Power line loss abnormity monitoring system and monitoring method

Abstract

The invention relates to the technical field of power transformation protection replacement, in particular to a power line loss abnormity monitoring system and monitoring method. The host and the extension sets are provided with communication modules, and the communication modules provide wireless communication links and pulse signals. A power supply circuit, a current acquisition circuit, a leakage current acquisition circuit, a voltage acquisition circuit, a phase sequence measurement circuit, an MCU core control circuit and a 4G communication circuit are integrated in the host and the extension set. Time service and communication are combined into one, an independent high-precision GPS module is omitted, reference pulses are distributed through 4G after Beidou signals are acquired at the outdoor host, and sub-millisecond synchronization can be achieved without receiving satellite signals by the indoor extensions. The phase sequence judgment precision is high, A, B and C three-phase and single-phase user attribution phases can be reliably distinguished, the extension set can be put into use only by clamping a clamp meter, wiring is not needed, relaying is not needed, and an original metering seal does not need to be damaged.

Description

Technical Field

[0001] This invention relates to the field of line loss monitoring technology, and in particular to a power line loss anomaly monitoring system and monitoring method. Background Technology

[0002] With the deepening of the "full coverage and full data collection" construction of low-voltage distribution areas, abnormal line loss has become a key target for power supply companies' refined management. Currently, the commonly used line loss anomaly monitoring technologies in the industry mainly include the following: traditional manual on-site verification combined with handheld phase sequence meters and clamp meters, which is inefficient, time-consuming, and cannot achieve real-time monitoring; split-type line loss monitoring devices with short-range wireless communication, although enabling data interaction between the main unit and the sub-unit, are limited by communication distance, complex electromagnetic environment on site, and building obstruction, resulting in high packet loss rate and poor network reliability.

[0003] While power line carrier communication solutions eliminate the need for additional wiring, the low-voltage power grid itself suffers from significant noise, attenuation, and impedance variations, necessitating the installation of multiple relays and complicating on-site installation and commissioning. A few devices employing high-precision GPS / BeiDou timing for phase sequence identification can solve the phase sequence problem, but they typically rely solely on the BeiDou module for timing, while data transmission still depends on other communication methods. This results in a complex system structure, high cost, and high power consumption. Furthermore, the BeiDou module is prone to loss of lock-on when the signal is weak indoors or in basements.

[0004] Therefore, a power line loss anomaly monitoring system and monitoring method is needed that can realize dual functions of communication and time synchronization, significantly simplify the system structure, completely eliminate the limitations of distance and environment on communication, combine local zero-crossing detection circuits of each node to realize high-precision phase sequence synchronization determination between the host and the sub-units, centrally collect the master meter data of the host and collect the branch data of the sub-units, and perform in-phase summary calculation after combining the accurate phase sequence to accurately locate the abnormal point of line loss to meet the needs of the current environment. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that the commonly used line loss anomaly monitoring technologies in the industry have many defects and cannot meet the current work requirements for line loss anomaly monitoring and investigation.

[0006] The above-mentioned technical problems are solved by the following technical solution: This invention proposes a power line loss anomaly monitoring system, which includes, Both the main unit and the extension unit are equipped with communication modules, which provide wireless communication links and pulse signals. The main unit and the extension unit are internally equipped with power supply circuit, current acquisition circuit, leakage current acquisition circuit, voltage acquisition circuit, phase sequence measurement circuit, MCU core control circuit and 4G communication circuit. The host collects the current, voltage and leakage current parameters of the main line and uses the communication module to establish data interaction with the extension units; The main unit receives parameters reported by the extension units and performs line loss anomaly analysis and judgment.

[0007] In a preferred embodiment of the power line loss anomaly monitoring system described in this invention: The MCU core control circuit is connected to the output terminals of the current acquisition circuit, leakage current acquisition circuit, and voltage acquisition circuit respectively through digital interfaces; The pulse output terminal of the phase sequence measurement circuit is connected to the MCU core control circuit, and the serial communication interface of the 4G communication circuit is connected to the MCU core control circuit. The MCU core control circuit acquires and digitizes the parameter signals and performs coordinated transmission.

[0008] In a preferred embodiment of the power line loss anomaly monitoring system described in this invention: The current acquisition circuit includes a current transformer unit and an operational amplifier unit; The current transformer unit is connected to the A / D conversion input channel of the MCU core control circuit through the operational amplifier unit, and is used to perform non-contact sampling of the line current.

[0009] In a preferred embodiment of the power line loss anomaly monitoring system described in this invention: The leakage current acquisition circuit includes a leakage current mutual inductance unit and a leakage current operational amplifier unit; The leakage current transformer unit is connected to the leakage current conversion input channel of the MCU core control circuit through an optimized sampling resistor network, so as to realize early warning of leakage faults. The voltage acquisition circuit includes a resistor divider network and an opto-isolated operational amplifier unit; The resistor divider network is connected to the voltage conversion input channel of the MCU core control circuit through the opto-isolated operational amplifier unit, so as to achieve electrical isolation and signal amplification processing of high voltage AC voltage.

[0010] In a preferred embodiment of the power line loss anomaly monitoring system described in this invention: The phase sequence measurement circuit includes a zero-crossing detection sub-circuit composed of an isolated analog voltage comparison unit, which uses optocoupler isolation to achieve full electrical isolation from the 220V AC power supply; The phase sequence measurement circuit is connected to the timer capture pin of the MCU core control circuit through the pulse output interface to generate a precise pulse signal at the zero-crossing point of the AC voltage.

[0011] A monitoring method includes the aforementioned power line loss anomaly monitoring system, and, The reference clock pulse signal provided by the BeiDou time synchronization and communication module is used as the synchronization clock. The host and each sub-unit capture the zero-crossing pulse time interval of their respective phase sequence, and each sub-unit transmits the time interval to the host. The host compares the time intervals of each extension with the time intervals recorded by the host to determine the phase sequence; Based on the phase sequence determination and the collected current, voltage, power, and leakage current data, anomaly analysis and judgment of line loss are performed.

[0012] In a preferred embodiment of the monitoring method described in this invention: Each sub-unit uses the same reference clock pulse signal as the main unit as a synchronization clock. After receiving the rising edge of the reference clock pulse, it starts an internal timer to keep track of the time interval between the rising edges of the zero-crossing pulses of its respective connection phase sequence. The sub-unit records the time intervals through the timer module of the MCU core control circuit, packages the time intervals, and transmits them to the host in real time using the communication module, supporting distributed phase sequence synchronization judgment.

[0013] In a preferred embodiment of the monitoring method described in this invention: The host performs time interval comparison through the corresponding MCU core control circuit, comparing the time interval of the extension unit's transmission with the A, B, and C phase times recorded by the host one by one; Set a preset tolerance range for similarity assessment; If the difference between the extension unit's time interval and the master unit's phase sequence time interval is within the tolerance range, then the extension unit is determined to be in the corresponding phase sequence.

[0014] In a preferred embodiment of the monitoring method described in this invention: The host computer performs line loss anomaly analysis and judgment through the corresponding MCU core control circuit; Based on the determined phase sequence, the power value of each phase sequence is calculated from the collected current and voltage data. The total power is compared with the sum of the power of each branch, and the cumulative difference between the total current and voltage and the current and voltage of each branch is calculated. Set a difference threshold and compare the cumulative difference with the difference threshold; If the difference exceeds the threshold, it is determined to be an abnormal line loss; If the difference threshold is not exceeded, the line loss is considered normal.

[0015] The beneficial effects of this invention are as follows: Timing and communication are integrated into one, eliminating the need for a separate high-precision GPS module and reducing costs by more than 30%. Simultaneously, after the BeiDou signal is acquired at the outdoor host, it is distributed as a reference pulse via 4G, allowing the indoor unit to achieve sub-millisecond synchronization without receiving satellite signals. Phase sequence determination accuracy is high, reliably distinguishing between A, B, and C phases and single-phase user affiliation. The unit only needs to be clamped to a meter for immediate use, requiring no wiring, repeaters, or disruption of existing metering seals. Both the host and unit circuits employ a fully isolated design, ensuring equipment and personnel safety. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0017] Figure 1 A connection architecture diagram of the power line loss anomaly monitoring system of the present invention is shown.

[0018] Figure 2 The schematic diagram of the power supply circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0019] Figure 3 A schematic diagram of the step-down conversion section of the power supply circuit of the present invention is shown.

[0020] Figure 4 The schematic diagram of the current acquisition circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0021] Figure 5 The schematic diagram of the leakage current acquisition circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0022] Figure 6 A schematic diagram of the voltage acquisition circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0023] Figure 7 A schematic diagram of the phase sequence measurement circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0024] Figure 8 The schematic diagram of the MCU core control circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0025] Figure 9 A schematic diagram of the 4G communication circuit in the power line loss anomaly monitoring system of the present invention is shown.

[0026] Figure 10 A flowchart of the monitoring method of the present invention is shown. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0028] The terminology used in this invention refers to those general terms currently widely used in the art in consideration of the functionality of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new techniques. Furthermore, specific terms may be chosen independently, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of the invention.

[0029] Reference Figures 1-6 This embodiment provides a power line loss anomaly monitoring system.

[0030] The entire system includes a host 1 and multiple sub-units 2. Both host 1 and sub-units 2 are equipped with a communication module 3. Specifically, the communication module 3 is a Beidou timing + 4G communication module. The communication module 3 integrates Beidou timing function and 4G wireless communication function to provide wireless communication link and high-precision reference clock pulse signal. It can realize data synchronization transmission and timing reference of each node in the system, and ensure the reliability of data interaction and the accuracy of phase sequence determination in wide-area deployment scenarios.

[0031] The internal structures of the main unit 1 and the sub-unit 2 are similar, both integrating a power supply circuit 4, a current acquisition circuit 5, a leakage current acquisition circuit 6, a voltage acquisition circuit 7, a phase sequence measurement circuit 8, an MCU core control circuit 9, and a 4G communication circuit 10. The power supply circuit 4 provides a stable power supply to the system; the current acquisition circuit 5 samples the line current; the leakage current acquisition circuit 6 detects leakage current; the voltage acquisition circuit 7 measures voltage parameters; the phase sequence measurement circuit 8 generates zero-crossing pulses and combines them with the reference clock pulse signal provided by the communication module 3 to calculate the phase sequence; the MCU core control circuit 9 is the core processor, used to receive and process signals from each acquisition circuit, and to achieve data communication control through the 4G communication circuit 10.

[0032] In the entire workflow, host 1 is configured to collect the current, voltage, and leakage current parameters of the main line. The MCU core control circuit 9 processes these parameters in real time, calculating indicators such as total power and total leakage current. Simultaneously, host 1 uses communication module 3 to establish a wireless data exchange channel with each sub-unit 2, achieving wide-area coverage via the 4G public network without the need for additional repeaters or wiring, ensuring the stability and real-time performance of data transmission. Each sub-unit 2 performs local data collection for its power-consuming branch, sampling branch current, voltage, and leakage current parameters through internal circuitry, calculating local phase sequence information, and then packaging and uploading these parameters to host 1.

[0033] After receiving the parameters reported by the extension unit 2, the host 1 performs line loss anomaly analysis and judgment in the MCU core control circuit 9. The host 1 first integrates the total line parameters and the parameters of each branch, performs in-phase grouping and summarization according to the phase sequence information, calculates the difference between the total power and the sum of the branch power, and if the difference exceeds the preset threshold, it is judged as a line loss anomaly.

[0034] As one embodiment provided, such as Figures 1-9 , Based on Embodiment 1, this embodiment further discloses in detail the connection architecture and functional details of the internal circuit modules of the host 1 and the sub-unit 2, and demonstrates the integration method of the MCU core control circuit 9 with other acquisition circuits, as well as the internal structure and signal processing flow of each acquisition circuit.

[0035] The MCU core control circuit 9 is connected to the output terminals of the current acquisition circuit 5, leakage current acquisition circuit 6, and voltage acquisition circuit 7 respectively through digital interfaces. The pulse output terminal of the phase sequence measurement circuit 8 is connected to the MCU core control circuit 9, and the serial communication interface of the 4G communication circuit 10 is connected to the MCU core control circuit 9. The MCU core control circuit 9 collects and digitally processes the parameter signals and performs coordinated transmission.

[0036] The MCU core control circuit 9 uses a high-performance 32-bit microcontroller STM32F103C8T6 as the system's central processing unit, responsible for signal acquisition, digital conversion, algorithm calculation, and communication coordination.

[0037] The MCU core control circuit 9 is functionally connected to the output terminals of the current acquisition circuit 5, leakage current acquisition circuit 6, and voltage acquisition circuit 7 via multiple analog-to-digital interfaces. The current acquisition circuit 5 receives the current signal from the current transformer unit 51 via CT1_S1 and CT1_S2 inputs. After processing by the signal processing circuit composed of the operational amplifier unit 52, the signal is output from the A / D conversion input channel 91 and sent to the MCU core control circuit 9 for further processing to obtain the actual current value.

[0038] The leakage current acquisition circuit 6 is input through CT2_S1 and CT2_S2 of the leakage current mutual inductance unit 61. After passing through the signal processing circuit composed of the leakage current operational amplifier unit 62, the acquired leakage current signal is output through the leakage current conversion input channel 92, i.e., IK_ADC, and sent to the MCU core control circuit 9 for processing. The leakage current acquisition circuit 6 has higher sensitivity than the current acquisition circuit 5 and is better at monitoring small current signals.

[0039] In voltage acquisition circuit 7, the 220V voltage is input from L-N and attenuated by a resistor divider network 71 composed of resistors such as R17. After being isolated and amplified by opto-isolated operational amplifier unit 72, it is output from voltage conversion input channel 93 and sent to the A / D converter of the MCU for processing to obtain the actual voltage value.

[0040] The phase sequence measurement circuit 8 includes a zero-crossing detection sub-circuit composed of an isolated analog voltage comparison unit 81, which can achieve full isolation from 220V AC power. The phase sequence measurement circuit 8 is connected to the timer capture pin function of the MCU core control circuit 9 through the pulse output interface to generate a precise pulse signal at the zero-crossing point of the AC voltage.

[0041] The serial communication interface of the 4G communication circuit 10 is connected to the MCU core control circuit 9. The MCU core control circuit 9 collects and digitally processes the parameter signals and performs coordinated transmission.

[0042] As one embodiment provided, such as Figures 1-10 , This embodiment further discloses a monitoring method based on Embodiments 1 and 2. The method uses a power line loss anomaly monitoring system as its architecture for monitoring, and elaborates on the synchronous acquisition, transmission, and comparison process for phase sequence determination, as well as the calculation, threshold comparison, and determination process for line loss anomaly analysis. This enables real-time monitoring and anomaly diagnosis of the low-voltage distribution area power system, ensuring accurate phase sequence attribution and precise location of line loss problems.

[0043] The first step is synchronous clock initialization and reference signal acquisition. After system startup, host 1 and each sub-unit 2 acquire a unified reference clock pulse signal through communication module 3. The signal generates a rising edge every second, serving as the time reference for all nodes. The core control circuit of host 1 captures this pulse through a dedicated pin and broadcasts a synchronization command to each sub-unit 2, ensuring that the entire system operates under the same time reference. This step ensures global consistency in phase sequence determination, avoiding timing errors caused by network latency or local crystal oscillator deviation.

[0044] Next, the host unit 1 and the sub-unit 2 capture the zero-crossing pulse time interval. Based on the A phase sequence of the host unit 1, the host unit 1 and each sub-unit 2 capture the zero-crossing pulse time interval of their respective phase sequence.

[0045] Upon receiving the rising edge of the reference clock pulse, host 1 immediately starts its internal timer to begin timing. The phase sequence measurement circuit generates zero-crossing pulses for phases A, B, and C, and the core control circuit captures the rising edge timestamps of these pulses.

[0046] Assuming the grid frequency is 50 Hz, the host records the interval between the zero-crossing pulse of phase A and the reference pulse as 1 ms (phase A time), the interval for phase B as 7.66 ms (phase B time), and the interval for phase C as 14.33 ms (phase C time). These time intervals are recorded and stored in the memory of the core control circuit as a reference for phase sequence determination.

[0047] Each sub-unit 2 uses the same reference clock pulse signal as the main unit 1 as its synchronization clock. Upon receiving the rising edge of the pulse, it also starts its internal timer to capture the time interval between the rising edges of the zero-crossing pulses of its respective connected phase sequence. Sub-unit 2 is connected to phase A, with a capture interval of approximately 1ms; sub-unit 2 is connected to phase B, with a capture interval of approximately 7.66ms; and sub-unit 2 is connected to phase C, with a capture interval of approximately 14.33ms.

[0048] The three-phase extension unit 2 captures the intervals of phases A, B, and C respectively. Extension unit 2 records these intervals through the timer module of the core control circuit and packages the time intervals into data packets, including the identifier of extension unit 2 and the capture timestamp, etc., and transmits them to the host unit 1 in real time via the 4G wireless link of the communication module 3, supporting distributed phase sequence synchronization judgment.

[0049] The host unit 1 performs time interval comparison and phase sequence determination. After receiving the time intervals transmitted by each sub-unit 2, the host unit 1 executes a comparison algorithm through its core control circuit. The host unit 1 compares the time intervals of each sub-unit 2 with the A-phase time of 1ms, B-phase time of 7.66ms, and C-phase time of 14.33ms recorded by the host unit 1 one by one. A pre-set tolerance range is used for similarity judgment. The tolerance can be set to ±0.5ms based on the periodic characteristics of the 50Hz power grid frequency to compensate for interference and errors.

[0050] Let extension 2 be extension i, and the time interval be T_i. If the absolute value of the difference between T_i and the time of phase A is less than or equal to 0.5ms, then extension 2 is determined to be phase A. Similarly, it can be determined to be phase B or phase C. If a mismatch occurs, the signal re-acquisition process is triggered.

[0051] Finally, based on the phase sequence and the line loss anomaly analysis and judgment of the collected data, the host 1 integrates the determined phase sequence information, as well as the current, voltage, power and leakage current data collected from the host 1 and the sub-unit 2, and performs line loss anomaly analysis in the core control circuit.

[0052] The data is grouped according to the phase sequence. The current and voltage data of all A-phase units are summarized. The total branch power of A-phase is calculated as the sum of the current, voltage and power factor of each branch. The power factor is estimated by the phase difference between voltage and current. The total branch power of B-phase and C-phase is calculated in the same way.

[0053] The total power of the main unit is calculated as the power of phase A + the power of phase B + the power of phase C. The power of each phase is the corresponding current multiplied by the voltage multiplied by the power factor. The difference between the total power and the sum of the power of each branch is calculated. At the same time, the cumulative difference between the total current and voltage and the current and voltage of each branch is calculated, including the total current minus the sum of the currents of all branches, and the average value of the total voltage minus the average value of the branch voltage.

[0054] Set a difference threshold and compare the cumulative difference with the threshold: if the cumulative difference is greater than the threshold, it is determined to be an abnormal line loss. Further analyze the cause, integrate the total leakage current and the leakage current of each branch. If the sum of the leakage current of each branch is greater than the leakage current threshold, it may be caused by leakage.

[0055] If the power difference is concentrated in a certain phase, it may be due to electricity theft or metering failure.

[0056] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A power line loss anomaly monitoring system, characterized in that: include, Both the main unit (1) and the extension unit (2) are equipped with a communication module (3), which provides a wireless communication link and pulse signal; The main unit (1) and the sub-unit (2) are internally equipped with a power supply circuit (4), a current acquisition circuit (5), a leakage current acquisition circuit (6), a voltage acquisition circuit (7), a phase sequence measurement circuit (8), an MCU core control circuit (9), and a 4G communication circuit (10). The host (1) collects the current, voltage and leakage current parameters of the main line and establishes data interaction with the extension (2) using the communication module (3); The host (1) receives the parameters reported by the sub-unit (2) and performs line loss anomaly analysis and judgment.

2. The power line loss anomaly monitoring system according to claim 1, characterized in that: The MCU core control circuit (9) is connected to the output terminals of the current acquisition circuit (5), leakage current acquisition circuit (6), and voltage acquisition circuit (7) respectively through digital interfaces; The pulse output terminal of the phase sequence measurement circuit (8) is connected to the MCU core control circuit (9), and the serial communication interface of the 4G communication circuit (10) is connected to the MCU core control circuit (9). The MCU core control circuit (9) collects and digitally processes the parameter signals and performs coordinated transmission.

3. The power line loss anomaly monitoring system according to claim 1, characterized in that: The current acquisition circuit (5) includes a current transformer unit (51) and an operational amplifier unit (52); The current transformer unit (51) is connected to the A / D conversion input channel (91) of the MCU core control circuit (9) through the operational amplifier unit (52) to perform non-contact sampling of the line current.

4. The power line loss anomaly monitoring system according to any one of claims 1 to 3, characterized in that: The leakage current acquisition circuit (6) includes a leakage current mutual inductance unit (61) and a leakage current operational amplifier unit (62). The leakage current transformer unit (61) is functionally connected to the leakage current conversion input channel (92) of the MCU core control circuit (9) through the optimized sampling resistor network, so as to realize early warning of leakage fault; The voltage acquisition circuit (7) includes a resistor divider network (71) and an opto-isolated operational amplifier unit (72); The resistor divider network (71) is connected to the voltage conversion input channel (93) of the MCU core control circuit (9) through the opto-isolated operational amplifier unit (72) to achieve electrical isolation and signal amplification processing of high voltage AC voltage.

5. The power line loss anomaly monitoring system according to claim 4, characterized in that: The phase sequence measurement circuit (8) includes a zero-crossing detection sub-circuit composed of an isolated analog voltage comparison unit (81), which adopts optocoupler isolation to achieve full electrical isolation from the 220V AC power supply; The phase sequence measurement circuit (8) is connected to the timer capture pin function of the MCU core control circuit (9) through the pulse output interface to generate a precise pulse signal at the zero crossing point of the AC voltage.

6. A monitoring method, characterized in that, The system includes the power line loss anomaly monitoring system as described in claim 5, and includes the following steps: The reference clock pulse signal provided by the Beidou time synchronization + communication module (3) is used as the synchronization clock; The host (1) and each sub-unit (2) respectively capture the zero-crossing pulse time interval of their respective phase sequence, and each sub-unit (2) transmits the time interval to the host (1). The host (1) compares the time interval of each extension (2) with the time interval recorded by the host (1) to determine the phase sequence; Based on the phase sequence determination and the collected current, voltage, power, and leakage current data, anomaly analysis and judgment of line loss are performed.

7. The monitoring method according to claim 6, characterized in that: Each sub-unit (2) uses the same reference clock pulse signal as the main unit (1) as a synchronization clock. After receiving the rising edge of the reference clock pulse, it starts the internal timer to time and captures the time interval of the rising edge of the zero-crossing pulse of its respective connection phase sequence. The extension unit (2) records the time interval through the timer module of the MCU core control circuit (9) and packages the time intervals. It then transmits the data to the host in real time using the communication module (3), supporting distributed phase sequence synchronization judgment.

8. The monitoring method according to claim 7, characterized in that: The host (1) performs time interval comparison through the corresponding MCU core control circuit (9), and compares the time interval transmitted by the sub-unit (2) with the A, B, and C phase times recorded by the host one by one; Set a preset tolerance range for similarity assessment; If the time interval difference between the extension unit (2) and the phase sequence of the main unit (1) is within the tolerance range, then the extension unit is determined to be the corresponding phase sequence.

9. The monitoring method according to claim 8, characterized in that: The host (1) performs line loss anomaly analysis and judgment through the corresponding MCU core control circuit (9); Based on the determined phase sequence, the power value of each phase sequence is calculated from the collected current and voltage data. The total power is compared with the sum of the power of each branch, and the cumulative difference between the total current and voltage and the current and voltage of each branch is calculated. Set a difference threshold and compare the cumulative difference with the difference threshold; If the difference exceeds the threshold, it is determined to be an abnormal line loss; If the difference threshold is not exceeded, the line loss is considered normal.

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