CN112202491B - Data transmission method of 5G differential protection device - Google Patents

A data transmission method of a 5G differential protection device belongs to the technical field of relay protection of power systems. The method is completed based on a data processing device, the data processing device comprises a main controller module, a satellite time synchronization module, a FPAG module and a 5G network interface connected with a 5G communication module, and the method comprises the following steps: the sender calculates the acquisition time of the data and sends the data and the calculated acquisition time together; after receiving the data, the receiver calculates the waiting time according to the acquisition time, the expected sending time and the set time delay of the sender, and sends the received data to the differential protection device after the waiting time is reached. When the device and the method provided by the invention are used for upgrading the original optical fiber network into a 5G network, only the hardware device and the front-end processing software of data need to be updated on the original equipment, the core part of a software system does not need to be changed, the workload is greatly reduced, the research and development period is shortened, and the reliability does not need to be verified again.

Data transmission method of 5G differential protection device

Technical Field

The invention belongs to the technical field of power system relay protection, and relates to a data transmission method of a 5G differential protection device.

Background

In an electric power system, differential protection requires acquiring synchronous sampling data of equipment on two sides. In the conventional optical fiber differential protection device, the delay of optical signal transmission in the optical fiber is fixed delay, and the optical fiber differential protection device is generally not influenced by the external environment. By measuring the channel delay, the received contralateral data is calculated on the local side time axis, and the synchronization of the sampling data can be realized.

The traditional differential protection device using optical fiber as data transmission medium has been used in large quantity in the field, and the reliability has been verified. However, the special optical fiber pipeline is difficult to lay, the construction cost is high, and some areas do not have optical fiber laying conditions, so that certain restriction is brought to the development of differential protection technology. Secondly, when the optical fiber is broken, the broken position is difficult to search, and the maintenance cost is high.

At present, 5G networks are put into commercial use, the end-to-end delay in 5G network slices reaches within 10 milliseconds, and the characteristic of low delay is favorable for realizing a differential protection function.

In a newly-built substation, a set of 5G differential protection device is respectively configured on two sides of a line, and the scheme is easy to realize by replacing a traditional optical fiber differential protection device.

Although the 5G network has the characteristic of low delay, the delay is unstable, and the optical fiber differential protection device is realized by just utilizing the stability of the optical fiber transmission delay. The 5G network is used for replacing optical fibers, but the system period of software which is newly developed to meet the requirements is long, and the reliability needs to be verified.

Disclosure of Invention

The invention aims to provide equipment and a method, which replace optical fiber communication with 5G communication on the basis of using an original software system and meet the requirement of stable time delay of communication.

In order to achieve the purpose, the invention adopts the following technical scheme: a data transmission method of a 5G differential protection device is completed based on a data processing device, the data processing device comprises a main controller module and a satellite time synchronization module, the main controller module comprises a satellite time synchronization function module connected with the satellite time synchronization module, and the key is that: the data processing device also comprises an FPAG module and a 5G network interface connected with the 5G communication module, and the main controller module also comprises a data processing module connected with the FPGA module and an Ethernet control function module connected with the 5G network interface.

Furthermore, the data processing module comprises a differential data processing functional module and a 5G data conversion and transmission functional module; the FPGA module comprises a data buffer module, a differential receiving and data encryption module and a 5G data receiving and data decryption module.

Further, a stable time delay parameter T3 is set; the data transmission method comprises the following steps:

and (3) data transmission: the 5G data conversion and transmission function module is used for encrypting the data after the differential data receiving and encrypting module receives the differential data of the main controller, calculating to obtain the absolute time generated by generating the differential data and transmitting the absolute time to the main controller; and the 5G data conversion and transmission functional module transmits the differential data and the absolute time for generating the differential data to the 5G network interface through the Ethernet control module.

And (3) receiving data: the 5G data conversion and transmission function module receives data received by the 5G network interface, calculates data buffering time according to T3 after de-framing, calculates time consumed by the FPGA data buffering module for sending data, and sends the data to the 5G data receiving and data decryption module of the FPGA after calculation; the 5G data receiving and data decrypting module completes data decrypting processing and transmits the data decrypting processing to the data buffering module; the data buffer module calculates the waiting time, and sends data to the differential protection data processing function module of the main controller after the waiting time is reached.

When receiving the data, calculating the time of generating differential data, and sending the time and the data of generating differential data to the opposite side through a 5G communication network; after the data frame of the 5G module is received on the opposite side, the waiting time is set according to the time generated by the differential data and the fixed time delay, so that the fixed time delay is realized when the data is transmitted between the two differential protection devices.

Has the advantages that: by adopting the technical scheme provided by the invention, when the 5G network is upgraded on the basis of the original optical fiber network, only the hardware device and the front-end processing software of the data need to be updated on the original equipment, the core part of the software system does not need to be changed, the workload is greatly reduced, the research and development period is shortened, and the reliability does not need to be verified again.

Drawings

FIG. 1 is a schematic diagram of the data processing apparatus,

fig. 2 is a time slot diagram of both sides of the transceiver.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, the data processing device includes a main controller module and a satellite time synchronization module, the main controller module includes a satellite time synchronization function module connected to the satellite time synchronization module, and the satellite time synchronization module is a GPS module or a beidou time synchronization module.

The FPGA has better time sequence and logic characteristics, so that the FPGA can be used for encrypting and decrypting data, ensuring the data security, buffering received data and achieving the purpose of stabilizing time delay.

The data processing device also comprises an FPAG module and a 5G network interface connected with the 5G communication module, and the main controller module also comprises a data processing module connected with the FPGA module and an Ethernet control function module connected with the 5G network interface.

The data processing module in the main controller module comprises a differential data processing functional module and a 5G data conversion and transmission functional module; the FPGA module comprises a data buffer module, a differential receiving and data encryption module and a 5G data receiving and data decryption module.

The 5G network interface comprises a MAC + PHY module and a SWITCH module, wherein the SWITCH module is connected with the RJ45 interface module and the 5G communication module. An RJ45 network port plug-in 5G CPE device can be used; A5G module may be built in as necessary. The main controller forms an Ethernet channel through MAC + PHY; the Ethernet channels are interconnected by using a SWITCH chip.

The liquid crystal display can carry out device parameter setting, and basic parameters comprise: the 5G terminal is selected and used, and comprises an external 5G CPE and an internal 5G module; setting and reading 5G terminal parameters, including a terminal MAC, a gateway and an APN; setting and reading the IP of the device and the IP of the opposite side device; the stable time delay parameter is set and read, and can be set to any value of 10ms-15 ms.

The main controller module is used as a central control of data flow to realize framing and unframing of data frames. And receiving GPS/Beidou time tick signals, thereby ensuring higher system time precision. And after receiving the FPGA data, the main controller module adds the time mark information of the current point and forms a UDP frame. The UDP frame is transmitted to the opposite-side data processing apparatus through the 5G network. Decoding the UDP frame by the side data processing device, and judging the frame sequence number and the timestamp; sending the application layer data to the FPGA for decryption processing; the FPGA carries out buffering processing on the data according to the set time delay value; and after the set time delay is reached, sending the data to a differential protection data processing functional module of the main controller.

And receiving and transmitting data.

The data processing devices on the side and the opposite side realize the communication function; a stable time delay parameter T3 is set in the data processing device, and T3 is the fixed time delay of data transmitted from the local side differential protection device to the opposite side differential protection device.

The 5G data conversion and transmission function module mainly comprises two parts of functions, namely receiving encrypted differential protection data, forming information such as absolute system time when the differential protection data are generated into a UDP frame form, transmitting the information to a 5G network interface through the Ethernet control module, and sending the information out through a 5G network; secondly, the following steps: receiving contralateral data received by the 5G network interface, calculating data buffering time according to the stable time delay parameter after de-framing, and calculating the count of a timer consumed by the FPGA data buffering module for sending data; and the 5G data receiving and data decrypting module is used for sending the data to the FPGA after the calculation is finished.

The data receiving and encrypting module in the FPGA module has the functions of: 1. and the 5G data conversion and transmission functional module receives the differential data of the main controller, encrypts the data, receives the timer count value consumed by decryption of the differential protection data and sends the timer count value to the main controller. 2. Receiving 5G data after the host controller deframed, data buffering time and timer count consumed by the data buffering module to send data; and finishing data decryption processing.

And the data buffer module in the FPGA module is used for calculating the data retention time, and the timer counts the data retention time and then sends the data to the differential protection data processing functional module of the main controller, so that the stable 5G time delay is realized.

The method comprises the steps of sending data and receiving the data.

And (3) data transmission: after receiving the differential data of the main controller, the differential data receiving and encrypting module encrypts the data, calculates the processing time and sends the processing time to the 5G data conversion and transmission function module of the main controller; the 5G data conversion and transmission function module transmits the differential data and the absolute time for generating the differential data to a 5G network interface through the Ethernet control module, and specifically comprises the following steps:

step S1, when the differential data starts to be received, a timer is started to count, and the timer frequency is Fr ≧ 10 MHz.

And the differential data receiving and encrypting module in the FPGA module receives the differential data of the main controller. When the transmitted data is detected, a timer is started, and the following processing is performed on the data.

And step S2, acquiring the data frame of the differential protection device and putting the data frame into a data buffer area.

And step S3, encrypting the acquired data frame, stopping counting after the encryption processing is finished, and acquiring the count Nr of the timer.

The above completes the processing of the data, and the processing time is determined by the counter. And processing data by the FPGA from the step S1 to the step S3, wherein the FPGA is not connected with the GPS/Beidou time tick signals. Wherein the step S1 starts the timer counting and the step S2 starts simultaneously, not in a sequential order.

And step S4, recording the current system time T1 of the acquired encrypted data, and calculating a received data timestamp Tr = T1-Nr/Fr.

This step is accomplished by the master controller module. Because the FPGA is not connected with the GPS/Beidou time synchronization signal, the system time cannot be acquired, and the time for receiving the differential protection data is calculated by timing of a counter.

Step S5 is to perform packing processing on the time stamp information Tr and the encrypted data.

Step S6, acquiring the MAC address of the device at the side, the MAC address of the 5G terminal, the IP address of the device at the side and the IP address of the device at the opposite side, and transmitting the packaged data to a 5G network interface for sending in a UDP frame form;

the 5G data conversion and transmission function module receives data received by the 5G network interface, calculates data buffering time according to T3 after de-framing, calculates time consumed by the FPGA data buffering module for sending data, and sends the data to the 5G data receiving and data decryption module of the FPGA after calculation; the 5G data receiving and data decrypting module completes data decrypting processing and transmits the data decrypting processing to the data buffering module; the data buffer module calculates the waiting time, and sends data to the differential protection data processing function module of the main controller after the waiting time is reached. The method specifically comprises the following steps:

and step R1, acquiring the opposite side UDP frame received by the 5G network interface.

Step R2, analyzing the data, reading the time stamp Tr of the received UDP frame, reading the current system time T2 and the stable time delay parameter T3, and calculating the data buffering time: Δ T = T3- (T2-Tr), Δ T is in μ s.

And simultaneously executing the step R3, calculating the count of the timer required by data transmission: ns = m × n, where m is the number of bytes of data in the UDP frame, and n is the timer count required for the FPGA to send one byte.

And step R4, starting a timer for counting, wherein the frequency of the timer is Fs, and Fs is ≧ 10 MHz.

Step R5, data decryption; and putting the decrypted data and the data buffering time delta T into a data buffer area.

When the count value Nc = Δ T × Fs-Ns, step R6 transmits the data to the differential protection data processing function module in the main controller module.

Referring to fig. 2, what the method is to achieve is that the time from the start of S1 to the completion of R6 is stabilized to T3.

And the timer count of the transmitting end determines the time consumed by the FPGA to execute the steps S2 and S3, and the main controller obtains the time Tr of the data arrival by acquiring the system time T1 after the step S3 is executed. The execution time of steps S4 to S6 may vary according to the size of the data frame, and the specific time does not affect the execution time. The time delay transmitted through 5G is unstable, i.e., the time between the completion of step S6 and the start of step R1 is unstable.

The steps R2 and R3 are executed simultaneously, R3 predicts the time required for sending data, and after R2 obtains the completion of R2 and R3, the residual time delta T of the fixed time delay T3 is reached from the step S1.

At this time, step R4 starts a timer to start counting; step 5 starts data decryption.

The above realizes the constancy of the transmission-reception interval.

Note that T3 is set to be greater than 5G end-to-end transmission delay + processing transmission time of data in the device. The end-to-end delay in the 5G network slice is within 10 milliseconds, and in the embodiment, T3 is set to 10-15ms, which can meet the requirement.

The timer frequencies Fr and Fs are crystal oscillator main frequencies configured for the FPGA.