Inter-station communication device and method for series multi-terminal DC incomplete pole converter stations

Abstract

The present invention relates to the field of direct current (DC) transmission control technology, and discloses a device and method for inter-station communication in a series multi-terminal DC incomplete pole converter station. The device comprises: a first pole control host module, a first digital interface selection module, and a first optical communication maintenance interface module, configured at the first pole of a first incomplete pole converter station; a second pole control host module, a second digital interface selection module, and a second optical communication maintenance interface module, configured at the second pole of the first incomplete pole converter station; a third pole control host module, a third digital interface selection module, and a third optical communication maintenance interface module, configured at the first pole of the second incomplete pole converter station; and a fourth pole control host module, a fourth digital interface selection module, and a fourth optical communication maintenance interface module, configured at the second pole of the second incomplete pole converter station. The present invention can achieve high-capacity and rapid communication between pole control hosts of two incomplete pole converter stations in a series multi-terminal ultra-high voltage DC system.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current (DC) transmission control, and in particular to an inter-station communication device and method for series multi-terminal DC incomplete pole converter stations. Background Art

[0002] High-voltage direct current (HVDC) transmission technology, with its advantages of low losses and minimal footprint, offers significant advantages in long-distance, high-capacity power transmission. Currently, UHVDC transmission projects are developing rapidly, with a mature technical system for point-to-point power transmission and widespread deployment of multi-terminal HVDC systems. However, series multi-terminal UHVDC transmission is less widely used.

[0003] Series multi-terminal UHVDC systems place extremely high demands on inter-station communication for DC pole control, which differs significantly from the inter-station communication of traditional two-terminal converter stations. Traditional UHVDC system inter-station communication only requires the transmission of a small amount of signals, which can be achieved using 2M bandwidth communication using multiplexed optical fibers. Existing DC control and protection inter-station communication methods are also only suitable for 2M bandwidth communication, which cannot meet the large-capacity and fast communication requirements of series multi-terminal UHVDC systems. At the same time, critical control communication between devices is crucial to the operation of the DC system. In traditional UHVDC systems, this type of communication is carried out within the station, and high-speed direct communication can be achieved through fast LAN networks. However, series multi-terminal UHVDC systems disperse the in-station equipment to incomplete pole converter stations in different regions, making the traditional in-station communication connection method no longer applicable.

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

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

[0006] In a first aspect, an embodiment of the present invention provides an inter-station communication device for a series multi-terminal direct current incomplete pole converter station, which is applied to a series multi-terminal ultra-high voltage direct current system. The series multi-terminal ultra-high voltage direct current system includes a first incomplete pole converter station and a second incomplete pole converter station. The two incomplete pole converter stations are located at the same sending end or the same receiving end. Each of the incomplete pole converter stations includes a first pole and a second pole. The inter-station communication device includes:

[0007] A first pole control host module, a first digital interface selection module, and a first optical communication maintenance interface module are configured at the first pole in the first incomplete pole converter station and are connected in sequence;

[0008] A second pole control host module, a second digital interface selection module, and a second optical communication maintenance interface module are configured at the second pole in the first incomplete pole converter station and are connected in sequence;

[0009] A third pole control host module, a third digital interface selection module, and a third optical communication maintenance interface module are configured at the first pole in the second incomplete pole converter station and are connected in sequence;

[0010] A fourth pole control host module, a fourth digital interface selection module, and a fourth optical communication maintenance interface module are configured at the second pole in the second incomplete pole converter station and are connected in sequence;

[0011] The first optical communication maintenance interface module is connected to the third optical communication maintenance interface module via a first optical fiber, and the second optical communication maintenance interface module is connected to the fourth optical communication maintenance interface module via a second optical fiber.

[0012] Preferably, each pole control host module includes a duty host and a standby host, and each of the pole control host modules 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, wherein 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.

[0013] Preferably, each digital interface selection module includes a first digital interface selection unit and a second digital interface selection unit, and each of the digital interface selection modules is configured to select the optimal signal source based on the pole control state signal sent from the same pole of the incomplete pole converter station on the opposite side, and simultaneously transmit the optimal signal source to the on-duty host and the standby host of the same pole of the incomplete pole converter station on this side.

[0014] Preferably, the first digital interface selection unit and the second digital interface selection unit are connected to the on-duty host and the standby host of the same pole of the incomplete pole converter station on this side in a cross-connection manner.

[0015] Preferably, the first optical fiber and the second optical fiber each 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.

[0016] Preferably, each of the optical communication maintenance interface modules is configured to be connected to the optimal optical fiber communication link of the corresponding optical fiber based on a preset channel selection strategy, wherein the preset channel selection strategy includes selecting the optimal optical fiber communication link based on the status monitoring data of each of the optical communication maintenance interface modules on both sides of each optical fiber communication link, and the status monitoring data includes the working mode, self-test data and optical signal reception data.

[0017] In a second aspect, an embodiment of the present invention provides a method for inter-station communication in a series multi-terminal DC incomplete pole converter station, which is applied to the inter-station communication device for a series multi-terminal DC incomplete pole converter station as described above. The inter-station communication method includes:

[0018] 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, wherein the first pole control system operation data includes a first control instruction and a first operation state;

[0019] 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;

[0020] Sending the first encrypted data to the third optical communication maintenance interface module through the first optical fiber via the first optical communication maintenance interface module;

[0021] transmitting the first encrypted data to a third digital interface selection module via the third optical communication maintenance interface module;

[0022] decrypting the first encrypted data to obtain first decrypted data through the third digital interface selection module, and sending the first decrypted data to the third control host module;

[0023] The first decrypted data is read and executed by the third-party control host module.

[0024] Preferably, the inter-station communication method further includes:

[0025] 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, wherein the second pole control system operation data includes a second control instruction and a second operation state;

[0026] Encrypting the second pole control system operation data through the second digital interface selection module to obtain second encrypted data, and transmitting the second encrypted data to the second optical communication maintenance interface module;

[0027] sending the second encrypted data to the fourth optical communication maintenance interface module through the second optical fiber via the second optical communication maintenance interface module;

[0028] transmitting the second encrypted data to a fourth digital interface selection module via the fourth optical communication maintenance interface module;

[0029] decrypting the second encrypted data to obtain second decrypted data through the fourth digital interface selection module, and sending the second decrypted data to the fourth control host module;

[0030] The fourth pole controls the host module to read and execute the second decrypted data.

[0031] Preferably, the inter-station communication method further includes:

[0032] Generate third pole control system operation data through the third pole control host module, and send the third pole control system operation data to the third digital interface selection module, wherein the third pole control system operation data includes a third control instruction and a third operation state;

[0033] Encrypting the third pole control system operation data through the third digital interface selection module to obtain third encrypted data, and transmitting the third encrypted data to the third optical communication maintenance interface module;

[0034] Sending 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;

[0035] Transmitting the third encrypted data to the first digital interface selection module through the first optical communication maintenance interface module;

[0036] decrypting the third encrypted data to obtain third decrypted data through the first digital interface selection module, and sending the third decrypted data to the first pole control host module;

[0037] The host module is controlled by the first stage to read and execute the third decrypted data.

[0038] Preferably, the inter-station communication method further includes:

[0039] Generate fourth pole control system operation data through the fourth pole control host module, and send the fourth pole control system operation data to the fourth digital interface selection module, wherein the fourth pole control system operation data includes a fourth control instruction and a fourth operation state;

[0040] Encrypting the fourth pole control system operation data through the fourth digital interface selection module to obtain fourth encrypted data, and transmitting the fourth encrypted data to the fourth optical communication maintenance interface module;

[0041] sending 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;

[0042] transmitting the fourth encrypted data to the second digital interface selection module through the second optical communication maintenance interface module;

[0043] decrypting the fourth encrypted data to obtain fourth decrypted data through the second digital interface selection module, and sending the fourth decrypted data to the second pole control host module;

[0044] The host module is controlled by the second stage to read and execute the fourth decrypted data.

[0045] Compared with the prior art, the inter-station communication device and method for a series multi-terminal DC incomplete pole converter station according to the embodiment of the present invention have the following beneficial effects: the 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 a direct connection is established between the stations through optical fiber, which greatly reduces the signal transmission delay and realizes high-speed synchronous transmission of various control signals and status information between different converter stations, effectively ensuring the stable operation of the series multi-terminal ultra-high voltage DC system; the optical fiber bandwidth resources are flexibly allocated according to actual communication needs. 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 instructions and trigger angle instructions, which 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 a preset channel selection strategy by analyzing the working mode, self-test data and optical signal reception data of the modules on both sides of the link. When a link fails, it can quickly switch to the backup link based on the status monitoring data to maintain communication stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic structural diagram of an inter-station communication device according to an embodiment of the present invention;

[0047] Figure 2 is another structural diagram of the inter-station communication device according to an embodiment of the present invention;

[0048] Figure 3 1 is a flow chart of an inter-station communication method according to an embodiment of the present invention;

[0049] Reference numerals:

[0050] PCP1, first pole control host module; PCP2, second pole control host module; PCP3, third pole control host module; PCP4, fourth pole control host module; DIS1, first digital interface selection module; DIS2, second digital interface selection module; DIS3, third digital interface selection module; DIS4, fourth digital interface selection module; OMI1, first optical communication maintenance interface module; OMI2, second optical communication maintenance interface module; OMI3, third optical communication maintenance interface module; OMI4, fourth optical communication maintenance interface module; PCP1A, A host of the first pole control host module; PCP1B, B host; PCP2A, A host of the second-pole control host module; PCP2B, B host of the second-pole control host module; PCP3A, A host of the third-pole control host module; PCP3B, B host of the third-pole control host module; PCP4A, A host of the fourth-pole control host module; PCP4B, 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 Digital interface selection unit; 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 module The second optical communication maintenance interface unit; 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 DESCRIPTION

[0051] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" etc. are used in the present invention to distinguish different objects rather than to describe a specific order.

[0053] In describing the present invention, it should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those 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. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0054] In a UHVDC system, the same pole, forming the rectifier or inverter side, consists of a high-voltage converter and a low-voltage converter. For a series multi-terminal UHVDC system, the high-voltage and low-voltage converters are located in two different converter stations, both of which are incomplete-pole converter stations.

[0055] Series multi-terminal UHVDC systems use either a unipolar or bipolar structure, with bipolar structures generally used in engineering. For unipolar series multi-terminal UHVDC systems, the converter station where the high-voltage converter is located only has high-voltage converters, and the converter station where the low-voltage converter is located only has low-voltage converters. For bipolar series multi-terminal UHVDC systems, each incomplete-pole converter station includes two poles, with one converter for each pole. In other words, one incomplete-pole converter station has a high-voltage converter for each pole, while the other incomplete-pole converter station has a low-voltage converter for each pole.

[0056] An embodiment of the present invention provides an inter-station communication device for a series multi-terminal direct current (DC) incomplete pole converter station, which is applied to a series multi-terminal ultra-high voltage DC (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 located at either the sending end or the receiving end, and each incomplete pole converter station includes a first pole and a second pole. It is understood that in an UHVDC system, "pole" is an important concept, representing the same pole that constitutes all converters on the rectifier or inverter side of the UHVDC system.

[0057] like Figure 1 As shown, the inter-station communication device includes:

[0058] A first pole control host module PCP1, a first digital interface selection module DIS1 and a first optical communication maintenance interface module OMI1 are configured in the first pole of the first incomplete pole converter station and are connected in sequence;

[0059] A second pole control host module PCP2, a second digital interface selection module DIS2, and a second optical communication maintenance interface module OMI2 are configured in the second pole of the first incomplete pole converter station and are connected in sequence;

[0060] A third pole control host module PCP3, a third digital interface selection module DIS3 and a third optical communication maintenance interface module OMI3 are configured in the first pole of the second incomplete pole converter station and are connected in sequence;

[0061] The fourth pole control host module PCP4, the fourth digital interface selection module DIS4 and the fourth optical communication maintenance interface module OMI4 are configured in the second pole of the second incomplete pole converter station and are connected in sequence.

[0062] 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.

[0063] Specifically, the DC control devices required to communicate between the two incomplete pole converter stations are the pole control host modules of the first and second poles, respectively. Each pole control host module includes a duty host and a standby host. Each pole control host module is configured to generate and transmit key control signals and pole control status signals to the same pole of the opposite incomplete pole converter station. Key control signals include pole current commands, firing angle commands, and voltage balance control compensation signals. Pole control status signals include host operating status, DC pole operating status, and pole control system fault level. Furthermore, each pole control host module is also configured to control the converters on the same pole of the incomplete pole converter station on its side and coordinate control of the converters on the same pole of the two incomplete pole converter stations based on the pole current commands.

[0064] Further, if Figure 2As shown, the first-stage control host module includes host A PCP1A and host B PCP1B, the second-stage control host module includes host A PCP2A and host B PCP2B, the third-stage control host module includes host A PCP3A and host B PCP3B, and the fourth-stage control host module includes host A PCP4A and host B PCP4B. The two hosts in each stage of the control host module serve as redundant backup hosts. At any given time, one of hosts A and B is the active host, while the other is the backup host.

[0065] Each pole control host module transmits key control signals required to ensure DC system operation, such as pole current commands, firing angle commands, and voltage balance control compensation signals, to the incomplete pole converter station in real time. These signals also include pole control status signals such as host operating status, DC pole operating status, and pole control system fault level, used to select the incomplete pole converter station. In this embodiment, each pole control host module has at least two fiber optic interfaces, and signals are packaged and transmitted via the Ethernet protocol.

[0066] 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 an optimal signal source based on a pole control state signal transmitted from the same pole of the opposite incomplete pole converter station, and simultaneously transmit the optimal signal source to the duty host and backup host of the same pole of the local incomplete pole converter station. The first digital interface selection unit and the second digital interface selection unit are cross-connected to the duty host and backup host of the same pole of the local incomplete pole converter station.

[0067] Further, if Figure 2 As 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.

[0068] Each digital interface selection module should have at least two ports connected to the incomplete pole converter station on this side and at least one port connected to the incomplete pole converter station on the opposite side. 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 on one side of the incomplete pole converter station via a 100M optical fiber or network cable in a cross-connected manner. Each digital interface selection module has a built-in logic selection program for selecting a better signal source from the received signal source sent by the A host or B host of the opposite incomplete pole converter station based on the pole control status signals, such as the host operating status, DC pole operating status, and pole control system fault level, sent by the pole control host module of the opposite incomplete pole converter station, and simultaneously transmitting it to the A host and B host of the incomplete pole converter station on this side.

[0069] Specifically, the first optical fiber and the second optical fiber each include a plurality of optical fiber communication links, and there should be no fewer than four optical fiber communication links between the two incomplete pole converter stations. Each optical fiber communication link utilizes an independent optical fiber core. The routing of these optical fiber core communication links between the two incomplete pole converter stations does not require specific restrictions. They can be integrated into different optical cables laid between the first incomplete pole converter station and the second incomplete pole converter station. Alternatively, depending on the construction of the communication channel, they can be connected to the fiber distribution frame interface device or other communication device of the existing optical communication network, thereby achieving optical fiber connection via a circuitous 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 status monitoring data from each optical communication maintenance interface module on both sides of each optical fiber communication link. The status monitoring data includes operating mode, self-test data, and optical signal reception data.

[0070] Further, if Figure 2As shown, the first optical fiber and the second optical fiber each include four optical fiber communication links. The first optical fiber includes a first optical fiber communication link 11, a second optical fiber communication link 12, a third optical fiber communication link 13, and a fourth optical fiber communication link 14, and the second optical fiber includes a fifth optical fiber communication link 21, a sixth optical fiber communication link 22, a seventh optical fiber communication link 23, and an eighth optical fiber communication link 24. The first optical communication maintenance interface module includes a first optical communication maintenance interface unit OMI1A and a second optical communication maintenance interface unit OMI1B, the second optical communication maintenance interface module includes a first optical communication maintenance interface unit OMI2A and a second optical communication maintenance interface unit OMI2B, the third optical communication maintenance interface module includes a first optical communication maintenance interface unit OMI3A and a second optical communication maintenance interface unit OMI3B, and the fourth optical communication maintenance interface module includes a first optical communication maintenance interface unit OMI4A and a second optical communication maintenance interface unit OMI4B.

[0071] Each optical communication maintenance interface module should have at least one port connected to the incomplete pole converter station on this side and at least 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 on the side inside the incomplete pole converter station via an optical fiber or network cable with a bandwidth of 100M or above. On the side outside the incomplete pole converter station, it is extended to different optical fiber communication links via a 100M dedicated optical fiber core. It is then connected to the corresponding optical communication maintenance interface module of the incomplete pole converter station on the opposite side via the optical fiber communication link. Each optical communication maintenance interface module is connected to two or more different optical fiber communication links. Each optical fiber communication link is a 100M optical fiber.

[0072] The optical communication maintenance interface module has a preset channel selection strategy integrated inside, and is only connected to one of two or more communication links at the same time. The optical communication maintenance interface module has optical channel detection and switching functions, and the switching function is divided into automatic switching and manual switching. The validity of the optical fiber channel is detected by sending set pulse optical signals in real time. When communication is invalid, it means that the link communication has failed. The optical communication maintenance interface module sends the channel failure signal to the digital interface selection module and automatically switches the communication link. When repairing the communication link, you can switch by manually setting an optical communication maintenance interface module to "maintenance status". At this time, the optical communication maintenance interface module will detect the gap between the two communication packets sent using the Ethernet protocol and switch.

[0073] The aforementioned automatic and manual switching functions are implemented through a preset channel selection strategy for the optical communication maintenance interface module. Specifically, the optimal communication link is selected based on the operating / maintenance status, normal self-test status, and normal pulse light signal reception 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 an operating state, have normal self-test status, and have normal pulse light signal reception, and the optical communication channel is the preferred channel, then that optical communication channel is selected as the optimal fiber optic communication link.

[0074] An embodiment of the present invention provides an inter-station communication device for a series multi-terminal direct current incomplete pole converter station. The 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 a direct connection is established between the stations through optical fiber, which greatly reduces signal transmission delay and realizes high-speed synchronous transmission of various control signals and status information between different converter stations, effectively ensuring the stable operation of the series multi-terminal ultra-high voltage direct current system; optical fiber bandwidth resources are flexibly allocated according to actual communication needs. 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 instructions and trigger angle instructions, which 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 a preset channel selection strategy by analyzing the working mode, self-test data, and optical signal reception data of the modules on both sides of the link. When a link fails, it can quickly switch to a backup link based on status monitoring data to maintain communication stability.

[0075] An embodiment of the present invention provides a method for inter-station communication in a series multi-terminal DC incomplete pole converter station, which is applied to the inter-station communication device in a series multi-terminal DC incomplete pole converter station as described above.

[0076] like Figure 3 As shown, the inter-station communication method includes the steps of:

[0077] S1. 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;

[0078] The duty host and standby host of the first-pole control host module respectively perform closed-loop regulation and control according to the set control targets based on the DC current of the station, the DC port voltage of the station, the operation of each series multi-terminal DC system, etc., and generate the first-pole control system operation data required for various DC operations, namely the first control instructions and the first operation status.

[0079] These control commands and operating status information include four main components: first, commands for regulating the first-pole converters of each converter station, such as control mode and pole current commands; second, commands for regulating the first-pole converter of the converter station itself, such as firing angle and firing pulse commands; third, voltage balance control compensation signals and converter control mode commands for additional inter-pole control of multiple incomplete-pole converter stations; and fourth, status signals such as converter operating status, host duty status (on duty, off duty, and maintenance), and communication health status. The on-duty host and the standby host of the first-pole control host module each package the first control command and first operating status information generated by their respective hosts using the Ethernet protocol. These hosts then send the communication packets to the first and second digital interface selection units of the first digital interface selection module.

[0080] S2. Encrypting the first pole control system operating data to obtain first encrypted data through the first digital interface selection module, and transmitting the first encrypted data to the first optical communication maintenance interface module;

[0081] The first digital interface selection unit and the second digital interface selection unit of the first digital interface selection module respectively receive communication packets from the two hosts of the first control host module, add the self-test normal information of the first data interface selection module, and encrypt the communication packets. The first digital interface selection unit sends the processed communication packets 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 packets to the second optical communication maintenance interface unit of the first optical communication maintenance interface module.

[0082] S3, sending the first encrypted data to the third optical communication maintenance interface module through the first optical fiber via the first optical communication maintenance interface module;

[0083] The first optical communication maintenance interface unit of the first optical communication maintenance interface module sends a communication packet to the first optical communication maintenance interface unit of the third optical communication maintenance interface module via the first optical fiber communication link and the second optical fiber communication link respectively. The second optical communication maintenance interface unit of the first optical communication maintenance interface module sends a communication packet to the second optical communication maintenance interface unit of the third optical communication maintenance interface module via the third optical fiber communication link and the fourth optical fiber communication link respectively.

[0084] The first optical communication maintenance interface module always continuously sends and receives pulsed optical signals to the third optical communication maintenance interface module through the first optical fiber communication link and the second optical fiber communication link according to the settings. The normal / abnormal received pulse signals are used to determine the connection status of the optical fiber path and send the normal operation signal of this module. When the optical communication maintenance interface module at either end fails to detect the pulsed optical signal of a certain optical fiber path continuously, 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 pole converter station. The selection judgment logic includes: 1) When the optical communication maintenance interface module on either side of a channel is in the "maintenance" state, the channel is not selected; 2) When the optical communication maintenance interface module on either side of a channel self-tests abnormally, the channel is not selected; 3) When the receiving end of a channel fails to receive the correct optical communication interface pulse signal, the channel is not selected; 4) When multiple channels are available, the preset preferred channel is used first.

[0085] The first optical communication maintenance interface module can be configured or not configured with an optical power amplifier at the transmitting end according to the length of the transmission optical fiber.

[0086] S4. Transmitting the first encrypted data to the third digital interface selection module through the third optical communication maintenance interface module;

[0087] 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.

[0088] S5. Decrypt the first encrypted data to obtain first decrypted data through the third digital interface selection module, and send the first decrypted data to the third control host module;

[0089] 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 on-duty host in the first-pole control host module from the information obtained from the first-pole control host module, and forwards it to the on-duty host and the standby host of the third-pole control host module at the same time.

[0090] S6. Control the host module through the third stage to read and execute the first decrypted data.

[0091] The duty host and backup host in the third-pole control host module receive information from the duty host in the first-pole control host module. They read the control mode, pole current command, and voltage balance control compensation signal contained in the information, participate in controlling the first-pole converter of the second incomplete pole converter station, and generate the firing angle and firing pulse commands required for regulating the first-pole converter of the second incomplete pole converter station, thereby maintaining the smooth and coordinated operation of the incomplete pole converter stations in the series multi-terminal UHVDC system.

[0092] 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.

[0093] Furthermore, the inter-station communication method further includes the steps of:

[0094] 1) 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;

[0095] The second pole control system operation data includes a second control instruction and a second operation state.

[0096] 2) encrypting the second pole control system operation data to obtain second encrypted data through the second digital interface selection module, and transmitting the second encrypted data to the second optical communication maintenance interface module;

[0097] 3) sending the second encrypted data to the fourth optical communication maintenance interface module through the second optical fiber via the second optical communication maintenance interface module;

[0098] 4) transmitting the second encrypted data to the fourth digital interface selection module via the fourth optical communication maintenance interface module;

[0099] 5) decrypting the second encrypted data to obtain second decrypted data through the fourth digital interface selection module, and sending the second decrypted data to the fourth control host module;

[0100] 6) The fourth-stage control host module reads and executes the second decrypted data.

[0101] 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 specific definitions, refer to the definitions of 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 above. The two have the same functions and effects and will not be repeated here.

[0102] Furthermore, the inter-station communication method further includes the steps of:

[0103] 1) Generate third-pole control system operation data through the third-pole control host module, and send the third-pole control system operation data to the third digital interface selection module;

[0104] The third pole control system operation data includes a third control instruction and a third operation state.

[0105] 2) encrypting the third pole control system operation data through the third digital interface selection module to obtain third encrypted data, and transmitting the third encrypted data to the third optical communication maintenance interface module;

[0106] 3) sending 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;

[0107] 4) transmitting the third encrypted data to the first digital interface selection module through the first optical communication maintenance interface module;

[0108] 5) decrypting the third encrypted data to obtain third decrypted data through the first digital interface selection module, and sending the third decrypted data to the first control host module;

[0109] 6) Reading and executing the third decrypted data through the first-stage control host module.

[0110] 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 definitions, please refer to the definitions of 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 above. The two have the same functions and effects and will not be repeated here.

[0111] Furthermore, the inter-station communication method further includes the steps of:

[0112] 1) Generate fourth pole control system operation data through the fourth pole control host module, and send the fourth pole control system operation data to the fourth digital interface selection module;

[0113] The fourth control system operation data includes a fourth control instruction and a fourth operation state.

[0114] 2) encrypting the fourth pole control system operation data through the fourth digital interface selection module to obtain fourth encrypted data, and transmitting the fourth encrypted data to the fourth optical communication maintenance interface module;

[0115] 3) sending 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;

[0116] 4) transmitting the fourth encrypted data to the second digital interface selection module through the second optical communication maintenance interface module;

[0117] 5) decrypting the fourth encrypted data to obtain fourth decrypted data through the second digital interface selection module, and sending the fourth decrypted data to the second control host module;

[0118] 6) Reading and executing the fourth decrypted data through the second-stage control host module.

[0119] It can be understood that steps 1) to 6) reflect the inter-station communication process in which the fourth-pole control host module sends information to the second-pole control host module. For specific definitions, refer to the definitions of 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 above. The two have the same functions and effects and will not be repeated here.

[0120] In summary, the embodiment of the present invention provides a communication device and method for inter-stations of a series multi-terminal DC incomplete pole converter station. The pole control host modules, digital interface selection modules, and optical communication maintenance interface modules are interconnected in an orderly manner within the incomplete pole converter station, and a direct connection is established between the stations through optical fibers, which greatly reduces the signal transmission delay and realizes high-speed synchronous transmission of various control signals and status information between different converter stations, effectively ensuring the stable operation of the series multi-terminal ultra-high voltage DC system; the optical fiber bandwidth resources are flexibly allocated according to actual communication needs. 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 instructions and trigger angle instructions, which 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 a preset channel selection strategy by analyzing the working mode, self-test data, and optical signal reception data of the modules on both sides of the link. When a link fails, it can quickly switch to the backup link based on the status monitoring data to maintain communication stability.

[0121] Each embodiment in this specification is described in a progressive manner. The same or similar parts of each embodiment can be directly referenced to each other. Each embodiment focuses on the differences from other embodiments. It should be noted that the technical features of the above embodiments can be combined in any way. To keep the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A communication device for serial multi-terminal DC incomplete pole converter stations, applied to a serial multi-terminal UHVDC system, wherein the serial multi-terminal UHVDC system comprises a first incomplete pole converter station and a second incomplete pole converter station, wherein the two incomplete pole converter stations are located at the same sending end or the same receiving end, and each of the incomplete pole converter stations comprises a first pole and a second pole, and wherein: 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 are configured at the first pole in 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 are configured at the second pole in 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 are configured at the first pole in 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 are configured at the second pole in the second incomplete pole converter station and are connected in sequence; The first optical communication maintenance interface module is connected to the third optical communication maintenance interface module via a first optical fiber, and the second optical communication maintenance interface module is connected to the fourth optical communication maintenance interface module via 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, and each of the pole control host modules 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, wherein 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 of the digital interface selection modules is configured to select an optimal signal source based on the pole control status signal sent from the same pole of the incomplete pole converter station on the opposite side, and simultaneously transmit the optimal signal source to the on-duty host and the standby host of the same pole of the incomplete pole converter station on this side.

4. The inter-station communication device according to claim 3, wherein: 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 incomplete pole converter station on this side in a cross-connection manner.

5. The inter-station communication device according to claim 1, wherein: The first optical fiber and the second optical fiber each 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.

6. The inter-station communication device according to claim 5, wherein: Each of the optical communication maintenance interface modules is configured to be connected to the optimal optical fiber communication link of the corresponding optical fiber based on a preset channel selection strategy, wherein the preset channel selection strategy includes selecting the optimal optical fiber communication link based on the status monitoring data of each of the optical communication maintenance interface modules on both sides of each optical fiber communication link, and the status monitoring data includes the working mode, self-test 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 a 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: 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, wherein the first pole control system operation data includes a first control instruction and a first operation state; 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; Sending the first encrypted data to the third optical communication maintenance interface module through the first optical fiber via the first optical communication maintenance interface module; transmitting the first encrypted data to a third digital interface selection module via the third optical communication maintenance interface module; decrypting the first encrypted data to obtain first decrypted data through the third digital interface selection module, and sending the first decrypted data to the third control host module; The first decrypted data is read and executed by the third-party control host module.

8. The inter-station communication method according to claim 7, wherein: 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, wherein the second pole control system operation data includes a second control instruction and a second operation state; Encrypting the second pole control system operation data through the second digital interface selection module to obtain second encrypted data, and transmitting the second encrypted data to the second optical communication maintenance interface module; sending the second encrypted data to the fourth optical communication maintenance interface module through the second optical fiber via the second optical communication maintenance interface module; transmitting the second encrypted data to a fourth digital interface selection module via the fourth optical communication maintenance interface module; decrypting the second encrypted data to obtain second decrypted data through the fourth digital interface selection module, and sending the second decrypted data to the fourth control host module; The fourth pole controls the host module to read and execute the second decrypted data.

9. The inter-station communication method according to claim 7, wherein: The inter-station communication method further includes: Generate third pole control system operation data through the third pole control host module, and send the third pole control system operation data to the third digital interface selection module, wherein the third pole control system operation data includes a third control instruction and a third operation state; Encrypting the third pole control system operation data through the third digital interface selection module to obtain third encrypted data, and transmitting the third encrypted data to the third optical communication maintenance interface module; Sending 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; Transmitting the third encrypted data to the first digital interface selection module through the first optical communication maintenance interface module; decrypting the third encrypted data to obtain third decrypted data through the first digital interface selection module, and sending the third decrypted data to the first pole control host module; The host module is controlled by the first stage to read and execute the third decrypted data.

10. The inter-station communication method according to claim 7, wherein: The inter-station communication method further includes: Generate fourth pole control system operation data through the fourth pole control host module, and send the fourth pole control system operation data to the fourth digital interface selection module, wherein the fourth pole control system operation data includes a fourth control instruction and a fourth operation state; Encrypting the fourth pole control system operation data through the fourth digital interface selection module to obtain fourth encrypted data, and transmitting the fourth encrypted data to the fourth optical communication maintenance interface module; sending 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; transmitting the fourth encrypted data to the second digital interface selection module through the second optical communication maintenance interface module; decrypting the fourth encrypted data through the second digital interface selection module to obtain fourth decrypted data, and sending the fourth decrypted data to the second pole control host module; The host module is controlled by the second stage to read and execute the fourth decrypted data.

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