Power distribution protection control method and device, equipment and storage medium

Abstract

The invention provides a power distribution protection control method and device, equipment and a storage medium. The method comprises the following steps: calculating and monitoring whether an operation parameter in a distribution line is subjected to sudden change starting or not based on second-order difference; if n continuous sampling points of the operation parameters are subjected to sudden change starting, half-wave calculation is carried out by taking the (n + 1) th sampling point of the operation parameters as a starting point, whether a half-wave calculation result is greater than a fault protection fixed value corresponding to the operation parameters is judged, and meanwhile, whether the operation parameters in the distribution line are subjected to sudden change starting is continuously monitored; determining the number of compensation points according to a judgment result and a monitoring result of sudden change restart; and correcting the FFT initial position of the sampling point of the operation parameter according to the number of the compensation points, and carrying out FFT calculation on the sampling point of the operation parameter according to the corrected FFT initial position so as to carry out power distribution protection control based on an FFT calculation result. According to the invention, an instruction for controlling the action of the relay protection device can be output in time, and refusal of action of the current-stage switch or longer outlet time is avoided.

Description

Technical Field

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

[0002] Distribution protection control refers to the process of controlling the relay protection device to quickly isolate the fault after a distribution fault occurs.

[0003] During the distribution protection control process, if a distribution fault occurs, the corresponding voltage or current analog value will experience a sudden change. To eliminate slow changes, highlight the sudden acceleration caused by the fault, and improve fault detection sensitivity, a second-order difference calculation is generally used to determine whether the sudden change has occurred. Specifically, the calculation X3[m]-2X2[m]+X1[m] is used to determine whether the corresponding voltage or current analog value has experienced a sudden change. Here, X1 represents the current cycle of the corresponding voltage or current analog value, X2 represents the previous cycle of the corresponding voltage or current analog value, X3 represents the previous two cycles of the corresponding voltage or current analog value, and m represents the mth sampling point in each cycle. If the second-order difference calculation result is greater than the sudden change value, the sudden change is initiated, and the corresponding sudden change start flag is set. It takes two cycles for the sudden change start flag to return to its initial state. Moreover, in order to prevent interference and avoid malfunction of the device, mutation filtering is performed after the mutation start judgment. When the second-order difference calculation result of n consecutive sampling points (n is the mutation start filtering constant) is greater than the mutation constant, a fast Fourier transform (FFT) calculation is performed based on the sampling point of one cycle after n sampling points, and the instruction for controlling the action of the relay protection device is output based on the FFT calculation result.

[0004] However, the inventors discovered that in the current distribution protection control process, since the starting point of the FFT calculation is not the moment corresponding to the sudden change start, but the moment after the sudden change start filter constant, the time from the occurrence of the fault to the acquisition of the FFT calculation result will be greater than 1 cycle, which in turn causes the exit time of the distribution protection control to become longer (that is, the time for outputting the instruction to control the action of the relay protection device to become longer). Moreover, if multiple sudden change starts occur within 2 cycles after the sudden change start flag is set, it will also cause the switch at this level to refuse to operate or the exit time to become longer, and the instruction to control the action of the relay protection device cannot be output in time. Summary of the Invention

[0005] Embodiments of the present invention provide a power distribution protection control method, device, equipment and storage medium to solve the problem that the current power distribution protection control process may not output instructions for controlling the action of the relay protection device in a timely manner, resulting in the failure of the switch at this level to operate or the prolonged exit time.

[0006] In a first aspect, an embodiment of the present invention provides a power distribution protection control method, comprising:

[0007] Based on the second-order difference calculation, the monitoring of the operating parameters in the distribution line is started to see whether there is a sudden change;

[0008] If the operating parameter has a sudden change at n consecutive sampling points, a half-wave calculation is performed starting from the n+1th sampling point of the operating parameter to determine whether the half-wave calculation result is greater than the fault protection setting corresponding to the operating parameter. At the same time, the operating parameter in the distribution line is continuously monitored to see if a sudden change occurs before restarting, where n is the sudden change start filter setting;

[0009] Determine the number of compensation points based on the judgment results and the monitoring results of the sudden change restart;

[0010] The FFT starting position of the sampling point of the operating parameter is corrected according to the number of compensation points, and the FFT calculation is performed on the sampling point of the operating parameter according to the corrected FFT starting position, so as to perform distribution protection control based on the FFT calculation result.

[0011] In a possible implementation, determining the number of compensation points based on the judgment result and the monitoring result of the sudden change restart includes:

[0012] If the half-wave calculation result is greater than the fault protection setting value and no sudden change is detected before restarting, the number of compensation points is determined according to the sudden change start filter setting value;

[0013] If the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, the number of first compensation points is determined according to the sudden change start filter set value, and the number of second compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filter set value;

[0014] If the half-wave calculation result is less than or equal to the fault protection set value and no sudden change is detected before restarting, the number of compensation points is determined to be zero;

[0015] If the half-wave calculation result is less than or equal to the fault protection constant and a sudden change is detected, the number of compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filtering constant.

[0016] In a possible implementation, starting a filtering setting according to the mutation amount to determine the number of compensation points includes:

[0017] Determine the mutation amount start filtering constant as the number of compensation points;

[0018] Alternatively, starting a filtering constant according to the mutation amount to determine the first number of compensation points includes:

[0019] The sudden change amount start filtering constant is determined as the first compensation point number.

[0020] In a possible implementation, determining the number of second compensation points according to the number of sampling points when the sudden change is restarted and the sudden change start filtering constant includes:

[0021] Calculating the difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted, and calculating the sum of the difference and the mutation amount startup filter constant, and determining the sum as the second compensation point number;

[0022] Alternatively, the number of compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filtering constant, including:

[0023] The difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted is calculated, and the sum of the difference and the mutation amount startup filter constant is calculated, and the sum is determined as the number of compensation points.

[0024] In a possible implementation, correcting an FFT starting position of a sampling point of the operating parameter according to the number of compensation points, and performing FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position includes:

[0025] If the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, then after determining that the half-wave calculation result is greater than the fault protection set value, the FFT starting position of the sampling point of the operating parameter is corrected for the first time according to the first compensation point number, and the sampling point of the operating parameter is calculated for the first time according to the first corrected FFT starting position; after detecting that the sudden change is detected and restarted, the FFT starting position of the sampling point of the operating parameter is corrected for the second time according to the second compensation point number, and the sampling point of the operating parameter is calculated for the second time according to the second corrected FFT starting position.

[0026] In a possible implementation, the operating parameters include phase current and zero-sequence current;

[0027] Before starting to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation, the following steps are also included:

[0028] If the fault protection of the phase current is activated, the sudden change constant of the phase current is corrected according to the product of the fault protection constant corresponding to the fault protection level of the phase current activated and a preset ratio;

[0029] If the zero-sequence current fault protection is activated, the zero-sequence current sudden change constant is corrected according to the product of the fault protection constant corresponding to the zero-sequence current fault protection level and a preset ratio.

[0030] In a possible implementation, the operating parameter includes a zero-sequence voltage;

[0031] Before starting to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation, the following steps are also included:

[0032] If the zero-sequence voltage fault protection is activated, the zero-sequence voltage mutation constant is corrected according to the product of the fault protection constant corresponding to the zero-sequence voltage and a preset ratio.

[0033] In a second aspect, an embodiment of the present invention provides a power distribution protection control device, comprising:

[0034] The first processing module is used to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation;

[0035] The second processing module is configured to, if the operating parameter undergoes a sudden change at n consecutive sampling points, perform a half-wave calculation starting from the n+1th sampling point of the operating parameter, determine whether the half-wave calculation result is greater than the fault protection setting corresponding to the operating parameter, and continue to monitor the operating parameter in the distribution line for a sudden change before restarting, wherein n is the sudden change start filter setting;

[0036] The third processing module is used to determine the number of compensation points based on the judgment result and the monitoring result of the sudden change restart;

[0037] The power distribution protection control module is used to correct the FFT starting position of the sampling point of the operating parameter according to the number of compensation points, perform FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position, and perform power distribution protection control based on the FFT calculation results.

[0038] In a third aspect, an embodiment of the present invention provides a power distribution protection and control device, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0039] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0040] Embodiments of the present invention provide a distribution protection control method, apparatus, device and storage medium, which monitor whether the operating parameters in the distribution line have a sudden start-up based on second-order difference calculation; if the operating parameters have a sudden start-up at n consecutive sampling points, a half-wave calculation is performed with the n+1th sampling point of the operating parameter as the starting point to determine whether the half-wave calculation result is greater than the fault protection constant corresponding to the operating parameter, and at the same time continue to monitor whether the operating parameters in the distribution line have a sudden start-up, where n is the sudden start-up filter constant; the number of compensation points is determined based on the judgment result and the monitoring result of the sudden start-up; the FFT starting position of the sampling point of the operating parameter is corrected based on the number of compensation points, and the FFT calculation is performed on the sampling point of the operating parameter based on the corrected FFT starting position, so as to perform distribution protection control based on the FFT calculation result. Then, the half-wave calculation results are used to preliminarily judge whether fault protection is needed, and the sudden quantity startup within two cycles after the sudden quantity startup is identified through the monitoring of the sudden quantity restart. The preliminary judgment results of the fault protection and the monitoring results of the sudden quantity restart are combined to accurately determine the number of sampling points that need to be compensated for the FFT starting position (that is, the number of compensation points), and then accurately determine the FFT starting position, and perform FFT calculation in time according to the accurate FFT starting position, and output the command to control the action of the relay protection device in time according to the FFT calculation results, so as to avoid the refusal of the switch at this level to operate or the prolonged exit time. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 This is a flow chart of an implementation of a power distribution protection control method provided by an embodiment of the present invention;

[0043] Figure 2 1 is a schematic structural diagram of a power distribution protection control device provided by an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of a power distribution protection control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below with reference to the accompanying drawings.

[0047] Before describing the power distribution protection control process according to an embodiment of the present invention, the current power distribution protection control process is described:

[0048] At present, in the distribution protection control process, 32 sampling points are calculated per cycle (i.e., one power frequency cycle). When making a sudden change start judgment:

[0049] The sudden change value is calculated using a second-order difference calculation (i.e., X3[m] - 2X2[m] + X1[m]) to eliminate slow changes, highlight sudden accelerations caused by faults, and improve fault detection sensitivity. When the sudden change value exceeds the sudden change value, the protection sudden change is activated, the sudden change start flag is set, and the protection returns after two cycles.

[0050] To prevent malfunctions caused by interference, a sudden change filtering process is also performed. Specifically, when the sudden change value calculated for n consecutive sampling points (the sudden change filter setting, which can be set) exceeds the sudden change setting, these n sampling points are discarded, and the FFT calculation is performed on the sampling points one cycle after the n sampling points. The FFT calculation result is used to output the command to control the operation of the relay protection device.

[0051] However, the current distribution protection control process still has the following problems:

[0052] 1. When a fault occurs, the FFT calculation starts not at the moment the sudden value is activated, but after the set sudden value activation filter value has been reached. Therefore, the time from the fault occurrence to the FFT calculation result will exceed one cycle (the FFT calculates one cycle sampling point), resulting in a longer output time. For example, if the sudden value activation filter value is 3, using 32 sampling points per cycle for FFT calculation and filtering 3 sampling points, the output time will be slower by 3 / 32*20=1.875ms.

[0053] 2. When multiple sudden quantity starts occur in a short period of time, since the sudden quantity needs to return to the initial state after 2 cycles, the sudden quantity starts that occur again after the initial sudden quantity start may not be detected, which may cause the switch at this level to refuse to operate or the exit time to slow down.

[0054] For the above issues, see Figure 1 , which shows a flow chart for implementing the power distribution protection control method provided by an embodiment of the present invention, and is described in detail as follows:

[0055] In step 101, a monitoring is performed based on second-order difference calculation to determine whether an operating parameter in a distribution line has undergone a sudden change.

[0056] Exemplarily, the operating parameters in the distribution line may include phase current, zero-sequence current, and zero-sequence voltage.

[0057] Before starting to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation, the following steps are also included:

[0058] If the phase current fault protection is enabled, the phase current sudden change value is corrected according to the product of the fault protection value corresponding to the fault protection level of the phase current enabled and the preset ratio;

[0059] If the zero-sequence current fault protection is activated, the zero-sequence current sudden change value is corrected according to the product of the fault protection value corresponding to the zero-sequence current fault protection level and the preset ratio.

[0060] If the zero-sequence voltage fault protection is activated, the zero-sequence voltage mutation constant is corrected according to the product of the fault protection constant corresponding to the zero-sequence voltage and the preset ratio.

[0061] This embodiment addresses the problem of multiple sudden quantity starts in a short period of time, and automatically adjusts the sudden quantity constant after the device is powered on.

[0062] For example, for the sudden change value of the phase current:

[0063] If phase current-related fault protection is enabled (for example, three-stage overcurrent fault protection is enabled), the phase current sudden change value is initialized to 20% of the fault protection value corresponding to the three-stage overcurrent fault. If at least two fault protection levels are enabled, for example, three-stage overcurrent and two-stage overcurrent, the phase current sudden change value is initialized to 20% of the minimum of the two fault protection values ​​corresponding to the three-stage overcurrent fault and the two-stage overcurrent fault.

[0064] If all phase current related fault protections are exited, the phase current sudden change value is initialized to the maximum, for example, 65535.

[0065] For the sudden change value of zero sequence current:

[0066] If zero-sequence current-related fault protection is enabled (for example, zero-sequence current three-stage fault protection is enabled), the zero-sequence current sudden change value is initialized to 20% of the fault protection value corresponding to zero-sequence current three-stage. If at least two fault protection levels are enabled, for example, zero-sequence current three-stage and zero-sequence current two-stage, the zero-sequence current sudden change value is initialized to 20% of the minimum of the fault protection values ​​corresponding to zero-sequence current three-stage and zero-sequence current two-stage.

[0067] If all zero-sequence current related fault protections are exited, the zero-sequence current sudden change value is initialized to the maximum, for example, 65535.

[0068] The corresponding sudden change value of zero-sequence voltage is:

[0069] When zero-sequence voltage related fault protection is activated (such as acceleration after zero voltage), the zero-sequence voltage sudden change value is initialized to 20% of the fault protection value corresponding to acceleration after zero voltage.

[0070] The zero-sequence voltage related fault protection is exited, and the zero-sequence voltage sudden change value is initialized to the maximum, for example 65535.

[0071] Among them, the fault protection setting value is obtained by professionals through detailed load and impedance calculations. Therefore, the sudden change setting value is automatically adjusted according to the fault protection setting value, specifically according to 20% of the fault protection setting value. This helps to ensure the export time while minimizing the number of sudden change starts.

[0072] The preset ratio is set to 20% to account for the requirement that, during distribution protection control, the fault handling delay should meet the following requirements: When the overload protection is at 1.2 times the set value, the delay should be no more than 1%, or 40ms. To meet these requirements, sudden tripping can be performed when the phase current, zero-sequence current, or zero-sequence voltage suddenly changes to 1.2 times the set value (i.e., the fault protection setting) to ensure timely exit. While minimizing the number of sudden tripping events, the maximum preset ratio can be set to 20%.

[0073] In step 102, if the operating parameter starts with a sudden change at n consecutive sampling points, a half-wave calculation is performed starting from the n+1th sampling point of the operating parameter to determine whether the half-wave calculation result is greater than the fault protection constant corresponding to the operating parameter. At the same time, the operating parameter in the distribution line is continuously monitored to see if a sudden change occurs before starting, where n is the sudden change start filter constant.

[0074] This embodiment takes into account that when a line fault occurs, the fault current or fault voltage will persist before the relay protection device operates. The distribution protection control device collects a continuous and sudden increase in the fault current or fault voltage. However, the FFT calculation result requires sampling a full cycle of data (20ms, including two half-cycles). Therefore, when the sudden increase is activated, the half-cycle calculation is performed first. If the calculated result is greater than the fault protection set value, it is likely that a fault has occurred. Then, n sampling points of the compensation filter are compensated and the full cycle is recalculated.

[0075] In addition, in order to solve the problem of multiple sudden quantity starts in a short period of time, considering that the original distribution protection control process does not judge the window period of one cycle from the fault to the return of the sudden quantity after one cycle sampling point after the sudden quantity is started and calculated, the operating parameters in the distribution line are continuously monitored to see if there is a sudden quantity restart, so as to distinguish and compensate for the sudden quantity start that occurs again during this window period and the initial sudden quantity start.

[0076] In step 103, the number of compensation points is determined based on the judgment result and the monitoring result of the sudden change restart.

[0077] Optionally, determining the number of compensation points based on the judgment result and the monitoring result of the sudden change restart may include:

[0078] If the half-wave calculation result is greater than the fault protection setting and no sudden change is detected before restarting, the number of compensation points is determined based on the sudden change start filter setting.

[0079] If the half-wave calculation result is greater than the fault protection constant and a sudden change is detected, the number of first compensation points is determined according to the sudden change start filter constant, and the number of second compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filter constant.

[0080] If the half-wave calculation result is less than or equal to the fault protection setting value and no sudden change is detected before restarting, the number of compensation points is determined to be zero.

[0081] If the half-wave calculation result is less than or equal to the fault protection setting, and a sudden change is detected, the number of compensation points is determined based on the number of sampling points when the sudden change is restarted and the sudden change start filter setting.

[0082] Exemplarily, determining the number of compensation points based on the sudden change amount starting filtering constant value includes:

[0083] The sudden change amount start filter constant is determined as the number of compensation points.

[0084] Exemplarily, determining the first number of compensation points according to the sudden change amount starting filtering constant value includes:

[0085] The sudden change amount start filtering constant is determined as the first compensation point number.

[0086] Exemplarily, determining the second compensation point number according to the number of sampling points when the sudden change quantity is restarted and the sudden change quantity startup filter constant includes:

[0087] Calculate the difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted, and calculate the sum of the difference and the mutation amount startup filter constant, and determine the sum as the number of second compensation points;

[0088] Exemplarily, determining the number of compensation points according to the number of sampling points when the sudden change quantity is restarted and the sudden change quantity startup filter constant includes:

[0089] Calculate the difference between the number of sampling points of the operating parameters in two cycles and the number of sampling points when the mutation quantity is restarted, and calculate the sum of the difference and the mutation quantity startup filter constant, and determine the sum as the number of compensation points.

[0090] In this embodiment, after the half-wave calculation, if the half-wave calculation result is greater than the fault protection set value, it indicates that a fault has likely occurred and fault protection is required. In this case, since the sudden change value returns two cycles after activation, there is a one-cycle window period from the moment the sudden change value is activated and calculated (no fault is detected) to the moment the sudden change value returns. If a fault occurs during this window period, the device's exit time will be extended.

[0091] Therefore, a new "mutation restart flag" is added. If no fault is detected after one cycle sampling point after the mutation is started and calculated, and no mutation is started again before the mutation returns, then the n sampling points of the filter can be directly compensated.

[0092] If a fault is not detected after one sampling point of the sudden value activation and calculation, and a sudden value activation occurs again before the sudden value returns, the "sudden value restart flag" is set, and the counter value f of the "post-sudden value activation return counter" is read. f is the number of sampling points from the sudden value activation to the sudden value restart. The existing distribution protection control process, without the "sudden value restart flag," ignores the sampling points after the sudden value restart. Therefore, this embodiment calculates the sampling points ignored after the sudden value restart based on the difference 64-f. These are then added to the n sampling points from the initial sudden value activation filtering, and the total number of compensation points is calculated using the formula p = 64-f + n. Here, 64 is the number of sampling points for two cycles.

[0093] Similarly, after the half-wave calculation, if the half-wave calculation result is less than or equal to the fault protection setting, two cases are also considered, namely, the case where the "sudden change restart flag" is not set and is set.

[0094] If the half-wave calculation result is less than or equal to the fault protection setting value and the "mutation restart flag" is not set, it means that the initial mutation start is likely to be interference, and no mutation start occurs within 2 cycles after the initial mutation start. In this case, the number of compensation points can be set to zero, and no compensation is required. Just wait for the mutation start flag to return to the initial state.

[0095] If the half-wave calculation result is less than or equal to the fault protection set value and the "mutation restart flag" is set, it means that the initial mutation start is likely to be interference. However, if a mutation start occurs again within 2 cycles after the initial mutation start, the total number of compensation points can be calculated based on p = 64-f+n.

[0096] In step 104, the FFT starting position of the sampling point of the operating parameter is corrected according to the number of compensation points, and FFT calculation is performed on the sampling point of the operating parameter according to the corrected FFT starting position, so as to perform distribution protection control based on the FFT calculation result.

[0097] Optionally, correcting the FFT starting position of the sampling point of the operating parameter according to the number of compensation points, and performing FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position may include:

[0098] If the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, after determining that the half-wave calculation result is greater than the fault protection set value, the FFT starting position of the sampling point of the operating parameter is corrected for the first time according to the number of first compensation points, and the first FFT calculation is performed on the sampling point of the operating parameter according to the first corrected FFT starting position; after the sudden change is detected and restarted, the FFT starting position of the sampling point of the operating parameter is corrected for the second time according to the number of second compensation points, and the second FFT calculation is performed on the sampling point of the operating parameter according to the second corrected FFT starting position.

[0099] For example, the FFT starting position can be recorded as FFT_head, which is adjusted once every full cycle, and generally caches 4 cycles, that is, the FFT starting position is generally 0 / 32 / 64 / 96 cycles. After determining the number of compensation points, if the number of compensation points is n, FFT_head can be assigned to FFT_head-n. If the number of compensation points is p, FFT_head can be assigned to FFT_head-p. If the FFT_head is less than 0 after assignment, for example, the original FFT starting position is 0, the number of compensation points n is 3, and the FFT_head after amplitude is -3, then considering that 4 cycles are cached, the FFT_head after amplitude can be added to 128 to obtain the final FFT_head.

[0100] After obtaining the final FFT_head, an FFT calculation is performed every time 32 sampling points are collected, and the protection logic is executed according to the FFT calculation results.

[0101] This embodiment of the present invention compensates for the extended exit time caused by sudden change filtering by adjusting the starting position of the fast Fourier transform. Furthermore, this extended exit time is optimized by adding a sudden change judgment and compensation within the window period between the start of the sudden change and the return of the sudden change. Furthermore, this embodiment of the present invention optimizes the situation where multiple sudden changes are activated in a short period of time by automatically adjusting the sudden change constant.

[0102] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0103] The following are device embodiments of the present invention. For details not fully described therein, reference may be made to the corresponding method embodiments described above.

[0104] Figure 2 The following is a schematic diagram of the structure of a power distribution protection control device provided by an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0105] like Figure 2 As shown, the power distribution protection control device includes: a first processing module 21 , a second processing module 22 , a third processing module 33 and a power distribution protection control module 34 .

[0106] The first processing module 21 is used to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation;

[0107] The second processing module 22 is configured to perform a half-wave calculation starting from the n+1th sampling point of the operating parameter if a sudden change in the operating parameter occurs at n consecutive sampling points, determine whether the half-wave calculation result is greater than the fault protection setting corresponding to the operating parameter, and continue to monitor the operating parameter in the distribution line to see if a sudden change occurs before restarting, where n is the sudden change starting filter setting;

[0108] The third processing module 23 is used to determine the number of compensation points based on the judgment result and the monitoring result of the sudden change restart;

[0109] The power distribution protection control module 24 is used to correct the FFT starting position of the sampling point of the operating parameter according to the number of compensation points, perform FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position, and perform power distribution protection control based on the FFT calculation result.

[0110] An embodiment of the present invention monitors whether an operating parameter in a distribution line has a sudden start-up based on second-order difference calculation; if an operating parameter has a sudden start-up at n consecutive sampling points, a half-wave calculation is performed starting from the n+1th sampling point of the operating parameter to determine whether the half-wave calculation result is greater than the fault protection constant corresponding to the operating parameter, and at the same time, the operating parameter in the distribution line is continuously monitored for a sudden start-up, wherein n is a sudden start-up filter constant; the number of compensation points is determined based on the judgment result and the monitoring result of the sudden start-up; the FFT starting position of the sampling point of the operating parameter is corrected based on the number of compensation points, and the FFT calculation is performed on the sampling point of the operating parameter based on the corrected FFT starting position, so as to perform distribution protection control based on the FFT calculation result. Then, the half-wave calculation results are used to preliminarily judge whether fault protection is needed, and the sudden quantity startup within two cycles after the sudden quantity startup is identified through the monitoring of the sudden quantity restart. The preliminary judgment results of the fault protection and the monitoring results of the sudden quantity restart are combined to accurately determine the number of sampling points that need to be compensated for the FFT starting position (that is, the number of compensation points), and then accurately determine the FFT starting position, and perform FFT calculation in time according to the accurate FFT starting position, and output the command to control the action of the relay protection device in time according to the FFT calculation results, so as to avoid the refusal of the switch at this level to operate or the prolonged exit time.

[0111] In one possible implementation, the third processing module 23 can be used to determine the number of compensation points according to the mutation quantity startup filter constant if the half-wave calculation result is greater than the fault protection constant and the mutation quantity restart is not detected; if the half-wave calculation result is greater than the fault protection constant and the mutation quantity restart is detected, the first number of compensation points is determined according to the mutation quantity startup filter constant, and the second number of compensation points is determined according to the number of sampling points at the mutation quantity restart and the mutation quantity startup filter constant; if the half-wave calculation result is less than or equal to the fault protection constant and the mutation quantity restart is not detected, the number of compensation points is determined to be zero; if the half-wave calculation result is less than or equal to the fault protection constant and the mutation quantity restart is detected, the number of compensation points is determined according to the number of sampling points at the mutation quantity restart and the mutation quantity startup filter constant.

[0112] In a possible implementation, the third processing module 23 may be configured to determine the sudden change amount starting filtering constant as the number of compensation points; or determine the sudden change amount starting filtering constant as the first number of compensation points.

[0113] In one possible implementation, the third processing module 23 can be used to calculate the difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted, and calculate the sum of the difference and the mutation amount startup filter constant, and determine the sum as the second compensation point number; or calculate the difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted, and calculate the sum of the difference and the mutation amount startup filter constant, and determine the sum as the compensation point number.

[0114] In one possible implementation, the power distribution protection control module 24 can be used to, if the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, then after determining that the half-wave calculation result is greater than the fault protection set value, perform a first correction on the FFT starting position of the sampling point of the operating parameter according to the first number of compensation points, and perform a first FFT calculation on the sampling point of the operating parameter according to the first corrected FFT starting position; after monitoring the sudden change and restarting, perform a second correction on the FFT starting position of the sampling point of the operating parameter according to the second number of compensation points, and perform a second FFT calculation on the sampling point of the operating parameter according to the second corrected FFT starting position.

[0115] In one possible implementation, the operating parameters include phase current and zero-sequence current; the first processing module 21 can also be used to correct the sudden change constant of the phase current according to the product of the fault protection constant corresponding to the fault protection level of the phase current and a preset ratio if the fault protection of the phase current is activated; if the fault protection of the zero-sequence current is activated, correct the sudden change constant of the zero-sequence current according to the product of the fault protection constant corresponding to the fault protection level of the zero-sequence current and a preset ratio.

[0116] In one possible implementation, the operating parameters include zero-sequence voltage; the first processing module 21 can also be used to correct the zero-sequence voltage mutation constant according to the product of the fault protection constant corresponding to the zero-sequence voltage and a preset ratio if the zero-sequence voltage fault protection is activated.

[0117] Figure 3 Schematic diagram of the power distribution protection control device provided by the embodiment of the present invention. Figure 3 As shown, the power distribution protection control device 3 of this embodiment includes: a processor 30 and a memory 31. The memory 31 stores a computer program 32. When the processor 30 executes the computer program 32, the steps of the above-described method embodiments are implemented. Alternatively, when the processor 30 executes the computer program 32, the functions of the modules / units in the above-described device embodiments are implemented.

[0118] Exemplarily, the computer program 32 may be divided into one or more modules / units, which are stored in the memory 31 and executed by the processor 30 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 32 in the power distribution protection control device 3.

[0119] The power distribution protection control device 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will understand that Figure 3 It is only an example of the distribution protection control device 3 and does not constitute a limitation of the distribution protection control device 3. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the distribution protection control device 3 may also include input and output devices, network access equipment, buses, etc.

[0120] The processor 30 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0121] The memory 31 can be an internal storage unit of the power distribution protection and control device 3, such as a hard disk or memory of the power distribution protection and control device 3. The memory 31 can also be an external storage device of the power distribution protection and control device 3, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the power distribution protection and control device 3. Furthermore, the memory 31 can also include both an internal storage unit of the power distribution protection and control device 3 and an external storage device. The memory 31 is used to store the computer program 32 and other programs and data required by the power distribution protection and control device 3. The memory 31 can also be used to temporarily store data that has been output or is about to be output.

[0122] For the sake of convenience and brevity, the division of the above functional modules / units is only used as an example. In actual applications, the above functions can be assigned to different functional modules / units as needed. The above modules / units can be implemented in the form of hardware, software, or a combination of hardware and software.

[0123] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods in the above-mentioned method embodiments.

[0124] An embodiment of the present invention further provides a computer program product, including a computer program, which, when executed by a processor, implements the methods in the above-mentioned method embodiments.

[0125] The computer program includes computer program code, which may be in source code form, object code form, executable file, or some intermediate form. Computer-readable media may include any entity or device capable of carrying computer program code, recording media, USB flash drives, mobile hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunications signals, and software distribution media.

[0126] In the above embodiments, the descriptions of each embodiment have their own focus. For parts not described or recorded in detail in one embodiment, please refer to the relevant descriptions of other embodiments. Unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features of different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0127] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A power distribution protection control method, characterized in that: include: Based on the second-order difference calculation, the monitoring of the operating parameters in the distribution line is started to see whether there is a sudden change; If the operating parameter has a sudden change at n consecutive sampling points, a half-wave calculation is performed starting from the n+1th sampling point of the operating parameter to determine whether the half-wave calculation result is greater than the fault protection setting corresponding to the operating parameter. At the same time, the operating parameter in the distribution line is continuously monitored to see if a sudden change occurs before restarting, where n is the sudden change start filter setting; Determine the number of compensation points based on the judgment results and the monitoring results of the sudden change restart; The FFT starting position of the sampling point of the operating parameter is corrected according to the number of compensation points, and the FFT calculation is performed on the sampling point of the operating parameter according to the corrected FFT starting position, so as to perform distribution protection control based on the FFT calculation result.

2. The power distribution protection control method according to claim 1, characterized in that: The method of determining the number of compensation points based on the judgment result and the monitoring result of the sudden change restart comprises: If the half-wave calculation result is greater than the fault protection setting value and no sudden change is detected before restarting, the number of compensation points is determined according to the sudden change start filter setting value; If the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, the number of first compensation points is determined according to the sudden change start filter set value, and the number of second compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filter set value; If the half-wave calculation result is less than or equal to the fault protection set value and no sudden change is detected before restarting, the number of compensation points is determined to be zero; If the half-wave calculation result is less than or equal to the fault protection constant and a sudden change is detected, the number of compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filtering constant.

3. The power distribution protection control method according to claim 2, characterized in that: The number of compensation points is determined by starting a filter setting according to the mutation amount, including: Determine the mutation amount start filtering constant as the number of compensation points; Alternatively, starting a filtering constant according to the mutation amount to determine the first number of compensation points includes: The sudden change amount start filtering constant is determined as the first compensation point number.

4. The power distribution protection control method according to claim 2, characterized in that: Determining the number of second compensation points according to the number of sampling points when the sudden change value is restarted and the sudden change value startup filter constant includes: Calculating the difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted, and calculating the sum of the difference and the mutation amount startup filter constant, and determining the sum as the second compensation point number; Alternatively, the number of compensation points is determined according to the number of sampling points when the sudden change is restarted and the sudden change start filtering constant, including: The difference between the number of sampling points of the operating parameter in two cycles and the number of sampling points when the mutation amount is restarted is calculated, and the sum of the difference and the mutation amount startup filter constant is calculated, and the sum is determined as the number of compensation points.

5. The power distribution protection control method according to claim 2, characterized in that: Correcting an FFT starting position of a sampling point of the operating parameter according to the number of compensation points, and performing FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position, including: If the half-wave calculation result is greater than the fault protection set value and a sudden change is detected and restarted, then after determining that the half-wave calculation result is greater than the fault protection set value, the FFT starting position of the sampling point of the operating parameter is corrected for the first time according to the first compensation point number, and the sampling point of the operating parameter is calculated for the first time according to the first corrected FFT starting position; after detecting that the sudden change is detected and restarted, the FFT starting position of the sampling point of the operating parameter is corrected for the second time according to the second compensation point number, and the sampling point of the operating parameter is calculated for the second time according to the second corrected FFT starting position.

6. The power distribution protection control method according to claim 1, characterized in that: The operating parameters include phase current and zero-sequence current; Before starting to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation, the following steps are also included: If the fault protection of the phase current is activated, the sudden change constant of the phase current is corrected according to the product of the fault protection constant corresponding to the fault protection level of the phase current activated and a preset ratio; If the zero-sequence current fault protection is activated, the zero-sequence current sudden change constant is corrected according to the product of the fault protection constant corresponding to the zero-sequence current fault protection level and a preset ratio.

7. The power distribution protection control method according to claim 1, characterized in that: The operating parameters include zero-sequence voltage; Before starting to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation, the following steps are also included: If the zero-sequence voltage fault protection is activated, the zero-sequence voltage mutation constant is corrected according to the product of the fault protection constant corresponding to the zero-sequence voltage and a preset ratio.

8. A power distribution protection control device, characterized in that: include: The first processing module is used to monitor whether the operating parameters in the distribution line have a sudden change based on the second-order difference calculation; The second processing module is configured to, if the operating parameter undergoes a sudden change at n consecutive sampling points, perform a half-wave calculation starting from the n+1th sampling point of the operating parameter, determine whether the half-wave calculation result is greater than the fault protection setting corresponding to the operating parameter, and continue to monitor the operating parameter in the distribution line for a sudden change before restarting, wherein n is the sudden change start filter setting; The third processing module is used to determine the number of compensation points based on the judgment result and the monitoring result of the sudden change restart; The power distribution protection control module is used to correct the FFT starting position of the sampling point of the operating parameter according to the number of compensation points, perform FFT calculation on the sampling point of the operating parameter according to the corrected FFT starting position, and perform power distribution protection control based on the FFT calculation results.

9. A power distribution protection and control device, characterized in that: The method comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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