CN102315985B - Time synchronization precision test method for intelligent device adopting IEEE1588 protocols - Google Patents

Abstract

The invention relates to an intelligent device time synchronization accuracy test method using the IEEE1588 protocol. The time tester is used as a master clock to send an IEEE1588 synchronization message to the tested smart device to establish stable time synchronization; Input the switch signal; the time tester and the smart device under test respectively capture the time stamp of the input switch signal, and the smart device under test generates a GOOSE message and sends it to the time tester; the time tester extracts and receives the GOOSE message The time stamp of the switch quantity input of the smart device under test, the absolute value of the difference between the time stamp and the time stamp of the time tester is the time synchronization error of the smart device under test; the present invention utilizes the time tester and adopts the IEEE1588 protocol for time synchronization, when When the switch input signal changes, the time stamp when the switch changes is sent out through the GOOSE message, which ensures the real-time performance of message transmission and improves the test accuracy and real-time performance.

Description

Time Synchronization Accuracy Test Method for Intelligent Device Using IEEE1588 Protocol

technical field

The invention belongs to the field of relay protection automation of electric power engineering, and relates to a method for testing the time synchronization accuracy of an intelligent device using the IEEE1588 protocol.

Background technique

The network structure of the intelligent substation automation system is simple and the nodes are fixed. It is very suitable to adopt the IEEE1588 network time synchronization protocol. Network, the principle is simple, the implementation of the protocol occupies less equipment resources, and the configuration is simple.

The quality of the time synchronization performance of the smart device is obtained by measuring the time synchronization index. IRIG-B, second pulse and other synchronization methods can be accurately tested by oscilloscope or time testing instrument, but IEEE1588 is a network time synchronization protocol, only when the smart device under test has second pulse output, it can be easily tested using IEEE1588 protocol time synchronization accuracy.

Figure 1 and Figure 2 show the principles of the synchronization accuracy test of smart devices using the IEEE1588 protocol. In Fig. 1, the time server uses GPS signal as the time source, and its output second pulse signal is used as the benchmark of the test. When the time server and the smart device under test are stably synchronized, the second pulse signal is obtained from the time server and the smart device under test and input to the oscilloscope or time tester. The difference between the rising edges of the pulse signal is the time synchronization accuracy of the smart device under test. In Figure 2, the time tester itself uses the GPS signal as the time source and has a reference second pulse signal, and then introduces the second pulse of the smart device under test into the tester, and the tester performs a test on the reference second pulse and the second pulse of the device under test By comparison, the time synchronization accuracy of the smart device under test is obtained.

The essence of these two methods is the same, both are based on the principle of second pulse comparison. However, the shortcomings of this method based on the principle of second pulse comparison are also obvious: although the principle of this method is simple and can accurately measure the time accuracy, in practice, most smart devices do not have a second pulse signal output interface, which makes the second pulse The method of comparing principles loses its implementation conditions. Therefore, for smart devices, it is necessary to find a method that does not rely on second pulse comparison to test the accuracy of smart devices.

Contents of the invention

The purpose of the present invention is to provide a smart device time synchronization accuracy test method using the IEEE1588 protocol to solve the time synchronization accuracy test method of the smart device using the IEEE1588 protocol when there is no second pulse output interface.

In order to achieve the above object, the steps of the smart device time synchronization accuracy test method adopting IEEE1588 protocol of the present invention are as follows:

(1) Electrically connect the signal generating equipment with the smart device under test and the time tester respectively, and connect the smart device under test with the time tester by optical fiber;

(2) As the main clock, the time tester sends IEEE1588 synchronization messages to the smart device under test, and the time tester establishes stable time synchronization with the smart device under test;

(3) The signal generating device simultaneously inputs the switching electric signal to the smart device under test and the time tester;

(4) The time tester captures the time stamp of the input switch signal; when the smart device receives the switch input signal, it captures the time stamp of the input switch, and immediately generates a GOOSE message and sends it to the time tester. The GOOSE message includes the time stamp captured by the smart device under test;

(5) The time tester receives the GOOSE message sent by the smart device under test, and extracts the switch input time stamp of the smart device under test in the GOOSE message, and combines the time stamp with the time tester to obtain the switch input time received by itself The absolute value of the difference is the time synchronization error of the smart device under test.

Further, in the step (5), the time tester obtains two time stamps, which are the time stamp of the digital input received by the time tester itself and the time stamp of the smart device under test extracted from the GOOSE message.

The intelligent device time synchronization accuracy test method using the IEEE1588 protocol of the present invention uses a time tester to perform time synchronization using the IEEE1588 protocol, and has a switching value input electrical interface and an Ethernet optical fiber interface. The text sends out the time stamp when the switching value changes, and the GOOSE message is directly mapped to the link layer and the physical layer after passing through the presentation layer, which ensures the real-time performance of message transmission and improves the test accuracy and real-time performance.

Description of drawings

Fig. 1 is a test schematic diagram of the synchronization accuracy of a smart device in the prior art;

Fig. 2 is the test schematic diagram of another kind of smart device synchronization accuracy in the prior art;

Fig. 3 is the test schematic diagram of the synchronization accuracy of the smart device of the embodiment;

Fig. 4 is a schematic diagram of testing the synchronization accuracy of the smart device in another embodiment;

Fig. 5 is a flow chart of the testing method of the embodiment.

Detailed ways

GOOSE is a fast message mechanism proposed by the IEC61850 standard to solve the fast communication requirements of substations, especially the transmission of relay protection trip information. GOOSE messages are directly mapped to the link layer and physical layer after the presentation layer, and the switched Ethernet technology with priority and VLAN marks can be used to ensure the real-time performance of message transmission. This point provides a technical prerequisite for the time synchronization accuracy test of smart devices using the IEEE1588 protocol. the

The test method for the clock synchronization accuracy of smart devices adopted in this patent application can realize the IEEE1588 clock synchronization accuracy test for a class of smart devices by using the existing time tester. The characteristics of this class of smart devices are: Adopt IEEE1588 for time synchronization , does not have a second pulse output interface, but has a switch input electrical interface and an Ethernet optical fiber interface. When the switch input signal changes, the time stamp when the switch changes can be sent out through the GOOSE message.

Fig. 3 is the synchronous accuracy test schematic diagram of the intelligent device adopting IEEE1588 to realize time synchronization according to the embodiment of the present patent application. The intelligent device for testing is connected with the time tester by optical fiber.

First, the time tester acts as the master clock, and the smart device under test acts as the slave clock. The master clock sends a synchronization message to the slave clock. After a suitable period of time, it can be considered that the time synchronization between the smart device under test and the master clock has stabilized. . The signal generating device simultaneously inputs switching electrical signals to the smart device under test and the time tester. The time tester has a high time stamp resolution and can obtain accurate switch input time stamp t ₁ . When the smart device under test receives the digital input signal, it can also capture the accurate digital input time stamp t ₂ , and the smart device under test immediately sends a GOOSE message, which contains the accurate time stamp t ₂ of the digital input. The time tester receives the GOOSE message sent by the smart device under test, and extracts t ₂ from the GOOSE message. Then the time tester can calculate the time error | t ₁ - t of the test of the smart device by comparing the time stamp t ₁ received by itself with the time stamp t ₂ extracted from the GOOSE message ₂ |.

As shown in Figure 5, the specific flow of the test method of this embodiment is as follows:

S1. Set up the test environment: connect the signal generating equipment to the smart device under test and the time tester respectively, and connect the smart device under test to the time tester through optical fiber; Establish a stable time synchronization with the smart device under test;

S2. The signal generating device simultaneously inputs the switching electric signal to the smart device under test and the time tester;

S3. The time tester has high time stamp resolution and captures the time stamp of the accurate switch input electrical signal;

S4. When the smart device under test receives the digital input signal, it can capture the accurate digital input time stamp, and immediately generate a GOOSE message and send it to the time tester. The GOOSE message contains the accurate time stamp captured by the smart device ;

S5, the time tester receives the GOOSE message, and extracts the switching value input timestamp in the GOOSE message;

S6. The time tester obtains two time stamps: the time stamp of the switching value input received by itself and the time stamp extracted from the GOOSE message. The absolute value of the difference between the two time stamps is the test value of the smart device. time synchronization error;

In actual operation, this experiment should be carried out N times, and the maximum value of |t ₁ - t ₂ | is the time synchronization accuracy of the smart device under test using the IEEE1588 protocol.

Fig. 4 is the test schematic diagram of another embodiment of the present patent application, compared with Fig. 3, the time tester itself outputs the switch output signal, and this switch output signal is input to the time tester and the intelligent device under test simultaneously, simultaneously The smart device under test is connected with the time tester by optical fiber. In this embodiment, the function of the signal generating device is integrated into the time tester, so no separate signal generating device is needed, but the testing process is the same as that of the first embodiment.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. adopt an intelligent apparatus timing tracking accuracy method of testing for IEEE1588 agreement, it is characterized in that, the step of the method is as follows:

(1) be electrically connected with tested intelligent apparatus, time tester respectively by signal generating apparatus, tested intelligent apparatus is connected with optical fiber solutions with time tester;

(2) time tester is as master clock, and tested intelligent apparatus, as from clock, sends IEEE1588 sync message by time tester to tested intelligent apparatus, and it is synchronous that time tester and tested intelligent apparatus set up stabilization time;

(3) signal generating apparatus is to tested intelligent apparatus and the time tester input switch amount signal of telecommunication simultaneously;

(4) time tester catches the timestamp of the switching value signal of telecommunication of input; When tested intelligent apparatus receives the On-off signal signal of telecommunication, catch the switching value timestamp of input, and generation GOOSE message sends to time tester immediately, comprises the switching value timestamp that tested intelligent apparatus is caught in described GOOSE message;

(5) time tester receives the GOOSE message that tested intelligent apparatus sends, and the tested intelligent apparatus On-off signal timestamp extracted in GOOSE message, this tested intelligent apparatus On-off signal timestamp and time tester are obtained the On-off signal timestamp self received do difference obtain a difference, the absolute value of this difference is exactly the time synchronization error of tested intelligent apparatus; Solve the timing tracking accuracy test problem of tested intelligent apparatus when not having pulse per second (PPS) output interface.

2. the intelligent apparatus timing tracking accuracy method of testing of employing IEEE1588 agreement according to claim 1, it is characterized in that: in described step (5), time tester obtains two timestamps, is respectively the On-off signal timestamp that time tester self receives and the tested intelligent apparatus On-off signal timestamp extracted from GOOSE message.