CN112272360B - Current differential protection data synchronization method and system based on 5G network time synchronization - Google Patents

本发明公开了一种基于5G网络对时的电流差动保护数据同步方法及系统，方法包括以下步骤：电流差动保护装置的5G模块接收5G基站的广播消息SIB9和定时提前量；根据自身所处状态和定时提前量计算广播消息的传播时延τ；基于广播消息SIB9和传播时延τ对电流差动保护装置本地时钟进行修正；以修正后的本地时钟为基准，5G模块为电流差动保护装置提供电流差动保护数据同步采样所需的时间信息和绝对时间标签。本发明利用5G模块接收来自基站的时间相关量设计一种实现时间同步的技术方案，该方案通过补偿传播时延，实现基站对5G模块的授时功能；并以此为基础，为电流差动保护装置提供同步采样的对时信号，实现采样数据的同步。

The invention discloses a current differential protection data synchronization method and system based on 5G network time synchronization. The method includes the following steps: a 5G module of a current differential protection device receives a broadcast message SIB9 and a timing advance of a 5G base station; The propagation delay τ of the broadcast message is calculated based on the state and timing advance; the local clock of the current differential protection device is corrected based on the broadcast message SIB9 and the propagation delay τ; based on the corrected local clock, the 5G module is a current differential protection device. The protection device provides the time information and absolute time stamp required for synchronous sampling of current differential protection data. The present invention uses the 5G module to receive the time correlation quantity from the base station to design a technical scheme for realizing time synchronization. The scheme realizes the timing function of the base station to the 5G module by compensating the propagation delay; and based on this, the current differential protection is The device provides a time synchronization signal for synchronous sampling to realize the synchronization of sampling data.

Current differential protection data synchronization method and system based on 5G network time synchronization

Technical Field

The invention relates to a current differential protection data synchronization method and system based on 5G network time synchronization, and belongs to the technical field of relay protection of power systems.

Background

The emergence and rapid development of the 5G communication technology provide an economic and reliable communication means for the power grid. Meanwhile, the 5G network communication process contains time information, and 300ns time synchronization error can be realized between 5G base stations at present. The method can be used as a value-added service to provide time service function for other industries.

The synchronous sampling of the current differential protection data means that two sides of a line are guaranteed to be sampled at the same time. At present, there are two main types of current differential protection data synchronization methods, one is a ping-pong synchronization method based on a data channel, and the other is a synchronization method based on satellite time service. The former is based on the consistent time delay of the channel back and forth path, calculates the path transmission time delay and the clock deviation of two sides, and adjusts the sampling data of two sides or the clocks of two sides to complete the data synchronization process. The method has strict requirements on channel delay jitter, data interaction is generally carried out by adopting optical fibers, and data synchronization cannot be realized through the method due to inconsistent round-trip routing delay in 5G communication. The synchronization method based on satellite time service depends on GPS/Beidou time service signals, and the current values on two sides are synchronously sampled by using pulse per second (1PPS) signals and serial port time information output by a satellite receiving module. This method requires each differential protection device to be equipped with a satellite receiving module, which greatly increases the economic cost; on the other hand, satellite signals are susceptible to interference, affecting the reliability of synchronization.

Therefore, the conventional data synchronization method cannot be completely adapted to 5G communication current differential protection.

Disclosure of Invention

Aiming at the defects of the method, the invention provides a current differential protection data synchronization method and system based on 5G network time synchronization, which can provide high-precision time information for a differential protection device and reasonably utilize the high-precision time information to realize synchronous sampling of protection devices on two sides of a line.

The technical scheme adopted for solving the technical problems is as follows:

on one hand, the current differential protection data synchronization method based on 5G network time synchronization provided by the embodiment of the present invention includes the following steps:

a 5G module of the current differential protection device receives a broadcast message SIB9 of a 5G base station and a timing advance;

calculating the propagation delay tau of the broadcast message according to the state of the broadcast message and the timing advance;

modifying the local clock of the current differential protection device based on the broadcast message SIB9 and the propagation delay tau;

and taking the corrected local clock as a reference, and providing time information and an absolute time tag required by synchronous sampling of current differential protection data for the current differential protection device by the 5G module.

The SIB is a 5G NR system information block through which the 5G module can acquire basic information on the base station side, for example, the SIB9 contains information related to GPS time and coordinated universal time. The system message block can be acquired at the 5G module through periodic broadcast or user side request. The TA value is a propagation delay estimation performed by the 5G communication to ensure that signals located in the same subframe but in different frequency domain resources can reach the base station at the same time, and is a necessary condition for ensuring that the 5G communication itself does not generate interference. The base station determines the distance between the uplink signal and the position of the base station through detection, acquires a TA value, and feeds the TA value back to the 5G module through downlink information. The invention designs the time service mode from the base station to the 5G module by utilizing the two time correlation quantities.

As a possible implementation manner of this embodiment, calculating the propagation delay τ of the broadcast message according to the state of the broadcast message and the timing advance includes:

judging the state of the module, and when the 5G module is initialized, the calculation formula of the propagation delay is as follows:

τ₁＝(TA×T_μ)/2

when the 5G module is in a connection state, the propagation delay calculation formula is as follows:

τ₂＝[N_TA,old+(TA-31)×T_μ]/2

in the formula, TA is timing advance, and when the 5G module is in an initialized state, the TA index value is 0-3846; in the 5G module connection state, the TA index value is 0-63. T is_μGranularity of timing advance TA, T_μ＝16*64*T_C/2^μ，T_CIs the minimum time unit of 5G NR,. mu.0, 1,2 …, N_TA,oldAnd the actual adjustment value of the timing advance TA of the 5G module in the previous time.

As a possible implementation manner of this embodiment, modifying the local clock of the current differential protection device based on the broadcast message SIB9 and the propagation delay τ includes:

calculating the clock deviation between the base station side and the local clock;

and correcting the local clock according to the deviation between the base station side and the local clock.

The GPS time and the coordinated universal time in the broadcast message SIB9 record the time information t of the base station sending SIB9 broadcast message₁With base station side clocksThe standard is.

As a possible implementation manner of this embodiment, a calculation formula of the clock deviation Δ t between the base station side and the local clock is as follows:

Δt＝t₁-t₂-τ

wherein, tau is the propagation delay of the broadcast message, including the propagation delay tau₁Or propagation delay tau₂。

On the other hand, the current differential protection data synchronization system based on 5G network time synchronization provided by the embodiment of the invention comprises a 5G module, a clock module, a synchronous sampling control module, a data acquisition module and a CPU processor;

the 5G module acquires and decodes a broadcast message SIB9 and a timing advance TA from a 5G base station and marks a time stamp t on the receiving time of the broadcast message SIB9₂；

The 5G module simultaneously performs data interaction with the opposite end of the line;

the clock module is used for correcting the local clock based on the time correlation quantity analyzed by the 5G module and outputting a time tick signal;

the synchronous sampling control module is used for receiving the high-precision time information of the clock module and outputting sampling pulses meeting requirements;

the data acquisition module is used for converting the acquired current differential protection data analog quantity into a corresponding digital quantity;

and the CPU processor sets absolute time labels for the data packets, analyzes and processes the local data and the end data, and performs relay protection measurement, logic and control.

As a possible implementation manner of this embodiment, the clock module includes a local clock, a data storage unit, a time synchronization unit, and an output unit; the data storage unit stores the time correlation quantity analyzed by the 5G module; the time synchronization unit calculates the propagation delay tau of the broadcast message according to the time advance TA and calculates the clock difference between the base station side and the 5G module, the clock module corrects the local clock according to the clock difference, and the output unit outputs the time setting signal.

As a possible implementation manner of this embodiment, the calculation formula of the time deviation Δ t is:

Δt＝t₁-t₂-τ

As a possible implementation manner of this embodiment, the propagation delay of the broadcast message includes:

when the 5G module is initialized, the propagation delay is:

τ₁＝(TA×T_μ)/2

when the 5G module is in the connected state, the propagation delay is:

τ₂＝[N_TA,old+(TA-31)×T_μ]/2

in the formula, TA is timing advance, and when the 5G module is in an initialized state, the TA index value is 0-3846; in the 5G module connection state, the TA index value is 0-63. T is_μGranularity of timing advance TA, T_μ＝16*64*T_C/2^μ，T_CIs the minimum time unit of 5G NR,. mu.0, 1,2 …, N_TA,oldAnd the actual adjustment value of the timing advance TA of the 5G module in the previous time.

As a possible implementation manner of this embodiment, the clock module supports an external input time synchronization manner.

The technical scheme of the embodiment of the invention has the following beneficial effects:

the invention utilizes the 5G module to receive the time correlation quantity from the base station; designing a technical scheme for realizing time synchronization by using time correlation quantity, wherein the scheme realizes the time service function of the base station to the 5G module by compensating propagation delay; and on the basis, a synchronous sampling time tick signal is provided for the current differential protection device, so that the synchronization of sampling data is realized.

The 5G network is used as a current differential protection data interaction channel, and meanwhile, high-precision time information contained in the 5G network provides a time reference for synchronization of differential protection data. Compared with the traditional ping-pong algorithm and the satellite time service method, the method does not need to lay an optical fiber line or install a satellite receiving module, is convenient to use and has lower cost.

The invention utilizes the time signal of 5G network communication: a specific 5G wireless time service mode is designed by a system message block SIB9 and a time advance TA, and the method does not need extra signaling overhead at a base station side and is simple to implement.

Description of the drawings:

FIG. 1 is a flow diagram illustrating a method for current differential protection data synchronization over 5G network pairs in accordance with an exemplary embodiment;

FIG. 2 is a schematic diagram illustrating a 5G network time flow according to an example embodiment;

FIG. 3 is a schematic diagram illustrating a 5G module acquiring time signals in accordance with an exemplary embodiment;

FIG. 4 is a flow chart illustrating a 5G module pairing procedure in accordance with an exemplary embodiment;

FIG. 5 is a logical block diagram illustrating a 5G module time pairing in accordance with an exemplary embodiment;

FIG. 6 is a schematic diagram illustrating a 5G module providing time information to a protection device in accordance with an exemplary embodiment;

FIG. 7 is a schematic diagram illustrating an internal structure of a current differential protection data synchronization system based on 5G network time service according to an exemplary embodiment;

fig. 8 is an overall schematic diagram of a 5G network time service current differential protection data synchronization system according to an exemplary embodiment.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

in order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.

The current differential protection in the power grid has extremely high requirements on time synchronization, and when the 5G network realizes data interaction on two sides of a line, the time service function of the 5G network can also provide an optional idea for solving the data synchronization problem of the scene, so that the problem can be perfectly solved by the high-precision time information of the 5G network.

The synchronization is realized by two steps: (1) high-precision time synchronization is realized among the 5G base stations; (2) and the equipment on the two sides of the line is independently timed by the base stations in the coverage areas of the equipment. Through the two steps, the equipment on two sides of the line can obtain high-precision time synchronization. To meet the requirements of the communication service itself, step (1) has been implemented. The invention provides a specific implementation method for the time service function of a base station to terminal equipment, which fully utilizes the existing time related information in a 5G network to compensate transmission time delay, provides high-precision time information for a differential protection device on the basis of the transmission time delay, and reasonably utilizes the high-precision time information to realize synchronous sampling of protection devices at two sides of a line.

Fig. 1 is a flow chart illustrating a method for current differential protection data synchronization based on 5G network time-pairing according to an exemplary embodiment. As shown in fig. 1, a method for synchronizing current differential protection data based on a 5G network time synchronization provided in an embodiment of the present invention is provided, where the 5G network implements base station synchronization through high-precision time synchronization networking. The flow of time information is shown in fig. 2, the invention provides a specific implementation method for the time service function of a base station to a terminal device, and the synchronous sampling of the protection devices on two sides of a line is implemented by using the high-precision time information, which comprises the following steps:

in step S1, the 5G module of the current differential protection device receives the broadcast message SIB9 of the 5G base station and the timing advance.

Process for acquiring base station side time signal (system message block SIB9 and timing advance TA) as shown in fig. 3, the 5G module receives system message block SIB9 containing information related to GPS time and coordinated universal time by periodic broadcast. The base station determines the distance between the uplink signal and the position of the base station through power detection, obtains a TA value, and feeds the TA value back to the 5G module through downlink information.

Step S2, calculating the propagation delay tau of the broadcast message according to the state of the broadcast message and the timing advance;

step S3, correcting the local clock of the current differential protection device based on the broadcast message SIB9 and the propagation delay tau;

and step S4, taking the corrected local clock as a reference, and providing time information and an absolute time tag required by synchronous sampling of current differential protection data for the current differential protection device by the 5G module.

The corrected local clock is used as a reference, the 5G module outputs IBIG-B code and other time-setting signals to provide time information required by synchronous sampling for the protection device; and the data packet is tagged with an absolute time tag. The specific procedure of step S4 is shown in fig. 6.

As a possible implementation manner of this embodiment, calculating the propagation delay τ of the broadcast message according to the state of the broadcast message and the timing advance includes:

firstly, detecting the 5G signal intensity, and judging whether the time service requirement is met;

and judging the state of the base station, when the 5G module is initialized, determining a TA value by measuring the received Preamble by the base station, and sending the 5G module through a TA Command field (total 12 bits, and the corresponding TA index value is 0-3846). When the subcarrier spacing is 2^μTime advance TA granularity at 15KHz (0, 1,2 …) is T_μ＝16*64*T_C/2^μ，T_CThe minimum time unit of 5G NR is 0.5086ns, TA x T for random access_μIs the actual adjustment value. As the TA value is defined, the propagation delay is substantially doubled, so that the base station can obtain the 5G moduleThe propagation delay is calculated by the formula:

τ₁＝(TA×T_μ)/2

when the 5G module is in a connection state, considering factors such as mobility and crystal oscillator offset of the 5G module, the TA still needs to be updated, the base station determines the offset of the TA at the moment by measuring the uplink transmission signal, the offset TA is sent to the 5G module through a TA Command field (total 6 bits, corresponding TA index value is 0-63), and the 5G module stores the actual adjustment value N of the TA of the previous time_TA,oldAfter receiving the new offset TA value, a new actual adjustment value is calculated: n is a radical of_TA,new＝N_TA,old+(TA-31)*T_μ. From this, the propagation delay calculation formula in this case is:

τ₂＝[N_TA,old+(TA-31)×T_μ]/2

wherein TA is the timing advance T_μ＝16*64*T_C/2^μ，T_CIs the minimum time unit of 5G NR,. mu.0, 1,2 …, N_TA,oldAnd the actual adjustment value of the timing advance TA of the 5G module in the previous time.

As a possible implementation manner of this embodiment, modifying the local clock of the current differential protection device based on the broadcast message SIB9 and the propagation delay τ includes:

calculating the clock deviation between the base station side and the local clock; 5G Module according to t₁、t₂And calculating clock deviation by the propagation delay tau, correcting the local clock at intervals, wherein the time deviation delta t is calculated by the following formula:

Δt＝t₁-t₂-τ

wherein, tau is the propagation delay of the broadcast message, including the propagation delay tau₁Or propagation delay tau₂。

And correcting the local clock according to the deviation between the base station side and the local clock. The implementation of the correction of the local clock is shown in fig. 4.

And the 5G module calculates the time deviation according to the analyzed time correlation quantity and corrects the local clock. This step can be implemented by setting a threshold value T for the clock skew₀Comparing the clock offset with T₀Fig. 5 shows a logic flow chart of the time service function of the base station to the terminal device.

As shown in fig. 7, the current differential protection data synchronization system based on 5G network time synchronization according to the embodiment of the present invention includes a 5G module, a clock module, a synchronous sampling control module, a data acquisition module, and a CPU processor;

the 5G module acquires and decodes a broadcast message SIB9 and a timing advance TA from a 5G base station and marks a time stamp t on the receiving time of the broadcast message SIB9₂(ii) a Wherein, the GPS time and the coordinated universal time in the SIB9 record the time t when the base station transmits SIB9 broadcast message₁The clock on the base station side is used as the standard.

The 5G module simultaneously performs data interaction with the opposite end of the line;

the clock module is used for correcting the local clock based on the time correlation quantity analyzed by the 5G module and outputting a time tick signal;

the synchronous sampling control module is used for receiving the high-precision time information of the clock module and outputting sampling pulses meeting requirements;

the data acquisition module is used for converting the acquired current differential protection data analog quantity into a corresponding digital quantity;

and the CPU processor sets absolute time labels for the data packets, analyzes and processes the local data and the end data, and performs relay protection measurement, logic and control.

As a possible implementation manner of this embodiment, the clock module includes a local clock, a data storage unit, a time synchronization unit, and an output unit; the data storage unit stores the time correlation quantity analyzed by the 5G module; the time synchronization unit calculates the propagation delay tau of the broadcast message according to the time advance TA and calculates the clock difference between the base station side and the 5G module, the clock module corrects the local clock according to the clock difference, and the output unit outputs a time setting signal: IRIG-B code, timing pulse, serial port time information and the like.

In this embodiment, the clock module outputs a B-code time tick signal, and after decoding, the clock module provides a pulse per second (1PPS) for the synchronous sampling control module, and the synchronous sampling control module outputs a synchronous sampling pulse.

As a possible implementation manner of this embodiment, the calculation formula of the time deviation Δ t is:

Δt＝t₁-t₂-τ

As a possible implementation manner of this embodiment, the propagation delay of the broadcast message includes:

when the 5G module is initialized, the propagation delay is:

τ₁＝(TA×T_μ)/2

when the 5G module is in the connected state, the propagation delay is:

τ₂＝[N_TA,old+(TA-31)×T_μ]/2

in the formula, TA is timing advance, and when the 5G module is in an initialized state, the TA index value is 0-3846; in the 5G module connection state, the TA index value is 0-63. T is_μGranularity of timing advance TA, T_μ＝16*64*T_C/2^μ，T_CIs the minimum time unit of 5G NR,. mu.0, 1,2 …, N_TA,oldAnd the actual adjustment value of the timing advance TA of the 5G module in the previous time.

As a possible implementation manner of this embodiment, the clock module supports an external input time synchronization manner. The clock module can be used for accurately keeping time for a long time by depending on a local atomic clock, can still output high-precision time under the condition of 5G communication alarm, and supports an external input time setting mode for increasing redundant configuration.

Fig. 7 is a schematic diagram of the entire current differential protection data synchronization system based on 5G network timing in this embodiment.

The technical scheme provided by the invention can solve the problem that the existing data synchronization mode cannot adapt to 5G current differential protection, and has the characteristics of high precision, low cost and flexible deployment.

The foregoing is only a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements are also considered to be within the scope of the present invention.