Overspeed protection control system of steam turbine

Abstract

The utility model relates to the technical field of steam turbine safety monitoring, and discloses an overspeed protection control system of a steam turbine, which is characterized in that one path of input of a detection module is connected to a target rotating speed probe through a first conversion module and is used for acquiring first rotating speed information of a target steam turbine; the other path of input is connected to a target safety monitoring probe through a second conversion module and used for collecting safety monitoring information of a target steam turbine, and the safety monitoring information comprises shaft vibration information, axial displacement information, eccentric information, differential expansion information and cylinder expansion information; one output of the detection module is connected with the adjustment unit through the selection unit, and the other output is connected with the adjustment unit through the difference unit, the comparison unit and the selection unit in sequence; the output end of the adjusting unit is connected with target equipment through the protection control module. According to the utility model, by quantifying the influence of safety monitoring information in the turbine TSI system on the rotating speed, the detection precision of the rotating speed of the turbine is improved, and more accurate overspeed protection on the turbine is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine safety monitoring, and specifically, to an overspeed protection control system for a steam turbine. Background Art

[0002] The overspeed protection control of a steam turbine is an important mechanism to ensure the safe operation of the steam turbine. It is one of the items in the turbine safety monitoring system TSI. Usually, multiple overspeed protection thresholds are set to ensure the safe operation of the steam turbine. For example, when the steam turbine speed reaches 103% of the rated speed, the OPC overspeed protection will be triggered, and the OPC solenoid valve will be controlled to quickly close the GV (high-pressure regulating valve) and IV (intermediate-pressure regulating valve) to prevent the steam turbine speed from rising further. When the steam turbine speed reaches 110% of the rated speed, the DEH overspeed protection will be triggered, and the control of the steam turbine speed will be achieved through the action of the AST (Automatic Trip System) solenoid valve. When the steam turbine speed exceeds 111% - 112% of the rated speed, the mechanical overspeed protection will be triggered to ensure that when the OPC overspeed protection and DEH overspeed protection fail, the steam supply to the steam turbine can still be quickly cut off to prevent the unit from being damaged by overspeed.

[0003] Therefore, since the settings of each threshold are relatively close, it is necessary to accurately collect the speed of the steam turbine to avoid a series of impacts caused by the steam turbine shutdown due to false speed reporting. However, in the related art, the impacts of other monitoring items in the turbine safety monitoring system TSI, such as shaft vibration, relative expansion, axial displacement, etc., on the speed monitoring are usually not considered. Summary of the Utility Model

[0004] The purpose of the utility model is to provide an overspeed protection control system for a steam turbine, which realizes that when monitoring the steam turbine speed, the impacts of other monitoring items in the turbine safety monitoring system TSI on the speed are fully considered. When other monitoring items are normal, the real-time speed of the steam turbine collected is normally used for overspeed protection of the steam turbine. When other monitoring items are higher than or equal to the threshold, according to the difference between the other monitoring items higher than the threshold, the real-time speed of the steam turbine is corrected, and the corrected speed is used for the overspeed protection function of the steam turbine. It has the effect of being able to perform more accurate overspeed protection on the steam turbine and preventing overspeed misjudgment, so as to solve the technical problem that in the overspeed protection of the steam turbine, when monitoring the steam turbine speed, the impacts of other monitoring items in the turbine safety monitoring system TSI on the speed monitoring are not considered.

[0005] The utility model is realized through the following technical solutions:

[0006] An overspeed protection control system for a steam turbine, cooperating with a target speed probe and a target safety monitoring probe in the TSI system of the target steam turbine, includes:

[0007] A first conversion module, a second conversion module, a detection module, a speed adjustment module, a protection control module and a speed simulation module. The speed adjustment module includes a selection unit and an adjustment unit, and the speed simulation module includes a difference unit and a comparison unit;

[0008] One input of the detection module is connected to the target speed probe through the first conversion module for collecting the first speed information of the target steam turbine, and the other input is connected to the target safety monitoring probe through the second conversion module for collecting the safety monitoring information of the target steam turbine. The safety monitoring information includes shaft vibration information, axial displacement information, eccentricity information, differential expansion information and cylinder expansion information. One output of the detection module is connected to the adjustment unit through the selection unit, and the other output is connected to the adjustment unit through the difference unit, the comparison unit and the selection unit in sequence. The output end of the adjustment unit is connected to the target device through the protection control module;

[0009] Through the above technical solution, the detection module simultaneously receives the real-time speed information and the real-time safety monitoring information of the target steam turbine and keeps detecting the real-time safety monitoring. One output of the detection module continuously transmits the real-time speed information, that is, the first speed information, to the adjustment unit through the selection unit, and the adjustment unit keeps monitoring the real-time speed information of the target steam turbine. The shaft vibration information is also called relative vibration information, which characterizes the radial vibration amplitude of the steam turbine rotor. The axial displacement information is also called axial shift information, which characterizes the axial shift amount of the steam turbine rotor. The eccentricity information is also called the radial position of the shaft, which refers to the radial average position of the rotor in the bearing and is mainly used to monitor the bending degree of the large shaft. The differential expansion information is also called relative thermal expansion, which is the difference between the expansion amount of the steam turbine rotor and the expansion amount of the cylinder monitored. The cylinder expansion information is the absolute expansion amount of the cylinder measured. These information will all have a certain impact on the speed monitoring of the steam turbine. For example, it will cause changes in the position, magnetic field, distance, etc. between the probe and the measurement point, and then affect the measurement of the speed. Considering these impacts, a more accurate steam turbine speed can be obtained;

[0010] When the detection module detects that there is target monitoring information in the safety monitoring information that is greater than or equal to the preset safety monitoring threshold, the difference unit receives the target monitoring information and obtains the target difference; the comparison unit corrects the first speed information according to the received target difference, obtains the second speed information and transmits the second speed information to the selection unit;

[0011] Through the above technical solution, when the real-time safety monitoring information is higher than or equal to the safety monitoring threshold, the detection module transmits the real-time rotational speed information and the real-time safety monitoring information, that is, the first rotational speed information and the target monitoring information, to the difference unit. Subsequently, the difference unit calculates the difference between the real-time safety monitoring information and the safety monitoring threshold, that is, the target difference, and then transmits it to the comparison unit. The comparison unit, according to the pre-set settings, compares the target difference and the first rotational speed information with the pre-set difference and rotational speed information to obtain a corrected rotational speed, that is, the second rotational speed information, and transmits it to the selection unit, realizing the quantification of the influence of the real-time safety monitoring information on the real-time rotational speed and obtaining a more accurate steam turbine rotational speed;

[0012] When the selection unit only receives the first rotational speed information, it transmits the first rotational speed information to the adjustment unit. When the selection unit receives both the first rotational speed information and the second rotational speed information at the same time, it transmits the second rotational speed information to the adjustment unit;

[0013] Through the above technical solution, the selection of the rotational speed information is completed. When only the first rotational speed information is received, that is, the remaining safety monitoring information remains within the normal range. At this time, it is considered that the influence of the remaining safety monitoring information on the steam turbine rotational speed can be ignored, and the real-time rotational speed information collected by the rotational speed probe is accurate. When both the first rotational speed information and the second rotational speed information are received at the same time, since the second rotational speed information is a more accurate rotational speed considering the influence of the real-time safety monitoring information, the selection unit will select the second rotational speed information and transmit it to the adjustment unit to achieve a more accurate steam turbine overspeed protection;

[0014] The adjustment unit generates an adjustment command according to the first rotational speed information or the second rotational speed information, and then controls the target device through the protection control module to achieve overspeed protection for the target steam turbine;

[0015] Through the above technical solution, the adjustment unit will actually only receive one rotational speed information at the same time and generate adjustment commands such as maintaining the current state of the target steam turbine, needing to reduce speed, and needing to stop according to this rotational speed information. The protection control module further accurately controls target devices such as each regulating valve, warning device, and stopping device according to the adjustment command to complete the overspeed protection for the target steam turbine.

[0016] To better implement the present invention, further, the rotational speed simulation module further includes a difference processing unit. The input end of the difference processing unit is connected to the difference unit, and the output end of the difference processing unit is connected to the comparison unit;

[0017] The difference processing unit is used to select and transmit the target difference corresponding to the target monitoring information with the largest percentage of the transmitted target difference to the comparison unit when the number of the target monitoring information is greater than or equal to two items.

[0018] Through the above technical solution, it is possible to select the target monitoring information that has the greatest impact on the steam turbine speed, so as to quantify the corresponding impact in the subsequent process and accurately correct the steam turbine speed.

[0019] To better implement the present utility model, further, the difference processing unit is further configured to, when the number of items of the target monitoring information is greater than or equal to two, assign corresponding weights to the target differences corresponding to each item of the target monitoring information according to a preset first weight table, generate a comprehensive difference and transmit it to the comparison unit.

[0020] Through the above technical solution, it is possible to comprehensively consider the impact of all target monitoring information on the steam turbine speed, so as to quantify the corresponding impact in the subsequent process and more accurately correct the steam turbine speed.

[0021] To better implement the present utility model, further, the first conversion module further includes a probe detection unit, and the probe detection unit is used to obtain the type information of the target speed probe, and the type information includes a Hall speed probe, a magnetoresistive speed probe or an eddy current speed probe;

[0022] The difference processing unit is further configured to, when the number of items of the target monitoring information is greater than or equal to two, assign corresponding weights to the target differences corresponding to each item of the target monitoring information according to a preset second weight table, the first weight table and the type information, generate a comprehensive difference and transmit it to the comparison unit.

[0023] Through the above technical solution, the impact of the target monitoring information on different target speed probes is further considered, so as to quantify the corresponding impact in the subsequent process and more accurately correct the steam turbine speed.

[0024] To better implement the present utility model, further, the second weight table is configured such that when the type information is a Hall speed probe, the weight values corresponding to the target differences corresponding to each item of the target monitoring information are, from high to low, the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the eccentricity information weight and the differential expansion information weight.

[0025] Through the above technical solution, since the Hall speed probe works based on the Hall effect, directly senses the magnetic field and converts it into an electrical signal, and the Hall probe usually has a certain adaptability to temperature, therefore, the impact on the relative thermal expansion information, that is, the differential expansion information, is the smallest. After experiments and simulations, the influence degree of other safety monitoring information on the speed detection result of the Hall speed probe is obtained. After assigning corresponding weights, the accuracy of the overspeed protection control of the steam turbine can be further improved.

[0026] To better implement the present utility model, further, the second weight table is configured such that when the type information is a magnetoresistive speed probe, the weight values corresponding to the target differences of the respective target monitoring information are, from high to low, the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the differential expansion information weight, and the eccentricity information weight.

[0027] Through the above technical solution, after experiments and simulations, the influence degree of other safety monitoring information on the speed detection result of the magnetoresistive speed probe is obtained. After assigning corresponding weights, the accuracy of the overspeed protection control for the steam turbine can be further improved.

[0028] To better implement the present utility model, further, the second weight table is configured such that when the type information is an eddy current speed probe, the weight values corresponding to the target differences of the respective target monitoring information are, from high to low, the axial displacement information weight, the shaft vibration information weight, the cylinder expansion information weight, the eccentricity information weight, and the differential expansion information weight.

[0029] Through the above technical solution, since the eddy current speed probe works based on the eddy current effect and indirectly measures the speed by measuring the eddy current generated on the surface of the measured object, and the eddy current speed probe also has a certain adaptability to temperature, the influence on the relative thermal expansion information, that is, the differential expansion information, is the smallest. After experiments and simulations, the influence degree of other safety monitoring information on the speed detection result of the eddy current speed probe is obtained. After assigning corresponding weights, the accuracy of the overspeed protection control for the steam turbine can be further improved.

[0030] Compared with the prior art, the present utility model has the following advantages and beneficial effects:

[0031] Through a system structure different from the prior art, the present system incorporates multiple safety monitoring information that can affect the steam turbine speed into the consideration scope of the steam turbine overspeed protection. When the safety monitoring information is normal, the steam turbine speed is monitored normally. When the safety monitoring information is too large, the influence is quantified and the quantified result is used to correct the real-time speed. The corrected steam turbine speed is used for the steam turbine overspeed protection, which improves the detection accuracy of the steam turbine speed, and then enables more accurate overspeed protection for the steam turbine. It can not only avoid malignant accidents such as rotor fracture and runaway that may occur when the steam turbine speed is too high, but also avoid excessive steam turbine shutdowns, further improving the working efficiency of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present utility model will be further described below in conjunction with the following drawings and embodiments. All the innovative concepts of the present utility model should be regarded as the disclosed content and the protection scope of the present utility model.

[0033] Figure 1Schematic diagram of Embodiment 1 of the overspeed protection control system for a steam turbine in this application.

[0034] Figure 2 Schematic diagram of Embodiment 2 of the overspeed protection control system for a steam turbine in this application.

[0035] Figure 3 Schematic diagram of Embodiment 3 of the overspeed protection control system for a steam turbine in this application.

[0036] Wherein: 1. Overspeed protection control system of the steam turbine; 101. First conversion module; 102. Second conversion module; 103. Detection module; 104. Speed adjustment module; 105. Protection control module; 106. Speed simulation module; 107. Selection unit; 108. Adjustment unit; 109. Difference unit; 110. Comparison unit; 111. Difference processing unit; 112. Probe detection unit; 2. Target speed probe; 3. Target safety monitoring probe; 4. Target device. Detailed implementation mode

[0037] Embodiment 1:

[0038] An overspeed protection control system 1 of a steam turbine in this embodiment is coordinated with a target speed probe 2 and a target safety monitoring probe 3 in the TSI system of the target steam turbine. As Figure 1 shown, it includes:

[0039] A first conversion module 101, a second conversion module 102, a detection module 103, a speed adjustment module 104, a protection control module 105 and a speed simulation module 106. The speed adjustment module 104 includes a selection unit 107 and an adjustment unit 108. The speed simulation module 106 includes a difference unit 109 and a comparison unit 110;

[0040] One input of the detection module 103 is connected to the target speed probe 2 through the first conversion module 101 for collecting the first speed information of the target steam turbine. The other input is connected to the target safety monitoring probe 3 through the second conversion module 102 for collecting the safety monitoring information of the target steam turbine. The safety monitoring information includes shaft vibration information, axial displacement information, eccentricity information, differential expansion information and cylinder expansion information. One output of the detection module 103 is connected to the adjustment unit 108 through the selection unit 107. The other output is connected to the adjustment unit 108 through the difference unit 109, the comparison unit 110 and the selection unit 107 in sequence. The output end of the adjustment unit 108 is connected to the target device through the protection control module 105;

[0041] In this embodiment, there are no restrictions on the number, type, signal voting logic, etc. of the target speed probes 2 that the first conversion module 101 can be connected to. For example, conventional three speed probes and a "two-out-of-three" voting logic can be adopted. The first conversion module 101 can also select converters corresponding to the number of probes according to the number of probes, and then connect them to the same backplane for voting. Similarly, there are no restrictions on the connection of the second conversion module 102 to the target safety monitoring probes 3 either.

[0042] When the detection module 103 detects that there is target monitoring information in the safety monitoring information that is greater than or equal to the preset safety monitoring threshold, the difference unit 109 receives the target monitoring information and obtains the target difference; the comparison unit 110 corrects the first speed information according to the received target difference, obtains the second speed information and transmits the second speed information to the selection unit 107;

[0043] In this embodiment, since this application focuses on the impact of each safety monitoring information on speed acquisition and overspeed protection, if there are major abnormalities in the remaining safety monitoring information, it may directly cause the steam turbine to shut down. Therefore, the safety monitoring threshold is set to be less than the warning threshold of each safety monitoring information in the TSI system;

[0044] After receiving the target difference, the comparison unit 110 compares the target difference and the first speed information with the preset difference and speed information, and a corrected speed can be obtained. For example, if the current target difference is 5.6% and the first speed is 2700 r / min, then select the preset difference range of 5.5% - 6% corresponding to 5.6%, and obtain the speed corresponding to the preset difference range of 5.5% - 6% as 2800 r / min, and use the speed of 2800 r / min as the second speed information.

[0045] When the selection unit 107 only receives the first speed information, it transmits the first speed information to the adjustment unit 108. When the selection unit 107 receives both the first speed information and the second speed information at the same time, it transmits the second speed information to the adjustment unit 108;

[0046] In this embodiment, the method adopted is to add a selection unit 107 in the speed adjustment module 104 to select the first speed information and the second speed information. Of course, the selection unit 107 can also be set in the detection module 103. After the detection module 103 selects the first speed information and the second speed information, it then transmits the corresponding speed information to the speed adjustment module 104.

[0047] The adjustment unit 108 generates an adjustment command according to the first speed information or the second speed information, and then controls the target device through the protection control module 105 to achieve overspeed protection of the target steam turbine;

[0048] In this embodiment, the adjustment commands include maintaining the current state, requiring speed reduction, requiring speed increase, and requiring shutdown. At the same time, speed increase and speed reduction will also include specific amounts of increase and decrease.

[0049] Of course, the overspeed protection control system 1 of the steam turbine in this embodiment can also be connected to the upper computer of the TSI system of the target steam turbine, so as to facilitate technicians to obtain and monitor relevant data, and, according to the actual situation of the target steam turbine, manually adjust the safety monitoring threshold, adjustment commands, relevant parameters of the comparison unit 110, etc.

[0050] The working principle of this embodiment is as follows:

[0051] The overspeed protection control system 1 of the steam turbine accesses the TSI system of the target steam turbine through the first conversion module 101, the second conversion module 102, and the protection control module 105, and obtains the first speed information and safety monitoring information of the target steam turbine through the first conversion module 101 and the second conversion module 102; the detection module 103 continuously transmits the first speed information to the subsequent modules to maintain the monitoring of the speed and normal overspeed protection, and maintain the monitoring of the safety monitoring information. When the detection module 103 detects that the safety monitoring information is too large, it transmits the target monitoring information and the first speed information to the speed simulation module 106 to complete the correction of the first speed information and obtain the second speed information; the selection unit 107 selects to transmit only the second speed information to the adjustment unit 108 to realize the correction of the influence of the safety monitoring information on the steam turbine speed and complete more accurate overspeed protection.

[0052] Embodiment 2:

[0053] This embodiment is further optimized on the basis of Embodiment 1. As Figure 2 shown, in this embodiment, the speed simulation module 106 further includes a difference processing unit 111. The input end of the difference processing unit 111 is connected to the difference unit 109, and the output end of the difference processing unit 111 is connected to the comparison unit 110;

[0054] The difference processing unit 111 is used to select and transmit the target difference corresponding to the item of target monitoring information with the largest percentage of the target difference to the comparison unit 110 when the number of items of the target monitoring information is greater than or equal to two;

[0055] At the same time, in this embodiment, the difference processing unit 111 is further configured to assign corresponding weights to the target differences corresponding to each item of target monitoring information according to a preset first weight table to generate a comprehensive difference and transmit it to the comparison unit 110 when the number of items of the target monitoring information is greater than or equal to two;

[0056] In this embodiment, the above two implementation manners can be switched according to the actual situation to meet the actual detection requirements. Moreover, the first weight table is also applied to the previous implementation manner. When the number of items of the target monitoring information is greater than or equal to two, according to the preset first weight table, weights are assigned to the target differences corresponding to each item of the target monitoring information, and then the target difference corresponding to the item of the target monitoring information with the largest percentage of the transmitted target difference is selected and transmitted to the comparison unit 110; the first weight table is a weight table representing the situation of the steam turbine itself, which can be set according to the actual situation of the target steam turbine, and the corresponding weight values can be flexibly adjusted according to the usage situation of the target steam turbine;

[0057] For example, for the previous implementation manner, only one target difference is output. The target monitoring information received by the difference processing unit 111 is shaft vibration information and cylinder expansion information, and the percentages of their respective target differences are 8% and 10% respectively, and the corresponding weight values are 1.05 and 0.9 respectively. Then the percentages of the processed target differences are 8.4% and 9% respectively. The percentage of the target difference of the cylinder expansion information selected for output is 9% and transmitted to the comparison unit 110;

[0058] For the latter implementation manner, a comprehensive target difference is output. The target monitoring information received by the difference processing unit 111 is shaft vibration information and cylinder expansion information, and the percentages of their respective target differences are 8% and 10% respectively, and the corresponding weight values are 1.05 and 0.9 respectively. Then the comprehensive weight value is 8% * 1.05 / (1.05 + 0.9) ≈ 4.31 + 10% * 0.9 / (1.05 + 0.9) ≈ 8.92%. The comprehensive weight value of 8.92% is output and transmitted to the comparison unit 110.

[0059] Therefore, by adopting this implementation manner, the influence of the target monitoring information can be corrected. Subsequently, whether only one target monitoring information is selected to correct the rotational speed or all target monitoring information is comprehensively considered to correct the rotational speed, it is more accurate.

[0060] The working principle of this embodiment is as follows:

[0061] The overspeed protection control system 1 of the steam turbine accesses the TSI system of the target steam turbine through the first conversion module 101, the second conversion module 102 and the protection control module 105, and obtains the first rotational speed information and safety monitoring information of the target steam turbine through the first conversion module 101 and the second conversion module 102; the detection module 103 continuously transmits the first rotational speed information to the subsequent modules to maintain the monitoring of the rotational speed and normal overspeed protection, and maintain the monitoring of the safety monitoring information. When the detection module 103 detects that the safety monitoring information is too large, it transmits the type information, the target monitoring information and the first rotational speed information to the rotational speed simulation module 106. In the rotational speed simulation module 106, the difference processing unit 111 will perform a first correction on the target difference, and then complete the correction of the first rotational speed information to obtain the second rotational speed information; the selection unit 107 selects to transmit only the second rotational speed information to the adjustment unit 108, so as to correct the influence of the safety monitoring information on the rotational speed of the steam turbine and complete more accurate overspeed protection

[0062] Embodiment 3:

[0063] On the basis of Embodiment 2, this embodiment is further optimized. As Figure 3 shown, the first conversion module 101 further includes a probe detection unit 112, and the probe detection unit 112 is used to obtain the type information of the target rotational speed probe 2, and the type information includes a Hall rotational speed probe, a magnetoresistive rotational speed probe or an eddy current rotational speed probe;

[0064] The difference processing unit 111 is further configured to, when the number of the target monitoring information is greater than or equal to two, assign corresponding weights to the target differences corresponding to each item of the target monitoring information according to the preset second weight table, the first weight table and the type information, generate a comprehensive difference and transmit it to the comparison unit 110;

[0065] Specifically, in this embodiment, the second weight table is configured such that when the type information is a Hall rotational speed probe, the weight values corresponding to the target differences corresponding to each item of the target monitoring information from high to low are the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the eccentricity information weight and the differential expansion information weight;

[0066] When the type information is a magnetoresistive rotational speed probe, the weight values corresponding to the target differences corresponding to each item of the target monitoring information from high to low are the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the differential expansion information weight and the eccentricity information weight;

[0067] When the type information is an eddy current rotational speed probe, the weight values corresponding to the target differences corresponding to each item of the target monitoring information from high to low are the axial displacement information weight, the shaft vibration information weight, the cylinder expansion information weight, the eccentricity information weight and the differential expansion information weight;

[0068] By adopting the above embodiments, it is also possible to further correct the influence on the target monitoring information according to the type of the target speed probe 2. In this embodiment, the second weight table is a weight table representing the influence of the target monitoring information on the probe. Therefore, two weight adjustments will be performed using the first weight table and the second weight table. For example, only one target difference is output. The target monitoring information received by the difference processing unit 111 is shaft vibration information and cylinder expansion information, and the percentages of their respective target differences are 8% and 10% respectively. In the first weight table, the corresponding weight values are 1.05 and 0.9 respectively, and the probe is a Hall speed probe. In the second weight table, the corresponding weight values are 1.03 and 0.95 respectively. Then, the percentages of the processed target differences are 1.05 * 1.03 * 8% ≈ 8.65% and 0.9 * 0.95 * 9% ≈ 7.7% respectively. The percentage of the target difference of the shaft vibration information selected for output is 8.65% to the comparison unit 110.

[0069] Other parts of this embodiment are the same as those of Embodiment 2, so they will not be described in detail.

[0070] The working principle of this embodiment is as follows:

[0071] The overspeed protection control system 1 of the steam turbine accesses the TSI system of the target steam turbine through the first conversion module 101, the second conversion module 102, and the protection control module 105. Through the first conversion module 101 and the second conversion module 102, the first speed information and safety monitoring information of the target steam turbine are obtained, and, through the probe detection unit 112 in the first conversion module 101, the type information of the target speed probe 2 is obtained; the detection module 103 continuously transmits the first speed information to the subsequent modules to maintain the monitoring of the speed and normal overspeed protection, and to maintain the monitoring of the safety monitoring information. When the detection module 103 detects that the safety monitoring information is too large, it transmits the type information, the target monitoring information, and the first speed information to the speed simulation module 106. In the speed simulation module 106, the difference processing unit 111 will correct the target difference twice, and then complete the correction of the first speed information to obtain the second speed information; the selection unit 107 selects to transmit only the second speed information to the adjustment unit 108 to achieve the correction of the influence of the safety monitoring information on the steam turbine speed and complete more accurate overspeed protection.

[0072] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Any simple modification and equivalent change made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. An overspeed protection control system (1) of a steam turbine, cooperating with a target speed probe (2) and a target safety monitoring probe (3) in the TSI system of a target steam turbine, is characterized in that, Including: A first conversion module (101), a second conversion module (102), a detection module (103), a rotational speed adjustment module (104), a protection control module (105), and a rotational speed simulation module (106). The rotational speed adjustment module (104) includes a selection unit (107) and an adjustment unit (108). The rotational speed simulation module (106) includes a difference unit (109) and a comparison unit (110); One input of the detection module (103) is connected to the target rotational speed probe (2) through the first conversion module (101) for collecting the first rotational speed information of the target steam turbine. The other input is connected to the target safety monitoring probe (3) through the second conversion module (102) for collecting the safety monitoring information of the target steam turbine. The safety monitoring information includes shaft vibration information, axial displacement information, eccentricity information, differential expansion information, and cylinder expansion information. One output of the detection module (103) is connected to the adjustment unit (108) through the selection unit (107). The other output is sequentially connected to the adjustment unit (108) through the difference unit (109), the comparison unit (110), and the selection unit (107). The output end of the adjustment unit (108) is connected to the target device through the protection control module (105); When the detection module (103) detects that there is target monitoring information in the safety monitoring information that is greater than or equal to the preset safety monitoring threshold, the difference unit (109) receives the target monitoring information and obtains the target difference; The comparison unit (110) corrects the first rotational speed information according to the received target difference, obtains the second rotational speed information, and transmits the second rotational speed information to the selection unit (107); When the selection unit (107) only receives the first rotational speed information, it transmits the first rotational speed information to the adjustment unit (108). When the selection unit (107) receives both the first rotational speed information and the second rotational speed information at the same time, it transmits the second rotational speed information to the adjustment unit (108); The adjustment unit (108) generates an adjustment command according to the first rotational speed information or the second rotational speed information, and then controls the target device through the protection control module (105) to achieve overspeed protection for the target steam turbine.

2. The overspeed protection control system (1) of a steam turbine according to claim 1, characterized in that: The rotational speed simulation module (106) further includes a difference processing unit (111). The input end of the difference processing unit (111) is connected to the difference unit (109), and the output end of the difference processing unit (111) is connected to the comparison unit (110); The difference processing unit (111) is used to select and transmit the target difference corresponding to the item of target monitoring information with the largest percentage of the transmitted target difference to the comparison unit (110) when the number of the target monitoring information is greater than or equal to two.

3. The overspeed protection control system (1) of a steam turbine according to claim 2, characterized in that: The difference processing unit (111) is further configured to, when the number of pieces of the target monitoring information is greater than or equal to two, assign corresponding weights to the target differences corresponding to the pieces of the target monitoring information according to a preset first weight table, generate a comprehensive difference and transmit it to the comparison unit (110).

4. The overspeed protection control system (1) of a steam turbine according to claim 3, wherein: The first conversion module (101) further includes a probe detection unit (112), and the probe detection unit (112) is configured to obtain the type information of the target speed probe (2), and the type information includes a Hall speed probe, a magnetoresistive speed probe or an eddy current speed probe; The difference processing unit (111) is further configured to, when the number of pieces of the target monitoring information is greater than or equal to two, assign corresponding weights to the target differences corresponding to the pieces of the target monitoring information according to a preset second weight table, the first weight table and the type information, generate a comprehensive difference and transmit it to the comparison unit (110).

5. The overspeed protection control system (1) of a steam turbine according to claim 4, wherein: The second weight table is configured such that when the type information is a Hall speed probe, the weight values corresponding to the target differences corresponding to the pieces of the target monitoring information from high to low are respectively the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the eccentricity information weight and the differential expansion information weight.

6. The overspeed protection control system (1) of a steam turbine according to claim 4, wherein: The second weight table is configured such that when the type information is a magnetoresistive speed probe, the weight values corresponding to the target differences corresponding to the pieces of the target monitoring information from high to low are respectively the shaft vibration information weight, the cylinder expansion information weight, the axial displacement information weight, the differential expansion information weight and the eccentricity information weight.

7. The overspeed protection control system (1) of a steam turbine according to claim 4, wherein: The second weight table is configured such that when the type information is an eddy current speed probe, the weight values corresponding to the target differences corresponding to the pieces of the target monitoring information from high to low are respectively the axial displacement information weight, the shaft vibration information weight, the cylinder expansion information weight, the eccentricity information weight and the differential expansion information weight.

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