WO2018049584A1 - Method for avoiding data message collision in communication network within substation - Google Patents

Abstract

The present invention relates to a method for avoiding a data message collision in a communication network within a substation, characterized by comprising the following: 1) distinguishing a message data source for data service sources of GOOSE, SV, MMS and IEEE1588; 2) identifying a data message type according to the result of distinguishing the massage data source; 3) enabling a data message priority mechanism to define a substation service according to the priorities of different data message types; 4) defining a data message multicast management protocol of the substation; 5) defining a corresponding data message CSMA policy for different data message types; and 6) defining a corresponding data message collision avoidance algorithm for different data message types. The invention can avoid the communication network in the substation becoming congested, reduce the packet loss rate and delay of the communication service, improve the performance of the communication network within the substation, and improve the real-time performance, stability and reliability of the operation of the substation.

Description

Method for avoiding data message collision in communication network in substation Technical field

The invention relates to a method for avoiding collision of data messages in a communication network in a substation, and relates to the technical field of power systems.

Background technique

In order to meet the needs of intelligent substations, the future substation equipment will gradually move toward functional integration and structural integration. The integration of primary and secondary equipment will be closer and the boundaries will be more blurred. Realizing comprehensive analysis and automatic collaborative control is the key to intelligent substation. Digitalization of equipment information, functional integration, compact structure and maintenance automation are the future development directions of substations. The IEC61850 standard is a complete communication standard for substation automation systems. It is the most important supporting technology for intelligent substation construction, and has a profound impact on the design of substation automation systems and protection control products. The IEC61850 standard proposes the concept of communication stratification in substation. The substation communication system is divided into substation layer, interval layer and process layer. Process layer devices are interconnected through process layer bus, and interval layer devices are interconnected through station control layer bus. The direction of data flow in the substation has the same horizontal data exchange and vertical data exchange between layers. Data exchange at different levels and in different directions requires different data flow and time response characteristics. The communication information network in the substation is a dedicated data communication network for carrying functions such as protection, measurement and control, measurement, PMU (Phase Measurement Unit), fault recording, etc., depending on the specific application, the network data of the station The information includes GOOSE (Generic object oriented substation event), SV (Sample Value), MMS (Manufacturing Message Specification) and time information. The communication network in the IEC61850 substation is mainly composed of network communication devices and cables. The network communication devices in the substation include industrial Ethernet switches, bridges or low-latency real-time network communication devices.

The seven-layer reference model of the OSI (Model for Open Systems Interconnection) includes the physical layer, the data link layer, the network layer, and the transport layer. , Session, Presentation, and Application. The data link layer (Data Link) includes a medium access control sublayer (Media Access Control, MAC) and a logical link control sublayer (Logical Link Control, LLC) in order from bottom to top. The communication network in the IEC61850 substation mainly involves the lower three layers of the OSI seven-layer reference model, namely the physical layer, the data link layer and the network layer. “Three-layer equipment” in “three-layer two-network” refers to process layer equipment (merging unit, intelligent terminal integration), bay level equipment (protection, measurement and control, The metering device is integrated in whole or in part) and the station control layer device. “Two networks” refers to the process layer network and the station control layer network. In the process layer network, the uplink information is mainly current/voltage sample value data (SV message), transformer/switch state quantity data (GOOSE message), and the downlink information is generally operation control command (GOOSE message); station control layer network The uplink information is mainly the status, action, and alarm information (MMS message) generated by the secondary function device, and the downlink information is mainly the operation control command (GOOSE message). The "three-layer equipment" in the "three-layer-one network" is the same as above, and the "one-network" refers to the "integrated network" in which information is exchanged between layers and layers. The device devices in the "two-layer-one-network" are divided into the ground layer and the substation layer according to the realization functions, and the information exchange between the layers and the devices in the layer is realized by the "one-layer network".

IEEE 1588 (ie, IEC 61588) network time-of-day data is also referred to as time-of-day message data. The IEEE 802.1q protocol, the "Virtual Bridged Local Area Networks" (virtual bridged local area network) protocol, mainly specifies the implementation method of the VLAN. Tag is the identifier of the VLAN defined by the IEEE802.1q protocol in the data frame; the ACCESS port, the TRUNK port is the name of the manufacturer for a certain port. The definition of a VLAN member can be divided into four types: (1) VLANs are classified according to ports: The method for dividing VLANs is based on the ports of the Ethernet switch. For example, ports 1 to 4 of a switch are VLAN A, 5 to 17 is VLAN B, and 18 to 24 are VLAN C. The above ports belonging to the same VLAN group can be discontinuous. How to configure them depends on the administrator. In addition, if there are multiple switches, for example, you can specify that ports 1 to 6 of switch 1 and ports 1 to 4 of switch 2 are the same VLAN, that is, the same VLAN can span several Ethernet switches. According to port division, it is the most commonly used method for defining VLANs. The IEEE 802.1q protocol specifies how to divide VLANs according to the ports of the switch. The advantage of this method of partitioning is that it is very simple to define VLAN members, just define all the ports. Its disadvantage is that if the user of VLAN A leaves the original port and reaches a port of a new switch, it must be redefined. (2) Dividing VLANs according to MAC addresses: This method of dividing VLANs is divided according to the MAC address of each host, that is, the host to which each MAC address belongs is assigned which group it belongs to. The biggest advantage of this method of dividing VLANs is that when the user's physical location moves, that is, when switching from one switch to another, the VLAN does not need to be reconfigured. Therefore, it can be considered that the division method according to the MAC address is based on the user's VLAN. The disadvantage of this method is that all users must be configured during initialization. If there are hundreds or even thousands of users, the configuration task is very heavy. Moreover, this method of partitioning also leads to a reduction in the efficiency of the switch execution, because there may be many members of a VLAN group on each switch's port, so that the broadcast packet cannot be restricted. In addition, for users who use laptops, their network cards may be replaced frequently, so VLANs must be constantly configured. (3) Divide VLANs according to the network layer: This method of dividing VLANs is divided according to the network layer address or protocol type of each host (if multi-protocol is supported). Although this method of partitioning may be based on a network address, such as an IP address, a subnet mask, but it is not a route, not with the network layer. The route is confusing. Although it looks at the IP address of each packet, it is not a route, so there is no routing protocol such as RIP (Routing Information Protocol), OSPF (Open Shortest Path First), but a spanning tree. The algorithm performs bridge switching. The advantage of this method is that the user's physical location changes, there is no need to reconfigure the VLAN to which he belongs, and the VLAN can be divided according to the protocol type, which is very important for the network administrator. Also, this method does not need to be attached. The frame label identifies the VLAN, which reduces network traffic. The disadvantage is that it is inefficient, because checking the network layer address of each packet is very time consuming (relative to the previous two methods), the general switch chip can automatically check the Ethernet frame header of the packet on the network, but let The chip can check the IP header, which requires higher technology and is more time consuming. (4) According to IP multicast division: IP multicast is actually a VLAN definition, that is, a multicast group is considered to be a VLAN group. This method of partitioning extends VLANs to the WAN, so this approach has more flexibility and is easily extended by routers. Of course, this method is not suitable for the local area network, and the efficiency is not high. For the multicast of the local area network, there is a layer 2 multicast protocol GMRP. Since the GOOSE message and the SV message on the process layer network of the substation are only transmitted at the data link layer and there is no encapsulation structure of the third layer (IP layer), the above third and fourth VLAN division methods are not applicable to the substation process layer. The internet.

The IEEE 802.1p protocol (LAN Layer 2 QoS/CoS Protocol for Traffic Prioritization) is related to the traffic priority LAN Layer 2 QoS/CoS protocol. The IEEE 802.1p protocol enables Layer 2 switches to provide traffic prioritization and dynamic multicast filtering services. The priority specification works in the Media Access Control (MAC) frame layer (the second layer of the OSI Reference Model). The standard also provides multicast traffic filtering to ensure that the traffic does not exceed the scope of the Layer 2 switching network. The 802.1p protocol header includes a 3-bit priority field that supports grouping packets into various traffic classes. IEEE strongly recommends that network administrators implement these types of traffic, but do not require mandatory use. 802.1p traffic is simply categorized and sent to the destination without a bandwidth reservation mechanism. There is a collision problem of data packets in the communication network in the existing substation, and the collision will lead to network congestion, thereby increasing the packet loss rate and delay.

Summary of the invention

In view of the above problems, an object of the present invention is to provide a method for avoiding data packet collision in a communication network in a substation, which can avoid congestion of a communication network, reduce packet loss rate and delay, improve performance of a communication network in a substation, and improve a substation. Work stability and reliability.

In order to achieve the above object, the present invention adopts the following technical solution: a method for avoiding data packet collision in a communication network in a substation, including the following contents: 1) performing message data for data service sources of GOOSE, SV, MMS, and IEEE1588 Source distinguishing; 2) discriminating the data packet type according to the result of the packet data source; 3) enabling the data packet priority mechanism to prioritize the substation service according to different data packet types The level is defined; 4) defines the data packet multicast management protocol of the substation; 5) defines the corresponding data packet CSMA policy for different data packet types; 6) defines the corresponding data packet avoidance conflict algorithm for different data message types.

Preferably, according to the attribute type of the device/device and the MAC address of the device/device, the data source in the communication network in the IEC61850 substation is distinguished, that is, the fast GOOSE message data source, the regular GOOSE message data source, and the sampling rate is 256. Point/week SV message data source, SV message data source with sampling rate of 80 points/week, MMS message data source and time-based message data source; if device/device attribute type and device/device MAC address The same is true, and the device/device appears as the source of the packet data of the above two types of packet data sources, and the data of the six types of data packets from the physical port of the device/device Source distinction.

Preferably, the six types of data packets in the communication network of the IEC 61850 substation are distinguished by the data packet type discrimination according to the packet data source distinguishing result, that is, the fast GOOSE message and the regular GOOSE message, and the sampling rate is 256 points/week. The SV packet, the sampling rate is 80 points/week SV message, MMS message, and time-based message.

Preferably, the data packet priority mechanism is divided into eight priority queues, 7 is the highest priority, and is sequentially decreased, and the substation service packet priority is defined: the fast GOOSE packet priority queue number is 7, and the regular GOOSE message takes precedence. The SV packet priority queue number is 5, the sampling rate is 256 points/week, and the SV packet priority queue number is 4, and the MMS packet priority queue number is 4. 3. The priority queue number of the time packet is 2.

Preferably, the data packet multicast management protocol includes a manual data packet multicast management protocol and an automatic data packet multicast management protocol, a manual data packet multicast management adopts a VLAN protocol, and automatic data packet multicast management adopts a GMRP ( GARP Multicast Registration Protocol.

Preferably, the VLAN protocol is a VLAN standard protocol defined by IEEE 802.1q, and the static multicast mode includes a multicast MAC address, a VLAN number, and a port mode. The IEC 61850 substation communication network supports a maximum of 4096 VLANs and supports forwarding. The tag header, the delete tag header, or the modified tag header are inserted in the text frame to support the VLAN trunk function.

Preferably, the GMRP protocol is a GMRP standard protocol defined by IEEE 802.1p. The maximum number of dynamic multicasts supported is 256, the Join Time is 200 ms, the Leave Time is 600 ms, and the Leave All Time is 10000 ms.

Preferably, the fast GOOSE message, the regular GOOSE message, the SV message with a sampling rate of 256 points/week, and the SV message with a sampling rate of 80 points/week adopt a continuous CSMA strategy: the continuous CSMA strategy is: when the substation When the internal communication network is busy or conflicts, the device that wants to send the message continuously monitors, and when there is idle, the message can be sent; the MMS message and the time-based message adopt the p-persistent CSMA policy, and the p-continuous CSMA The strategy is: does not continuously monitor the channel, but waits for a random one when the communication network is busy or conflicts in the substation. The segment time Δt, the device that is to send the message sends the message according to the probability of p, and does not send the message according to the probability of q=1-p.

Preferably, the fast message message, the regular GOOSE message, the SV message with a sampling rate of 256 points/week, and the data message avoidance conflict algorithm used for the SV message with a sampling rate of 80 points/week are CSMA/CP algorithms. The data packet avoidance collision algorithm used in the MMS message is the CSMA/CA algorithm; the time-based message uses the CSMA/CD algorithm.

The invention adopts the above technical solutions, and has the following six advantages: 1. The invention effectively solves the data packet collision problem in the communication network in the IEC61850 substation, thereby avoiding the congestion of the communication network, reducing the packet loss rate and delay, and improving The performance of the communication network in the IEC61850 substation improves the real-time performance, stability and reliability of the substation, further enhances the intelligent level of the substation, and can construct the communication network in the IEC61850 substation economically, flexibly and efficiently. 2. The invention distinguishes six types of data messages in the communication network of the IEC61850 substation, namely, a fast GOOSE message, a regular GOOSE message, an SV message with a sampling rate of 256 points/week, and a sampling rate of 80 points/week. SV packets, MMS packets, and time-based packets use data packet priority mechanism, data packet multicast management protocol, data packet CSMA policy, and data packet avoidance conflict algorithm to implement datagrams in the IEC61850 substation communication network. The collision avoidance of the text meets the needs of automation and intelligence of substation operation management. 3. The present invention utilizes a one-to-one correspondence between a specific MAC address and a device or a device, and can further distinguish a device or device that is a data source by using a MAC address, and therefore has a MAC address-based bundling function, and the specific packet data source is correspondingly The MAC address of the device or device of the data source provides the basis for collision avoidance of data messages in the communication network of the IEC61850 substation based on the MAC address-based bundling function. 4. The data packet priority mechanism is enabled in the present invention, and all physical resources are shared for service data packets with different real-time requirements to ensure that application messages with real-time requirements can be delivered 100% within a specified time. The communication network management in the IEC61850 substation provides convenience and facilitates operation and maintenance. 5. The invention realizes the collision avoidance of data packets in the communication network of the IEC61850 substation, and is applicable to the application scenarios of the "three-layer equipment layer 2 network", the "three-layer equipment layer network" and the "two-layer equipment layer network". The trend of technology trends from “intelligent device” to “intelligent device” changes the status of network configuration with complex networking methods and low equipment utilization, simplifies the level of information network in the station, realizes multiple information common network transmission, and improves network technology. The application level meets the requirements of IEC61850 substation integrated monitoring system and smart grid panoramic information acquisition application, and provides information communication for the substation to achieve the overall goal of “high system integration, reasonable structural layout, advanced equipment application, economic energy saving and environmental protection, support and regulation integration”. Technical support and protection. 6. The invention guarantees the common network transmission of the communication services such as GOOSE, SV, MMS and IEEE1588 network ("four networks in one"), realizes data sharing, resource sharing, simplifies the number of network switches and optical fibers, and can not only solve substation engineering The problems encountered in the design process can also face the difficulties in operation and maintenance, improve the utilization rate, reliability and utilization of the device ports, and effectively reduce the network construction and operation costs. The invention can be widely applied to data processing transmission of a communication network in a substation.

DRAWINGS

1 is a flow chart of a method for avoiding data packet collision in a communication network in a substation according to the present invention.

detailed description

The invention is described in detail below with reference to the accompanying drawings. It is to be understood, however, that the appended claims

The IEC61850 substation internal communication network is a dedicated data communication network for carrying functional services such as protection, measurement and control, metering, PMU, fault recording, etc. According to the specific application, the network information in the station includes GOOSE, SV, MMS and time information. class.

As shown in FIG. 1, the method for avoiding data packet collision in the intra-substation communication network of the present invention includes the following contents:

1. For the data service sources of GOOSE, SV, MMS and IEEE1588 (ie IEC61588), the message data source is distinguished.

The devices connected to the communication network in the substation all have a MAC address-based bundling function, and the present invention can distinguish the data sources by the MAC address. According to the attribute type of the device/device and the MAC address of the device/device, the invention distinguishes six types of data sources in the communication network of the IEC61850 substation, namely: fast GOOSE message data source, regular GOOSE message data source, sampling rate SV packet data source of 256 points/week, SV packet data source with sampling rate of 80 points/week, MMS message data source and time-based message data source. If the attribute type of the device/device and the MAC address of the device/device are the same, and the device/device appears as the source of the packet data of two or more of the above six types of packet data sources, from the device / The physical port of the device performs data source differentiation of the above six types of data messages.

2. Identify the data packet type based on the result of the packet data source.

According to the data source source differentiation result, the data packet type identification distinguishes 6 types of data messages in the communication network of the IEC61850 substation, namely: fast GOOSE message, regular GOOSE message, SV report with sampling rate of 256 points/week. SV packets, MMS packets, and time-based packets with a sampling rate of 80 points/week.

3. Enable the data packet priority mechanism to define the priority of the substation service according to different data packet types.

The data packet priority mechanism of the present invention is divided into eight priority queues, 7 being the highest priority, decreasing in turn, and 0 being the lowest priority. Substation service packet priority definition: fast GOOSE packet priority queue number is 7, regular GOOSE packet priority queue number is 6, and sampling rate is 256 points/week SV packet priority queue number is 5, sampling rate The priority queue number of the 80-point/week SV packet is 4, the priority queue number of the MMS packet is 3, and the priority queue number of the timing packet is 2.

4. Define the data packet multicast management protocol for the substation.

The data packet multicast management protocol of the present invention includes a manual data packet multicast management protocol and an automatic data packet multicast management protocol, and a manual data packet multicast management adopts a VLAN protocol, which is suitable for a new substation; an automatic data packet group. The broadcast management adopts the GMRP protocol and is suitable for the upgrading of existing substations.

The VLAN protocol is the VLAN standard protocol defined by IEEE 802.1q. The static multicast mode includes the multicast MAC address, the VLAN number, and the port mode. The IEC61850 substation communication network supports a maximum of 4096 VLANs and supports the forwarding of the packet. Insert the tag header, delete the tag header or modify the tag header to support the VLAN Trunk function. The GMRP protocol is a GMRP standard protocol defined by IEEE 802.1p. The maximum number of dynamic multicasts supported is 256, the Join Time is 200ms, the Leave Time is 600ms, and the Leave All Time is 10000ms.

5. Define the corresponding data packet CSMA policy for different data packet types.

Fast GOOSE message, regular GOOSE message, SV message with a sampling rate of 256 points/week, and SV message with a sampling rate of 80 points/week adopt the continuous CSMA (ie, 1-persistent CSMA) strategy, the continuous CSMA strategy When the communication network in the substation is busy or conflicts, the device that wants to send the message continuously monitors continuously, and when there is idle, the message can be sent;

The MMS message and the time-based message adopt a p-persistent CSMA policy, which is: does not continuously monitor the channel, but waits for a random period of time Δt when the communication network is busy or conflicts in the substation, The device that sends the message sends the message according to the probability of p, does not send the message according to the probability of q=1-p, and Δt randomly takes the set of millisecond time numbers {1, 2, 3, 4, 5, 6, 7, 8, 9 One of the elements of 10}, the unit is ms, and the method of randomly selecting the natural number of 1-10 is "=INT(RAND()*10)+1"; the p value is associated with the number of retransmissions of the transmitted message, When the number of retransmissions is 1 and 2, p=0.5, when the number of retransmissions of the message is 3 and 4, p=0.4, the number of retransmissions of the message is 5 and 6 is p=0.3, and the number of retransmissions of the message When 7 and 8 are p=0.2, the number of retransmissions of the message is 9 and 10, p=0.1, and the number of retransmissions of the message exceeds 10, p=0.

6. Define corresponding data packet avoidance conflict algorithms for different data packet types.

The fast GOOSE message corresponds to the relay protection, monitoring/SCADA and five-defense service data. It is used to transmit the tripping and blocking commands, and has extremely high requirements for real-time and reliability. The conventional GOOSE message corresponds to relay protection, monitoring/SCADA, fault recording, status monitoring, protection information system and five-proof service data, and is used to transmit switch displacement information. SV messages with a sampling rate of 256 points/week are used to transmit power quality and energy metering information. The SV message with a sampling rate of 80 points/week is used for transmission protection, measurement and control, PMU and fault recording information. MMS messages are used to transmit network management and configuration, fault logging, telecontrol, variable lists, variable reading and writing, summoning directories, summoning files, and proactive reporting. The time-series message is used to transmit the precise timing information, and belongs to the IEEE1588 (ie IEC61588) network time-of-day service. The fast message message of the present invention, the conventional GOOSE message, the SV message with a sampling rate of 256 points/week, and the data message avoidance conflict algorithm adopted by the SV message with a sampling rate of 80 points/week CSMA/CP (ie carrier sense multiple access/carrier priority) algorithm;

The data packet avoidance conflict algorithm used in the MMS message is CSMA/CA (ie, carrier sense multiple access/collision avoidance) algorithm; the timed message adopts CSMA/CD (ie carrier sense multiple access/collision detection) algorithm .

Further, the IEC 61850 substation of a "three-layer device layer network" is used as a specific embodiment to describe how to distinguish the GOOSE message data source: this embodiment adopts a MAC address-based VLAN division method to distinguish the GOOSE message data source. Specifically, if the destination MAC address of the received frame is between 0x010CCD010000 and 0x010CCD0101FF, and the Ethernet type value is 0x88B8, it is determined that the received frame is a GOOSE message data source, and is sent to the corresponding port for the GOOSE message. If the destination MAC address of the received frame does not belong between 0x010CCD010000 and 0x010CCD0101FF, it is determined that the received frame is a normal frame and is forwarded according to a forwarding mechanism; if the destination MAC address of the received frame is between 0x010CCD010000 and 0x010CCD0101FF, Ethernet If the type value is not 0x88B8, it is determined that the received frame is a normal frame and is forwarded according to a forwarding mechanism.

Further, the IEC 61850 substation of a "three-layer device layer network" is used as a specific embodiment to describe how to use the port-based VLAN division method to distinguish packet data sources. Specifically, according to the port connected by the IED (Intelligent Electronic Device) device, VLAN partitioning is performed according to different GOOSE control block ports and SV data block ports, that is, different GOOSE and SV packet data sources are set with different VLAN tags. The switch performs VLAN division according to the transmission and reception relationship of GOOSE and SV packets. The data source of the MMS, SV, and GOOSE packets will appear on the same network. In order to effectively isolate the data sources of the MMS, SV, and GOOSE packets, the MMS packet data source needs to be traffic-limited according to the protocol type to ensure MMS. The packet data source occupies the maximum network bandwidth and prevents the MMS packet from affecting the data source of the SV and GOOSE packets. The SV and GOOSE packet data sources specify the maximum traffic of each packet according to the multicast traffic restriction. Realize effective isolation between MMS, SV, GOOSE message data sources. For example, when a port receives a merged unit SV packet and a smart terminal GOOSE packet data source, the SV packet data source traffic of the input switch is too large, and the switch internally inputs the bandwidth according to the data packet priority mechanism. The merging unit packets with excessive traffic are partially discarded. GOOSE will not be affected on the output port to ensure the reliability of other packets.

Further, the IEC61850 substation of a "two-layer device layer network" defines a data packet multicast management protocol for a specific embodiment: MMS, GOOSE, SV, IEEE1588 (ie, IEC61588) report file common network transmission, wherein the manual datagram The multicast management adopts the VLAN protocol, and the static multicast mode includes the multicast MAC address, the VLAN number, and the port mode. There are 4096 VLANs in the communication network in the substation, which supports inserting the tag header and deleting the tag header in the forwarded message frame. Or modify the tag header to support the VLAN Trunk function.

The above embodiments are only used to illustrate the present invention, and various implementation steps and the like of the method may be changed. Any equivalent transformation and improvement based on the technical solution of the present invention should not be excluded from the present invention. Outside the scope of protection.

Claims (9)

A method for avoiding data packet collision in a communication network in a substation, characterized in that the following content is included: 1) Differentiate the data source of the message for the data service sources of GOOSE, SV, MMS and IEEE1588; 2) According to the data source source differentiation result, the data message type identification is performed; 3) Enable the data packet priority mechanism to define the priority of the substation service according to different data packet types; 4) Define a data packet multicast management protocol for the substation; 5) Define a corresponding data packet CSMA policy for different data packet types; 6) Define corresponding data packet avoidance conflict algorithms for different data message types. A method for avoiding collision of data packets in an intra-substation communication network according to claim 1, wherein the IEC 61850 substation communication network is distinguished according to the attribute type of the device/device and the MAC address of the device/device Data source, namely: fast GOOSE message data source, regular GOOSE message data source, SV message data source with sampling rate of 256 points/week, SV message data source with sampling rate of 80 points/week, MMS message Data source and time-of-day message data source; if the device/device attribute type and the device/device MAC address are the same, and the device/device appears as the class 2 or above of the above 6 types of message data sources In the case of a text data source, the data source of the above six types of data messages is distinguished from the physical port of the device/device. A method for avoiding collision of data packets in a communication network in a substation as claimed in claim 2, characterized in that, according to the classification result of the data source of the message, the six types of communication networks in the IEC 61850 substation are distinguished by data packet type identification. The data message is a fast GOOSE message, a regular GOOSE message, an SV message with a sampling rate of 256 points/week, an SV message with a sampling rate of 80 points/week, an MMS message, and a time-based message. The method for avoiding collision of data packets in a communication network in a substation according to claim 3, wherein the data message priority mechanism is divided into eight priority queues, 7 being the highest priority, and sequentially decreasing, the substation The priority of the service packet is defined as follows: the priority queue number of the fast GOOSE packet is 7, the priority queue number of the regular GOOSE packet is 6, and the priority queue number of the SV packet with a sampling rate of 256 points/week is 5. The sampling rate is The priority queue number of the 80-point/week SV packet is 4, the priority queue number of the MMS packet is 3, and the priority queue number of the timing packet is 2. The method for avoiding collision of data packets in a communication network in a substation according to claim 1 or 2 or 3, wherein the data packet multicast management protocol comprises a manual data packet multicast management protocol and an automatic datagram. The multicast management protocol uses the VLAN protocol for manual data packet multicast management and the GMRP protocol for automatic data packet multicast management. The method for avoiding data packet collision in a communication network in a substation according to claim 5, wherein the VLAN protocol is a VLAN standard protocol defined by IEEE 802.1q, and the static multicast mode is configured to include a multicast MAC address and a VLAN. Number and port mode, IEC61850 substation internal communication network, supports up to 4096 VLANs, supports inserting tag headers, deleting tag headers or modifying tag headers in the forwarded message frames, and supports VLAN trunking. The method for avoiding data packet collision in a substation communication network according to claim 5, wherein the GMRP protocol is a GMRP standard protocol defined by IEEE 802.1p, and the maximum number of dynamic multicasts supported is 256. Join Time takes 200ms, Leave Time takes 600ms, and Leave All Time takes 10000ms. The method for avoiding collision of data packets in a communication network in a substation according to claim 3, characterized in that: a fast GOOSE message, a regular GOOSE message, an SV message with a sampling rate of 256 points/week, and a sampling rate. The continuous CSMA strategy is adopted for the SV message of 80 points/week. The continuous CSMA strategy is: when the communication network in the substation is busy or conflicts, the device that wants to send the message continuously monitors, and when there is idle, it can send The MMS message and the time-based message adopt a p-persistent CSMA policy, which is: does not continuously monitor the channel, but waits for a random period of time when the communication network is busy or conflicts in the substation. Δt, the device that wants to send the message sends the message according to the probability of p, and does not send the message according to the probability of q=1-p. The method for avoiding collision of data packets in a communication network in a substation according to claim 3, characterized in that: a fast GOOSE message, a regular GOOSE message, an SV message with a sampling rate of 256 points/week, and a sampling rate. The data packet avoidance conflict algorithm used for the SV message of 80 points/week is CSMA/CP algorithm, the data packet avoidance conflict algorithm used for MMS message is CSMA/CA algorithm, and the time message uses CSMA/CD algorithm.

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