Fault phase determination method, control device and computer storage medium

Abstract

The present invention relates to a method for determining a fault phase, a control device and a computer storage medium, and the method comprises: S1, obtaining the operating parameters of the distribution network; S2, determining the ground current fluctuation of each phase according to the operating parameters of the distribution network; S3, respectively calculating the contour inclination coefficients corresponding to the ground current fluctuation of each phase, and obtaining three contour inclination coefficients corresponding to each phase one by one; S4, calculating the sum of the minimum value and the middle value of the three contour inclination coefficients, and obtaining the coefficient sum; S5, judging whether the maximum value of the three contour inclination coefficients is greater than the coefficient sum, and if so, judging that the phase corresponding to the maximum value is the fault phase. The present invention can accurately determine the fault phase, help to improve the arc extinguishing effect, and effectively prevent the voltage rise caused by arc extinguishing of non-fault phases.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution network control, and in particular to a fault phase determination method, a control device and a computer storage medium. Background Art

[0002] The probability of single-phase grounding fault in distribution network is high, generally accounting for more than 70% of the total faults in distribution network. Single-phase grounding fault can easily be converted into arc grounding, resulting in overvoltage, which in turn causes phase-to-phase short circuit, and may even cause the fault to expand, endangering personal safety and equipment safety. Therefore, arc extinguishing equipment is usually configured to eliminate the arc generated by the grounding fault to avoid the deterioration of the accident. However, in the related technology, due to the limitation of the existing method of determining the fault phase, the accuracy rate is low, resulting in no good arc extinguishing effect no matter what arc extinguishing method is used (such as current arc extinguishing method and voltage arc extinguishing method, etc.), and when the non-fault phase is extinguished, the voltage will rise, which may cause fluctuations in the output of the distribution network at the least, and may even cause equipment damage at the worst. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for determining a fault phase, a control device and a computer storage medium.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing a fault phase determination method, comprising:

[0005] S1. Obtaining distribution network operating parameters;

[0006] S2. Determine the ground current fluctuation of each phase according to the operating parameters of the distribution network;

[0007] S3, respectively calculating the profile inclination coefficients corresponding to the ground current fluctuation amount of each phase, and obtaining three profile inclination coefficients corresponding to each phase;

[0008] S4, calculating the sum of the minimum value and the middle value of the three profile inclination coefficients to obtain a coefficient sum;

[0009] S5. Determine whether the maximum value among the three profile inclination coefficients is greater than the coefficient sum. If so, determine that the phase corresponding to the maximum value is a faulty phase.

[0010] Preferably, the distribution network operating parameters include three-phase voltage, angular frequency, fault initial phase angle, resonant angular frequency, three-phase to ground capacitance, three-phase to ground inductance and neutral point voltage;

[0011] The S2 includes:

[0012] S21, determining the capacitive current of each phase to ground according to the three-phase voltage and the three-phase capacitance to ground;

[0013] S22, determining the ground capacitance current fluctuation amount of each phase according to the initial phase angle of the fault and the ground capacitance current of each phase;

[0014] S23, determining the ground inductance current of each phase according to the three-phase voltage and the three-phase ground inductance;

[0015] S24, determining the fluctuation amount of the ground inductance current of each phase according to the initial phase angle of the fault, the resonant angular frequency and the ground inductance current of each phase;

[0016] S25, determining the ground fault current fluctuation of each phase according to the neutral point voltage and the three-phase ground capacitance;

[0017] S26. Determine the current fluctuation amount to ground of each phase according to the capacitance current fluctuation amount to ground, the inductance current fluctuation amount to ground and the fault current fluctuation amount to ground of each phase.

[0018] Preferably, in S22, the capacitance current fluctuation expression of each phase is: ; Among them, P represents the phase line, Indicates the capacitance current fluctuation of the P phase, represents the capacitive current of phase P to ground, represents the angular frequency, represents the initial phase angle of the fault;

[0019] In S24, the expression of the ground inductance current fluctuation of each phase is: ;in, Indicates the fluctuation of the P-phase inductance current to ground. represents the inductance current of the P phase to ground, represents the resonant angular frequency;

[0020] In S25, the fluctuation amount of the ground fault current of each phase is expressed as: ;in, Indicates the fluctuation of the ground fault current of phase P. Represents the capacitance of the P phase to ground, represents the neutral point voltage.

[0021] Preferably, in S26, the ground current fluctuation amount expression of each phase is: ;in, Indicates the current fluctuation of the P phase to ground.

[0022] Preferably, in S3, the profile inclination coefficient expression of each phase is:

[0023] ;

[0024] in, represents the profile inclination coefficient of the P phase, m represents the number of sampling points of the ground current fluctuation, i represents the sampling point number, represents the ground current fluctuation at the i-th sampling point, Represents the average value of m ground current fluctuations.

[0025] Preferably, the fault phase determination method further includes:

[0026] S6. Determine whether the voltage of the faulty phase is not greater than the calibration value. If so, the faulty phase is determined to be wrong, and return to S1.

[0027] Preferably, in said S6, it further includes:

[0028] Determining a calibration coefficient according to the distribution network operating parameters;

[0029] The calibration value is determined according to a preset voltage value and the calibration coefficient.

[0030] Preferably, in S6, the expression of the calibration coefficient is:

[0031] ; Wherein, che represents the calibration coefficient, represents the angular frequency, It represents the total three-phase capacitance to ground. Indicates the total three-phase inductance to ground;

[0032] The expression of the check value is: ,in, Indicates the preset voltage value.

[0033] The present invention also constructs a control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned fault phase determination method when executing the computer program.

[0034] The present invention also constructs a computer storage medium storing a computer program, which implements the steps of the above-mentioned fault phase determination method when running.

[0035] The implementation of the present invention has the following beneficial effects: it can accurately determine the fault phase, help improve the arc extinguishing effect, and effectively prevent the voltage rise caused by arc extinguishing of the non-fault phase, which plays a positive role in improving the output stability of the distribution network and protecting the distribution network equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1 is a program flow chart of a method for determining a fault phase in some embodiments of the present invention;

[0038] Figure 2 is a flowchart of step S2 in some embodiments of the present invention;

[0039] Figure 3 is a circuit structure block diagram of a control device in some embodiments of the present invention. DETAILED DESCRIPTION

[0040] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0041] It should be noted that the flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0042] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0043] The present invention provides a method for determining a fault phase, which can accurately determine the phase line where a ground fault occurs in a distribution network, and plays a positive role in improving the arc extinguishing effect. Figure 1 As shown, the fault phase determination method may include step S1, step S2, step S3, step S4 and step S5.

[0044] Step S1 includes: obtaining the working parameters of the distribution network. In order to ensure the reliable operation of the distribution network, the nuclear power plant or the power station will be equipped with a dedicated monitoring device to monitor the real-time working parameters of the distribution network, such as monitoring the three-phase voltage, three-phase current, period, angular frequency, resonant angular frequency (also called resonant angle vector), three-phase capacitance to ground, three-phase inductance to ground and neutral point voltage of the distribution network, so as to achieve the purpose of timely detection of faults by analyzing these working parameters, including ground faults, short circuit faults, abnormal voltage faults, etc. For example, the three-phase voltage, three-phase current, period, angular frequency and neutral point voltage of the power grid are monitored by a three-phase power monitor, and the three-phase capacitance and inductance tester of the power grid are monitored. When a fault occurs, the phase angle of the voltage or current at the time of the fault (such as a ground fault) is also recorded to obtain the initial phase angle of the fault. The resonant angular frequency can be calculated based on the three-phase capacitance to ground and the three-phase inductance to ground. It can be understood that this step can obtain the distribution network operating parameters by communicating with the existing monitoring equipment of the distribution network. Specifically, the distribution network operating parameters may include three-phase voltage, angular frequency, initial fault phase angle, resonant angular frequency, three-phase capacitance to ground, three-phase inductance to ground and neutral point voltage. It should be noted that the three-phase voltage includes the voltages corresponding to the A phase, B phase and C phase of the distribution network, the three-phase capacitance to ground includes the capacitance to ground corresponding to the A phase, B phase and C phase of the distribution network, and the three-phase inductance to ground includes the inductance to ground corresponding to the A phase, B phase and C phase of the distribution network.

[0045] Step S2 includes: determining the ground current fluctuation of each phase according to the working parameters of the distribution network. When a ground fault occurs in a phase of the distribution network, the ground current of the phase line where the ground fault occurs (referred to as the fault phase) will fluctuate significantly, and the role of this step is to calculate the ground current fluctuation of each phase based on the working parameters of the distribution network, in preparation for the subsequent positioning of the fault phase. It should be noted that since a ground fault will cause three-phase imbalance, even if the ground current of the phase line where the ground fault does not occur will fluctuate, it is impossible to accurately determine the fault phase by analyzing the ground current fluctuation of each phase alone.

[0046] In some embodiments, Figure 2 As shown, step S2 may include step S21, step S22, step S23, step S24, step S25 and step S26.

[0047] Step S21 includes: determining the ground capacitance current of each phase according to the three-phase voltage and the three-phase ground capacitance.

[0048] In some embodiments, the expression of the ground capacitance current of each phase can be: , where P represents the phase line (P can be A, B or C), represents the capacitive current of phase P to ground, represents the period of the distribution network (which can be calculated by the angular frequency of the distribution network), Represents the capacitance of the P phase to ground, Indicates the voltage of the P phase.

[0049] Because some monitoring devices have the function of monitoring three-phase capacitive current to ground, in other embodiments, step S21 may include: acquiring the capacitive current to ground of each phase by communicating with the monitoring device.

[0050] Step S22 includes: determining the ground capacitance current fluctuation amount of each phase according to the initial phase angle of the fault and the ground capacitance current of each phase.

[0051] In some embodiments, the expression of the capacitance current fluctuation of each phase can be: ,in, Indicates the capacitance current fluctuation of the P phase, represents the angular frequency of the distribution network, Indicates the initial fault phase angle of the distribution network.

[0052] Step S23 includes: determining the ground inductance current of each phase according to the three-phase voltage and the three-phase ground inductance.

[0053] In some embodiments, the expression of the ground inductance current of each phase can be: ,in, It represents the inductance current of P phase to ground.

[0054] Because some monitoring devices have the function of monitoring three-phase to ground capacitive currents, in other embodiments, step S23 may include: acquiring the to-ground inductive current of each phase by communicating with the monitoring device.

[0055] Step S24 includes: determining the fluctuation amount of the ground inductance current of each phase according to the initial phase angle of the fault, the resonant angular frequency and the ground inductance current of each phase.

[0056] In some embodiments, the expression of the ground inductance current fluctuation of each phase can be: ,in, Indicates the fluctuation of the P-phase inductance current to ground. Represents the resonant angular frequency.

[0057] Step S25 includes: determining the ground fault current fluctuation of each phase according to the neutral point voltage and the three-phase ground capacitance.

[0058] In some embodiments, the expression of the ground fault current fluctuation of each phase can be: ,in, Indicates the fluctuation of the ground fault current of phase P. Indicates the neutral point voltage.

[0059] Step S26 includes: determining the ground current fluctuation amount of each phase according to the ground capacitance current fluctuation amount, the ground inductance current fluctuation amount and the ground fault current fluctuation amount of each phase respectively.

[0060] In some embodiments, the expression of the ground current fluctuation of each phase can be: ,in, Indicates the fluctuation of the P-phase ground current. It can be understood that , and They correspond to the ground current fluctuations of phases A, B and C respectively.

[0061] Step S3 includes: calculating the profile inclination coefficients corresponding to the ground current fluctuation of each phase, and obtaining three profile inclination coefficients corresponding to each phase. In this step, the profile inclination coefficient can reflect the fluctuation amplitude of the ground current of the corresponding phase line. The larger the profile inclination coefficient, the larger the fluctuation amplitude of the ground current.

[0062] In some embodiments, the expression of the profile tilt coefficient of each phase can be: ,in, represents the profile inclination coefficient of the P phase, m represents the number of sampling points of the ground current fluctuation (m is a positive integer), i represents the sampling point number, represents the ground current fluctuation at the i-th sampling point, represents the average value of m ground current fluctuations. It can be understood that from the expression of ground current fluctuations, is a function of the current change over time, so the time value can be substituted to determine the corresponding Accordingly, m and the number of each sampling point can be determined in the following manner: the number of sampling points of the ground current fluctuation quantity is determined according to the preset sampling period and sampling frequency (m is equal to the product of the sampling period and the sampling frequency), and the sampling period is evenly divided into m time intervals; the starting time or the ending time of each time interval is determined as a sampling point to obtain m sampling points corresponding to the m time intervals one by one; the m sampling points are numbered from small to large according to the time size to obtain the sampling point number corresponding to each sampling point.

[0063] Step S4 includes: calculating the sum of the minimum value and the middle value of the three profile inclination coefficients to obtain the coefficient sum. It should be noted that the minimum value corresponds to the smallest profile inclination coefficient among the three profile inclination coefficients, the minimum value corresponds to the largest profile inclination coefficient among the three profile inclination coefficients, and the middle value corresponds to the profile inclination coefficients other than the maximum value and the minimum value among the three profile inclination coefficients.

[0064] Step S5 includes: judging whether the maximum value among the three profile inclination coefficients is greater than the coefficient sum, and if so, judging that the phase corresponding to the maximum value is the fault phase. When a ground fault occurs in a phase line, the current flowing into the ground increases sharply (i.e., the current to the ground increases sharply), so its profile inclination coefficient will increase significantly, and when the maximum value among the three profile inclination coefficients is greater than the coefficient sum, it can be inferred that the phase corresponding to the maximum value has a ground short circuit fault (i.e., the fault phase). On the contrary, when there is no ground fault in the distribution network, since the three phases are balanced and no current leaks into the ground, the three profile inclination coefficients are generally close to equal, so when the maximum value is not greater than the coefficient sum, it can be judged that there is no ground fault in the distribution network.

[0065] Considering that grid noise may affect the accuracy of determining the fault phase, in some embodiments, such as Figure 1 As shown, the fault phase determination method may further include step S6.

[0066] Step S6 includes: judging whether the voltage of the fault phase is not greater than the check value, if it is judged that the fault phase is wrong, and returning to S1, otherwise it is judged that the fault phase is correct, and outputting an arc extinguishing permission signal. The arc extinguishing permission signal includes the fault phase information, and the arc extinguishing device will execute the arc extinguishing procedure for the fault phase after receiving the arc extinguishing permission signal.

[0067] Furthermore, step S6 may also include: determining a calibration coefficient according to an operating parameter of the distribution network, and determining a calibration value according to a preset voltage value and the calibration coefficient.

[0068] The expression of the calibration coefficient can be: , where che represents the calibration coefficient, represents the angular frequency, It represents the total three-phase capacitance to ground. Represents the total three-phase inductance to ground. The expression of the calibration value can be: ,in, Indicates the preset voltage value, which can be customized by the staff.

[0069] The technical solution of the present invention first obtains the working parameters of the distribution network, then determines the ground current fluctuation of each phase according to the working parameters of the distribution network, and then calculates the contour inclination coefficients corresponding to the ground current fluctuation of each phase respectively, thereby obtaining three contour inclination coefficients, and then calculates the sum of the minimum value and the middle value of the three contour inclination coefficients (that is, the coefficient sum). When the maximum value of the three contour inclination coefficients is greater than the coefficient sum, the phase corresponding to the maximum value is determined as the fault phase. It has the advantage of high accuracy in determining the fault phase, helps to improve the arc extinguishing effect, and effectively prevents the voltage increase caused by arc extinguishing of non-fault phases, which plays a positive role in improving the output stability of the distribution network and protecting the distribution network equipment.

[0070] like Figure 3 As shown, the present invention also provides a control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the fault phase determination method provided in an embodiment of the present invention are implemented.

[0071] The present invention also provides a computer storage medium storing a computer program, which implements the steps of the fault phase determination method provided in the embodiment of the present invention when the computer program is executed.

[0072] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0073] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0074] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0075] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A method for determining a fault phase, characterized in that: include: S1. Obtaining distribution network operating parameters; S2. Determine the ground current fluctuation of each phase according to the operating parameters of the distribution network; S3, respectively calculating the profile inclination coefficients corresponding to the ground current fluctuation amount of each phase, and obtaining three profile inclination coefficients corresponding to each phase; S4, calculating the sum of the minimum value and the middle value of the three profile inclination coefficients to obtain a coefficient sum; S5, determining whether the maximum value among the three profile inclination coefficients is greater than the coefficient sum, and if so, determining that the phase corresponding to the maximum value is a fault phase; The expression of the profile tilt coefficient of each phase is: ； in, represents the profile inclination coefficient of the P phase, m represents the number of sampling points of the ground current fluctuation, i represents the sampling point number, represents the ground current fluctuation at the i-th sampling point, Represents the average value of m ground current fluctuations.

2. The method for determining a fault phase according to claim 1, characterized in that: The distribution network operating parameters include three-phase voltage, angular frequency, fault initial phase angle, resonant angular frequency, three-phase to ground capacitance, three-phase to ground inductance and neutral point voltage; The S2 includes: S21, determining the capacitive current of each phase to ground according to the three-phase voltage and the three-phase capacitance to ground; S22, determining the ground capacitance current fluctuation amount of each phase according to the initial phase angle of the fault and the ground capacitance current of each phase; S23, determining the ground inductance current of each phase according to the three-phase voltage and the three-phase ground inductance; S24, determining the fluctuation amount of the ground inductance current of each phase according to the initial phase angle of the fault, the resonant angular frequency and the ground inductance current of each phase; S25, determining the ground fault current fluctuation of each phase according to the neutral point voltage and the three-phase ground capacitance; S26. Determine the current fluctuation amount to ground of each phase according to the capacitance current fluctuation amount to ground, the inductance current fluctuation amount to ground and the fault current fluctuation amount to ground of each phase.

3. The method for determining a fault phase according to claim 2, characterized in that: In S22, the capacitance current fluctuation expression of each phase is: ; Among them, P represents the phase line, Indicates the capacitance current fluctuation of the P phase, represents the capacitive current of phase P to ground, represents the angular frequency, represents the initial phase angle of the fault; In S24, the expression of the ground inductance current fluctuation of each phase is: ;in, Indicates the fluctuation of the P-phase inductance current to ground. represents the inductance current of the P phase to ground, represents the resonant angular frequency; In S25, the fluctuation amount of the ground fault current of each phase is expressed as: ;in, Indicates the fluctuation of the ground fault current of phase P. Represents the capacitance of the P phase to ground, represents the neutral point voltage.

4. The method for determining a fault phase according to claim 3, characterized in that: In S26, the ground current fluctuation expression of each phase is: ;in, Indicates the current fluctuation of the P phase to ground.

5. The method for determining a fault phase according to any one of claims 2 to 4, characterized in that: Also includes: S6. Determine whether the voltage of the faulty phase is not greater than the calibration value. If so, the faulty phase is determined to be wrong, and return to S1.

6. The method for determining a fault phase according to claim 5, characterized in that: In the S6, it also includes: Determining a calibration coefficient according to the distribution network operating parameters; The calibration value is determined according to a preset voltage value and the calibration coefficient.

7. The method for determining a fault phase according to claim 6, characterized in that: In S6, the expression of the calibration coefficient is: ;in, che represents the calibration coefficient, represents the angular frequency, It represents the total three-phase capacitance to ground. Indicates the total three-phase inductance to ground; The expression of the check value is: ,in, Indicates the preset voltage value.

8. A control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the fault phase determination method according to any one of claims 1 to 7 are implemented.

9. A computer storage medium, characterized in that A computer program is stored, and when the computer program is executed, the steps of the fault phase determination method according to any one of claims 1 to 7 are implemented.

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