Optical fiber longitudinal difference data transmission method and system for station domain relay protection device

Abstract

The invention relates to a station domain relay protection device optical fiber longitudinal difference data transmission method and system, and belongs to the field of electric power engineering relay protection automation. The transmission method comprises the following steps: integrating an STM-1 communication interface and an FPGA (Field Programmable Gate Array) on a substation territory protection device; when the station territory protection device sends an optical fiber longitudinal difference data message, the optical fiber longitudinal difference data required by each line is transmitted to the FPGA; framing the optical fiber longitudinal difference data by the FPGA according to an STM-1 communication interface protocol, and sending an optical fiber longitudinal difference data message formed after framing to opposite end protection devices of different lines through the STM-1 communication interface; after optical fiber longitudinal difference data messages sent by opposite end protection devices of different lines pass through the STM-1 communication interface, the optical fiber longitudinal difference data messages are sent and transmitted to the FPGA; and the FPGA processes the received optical fiber longitudinal difference data message to obtain net effective data corresponding to each line, and then transmits the net effective data to a station domain protection device. The method is simple and reliable when the optical fiber longitudinal differential protection is realized.

Description

Technical Field

[0001] This invention relates to a fiber optic longitudinal differential data transmission method and system for station-area relay protection devices, belonging to the field of power engineering relay protection automation. Background Technology

[0002] With the rapid advancement of substation protection automation towards digitalization and intelligence, substation-area protection fully leverages the data sharing advantages of smart substations. This not only saves resources by concentrating all bay protection into a single device but also comprehensively utilizes electrical quantities from multiple bays to achieve centralized backup and low-voltage / low-frequency load shedding within the substation. However, substation-area protection covers a large number of lines. Due to the complexity of optical fiber differential communication and sampling alignment methods, current substation-area protection systems generally lack optical fiber differential protection functionality. Alternatively, they employ a master-slave interconnection mode, requiring a dedicated slave device for each line protection line, specifically designed for optical fiber differential protection. The slave then transmits the optical fiber differential data to the master, resulting in a highly cumbersome and complex implementation. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for optical fiber longitudinal differential data transmission in a station-area relay protection device, so as to solve the problem of the cumbersome and complicated implementation of optical fiber longitudinal differential protection in the prior art.

[0004] To achieve the above objectives, the present invention includes: The present invention provides a fiber optic longitudinal differential data transmission method for a station-area relay protection device, comprising: integrating an STM-1 communication interface and an FPGA on the station-area protection device; The station protection device transmits the optical fiber longitudinal differential data required by each line to the FPGA; the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol, and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface. The fiber optic differential data messages sent by the protection devices at the opposite ends of different lines are transmitted to the FPGA through the STM-1 communication interface; the FPGA processes the received fiber optic differential data messages to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device.

[0005] Furthermore, the STM-1 communication interface connects to the SDH multiplexing access equipment via the SDH network. The SDH multiplexing access equipment is used to connect the protection devices at the other end of different lines. The station protection device informs the FPGA that there is fiber optic differential data to be sent by writing to the register; and detects whether the FPGA has received fiber optic differential data packets sent by the peer protection device of different lines by reading the register.

[0006] Furthermore, when sending fiber optic longitudinal differential data messages to the protection devices at the other end of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic longitudinal differential data messages. When receiving fiber optic longitudinal differential data messages from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic longitudinal differential data messages.

[0007] Furthermore, when sending fiber optic differential data messages to the protection devices at the other end of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic differential data messages, including: The CPU of the station protection device reads the sampling time of the FPGA at this moment; When the FPGA frames the fiber longitudinal differential data according to the STM-1 communication interface protocol and sends the framed fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface, the CPU reads the data transmission time of the FPGA at this time. The CPU calculates the actual transmission time of the fiber longitudinal differential data packet with the CPU as the reference based on the deviation between the sampling time and the data transmission time. When receiving fiber optic differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic differential data packets, including: After the FPGA receives several frames of fiber optic differential data messages, it triggers a CPU interrupt of the station protection device. After the interrupt is triggered, the CPU reads the first internal relative time of the FPGA in real time and compares it with the CPU's running time. The FPGA parses the second internal relative time when receiving different messages. The CPU calculates the actual reception time of the fiber optic differential data based on the first internal relative time, the running time, and the second internal relative time.

[0008] Furthermore, it also includes: using a fiber optic differential universal trapezoidal algorithm for sampling alignment between the station protection device and the protection devices at the opposite end of different lines; The station protection device is fixed as the main unit, and the sampling time is not adjusted. The protection devices at the opposite end of different lines are slave devices, and they are adjusted and aligned based on the calculated deviation from the sampling time of the station area protection devices.

[0009] The present invention provides a fiber optic longitudinal differential data transmission system for a station domain relay protection device, comprising: a station domain protection device, an STM-1 communication interface integrated on the station domain protection device, and an FPGA; The station protection device transmits the optical fiber longitudinal differential data required by each line to the FPGA; the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol, and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface. The fiber optic differential data messages sent by the protection devices at the opposite ends of different lines are transmitted to the FPGA through the STM-1 communication interface. The FPGA processes the received fiber optic differential data messages to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device.

[0010] Furthermore, it also includes: the STM-1 communication interface is also connected to the SDH multiplexing access equipment through the SDH network, and the SDH multiplexing access equipment is used to communicate with the protection devices at the other end of different lines; The station protection device informs the FPGA that there is fiber optic differential data to be sent by writing to the register; and detects whether the FPGA has received fiber optic differential data packets sent by the peer protection device of different lines by reading the register.

[0011] Furthermore, when sending fiber optic longitudinal differential data messages to the protection devices at the other end of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic longitudinal differential data messages. When receiving fiber optic longitudinal differential data messages from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic longitudinal differential data messages.

[0012] Furthermore, when sending fiber optic differential data messages to the protection devices at the other end of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic differential data messages, including: The CPU of the station protection device reads the sampling time of the FPGA at this moment; When the FPGA frames the fiber longitudinal differential data according to the STM-1 communication interface protocol and sends the framed fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface, the CPU reads the data transmission time of the FPGA at this time. The CPU calculates the actual transmission time of the fiber longitudinal differential data packet with the CPU as the reference based on the deviation between the sampling time and the data transmission time. When receiving fiber optic differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic differential data packets, including: After the FPGA receives several frames of fiber optic differential data messages, it triggers a CPU interrupt of the station protection device. After the interrupt is triggered, the CPU reads the first internal relative time of the FPGA in real time and compares it with the CPU's running time. The FPGA parses the second internal relative time when receiving different messages. The CPU calculates the actual reception time of the fiber optic differential data based on the first internal relative time, the running time, and the second internal relative time.

[0013] Furthermore, it also includes: using a fiber optic differential universal trapezoidal algorithm for sampling alignment between the station protection device and the protection devices at the opposite end of different lines; The station protection device is fixed as the main unit, and the sampling time is not adjusted. The protection devices at the opposite end of different lines are slave devices, and they are adjusted and aligned based on the calculated deviation from the sampling time of the station area protection devices.

[0014] The beneficial effects of this invention are as follows: As a pioneering invention, this invention provides a fiber optic longitudinal differential data transmission method and system for station-area relay protection devices. By integrating an STM-1 communication interface and an FPGA onto the station-area protection device, on the one hand, the communication interface can be directly connected to the station's telecommunications equipment and simultaneously perform fiber optic longitudinal differential communication with multiple line-end protection devices, simplifying the wiring and making the implementation simple and reliable; on the other hand, by fully utilizing the real-time and parallel processing advantages of the FPGA, fiber optic longitudinal differential communication between station-area protection and multiple line conventional protections can be realized, improving the speed, reliability, and accuracy of the station-area protection device in clearing line faults, making it simple and reliable. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a fiber optic longitudinal differential data transmission system for a station-area relay protection device provided in an embodiment of the present invention; Figure 2 This is a schematic flowchart of a fiber optic longitudinal differential data transmission method for a station-area relay protection device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of an FPGA sending optical fiber data packets according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a framing process provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of an FPGA receiving optical data packets according to an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0017] The concept of this invention lies in integrating an STM-1 communication interface and an FPGA onto a station protection device. The station protection device transmits the required fiber optic differential data for each line to the FPGA. The FPGA frames the fiber optic differential data according to the STM-1 communication interface protocol and sends the framed fiber optic differential data packets to the peer protection devices of different lines via the STM-1 communication interface. The fiber optic differential data packets sent by the peer protection devices of different lines are transmitted to the FPGA via the STM-1 communication interface. The FPGA processes the received fiber optic differential data packets to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device. By integrating the STM-1 communication interface and the FPGA onto the station protection device, on the one hand, the communication interface can be directly connected to the station's telecommunications equipment and simultaneously perform fiber optic differential communication with multiple peer protection devices on different lines, simplifying the wiring and making the implementation simple and reliable. On the other hand, by fully utilizing the real-time and parallel processing advantages of the FPGA, fiber optic differential communication between the station protection and the conventional protection of multiple lines can be realized, improving the speed, reliability, and accuracy of the station protection device in clearing line faults, making it simple and reliable.

[0018] An embodiment of a fiber optic longitudinal differential data transmission method for a station-area relay protection device: The fiber optic longitudinal differential data transmission method for a station-area relay protection device provided in this embodiment of the invention relies on the fiber optic longitudinal differential data transmission system of the station-area relay protection device. The following is a detailed explanation... Figure 1 Let me first introduce the data transmission system.

[0019] Figure 1 This is a schematic diagram of the structure of a fiber optic longitudinal differential data transmission system for a station-area relay protection device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the data transmission system includes: a station domain protection device and an STM-1 communication interface and a field-programmable gate array (FPGA) (not shown) integrated on the station domain protection device. The STM-1 communication interface connects to the protection devices at the other end of different lines through a Synchronous Digital Hierarchy (SDH) network and SDH multiplexing access equipment.

[0020] As an alternative implementation, the FPGA may not be integrated into the station protection device, and the present invention does not impose any particular limitation on this.

[0021] The STM-1 communication interface is a basic transmission module in SDH technology, with a rate of 155.520 Mbps. The fiber optic longitudinal differential communication rate for conventional line protection is 2.048 Mbps. Therefore, one STM-1 communication interface can support the multiplexing and demultiplexing of 63 2.048 Mbps tributary interfaces. Thus, one STM-1 communication interface of the station protection device can simultaneously conduct fiber optic longitudinal differential communication with the protection devices on the opposite side of 63 lines, improving communication efficiency.

[0022] The encoding and decoding processes of the link layer HDLC encoding and physical layer Manchester code or other mBnB encoding commonly used for the 2.048Mbps tributary messages of each line can also be implemented in the FPGA, which reduces the CPU load and improves the encoding efficiency.

[0023] Among them, the STM-1 communication interface integrated in the station protection device is directly interconnected with the telecommunications-dedicated communication equipment in the substation through single-mode optical fiber. This eliminates the need for conventional line protection to access the telecommunications-dedicated communication equipment through optical fiber multiplexing access equipment, saving steps and making the communication link simpler.

[0024] The STM-1 communication interface and FPGA are both integrated on the CPU board of the station protection device. The CPU is a ZYNQ7Z020 chip from Xilinx.

[0025] The logic functions of the STM-1 communication interface are mainly implemented within the FPGA on the PL side (not shown) of the system-on-chip. The PL side and the PS side of the system-on-chip communicate via the AXI bus. Here, the PL side refers to the programmable logic section, and the PS side refers to the processing system section.

[0026] The multiplexing and decomposition process of the STM-1 communication interface is implemented through an FPGA chip. By leveraging the parallel processing advantages of the FPGA, the multiplexing and decomposition process of STM-1 interface messages can be simplified.

[0027] Among them, the sampling alignment between the station protection device and the peer protection device of different lines is performed using the fiber optic differential universal trapezoidal algorithm; the station protection device is fixed as the master and the sampling time is not adjusted; the peer protection device of different lines is the slave and is adjusted and aligned according to the calculated deviation of the sampling time from the station protection device.

[0028] As an optional implementation, the station protection device also integrates a photoelectric conversion module for converting optical signals into electrical signals and a serial-to-parallel conversion module for performing serial-to-parallel conversion.

[0029] The photoelectric conversion module uses Chengdu Yuguang's GTLS-1303-15DI chip; the serial-to-parallel conversion module uses a PHY chip, specifically EXAR's XRT91L31 chip.

[0030] The FPGA includes: an AXI data receiving module, a multi-level data buffer module, a message parsing and transfer module, an HDLC encoding module, a Manchester encoding module, a C12 tributary message generation module, a VC4 message generation module, and an STM-1 framing and transmission module, which can transmit the fiber optic differential data of the station protection device to the protection devices at the other end of different lines.

[0031] The FPGA also includes: an STM-1 receiving module, a VC4 frame extraction module, a VC4 frame parsing and transfer module, a C12 positioning parsing module, a Manchester code decoding module, an HDLC decoding module, and an AXI data transmission module, to transmit optical data packets sent by the peer protection devices of different lines to the station domain protection device.

[0032] The following is combined Figures 2-5 This invention describes the specific process of a fiber optic longitudinal differential data transmission method for a station-area relay protection device provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic flowchart of a fiber optic longitudinal differential data transmission method for a station-area relay protection device provided in an embodiment of the present invention, as shown below. Figure 2 As shown, when the station protection device transmits fiber optic differential data to each peer protection device: the station protection device transmits the fiber optic differential data required by each line to the FPGA; the FPGA frames the fiber optic differential data according to the STM-1 communication interface protocol, and sends the framed fiber optic differential data message to the peer protection device that is sent to different lines through the STM-1 communication interface.

[0034] When each peer protection device transmits fiber optic differential data to the station protection device: the fiber optic differential data packets sent by the peer protection devices of different lines are transmitted to the FPGA after passing through the STM-1 communication interface; the FPGA processes the received fiber optic differential data packets to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device.

[0035] The station protection device informs the FPGA to send fiber optic differential data by writing to the register; and detects whether the FPGA has received fiber optic differential data packets sent by the peer protection device of different lines by reading the register.

[0036] Figure 3 This is a schematic diagram of a process for sending fiber optic data packets using an FPGA, as provided in an embodiment of the present invention. Figure 3As shown, Figure 3 (a) in the diagram represents the process of the FPGA putting data into the transmit buffer. Figure 3 (b) in the diagram represents the process of the FPGA framing and sending the data.

[0037] Specifically, such as Figure 3 As shown in (a), the CPU of the station protection device first stores the fiber optic differential data that needs to be sent to the peer protection devices on different lines into the agreed DDR storage space, and informs the FPGA through the AXI interface. The FPGA can determine whether data is being transmitted through the AXI interface. If not, it continues monitoring; if so, it can directly access the DDR storage space and obtain the fiber optic differential data through the AXI data receiving module. The message parsing and transfer module parses the fiber optic differential data received by the AXI data receiving module according to the internal agreed protocol, and transfers the parsed fiber optic differential data to 63 independent transmission buffers corresponding to the 63 branches. Among them, the AXI interface and data buffer are mainly used to realize the data interaction between the FPGA and the CPU.

[0038] like Figure 3 As shown in (b), after being transferred to the corresponding buffer, the FPGA starts to determine whether framing needs to be initiated. If not, it continues to determine whether the framing needs to be initiated. If so, it determines whether the fiber longitudinal differential data of branch n has been sent. If it has been sent, the fiber longitudinal differential data of that branch is read, the HDLC encoding / decoding module performs HDLC encoding on the fiber longitudinal differential data of that branch, and the Manchester encoding module performs Manchester encoding on the HDLC encoded data. If it has not been sent, idle data is filled into branch n, the idle data of that branch is read, the HDLC encoding / decoding module performs HDLC encoding on the idle data of that branch, and the Manchester encoding module performs Manchester encoding on the HDLC encoded data. Here, n takes any integer from [1, 63].

[0039] After the Manchester encoding is completed, the data is transferred to the buffer of the corresponding branch. Then, it is read and it is determined whether all the data of the 63 branches have been fully encoded in Manchester. If all of them have been fully encoded, the winding encoding is performed, the transmission time is recorded, and the data is transmitted. If not all of them have been fully encoded, it is determined whether the fiber longitudinal differential data of branch n++ has been transmitted. The process of reading data, encoding, and storing the data is repeated.

[0040] The C12 generation module will process the HDLC-encoded and Manchester-encoded data according to... Figure 4 The multiplexing and framing are performed in a manner that allows each branch to be configured by the CPU through registers.

[0041] in, Figure 4 This is a structural diagram of a framing process provided by an embodiment of the present invention, as shown below. Figure 4 As shown, this process is required by the standard protocol. From left to right, it is the decomposition process of the STM-1 message; from right to left, it is the framing process of the STM-1 message. Taking the framing process as an example, the tributary message to be transmitted is encapsulated in C12 according to the standard requirements. Messages sent to different peer devices are encapsulated in different C12s. After adding low-order channel overhead to C12, VC12 is generated. After adding tributary unit pointers to VC12, TU-12 is generated. Three sets of TU-12 are encapsulated according to byte interleaving requirements to generate TUG-2. Seven sets of TUG-2 are encapsulated with byte interleaving to generate TUG3. After adding pointers to three sets of TUG3, AU4 is generated. Finally, section overhead is added to generate STM-1. In short, one frame of STM-1 message can correspond to 63 tributary messages, and one station protection device can simultaneously correspond to 63 peer tributary devices.

[0042] Figure 5 This is a schematic diagram of an FPGA receiving optical data packets according to an embodiment of the present invention, as shown below. Figure 5 As shown, Figure 5 (a) in the diagram represents a flowchart illustrating the process by which the FPGA processes the fiber optic differential data message when it receives the fiber optic differential data message sent by the peer protection device. Figure 5 (b) in the diagram represents the process by which the FPGA transmits the processed data to the CPU.

[0043] like Figure 5 As shown in (a), the FPGA first determines whether fiber optic differential data packets have been received. If not, it continues to determine whether they have been received. If so, the STM-1 receiving module receives and descrambles the serial fiber optic differential data packets. The VC4 frame extraction module extracts the payload packet VC4 in framed mode according to the management unit pointer in the STM-1 packet. The VC4 frame parsing and transfer module decomposes the tributary packets according to the VC channel overhead. The FPGA needs to determine whether all 63 fiber optic differential data packets from the peer protection device have been decomposed. If all decomposition is complete, the decomposed packets are first decoded using Mann code, and then HDLC decoded to obtain the net valid data of each tributary. The C12 positioning and parsing module extracts the net valid data of each tributary according to the tributary unit pointer in the packet and transfers it to the receiving buffer corresponding to that tributary. If not all decomposition is complete, the decomposition continues.

[0044] like Figure 5As shown in (b), after transferring the net valid data of each branch to the corresponding receive buffer, the FPGA determines whether the net valid data of branch n has been received. If it has been received, the FPGA uploads the net valid data to the corresponding branch location in DDR memory via the AXI data transmission module, then updates the register for interaction with the CPU, and notifies the CPU via the AXI bus. This process continues until all 63 lines have received the net valid data. If the net valid data of branch n has not been received, the FPGA determines whether the net valid data of branch n++ has been received, and repeats the process of uploading the net valid data to the corresponding branch location in DDR memory, updating the register for interaction with the CPU, and notifying the CPU via the AXI bus.

[0045] Due to the characteristics of fiber optic differential protection, it is necessary to calculate the inflow and outflow currents of the same device. Therefore, the time of sending and receiving fiber optic differential data needs to be converted to a time coordinate system with the CPU as the reference. Thus, when sending fiber optic differential data messages to the peer protection devices on different lines, a relative time recording method is used to record the actual sending time of the fiber optic differential data messages. When receiving fiber optic differential data messages from the peer protection devices on different lines, a relative time recording method is used to record the actual receiving time of the fiber optic differential data messages.

[0046] When sending fiber optic differential data packets to the peer protection devices on different lines, a relative time recording method is used. Specifically, the CPU of the station protection device reads the sampling time T1_FPGA of the FPGA and the time it records its own current time T1_CPU. When the FPGA frames the fiber optic differential data according to the STM-1 communication interface protocol and sends the framed fiber optic differential data packets to the peer protection devices on different lines through the STM-1 communication interface, the CPU reads the data transmission time T2_FPGA of the FPGA. Based on T1_FPGA, T1_CPU, and T2_FPGA, the CPU can calculate the actual transmission time T2_CPU of the fiber optic differential data packets with the CPU as the reference. That is, with the CPU as the reference, the actual transmission time T2_CPU of the fiber optic differential data packets = T1_CPU + (T2_FPGA - T1_FPGA).

[0047] The CPU assembles T1_FPGA, T1_CPU, the required sampling data from the other side, the actual transmission time of the previous frame T2_CPU, the actual reception time of the previous frame T4_CPU from the other side, and their respective frame sequence numbers, and writes them into the buffer. The station relay protection device will transmit T1_CPU, T2_CPU, and T4_CPU, along with their corresponding message sequence numbers, to the other side device during the transmission of the next frame.

[0048] When receiving fiber optic differential data messages from the peer protection devices of different lines, a relative time recording method is adopted. Specifically, after the FPGA receives several frames of fiber optic differential data messages, it triggers a CPU interrupt of the station protection device. After the interrupt is triggered, the CPU reads the first internal relative time of the FPGA in real time and compares it with the CPU's running time. The FPGA parses the second internal relative time when receiving different messages. The CPU calculates the actual reception time of the fiber optic differential data based on the first internal relative time, the running time, and the second internal relative time.

[0049] Taking every four frames as an example, during reception, the FPGA triggers a CPU interrupt once every four frames of STM-1 messages. The STM-1 message frame length and baud rate are fixed, so the interrupt interval is fixed. When an interrupt occurs, the CPU records the first internal relative time T3_FPGA of the FPGA at the time of the interrupt and compares it with the CPU's running time T3_CPU. The FPGA parses the frame headers of the fiber optic longitudinal differential messages from different counterpart devices in the four frames and calculates the second internal relative time T4_FPGA of the FPGA corresponding to the arrival of the frame header based on the frame header position. The CPU can calculate the actual reception time T4_CPU of the data with the CPU as a reference based on T3_CPU, T3_FPGA, and T4_FPGA.

[0050] In this scheme, the master device remains unchanged, while the slave device is adjusted. The slave device can calculate the sampling time deviation between itself and the master device based on the above three times and the trapezoidal alignment algorithm, and adjust its own sampling time to align with the master device. The trapezoidal alignment algorithm is quite common and will not be elaborated here.

[0051] The FPGA incorporates an internal relative time counter, whose value is continuously monitored by the CPU to determine the FPGA's relative operating time. This internal FPGA relative time counter has a 32-bit width, and with a 100MHz FPGA main clock, the time for one toggle is approximately 42 seconds, far exceeding the transmission time of the optical longitudinal differential signal (within 15ms). When the CPU sends a message, it encapsulates the transmission tributary number and corresponding sequence number according to a predefined format. After transmission, the FPGA informs the CPU of the sequence number and transmission time via a register. Similarly, upon receiving data, the FPGA encapsulates the reception time and sequence number along with the received data and transmits them to the CPU according to the predefined format.

[0052] The present invention provides a fiber optic differential data transmission method for a station-area relay protection device. By integrating an STM-1 communication interface and an FPGA onto the station-area protection device, the communication interface can be directly connected to the station's telecommunications equipment and simultaneously perform fiber optic differential communication with multiple line-end protection devices, simplifying the wiring and making the implementation simple and reliable. On the other hand, by fully utilizing the real-time and parallel processing advantages of the FPGA, fiber optic differential communication between the station-area protection and the conventional protection of multiple lines can be realized, improving the speed, reliability, and accuracy of the station-area protection device in clearing line faults, making it simple and reliable.

[0053] An embodiment of a fiber optic longitudinal differential data transmission system for a station-area relay protection device: For an embodiment of the fiber optic longitudinal differential data transmission system for a station-area relay protection device provided by the present invention, please refer to the relevant description of the transmission system in the aforementioned embodiment of the fiber optic longitudinal differential data transmission method for a station-area relay protection device, which will not be repeated here.

[0054] The fiber optic longitudinal differential data transmission system for a station-area relay protection device provided in this embodiment of the invention can achieve the same beneficial effects as the aforementioned fiber optic longitudinal differential data transmission method for a station-area relay protection device, and will not be repeated here.

Claims

1. A method for optical fiber longitudinal differential data transmission in a station-area relay protection device, characterized in that, include: The STM-1 communication interface and FPGA are integrated into the station domain protection device; The station protection device transmits the optical fiber longitudinal differential data required by each line to the FPGA; the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol, and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface. The fiber optic differential data packets sent by the peer protection devices of different lines are transmitted to the FPGA through the STM-1 communication interface; the FPGA processes the received fiber optic differential data packets to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device.

2. The fiber optic longitudinal differential data transmission method for station-area relay protection devices according to claim 1, characterized in that, The STM-1 communication interface is connected to the SDH multiplexing access device via the SDH network. The SDH multiplexing access device is used to communicate with the peer protection devices of different lines. The station protection device informs the FPGA that it has fiber optic differential data to send by writing to the register; and detects whether the FPGA has received fiber optic differential data packets sent by the peer protection device of different lines by reading the register.

3. The fiber optic longitudinal differential data transmission method for station-area relay protection devices according to claim 1 or 2, characterized in that, When sending fiber optic longitudinal differential data messages to the peer protection devices of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic longitudinal differential data messages. When receiving fiber optic longitudinal differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic longitudinal differential data packets.

4. The fiber optic longitudinal differential data transmission method for station-area relay protection devices according to claim 3, characterized in that, When sending fiber optic differential data packets to the peer protection devices of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic differential data packets, including: The CPU of the station protection device reads the sampling time of the FPGA at this moment; When the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface, the CPU reads the data transmission time of the FPGA at this time. The CPU calculates the actual transmission time of the fiber longitudinal differential data packet with the CPU as a reference based on the deviation between the sampling time and the data transmission time. When receiving fiber optic differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic differential data packets, including: After the FPGA receives several frames of fiber longitudinal differential data messages, it triggers a CPU interrupt of the station domain protection device. After the interrupt is triggered, the CPU reads the first internal relative time of the FPGA in real time and compares it with the CPU's running time. The FPGA parses the second internal relative time when receiving different messages. The CPU calculates the actual reception time of the fiber longitudinal differential data based on the first internal relative time, the running time, and the second internal relative time.

5. The fiber optic longitudinal differential data transmission method for station-area relay protection devices according to claim 1 or 2, characterized in that, Also includes: The station protection device and the peer protection device of the different lines use the fiber optic differential universal trapezoidal algorithm for sampling alignment. The station protection device is fixed as the main unit, and the sampling time is not adjusted. The protection devices at the opposite end of different lines are slave devices, and they are adjusted and aligned according to the calculated deviation from the sampling time of the station protection device.

6. A fiber optic longitudinal differential data transmission system for a station-area relay protection device, characterized in that, include: The station domain protection device, the STM-1 communication interface integrated on the station domain protection device, and the FPGA; The station protection device transmits the optical fiber longitudinal differential data required by each line to the FPGA; the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol, and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface. The fiber optic differential data packets sent by the peer protection devices of different lines are transmitted to the FPGA after passing through the STM-1 communication interface. The FPGA processes the received fiber optic differential data packets to obtain the net valid data corresponding to each line, and then transmits the net valid data to the station protection device.

7. The fiber optic longitudinal differential data transmission system for station-area relay protection devices according to claim 6, characterized in that, Also includes: The STM-1 communication interface is also connected to an SDH multiplexing access device via an SDH network. The SDH multiplexing access device is used to communicate with the peer protection devices of different lines. The station domain protection device informs the FPGA that there is optical fiber longitudinal differential data to be sent by writing to the register. The FPGA is detected by reading registers to determine whether it has received fiber optic longitudinal differential data packets sent by the peer protection devices of different lines.

8. The fiber optic longitudinal differential data transmission system for station-area relay protection devices according to claim 6 or 7, characterized in that, When sending fiber optic longitudinal differential data messages to the peer protection devices of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic longitudinal differential data messages. When receiving fiber optic longitudinal differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic longitudinal differential data packets.

9. The fiber optic longitudinal differential data transmission system for station-area relay protection devices according to claim 8, characterized in that, When sending fiber optic differential data packets to the peer protection devices of different lines, a relative time recording method is used to record the actual transmission time of the fiber optic differential data packets, including: The CPU of the station protection device reads the sampling time of the FPGA at this moment; When the FPGA frames the optical fiber longitudinal differential data according to the STM-1 communication interface protocol and sends the framed optical fiber longitudinal differential data message to the peer protection device of different lines through the STM-1 communication interface, the CPU reads the data transmission time of the FPGA at this time. The CPU calculates the actual transmission time of the fiber longitudinal differential data packet with the CPU as a reference based on the deviation between the sampling time and the data transmission time. When receiving fiber optic differential data packets from the peer protection devices of different lines, a relative time recording method is used to record the actual reception time of the fiber optic differential data packets, including: After the FPGA receives several frames of fiber longitudinal differential data messages, it triggers a CPU interrupt of the station domain protection device. After the interrupt is triggered, the CPU reads the first internal relative time of the FPGA in real time and compares it with the CPU's running time. The FPGA parses the second internal relative time when receiving different messages. The CPU calculates the actual reception time of the fiber longitudinal differential data based on the first internal relative time, the running time, and the second internal relative time.

10. The fiber optic longitudinal differential data transmission system for station-area relay protection devices according to claim 6 or 7, characterized in that, Also includes: The station protection device and the peer protection device of the different lines use the fiber optic differential universal trapezoidal algorithm for sampling alignment. The station protection device is fixed as the main unit, and the sampling time is not adjusted. The protection devices at the opposite end of different lines are slave devices, and they are adjusted and aligned according to the calculated deviation from the sampling time of the station protection device.

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