Communication-based status check device for DC ground fault detection device

Abstract

The present invention relates to a communication-based status check device for a DC ground fault detection device, and more specifically, to a communication-based status check device for a DC ground fault detection device that enables rapid response in the event of a failure through real-time monitoring, improves maintenance efficiency, increases system stability, and allows for remote management through communication-based status check.

Description

Technology Field

[0001] The present invention relates to a communication-based status check device for a DC ground fault detection device, and more specifically, to a communication-based status check device for a DC ground fault detection device that enables rapid response in the event of a failure through real-time monitoring, improves maintenance efficiency, increases system stability, and allows for remote management through communication-based status check. Background Technology

[0002] Prior art related to the present invention includes control of a DC power supply system, a circuit breaker, a protective relay, and system fault monitoring. Patent Document 1 describes a control and protection circuit for a DC power supply system configured by separating an overcurrent / overvoltage detection unit, a ground fault / leakage current detection unit, and a short circuit detection unit, and by using a DC power supply circuit breaker composed of two power switches and one discharge resistor, it rapidly detects overcurrent / overvoltage, ground fault / leakage current, and short circuit accidents and disconnects the DC power supply system to prevent electric shock accidents to the human body and protect the load side. Furthermore, Patent Document 2 describes a circuit breaker and method for interrupting fault currents, which rapidly interrupt fault currents caused by all accidents occurring in the power system and operates to allow recharging of the circuit breaker regardless of the state of the load side, thereby enabling repeated re-energizing and re-circuiting operations according to the operating duty without additional devices. In addition, the protection relay device and system of Patent Document 3 determines whether a ground fault has occurred in each low-voltage feeder by deriving the phase difference between the zero-sequence voltage and the zero-sequence current, and selectively disconnects the low-voltage feeder determined to have a ground fault, thereby enabling selective disconnection of the low-voltage feeders of the multi-channel. In addition, the power system fault monitoring and analysis device having a multi-processing structure of Patent Document 4 enables efficient monitoring of power system faults and rapid recording of fault situations, and also enables effective response to power system faults through accurate analysis of fault situations. Prior art literature

[0003] Registered Patent Publication No. 10-1302572 Registered Patent Publication No. 10-1636479 Registered Patent Publication No. 10-1939562 Registered Patent Publication No. 10-2002461 The problem to be solved

[0004] The present invention aims to provide a communication-based status checking device for a DC ground fault detection device that monitors the reception status of the device through communication and checks the status in real time. means of solving the problem

[0005] A communication-based status check device for a DC ground fault detection device according to a preferred embodiment of the present invention comprises: a zero-sequence current transformer for detecting a ground fault in an electrical circuit; a DC leakage current detection circuit for detecting a leakage current; an analog detection circuit for detecting an analog; a comparator detection circuit for detecting a comparator; a control unit; a contactless output circuit; a CAN communication circuit; and an RS485 communication circuit.

[0006] In addition, the communication-based status check device is characterized by being connected to a data collection device via CAN communication and RS485 communication.

[0007] In addition, the communication-based status checking device comprises a first image current transformer detection device; a second image current transformer detection device; a CAN communication circuit; an RS485 communication circuit; a control unit; and a contactless output circuit; wherein the CAN communication circuit and the RS485 communication circuit are connected to a data collection device. Effects of the invention

[0008] The present invention enables rapid response to failures through real-time monitoring, improves maintenance efficiency, increases system stability, and allows for remote management through communication-based status verification. Brief explanation of the drawing

[0009] FIG. 1 is a block diagram showing a communication-based status check device of the DC ground fault detection device of the present invention. FIG. 2 is a flowchart showing a communication-based status verification method for a DC ground fault detection device of the present invention. FIG. 3 is a block diagram showing the communication circuit of the communication-based status check device in the DC ground fault detection device of the present invention. FIG. 4 is a hierarchical diagram showing the communication-based status check device of the DC ground fault detection device of the present invention. FIG. 5 is a block diagram showing the redundancy configuration of the image current transformer detection device of the present invention. Specific details for implementing the invention

[0010] Hereinafter, a communication-based status verification device for a DC ground fault detection device according to an embodiment of the present invention will be described in detail with reference to the drawings. Descriptions of conventionally known matters below are omitted or simplified to clarify the gist of the present invention. The components included in the description of the present invention operate individually or in a composite combination.

[0011] FIG. 1 is a block diagram showing a communication-based status check device of the DC ground fault detection device of the present invention.

[0012] Referring to FIG. 1, the communication-based status check device of the DC ground fault detection device includes a current transformer (1) that detects a ground fault in an electrical circuit, a DC leakage current detection circuit (2) that detects leakage current, an analog detection circuit (3) that detects analog, a comparator detection circuit (4) that detects comparator, a control unit (5), a contactless output circuit (6), a CAN communication circuit (7), and an RS485 communication circuit (8).

[0013] The communication-based status check device of a DC ground fault detection device precisely detects ground faults occurring in a DC system and transmits the status externally via communication protocols CAN and RS485, enabling remote monitoring and control.

[0014] The zero-sequence current transformer (1) detects current imbalance within the ground fault detection circuit of the electrical circuit and generates a signal by measuring the change in residual current caused by the ground fault in the DC system. The DC leakage current detection circuit (2) converts and processes the leakage current, amplifies and filters the minute current signal received from the zero-sequence current transformer (1), and converts it into a voltage signal that can be processed by the control circuit. The analog detection circuit (3) performs real-time analog monitoring and processes the output signal of the DC leakage current detection circuit (2) into a real-time analog value to measure the magnitude and trend of change of the ground fault. The comparator detection circuit (4) determines the fault threshold and immediately determines whether the real-time value of the analog detection circuit (3) exceeds a preset ground fault threshold using a digital signal (fault / normal).

[0015] The control unit (5) performs central control and logic execution, processes analog / comparator signals using a CPU or microcontroller (MCU), controls the contactless output circuit (6) in the event of a fault, and manages communication protocols. The contactless output circuit (6) commands the operation of an external circuit breaker and, upon detection of a ground fault, outputs an isolated digital signal without physical contact (contactless), such as a relay, to immediately operate the external circuit breaker or alarm device.

[0016] The CAN communication circuit (7) performs high-speed, real-time data communication and is mainly responsible for high-speed, high-reliability communication with the main control device, and transmits real-time ground fault occurrence status and detection values, etc. The RS485 communication circuit (8) performs long-distance, multi-device monitoring and is mainly responsible for long-distance data transmission with a remote monitoring system or multiple devices, and is used for periodic status reporting and setting changes.

[0017] When a ground fault occurs due to insulation failure in the DC wiring, residual current is generated in the zero-sequence current transformer (1), and the leakage current detection circuit (2) amplifies this and converts it into a voltage signal. The analog detection circuit (3) monitors this signal in real time, and the comparator detection circuit (4) determines that this value has exceeded a set threshold of 200mA and transmits a 'fault occurrence' digital signal to the control unit (5). As soon as the control unit (5) receives the fault signal, it drives the contactless output circuit (6) to command the main circuit breaker (external) to trip within 10ms. The control unit (5) notifies the upper control system (e.g., battery management system) in real time via a high-speed CAN bus of the ground fault occurrence and circuit breaker trip command information to induce an immediate response. In addition, a log stating "220mA ground fault occurred and tripped at post point [A]" is transmitted to a remote monitoring server via an RS485 network so that it can be recorded and managed.

[0018] The AI-based Predictive GF Analysis Unit integrates a neural network model within the control unit (5) and learns the minute leakage current change trend data coming from the analog detection circuit (3) over the long term. If the leakage current value has not yet exceeded the threshold value of 200mA but a trend of increasing slightly from 50mA to 80mA to 110mA over the past 48 hours is detected, the AI ​​unit predicts that there is an 80% or greater risk of reaching the threshold value within 24 hours, and the control unit (5) sends a "preventive maintenance warning" message to a remote server via the RS485 communication circuit (8) before the accident occurs to induce preemptive measures.

[0019] The wireless communication module and cloud linkage (Wireless & Cloud Module) adds a wireless communication module (Wi-Fi or LoRa) in addition to CAN and RS485, and the control unit (5) transmits ground fault data directly to a cloud-based central database through this module, and when a ground fault occurs in a place with weak wired communication infrastructure, such as a solar power plant in a remote area, the wireless communication module immediately transmits data to the cloud, enabling real-time monitoring and diagnosis without visiting the site.

[0020] Communication-based remote threshold setting and readjustment integrates a function that allows remote access to the internal threshold setting register of the control unit (5) via the CAN communication circuit (7) and the RS485 communication circuit (8) to change the threshold of the comparator detection circuit (4) in real time, and if the system operator expects the risk of ground fault occurrence to increase according to a specific season or environment (e.g., increased humidity during the rainy season), the ground fault threshold of all detection devices is collectively lowered from 200mA to 150mA via RS485 communication from the office to strengthen safety standards.

[0021] The redundant communication path and automatic recovery (Redundant Communication Path) designates the CAN communication circuit (7) and the RS485 communication circuit (8) as the main / sub-communication paths, and the control unit (5) periodically checks the status of each communication path and has a logic built in to automatically switch to the sub-path if a problem occurs in the main path. In order to report a ground fault, if a problem occurs in the CAN communication circuit (7), which is the main communication path, and there is no response for more than 100ms, the control unit (5) immediately transmits the fault information through the RS485 communication circuit (8) to prevent the omission of the fault report due to the communication failure.

[0022] FIG. 2 is a flowchart showing a communication-based status verification method for a DC ground fault detection device of the present invention.

[0023] Referring to FIG. 2, the communication-based status check device of the DC ground fault detection device performs the following steps: determining whether the detection value of the image current transformer comparator exceeds the fault reference value (S101); if it exceeds the limit, operating the contactless output circuit and communicating the fault signal (S102); detecting the analog value (S103); determining whether the analog detection value exceeds the fault reference value (S104); if it exceeds the limit, operating the contactless output circuit and operating the communication signal (S105); and updating the analog detection value in the communication register (S106).

[0024] The video current transformer (1) and leakage current detection circuit (2) convert the leakage current into a voltage signal and input it when a ground fault occurs, the comparator detection circuit (4) immediately determines whether the input signal exceeds a threshold value in steps S101 and S102, the analog detection circuit (3) converts the input signal into a precise analog value in steps S103 and S104, the control unit (5) executes the logic and judgment of all steps and manages communication, the contactless output circuit (6) outputs a signal for the operation of an external circuit breaker in case of a fault in steps S102 and S105, and the CAN communication circuit (7) / RS485 communication circuit (8) transmits a fault signal and an analog value in steps S102, S105, and S106.

[0025] In the S101 (comparator judgment) step, a leakage current signal is input to the comparator detection circuit (4), and it is determined at high speed whether it exceeds the set fault threshold value V_fault. When the leakage current signal voltage exceeds 3.3V (threshold value) and reaches 4.0V, the comparator immediately sends a 'True' (exceeding) signal to the control unit (5). In the S102 (comparator-based immediate response) step, when it exceeds, the contactless output circuit (6) is operated to trip the external circuit breaker, and an 'immediate fault signal' is transmitted through the CAN / RS485 communication circuit. The control unit (5) sends a trip signal to the circuit breaker through the contactless output (6) and transmits an 'E-STOP: Fault Level 1' message via CAN communication (7). In step S103 (analog detection), the leakage current signal is converted via an ADC through an analog detection circuit (3) to obtain an actual leakage current value (e.g., 225mA) with precision. After the comparator (4) indicates an excess, the control unit (5) uses an ADC to convert the 4.0V signal into an actual physical quantity of 225mA. In step S104 (analog judgment), it is determined once again with precision whether the precisely converted analog detection value exceeds the fault reference value. Since the ADC conversion result of 225mA exceeds the set 200mA reference value, the control unit (5) determines that a 'precision fault has been confirmed'. In step S105 (analog-based communication operation), the contactless output circuit (6) is operated (likely already operated in S102), and a 'precision fault signal' is transmitted via a CAN / RS485 communication circuit. When a 225mA ground fault is detected, a message 'Ground fault: 225mA measured, disconnection complete' is transmitted via RS485 communication (8). In step S106 (communication register update), the precise analog detection value of 225mA is written to the communication register and updated so that an external system can read this value. The value 225 is written to a specific address of the communication register (e.g., 0x1000) so that an external monitoring system can determine the exact magnitude of the current ground fault current.

[0026] Preventing false alarms through dynamic delay time control (Dynamic Delay Control) is achieved by configuring a delay time control unit within the control unit (5), and even if the comparator signal exceeds a threshold value in step S101, the duration and rise rate of the leakage current are analyzed to dynamically determine the delay time T_delay before the operation S102. For temporary noise (less than 10ms): S101 is exceeded, but the control unit (5) sets T_delay to 20ms instead of 0ms to prevent false alarms, and for continuous accident (100ms or more): the control unit (5) sets T_delay to 0ms to immediately execute S102. This logic ensures stability while utilizing the fast speed of S101.

[0027] The S103-based preemptive warning trigger sets a 'preemptive warning threshold value (V_warn)' that is much lower than the fault threshold value (accident) based on the detection value of the analog detection circuit (3), and monitors it constantly in the control unit (5) separately from the judgment logic of S104. If the leakage current measured by S103 exceeds 100mA but is less than 200mA, the control unit (5) does not operate the contactless output circuit (6) and transmits a 'Warning: Leakage current 120mA detected, insulation degradation suspected' message only through the RS485 communication circuit (8).

[0028] The redundancy and time stamp functions of the communication register go beyond simply updating the analog detection value in step S106 to record the final normal value immediately before the fault and the peak value at the time of the fault in separate registers, respectively, and assign a time stamp of 1ms to each data, such as Register 1 (Fault Peak): 225mA @ 15:30:10.550, Register 2 (Immediate Normal): 50mA @ 15:30:10.540. These detailed records are transmitted to an external system when the communication register is updated and are used to precisely analyze the trend of ground fault current change before and after the fault.

[0029] Remote Loopback Diagnostics based on CAN and RS485 communication is performed by the control unit (5) periodically sending self-diagnostic commands to the CAN communication circuit (7) and the RS485 communication circuit (8), and causing the communication circuit to return these commands back to the control unit (5) to check the health of the communication circuit itself in real time, and the control unit (5) sends a diagnostic packet to the CAN communication circuit (7) every 1 second, and if the CAN circuit fails to return it within 5ms, the control unit (5) determines that there is a CAN communication failure and automatically switches to RS485 communication to secure an accident reporting channel.

[0030] FIG. 3 is a block diagram showing the communication circuit of the communication-based status check device in the DC ground fault detection device of the present invention.

[0031] Referring to FIG. 3, the image current transformer detection device (10) is connected to the data collection device (20) via CAN communication (7) and RS485 communication (8).

[0032] The video current transformer detection device (10) acts as a field sensor node that detects DC ground faults, and the data collection device (20) acts as a central gateway that integrates, analyzes, and logs data collected from multiple field nodes. The two devices are connected via redundant communication channels, namely CAN communication (7) and RS485 communication (8), to ensure data reliability.

[0033] The image current transformer detection device (10) independently detects a ground fault, outputs a cutoff signal, and transmits the status via communication. The image current transformer (1) physically detects the actual leakage current, converts it into an electrical signal, and generates a basic signal to send the measurement data to the data collection device (20). The leakage current detection circuit (2) / analog detection circuit (3) converts and corrects the detected signal into a precise analog measurement value and serves as a precise measurement value data source requested by the data collection device (20). The comparator detection circuit (4) / contactless output circuit (6) determines at ultra-high speed when a threshold is exceeded, immediately outputs an external cutoff command, and transmits an emergency fault signal to the data collection device (20) in the event of an accident. The control unit (5) controls all circuits, manages communication protocols to update data in the communication register, responds to requests from the data collection device (20), and formats and transmits the collected data. The CAN communication circuit (7) is responsible for transmitting and receiving high-speed real-time data (Heartbeat, emergency alarm), is used as the main communication channel, and is responsible for real-time interlocking with the data collection device (20). The RS485 communication circuit (8) is responsible for transmitting and receiving detailed logs and setting values ​​for long-distance and multi-device monitoring, and is used as a secondary communication channel or a channel for remote setting.

[0034] The data collection device (20) periodically requests the 'current leakage current value' and 'device status' from the control unit (5) of the image current transformer detection device (10) via stable RS485 communication (8), and the control unit (5) updates the analog detection value in the communication register and responds to the data collection device (20) with the current leakage current value of 50mA and the device ID via RS485 communication (8). The data collection device (20) records these values ​​in the central log. An operator issues a command to change the ground fault threshold from 200mA to 150mA via the data collection device (20), and the data collection device (20) transmits the 'threshold value 150mA setting' command to the control unit (5) via high-speed CAN communication (7). The control unit (5) receives this command and immediately updates the threshold values ​​of the comparator detection circuit (4) and its own logic.

[0035] Communication-based remote sensor diagnostics and calibration is performed by configuring a sensor health diagnostic module inside the control unit (5) of the image current transformer detection device (10) to periodically measure the 'zero point offset' value when the leakage current is 0, and the data collection device (20) remotely checks this offset value and, if necessary, transmits a 'zero point correction' command to the control unit (5) via CAN communication (7) to restore the measurement precision of the sensor. When the data collection device (20) receives a report from the image current transformer detection device (10) stating that 'an offset value of 10mA is measured in a state of 0mA leakage current,' the data collection device (20) issues a command to the control unit (5) of the image current transformer detection device (10) to 'always correct -10mA from the measured value' to automatically correct the error caused by the aging of the sensor in software.

[0036] Intelligent dual communication status detection and priority control is configured with a communication health monitoring unit in the control unit (5) to monitor the packet reception success rate and latency of the CAN communication circuit (7) and the RS485 communication circuit (8) in real time. Normally, RS485 is used, and the control unit (5) performs logic to automatically switch to CAN communication when it is determined that the CAN communication status is more stable or when an emergency situation occurs. Normally, the slow but stable RS485 is used, but when a 150mA warning (V_warn) is detected, the control unit (5) switches to CAN communication (7) within 30ms to increase the warning and real-time data transmission speed.

[0037] A communication-based firmware remote update function (FOTA: Firmware Over The Air / Bus) includes a remote firmware update module in the control unit (5), and the data collection device (20) transmits the firmware file of the detection device (10) by utilizing the long-distance data transmission capability of RS485 communication (8). The control unit (5) receives this file, updates the firmware itself, and reboots. When a new ground fault detection algorithm is developed, the operator transmits the firmware file via RS485 communication to dozens of video current transformer detection devices (10) through the central server (20), and the video current transformer detection devices (10) start operating with the new algorithm using this file.

[0038] Distributed Fault Judgment integrates logic that determines whether a distributed ground fault has occurred across the entire communication network by combining ground fault analog values ​​received from multiple detection devices (10) by a data collection device (20), and the data collection device (20) feeds back the distributed judgment result to each image current transformer detection device (10). When detection devices A, B, and C each detect 80mA, 70mA, and 50mA, respectively, each image current transformer detection device (10) does not trip because it does not exceed a reference value of 200mA. However, the data collection device (20) detects that the sum of these three values ​​exceeds 200mA and transmits a 'distributed ground fault warning' to all devices to increase the protection level of the entire system.

[0039] FIG. 4 is a hierarchical diagram showing the communication-based status check device of the DC ground fault detection device of the present invention.

[0040] Referring to FIG. 4, the image current transformer detection device (10) includes a first layer image current transformer (1), a second layer DC leakage current detection circuit (2), a third layer analog detection circuit (3), a comparator detection circuit (4), a communication unit CAN communication circuit (7), an RS485 communication circuit (8), a control unit (5), and a contactless output circuit (6).

[0041] The image current transformer detection device (10) operates in a five-stage hierarchical structure from physical sensing (first layer) to digital control and external communication (communication unit).

[0042] The first layer video current transformer (1) sensing layer physically detects the residual current (leakage current) of the circuit and converts it into a proportional weak current or voltage signal, the second layer DC leakage current detection circuit (2) signal conversion layer amplifies and filters the weak signal of the first layer so that the control unit (5) can process it, and creates a voltage signal with noise removed, the third layer analog detection circuit (3) precision measurement layer converts the signal of the second layer into a precise digital value through a high-resolution ADC (Analog-to-Digital Converter) to measure the actual magnitude of the leakage current, and the third layer comparator detection circuit (4) high-speed judgment layer directly receives the signal of the second layer, compares it with a preset threshold value, and rapidly outputs a digital signal in milliseconds to determine whether a ground fault has occurred. The central control layer of the control unit (5) processes data from all layers and controls the contactless output circuit (6) and communication (7, 8) based on the high-speed judgment of the comparator detection circuit (4) and the precise measurement results of the analog detection circuit (3). The contactless output circuit (6) fault response layer outputs an isolated driving signal without physical contact to trip an external circuit breaker according to the command of the control unit (5). The communication unit CAN communication circuit (7) and RS485 communication circuit (8) external interlock layer transmits the device status, measurement values, and fault logs processed by the control unit (5) to an external data collection device or a higher-level system.

[0043] Parallel processing when a ground fault occurs: ground fault occurs during the operation of the first and second layers -> the image current transformer (1) detects leakage current -> the leakage current detection circuit (2) amplifies the signal to generate a 4.0V voltage signal, and in the parallel judgment of the third layer, the 4.0V signal is input to the comparator detection circuit (4) for high-speed judgment (4), immediately determining that it exceeds the threshold value of 3.3V, and transmitting the 'ultra-high-speed fault signal' to the control unit (5). At the same time, in the precision measurement (3), the 4.0V signal is input to the analog detection circuit (3) and converted into a precision measurement value of 225mA via the ADC. In the immediate response of the control unit (5), as soon as the control unit (5) receives the high-speed fault signal from the comparator (4), it immediately operates the contactless output circuit (6) to trip the circuit breaker. In the communication report, the control unit (5) records the precision measurement value (225mA) and the time of the accident in the communication register, and reports the 'emergency trip and measurement value' to the upper system through the CAN communication circuit (7).

[0044] The second layer-based active noise removal and filter layer adds a signal processing DSP (Digital Signal Processor) or an adaptive filter to the DC leakage current detection circuit (2) to detect the surrounding environment or switching noise frequency band in real time and implement an active noise removal function that selectively attenuates only the corresponding noise. When noise of a specific frequency (F_noise) is introduced into the leakage current signal by inverter switching in the photovoltaic power generation system, the DSP learns F_noise to remove only the noise component and transmits only the pure leakage current component to the third layer (3, 4), thereby drastically reducing detection errors and false alarm rates.

[0045] The third layer-based multiple threshold and risk level determination is based on the precision value measured by the analog detection circuit (3), and the control unit (5) defines three or more risk levels (warning, caution, fault), and sets the operation method of the contactless output (6) and the priority of the communication message differently according to each level. Warning level (exceeding mA): The contactless output (6) does not operate, but a message of 'low priority maintenance needed' is transmitted via RS485 communication (8). Caution level (exceeding 150mA): The contactless output (6) does not operate, but a message of 'medium priority monitoring reinforcement' is transmitted via CAN communication (7). Fault level (exceeding 200mA): According to S102, the contactless output (6) operates immediately and a message of 'highest priority trip report' is transmitted via CAN communication (7).

[0046] The communication-based status feedback of the non-contact output circuit (6) is performed by adding a self-output monitoring sensor inside the non-contact output circuit (6) to check whether an external circuit breaker trip signal is applied normally, and feeding this result back to the control unit (5). Even though the control unit (5) has issued a trip command to the non-contact output circuit (6), if the feedback sensor detects a 'trip signal output failure,' the control unit (5) immediately reports a 'trip attempt failure' via CAN communication (7) and executes a secondary response logic such as attempting a backup circuit breaker trip.

[0047] Multi-Layer Synchronization based on CAN communication is achieved by the control unit (5) performing precise time synchronization with an external system using CAN communication (7), reflecting this synchronized time at the time of updating the threshold of the third layer ADC sampling and comparator (4), and when a command to change the trip threshold to 150mA at 10:00:00.000 is received via CAN communication from the external system, the control unit (5) controls the application of this command to the third layer circuit at the time exactly synchronized at 10:00:00.000, thereby securing simultaneity between multiple detection devices and communication-based precise control capabilities.

[0048] FIG. 5 is a block diagram showing the redundancy configuration of the image current transformer detection device of the present invention.

[0049] Referring to FIG. 5, the image current transformer detection device includes a first image current transformer detection device (11), a second image current transformer detection device (12), a CAN communication circuit (7), an RS485 communication circuit (8), a control unit (5), and a contactless output circuit (6), and the CAN communication circuit (7) and the RS485 communication circuit (8) are connected to a data collection device (20).

[0050] The first image current transformer detection device (11) is a complete ground fault detection circuit including an independent image current transformer for Channel 1 (main detection), a leakage current detection circuit, and an analog / comparator detection circuit. It is responsible for ground faults in a specific circuit (Line A). The second image current transformer detection device (12) is equipped with an independent ground fault detection circuit, identical to Channel 2 (auxiliary / redundant detection) (11). It is responsible for ground faults in another circuit (Line B) or performs the role of detection redundancy for the first image current transformer detection device (11). The control unit (5) performs integrated central control, integrates and analyzes all data coming from the first image current transformer detection device (11) and the second image current transformer detection device (12), and controls the contactless output (6) and communication unit (7, 8) when a ground fault occurs. The contactless output circuit (6) generates an output signal that trips an external circuit breaker according to the command of the integrated trip command control unit (5). It can operate if a ground fault is detected at either the first image current transformer detection device (11) or the second image current transformer detection device (12). The CAN communication circuit (7) is responsible for transmitting real-time emergency alarms and control commands to the high-speed communication data collection device (20). The RS485 communication circuit (8) is responsible for detailed logs, periodic status reports, and remote setting changes to the long-distance / multi-communication data collection device (20).

[0051] The first image current transformer detection device (11) detects a leakage current of 50mA in the Line A circuit and transmits this analog measurement value to the control unit (5). The second image current transformer detection device (12) detects a leakage current of 0mA in the Line B circuit and transmits this value to the control unit (5). The leakage current in Line A suddenly rises to 250mA, and the comparator of the first image current transformer detection device (11) detects that it has exceeded the threshold value. The control unit (5) immediately receives a fault signal from the first image current transformer detection device (11) and operates the contactless output circuit (6) to trip the circuit breaker connected to Line A. The control unit (5) transmits a message in real time to the data collection device (20) via high-speed CAN communication, stating 'Emergency fault, Channel 1, 250mA measured'. RS485 communication (8) then transmits a detailed log including the ‘Line A trip log’ and the current status of Line B (0mA normal) to (20) via RS485 communication.

[0052] False alarm filtering through mutual channel comparison is performed by adding a mutual comparison logic inside the control unit (5) to compare the measurement values ​​of the first image current transformer detection device (11) and the second image current transformer detection device (12) in real time, and if a deviation outside the allowable range occurs between the two channels, it is determined that there is an abnormality in the sensor or the circuit itself and the operation of the contactless output (6) is temporarily delayed. In the case where the first image current transformer detection device (11) and the second image current transformer detection device (12) detect a ground fault of the same circuit in a duplicate manner, if the first image current transformer detection device (11) detects 250mA but the second image current transformer detection device (12) detects only 5mA, the control unit (5) determines that the sensor of the first image current transformer detection device (11) is malfunctioning, delays the trip, and then transmits a 'sensor error warning' to the data collection device (20) via RS485.

[0053] The dual-channel based composite ground fault judgment criteria implements a composite judgment logic in which the control unit (5) determines a fault even if it does not exceed a single criterion by summing the measured values ​​of two detection devices (11, 12) (Additive Fault) or calculating the ratio (Differential Fault). Additive Fault: When the first image current transformer detection device (11) detects 120mA and the second image current transformer detection device (12) detects 130mA (each is less than the trip threshold of 200mA), the control unit (5) determines that the sum of the two values ​​(250mA) exceeds the composite threshold (220mA) and operates the contactless output (6) to trip the circuit breaker. This is useful when multiple micro ground faults occur simultaneously and the sum of the leakage current reaches a dangerous level.

[0054] CAN communication-based emergency tripping priority assignment is achieved by the control unit (5) utilizing the CAN communication (7) protocol to set the ID (Priority) of the communication message differently depending on which of the two channels (11, 12) a ground fault occurred, thereby allowing the data collection device (20) and the upper system to immediately identify the priority of the emergency trip, such as: first image current transformer detection device (11) fault: CAN message ID = 0x100 (highest priority), second image current transformer detection device (12) fault: CAN message ID = 0x101 (second priority). Through this, the data collection device (20) can command the main circuit breaker to operate within 1ms upon receiving the 0x100 message, and command the circuit breaker to operate after a 5ms delay upon receiving the 0x101 message, thereby enabling flexible response according to the importance of the system.

[0055] The separation of remote settings per channel based on RS485 divides the memory map of the control unit (5) so that the data collection device (20) can remotely set the threshold value, delay time, etc. of the first channel (11) and the second channel (12) completely independently via RS485 communication (8), and the operator can set the trip threshold value of the first video current transformer detector (11) to 200mA and the trip threshold value of the second video current transformer detector (12) to 150mA differently via RS485. This is useful when the two channels are responsible for circuits with different levels of importance or environments (e.g., outdoor wiring with high humidity, indoor wiring with low humidity).

[0056] The AI-based leakage current change prediction unit integrates a time-series analysis AI model, such as an RNN (Recurrent Neural Network), into the control unit (5) to learn and predict the minute non-linear leakage current rise pattern of the analog detection circuit (3). When the leakage current is still below the threshold (200mA) but the AI ​​predicts that there is a '90% or higher probability of reaching the ground fault threshold within 3 hours,' it transmits an 'emergency warning of preventive maintenance required' via CAN communication (7) without operating the contactless output (6).

[0057] In communication-based dynamic trip delay control, when a data collection device (20) transmits information on the field wiring environment (length, humidity, etc.) to a control unit (5) via RS485 communication (8), the control unit (5) calculates and applies the delay time (T delay) in real time before contactless output (S102) after comparator detection (S101) based on this information, and in a dry environment (T delay = 5ms), when humidity increases during rain (information received via RS485), the control unit (5) determines that there is a low possibility that the ground fault signal will be mistaken for noise, and responds quickly by shortening T_delay to 0ms.

[0058] Automatic adjustment of emergency cutoff priority based on communication protocol is performed by the control unit (5) dynamically changing the priority of the CAN communication (7) message ID according to the CAN standard based on the magnitude or risk level of the ground fault current and transmitting it, and setting the CAN message ID to 0x0A (highest emergency) when a ground fault with a leakage current of 200mA occurs so that it reaches the collection device (20) before other CAN devices, and setting the ID to 0x1A (general warning) when a 50mA warning occurs.

[0059] The second layer-based active noise blocking filter adds a circuit such as a PLL (Phase-Locked Loop) to the DC leakage current detection circuit (2) to track and cancel periodic noise of a specific frequency introduced from the outside, thereby increasing the purity of the signal transmitted to the third layer (3, 4), and when noise of a specific switching frequency of the solar inverter is introduced, the DC leakage current detection circuit (2) detects this frequency and generates an inverse phase signal to remove the noise in real time, thereby accurately extracting only the ground fault signal.

[0060] The trip signal integrity feedback of the contactless output circuit is provided by adding an output voltage / current detection sensor to the output terminal of the contactless output circuit (6), and integrating logic in which the control unit (5) checks the feedback signal within 5ms after the trip signal is output, and when the control unit (5) issues a trip command to (6) but the feedback sensor reports 'output voltage abnormality', the control unit (5) immediately sends a 'trip failure and device abnormality' message via RS485 communication (8) and attempts to trip the backup circuit breaker.

[0061] Communication-based dual channel cross-validation integrates logic in which the control unit (5) compares the analog detection values ​​(S106) of the first image current transformer detector (11) and the second image current transformer detector (12), and generates a 'sensor mismatch warning' if the deviation rate of the leakage current measurement values ​​between the two channels exceeds 15%, and when the first image current transformer detector (11) measures 100mA and the second image current transformer detector (12) measures 50mA (50% deviation), the control unit (5) transmits a 'channel imbalance warning' via RS485 communication (8) instead of tripping to indicate the need for sensor calibration.

[0062] The S106-based leakage current log circulation buffer and remote search allocate a circulation FIFO buffer (10 minutes) to the control unit (5) to store an analog detection value (S106) with a time stamp of 1ms, and provide a function for the data collection device (20) to remotely request and search for logs of a specific time period via RS485 communication (8), and when the data collection device (20) requests 'leakage current data from 30 seconds before the accident occurred to 5 seconds after the accident occurred', the control unit (5) extracts the corresponding data from the buffer and transmits it, thereby providing precise data necessary for accident cause analysis.

[0063] The CAN communication-based multi-device time synchronization master / slave function performs precise time synchronization within 1ms with an external RTC (Real-Time Clock) module or data collection device (20) through a CAN communication circuit (7), uses this time for the operation of a contactless output (6) and the time stamp of a communication message (S102, S105), and a number of detection devices (10) are simultaneously synchronized via CAN communication so that accident logs generated by multiple devices are recorded in a central system at an accurate time of occurrence within a 1ms error range.

[0064] Communication-based remote firmware update and integrity verification integrates Firmware Over The Air (FOTA) logic that separates the firmware area of ​​the control unit (5) into a bootloader area and an application area, and performs a Cyclic Redundancy Check (CRC) integrity verification on a new firmware file received via RS485 communication (8), and when the data collection device (20) transmits the new firmware via RS485, the control unit (5) checks the CRC value of the firmware to determine whether the data is corrupted during transmission, and only proceeds with the update if there is no corruption to prevent device malfunction.

[0065] Automatic correction of the permanent residual current offset based on S104 is performed by the control unit (5) software-wise correcting the value when the precision measurement value (S103) of the analog detection circuit (3) is confirmed to be in a 'normal' state (S104) for a long period (e.g., 24 hours), defining the measured minute residual current value (e.g., 2mA) as the 'zero point offset' and automatically subtracting it from all subsequent measurements. When 3mA is measured even in a normal state due to sensor aging, this value is set as the offset, and the value corrected to 47mA is updated in the communication register (S106) when 50mA is measured, thereby maintaining the measurement precision for a long period.

[0066] RS485-based multi-device grouping and batch control implements a communication protocol in which a data collection device (20) groups multiple detection devices (10) into a logical group (e.g., Zone A, Zone B) via RS485 communication (8) and can simultaneously change the settings of the entire group with a single command (e.g., 'change the entire threshold of Zone A to 180mA'), and when the data collection device (20) transmits the command 'set the threshold of Group A to 180mA' via RS485, 10 detection devices (10) belonging to Group A change their settings simultaneously within 100ms.

[0067] The priority and automatic switching logic of the redundant communication channels is integrated such that the control unit (5) designates the CAN communication (7) as the main communication (Master) and the RS485 communication (8) as the auxiliary communication (Backup), and automatically switches all data transmission to RS485 within 50ms in the event of a CAN communication failure through periodic CAN communication heartbeat checks, and if a heartbeat is not received for 100ms due to damage to the CAN communication cable, the control unit (5) switches the communication channel to RS485 and reports a message to the data collection device (20) via RS485 stating 'CAN communication channel failure, backup mode in progress'.

[0068] The present invention is not limited to the specific preferred embodiments described above, and any person skilled in the art to which the invention pertains can make various modifications without departing from the essence of the invention as claimed in the claims, and such modifications will be within the scope of the claims. Explanation of the symbols

[0069] 1: Video current transformer 2: DC leakage current detection device 3: Analog detection circuit 4: Comparator detection circuit 5: Control unit 6: Contactless output circuit 7: CAN communication circuit 8: RS485 communication circuit 10: Video current transformer detection device 11: First video current transformer detection device 12: Second video current transformer detection device 20: Data collection device

Claims

Claim 1 A communication-based status checking device comprising: a zero-sequence current transformer for detecting a ground fault in an electrical circuit; a DC leakage current detection circuit for detecting leakage current; an analog detection circuit for detecting analog; a comparator detection circuit for detecting comparators; a control unit; a contactless output circuit; a CAN communication circuit; and an RS485 communication circuit; wherein the communication-based status checking device comprises: a first zero-sequence current transformer detection device; a second zero-sequence current transformer detection device; a CAN communication circuit; an RS485 communication circuit; and a control unit; and a contactless output circuit; comprising, wherein the CAN communication circuit and the RS485 communication circuit are connected to a data acquisition device, and the control unit integrates a neural network model internally, learns minute leakage current change trend data coming from an analog detection circuit, and if a trend of rising from 50mA -> 80mA -> 110mA over the past 48 hours is detected even though the leakage current value has not exceeded a threshold of 200mA, predicts that 'there is an 80% or higher risk of reaching the threshold within 24 hours' and induces preemptive measures by transmitting a 'preventive maintenance warning' message to a remote server via the RS485 communication circuit before an accident occurs; a wireless communication module and cloud interoperability that adds a wireless communication module in addition to CAN and RS485, transmits ground fault data to a cloud-based central database through this module, and when a ground fault occurs, the wireless communication module transmits data to the cloud to enable monitoring and diagnosis; and the CAN communication circuit and the RS485 communication circuit Communication-based remote threshold setting and readjustment integrating a function to change the threshold of a comparator detection circuit by remotely accessing an internal threshold setting register;A sensor health diagnosis module is configured within the control unit of the zero-sequence current transformer detection device to periodically measure the 'zero point offset' value when the leakage current is zero; the data acquisition device remotely verifies this offset value and, if necessary, transmits a 'zero point correction' command to the control unit via CAN communication to restore the sensor's measurement precision; and when the data acquisition device receives a report from the zero-sequence current transformer detection device stating 'an offset value of 10mA is measured in a state of 0mA leakage current,' the data acquisition device issues a command to the control unit of the zero-sequence current transformer detection device to 'constantly correct the measured value by -10mA' to correct errors caused by sensor aging, thereby providing communication-based remote sensor diagnosis and correction; the data acquisition device integrates logic that aggregates ground fault analog values ​​received from multiple detection devices to determine whether a distributed ground fault has occurred across the entire communication network; the data acquisition device feeds back this distributed determination result to each zero-sequence current transformer detection device; and when detection devices A, B, and C detect 80mA, 70mA, and 50mA, respectively, each The image current transformer detection device does not trip as it does not exceed a reference value of 200mA, and the data acquisition device detects that the sum of these three values ​​exceeds 200mA, and transmits a 'distributed ground fault warning' to all devices to increase the protection level of the entire system, thereby sharing distributed fault judgment information;A communication-based status check device for a DC ground fault detection device, characterized by performing false alarm filtering through mutual channel comparison, wherein a mutual comparison logic is added within the control unit to compare the measured values ​​of the first image current transformer detection device and the second image current transformer detection device, and if a deviation outside the allowable range occurs between the two channels, it is determined to be an abnormality of the sensor or the circuit itself and the operation of the contactless output is delayed, and in the case where the first image current transformer detection device and the second image current transformer detection device detect a ground fault of the same circuit in a redundant manner, if the first image current transformer detection device detects 250mA but the second image current transformer detection device detects only 5mA, it is determined to be a sensor malfunction of the first image current transformer detection device, the trip is delayed, and then a 'sensor error warning' is transmitted to the data acquisition device via RS485. Claim 2 delete Claim 3 delete

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