A residual current synchronous sampling method and device

Abstract

Embodiments of the present application disclose a residual current synchronous sampling method and device; the embodiments of the present application are applied to a master in a power distribution system, and can obtain one-way communication delay time between the master and each slave; target current collection time is determined; for each slave, the target current collection time is subtracted by the one-way communication delay time corresponding to the slave to obtain slave corresponding collection instruction sending time; based on the collection instruction sending time, a current collection instruction is sent to the corresponding slave, and the current collection instruction contains the target current collection time; residual current data synchronously collected and returned by each slave based on the target current collection time is received; vector synthesis is performed based on the residual current data returned by all the slaves to obtain total residual current. Thus, the embodiments of the present application can realize synchronous collection of residual currents of each branch, and improve the accuracy of vector synthesis of total residual current in the power distribution system.

Description

Technical Field

[0001] This application relates to the field of electrical safety monitoring technology, specifically to a method and device for synchronous sampling of residual current. Background Technology

[0002] Residual current refers to the vector sum of the currents in each phase conductor and the neutral line in a low-voltage power distribution system. Its non-zero value usually reflects the existence of leakage to ground and is an important early warning indicator for electrical fires and electric shocks. In multi-branch power distribution scenarios, multiple acquisition units are often deployed to monitor the residual current of each branch, and the data is aggregated and analyzed by a central host to achieve system-level leakage current detection.

[0003] However, existing acquisition methods generally employ polling or asynchronous reporting mechanisms, with the sampling time of each branch triggered instantaneously by the local clock or received command, lacking a unified time reference. Since the residual current is a 50Hz power frequency AC signal, its instantaneous value varies significantly within a cycle, and even a microsecond-level sampling deviation can cause the data from different branches to be in different phases.

[0004] When multiple branches share a neutral wire, theoretically the total residual current should be equal to the vector sum of the residual currents of each branch. However, due to the inability to align the sampling times, the data obtained by the host from each branch are not synchronized. Direct synthesis will introduce a non-negligible phase error, which seriously affects the accuracy of the total residual current calculation, and thus restricts the reliability and sensitivity of the leakage current protection. Summary of the Invention

[0005] This application provides a method and apparatus for synchronous sampling of residual current, which can realize the synchronous acquisition of residual current in each branch, improve the accuracy of vector synthesis of total residual current in the power distribution system, and thus provide support for reliable detection and protection of leakage faults.

[0006] This application provides a residual current synchronous sampling method, applied to a master unit in a power distribution system. The power distribution system also includes multiple slave units, each slave unit being used to collect the residual current of a corresponding branch, and the multiple branches sharing a neutral wire. The method includes:

[0007] Get the one-way communication delay time with each slave device;

[0008] Determine the target current acquisition time;

[0009] For each slave device, the target current acquisition time is subtracted from its corresponding one-way communication delay time to obtain the acquisition command sending time for the slave device.

[0010] Based on the acquisition command sending time, a current acquisition command is sent to the corresponding slave device. The current acquisition command includes the target current acquisition time.

[0011] Receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time;

[0012] The total residual current is obtained by vector synthesis based on the residual current data returned by all slave devices.

[0013] This application embodiment also provides a residual current synchronous sampling device, applied to a master unit in a power distribution system. The power distribution system also includes multiple slave units, each slave unit being used to collect the residual current of a corresponding branch, and the multiple branches sharing a neutral wire. The device includes:

[0014] The delay time acquisition unit is used to acquire the one-way communication delay time with each slave device;

[0015] The acquisition time determination unit is used to determine the target current acquisition time;

[0016] The transmission time determination unit is used to subtract the corresponding one-way communication delay time from the target current acquisition time for each slave device to obtain the acquisition command transmission time corresponding to the slave device.

[0017] The instruction sending unit is used to send a current acquisition instruction to the corresponding slave device based on the acquisition instruction sending time. The current acquisition instruction includes the target current acquisition time.

[0018] The current data receiving unit is used to receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time;

[0019] The vector synthesis unit is used to perform vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current.

[0020] In some embodiments, before obtaining the one-way communication delay time with each slave, the method further includes:

[0021] Send synchronization requests to multiple slave devices respectively;

[0022] Receive confirmation responses from each slave device based on the synchronization request;

[0023] Obtain the preset request response time for each slave device. The request response time represents the internal processing delay experienced by the corresponding slave device after receiving the synchronization request and before issuing an acknowledgment response.

[0024] For each slave device, the one-way communication delay time is determined based on the reception time of the acknowledgment response, the sending time of the synchronization request, and the slave device's request response time.

[0025] In some embodiments, the one-way communication delay time corresponding to the slave device is determined based on the reception time of the acknowledgment response, the transmission time of the synchronization request, and the slave device's request response time, including:

[0026] Subtract the time of sending the synchronization request from the time of receiving the confirmation response to obtain the first difference;

[0027] Subtract the slave's request response time from the first difference to obtain the second difference;

[0028] Divide the second difference by 2 to obtain the one-way communication delay time corresponding to the slave device.

[0029] In some embodiments, before obtaining the preset request response time of each slave device, the method further includes:

[0030] After configuring the communication interface between each slave device and the master device to zero propagation delay mode, a test synchronization request is sent to each of the multiple slave devices.

[0031] Receive test confirmation responses from each slave device based on the test synchronization request;

[0032] For each slave device, the corresponding request response time is determined based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response.

[0033] In some embodiments, it also includes:

[0034] Perform validity verification on the request response time corresponding to the slave device;

[0035] If the request response time exceeds the preset reasonable range, it is determined that the request response time of the corresponding slave is abnormal, and the process returns to the steps of configuring the communication interface between each slave and the master to zero propagation delay mode, sending test synchronization requests to multiple slaves respectively; receiving test confirmation responses returned by each slave based on the test synchronization requests; and determining the corresponding request response time for each slave based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response, so as to obtain the updated request response time.

[0036] In some embodiments, after performing vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current, the method further includes:

[0037] The total residual current is compared with a preset first leakage current threshold.

[0038] When the total residual current is greater than or equal to the first leakage current threshold, a leakage current fault is determined to have occurred in the power distribution system.

[0039] In some embodiments, after determining that a leakage fault has occurred in the power distribution system when the total residual current is greater than or equal to a first leakage current threshold, the method further includes:

[0040] The residual current data returned by each slave device is compared with the preset second leakage threshold to determine whether there is a target branch that exceeds the second leakage threshold.

[0041] When a leakage fault is detected and a target branch exists, the leakage protection action for the target branch is triggered.

[0042] In some embodiments, triggering a leakage current protection action for the target branch includes:

[0043] Send a trip control signal to the circuit breaker of the power distribution system to cut off the power supply to the target branch;

[0044] And / or generate leakage current alarm information containing the target branch identifier, and upload it to the monitoring platform through the communication interface.

[0045] In some embodiments, determining the target current acquisition time includes:

[0046] Obtain the grid frequency of the power distribution system and calculate the current signal period based on the grid frequency;

[0047] Based on the current system time, the smallest time point that is no earlier than the current system time and is an integer multiple of the current signal period is taken as the target current acquisition time.

[0048] This application also provides an electronic device, including a processor and a memory, wherein the memory stores multiple instructions; the processor loads instructions from the memory to execute the steps in any of the residual current synchronous sampling methods provided in this application.

[0049] This application also provides a computer-readable storage medium storing multiple instructions adapted for loading by a processor to execute steps in any of the residual current synchronous sampling methods provided in this application.

[0050] This application also provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the steps in any of the residual current synchronous sampling methods provided in this application.

[0051] In this application, the power distribution system includes a master unit and multiple slave units. Each slave unit is used to collect the residual current of its connected branch, and the multiple branches share a neutral wire. The master unit first obtains the one-way communication delay time with each slave unit and determines a target current acquisition time. Then, for each slave unit, the master unit subtracts its corresponding one-way communication delay time from the target current acquisition time to obtain the acquisition command sending time for that slave unit. When the acquisition command sending time is reached, the master unit sends a current acquisition command containing the target current acquisition time to the corresponding slave unit. After receiving the current acquisition command, each slave unit synchronously performs residual current acquisition locally according to the target current acquisition time and returns the acquired residual current data to the master unit. The master unit receives the residual current data returned by all slave units based on the same target current acquisition time and performs vector synthesis to obtain the total residual current. Thus, even if the communication paths of each slave unit are different, high-precision synchronous acquisition of residual current of multiple branches can still be achieved, improving the accuracy of total residual current vector synthesis in the power distribution system, thereby providing support for reliable detection and protection of leakage faults. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a flowchart illustrating a residual current synchronous sampling method provided in an embodiment of this application;

[0054] Figure 2 This is a schematic diagram of the structure of a residual current synchronous sampling device provided in an embodiment of this application. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] This application provides a method and apparatus for synchronous sampling of residual current.

[0057] Specifically, the residual current synchronous sampling device can be integrated into an electronic device, such as a terminal or server. The terminal can be a mobile phone, tablet, smart Bluetooth device, laptop, or personal computer (PC); the server can be a single server or a server cluster consisting of multiple servers.

[0058] In some embodiments, the residual current synchronous sampling device can also be integrated into multiple electronic devices. For example, the residual current synchronous sampling device can be integrated into multiple servers, and the residual current synchronous sampling method of this application can be implemented by multiple servers.

[0059] In some embodiments, the server may also be implemented as a terminal.

[0060] The following sections provide detailed descriptions of each example. It should be noted that the sequence numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0061] In this embodiment, a residual current synchronous sampling method is provided, applied to the master unit in a power distribution system. The power distribution system also includes multiple slave units, each slave unit being used to collect the residual current of its corresponding branch, and the multiple branches sharing a neutral wire, such as... Figure 1 The specific process of this residual current synchronous sampling method can be shown as follows:

[0062] Among them, the power distribution system refers to the low-voltage power network used to distribute electrical energy to electrical equipment. It typically includes power sources, main lines, multiple branch circuits (branch lines), protection devices, and monitoring units, and is suitable for residential, commercial, or industrial scenarios.

[0063] The host refers to the central control unit in the power distribution system. It is located on the main control side and is used to coordinate the slave units, send acquisition commands, receive data, and perform total residual current synthesis and leakage current judgment.

[0064] The slave unit refers to the local monitoring unit deployed on each branch, which has residual current sensing, data processing and communication functions, responds to the host command and collects the residual current of the branch at a specified time.

[0065] A branch circuit refers to an independent electrical circuit that originates from the distribution bus, such as a lighting circuit, socket circuit, or power circuit. Each branch circuit connects to one or more loads.

[0066] Residual current refers to the vector sum of the currents flowing through the phase line and the neutral line (zero line) in a branch circuit. Under normal circumstances, it should be zero. When there is leakage to ground (such as insulation fault or electric shock), this value is non-zero, and its magnitude reflects the degree of leakage.

[0067] The neutral line, also known as the neutral wire, is used in multi-branch power distribution systems. Multiple branches share the same neutral line to return to the power source, forming a common neutral line topology. Under this architecture, the total residual current of the system is theoretically equal to the vector sum of the residual currents of each branch.

[0068] 101. Obtain the one-way communication delay time with each slave device.

[0069] One-way communication delay time refers to the propagation delay in the communication link after the communication command is issued by the host and before it reaches the corresponding slave. The communication command can be a control message used to coordinate the sampling timing, such as a synchronization request or a current acquisition command. The communication link can be understood as the physical transmission medium and communication interface connecting the host and the slave, such as an industrial communication channel such as an RS485 bus, a CAN bus, or an Ethernet bus.

[0070] In some embodiments, the one-way communication delay time of each slave device can be independently measured to achieve differentiated delay compensation. Before obtaining the one-way communication delay time with each slave device, the method further includes:

[0071] Send synchronization requests to multiple slave devices respectively;

[0072] Receive confirmation responses from each slave device based on the synchronization request;

[0073] Obtain the preset request response time for each slave device. The request response time represents the internal processing delay experienced by the corresponding slave device after receiving the synchronization request and before issuing an acknowledgment response.

[0074] For each slave device, the one-way communication delay time is determined based on the reception time of the acknowledgment response, the sending time of the synchronization request, and the slave device's request response time.

[0075] The synchronization request is a control command actively sent by the host to the slave to initiate the communication delay calibration process, which triggers the slave's response process.

[0076] The acknowledgment response is a response message generated by the slave device after receiving the synchronization request, according to preset logic, and returned to the master device. It usually includes the slave device identifier and the local processing completion status.

[0077] Request response time refers to the internal processing delay consumed by the slave device from receiving the synchronization request to starting to send the acknowledgment response. This parameter reflects the inherent response characteristics of the slave device's hardware and software stack and is usually calibrated and pre-stored during the system initialization phase.

[0078] Internal processing latency generally refers to the time required for the slave device to perform operations such as protocol parsing, task scheduling, and data preparation after receiving external instructions, excluding the signal transmission time in the communication link.

[0079] One-way communication latency refers to the pure transmission delay experienced by the synchronization request from the host to the corresponding slave in the communication link, excluding the slave's internal processing delay.

[0080] In some embodiments, the synchronization request employs a simplified handshake mechanism: the host sends a control frame containing a synchronization request identifier (SYN), and the slave returns a response frame containing an acknowledgment identifier (ACK), which is used to complete the communication delay calibration interaction process.

[0081] In some embodiments, the one-way propagation delay required for transmitting commands on the communication link between the master and slave devices can be accurately calculated, effectively separating the transmission delay of the communication link itself from the processing delay inside the slave device. This provides a high-precision delay compensation basis for subsequent synchronous sampling, significantly improving the synchronization of multi-slave residual current acquisition and the accuracy of total residual current vector synthesis. Based on the reception time of the acknowledgment response, the transmission time of the synchronization request, and the slave device's request response time, the one-way communication delay time corresponding to the slave device is determined, including:

[0082] Subtract the time of sending the synchronization request from the time of receiving the confirmation response to obtain the first difference;

[0083] Subtract the slave's request response time from the first difference to obtain the second difference;

[0084] Divide the second difference by 2 to obtain the one-way communication delay time corresponding to the slave device.

[0085] The confirmation response reception time refers to the local system timestamp of the synchronization request message sent by the host to the target slave, which is recorded by the host when sending the instruction.

[0086] The time of sending a synchronization request refers to the local system timestamp when the host receives the acknowledgment response message returned by the slave, which is recorded by the host when the reception is interrupted or when a response is detected by polling.

[0087] The first difference represents the total round-trip time (RTT) between the host sending a synchronization request and receiving an acknowledgment response. It includes the transmission delay of the signal in both the host-to-slave and slave-to-host directions, as well as the delay introduced by the slave's internal processing.

[0088] The second difference represents the pure bidirectional communication propagation time after removing the internal processing delay of the slave device (i.e., request-response time). Its value is equal to the sum of the round-trip link transmission delays and is used to further derive the unidirectional delay.

[0089] One-way communication delay time ,in, This is the confirmation response reception time. It is the time when the synchronization request was sent. This is the slave device's request response time.

[0090] In some embodiments, the internal processing latency of each slave device caused by hardware performance, software scheduling, or firmware differences can be measured individually and independently, thereby providing accurate request response time parameters for subsequent communication delay calibration, effectively improving the accuracy of unidirectional communication delay calculation, and thus ensuring the synchronization of residual current sampling across multiple branches. Before obtaining the preset request response time for each slave device, the method further includes:

[0091] After configuring the communication interface between each slave device and the master device to zero propagation delay mode, a test synchronization request is sent to each of the multiple slave devices.

[0092] Receive test confirmation responses from each slave device based on the test synchronization request;

[0093] For each slave device, the corresponding request response time is determined based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response.

[0094] The communication interface refers to the physical and protocol layer connection unit used for data exchange between the master and slave devices, including but not limited to industrial communication hardware interfaces such as RS-485 interface, Controller Area Network (CAN) bus, Ethernet interface or Universal Asynchronous Receiver / Transmitter (UART) and their driving logic.

[0095] Zero propagation delay mode refers to the physical or logical direct connection of the communication interface through shorting, loopback, or local loopback, thereby eliminating the transmission delay of the signal in the external link. This allows the data sent by the host to be received by the slave (or simulated slave) almost instantaneously, or vice versa. In this mode, the measured time difference mainly reflects the internal processing overhead of the device.

[0096] The test synchronization request is a dedicated control message sent by the host during the calibration phase to trigger the slave to execute the response process. Its format is similar to that of the formal synchronization request, but it is only used to measure the response time.

[0097] The test confirmation response is a response message generated and returned by the slave device according to a preset protocol after receiving the test synchronization request. It is used to cooperate with the host to complete the calculation of the request response time.

[0098] The time when the test synchronization request is sent is the local system timestamp recorded when the host sends the test synchronization request.

[0099] The time of receiving the test confirmation response is the local system timestamp recorded when the host receives the corresponding test confirmation response.

[0100] In some embodiments, the zero propagation delay mode can be enabled during the system installation and commissioning phase or maintenance window, and the communication interface can be configured to enter a local loopback state through software configuration without the need for physical rewiring.

[0101] In some embodiments, the request response time is an inherent parameter of the slave device, determined by the manufacturer through a standard testing process before shipment, and stored in the slave device's non-volatile memory.

[0102] It is understandable that the response time for the slave device's request is... It is pre-calibrated at the factory; after the program is compiled, the instructions to be executed are fixed, and it can be calculated. The host sends a synchronization pulse (i.e., a test synchronization request), and the slave receives the synchronization pulse and sends a pulse back to the host (i.e., a test confirmation response). This refers to the CPU time it takes for the slave device to receive a pulse and then return it to the master device. This time is the sum of the number of instruction clock cycles executed by the slave device. The number of instruction clock cycles can be given in the processor manual, and the request response time can be calculated from this. .

[0103] In some embodiments, the device possesses self-diagnostic and self-correcting capabilities, dynamically maintaining the validity of each slave delay parameter, significantly improving the robustness of residual current synchronous sampling and the reliability of total residual current synthesis under long-term operation, and further includes:

[0104] Perform validity verification on the request response time corresponding to the slave device;

[0105] If the request response time exceeds the preset reasonable range, it is determined that the request response time of the corresponding slave is abnormal, and the process returns to the steps of configuring the communication interface between each slave and the master to zero propagation delay mode, sending test synchronization requests to multiple slaves respectively; receiving test confirmation responses returned by each slave based on the test synchronization requests; and determining the corresponding request response time for each slave based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response, so as to obtain the updated request response time.

[0106] Among them, validity verification refers to the process by which the host judges the reasonableness of the request response time that has been acquired or pre-stored. This is usually achieved by comparing whether it falls within the expected value range, in order to eliminate abnormal values ​​caused by storage errors, device drift or environmental interference.

[0107] The preset reasonable range refers to the allowable fluctuation range of request response time set based on the slave hardware platform, software architecture and historical test data, such as 50 μs to 300 μs; this range can be configured during system initialization or fixed by the manufacturer in the host configuration file.

[0108] An abnormal request response time indicates that the request response time currently used by a slave device exceeds the preset reasonable range, suggesting that it may no longer accurately reflect the actual internal processing latency of the slave device and needs to be recalibrated.

[0109] The updated request response time refers to the new request response time value obtained by re-executing the test process in zero propagation delay mode after an anomaly is detected. This new value replaces the original anomaly value and ensures the accuracy of subsequent one-way communication delay calculations.

[0110] Understandably, the self-calibration mechanism can be triggered during system power-on initialization, periodic maintenance cycles, or when a synchronization anomaly is detected, thereby ensuring that the request response time always reflects the current actual processing performance of the slave device and avoiding the impact of time delay deviations caused by device aging, temperature drift, or firmware upgrades on synchronization accuracy.

[0111] In some embodiments, after the station AC residual current monitoring system is installed in the power distribution system, the first step is to calibrate the synchronization delay between the slave and the master. When the master and a slave in the system enter the synchronization calibration mode, the master and slave complete the synchronization calibration, and other slaves do not participate in the calibration.

[0112] 102. Determine the target current acquisition time.

[0113] The target current acquisition time refers to a specific future moment uniformly designated by the host to achieve synchronous sampling of the residual current of multiple slave devices. Each slave device needs to sample the residual current of its branch at this time. This time is usually aligned with the periodic phase of the power frequency current signal (such as zero-crossing or peak point) to ensure that the acquired instantaneous values ​​are comparable and that vector synthesis is effective.

[0114] In some embodiments, to ensure that the sampling time of the residual current in each branch is aligned with the fixed electrical angle (e.g., zero crossing) of the power frequency signal, thereby avoiding vector synthesis errors caused by phase deviation, the target current acquisition time is determined, including:

[0115] Obtain the grid frequency of the power distribution system and calculate the current signal period based on the grid frequency;

[0116] Based on the current system time, the smallest time point that is no earlier than the current system time and is an integer multiple of the current signal period is taken as the target current acquisition time.

[0117] Among them, the grid frequency refers to the fundamental frequency of AC voltage or current in the power distribution system, which is usually 50Hz or 60Hz, etc., and is the basic parameter that determines the period of the current signal.

[0118] The current signal period refers to the time required for the residual current to complete a full sine wave, and its value is equal to the reciprocal of the power grid frequency (for example, 50 Hz corresponds to a period of 20 ms).

[0119] The current system time refers to the real-time timestamp read by the host's local high-precision clock when performing sampling scheduling, which serves as the starting reference point for calculating the target acquisition time.

[0120] The target current acquisition time refers to the future time uniformly specified by the host to trigger synchronous sampling of all slave devices. This time is constrained to an integer multiple of the current signal period to ensure that the sampled values ​​of each branch are at the same electrical angle, thus ensuring the accuracy of subsequent vector synthesis.

[0121] Understandably, determining the target current acquisition time allows multiple slave devices to complete sampling at the same power frequency phase point, effectively eliminating phase mismatch problems caused by periodic fluctuations in the power grid or random sampling, and significantly improving the accuracy of total residual current calculation and the reliability of leakage current judgment.

[0122] 103. For each slave device, subtract its corresponding one-way communication delay time from the target current acquisition time to obtain the acquisition command sending time for the slave device.

[0123] The acquisition command sending time refers to the specific moment when the host sends a current acquisition command to a slave device. This moment is calculated by subtracting the one-way communication delay time of the slave device from the unified target current acquisition time, so as to ensure that the command arrives at the slave device exactly at the target current acquisition time after being transmitted through the communication link, thereby triggering its synchronous sampling.

[0124] 104. Based on the acquisition command sending time, send a current acquisition command to the corresponding slave device. The current acquisition command includes the target current acquisition time.

[0125] The current acquisition instruction refers to the control message generated by the host and sent to the slave, which instructs the slave to perform the remaining current sampling operation at the specified target current acquisition time. The instruction includes at least the target current acquisition time, the slave address and verification information. After receiving the instruction, the slave stores it in the local timer or scheduling queue and triggers the analog-to-digital converter (ADC) to perform synchronous sampling when the target time is reached.

[0126] Understandably, the current acquisition command does not require the slave devices to "sample immediately," but rather serves as a time-stamped delayed execution command, enabling each slave device to complete sampling at a unified future moment—the target current acquisition time—thus achieving physical phase alignment of the residual currents across multiple branches. This "command pre-issuance + timed execution" mechanism is key to solving the problem of sampling synchronization failure caused by communication delays and is also the foundation for achieving high-precision vector synthesis.

[0127] 105. Receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time.

[0128] The residual current data refers to the instantaneous value of the residual current or its digital representation obtained by each slave device in its corresponding branch at the target current acquisition time specified by the host. It usually includes the current amplitude, sampling timestamp and slave device identification information, which are used by the host for subsequent vector synthesis and leakage current analysis.

[0129] 106. Perform vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current.

[0130] Among them, the total residual current refers to the vector sum of the residual currents of all common neutral line branches in the power distribution system at the same moment (i.e., the target current acquisition time). Its physical meaning is the actual ground leakage current flowing through the main neutral line of the system. This value reflects the comprehensive leakage current status of the entire power distribution system and is the core basis for judging whether there is a system-level leakage current fault.

[0131] Vector synthesis refers to the algebraic addition of the instantaneous values ​​of the residual current in each branch according to the same time base (theoretically, it is a scalar sum because they share a common zero line, but because the phase needs to be synchronized, it is called vector synthesis).

[0132] In some embodiments, to achieve real-time monitoring and risk warning of the overall insulation status of the power distribution system, after vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current, the method further includes:

[0133] The total residual current is compared with a preset first leakage current threshold.

[0134] When the total residual current is greater than or equal to the first leakage current threshold, a leakage current fault is determined to have occurred in the power distribution system.

[0135] The first leakage threshold is a preset current limit used to determine whether there is an overall leakage risk in the power distribution system. It is usually set according to national electrical safety standards and system load characteristics, with a typical value range of 30mA to 300mA. This threshold is stored in the host configuration parameters and serves as the triggering reference for system-level leakage protection.

[0136] A leakage fault refers to an abnormal ground leakage current in a power distribution system caused by factors such as equipment insulation deterioration, line damage, humid environment, or electric shock, and the total residual current reaches or exceeds the safety limit. This fault may cause electrical fires, equipment damage, or personal safety accidents, and requires timely alarm or power disconnection.

[0137] In some embodiments, to further achieve fault location and selective protection, and to avoid false disconnection of non-faulty branches due to system-level leakage current alarms, after determining that a leakage current fault has occurred in the power distribution system when the total residual current is greater than or equal to a first leakage current threshold, the method further includes:

[0138] The residual current data returned by each slave device is compared with the preset second leakage threshold to determine whether there is a target branch that exceeds the second leakage threshold.

[0139] When a leakage fault is detected and a target branch exists, the leakage protection action for the target branch is triggered.

[0140] The second leakage threshold is a preset current limit used to determine whether there is a risk of local leakage in a single branch. It is usually lower than or equal to the first leakage threshold, with a typical range of 10mA to 300mA. It can be configured differently according to the branch load type (such as lighting, sockets, motors). Its function is to identify specific fault circuits and support refined protection.

[0141] The target branch refers to the branch whose residual current data is greater than or equal to the second leakage threshold in the current sampling period, which is the circuit to be processed that may have insulation faults or abnormal leakage.

[0142] The leakage current protection action refers to the safety response measures performed on the target branch, including but not limited to: sending a trip control signal to the circuit breaker or relay of the corresponding branch to cut off the power supply, and / or generating leakage current alarm information containing branch identification, current value and timestamp, and uploading it to the local monitoring unit or remote platform through the communication interface.

[0143] Understandably, the second leakage threshold can be configured differently according to the load characteristics, power usage scenarios, or safety levels of each branch. This allows the system to accurately identify the local circuits where the actual abnormality occurs, provided that the overall system is confirmed to have leakage risk. This achieves a two-level leakage protection strategy of "first judging the system risk, then locating the source of the fault," effectively balancing safety and power supply continuity.

[0144] In some embodiments, to achieve rapid isolation of faulty circuits and provide remote operation and maintenance support, triggering leakage current protection action for the target branch includes:

[0145] Send a trip control signal to the circuit breaker of the power distribution system to cut off the power supply to the target branch;

[0146] And / or generate leakage current alarm information containing the target branch identifier, and upload it to the monitoring platform through the communication interface.

[0147] Among them, circuit breakers refer to automatic protection switching devices installed on target branches, which have overload, short circuit and leakage protection functions. They can automatically disconnect the circuit when receiving external control signals or detecting abnormal current. Typical types include miniature circuit breakers (MCB), residual current operated circuit breakers (RCBO) or smart circuit breakers.

[0148] The trip control signal refers to the electrical or digital command issued by the host to force the circuit breaker to perform the tripping operation. It can be transmitted through relay contacts, dry contact outputs or communication buses (such as Modbus). Its function is to actively cut off the power supply of the target branch to eliminate the risk of leakage.

[0149] The target branch identifier is used to uniquely identify the information of the branch where the leakage abnormality has occurred, such as the branch number, slave address, physical location code or circuit name, to ensure that alarm and control actions can be accurately matched to the specific power circuit.

[0150] Leakage alarm information refers to a data message containing key parameters of a leakage event, including at least the target branch identifier, residual current value, occurrence time, and fault type (such as "branch overcurrent" or "insulation degradation"), which is used for recording, displaying, or further analysis.

[0151] The communication interface refers to the hardware and protocol unit that enables the host to exchange data with external systems, including but not limited to RS485, CAN, Ethernet, Wi-Fi or 4G modules, which support the reliable uploading of alarm information.

[0152] A monitoring platform refers to a local or cloud-based power distribution monitoring system used to receive, store, and display alarm information, and can provide a human-machine interface for operation and maintenance personnel to view fault details, confirm the handling status, or remotely reset equipment.

[0153] It is understandable that the leakage protection action adopts a dual mechanism of "local disconnection + remote alarm". It can isolate the faulty branch in milliseconds to ensure the safety of personnel and equipment, and provide maintenance personnel with accurate fault location basis through structured alarm information, avoiding blind troubleshooting. Thus, while improving safety, it significantly enhances the maintainability and intelligent management level of the power distribution system.

[0154] To better implement the above methods, this application also provides a residual current synchronous sampling device, which can be integrated into an electronic device, such as a terminal or server. The terminal can be a mobile phone, tablet computer, smart Bluetooth device, laptop computer, or personal computer; the server can be a single server or a server cluster composed of multiple servers.

[0155] For example, in this embodiment, a residual current synchronous sampling device is applied to the host of the power distribution system. The power distribution system also includes multiple slave devices, each of which is used to collect the residual current of the corresponding branch. The multiple branches share a neutral wire. Taking the integration of the device into an electronic device as an example, the method of this application embodiment will be described in detail.

[0156] For example, such as Figure 2As shown, the residual current synchronous sampling device may include a delay time acquisition unit 201, a sampling time determination unit 202, a transmission time determination unit 203, a command transmission unit 204, a current data receiving unit 205, and a vector synthesis unit 206, as follows:

[0157] (a) Delay time acquisition unit 201.

[0158] The delay time acquisition unit 201 is used to acquire the one-way communication delay time with each slave device.

[0159] In some embodiments, before obtaining the one-way communication delay time with each slave, the method further includes:

[0160] Send synchronization requests to multiple slave devices respectively;

[0161] Receive confirmation responses from each slave device based on the synchronization request;

[0162] Obtain the preset request response time for each slave device. The request response time represents the internal processing delay experienced by the corresponding slave device after receiving the synchronization request and before issuing an acknowledgment response.

[0163] For each slave device, the one-way communication delay time is determined based on the reception time of the acknowledgment response, the sending time of the synchronization request, and the slave device's request response time.

[0164] In some embodiments, the one-way communication delay time corresponding to the slave device is determined based on the reception time of the acknowledgment response, the transmission time of the synchronization request, and the slave device's request response time, including:

[0165] Subtract the time of sending the synchronization request from the time of receiving the confirmation response to obtain the first difference;

[0166] Subtract the slave's request response time from the first difference to obtain the second difference;

[0167] Divide the second difference by 2 to obtain the one-way communication delay time corresponding to the slave device.

[0168] In some embodiments, before obtaining the preset request response time of each slave device, the method further includes:

[0169] After configuring the communication interface between each slave device and the master device to zero propagation delay mode, a test synchronization request is sent to each of the multiple slave devices.

[0170] Receive test confirmation responses from each slave device based on the test synchronization request;

[0171] For each slave device, the corresponding request response time is determined based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response.

[0172] In some embodiments, it also includes:

[0173] Perform validity verification on the request response time corresponding to the slave device;

[0174] If the request response time exceeds the preset reasonable range, it is determined that the request response time of the corresponding slave is abnormal, and the process returns to the steps of configuring the communication interface between each slave and the master to zero propagation delay mode, sending test synchronization requests to multiple slaves respectively; receiving test confirmation responses returned by each slave based on the test synchronization requests; and determining the corresponding request response time for each slave based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response, so as to obtain the updated request response time.

[0175] (II) Unit 202 for determining the collection time.

[0176] The acquisition time determination unit 202 is used to determine the target current acquisition time.

[0177] In some embodiments, determining the target current acquisition time includes:

[0178] Obtain the grid frequency of the power distribution system and calculate the current signal period based on the grid frequency;

[0179] Based on the current system time, the smallest time point that is no earlier than the current system time and is an integer multiple of the current signal period is taken as the target current acquisition time.

[0180] (III) Sending time determination unit 203.

[0181] The transmission time determination unit 203 is used to subtract the corresponding one-way communication delay time from the target current acquisition time for each slave device to obtain the acquisition command transmission time corresponding to the slave device.

[0182] (iv) Instruction sending unit 204.

[0183] The instruction sending unit 204 is used to send a current acquisition instruction to the corresponding slave device based on the acquisition instruction sending time. The current acquisition instruction includes the target current acquisition time.

[0184] (v) Current data receiving unit 205.

[0185] The current data receiving unit 205 is used to receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time.

[0186] (vi) Vector synthesis unit 206.

[0187] Vector synthesis unit 206 is used to perform vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current.

[0188] In some embodiments, after performing vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current, the method further includes:

[0189] The total residual current is compared with a preset first leakage current threshold.

[0190] When the total residual current is greater than or equal to the first leakage current threshold, a leakage current fault is determined to have occurred in the power distribution system.

[0191] In some embodiments, after determining that a leakage fault has occurred in the power distribution system when the total residual current is greater than or equal to a first leakage current threshold, the method further includes:

[0192] The residual current data returned by each slave device is compared with the preset second leakage threshold to determine whether there is a target branch that exceeds the second leakage threshold.

[0193] When a leakage fault is detected and a target branch exists, the leakage protection action for the target branch is triggered.

[0194] In some embodiments, triggering a leakage current protection action for the target branch includes:

[0195] Send a trip control signal to the circuit breaker of the power distribution system to cut off the power supply to the target branch;

[0196] And / or generate leakage current alarm information containing the target branch identifier, and upload it to the monitoring platform through the communication interface.

[0197] In practice, each of the above units can be implemented as an independent entity or can be arbitrarily combined to be implemented as the same or several entities. For the specific implementation of each of the above units, please refer to the previous method embodiments, which will not be repeated here.

[0198] Therefore, the embodiments of this application can realize the synchronous acquisition of residual current in each branch, improve the accuracy of the vector synthesis of total residual current in the power distribution system, and thus provide support for reliable detection and protection of leakage faults.

[0199] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0200] Therefore, embodiments of this application provide a computer-readable storage medium storing a plurality of instructions that can be loaded by a processor to execute steps in any of the residual current synchronous sampling methods provided in embodiments of this application.

[0201] The storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0202] Since the instructions stored in the storage medium can execute the steps of any of the residual current synchronous sampling methods provided in the embodiments of this application, the beneficial effects that any of the residual current synchronous sampling methods provided in the embodiments of this application can achieve can be realized. For details, please refer to the previous embodiments, which will not be repeated here.

[0203] According to one aspect of this application, a computer program product or computer program is provided, comprising a computer program / instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer program / instructions from the computer-readable storage medium and executes the computer program / instructions, causing the electronic device to perform the method provided in the residual current synchronous sampling aspect of the above embodiments.

[0204] The foregoing has provided a detailed description of a residual current synchronous sampling method and apparatus provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for synchronous sampling of residual current, characterized in that, A master unit applied in a power distribution system, wherein the power distribution system further includes multiple slave units, each slave unit being used to collect the residual current of a corresponding branch, and the multiple branches sharing a neutral wire, the method comprising: Get the one-way communication delay time with each slave device; Determine the target current acquisition time; For each slave device, the target current acquisition time is subtracted from its corresponding one-way communication delay time to obtain the acquisition command transmission time for that slave device. Based on the acquisition instruction sending time, a current acquisition instruction is sent to the corresponding slave device, the current acquisition instruction including the target current acquisition time; Receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time; The total residual current is obtained by vector synthesis based on the residual current data returned by all slave devices.

2. The method as described in claim 1, characterized in that, Before obtaining the one-way communication delay time with each slave device, the method further includes: Send synchronization requests to the plurality of slave devices respectively; Receive an acknowledgment response from each slave device based on the synchronization request; Obtain the preset request response time for each slave device, where the request response time represents the internal processing delay experienced by the corresponding slave device after receiving the synchronization request and before issuing an acknowledgment response; For each slave device, the one-way communication delay time corresponding to the slave device is determined based on the reception time of the acknowledgment response, the sending time of the synchronization request, and the request response time of the slave device.

3. The method as described in claim 2, characterized in that, The step of determining the one-way communication delay time corresponding to the slave device based on the reception time of the acknowledgment response, the sending time of the synchronization request, and the request response time of the slave device includes: Subtract the time of sending the synchronization request from the time of receiving the confirmation response to obtain the first difference; Subtract the slave device's request response time from the first difference to obtain the second difference; Divide the second difference by 2 to obtain the one-way communication delay time corresponding to the slave device.

4. The method as described in claim 2, characterized in that, Before obtaining the preset request response time for each slave device, the method further includes: After configuring the communication interface between each slave device and the master device to zero propagation delay mode, a test synchronization request is sent to each of the multiple slave devices. Receive test confirmation responses from each slave device based on the test synchronization request; For each slave device, the request response time corresponding to the slave device is determined based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response.

5. The method as described in claim 4, characterized in that, Also includes: The validity of the request response time corresponding to the slave device is verified; If the request response time exceeds the preset reasonable range, it is determined that the request response time of the corresponding slave is abnormal, and the process returns to the step of configuring the communication interface between each slave and the master to zero propagation delay mode, sending test synchronization requests to each of the multiple slaves respectively, and receiving test confirmation responses returned by each slave based on the test synchronization requests. For each slave device, the step of determining the corresponding request response time of the slave device based on the difference between the sending time of the test synchronization request and the receiving time of the corresponding test confirmation response is used to obtain the updated request response time.

6. The method as described in claim 1, characterized in that, After performing vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current, the process further includes: The total residual current is compared with a preset first leakage current threshold. If the total residual current is greater than or equal to the first leakage threshold, then a leakage fault is determined to have occurred in the power distribution system.

7. The method as described in claim 6, characterized in that, After determining that a leakage fault has occurred in the power distribution system when the total residual current is greater than or equal to the first leakage threshold, the method further includes: The residual current data returned by each slave device is compared with the preset second leakage threshold to determine whether there is a target branch that exceeds the second leakage threshold. When a leakage fault is detected and the target branch exists, the leakage protection action for the target branch is triggered.

8. The method as described in claim 7, characterized in that, The triggering of the leakage protection action for the target branch includes: Send a trip control signal to the circuit breaker of the power distribution system to cut off the power supply to the target branch; And / or generate leakage current alarm information containing the target branch identifier, and upload it to the monitoring platform through the communication interface.

9. The method as described in claim 1, characterized in that, The determination of the target current acquisition time includes: Obtain the grid frequency of the power distribution system and calculate the current signal period based on the grid frequency; Based on the current system time, the smallest time point that is no earlier than the current system time and is an integer multiple of the current signal period is taken as the target current acquisition time.

10. A residual current synchronous sampling device, characterized in that, A master unit used in a power distribution system, wherein the power distribution system also includes multiple slave units, each slave unit is used to collect the residual current of a corresponding branch, and the multiple branches share a neutral wire, the device comprising: The delay time acquisition unit is used to acquire the one-way communication delay time with each slave device; The acquisition time determination unit is used to determine the target current acquisition time; The transmission time determination unit is used to subtract the corresponding one-way communication delay time from the target current acquisition time for each slave device to obtain the acquisition command transmission time corresponding to the slave device. The instruction sending unit is used to send a current acquisition instruction to the corresponding slave device based on the acquisition instruction sending time, wherein the current acquisition instruction includes the target current acquisition time; The current data receiving unit is used to receive the remaining current data synchronously collected and returned by each slave device based on the target current acquisition time; The vector synthesis unit is used to perform vector synthesis based on the residual current data returned by all slave devices to obtain the total residual current.

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