A meter box level multi-channel indoor short circuit fault identification method and system

Abstract

The application discloses a kind of meter box level multi-channel indoor short-circuit fault identification method and system, this method includes: first, according to the sampling period set to meter box total incoming line and each user passage incoming line current sampling;Second, find out the current mutation value of meter box total incoming line and user passage incoming line, and record mutation time;Then compare the current mutation time of meter box total incoming line and user passage incoming line, to judge whether the current mutation value of user passage incoming line is real mutation data;Finally, based on multi-channel mutation condition analysis, identify real short-circuit data from real mutation data.Compared with prior art, the application does not need to modify hardware sampling circuit, only based on existing current channel and the sampling data of meter box total incoming line, reduce the probability of fault misjudgment by multidimensional data analysis, effectively reduce the probability of fault misjudgment, improve the reliability of indoor short-circuit fault judgment.

Description

Technical Field

[0001] This invention relates to a meter box-level multi-channel indoor short-circuit fault identification method and system, belonging to the field of power research technology. Background Technology

[0002] Currently, short circuit faults in residential homes are mostly determined by current. Generally, the range of current acquisition equipment on the user side is within 80A, while the short circuit current can reach more than 200A. Therefore, when one of the currents exceeds the acquisition range of the equipment, the change in the reference may cause misjudgment of short circuit faults in all channels. In addition, the opening of some large loads on the power grid line will generate some inrush current, which can also easily cause misjudgment of short circuit faults.

[0003] Therefore, it is necessary to design a multi-channel indoor short-circuit fault identification method that can identify high-current faults at a lower cost and effectively improve the reliability of indoor short-circuit fault identification. Summary of the Invention

[0004] Purpose of the invention: To address the problems existing in the prior art, the present invention provides a multi-channel indoor short-circuit fault identification method and system at the meter box level. It does not require modification of the hardware sampling circuit, but only relies on the sampling data of the existing current channel and the main incoming line of the meter box. Through multi-dimensional data analysis, it reduces the probability of false faults and false alarms, and improves the reliability of indoor short-circuit fault identification.

[0005] Technical Solution: To achieve the above objectives, this invention provides a multi-channel indoor short-circuit fault identification method at the meter box level, comprising the following steps:

[0006] Step 1: Obtain the current fluctuation values ​​of the main incoming line of the meter box and the incoming lines of each user channel, and record the fluctuation time;

[0007] Step 2: Compare the current change times of the main incoming line of the meter box and the incoming line of the user channel to determine whether the current change value of the incoming line of the user channel is the real change data;

[0008] Step 3: Based on the analysis of multi-channel mutations, identify the real short-circuit data from the real mutation data.

[0009] Furthermore, step 1 specifically includes:

[0010] The current of the main incoming line of the meter box and the incoming lines of each user channel are sampled according to the set sampling period;

[0011] For the sampling data of each user channel incoming line, calculate the sudden change value of two current points with an interval of t sampling periods, and filter out the current sudden change value that is greater than the current sudden change threshold A, and record the corresponding sudden change time Ts[x], where x represents the channel number where the sudden change occurred;

[0012] For the sampling data of the main incoming line of the meter box, calculate the sudden change value of two current points with an interval of t sampling periods, and filter out the current sudden change value that is greater than the current sudden change threshold B, and record the corresponding sudden change time Ts[y], where y represents the phase in which the sudden change occurs.

[0013] Furthermore, step 2 specifically includes:

[0014] If there are current abrupt changes in the corresponding phases of the user channel incoming line and the meter box main incoming line, and the interval ΔT between the abrupt changes does not exceed the time threshold C, then the current abrupt change value of the user channel incoming line is considered a true abrupt change; otherwise, the current abrupt change value of the user channel incoming line is considered a false abrupt change.

[0015] Furthermore, step 3 specifically includes:

[0016] The number of channels with mutations is obtained based on real mutation data. If the number of channels with mutations is less than the total number of user channels, it indicates that the user channel corresponding to the real mutation data has a short circuit fault.

[0017] If the number of channels with a sudden change is equal to the total number of user channels, it indicates that the circuit reference may have changed due to exceeding the sampling range. Therefore, it is necessary to further determine whether there is a short circuit fault in each user channel based on the change in the effective value of the current of the user channel.

[0018] Furthermore, in step 3, if the number of channels with mutations is equal to the total number of user channels, the channel with the earliest mutation time is taken as the first channel, and the mutation duration Tc[k] of the first channel is determined to exceed the time threshold D based on the change in the effective current value of the first channel, where k represents the sequence number of the first channel.

[0019] If yes, it means that the selected real mutation data are all misjudged data caused by exceeding the range; otherwise, it means that there is a short circuit fault in the first channel, and then the other channels are judged to have short circuit faults based on the changes in the effective current values ​​of the other channels.

[0020] Furthermore, the method for determining the mutation duration Tc[k] in step 3 includes:

[0021] If, within the time interval [Ts[k], Ts[k]+D], the effective current value Irms[k] of the first channel is less than the current recovery threshold E, then it means that the abrupt change duration Tc[k] of the first channel does not exceed the time threshold D; otherwise, it means that the abrupt change duration Tc[k] of the first channel exceeds the time threshold D, where Ts[k] represents the abrupt change time of the first channel.

[0022] Furthermore, the method for determining other channel short-circuit faults in step 3 includes:

[0023] Determine whether the difference between the effective current value of other channels before and after the sudden change is less than the current change threshold F. If so, it indicates that the actual sudden change data of the channel is a misjudged data caused by over-range. Otherwise, it indicates that the channel also has a short circuit fault.

[0024] In addition, the present invention provides a meter box-level multi-channel indoor short-circuit fault identification system, including a fault sensing terminal with data acquisition, storage and processing capabilities. The fault sensing terminal is used to identify short-circuit faults according to the above-mentioned meter box-level multi-channel indoor short-circuit fault identification method.

[0025] Furthermore, the fault detection terminal can be any one of the following: meter box-side detection terminal, branch box detection terminal, transformer box detection terminal, or edge-side detection terminal.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0027] 1. If conventional fault identification methods are used, it is necessary to improve the hardware sampling capability (i.e., expand the range to accommodate short-circuit current), which will inevitably increase the cost. However, the present invention does not require changes to the original hardware circuit (no need to change the device range), and can achieve the judgment of large current faults at a lower cost while ensuring the sampling accuracy of small current.

[0028] 2. Through multi-dimensional analysis of existing sampling data, the probability of false or missed fault diagnosis is effectively reduced, and the reliability of indoor short-circuit fault diagnosis is improved.

[0029] 3. High real-time performance; faults can be quickly identified using only a few cycles of sampling data.

[0030] 4. When limited by actual field application conditions, such as when the meter box side equipment does not support or cannot sample the main incoming line, sampling can also be performed through the main station side or the edge side, which has a wide range of applications and greatly improves the accuracy of fault diagnosis. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the short-circuit fault identification method in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the short-circuit fault identification system in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the process of periodically identifying short-circuit faults in an embodiment of the present invention. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described in conjunction with the accompanying drawings, which will more clearly and completely illustrate the technical solution of the present invention.

[0035] like Figure 1 The above describes a method for identifying multi-channel indoor short-circuit faults at the meter box level, as provided in this embodiment, including the following steps:

[0036] 1) Sample the current of the main incoming line of the meter box and the incoming lines of each user channel according to the set sampling period;

[0037] 2) Identify the sudden current changes in the main incoming line of the meter box and the incoming line of the user channel, and record the time of the sudden change;

[0038] 3) Compare the current change times of the main incoming line of the meter box and the incoming line of the user channel to determine whether the current change value of the incoming line of the user channel is the real change data;

[0039] 4) Based on multi-channel mutation analysis, identify real short-circuit data from real mutation data.

[0040] like Figure 2 As shown, in this embodiment, the meter box fault sensing terminal is installed at the meter box. Its main incoming terminal collects the three-phase current after the meter box circuit breaker, and its user incoming terminal collects the incoming current after the user circuit breaker.

[0041] In this embodiment, the steps for short-circuit fault identification are as follows:

[0042] Step 1: The meter box fault detection terminal samples the current of the main incoming line and the incoming lines of each user channel of the meter box at a sampling period of 20ms, and obtains the current sequence I[a]1~I[a]1. n I[b]1~I[b] n I[c]1~I[c] n 、I[1]1~I[1] n ...I[m]1~I[m] n , where n represents the sampling value sequence number, a, b, c represent the current sequence numbers of the three phases ABC of the main incoming line, m represents the user channel sequence number, and m∈[1, number of sampling channels].

[0043] Step 2: Calculate the effective current value Irms[1]~Irms[m] of the user's incoming line for each channel according to the sampling period.

[0044] Step 3: For the current sampling data of each user channel incoming line, calculate the sudden change value ΔI[1]=I[1] of two current points at an interval of t sampling periods. i+t -I[1] i ......ΔI[m]=I[m] i+t -I[m] i , i∈[1,nt].

[0045] Step 4: Compare the mutation values ​​ΔI[1]......ΔI[m] of each channel with the current mutation threshold A one by one. If the mutation value is not less than the current mutation threshold A, record the corresponding time Ts[x] of the mutation point i+t and proceed to step 5 for processing. Here, x represents the channel number where the mutation occurred. Otherwise, it means that the mutation value is misjudged data.

[0046] Step 5: For the current sampling data of the three phases of the main incoming line, calculate the abrupt change value ΔI[a] = I[a] at two current points with an interval of t sampling periods. j+t -I[a] j ΔI[b]=I[b] j+t -I[b] j ΔI[c]=I[c] j+t -I[c] j , j∈[1,nt].

[0047] Step 6: Compare the sudden change values ​​ΔI[a], ΔI[b], and ΔI[c] of the main incoming line with the current sudden change threshold B one by one. If the sudden change value is not less than the current sudden change threshold B, record the corresponding time Ts[y] of the sudden change point j+t, where y represents the phase of the sudden change. By comparing the current sudden change value with the current sudden change thresholds A and B, it is possible to distinguish whether the sudden change is caused by a short circuit or by an impact load, because the sudden change caused by a short circuit is much larger than the sudden change caused by an impact load. At the same time, because the test range of the upstream equipment (i.e., the main incoming line of the meter box) is large, the set threshold B is relatively large, which can accurately exclude the current sudden change caused by the impact load.

[0048] Step 7: Obtain the user channel phase with mutation, and determine whether the corresponding total incoming phase has mutation. If it does not exist, it means that the mutation value is misjudged data. If it exists, further calculate the mutation interval ΔT = \Ts[x] - Ts[y]\.

[0049] If ΔT does not exceed the time threshold C, the corresponding channel mutation value is the real mutation data; otherwise, the corresponding channel mutation value is the misjudged data.

[0050] Step 8: Determine the number of channels with mutations based on the actual mutation data. If the number of channels with mutations is equal to the total number of users, it indicates that the circuit reference may have changed due to exceeding the sampling range, and it is necessary to proceed to Step 9 for processing (determining whether multiple channels are short-circuited at the same time). Otherwise, it indicates that the user channel corresponding to the actual mutation data has a short-circuit fault.

[0051] Step 9: Compare the mutation time Ts[x] of each channel and take the channel with the earliest mutation time (smallest Ts[x]) as the first channel (because there is a current mutation process in a short circuit. When the current does not exceed the sampling range, only the channel where the short circuit actually occurs has a mutation. When it exceeds the range, the reference changes, causing all channel sampling values ​​to be abnormal and exceed the threshold A. Therefore, the first channel that has a short circuit will exceed the threshold A first in the time series).

[0052] Step 10: Based on the effective current value Irms[k] of the first channel, determine whether the abrupt change duration Tc[k] of the first channel exceeds the time threshold D, where k represents the sequence number of the first channel. The determination process specifically includes:

[0053] In each sampling period after the mutation, calculate the effective value of the current Irms[k] of the first channel and determine whether Irms[k] is less than the current recovery threshold E. The termination condition is: 1) Irms[k] of the current period is less than the threshold E or 2) the current time - Ts[x] = Tp exceeds the threshold D.

[0054] If it is case 1), it means that there is a short circuit fault in the first channel. Record the sudden recovery time Te[k] of the first channel, and Tc[k] = Te[k] - Ts[k]. Proceed to step 11 for processing (continue to judge whether there is a short circuit fault in other channels).

[0055] If it is case 2), it means that the mutation duration Tc[k] of the first channel exceeds the threshold D. Therefore, all channels with mutations are misjudged data (because the mutation duration caused by the real fault is very short, the mutation with a duration exceeding the threshold D can only be a misjudgment caused by over-range).

[0056] Step 11: For other channels with sudden changes in time Ts[k] to Te[k], if the difference between the effective value of the current before and after the sudden change (i.e. before and after Ts[k] to Te[k]) is less than the current change threshold F, then the sudden change of the channel is judged to be a misjudgment caused by over-range; otherwise, the current channel is judged to have a short circuit fault at the same time.

[0057] like Figure 3 As shown, for each sampling period, the basic sampling steps are first performed (i.e., the instantaneous current value and the effective value must be collected each time), and then it is determined whether there is a multi-channel mutation marker. If there is, the multi-channel mutation situation is analyzed based on the effective current value. Otherwise, the multi-channel mutation is determined based on the current mutation time of the meter box main line and the user channel line, and the periodic judgment is performed accordingly.

[0058] In other implementations, if some meter box fault sensing terminals do not have the capability to collect data from the main incoming line of the meter box, the collection capabilities of upstream devices (such as branch box sensing terminals, transformer sensing terminals, or edge-side sensing terminals) at branch lines or transformer substations can be utilized. The main station or edge side can then perform further short-circuit fault judgment. Specifically, the main station or edge side records the user short-circuit data Ts[x] reported by the meter box and searches the database for historical data of the upstream device (i.e., the main incoming line of the meter box) corresponding to the short-circuit device based on the existing topology information. The search is conducted to determine whether short-circuit data Ts[y] exists in the upstream device within the allowed time range G. If it does, a true short-circuit fault is identified; otherwise, it is ignored.

[0059] Preferably, based on the actual field test results, t is set to 8, current mutation threshold A is set to 80A, current mutation threshold B is set to 200A, current recovery threshold E is set to 0.1A, current change threshold F is set to 0.5A, time threshold C is set to 60ms, time threshold D is set to 40ms, and allowable time range G is set to 1min.

[0060] The above threshold values ​​are only for preferred implementation cases. For different application scenarios, the threshold parameters can be adjusted or the solutions can be recombined according to the actual situation.

[0061] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications, substitutions, and improvements made by those skilled in the art to the technical solutions of the present invention based on the provided textual description and drawings, without departing from the design concept and spirit of the present invention, should all fall within the scope of protection of the present invention.

Claims

1. A method for identifying multi-channel indoor short-circuit faults at the meter box level, characterized in that, Includes the following steps: Step 1: Obtain the current fluctuation values ​​of the main incoming line of the meter box and the incoming lines of each user channel, and record the fluctuation time; Step 2: Compare the current change times of the main incoming line of the meter box and the incoming lines of each user channel to determine whether the current change value of the user channel incoming line is the real change data. Step 2 specifically includes: If the abrupt change in the corresponding phase of the user channel incoming line and the meter box main incoming line occurs at intervals... ΔT Not exceeding the time threshold C If the current fluctuation value of the user channel incoming line is true, it means that the current fluctuation value of the user channel incoming line is true; otherwise, it means that the current fluctuation value of the user channel incoming line is false. Step 3: Based on multi-channel mutation analysis, identify real short-circuit data from real mutation data; Step 3 specifically includes: The number of channels with mutations is obtained based on real mutation data. If the number of channels with mutations is less than the total number of user channels, it indicates that the user channel corresponding to the real mutation data has a short circuit fault. If the number of channels with abrupt changes is equal to the total number of user channels, then further determine whether there is a short-circuit fault in each user channel based on the change in the effective value of the current of the user channel. In step 3, if the number of channels with sudden changes equals the total number of user channels, then the channel with the earliest sudden change time is selected as the first channel, and the duration of the sudden change in the first channel is determined based on the change in the effective current value of the first channel. Tc[k] Has the time threshold been exceeded? D ,in k Indicates the sequence number of the first channel; If the number of cases exceeds the threshold, it indicates that all the selected real mutation data are misjudged data; otherwise, it indicates that there is a short circuit fault in the first channel. Then, the current effective value changes of other channels are used to determine whether there is a short circuit fault in other channels.

2. The method for identifying meter box-level multi-channel indoor short-circuit faults according to claim 1, characterized in that, Step 1 specifically includes: The current of the main incoming line of the meter box and the incoming lines of each user channel are sampled according to the set sampling period; For the sampling data of each user channel incoming line, calculate the interval respectively. t The sudden change values ​​of two current points in each sampling period are selected, and those values ​​exceeding the current sudden change threshold are filtered out. A The current abrupt change value was recorded, along with its corresponding abrupt change time. Ts[x] ,in x Indicates the channel number where the mutation occurred; For the sampling data of the main incoming line of the meter box, calculate the interval respectively. t The sudden change values ​​of two current points in each sampling period are selected, and those values ​​exceeding the current sudden change threshold are filtered out. B The current abrupt change value was recorded, along with its corresponding abrupt change time. Ts[y] ,in y This indicates the phase in which a sudden change occurs.

3. The method for identifying meter box-level multi-channel indoor short-circuit faults according to claim 1, characterized in that, The duration of mutation in step 3 Tc[k] The methods for determining this include: If in [ Ts[k],Ts[k]+D Within a given time period, the effective value of the current in the first channel exists. Irms[k] Less than the current recovery threshold E This indicates the duration of the mutation in the first channel. Tc[k] Not exceeding the time threshold D Otherwise, it indicates the duration of the mutation in the first channel. Tc[k] Exceeded the time threshold D ,in Ts[k] This indicates the time of abrupt change in the first channel.

4. The method for identifying meter box-level multi-channel indoor short-circuit faults according to claim 1, characterized in that, The methods for determining other channel short-circuit faults in step 3 include: Determine whether the difference between the effective current value of other channels before and after the sudden change is less than the current change threshold F. If so, it indicates that the actual sudden change data of that channel is misjudged data; otherwise, it indicates that there is also a short circuit fault in that channel.

5. A meter box-level multi-channel indoor short-circuit fault identification system, characterized in that, It includes a fault sensing terminal with data acquisition, storage and processing capabilities, the fault sensing terminal being used to identify short circuit faults using the meter box-level multi-channel indoor short circuit fault identification method according to any one of claims 1 to 4.

6. The meter box-level multi-channel indoor short-circuit fault identification system according to claim 5, characterized in that, The fault detection terminal includes any one of the following: meter box-side detection terminal, branch box detection terminal, transformer box detection terminal, or edge-side detection terminal.

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