A multi-mode communication power distribution network substation quantum time-frequency synchronization method and system

Abstract

The application is suitable for the technical field of smart grid, and relates to a power distribution network area quantum time and frequency synchronization method and system based on multi-mode communication, and proposes a three-level architecture of "main reference quantum synchronization + concentrator quantum time keeping + terminal equipment multi-mode channel broadcast synchronization": the main reference unit realizes nanosecond-level synchronization with the area concentrator through quantum entanglement; the area concentrator is internally provided with a CPT atomic clock, and can keep time independently when the public network is interrupted; the area concentrator broadcasts a synchronization beacon frame through a communication network, and the terminal equipment realizes microsecond-level synchronization in combination with channel delay compensation. Through mechanisms such as area concentrator dual-computer redundancy, channel delay dynamic correction and terminal equipment independent time keeping, the application ensures the reliability and accuracy of synchronization, utilizes existing communication network infrastructure, supports the large-scale deployment of million-level electric meters, and provides a high-precision time reference for applications such as area topology identification and line loss analysis.

Description

Technical Field

[0001] This invention belongs to the field of smart grid technology, and in particular relates to a quantum time and frequency synchronization method and system for distribution network areas based on multi-mode communication. Background Technology

[0002] The distribution network area concentrator (also known as the area smart converged terminal) is the core equipment for data acquisition and management in the distribution area. It is responsible for collecting data from all terminal devices such as smart meters, photovoltaic inverters, and charging piles within the area and communicating with the main station system. The time synchronization accuracy of the concentrator directly affects the time base uniformity of the entire distribution area.

[0003] Currently, there are many problems with time synchronization in distribution network areas: Concentrators rely on public network time synchronization: Concentrators typically obtain NTP time through 4G / 5G public networks, where latency jitter can reach hundreds of milliseconds, resulting in time synchronization accuracy only at the second level. Furthermore, they completely lose their time reference in signal dead zones or when the network is interrupted. Smart meters have low synchronization accuracy: Concentrators broadcast time synchronization commands to meters through communication networks (including but not limited to fiber optics, PLC, RF, PLC+RF dual-mode, etc.), without considering channel propagation delay and communication network latency, often resulting in time synchronization errors at the second or even minute level. There is a lack of a unified high-precision reference: There is a lack of a unified, traceable, high-precision time reference between concentrators and terminal equipment (including but not limited to metering equipment, measuring equipment, control equipment, charging equipment, and distributed photovoltaic equipment) within the distribution area, making it impossible to support advanced applications such as distribution area topology identification (requiring microsecond-level synchronization) and line loss analysis (requiring millisecond-level synchronization). Concentrators themselves have insufficient timekeeping capabilities: Existing concentrators have limited timekeeping accuracy with built-in crystal oscillators (daily drift ±1~5 seconds), losing a usable time reference shortly after a public network interruption. Patent CN115102657B discloses a clock frequency synchronization method, apparatus, and storage medium for a metering device. The clock frequency synchronization method is applied between various metering devices within a substation area and includes: detecting the network status of the metering device and determining its network state, including online and offline states; determining the frequency control mode of the metering device based on the network state, wherein the frequency control mode is implemented through a pre-set frequency control module; calculating the time delay and time offset between the various metering devices, wherein each metering device is equipped with a frequency control module; and synchronizing the clock frequency of the various metering devices based on the time delay, time offset, and control mode. While this patent achieves clock frequency synchronization, it does not incorporate a quantum reference and concentrator timekeeping mechanism, resulting in lower time synchronization accuracy and exhibiting the same drawbacks as existing technologies.

[0004] Therefore, how to provide a method for obtaining high-precision time synchronization with a concentrator as the core timekeeping node and terminal devices through various communication networks is a problem that urgently needs to be solved by those in this technical field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication, in order to solve the problems in existing technologies such as distribution network area concentrators relying on public network time synchronization, low synchronization accuracy of terminal equipment (including but not limited to metering equipment, measuring equipment, control equipment, charging equipment, and distributed photovoltaic equipment), and lack of a unified high-precision benchmark; in addition, this invention also provides a quantum time-frequency synchronization system for distribution network areas based on multi-mode communication.

[0006] To solve the above-mentioned technical problems, the present invention also adopts the following technical solution:

[0007] In a first aspect, the present invention provides a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication, comprising the following steps:

[0008] S10. The main reference unit synchronizes with the concentrator in the first stage through quantum entanglement, so that the concentrator obtains a time reference synchronized with the main reference unit.

[0009] S20. The concentrator in the distribution area has a built-in CPT atomic clock that receives quantum entanglement synchronization signals and uses a PID algorithm to tame the local atomic clock, thereby establishing a high-precision time reference for the concentrator itself.

[0010] S30. The area concentrator monitors the public network connection status in real time. When the public network is detected to be normal, the area concentrator obtains an external time reference through the GNSS / 4G network and cross-calibrates with the CPT atomic clock. When the public network is interrupted or the satellite GNSS signal is interfered with, it automatically switches to the CPT atomic clock timekeeping mode to maintain high-precision time output.

[0011] S40. The area concentrator periodically broadcasts synchronization beacon frames to all terminal devices within the area through the communication module.

[0012] S50. The terminal device receives the synchronization beacon frame through the communication module, records the local reception time, extracts the broadcast timestamp, and calculates the time deviation between the local clock and the station concentrator by combining the channel propagation delay compensation.

[0013] S60. The terminal device adjusts the local RTC clock or crystal oscillator frequency according to the time deviation to achieve synchronization with the area concentrator, thereby indirectly obtaining a time reference synchronized with the main reference unit.

[0014] Furthermore, in S10, quantum entanglement synchronization adopts a round-trip protocol: the master reference unit generates entangled photon pairs and sends them to the area concentrator and the local detector respectively; the area concentrator records the photon arrival time through a single-photon detector, eliminates fiber optic transmission delay using the coincidence counting principle, and calculates the real-time clock difference with the master reference unit.

[0015] Furthermore, in S30, the timekeeping mode specifically means that the concentrator in the distribution area has a built-in CPT atomic clock and a temperature sensor, and maintains time accuracy based on a temperature-frequency compensation model.

[0016] Furthermore, in S40, the synchronization beacon frame includes a broadcast timestamp, broadcast sequence number, concentrator ID, timekeeping status flag, channel compensation coefficient, and broadcast period field.

[0017] Furthermore, in S50, the channel propagation delay compensation specifically includes:

[0018] Static compensation: The terminal device pre-stores a fixed processing delay of the communication module at the factory;

[0019] Dynamic compensation: The concentrator in the distribution area periodically performs bidirectional time exchange with terminal equipment at typical locations within the distribution area, measures the round-trip delay of the communication module in real time, calculates the one-way propagation delay, and notifies all terminal equipment through the channel compensation coefficient in the synchronization beacon frame;

[0020] Clustering compensation: Terminal devices within the transformer area are grouped according to the communication topology level, and meters in the same group share similar propagation delay compensation values.

[0021] Furthermore, it also includes a dual-redundancy mechanism for the zone concentrator: a primary concentrator and a backup concentrator are deployed within the zone, both of which are synchronized with the primary reference unit through quantum entanglement. When the primary concentrator fails, the backup concentrator automatically takes over the broadcasting task.

[0022] Furthermore, it also includes a terminal device autonomous timekeeping enhancement mechanism: the terminal device has a built-in temperature-compensated crystal oscillator and temperature sensor, and when it is unable to receive the wireless broadcast of the communication module, it maintains the local clock accuracy based on the temperature-frequency compensation model.

[0023] Furthermore, it also includes a broadcast cycle adaptive adjustment mechanism: the area concentrator dynamically adjusts the broadcast cycle based on the synchronization error statistics of the terminal equipment and the channel load of the communication network, and notifies the electricity meter through the synchronization beacon frame.

[0024] Furthermore, the terminal equipment includes metering equipment, measuring equipment, control equipment, charging equipment, and distributed photovoltaic equipment; the communication module includes optical fiber, PLC, RF, and PLC+RF dual-mode.

[0025] Secondly, the present invention also provides a quantum time-frequency synchronization system for distribution network areas based on multi-mode communication, comprising:

[0026] The main reference unit, deployed on the side of the distribution transformer in the distribution area or the upstream substation, includes a quantum entangled light source, a CPT atomic clock, a single-photon detector and an FPGA controller.

[0027] The distribution concentrator is deployed inside the distribution box of the distribution area. It contains a single-photon detector, a time-to-digital converter, a CPT atomic clock, a PLC wireless communication module, a PLC+RF wireless communication module, an RF wireless communication module, a 4G communication module, and an ARM / FPGA controller.

[0028] Multiple terminal devices are deployed on the user side within the distribution area, and each device contains an MCU, a temperature-compensated crystal oscillator, a temperature sensor, and an RTC module.

[0029] Compared with existing technologies, the quantum time-frequency synchronization method and system for distribution network areas provided by this invention have at least the following advantages:

[0030] In existing technologies, distribution network concentrators rely on public grid time synchronization, and the synchronization accuracy of terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) is low, lacking a unified high-precision reference. This invention addresses this by integrating a CPT atomic clock into the distribution network concentrator, synchronizing with the main reference through quantum entanglement. In the event of a public grid outage, the concentrator achieves autonomous timekeeping accuracy better than ±1μs / day, completely eliminating dependence on the public grid. Furthermore, this invention utilizes communication networks (including but not limited to fiber optics, PLC, RF, and PLC+RF dual-mode) for broadcast synchronization combined with channel delay compensation, achieving synchronization accuracy of terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) better than ±10μs, meeting advanced application requirements such as distribution network topology identification and line loss analysis. This invention deploys quantum synchronization devices (single-photon detectors, TDC, and CPT atomic clocks) only in the main reference unit and concentrator, allowing for seamless synchronization of a vast number of terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices). This invention requires only a communication module (PLC, PLC+RF, RF wireless) and a low-cost crystal oscillator for metering equipment, control equipment, charging equipment, and distributed photovoltaic equipment, resulting in low deployment costs. Through multiple mechanisms, including dual-machine redundancy of the distribution area concentrator, dynamic channel delay compensation, and autonomous timekeeping of terminal equipment (including but not limited to metering equipment, measurement equipment, control equipment, charging equipment, and distributed photovoltaic equipment), this invention ensures the continuous availability of the synchronization system during equipment failures or channel fluctuations, guaranteeing synchronization reliability and accuracy. Furthermore, this invention is based on existing communication network protocols (including but not limited to fiber optic, PLC, RF, PLC+RF dual-mode, etc.), fully utilizing the existing power line carrier communication infrastructure deployed in the distribution area, eliminating the need for additional cabling and resulting in lower costs. Attached Figure Description

[0031] To more clearly illustrate the solution of the present invention, a brief introduction will be given to the drawings used in the description of the embodiments below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 A flowchart of a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication provided in this embodiment of the invention;

[0033] Figure 2 This is a schematic diagram of the synchronization beacon frame format in a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication, provided in an embodiment of the present invention.

[0034] Figure 3 This invention provides a flowchart of the dual-mode timekeeping state switching of the distribution area concentrator in a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication, as provided in an embodiment of the invention.

[0035] Figure 4 A flowchart of the terminal equipment synchronization process in a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication provided in this embodiment of the invention;

[0036] Figure 5 A timing diagram for online channel propagation delay correction in a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication, provided in an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of the system architecture for a quantum time-frequency synchronization system of a distribution network area based on multi-mode communication, including quantum timekeeping of the distribution network area concentrator, terminal equipment, and communication network, is provided for an embodiment of the present invention.

[0038] Figure 7 A block diagram of the internal structure of a distribution network concentrator in a multi-mode communication distribution network quantum time-frequency synchronization system is provided for an embodiment of the present invention.

[0039] Figure 8 This is a block diagram of the internal structure of a terminal device in a quantum time-frequency synchronization system for a distribution network area based on multi-mode communication, provided as an embodiment of the present invention. Detailed Implementation

[0040] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0042] This invention provides a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication. It is applied to scenarios where distribution network concentrators serve as core timekeeping nodes, and a massive number of terminal devices (including but not limited to metering devices, measurement devices, control devices, charging devices, and distributed photovoltaic devices) obtain high-precision time synchronization through communication networks (including but not limited to optical fiber, PLC, RF, and PLC+RF dual-mode, etc.). The quantum time-frequency synchronization method for distribution network areas includes the following steps:

[0043] S10. The main reference unit achieves primary synchronization with the local concentrator through quantum entanglement, enabling the local concentrator to obtain a time reference synchronized with the main reference unit. S20. The local concentrator's built-in CPT atomic clock receives the quantum entanglement synchronization signal and uses a PID algorithm to tame the local atomic clock, establishing its own high-precision time reference. S30. The local concentrator monitors the public network connection status in real time. When the public network is detected to be normal, the local concentrator obtains an external time reference through the GNSS / 4G network and performs mutual calibration with the CPT atomic clock. When the public network is interrupted or the satellite GNSS signal is interfered with... The system automatically switches to CPT atomic clock timekeeping mode to maintain high-precision time output during disturbances. In S40, the station concentrator periodically broadcasts synchronization beacon frames to all terminal devices within the station area via the communication module. In S50, the terminal devices receive the synchronization beacon frames via the communication module, record the local reception time, extract the broadcast timestamp, and calculate the time deviation between the local clock and the station concentrator by combining channel propagation delay compensation. In S60, the terminal devices adjust the local RTC clock or crystal oscillator frequency according to the time deviation to achieve synchronization with the station concentrator, thereby indirectly obtaining a time reference synchronized with the main reference unit.

[0044] This invention ensures synchronization reliability and accuracy through mechanisms such as dual-machine redundancy of the transformer area concentrator, dynamic channel delay correction, and autonomous timekeeping of terminal equipment. It utilizes existing communication network infrastructure to support large-scale deployment of millions of meters and provides a high-precision time reference for applications such as transformer area topology identification and line loss analysis.

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0046] This invention provides a quantum time-frequency synchronization method for distribution network areas based on multi-mode communication. It is applied to scenarios where distribution network concentrators serve as core timekeeping nodes, and a massive number of terminal devices (including but not limited to metering devices, measurement devices, control devices, charging devices, and distributed photovoltaic devices) obtain high-precision time synchronization through communication networks (including but not limited to optical fiber, PLC, RF, and PLC+RF dual-mode, etc.). Figures 1 to 5 In this embodiment, the quantum time-frequency synchronization method for distribution network areas includes the following steps:

[0047] S10. The main reference unit achieves primary synchronization with the concentrator through quantum entanglement, enabling the concentrator to obtain a time reference synchronized with the main reference unit.

[0048] Specifically, in this embodiment, the quantum entanglement synchronization in step S10 adopts a round-trip protocol: the master reference unit generates entangled photon pairs and sends them to the area concentrator and the local detector respectively; the area concentrator records the photon arrival time through a single-photon detector, eliminates fiber optic transmission delay using the coincidence counting principle, and calculates the real-time clock difference with the master reference; the concentrator disciplines the local CPT atomic clock according to the clock difference, and the synchronization accuracy is better than 1 ns.

[0049] S20: The concentrator has a built-in CPT atomic clock that receives quantum entanglement synchronization signals and uses a PID algorithm to tame the local atomic clock, thus establishing a high-precision time reference for the concentrator itself.

[0050] S30: The local area concentrator monitors the public network connection status in real time. When the public network is detected to be normal, the local area concentrator obtains an external time reference through the GNSS / 4G network and cross-calibrates with the CPT atomic clock. When the public network is interrupted or the satellite GNSS signal is interfered with, it automatically switches to the CPT atomic clock timekeeping mode to maintain high-precision time output.

[0051] Specifically, in this embodiment, the autonomous timekeeping mode of the concentrator in step S30 includes: the concentrator of the distribution area has a built-in CPT atomic clock (frequency stability better than 5×10^-11 / s) and a temperature sensor. During the public network interruption, the concentrator of the distribution area maintains the time accuracy based on the temperature-frequency compensation model. The timekeeping accuracy is better than ±1μs / day, which can support the continuous operation of the distribution area for more than 30 days without external time synchronization.

[0052] S40, the distribution area concentrator periodically broadcasts synchronization beacon frames to all terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) within the distribution area through communication modules (including but not limited to optical fiber, PLC, RF, PLC+RF dual-mode, etc.).

[0053] Specifically, in this embodiment, the synchronization beacon frame of the communication module (including but not limited to optical fiber, PLC, RF, PLC+RF dual-mode, etc.) in step S40 includes:

[0054] Preamble (8 bytes): Fixed mode, used for frame synchronization;

[0055] Frame control (16 bytes): Standard PLC frame control field;

[0056] Broadcast type (1 byte): 0x0F = Quantum Synchronous Broadcast;

[0057] Broadcast timestamp (4 bytes): Based on the 1PPS count of the concentrator CPT atomic clock, accurately characterizing the beacon frame transmission time;

[0058] Broadcast sequence number (2 bytes): Incrementing count, used for replay protection and packet loss detection;

[0059] Concentrator ID (2 bytes): Identifies the broadcast source (primary / backup concentrator);

[0060] Timekeeping status flag (1 byte): 0x01 = Public network timekeeping mode, 0x02 = Quantum timekeeping mode;

[0061] Channel compensation coefficient (1 byte): Used to notify the meter of the current estimated channel delay;

[0062] Timekeeping status flag (1 byte): Indicates whether the concentrator is currently in public network timekeeping mode or quantum timekeeping mode;

[0063] Broadcast period (1 byte): The interval between the next broadcast (1 to 10 seconds);

[0064] Reserved field (4 bytes): Used for future expansion;

[0065] CRC check (4 bytes): Used for frame check sequence.

[0066] Before sending beacon frames, the concentrator aligns the 1PPS pulse edge of the CPT atomic clock with the start delimiter of the beacon frame to ensure accurate timestamps.

[0067] S50: The terminal device receives the synchronization beacon frame through the communication module, records the local reception time, extracts the broadcast timestamp, and calculates the time deviation between the local clock and the station concentrator by combining the channel propagation delay compensation.

[0068] Specifically, in this embodiment, the channel propagation delay compensation in step S50 adopts a hybrid approach:

[0069] Static compensation: The terminal equipment (including but not limited to metering equipment, measuring equipment, control equipment, charging equipment, distributed photovoltaic equipment) has a fixed processing delay pre-stored in the communication module (including but not limited to fiber optic, PLC, RF, PLC+RF dual-mode, etc.) at the factory;

[0070] Dynamic compensation: The concentrator in the distribution area periodically (e.g., every hour) exchanges bidirectional time with terminal equipment at typical locations within the distribution area (including but not limited to metering equipment, measuring equipment, control equipment, charging equipment, and distributed photovoltaic equipment), measures the round-trip delay of the communication module (including but not limited to fiber optic, PLC, RF, PLC+RF dual-mode, etc.) in real time, calculates the one-way propagation delay, and notifies all terminal equipment (meters / inverters / charging piles) through the channel compensation coefficient in the broadcast beacon frame.

[0071] Clustering compensation: Terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) within the transformer area are grouped according to the communication (including but not limited to fiber optic, PLC, RF, PLC+RF dual-mode, etc.) topology level, and meters in the same group share similar propagation delay compensation values.

[0072] S60: The terminal equipment adjusts the local RTC clock or crystal oscillator frequency according to the time deviation to achieve synchronization with the area concentrator, thereby indirectly obtaining a time reference synchronized with the main reference unit.

[0073] Furthermore, this embodiment also includes a two-way time exchange correction mechanism between the distribution area concentrator and the smart meter: the distribution area concentrator periodically selects representative meters for precise time synchronization, accurately calculates the one-way delay by measuring the round-trip delay, and corrects the timestamp or compensation parameters of the broadcast beacon frame accordingly.

[0074] Furthermore, this embodiment also includes a multi-concentrator redundancy mechanism: two concentrators, a primary and a backup, are deployed within the distribution area. Both are synchronized with the primary reference unit through quantum entanglement. The primary concentrator is responsible for broadcasting synchronization beacon frames, while the backup concentrator is in hot standby mode, continuously receiving broadcasts from the primary concentrator and maintaining its own clock synchronization. When the primary concentrator fails (no response for 10 consecutive broadcast cycles), the backup concentrator automatically takes over the broadcasting task and begins broadcasting synchronization beacon frames (using its own concentrator ID). Terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) simultaneously listen to the broadcasts of both concentrators, select the synchronization source based on the timekeeping status flag and reception quality, and predict time deviations using historical synchronization data during switching to achieve a seamless transition.

[0075] Furthermore, this embodiment also includes an autonomous timekeeping enhancement mechanism for terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices): the terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) have built-in temperature-compensated crystal oscillators and temperature sensors, and when they cannot receive PLC, PLC+RF, or RF wireless broadcasts (such as excessive power line noise or concentrator maintenance), they maintain local clock accuracy based on a temperature-frequency compensation model.

[0076] Furthermore, this embodiment also includes adaptive adjustment of the broadcast period: the distribution area concentrator dynamically adjusts the broadcast period based on the synchronization error statistics of terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) and the channel load of communication networks (including but not limited to optical fiber, PLC, RF, and PLC+RF dual-mode), and notifies the electricity meter through beacon frames.

[0077] Specifically, in this embodiment, the concentrator dynamically adjusts the broadcast period based on the meter synchronization error statistics and the PLC channel load. When the average synchronization error reported by the meter exceeds 10μs, the broadcast period is shortened (e.g., from 5 seconds to 2 seconds); when the error is less than 5μs and the channel load exceeds 70%, the broadcast period is extended (e.g., increased to 10 seconds). The broadcast period is communicated to the meter via beacon frames, and the meter adjusts its monitoring window accordingly.

[0078] This invention also provides a quantum time-frequency synchronization system for distribution network areas based on multi-mode communication, employing the quantum time-frequency synchronization method for distribution network areas based on multi-mode communication described in the above embodiments, combined with... Figures 6 to 7 In this embodiment, the quantum time-frequency synchronization system for distribution network areas based on multi-mode communication includes:

[0079] The main reference unit, deployed on the side of the distribution transformer in the distribution area or the upstream substation, includes a quantum entangled light source, a CPT atomic clock, a single-photon detector and an FPGA controller.

[0080] The distribution area concentrator, deployed in the distribution box, includes a single-photon detector, a time-to-digital converter, a CPT atomic clock, a PLC wireless communication module, a PLC+RF wireless communication module, an RF wireless communication module, a 4G communication module, and an ARM / FPGA controller.

[0081] Multiple terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) are deployed on the user side within the distribution area, including MCUs, temperature-compensated crystal oscillators, temperature sensors, and RTC modules.

[0082] Specifically, in this embodiment, a single-photon detector is used to receive entangled photon pairs from the main reference unit; a time-to-digital converter is connected to the single-photon detector and is used to convert the photon arrival time into a digital signal; a CPT atomic clock is used to generate a local high-precision time reference and autonomously maintain time when the public network is interrupted; a communication module (including but not limited to fiber optic, PLC, RF, and PLC+RF dual-mode) is used to broadcast synchronization beacon frames to multiple terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices); a 4G communication module is used to acquire the public network time reference; and an ARM / FPGA controller is connected to the time-to-digital converter. The device connects to a converter, a CPT atomic clock, communication modules (including but not limited to fiber optic, PLC, RF, and PLC+RF dual-mode) and a 4G module. It is used to calculate the quantum clock difference with the main reference unit based on the photon arrival time, tame the CPT atomic clock, monitor the public network connection status in real time, automatically switch between time synchronization mode and timekeeping mode, generate synchronization beacon frames, control the periodic broadcasting of communication modules (including but not limited to fiber optic, PLC, RF, and PLC+RF dual-mode), and optionally perform bidirectional time exchange with terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices) to measure channel propagation delay.

[0083] Example 1

[0084] Standard distribution area concentrator quantum timekeeping and meter PLC synchronization system

[0085] like Figure 6 As shown, this embodiment provides a quantum time-frequency synchronization system for a distribution network area, including:

[0086] The main reference unit, deployed on the side of the distribution transformer in the distribution area or the upstream substation, includes a quantum entangled light source (based on PPKTP crystal, with a brightness of 10^6 pairs / second), a CPT atomic clock, a single-photon detector, and an ARM / FPGA controller.

[0087] The distribution area concentrator, deployed in the distribution box, includes a single-photon detector, a time-to-digital converter (TDC, resolution 10ps), a CPT atomic clock (frequency stability better than 5×10^-11 / s), a PLC communication module, a 4G communication module, and an ARM / FPGA controller.

[0088] The smart meters consist of 1,000 single-phase smart meters in the distribution area. Each meter includes a PLC communication module, MCU, temperature-compensated crystal oscillator (TCXO, ±10ppm), temperature sensor, and RTC module.

[0089] Concentrator-level quantum synchronization and timekeeping: The concentrator achieves primary synchronization with the master reference unit via a quantum entangled fiber optic link. The master reference unit generates entangled photon pairs, which are transmitted to the concentrator and the local detector via fiber optic cables. The concentrator records the photon arrival time t. C Master reference record t M , t delay Given the known fixed delay within the primary reference unit or the fiber optic link, the clock difference Δτ = t is calculated using coincidence counting. C – t M – t delay The concentrator ARM / FPGA uses a PID algorithm based on Δτ to tame the local CPT atomic clock, synchronizing the concentrator clock with the main reference unit with a synchronization accuracy better than 1ns.

[0090] The concentrator monitors the 4G public network connection status in real time. For example... Figure 3 As shown, when the public network is normal, the concentrator receives time via GNSS through the satellite receiver module, cross-calibrates with the CPT atomic clock, and reports the synchronization status to the master station. When interference with the GNSS signal is detected, the concentrator automatically switches to quantum timekeeping mode, relying on the CPT atomic clock to maintain time output. Under temperature compensation, the CPT atomic clock has a timekeeping accuracy better than ±1μs / day and can support continuous operation of the station area for more than 30 days.

[0091] Smart meter synchronization process: The smart meter synchronization process is as follows:

[0092] When the electricity meter is powered on, the PLC module initializes and enters monitoring mode.

[0093] Upon receiving a synchronization beacon frame, record the local reception time. (Based on TCXO clock) Parsing broadcast timestamps 1. Timekeeping status flag; 2. Channel compensation coefficient;

[0094] Read the factory-pre-stored fixed processing delay from the meter's non-volatile memory. ;

[0095] The dynamic propagation delay is obtained based on the channel compensation coefficient. (Measured and broadcast periodically by a concentrator);

[0096] Calculate time deviation ;

[0097] Select the adjustment mode based on the magnitude of the deviation:

[0098] like Coarse adjustment mode is used: the RTC register is set directly;

[0099] like The fine-tuning mode is adopted: the frequency adjustment amount is calculated and gradually corrected at a slope of no more than 1 second per minute;

[0100] Update the local time of the electricity meter and output a synchronized 1PPS signal;

[0101] Waiting for the next broadcast cycle.

[0102] Example 2

[0103] Online dynamic correction of channel propagation delay

[0104] This embodiment, based on embodiment 1, adds a two-way time exchange mechanism between the concentrator and the electricity meter. For example... Figure 5 As shown, the concentrator performs precise time synchronization with 3-5 representative meters (selected according to topology level) within the distribution area every hour:

[0105] The concentrator sends a request frame to meter i and records the sending time T1.

[0106] When meter i receives a request frame, it records the reception time T2, and then sends a response frame, recording the sending time T3.

[0107] The concentrator receives the response frame and records the reception time T4.

[0108] Calculate the round-trip delay RTT = (T4 - T1) - (T3 - T2), and the one-way delay τ_i = RTT / 2;

[0109] The concentrator performs statistical analysis on the τ_i measured by each meter to obtain the average propagation delay τ_avg of the PLC channel in the current distribution area. After quantification by the "channel compensation coefficient" field in the broadcast beacon frame, it notifies all meters.

[0110] This method can effectively compensate for channel delay fluctuations caused by temperature and load changes, and control the meter synchronization error within ±5μs.

[0111] Example 3

[0112] Electricity meter autonomous timekeeping enhancement

[0113] This embodiment addresses scenarios where the electricity meter is temporarily unable to receive PLC broadcasts (e.g., excessive power line noise or concentrator maintenance). The meter incorporates a built-in TCXO crystal oscillator and a temperature sensor. After the last successful synchronization, the temperature value is read every 10 minutes, and a temperature-frequency compensation coefficient is obtained from a table to estimate the time drift.

[0114]

[0115] This is the estimated cumulative time drift since the last successful synchronization. This refers to the relative deviation of the crystal oscillator frequency caused by temperature. This is due to the relative deviation of the crystal oscillator frequency caused by aging.

[0116] The meter output time T_local = T_last + ∆T_est + local counter. Experiments show that during a 24-hour communication interruption, the time error can be controlled within ±0.5 seconds, meeting basic functions such as power outage event reporting.

[0117] The above-described multi-mode communication distribution network quantum time and frequency synchronization method and system, compared with existing technologies, addresses the shortcomings of existing technologies. Existing technologies rely on public network time synchronization for distribution network concentrators, have low synchronization accuracy for terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices), and lack a unified high-precision reference. The concentrator of this invention incorporates a CPT atomic clock, synchronizing with the main reference through quantum entanglement. In the event of a public network outage, its autonomous timekeeping accuracy is better than ±1μs / day, completely eliminating dependence on the public network. Furthermore, this invention utilizes communication networks (including but not limited to fiber optics, PLC, RF, PLC+RF dual-mode, etc.) for broadcast synchronization combined with channel delay compensation, achieving a synchronization accuracy of better than ±10μs for terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices), meeting advanced application requirements such as distribution network topology identification and line loss analysis. This invention deploys quantum synchronization devices (single-photon detectors, TDC, CPT atomic clocks) only in the main reference unit and concentrator, allowing for seamless synchronization of a massive number of terminal devices (including but not limited to metering devices, measuring devices, control devices, charging devices, and distributed photovoltaic devices). This invention requires only a communication module (PLC, PLC+RF, RF wireless) and a low-cost crystal oscillator for metering equipment, control equipment, charging equipment, and distributed photovoltaic equipment, resulting in low deployment costs. Through multiple mechanisms, including dual-machine redundancy of the distribution area concentrator, dynamic channel delay compensation, and autonomous timekeeping of terminal equipment (including but not limited to metering equipment, measurement equipment, control equipment, charging equipment, and distributed photovoltaic equipment), this invention ensures the continuous availability of the synchronization system during equipment failures or channel fluctuations, guaranteeing synchronization reliability and accuracy. Furthermore, this invention is based on existing communication network protocols (including but not limited to fiber optic, PLC, RF, PLC+RF dual-mode, etc.), fully utilizing the existing power line carrier communication infrastructure deployed in the distribution area, eliminating the need for additional cabling and resulting in lower costs.

[0118] Obviously, the embodiments described above are merely preferred embodiments of the present invention, and not all embodiments. The accompanying drawings illustrate preferred embodiments of the present invention, but do not limit the scope of the patent. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this invention.

Claims

1. A quantum time-frequency synchronization method for a multi-mode communication power distribution network substation, characterized in that, Includes the following steps: S10. The main reference unit synchronizes with the concentrator in the first stage through quantum entanglement, so that the concentrator obtains a time reference synchronized with the main reference unit. In S10, quantum entanglement synchronization adopts a round-trip protocol: the main reference unit generates entangled photon pairs, which are sent to the concentrator and the local detector, respectively. The area concentrator records the photon arrival time through a single-photon detector, uses the coincidence counting principle to offset the fiber optic transmission delay, and calculates the real-time clock difference with the main reference unit. S20. The concentrator in the distribution area has a built-in CPT atomic clock that receives quantum entanglement synchronization signals and uses a PID algorithm to tame the local atomic clock, thereby establishing a high-precision time reference for the concentrator itself. S30. The area concentrator monitors the public network connection status in real time. When the public network is detected to be normal, the area concentrator obtains an external time reference and cross-calibrates with the CPT atomic clock. When the public network is interrupted or the signal is interfered with, it automatically switches to the CPT atomic clock timekeeping mode to maintain high-precision time output. In S30, the timekeeping mode is specifically as follows: the concentrator of the distribution area is equipped with a CPT atomic clock and a temperature sensor, and maintains time accuracy based on a temperature-frequency compensation model; S40. The area concentrator periodically broadcasts synchronization beacon frames to all terminal devices within the area through the communication module. S50. The terminal device receives the synchronization beacon frame through the communication module, records the local reception time, extracts the broadcast timestamp, and calculates the time deviation between the local clock and the station concentrator by combining the channel propagation delay compensation. In S50, channel propagation delay compensation specifically includes: Static compensation: The terminal device pre-stores a fixed processing delay of the communication module at the factory; Dynamic compensation: The concentrator in the distribution area periodically exchanges two-way time with the terminal equipment in the distribution area, measures the round-trip delay of the communication module in real time, calculates the one-way propagation delay, and notifies all terminal equipment through the channel compensation coefficient in the synchronization beacon frame; Clustering compensation: Terminal devices within the transformer area are grouped according to the communication topology hierarchy, and meters in the same group share similar propagation delay compensation values; S60. The terminal device adjusts the local RTC clock or crystal oscillator frequency according to the time deviation to achieve synchronization with the area concentrator, thereby indirectly obtaining a time reference synchronized with the main reference unit.

2. The quantum time-frequency synchronization method for multi-mode communication power distribution network area according to claim 1, characterized in that, In step S40, the synchronization beacon frame includes a broadcast timestamp, broadcast sequence number, concentrator ID, timekeeping status flag, channel compensation coefficient, and broadcast period field.

3. The quantum time-frequency synchronization method for multi-mode communication power distribution network area according to claim 1, characterized in that, It also includes a dual-redundancy mechanism for the zone concentrator: a main concentrator and a backup concentrator are deployed in the zone, both of which are synchronized with the main reference unit through quantum entanglement. When the main concentrator fails, the backup concentrator automatically takes over the broadcasting task.

4. The quantum time-frequency synchronization method for multi-mode communication power distribution network area according to claim 3, characterized in that, It also includes a terminal device autonomous timekeeping enhancement mechanism: the terminal device has a built-in temperature-compensated crystal oscillator and temperature sensor, and maintains local clock accuracy based on a temperature-frequency compensation model when it is unable to receive the wireless broadcast of the communication module.

5. A quantum time-frequency synchronization method for distribution network areas based on multi-mode communication according to claim 4, characterized in that, It also includes a broadcast cycle adaptive adjustment mechanism: the area concentrator dynamically adjusts the broadcast cycle based on the synchronization error statistics of the terminal equipment and the channel load of the communication network, and notifies the electricity meter through the synchronization beacon frame.

6. The quantum time-frequency synchronization method for multi-mode communication power distribution network area according to claim 1, characterized in that, The terminal equipment includes metering equipment, measuring equipment, control equipment, charging equipment, and distributed photovoltaic equipment; the communication module includes optical fiber, PLC, RF, and PLC+RF dual-mode.

7. A system employing the method according to any one of claims 1 to 6, characterized in that include: The main reference unit, deployed on the side of the distribution transformer in the distribution area or the upstream substation, includes a quantum entangled light source, a CPT atomic clock, a single-photon detector and an FPGA controller. The distribution concentrator is deployed inside the distribution box of the distribution area and contains a single-photon detector, a time-to-digital converter, a CPT atomic clock, a communication module, and an ARM / FPGA controller. Multiple terminal devices are deployed on the user side within the distribution area, and each device contains an MCU and an RTC module.

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