Electric energy meter and metering terminal clock field detection method and system

Abstract

The invention discloses an electric energy meter and metering terminal clock on-site detection method and system, and relates to the technical field of timing and synchronization, and the method comprises the steps: constructing a clock calibrator GPS-7A system, and intercepting a high-voltage signal for overload protection during data collection; an optocoupler on-off signal output by the electric energy meter is converted into a recognizable electric signal, and GPSamp is used; the Beidou receiver obtains standard time; the daily timing error of the electric energy meter and the timeout time are measured, and the high-precision local time is utilized to force the electric energy meter to synchronize with the local time for time calibration. According to the invention, benefits of an electric power department and electricity customers are ensured, a crystal oscillator and a load capacitor are matched through measurement of daily timing errors, and more accurate matching parameters are obtained; the two paths of electric energy meters are simultaneously connected, so that the test efficiency is improved, qualified products are screened more quickly, the problem that a user misconnects a 220V power supply to a test port is effectively prevented, a core circuit of equipment is fully protected, the failure rate of the equipment is practically and effectively reduced, and good use experience is provided for a user.

Description

Technical Field

[0001] The present invention relates to the technical field of timing and synchronization, and in particular to an on-site detection method and system for an electric energy meter and a metering terminal clock. Background Art

[0002] Electricity meter measurement plays an important role in current power work. Whether its clock is accurate directly affects the settlement of rates and is related to the interests of both parties involved in the power supply.

[0003] With the continuous development of the power industry, electric energy metering has become an important link in the power marketing system. At present, the clock deviation problem is a major problem affecting the accuracy of electric energy meter measurement. Only by effectively controlling the clock deviation and improving its accuracy can the safe operation of the electric energy meter be maintained and its accurate measurement function be exerted. Therefore, it is necessary for power supply companies to strive for excellence, clarify the causes and influencing factors of clock deviation, explore treatment measures, further improve the calibration quality, ensure that the electric energy meter measurement is more accurate and the operation is more reliable, and protect the economic interests of both the power supply and the power user.

[0004] Domestic meter timing methods are divided into two types: independent clock chips and single-chip integrated clock modules. The latter has greater cost advantages than the former, so it is more widely used. The single-chip integrated clock module mainly provides clock services. Users can set and read the internal timing register values. After the user sets it, it can automatically time, and generally output clock pulses in seconds. Crystal oscillator devices below 20MHz have good stability; those above 20MHz are mostly harmonics with poor stability. The clock module of the energy meter is powered by a battery in a power outage. In order to achieve low-power and stable operation, the clock module clock source can only select a low-frequency crystal oscillator with a small drive current. The tuning fork crystal oscillator frequency is usually between 10 and 200kHz, and the generally used frequency is 32.768KHz.

[0005] The factors that affect the timing accuracy of the electric energy meter mainly include: crystal oscillator, matching capacitor, battery and so on.

[0006] ① Crystal oscillator: The oscillation frequency of a quartz crystal oscillator changes with temperature, which is called temperature characteristics. Due to this characteristic, the accuracy of the clock chip will shift with temperature changes, and different crystal oscillators have different temperature characteristics. Through batch testing, the deviation of different crystal vertices is large, which needs to be measured during calibration and compensated according to the deviation to maintain the accuracy of the clock chip.

[0007] ② Matching capacitor: The actual oscillation frequency of a passive crystal oscillator depends not only on the crystal oscillator itself, but also on the size of the matching capacitor. The matching capacitor needs to be finely adjusted to ensure that the clock runs within the allowable error.

[0008] ③Battery: Battery is also one of the important factors causing deviation. The clock battery of the energy meter is used to power the RTC (real-time clock module). When powered by an external power supply, the battery voltage is generally 3.3V (or 5V). According to the current actual usage, the Southern Power Grid Company stipulates that the battery voltage can be used normally under normal conditions if it exceeds 2.7V. When the battery voltage is lower than 2.7V, the accumulated time stamp of the energy meter will be wrong, and the battery needs to be replaced. After replacing the battery, the clock needs to be recalibrated and the relevant data lost by the energy meter needs to be processed.

[0009] In order to solve the problem of measuring the timing error of the electricity meter, a device with daily timing error detection and timeout time measurement has been developed. The device can measure the daily timing error of the electricity meter, and can test the number of timeout days according to the timeout time set by the user, and further give suggestions for replacing the meter or calibrating the time. At the same time, the device integrates the broadcast time calibration function of the DLT645-2007 State Grid multi-function electricity meter communication protocol, which is convenient for users to calibrate the electricity meter and further realize the intelligent management of the electricity meter clock calibration. Summary of the invention

[0010] In view of the above existing problems, the present invention aims at the situation that the power meter may time out again when it is in time synchronization, and on-site operation and maintenance are required, which increases the number of personnel operation and maintenance. The device checks whether the clock of the power meter meets the specified requirements, and gives a prediction of how long it is likely to occur when the clock timeout occurs. It determines whether to replace the power meter based on the inspection, reduces the number of operation and maintenance times for on-site handling of clock anomalies, and ensures that the clock out-of-tolerance problem does not occur in a short time after the on-site handling of the clock anomaly is completed.

[0011] In order to solve the above technical problems, a field detection method for electric energy meter and metering terminal clock is proposed, including:

[0012] Build a clock calibrator GPS-7A system and intercept high-voltage signals for overload protection during data collection; convert the optocoupler on-off signal output by the electric energy meter into a recognizable electrical signal, and use the GPS & Beidou receiver to obtain the standard time; measure the daily timing error and timeout time of the electric energy meter, and use the high-precision local time to force the electric energy meter to synchronize with the local time for time calibration.

[0013] As a preferred solution of the on-site detection method of the electric energy meter and the metering terminal clock described in the present invention, the overload protection includes: using 2-way electric energy meter optocoupler output signal access, when the 220V industrial frequency AC power is connected to the instrument input port, the instrument protection module is started, the forward voltage is intercepted by the high-voltage diode, and reversely connected to the signal input end, and a current limiting resistor and a voltage regulator diode are added after the high-voltage diode. When the industrial frequency 220V negative half-cycle voltage enters the input port, the instrument protection module limits the current through the current limiting resistor, and the voltage regulator diode limits the amplitude before entering the shaping circuit.

[0014] When the optocoupler output of the energy meter is correctly connected to the instrument input terminal, the optocoupler inside the energy meter will output a 1Hz on-off signal. When the optocoupler output of the energy meter is on, the signal is shaped into a square wave and sent to the MCU for sampling and calculation.

[0015] As a preferred solution of the on-site detection method of the electric energy meter and the metering terminal clock described in the present invention, the signal shaping includes converting the 1Hz optocoupler on-off signal output by the electric energy meter into an LVTTL3.3V electrical signal recognizable by the MCU, and placing the positive voltage of the operational amplifier on both sides of the negative input reference voltage when the optocoupler is turned on and off.

[0016] When the optocoupler of the energy meter outputs a connection signal, when the voltage is lower than 7V, the operational amplifier outputs a low level. When the optocoupler of the energy meter outputs a disconnection signal, when the voltage is higher than 7V, the operational amplifier outputs a high level, and uses a resistor network for voltage division to obtain an LVTTL 3.3V electrical signal, which is sent to the MCU capture port.

[0017] As a preferred solution of the on-site detection method of the electric energy meter and metering terminal clock described in the present invention, the standard time includes: using a GPS & Beidou receiver to obtain the standard time, adding the rising edge of the PPS signal to mark the whole second of UTC, receiving the beacon information sent by the GPS interval with extremely high precision time difference through the Receiver, and counting the ticks of its own clock within the specified time. After the Receiver is synchronized with the GPS clock, it outputs the PPS signal and the complete clock waveform every second according to its own calibrated clock, and synchronizes and locks all clocks in the computer.

[0018] As a preferred solution of the on-site detection method of the electric energy meter and the metering terminal clock of the present invention, the measurement of the daily timing error and the measurement of the timeout time include: the MCU samples the signal output by the signal shaping, counts by controlling the counter, obtains the count value of the standard time pulse within a signal cycle, and the microprocessor collects and calculates the daily timing error:

[0019]

[0020] Where Dd is the standard daily difference value, f0 is the nominal value of the center frequency of the daily difference signal, and f1 is the actual frequency value of the signal being tested.

[0021] The MCU samples the shaped second pulse electrical signal, records and saves the two rising edges of a complete second pulse cycle, and uses the MCU counter to capture the timer value N1 when the first rising edge of the second pulse arrives and the counter value N2 when the second rising edge of the second pulse arrives. Then N2-N1 is the total number of counter counts between the two rising edges of the second pulse.

[0022] If the MCU sampling frequency is F, then the time interval between each count is 1 / F seconds, and the time interval between the rising edges of the two pulses actually sampled is seconds, the corresponding frequency is

[0023] Calculate the timeout period Td:

[0024]

[0025] Among them, T curr is the current clock reading, γ is the rate of controlling exponential decay, T is the time variable, and Θ(Dd) is the adjustment for the daily timing error.

[0026] Based on the time timing error tested, GPS-7A determines whether to replace the watch. When Dd≤0.5s / d, it is recommended not to replace the watch.

[0027] However, if Dd>0.5s / d, the timeout time Td is calculated and displayed according to the timeout parameter set by the user. When Td≤the timeout parameter set by the user, it is recommended not to change the meter. When Td>the timeout parameter set by the user, it is recommended to change the meter.

[0028] As a preferred solution of the on-site detection method of the electric energy meter and the metering terminal clock of the present invention, the time calibration includes: the time calibration module of the GPS-7A clock calibrator adopts two time calibration schemes, infrared time calibration and RS485 time calibration, and monitors the surrounding environment conditions in real time through sensors to evaluate the current time calibration environment:

[0029]

[0030] Where k is the weight coefficient of the obstacle's impact on the signal, a is the distance between the device and the timing source, ob is the number of obstacles that block the signal in the path, and s is the measured GPS / Beidou signal strength.

[0031] Based on the environmental assessment results, select the time calibration method: when E>1, select infrared time calibration and use infrared signals for time calibration to ensure that there are no significant obstacles between the two devices.

[0032] When E≤1, select RS485 time calibration to calibrate the time in the case of signal interference or long distance.

[0033] After selecting the time adjustment scheme, update the time to calculate the time deviation and synchronize the time.

[0034] Another object of the present invention is to provide an on-site detection system for an electric energy meter and a metering terminal clock. The present invention solves the problem of how to protect the equipment ports and personnel safety, avoid equipment damage and personal injury caused by wiring errors or misconnection of voltage lines, and improves the problem of how to improve the timing accuracy of the electric energy meter clock and reduce daily timing errors. It solves the problems of insufficient equipment protection, low timing accuracy, low time calibration efficiency and complex operation in the prior art, thereby ensuring the fairness and reliability of electricity metering and improving the system's operational convenience and human-computer interaction experience.

[0035] As a preferred solution of the electric energy meter and metering terminal clock field detection system described in the present invention, it is characterized by including a signal preprocessing module, a daily timing error / timeout time measurement module, and a time calibration module.

[0036] The signal preprocessing module completes the equipment port input protection, the electric energy meter optocoupler output signal shaping, and the GPS & Beidou receiver standard second pulse signal acquisition.

[0037] The daily timing error / timeout measurement module performs measurement based on the four 1 Hz test signals obtained by the signal preprocessing module to obtain the daily timing error and timeout.

[0038] The timing module outputs a broadcast timing instruction that complies with the DLT645-2007 State Grid multi-function electric energy meter communication protocol, including an infrared mode and an RS485 mode.

[0039] As a preferred solution of the on-site detection system of the electric energy meter and metering terminal clock described in the present invention, the signal preprocessing module includes an antenna interface and Beidou & GPS timing unit and an electric energy meter optical coupler input shaping and input protection unit. The antenna interface and Beidou & GPS timing unit obtain standard time through GPS satellite and Beidou satellite synchronization, and complete the time synchronization and clock verification function for the electric energy meter. The electric energy meter optical coupler input shaping and input protection unit performs second pulse input access of four electric energy meters. The second pulse output of the electric energy meter is an unconventional electrical signal, which is an optical coupler output. The optical coupler output signal is converted into an electrical signal for measurement. When there is a wiring error and a misconnection of the voltage line, the equipment and personnel are protected to prevent the equipment from being damaged.

[0040] The daily timing error / timeout measurement module includes a high-precision temperature-compensated crystal oscillator unit that uses a high-stability, high-frequency standard pulse signal to send to the MCU and the second pulse signal of the electric energy meter for calculation and processing to determine the daily timing error and timeout days of the electric energy meter.

[0041] The timing module includes a central processing unit and a data operation unit, an interaction unit, a display unit, an output unit and a power supply management unit. The central processing unit & data operation uses a 32-bit high-frequency processor to analyze data and communicate between modules. The interaction unit is the input interface of the device, and the test parameters are selected through the touch screen. The display unit is used to display the device test mode, measurement results, and complete the human-computer dialogue function. The output unit outputs 10MHz, 1MHz, 1kHz, and 1Hz signals. The power supply management unit serves as the power unit of the device and provides power for the device.

[0042] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of the on-site detection method of the electric energy meter and the metering terminal clock are implemented.

[0043] A computer-readable storage medium stores a computer program thereon, characterized in that when the computer program is executed by a processor, the steps of the on-site detection method of the electric energy meter and the metering terminal clock are implemented.

[0044] Beneficial effects of the invention: The invention combines microprocessor technology and digital signal processing technology to realize the measurement of daily timing error and timeout time of electric energy meter, and the timeout time parameter can be set by the user. As a fully digital, multi-functional, high-precision, intelligent multi-parameter time error measurement device, it provides technical support and guarantee for the research and development of electric energy meter manufacturers and batch detection of electric energy meters, and provides objective and fair basis for power departments and electricity users, while ensuring the interests of power departments and electricity users.

[0045] During the R&D and production stage of the energy meter, the daily timing error can be measured to match the crystal oscillator and load capacitance to obtain more accurate matching parameters; during the batch testing stage, the simultaneous access of two energy meters can greatly improve the test efficiency and screen qualified products more quickly; front-line power grid workers can simultaneously complete daily timing error testing, timeout time testing, energy meter calibration and other tasks to improve test efficiency.

[0046] It effectively prevents users from mistakenly connecting the 220V power supply to the test port, fully protects the core circuit of the equipment, effectively reduces the equipment failure rate, and provides users with a good user experience.

[0047] The test results are displayed in a very intuitive and concise way. There is no need for complicated and tedious operations. The learning cost is low and it is easy to get started. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0049] Figure 1 A mobile inspection flow chart of an on-site detection method for an electric energy meter and a metering terminal clock provided by an embodiment of the present invention.

[0050] Figure 2 The invention provides signals and modulation of an electric energy meter and a method for detecting a clock on-site of a metering terminal in accordance with an embodiment of the present invention.

[0051] Figure 3 The light radiation angle of an electric energy meter and a metering terminal clock field detection method provided by an embodiment of the present invention.

[0052] Figure 4 A system solution module diagram of an electric energy meter and metering terminal clock field detection system provided by an embodiment of the present invention.

[0053] Figure 5 A system interface structure diagram of an electric energy meter and metering terminal clock field detection system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0056] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0057] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0058] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides an on-site detection method for an electric energy meter and a metering terminal clock, comprising:

[0061] S1: Build the clock calibrator GPS-7A system and intercept the high voltage signal for overload protection during data collection.

[0062] Furthermore, a two-way electric energy meter optocoupler output signal is used for access. When the 220V industrial frequency AC power is connected to the instrument input port, the instrument protection module is started, the forward voltage is intercepted by the high-voltage diode, and reversely connected to the signal input terminal. A current limiting resistor and a voltage regulator diode are added after the high-voltage diode. When the industrial frequency 220V negative half-cycle voltage enters the input port, the instrument protection module limits the current through the current limiting resistor and the voltage regulator diode limits the amplitude before entering the shaping circuit.

[0063] Supports 2-way access to the optocoupler output signal of the energy meter to improve the test efficiency. Conventional equipment for testing the daily timing error of the energy meter is connected to one energy meter, which has low test efficiency. At the same time, through the GPS & Beidou timing module, the standard Beijing time is synchronously displayed, and the clock timing error of the energy meter can be observed in real time.

[0064] First, the forward voltage is intercepted by a high-voltage diode. Here, a high-voltage diode with a withstand voltage of 700V is selected and connected in reverse to the signal input terminal. This ensures that the 220V power frequency positive half-cycle high voltage cannot enter the instrument, and only the negative half-cycle high voltage can enter the device. The selection parameters of the high-voltage diode here leave a margin. The peak value of the 220V power frequency voltage is 220*1.414=311V. Even if the energy meter is powered by 380V, the peak value is 380*1.414=537V, which is also within the range of 700V withstand voltage and can also play a role in circuit protection.

[0065] Secondly, add a current limiting resistor and a voltage regulator diode after the high-voltage diode. When the negative half-cycle voltage of the power frequency 220V enters the input port, the module is limited by the current limiting resistor and the voltage regulator diode before entering the shaping circuit. In this way, the voltage obtained by the negative half-cycle voltage of the power frequency 220V entering the post-stage signal shaping circuit is only the voltage drop of the diode 0.6V. At this time, the negative half-cycle power frequency voltage of 220V is added to the current limiting resistor, so it will not cause damage to the shaping circuit and MCU, thus playing a protective role.

[0066] When the optocoupler output of the energy meter is correctly connected to the instrument input terminal, the optocoupler inside the energy meter will output a 1Hz on-off signal. When the optocoupler output of the energy meter is on, the signal is shaped into a square wave and sent to the MCU for sampling and calculation.

[0067] Conventional test circuits can only accept low-voltage input, at the volt level. According to the previous summary of equipment failures for testing daily timing errors of energy meters, more than 90% of the failures are caused by operator misoperation. The energy meter has a 220V AC interface, which can easily touch the input end of the equipment, causing the MCU port and the shaping circuit to burn out. Through the clever design of the protection circuit, when the test port accidentally touches the 220V industrial frequency AC, the high-voltage signal is intercepted in the protection circuit part, and cannot enter the shaping circuit and MCU port, thereby protecting the core circuit.

[0068] It should be noted that the 1Hz optocoupler on-off signal output by the energy meter is converted into an LVTTL3.3V electrical signal recognizable by the MCU, and the on-off circuit of the optocoupler output of the energy meter is used to control the positive voltage of the operational amplifier. The design ensures that the positive voltage of the operational amplifier is on both sides of the negative input reference voltage when the optocoupler is turned on and off.

[0069] When the optocoupler of the energy meter outputs a connection signal, when the voltage is lower than 7V, the operational amplifier outputs a low level. When the optocoupler of the energy meter outputs a disconnection signal, when the voltage is higher than 7V, the operational amplifier outputs a high level, and uses a resistor network for voltage division to obtain an LVTTL 3.3V electrical signal, which is sent to the MCU capture port.

[0070] S2: Convert the optocoupler on / off signal output by the energy meter into a recognizable electrical signal, and use the GPS & Beidou receiver to obtain the standard time.

[0071] Furthermore, GPS & Beidou receivers are used to obtain standard time, and the rising edge of the PPS signal is added to mark the whole second of UTC, with an accuracy of nanoseconds and no cumulative error. GPS uses atomic clocks, a device that uses extremely stable electromagnetic waves emitted by atoms when they absorb or release energy to keep time, with an accuracy of 1 second every 20 million years.

[0072] The receiver receives the beacon information sent by the GPS at extremely high precision time difference intervals, counts the ticks of its own clock within the specified time, compares the count value with the theoretical number of ticks generated in the same period of time under the nominal frequency, and uses hardware to "return more and supplement less" on its own crystal oscillator frequency to achieve its own precise frequency correction within a few consecutive second pulse cycles. After the receiver is synchronized with the GPS clock, it outputs the PPS signal and the complete clock waveform every second according to its own calibrated clock, and synchronizes and locks all clocks in the computer.

[0073] In order to obtain highly accurate and more stable PPS second pulses, imported UBLOX receiving modules are used, and active antennas are selected to enhance signal reception capabilities. GPS & Beidou modules are outdoor working modules, which are very weak indoors and have poor effects. The handheld device needs to be taken to an open outdoor place for time synchronization to better obtain GPS & Beidou signals.

[0074] The GPS-7A clock calibrator also provides a more intuitive time difference measurement method. The device can directly obtain the real-time time information of the electric energy meter from the electric energy meter using infrared communication and display it on the 4.3-inch touch screen. In this way, the standard time on the clock calibrator and the actual time on the electric energy meter to be tested can be compared by intuitive observation to obtain the time error value.

[0075] S3: Measure the daily timing error and timeout time of the electric energy meter, and use the high-precision local time to force the electric energy meter to synchronize with the local time for time calibration.

[0076] Furthermore, the MCU samples the signal output by the signal shaping, counts by controlling the counter, obtains the count value of the standard time pulse within a signal cycle, and is collected by the microprocessor to calculate the daily timing error:

[0077]

[0078] Where Dd is the standard daily difference value, f0 is the nominal value of the center frequency of the daily difference signal, and f1 is the actual frequency value of the signal being tested.

[0079] The MCU samples the shaped second pulse electrical signal, records and saves the two rising edges of a complete second pulse cycle, and uses the MCU counter to capture the timer value N1 when the first rising edge of the second pulse arrives and the counter value N2 when the second rising edge of the second pulse arrives. Then N2-N1 is the total number of counter counts between the two rising edges of the second pulse.

[0080] If the MCU sampling frequency is F, then the time interval between each count is 1 / F seconds, and the time interval between the rising edges of the two pulses actually sampled is seconds, the corresponding frequency is

[0081] Calculate the timeout period Td:

[0082]

[0083] Among them, T curr is the current clock reading, γ is the rate of controlling exponential decay, T is the time variable, and Θ(Dd) is the adjustment for the daily timing error.

[0084]

[0085] Among them, T interval is the actual time interval, P(t) is the function of controlling external disturbance, and G(t) is the time rate of change.

[0086]

[0087] Among them, λ is the parameter of filtering degree, which determines the degree of error smoothing.

[0088] Based on the time timing error tested, GPS-7A determines whether to replace the watch. When Dd≤0.5s / d, it is recommended not to replace the watch.

[0089] However, if Dd>0.5s / d, the timeout time Td is calculated and displayed according to the timeout parameter set by the user. When Td≤the timeout parameter set by the user, it is recommended not to change the meter. When Td>the timeout parameter set by the user, it is recommended to change the meter.

[0090] It should be noted that the GPS-7A clock calibrator's time calibration module uses both infrared time calibration and RS485 time calibration. It uses sensors to monitor the surrounding environment in real time and evaluate the current time calibration environment:

[0091]

[0092] Where k is the weight coefficient of the obstacle's impact on the signal, a is the distance between the device and the timing source, ob is the number of obstacles that block the signal in the path, and s is the measured GPS / Beidou signal strength.

[0093] Based on the environmental assessment results, select the time calibration method: when E>1, select infrared time calibration and use infrared signals for time calibration to ensure that there are no significant obstacles between the two devices.

[0094] When E≤1, select RS485 time calibration to calibrate the time in the case of signal interference or long distance.

[0095] After selecting the time calibration scheme, update the time:

[0096] T new =T curr +(T source -T curr )·α

[0097] Among them, T new is the updated time, T curr is the current time, T source is the source time, represents the reference target time, and α is the weight coefficient that controls the smoothness of the update.

[0098] Record the current time of the energy meter and calculate the deviation:

[0099] ΔT=T new -(T source -T curr )·(1-β)

[0100] Among them, ΔT represents the time deviation, that is, the difference between the updated time and the current time, and β is the adjustment coefficient.

[0101] The accuracy of the system's time calculation:

[0102]

[0103] Among them, Accuracy represents the accuracy of the computing system output, and factor is the adjustment coefficient that affects the accuracy assessment.

[0104] Example 2, reference Figure 2-Figure 3 , which is an embodiment of the present invention, provides a three-phase four-wire sensitivity calculation method for a low-voltage AC / DC distribution network. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0105] Infrared time calibration uses infrared transmitting and receiving heads to communicate with the electric energy meter and uses the broadcast time calibration scheme to calibrate the time.

[0106] ① Modulation characteristics

[0107] Signal modulation see Figure 2 , a is the unmodulated electrical signal, and b is the modulated infrared light signal.

[0108] The carrier frequency is 38kHz±1kHz.

[0109] ②Optical properties: Reference temperature is 23℃±2℃.

[0110] ③Light radiation half angle: θ≥15°.

[0111] ④ Wavelength: The wavelength of infrared light is 900nm~1000nm.

[0112] Transmitter: The irradiance of the infrared light signal generated by the transmitter on its optical axis at a distance of 1m±10mm from the transmitter surface:

[0113] ON state Ee / T ≥ 250μW / cm 2

[0114] The irradiance of the infrared light signal generated by the transmitter on its optical axis at a distance of 10mm±1mm from the transmitter surface is:

[0115] OFF state Ee / T≤1μW / cm 2

[0116] Receiver: The infrared light irradiance Ee / R of the receiver at a distance of 10mm±1mm from the receiver surface on its optical axis shall meet the following conditions:

[0117] ON state Ee / R ≥ 3.5μW / cm 2

[0118] OFF state Ee / R≤2μW / cm 2

[0119] ⑤ Light environment conditions: When the ambient light intensity around the optical path of data transmission is less than 5000lx, the effective communication distance is greater than 3m.

[0120] ⑥Electrical characteristics: Default rate: 1200bps.

[0121] The RS485 time synchronization scheme uses the RS485 interface to communicate with the electric energy meter, and also uses the broadcast scheme for time synchronization.

[0122] Consistent with the DLT645-2007 State Grid multi-function energy meter communication protocol, the GPS-7A clock calibrator uses the RS-485 standard serial electrical interface, making multi-point connection possible. The general performance of the RS-485 interface meets the following requirements:

[0123] Common mode input voltage: -7V~+12V.

[0124] Differential mode input voltage: greater than 0.2V.

[0125] Drive output voltage: When the load impedance is 54Ω, the maximum is 5V and the minimum is 1.5V.

[0126] Three-state output.

[0127] Half-duplex communication mode.

[0128] The driving capability is no less than 32 similar interfaces.

[0129] Default rate: 2400bps. When the communication rate is not more than 100kbps, the effective transmission distance is not less than 1200m.

[0130] The bus is passive and the isolated power supply is provided by the multi-function energy meter or data terminal.

[0131] The clock calibrator GPS-7A is specified in the following table:

[0132] Table 1

[0133]

[0134]

[0135] Embodiment 3, the third embodiment of the present invention, is different from the first two embodiments in that:

[0136] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

[0137] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0138] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0139] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0140] Example 4, reference Figure 4-Figure 5 , which is the fourth embodiment of the present invention, provides an electric energy meter and metering terminal clock field detection system, including a signal preprocessing module 10, a daily timing error / timeout time measurement module 20, and a time calibration module 30.

[0141] The signal preprocessing module 10 completes the device port input protection, the electric energy meter optocoupler output signal shaping, and the GPS & Beidou receiver standard second pulse signal acquisition.

[0142] The signal preprocessing module 10 includes an antenna interface and Beidou & GPS timing unit 11 and an electric energy meter optical coupler input shaping and input protection unit 12. The antenna interface and Beidou & GPS timing unit 11 obtain standard time through GPS satellite and Beidou satellite synchronization, and complete the synchronization and clock verification function for the electric energy meter. The electric energy meter optical coupler input shaping and input protection unit 12 performs second pulse input access of four electric energy meters. The second pulse output of the electric energy meter is an unconventional electrical signal as an optical coupler output. The optical coupler output signal is converted into an electrical signal for measurement. When there is a wiring error and a misconnection of the voltage line, the equipment and personnel are protected to prevent the equipment from being damaged.

[0143] The daily timing error / timeout measurement module 20 performs measurement based on the four 1 Hz test signals obtained by the signal preprocessing module 10 to obtain the daily timing error and timeout.

[0144] The daily timing error / timeout measurement module 20 includes a high-precision temperature-compensated crystal oscillator unit 21 which uses a high-stability, high-frequency standard pulse signal to send to the MCU and the second pulse signal of the electric energy meter for calculation and processing to determine the daily timing error and timeout days of the electric energy meter.

[0145] The time calibration module 30 outputs a broadcast time calibration instruction that complies with the DLT645-2007 State Grid multi-function electric energy meter communication protocol, including infrared mode and RS485 mode.

[0146] The timing module 30 includes a central processing unit and a data operation unit 31, an interaction unit 32, a display unit 33, an output unit 34 and a power supply management unit 35. The central processing unit & data operation unit 31 uses a 32-bit high-frequency processor to analyze data and communicate between modules. The interaction unit 32 is the input interface of the device, and the test parameters are selected through the touch screen. The display unit 33 is used to display the device test mode, measurement results, and complete the human-computer dialogue function. The output unit 34 outputs 10MHz, 1MHz, 1kHz, and 1Hz signals. The power supply management unit 35 serves as the power unit of the device to provide power for the device.

[0147] Among them, the system interface is as follows Figure 4 As shown:

[0148] 1 is the power switch: used to turn the GPS-7A clock calibrator on or off.

[0149] 2 is the Type C charging port: used to charge the internal battery of the GPS-7A clock calibrator.

[0150] 3 is the infrared communication interface: used for infrared time calibration of electric energy meters.

[0151] 4 is the GPS & Beidou antenna interface: used to connect the GPS & Beidou antenna to synchronize the internal real-time clock.

[0152] 5 is the 1-channel signal input port: used to connect the 1Hz output of the electric energy meter optocoupler of the first channel.

[0153] 6 is a 2-channel signal input port: used to connect the second channel's electric energy meter optocoupler 1Hz output.

[0154] 7 is the 2-channel ground wire interface: used to connect the 1Hz output ground wire of the electric energy meter optocoupler of the second channel.

[0155] 8 is the 1-channel ground wire interface: used to connect the 1Hz output ground wire of the electric energy meter optocoupler of the first channel.

[0156] 9 is the 485 communication B interface: connected to the 485 communication B interface of the energy meter, used for 485 time calibration.

[0157] 10 is 485 communication A interface: connected to the 485 communication A interface of the energy meter, used for 485 time calibration.

[0158] 11 is PPS signal output: outputs 1PPS signal of GPS & Beidou module for measurement verification.

[0159] 12 is the ground wire interface: the ground wire end of the output signal.

[0160] 13 is the 10MHz output port: outputs 10MHz signal for measurement verification.

[0161] 14 is the 1MHz output port: outputs 1MHz signal for measurement verification.

[0162] 15 is 1KHz output port: output 1KHz signal for measurement verification.

[0163] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for on-site detection of electric energy meters and metering terminal clocks, characterized in that: include, Build the GPS-7A system for clock calibration instrument and intercept high voltage signals for overload protection during data collection; Convert the optocoupler on / off signal output by the energy meter into a recognizable electrical signal, and use the GPS & Beidou receiver to obtain the standard time; The daily timing error and timeout time of the electric energy meter are measured, and the high-precision local time is used to force the electric energy meter to synchronize with the local time for time calibration.

2. The method for on-site detection of the electric energy meter and the metering terminal clock according to claim 1, characterized in that: The overload protection includes: using 2-way electric energy meter optocoupler output signal access, when 220V industrial frequency AC power is connected to the instrument input port, the instrument protection module is started, the forward voltage is intercepted by the high-voltage diode, and the reverse voltage is connected to the signal input end, and a current limiting resistor and a voltage regulator diode are added after the high-voltage diode. When the industrial frequency 220V negative half-cycle voltage enters the input port, the instrument protection module limits the current through the current limiting resistor, and the voltage regulator diode limits the amplitude before entering the shaping circuit; When the optocoupler output of the energy meter is correctly connected to the instrument input terminal, the optocoupler inside the energy meter will output a 1Hz on-off signal. When the optocoupler output of the energy meter is on, the signal is shaped into a square wave and sent to the MCU for sampling and calculation.

3. The method for on-site detection of the electric energy meter and the metering terminal clock according to claim 2, characterized in that: The signal shaping includes converting the 1Hz optocoupler on / off signal output by the electric energy meter into an LVTTL 3.3V electrical signal recognizable by the MCU, and placing the positive voltage of the operational amplifier on both sides of the negative input reference voltage when the optocoupler is turned on and off; When the optocoupler of the energy meter outputs a connection signal, when the voltage is lower than 7V, the operational amplifier outputs a low level; when the optocoupler of the energy meter outputs a disconnect signal, when the voltage is higher than 7V, the operational amplifier outputs a high level, and uses a resistor network for voltage division to obtain an LVTTL3.3V electrical signal, which is sent to the MCU capture port.

4. The method for on-site detection of the electric energy meter and the metering terminal clock according to claim 3, characterized in that: The standard time includes using GPS & Beidou receivers to obtain standard time, adding the rising edge of the PPS signal to mark the whole second of UTC, receiving the beacon information sent by the GPS interval with extremely high precision time difference through the Receiver, and counting the ticks of its own clock within the specified time. After the Receiver is synchronized with the GPS clock, it outputs the PPS signal and the complete clock waveform every second according to its own calibrated clock and synchronizes and locks all clocks in the computer.

5. The method for on-site detection of the electric energy meter and the clock of the metering terminal according to claim 4, characterized in that: The measurement of the daily timing error and the measurement of the timeout period include: the MCU samples the signal output by the signal shaping, counts by controlling the counter, obtains the count value of the standard time pulse in one signal cycle, and the microprocessor collects and calculates the daily timing error: Where Dd is the standard daily difference value, f0 is the nominal value of the center frequency of the daily difference signal, and f1 is the actual frequency value of the signal being tested; MCU samples the shaped second pulse electrical signal, records and saves the two rising edges of a complete second pulse cycle, and uses the MCU counter to capture the timer value N1 when the first rising edge of the second pulse arrives and the counter value N2 when the second rising edge of the second pulse arrives. Then N2-N1 is the total number of counter counts between the two rising edges of the second pulse. If the MCU sampling frequency is F, then the time interval between each count is 1 / F seconds, and the time interval between the rising edges of the two pulses actually sampled is The corresponding frequency is Calculate the timeout period Td: Among them, T curr is the current clock reading, γ is the rate of controlling exponential decay, T is the time variable, and Θ(Dd) is the adjustment for the daily timing error; Based on the time error measured, GPS-7A determines whether to replace the watch. If Dd≤0.5s / d, it is recommended not to replace the watch. However, if Dd>0.5s / d, the timeout time Td is calculated and displayed according to the timeout parameter set by the user. When Td≤the timeout parameter set by the user, it is recommended not to change the meter. When Td>the timeout parameter set by the user, it is recommended to change the meter.

6. The method for on-site detection of the electric energy meter and the metering terminal clock according to claim 5, characterized in that: The time calibration includes that the time calibration module of the GPS-7A clock calibrator adopts two time calibration schemes, namely infrared time calibration and RS485 time calibration, and monitors the surrounding environment conditions in real time through sensors to evaluate the current time calibration environment: Where k is the weight coefficient of the obstacle's impact on the signal, a is the distance between the device and the timing source, ob is the number of obstacles that block the signal in the path, and s is the measured GPS / Beidou signal strength; Based on the environmental assessment results, select the time calibration method: when E>1, select infrared time calibration, use infrared signals for time calibration, and ensure that there are no significant obstacles between the two devices; When E≤1, select RS485 time calibration to calibrate the time in the case of signal interference or long distance; After selecting the time adjustment scheme, update the time to calculate the time deviation and synchronize the time.

7. A system using the electric energy meter and metering terminal clock on-site detection method according to any one of claims 1 to 6, characterized in that: It includes signal preprocessing module, daily timing error / timeout measurement module and time calibration module; The signal preprocessing module completes the device port input protection, the electric energy meter optocoupler output signal shaping, and the GPS & Beidou receiver standard second pulse signal acquisition; The daily timing error / timeout measurement module measures the four 1Hz test signals obtained by the signal preprocessing module to obtain the daily timing error and timeout time; The timing module outputs a broadcast timing instruction that complies with the DLT645-2007 State Grid multi-function electric energy meter communication protocol, including an infrared mode and an RS485 mode.

8. The method for on-site detection of the electric energy meter and the metering terminal clock according to claim 7, characterized in that: The signal preprocessing module includes an antenna interface and Beidou & GPS timing unit and an electric energy meter optical coupler input shaping and input protection unit. The antenna interface and Beidou & GPS timing unit synchronize the time through GPS satellites and Beidou satellites to obtain standard time, and complete the synchronization and clock verification functions for the electric energy meter; the electric energy meter optical coupler input shaping and input protection unit performs second pulse input access of four electric energy meters. The second pulse output of the electric energy meter is an unconventional electrical signal as an optical coupler output, and the optical coupler output signal is converted into an electrical signal for measurement. When a wiring error or a misconnection of a voltage line occurs, the equipment and personnel are protected to prevent the equipment from being damaged; The daily timing error / timeout measurement module includes a high-precision temperature-compensated crystal oscillator unit that uses a high-stability, high-frequency standard pulse signal to send to the MCU and the second pulse signal of the electric energy meter for calculation and processing to determine the daily timing error and timeout days of the electric energy meter; The timing module includes a central processing unit and a data operation unit, an interaction unit, a display unit, an output unit and a power supply management unit. The central processing unit & data operation uses a 32-bit high-frequency processor to analyze data and perform inter-module communication; the interaction unit is the input interface of the device, and the test parameters are selected through the touch screen; the display unit is used to display the device test mode, measurement results, and complete the human-computer dialogue function; the output unit outputs 10MHz, 1MHz, 1kHz, and 1Hz signals; the power supply management unit serves as the power unit of the device to provide power for the device.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the on-site detection method for the electric energy meter and the metering terminal clock according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the on-site detection method of the electric energy meter and the metering terminal clock according to any one of claims 1 to 6 are implemented.

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