A method for over-limit temperature protection of hydropower station units

Abstract

The present invention relates to a method for protecting a hydropower station unit from over-temperature. The method optimizes the temperature over-limit judgment process to make the judgment more comprehensive and accurate. The method uses the temperature over-limit status combined with the status of whether the unit's outlet circuit breaker is closed to jointly judge the process for the unit's next action, thereby achieving overall optimization of the temperature over-limit protection method. This method can avoid the risk of tile burning caused by temperature rise and the possibility of abnormal shutdown of the unit caused by sudden temperature changes.

Description

Technical Field

[0001] The present invention relates to the technical field of hydropower generation automation monitoring, and in particular to a method for over-limit temperature protection of a hydropower station unit. Background Art

[0002] In the existing temperature protection configuration of hydropower station units, temperature over-limit protection is usually adopted as follows Figure 1 The method flow shown in the figure collects the real-time temperature of any channel of the unit. When the collected channel i temperature Ti exceeds the over-temperature set value Ti_HH, an over-temperature alarm is triggered for channel i, and the unit temperature protection logic is activated. The over-temperature set value Ti_HH is set based on the unit's bearing position, normal operating conditions, and other factors, and is generally much higher than the unit's normal operating temperature.

[0003] In actual production, after a unit overhaul, the bearing position needs to be adjusted, requiring a test run at idle to test the bearings. This can cause temperature jumps. Even if the temperature jump does not reach the high-alarm threshold, the unit should be shut down immediately and the bearings inspected to prevent further temperature increases and burnout. Furthermore, during normal grid-connected operation, the temperature-measuring RTD element is susceptible to external interference, loose wiring, faulty components, and other factors, leading to signal fluctuations. If the temperature suddenly reaches the high-alarm threshold, it can trigger an unplanned shutdown, impacting normal production safety. Therefore, existing temperature protection methods alone cannot accurately detect all temperature fluctuations in the unit, and further optimization is needed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for temperature over-limit protection of hydropower station units. The method uses the temperature over-limit status combined with the status of whether the unit outlet circuit breaker is closed to jointly judge the next action process of the unit, thereby realizing the overall optimization of the temperature over-limit protection scheme and making the judgment more comprehensive and accurate.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] 1. A method for over-temperature protection of a hydropower station unit, comprising the following steps:

[0007] S1. Set the temperature over-high set value Ti_HH and collect the real-time temperature Ti of the i-th line of the unit.

[0008] S2. Determine whether the temperature of the i-th channel exceeds the limit. If it exceeds the limit, proceed to step S3; if it is normal, proceed to step S4.

[0009] S3. Determine whether the unit outlet circuit breaker is open. If so, start the unit shutdown process. If not, end the determination.

[0010] S4. Determine whether the unit outlet circuit breaker is closed. If so, proceed to step S5; if not, end the determination.

[0011] S5. Determine whether the temperature Ti of the i-th circuit is greater than the over-temperature set value Ti_HH. If so, an over-temperature alarm is triggered and the unit temperature protection logic is entered. If not, the determination is terminated.

[0012] Furthermore, determining whether the temperature of the i-th channel is out of limit includes the following steps:

[0013] S21. Set the temperature over-limit value to Ti_set, perform periodic scanning on the i-th temperature, set the i-th temperature of a certain scanning cycle to Ti_in, set the i-th temperature of the previous scanning cycle to Ti_last, and set the initial temperature of the i-th temperature Ti_in before entering the over-limit state to Ti_in_yx.

[0014] S22. Determine whether the temperature Ti_in of the i-th channel exceeds the limit. If normal, proceed to step S23; if exceeded, proceed to step S24.

[0015] S23. Determine whether Ti_in minus Ti_last is greater than Ti_set. If so, the i-th channel temperature Ti_in exceeds the limit and the process proceeds to step S25. Otherwise, the i-th channel temperature Ti_in is normal and the process proceeds to step S25.

[0016] S24. Determine whether Ti_in minus Ti_in_yx is less than Ti_set. If so, the i-th channel temperature Ti_in has returned to normal and the process proceeds to step S25. Otherwise, the i-th channel temperature Ti_in still exceeds the limit and the process proceeds to step S25.

[0017] S25 , recording the real-time temperature Ti=Ti_in of the i-th channel and the temperature Ti_last=Ti_in of the previous scanning cycle.

[0018] Furthermore, before entering step S22, if the system needs to be initialized, the process first enters step S25, and then enters step S22 after the system initialization is completed.

[0019] Furthermore, the over-limit state is set as Ti_yx. When the i-th temperature Ti_in is normal, Ti_yx=0 is recorded. When the i-th temperature Ti_in exceeds the limit, Ti_yx=1 is recorded.

[0020] Furthermore, in step S23 , when the i-th channel temperature Ti_in exceeds the limit, it is recorded that Ti_in_yx=Ti_last.

[0021] Furthermore, in step S24 , when the i-th channel temperature Ti_in still exceeds the limit, the limit-exceeding state of the i-th channel temperature Ti_in and the initial temperature Ti_in_yx are kept unchanged.

[0022] Furthermore, in step S5, when the temperature protection logic of the unit is entered, when the temperature of any two circuits of the unit is too high and an alarm is sounded, the emergency shutdown process is started.

[0023] The present invention has the following advantages:

[0024] 1. The temperature over-limit judgment process has been optimized. By setting a temperature over-limit threshold for each channel and periodically scanning each channel temperature, the current temperature in each scanning cycle is compared with the temperature in the previous scanning cycle in real time. If the temperature over-limit threshold is reached, the channel temperature is judged to be in an over-limit state. At the same time, the initial temperature when the channel temperature enters the over-limit state is recorded. Only when the difference between the channel temperature and the initial temperature when it enters the over-limit state is less than the temperature over-limit threshold, the channel temperature is judged to have returned to normal and the over-limit state is cancelled. This makes the temperature over-limit judgment logic more comprehensive and accurate.

[0025] 2. The use of the temperature exceeding the limit status combined with the status of whether the unit outlet circuit breaker is closed is used to determine the next action process of the unit. When the unit outlet circuit breaker is open and the unit temperature is detected to be exceeding the limit, the unit shutdown process is directly started to avoid the risk of tile burning caused by continued temperature increase; when the unit outlet circuit breaker is closed and the unit temperature is detected to be within the limit, it is determined whether the unit temperature is higher than the ultra-high alarm value. If so, the unit temperature protection logic is entered. This can avoid the temperature measuring resistance element being affected by external interference, loose wiring, card failure and other factors, which may cause the temperature signal to change suddenly, causing the unit to stop unexpectedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the existing temperature protection process;

[0027] Figure 2 This is a schematic diagram of the temperature limit-exceeding judgment process of the present invention;

[0028] Figure 3 It is a schematic diagram of the temperature over-limit protection process of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0030] like Figure 3As shown, a method for over-temperature protection of a hydropower station unit is provided. The method combines the temperature over-limit judgment logic with the state judgment of whether the unit outlet circuit breaker is closed and is applied to the temperature protection system of the unit. Thus, it is judged whether the unit system enters the temperature protection logic. The method includes the following steps:

[0031] S1. Set the temperature over-high set value Ti_HH and collect the real-time temperature Ti of the i-th line of the unit.

[0032] S2. Determine whether the temperature of the i-th channel exceeds the limit. If it exceeds the limit, proceed to step S3; if it is normal, proceed to step S4.

[0033] S3. Determine whether the unit outlet circuit breaker is open. If so, start the unit shutdown process. If not, end the determination.

[0034] S4. Determine whether the unit outlet circuit breaker is closed. If so, proceed to step S5; if not, end the determination.

[0035] S5. Determine whether the temperature Ti of the i-th circuit is greater than the over-temperature set value Ti_HH. If so, an over-temperature alarm is triggered for the i-th circuit and the unit temperature protection logic is entered. If not, the determination ends. When the unit temperature protection logic is entered, if the over-temperature alarm is triggered on any two circuits of the unit, the emergency shutdown process is initiated.

[0036] In step S3, when the unit's outlet circuit breaker is in the open state, indicating that the unit is not connected to the grid, the unit may be in an operating state such as a wattage burnout. Combined with the detection of the unit temperature exceeding the limit in step S2, the unit shutdown process should be started directly at this time regardless of whether the temperature reaches the ultra-high alarm value, so as to avoid the risk of wattage burnout caused by continued temperature increase.

[0037] In step S4, when the unit outlet circuit breaker is in the closed state, it means that the unit is in normal grid-connected operation. During the grid-connected operation, if there are problems such as loose wiring, card failure, or external interference, the temperature signal of the temperature measuring thermal resistor element will change suddenly. If the temperature reaches the ultra-high alarm setting, it may cause the unit to stop unexpectedly. Therefore, it is necessary to combine step S2 to detect that the unit temperature has not exceeded the limit, and then enter step S5 to determine whether the unit temperature is higher than the ultra-high alarm setting. If it is higher than the ultra-high alarm setting, the unit temperature protection logic will be entered. This can avoid the occurrence of unit shutdown and ensure the normal and safe production of the unit.

[0038] For the judgment of the over-limit state of the temperature of the i-th channel in step S2, as shown in FIG. Figure 2 As shown, it includes the following steps:

[0039] S21. Set the temperature over-limit value to Ti_set, perform periodic scanning on the i-th temperature, set the i-th temperature of a certain scanning cycle to Ti_in, set the i-th temperature of the previous scanning cycle to Ti_last, and set the initial temperature of the i-th temperature Ti_in before entering the over-limit state to Ti_in_yx.

[0040] S22. Determine whether the temperature Ti_in of the i-th channel exceeds the limit. If normal, proceed to step S23; if exceeded, proceed to step S24.

[0041] S23: Determine whether Ti_in minus Ti_last is greater than Ti_set. If so, the i-th channel temperature Ti_in exceeds the limit and the process proceeds to step S25. Otherwise, the i-th channel temperature Ti_in is normal and the process proceeds to step S25. When it is determined that the i-th channel temperature Ti_in exceeds the limit, record Ti_in_yx = Ti_last.

[0042] S24: Determine whether Ti_in minus Ti_in_yx is less than Ti_set. If so, the i-th channel temperature Ti_in has returned to normal, and the process proceeds to step S25. If not, the i-th channel temperature Ti_in is still out of limit, and the process proceeds to step S25. If it is determined that the i-th channel temperature Ti_in is still out of limit, the i-th channel temperature Ti_in remains out of limit and the initial temperature Ti_in_yx remains unchanged.

[0043] S25 , recording the real-time temperature Ti=Ti_in of the i-th channel and the temperature Ti_last=Ti_in of the previous scanning cycle.

[0044] Before entering step S22, if the system needs to be initialized, it will first enter step S25, and then enter step S22 after the system initialization is completed. After step 25 is completed, the i-th temperature of the next scanning cycle is input into the temperature protection system for over-limit status judgment, and this cycle is repeated.

[0045] In the above judgment step, the over-limit state is set as Ti_yx. When the i-th temperature Ti_in is normal, Ti_yx=0 is recorded. When the i-th temperature Ti_in exceeds the limit, Ti_yx=1 is recorded.

[0046] Through the above-mentioned temperature over-limit judgment steps, the over-limit value of each temperature channel can be set, and then the current temperature of a channel is compared with the temperature of the previous scanning cycle on the channel in real time. If the temperature over-limit value is reached, the temperature of the channel is judged to be in an over-limit state, and the initial temperature of the channel entering the over-limit state is recorded at the same time. After the difference between the temperature of the channel and the initial temperature entering the over-limit state is less than the temperature over-limit value, it is judged that the temperature of the channel has returned to normal and the over-limit state is canceled. In this way, the over-limit state of each temperature channel is judged to ensure the comprehensiveness and accuracy of the temperature over-limit judgment logic.

[0047] The present invention combines the judgment of the temperature exceeding the limit state with the judgment of whether the unit output circuit breaker is closed, thereby jointly judging whether the unit enters the temperature protection logic. While monitoring and protecting the unit temperature in real time, it also avoids misjudgment and missed judgment of temperature, thereby improving the safety and reliability of the unit temperature protection system.

[0048] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for over-limit temperature protection of a hydropower station unit, characterized in that: The following steps are involved: S1. Set the temperature to a high set value Ti_HH and collect the real-time temperature Ti of the i-th circuit of the unit; S2, determine whether the temperature of the i-th channel exceeds the limit. If it exceeds the limit, proceed to step S3; if it is normal, proceed to step S4; S3. Determine whether the unit outlet circuit breaker is open. If so, start the unit shutdown process. If not, end the determination. S4, determine whether the unit outlet circuit breaker is closed, if so, proceed to step S5, if not, end the determination; S5. Determine whether the temperature Ti of the i-th circuit is greater than the over-temperature set value Ti_HH. If so, an over-temperature alarm is triggered and the unit temperature protection logic is activated. Otherwise, the determination is terminated. Determining whether the temperature of the i-th channel exceeds the limit includes the following steps: S21. Set the temperature over-limit value to Ti_set, perform periodic scanning on the i-th channel temperature, set the i-th channel temperature in a certain scanning cycle to Ti_in, set the i-th channel temperature in the previous scanning cycle to Ti_last, and set the initial temperature of the i-th channel temperature before entering the over-limit state to Ti_in_yx; S22, determine whether the temperature Ti_in of the i-th channel exceeds the limit. If it is normal, proceed to step S23; if it is exceeded, proceed to step S24; S23, determine whether Ti_in minus Ti_last is greater than Ti_set, if so, the i-th channel temperature Ti_in exceeds the limit and the process proceeds to step S25, if not, the i-th channel temperature Ti_in is normal and the process proceeds to step S25; S24, determine whether Ti_in minus Ti_in_yx is less than Ti_set. If so, the temperature Ti_in of the i-th channel has returned to normal and the process proceeds to step S25. If not, the temperature Ti_in of the i-th channel still exceeds the limit and the process proceeds to step S25; S25 , recording the real-time temperature Ti=Ti_in of the i-th channel and the temperature Ti_last=Ti_in of the previous scanning cycle.

2. A method for over-temperature protection of a hydropower station unit according to claim 1, characterized in that: Before entering step S22, if the system needs to be initialized, first enter step S25, and then enter step S22 after the system initialization is completed.

3. A method for over-temperature protection of a hydropower station unit according to claim 1, characterized in that: Set the over-limit state to Ti_yx. When the temperature Ti_in of the i-th channel is normal, record Ti_yx=0. When the temperature Ti_in of the i-th channel exceeds the limit, record Ti_yx=1.

4. The method for over-temperature protection of a hydropower station unit according to claim 1, characterized in that: In step S23 , when the i-th channel temperature Ti_in exceeds the limit, record Ti_in_yx=Ti_last.

5. The method for over-temperature protection of a hydropower station unit according to claim 1, characterized in that: In step S24 , when the i-th channel temperature Ti_in still exceeds the limit, the limit-exceeding state of the i-th channel temperature Ti_in and the initial temperature Ti_in_yx are kept unchanged.

6. The method for over-temperature protection of a hydropower station unit according to claim 1, characterized in that: In step S5, when the unit temperature protection logic is entered, if any two circuits of the unit have excessive temperature alarms, the emergency shutdown process is started.

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