CN109714123B - Time synchronization method and system of transient wave recording device of distribution network - Google Patents

Abstract

The invention relates to the technical field of power systems, and specifically discloses a time synchronization method for a distribution network transient wave recording device, wherein the distribution network transient wave recording device includes a plurality of endpoints, and each endpoint includes three acquisition ends and one The time synchronization method of the convergence terminal and the distribution network transient wave recording device includes: the convergence terminal of each endpoint compiles different pseudo-random codes for the three acquisition terminals of the terminal respectively; the convergence terminal synchronizes the pseudo-random code of the terminal with the time The information is encoded and sent to the collection end of the endpoint; each collection end of each endpoint receives the time synchronization information carrying the pseudo-random code and decodes it, and identifies its own time synchronization information according to different pseudo-random codes. The invention also discloses a time synchronization system of the distribution network transient wave recording device. The time synchronization method of the distribution network transient wave recording device provided by the invention has the characteristics of less occupied wireless bandwidth, good anti-interference, high time synchronization accuracy and wide range of action.

Description

A time synchronization method and system for a distribution network transient wave recording device

technical field

The invention relates to the technical field of electric power systems, in particular to a time synchronization method of a distribution network transient wave recording device and a time synchronization system of a distribution network transient wave recording device.

Background technique

The fault location of the distribution network requires multi-point control, three-phase multi-point recording of fault signals, comprehensive judgment and fault location location. time scale remains the same.

For the time synchronization applied to the transient recording device of the overhead transmission line of the distribution network, due to the complex electromagnetic radiation environment around the overhead transmission line, there is a certain interference to the communication between the radio frequency equipment, and each endpoint of the distribution network fault recording device It consists of three acquisition units and a collection unit. The three acquisition units detect each phase line respectively, and then the data is transmitted to the collection unit. However, the time of each endpoint of the distribution network fault recorder must have high-precision time synchronization to ensure the real-time and validity of the recorded data. Therefore, it is necessary to design a high-precision time synchronization method in the distribution network environment with complex electromagnetic environment, large signal interference and high transmission delay.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a time synchronization method for a distribution network transient wave recording device and a time synchronization system for a distribution network transient wave recording device, so as to solve the problem of the existing problems in technology.

As a first aspect of the present invention, a time synchronization method of a distribution network transient wave recording device is provided, wherein the distribution network transient wave recording device includes a plurality of endpoints, and each endpoint includes three acquisition ends and A convergence end, the time synchronization method of the distribution network transient wave recording device includes:

The convergent end of each endpoint compiles different pseudo-random codes for the three collection ends of the endpoint respectively;

The convergence end encodes the pseudo-random code and time synchronization information of the endpoint and sends it to the collection end of the endpoint;

Each collection end of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving the time synchronization information, and identifies respective time synchronization information according to different pseudo-random codes.

Preferably, the time synchronization method of the distribution network transient wave recording device further comprises:

The convergence terminal performs time stamping when sending the time synchronization information carrying the pseudo-random code;

The sink terminal performs time stamping when receiving the time synchronization information carrying the pseudo-random code.

Preferably, each collection end of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving, and identifies the respective time synchronization information according to different pseudo-random codes, including:

The acquisition end performs discrete Fourier calculation to obtain the frequency domain data of the acquisition end;

Multiplying and analysing the frequency domain data of the collection terminal and the frequency domain data of the pseudo-random code to obtain parsed data;

The analytical data is subjected to inverse Fourier calculation to obtain the time domain data of the pseudorandom code;

The time-domain data is averaged and the difference is obtained to obtain time synchronization information of the pseudo-random code;

Determine whether the time synchronization information of the pseudo-random code matches;

If there is a match, the index number and peak time of the pseudo-random code are identified.

As a second aspect of the present invention, a time synchronization system of a distribution network transient wave recording device is provided, wherein the time synchronization system of the distribution network transient wave recording device includes: a collection device and a convergence device. The device is connected to the convergence device, the acquisition device includes three acquisition terminals, and the convergence device includes one convergence terminal;

The convergence terminal is used to compile different pseudo-random codes for the three acquisition terminals connected to it, and to encode the pseudo-random code and the time synchronization information and send them to the threshold-connected acquisition terminal;

The collecting end is used for decoding after receiving the time synchronization information carrying the pseudo-random code, and identifying respective time synchronization information according to different pseudo-random codes.

The time synchronization method of the distribution network transient wave recording device provided by the present invention, through the unification of the time synchronization at the convergence end, and the setting of different pseudorandom codes at the convergence end, has high real-time performance, and can effectively resist the reflection caused by buildings and solid objects. The multipath effect can effectively ensure the uniqueness of the time synchronization information and reduce the transmission delay of the time synchronization information. At the same time, the method of the invention has the characteristics of less wireless bandwidth, good anti-interference, high timing accuracy and wide range of action.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached image:

FIG. 1 is a flowchart of a time synchronization method of a distribution network transient wave recording device provided by the present invention.

FIG. 2 is a schematic structural diagram of the time synchronization system of the distribution network transient wave recording device provided by the present invention.

FIG. 3 is a schematic diagram of time synchronization between a sink terminal and an A-phase acquisition terminal provided by the present invention.

FIG. 4 is a flowchart of a specific implementation manner of the time synchronization method of the distribution network transient wave recording device provided by the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

As a first aspect of the present invention, a time synchronization method of a distribution network transient wave recording device is provided, wherein the distribution network transient wave recording device includes a plurality of endpoints, and each endpoint includes three acquisition ends and A convergence end, as shown in Figure 1, the time synchronization method of the distribution network transient wave recording device includes:

S110, the aggregation end of each endpoint compiles different pseudorandom codes for the three collection ends of the endpoint respectively;

S120, the convergence end encodes the pseudo-random code and time synchronization information of the endpoint and sends it to the collection end of the endpoint;

S130. Each collection end of each endpoint receives the time synchronization information carrying the pseudo-random code and decodes it, and identifies respective time synchronization information according to different pseudo-random codes.

The time synchronization method of the distribution network transient wave recording device provided by the present invention, through the unification of the time synchronization at the convergence end, and the setting of different pseudorandom codes at the convergence end, has high real-time performance, and can effectively resist the reflection caused by buildings and solid objects. The multipath effect can effectively ensure the uniqueness of the time synchronization information and reduce the transmission delay of the time synchronization information. At the same time, the method of the invention has the characteristics of less wireless bandwidth, good anti-interference, high timing accuracy and wide range of action.

Specifically, the time synchronization method of the distribution network transient wave recording device further includes:

The convergence terminal performs time stamping when sending the time synchronization information carrying the pseudo-random code;

The sink terminal performs time stamping when receiving the time synchronization information carrying the pseudo-random code.

Specifically, each collection end of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving, and identifies the respective time synchronization information according to different pseudo-random codes, including:

The acquisition end performs discrete Fourier calculation to obtain the frequency domain data of the acquisition end;

Multiplying and analysing the frequency domain data of the collection terminal and the frequency domain data of the pseudo-random code to obtain parsed data;

The analytical data is subjected to inverse Fourier calculation to obtain the time domain data of the pseudorandom code;

The time-domain data is averaged and the difference is obtained to obtain time synchronization information of the pseudo-random code;

Determine whether the time synchronization information of the pseudo-random code matches;

If there is a match, the index number and peak time of the pseudo-random code are identified.

The time synchronization method of the distribution network transient wave recording device provided by the present invention will be described in detail below with reference to FIGS. 2 to 4 .

When a node sends clock information to its neighbor nodes, many nodes in its broadcast domain can also receive this information, and the same node can receive clock information of many other neighbor nodes when receiving clock information. Therefore, in order to further improve the accuracy of time synchronization, the algorithm needs to have fast convergence speed, less message exchange, low energy consumption, and high efficiency of time information synchronization.

In the embodiment of the present invention, a pseudo-random code is added before the time synchronization information to ensure that the three-phase collecting terminals receive different time synchronization information. Pseudo-random coding ensures the effective transmission of time information. On the one hand, it has strong anti-interference, and on the other hand, it ensures the rapid calibration of removing time information. The aggregation end assigns different pseudo-random codes Random(i) to different collecting ends, where i is the number of the three-phase collecting ends, the pseudo-random codes have good cross-correlation with each other, and the collecting ends distinguish the corresponding time synchronization information.

During the specific implementation, the convergence terminal compiles different pseudo-random codes for the three acquisition terminals, encodes them with the time synchronization information, and sends the time synchronization information carrying the pseudo-random codes from the convergence terminal. The collecting end receives the time synchronization signals sent by the gathering end on No. 1 to 3, decodes them, and identifies their respective time synchronizations through different pseudo-random codes. At the same time, the gathering end and the gathering end will mark the corresponding time.

Taking the time synchronization between the sink and the phase-A acquisition terminal as an example, the synchronization time from the sink to the phase-A acquisition terminal is ta0, the sending time is recorded as ta1, the time when the phase-A acquisition terminal receives the synchronization signal is ta2, and the time for time synchronization is ta3, the time when the A-phase collector sends back the synchronization time to the sink is ta4, corrects the time offset, and then sends it back to the A-phase collector. Since the pseudo-random code improves the transmission efficiency of the time synchronization signal, it can be considered that the transmission delay is zero. The synchronization time of the A-phase acquisition terminal is:

Ta = ta1+(ta3-ta2)/2,

In the same way, the B-phase acquisition terminal time Tb = tb1+(tb3-tb2)/2 can be obtained,

In the same way, the C-phase acquisition terminal time Tc = tc1+(tc3-tc2)/2 can be obtained.

The encoding and decoding process is that the acquisition end first performs discrete Fourier calculation to obtain the corresponding frequency domain data N. Multiply N and the random code Random(i) frequency domain data to obtain the corresponding analytical O, and then perform inverse scattering Fourier calculation on the analytical data O to obtain the time domain data R of the pseudo-random code. The average difference method of the time domain data R of the pseudorandom code is used to obtain whether the time synchronization signal in the time domain data R of the pseudorandom code matches. If the match identifies the index number i of Random(i) and the time T of the peak. If there is no other random code Random(i) to be matched again, until a match is found.

In order to realize the point-to-point time synchronization capability of multiple devices, the time synchronization method of the distribution network transient wave recording device provided by the present invention adopts a pseudo-random noise encoding method with excellent autocorrelation and cross-correlation characteristics, the code phase is aligned, and the wide pulse is restored. The code phases are not aligned and you only get noise. After using pseudo-random coding, its excellent cross-correlation can ensure good orthogonality of multi-acquisition ends, realize code sequence distinction of multi-acquisition ends, and by assigning different pseudo-random codes to different sinks, these pseudo-random The codes have good cross-correlation with each other, and the collecting end distinguishes the corresponding gathering end according to different pseudo-random codes. At the same time, the code sequence distinction of multiple acquisition terminals can realize that the time synchronization signals of the aggregation terminal are not interfered with each other, and there is no need for peak shift in time, which reduces the overall time required for time synchronization of the acquisition terminals, and ensures that the real-time performance of the system is not affected by the wireless transmission distance. Impact.

In order to improve the accuracy and reliability of time synchronization, the orthogonality of the coding is used to make the multipath signal separable. Considering that the direct path signal arrives first, the signal component that arrives first is selected, and other components are discarded to solve the problem of the radio frequency signal. Multipath effects due to reflections from objects indoors.

Compared with the prior art, the time synchronization method of the distribution network transient wave recording device provided by the present invention significantly improves the transmission efficiency of time synchronization information by adding pseudo-random coding, and effectively avoids the multipath interference of wireless radio frequency communication.

As a second aspect of the present invention, a time synchronization system of a distribution network transient wave recording device is provided, wherein the time synchronization system of the distribution network transient wave recording device includes: a collection device and a convergence device. The device is connected to the convergence device, the acquisition device includes three acquisition terminals, and the convergence device includes one convergence terminal;

The convergence terminal is used to compile different pseudo-random codes for the three acquisition terminals connected to it, and to encode the pseudo-random code and the time synchronization information and send them to the threshold-connected acquisition terminal;

The collecting end is used for decoding after receiving the time synchronization information carrying the pseudo-random code, and identifying respective time synchronization information according to different pseudo-random codes.

It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, without departing from the spirit and essence of the present invention, various modifications and improvements can be made, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (3)

1. a time synchronization method of a distribution network transient wave recording device, is characterized in that, the described distribution network transient wave recording device comprises a plurality of endpoints, and each endpoint comprises three acquisition ends and a convergent end, the described The time synchronization method of the distribution network transient wave recording device includes: The convergence end of each endpoint compiles different pseudo-random codes for the three collection ends of the endpoint respectively; The convergence end encodes the pseudo-random code and time synchronization information of the endpoint and sends it to the collection end of the endpoint; Each acquisition terminal of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving it, and identifies the respective time synchronization information according to different pseudo-random codes; Wherein, each acquisition end of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving, and identifies the respective time synchronization information according to different pseudo-random codes, including: The acquisition end performs discrete Fourier calculation to obtain the frequency domain data of the acquisition end; Multiplying and analysing the frequency domain data of the collection terminal and the frequency domain data of the pseudo-random code to obtain parsed data; The analytical data is subjected to inverse Fourier calculation to obtain the time domain data of the pseudorandom code; The time-domain data is averaged and the difference is obtained to obtain time synchronization information of the pseudo-random code; Determine whether the time synchronization information of the pseudo-random code matches; If there is a match, the index number and peak time of the pseudo-random code are identified. 2. The time synchronization method of the distribution network transient wave recording device according to claim 1, wherein the time synchronization method of the distribution network transient wave recording device further comprises: The convergence terminal performs time stamping when sending the time synchronization information carrying the pseudo-random code; The sink terminal performs time stamping when receiving the time synchronization information carrying the pseudo-random code. 3. A time synchronization system of a distribution network transient wave recording device, characterized in that the time synchronization system of the distribution network transient wave recording device comprises: acquisition equipment and convergence equipment, the acquisition equipment and the convergence equipment connection, the collection device includes three collection ends, and the aggregation device includes one aggregation end; The convergence terminal is used to compile different pseudo-random codes for the three acquisition terminals connected to it, and to encode the pseudo-random code and the time synchronization information and send them to the acquisition terminal connected to it; The collection terminal is used for decoding after receiving the time synchronization information carrying the pseudo-random code, and identifying respective time synchronization information according to different pseudo-random codes; Wherein, each acquisition end of each endpoint decodes the time synchronization information carrying the pseudo-random code after receiving, and identifies the respective time synchronization information according to different pseudo-random codes, including: The acquisition end performs discrete Fourier calculation to obtain the frequency domain data of the acquisition end; Multiplying and analysing the frequency domain data of the collection terminal and the frequency domain data of the pseudo-random code to obtain parsed data; The analytical data is subjected to inverse Fourier calculation to obtain the time domain data of the pseudorandom code; The time-domain data is averaged and the difference is obtained to obtain time synchronization information of the pseudo-random code; Determine whether the time synchronization information of the pseudo-random code matches; If there is a match, the index number and peak time of the pseudo-random code are identified.

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