] Obtain the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental current in the system containing the three-phase surge arrester;

[0007] The phase difference between the three-phase fundamental component phase and the three-phase current phase is calculated to obtain the phase difference set between the three-phase fundamental current and the reference voltage.

[0008] Based on the amplitude of the three-phase fundamental current and the phase difference set, the capacitive current of the three-phase surge arrester is calculated using the coupling relationship between the three phases and the rise and fall relationship of the current amplitude in the three-phase surge arrester.

[0009] Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the lead-lag relationship in the phase difference set.

[0010] The actual three-phase resistive fundamental current of the three-phase surge arrester is corrected using the three-phase resistive fundamental current.

[0011] This invention calculates the three-phase resistive fundamental current using acquired data, and then uses this value to correct the actual three-phase resistive fundamental current of a three-phase surge arrester, thereby eliminating interphase coupling capacitance interference in the arrester. Specifically, the coupling relationship and current amplitude fluctuations between the three phases in the three-phase surge arrester reflect the interphase coupling between phase B and phases A and C, leading to a decrease in the overall capacitive current of phases A and C relative to the capacitive current, and the relationship between various parameters. Therefore, the capacitive current can be calculated from this. Furthermore, the phase difference concentration and lag relationship reflect the changes after mutual influence between phases A, B, and C, thus eliminating the influence of coupling on the resistive current and quickly calculating the three-phase resistive fundamental current to correct the actual three-phase resistive fundamental current.

[0012] Compared to existing technologies, this invention utilizes the relationship between the three phases in a three-phase surge arrester to calculate the three-phase resistive fundamental current using a small amount of data. This corrects the actual three-phase resistive fundamental current of the three-phase surge arrester, thereby eliminating the interference of the coupling part on the resistive current. This method does not require specific operating conditions of the three phases in the three-phase surge arrester, and it involves less workload, is easy to operate, and has high accuracy. Therefore, it can solve the problem of not being able to easily and effectively eliminate the interference caused by inter-phase coupling capacitance when the surge arrester is being tested under energized conditions.

[0013] As a preferred embodiment, based on the amplitude of the three-phase fundamental current and the phase difference set, the capacitive current of the three-phase surge arrester is calculated using the coupling relationship and current amplitude rise / fall relationship between the three phases in the three-phase surge arrester, specifically as follows:

[0014] Based on the phase difference of phase A and phase difference of phase B in the phase difference set, and the current amplitude of phase A and phase B in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester is calculated by the first preset formula.

[0015] Alternatively, based on the phase difference of phase B and phase difference of phase C in the phase difference set, and the phase current amplitude of phase B and phase current amplitude of phase C in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester can be calculated by the second preset formula.

[0016] The first preset formula and the second preset formula are established based on the coupling relationship and the current amplitude rise and fall relationship between the three phases of the three-phase surge arrester.

[0017] This preferred solution provides two methods for obtaining the capacitive current of a three-phase surge arrester. Since the first and second preset formulas are established based on the coupling relationship and current amplitude rise and fall relationship between the three phases in the three-phase surge arrester, they can reflect the reduction of the overall capacitive current of phase A and phase C relative to the capacitive current caused by the phase-to-phase coupling of phase B to phase A and phase C in the three-phase surge arrester, and reflect the relationship between various parameters. Therefore, by using the first or second preset formula, the capacitive current can be calculated quickly.

[0018] As a preferred embodiment, the three-phase resistive fundamental current is calculated based on the amplitude of the three-phase fundamental total current, the phase difference set, and the capacitive current, using the lead-lag relationship within the phase difference set, specifically as follows:

[0019] Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset formulas.

[0020] The third, fourth, and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B, and phase C in the phase difference set.

[0021] In this preferred scheme, by comparing the magnitudes of phases A, B, and C in the phase difference concentration, the magnitude of each phase difference can be obtained, reflecting the degree of lead or lag of each phase, that is, the interference situation of the fundamental current of each phase. Therefore, the third, fourth, and fifth preset formulas established on this basis can reflect and eliminate the mutual influence between the currents affected by each phase fundamental current, and restore the three-phase resistive fundamental current.

[0022] As a preferred option, the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental total current of the system containing the three-phase surge arrester are obtained, specifically:

[0023] When the three-phase surge arrester is subjected to a live test, the three-phase voltage waveform of the three-phase surge arrester is recorded within a preset time. The three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental full current amplitude are obtained from the three-phase voltage waveform.

[0024] This preferred solution provides a method for obtaining the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental current. The three-phase voltage waveform of the three-phase surge arrester is recorded. Since the waveform is a sine wave, the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental current can be quickly calculated based on the data information in the figure.

[0025] As a preferred embodiment, the first preset formula and the second preset formula are specifically as follows:

[0026] The first preset formula is:

[0027]

[0028] The second preset formula is:

[0029]

[0030] in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. Let be the capacitive current of the three-phase surge arrester to be solved.

[0031] In this preferred embodiment, since the angle between the capacitive components of the A-phase, B-phase, and C-phase current amplitudes in the three-phase fundamental total current amplitude is 60°, the coupled current is in the opposite direction to the original capacitive current. Therefore, the phase-to-phase coupling of B-phase to A and C-phases will result in a 0.5% reduction in the overall capacitive current of A and C-phases. Therefore, the first and second preset expressions can be established from this.

[0032] As a preferred embodiment, the third, fourth, and fifth preset formulas are specifically as follows:

[0033] The third preset formula is:

[0034]

[0035] The fourth preset formula is:

[0036]

[0037] The fifth preset formula is:

[0038]

[0039] in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. , and Let be the three-phase resistive fundamental current to be solved.

[0040] In this preferred scheme, based on the magnitudes of phase differences A, B, and C, it can be known that phase A exhibits a leading condition, while phase C exhibits a lagging condition. Phase B, being affected by both phases A and C, does not exhibit either a leading or lagging condition. Therefore, the third and fifth preset formulas can eliminate the influence of the coupling part on the resistive current, restore the resistive fundamental currents of phases A and C, and obtain the standard value of the resistive fundamental current of phase B, preventing other fluctuations in the resistive fundamental current of phase B. Thus, the third, fourth, and fifth preset formulas established on this basis can reflect and eliminate the mutual influence between the currents affected by each phase's fundamental current, restoring the three-phase resistive fundamental current.

[0041] The present invention also provides a control device for a three-phase surge arrester, including a data acquisition module, a first calculation module, a second calculation module, a third calculation module and a current correction module;

[0042] The data acquisition module is used to acquire the three-phase fundamental component phase, three-phase current phase, and three-phase fundamental total current amplitude of the system where the three-phase surge arrester is located.

[0043] The first calculation module is used to perform a difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain the phase difference set between the three-phase fundamental current and the reference voltage;

[0044] The second calculation module is used to calculate the capacitive current of the three-phase surge arrester based on the amplitude of the three-phase fundamental current and the phase difference set, using the coupling relationship between the three phases and the current amplitude rise and fall relationship in the three-phase surge arrester.

[0045] The third calculation module is used to calculate the three-phase resistive fundamental current based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, using the lead-lag relationship in the phase difference set.

[0046] The current correction module is used to correct the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current.

[0047] As a preferred embodiment, the second calculation module specifically comprises:

[0048] Based on the phase difference of phase A and phase difference of phase B in the phase difference set, and the current amplitude of phase A and phase B in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester is calculated by the first preset formula.

[0049] Alternatively, based on the phase difference of phase B and phase difference of phase C in the phase difference set, and the phase current amplitude of phase B and phase current amplitude of phase C in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester can be calculated by the second preset formula.

[0050] The first preset formula and the second preset formula are established based on the coupling relationship and the current amplitude rise and fall relationship between the three phases of the three-phase surge arrester.

[0051] As a preferred embodiment, the third calculation module specifically comprises:

[0052] Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset formulas.

[0053] The third, fourth, and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B, and phase C in the phase difference set.

[0054] As a preferred embodiment, the data acquisition module specifically comprises:

[0055] When the three-phase surge arrester is subjected to a live test, the three-phase voltage waveform of the three-phase surge arrester is recorded within a preset time. The three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental full current amplitude are obtained from the three-phase voltage waveform.

[0056] As a preferred embodiment, the first preset formula and the second preset formula are specifically as follows:

[0057] The first preset formula is:

[0058]

[0059] The second preset formula is:

[0060]

[0061] in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. Let be the capacitive current of the three-phase surge arrester to be solved.

[0062] As a preferred embodiment, the third, fourth, and fifth preset formulas are specifically as follows:

[0063] The third preset formula is:

[0064]

[0065] The fourth preset formula is:

[0066]

[0067] The fifth preset formula is:

[0068]

[0069] in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. , and Let be the three-phase resistive fundamental current to be solved.

[0070] The present invention also provides a storage medium storing a computer program, which is called and executed by a computer to implement the control method of a three-phase surge arrester as described above. Attached Figure Description

[0071] Figure 1 This is a flowchart illustrating a control method for a three-phase surge arrester provided in an embodiment of the present invention;

[0072] Figure 2 This is the equivalent circuit of the three-phase surge arrester operating state provided in the embodiment of the present invention;

[0073] Figure 3 This is a voltage-current relationship diagram provided in an embodiment of the present invention;

[0074] Figure 4This is a schematic diagram of the structure of a control device for a three-phase surge arrester provided in an embodiment of the present invention. Detailed Implementation

[0075] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0076] In the description of this application, it should be understood that the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," "third," "fourth," and "fifth" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "several" means two or more.

[0077] The control method for a three-phase surge arrester described in this embodiment of the invention can be applied to situations where a three-phase surge arrester is being tested under energized conditions to obtain the fundamental resistive current. It can eliminate the influence of the coupling capacitor current and obtain the actual fundamental resistive current.

[0078] Example 1:

[0079] Please see Figure 1 The present invention provides a control method for a three-phase surge arrester, including steps S1 to S5, and the specific implementation steps are as follows:

[0080] S1. Obtain the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental current in the system where the three-phase surge arrester is located.

[0081] Step S1 in this embodiment of the invention specifically includes:

[0082] During the live-line test of a three-phase surge arrester, the three-phase voltage waveforms of the arrester are recorded within a preset time. The phase of the three-phase fundamental component (φ) is then obtained from the three-phase voltage waveforms. A1 φ B1 φ C1 ), three-phase current phase (φ) A2 φ B2 φ C2 ) and the amplitude of the three-phase fundamental total current (I A I B I C The phases of the three-phase fundamental components and the three-phase currents are obtained by multiplying the time difference by the angular velocity.

[0083] This embodiment provides a method for obtaining the three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental total current amplitude. The three-phase voltage waveform of the three-phase surge arrester is recorded. Since the waveform is a sine wave, the three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental total current amplitude can be quickly calculated based on the data information in the figure.

[0084] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 2 , Figure 2 This is the equivalent circuit of the three-phase surge arrester operating state provided in the embodiment of the present invention. Figure 2 In surge arrester testing, the fundamental resistive current is the equivalent current characterizing the operating state of the surge arrester. The purpose of conducting live surge arrester testing is to obtain this current. It is necessary to simultaneously measure the voltage phase of the system in which the surge arrester is located and the fundamental total current flowing through the surge arrester's discharge counter. By comparing it with the reference voltage phase, the capacitive current in the fundamental total current can be removed, and the resistive current can be obtained to judge the state of the surge arrester. If the resistive current exceeds a certain value, the surge arrester is considered to have a defect and needs to be shut down for testing in a timely manner.

[0085] like Figure 2 As shown, taking phase A as an example, the arrester's status can be determined by removing the capacitive current caused by capacitor Ca and obtaining the resistive current caused by its adjustable resistor Ra. However, in actual operation, phase A of the arrester is simultaneously subjected to the voltage of phase B, forming a coupling capacitance component due to the equivalent capacitance C0, leading to abnormal calculation results. It is generally assumed that the coupling capacitance of each phase is the same (e.g., ...). Figure 2 As shown in the figure, there are a total of 4 C0s. Phase A and Phase C are only affected by the coupling capacitor of Phase B, while Phase B is affected by the coupling capacitors of Phase A and Phase C. The control method of the three-phase surge arrester provided in this embodiment is to remove the influence of the coupling capacitor current and thus obtain its actual fundamental resistive current.

[0086] S2. Perform a difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain the phase difference set between the three-phase fundamental current and the reference voltage.

[0087] Step S2 in this embodiment of the invention is specifically as follows:

[0088] For the phase of the three-phase fundamental component (φ) A1 φ B1 φ C1 ) and three-phase current phase (φ) A2 φ B2 φ C2 Perform interpolation to obtain the phase difference set (θ) between the three-phase fundamental current and the reference voltage. A θ B θ C );

[0089] The specific calculation process is as follows:

[0090] θ A= φ A1- φ A2 ;

[0091] θ B= φ B1- φ B2 ;

[0092] θ C= φ C1- φ C2

[0093] S3. Based on the amplitude and phase difference set of the three-phase fundamental current, the capacitive current of the three-phase surge arrester is calculated by utilizing the coupling relationship between the three phases and the rise and fall relationship of the current amplitude in the three-phase surge arrester.

[0094] Step S3 in this embodiment of the invention is specifically as follows:

[0095] Based on the phase difference between phase A and phase B in the phase difference set, and the amplitudes of phase A and phase B currents in the total amplitude of the three-phase fundamental current, the capacitive current I caused by the interphase coupling capacitance C0 in the three-phase surge arrester is calculated using the first preset formula. C0 ;

[0096] Alternatively, based on the phase difference between phase B and phase C in the phase difference set, and the amplitudes of phase B and phase C in the total amplitude of the three-phase fundamental current, the capacitive current I caused by the interphase coupling capacitance C0 in the three-phase surge arrester can be calculated using the second preset formula. C0 ;

[0097] Among them, the first and second preset formulas are established based on the coupling relationship between the three phases of electricity and the rise and fall relationship of the current amplitude in the three-phase surge arrester.

[0098] The first preset formula is:

[0099]

[0100] The second preset formula is:

[0101]

[0102] in, , and These represent the amplitudes of phase A, phase B, and phase C currents, respectively, within the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C, respectively, within the phase difference set. Let be the capacitive current of the three-phase surge arrester to be solved.

[0103] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 3 , Figure 3 This is a voltage-current relationship diagram provided in an embodiment of the present invention. The diagram is based on the phase difference set (θ) between the three-phase fundamental current and the reference voltage. A θ B θ C This is a drawing that shows the amplitude of the three-phase fundamental current. , ), phase difference set (θ) A θ B θ C ), capacitor current amplitude The relationship between voltage and phase A. In the diagram, the horizontal axis represents the voltages of phases A, B, and C (the three-phase voltages are equal), and the vertical axis represents the amplitude of the three-phase fundamental current. , The total current synthesized.

[0104] The control method for a three-phase surge arrester described in this embodiment utilizes the characteristic that the capacitive current of the surge arrester does not change much under different operating conditions. It assumes that each capacitive current remains constant, therefore the influence of the coupling capacitor current can be ignored. For example... Figure 3 As shown, θ A Angle less than θ B This indicates that the capacitance current amplitude Under the influence of this, the phase of phase A leads that of phase B. Similarly, θ C Angle greater than θ B This indicates that the phase of phase C lags behind that of phase B. This is because the capacitive components of phases A, B, and C are at a 60° angle, and the coupled current... Since the direction of the capacitive current is opposite to that of the original phase, the phase-to-phase coupling of phase B to phases A and C results in a 0.5% reduction in the overall capacitive current of phases A and C. The amplitude can be obtained by subtracting the phase coupling capacitor current. .

[0105] This embodiment provides two methods for obtaining the capacitive current of a three-phase surge arrester. Since the first and second preset formulas are established based on the coupling relationship and current amplitude rise and fall relationship between the three phases in the three-phase surge arrester, they can reflect the reduction of the overall capacitive current of phase A and phase C relative to the capacitive current caused by the phase-to-phase coupling of phase B to phase A and phase C in the three-phase surge arrester, and reflect the relationship between various parameters. Therefore, by using the first or second preset formula, the capacitive current of the three-phase surge arrester can be calculated quickly.

[0106] S4. Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the lead-lag relationship in the phase difference set.

[0107] Step S4 of this embodiment of the invention is specifically as follows:

[0108] Based on the amplitude of the three-phase fundamental current ( , ), phase difference set (θ) A θ B θ C ) and capacitive current The three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset equations. , );

[0109] Among them, the third, fourth and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B and phase C in the phase difference set.

[0110] like Figure 3 As shown, due to the capacitance current amplitude Under the influence of θ A <θ B <θ C The phase of phase A is ahead of phase B, causing the resistive fundamental current of phase A to be larger than that of phase B. Therefore, the purpose of establishing the third preset formula is to eliminate the capacitance current amplitude based on the relationship between currents. The effect on the resistive fundamental current of phase A is to reduce the resistive fundamental current of phase A and restore the original resistive fundamental current of phase A.

[0111] Similarly, due to the amplitude of the capacitor current Under the influence of this, the phase of phase C lags behind that of phase B, resulting in a smaller resistive fundamental current in phase C compared to that in phase B. Therefore, the purpose of establishing the third preset formula is to eliminate the amplitude of the capacitor current based on the relationship between the currents. The effect on the C-phase resistive fundamental current is to increase the C-phase resistive fundamental current and restore the original C-phase resistive fundamental current.

[0112] It should be noted that since phase B is affected by the coupling capacitance of both phase A and phase C, it will not result in phase B not being either leading or lagging. Therefore, the standard resistive fundamental current of phase B can be directly obtained.

[0113] The third preset formula is:

[0114]

[0115] The fourth preset formula is:

[0116]

[0117] The fifth preset formula is:

[0118]

[0119] in, , and These represent the amplitudes of phase A, phase B, and phase C currents, respectively, within the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C, respectively, within the phase difference set. , and Let be the three-phase resistive fundamental current to be solved.

[0120] In this embodiment, by comparing the magnitudes of phases A, B, and C in the phase difference concentration, the magnitude of each phase difference can be obtained, reflecting the degree of lead or lag of each phase, that is, the interference situation of the fundamental current of each phase. Therefore, the third, fourth, and fifth preset formulas established on this basis can reflect and eliminate the mutual influence between the currents affected by each phase fundamental current, and restore the three-phase resistive fundamental current.

[0121] S5. Correct the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current.

[0122] Step S5 of this embodiment of the invention is specifically as follows:

[0123] Using three-phase resistive fundamental current ( , Correct the actual three-phase resistive fundamental current of the three-phase surge arrester.

[0124] Overall, the embodiments of the present invention have the following beneficial effects:

[0125] This embodiment utilizes the relationship between the three phases in a three-phase surge arrester to calculate the three-phase resistive fundamental current using a small amount of data. This corrects the actual three-phase resistive fundamental current of the three-phase surge arrester, thereby eliminating the interference of the coupling part on the resistive current. This method does not require specific operating conditions of the three phases in the three-phase surge arrester and has the advantages of low workload, simple operation, and high accuracy.

[0126] Among them, due to the coupling relationship and current amplitude rise and fall relationship between the three phases in the three-phase surge arrester, it can reflect the reduction of the overall capacitive current of phase A and phase C caused by the phase-to-phase coupling of phase B in the three-phase surge arrester to phase A and phase C, and the relationship between various parameters. Therefore, the capacitive current can be calculated from this. Due to the lead-lag relationship of the concentrated phase difference, it can reflect the changes after phase A, phase B and phase C are affected by each other. Therefore, the influence of the coupling part on the resistive current can be eliminated, and the three-phase resistive fundamental current can be quickly calculated to correct the actual three-phase resistive fundamental current.

[0127] Example 2:

[0128] Please see Figure 4 The embodiments of the present invention provide a control device for a three-phase surge arrester, including a data acquisition module 10, a first calculation module 20, a second calculation module 30, a third calculation module 40, and a current correction module 50;

[0129] Among them, the data acquisition module 10 is used to acquire the three-phase fundamental component phase, three-phase current phase and three-phase fundamental full current amplitude of the system where the three-phase surge arrester is located;

[0130] The first calculation module 20 is used to perform difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain the phase difference set between the three-phase fundamental current and the reference voltage.

[0131] The second calculation module 30 is used to calculate the capacitive current of the three-phase surge arrester based on the amplitude and phase difference set of the three-phase fundamental current, and by utilizing the coupling relationship between the three phases and the rise and fall relationship of the current amplitude in the three-phase surge arrester.

[0132] The third calculation module 40 is used to calculate the three-phase resistive fundamental current based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, using the lead-lag relationship in the phase difference set.

[0133] The current correction module 50 is used to correct the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current.

[0134] In one embodiment, the data acquisition module 10 specifically comprises:

[0135] During the live-line test of a three-phase surge arrester, the three-phase voltage waveforms of the arrester are recorded within a preset time. The phase of the three-phase fundamental component (φ) is then obtained from the three-phase voltage waveforms. A1 φ B1 φ C1 ), three-phase current phase (φ) A2 φ B2 φ C2 ) and the amplitude of the three-phase fundamental total current (I A I B I C The phases of the three-phase fundamental components and the three-phase currents are obtained by multiplying the time difference by the angular velocity.

[0136] This embodiment provides a method for obtaining the three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental total current amplitude. The three-phase voltage waveform of the three-phase surge arrester is recorded. Since the waveform is a sine wave, the three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental total current amplitude can be quickly calculated based on the data information in the figure.

[0137] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 2 , Figure 2 This is the equivalent circuit of the three-phase surge arrester operating state provided in the embodiment of the present invention. Figure 2 In surge arrester testing, the fundamental resistive current is the equivalent current characterizing the operating state of the surge arrester. The purpose of conducting live surge arrester testing is to obtain this current. It is necessary to simultaneously measure the voltage phase of the system in which the surge arrester is located and the fundamental total current flowing through the surge arrester's discharge counter. By comparing it with the reference voltage phase, the capacitive current in the fundamental total current can be removed, and the resistive current can be obtained to judge the state of the surge arrester. If the resistive current exceeds a certain value, the surge arrester is considered to have a defect and needs to be shut down for testing in a timely manner.

[0138] like Figure 2 As shown, taking phase A as an example, the arrester's status can be determined by removing the capacitive current caused by capacitor Ca and obtaining the resistive current caused by its adjustable resistor Ra. However, in actual operation, phase A of the arrester is simultaneously subjected to the voltage of phase B, forming a coupling capacitance component due to the equivalent capacitance C0, leading to abnormal calculation results. It is generally assumed that the coupling capacitance of each phase is the same (e.g., ...). Figure 2 As shown in the figure, there are a total of 4 C0s. Phase A and Phase C are only affected by the coupling capacitor of Phase B, while Phase B is affected by the coupling capacitors of Phase A and Phase C. The control device of the three-phase surge arrester provided in this embodiment is to remove the influence of the coupling capacitor current and thus obtain its actual fundamental resistive current.

[0139] In one embodiment, the first computing module 20 specifically comprises:

[0140] For the phase of the three-phase fundamental component (φ) A1 φ B1 φ C1 ) and three-phase current phase (φ) A2 φ B2 φ C2 Perform interpolation to obtain the phase difference set (θ) between the three-phase fundamental current and the reference voltage. A θ B θ C );

[0141] The specific calculation process is as follows:

[0142] θ A= φ A1- φ A2 ;

[0143] θ B= φ B1- φ B2 ;

[0144] θ C= φ C1- φ C2

[0145] In one embodiment, the second computing module 30 specifically comprises:

[0146] Based on the phase difference between phase A and phase B in the phase difference set, and the amplitudes of phase A and phase B currents in the total amplitude of the three-phase fundamental current, the capacitive current I caused by the interphase coupling capacitance C0 in the three-phase surge arrester is calculated using the first preset formula. C0 ;

[0147] Alternatively, based on the phase difference between phase B and phase C in the phase difference set, and the amplitudes of phase B and phase C in the total amplitude of the three-phase fundamental current, the capacitive current I caused by the interphase coupling capacitance C0 in the three-phase surge arrester can be calculated using the second preset formula. C0 ;

[0148] Among them, the first and second preset formulas are established based on the coupling relationship between the three phases of electricity and the rise and fall relationship of the current amplitude in the three-phase surge arrester.

[0149] The first preset formula is:

[0150]

[0151] The second preset formula is:

[0152]

[0153] in, , and These represent the amplitudes of phase A, phase B, and phase C currents, respectively, within the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C, respectively, within the phase difference set. Let be the capacitive current of the three-phase surge arrester to be solved.

[0154] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 3 , Figure 3 This is a voltage-current relationship diagram provided in an embodiment of the present invention. The diagram is based on the phase difference set (θ) between the three-phase fundamental current and the reference voltage. A θ B θ C This is a drawing that shows the amplitude of the three-phase fundamental current. , ), phase difference set (θ) A θ B θ C ), capacitor current amplitude The relationship between voltage and phase A. In the diagram, the horizontal axis represents the voltages of phases A, B, and C (the three-phase voltages are equal), and the vertical axis represents the amplitude of the three-phase fundamental current. , The total current synthesized.

[0155] The control device for a three-phase surge arrester described in this embodiment utilizes the characteristic that the capacitive current of the surge arrester itself does not change much under different operating conditions. It is assumed that each capacitive current remains constant, therefore the influence of the coupling capacitor current can be ignored. For example... Figure 3 As shown, θ A Angle less than θ B This indicates that the capacitance current amplitude Under the influence of this, the phase of phase A leads that of phase B. Similarly, θ C Angle greater than θ B This indicates that the phase of phase C lags behind that of phase B. This is because the capacitive components of phases A, B, and C are at a 60° angle, and the coupled current... Since the direction of the capacitive current is opposite to that of the original phase, the phase-to-phase coupling of phase B to phases A and C results in a 0.5% reduction in the overall capacitive current of phases A and C. The amplitude can be obtained by subtracting the phase coupling capacitor current. .

[0156] This embodiment provides two methods for obtaining the capacitive current of a three-phase surge arrester. Since the first and second preset formulas are established based on the coupling relationship and current amplitude rise and fall relationship between the three phases in the three-phase surge arrester, they can reflect the reduction of the overall capacitive current of phase A and phase C relative to the capacitive current caused by the phase-to-phase coupling of phase B to phase A and phase C in the three-phase surge arrester, and reflect the relationship between various parameters. Therefore, by using the first or second preset formula, the capacitive current of the three-phase surge arrester can be calculated quickly.

[0157] In one embodiment, the third calculation module 40 specifically comprises:

[0158] Based on the amplitude of the three-phase fundamental current ( , ), phase difference set (θ) A θ B θ C ) and capacitive current The three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset equations. , );

[0159] Among them, the third, fourth and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B and phase C in the phase difference set.

[0160] like Figure 3 As shown, due to the capacitance current amplitude Under the influence of θ A <θ B <θ C The phase of phase A is ahead of phase B, causing the resistive fundamental current of phase A to be larger than that of phase B. Therefore, the purpose of establishing the third preset formula is to eliminate the capacitance current amplitude based on the relationship between currents. The effect on the resistive fundamental current of phase A is to reduce the resistive fundamental current of phase A and restore the original resistive fundamental current of phase A.

[0161] Similarly, due to the amplitude of the capacitor current Under the influence of this, the phase of phase C lags behind that of phase B, resulting in a smaller resistive fundamental current in phase C compared to that in phase B. Therefore, the purpose of establishing the third preset formula is to eliminate the amplitude of the capacitor current based on the relationship between the currents. The effect on the C-phase resistive fundamental current is to increase the C-phase resistive fundamental current and restore the original C-phase resistive fundamental current.

[0162] It should be noted that since phase B is affected by the coupling capacitance of both phase A and phase C, it will not result in phase B not being either leading or lagging. Therefore, the standard resistive fundamental current of phase B can be directly obtained.

[0163] The third preset formula is:

[0164]

[0165] The fourth preset formula is:

[0166]

[0167] The fifth preset formula is:

[0168]

[0169] in, , and These represent the amplitudes of phase A, phase B, and phase C currents, respectively, within the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C, respectively, within the phase difference set. , and Let be the three-phase resistive fundamental current to be solved.

[0170] In this embodiment, by comparing the magnitudes of phases A, B, and C in the phase difference concentration, the magnitude of each phase difference can be obtained, reflecting the degree of lead or lag of each phase, that is, the interference situation of the fundamental current of each phase. Therefore, the third, fourth, and fifth preset formulas established on this basis can reflect and eliminate the mutual influence between the currents affected by each phase fundamental current, and restore the three-phase resistive fundamental current.

[0171] In one embodiment, the current correction module 50 specifically comprises:

[0172] Using three-phase resistive fundamental current ( , Correct the actual three-phase resistive fundamental current of the three-phase surge arrester.

[0173] Overall, this device has the following beneficial effects:

[0174] This device utilizes the relationship between the three phases in a three-phase surge arrester to calculate the three-phase resistive fundamental current using a small amount of data. This corrects the actual three-phase resistive fundamental current of the three-phase surge arrester, thereby eliminating the interference of the coupling part on the resistive current. This method does not require specific operating conditions of the three phases in the three-phase surge arrester and has the advantages of low workload, simple operation, and high accuracy.

[0175] Among them, due to the coupling relationship and current amplitude rise and fall relationship between the three phases in the three-phase surge arrester, it can reflect the reduction of the overall capacitive current of phase A and phase C caused by the phase-to-phase coupling of phase B in the three-phase surge arrester to phase A and phase C, and the relationship between various parameters. Therefore, the capacitive current can be calculated from this. Due to the lead-lag relationship of the concentrated phase difference, it can reflect the changes after phase A, phase B and phase C are affected by each other. Therefore, the influence of the coupling part on the resistive current can be eliminated, and the three-phase resistive fundamental current can be quickly calculated to correct the actual three-phase resistive fundamental current.

[0176] Example 3:

[0177] This invention provides a computer-readable storage medium including a stored computer program, wherein the computer program, when running, controls the device where the computer-readable storage medium is located to execute the control method for a three-phase surge arrester.

[0178] The control method for a three-phase surge arrester, if implemented as a software functional unit and used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0179] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A control method of a three-phase surge arrester, characterized by, include: Obtain the phase of the three-phase fundamental component, the phase of the three-phase current, and the amplitude of the three-phase fundamental current in the system containing the three-phase surge arrester; The phase difference between the three-phase fundamental component phase and the three-phase current phase is calculated to obtain the phase difference set between the three-phase fundamental current and the reference voltage. Based on the three-phase fundamental current amplitude and the phase difference set, the capacitive current of the three-phase surge arrester is calculated using the coupling relationship between the three phases and the current amplitude rise and fall relationship in the three-phase surge arrester. Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the lead-lag relationship in the phase difference set. The actual three-phase resistive fundamental current of the three-phase surge arrester is corrected using the three-phase resistive fundamental current.

2. The control method for a three-phase surge arrester as described in claim 1, characterized in that, Based on the amplitude of the three-phase fundamental current and the phase difference set, the capacitive current of the three-phase surge arrester is calculated using the coupling relationship between the three phases and the current amplitude rise and fall relationship. Specifically: Based on the phase difference of phase A and phase difference of phase B in the phase difference set, and the current amplitude of phase A and phase B in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester is calculated by the first preset formula. Alternatively, based on the phase difference between phase B and phase C in the phase difference set, and the phase current amplitudes of phase B and phase C in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester can be calculated using the second preset formula. The first preset formula and the second preset formula are established based on the coupling relationship and the current amplitude rise and fall relationship between the three phases of the three-phase surge arrester.

3. The control method for a three-phase surge arrester as described in claim 1, characterized in that, Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the lead-lag relationship within the phase difference set, specifically as follows: Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset formulas. The third, fourth, and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B, and phase C in the phase difference set.

4. The control method for a three-phase surge arrester as described in claim 1, characterized in that, To obtain the three-phase fundamental component phase, three-phase current phase, and three-phase fundamental total current amplitude of the system containing the three-phase surge arrester, specifically: When the three-phase surge arrester is subjected to a live test, the three-phase voltage waveform of the three-phase surge arrester is recorded within a preset time. The three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental full current amplitude are obtained from the three-phase voltage waveform.

5. The control method for a three-phase surge arrester as described in claim 2, characterized in that, The first preset formula and the second preset formula are specifically as follows: The first preset formula is: The second preset formula is: in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. Let be the capacitive current of the three-phase surge arrester to be solved.

6. The control method for a three-phase surge arrester as described in claim 3, characterized in that, The third, fourth, and fifth preset formulas are specifically as follows: The third preset formula is: The fourth preset formula is: The fifth preset formula is: in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. , and Let be the three-phase resistive fundamental current to be solved.

7. A control device for a three-phase surge arrester, characterized in that, It includes a data acquisition module, a first calculation module, a second calculation module, a third calculation module, and a current correction module; The data acquisition module is used to acquire the three-phase fundamental component phase, three-phase current phase, and three-phase fundamental total current amplitude of the system where the three-phase surge arrester is located. The first calculation module is used to perform a difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain the phase difference set between the three-phase fundamental current and the reference voltage; The second calculation module is used to calculate the capacitive current of the three-phase surge arrester based on the amplitude of the three-phase fundamental current and the phase difference set, using the coupling relationship between the three phases and the current amplitude rise and fall relationship in the three-phase surge arrester. The third calculation module is used to calculate the three-phase resistive fundamental current based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, using the lead-lag relationship in the phase difference set. The current correction module is used to correct the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current.

8. The control device for a three-phase surge arrester as described in claim 7, characterized in that, The second calculation module is specifically as follows: Based on the phase difference of phase A and phase difference of phase B in the phase difference set, and the current amplitude of phase A and phase B in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester is calculated by the first preset formula. Alternatively, based on the phase difference between phase B and phase C in the phase difference set, and the phase current amplitudes of phase B and phase C in the three-phase fundamental current amplitude, the capacitive current of the three-phase surge arrester can be calculated using the second preset formula. The first preset formula and the second preset formula are established based on the coupling relationship and the current amplitude rise and fall relationship between the three phases of the three-phase surge arrester.

9. The control device for a three-phase surge arrester as described in claim 7, characterized in that, The third calculation module is specifically: Based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current, the three-phase resistive fundamental current is calculated using the third, fourth, and fifth preset formulas. The third, fourth, and fifth preset formulas are established based on the lead-lag relationship, which is obtained by comparing the magnitudes of phase A, phase B, and phase C in the phase difference set.

10. The control device for a three-phase surge arrester as described in claim 7, characterized in that, The data acquisition module is specifically: When the three-phase surge arrester is subjected to a live test, the three-phase voltage waveform of the three-phase surge arrester is recorded within a preset time. The three-phase fundamental component phase, the three-phase current phase, and the three-phase fundamental full current amplitude are obtained from the three-phase voltage waveform.

11. The control device for a three-phase surge arrester as described in claim 8, characterized in that, The first preset formula and the second preset formula are specifically as follows: The first preset formula is: The second preset formula is: in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. Let be the capacitive current of the three-phase surge arrester to be solved.

12. The control device for a three-phase surge arrester as described in claim 9, characterized in that, The third, fourth, and fifth preset formulas are specifically as follows: The third preset formula is: The fourth preset formula is: The fifth preset formula is: in, , and These are the amplitudes of phase A, phase B, and phase C currents, respectively, in the total amplitude of the three-phase fundamental current. , and These are the phase differences of phase A, phase B, and phase C in the phase difference set, respectively. , and Let be the three-phase resistive fundamental current to be solved.

13. A storage medium, characterized in that, The storage medium stores a computer program, which is called and executed by a computer to implement the control method of any one of the three-phase surge arresters as described in claims 1 to 6.

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