750kv substation secondary system networking system and networking method

Abstract

This invention belongs to the field of substation automation technology, and relates to a networking system and method for a 750kV substation secondary system. The system includes station control layer equipment, bay layer equipment, and process layer equipment. Bay layer equipment and process layer equipment communicate directly point-to-point via dedicated optical fiber, without the need for a process layer switch. Station control layer equipment and bay layer equipment are connected via a station control layer network. The station control layer network includes physically independent or logically isolated A, B, and C networks. Network A connects a dual-configuration A-set of protection and a dual-configuration A-set of safety automatic devices. Network B connects a dual-configuration B-set of protection and a dual-configuration B-set of safety automatic devices. Network C connects station control layer monitoring equipment, single-configuration protection devices, single-configuration measurement and control devices, and single-configuration safety automatic devices. This invention achieves deterministic communication delay and limits the impact of faults to a single bay.

Description

Technical Field

[0001] This invention belongs to the field of substation automation technology, and relates to a 750kV substation secondary system networking system and networking method. Background Technology

[0002] With the advancement of the construction of new power systems based on new energy sources, substation secondary systems face higher requirements for reliability, real-time performance, and security. As an important component of the backbone power grid, the stable operation of the secondary systems at the 750kV voltage level is crucial to the safety of the entire power grid.

[0003] In traditional smart substations, secondary systems typically construct a shared Ethernet network based on process layer switches between bay-level and process-level devices. This leads to a series of inherent drawbacks: the architecture introduces single-point-of-failure risks due to its reliance on process switches, the failure of which may cause the protection and control functions of multiple bays connected to the network to fail; the store-and-forward mechanism of the switches results in uncertain communication latency, making it difficult to meet the deterministic requirements of protection services; the shared network suffers from the inherent vulnerability to network storms, with abnormal traffic easily spreading and crowding out critical bandwidth, threatening real-time message transmission; furthermore, the complex network configuration increases the burden of engineering implementation and maintenance, and raises equipment costs. Summary of the Invention

[0004] The purpose of this invention is to provide a networking system and method for a 750kV substation secondary system, in order to solve the technical problems of high single-point failure risk, uncertain communication delay, easy network storm, and heavy maintenance burden caused by the use of process layer switches to build a shared Ethernet network in the existing 750kV substation secondary system.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a 750kV substation secondary system networking system, comprising: Station control layer equipment, including station control layer monitoring equipment; The spacer layer equipment includes a protection device and a monitoring and control device. The protection device includes a dual-configuration A-set protection, a dual-configuration A-set automatic safety device, a dual-configuration B-set protection, a dual-configuration B-set automatic safety device, a single-set protection device, and a single-set automatic safety device. The monitoring and control device includes a single-set monitoring and control device. Process-level equipment, including data acquisition and execution units; The spacer layer device and the process layer device communicate directly point-to-point via a dedicated optical fiber, and no process layer switch is provided. The station control layer equipment and the interval layer equipment are connected through a station control layer network; The station control layer network includes physically independent or logically isolated A network, B network, and C network; The A network is used to connect the dual-configuration A-set protection and the dual-configuration A-set automatic safety device; The B network is used to connect the dual-configuration B-set protection and the dual-configuration B-set automatic safety device; The C-network is used to connect station control layer monitoring equipment, individually configured protection devices, individually configured measurement and control devices, and individually configured automatic safety devices.

[0006] Furthermore, the dedicated optical fiber is used to transmit SV messages and GOOSE messages simultaneously.

[0007] Furthermore, the dedicated optical fiber is a single pair of optical fibers and uses multimode fiber. The SV message and the GOOSE message are transmitted through the same pair of optical fibers via a common port and do not pass through any switching equipment.

[0008] Furthermore, the A network and B network are networked using physically independent switches, or the A network, B network and C network are divided by logically isolated switches.

[0009] Furthermore, the station control layer network is configured with a broadcast storm suppression function, and a preset threshold limit is set for the input rate of broadcast messages and multicast messages.

[0010] Furthermore, the station control layer network is configured to give GOOSE messages a higher priority than ordinary data messages.

[0011] Furthermore, the station control layer network adopts a star topology and is configured with a fast spanning tree protocol.

[0012] Furthermore, the process layer device also includes an acquisition and execution unit, which integrates analog signal acquisition function and digital signal input / output function.

[0013] Based on the above system, this invention also discloses a networking method for a 750kV substation secondary system, comprising the following steps: S1: The acquisition and execution unit sends SV messages to the protection device in a point-to-point manner through a dedicated optical fiber; S2: The protection device determines whether a fault has occurred based on the received SV message. If a fault is determined to have occurred, a GOOSE trip command is sent to the acquisition and execution unit through the same dedicated optical fiber. S3: Cross-bay interlocking signals are transmitted between bay-level devices through the corresponding subnets of the station control layer network. Among them, the dual-configuration A-set protection and dual-configuration A-set safety automatic devices communicate through the A network, the dual-configuration B-set protection and dual-configuration B-set safety automatic devices communicate through the B network, and other data are transmitted through the C network.

[0014] Furthermore, in S3, when the station control layer network switch detects that the input rate of broadcast or multicast messages on a certain port exceeds a preset threshold, it automatically suppresses the abnormal traffic forwarding of that port.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The system of this invention includes: station control layer equipment, bay layer equipment, and process layer equipment. The station control layer equipment includes station control layer monitoring equipment; the bay layer equipment includes protection devices and measurement and control devices. The protection devices include a dual-configuration A-set protection, a dual-configuration A-set automatic safety device, a dual-configuration B-set protection, a dual-configuration B-set automatic safety device, a single-configuration protection device, and a single-configuration automatic safety device. The measurement and control devices include a single-configuration measurement and control device; the process layer equipment includes a data acquisition and execution unit. The bay layer equipment and the process layer equipment communicate directly point-to-point via dedicated optical fiber, without the need for a process layer switch, to eliminate process layer communication issues. This system mitigates the single-point-of-failure risk of equipment replacement, achieves deterministic communication latency, and provides immunity to network storms. The station control layer equipment and the interval layer equipment are connected via a station control layer network. This network comprises physically independent or logically isolated A, B, and C networks. Network A connects a dual-configuration A-set protection system and a dual-configuration A-set automatic safety device. Network B connects a dual-configuration B-set protection system and a dual-configuration B-set automatic safety device. Network C connects station control layer monitoring equipment, single-configuration protection devices, single-configuration measurement and control devices, and single-configuration automatic safety devices. This ensures mandatory isolation between protection services and monitoring / management services, guaranteeing that any network anomaly or traffic congestion will not affect other functional networks. This system eliminates the single-point failure risk of process layer switches, achieves deterministic communication latency, and is immune to network storms by eliminating process layer switches and adopting point-to-point direct communication. At the same time, by dividing the station control layer network into A network, B network, and C network, it achieves mandatory isolation between protection services and monitoring and management services, ensuring that any network anomaly or traffic congestion will not affect other functional networks.

[0016] Method S1: The data acquisition and execution unit sends SV messages to the protection device in a point-to-point manner via a dedicated optical fiber. This invention uses a dedicated optical fiber for point-to-point transmission of SV messages, avoiding the store-and-forward delay of the switch and ensuring real-time and reliable transmission of sampled data. S2: The protection device determines whether a fault has occurred based on the received SV messages. If a fault is detected, it sends a GOOSE trip command to the data acquisition and execution unit via the same dedicated optical fiber. In this invention, SV and GOOSE are transmitted on the same optical fiber port without passing through a switching device, achieving deterministic delay in the trip command and ensuring fast and reliable tripping in case of a fault. S3: Cross-bay interlocking signals are transmitted between bay-level devices through the corresponding subnets of the station control layer network. Specifically, the dual-configuration A-set protection and dual-configuration A-set safety automatic devices communicate via the A-network, the dual-configuration B-set protection and dual-configuration B-set safety automatic devices communicate via the B-network, and other data are transmitted via the C-network. This invention features independent dual protection networks (A and B) and a monitoring network (C), achieving mandatory isolation between protection and monitoring / management services. An anomaly in one network does not affect other networks. By using point-to-point fiber optic direct connection, this invention eliminates the single-point-of-failure risk of process-layer switches, achieves deterministic latency communication, and is immune to network storms. Through the isolation of networks A, B, and C, it ensures the independence of dual protection and prevents interference between protection and monitoring services, thus constructing a highly reliable, real-time, and secure communication method. Attached Figure Description

[0017] Figure 1 This is a system module diagram of the present invention; Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] The relevant terms in this invention are explained as follows: Point-to-point networking: This refers to a communication connection method in which the interval layer equipment (such as protection devices and measurement and control devices) and the process layer equipment (acquisition and execution units) are directly connected through a dedicated optical fiber link, and the data packets are not forwarded through any intermediate switching equipment.

[0021] Process layer switch: refers to a network switching device deployed at the process layer in a conventional smart substation, used to aggregate and forward SV and GOOSE messages from multiple bays.

[0022] Station control layer network: refers to a redundant exchange network that connects station control layer equipment (such as monitoring host and gateway) and bay layer equipment, and is used to transmit monitoring, management and cross-bay interlocking data.

[0023] Bay layer: refers to the logical hierarchy of related equipment (such as protection devices and measurement and control devices) in the secondary system of a substation, which are configured according to electrical bays to realize functions such as protection, control and measurement.

[0024] Process layer: refers to the logical layer of related equipment (such as acquisition and execution units) in the secondary system of a substation that directly interface with the primary equipment to realize functions such as electrical quantity acquisition, status monitoring and command execution.

[0025] Acquisition and execution unit: refers to an intelligent electronic device deployed at the process layer that integrates functions such as analog signal acquisition and digital signal input / output, and communicates with the interval layer devices through a digital interface.

[0026] Redundant dual network: refers to the use of two physically independent, parallel network architectures in the station control layer network to improve the reliability of the communication channel.

[0027] GOOSE: an abbreviation for Generic Object Oriented SubstationEvent, which refers to fast and reliable multicast or point-to-point communication messages used to transmit substation events (such as switch changes and protection trip commands).

[0028] SV: Abbreviation for Sampled Value, refers to the data message that is collected by process layer equipment through current transformers, such as analog quantities of primary equipment current and voltage, and then digitized according to a standard format and sent to bay layer protection, measurement and control equipment.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1: See Figure 1 This invention discloses a 750kV substation secondary system networking system, including: station control layer equipment, bay layer equipment and process layer equipment.

[0030] Station control layer equipment includes station control layer monitoring equipment; The spacer layer equipment includes a protection device and a monitoring and control device. The protection device includes a dual-configuration A-set protection, a dual-configuration A-set automatic safety device, a dual-configuration B-set protection, a dual-configuration B-set automatic safety device, a single-set protection device, and a single-set automatic safety device. The monitoring and control device includes a single-set monitoring and control device. Process layer devices include data acquisition and execution units.

[0031] The interval layer device and the process layer device communicate directly point-to-point via dedicated optical fiber, without the need for a process layer switch. This eliminates the risk of single point of failure of the process layer switch, achieves deterministic communication latency, and is immune to network storms.

[0032] In a preferred embodiment of the present invention, the dedicated optical fiber is used to transmit SV messages and GOOSE messages simultaneously.

[0033] In a preferred embodiment of the present invention, the dedicated optical fiber is a single pair of optical fibers and uses multimode optical fiber. The SV message and the GOOSE message are transmitted through the same pair of optical fibers via a common port and do not pass through any switching equipment.

[0034] The station control layer equipment and the interval layer equipment are connected through the station control layer network.

[0035] The station control layer network includes physically independent or logically isolated A network, B network, and C network.

[0036] The A network is used to connect the dual-configuration A-set protection and the dual-configuration A-set automatic safety device; The B network is used to connect the dual-configuration B-set protection and the dual-configuration B-set automatic safety device; The C-network is used to connect station control layer monitoring equipment, individually configured protection devices, individually configured measurement and control devices, and individually configured automatic safety devices. This achieves mandatory isolation between protection services and monitoring and management services, ensuring that any network anomaly or traffic congestion will not affect other functional networks.

[0037] In a preferred embodiment of the present invention, network A and network B are networked using physically independent switches, or network A, network B and network C are divided by logically isolated switches.

[0038] In a preferred embodiment of the present invention, the station control layer network is configured with a broadcast storm suppression function, and a preset threshold limit is set for the input rate of broadcast messages and multicast messages.

[0039] In a preferred embodiment of the present invention, the station control layer network is configured with a higher priority for GOOSE messages than for ordinary data messages.

[0040] In a preferred embodiment of the present invention, the station control layer network adopts a star topology and is configured with a fast spanning tree protocol.

[0041] In a preferred embodiment of the present invention, the process layer device further includes an acquisition and execution unit, which integrates analog quantity acquisition function and digital quantity input and output function.

[0042] This system eliminates the single-point failure risk of process layer switches, achieves deterministic communication latency, and is immune to network storms by eliminating process layer switches and adopting point-to-point direct communication. At the same time, by dividing the station control layer network into A network, B network, and C network, it achieves mandatory isolation between protection services and monitoring and management services, ensuring that any network anomaly or traffic congestion will not affect other functional networks.

[0043] See Figure 2 Based on the above-mentioned 750kV substation secondary system networking system, this invention also discloses a 750kV substation secondary system networking method, including the following steps: S1: The data acquisition and execution unit sends SV messages to the protection device in a point-to-point manner via a dedicated optical fiber. Using dedicated optical fiber for point-to-point transmission of SV messages avoids the store-and-forward latency of traditional process layer switches, ensuring the real-time and deterministic nature of sampled value transmission. Simultaneously, it eliminates the risk of sampled data loss due to switch failure, guaranteeing the integrity and reliability of the sampled data acquired by the protection device.

[0044] S2: The protection device determines whether a fault has occurred based on the received SV message. If a fault is detected, it sends a GOOSE trip command to the acquisition and execution unit via the same dedicated optical fiber. The SV and GOOSE messages are transmitted through the same optical fiber pair via a common port without passing through a switching device, achieving microsecond-level deterministic latency for the protection trip command. The point-to-point direct connection ensures a fixed transmission path for fault diagnosis and trip command, avoiding the impact of network congestion or storms on the trip command. This ensures that the protection device can quickly and reliably drive the circuit breaker to operate and isolate the fault in the event of a fault.

[0045] S3: Cross-bay interlocking signals are transmitted between bay-level devices through the corresponding subnets of the station control layer network. Specifically, the dual-configuration A-set protection and dual-configuration A-set safety automatic devices communicate via the A-network, the dual-configuration B-set protection and dual-configuration B-set safety automatic devices communicate via the B-network, and other data is transmitted via the C-network. This invention places the dual-configuration protection system in physically independent or logically isolated A-networks and B-networks, ensuring that anomalies, congestion, or maintenance in either network will not affect the communication of the other protection system, thus guaranteeing the effectiveness of the dual-configuration at the communication level. Simultaneously, it forcibly isolates protection services (A / B networks) from monitoring and management services (C network), preventing non-real-time traffic from impacting critical protection messages, achieving fault domain minimization and ensuring that services do not interfere with each other.

[0046] In a preferred embodiment of the present invention, in step S3, when the station control layer network switch detects that the input rate of broadcast or multicast messages on a certain port exceeds a preset threshold, it automatically suppresses the abnormal traffic forwarding of that port.

[0047] This method achieves SV message reception and GOOSE trip command transmission through point-to-point fiber optic direct connection, eliminating the risk of single-point failure of process layer switches, realizing deterministic time-delay communication of protection services end-to-end, and is immune to the impact of network storms on critical messages. At the same time, through the isolation of the A / B / C three-network partitions at the station control layer, it ensures that the communication of the dual protection system is independent of each other, and that protection services and monitoring and management services do not interfere with each other. Thus, a highly reliable, high real-time, and high-security communication method for substation secondary systems is systematically constructed.

[0048] Example 2: The purpose of this invention is to propose a lower-level communication architecture for a computer monitoring system in 750kV substations that offers higher determinism and a smaller fault impact range. It aims to fundamentally avoid the systemic risks that may arise from using process-layer switching networks by simplifying the network structure.

[0049] See Figure 1The system networking scheme of this invention maintains the basic structure of three layers: station control layer, bay layer, and process layer. All bay layer protection and measurement / control equipment and process layer acquisition and execution units are physically connected point-to-point using dedicated optical fibers. SV and GOOSE messages are transmitted through the same pair of optical fiber ports without passing through any switching equipment. No independent process layer switches are configured throughout the station, and no shared process layer Ethernet is established. The entire station forms two clear physical network layers: one is a direct connection network between the bay layer and the process layer composed of point-to-point optical fibers; the other is a redundant switching network between the station control layer and the bay layer composed of station control layer switches, used to carry non-real-time or cross-bay data such as monitoring and management. To achieve network isolation and functional partitioning, the station control layer network is functionally divided into: Network A, consisting of a dual-configuration A set of protection and a dual-configuration A set of automatic safety devices; Network B, consisting of a dual-configuration B set of protection and a dual-configuration B set of automatic safety devices; and Network C, consisting of station control layer monitoring equipment, a single-configuration protection device, a single-configuration measurement / control device, and a single-configuration automatic safety device.

[0050] In this embodiment, the core feature of the 750kV substation secondary system networking scheme is: point-to-point direct connection eliminates the process layer network, and station control layer partition isolation realizes functional decoupling.

[0051] In terms of logical architecture, the 750kV substation secondary system still maintains a three-layer division of station control layer, bay layer, and process layer. However, in terms of physical connection and network organization, this solution eliminates the independent, switch-based process layer network, replacing it with direct point-to-point fiber optic connections between bay layer and process layer devices. Simultaneously, the station control layer network, which carries out in-station monitoring, management, and cross-bay interlocking services, has undergone refined network isolation and functional partitioning.

[0052] The bay-level protection, measurement and control equipment, and the process-level acquisition and execution units communicate via a point-to-point fiber optic network using SV and GOOSE messages, eliminating the need for a separate process-level network based on process-level switches. By completely eliminating process-level switches, the potential single point of failure caused by such equipment is eliminated at its source. In traditional architectures, a failure of a single process-level switch can cause the protection sampling and tripping functions of multiple connected bays to fail simultaneously, resulting in a wide impact. Point-to-point direct connection ensures that the communication links of each bay are completely independent, and a failure of any link is strictly confined to that bay, minimizing the scope of the fault's impact. Regarding real-time performance, because the message transmission path is fixed and there is no store-and-forward, queuing, or scheduling process involving intermediate switching nodes, the communication latency becomes constant and accurately predictable, fully meeting the stringent requirements of relay protection and other services for microsecond-level deterministic latency. More importantly, this design is physically immune to network storms, an inherent defect of shared Ethernet. On dedicated, point-to-point directly connected links, there are no broadcast or multicast domains. Abnormal traffic generated on one port cannot propagate to other links, thus eliminating the risk of critical GOOSE packets being lost or delayed due to the proliferation of broadcast or multicast packets. Furthermore, the simplified network structure brings convenience to operation and maintenance. Clear physical connections make fault location intuitive and eliminate the workload of configuring complex switch parameters, reducing operational complexity and the probability of errors.

[0053] After eliminating the process layer network, the station control layer network becomes the only switch-based communication network within the station, carrying a rich array of services including monitoring, management, and cross-bay interlocking. To ensure its reliability and isolate the mutual influence between different services, the solution proposes a refined management strategy of station control layer partitioning and isolation to achieve functional decoupling. This strategy first requires the station control layer network to adopt a redundant dual-network configuration with a star topology, that is, to deploy two independent physical networks in parallel to meet high availability requirements. Based on this, its core innovation lies in strictly dividing the station control layer network in Security Zone I into three functional subnets: A network, B network, and C network through logically isolated switches. The specific partitioning principle is as follows: the A-set protection and the A-set safety automatic devices with dual configurations are used to access the A network; the B-set protection and the B-set safety automatic devices with dual configurations are used to access the B network; station control layer monitoring equipment (such as integrated main and auxiliary monitoring hosts and real-time gateways), single-configuration protection devices, single-configuration measurement and control devices, and single-configuration safety automatic devices are used to access the C network. The fundamental purpose of this partitioning design is to achieve strict service isolation and fault domain isolation. By placing the two protection systems on physically independent A and B networks respectively, it is ensured that any anomaly, congestion, attack, or planned maintenance in one network will not affect the communication of the other protection system, thus guaranteeing the effectiveness of the dual configuration at the communication level. Simultaneously, isolating the high-real-time protection services (A / B networks) from the station control layer monitoring and management services (C network) with relatively lower real-time requirements but potentially larger data volumes effectively prevents the potential impact of non-real-time traffic such as monitoring data streams and file transfers on the transmission of critical messages such as protection GOOSE messages and substation secondary system communication messages (CMS), constructing a highly deterministic communication environment for core functions. The scheme also stipulates that the station control layer network should not be connected to process layer equipment, and the switches transmitting dual protection messages should be configured independently, further strengthening the isolation effect.

[0054] To ensure the stable and reliable operation of the above architecture, the next-generation networking solution is equipped with a comprehensive, multi-dimensional technical support system. First, the solution emphasizes proactive management based on traffic models. According to this networking technical solution, theoretical calculations and evaluations of normal traffic and burst traffic (such as simultaneous actions at multiple intervals) should be performed during the design phase. Based on this, port-level and protocol-level traffic control strategies must be implemented on the switches. For example, setting thresholds for the input rate of broadcast or multicast packets and assigning the highest priority to GOOSE packets are necessary for traffic shaping and scheduling to prevent the loss of critical packets due to burst traffic congestion. Second, regarding network risks, switches must have broadcast storm suppression capabilities and preferably multicast traffic control capabilities. When the port input traffic exceeds a preset threshold, the switch should be able to automatically suppress the forwarding of abnormal traffic to prevent it from spreading into a network-wide storm. Furthermore, through network redundancy and rapid self-healing mechanisms such as dual-network redundancy, device-level redundancy, and Rapid Spanning Tree Protocol (RSTP), it is ensured that communication can quickly switch to backup paths and maintain service continuity when network links or devices fail.

[0055] The advantages of this invention stem from its fundamental architectural innovation. The new generation of substation secondary system networking scheme, by adopting direct point-to-point fiber optic connections between bay-level and process-level equipment and eliminating the independent process-level switching network, inevitably generates multiple core advantages: This design physically eliminates the process-level switch as a single point of failure, thus significantly improving system reliability; because the communication link is dedicated and there are no intermediate switching links, it completely avoids the latency uncertainty introduced by switch store-and-forward and the inherent network storm propagation risk of shared network architecture, ensuring deterministic real-time transmission of protection and other services; at the same time, the simplified network structure inevitably reduces system configuration complexity and maintenance burden. Furthermore, the station control layer network is functionally divided into three subnets: A, B, and C, forcibly isolating the dual protection system (A / B network) from station control layer monitoring and other services (C network). This division ensures the physical independence of critical protection services and minimizes the fault domain, ensuring that any network anomaly or traffic congestion will not affect other functional networks, thereby constructing a highly reliable and highly deterministic communication foundation as a whole.

[0056] In summary, the new generation substation secondary system networking scheme of this embodiment takes point-to-point direct connection and zone isolation as its two pillars. Through the thorough simplification of the architecture and the clear decoupling of functions, it systematically builds a highly reliable, real-time, and secure secondary system communication foundation.

[0057] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A 750 kV substation secondary system networking system, characterized in that, include: Station control layer equipment, including station control layer monitoring equipment; The spacer layer equipment includes a protection device and a monitoring and control device. The protection device includes a dual-configuration A-set protection, a dual-configuration A-set automatic safety device, a dual-configuration B-set protection, a dual-configuration B-set automatic safety device, a single-set protection device, and a single-set automatic safety device. The monitoring and control device includes a single-set monitoring and control device. Process-level equipment, including data acquisition and execution units; The spacer layer device and the process layer device communicate directly point-to-point via a dedicated optical fiber, and no process layer switch is provided. The station control layer equipment and the interval layer equipment are connected through a station control layer network; The station control layer network includes physically independent or logically isolated A network, B network, and C network; The A network is used to connect the dual-configuration A-set protection and the dual-configuration A-set automatic safety device; The B network is used to connect the dual-configuration B-set protection and the dual-configuration B-set automatic safety device; The C-network is used to connect station control layer monitoring equipment, individually configured protection devices, individually configured measurement and control devices, and individually configured automatic safety devices.

2. The 750 kV substation secondary system networking system of claim 1, wherein, The dedicated optical fiber is used to transmit SV messages and GOOSE messages simultaneously.

3. The 750 kV substation secondary system networking system of claim 2, wherein, The dedicated optical fiber is a single pair of optical fibers and uses multimode fiber. The SV message and GOOSE message are transmitted through the same pair of optical fibers via a common port and do not pass through any switching equipment.

4. The 750kV substation secondary system networking system according to claim 1, characterized in that, The A network and B network are networked using physically independent switches, or the A network, B network and C network are divided by logically isolated switches.

5. The 750kV substation secondary system networking system according to claim 1, characterized in that, The station control layer network is equipped with a broadcast storm suppression function, and a preset threshold limit is set for the input rate of broadcast messages and multicast messages.

6. The 750kV substation secondary system networking system according to claim 5, characterized in that, The station control layer network is configured to give GOOSE messages a higher priority than ordinary data messages.

7. The 750kV substation secondary system networking system according to claim 1, characterized in that, The station control layer network adopts a star topology and is configured with a fast spanning tree protocol.

8. The 750kV substation secondary system networking system according to claim 1, characterized in that, The process layer device also includes an acquisition and execution unit, which integrates analog quantity acquisition function and digital quantity input and output function.

9. A method for networking a secondary system of a 750kV substation, employing the 750kV substation secondary system networking system as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: The acquisition and execution unit sends SV messages to the protection device in a point-to-point manner through a dedicated optical fiber; S2: The protection device determines whether a fault has occurred based on the received SV message. If a fault is determined to have occurred, a GOOSE trip command is sent to the acquisition and execution unit through the same dedicated optical fiber. S3: Cross-bay interlocking signals are transmitted between bay-level devices through the corresponding subnets of the station control layer network. Among them, the dual-configuration A-set protection and dual-configuration A-set safety automatic devices communicate through the A network, the dual-configuration B-set protection and dual-configuration B-set safety automatic devices communicate through the B network, and other data are transmitted through the C network.

10. A method for networking a secondary system of a 750kV substation according to claim 9, characterized in that, In S3, when the station control layer network switch detects that the input rate of broadcast or multicast messages on a certain port exceeds a preset threshold, it automatically suppresses the abnormal traffic forwarding of that port.

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