Secondary circuit voltage drop 24-hour uninterrupted electric energy monitoring method

Abstract

The invention discloses a 24-hour uninterrupted electric energy monitoring method for secondary circuit voltage drop, relates to the technical field of electric energy metering, and solves the problems that errors exist in electric energy metering and fault early warning and positioning are not timely. The method comprises the following steps: 1, carrying out on-site investigation on a monitoring position, and determining the position and the number of monitoring points; 2, carrying out 24-hour uninterrupted on-line real-time metering or detection on a detected point by arranging an abnormal mode self-identification module; 3, electric energy data of the electric power system is monitored in real time through a secondary circuit electric energy monitoring module, and the secondary circuit electric energy monitoring module comprises the steps that 4, voltage and current signals output by a monitoring point are collected through an LoRa / NB-IoT module, the monitored data information is transmitted to a monitoring center or a cloud platform in real time at a transmission interval less than or equal to 1 minute; according to the invention, the electric energy monitoring capability is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy metering, and more particularly to a method for continuously monitoring the electric energy of the secondary circuit voltage drop for 24 hours. Background Art

[0002] The secondary voltage circuit is a key part of the power system for transmitting and measuring voltage signals. Its main function is to convert the high-voltage signal of primary equipment into a low-voltage signal suitable for protection devices and measuring instruments by a voltage transformer. This circuit consists of the secondary winding of the voltage transformer, secondary cables, protection devices, etc. Among them, the primary winding of the voltage transformer is connected to the high-voltage power grid, the secondary winding outputs a low-voltage signal to the secondary circuit, and is transmitted to the protection devices and instruments through cables to achieve real-time monitoring of the power grid status and fault response. As the core of the protection system, its reliability and accuracy directly affect the performance of the protection device and the safety of the power system. Therefore, how to achieve continuous monitoring of the electric energy of the secondary circuit voltage drop for 24 hours has become an urgent technical problem to be solved.

[0003] Traditional electric energy monitoring methods use regular inspections or manual meter reading, resulting in a long monitoring period and being unable to reflect the operating conditions of the power system in real time. Due to backward monitoring means and scattered monitoring points, the management department cannot timely understand the power quality levels of different regions and voltage levels, so it cannot take corresponding measures to improve power quality in a timely manner, nor can it form an efficient power quality supervision and management system. Traditional electric energy monitoring methods lack perfect data security protection measures, there is a risk of data leakage, involve user privacy information during the monitoring process, and the ability to continuously monitor the electric energy of the secondary circuit voltage drop for 24 hours lags behind. Summary of the Invention

[0004] In view of the above deficiencies in the technology, the present invention discloses a method for continuously monitoring the electric energy of the secondary circuit voltage drop for 24 hours, which can capture the dynamic changes of the power system in real time, including minute fluctuations in parameters such as voltage and current, and provide accurate and reliable electric energy data through high-precision sensors and advanced data processing technologies. By using automated monitoring equipment and technologies, it can automatically collect, process, and analyze electric energy data, reduce manual intervention, and improve the ability to continuously monitor the electric energy of the secondary circuit voltage drop for 24 hours.

[0005] A method for continuously monitoring the electric energy of the secondary circuit voltage drop for 24 hours, which includes the following steps: Step 1. Conduct on-site inspection of the monitoring location to determine the positions and quantities of the monitoring points, install a current sensor with an accuracy of ±0.1% and a voltage sensor with an accuracy of ±0.05%, set a measurement band of 50Hz - 1kHz to monitor the voltage and current signals in the secondary circuit in real time; achieve synchronous sampling of the master and slave sensors through a GPS timing module with an accuracy of 0.5μs to ensure the time alignment of the voltage / current waveforms; Step 2. Continuously and real-time measure or detect the measured point 24 hours a day through the set abnormal mode self-identification module, use the current zero-crossing signal in the secondary circuit as the synchronization source, and achieve full-cycle synchronization of the master and slave devices through the two-way handshake protocol; improve the detection range through the threshold dynamic adjustment module; Step 3. Continuously monitor the electrical energy data of the power system through the secondary circuit electrical energy monitoring module, and the secondary circuit electrical energy monitoring module includes: A blockchain module based on the SE050 security chip and an electrical energy loss calculation module, a measurement loop error calculation module, a secondary circuit voltage drop compensation module, and a voltage drop comparison module connected to the blockchain module; Step 4. Collect the voltage and current signals output by the monitoring points through the LoRa / NB-IoT module, and transmit the monitored data information to the monitoring center or cloud platform in real time with a transmission interval of ≤1 minute; when a hardware or software failure occurs, automatically switch to the standby system to ensure continuous monitoring for 24 hours.

[0006] As a further technical solution of the present invention, In the step 1, the monitoring point positions are set at the secondary side of the voltage transformer, the input end of the electric energy meter, and the key nodes at both ends of the coil of the important relay that have a great influence on the voltage drop, and monitoring points are set at different positions of the circuit to ensure that the voltage drop situation of the entire circuit can be comprehensively reflected; the number of monitoring points is in a proportional relationship with the complexity and length of the secondary circuit, and the number of monitoring points is limited considering the cost.

[0007] As a further technical solution of the present invention, In the step 1, the voltage sensor is installed at the output end of the secondary side of the voltage transformer or the input end of the electric energy meter, and the current sensor is installed at the output end of the secondary side of the current transformer or on the conductor directly connected to the current path in the secondary circuit, and directly measured using a voltage drop tester for the secondary circuit of the voltage transformer. The tester checks the correctness of the wiring, extracts the voltage drop signal after isolation, and displays the amplitude error and phase error of the secondary voltage drop.

[0008] As a further technical solution of the present invention, In the step 2, the working method of the abnormal mode self-identification module is: The DSP digital signal processor is used to detect voltage, voltage drop value, device status code, current, ripple, magnetic field or vibration data information. The environmental data influence amount, real-time data stream of historical data and different types of data information are set through dynamic thresholds. The sampling frequency is dynamically adjusted by the electromagnetic field intensity sensor to suppress interference, and the timing information error is <0.45 μs. The 1:2 isolation transformer is used to avoid electromagnetic coupling interference. The distortion rate of the time-domain waveform, spectral entropy and time-frequency characteristics are extracted. The dynamic threshold module automatically adjusts the alarm threshold according to the environmental temperature and humidity or load changes to avoid false alarms of fixed thresholds. The master device triggers sampling through the current zero-crossing signal, and the slave device realizes full-cycle synchronization after response confirmation. When the abnormal probability exceeds the threshold, an alarm is triggered, the abnormal waveform is recorded, and the circuit breaker works.

[0009] As a further technical solution of the present invention, The electric energy loss calculation module includes a Kalman filter calculation module, a voltage drop calculation circuit module, a parallel data channel module, a constant current source differential amplifier circuit module and a waveform distortion calculation module. The output end of the Kalman filter calculation module is connected to the input end of the voltage drop calculation circuit module, the output end of the voltage drop calculation circuit module is connected to the input end of the parallel data channel module, the output end of the parallel data channel module is connected to the input end of the constant current source differential amplifier circuit module, and the output end of the constant current source differential amplifier circuit module is connected to the input end of the waveform distortion calculation module. The voltage drop calculation circuit module includes a current detection circuit, a differential calculation circuit, a rectification control circuit and a short-circuit protection circuit. The output end of the current detection circuit is connected to the input end of the differential calculation circuit, the output end of the differential calculation circuit is connected to the input end of the rectification control circuit, and the output end of the rectification control circuit is connected to the input end of the short-circuit protection circuit.

[0010] As a further technical solution of the present invention, The measurement loop error calculation module at least includes a power measurement error calculation module, a timing measurement error calculation module, a frequency measurement error calculation module or a pulse measurement error calculation module; The secondary loop voltage drop compensation module includes amplitude compensation, phase compensation or dynamic compensation of the secondary loop based on the change of load current. The working method of the secondary loop voltage drop compensation module: In the electric energy metering, an electric energy metering instrument with a relative error not exceeding ±0.1% is selected to meet the requirements of high-precision measurement. An instrument using the sliding sampling method is adopted to reduce the measurement error caused by the secondary loop voltage drop. At the same time, amplitude compensation, phase compensation or dynamic compensation of the secondary loop based on the change of load current is selected, and the average response time responds to the change of electricity within three seconds. The compensation method is selected according to the load compensation type to ensure the real-time and accuracy of metering. As a further technical solution of the present invention, The pressure drop comparison module dynamically adjusts the threshold dynamic threshold comparison according to real-time load current, voltage, ripple, magnetic field, vibration, load or temperature parameters; The working method for real-time monitoring of voltage and current signals in the secondary circuit is as follows: The voltage and current in the secondary circuit are converted into electrical signals through sensors, the signals output by the sensors are amplified through a signal amplification circuit, and the signals are filtered and denoised through a signal conditioning circuit to improve the accuracy and stability of the signals. The processed analog signals are sent to an analog-to-digital converter to convert the analog signals into digital signals with higher anti-interference ability and transmission efficiency. The collected digital signals are temporarily stored in the memory of the data acquisition module, and the data is preprocessed to reduce the bandwidth and storage space occupied by data transmission; Then, the collected data is encapsulated. The encapsulation content includes at least information such as adding a data header and a check code. According to the requirements of the monitoring center or cloud platform, the Modbus protocol, 485 communication protocol or blockchain communication protocol is selected for data transmission. The data is converted into binary or hexadecimal codes in a specific format. The encapsulated and format-converted data is transmitted to the monitoring center or cloud platform in real time through a wired / wireless network. During the transmission process, the data is forwarded and routed through multiple relay nodes or routers. After receiving the data, the monitoring center or cloud platform performs data reception and confirmation operations. If the data is lost or incorrect, the system performs retransmission or alarm processing.

[0011] As a further technical solution of the present invention, The working principle of the pressure drop calculation circuit module is as follows: By collecting the secondary-side signals of voltage transformers and current transformers, as well as the output signals of electric energy meters for real-time processing and analysis, the pressure drop situation and the change of electric energy in the secondary circuit are monitored. The secondary circuit electric energy monitoring module obtains the actual operating state of the power system by collecting the secondary-side voltage and current signals of voltage transformers and current transformers through the data acquisition module. The secondary circuit electric energy monitoring module collects the output signals of electric energy meters, including at least pulse signals or digital signals, to obtain real-time data of electric energy. The collected voltage and current signals first pass through a signal conversion and amplification circuit to be converted into a level range for subsequent processing, and filtering technology is used for processing to ensure the accuracy of the data. The filtered signals are sent to an analog-to-digital converter to convert the analog signals into digital signals. The processed data is further processed and analyzed by using Fourier transform for the digital signals to extract useful information; According to the preprocessed data, complex numbers are used to represent current, voltage, and impedance, and calculations are performed through phasor analysis. The calculation formula for current is: In formula (1), represents voltage, and the complex representation of voltage is Z represents impedance, and the complex representation of impedance is , where R represents resistance, j represents the imaginary unit, X represents reactance, F represents the error factor affected by current, and the calculation formula for voltage drop is: In formula (2), K represents the proportionality coefficient, represents the voltage drop across the resistor R. Simplify the formula using polar coordinates. The formula under ideal conditions is: In formula (3), represents the magnitude of the impedance of resistor R, represents the phase angle of the current phasor, represents the phase angle of the impedance phasor. After obtaining the voltage drop according to the formula, the magnitude and phase angle are obtained. The calculation formula for the phase difference is: In formula (4), represents the phase difference, represents the angular frequency and represents the reflection coefficient. The formula for the reflection coefficient is: In formula (5), is the characteristic impedance of the transmission line. The specific phase difference change is obtained by changing the phase change of the signal according to the phase part of the reflection coefficient r.

[0012] As a further technical solution of the present invention, The working principle of the short - circuit protection circuit is as follows: By adding additional monitoring channels or sensors to monitor the voltage drop situation of the secondary circuit in real - time. When a certain monitoring channel fails, other channels can still continue to work to ensure the continuity and accuracy of the monitoring data. A data acquisition module, a communication module, a control module, and a power supply module are used to build the system. When a certain hardware component fails, it automatically switches to the standby component through a relay circuit to ensure the normal operation of the system; The working principle of the automatic switching of the relay circuit is: When a certain component fails, the alarm module immediately issues an alarm and starts the fault - switching program. According to the type and severity of the fault, the system makes a switching decision, and realizes information switching by methods such as shutting down the faulty component, starting the standby component, or re - configuring the system. If the verification fails, the switching instruction is re - initiated.

[0013] The present invention also adopts the following technical solution: A 24 - hour uninterrupted power energy monitoring system for the voltage drop of the secondary circuit, which applies one of the above - mentioned technical solutions of a 24 - hour uninterrupted power energy monitoring method for the voltage drop of the secondary circuit.

[0014] Positive and beneficial effects The 24-hour uninterrupted monitoring of the secondary circuit voltage drop can capture the minute changes in parameters such as voltage and current in real time, thus more accurately reflecting the actual operating conditions of the power system. Through the analysis of the monitoring data, potential faults in the power system can be detected in a timely manner, and early warning signals can be sent out, winning precious time for fault handling. Through real-time monitoring and analysis, the fault point can be quickly located, and effective measures can be taken for fault handling to reduce the impact of the fault on the power system. The secondary circuit voltage drop monitoring method can accurately reflect the actual power consumption, providing reliable data support for power metering. By monitoring the power consumption in real time, accurate calculation and reasonable allocation of electricity charges can be achieved, improving the fairness and transparency of billing management. The secondary circuit voltage drop monitoring method uses advanced sensors and data processing technologies to achieve intelligent monitoring and management of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, where: Figure 1 It is a schematic flowchart of the method of the present invention; Figure 2 It is a schematic diagram of the principle of the secondary circuit electrical energy monitoring module in the present invention; Figure 3 It is a schematic diagram of the principle of the electrical energy loss calculation module in the present invention; Figure 4 It is a schematic diagram of the principle of the differential calculation circuit in the present invention; Figure 5 It is a schematic diagram of the principle of the current detection circuit in the present invention; Figure 6 It is a schematic diagram of the principle of the short-circuit protection circuit in the present invention; Figure 7 It is a schematic diagram of the principle of the constant current source differential amplifier circuit module in the present invention; Figure 8 It is a circuit diagram of an embodiment of the operational amplifier in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will describe the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0017] As Figures 1 - 8 shown, a 24-hour uninterrupted electrical energy monitoring method for the secondary circuit voltage drop is characterized in that it includes the following steps: Step 1: Conduct on-site investigation of the monitoring location, determine the location and quantity of the monitoring points, install a current sensor with an accuracy of ±0.1% and a voltage sensor with an accuracy of ±0.05%, set a measurement frequency band of 50Hz - 1kHz to monitor the voltage and current signals in the secondary circuit in real time; achieve synchronous sampling of the master and slave sensors through a GPS timing module with an accuracy of 0.5μs to ensure the time alignment of the voltage / current waveforms; Step 2: Continuously and real-time measure or detect the measured point online for 24 hours through the set abnormal mode self-identification module, use the current zero-crossing signal in the secondary circuit as the synchronization source, and achieve full-cycle synchronization of the master and slave devices through the two-way handshake protocol; improve the detection range through the threshold dynamic adjustment module; Step 3: Real-time monitor the electrical energy data of the power system through the secondary circuit electrical energy monitoring module, and the secondary circuit electrical energy monitoring module includes: A blockchain module based on the SE050 security chip and an electrical energy loss calculation module, a measurement loop error calculation module, a secondary circuit voltage drop compensation module, and a voltage drop comparison module connected to the blockchain module; Step 4: Collect the voltage and current signals output by the monitoring points through the LoRa / NB-IoT module, and transmit the monitored data information to the monitoring center or cloud platform in real time with a transmission interval of ≤1 minute; when a hardware or software failure occurs, automatically switch to the standby system to ensure 24-hour uninterrupted monitoring.

[0018] In the above Step 1, the monitoring point positions are set at the secondary side of the voltage transformer, the input end of the watt-hour meter, and the key nodes at both ends of the coil of important relays that have a great impact on the voltage drop. Monitoring points are set at different positions in the circuit to ensure that the voltage drop situation of the entire circuit can be comprehensively reflected; the number of monitoring points is in a proportional relationship with the complexity and length of the secondary circuit, and the number of monitoring points is limited considering the cost.

[0019] In the above Step 1, the voltage sensor is installed at the output end of the secondary side of the voltage transformer or the input end of the watt-hour meter, and the current sensor is installed at the output end of the secondary side of the current transformer or on the conductor directly connected to the current path in the secondary circuit. Use a voltage drop tester for the secondary circuit of the voltage transformer to directly measure. The tester checks the correctness of the wiring, extracts the voltage drop signal after isolation, and displays the amplitude error and phase error of the secondary voltage drop.

[0020] Further, in the above embodiments, the monitoring point positions are set at the secondary side of the voltage transformer, the input end of the watt-hour meter, and the two ends of the coil of important relays to monitor the key nodes that have a great impact on the voltage drop. Monitoring points are set at different positions of the circuit to ensure that the voltage drop situation of the entire circuit can be comprehensively reflected. The number of monitoring points is in a proportional relationship with the complexity and length of the secondary circuit, and the number of monitoring points is limited considering the cost.

[0021] In a specific embodiment, determine the types of energy metering devices to be monitored, the distribution of energy metering devices, and the routing of the secondary circuit. Select a suitable secondary voltage drop tester to ensure that the device accuracy meets the requirements and has data storage and remote transmission functions. Determine the monitoring time period to ensure that 24-hour uninterrupted monitoring can be covered. According to the distribution of energy metering devices and the routing of the secondary circuit, select the secondary side of the voltage transformer, the watt-hour meter side, and the intermediate connection point as monitoring points to ensure that the monitoring point positions are safe and reliable, away from interference sources such as high temperature, humidity, and strong magnetic fields. Consider the accessibility of the monitoring points to facilitate operation and maintenance by monitoring personnel. Conduct on-site surveys on the selected monitoring points to confirm whether the positions are appropriate, and check the electrical environment around the monitoring points to ensure that they will not interfere with the monitoring equipment. Determine the number of monitoring points according to the number and distribution of energy metering devices and the complexity of the secondary circuit to ensure that each important energy metering device and secondary circuit node is covered by a monitoring point. On the premise of meeting the monitoring requirements, reasonably control the number of monitoring points to reduce the monitoring cost, optimize the layout of the monitoring points to ensure that the monitoring data can comprehensively and accurately reflect the voltage drop situation of the secondary circuit. Connect the monitoring equipment to the selected monitoring points according to the monitoring plan to ensure that the connection is firm and reliable, and avoid measurement errors caused by poor contact or looseness. Set the parameters of the monitoring equipment, such as the measurement range and sampling frequency, according to the monitoring requirements to ensure that the parameter settings are correct to guarantee the accuracy and reliability of the monitoring data. After confirming that the monitoring equipment is working properly, start the monitoring program to collect, store, and transmit the monitoring data in real time to ensure the integrity and timeliness of the data. Analyze and process the monitoring data, calculate parameters such as the relative value of the secondary circuit voltage drop. According to the analysis results, judge whether the secondary circuit voltage drop meets the requirements and propose corresponding improvement measures. An example of the monitoring data is shown in Table 1: In Table 1, the time represents the monitoring time point, expressed in 24-hour format. Phase voltages A, B, and C: respectively represent the values of the three-phase voltages, with the unit of volt (V). Voltage drops A, B, and C: respectively represent the voltage drops of the three-phase voltages in the secondary circuit, with the unit of volt (V). The voltage drop can be calculated by comparing the voltage at the outlet side of the voltage transformer and the voltage at the watt-hour meter side. The electrical energy loss represents the percentage of electrical energy loss caused by the secondary circuit voltage drop, and this value can be estimated based on the magnitude of the voltage drop and the magnitude of the current.

[0022] Furthermore, the voltage sensor is installed at the output end of the secondary side of the voltage transformer or at the input end of the watt-hour meter, and the current sensor is installed at the output end of the secondary side of the current transformer or on a conductor directly connected to the current path in the secondary circuit. A special voltage drop tester for the secondary circuit of the voltage transformer is used for direct measurement. The tester checks the correctness of the wiring, extracts the voltage drop signal after isolation, and displays the amplitude error and phase error of the secondary voltage drop.

[0023] In a specific embodiment, according to the monitoring requirements, voltage and current sensors with high precision, high stability, low drift, and low noise characteristics are selected. The sensors should have good anti-interference capabilities and be able to work stably in a complex electromagnetic environment. According to the complexity of the secondary circuit and the number of monitoring points, the number of sensors is reasonably configured to ensure that each key monitoring point has corresponding voltage and current sensors for real-time monitoring. A suitable installation location is selected to ensure that the sensors can accurately measure the voltage and current signals in the secondary circuit, and the sensors are avoided to be installed in harsh environments such as vibration and shock, so as not to affect the measurement accuracy and stability. According to the wiring requirements of the sensors, the voltage and current signal lines are correctly connected to ensure that the wiring is firm and reliable, and measurement errors caused by poor contact or looseness are avoided. Anti-interference measures such as shielded wires or coaxial cables are used to reduce the influence of external interference on the measurement results.

[0024] Furthermore, in electric energy metering, a watt-hour metering instrument with a relative error not exceeding ±0.1% is selected to meet the requirements of high-precision measurement. An instrument using the sliding sampling method is adopted to reduce the measurement error caused by the voltage drop in the secondary circuit. At the same time, a measurement instrument with high stability is selected, and the average response time is three seconds or shorter to respond to the change of electric energy in a timely manner, ensuring the real-time and accuracy of metering. In a specific embodiment, according to the monitoring requirements, a suitable type of watt-hour metering instrument is selected, including a fully automatic secondary voltage drop measuring instrument, a secondary voltage drop and load tester, etc. These instruments can accurately measure the error caused by the voltage drop in the secondary circuit of the voltage transformer and have functions such as data storage and transmission. A high-precision watt-hour metering instrument is selected to ensure the accuracy of the measurement results. The accuracy of the watt-hour metering instrument should reach 0.5 level or higher to meet the accuracy requirements of secondary circuit voltage drop monitoring. The instrument has good stability and reliability and can maintain the accuracy of the measurement results during long-term continuous monitoring. The high-precision watt-hour metering instrument is installed at the key position of the secondary circuit of the voltage transformer to ensure that the secondary circuit voltage drop can be accurately measured. Wiring and calibration are carried out according to the requirements of the instrument instruction manual to ensure the accuracy of the measurement results. During the wiring process, pay attention to avoiding problems such as wiring errors or poor contact, so as not to affect the measurement results. After the instrument is installed, debugging and testing are carried out to ensure that the instrument can work normally and meet the measurement requirements.

[0025] Furthermore, the working principle of the data acquisition module is as follows: The sensor converts the voltage and current in the secondary circuit into electrical signals. The signal amplification circuit in the data acquisition module amplifies the signals output by the sensor. At the same time, the signal conditioning circuit filters and denoises the signals to improve the accuracy and stability of the signals. The processed analog signals are sent to the analog-to-digital converter to convert the analog signals into digital signals with higher anti-interference ability and transmission efficiency. The collected digital signals are temporarily stored in the memory of the data acquisition module, and the data is preprocessed to reduce the bandwidth occupied by data transmission and the storage space. The working principle of the data transmission module is as follows: The data transmission module encapsulates the collected data, including at least adding information such as data headers and check codes to ensure the integrity and accuracy of the data. According to the requirements of the monitoring center or cloud platform, the data transmission module selects the Modbus protocol for data transmission. The data module converts the data into binary or hexadecimal codes in a specific format. The encapsulated and format-converted data is transmitted to the monitoring center or cloud platform in real time through a wired / wireless network. During the transmission process, the data is forwarded and routed through multiple relay nodes or routers. After receiving the data, the monitoring center or cloud platform performs data reception and confirmation operations. If data is lost or incorrect, the system performs retransmission or alarm processing.

[0026] In a specific embodiment, the main task of the data acquisition module is to collect the electrical energy data in the secondary circuit in real time and accurately. It is required to select voltage and current sensors with high precision to ensure the accuracy of the collected data. The sensors are required to work stably for a long time and have strong adaptability to external factors such as environmental temperature and humidity. The sampling circuit should be able to accurately convert the analog signals output by the sensor into digital signals. During the sampling process, the integrity of the signals should be ensured to avoid signal distortion or loss. The data acquisition module should be able to collect the electrical energy data in the secondary circuit in real time, including key parameters such as voltage, current, and power factor. To achieve real-time performance, a high-speed microprocessor or a dedicated data acquisition chip is used to ensure that the data acquisition speed meets the system requirements. During the data acquisition process, the original data should be preprocessed, including steps such as filtering, denoising, and calibration, to improve the accuracy and reliability of the data.

[0027] The main task of the data transmission module is to transmit the data collected by the data acquisition module to the monitoring center or the host computer in real time for further processing and analysis. It uses a standard communication protocol for data transmission to ensure the stability and reliability of the data transmission process, with good compatibility and scalability to meet the requirements of different systems. The communication circuit supports high-speed and stable data transmission. It can adopt wired communication or wireless communication methods, and select the appropriate communication method according to the specific application scenario. During the data transmission process, in order to save bandwidth and improve transmission efficiency, the data can be compressed. At the same time, in order to ensure the security of the data, encryption technology should be used to encrypt the data during transmission to prevent the data from being stolen or tampered with. In order to improve the reliability of data transmission, a redundancy and fault tolerance mechanism can be designed. For example, dual-channel communication, data retransmission, etc. are adopted to ensure that even in case of abnormal situations during the data transmission process, the data can be recovered in time and continue to be transmitted.

[0028] Further, the principle of the secondary circuit electric energy monitoring module is as follows: The secondary circuit electric energy monitoring module collects the secondary side signals of the voltage transformer and the current transformer, as well as the output signal of the electric energy meter for real-time processing and analysis, monitors the voltage drop situation and the change of electric energy in the secondary circuit. The secondary circuit electric energy monitoring module obtains the actual operating state of the power system by collecting the secondary side voltage and current signals of the voltage transformer and the current transformer through the data acquisition module. The secondary circuit electric energy monitoring module collects the output signal of the electric energy meter, which at least includes pulse signals or digital signals, to obtain real-time data of electric energy. The collected voltage and current signals first pass through a signal conversion and amplification circuit to be converted into a level range for subsequent processing, and are processed using filtering technology to ensure the accuracy of the data. The filtered signal is sent to an analog-to-digital converter to convert the analog signal into a digital signal, and the processed data is further processed and analyzed using Fourier transform on the digital signal to extract useful information; in a further embodiment, as Figure 2 shown Figure 2 in, the voltage secondary circuit of the electric energy metering starts from the potential transformer (PT), passes through fuses, PT secondary terminal boxes, terminal blocks, junction boxes, etc. until the electric energy meter. Detecting points are respectively set on both sides of these circuit components to make the fault detection of the voltage secondary circuit more accurate. However, due to the large number of circuit components and the high cost of setting multiple detecting points, in this paper, detecting points are respectively set at to set detecting points The detecting point is used to collect the output voltage value of the PT secondary terminal box; The detection points are used to collect the input voltage values of the terminal block and the junction box. The secondary circuit of the electric energy metering current starts from the current transformer (CT), passes through the CT secondary terminal box, the terminal block, the junction box, etc. until the watt-hour meter. At this point, detection points are set to collect the output current of the CT secondary terminal box and the input currents of the terminal block and the junction box respectively. By means of the detection points set in the secondary circuit, the detection of current, voltage and power in the secondary circuit can be realized, and compared with the parameter information in the normal line. Through the electric energy detection module of the secondary circuit, the detection of faults in the secondary circuit can be realized. In the second step, the working method of the abnormal mode self-identification module is as follows: Detect voltage, voltage drop value, device status code, current, ripple, magnetic field or vibration data information through a DSP digital signal processor. Set the influence amount of environmental data, the real-time data data stream of historical data and different types of data information through dynamic thresholds. Dynamically adjust the sampling frequency through an electromagnetic field intensity sensor to suppress interference. The timing information error < 0.45 μs. Avoid electromagnetic coupling interference through a 1:2 isolation transformer. Extract the time-domain waveform distortion rate, spectral entropy and time-frequency characteristics. The dynamic threshold module automatically adjusts the alarm threshold according to the ambient temperature and humidity or load changes to avoid false alarms of fixed thresholds. The master device triggers sampling through the current zero-crossing signal, and after the slave device responds and confirms, full-cycle synchronization is achieved; when the abnormal probability exceeds the threshold, an alarm is triggered and the abnormal waveform is recorded, and the circuit breaker works. In specific applications, the master device triggers sampling by detecting the current zero-crossing signal (Zero-Crossing) to ensure that the sampling starting point is strictly synchronized with the power grid cycle. After receiving the trigger signal from the master device, the slave device responds and confirms (ACK) and starts sampling to achieve full-cycle synchronization, and the timing error is controlled within < 0.45 μs (realized by a high-precision clock source such as GPS or an oven-controlled crystal oscillator). Use a 1:2 isolation transformer to isolate the electrical connection between the master and slave devices, blocking the ground loop current and electromagnetic coupling interference. Optical fiber or shielded twisted pair is used for signal transmission to reduce common-mode noise. When dynamically adjusting the sampling frequency, the sampling frequency can be dynamically switched according to the data of the electromagnetic field intensity sensor (for example, 50 kHz → 100 kHz) to avoid strong interference frequency bands. Real-time collect ambient temperature and humidity data, and correct the threshold through a pre-calibrated temperature and humidity-error curve (such as relaxing the vibration amplitude threshold at high temperatures) for environmental adaptive adjustment. Establish an association model between the load current and characteristic parameters (such as ripple amplitude), and the threshold is automatically adjusted according to the load change (for example, when the load increases, a higher instantaneous ripple value is allowed) for load correlation modeling. Use a sliding window to statistically calculate the mean and variance of the historical data stream (such as the last 100 cycles), and dynamically set the threshold interval: , where k is the environmental correction coefficient, and Δ environment is the temperature and humidity influence amount. Input waveform distortion rate, spectral entropy, time-frequency characteristics, etc. into the fuzzy logic or Bayesian network model in the DSP to calculate the comprehensive anomaly probability P anomaly. Assign dynamic weights to different characteristics, for example, the weight of high-frequency vibration anomaly is higher than that of low-frequency magnetic field fluctuation. Then adopt threshold trigger alarm. When a first-level alarm occurs, when P anomaly is greater than 75%, record the abnormal waveform and upload it to the monitoring system. When a second-level alarm occurs, when P anomaly is greater than 90%, trigger the circuit breaker to trip and start the standby power supply switching at the same time. The master device sends a trigger pulse containing a timestamp by receiving multi-channel sampling data (voltage, current, vibration, etc.) from the ADC. The slave device aligns the sampling window at the next zero crossing. Transmit the synchronization signal using RS-485 or CAN bus to ensure low latency (<10 μs), and automatically adjust the threshold and sampling strategy according to the environment / load change to reduce the false alarm rate. Zero trigger + master-slave cooperation ensures the phase consistency of the data. Joint analysis of time domain, frequency domain, and environmental parameters improves the sensitivity of anomaly detection. In the above embodiment, the electric energy loss calculation module includes a Kalman filter calculation module, a voltage drop calculation circuit module, a parallel data channel module, a constant current source differential amplifier circuit module, and a waveform distortion calculation module. The output end of the Kalman filter calculation module is connected to the input end of the voltage drop calculation circuit module, the output end of the voltage drop calculation circuit module is connected to the input end of the parallel data channel module, the output end of the parallel data channel module is connected to the input end of the constant current source differential amplifier circuit module, and the output end of the constant current source differential amplifier circuit module is connected to the input end of the waveform distortion calculation module. The voltage drop calculation circuit module includes a current detection circuit, a differential calculation circuit, a rectification control circuit, and a short-circuit protection circuit. The output end of the current detection circuit is connected to the input end of the differential calculation circuit, the output end of the differential calculation circuit is connected to the input end of the rectification control circuit, and the output end of the rectification control circuit is connected to the input end of the short-circuit protection circuit.

[0029] In the above embodiment, as Figure 4As shown, the differential amplifier circuit, as an important analog circuit, its core function is to amplify the difference between two input signals while effectively suppressing the common-mode signal. It usually consists of two symmetric amplifier circuits and a constant current source. When two input signals enter the non-inverting input terminal and the inverting input terminal of the differential amplifier circuit respectively, the circuit amplifies the difference between these two signals, and the amplitude of the output signal is proportional to the difference between the input signals. The reason why the differential amplifier circuit can suppress the common-mode signal is that the symmetry of the circuit makes the two amplifier circuits produce the same response to the common-mode signal, and the common-mode signal is cancelled after subtraction at the output terminal. This characteristic makes the differential amplifier circuit perform excellently in application scenarios that require high-precision signal processing and strong anti-interference ability, such as in sensor signal processing, audio amplification and other fields. The LM2596 circuit is a switching power supply chip circuit, mainly used to convert the input DC voltage into a stable output DC voltage. It works based on the pulse width modulation (PWM) technology. By periodically turning on and off the internal switching transistor, it controls the storage and release of energy, thus realizing the voltage conversion. The LM2596 chip integrates multiple functional modules such as an error amplifier, a PWM controller, and a switching transistor. When the input voltage and the load change, the error amplifier compares the output voltage with the internal reference voltage to generate an error signal. The PWM controller adjusts the on-time of the switching transistor, that is, the pulse width, according to this error signal, so that the output voltage can be kept stable. In a system that needs to amplify weak signals, first, the LM2596 circuit converts the unstable input power supply voltage into a stable DC voltage to provide a stable power supply for the whole system. Then, the differential amplifier circuit amplifies the weak signals from devices such as sensors. Due to the high precision and anti-interference ability of the differential amplifier circuit, it can ensure that, with the support of a stable power supply, the difference of the signals is accurately amplified, and external interference and common-mode noise are suppressed, thus providing high-quality signals for subsequent signal processing and analysis. In summary, the differential amplifier circuit focuses on signal difference amplification and common-mode suppression, while the LM2596 circuit is responsible for power conversion and stabilization. As Figure 5As shown, the potentiostat provides a stable bias voltage for the current detection resistor (shunt), ensuring a constant potential at the detection node. The output is adjusted in real time through a feedback loop to eliminate the influence of power supply fluctuations and environmental temperature drifts on the voltage across the detection resistor, improving the baseline stability. For example, in the 50A range, the potentiostat locks the voltage at the high end of the shunt at the 2.5V reference level to avoid common-mode interference. When converting the current / voltage signal, the measured current flows through a precision shunt resistor (such as 0.5mΩ / 0.1% manganese copper alloy), generating a millivolt-level voltage drop signal ΔV. The current / voltage conversion circuit uses a low-temperature-drift instrumentation amplifier (such as AD8421), sets the initial gain to 100 times, amplifies ΔV to the 0 - 5V range, and suppresses common-mode noise of >100dB at the same time. The microcontroller (such as STM32G4) controls the digital potentiometer (AD5172) through the I²C bus, and dynamically adjusts the gain of the amplifier circuit according to the signal amplitude. When it is detected that ΔV is lower than 10% of the range, the gain is increased to 500 times; when it is higher than 90%, it is automatically switched to 50 times to achieve a wide dynamic range (1mA - 100A) coverage. The amplified analog signal is sampled by a 24-bit Σ-Δ ADC (ADS1256) with a conversion rate of 1kSPS and an effective number of bits reaching 20 bits. The power calculation module synchronously collects the load voltage signal, and uses a hardware multiplier (MCU with built-in DSP) to perform real-time operation of the instantaneous power P(t)=I(t)×V(t), and the calculation period <10μs. The microcontroller monitors the RMS current and peak power through a sliding window algorithm. When continuous overload (such as I>120% of the rated value for 500ms) or instantaneous impact (di / dt>1A / μs) is detected, a three-level protection mechanism is triggered: Level 1: The digital potentiometer cuts into a parallel resistor to forcibly reduce the gain to avoid ADC saturation.

[0030] Level 2: Send a PWM signal to the relay drive circuit (opto-isolation + MOSFET array) to cut off the main circuit within 5ms.

[0031] Level 3: Start the backup power supply path to maintain the continuous operation of the control system.

[0032] When the system is powered on, zero calibration is automatically performed: short-circuit the input end of the detection resistor, and inject a compensation voltage through the DAC to eliminate the operational amplifier offset. During operation, the NTC temperature sensor is used to monitor the temperature rise of the shunt, and the resistance value is dynamically corrected according to the formula ΔR = α·R0·(T - T0) (α = 50ppm / ℃). Combined with the look-up table compensation algorithm of the microcontroller, the measurement error in the full temperature range (-40~+85℃) is ≤±0.05%. Through the closed-loop control, dynamic range switching and multi-level protection strategies, this architecture realizes current detection with an accuracy of ±0.1%FS in scenarios such as industrial frequency converters and new energy battery management, with a response time <10μs and an overload tolerance capacity reaching 20 times the rated value.

[0033] In the above embodiments, the current / voltage conversion circuit uses a shunt or a current transformer to convert the measured current signal (0 - 100A) into a millivolt-level voltage signal (such as 100mV@100A). The potentiostat provides a stable reference potential (±5V) for the conversion circuit to ensure the measurement accuracy of the potential difference across the shunt. The differential amplifier circuit performs common-mode rejection (CMRR≥100dB) on the converted voltage signal to suppress environmental noise. The digital potentiometer (such as X9C103) is dynamically adjusted by the microcontroller to change the amplification factor (10 - 1000 times) to achieve wide-range self-adaptation. The operational amplifier (such as OP07) constitutes a second-order active filter circuit with a cut-off frequency of 10kHz to filter out high-frequency interference. The microcontroller (such as STM32F4) has a built-in 12-bit ADC to sample the amplified voltage signal (0 - 3V) at a sampling rate of 10kHz. The power calculation module calculates the active power in real time , where the voltage signal is synchronously collected through a resistor voltage division network. The relay switch protection circuit monitors the current value in real time. When it exceeds the threshold (such as 110% of the rated current), the microcontroller triggers the relay (such as G6K-2F-Y) to cut off the main circuit, and the response time < 10ms. The potentiostat and the microcontroller form a closed-loop feedback, and the reference potential is dynamically adjusted through the PID algorithm to compensate for the temperature drift (ΔV / ΔT≤50μV / ℃). The digital potentiometer executes an automatic calibration program when the system is powered on, and adjusts the zero point and gain of the amplifier circuit by injecting a standard current (such as 10A). The microcontroller stores historical data, optimizes the amplification factor and protection threshold through the gray wolf algorithm, and realizes intelligent self-tuning. This circuit realizes a current detection accuracy of ±0.5% FS and a response time < 200μs through the cooperation of multiple modules, and is applicable to scenarios such as industrial motor control and new energy vehicle charging. It can effectively monitor abnormal states such as overcurrent and underload, and optimize the system energy efficiency through power calculation. The constant current source differential amplifier circuit consists of the following core parts: Constant Current Source: Provides a stable tail current EEIEE to ensure the stability of the operating point of the differential pair transistors. Differential Pair: Consists of two matched transistors (BJT or MOSFET), which amplifies the difference of the input signals. Load Resistors: Located at the collector (or drain) of the differential pair transistors, converts the current change into a voltage output. Feedback Network (optional): Used to adjust the gain or introduce negative feedback to improve linearity. Differential Pair: Consists of two matched transistors (BJT or MOSFET), which amplifies the difference of the input signals. Load Resistors: Located at the collector (or drain) of the differential pair transistors, converts the current change into a voltage output. Feedback Network: Used to adjust the gain or introduce negative feedback to improve linearity.

[0034] In a further embodiment, the secondary circuit voltage drop compensation module includes amplitude compensation, phase compensation, or dynamic compensation of the secondary circuit based on the change of load current. The working method of the secondary circuit voltage drop compensation module: Select an electric energy metering instrument with a relative error not exceeding ±0.1% in electric energy metering to meet the requirements of high-precision measurement. Use an instrument with a sliding sampling method to reduce the measurement error caused by the secondary circuit voltage drop. At the same time, select amplitude compensation, phase compensation, or dynamic compensation of the secondary circuit based on the change of load current. The average response time responds to the change of the electricity quantity within three seconds, and selects the compensation method according to the load compensation type to ensure the real-time and accuracy of the metering.

[0035] The voltage drop comparison module dynamically adjusts the threshold dynamic threshold comparison according to real-time load current, voltage, ripple, magnetic field, vibration, load, or temperature parameters; The working method for real-time monitoring of voltage and current signals in the secondary circuit is as follows: The voltage and current in the secondary circuit are converted into electrical signals through sensors, the signals output by the sensors are amplified through a signal amplification circuit, and the signals are filtered and denoised through a signal conditioning circuit to improve the accuracy and stability of the signals. The processed analog signals are sent to an analog-to-digital converter to convert the analog signals into digital signals with higher anti-interference ability and transmission efficiency. The collected digital signals are temporarily stored in the memory of the data acquisition module, and the data is preprocessed to reduce the bandwidth occupied by data transmission and the storage space. Then, the collected data is encapsulated. The encapsulation content includes at least information such as adding a data header and a check code. According to the requirements of the monitoring center or cloud platform, the Modbus protocol, 485 communication protocol, or blockchain communication protocol is selected for data transmission. The data is converted into binary or hexadecimal codes in a specific format. The encapsulated and format-converted data is transmitted to the monitoring center or cloud platform in real time through a wired / wireless network. During the transmission process, the data is forwarded and routed through multiple relay nodes or routers. After receiving the data, the monitoring center or cloud platform performs data reception and confirmation operations. If the data is lost or incorrect, the system performs retransmission or alarm processing.

[0036] The working principle of the voltage drop calculation circuit module is as follows: By collecting the secondary side signals of voltage transformers and current transformers, as well as the output signals of watt-hour meters, real-time processing and analysis are carried out to monitor the voltage drop situation and the change of electrical energy in the secondary circuit. The secondary circuit electrical energy monitoring module obtains the actual operating state of the power system by collecting the secondary side voltage and current signals of voltage transformers and current transformers through the data acquisition module. The secondary circuit electrical energy monitoring module collects the output signals of watt-hour meters, at least including pulse signals or digital signals, to obtain real-time data of electrical energy. The collected voltage and current signals first pass through a signal conversion and amplification circuit to be converted into a level range for subsequent processing. Filtering technology is used for processing to ensure the accuracy of the data. The filtered signals are sent to an analog-to-digital converter to convert the analog signals into digital signals. The processed data is further processed and analyzed using Fourier transform on the digital signals to extract useful information. Based on the preprocessed data, complex numbers are used to represent current, voltage, and impedance, and calculations are performed through phasor analysis. The calculation formula for current is: In formula (1), represents voltage, and the complex representation of voltage is Z represents impedance, and the complex representation of impedance is , where R represents resistance, j represents the imaginary unit, X represents reactance, F represents the error factor affected by current. The calculation formula for voltage drop is: In formula (2), K represents the proportionality coefficient, represents the voltage drop across the resistor R. Simplify the formula using polar coordinates. In the ideal case, the formula is expressed as: In formula (3), represents the magnitude of the impedance of resistor R, represents the phase angle of the current phasor, represents the phase angle of the impedance phasor. After obtaining the voltage drop according to the formula, the magnitude and phase angle are obtained. The calculation formula for the phase difference is: In formula (4), represents the phase difference, represents the angular frequency and represents the reflection coefficient. The formula for the reflection coefficient is: In formula (5), is the characteristic impedance of the transmission line. The specific phase difference change is obtained by changing the phase of the signal according to the phase part of the reflection coefficient r. On-site, the 500 kV fault recorder screens of No. 1, No. 2, and No. 3 in a certain 500 kV substation were replaced. The old screen cabinets were removed, and new screen cabinets were installed at the original positions of the screen cabinets. The analog voltage and current, and the switch quantity cables all used the old cables. The AC power supply in the new upper screen was connected to the adjacent upper screen through the small busbar on the top of the screen. The No. 1 and No. 2 fault recorder devices replaced this time are line fault recorders, which are respectively connected to the voltages and currents of the 2 500 kV line protections. The wiring method of the voltage secondary circuit is shown in Figure 1; the No. 3 fault recorder device is a bus fault recorder, which is mainly connected to the current of the bus side switch. The secondary safety measures implemented for the replacement of the 500 kV No. 1, No. 2, and No. 3 fault recorder screens in this period mainly include the following three parts: (1) Short-circuit the four operating line current circuits in the operating cabinet to the No. 1 and No. 2 fault recorder screens; (2) Short-circuit the side switch protection to the side switch current circuit in the No. 3 fault recorder screen; (3) Disconnect the voltage terminal wiring for the No. 1 and No. 2 fault recorders in the voltage transformer terminal boxes of the four operating lines. After implementing the secondary safety measures for the transformation of the 500 kV No. 1, No. 2, and No. 3 fault recorders, the voltage sampling of the second set of protections of the 4 500 kV lines is normal, but when measuring the voltage of the N line of the protection voltage circuit to the ground with a multimeter, it is about 10 V. Investigation of the abnormal reasons Since there is a floating voltage on the N line, it is speculated that the ground wire of the N line is disconnected from the ground in the protection room. By checking the routing of the small busbars on the top of the panels in the 500 kV relay protection room, it is found that the routing of N600 on the top of the panels is from the 220 kV relay PT paralleling panel to the watt-hour meter panel in the 500 kV relay room, then from the cable trench to the top of the 500 kV first string measurement and control panel, then from the cable trench to the top of the 500 kV busbar and common measurement and control panel, then from the top of the panel to the 500 kV No. 1, 2, 3 fault recorders and the 500 kV second string measurement and control panel, and finally from the cable trench to the top of the 500 kV third string measurement and control panel.

[0037] In a specific embodiment, the received data is cleaned to remove noise and outliers, and the data is standardized to meet the requirements of subsequent analysis. The data is processed using statistical principles to calculate statistical indicators such as mean, variance, and standard deviation to understand the overall situation of power quality. Signal processing methods are applied to perform spectrum analysis, wavelet analysis, etc. on the power quality monitoring data to identify fluctuating components such as frequency, harmonics, and interruptions, and a mathematical or statistical model is established to predict and warn of power quality. A reasonable database structure is designed to store the collected electrical energy data and the processed results. The cleaned and processed data is stored in the database for subsequent query and analysis, ensuring the security and reliability of the database to prevent data loss or damage. A user-friendly interface is designed to display the real-time monitored electrical energy data and the processed results in the form of charts, curves, etc., intuitively showing the change trends and characteristics of the electrical energy data, providing a query function that allows users to query historical data as needed, setting thresholds, and triggering an alarm function when the electrical energy data exceeds the threshold to alert users of abnormal situations, and providing fault location and diagnosis information to help users quickly locate and solve problems. Assume that the data obtained after processing the secondary circuit of the current transformer during monitoring is: secondary circuit load current Total impedance of the secondary circuit , according to Ohm's law, the calculation formula for the secondary circuit voltage drop is: In formula (6), M represents the voltage generated by additional factors, usually zero. Substituting the data shows the voltage drop of the secondary circuit The voltage drop generated by the load current in the secondary circuit across the total impedance is 20V. This means that in the secondary circuit of the current transformer, the voltage drop due to the current passing through the impedance is reduced by 20V. Further, the working principle of the redundant design is as follows: by adding additional monitoring channels or sensors to monitor the voltage drop situation in the secondary circuit in real time. When a certain monitoring channel fails, other channels can still continue to work, ensuring the continuity and accuracy of the monitoring data. A system is constructed using a data acquisition module, a communication module, a control module, and a power module. When a certain hardware component fails, it automatically switches to a standby component to ensure the normal operation of the system. By writing redundant software code or algorithms to enhance the fault tolerance of the system. When a certain software module fails, other modules can still continue to execute, ensuring the stability and reliability of the system; The working principle of the fault switching mechanism is as follows: The system detects faults by monitoring the working status of each component in real time. When a certain component fails, the system immediately issues an alarm and starts the fault switching program. According to the type and severity of the fault, the system makes a switching decision. After making the switching decision, the system immediately executes the switching operation, which includes steps such as shutting down the faulty component, starting the standby component, and reconfiguring the system. The switching process must be fast and seamless to ensure the continuity and stability of the system. After the switching is completed, the system verifies and tests the new working status, including checking the accuracy of the monitoring data and the reliability of the communication. If the verification fails, the system will re - initiate the switching or take other remedial measures. In a further embodiment, the working principle of the short - circuit protection circuit is as follows: by adding additional monitoring channels or sensors to monitor the voltage drop situation in the secondary circuit in real time. When a certain monitoring channel fails, other channels can still continue to work, ensuring the continuity and accuracy of the monitoring data. A system is constructed using a data acquisition module, a communication module, a control module, and a power module. When a certain hardware component fails, it automatically switches to a standby component through a relay circuit to ensure the normal operation of the system; The working principle of the automatic switching of the relay circuit is as follows: When a certain component fails, the alarm module immediately issues an alarm and starts the fault switching program. According to the type and severity of the fault, the system makes a switching decision. Information switching is achieved by shutting down the faulty component, starting the standby component, or reconfiguring the system. If the verification fails, a new switching instruction is re - initiated. A 24 - hour uninterrupted power energy monitoring system for the voltage drop in the secondary circuit is characterized in that it applies a method for 24 - hour uninterrupted power energy monitoring of the voltage drop in the secondary circuit described in any one of the above - mentioned embodiments.

[0038] In a specific embodiment, the reliability and fault tolerance of the system are improved by adding additional devices or circuits. Two independent secondary circuits are used for voltage drop monitoring, and each circuit is equipped with complete measuring instruments and signal transmission devices. When one circuit fails, the other circuit can immediately take over the monitoring task to ensure the continuity of monitoring. Through hot standby and cold standby processing, hot standby means that the standby device runs simultaneously with the main device, but only the main device undertakes the monitoring task, and the standby device is in a standby state. Once the main device fails, the standby device can immediately switch to the working state. Cold standby means that the standby device does not run and only starts when the main device fails. Although the switching time may be slightly longer, the cost is lower. The redundant power supply design provides redundant power for the monitoring system to ensure that when the main power supply fails, the standby power supply can immediately take over the power supply task and prevent the monitoring system from being interrupted due to power failure.

[0039] The fault switching mechanism refers to the process of automatically or manually switching the monitoring task to a standby device or circuit in the secondary circuit voltage drop monitoring system. By setting up a fault detection module in the monitoring system, the operating states of the main circuit and the standby circuit are monitored in real time. Once a fault in the main circuit is detected, such as abnormal voltage drop, signal interruption, etc., the fault detection module immediately triggers a switching instruction, and the switching instruction is transmitted to the standby circuit through the control system to make it take over the monitoring task. In some cases, manual intervention may be required to perform the switching operation. For example, when the automatic switching system fails, or when maintenance needs to be carried out on the standby circuit, a manual switching switch or button can be set, and the operator can manually perform the switching operation according to the on-site situation. Whether it is automatic switching or manual switching, after the switching is completed, the standby circuit needs to be verified to ensure that it can normally undertake the monitoring task. Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that these specific implementation manners are only examples. Without departing from the principles and essence of the present invention, those skilled in the art can make various omissions, substitutions, and changes to the details of the above methods and systems. For example, combining the above method steps so as to perform substantially the same function in a substantially the same way to achieve substantially the same result belongs to the scope of the present invention. Therefore, the scope of the present invention is only defined by the appended claims.

Claims

1. A method for monitoring the voltage drop of a secondary circuit for 24 hours without interruption, characterized in that: The steps include: Step 1: Conduct an on-site survey of the monitoring location to determine the location and number of monitoring points, install current sensors with an accuracy of ±0.1% and voltage sensors with an accuracy of ±0.05%, set the frequency band of 50Hz-1kHz for measurement, and monitor the voltage and current signals in the secondary circuit in real time; realize synchronous sampling of the master and slave sensors through the GPS timing module with an accuracy of 0.5μs to ensure the time alignment of the voltage / current waveforms; Step 2: By setting the abnormal mode self-identification module to measure or detect the measured point online in real time 24 hours a day, the current zero-crossing signal is used as the synchronization source in the secondary circuit, and the full cycle synchronization of the master and slave devices is achieved through the two-way handshake protocol; the detection range is increased through the threshold dynamic adjustment module; Step 3: Real-time monitoring of the electric energy data of the power system through a secondary circuit electric energy monitoring module, wherein the secondary circuit electric energy monitoring module comprises: A blockchain module based on the SE050 security chip and an electric energy loss calculation module, a measurement loop error calculation module, a secondary loop voltage drop compensation module, and a voltage drop comparison module connected to the blockchain module; Step 4: Collect the voltage and current signals output by the monitoring point through the LoRa / NB-IoT module, and transmit the monitored data information to the monitoring center or cloud platform in real time with a transmission interval of ≤1 minute; When hardware or software fails, it automatically switches to the backup system to ensure 24-hour uninterrupted monitoring.

2. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: In the step one, the monitoring points are set at the secondary side of the voltage transformer, the input end of the electric energy meter, and both ends of the coil of the important relay to monitor the key nodes that have a large impact on the voltage drop. Monitoring points are set at different positions of the loop to ensure that the voltage drop of the entire loop can be fully reflected; the number of monitoring points is directly proportional to the complexity and length of the secondary loop, and the number of monitoring points is limited considering the cost.

3. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: In step one, the voltage sensor is installed at the output end of the secondary side of the voltage transformer or the input end of the electric energy meter, and the current sensor is installed at the output end of the secondary side of the current transformer or on a conductor directly connected to the current path in the secondary circuit. A voltage transformer secondary circuit voltage drop tester is used for direct measurement. The tester checks the correctness of the wiring, takes out the voltage drop signal after isolation, and displays the amplitude error and phase error of the secondary voltage drop.

4. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: In the step 2, the working method of the abnormal mode self-identification module is: The voltage, voltage drop value, equipment status code, current, ripple, magnetic field or vibration data information are detected through the DSP digital signal processor. The environmental data impact, historical data real-time data stream and different types of data information are set through dynamic thresholds. The sampling frequency is dynamically adjusted through the electromagnetic field strength sensor to suppress interference. The timing information error is <0.45μs. The electromagnetic coupling interference is avoided through a 1:2 isolation transformer. The time domain waveform distortion rate, spectrum entropy and time-frequency characteristics are extracted. The dynamic threshold module automatically adjusts the alarm threshold according to the ambient temperature and humidity or load changes to avoid fixed threshold false alarms. The master device triggers sampling through the current zero-crossing signal, and the entire cycle synchronization is achieved after the slave device responds and confirms. When the abnormal probability exceeds the threshold, the alarm is triggered and the abnormal waveform is recorded, and the circuit breaker operation is executed.

5. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: The electric energy loss calculation module includes a Kalman filter calculation module, a voltage drop calculation circuit module, a parallel data channel module, a constant current source differential amplifier circuit module and a waveform distortion calculation module, wherein the output end of the Kalman filter calculation module is connected to the input end of the voltage drop calculation circuit module, the output end of the voltage drop calculation circuit module is connected to the input end of the parallel data channel module, the output end of the parallel data channel module is connected to the input end of the constant current source differential amplifier circuit module, the output end of the constant current source differential amplifier circuit module is connected to the input end of the waveform distortion calculation module, wherein the voltage drop calculation circuit module includes a current detection circuit, a differential calculation circuit, a rectification control circuit and a short-circuit protection circuit, the output end of the current detection circuit is connected to the input end of the differential calculation circuit, the output end of the differential calculation circuit is connected to the input end of the rectification control circuit, and the output end of the rectification control circuit is connected to the input end of the short-circuit protection circuit.

6. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: The measurement loop error calculation module at least includes a power measurement error calculation module, a timing measurement error calculation module, a frequency measurement error calculation module or a pulse measurement error calculation module; The secondary circuit voltage drop compensation module includes amplitude compensation, phase compensation or secondary circuit dynamic compensation based on load current changes. The working method of the secondary circuit voltage drop compensation module is as follows: In electric energy metering, electric energy metering instruments with a relative error not exceeding ±0.1% are selected to meet the requirements of high-precision measurement. Instruments with sliding sampling method are used to reduce the measurement error caused by the voltage drop in the secondary circuit. At the same time, amplitude compensation, phase compensation or secondary circuit dynamic compensation based on load current changes are selected. The average response time responds to changes in electric quantity within three seconds. The compensation method is selected according to the load compensation type to ensure the real-time and accuracy of the measurement.

7. A 24-hour uninterrupted power energy monitoring method for secondary circuit voltage drop according to claim 1, characterized in that: The voltage drop comparison module dynamically adjusts the threshold value dynamic threshold comparison according to real-time load current, voltage, ripple, magnetic field, vibration, load or temperature parameters; The working method of real-time monitoring of the voltage and current signals in the secondary circuit is as follows: the voltage and current in the secondary circuit are converted into electrical signals through sensors, the signals output by the sensors are amplified through signal amplification circuits, the signals are filtered and denoised through signal conditioning circuits to improve the accuracy and stability of the signals, the processed analog signals are sent to analog-to-digital converters to convert the analog signals into digital signals with higher anti-interference capability and transmission efficiency, the collected digital signals are temporarily stored in the memory of the data acquisition module, and the data are pre-processed to reduce the bandwidth of data transmission and the occupation of storage space; The collected data is then encapsulated, and the encapsulation content at least includes the information of adding a data header and a checksum. According to the requirements of the monitoring center or cloud platform, the Modbus protocol, 485 communication protocol, or blockchain communication protocol is selected for data transmission, and the data is converted into a binary or hexadecimal code in a specific format. The encapsulated and format-converted data is transmitted to the monitoring center or cloud platform in real time via a wired / wireless network. During the transmission process, the data is forwarded and routed through multiple relay nodes or routers. After receiving the data, the monitoring center or cloud platform receives and confirms the data. If the data is lost or erroneous, the system will retransmit or alarm.

8. A method for monitoring the voltage drop of a secondary circuit for 24 hours without interruption according to claim 5, characterized in that: The working principle of the voltage drop calculation circuit module is as follows: by collecting the secondary side signals of the voltage transformer and the current transformer, and the output signal of the electric energy meter for real-time processing and analysis, the voltage drop of the secondary circuit and the change of electric energy are monitored; the secondary circuit electric energy monitoring module collects the secondary side voltage and current signals of the voltage transformer and the current transformer through the data acquisition module to obtain the actual operation state of the power system; the secondary circuit electric energy monitoring module collects the output signal of the electric energy meter, including at least a pulse signal or a digital signal, to obtain the real-time data of electric energy; the collected voltage and current signals are first converted into the level range for subsequent processing through the signal conversion and amplification circuit, and processed by filtering technology to ensure the accuracy of the data; the filtered signal is sent to the analog-to-digital converter to convert the analog signal into a digital signal; the processed data is further processed and analyzed by Fourier transform to extract useful information; According to the preprocessed data, complex numbers are used to represent current, voltage and impedance, and the calculation is performed through phasor analysis. The current calculation formula is: In formula (1), represents voltage, and the complex number of voltage is represented by Z represents impedance, and the complex impedance is expressed as , where R represents resistance, j represents imaginary unit, X represents reactance, and F represents the error factor affected by current. The voltage drop is calculated as: In formula (2), K represents the proportionality coefficient, Represents the voltage drop on the resistor R. The formula is simplified using polar coordinates. The ideal formula is: In formula (3), represents the magnitude of the impedance of the resistor R, represents the phase angle of the current phasor, Represents the phase angle of the impedance phasor. The voltage drop is obtained according to the formula to obtain the amplitude and phase angle. The calculation formula for the phase difference is: In formula (4), represents the phase difference, represents the angular frequency and Represents the reflection coefficient. The formula for the reflection coefficient is: In formula (5), It is the characteristic impedance of the transmission line. The specific phase difference change is obtained by changing the phase change of the signal according to the phase part of the reflection coefficient r.

9. A method for monitoring the voltage drop of a secondary circuit for 24 hours without interruption according to claim 5, characterized in that: The working principle of the short-circuit protection circuit is as follows: by adding additional monitoring channels or sensors to monitor the voltage drop of the secondary circuit in real time, when a monitoring channel fails, other channels can continue to work to ensure the continuity and accuracy of the monitoring data, and the system is constructed by using a data acquisition module, a communication module, a control module and a power module. When a hardware component fails, it automatically switches to a backup component through a relay circuit to ensure the normal operation of the system; The working principle of automatic switching of relay circuit is: When a component fails, the alarm module immediately sounds an alarm and starts the fault switching procedure. Based on the type and severity of the fault, the system makes a switching decision and implements information switching by shutting down the failed component, starting the backup component, or reconfiguring the system. If the verification fails, the switching command is re-initiated.

10. A 24-hour uninterrupted power energy monitoring system for secondary circuit voltage drop, characterized in that: A 24-hour uninterrupted power energy monitoring method for a secondary circuit voltage drop as described in any one of claims 1 to 9.

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