An online metering method and system for standard time and frequency terminals in an electrical energy testing device.

Abstract

This invention belongs to the field of time and frequency, and discloses an online metering method and system for standard time and frequency terminals in an electrical energy testing device. Based on the metering mode of the standard time and frequency terminal, the topology of the time and frequency transmission system is identified; based on the topology of the time and frequency transmission system, the direct channel of the optical splitter is automatically selected to achieve automatic online metering of each standard time and frequency terminal; after selecting the direct channel of the optical splitter, the device enters the time synchronization mode of the standard time and frequency terminal, and performs bidirectional time signal transmission by combining the standard IRIG-B code and the designed uplink code to achieve nanosecond-level time deviation measurement.

Description

Technical Field

[0001] This invention belongs to the field of time and frequency, and specifically relates to an online metering method and system for a standard time and frequency terminal in an electrical energy testing device. Background Technology

[0002] Time and frequency synchronization plays a crucial role in fields such as power, communications, finance, and national defense. The second is also an important physical quantity in the International System of Units (SI), characterized by high precision and remote reproducibility. Currently, the power system has established a multi-level time and frequency synchronization system consisting of the State Grid, provincial grids, and power testing facilities. However, due to the large number of end-user devices and the complexity of timing methods, problems such as low precision, difficulty in conducting remote and online metering, and inconvenience in periodic verification still exist.

[0003] Currently, all electrical energy testing equipment includes a standard clock. These original standard clocks relied on crystal oscillators to generate the standard frequency, without outputting a time signal. Most regions still use the old metrological calibration method, disassembling the standard time and frequency terminal and sending it to the laboratory for calibration, which presents numerous problems.

[0004] (1) Disassembly and inspection required: After disassembly, the electricity metering device will not work, affecting work efficiency; (2) Long measurement time: Calibration takes a long time and requires a lot of manpower, which affects work efficiency; (3) Problems can only be found after calibration: The built-in temperature-controlled crystal oscillator of the time base source may have problems such as inaccuracy and aging. Periodic calibration on an annual basis cannot achieve quality control of the time base source and is difficult to meet the needs of the power company for periodic verification. (4) Unable to calibrate current time error: The current calibration specification lacks a calibration method for current time error, which cannot meet the time accuracy calibration requirements of multi-fee energy meters and charging piles. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an online metering method and system for standard time-frequency terminals in an electrical energy testing device. By intelligently identifying the system's topology, it automatically selects the direct path of the optical splitter, enabling automatic online metering of each standard time-frequency terminal. A special encoding method is used to transmit time signals bidirectionally, eliminating link delay and achieving high-precision time deviation measurement at the nanosecond level.

[0006] To achieve the above objectives, the present invention provides the following solution: An online metering method for a standard time-frequency terminal in an electrical energy testing device, the method comprising: Based on the metering mode of the standard time and frequency terminal, the topological relationship of the time and frequency transmission system is identified; Based on the topology of the time-frequency transmission system, the direct channel of the optical splitter is automatically selected to achieve automatic online metering of each standard time-frequency terminal; After selecting the direct channel of the optical splitter, it enters the time synchronization mode of the standard time and frequency terminal. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement.

[0007] Preferred methods for identifying the topological relationships of a time-frequency transfer system based on metering patterns include: The time tester transmits IRIG-B code timing signals through fiber optic links and optical splitters. The standard time and frequency terminal receives the IRIG-B code timing signals, performs time synchronization, and uploads the status, timing signals, and optical splitter channel number information to the first-layer optical splitter through the fiber optic loop. The time tester obtains the topology of the time and frequency transmission system from the first-layer optical splitter.

[0008] Preferably, after selecting the direct channel of the optical splitter, the system enters the timing mode and combines the standard IRIG-B code and the designed uplink code to perform bidirectional time signal transmission, thereby achieving nanosecond-level time deviation measurement. The transmitted whole second T1 is modulated onto the IRIG-B code timing signal and sent to the standard time frequency transmission terminal; The standard time-frequency terminal under test parses the received IRIG-B code and records the time T2 of the definite timing edge Pr in the received IRIG-B code; The standard time and frequency terminal under test modulates the timestamp information of T2 onto the uplink code, and at the next whole second T3, modulates it onto the IRIG-B code timing signal and transmits it again. The timing tester receives and parses the uplink code, and records the time T4 of the uplink code's precise timing edge Pr; Based on times T1, T2, T3, and T4, calculate the link time deviation between the time tester and the standard time-frequency terminal under test.

[0009] Preferably, the method for calculating the link time deviation between the time tester and the standard time-frequency terminal under test based on times T1, T2, T3, and T4 includes: .

[0010] The present invention also provides an online metering system for a standard time and frequency terminal in an electrical energy testing device. The system is used to implement the aforementioned method and includes: an identification module, a gating module, and a transmission module. The identification module is used to identify the topological relationship of the time and frequency transmission system based on the metering mode of the standard time and frequency terminal. The selection module is used to automatically select the direct channel of the optical splitter based on the topology of the time-frequency transmission system, and to achieve automatic online metering of each standard time-frequency terminal. The transmission module is used to select the direct channel of the optical splitter and enter the timing mode of the standard time and frequency terminal. It combines the standard IRIG-B code and the designed uplink code to perform bidirectional time signal transmission and realize nanosecond-level time deviation measurement.

[0011] Preferred methods for identifying the topological relationships of a time-frequency transfer system based on metering patterns include: The time tester transmits IRIG-B code timing signals through fiber optic links and optical splitters. The standard time and frequency terminal receives the IRIG-B code timing signals, performs time synchronization, and uploads the status, timing signals, and optical splitter channel number information to the first-layer optical splitter through the fiber optic loop. The time tester obtains the topology of the time and frequency transmission system from the first-layer optical splitter.

[0012] Preferably, after selecting the direct channel of the optical splitter, it enters the timing mode. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement. The process includes: The transmitted whole second T1 is modulated onto the IRIG-B code timing signal and sent to the standard time frequency transmission terminal; The standard time-frequency terminal under test parses the received IRIG-B code and records the time T2 of the definite timing edge Pr in the received IRIG-B code; The standard time and frequency terminal under test modulates the timestamp information of T2 onto the uplink code, and at the next whole second T3, modulates it onto the IRIG-B code timing signal and transmits it again. The timing tester receives and parses the uplink code, and records the time T4 of the uplink code's precise timing edge Pr; Based on times T1, T2, T3, and T4, calculate the link time deviation between the time tester and the standard time-frequency terminal under test.

[0013] Preferably, the method for calculating the link time deviation between the time tester and the standard time-frequency terminal under test based on times T1, T2, T3, and T4 includes: .

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: Based on existing time and frequency transmission systems, this invention uses bidirectional transmission of special time codes to collect the system's topology, enabling automatic measurement of time and frequency deviations of hundreds of standard time and frequency terminals. This effectively solves the problem of performing automatic online measurements without disassembling the standard time and frequency terminals, improving work efficiency and saving on inspection costs. Attached Figure Description

[0015] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. 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 effort.

[0016] Figure 1 This is a schematic diagram illustrating the usage method of the standard time and frequency terminal in an electrical energy testing device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of an online metering method for a standard time and frequency terminal in an electrical energy testing device according to an embodiment of the present invention; Figure 3 This is a topology diagram of the time-frequency transfer system according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the method in an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Definitions of abbreviations and key terms Standard time and frequency terminal: A device that reproduces the time and frequency signal of a reference clock through optical fiber or other methods. It can be used in electricity meter testing equipment as a standard clock.

[0020] IRIG-B code: IRIG-B is a serial time code with a frame rate of 1 frame / second, capable of transmitting 100 bits of information. Year information is in binary-decimal format, and day time is in direct binary format. It is divided into unmodulated DC code (DC) and amplitude-modulated AC code (AC). DC code offers higher timekeeping accuracy, while AC code enables long-distance transmission.

[0021] Example 1 A standard time and frequency terminal is a standard clock with remote traceability capabilities. Currently, it mainly transmits the time and frequency signals of a reference clock remotely to the standard time and frequency terminal via optical fiber, and is primarily used in electrical energy testing equipment, such as manual testing benches and electricity meter calibration lines. This invention designs a time-coding method for time transmission between a time tester and a standard time and frequency terminal, enabling the standard time and frequency terminal to conduct remote online measurement without the need for traditional measurement methods that require moving the equipment to a metrology laboratory for on-site measurement.

[0022] The usage method of standard time and frequency terminals in electrical energy testing equipment is as follows: Figure 1 The reference clock is connected to an optical splitter via optical fiber. After passing through one or more optical splitters, the time-frequency signal is transmitted to a standard time-frequency terminal. Each standard time-frequency terminal provides a frequency signal for one energy meter testing station. Specifically: like Figure 2 , Figure 4 As shown, the present invention provides an online metering method for a standard time-frequency terminal in an electrical energy testing device, the method comprising: Based on the metering mode of the standard time and frequency terminal, the topological relationship of the time and frequency transmission system is identified; Based on the topology of the time-frequency transmission system, the direct channel of the optical splitter is automatically selected to achieve automatic online metering of each standard time-frequency terminal; After selecting the direct channel of the optical splitter, it enters the time synchronization mode of the standard time and frequency terminal. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement.

[0023] The specific implementation process is as follows: (1) The standard time and frequency terminal has two working modes: time synchronization mode and metering mode. In time synchronization mode, the time synchronization signal is transmitted downwards by the reference clock. In metering mode, the time synchronization signal is transmitted downwards by the time tester, and metering tests are performed on each standard time and frequency terminal, as follows. Figure 3 .

[0024] In metering mode, the time tester transmits IRIG-B code timing signals via fiber optic links and optical splitters. The standard time and frequency terminals receive these signals, decode them, and use the decoded 1PPS+TOD to discipline their built-in clocks, achieving time synchronization. Each standard time and frequency terminal uploads its own number, status, and other information to the optical splitter via a fiber optic loop. Information about the standard time and frequency terminals connected to each channel of the optical splitter, along with the splitter's own number and layer number, is also uploaded to the next higher-level optical splitter, and so on, until the first-layer (top-level) optical splitter. From the first-layer (top-level) optical splitter, the connection relationships of all standard time and frequency terminals and optical splitters can be obtained—that is, which layer the optical splitter is located on and which channel connects to which standard time and frequency terminal. Thus, the time tester obtains the topology diagram of the time and frequency transfer system (the connection relationship diagram between devices, such as...) from the first-layer optical splitter. Figure 3 (As shown).

[0025] (2) Based on the topology diagram, the time tester broadcasts downlink codes to all optical splitters. In metering mode, it sends software commands to open one channel on each optical splitter. Innovatively, it uses the IRIG-B format for encoding, transmitting the numbers of the direct-access optical splitter and the standard time-frequency terminal to the optical splitter in IRIG-B code form. The selected optical splitter opens its corresponding channel, while the unselected channel closes, ensuring a direct signal connection between the time tester and the standard time-frequency terminal under test. The downlink selection optical splitter encoding content is explained below.

[0026] P0[0]: Position separator. Its sequence number in the frame is 0; Pr[1]: Timing edge. Its sequence number in the frame is 1; P0[2:5]: Pass-through setting encoding identifier. Its sequence number in the frame is 2-5; P0[6:9]: Pass-through setting encoding identifier. Its sequence number in the frame is 6-9; P1[0]: Position separator P1. Its sequence number in the frame is 10; P1[1:9]: ID number of optical splitter 1. Its sequence number in the frame is 11-19; P2[0]: Position separator P2. Its sequence number in the frame is 20; P2[1:9]: ID number of optical splitter 1. Its sequence number in the frame is 21-29; P3[0]: Position separator P3. Its sequence number in the frame is 30; P3[1:9]: ID number of optical splitter 1. Its sequence number in the frame is 31-39; P4[0]: Position separator P4. Its sequence number in the frame is 40; P4[1:5]: ID number of optical splitter 1. Its sequence number in the frame is 41-45; P4[6:8]: Reserved position. Its sequence number in the frame is 46-48; P4[9]: Optical splitter 1 pass-through switching code. When the value is 1, optical splitter 1 is switched to pass-through. The sequence number in the frame is 49; P5[0]: Position separator P5. Its sequence number in the frame is 50; P5[1:9]: ID number of optical splitter 2. Its sequence number in the frame is 51-59; P6[0]: Position separator P6. Its sequence number in the frame is 60; P6[1:9]: ID number of optical splitter 2. Its sequence number in the frame is 61-69; P7[0]: Position separator P7. Its sequence number in the frame is 70; P7[1:9]: ID number of optical splitter 2. Its sequence number in the frame is 71-79; P8[0]: Position separator P8. Its sequence number in the frame is 80; P8[1:5]: ID number of optical splitter 2. Its sequence number in the frame is 81-85; P8[6:8]: Reserved position. Its sequence number in the frame is 86-88; P8[9]: Optical splitter 2 pass-through switching code. When the value is 1, optical splitter 2 is switched to pass-through. The sequence number in the frame is 89; P9[0]: Position separator P9. Its sequence number in the frame is 90; P9[1:4]: The direct connection channel number between the standard time-frequency terminal under test and optical splitter 1. When the value is n (1~16), the nth channel of optical splitter 1 is directly connected. The sequence number in the frame is 91-94; P9[5:8]: The direct connection channel number between the standard time-frequency terminal under test and optical splitter 2. When the value is m (1~16), the m-th channel of optical splitter 2 is directly connected. The sequence number in the frame is 95-98; P9

[99] : Reserved position. Its sequence number in the frame is 99.

[0027] (3) After the optical fiber link between the time tester and the standard time and frequency terminal under test is established, the time tester enters the measurement mode, modulates the sent whole second T1 onto the IRIG-B code timing signal, and sends it to the standard time and frequency terminal.

[0028] (4) The standard time and frequency terminal under test parses the received IRIG-B code according to the standard IRIG-B code format, disciplines the internal crystal oscillator, synchronizes the time of the standard time and frequency terminal with the time tester, and records the time T2 of the punctual edge Pr in the received IRIG-B code.

[0029] (5) The standard time and frequency terminal under test modulates the T2 timestamp information onto the uplink code, and modulates it onto the IRIG-B code timing signal at the next whole second T3 and sends it again. The uplink code content is described as follows.

[0030] P0[0]: Position separator P0. Its sequence number in the frame is 0; Pr[1]: Timing edge. Its sequence number in the frame is 1; P0[2:9]~P5[0:9]: Standard B code format, consistent with IRIG-B standard code. Sequence numbers in the frame are 20-59; P6[0]: Position separator P6. Its sequence number in the frame is 60; P6[1:4]: Control code. Its sequence number in the frame is 61-64; P6[5:9]: Time within T2 seconds, in ns. Its sequence number in the frame is 65-69; P7[0]: Position separator P7. Its sequence number in the frame is 70; P7[1:9]: Time within T2 seconds, in ns. Its sequence number in the frame is 71-79; P8[0]: Position separator P8. Its sequence number in the frame is 80; P8[1:9]: Time within T2 seconds, in ns. Its sequence number in the frame is 81-89; P9[0]: Position separator P9. Its sequence number in the frame is 90; P9[1:9]: Time within T2 seconds, in ns. Its sequence number in the frame is 91-99.

[0031] (6) The time tester receives and parses the uplink code (the parsing process is the same as that of IRIG-B time code parsing), and records the time T4 of the uplink code punctual edge Pr.

[0032] (7) Since the uplink and downlink channels of the link between the time tester and the standard time-frequency terminal under test have the same delay, the time deviation between the two can be calculated using the following formula: (8) The time tester measures the time deviation sequence over a period of time. We perform a least-squares linear fit, and the slope of the line is the frequency deviation.

[0033] (9) The time tester usually uses the IRIG-B code timing protocol to synchronize with the standard time and frequency terminal. In addition to the downlink timing code being exactly the same as the standard IRIG-B, the same features are: one frame is transmitted per second, one frame of serial code contains 100 code elements, each code element occupies 10ms time, the basic code elements include “0” code element, “1” code element, and “P” code element, which correspond to pulse widths of 2ms, 5ms and 8ms respectively, where “P” code element is the position code element.

[0034] The difference lies in the fact that the uplink code and the standard IRIG-B code have different information content. The uplink code carries the time when the standard time-frequency terminal receives the IRIG-B code. At the same time, since time T3 is the next whole second after T2, it can be used for online measurement and testing.

[0035] In the automatic verification production lines of electricity meters in multiple power company metering centers, each testing station is equipped with a standard time and frequency terminal. Through the Type II satellite common-view system, time and frequency signals are transmitted to it via optical fiber. Through this invention, online metering calibration can be achieved.

[0036] Example 2 The present invention also provides an online metering system for a standard time and frequency terminal in an electrical energy testing device. The system is used to implement the method described in Embodiment 1. The system includes: an identification module, a gating module, and a transmission module. The identification module is used to identify the topology of the time and frequency transmission system based on the metering mode of the standard time and frequency terminal. The gating module is used to automatically select the direct channel of the optical splitter based on the topology of the time-frequency transmission system, and to achieve automatic online metering of each standard time-frequency terminal. The transmission module is used to select the direct channel of the optical splitter and enter the time synchronization mode of the standard time and frequency terminal. It combines the standard IRIG-B code and the designed uplink code to perform bidirectional time signal transmission and realize nanosecond-level time deviation measurement.

[0037] In this embodiment, the method for identifying the topological relationships of a time-frequency transfer system based on a metering pattern includes: The time tester transmits IRIG-B code timing signals through fiber optic links and optical splitters. The standard time and frequency terminal receives the IRIG-B code timing signals, performs time synchronization, and uploads the status, timing signals, and optical splitter channel number information to the first-layer optical splitter through the fiber optic loop. The time tester obtains the topology of the time and frequency transmission system from the first-layer optical splitter.

[0038] In this embodiment, after selecting the direct channel of the optical splitter, it enters the timing mode. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement. The process includes: The transmitted whole second T1 is modulated onto the IRIG-B code timing signal and sent to the standard time frequency transmission terminal; The standard time-frequency terminal under test parses the received IRIG-B code and records the time T2 of the definite timing edge Pr in the received IRIG-B code; The standard time and frequency terminal under test modulates the timestamp information of T2 onto the uplink code, and at the next whole second T3, modulates it onto the IRIG-B code timing signal and transmits it again. The timing tester receives and parses the uplink code, and records the time T4 of the uplink code's precise timing edge Pr; Based on times T1, T2, T3, and T4, calculate the link time deviation between the time tester and the standard time-frequency terminal under test.

[0039] In this embodiment, the method for calculating the link time deviation between the time tester and the standard time-frequency terminal under test based on times T1, T2, T3, and T4 includes: .

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An on-line metering method for a standard time-frequency terminal in an electric energy testing device, characterized in that, The method includes: Based on the metering mode of the standard time and frequency terminal, the topological relationship of the time and frequency transmission system is identified; Based on the topology of the time-frequency transmission system, the direct channel of the optical splitter is automatically selected to achieve automatic online metering of each standard time-frequency terminal; After selecting the direct channel of the optical splitter, it enters the time synchronization mode of the standard time and frequency terminal. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement.

2. The method of claim 1, wherein, Methods for identifying the topological relationships of time-frequency transfer systems based on metrological models include: The time tester transmits IRIG-B code timing signals through fiber optic links and optical splitters. The standard time and frequency terminal receives the IRIG-B code timing signals, performs time synchronization, and uploads the status, timing signals, and optical splitter channel number information to the first-layer optical splitter through the fiber optic loop. The time tester obtains the topology of the time and frequency transmission system from the first-layer optical splitter.

3. The method of claim 2, wherein, After selecting the direct-through channel of the optical splitter, it enters the timing mode. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement. The methods include: The transmitted whole second T1 is modulated onto the IRIG-B code timing signal and sent to the standard time frequency transmission terminal; The standard time-frequency terminal under test parses the received IRIG-B code and records the time T2 of the definite timing edge Pr in the received IRIG-B code; The standard time and frequency terminal under test modulates the timestamp information of T2 onto the uplink code, and at the next whole second T3, modulates it onto the IRIG-B code timing signal and transmits it again. The timing tester receives and parses the uplink code, and records the time T4 of the uplink code's precise timing edge Pr; Based on times T1, T2, T3, and T4, calculate the link time deviation between the time tester and the standard time-frequency terminal under test.

4. The method of claim 3, wherein, The method for calculating the link time deviation between the time tester and the standard time-frequency terminal under test based on times T1, T2, T3, and T4 includes: 。 5. An on-line metrology system for a standard time and frequency terminal in an electric energy testing installation, said system being used to implement the method according to any one of claims 1 to 4, characterized in that, The system includes: an identification module, a gating module, and a transmission module; The identification module is used to identify the topological relationship of the time and frequency transmission system based on the metering mode of the standard time and frequency terminal. The selection module is used to automatically select the direct channel of the optical splitter based on the topology of the time-frequency transmission system, and to achieve automatic online metering of each standard time-frequency terminal. The transmission module is used to select the direct channel of the optical splitter and enter the timing mode of the standard time and frequency terminal. It combines the standard IRIG-B code and the designed uplink code to perform bidirectional time signal transmission and realize nanosecond-level time deviation measurement.

6. The system of claim 5, wherein, Methods for identifying the topological relationships of time-frequency transfer systems based on metrological models include: The time tester transmits IRIG-B code timing signals through fiber optic links and optical splitters. The standard time and frequency terminal receives the IRIG-B code timing signals, performs time synchronization, and uploads the status, timing signals, and optical splitter channel number information to the first-layer optical splitter through the fiber optic loop. The time tester obtains the topology of the time and frequency transmission system from the first-layer optical splitter.

7. The system of claim 5, wherein, After selecting the direct channel of the optical splitter, it enters the time synchronization mode. Combining the standard IRIG-B code and the designed uplink code, it performs bidirectional time signal transmission to achieve nanosecond-level time deviation measurement. The process includes: The transmitted whole second T1 is modulated onto the IRIG-B code timing signal and sent to the standard time frequency transmission terminal; The standard time-frequency terminal under test parses the received IRIG-B code and records the time T2 of the definite timing edge Pr in the received IRIG-B code; The standard time and frequency terminal under test modulates the timestamp information of T2 onto the uplink code, and at the next whole second T3, modulates it onto the IRIG-B code timing signal and transmits it again. The timing tester receives and parses the uplink code, and records the time T4 of the uplink code's precise timing edge Pr; Based on times T1, T2, T3, and T4, calculate the link time deviation between the time tester and the standard time-frequency terminal under test.

8. The system of claim 7, wherein, The method for calculating the link time deviation between the time tester and the standard time-frequency terminal under test based on times T1, T2, T3, and T4 includes: 。

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