SCADA redundant system based on PRP networking

Abstract

The invention relates to an SCADA redundant system based on PRP networking, which comprises a process layer, a spacing layer, a switch, a station control layer, a process layer PRP network, a spacing layer PRP network and a station control layer PRP network, the process layer is in communication connection with the process layer PRP network, the spacing layer is in communication connection with the spacing layer PRP network, the station control layer is in communication connection with the station control layer PRP network, the station control layer PRP network is in communication connection with the spacing layer PRP network through a switch, the process layer PRP network is in communication connection with the spacing layer PRP network, and each of the process layer, the spacing layer and the station control layer comprises two interfaces. Each of the process layer PRP network, the spacing layer PRP network and the station control layer PRA network comprises two sub-networks, the two interfaces are respectively in communication connection with the two corresponding sub-networks, redundant data packets are verified and discarded through a discarding algorithm, and results are output or warning information is generated. The PRP technology and the discarding algorithm are used, and the reliability of the system is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent substations, and in particular to a SCADA redundancy system based on PRP networking. Background Art

[0002] SCADA (Supervisory Control And Data Acquisition) system, namely data acquisition and supervisory control system. SCADA power monitoring system is an industrial automation control system that integrates data acquisition, data monitoring, integrated control, human-machine interface, real-time events, event processing, historical events, system logs, protection operations, fixed value management, recording analysis, network topology diagram, graphic configuration, parameter configuration and other modules. It can collect field data in real time, conduct local or remote control of industrial sites, and use algorithms to provide further auxiliary analysis and production scheduling decisions.

[0003] Parallel Redundancy Protocol (PRP) is a network redundancy protocol that ensures reliable data transmission by sending the same data packet simultaneously on two independent network channels. At the sending end of the SCADA system, the PRP protocol will copy each data packet to be sent and send it simultaneously through two independent network channels. These two independent network channels (usually physically completely isolated networks) will transmit the same data packet in parallel. At the receiving end, the system will receive data packets from both channels at the same time and check the received redundant data packets. The receiving end will select one of the valid data packets for subsequent processing and discard the duplicate data packets. If one network channel fails, the receiving end can still receive the complete data packet from the other channel, thereby achieving seamless switching and ensuring uninterrupted communication.

[0004] In order to ensure the continuous and effective operation of the SCADA power monitoring system, its functional reliability and stability need to be given special consideration. Communication technology is the key to the realization of substation automation system. It connects various intelligent electronic devices in the station and is an indispensable functional carrier for real-time information exchange within the substation. Combined with the IEC 62439 standard research, the new network technology based on the PRP parallel redundancy principle is adopted. Different network solutions are used for different functional data flows to divide and optimize the network, so as to promote the reasonable establishment of the SCADA system network and achieve the real-time and reliability of network communication.

[0005] The invention patent with publication number CN107864051A discloses a method for solving computer equipment failure in an electric power monitoring system and an electric power monitoring system. Through virtual machine technology, hardware redundancy of computer equipment is realized. After deployment, when any physical machine hardware fails, the virtual machine will perform fault migration, which will not affect the operation of application software; a redundant network based on PRP or HSR technology is constructed, and the principle of PRP or HSR technology is used to ensure that any line failure or damage in the network will not affect the normal operation of the system; through PRP / HSR conversion equipment, related devices are connected to the constructed redundant network, so that devices that originally do not support redundant networks are connected to the redundant network; the patent realizes network redundancy through PRP / HSR technology. The use of HSR technology requires the addition of additional switches and redundant boxes, and too many switches will limit the flexibility of network division. Using only PRP technology is more reliable than PRP / HSR technology; the existing discard algorithm only chooses to discard redundant data according to the order of receiving data, and does not compare after delayed data reception to ensure data consistency.

[0006] Therefore, it is an urgent problem to provide a SCADA redundant system that uses PRP technology throughout the entire process and whose discard algorithm can compare data. Summary of the invention

[0007] The purpose of the present invention is to provide a SCADA redundancy system based on PRP networking in order to overcome the defects of the above-mentioned prior art.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] According to one aspect of the present invention, a SCADA redundant system based on PRP networking is provided, comprising a process layer, an interval layer, a switch and a station control layer, the switch having an embedded discarding algorithm, the system also comprising a process layer PRP network, an interval layer PRP network and a station control layer PRP network, the process layer and the process layer PRP network are communicatively connected, the interval layer and the interval layer PRP network are communicatively connected, the station control layer and the station control layer PRP network are communicatively connected, the station control layer PRP network is communicatively connected with the interval layer PRP network through a switch, the process layer PRP network and the interval layer PRP network are communicatively connected, the process layer, the interval layer and the station control layer each comprise two interfaces, the process layer PRP network, the interval layer PRP network and the station control layer PRP network each comprise two sub-networks, the two interfaces are communicatively connected with the corresponding two sub-networks respectively, the switch verifies and discards redundant data packets through a discarding algorithm, and outputs the result or generates a warning message.

[0010] As a preferred technical solution, the process layer includes a merging unit and an intelligent terminal, and the merging unit and the intelligent terminal each include two interfaces. The two interfaces of the merging unit are respectively communicated with the two sub-networks of the process layer PRP network, and the two interfaces of the intelligent terminal are respectively communicated with the two sub-networks of the process layer PRP network.

[0011] As a preferred technical solution, the interval layer includes a protection device and a control device, and the protection device and the control device each include two interfaces. The two interfaces of the protection device are respectively communicatively connected to the two sub-networks of the interval layer PRP network, and the two interfaces of the control device are respectively communicatively connected to the two sub-networks of the interval layer PRP network.

[0012] As a preferred technical solution, the switch includes a first switch and a second switch, the first switch is respectively communicatively connected to the process layer PRP network and the interval layer PRP network, and the second switch is respectively communicatively connected to the process layer PRP network and the interval layer PRP network.

[0013] As a preferred technical solution, the first switch is communicatively connected to the control device, and the second switch is communicatively connected to the protection device.

[0014] As a preferred technical solution, the spacer layer PRP network and the station control layer PRP network are communicatively connected via a first switch and a second switch.

[0015] As a preferred technical solution, the station control layer includes a monitoring host, a gateway and other hosts, the gateway is respectively communicated with the monitoring host and other hosts, the monitoring host, the gateway and other hosts each include two ports, the two ports of the monitoring host are respectively communicated with the station control layer PRP network, the two ports of the gateway are respectively communicated with the station control layer PRP network, and the two ports of the other hosts are respectively communicated with the station control layer PRP network.

[0016] As a preferred technical solution, the interfaces of the process layer, the bay layer and the station control layer are independently configured with IP addresses.

[0017] As a preferred technical solution, the system further includes a remote control center, which is communicatively connected to the station control layer PRP network.

[0018] As a preferred technical solution, the process of discarding algorithm verification and discarding includes the following steps:

[0019] S1. If two data packets are received in sequence within the first preset time, the data packet received later is discarded and the data packet received earlier is output;

[0020] S2. If only one data packet is received within the first preset time, the data packet is output;

[0021] S3, if only one data packet is received within the first preset time and the second data packet is received within the second preset time, the two data packets are compared;

[0022] S4. If the comparison results are consistent, the second data packet is discarded; if the comparison results are inconsistent, a warning message is prompted;

[0023] S5. If only one data packet is received within the first preset time and the second data packet is not received within the second preset time, a warning message is generated;

[0024] S6. If the data packet is not received within the first preset time, a warning message is generated.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The system of the present invention uses PRP technology throughout the process. Two switches are required to build dual networks. The PRP networking method is used from the station control layer. There is no need to add additional switches and redundant boxes. When a single network fails, the system will automatically switch to another network to continue communication, ensuring the reliability of the system, greatly reducing the uncertainty factors caused by system failures and saving maintenance costs.

[0027] 2. The discarding algorithm of the present invention selects to compare data packets within different preset times. If the comparison results of the data packets are inconsistent or the corresponding data packets are not received for a long time, a warning message is generated to prompt the staff of the system failure and to handle it, so as to ensure the safety of the system operation.

[0028] 3. In the present invention, two networks run PRP at the same time, and the switches in the network are in a normal forwarding state. There is no connection between the parallel redundant dual networks. Therefore, even if a single network fails, the message notifying the network topology change will not cause an impact on the other network. As long as the other network runs normally at the same time, the message will not be lost. The networking method realizes the dual-network sending of important GOOSE messages, reduces the impact of the background traffic that maintains the network topology information on the transmission function, reduces the burden on the switch, and increases the reliability of message transmission.

[0029] 4. The present invention adopts the PRP network to realize information sharing, and at the same time, can significantly improve the redundancy of the station control layer network without increasing the network cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall network connection method of the present invention;

[0031] Figure 2 It is a schematic diagram of the operation of the process layer PRP network of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Parallel Redundancy Protocol (PRP) is a network redundancy protocol that ensures reliable data transmission by sending the same data packet simultaneously on two independent network channels. At the sending end of the SCADA system, the PRP protocol will copy each data packet to be sent and send it simultaneously through two independent network channels. These two independent network channels (usually physically completely isolated networks) will transmit the same data packet in parallel. At the receiving end, the system will receive data packets from both channels at the same time and check the received redundant data packets. The receiving end will select one of the valid data packets for subsequent processing and discard the duplicate data packets. If one network channel fails, the receiving end can still receive the complete data packet from the other channel, thereby achieving seamless switching and ensuring uninterrupted communication.

[0034] In order to ensure the continuous and effective operation of the SCADA power monitoring system, its functional reliability and stability need to be given special consideration. Communication technology is the key to the realization of substation automation system. It connects various intelligent electronic devices in the station and is an indispensable functional carrier for real-time information exchange within the substation. Combined with the IEC 62439 standard research, the new network technology based on the PRP parallel redundancy principle is adopted. Different network solutions are used for different functional data flows to divide and optimize the network, so as to promote the reasonable establishment of the SCADA system network and achieve the real-time and reliability of network communication.

[0035] The concept of the present invention is as follows: two networks run PRP at the same time, and the switches in the network are in a normal forwarding state. There is no connection between the parallel redundant dual networks, so even if a single network fails, the message notifying the network topology change will not cause an impact on the other network. As long as the other network runs normally at the same time, the message will not be lost. This networking method realizes the dual-network transmission of important GOOSE messages, reduces the impact of background traffic that maintains network topology information on the transmission function, reduces the burden on the switch, and increases the reliability of message transmission.

[0036] The redundancy function of the PRP network refers to the implementation of dual standby at the node device. The PRP network is based on two parallel network architectures that do not affect each other in physical structure. Network devices can transmit data in two networks at the same time and provide seamless switching in the event of a link failure. The PRP network includes two connection methods: double-attached node DANP (Double Attached Node implementing PRP) and single-attached node SAN (Singly Attached Node). DANP is directly connected to two independent and parallel LANs to achieve dual-network communication. SAN can directly access the LAN, but the communication range is limited to the connected LAN. It can also access two LANs through a redundancy box (RedBox) to achieve dual-network communication.

[0037] The above-mentioned PRP networking method performs redundancy in nodes rather than networks, that is, redundancy is performed using dual-connected nodes DANP that comply with PRP. DANP is connected to two independent LANs with similar topologies, named LAN_A and LAN_B, which run in parallel. The DANP source node copies a data frame into two copies, adds a PRP identifier, and sends it to the two LANs. After a period of time, the target node receives the data frame from the two LANs respectively. However, there may be a time difference in the data frames received by the target node. This is because there are differences in network delays. The data may arrive at the receiving end at different times. Therefore, the receiving end may receive data from one network first, and then receive the same data from another network. However, PRP has a discard algorithm, which selects the first data frame to arrive, discards the data frames that arrive later, and removes the PRP identifier of the received data frame.

[0038] If one of the two parallel networks fails, the system may switch to the other network to continue communication. However, when the failed network is restored, the device will continue to send data to the network. This mechanism may cause data retransmission, and the target node may receive the same data that has been received through the other network. At this time, the PRP protocol will also use the discard algorithm to discard duplicate data frames.

[0039] In the PRP duplicate message discarding mode, the sender adds a 4-byte redundant control tracking bit after each data frame to handle duplicate messages. Each DANP contains two network cards with the same physical address and network address, connected to the network layer through a redundant link body. The redundant link body is responsible for redundant management and message processing. When the network layer sends a frame, the redundant link body at the sender copies the frame into two frames and adds a redundant control tag RCT. The two frames are sent from LAN_A and LAN_B respectively. The two frames pass through the two LANs with different delays. Ideally, they arrive at the destination almost at the same time. When receiving, the redundant link body at the receiving end receives the frame that arrives first and forwards it to the upper layer, and discards the duplicate frame that arrives later.

[0040] Therefore, the present invention provides a SCADA redundant system based on PRP networking; the system of the present invention uses PRP technology throughout the whole process, and two switches are required when building a dual network. The PRP networking mode is used from the station control layer, and no additional switches and redundant boxes are required. When a single network fails, the system will automatically switch to another network to continue communication, ensuring the reliability of the system, greatly reducing the uncertainty factors caused by system failures and saving maintenance costs. The discarding algorithm of the present invention selects to compare data packets within different preset times, and generates warning information when the data packet comparison results are inconsistent or the corresponding data packets are not received for a long time, prompting the staff of the system failure and processing, thereby ensuring the safety of system operation. The two networks of the present invention run PRP at the same time, and the switches in the network are in a normal forwarding state. There is no connection between the parallel redundant dual networks, so even if a single network fails, the message notifying the network topology change will not cause an impact on the other network. As long as the other network runs normally at the same time, the message will not be lost. The networking mode realizes the dual-network transmission of important GOOSE messages, and also reduces the influence of the background traffic maintaining the network topology information on the transmission function, reduces the burden of the switch, and increases the reliability of message transmission. The present invention adopts the PRP network to realize information sharing, and at the same time can significantly improve the redundancy of the station control layer network without increasing the network cost.

[0041] Example 1

[0042] like Figure 1 , Figure 2As shown, a SCADA redundant system based on PRP networking includes a process layer, an interval layer, a switch and a station control layer, the switch has an embedded discarding algorithm, the system also includes a process layer PRP network, an interval layer PRP network and a station control layer PRP network, the process layer and the process layer PRP network are communicated, the interval layer and the interval layer PRP network are communicated, the station control layer and the station control layer PRP network are communicated, the station control layer PRP network is communicated with the interval layer PRP network through a switch, the process layer PRP network and the interval layer PRP network are communicated, the process layer, the interval layer and the station control layer each include two interfaces, the process layer PRP network, the interval layer PRP network and the station control layer PRP network each include two sub-networks, the two interfaces are respectively communicated with the corresponding two sub-networks, the switch verifies and discards redundant data packets through a discarding algorithm, and outputs the result or generates a warning message.

[0043] In this embodiment, the process layer, interval layer and station control layer devices of the SCADA power monitoring system are all connected to the network switch through the network port. After the process layer devices collect SV data and GOOSE switch signals, they are sent to the network switch in the form of Ethernet data. The interval layer devices obtain SV and other information from the shared network on demand for processing to achieve protection, measurement and control and other functions. The station control layer devices obtain MMS information through the shared network to achieve effective monitoring of the entire station information. The redundant network based on PRP is configured according to the following redundant structure. Each layer of the power monitoring system includes two ports, each of which is configured with an independent IP address. Each port is independently connected to a different network switch, and LAN_A and LAN_B are used as a distinction. The device publishes the same message to the dual network respectively, and the dual network also subscribes to these messages to achieve redundancy of the device communication network.

[0044] Station control layer PRP network, the data characteristics of the station control layer are mostly sudden and random data, the data volume is small, there is a certain demand for information sharing, and the real-time requirements are low. The use of PRP network can realize information sharing, and at the same time, it can significantly improve the redundancy of the station control layer network without increasing the network cost. And it can fully meet the communication performance requirements of the station control layer. The interval layer PRP network, through GOOSE information communication, the protection devices of the system interval layer need to interact with each other internally, and use the PRP network for cascading to realize the GOOSE network function. The process layer PRP network, the PRP network can meet special communication performance requirements. The SV message sent by the combiner can still ensure the communication quality in the case of a single network failure.

[0045] The process layer includes a merging unit and an intelligent terminal, each of which includes two interfaces. The two interfaces of the merging unit are respectively connected to the two sub-networks of the process layer PRP network for communication, and the two interfaces of the intelligent terminal are respectively connected to the two sub-networks of the process layer PRP network for communication.

[0046] The spacing layer includes a protection device and a control device, each of which includes two interfaces. The two interfaces of the protection device are respectively connected to the two sub-networks of the spacing layer PRP network for communication, and the two interfaces of the control device are respectively connected to the two sub-networks of the spacing layer PRP network for communication.

[0047] The switch includes a first switch and a second switch, wherein the first switch is communicatively connected to the process layer PRP network and the bay layer PRP network respectively, and the second switch is communicatively connected to the process layer PRP network and the bay layer PRP network respectively.

[0048] The first switch is communicatively connected to the control device, and the second switch is communicatively connected to the protection device.

[0049] The bay layer PRP network and the station control layer PRP network are communicatively connected via a first switch and a second switch.

[0050] In this embodiment, there are multiple control devices, protection devices, merging units and intelligent terminals, which transmit relevant information to their respective networks.

[0051] The station control layer includes a monitoring host, a gateway and other hosts. The gateway is respectively connected to the monitoring host and other hosts in communication. The monitoring host, the gateway and other hosts each include two ports. The two ports of the monitoring host are respectively connected to the station control layer PRP network communication. The two ports of the gateway are respectively connected to the station control layer PRP network communication. The two ports of the other hosts are respectively connected to the station control layer PRP network communication.

[0052] The interfaces of the process layer, the bay layer and the station control layer are independently configured with IP addresses.

[0053] The system also includes a remote control center, which is connected to the station control layer PRP network communication.

[0054] In this embodiment, each port is independently connected to a different network switch by configuring independent IP addresses respectively, and long-distance transmission to the outside can be achieved through the gateway.

[0055] The process of discarding algorithm verification and discarding includes the following steps:

[0056] S1. If two data packets are received in sequence within the first preset time, the data packet received later is discarded and the data packet received earlier is output;

[0057] S2. If only one data packet is received within the first preset time, the data packet is output;

[0058] S3, if only one data packet is received within the first preset time and the second data packet is received within the second preset time, the two data packets are compared;

[0059] S4. If the comparison results are consistent, the second data packet is discarded; if the comparison results are inconsistent, a warning message is prompted;

[0060] S5. If only one data packet is received within the first preset time and the second data packet is not received within the second preset time, a warning message is generated;

[0061] S6. If the data packet is not received within the first preset time, a warning message is generated.

[0062] In this embodiment, if the corresponding data packet is not received within the specified time, it may be caused by a system failure. At the same time, the information of the delayed received data packet is inconsistent with the information of the previously received data packet, which may be caused by a failure. A warning message is generated to facilitate troubleshooting.

[0063] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A SCADA redundant system based on PRP networking, comprising a process layer, a bay layer, a switch and a station control layer, wherein the switch has an embedded discard algorithm, characterized in that: The system also includes a process layer PRP network, an interval layer PRP network and a station control layer PRP network. The process layer and the process layer PRP network are communicatively connected, the interval layer and the interval layer PRP network are communicatively connected, and the station control layer and the station control layer PRP network are communicatively connected. The station control layer PRP network is communicatively connected to the interval layer PRP network via a switch. The process layer PRP network and the interval layer PRP network are communicatively connected. The process layer, the interval layer and the station control layer each include two interfaces. The process layer PRP network, the interval layer PRP network and the station control layer PRP network each include two sub-networks. The two interfaces are communicatively connected to the corresponding two sub-networks respectively. The switch verifies and discards redundant data packets through a discard algorithm, and outputs the results or generates a warning message.

2. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The process layer includes a merging unit and an intelligent terminal, each of which includes two interfaces. The two interfaces of the merging unit are respectively connected to the two sub-networks of the process layer PRP network for communication, and the two interfaces of the intelligent terminal are respectively connected to the two sub-networks of the process layer PRP network for communication.

3. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The spacing layer includes a protection device and a control device, each of which includes two interfaces. The two interfaces of the protection device are respectively connected to the two sub-networks of the spacing layer PRP network for communication, and the two interfaces of the control device are respectively connected to the two sub-networks of the spacing layer PRP network for communication.

4. A SCADA redundant system based on PRP networking according to claim 3, characterized in that: The switch includes a first switch and a second switch, wherein the first switch is communicatively connected to the process layer PRP network and the bay layer PRP network respectively, and the second switch is communicatively connected to the process layer PRP network and the bay layer PRP network respectively.

5. A SCADA redundant system based on PRP networking according to claim 4, characterized in that: The first switch is communicatively connected to the control device, and the second switch is communicatively connected to the protection device.

6. A SCADA redundant system based on PRP networking according to claim 4, characterized in that: The spacer layer PRP network and the station control layer PRP network are communicatively connected via a first switch and a second switch.

7. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The station control layer includes a monitoring host, a gateway and other hosts. The gateway is respectively connected to the monitoring host and other hosts in communication. The monitoring host, the gateway and other hosts each include two ports. The two ports of the monitoring host are respectively connected to the station control layer PRP network communication. The two ports of the gateway are respectively connected to the station control layer PRP network communication. The two ports of the other hosts are respectively connected to the station control layer PRP network communication.

8. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The interfaces of the process layer, the bay layer and the station control layer are independently configured with IP addresses.

9. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The system also includes a remote control center, which is connected to the station control layer PRP network communication.

10. A SCADA redundant system based on PRP networking according to claim 1, characterized in that: The process of discarding algorithm verification and discarding includes the following steps: S1. If two data packets are received in sequence within the first preset time, the data packet received later is discarded and the data packet received earlier is output; S2. If only one data packet is received within the first preset time, the data packet is output; S3, if only one data packet is received within the first preset time and the second data packet is received within the second preset time, the two data packets are compared; S4. If the comparison results are consistent, the second data packet is discarded; if the comparison results are inconsistent, a warning message is prompted; S5. If only one data packet is received within the first preset time and the second data packet is not received within the second preset time, a warning message is generated; S6. If the data packet is not received within the first preset time, a warning message is generated.

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