Clock difference measuring method and system based on step-by-step relay of messages

Abstract

The invention relates to a clock error measurement method and system based on message step-by-step relay, and the method comprises the steps: a clock device sends a clock error query message to a tested device, and the tested device carries out the configuration in order to form a step-by-step relay transmission network; the first tested equipment in the step-by-step relay transmission network sends reply messages containing clock difference data to the second tested equipment in sequence; other tested devices except the first tested device and the last tested device send reply messages to the next tested device in sequence, wherein the reply messages comprise the received content of the reply messages sent by the last device and clock difference data of the reply messages; the last tested device sends a reply message containing the content of the received reply message and the clock difference data of the last tested device to the clock device; and the clock device sequentially analyzes the received reply messages to correspondingly obtain the clock difference data of all the tested equipment in the step-by-step relay transmission network. The invention can reduce the quantity of messages received by the clock device.

Description

Technical Field

[0001] The invention relates to a clock difference measurement method and system based on message relay, belonging to the field of power system and communication. Background Art

[0002] At present, the known method for measuring clock error of secondary process layer equipment in power system is to send and receive GOOSE (Generic Object Oriented Substation Event) messages to the equipment under test (process layer equipment) in a unified manner. The data structure is as follows: Figure 1 As shown in the figure, the measuring device sends a query message uniformly, which contains the query status word of all the devices under test, and then receives the reply message of each device under test one by one to analyze the clock error data. The structure of sending and receiving GOOSE messages is as follows: Figure 2 As shown in the figure, after receiving the GOOSE query message, the devices under test read their own query status words and reply a GOOSE message to the measuring device. The measuring device calculates the clock error data of the device under test through the message time stamp. A typical substation secondary system is configured with about 70 process layer devices. The clock device needs to receive and process 70 sets of GOOSE information at the same time. At the same time, the clock device also needs to measure the clock error of about 80 bay layer devices in the whole station through NTP (Network Time Protocol). The communication processing pressure of the clock device is large and the overall performance is low.

[0003] A Chinese patent document with publication number CN114256970A discloses an online monitoring method for clock synchronization of smart substations. In this method, the GOOSE time scale is used to measure the clock difference of the process layer, and the time status measurement software is integrated in the clock device according to the latest specification requirements. When polling is required, the clock device initiates a request and configures a virtual remote control point on the process layer device under test. After the device under test receives it, it returns a virtual remote signal, which is received by the clock device through the timestamp registered by itself when the virtual remote signal is received and the sending timestamp in the returned GOOSE message. The clock device of this method needs to simultaneously receive the GOOSE information sent to the clock device by each process layer device to be measured in the substation system, resulting in high communication processing pressure on the clock device. Summary of the invention

[0004] The purpose of the present invention is to provide a clock error measurement method and system based on message relay, so as to solve the problem of excessive communication pressure when the clock device measures the clock error of process layer equipment in the substation system.

[0005] To achieve the above object, the solution of the present invention includes: A clock difference measurement method based on message relay comprises the following steps: 1) The clock device sends a clock error query message to the device under test, and the device under test is configured in sequence to form a step-by-step relay transmission network; 2) The first device under test in the relay transmission network sends a reply message containing clock error data to the second device under test in sequence; 3) In the relay transmission network, except for the first device under test and the last device under test, the other devices under test send a reply message containing the content of the reply message sent by the previous device and its own clock difference data to the next device under test in sequence; 4) The last device under test in the relay transmission network sends a reply message containing the content of the received reply message and its own clock error data to the clock device; 5) The clock device sequentially parses the received reply messages, thereby obtaining the corresponding clock difference data of all the devices under test in the step-by-step relay transmission network.

[0006] Furthermore, the clock error data includes the time when the device under test receives the clock error query message and the time when it sends the reply message.

[0007] Furthermore, after all the devices under test are networked into A and B networks respectively through switches, the devices under test in A and B networks are configured in sequence to form a step-by-step relay transmission network. The clock device receives the reply message from the last device under test in A and B networks respectively and parses them to obtain the clock difference data of all the devices under test in A and B networks respectively.

[0008] The present invention provides a clock difference measurement system based on message relay, including tested devices configured in sequence to form a relay transmission network and a clock device for sending clock difference query messages to the tested devices and parsing received reply messages; the tested devices include a first tested device for sending a reply message containing clock difference data to a second tested device, a last tested device for sending a reply message containing the content of the received reply message and its own clock difference data to the clock device, and other tested devices except the first tested device and the last tested device for sending a reply message containing the content of the received reply message sent by the previous device and its own clock difference data to the next tested device in sequence.

[0009] Furthermore, the clock error data includes the time when the device under test receives the clock error query message and the time when it sends the reply message.

[0010] Furthermore, after all the devices under test are networked into A and B networks respectively through switches, the devices under test in A and B networks are configured in sequence to form a step-by-step relay transmission network. The clock device receives the reply message from the last device under test in A and B networks respectively and parses them to obtain the clock difference data of all the devices under test in A and B networks respectively.

[0011] The beneficial effects of the present invention are: The present invention is an improved invention. In the present invention, the clock error reply message of the device under test at the process layer is not sent directly to the clock device. It is first relayed and summarized step by step in a hand-in-hand manner between the process layer devices. The last-level device collects the clock error reply data of all process layer devices in the whole station to form a frame of GOOSE message and sends it to the clock device. Without modifying or adding equipment or modifying the communication protocol, the amount of GOOSE messages received by the clock error measurement device is greatly reduced, the comprehensive performance of the clock measurement device is improved, and the operational stability of the clock measurement device is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the data interaction architecture of the prior art; Figure 2 It is a schematic diagram of the structure of receiving and sending GOOSE messages in the prior art; Figure 3 It is a schematic diagram of the step-by-step relay transmission network for sending and receiving GOOSE messages; Figure 4 This is a schematic diagram of the clock difference measurement reply message structure. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0014] The idea of ​​the present invention is to provide a clock difference measurement method and system based on message relay at each level. The clock difference reply message of the device under test at the process layer is not sent directly to the clock device, but is first relayed and summarized at each level by hand in hand between the process layer devices. The last level device collects the clock difference reply data of all process layer devices in the whole station to form a frame of GOOSE message and sends it to the clock device. The number of GOOSE data that the clock device needs to receive and process is sharply reduced, thereby greatly reducing the communication processing pressure of the clock device and improving the overall performance of the device.

[0015] Method Example: The clock error measurement method based on message relay comprises the following steps: 1) Constructing a process layer clock error reply GOOSE message relay transmission network: Figure 3As shown, the process layer devices under test in the existing network are numbered, and a step-by-step relay network is formed by configuring GOOSE transmission and reception in the order of device numbers from small to large; 2) Redefine the clock error measurement reply message structure: Figure 4 As shown in the figure, different numbered devices use different message structures according to their own numbers. The message of device 1 (device number 1) includes the receiving time and sending time of the GOOSE message. The message of device 2 (device number 2) includes the message content of device number 1 and the time when it receives and sends the message. The same goes for the last device under test (the device with the largest number) including the message content of all the previous devices and the time when it receives and sends the message. 3) The clock device sends a GOOSE clock error query message to the process layer device under test; 4) The GOOSE transceiver connection is configured between the devices under test at the process layer according to their numbers: the message structure is as shown in step 2). Device 1 sends a GOOSE reply message to device 2, which contains 2 clock difference data of device 1 (the time of receiving the GOOSE clock difference query message and sending the reply message). After receiving the clock difference data of device 1, device 2 frames the clock difference data of device 1 and its own clock difference data (the clock difference data of device 2) and sends a GOOSE reply message to device 3. The message contains 4 clock difference data of devices 1 and 2. After receiving the clock difference data of device 2, device 3 sends a GOOSE reply message to device 4. The message contains 6 clock difference data of devices 1, 2 and 3. The clock difference messages are relayed step by step in this way. The last device with a number summarizes the clock difference data of all devices in the entire network and sends a frame of GOOSE reply message to the clock device. 5) The clock device receives the GOOSE message from the device with the largest number, and sequentially parses and processes the clock difference data in the message, thereby obtaining the corresponding clock difference data of the process layer devices of the entire station.

[0016] At present, the process layer of the substation is generally networked by A and B networks through switches, and steps 1) to 4 are performed on the devices under test in A and B networks respectively. The clock device receives two GOOSE messages from the device with the largest number in process layer A network and the device with the largest number in B network respectively, and then parses and processes the clock difference data in the messages in sequence to obtain the clock difference data of all process layer devices in A and B dual networks.

[0017] System Example: This embodiment provides a clock error measurement system based on message relay. Figure 3As shown, the process layer devices under test are relayed hand in hand, and the last level device collects the clock difference data of all process layer devices in the whole station to form a GOOSE message and send it to the clock device. The clock device then parses the clock difference data in the message in sequence, thereby obtaining the corresponding clock difference data of the process layer devices under test in the whole station.

[0018] The devices under test are configured with GOOSE transmission and reception in ascending order to form a relay transmission network. After the clock device sends a GOOSE clock error query message to all the devices under test in the network, the devices under test use different message structures to send reply messages according to their order in the network, such as Figure 4 As shown in the figure, device No. 1 sends a GOOSE reply message to device No. 2, and the message contains 2 clock difference data of device No. 1 (the time of receiving the GOOSE clock difference query message and sending the reply message); after receiving the clock difference data of device No. 1, device No. 2 frames the clock difference data of device No. 1 and its own clock difference data (the clock difference data of device No. 2) and sends a GOOSE reply message to device No. 3, and the message contains 4 clock difference data of devices No. 1 and No. 2; after receiving the clock difference data of device No. 2, device No. 3 sends a GOOSE reply message to device No. 4, and the message contains 6 clock difference data of devices No. 1, No. 2 and No. 3. In this way, the clock difference messages are relayed and transmitted step by step. The last numbered device summarizes the clock difference data of all devices in the entire network and sends a frame of GOOSE reply message to the clock device; the clock device receives the GOOSE message of the device with the largest number, and sequentially parses and processes the clock difference data in the message, so as to obtain the corresponding clock difference data of the process layer devices of the entire station.

[0019] At present, the process layer of the substation is generally networked according to the A and B networks through switches. The tested devices in the A and B networks are configured to form a step-by-step relay transmission network and the GOOSE transceiver connection is configured. During the clock difference test, the clock device receives two GOOSE messages from the device with the largest number in the process layer A network and the device with the largest number in the B network. Then, the clock difference data in the message is analyzed and processed in sequence to obtain the clock difference data of all process layer devices in the A and B dual networks.

Claims

1. A clock error measurement method based on message relay, characterized in that: The following steps are involved: 1) The clock device sends a clock error query message to the device under test, and the device under test is configured in sequence to form a step-by-step relay transmission network; 2) The first device under test in the relay transmission network sends a reply message containing clock error data to the second device under test in sequence; 3) In the relay transmission network, except for the first device under test and the last device under test, the other devices under test send a reply message containing the content of the reply message sent by the previous device and its own clock difference data to the next device under test in sequence; 4) The last device under test in the relay transmission network sends a reply message containing the content of the received reply message and its own clock error data to the clock device; 5) The clock device sequentially parses the received reply messages, thereby obtaining the corresponding clock difference data of all the devices under test in the step-by-step relay transmission network.

2. The clock error measurement method based on message relay according to claim 1 is characterized in that: The clock error data includes the time when the device under test receives the clock error query message and the time when the device under test sends a reply message.

3. The clock error measurement method based on message relay according to claim 1 is characterized in that: After all the devices under test are networked into A and B networks respectively through switches, the devices under test in A and B networks are configured in sequence to form the step-by-step relay transmission network. The clock device receives the reply message from the last device under test in A and B networks respectively and parses them to obtain the clock difference data of all the devices under test in A and B networks respectively.

4. A clock error measurement system based on message relay, characterized in that: It includes devices under test that are sequentially configured to form a step-by-step relay transmission network and a clock device that sends clock difference query messages to the devices under test and parses received reply messages; the devices under test include a first device under test that sends a reply message containing clock difference data to a second device under test, a last device under test that sends a reply message containing the content of the received reply message and its own clock difference data to the clock device, and other devices under test except the first device under test and the last device under test that send a reply message containing the content of the received reply message sent by the previous device and its own clock difference data to the next device under test in sequence.

5. The clock error measurement system based on message relay according to claim 4 is characterized in that: The clock error data includes the time when the device under test receives the clock error query message and the time when the device under test sends a reply message.

6. The clock error measurement system based on message relay according to claim 4 is characterized in that: After all the devices under test are networked into A and B networks respectively through switches, the devices under test in A and B networks are configured in sequence to form the step-by-step relay transmission network. The clock device receives the reply message from the last device under test in A and B networks respectively and parses them to obtain the clock difference data of all the devices under test in A and B networks respectively.

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