An on-line monitoring device for the performance degradation test of an optical fiber link used in nuclear power

Abstract

The present invention belongs to the technical field of performance degradation test of optical fiber devices, and particularly relates to an on-line monitoring device for performance degradation test of optical fiber link used in nuclear power. It includes a minimization module of nuclear power distributed control system, an optical signal transmission link module, an optical signal conversion module and a host computer workstation. The minimization module of nuclear power distributed control system is connected to the optical signal transmission link module through an LC / LC optical fiber connector. The optical signal transmission link module is connected to the optical signal conversion module through an ST / LC. The optical signal conversion module is connected to the host computer workstation through a network cable. The host computer workstation is connected to the minimization module of nuclear power distributed control system through a network cable. The beneficial effect of the present invention lies in: combining the optical fiber usage environment at the nuclear power DCS site, changing the aging test object from the traditional optical fiber jumper to all components on the whole optical fiber link, making the test conclusion more representative.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber optic device performance degradation testing, and particularly relates to an on-line monitoring device for performance degradation testing of a fiber optic link used in nuclear power plants. Background Art

[0002] Optical fibers and fiber optic connectors are widely used in various application environments due to their advantages such as large communication capacity, low signal interference, electromagnetic interference resistance, no radiation, small size, light weight, and long lifespan. Optical fibers have also been widely used in nuclear power DCS equipment. Mainstream domestic DCS manufacturers all use optical fibers to achieve communication functions within and between DCS cabinets. However, their disadvantages such as brittleness, poor mechanical strength, inability to have too small a bending radius, and easy damage to the optical end face can also cause a decline in transmission quality and even interruption of transmission. Therefore, it is of great practical significance to study the performance degradation and aging mechanism of fiber optic devices.

[0003] Traditional optical fiber aging test methods perform environmental stress aging tests on optical fiber specimens. Before the test, the insertion loss and return loss of the optical fiber to be measured are detected by instruments. After performing a series of aging tests such as high-temperature aging and temperature cycling, the insertion loss and return loss of the optical fiber are detected again. This testing method has the following disadvantages:

[0004] 1. Other components on the fiber optic link are not considered, and the on-site environment of fiber optic applications is separated. Generally, optical fibers need to be combined with other components, such as fiber optic adapters, optoelectronic converters, optical modules, etc., to form a fiber optic link to achieve signal transmission functions. Traditional optical fiber aging test methods only perform aging tests on optical fibers and do not consider other functional components on the fiber optic link.

[0005] 2. The aging performance of the optical fiber is detected offline, and only the performance degradation data of the optical fiber before and after the test can be obtained. It is difficult to obtain the process data of the optical fiber performance degradation, and it is impossible to establish an accurate mathematical model of the optical fiber performance degradation over time.

[0006] 3. It is difficult to determine the loss threshold when the optical fiber degrades to unusable in the actual application scenario. The loss threshold when the optical fiber degrades to unusable is different in different application scenarios. Traditional test methods cannot obtain the loss threshold when the optical fiber degrades to unusable in a specific application scenario.

[0007] Existing optical fiber aging test methods focus on studying the performance degradation of optical fibers before and after aging tests, do not consider the impact of the aging of other components on the fiber optic link on signal transmission performance, and it is difficult to determine the loss threshold when the optical fiber degrades to unusable in the actual application scenario. Summary of the Invention

[0008] The object of the present invention is to provide an on-line monitoring device for the performance degradation test of an optical fiber link for nuclear power, which can on-line monitor in real time the performance degradation data of the optical fiber link during the execution of the aging test, obtain the loss threshold when the optical fiber degrades to inoperability in the actual application scenario, and provide a basis for the preventive maintenance of optical fiber components at the nuclear power site.

[0009] The technical solution of the present invention is as follows: An on-line monitoring device for the performance degradation test of an optical fiber link for nuclear power includes a nuclear power distributed control minimization system, an optical signal transmission link module, an optical signal conversion module, and a host computer workstation. The nuclear power distributed control minimization system is connected to the optical signal transmission link module through an LC / LC optical fiber connector. The optical signal transmission link module is connected to the optical signal conversion module through an ST / LC. The optical signal conversion module is connected to the host computer workstation through a network cable. The host computer workstation is connected to the nuclear power distributed control minimization system through a network cable.

[0010] The nuclear power distributed control minimization system includes an AC / DC power conversion module, two optoelectronic conversion modules, and two DCS main controllers. Its function is to simulate the actual communication signal data generated by the nuclear power DCS, convert it into a standard optical signal, and then inject the optical signal into the transmission link.

[0011] The function of the AC / DC power conversion module is to convert the external 220V alternating current into 42V direct current, which serves as the working power supply for the optoelectronic conversion module and the DCS main controller card. A minimized control program runs in the DCS main controller, providing a continuous and stable network signal value consistent with the nuclear power site for the optoelectronic conversion module. Inside the control program of the DCS main controller, a fixed reactor primary loop average temperature value and a reactor electric power value are generated by a fixed data generation module and transmitted to the output module. The self-diagnosis module built in the DCS main controller judges the working condition of the DCS main controller in real time, generates a signal quality code, and transmits it to the output module. The clock module built in the DCS main controller generates a real-time time signal and transmits it to the output module. The output module transmits the above signal values to the optoelectronic conversion module through the optical fiber link system.

[0012] The optical signal transmission link module includes an optical signal transmission link system composed of a splitter, an optical fiber connector, an optical fiber splicing box, and an optical cable. The two optoelectronic conversion modules of the nuclear power distributed control minimization system are respectively connected to the splitter through LC / LC optical fiber connectors. The splitter is connected to the optical fiber splicing box through an ST / LC optical fiber connector. The optical fiber splicing box is connected to another optical fiber splicing box through an optical fiber. The optical fiber splicing box is connected to the optical signal conversion module through an ST / LC optical fiber connector.

[0013] The optical signal transmission link module is placed as a whole aging object in a high-temperature and high-humidity aging test chamber.

[0014] The described optical signal conversion module includes an optical module and a switch. The optical module is installed on the optical module interface of the switch. The switch converts the optical signal into a network signal and simultaneously monitors the power of the optical signal received by the optical module.

[0015] The described upper computer workstation is installed with a test data analysis system.

[0016] The described test data analysis system includes test data analysis software running on the upper computer workstation. The test data analysis software includes a time series database, a data analysis and processing program, and a human-machine interface. The time series database receives in real-time the true nuclear power process signal values sent by the nuclear power distributed control minimization system to the optical fiber link, the optical signal power data sent by the optical module, and the communication signal data values sent by the switch. These data values are recorded in the time series database at a frequency of 10 Hz. The data analysis and processing program reads the data in the time series database in real-time, subtracts the true value from the transmission value to obtain Result 1, takes the absolute value of Result 1 to obtain Result 2, divides Result 2 by the true value to obtain Result 3. If Result 3 does not exceed 5%, it is considered that the deviation between the true value and the transmission value is within the allowable range, and the optical fiber link transmits signals normally; if Result 3 exceeds 5%, it is considered that the deviation between the true value and the transmission value exceeds the allowable range, and the optical fiber link transmits signals abnormally.

[0017] The beneficial effects of the present invention are as follows: 1. Combining with the optical fiber usage environment at the nuclear power DCS site, changing the aging test object from traditional optical fiber jumpers to all components on the entire optical fiber link, making the test conclusion more representative. 2. Using the method of online monitoring of optical fiber aging parameters to obtain the optical fiber performance degradation data during the test and establish a mathematical model for the degradation of the optical fiber link performance over time. 3. Determining the loss threshold when the optical fiber degrades to unusable in the actual application scenario through tests. Description of the Drawings

[0018] Figure 1 It is an architecture diagram of an online monitoring device for the performance degradation test of an optical fiber link for nuclear power provided by the present invention;

[0019] Figure 2 It is a function diagram of the minimization control program running in the DCS main controller;

[0020] Figure 3 It is a function diagram of the test data analysis system installed on the upper computer workstation;

[0021] Figure 4 It is a processing function flow chart of the data analysis and processing program;

[0022] Figure 5 It is the image after fitting the example of the present invention. Detailed Implementation Modes

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0024] As Figure 1 shown, an on-line monitoring device for the performance degradation test of an optical fiber link for nuclear power includes a minimization module of a nuclear power distributed control system, an optical signal transmission link module, an optical signal conversion module, and a host computer workstation. The minimization module of the nuclear power distributed control system is connected to the optical signal transmission link module through an LC / LC fiber optic connector. The optical signal transmission link module is connected to the optical signal conversion module through an ST / LC. The optical signal conversion module is connected to the host computer workstation through a network cable. The host computer workstation is connected to the minimization module of the nuclear power distributed control system through a network cable.

[0025] The minimization module of the nuclear power distributed control system includes an AC / DC power conversion module, two optoelectronic conversion modules, and two DCS main controller cards. Its function is to simulate the actual communication signal data generated by the nuclear power DCS and convert it into a standard optical signal, and then inject the optical signal into the transmission link. Among them, the function of the AC / DC power conversion module is to convert external 220V alternating current into 42V direct current as the working power supply for the optoelectronic conversion module and the DCS main controller card. A minimized control program runs in the DCS main controller, and its main function is to provide a continuous and stable network signal value consistent with the nuclear power site for the optoelectronic conversion module. The functional diagram of the minimized control program running in the DCS main controller card is as Figure 2 shown. Inside the control program, a fixed reactor primary loop average temperature value and a reactor electric power value are generated by a fixed data generation module and transmitted to the output module. The self-diagnosis module built in the DCS main controller continuously judges the working condition of the DCS main controller and generates a signal quality code and transmits it to the output module. The clock module built in the DCS main controller generates a real-time time signal and transmits it to the output module. The output module transmits the above signal values to the optoelectronic conversion module through the optical fiber link system. The optoelectronic conversion module converts the optical signal into a communication signal and transmits it to the switch. The test data analysis system running on the workstation continuously receives the real nuclear power process signal sent by the nuclear power distributed control minimization system to the optical fiber link, the optical signal power signal sent by the optical signal conversion module, and the communication signal sent by the switch.

[0026] The optical signal transmission link module includes an optical signal transmission link system composed of a splitter, a fiber optic connector, a fiber optic splicing box, and an optical cable. The two optoelectronic conversion modules of the minimization module of the nuclear power distributed control system are respectively connected to the splitter through LC / LC fiber optic connectors. The splitter is connected to the fiber optic splicing box through an ST / LC fiber optic connector. The fiber optic splicing box is connected to another fiber optic splicing box through an optical fiber. The fiber optic splicing box is connected to the optical signal conversion module through an ST / LC fiber optic connector. The optical signal transmission link module is placed as a whole aging object in a high-temperature and high-humidity aging test chamber.

[0027] The optical signal conversion module includes an optical module and a switch. The optical module is installed on the optical module interface of the switch. The switch converts the optical signal into a network signal and monitors the power of the optical signal received by the optical module.

[0028] A test data analysis system is installed on the host computer workstation, and its functional diagram is as Figure 3 shown. The test data analysis system includes test data analysis software. The test data analysis software runs in the host computer workstation. The test data analysis software includes a time series database, a data analysis and processing program, and a human-machine interface. The time series database receives in real time the true nuclear power process signal values (hereinafter referred to as DCS signals) sent by the nuclear power distributed control minimization system to the optical fiber link, the optical signal power data (hereinafter referred to as optical power signals) sent by the optical signal conversion module, and the communication signal data values (hereinafter referred to as switch signals) sent by the switch. These data values are recorded in the time series database at a frequency of 10 Hz. The data analysis and processing program reads the data in the time series database in real time, subtracts the transmitted value from the true value to get result 1, takes the absolute value of result 1 to get result 2, divides result 2 by the true value to get result 3. If result 3 does not exceed 5%, it is considered that the deviation between the true value and the transmitted value is within the allowable range, and the optical fiber link transmits signals normally; if result 3 exceeds 5%, it is considered that the deviation between the true value and the transmitted value exceeds the allowable range, and the optical fiber link transmits signals abnormally. And perform difference and absolute value calculations on the DCS signal data values and the switch signal data values, and then divide the calculation result by the DCS signal data value at this time. If the calculation result does not exceed 5%, it is considered that the deviation between the DCS signal data value and the switch signal data value is within the allowable range, and the optical fiber link transmits signals normally; if the calculation result exceeds 5%, it is considered that the deviation between the DCS signal data value and the switch signal data value exceeds the allowable range, and the optical fiber link transmits signals abnormally. The processing function flow chart of the data analysis and processing program is as Figure 4 shown. The human-machine interface displays the DCS signal value, the optical power signal value, and the switch signal value in real time, and provides the start, pause, and stop functions of the test data analysis system program.

[0029] For the communication signal data sent by the minimization module of the nuclear power distributed control system and the communication signal data sent by the switch, the data structure recorded in the time series database is shown in Table 1.

[0030] Table 1 Data structure of process signal data

[0031]

[0032] For the optical power signal data in the signal acquisition function module, the recorded data structure is shown in Table 2.

[0033] Table 2 Data Structure of Optical Power Signal Data

[0034]

[0035] An on-line monitoring method for the performance degradation test of an optical fiber link used in nuclear power, comprising the following steps:

[0036] Step 1: Build a test system as shown in Figure 1 . Place the fiber optic link under test in a high and low temperature test chamber.

[0037] Step 2: The nuclear power decentralized control minimization system sends the real nuclear power process signal value to the fiber optic link. This signal is received by the optical module and the switch after passing through the fiber optic link. At the same time, the optical module can detect the optical power value in the fiber optic link.

[0038] Step 3: The test data processing and analysis system running in the workstation collects and stores the real nuclear power process signal value (hereinafter referred to as the DCS signal) sent by the nuclear power decentralized control minimization system to the fiber optic link, the optical signal power data (hereinafter referred to as the optical power signal) sent by the optical signal conversion module, and the communication signal data value (hereinafter referred to as the switch signal) sent by the switch at a frequency of 10HZ.

[0039] Step 4: The data analysis and processing program calculates the absolute value of the difference between the DCS signal data value and the switch signal data value in real time, and then divides the calculation result by the DCS signal data value at this time. If the calculation result does not exceed 5%, it is considered that the deviation between the DCS signal data value and the switch signal data value is within the allowable range, and the fiber optic link transmits the signal normally; if the calculation result exceeds 5%, it is considered that the deviation between the DCS signal data value and the switch signal data value exceeds the allowable range, and the fiber optic link transmits the signal abnormally. In the test initialization stage, the fiber optic link transmits the signal without loss, and the DCS signal data value and the switch signal data value should be exactly the same. As the fiber optic link ages, the transmission performance decreases. After the deviation between the DCS signal data value and the switch signal data value exceeds 5% for the first time and 1 second later, stop the test. The optical power value at this time is defined as the fiber optic unavailable threshold in the actual application scenario.

[0040] Step 5: After the test is completed, process the test data to obtain the aging relationship model between the fiber optic link and the thermal stress.

[0041] Example 1:

[0042] Build a test system as shown in Figure 1 .

[0043] Confirm the test initial conditions: Connect the 220VAC power supply to the AC / DC power supply module in Module 1, and the DCS main controller card and the optoelectronic conversion module in Module 1 are in normal operating states.

[0044] The tester operates the test control software of the module 4 - host computer workstation to control the nuclear power distributed control minimization system to output the nuclear power plant process signal value.

[0045] The tester confirms in the test control software of the module 4 - host computer workstation that the read nuclear power plant process signal value is consistent with the output value.

[0046] The tester confirms in the test control software of the module 4 - host computer workstation that the read optical signal power value is within the normal range.

[0047] Start the high - temperature test chamber, raise the temperature of the test chamber to 35°C and hold it. The test control software of the host computer workstation continuously records the nuclear power plant process signal value (with quality code), optical signal power value, and read - back time at a frequency of 10HZ.

[0048] Stop the test 1 second after the first deviation of the DCS signal data value and the switch signal data value exceeds 5%. At this time, the collected optical power value is the optical power threshold when the optical link is unavailable.

[0049] During the above - mentioned entire test process, the quality code data value should be ensured to be 1. If the quality code data is 0, it is considered that the CPU is working in an abnormal state and this test is invalid.

[0050] Take out the optical fiber, optical cable, splitter, and fusion box to be tested, and replace them with brand - new ones of the same model. Re - execute the test steps of this embodiment, but before starting the high - temperature test chamber, set the temperature of the test chamber to 45°C, 55°C, 65°C, 75°C, 85°C, and 95°C respectively. Each time the test is re - executed, the object to be tested in the high - temperature chamber needs to be replaced with brand - new ones of the same model of the optical fiber, optical cable, splitter, and fusion box. After the test is completed, the change amount of the optical power at different temperatures is obtained.

[0051] Use the following method to fit the test data to obtain the determined degradation rate. Based on the collected test data, calculate the degradation rate of the optical fiber. The degradation rate can be defined as the change rate of the optical power with time, that is: Degradation rate , where ΔP is the change amount of the optical power and ΔT is the change amount of time.

[0052] Linear fitting. Use the Arrhenius equation to describe the change trend of the degradation rate k(T) with temperature T:

[0053] (1)

[0054] Where: k(T) is the degradation rate at temperature T, A is the frequency factor, Ea is the activation energy, k Bis the Boltzmann constant, and T is the thermodynamic temperature (Kelvin).

[0055] Take the logarithm of Equation (1) and convert it into a linear equation (2):

[0056] (2)

[0057] Select as the independent variable, as the dependent variable, and use the polyfit function in the MATLAB software for linear fitting based on the test results to determine the frequency factor A and the activation energy Ea, and obtain the functional relationship between the degradation rate and the working environment temperature.

[0058] Example 2:

[0059] According to Figure 1 shown, build the test system.

[0060] Confirm the test initial conditions: Connect the 220VAC power supply to the AC / DC power supply module in Module 1, and the DCS main controller card and the optoelectronic conversion module in Module 1 work in the normal operating state. In this example, the normal operating state is defined as the power light of the DCS main controller card and the optoelectronic conversion module being on and the fault light being off.

[0061] The test personnel operate the test control software of Module 4 - the upper computer workstation to control the nuclear power distributed control minimization system to output the nuclear power plant process signal value. In this example, the nuclear power plant process signal value can be defined as the average temperature of the primary loop of the reactor: 300.5°C and the reactor thermal power: 1100.5MW.

[0062] The test personnel confirm in the test control software of Module 4 - the upper computer workstation that the read nuclear power plant process signal value is consistent with the output value and the quality code is 1. In this example, the read nuclear power plant process signal value is the average temperature of the primary loop of the reactor: 300.5°C and the reactor electric power: 1100.5MW, and the read quality code is 1.

[0063] The test personnel confirm in the test control software of Module 4 - the upper computer workstation that the read optical signal power value is within the normal range. In this example, the normal range refers to between -10dbm and -50dbm.

[0064] Start the high-temperature test chamber, raise the temperature of the test chamber to 308.15K and keep it. The test control software of the upper computer workstation continuously records the nuclear power plant process signal value (with quality code), the optical signal power value, and the read time at a frequency of 10HZ. The test start time is recorded as 1ms, and data is recorded every 100ms thereafter.

[0065] Stop the test 1 second after the first deviation of the DCS signal data value and the switch signal data value exceeds 5%. The optical power value collected at this time is the optical power threshold when the optical link is unavailable. In this example, some of the recorded data is shown in Table 3 below. At 1394757000 milliseconds, the deviation of the DCS signal data value and the switch signal data value first exceeds 5%. The test stops 1 second later. The optical power value collected at this time is -25.3 dbm, which is the optical power threshold when the optical link is unavailable.

[0066] Table 3 Test data at an aging temperature of 308.15K

[0067]

[0068] Take out the optical fiber, optical cable, splitter, and fusion box to be tested, and replace them with brand-new ones of the same model. Re-execute the test steps of this embodiment, but the temperature of the test chamber needs to be set to 318.15K, 328.15K, 338.15K, 348.15K, 358.15K, and 368.15K respectively during the temperature adjustment process before starting the high-temperature test chamber. Each time the test is re-executed, the object to be tested in the high-temperature chamber needs to be replaced with brand-new ones of the same model. After the test is completed, the change in optical power at different temperatures is obtained.

[0069] Use the following method to fit the test data to obtain the functional relationship between the degradation rate and the working environment temperature.

[0070] Determine the degradation rate K. Based on the collected test data, calculate the degradation rate of the optical fiber by the linear fitting method. Take the obtained time t as the independent variable, the optical signal power value P as the dependent variable, the degradation rate as K, and the linear fitting deviation as B. Use the polyfit function of Matlab software to perform a first-order linear fitting. In this example, according to the obtained data, using the linear fitting method, at an aging temperature of 35°C, the degradation rate K1 = -0.75*10 -5 dbm / s. According to the obtained data, at aging temperatures of 45°C, 55°C, 65°C, 75°C, 85°C, and 95°C, the degradation rates are as shown in Table 4 below:

[0071] Table 4 Degradation rates at different aging temperatures

[0072]

[0073] Use the Arrhenius equation to describe the change trend of the degradation rate k(T) with temperature T:

[0074] (1)

[0075] Where: k(T) is the degradation rate at temperature T, A is the frequency factor, Ea is the activation energy, k B is the Boltzmann constant, k B = 1.38 * 10 -23 J / K. T is the thermodynamic temperature (in Kelvin).

[0076] Taking the logarithm of Equation (1) and converting it to a linear equation (2):

[0077] (2)

[0078] According to the requirements of Equation (2), transform the data in Table 4, transform the temperature T (in Kelvin) into , and transform into to obtain Table 5 below

[0079] Table 5 Degradation Rates at Different Aging Temperatures

[0080]

[0081] Select as the independent variable, as the dependent variable, and use the polyfit function in MATLAB software for linear fitting based on the test results. In this example, the fitted image is shown in Figure 5 . According to the fitted parameters, the variation trend of the degradation rate k(T) with temperature T is as shown in Equation (3).

[0082] (3)

[0083] According to Equation (3), the degradation rate of the optical transmission link at other operating environment temperatures can be calculated, the frequency factor A and the activation energy Ea can be determined, and the functional relationship between the degradation rate and the operating environment temperature can be obtained.

Claims

1. An on-line monitoring device for the performance degradation test of an optical fiber link used in nuclear power, characterized in that: It includes a nuclear power decentralized control minimization system, an optical signal transmission link module, an optical signal conversion module, and a host computer workstation. The nuclear power decentralized control minimization system is connected to the optical signal transmission link module through an LC / LC fiber optic connector. The optical signal transmission link module is connected to the optical signal conversion module through an ST / LC. The optical signal conversion module is connected to the host computer workstation through a network cable. The host computer workstation is connected to the nuclear power decentralized control minimization system through a network cable. A test data analysis system is installed on the host computer workstation. The optical signal conversion module includes an optical module and a switch. The test data analysis system includes test data analysis software running on the host computer workstation. The test data analysis software includes a time series database, a data analysis and processing program, and a human-machine interface. The time series database receives in real time the true nuclear power process signal values sent by the nuclear power decentralized control minimization system to the optical fiber link, the optical signal power data sent by the optical module, and the communication signal data values sent by the switch. These data values are recorded in the time series database at a frequency of 10 Hz. The data analysis and processing program reads the data in the time series database in real time, subtracts the nuclear power process signal value from the communication signal data value to obtain result 1, takes the absolute value of result 1 to obtain result 2, divides result 2 by the nuclear power process signal value to obtain result 3. If result 3 does not exceed 5%, it is considered that the deviation between the nuclear power process signal value and the communication signal data value is within the allowable range, and the optical fiber link transmits signals normally. If result 3 exceeds 5%, it is considered that the deviation between the nuclear power process signal value and the communication signal data value exceeds the allowable range, and the optical fiber link transmits signals abnormally. At this time, the optical signal power value is defined as the optical fiber unavailable threshold in the actual application scenario.

2. The on-line monitoring device for the performance degradation test of the optical fiber link used in nuclear power as described in claim 1, wherein: The nuclear power decentralized control minimization system includes an AC / DC power conversion module, two optoelectronic conversion modules, and two DCS master controllers. Its function is to simulate the actual communication signal data generated by the nuclear power DCS and convert it into a standard optical signal, and then inject the optical signal into the transmission link.

3. The on-line monitoring device for the performance degradation test of the optical fiber link used in nuclear power as described in claim 2, wherein: The function of the AC / DC power conversion module is to convert external 220V alternating current into 42V direct current, which serves as the working power supply for the optoelectronic conversion module and the DCS master controller card. A minimized control program runs in the DCS master controller, providing a nuclear power process signal value consistent with the nuclear power site for the optoelectronic conversion module. Inside the control program of the DCS master controller, a fixed reactor primary loop average temperature value and a reactor electric power value are generated by a fixed data generation module and transmitted to the output module. The self-diagnosis module built in the DCS master controller judges the working condition of the DCS master controller in real time and generates a signal quality code and transmits it to the output module. The clock module built in the DCS master controller generates a real-time time signal and transmits it to the output module. The output module transmits the above nuclear power process signal value to the optoelectronic conversion module through the optical fiber link system.

4. The on-line monitoring device for the performance degradation test of the optical fiber link used in nuclear power as described in claim 2, wherein: The described optical signal transmission link module includes an optical signal transmission link system composed of a splitter, an optical fiber connector, an optical fiber splicing box, and an optical cable. Two optoelectronic conversion modules of the nuclear power decentralized control minimization system are respectively connected to the splitter through LC / LC optical fiber connectors. The splitter is connected to the optical fiber splicing box through an ST / LC optical fiber connector. The optical fiber splicing box is connected to another optical fiber splicing box through an optical fiber. The optical fiber splicing box is connected to the optical signal conversion module through an ST / LC optical fiber connector.

5. The on-line monitoring device for the performance degradation test of the optical fiber link used in nuclear power as described in claim 4, characterized in that: The described optical signal transmission link module is placed as a whole aging object in a high-temperature and high-humidity aging test chamber.

6. The on-line monitoring device for the performance degradation test of the optical fiber link used in nuclear power as described in claim 1, characterized in that: The optical module is installed on the optical module interface of the switch. The switch converts the optical signal into a network signal and simultaneously monitors the power of the optical signal received by the optical module.

7. An on-line monitoring method for the performance degradation test of an optical fiber link used in nuclear power, characterized in that, It includes the following steps: Step 1: Build a test system, and place the fiber optic link to be tested in a high and low temperature test chamber; Step 2: The nuclear power decentralized control minimization system sends real nuclear power process signal values to the fiber optic link. After passing through the fiber optic link, the signal is received by the optical module and the switch. At the same time, the optical module can detect the optical power value in the fiber optic link; Step 3: The test data processing and analysis system running in the workstation collects and stores the real nuclear power process signal values sent by the nuclear power decentralized control minimization system to the fiber optic link, the optical signal power data sent by the optical signal conversion module, and the communication signal data values sent by the switch at a frequency of 10HZ; Step 4: The data analysis and processing program calculates the absolute value of the difference between the nuclear power process signal value and the communication signal data value in real time, and then divides the calculation result by the nuclear power process signal value at this time. If the calculation result does not exceed 5%, it is considered that the deviation between the nuclear power process signal value and the communication signal data value is within the allowable range, and the fiber optic link transmits the signal normally; If the calculation result exceeds 5%, it is considered that the deviation between the nuclear power process signal value and the communication signal data value exceeds the allowable range, and the fiber optic link transmits the signal abnormally. In the initial stage of the test, the fiber optic link transmits the signal without loss, and the nuclear power process signal value and the communication signal data value should be exactly the same. As the fiber optic link ages, the transmission performance decreases. After 1 second when the deviation between the nuclear power process signal value and the communication signal data value first exceeds 5%, stop the test. At this time, the optical signal power value is defined as the fiber optic unavailable threshold in the actual application scenario; Step 5: After the test is completed, process the test data to obtain the aging relationship model between the fiber optic link and thermal stress.

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