Power supply control method and system of power supply panel for secondary power distribution

Abstract

The invention relates to the technical field of power supply screen power supply automatic switching, in particular to a secondary power distribution power supply screen power supply control method and system, and the method comprises the steps: collecting the voltage data of each phase in the operation process of a power supply screen within a preset time period; extracting a fault phase and a to-be-analyzed phase by comparing the effective value of the voltage data of each phase in the preset time period with a preset threshold value, and if at least one fault phase exists, switching a power supply of the power supply screen; if only the to-be-analyzed phase exists, acquiring a periodic zero sequence of each phase by analyzing a zero sequence fault of a power supply of the power supply panel; and calculating the difference of the same position elements between the periodic zero point sequences of any two phases, obtaining the phase deviation between any two phases by combining the deviation between the difference and a preset standard difference, and controlling the power supply switching of the power supply panel. The invention aims to guarantee the stable operation of the power supply panel by improving the fault detection sensitivity of the power supply of the power supply panel.

Description

Technical Field

[0001] The present application relates to the technical field of automatic power switching of power panels, and in particular to a power control method and system for a power panel with secondary power distribution. Background Art

[0002] Secondary power distribution is the process of converting high-voltage power into low-voltage power and distributing it to end users in the power system. During the operation of the power panel of secondary power distribution, the power panel generally uses dual power supplies, including a main power supply and a backup power supply. When the main power supply is normal, the main power supply is used for power supply; when the main power supply fails, it automatically switches to the backup power supply for power supply. Before the automatic switching control of the power supply of the power panel is performed, it is usually necessary to monitor the operating status of the main power supply.

[0003] Traditional power supply operation status monitoring methods mainly monitor the power supply voltage by presetting voltage thresholds. However, in a multi-phase power supply, when a zero-sequence fault occurs, that is, the three-phase voltage is unbalanced, resulting in the phase sum of the three voltage phases not being zero, if the three-phase voltage imbalance is relatively mild, the voltage of each phase may still be within the normal threshold range, but at this time the multi-phase power supply already has a zero-sequence fault, making it difficult to detect the fault in a timely and accurate manner through voltage threshold monitoring, resulting in insensitive fault detection results. Summary of the invention

[0004] In view of the above, it is necessary to provide a power supply control method and system for a power supply panel of secondary power distribution. Compared with the traditional power supply control method for a power supply panel, the sensitivity of fault detection of the power supply panel is improved to ensure the stable operation of the power supply panel:

[0005] In a first aspect, an embodiment of the present application provides a power supply control method for a power supply panel of a secondary power distribution, the method comprising the following steps:

[0006] Collect voltage data of each phase of the power panel during operation within a preset time period;

[0007] By comparing the effective value of the voltage data of each phase within the preset time period with the preset threshold, the fault phase and the phase to be analyzed are extracted, and if there is at least one fault phase, the power supply of the power panel is switched;

[0008] If there is only a phase to be analyzed, the periodic zero point sequence of each phase is obtained by analyzing the zero-sequence fault of the power supply of the power panel;

[0009] Calculate the difference between the elements at the same position between the periodic zero point sequences of any two phases, and combine the deviation between the difference and the preset standard difference to obtain the phase deviation between the any two phases;

[0010] Based on the phase deviation, power switching of the power panel is controlled.

[0011] In one embodiment, the method for extracting the fault phase and the phase to be analyzed is:

[0012] The effective value is the root mean square value of all voltage data of each phase within the preset time period;

[0013] When the effective value of any phase is less than a preset first threshold, determining that any phase is a fault phase;

[0014] When the effective value of any phase is greater than or equal to the preset first threshold value and less than or equal to the preset second threshold value, it is determined that any phase is the phase to be analyzed.

[0015] In one embodiment, the process of acquiring the periodic zero point sequence is as follows:

[0016] Record the moment when the voltage data is 0 as the 0-value moment, and for any phase, arrange the order of all the 0-value moments in the preset neighboring time domain of each 0-value moment in all the acquisition moments from small to large to form a time series of each 0-value moment; calculate the mean of all elements in each time series;

[0017] For any time series and its adjacent previous time series, calculate the difference between each element in the any time series and the mean value of the previous time series;

[0018] By comparing the first preset value with the difference corresponding to each element in the any time series, the period zero point difference of each element in the any time series is obtained, and the element as the period zero point is extracted from the any time series according to the period zero point difference;

[0019] All periodic zero points of any phase are arranged in time sequence to form a periodic zero point sequence of any phase.

[0020] In one embodiment, the period zero point difference is the difference between the first preset value and the difference corresponding to each element in any time series.

[0021] In one embodiment, the periodic zero point is an element with the smallest periodic zero point difference in any time series.

[0022] In one embodiment, the calculation relationship of the phase deviation is:

[0023] Where, Pl A,B Indicates the phase deviation between phase A and phase B; M A,B Represents the minimum number of elements in the periodic zero sequence of phase A and phase B; Z A,x , Z B,xRespectively represent the xth element in the periodic zero point sequence of phase A and phase B; P represents the number of voltage data collected within a preset time length; n represents the number of AC cycles within the preset time length;

[0024] According to the calculation method of the phase deviation between phase A and phase B, the phase deviation between phase A and phase C and the phase deviation between phase B and phase C are calculated respectively.

[0025] In one embodiment, when the phase deviation between any two phases is less than a second preset value, the power supply of the power panel is not switched; otherwise, the power supply of the power panel is switched.

[0026] In one embodiment, before switching the power supply of the power panel, it is necessary to detect the startup status of the backup power supply and the distribution of the output voltage and frequency.

[0027] In one of the embodiments, after the power supply of the power supply panel is switched from the main power supply to the backup power supply, feedback control technology is used to correct the phase corresponding to the phase deviation greater than the second preset value based on the phase deviation greater than the second preset value. After the correction is completed, the power supply of the power supply panel is switched from the backup power supply to the main power supply.

[0028] In the second aspect, an embodiment of the present application also provides a power supply control system for a power supply panel of secondary power distribution, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, it implements the steps of any one of the above-mentioned power supply control methods for a power supply panel of secondary power distribution.

[0029] This application has at least the following beneficial effects:

[0030] According to the change characteristics of the voltage data of the faulty phase and the normal phase when the power supply of the power supply panel has a ground fault, the application judges whether the power supply panel has a ground fault by comparing the effective value of the voltage data of each phase within a preset time length with the preset threshold value. If a ground fault occurs, the power supply panel is switched from the main power supply to the backup power supply to ensure the stable operation of the power supply panel; further, by analyzing the time distribution of the voltage data being 0 and calculating the cycle zero point of each phase, it is possible to avoid using the zero point caused by voltage instability and environmental noise as the cycle zero point, thereby improving the accuracy of the subsequent calculation of the phase deviation between adjacent phases according to the cycle zero point, judging whether the phase deviation between adjacent phases exceeds the normal range, and if it exceeds, switching the power supply panel from the main power supply to the backup power supply to avoid using the main power supply for power supply when the phase difference of the main power supply is abnormal, resulting in affecting the stability of the output power. By analyzing the voltage data during the operation of the power supply panel, various faults of the power supply panel can be discovered in time, the sensitivity of fault detection of the power supply panel can be improved, and an accurate basis can be provided for the switching control of the power supply panel to ensure the stable operation of the power supply panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A flowchart of a power supply control method for a power supply panel of a secondary power distribution provided in one embodiment of the present application;

[0033] Figure 2 This is a schematic diagram of the star connection method;

[0034] Figure 3 This is the switching control flow chart of the power supply of the power panel. DETAILED DESCRIPTION

[0035] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" and the like is intended to present related concepts in a concrete manner.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the present application. The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be understood that, unless otherwise specified, " / " means or.

[0037] It should also be noted that the terms "first" and "second" in the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0038] The following is a detailed description of a specific scheme of a power supply control method and system for a secondary power distribution power supply panel provided by the present application in conjunction with the accompanying drawings.

[0039] See also Figure 1 , which shows a flow chart of a method for controlling a power supply panel of a secondary power distribution system provided by an embodiment of the present application, the method comprising the following steps:

[0040] Step S101, collecting voltage data of each phase during the operation of the power panel within a preset time period.

[0041] In the power supply of the power panel, three phase lines are used, each phase line has a phase voltage of 220V, and the three phase lines are combined in a star connection to form a 380V bus voltage. The schematic diagram of the star connection is as follows Figure 2 In three-phase alternating current, the voltage phase difference between adjacent phases is The phase difference enables three-phase AC to provide stable power output, which is suitable for various industrial and commercial electrical equipment. The relationship between single-phase voltage and bus voltage is:

[0042] Where V line Represents the bus voltage; V phase Indicates single-phase voltage.

[0043] The power supply of the power panel has three phases. By installing smart meters on each phase line, the voltage data of each phase of the power supply of the power panel can be collected separately.

[0044] In this embodiment, voltage data is collected within a preset time period, the length of the preset time period is 0.1s, and the collection frequency of the voltage data is 10kHz. The length of the preset time period and the collection frequency are preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0045] For each phase line of the power supply of the power panel, the signal form of the voltage of the phase line in the time domain is a sinusoidal signal. Therefore, in order to avoid the influence of environmental noise in the collected data, in this application, a moving average filtering algorithm is used to filter the collected voltage data of each phase. Among them, the moving average filtering algorithm is a well-known technology and will not be described in detail in this application. The implementer can select other feasible filtering methods at his own discretion.

[0046] Step S102, extracting the faulty phase and the phase to be analyzed by comparing the effective value of the voltage data of each phase within the preset time period with the preset threshold value, and switching the power supply of the power panel if there is at least one faulty phase.

[0047] The voltage phase with a ground fault is called a fault phase, and the voltage phase without a ground fault is called a normal phase. When a fault phase exists in the power supply panel, the voltage of the fault phase will drop to 0 or close to 0, while the voltage of the normal phase will rise to the bus voltage. For a normally operating power supply, a voltage error of ±20V is usually allowed in the phase line, that is, the normal single-phase voltage range is between 200V and 240V. Since when a phase ground fault occurs, the voltage of the normal phase is close to the bus voltage, and the voltage of the fault phase is close to 0, therefore, in order to identify the fault of the power supply panel, a first threshold and a second threshold are preset respectively. In order to ensure the accuracy of the detection, the value range of the first threshold is preset to [20,180], and the value range of the second threshold is preset to [260,360], because a 20V error is reserved for the voltage.

[0048] In this embodiment, the values ​​of the preset first threshold and the preset second threshold are 90 and 310 respectively. On the basis of ensuring that the values ​​of the preset first threshold and the preset second threshold can identify the faulty phase and the normal phase, the implementer can set the values ​​of the preset first threshold and the preset second threshold by himself.

[0049] Based on the above analysis, by comparing the effective value of the voltage data of each phase within the preset time period with the preset first threshold and the preset second threshold, the ground fault identification value of each phase is obtained, and the expression is:

[0050] In the formula, Flag A Indicates the ground fault identification value of phase A in the power supply panel; F A Indicates the effective value of phase A in the power supply panel; T d represents the preset first threshold; T grepresents the preset second threshold value; N1, N2 and N3 represent the first preset constant, the second preset constant and the third preset constant respectively, which respectively characterize that phase A belongs to the fault phase, the phase to be analyzed and the normal phase. Among them, the effective value of phase A is the root mean square value of all voltage data of phase A in the preset time period. The calculation of the root mean square value is a well-known technology and will not be repeated in this application.

[0051] In this embodiment, the values ​​of N1, N2 and N3 are -1, 0 and 1 respectively. The values ​​of N1, N2 and N3 are preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0052] For phase B and phase C, the ground fault identification value of phase B and the ground fault identification value of phase C are obtained respectively according to the same method as that of obtaining the ground fault identification value of phase A.

[0053] When the ground fault identification value of any phase is the first preset constant, the any phase is determined to be a faulty phase, and a ground fault is determined to have occurred in the power supply of the power supply panel, and the power supply of the power supply panel is switched from the main power supply to the backup power supply, and the switching method is as in step S106. Further, the ground fault signal is transmitted to the maintenance personnel, and after the maintenance is completed, the maintenance personnel switches the power supply through the manual control button of the power supply panel, and switches the power supply of the power supply panel from the backup power supply to the main power supply.

[0054] If there is only a phase to be analyzed, that is, when the ground fault identification value is the second preset constant, analysis is performed through the following steps.

[0055] Step S103: If there is only a phase to be analyzed, the periodic zero point sequence of each phase is obtained by analyzing the zero-sequence fault of the power supply of the power panel.

[0056] The zero-sequence fault of the power supply panel refers to the situation that when the three-phase voltage of the power supply is unbalanced, the sum of the phase quantities of the three voltage phases is not zero. For the voltage data collected by this application, the sum of the voltage data of the three phases at the same time is no longer zero, and the phase difference between adjacent phases is not equal to

[0057] Based on the above analysis, first, the moment when the voltage data of each phase is 0 is obtained. The waveform of the single-phase voltage in AC is a sine wave, but due to the instability of the voltage in the power supply and the influence of environmental noise, there may be multiple 0 elements in the collected voltage data within a short time range. For 50Hz AC, each cycle of AC requires time, then half an AC cycle requires There is a small time interval between the zero point and the cycle zero point caused by voltage instability and environmental noise, which is less than half the AC cycle time, where the cycle zero point refers to the intersection of the sine wave and the Y=0 axis in the ideal case.

[0058] Further, the moment when the voltage data is 0 is recorded as the 0-value moment. For any phase, the order of all the 0-value moments in the preset neighboring time domain of each 0-value moment in all the acquisition moments is arranged from small to large to form a time series of each 0-value moment, and the mean of all elements in each time series is calculated. In this embodiment, the preset neighboring time domain of each 0-value moment is the time series centered at each 0-value moment. time interval.

[0059] Furthermore, the number of samples of voltage data within half an AC cycle is obtained, and the expression is:

[0060] In the formula, L represents the number of samples of voltage data within half an AC cycle; a represents a preset value. In this embodiment, the value of a is 2, which is used to take half an AC cycle; P represents the number of voltage data collected within a preset time length; and n represents the number of AC cycles within the preset time length.

[0061] In this embodiment, the value of the preset time length is 1s. The value of the preset time length is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0062] Furthermore, the period zero difference of each element in each time series is calculated by the distribution of elements in each time series and its adjacent previous time series, as well as the number of samples of voltage data in half an AC cycle. The expression is:

[0063] hz j,k =|z j,k -Z j-1 -L|; where hz j,k represents the periodic zero point difference of the kth element in the jth time series; z j,k represents the kth element in the jth time series; Z j-1 represents the cycle zero point of the j-1th time series; L represents the number of samples of voltage data within half an AC cycle.

[0064] It should be noted that: when the difference of the period zero point of any element in the time series is smaller, it means that the distance between the said element and the previous period zero point is closer to half an AC cycle, which means that the possibility that the said element is the period zero point is higher. Therefore, the element with the smallest difference of the period zero point in each time series is taken as the period zero point of each time series.

[0065] All periodic zero points of each phase are arranged in time sequence to form a periodic zero point sequence of each phase.

[0066] Step S104, calculating the difference between the elements at the same position between the periodic zero point sequences of any two phases, combining the deviation between the difference and the preset standard difference, to obtain the phase deviation between the any two phases.

[0067] For normal 3-phase AC, the phase difference between adjacent phases is Therefore, by comparing the actual phase difference between adjacent phases with The difference between adjacent phases is calculated, and the phase deviation between adjacent phases is calculated. The specific calculation formula is:

[0068]

[0069]

[0070] Where, Pl A,B Pl A,C Pl B,C Respectively represent the phase deviation between phase A and phase B, phase A and phase C, phase B and phase C; M A,B 、M A,C 、M B,C They represent the minimum number of elements in the periodic zero point sequence of phase A and phase B, the minimum number of elements in the periodic zero point sequence of phase A and phase C, and the minimum number of elements in the periodic zero point sequence of phase B and phase C respectively; Z A,x , Z B,x , Z C,x Respectively represent the xth element in the periodic zero point sequence of phase A, phase B, and phase C; 2π represents the sum of the phase differences between any two adjacent phases; represents the phase difference between any two phases under normal circumstances; P represents the amount of voltage data collected within a preset time length; and n represents the number of AC cycles within the preset time length.

[0071] It should be noted that: when the phase deviation is larger, the phase imbalance of the three-phase AC is higher, indicating that the zero-sequence fault of the power supply panel is more serious. Therefore, when monitoring and processing the power supply of the power supply panel, the larger the phase deviation is, the more attention should be paid, and timely measures should be taken to adjust and repair it. In the power system, keeping the phase deviation small can ensure the stability and reliability of the power supply, provide users with high-quality power supply, and enhance the safety and stability of the power system.

[0072] Step S105: Based on the phase deviation, the power switching of the power panel is controlled.

[0073] Generally, during the operation of the three-phase AC power supply, due to the influence of environmental factors, there may be a certain deviation in the phase difference between adjacent phases of the three-phase AC power supply. When the deviation is within a small range, it is a normal phenomenon. In this embodiment, if the phase deviation between adjacent phases is less than the second preset value, the phase difference between adjacent phases is determined to be normal. Otherwise, the phase difference between adjacent phases is determined to be normal, and the power supply of the power supply panel needs to be switched and controlled immediately, and the power supply of the power supply panel is switched from the main power supply to the backup power supply. The switching method is as shown in step S106. After the power supply of the power supply panel is switched from the main power supply to the backup power supply, according to the phase deviation greater than the second preset value, a digital phase-locked loop is used to correct the phase corresponding to the phase deviation greater than the second preset value. After the correction is completed, the digital phase-locked loop sends a signal to the automatic power switching circuit of the power supply panel, and the automatic power switching circuit switches the power supply of the power supply panel from the backup power supply to the main power supply.

[0074] In this embodiment, the second preset value is 3°. The second preset value is preset manually, and the implementer can set a smaller value by himself to ensure that the phase deviation is controlled within a smaller range.

[0075] Step S106, switching control of the power supply of the power panel.

[0076] Before switching the power supply of the power panel from the main power supply to the backup power supply, the backup power supply is tested to check whether the backup power supply has been successfully started and whether the output voltage and frequency are within the preset range. When the backup power supply has been successfully started and the output voltage and frequency are within the preset range, it means that the backup power supply is in a normal power supply state. Under the premise that the backup power supply is in a normal power supply state, the switching operation is performed, otherwise, the switching operation is not performed. At the same time, in order to prevent malfunctions during the switching process, a certain delay time and switching judgment logic are set, such as switching only after the fault signal is detected multiple times. When the main power supply is working normally, the contactor of the main power supply is energized and attracted, and at the same time, its normally closed contact is disconnected, so that the time relay cannot be energized, ensuring that the backup power supply will not work. During the switching, the main power supply is powered off and the time relay starts timing. After the time relay is energized, its normally open contact is closed to form a self-locking circuit, so that the contactor of the backup power supply is energized and attracted. At this time, the backup power supply starts to supply power. Figure 3 This is the switching control flow chart of the power supply of the power panel.

[0077] In this embodiment, switching is performed only after a fault signal is detected three times, wherein 3 is only one embodiment of the present application, and the implementer can set the specific value according to the actual situation.

[0078] In this embodiment, the preset range of the single-phase output voltage of the backup power supply is 200V~240V, and the preset range of the frequency is 45Hz~55Hz. The preset range of the single-phase output voltage and the preset range of the frequency of the backup power supply can be limited by the implementer according to actual conditions, and this application does not impose any special restrictions.

[0079] Based on the same inventive concept as the above method, an embodiment of the present application also provides a power supply control system for a power supply panel of secondary power distribution, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, it implements the steps of any one of the above-mentioned power supply control methods for a power supply panel of secondary power distribution.

[0080] In summary, the present application is based on the change characteristics of the voltage data of the faulty phase and the normal phase when the power supply of the power supply panel has a ground fault. By comparing the effective value of the voltage data of each phase within a preset time length with the preset threshold, it is determined whether the power supply of the power supply panel has a ground fault. If a ground fault occurs, the power supply of the power supply panel is switched from the main power supply to the backup power supply, which can ensure the stable operation of the power supply panel; further, by analyzing the time distribution of the voltage data being 0 and calculating the cycle zero point of each phase, it is possible to avoid using the zero point caused by voltage instability and environmental noise as the cycle zero point, thereby improving the accuracy of the subsequent calculation of the phase deviation between adjacent phases based on the cycle zero point, and determining whether the phase deviation between adjacent phases exceeds the normal range. If it exceeds, the power supply of the power supply panel is switched from the main power supply to the backup power supply, avoiding the use of the main power supply for power supply when the phase difference of the main power supply is abnormal, which affects the stability of the output power. By analyzing the voltage data during the operation of the power supply panel, various faults of the power supply of the power supply panel can be discovered in time, the sensitivity of fault detection of the power supply of the power supply panel can be improved, and an accurate basis can be provided for the switching control of the power supply of the power supply panel to ensure the stable operation of the power supply of the power supply panel.

[0081] The flowchart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to the embodiment of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowchart and the block diagram in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in a different order from the order disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0082] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic features of the present application. Therefore, no matter from which point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A power supply control method for a power supply panel of a secondary power distribution, characterized in that: The method comprises the following steps: Collect voltage data of each phase of the power panel during operation within a preset time period; By comparing the effective value of the voltage data of each phase within the preset time period with the preset threshold, the fault phase and the phase to be analyzed are extracted, and if there is at least one fault phase, the power supply of the power panel is switched; If there is only a phase to be analyzed, the periodic zero point sequence of each phase is obtained by analyzing the zero-sequence fault of the power supply of the power panel; Calculate the difference between the elements at the same position between the periodic zero point sequences of any two phases, and combine the deviation between the difference and the preset standard difference to obtain the phase deviation between the any two phases; Based on the phase deviation, power switching of the power panel is controlled.

2. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 1, characterized in that: The method for extracting the fault phase and the phase to be analyzed is: The effective value is the root mean square value of all voltage data of each phase within the preset time period; When the effective value of any phase is less than a preset first threshold, determining that any phase is a fault phase; When the effective value of any phase is greater than or equal to the preset first threshold value and less than or equal to the preset second threshold value, it is determined that any phase is the phase to be analyzed.

3. A power supply control method for a power supply panel of a secondary power distribution as claimed in claim 2, characterized in that: The acquisition process of the periodic zero point sequence is: Record the moment when the voltage data is 0 as the 0-value moment, and for any phase, arrange the order of all the 0-value moments in the preset neighboring time domain of each 0-value moment in all the acquisition moments from small to large to form a time series of each 0-value moment; calculate the mean of all elements in each time series; For any time series and its adjacent previous time series, calculate the difference between each element in the any time series and the mean value of the previous time series; By comparing the first preset value with the difference corresponding to each element in the any time series, the period zero point difference of each element in the any time series is obtained, and the element as the period zero point is extracted from the any time series according to the period zero point difference; All periodic zero points of any phase are arranged in time sequence to form a periodic zero point sequence of any phase.

4. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 3, characterized in that: The period zero point difference is the difference between the first preset value and the difference corresponding to each element in any time series.

5. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 3, characterized in that: The periodic zero point is an element with the smallest periodic zero point difference in any time series.

6. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 2, characterized in that: The calculation relationship of the phase deviation is: Where, Pl A,B Indicates the phase deviation between phase A and phase B; M A,B Represents the minimum number of elements in the periodic zero sequence of phase A and phase B; Z A,x , Z B,x Respectively represent the xth element in the periodic zero point sequence of phase A and phase B; P represents the number of voltage data collected within a preset time length; n represents the number of AC cycles within the preset time length; According to the calculation method of the phase deviation between phase A and phase B, the phase deviation between phase A and phase C and the phase deviation between phase B and phase C are calculated respectively.

7. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 1, characterized in that: When the phase deviations between any two phases are all smaller than the second preset value, the power supply of the power supply panel is not switched; otherwise, the power supply of the power supply panel is switched.

8. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 1, characterized in that: Before switching the power supply of the power panel, it is necessary to detect the startup status of the backup power supply and the distribution of output voltage and frequency.

9. A power supply control method for a power supply panel of secondary power distribution as claimed in claim 7, characterized in that: After the power supply of the power supply panel is switched from the main power supply to the backup power supply, feedback control technology is used to correct the phase corresponding to the phase deviation greater than the second preset value according to the phase deviation greater than the second preset value. After the correction is completed, the power supply of the power supply panel is switched from the backup power supply to the main power supply.

10. A power supply control system for a power supply panel of a secondary power distribution, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of a power supply control method for a power supply panel of secondary power distribution are implemented as described in any one of claims 1-9.

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