Inter-station communication device and method for serial multi-terminal direct-current incomplete polar converter stations

Abstract

The invention relates to the technical field of direct current power transmission control, and discloses an inter-station communication device and method for serial multi-terminal direct current incomplete pole converter stations, and the device comprises a first pole control host module, a first digital interface selection module and a first optical communication maintenance interface module which are configured at a first pole in a first incomplete pole converter station; the second pole control host module, the second digital interface selection module and the second optical communication maintenance interface module are configured on a second pole in the first incomplete pole converter station; the third pole control host module, the third digital interface selection module and the third optical communication maintenance interface module are configured on the first pole in the second incomplete pole converter station; and the fourth pole control host module, the fourth digital interface selection module and the fourth optical communication maintenance interface module are configured on a second pole in the second incomplete pole converter station. According to the invention, high-capacity rapid communication between two incomplete pole converter station pole control hosts in a series multi-terminal extra-high voltage direct current system can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of DC power transmission control, and particularly to an inter-station communication device and method for a series multi-terminal DC incomplete pole converter station. Background Art

[0002] High-voltage DC power transmission technology has obvious advantages in long-distance and large-capacity power transmission due to its low loss and small land occupation. At present, UHV DC power transmission projects are developing rapidly, and point-to-point power transmission has formed a mature technical system. Multi-terminal high-voltage DC power transmission systems have also been widely used, but the application of series multi-terminal UHV DC is less.

[0003] The series multi-terminal UHV DC system has extremely high requirements for inter-station communication of DC pole control, which is significantly different from the inter-station communication of traditional two-terminal converter stations. The inter-station communication of traditional UHV DC systems only needs to transmit a small amount of signals, and 2M bandwidth communication using multiplexed optical fibers can be used. Existing DC control and protection inter-station communication methods are only applicable to 2M bandwidth communication and cannot meet the large-capacity and fast communication requirements of series multi-terminal UHV DC systems. At the same time, the key control communication between devices is crucial for the operation of the DC system. In traditional UHV DC systems, this type of communication is carried out within the station and can achieve high-speed direct connection communication through a fast LAN network, etc. However, in the series multi-terminal UHV DC system, the station equipment is dispersed to incomplete pole converter stations in different regions, resulting in the inapplicability of traditional in-station communication connection methods.

[0004] Therefore, it is necessary to redesign the inter-station communication structure of the pole control of the incomplete pole converter station to simultaneously meet the synchronization requirements, bandwidth requirements, and channel redundancy requirements. Summary of the Invention

[0005] The purpose of the present invention is to meet the inter-station control requirements of two incomplete pole converter stations in a series multi-terminal UHV DC system. To achieve the above purpose, the present invention provides an inter-station communication device and method for a series multi-terminal DC incomplete pole converter station.

[0006] In a first aspect, an embodiment of the present invention provides an inter-station communication device for a series multi-terminal DC incomplete pole converter station, which is applied to a series multi-terminal UHV DC system. The series multi-terminal UHV DC system includes a first incomplete pole converter station and a second incomplete pole converter station. The two incomplete pole converter stations are both at the sending end or both at the receiving end. Each incomplete pole converter station includes a first pole and a second pole. The inter-station communication device includes: A first pole control host module, a first digital interface selection module, and a first optical communication maintenance interface module that are configured in the first pole of the first incomplete pole converter station and are connected in sequence; The second pole control host module, the second digital interface selection module, and the second optical communication maintenance interface module, which are arranged in the second pole of the first incomplete pole converter station and are connected in sequence; The third pole control host module, the third digital interface selection module, and the third optical communication maintenance interface module, which are arranged in the first pole of the second incomplete pole converter station and are connected in sequence; The fourth pole control host module, the fourth digital interface selection module, and the fourth optical communication maintenance interface module, which are arranged in the second pole of the second incomplete pole converter station and are connected in sequence; Wherein, the first optical communication maintenance interface module is connected to the third optical communication maintenance interface module through a first optical fiber, and the second optical communication maintenance interface module is connected to the fourth optical communication maintenance interface module through a second optical fiber.

[0007] Preferably, each pole control host module includes a duty host and a standby host, and each pole control host module is configured to generate and send key control signals and pole control status signals to the same pole of the opposite incomplete pole converter station. Among them, the key control signals include pole current instructions, trigger angle instructions, and voltage balance control compensation signals, and the pole control status signals include host operation status, DC pole operation status, and pole control system fault level.

[0008] Preferably, each digital interface selection module includes a first digital interface selection unit and a second digital interface selection unit, and each digital interface selection module is configured to select an optimal signal source based on the pole control status signals sent by the same pole of the opposite incomplete pole converter station, and transmit the optimal signal source to the duty host and the standby host of the same pole of the local incomplete pole converter station simultaneously.

[0009] Preferably, the first digital interface selection unit and the second digital interface selection unit are connected to the duty host and the standby host of the same pole of the local incomplete pole converter station in a cross-connected manner.

[0010] Preferably, both the first optical fiber and the second optical fiber include a plurality of optical fiber communication links, and each optical communication maintenance interface module includes a first optical communication maintenance interface unit and a second optical communication maintenance interface unit.

[0011] Preferably, each optical communication maintenance interface module is configured to be connected to the optimal optical fiber communication link of the corresponding optical fiber based on a preset channel selection strategy. Among them, the preset channel selection strategy includes selecting the optimal optical fiber communication link based on the status monitoring data of each optical communication maintenance interface module on both sides of each optical fiber communication link, and the status monitoring data includes working mode, self-check data, and optical signal reception data.

[0012] Second aspect, embodiments of the present invention provide a method for inter-station communication of a series multi-terminal DC incomplete pole converter station, which is applied to the inter-station communication device of the series multi-terminal DC incomplete pole converter station as described above. The inter-station communication method includes: Generate first pole control system operation data through the first pole control host module, and send the first pole control system operation data to the first digital interface selection module, where the first pole control system operation data includes a first control instruction and a first operation state; Encrypt the first pole control system operation data through the first digital interface selection module to obtain first encrypted data, and transmit the first encrypted data to the first optical communication maintenance interface module; Send the first encrypted data to the third optical communication maintenance interface module through the first optical fiber by the first optical communication maintenance interface module; Transmit the first encrypted data to the third digital interface selection module through the third optical communication maintenance interface module; Decrypt the first encrypted data through the third digital interface selection module to obtain first decrypted data, and send the first decrypted data to the third pole control host module; Read and execute the first decrypted data through the third pole control host module.

[0013] Preferably, the inter-station communication method further includes: Generate second pole control system operation data through the second pole control host module, and send the second pole control system operation data to the second digital interface selection module, where the second pole control system operation data includes a second control instruction and a second operation state; Encrypt the second pole control system operation data through the second digital interface selection module to obtain second encrypted data, and transmit the second encrypted data to the second optical communication maintenance interface module; Send the second encrypted data to the fourth optical communication maintenance interface module through the second optical fiber by the second optical communication maintenance interface module; Transmit the second encrypted data to the fourth digital interface selection module through the fourth optical communication maintenance interface module; Decrypt the second encrypted data through the fourth digital interface selection module to obtain second decrypted data, and send the second decrypted data to the fourth pole control host module; Read and execute the second decrypted data through the fourth pole control host module.

[0014] Preferably, the inter-station communication method further includes: The third pole control host module generates the operation data of the third pole control system and sends the operation data of the third pole control system to the third digital interface selection module, where the operation data of the third pole control system includes a third control instruction and a third operation state; The third digital interface selection module encrypts the operation data of the third pole control system to obtain third encrypted data and transmits the third encrypted data to the third optical communication maintenance interface module; The third optical communication maintenance interface module sends the third encrypted data to the first optical communication maintenance interface module through a first optical fiber; The first optical communication maintenance interface module transmits the third encrypted data to the first digital interface selection module; The first digital interface selection module decrypts the third encrypted data to obtain third decrypted data and sends the third decrypted data to the first pole control host module; The first pole control host module reads and executes the third decrypted data.

[0015] Preferably, the inter-station communication method further includes: The fourth pole control host module generates the operation data of the fourth pole control system and sends the operation data of the fourth pole control system to the fourth digital interface selection module, where the operation data of the fourth pole control system includes a fourth control instruction and a fourth operation state; The fourth digital interface selection module encrypts the operation data of the fourth pole control system to obtain fourth encrypted data and transmits the fourth encrypted data to the fourth optical communication maintenance interface module; The fourth optical communication maintenance interface module sends the fourth encrypted data to the second optical communication maintenance interface module through a second optical fiber; The second optical communication maintenance interface module transmits the fourth encrypted data to the second digital interface selection module; The second digital interface selection module decrypts the fourth encrypted data to obtain fourth decrypted data and sends the fourth decrypted data to the second pole control host module; The second pole control host module reads and executes the fourth decrypted data.

[0016] Compared with the prior art, the beneficial effects of the inter-station communication device and method for a series multi-terminal DC incomplete pole converter station in an embodiment of the present invention are as follows: Each pole control host module, digital interface selection module, and optical communication maintenance interface module are orderly interconnected within the incomplete pole converter station, and a direct connection is established between stations through optical fibers, greatly reducing signal transmission delay, achieving high-speed synchronous transmission of various control signals and status information between different converter stations, and effectively ensuring the stable operation of the series multi-terminal UHV DC system; The optical fiber bandwidth resources are flexibly allocated according to actual communication requirements. This design avoids congestion during data transmission, provides sufficient bandwidth for the transmission of a large amount of key data such as pole current commands and trigger angle commands, and can meet the system's requirements for real-time performance and data volume; Each optical communication maintenance interface module dynamically selects the optimal optical fiber communication link according to the preset channel selection strategy by analyzing the working modes, self-check data, and optical signal reception data of the modules on both sides of the link. When a certain link fails, it can quickly switch to the standby link based on the status monitoring data to maintain stable communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the inter-station communication device in an embodiment of the present invention; Figure 2 is another schematic structural diagram of the inter-station communication device in an embodiment of the present invention; Figure 3 is a schematic flowchart of the inter-station communication method in an embodiment of the present invention; REFERENCE SIGNS: PCP1, the first pole control host module; PCP2, the second pole control host module; PCP3, the third pole control host module; PCP4, the fourth pole control host module; DIS1, the first digital interface selection module; DIS2, the second digital interface selection module; DIS3, the third digital interface selection module; DIS4, the fourth digital interface selection module; OMI1, the first optical communication maintenance interface module; OMI2, the second optical communication maintenance interface module; OMI3, the third optical communication maintenance interface module; OMI4, the fourth optical communication maintenance interface module; PCP1A, the A host of the first pole control host module; PCP1B, the B host of the first pole control host module; PCP2A, the A host of the second pole control host module; PCP2B, the B host of the second pole control host module; PCP3A, the A host of the third pole control host module; PCP3B, the B host of the third pole control host module; PCP4A, the A host of the fourth pole control host module; PCP4B, the B host of the fourth pole control host module; DIS1A, the first digital interface selection unit of the first digital interface selection module; DIS1B, the second digital interface selection unit of the first digital interface selection module; DIS2A, the first digital interface selection unit of the second digital interface selection module; DIS2B, the second digital interface selection unit of the second digital interface selection module; DIS3A, the first digital interface selection unit of the third digital interface selection module; DIS3B, the second digital interface selection unit of the third digital interface selection module; DIS4A, the first digital interface selection unit of the fourth digital interface selection module; DIS4B, the second digital interface selection unit of the fourth digital interface selection module; OMI1A, the first optical communication maintenance interface unit of the first optical communication maintenance interface module; OMI1B, the second optical communication maintenance interface unit of the first optical communication maintenance interface module; OMI2A, the first optical communication maintenance interface unit of the second optical communication maintenance interface module; OMI2B, the second optical communication maintenance interface unit of the second optical communication maintenance interface module; OMI3A, the first optical communication maintenance interface unit of the third optical communication maintenance interface module; OMI3B, the second optical communication maintenance interface unit of the third optical communication maintenance interface module; OMI4A, the first optical communication maintenance interface unit of the fourth optical communication maintenance interface module; OMI4B, the second optical communication maintenance interface unit of the fourth optical communication maintenance interface module; 11, the first optical fiber communication link; 12, the second optical fiber communication link; 13, the third optical fiber communication link; 14, the fourth optical fiber communication link; 21, the fifth optical fiber communication link; 22, the sixth optical fiber communication link; 23, the seventh optical fiber communication link; 24, the eighth optical fiber communication link. Detailed implementation mode

[0018] The specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "first" and "second" etc. used in the present invention are used to distinguish different objects, rather than to describe a specific order.

[0020] In the description of the present invention, it should be noted that unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In a UHVDC system, the same pole of the rectifier side or the inverter side is composed of a high-voltage converter and a low-voltage converter. For a series multi-terminal UHVDC system, the high-voltage converter and the low-voltage converter are respectively located in two different converter stations, and both of these two converter stations are incomplete-pole converter stations.

[0022] The series multi-terminal UHVDC system adopts a monopole structure or a bipolar structure, and generally a bipolar structure in engineering. For a series multi-terminal UHVDC system with a monopole structure, the converter station where the high-voltage converter is located only has the high-voltage converter, and the converter station where the low-voltage converter is located only has the low-voltage converter. For a series multi-terminal UHVDC system with a bipolar structure, each incomplete-pole converter station includes two poles, and each pole has one converter. That is to say, one incomplete-pole converter station has the high-voltage converter of each pole, and the other incomplete-pole converter station has the low-voltage converter of each pole.

[0023] The embodiment of the present invention provides an inter-station communication device for a series multi-terminal DC incomplete-pole converter station, which is applied to a series multi-terminal UHVDC system. The series multi-terminal UHVDC system includes three or more converter stations, including a first incomplete-pole converter station and a second incomplete-pole converter station. The two incomplete-pole converter stations are both at the sending end or both at the receiving end. Each incomplete-pole converter station includes a first pole and a second pole. It can be understood that in the UHVDC system, "pole" is an important concept, which represents the same pole of all converters constituting the rectifier side or the inverter side in the UHVDC system.

[0024] As Figure 1 shown, the inter-station communication device includes: A first pole control host module PCP1, a first digital interface selection module DIS1, and a first optical communication maintenance interface module OMI1 that are configured in the first pole of the first incomplete-pole converter station and are connected in sequence; The second pole control host module PCP2, the second digital interface selection module DIS2, and the second optical communication maintenance interface module OMI2, which are configured in the second pole of the first incomplete pole converter station and are connected in sequence; The third pole control host module PCP3, the third digital interface selection module DIS3, and the third optical communication maintenance interface module OMI3, which are configured in the first pole of the second incomplete pole converter station and are connected in sequence; The fourth pole control host module PCP4, the fourth digital interface selection module DIS4, and the fourth optical communication maintenance interface module OMI4, which are configured in the second pole of the second incomplete pole converter station and are connected in sequence.

[0025] The first digital interface selection module is respectively connected to the first pole control host module and the first optical communication maintenance interface module. The second digital interface selection module is respectively connected to the second pole control host module and the second optical communication maintenance interface module. The third digital interface selection module is respectively connected to the third pole control host module and the third optical communication maintenance interface module. The fourth digital interface selection module is respectively connected to the fourth pole control host module and the fourth optical communication maintenance interface module. The first optical communication maintenance interface module is connected to the third optical communication maintenance interface module through the first optical fiber 1, and the second optical communication maintenance interface module is connected to the fourth optical communication maintenance interface module through the second optical fiber 2.

[0026] Specifically, the DC control devices that need to communicate between the two incomplete pole converter stations are the pole control host modules of the first pole and the second pole respectively. Each pole control host module includes a duty host and a standby host. Each pole control host module is configured to generate and send key control signals and pole control status signals to the same pole of the opposite incomplete pole converter station. The key control signals include pole current commands, trigger angle commands, and voltage balance control compensation signals. The pole control status signals include host operating status, DC pole operating status, and pole control system fault levels. Further, each pole control host module is also configured to control the converter of the same pole of the local incomplete pole converter station and coordinate the control of the converters of the same pole of the two incomplete pole converter stations according to the pole current command.

[0027] Further, as Figure 2 shown, the first pole control host module includes host A PCP1A and host B PCP1B. The second pole control host module includes host A PCP2A and host B PCP2B. The third pole control host module includes host A PCP3A and host B PCP3B. The fourth pole control host module includes host A PCP4A and host B PCP4B. The two hosts of each pole control host module are in a redundant standby relationship with each other. At the same time, one of host A and host B is the duty host, and the other is the standby host.

[0028] Each pole control host module sends key control signals required to ensure the operation of the DC system, such as pole current commands, trigger angle commands, and voltage balance control compensation signals, to the other incomplete pole converter station in real time, as well as pole control status signals such as the host operation status, DC pole operation status, and pole control system fault level for information selection of the incomplete pole converter station. Each pole control host module in this embodiment has no less than two optical fiber interfaces, and the signals are packetized and sent through the Ethernet protocol.

[0029] Specifically, each digital interface selection module includes a first digital interface selection unit and a second digital interface selection unit. Each digital interface selection module is configured to select the optimal signal source based on the pole control status signals sent by the same pole of the opposite incomplete pole converter station, and transmit the optimal signal source to the duty host and standby host of the same pole of the local incomplete pole converter station simultaneously. The first digital interface selection unit and the second digital interface selection unit are connected to the duty host and standby host of the same pole of the local incomplete pole converter station in a cross-connection manner.

[0030] Further, as Figure 2 shown, the first digital interface selection module includes a first digital interface selection unit DIS1A and a second digital interface selection unit DIS1B, the second digital interface selection module includes a first digital interface selection unit DIS2A and a second digital interface selection unit DIS2B, the third digital interface selection module includes a first digital interface selection unit DIS3A and a second digital interface selection unit DIS3B, and the fourth digital interface selection module includes a first digital interface selection unit DIS4A and a second digital interface selection unit DIS4B.

[0031] Each digital interface selection module should have no less than two ports connected to the local incomplete pole converter station and no less than one port connected to the opposite incomplete pole converter station. The first digital interface selection unit and the second digital interface selection unit of each digital interface selection module are connected to the A host and B host of the corresponding pole control host module in a cross-connection manner through a 100M optical fiber or network cable on one side within the incomplete pole converter station. Each digital interface selection module is built-in with a logic selection program for selecting a better signal source from the received signal sources sent by the A host or B host of the opposite incomplete pole converter station according to the pole control status signals such as the host operation status, DC pole operation status, and pole control system fault level sent by the pole control host module of the opposite incomplete pole converter station, and transmitting it to the A host and B host of the local incomplete pole converter station simultaneously.

[0032] Specifically, both the first optical fiber and the second optical fiber include a number of optical fiber communication links. There should be no less than 4 optical fiber communication links between two incomplete pole converter stations. Each optical fiber communication link uses an independent optical fiber core. The routing of these optical fiber core communication links between the two incomplete pole converter stations does not need to be specifically defined. It can be integrated in different optical cables laid between the first incomplete pole converter station and the second incomplete pole converter station, or can be connected to the optical fiber distribution frame interface device or other communication devices of the existing optical communication network according to the construction situation of the communication channel, so as to lead the optical fiber through a detour path passing through other substations or communication nodes. Each optical communication maintenance interface module includes a first optical communication maintenance interface unit and a second optical communication maintenance interface unit. Each optical communication maintenance interface module is configured to connect to the optimal optical fiber communication link of the corresponding optical fiber based on a preset channel selection strategy. The preset channel selection strategy includes selecting the optimal optical fiber communication link based on the status monitoring data of each optical communication maintenance interface module on both sides of each optical fiber communication link. The status monitoring data includes the working mode, self-check data, and optical signal reception data.

[0033] Further, as Figure 2 shown, both the first optical fiber and the second optical fiber include 4 optical fiber communication links. The first optical fiber includes the first optical fiber communication link 11, the second optical fiber communication link 12, the third optical fiber communication link 13, and the fourth optical fiber communication link 14. The second optical fiber includes the fifth optical fiber communication link 21, the sixth optical fiber communication link 22, the seventh optical fiber communication link 23, and the eighth optical fiber communication link 24. The first optical communication maintenance interface module includes the first optical communication maintenance interface unit OMI1A and the second optical communication maintenance interface unit OMI1B. The second optical communication maintenance interface module includes the first optical communication maintenance interface unit OMI2A and the second optical communication maintenance interface unit OMI2B. The third optical communication maintenance interface module includes the first optical communication maintenance interface unit OMI3A and the second optical communication maintenance interface unit OMI3B. The fourth optical communication maintenance interface module includes the first optical communication maintenance interface unit OMI4A and the second optical communication maintenance interface unit OMI4B.

[0034] Each optical communication maintenance interface module should have no less than one port connected to the incomplete pole converter station on its own side and no less than two ports connected to the incomplete pole converter station on the opposite side. Each optical communication maintenance interface module is connected to the corresponding digital interface selection module through an optical fiber or network cable with a bandwidth of more than 100 Mbps on one side inside the incomplete pole converter station, and is extended and connected to different optical fiber communication links through a dedicated 100-Mbps optical fiber core on the outside of the incomplete pole converter station, and is connected to the corresponding optical communication maintenance interface module of the incomplete pole converter station on the opposite side through the optical fiber communication link. Each optical communication maintenance interface module is respectively connected to two or more different optical fiber communication links. Each optical fiber communication link is a 100-Mbps optical fiber.

[0035] The optical communication maintenance interface module integrates a preset channel selection strategy internally and is connected to only one of two or more communication links at the same time. The optical communication maintenance interface module has an optical channel detection function and a switching function, and the switching function is divided into automatic switching and manual switching. The validity of the optical fiber channel is detected by sending a set pulsed optical signal in real time. When the communication is invalid, it indicates a communication failure in this link. The optical communication maintenance interface module sends a channel failure signal to the digital interface selection module and automatically switches the communication link. During the maintenance of the communication link, switching can be performed by manually setting an optical communication maintenance interface module to the "maintenance state", etc. At this time, the optical communication maintenance interface module switches during the gap between the transmissions of two communication packets using the Ethernet protocol for detection.

[0036] The above-mentioned switching functions of automatic switching and manual switching are implemented through the preset channel selection strategy of the optical communication maintenance interface module, that is, the optimal communication link is selected according to the operating / maintenance state, normal self-check, normal pulsed optical signal reception, etc. of the optical communication maintenance interface modules on both sides of the optical communication channel. In this embodiment, if both optical communication maintenance interface modules on both sides of the optical communication channel are in the operating state, with normal self-check, normal pulsed optical signal reception, and the optical communication channel is the preferred channel, then this optical communication channel is selected as the optimal optical fiber communication link.

[0037] In the embodiment of the present invention, a series multi-terminal DC incomplete pole converter station inter-station communication device is provided. Each pole control host module, digital interface selection module, and optical communication maintenance interface module are interconnected in an orderly manner within the incomplete pole converter station and are directly connected between stations through optical fibers, greatly reducing the signal transmission delay, achieving high-speed synchronous transmission of various control signals and status information between different converter stations, and effectively ensuring the stable operation of the series multi-terminal UHV DC system; the optical fiber bandwidth resources are flexibly allocated according to the actual communication requirements. This design avoids congestion during data transmission and provides sufficient bandwidth for the transmission of a large amount of key data such as pole current commands and trigger angle commands, and can meet the requirements of the system for real-time performance and data volume; each optical communication maintenance interface module dynamically selects the optimal optical fiber communication link according to the preset channel selection strategy by analyzing the working modes, self-check data, and optical signal reception data of the modules on both sides of the link. When a certain link fails, it can quickly switch to the standby link based on the status monitoring data to maintain stable communication.

[0038] The embodiment of the present invention provides a series multi-terminal DC incomplete pole converter station inter-station communication method, which is applied to the series multi-terminal DC incomplete pole converter station inter-station communication device as described above.

[0039] As Figure 3 shown, the inter-station communication method includes the steps: S1. The first pole control host module generates the operation data of the first pole control system and sends the operation data of the first pole control system to the first digital interface selection module; The duty host and the standby host of the first pole control host module respectively perform closed-loop regulation control according to the DC current of this station, the DC port voltage of this station, the operation of each system of the series multi-terminal DC, etc., according to the set control objectives, and generate the operation data of the first pole control system required for various DC operations, namely the first control instruction and the first operation state.

[0040] These control instructions and operation states include four major parts. One is the instruction for adjusting the first pole converter of each converter station, such as the control mode and the pole current instruction; the second is the instruction for adjusting the first pole converter of this converter station, such as the trigger angle instruction and the trigger pulse instruction; the third is the voltage balance control compensation signal for additional control between the poles of multiple incomplete pole converter stations and instructions such as the converter control mode; the fourth is the state signals such as the converter operation state, the host duty state (duty state, non-duty state, maintenance state, etc.) and the communication health state. The duty host and the standby host of the first pole control host module respectively package the first control instruction and the first operation state generated by this host through the Ethernet protocol. The two hosts respectively send the communication packets to the first digital interface selection unit and the second digital interface selection unit of the first digital interface selection module.

[0041] S2. The first digital interface selection module encrypts the operation data of the first pole control system to obtain the first encrypted data and transmits the first encrypted data to the first optical communication maintenance interface module; The first digital interface selection unit and the second digital interface selection unit of the first digital interface selection module respectively receive the communication packets from the two hosts of the first pole control host module, add the self-check normal information of the first data interface selection module, and encrypt the communication packets. The first digital interface selection unit sends the processed communication packet to the first optical communication maintenance interface unit of the first optical communication maintenance interface module, and the second digital interface selection unit sends the processed communication packet to the second optical communication maintenance interface unit of the first optical communication maintenance interface module.

[0042] S3. The first optical communication maintenance interface module sends the first encrypted data to the third optical communication maintenance interface module through the first optical fiber; The first optical communication maintenance interface unit of the first optical communication maintenance interface module respectively sends communication packets to the first optical communication maintenance interface unit of the third optical communication maintenance interface module through the first optical fiber communication link and the second optical fiber communication link. The second optical communication maintenance interface unit of the first optical communication maintenance interface module respectively sends communication packets to the second optical communication maintenance interface unit of the third optical communication maintenance interface module through the third optical fiber communication link and the fourth optical fiber communication link.

[0043] The first optical communication maintenance interface module continuously and respectively sends and receives pulsed optical signals to and from the third optical communication maintenance interface module through the first optical fiber communication link and the second optical fiber communication link according to the setting, receives normal / anomalous pulsed signals to judge the connection state of the optical fiber path, and sends the normal operation signal of this module. When any one of the optical communication maintenance interface modules fails to continuously detect the pulsed optical signal of a certain optical fiber path, it indicates that the optical fiber path is faulty. After receiving the signal, the third optical communication maintenance interface module selects a better path and sends it to the third digital interface selection module corresponding to the second incomplete converter station. The selection and determination logic includes: 1) When any one of the optical communication maintenance interface modules on either side of a certain channel is in the "maintenance" state, this channel is not selected; 2) When any one of the optical communication maintenance interface modules on either side of a certain channel has a self-check anomaly, this channel is not selected; 3) When the receiving end of a certain channel fails to receive the correct pulsed optical signal of the optical communication interface, this channel is not selected; 4) When multiple channels are available, the preset preferred channel is preferentially used.

[0044] The first optical communication maintenance interface module can select to configure or not configure an optical power amplifier at the sending end according to the length of the transmission optical fiber.

[0045] S4. Transmit the first encrypted data to the third digital interface selection module through the third optical communication maintenance interface module; The first optical communication maintenance interface unit of the third optical communication maintenance interface module receives the information of the communication channel selected in step S3 and sends it to the first digital interface selection unit of the third digital interface selection module; the second optical communication maintenance interface unit of the third optical communication maintenance interface module receives the information of the communication channel selected in step S3 and sends it to the second digital interface selection unit of the third digital interface selection module.

[0046] S5. Decrypt the first encrypted data through the third digital interface selection module to obtain the first decrypted data, and send the first decrypted data to the third pole control host module; The first digital interface selection unit of the third digital interface selection module receives the information from the first optical communication maintenance interface unit of the third optical communication maintenance interface module in step S4, decrypts the communication packet, and selects the information of the duty host in the first pole control host module from the information parsed from the first pole control host module, and forwards it to both the duty host and the standby host of the third pole control host module at the same time.

[0047] S6. Read and execute the first decrypted data through the third pole control host module.

[0048] The duty host and standby host of the third-pole control host module respectively receive information from the duty host in the first-pole control host module. The duty host and standby host of the third-pole control host module respectively read the control mode, pole current command, voltage balance control compensation signal, etc. in the information, participate in the control of the first-pole converter of the second incomplete-pole converter station, and form trigger angle commands, trigger pulse commands, etc. required for the regulation of the first-pole converter of the second incomplete-pole converter station, so as to maintain the stable and coordinated operation of the incomplete-pole converter station in the series multi-terminal UHVDC system.

[0049] It can be understood that steps S1 to S6 reflect the inter-station communication process in which the first-pole control host module sends information to the third-pole control host module.

[0050] Furthermore, the inter-station communication method further includes the steps of: 1) Generate the operation data of the second-pole control system through the second-pole control host module, and send the operation data of the second-pole control system to the second digital interface selection module; The operation data of the second-pole control system includes the second control command and the second operation state.

[0051] 2) Encrypt the operation data of the second-pole control system through the second digital interface selection module to obtain the second encrypted data, and transmit the second encrypted data to the second optical communication maintenance interface module; 3) Send the second encrypted data through the second optical communication maintenance interface module to the fourth optical communication maintenance interface module through the second optical fiber; 4) Transmit the second encrypted data to the fourth digital interface selection module through the fourth optical communication maintenance interface module; 5) Decrypt the second encrypted data through the fourth digital interface selection module to obtain the second decrypted data, and send the second decrypted data to the fourth-pole control host module; 6) Read and execute the second decrypted data through the fourth-pole control host module.

[0052] It can be understood that steps 1) to 6) reflect the inter-station communication process in which the second-pole control host module sends information to the fourth-pole control host module. For the specific limitations, refer to the limitations of the inter-station communication process in which the first-pole control host module sends information to the third-pole control host module (steps S1 to S6) in the above text. The two have the same functions and effects and will not be elaborated here.

[0053] Furthermore, the inter-station communication method further includes the steps of: 1) Generate the operation data of the third-pole control system through the third-pole control host module, and send the operation data of the third-pole control system to the third digital interface selection module; The operation data of the third pole control system includes the third control instruction and the third operation status.

[0054] 2) Encrypt the operation data of the third pole control system through the third digital interface selection module to obtain the third encrypted data, and transmit the third encrypted data to the third optical communication maintenance interface module; 3) Send the third encrypted data to the first optical communication maintenance interface module through the first optical fiber via the third optical communication maintenance interface module; 4) Transmit the third encrypted data to the first digital interface selection module through the first optical communication maintenance interface module; 5) Decrypt the third encrypted data through the first digital interface selection module to obtain the third decrypted data, and send the third decrypted data to the first pole control host module; 6) Read and execute the third decrypted data through the first pole control host module.

[0055] It can be understood that steps 1) to 6) reflect the inter-station communication process in which the third pole control host module sends information to the first pole control host module. For specific limitations, refer to the limitations of the inter-station communication process in which the first pole control host module sends information to the third pole control host module (steps S1 to S6) in the above text. The two have the same functions and effects and will not be elaborated here.

[0056] Furthermore, the inter-station communication method further includes the steps: 1) Generate the operation data of the fourth pole control system through the fourth pole control host module, and send the operation data of the fourth pole control system to the fourth digital interface selection module; The operation data of the fourth pole control system includes the fourth control instruction and the fourth operation status.

[0057] 2) Encrypt the operation data of the fourth pole control system through the fourth digital interface selection module to obtain the fourth encrypted data, and transmit the fourth encrypted data to the fourth optical communication maintenance interface module; 3) Send the fourth encrypted data to the second optical communication maintenance interface module through the second optical fiber via the fourth optical communication maintenance interface module; 4) Transmit the fourth encrypted data to the second digital interface selection module through the second optical communication maintenance interface module; 5) Decrypt the fourth encrypted data through the second digital interface selection module to obtain the fourth decrypted data, and send the fourth decrypted data to the second pole control host module; 6) Read and execute the fourth decrypted data through the second pole control host module.

[0058] It can be understood that the inter-station communication process in which the fourth-pole control host module sends information to the second-pole control host module as reflected in steps 1) to 6) is specifically defined by referring to the inter-station communication process (steps S1 to S6) in which the first-pole control host module sends information to the third-pole control host module in the foregoing text. The two have the same functions and effects and will not be elaborated here.

[0059] In summary, for the inter-station communication device and method of an in-complete pole converter station in a series multi-terminal HVDC system according to an embodiment of the present invention, each pole control host module, digital interface selection module, and optical communication maintenance interface module are orderly interconnected within the in-complete pole converter station and directly connected between stations through optical fibers, greatly reducing signal transmission delay, achieving high-speed synchronous transmission of various control signals and status information between different converter stations, and effectively ensuring the stable operation of the series multi-terminal UHVDC system; the optical fiber bandwidth resources are flexibly allocated according to actual communication requirements, and this design avoids congestion phenomena during data transmission, provides sufficient bandwidth for the transmission of a large amount of key data such as pole current commands and trigger angle commands, and can meet the requirements of the system for real-time performance and data volume; each optical communication maintenance interface module dynamically selects the optimal optical fiber communication link by analyzing the working modes, self-check data, and optical signal reception data of the modules on both sides of the link according to the preset channel selection strategy. When a certain link fails, it can quickly switch to the standby link based on the status monitoring data to maintain communication stability.

[0060] Each embodiment in this specification is described in a progressive manner. For the parts that are the same or similar in each embodiment, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. It should be noted that the various technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0061] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and replacements can still be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. A communication device between series multi-terminal DC incomplete pole converter stations, which is applied to a series multi-terminal UHV DC system. The series multi-terminal UHV DC system includes a first incomplete pole converter station and a second incomplete pole converter station. The two incomplete pole converter stations are both at the sending end or both at the receiving end. Each of the incomplete pole converter stations includes a first pole and a second pole. It is characterized in that, The inter-station communication device includes: A first pole control host module, a first digital interface selection module, and a first optical communication maintenance interface module, which are arranged in the first pole of the first incomplete pole converter station and are connected in sequence; A second pole control host module, a second digital interface selection module, and a second optical communication maintenance interface module, which are arranged in the second pole of the first incomplete pole converter station and are connected in sequence; A third pole control host module, a third digital interface selection module, and a third optical communication maintenance interface module, which are arranged in the first pole of the second incomplete pole converter station and are connected in sequence; A fourth pole control host module, a fourth digital interface selection module, and a fourth optical communication maintenance interface module, which are arranged in the second pole of the second incomplete pole converter station and are connected in sequence; Wherein, the first optical communication maintenance interface module is connected to the third optical communication maintenance interface module through a first optical fiber, and the second optical communication maintenance interface module is connected to the fourth optical communication maintenance interface module through a second optical fiber.

2. The inter-station communication device according to claim 1, wherein Each pole control host module includes a duty host and a standby host. Each pole control host module is configured to generate and send key control signals and pole control status signals to the same pole of the opposite incomplete pole converter station. Among them, the key control signals include pole current instructions, trigger angle instructions, and voltage balance control compensation signals, and the pole control status signals include host operating status, DC pole operating status, and pole control system fault level.

3. The inter-station communication device according to claim 2, wherein Each digital interface selection module includes a first digital interface selection unit and a second digital interface selection unit. Each digital interface selection module is configured to select an optimal signal source based on the pole control status signals sent by the same pole of the opposite incomplete pole converter station, and transmit the optimal signal source to the duty host and standby host of the same pole of the local incomplete pole converter station at the same time.

4. The inter-station communication device according to claim 3, characterized in that The first digital interface selection unit and the second digital interface selection unit are connected to the duty host and standby host of the same pole of the local incomplete pole converter station in a cross-connected manner.

5. The inter-station communication device according to claim 1, wherein Both the first optical fiber and the second optical fiber include a plurality of optical fiber communication links. Each optical communication maintenance interface module includes a first optical communication maintenance interface unit and a second optical communication maintenance interface unit.

6. The inter-station communication device according to claim 5, wherein Each optical communication maintenance interface module is configured to connect to the optimal optical fiber communication link of the corresponding optical fiber based on a preset channel selection strategy. The preset channel selection strategy includes selecting the optimal optical fiber communication link based on the status monitoring data of each optical communication maintenance interface module on both sides of each optical fiber communication link. The status monitoring data includes working mode, self-check data, and optical signal reception data.

7. A method for inter-station communication of a series multi-terminal DC incomplete pole converter station, applied to the inter-station communication device of the series multi-terminal DC incomplete pole converter station according to any one of claims 1 to 6, characterized in that, The inter-station communication method includes: Generating first pole control system operation data through the first pole control host module, and sending the first pole control system operation data to the first digital interface selection module, where the first pole control system operation data includes a first control instruction and a first operation status; Encrypting the first pole control system operation data through the first digital interface selection module to obtain first encrypted data, and transmitting the first encrypted data to the first optical communication maintenance interface module; Send the first encrypted data to the third optical communication maintenance interface module through the first optical communication maintenance interface module via the first optical fiber; Transmit the first encrypted data to the third digital interface selection module through the third optical communication maintenance interface module; Decrypt the first encrypted data through the third digital interface selection module to obtain the first decrypted data, and send the first decrypted data to the third-stage control host module; Read and execute the first decrypted data through the third-stage control host module.

8. The inter-station communication method according to claim 7, wherein The inter-station communication method further includes: Generate second-stage control system operation data through the second-stage control host module, and send the second-stage control system operation data to the second digital interface selection module, where the second-stage control system operation data includes a second control instruction and a second operation status; Encrypt the second-stage control system operation data through the second digital interface selection module to obtain second encrypted data, and transmit the second encrypted data to the second optical communication maintenance interface module; Send the second encrypted data to the fourth optical communication maintenance interface module through the second optical communication maintenance interface module via the second optical fiber; Transmit the second encrypted data to the fourth digital interface selection module through the fourth optical communication maintenance interface module; Decrypt the second encrypted data through the fourth digital interface selection module to obtain second decrypted data, and send the second decrypted data to the fourth-stage control host module; Read and execute the second decrypted data through the fourth-stage control host module.

9. The inter-station communication method according to claim 7, characterized in that, The inter-station communication method further includes: Generate third-stage control system operation data through the third-stage control host module, and send the third-stage control system operation data to the third digital interface selection module, where the third-stage control system operation data includes a third control instruction and a third operation status; Encrypt the third-stage control system operation data through the third digital interface selection module to obtain third encrypted data, and transmit the third encrypted data to the third optical communication maintenance interface module; Send the third encrypted data to the first optical communication maintenance interface module through the third optical communication maintenance interface module via the first optical fiber; Transmit the third encrypted data to the first digital interface selection module through the first optical communication maintenance interface module; Decrypt the third encrypted data through the first digital interface selection module to obtain third decrypted data, and send the third decrypted data to the first-stage control host module; Read and execute the third decrypted data through the first-stage control host module.

10. The inter-station communication method according to claim 7, characterized in that, The inter-station communication method further includes: Generate fourth-stage control system operation data through the fourth-stage control host module, and send the fourth-stage control system operation data to the fourth digital interface selection module, where the fourth-stage control system operation data includes a fourth control instruction and a fourth operation status; Encrypt the fourth-stage control system operation data through the fourth digital interface selection module to obtain fourth encrypted data, and transmit the fourth encrypted data to the fourth optical communication maintenance interface module; Send the fourth encrypted data to the second optical communication maintenance interface module through the fourth optical communication maintenance interface module via the second optical fiber; Transmit the fourth encrypted data to the second digital interface selection module through the second optical communication maintenance interface module; Decrypt the fourth encrypted data through the second digital interface selection module to obtain the fourth decrypted data, and send the fourth decrypted data to the second-stage control host module; Read and execute the fourth decrypted data through the second-stage control host module.

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