Power distribution automation terminal working module voltage measurer and measuring method

Abstract

The invention relates to the technical field of power distribution automation terminal equipment operation and maintenance, and discloses a power distribution automation terminal working module voltage measurer which comprises a measurer shell, a plurality of input ports installed on the measurer shell, and a signal conditioning circuit located in the measurer shell and electrically connected with the input ports. The analog-to-digital converter is electrically connected with the signal conditioning circuit, the digital processing unit is electrically connected with the analog-to-digital converter, and the display module, the data storage module and the communication interface are electrically connected with the digital processing unit. And the power supply module is positioned in the measurer shell and is electrically connected with the signal conditioning circuit, the analog-to-digital converter, the digital processing unit and the data storage module. Through the display screen of the power distribution automation terminal working module voltage measurer, the voltage conditions of an internal working power supply, a back-up power supply, a device power supply and a communication power supply of power distribution automation terminal equipment are displayed in real time, so that an operator can intuitively judge a fault point.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution automation terminal equipment operation and maintenance, and in particular to a distribution automation terminal working module voltage measuring device and a measuring method. Background Art

[0002] In the daily operation and maintenance of distribution automation terminal equipment, it is very important to ensure the normal operation of the power module. Especially when a fault occurs, the operation and maintenance personnel need to accurately determine the problem, and the power modules involved mainly include:

[0003] Internal working power supply: provides the power required for basic functions of the device;

[0004] Backup power: Maintain critical equipment functions when the main power source fails;

[0005] Device power supply: usually used for control and monitoring of the entire system;

[0006] Communication power supply: ensure stable communication between the equipment and external systems.

[0007] Challenges in fault diagnosis: In actual operation, due to the lack of experience of new employees in distribution automation terminal equipment, when a device fails, they often need to measure the voltage of the four power modules one by one. This process usually includes the following steps:

[0008] On-site preparation: The operation and maintenance personnel first need to prepare the corresponding measurement tools, such as a multimeter;

[0009] Shutdown procedures: If safety measurements are required, it may be necessary to shut down the equipment as required;

[0010] Measurement process: Due to inconvenient standing position, operation and maintenance personnel may need to climb on the tower and build temporary structures to conduct voltage measurements.

[0011] In the daily operation and maintenance of distribution automation terminal equipment, the following problems exist:

[0012] The fault judgment of the distribution automation terminal is inaccurate:

[0013] For maintenance personnel who are not familiar with the equipment, manually measuring the voltage of power modules one by one may lead to misjudgment. Voltage fluctuations in some modules may not directly mean a fault, but may be caused by external factors or instantaneous changes, which can easily lead to unnecessary maintenance.

[0014] Low work efficiency:

[0015] In high-altitude working environments such as poles and towers, the safety risks of equipment inspection and power supply measurement are high, and due to the limited working space, operation and maintenance personnel need to spend more time to complete the measurement. For example, when working on a pole tower, personnel may need to move up and down repeatedly to find a suitable measurement point, which greatly increases working time and labor intensity.

[0016] Security risks:

[0017] Working at heights is inherently risky. Long hours of measurement work may cause a decrease in concentration and increase the probability of accidents. In addition, changes in the external environment (such as weather, wind speed, etc.) may also affect work safety.

[0018] Lack of automation:

[0019] Traditional manual measurement methods are inefficient and difficult to achieve real-time monitoring. Once a fault occurs, there is a lack of fast diagnostic tools, and maintenance personnel often need to spend a lot of time to troubleshoot.

[0020] In summary, in the daily operation and maintenance of distribution automation terminal equipment, there is an urgent need for a distribution automation terminal working module voltage measuring device that can improve work efficiency and reduce the labor intensity of operators. Summary of the invention

[0021] To solve the above problems, the present invention provides a distribution automation terminal working module voltage measuring device and measurement method, which is easy to use, can improve the voltage measurement efficiency of the distribution automation terminal working module, and greatly reduce the labor intensity of operators.

[0022] The technical solution adopted by the present invention is:

[0023] A voltage meter for a power distribution automation terminal working module comprises a meter housing, a plurality of input ports mounted on the meter housing, a signal conditioning circuit located in the meter housing and electrically connected to the input ports, an analog-to-digital converter located in the meter housing and electrically connected to the signal conditioning circuit, a digital processing unit located in the meter housing and electrically connected to the analog-to-digital converter, a display module, a data storage module and a communication interface located in the meter housing and electrically connected to the digital processing unit, and a power module located in the meter housing and electrically connected to the signal conditioning circuit, the analog-to-digital converter, the digital processing unit and the data storage module.

[0024] Furthermore, the input port is capable of processing single-phase or three-phase voltage input, it can insert a measurement connection line, and is connected to the power module of the distribution automation terminal equipment through the measurement connection line to receive the voltage signal from the power module; the input port is connected to the signal conditioning circuit through the connection line.

[0025] Further, the signal conditioning circuit includes an isolation transformer, an attenuator and a filter;

[0026] The isolation transformer is connected between the input port and the attenuator to provide electrical isolation;

[0027] The attenuator is connected after the isolation transformer to attenuate the higher voltage signal so that the voltage signal is within the appropriate range to meet the input requirements of the analog-to-digital converter;

[0028] The filter is connected after the attenuator to eliminate high frequency noise.

[0029] Furthermore, the analog-to-digital converter converts the analog voltage signal output by the signal conditioning circuit into a digital signal; and the output end of the analog-to-digital converter is connected to the digital processing unit.

[0030] Furthermore, the digital processing unit includes a microprocessor or a digital signal processor that analyzes the digital signal output by the analog-to-digital converter; the digital processing unit calculates the effective value, maximum value, minimum value and fluctuation of the voltage based on the digital signal output by the analog-to-digital converter; and the output end of the digital processing unit is connected to the storage module and the communication interface.

[0031] Furthermore, a display screen, namely a button, is installed on the housing of the measuring device, and the display screen is connected to the output end of the digital processing unit.

[0032] A method for measuring the voltage of a distribution automation terminal working module is provided. The method is based on the above-mentioned distribution automation terminal working module voltage measuring device and comprises the following steps:

[0033] Step 1, voltage signal acquisition: insert a measurement connection line through the multi-channel voltage input port, and connect it to the power module of the distribution automation terminal equipment through the measurement connection line to collect the AC voltage signals of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment;

[0034] Step 2, signal conditioning: The input voltage signal is electrically isolated through the isolation transformer of the signal conditioning circuit in turn to ensure the safety of the measurement; it is attenuated by the attenuator of the signal conditioning circuit to adapt to the input range of the analog-to-digital converter; finally, the high-frequency noise is eliminated by the filter of the signal conditioning circuit to ensure the measurement accuracy;

[0035] Step 3, analog-to-digital conversion: the analog voltage signal conditioned by the signal conditioning circuit is sampled by an analog-to-digital converter and converted into a digital signal;

[0036] Step 4, data processing: The digital signal is analyzed by the digital processing unit to calculate the effective value RMS, maximum value, minimum value and fluctuation range of the voltage;

[0037] Step 5, data storage, communication and display: The digital processing unit outputs the effective value RMS, maximum value, minimum value and fluctuation range of the voltage to the data storage module for storage, to the display screen for display, and to other devices connected to the communication interface.

[0038] Furthermore, the digital processing unit calculates the voltage effective value RMS by the following formula:

[0039]

[0040] Among them, V RMS is the voltage RMS; N is the total number of sampling points; i is the i-th sampling point; V i is the instantaneous voltage value sampled;

[0041] The digital processing unit calculates the voltage fluctuation range by the following formula:

[0042] ΔV=V max -V min

[0043] Among them, ΔV is the voltage fluctuation range; V max is the maximum voltage value in the collected data; V min is the minimum voltage value in the collected data.

[0044] Furthermore, a comparator module electrically connected to the analog-to-digital converter, the power module and the display screen is also provided in the housing of the measuring device. The comparator can compare the internal working power supply, the backup power supply, the device power supply and the communication power supply in pairs to obtain the maximum voltage value, the minimum voltage value and the relative difference;

[0045] The comparison process includes the following steps:

[0046] Step 1, each voltage signal is conditioned by a signal conditioning circuit and processed by an analog-to-digital converter to obtain digitized voltage values ​​V1, V2, V3 and V4, where V1, V2, V3 and V4 represent the voltage measurement values ​​from the internal working power supply, backup power supply, device power supply and communication power supply input to the input port respectively;

[0047] Step 2, using a comparator to compare the voltages of each group in pairs, and obtain the maximum voltage value, the minimum voltage value and the relative difference;

[0048] The maximum voltage value is calculated according to the following formula:

[0049] V max =max(V1,V2,V3,V4)

[0050] V maxis the maximum value of the four groups of voltage signals;

[0051] The minimum voltage value is calculated according to the following formula:

[0052] V min =min(V1,V2,V3,V4)

[0053] V min is the minimum value of the four groups of voltage signals;

[0054] The relative deviation is calculated by the following formula:

[0055]

[0056] Where, ΔV ij is the voltage V i and V j The relative deviation percentage between i and V j Indicates the voltage value of the two groups of comparison; V avg is the average value of the four groups of voltages, and the calculation formula is:

[0057]

[0058] The voltage difference is calculated by the following formula:

[0059] ΔV=V max -V min

[0060] Among them, ΔV is the difference between the maximum and minimum values ​​of the four groups of voltage signals;

[0061] Step 3: The comparator displays the calculation results of the maximum value, minimum value, relative deviation and voltage difference to the operation and maintenance personnel in real time through the display screen; if the relative deviation of a group of voltages from other voltages exceeds the set threshold, an alarm signal is triggered, indicating that the group of voltages may be abnormal.

[0062] Further, in step 2, during the signal conditioning process;

[0063] If the filter is implemented by hardware circuit or software to filter the input signal in real time, the filter adopts a low-pass filter, the order of which is first-order or second-order, and the response type of the filter is Butterworth filter or Chebyshev filter;

[0064] The cutoff frequency of the low-pass filter is f c , that is, the highest frequency allowed for the signal to pass through, and the signal exceeding this frequency will be gradually attenuated; the selection of the cutoff frequency is usually based on the signal band. If the sampled power is 50Hz industrial frequency AC, a cutoff frequency of about 100Hz is selected to remove noise signals above 100Hz;

[0065]

[0066] Among them, R is the resistance constituting the low-pass filter, and C is the capacitance constituting the low-pass filter;

[0067] The filter has a built-in transfer function H (s) , when using a first-order low-pass filter, When using a second-order low-pass filter,

[0068] Among them, R is the resistance of the low-pass filter, and C is the capacitance of the low-pass filter; ω c is the cut-off angular frequency, ω c =2πf c ; s is a complex frequency variable;

[0069] If the filtering process is performed in the digital signal processing unit, the filter uses a differential equation to implement digital filtering, and the calculation formula is as follows:

[0070] y[n]=a1x[n]+a2x[n-1]+...+b1y[n-1]+b2y[n-2]+...

[0071] Among them, y[n] is the nth sampling point of the output signal; x[n] is the nth sampling point of the input signal; a1, a2, ... are the input coefficients of the filter; b1, b2, ... are the feedback coefficients of the filter.

[0072] The beneficial effects of the present invention are:

[0073] 1. Real-time monitoring and fault diagnosis:

[0074] The display screen of the voltage measuring device of the distribution automation terminal working module can display the voltage conditions of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment in real time, so that the operator can intuitively determine the fault point.

[0075] 2.Multi-channel input and efficient measurement:

[0076] The distribution automation terminal working module voltage meter can simultaneously measure the four-way AC voltage of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment, greatly improving work efficiency and reducing the time for operation and maintenance personnel to measure one by one on site.

[0077] 3. Improve safety and reduce labor intensity:

[0078] The signal conditioning circuit of the voltage measuring device of the distribution automation terminal working module is equipped with an isolation transformer to ensure safe operation; the overall compact design of the voltage measuring device of the distribution automation terminal working module makes the device light and easy to use, reducing the burden on high-altitude workers.

[0079] The voltage meter of the distribution automation terminal working module can help operation and maintenance personnel quickly and accurately measure the voltage and diagnose faults of distribution automation terminal equipment, and is suitable for daily operation and maintenance and fault detection work scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0081] Figure 1 This is a structural diagram of a voltage measuring device for a power distribution automation terminal working module of the present invention;

[0082] Figure 2 and Figure 3 This is a diagram showing the internal connection relationship of the voltage measuring device of the power distribution automation terminal working module of the present invention.

[0083] Figure 4 It is a flow chart of the voltage measurement method of the distribution automation terminal working module of the present invention;

[0084] In the figure, 1. measuring instrument housing; 2. input port; 3. display screen; 4. buttons. DETAILED DESCRIPTION

[0085] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0086] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other without conflict. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0087] Example 1

[0088] In view of the daily operation and maintenance of distribution automation terminal equipment, it is necessary to measure the voltage of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment, which has low work efficiency and high labor intensity. This embodiment provides a distribution automation terminal working module voltage meter.

[0089] like Figure 1 As shown, the distribution automation terminal working module voltage meter includes a meter housing 1, and four input ports 2 installed on the meter housing 1; Figure 2 As shown, the distribution automation terminal working module voltage meter also includes a signal conditioning circuit located in the measuring device housing 1 and electrically connected to the input port 2, an analog-to-digital converter located in the measuring device housing 1 and electrically connected to the signal conditioning circuit, a digital processing unit located in the measuring device housing 1 and electrically connected to the analog-to-digital converter, a display module, a data storage module and a communication interface located in the measuring device housing 1 and electrically connected to the digital processing unit, and a power supply module located in the measuring device housing 1 and electrically connected to the signal conditioning circuit, the analog-to-digital converter, the digital processing unit and the data storage module.

[0090] like Figure 2 As shown, input port 2 is capable of processing single-phase or three-phase voltage input, input port 2 can be inserted with a measurement connection line, and connected to a power module of a distribution automation terminal device through the measurement connection line, thereby receiving a voltage signal from the power module; input port 2 is connected to a signal conditioning circuit through a connection line.

[0091] The signal conditioning circuit includes an isolation transformer, an attenuator, and a filter. The isolation transformer is connected between input port 2 and the attenuator to provide electrical isolation and ensure the safety of the measurement equipment. The attenuator is connected after the isolation transformer to attenuate the higher voltage signal so that the voltage signal is within an appropriate range to meet the input requirements of the analog-to-digital converter. The filter is connected after the attenuator to eliminate high-frequency noise.

[0092] The analog-to-digital converter converts the analog voltage signal output by the signal conditioning circuit into a digital signal; the output end of the analog-to-digital converter is connected to the digital processing unit.

[0093] The digital processing unit includes a microprocessor or a digital signal processor that analyzes the digital signal output by the analog-to-digital converter; the digital processing unit calculates the effective value, maximum value, minimum value and fluctuation of the voltage based on the digital signal output by the analog-to-digital converter; the output end of the digital processing unit is connected to the storage module and the communication interface. The storage module is used to store the measured voltage data and timestamp, and the storage module can use an SD card or an internal memory. The communication interface provides communication protocols such as MODBUS and TCP / IP for uploading the measured data to a monitoring system or other equipment, and the communication interface is connected to the output end of the digital processing unit.

[0094] The power module includes a working power supply, a backup power supply, a device power supply and a communication power supply, and is used to provide a continuous and stable power supply for the entire device. The power module is connected to the power input terminal of the entire device. Furthermore, a display screen 3, i.e., a button 4, is also installed on the housing 1 of the measuring device, and the display screen 3 is connected to the output terminal of the digital processing unit.

[0095] The voltage measuring device of the distribution automation terminal working module can measure the voltage of four power modules at the same time, reducing the time for operation and maintenance personnel to measure one by one and improving the overall work efficiency. The device is equipped with an intuitive display screen 3, which displays the voltage value of each power module in real time, allowing operation and maintenance personnel to quickly locate the fault point without complicated operation steps. The use of isolation transformers to provide electrical isolation enhances the safety of measurement and avoids the potential danger of high voltage to operation and maintenance personnel. The voltage signal is attenuated and filtered by the signal conditioning circuit to ensure that the voltage signal input to the analog-to-digital converter is within the appropriate range, thereby improving the accuracy and stability of the measurement. The built-in data storage module can save historical measurement data and timestamps for subsequent data analysis and fault tracing. The communication interface supports multiple protocols such as MODBUS and TCP / IP, which facilitates uploading measurement data to the monitoring system and supports remote monitoring and management. Through integrated design and convenient operation, the physical labor required for operation and maintenance personnel to measure on the pole tower is reduced, and the labor intensity is reduced. The device supports single-phase and three-phase voltage input, adapts to different types of distribution automation terminal equipment, and increases its application range and flexibility.

[0096] In summary, the distribution automation terminal working module voltage meter has comprehensively improved the operation and maintenance efficiency of distribution automation terminal equipment by improving measurement efficiency, enhancing safety, improving measurement accuracy, and facilitating data management.

[0097] Example 2

[0098] Based on the distribution automation terminal working module voltage measuring device provided in the embodiment, this embodiment provides a distribution automation terminal working module voltage measuring method, such as Figure 4As shown, the voltage measurement method of the distribution automation terminal working module includes the following steps:

[0099] Step 1, voltage signal acquisition: insert a measurement connection line through the multi-channel voltage input port 2, and connect it to the power module of the distribution automation terminal equipment through the measurement connection line to collect the AC voltage signals of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment;

[0100] Step 2, signal conditioning: The input voltage signal is electrically isolated through the isolation transformer of the signal conditioning circuit in turn to ensure the safety of the measurement; it is attenuated by the attenuator of the signal conditioning circuit to adapt to the input range of the analog-to-digital converter; finally, the high-frequency noise is eliminated by the filter of the signal conditioning circuit to ensure the measurement accuracy;

[0101] Step 3, analog-to-digital conversion: the analog voltage signal conditioned by the signal conditioning circuit is sampled by an analog-to-digital converter and converted into a digital signal;

[0102] Step 4, data processing: The digital signal is analyzed by the digital processing unit to calculate the effective value RMS, maximum value, minimum value and fluctuation range of the voltage;

[0103] Step 5, data storage, communication and display: The digital processing unit outputs the effective value RMS, maximum value, minimum value and fluctuation range of the voltage to the data storage module for storage, outputs to the display screen 3 for display, and outputs to other devices connected to the communication interface.

[0104] The digital processing unit calculates the voltage effective value RMS by the following formula:

[0105]

[0106] Among them, V RMS is the voltage RMS; N is the total number of sampling points; i is the i-th sampling point; V i is the instantaneous voltage value sampled;

[0107] The digital processing unit calculates the voltage fluctuation range by the following formula:

[0108] ΔV=V max -V min

[0109] Among them, ΔV is the voltage fluctuation range; V max is the maximum voltage value in the collected data; V min is the minimum voltage value in the collected data.

[0110] The voltage measurement method of the distribution automation terminal working module isolates the voltage signal through the isolation transformer in the signal conditioning circuit, effectively preventing the potential threat of high voltage to equipment and personnel, and enhancing the safety of the system. The use of the attenuator and filter of the signal conditioning circuit can effectively eliminate external electromagnetic interference and high-frequency noise, ensure that the collected voltage signal is more accurate, and thus improve the measurement accuracy. This method can not only measure the effective value RMS, but also calculate the maximum value, minimum value and fluctuation range, provide a more comprehensive power quality analysis, and facilitate subsequent data analysis and fault detection. The digital processing unit can process and store the measured data in real time, so that the system can monitor voltage changes at any time and provide archived data for subsequent data analysis. Through the communication interface, it is convenient to connect with other devices, so as to output the measurement results to other systems, realize the interconnection between devices, and improve the compatibility and scalability of the system. The real-time display function of the measured data can quickly understand the working status of the distribution system, and improve the convenience and intuitiveness of operation. Using digital signal processing technology, the mathematical calculation formula provided can quickly process and analyze the collected voltage data, reduce the error of human calculation, and improve work efficiency. By accurately monitoring and analyzing voltage values, potential electrical faults can be discovered early, equipment damage and maintenance costs can be reduced, and the reliability of the power supply system can be improved.

[0111] In summary, the voltage measurement method of the distribution automation terminal working module has good effects in terms of safety, accuracy, real-time monitoring, data management, etc., and can effectively improve the management and maintenance efficiency of the distribution system.

[0112] Example 3

[0113] On the basis of Example 2, Figure 3 As shown, in this embodiment, a comparator module electrically connected to the analog-to-digital converter, the power module and the display screen 3 is also provided in the measuring device housing 1; the internal working power supply, the backup power supply, the device power supply and the communication power supply can be compared in pairs through the comparator to obtain the maximum voltage value, the minimum voltage value and the relative difference.

[0114] Specifically, the comparison process includes the following steps:

[0115] Step 1, each voltage signal is conditioned by a signal conditioning circuit and processed by an analog-to-digital converter to obtain digitized voltage values ​​V1, V2, V3 and V4, where V1, V2, V3 and V4 represent the voltage measurement values ​​from the internal working power supply, backup power supply, device power supply and communication power supply input to input port 2 respectively;

[0116] Step 2, using a comparator to compare the voltages of each group in pairs, and obtain the maximum voltage value, the minimum voltage value and the relative difference;

[0117] The maximum voltage value is calculated according to the following formula:

[0118] V max =max(V1,V2,V3,V4)

[0119] V max is the maximum value of the four groups of voltage signals;

[0120] The minimum voltage value is calculated according to the following formula:

[0121] V min =min(V1,V2,V3,V4)

[0122] V min is the minimum value of the four groups of voltage signals;

[0123] The relative deviation is calculated by the following formula:

[0124]

[0125] Where, ΔV ij is the voltage V i and V j The relative deviation percentage between i and V j Indicates the voltage value of the two groups of comparison; V avg is the average value of the four groups of voltages, and the calculation formula is:

[0126]

[0127] The voltage difference is calculated by the following formula:

[0128] ΔV=V max -V min

[0129] Among them, ΔV is the difference between the maximum and minimum values ​​of the four groups of voltage signals;

[0130] In step 3, the comparator displays the calculation results of the maximum value, minimum value, relative deviation and voltage difference to the operation and maintenance personnel in real time through the display screen 3; if the relative deviation between a certain group of voltages and other voltages exceeds the set threshold, an alarm signal is triggered, indicating that the group of voltages may be abnormal.

[0131] By comparing the voltage values ​​of the internal working power supply, backup power supply, device power supply and communication power supply in pairs, the maximum and minimum values ​​of the voltage can be accurately identified to ensure the accuracy of real-time monitoring. The comparator can automatically calculate the relative deviation of each group of voltage values. After setting the threshold, it can quickly identify the voltage signal with significant differences from other voltage values. This feature helps to detect power failures or abnormal conditions in a timely manner, thereby ensuring the safety and stability of the power distribution equipment. The more complex voltage comparison and calculation process is displayed in real time on the display screen 3, so that the operation and maintenance personnel can quickly understand the operating status of the system and reduce the possibility of misjudgment. Due to the automated monitoring and alarm functions, the operation and maintenance personnel can locate potential problems more efficiently, reduce the time and effort required for manual monitoring, and improve the efficiency of overall operation and maintenance management. By providing the maximum, minimum and relative differences of the voltage, the operation and maintenance personnel can make more scientific decisions based on these data, formulate reasonable maintenance and repair plans, and reduce the failure rate. The introduction of the comparator improves the monitoring mechanism of each power supply voltage, thereby enhancing the overall reliability of the distribution automation system and ensuring the long-term stable operation of the equipment.

[0132] In summary, the introduction of the comparator module not only enhances the intelligence of voltage measurement, but also improves the overall performance of the distribution automation terminal.

[0133] Example 4

[0134] Based on Example 2, in the signal conditioning process of step 2, the specific selection and filtering process of the filter are as follows:

[0135] Method 1:

[0136] If the filter is implemented by hardware circuit or software to filter the input signal in real time, the filter uses a low-pass filter, such as a low-pass filter LPF, to eliminate high-frequency noise and retain the signal within the required frequency range. According to the measurement requirements, the order of the filter is determined, which can be first-order or second-order, and the response type of the filter, such as Butterworth filter, Chebyshev filter, etc.

[0137] The cutoff frequency of the low-pass filter is f c , that is, the highest frequency allowed for the signal to pass through, and the signal exceeding this frequency will be gradually attenuated; the selection of the cutoff frequency is usually based on the signal band. If the sampled power is 50Hz industrial frequency AC, a cutoff frequency of about 100Hz is selected to remove noise signals above 100Hz;

[0138]

[0139] Among them, R is the resistance constituting the low-pass filter, and C is the capacitance constituting the low-pass filter.

[0140] The filter has a built-in transfer function H (s) , when using a first-order low-pass filter, When using a second-order low-pass filter,

[0141] Among them, R is the resistance of the low-pass filter, and C is the capacitance of the low-pass filter; ω c is the cut-off angular frequency, ω c =2πf c ; s is a complex frequency variable.

[0142] The filter is implemented through hardware circuit or software to filter the input signal in real time; the high-frequency components of the filtered signal are suppressed, and only the signal within the required frequency range is retained.

[0143] Method 2:

[0144] If the filtering process is performed in the digital signal processing unit, the filter uses a differential equation to implement digital filtering, and the calculation formula is as follows:

[0145] y[n]=a1x[n]+a2x[n-1]+...+b1y[n-1]+b2y[n-2]+...

[0146] Among them, y[n] is the nth sampling point of the output signal; x[n] is the nth sampling point of the input signal; a1, a2, ... are the input coefficients of the filter; b1, b2, ... are the feedback coefficients of the filter.

[0147] Digital filters such as llR (Infinite lmpulse Response) and FlR (Finite lmpulse Response) filters can be used.

[0148] By using a low-pass filter, high-frequency noise can be effectively suppressed and signal components related to power frequencies such as 50Hz can be retained, thereby significantly improving the signal-to-noise ratio (SNR) of the measured signal. This is crucial for accurately monitoring and analyzing voltage signals. Selecting the appropriate filter order such as first-order or second-order and response type such as Butterworth or Chebyshev can optimize the filtering effect and further improve measurement accuracy. The Butterworth filter is suitable for strict frequency domain filtering of signals with its smooth passband characteristics, while the Chebyshev filter can provide a faster roll-off, which is particularly effective for applications that require fast response. By adjusting the cutoff frequency f c , which can not only adapt to different signal characteristics and environmental noise conditions, but also be optimized according to specific application requirements. This flexibility ensures that the filter can be used in a variety of measurement scenarios.

[0149] Digital filtering implemented by differential equations in digital signal processing units, such as IIR and FIR filters, enables real-time signal processing. Compared with traditional analog filtering, digital filtering is more programmable and adaptable, and can quickly adjust and optimize algorithms to meet the needs of different industries. These two digital filters have their own advantages and disadvantages in implementation. FIR filters have precise linear phase characteristics and are suitable for applications that require phase consistency; while IIR filters usually require less computational effort when implemented and are suitable for resource-constrained embedded systems. This choice not only affects the real-time filtering effect, but also has an important impact on the utilization of system resources. The optimized filtering algorithm can reduce the fluctuation of the system when processing dynamically changing signals, so that the voltage measurement system shows higher stability and reliability when facing interference from various electrical environments.

[0150] In general, the above selection and implementation of appropriate filters can not only significantly improve the accuracy of voltage measurement and signal quality, but also enhance the flexibility, real-time and stability of the system. This is of great significance for the performance improvement and reliable operation of distribution automation terminals.

[0151] At the same time, it should be pointed out that the above description is only a typical embodiment of the present invention and does not limit the present invention in any form. Any changes made to the above embodiments based on the ideas and technical essence of the present invention are within the protection scope of the present invention.

Claims

1. A voltage measuring device for a power distribution automation terminal working module, characterized in that: The invention comprises a measuring device housing, a plurality of input ports installed on the measuring device housing, a signal conditioning circuit located in the measuring device housing and electrically connected to the input ports, an analog-to-digital converter located in the measuring device housing and electrically connected to the signal conditioning circuit, a digital processing unit located in the measuring device housing and electrically connected to the analog-to-digital converter, a display module, a data storage module and a communication interface located in the measuring device housing and electrically connected to the digital processing unit, and a power supply module located in the measuring device housing and electrically connected to the signal conditioning circuit, the analog-to-digital converter, the digital processing unit and the data storage module.

2. The voltage measuring device for the power distribution automation terminal working module according to claim 1 is characterized in that: The input port is capable of processing single-phase or three-phase voltage input, it can be inserted with a measurement connection line, and connected to the power module of the distribution automation terminal equipment through the measurement connection line to receive the voltage signal from the power module; the input port is connected to the signal conditioning circuit through the connection line.

3. The voltage measuring device for the power distribution automation terminal working module according to claim 1 is characterized in that: The signal conditioning circuit includes an isolation transformer, an attenuator and a filter; The isolation transformer is connected between the input port and the attenuator to provide electrical isolation; The attenuator is connected after the isolation transformer to attenuate the higher voltage signal so that the voltage signal is within the appropriate range to meet the input requirements of the analog-to-digital converter; The filter is connected after the attenuator to eliminate high frequency noise.

4. The voltage measuring device for the power distribution automation terminal working module according to claim 1 is characterized in that: The analog-to-digital converter converts the analog voltage signal output by the signal conditioning circuit into a digital signal; the output end of the analog-to-digital converter is connected to the digital processing unit.

5. The voltage measuring device for the power distribution automation terminal working module according to claim 1 is characterized in that: The digital processing unit includes a microprocessor or a digital signal processor that analyzes the digital signal output by the analog-to-digital converter; the digital processing unit calculates the effective value, maximum value, minimum value and fluctuation of the voltage based on the digital signal output by the analog-to-digital converter; the output end of the digital processing unit is connected to the storage module and the communication interface.

6. The voltage measuring device for the power distribution automation terminal working module according to claim 5, characterized in that: A display screen, namely a button, is also installed on the housing of the measuring device, and the display screen is connected to the output end of the digital processing unit.

7. A method for measuring voltage of a distribution automation terminal working module, the method for measuring voltage of a distribution automation terminal working module is based on the distribution automation terminal working module voltage measuring device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, voltage signal acquisition: insert a measurement connection line through the multi-channel voltage input port, and connect it to the power module of the distribution automation terminal equipment through the measurement connection line to collect the AC voltage signals of the internal working power supply, backup power supply, device power supply and communication power supply of the distribution automation terminal equipment; Step 2, signal conditioning: The input voltage signal is electrically isolated through the isolation transformer of the signal conditioning circuit in turn to ensure the safety of the measurement; it is attenuated by the attenuator of the signal conditioning circuit to adapt to the input range of the analog-to-digital converter; finally, the high-frequency noise is eliminated by the filter of the signal conditioning circuit to ensure the measurement accuracy; Step 3, analog-to-digital conversion: the analog voltage signal conditioned by the signal conditioning circuit is sampled by an analog-to-digital converter and converted into a digital signal; Step 4, data processing: The digital signal is analyzed by the digital processing unit to calculate the effective value RMS, maximum value, minimum value and fluctuation range of the voltage; Step 5, data storage, communication and display: The digital processing unit outputs the effective value RMS, maximum value, minimum value and fluctuation range of the voltage to the data storage module for storage, to the display screen for display, and to other devices connected to the communication interface.

8. The method for measuring voltage of a distribution automation terminal working module according to claim 7, characterized in that: The digital processing unit calculates the voltage effective value RMS by the following formula: Among them, V RMS is the voltage RMS; N is the total number of sampling points; i is the i-th sampling point; V i is the instantaneous voltage value sampled; The digital processing unit calculates the voltage fluctuation range by the following formula: ΔV=V max -V min Where ΔV is the voltage fluctuation range; V max is the maximum voltage value in the collected data; V min is the minimum voltage value in the collected data.

9. The method for measuring voltage of a distribution automation terminal working module according to claim 7, characterized in that: The housing of the measuring device is also provided with a comparator module electrically connected to the analog-to-digital converter, the power module and the display screen. The comparator can compare the internal working power supply, the backup power supply, the device power supply and the communication power supply in pairs to obtain the maximum voltage value, the minimum voltage value and the relative difference; The comparison process includes the following steps: Step 1, each voltage signal is conditioned by a signal conditioning circuit and processed by an analog-to-digital converter to obtain digitized voltage values ​​V1, V2, V3 and V4, where V1, V2, V3 and V4 represent the voltage measurement values ​​from the internal working power supply, backup power supply, device power supply and communication power supply input to the input port respectively; Step 2, using a comparator to compare the voltages of each group in pairs, and obtain the maximum voltage value, the minimum voltage value and the relative difference; The maximum voltage value is calculated according to the following formula: V max =max(V1,V2,V3,V4) V max is the maximum value of the four groups of voltage signals; The minimum voltage value is calculated according to the following formula: V min =min(V1,V2,V3,V4) V min is the minimum value of the four groups of voltage signals; The relative deviation is calculated by the following formula: Where, ΔV ij is the voltage V i and V j The relative deviation percentage between i and V j Indicates the voltage value of the two groups of comparison; V avg is the average value of the four groups of voltages, and the calculation formula is: The voltage difference is calculated by the following formula: ΔV=V max -V min Among them, ΔV is the difference between the maximum and minimum values ​​of the four groups of voltage signals; Step 3: The comparator displays the calculation results of the maximum value, minimum value, relative deviation and voltage difference to the operation and maintenance personnel in real time through the display screen; if the relative deviation of a group of voltages from other voltages exceeds the set threshold, an alarm signal is triggered, indicating that the group of voltages may be abnormal.

10. The method for measuring voltage of a distribution automation terminal working module according to claim 7, characterized in that: Step 2: During signal conditioning; If the filter is implemented by hardware circuit or software to filter the input signal in real time, the filter adopts a low-pass filter, the order of which is first-order or second-order, and the response type of the filter is Butterworth filter or Chebyshev filter; The cutoff frequency of the low-pass filter is f c , that is, the highest frequency allowed for the signal to pass through, and the signal exceeding this frequency will be gradually attenuated; the selection of the cutoff frequency is usually based on the signal band. If the sampled power is 50Hz industrial frequency AC, a cutoff frequency of about 100Hz is selected to remove noise signals above 100Hz; Among them, R is the resistance constituting the low-pass filter, and C is the capacitance constituting the low-pass filter; The filter has a built-in transfer function H (s) , when using a first-order low-pass filter, When using a second-order low-pass filter, Among them, R is the resistance of the low-pass filter, and C is the capacitance of the low-pass filter; ω c is the cut-off angular frequency, ω c =2πf c ; s is a complex frequency variable; If the filtering process is performed in the digital signal processing unit, the filter uses a differential equation to implement digital filtering, and the calculation formula is as follows: y[n]=a1x[n]+a2x[n-1]+...+b1y[n-1]+b2y[n-2]+... Among them, y[n] is the nth sampling point of the output signal; x[n] is the nth sampling point of the input signal; a1, a2, ... are the input coefficients of the filter; b1, b2, ... are the feedback coefficients of the filter.

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