Method and system for improving reliability of thermal two-out-of-three protection logic of thermal power plant

Abstract

The invention discloses a method and system for improving reliability of thermal two-out-of-three protection logic of a thermal power plant, and relates to the technical field of thermal protection logic setup, and the method comprises the steps: carrying out the overrun and non-bad quality judgment of a signal of a measurement point, and generating a first signal, a second signal and a third signal; carrying out bad quality judgment on the signal of the measuring point to generate a fourth signal, a fifth signal and a sixth signal; inputting the fourth signal, the fifth signal and the sixth signal into a two-out-of-three module to generate a seventh signal; inputting the first signal, the second signal, the third signal and the seventh signal into a two-out-of-four module to generate an eighth signal; carrying out AND on the fourth signal, the fifth signal and the sixth signal to generate a ninth signal for detecting complete failure of the detection point; and performing OR operation on the eighth signal and the ninth signal to generate a tenth signal. According to the method for improving the reliability of the thermal two-out-of-three protection logic of the thermal power plant, provided by the invention, the traditional two-out-of-three judgment is changed into two-out-of-four and logic judgment is added, so that the fault condition of a measuring point can be more flexibly dealt with.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal protection logic construction, and in particular to a method and system for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant. Background Art

[0002] The so-called "thermal protection" refers to the automatic operation of related systems or equipment according to the nature and degree of the abnormal situation or accident in the thermal production process, in accordance with the predetermined processing procedures, in order to eliminate the abnormality and prevent the expansion of the accident, and ensure the safety of personnel and equipment. According to the different objects of protection, thermal protection can be roughly divided into: unit protection, boiler protection, steam turbine protection, electrical protection, auxiliary machine protection and auxiliary system protection.

[0003] According to industry standards, no matter the object of protection is a unit, boiler, steam turbine or auxiliary equipment, its protection should adopt three-out-of-three logic judgment method (if there are four measuring points, use four-out-of-two), such as low feed water flow protection and drum water level protection in the boiler main protection; low lubricating oil tank level protection and EH oil pressure low protection in the steam turbine main protection; water cut-off protection in electrical protection, etc. Most power plants use the analog signal from three local measuring points to compare with the fixed value and then make a three-out-of-two judgment.

[0004] However, due to irregular installation of measuring points, unreasonable sampling methods, quality problems of transmitters, or maintenance problems, protection malfunctions or refusal to operate due to measuring point failures often occur. In addition to ensuring that measuring points are installed in accordance with regulations, sampling methods are reasonable, transmitter quality is improved, and maintenance is strengthened, it is also necessary to strengthen logical reliability when building configuration logic. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is to reduce the probability of protection misoperation or refusal to operate due to measurement point failure.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, comprising:

[0008] Performing quality judgment on the signals at the three measuring points as being over the limit and not bad, and generating a first signal, a second signal and a third signal;

[0009] Performing a bad quality judgment on the signals at the three measuring points to generate a fourth signal, a fifth signal and a sixth signal;

[0010] Inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module to generate a seventh signal;

[0011] Inputting the first signal, the second signal, the third signal and the seventh signal into a four-to-two module to generate an eighth signal;

[0012] The fourth signal, the fifth signal and the sixth signal are ANDed together to generate a ninth signal indicating that the detection point has completely failed;

[0013] The eighth signal and the ninth signal are ORed together to generate a tenth signal.

[0014] As a preferred solution of the method for improving the reliability of thermal power plant three-out-of-two protection logic according to the present invention, the above-mentioned over-limit and non-bad quality judgment includes:

[0015] The analog signals of the three measuring points are judged for high and low limits. When the preset threshold is exceeded, the switch value 1 is output, and when the preset threshold is not exceeded, the switch value 0 is output.

[0016] The analog signal is transmitted to the quality judgment module. If the signal is of bad quality, the switch value 1 is output, and if the signal is of good quality, the switch value 0 is output;

[0017] Perform a negation operation on the output of the quality judgment module, converting 1 to 0 and 0 to 1;

[0018] The limit judgment result is ANDed with the quality judgment result after negation. When the signal exceeds the limit and is of good quality, the switch value 1 is output, and the switch value 0 is output in other cases.

[0019] Three switch signals are obtained, namely a first signal, a second signal and a third signal.

[0020] As a preferred solution of the method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant described in the present invention, the bad quality judgment includes: making a quality judgment on the analog quantities of the three measuring points, if the signal is of bad quality, outputting a switch quantity 1, if the signal is of good quality, outputting a switch quantity 0, and obtaining three switch quantity signals, which are the fourth signal, the fifth signal and the sixth signal respectively.

[0021] Generating the seventh signal includes inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module, and when at least two of the three input signals are 1, the fourth signal is output as 1, otherwise the output is 0.

[0022] As a preferred solution of the method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant described in the present invention, the generating of the eighth signal includes inputting the first signal, the second signal, the third signal and the seventh signal into a four-out-of-two module, and when at least two of the four input signals are 1, the fifth signal is output as 1, otherwise the output is 0.

[0023] As a preferred solution of the method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant described in the present invention, wherein: the generation of a ninth signal for detecting a complete failure of a measuring point includes inputting the fourth signal, the fifth signal and the sixth signal into an AND module, and when the three input signals are all 1, the ninth signal output is 1, otherwise the output is 0.

[0024] As a preferred solution of the method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant described in the present invention, the generating of the tenth signal includes inputting the eighth signal and the ninth signal into an OR operation module, and when either the eighth signal or the ninth signal is 1, the tenth signal is output as 1, otherwise the output is 0.

[0025] Another object of the present invention is to provide a system for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant. The system can solve the problem of false operation and refusal to operate caused by measurement point failures in the existing thermal protection system of a thermal power plant by constructing a multi-signal redundant judgment system based on bad quality signals, thereby effectively improving the system reliability and adaptability.

[0026] To solve the above technical problems, the present invention provides the following technical solutions: A system for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, comprising: a data input layer, a logic control layer and an output execution layer; the data input layer collects and pre-processes the signal data of the measuring point, and transmits the processing results to the logic control layer; the logic control layer performs logical operation processing on the signal of the data input layer, generates the signal required by the protection logic, and determines whether the conditions for triggering protection are met; the output execution layer triggers protection or alarm control according to the output signal of the logic control layer.

[0027] A computer program product includes a computer program. When the computer program is executed by a processor, the steps of the method for improving the reliability of the thermal two-out-of-three protection logic of a thermal power plant are implemented as described above.

[0028] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the method for improving the reliability of thermal three-out-of-two protection logic of a thermal power plant are implemented as described above.

[0029] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for improving the reliability of thermal two-out-of-three protection logic in a thermal power plant as described above.

[0030] Beneficial effects of the present invention: The method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant provided by the present invention introduces redundant judgment of bad quality signals, changes the traditional "three-out-of-two" judgment to "four-out-of-two" and adds additional logical judgment, which can more flexibly deal with measurement point failure situations. In the case of failure of two measurement points, the logic can still judge normally and trigger the protection instead of refusing to move. At the same time, when all measurement points fail, the system can also shut down or alarm in time to avoid potential hazards. The method can choose whether to shut down directly or only trigger an alarm when all measurement points fail according to actual conditions, so as to adapt to the operating requirements of different power plants. The optimization logic is based on the improvement of the existing DCS system module, does not require additional hardware, and is easy to integrate and implement in the existing thermal power plant system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 An overall flow chart of a method for improving the reliability of thermal two-out-of-three protection logic in a thermal power plant provided by an embodiment of the present invention.

[0033] Figure 2 An overall structural diagram of a system for improving the reliability of thermal two-out-of-three protection logic in a thermal power plant provided by an embodiment of the present invention.

[0034] Figure 3 A diagram of a first common protection construction method for a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant provided by an embodiment of the present invention.

[0035] Figure 4 A diagram of a second common protection construction method for a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant provided by an embodiment of the present invention.

[0036] Figure 5 A diagram of a third common protection construction method for a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant provided by an embodiment of the present invention.

[0037] Figure 6 A diagram of an optimized protection construction method for a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] Example 1, reference Figure 1 , which is an embodiment of the present invention, provides a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, comprising:

[0041] Performing quality judgment on the signals at the three measuring points as being over the limit and not bad, and generating a first signal, a second signal and a third signal;

[0042] Performing a bad quality judgment on the signals at the three measuring points to generate a fourth signal, a fifth signal and a sixth signal;

[0043] Inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module to generate a seventh signal;

[0044] Inputting the first signal, the second signal, the third signal and the seventh signal into a four-to-two module to generate an eighth signal;

[0045] The fourth signal, the fifth signal and the sixth signal are ANDed together to generate a ninth signal indicating that the detection point has completely failed;

[0046] The eighth signal and the ninth signal are ORed together to generate a tenth signal.

[0047] The judgment of over-limit and non-bad quality includes:

[0048] The analog signals of the three measuring points are judged for high and low limits. When the preset threshold is exceeded, the switch value 1 is output, and when the preset threshold is not exceeded, the switch value 0 is output.

[0049] The analog signal is transmitted to the quality judgment module. If the signal is of bad quality, the switch value 1 is output, and if the signal is of good quality, the switch value 0 is output;

[0050] Perform a negation operation on the output of the quality judgment module, converting 1 to 0 and 0 to 1;

[0051] The limit judgment result is ANDed with the quality judgment result after negation. When the signal exceeds the limit and is of good quality, the switch value 1 is output, and the switch value 0 is output in other cases.

[0052] Three switch signals are obtained, namely a first signal, a second signal and a third signal.

[0053] The bad quality judgment includes: judging the quality of the analog quantities of the three measuring points, if the signal is of bad quality, outputting the switch quantity 1, if the signal is of good quality, outputting the switch quantity 0, and obtaining three switch quantity signals, namely the fourth signal, the fifth signal and the sixth signal.

[0054] Generating the seventh signal includes inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module, and when at least two of the three input signals are 1, the fourth signal is output as 1, otherwise the output is 0.

[0055] Generating the eighth signal includes inputting the first signal, the second signal, the third signal and the seventh signal into a four-to-two module, and when at least two of the four input signals are 1, the fifth signal is output as 1, otherwise the output is 0.

[0056] Generating the ninth signal for detecting complete failure of the measuring point includes inputting the fourth signal, the fifth signal and the sixth signal into an AND module. When the three input signals are all 1, the ninth signal outputs 1, otherwise the output is 0.

[0057] Generating the tenth signal includes inputting the eighth signal and the ninth signal into an OR operation module, and when either the eighth signal or the ninth signal is 1, the tenth signal is output as 1, otherwise the tenth signal is output as 0.

[0058] Example 2, reference Figure 2 , which is an embodiment of the present invention, provides a system for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, comprising:

[0059] Data input layer 100, logic control layer 200 and output execution layer 300;

[0060] The data input layer 100 collects and pre-processes the measurement point signal data and transmits the processing results to the logic control layer 200;

[0061] The logic control layer 200 performs logic operations on the signals of the data input layer 100, generates the signals required by the protection logic, and determines whether the conditions for triggering the protection are met;

[0062] The output execution layer 300 triggers protection or alarm control according to the output signal of the logic control layer 200 .

[0063] The data input layer 100 includes an input acquisition module 101 , a limit determination module 102 , and a quality determination module 103 .

[0064] The logic control layer 200 includes a negation module 201 , a logic operation module 202 , a three-out-of-two module 203 , a four-out-of-two module 204 , an AND module 205 , and an OR module 206 .

[0065] The output execution layer 300 includes an alarm control module 301 .

[0066] The data input layer 100 is responsible for collecting and preliminarily processing the measurement point signals, generating signals for limit judgment and quality judgment, and transmitting them to the logic control layer.

[0067] The logic control layer 200 completes the logic processing of the signal, generates various signals, and finally outputs the seventh signal of protection triggering.

[0068] The output execution layer 300 triggers protection control based on the seventh signal state to achieve safety protection of thermal power plant equipment and improve system reliability.

[0069] Example 3

[0070] An embodiment of the present invention is different from the first two embodiments in that:

[0071] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0072] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0073] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0074] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0075] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0076] Example 4, reference Figure 3-Figure 5 , which is an embodiment of the present invention, provides a method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, comprising:

[0077] Common three-out-of-two protection logic construction methods in power plants are as follows: Figure 5~3 As shown, take the low level protection of the steam turbine lubricating oil tank as an example:

[0078] Figure 3 This is a common three-out-of-two protection construction method 1. The median value of three local lubricating oil tank level measurement points is taken and compared with the set value. If it is lower than the set value, the protection is triggered. The three-out-of-two module is usually a DCS built-in module with bad quality judgment and large deviation judgment functions. When one measurement point is bad, the logic is transformed into the average of the remaining two good points. When two points are bad, the logic is transformed into the remaining one good point. The disadvantages of this logic are: (1) The result after the three-out-of-two module is usually also used for unit analog quantity adjustment. During operation, a certain point may be selected according to the needs of the site to be fixed as the value after the three-out-of-two. If the fixed point sample suddenly leaks or the transmitter suddenly fails, the measured result may become 0 or a very small value, which will cause the protection to malfunction. (2) If one of the three measurement points is a bad point and is eliminated, the logic is transformed into a two-out-of-two average. Although one of the points is a good point, the measurement is inaccurate and becomes a maximum or minimum value. The result after the two-out-of-two average is also a maximum or minimum value, which will cause the protection to malfunction or refuse to operate. It can be seen from this that this method of using the three-out-of-three method instead of the three-out-of-two method has a great risk of false operation and refusal to operate.

[0079] Figure 4This is the common three-out-of-two protection construction method 2. Three local lubricating oil tank level measurement points are used to compare with the fixed value, and then the three-out-of-two protection is triggered. The main disadvantage of this logic is that there is no measurement point quality judgment: (1) If any of the three measurement points is of poor quality and the measured result becomes a small value, then any of the remaining two measurement points, if disturbed and fluctuated or the measurement point fails, may cause the protection to malfunction. (2) When two measurement points are of poor quality, if both measurement points become smaller, the protection will be malfunctioned directly; if both measurement points become larger, even if the third measurement point is a good point and the measured tank level is lower than the protection value, the protection will refuse to operate; if one of the two measurement points becomes larger and the other becomes smaller, the third point is disturbed and fluctuated, and the protection will malfunction. In summary, this construction method also has a great risk of malfunction and refusal to operate.

[0080] Figure 5 This is the common three-out-of-two protection construction method 3. After three local lubricating oil tank level measurement points are of good quality and below the limit, the three-out-of-two protection is triggered. Compared with method 2, although method 3 increases the quality judgment of the measurement points and reduces the probability of false protection operation, it increases the probability of protection refusal. When one point is of poor quality, the point is removed, and the protection logic is changed to two-out-of-two; when two points are of poor quality, the two points are removed, and the protection logic is changed to one-out-of-two, which will never be triggered, resulting in protection refusal. It can be seen that although the quality judgment is increased, the risk of protection refusal when two points are of poor quality increases.

[0081] In order to reduce the probability of protection misoperation or refusal to operate due to measurement point failure and improve the reliability of thermal power plant three-out-of-two protection logic, the present invention adopts the following technical solutions (such as Figure 6 ):

[0082] S1. Determine the bad quality of the original three measuring points, and use the over-limit value and non-bad quality phase of each measuring point to participate in the protection logic;

[0083] The original three measuring points (1-0, 2-0, 3-0) are analog signals and output signals (1-1, 2-1, 3-1) respectively. The analog signals are judged by the high and low limit modules (1-2, 2-2, 3-2) and the output switch quantity is 1 or 0 (1-3, 2-3, 3-3). The analog signals are judged by the quality module (1-4, 2-4, 3-4) and the output switch quantity is 1 or 0 (1-5, 2-5, 3-5), where 1 represents bad quality and 0 represents good quality. After the judgment by the negation module (1-6, 2-6, 3-6), the output switch quantity is 1 or 0 (1-7, 2-7, 3-7). After the signals 1-3 (2-3, 3-3) and 1-7 (2-7, 3-7) are judged by the module 1-8 (2-8, 3-8), the output switch value is 1 or 0 (S1-1, S1-2, S1-3).

[0084] S2, taking two out of the three original measuring points with bad quality signals as the fourth point to participate in the protection logic;

[0085] The original three measuring point bad quality signals are shown as 1-5, 2-5, 3-5 (connected to S2-1, S2-2, S2-3) as the three inputs of the three-out-of-two module S2. When two of the three input signals of the three-out-of-two module are 1, the output is 1, and the output signal is S2-4.

[0086] S3, change the original three-out-of-two judgment to four-out-of-two judgment;

[0087] Compared with traditional solutions ( Figure 5 4 in the figure is a three-out-of-two module), and S3 in this scheme is a four-out-of-two module. The four inputs of the four-out-of-two module are S1-1, S1-2, S1-3 and S2-4, and the output is 1 when two of the four input signals of the four-out-of-two module are 1.

[0088] S4, taking the bad quality signals of the original three measuring points and taking them as the fifth signal;

[0089] The original three measuring point bad quality signals are shown as 1-5, 2-5, 3-5 (connected to S4-1, S4-2, S4-3) as the three inputs of the AND module S4. When three of the three input signals of the AND module are 1, the output is 1, and the output signal is S4-4.

[0090] S5. OR the result of S3 and the result of S4 as the final protection signal.

[0091] The result S3 - 1 of S3 and the result S4 - 4 of S4 are coupled through an OR module S5 to obtain the final protection trigger signal S5 - 1 .

[0092] Compared with the prior art, the present invention has the following technical effects:

[0093] When one analog measurement point has poor quality, the logic changes to two-out-of-two; when two analog measurement points have poor quality, the logic changes to one-out-of-one; when three analog measurement points have poor quality, the protection is directly triggered.

[0094] It can be seen that the three-out-of-two configuration logic of the present invention, when two measuring points are of poor quality, the remaining measuring point still plays a protective role, which can prevent the harm caused by protection refusal. When the three measuring points are of poor quality, it is equivalent to the DCS monitoring of this parameter out of control, and the power is directly shut down. Whether to directly shut down when the three points are of poor quality can be selected according to the specific situation of the power plant. The present invention only provides a configuration method when direct shutdown is required. If shutdown is not required, it can only be used for the first-level alarm.

[0095] Example 5, reference Figure 3-Figure 5, which is an embodiment of the present invention, provides a method for improving the reliability of the thermal three-out-of-two protection logic of a thermal power plant. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through simulation experiments.

[0096] Experimental conditions: Provide three lubricating oil level simulation measurement points.

[0097] Experimental requirements: Build the low level protection logic for the lubricating oil tank. When the liquid level is lower than 1000mm, the protection will be activated to minimize the risk of false protection and refusal to operate.

[0098] Experiment 1: Figure 5 Take the traditional three-out-of-two protection logic construction method 3 as an example to build the protection logic.

[0099] (1) When the three measuring points (lubricating oil tank level measuring points 1 to 3) are all good points, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 990 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 1003 mm.

[0100] ① The result of block 1-0 after passing through comparison module 1-1 is 1; the result of block 1-0 after passing through bad quality judgment module 1-2 is 0, and then after passing through negation module 1-3, the result is 1; the above two output results are passed through AND block 1-4, and the result is 1, which is used as input 1 of module 4;

[0101] ② The result of block 2-0 after comparison module 2-1 is 1; the result of block 2-0 after bad quality judgment module 2-2 is 0, and then after negation module 2-3 the result is 1; the above two output results are passed through AND block 2-4 and the result is 1, which is used as input 2 of module 4;

[0102] ③ The result of block 3-0 after comparison module 3-1 is 0; the result of block 3-0 after bad quality judgment module 3-2 is 0, and then after negation module 3-3 the result is 1; the above two output results are ANDed with block 3-4 and the result is 0, which is used as input 3 of module 4;

[0103] ④ Block 4 is a two-out-of-three module. When two of the three inputs are 1, the output is 1. In this experiment, two of the inputs of block 4 are 1, so the output is 1.

[0104] Experimental results: When the three measurement points are of good quality, the protection logic results can be output correctly.

[0105] (2) When the lubricating oil tank level measuring points 1 and 2 are good points and the lubricating oil tank level measuring point 3 is a bad point, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 990 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0 mm.

[0106] ① The result of block 1-0 after passing through comparison module 1-1 is 1; the result of block 1-0 after passing through bad quality judgment module 1-2 is 0, and then after passing through negation module 1-3, the result is 1; the above two output results are passed through AND block 1-4, and the result is 1, which is used as input 1 of module 4;

[0107] ② The result of block 2-0 after comparison module 2-1 is 1; the result of block 2-0 after bad quality judgment module 2-2 is 0, and then after negation module 2-3 the result is 1; the above two output results are passed through AND block 2-4 and the result is 1, which is used as input 2 of module 4;

[0108] ③ The result of block 3-0 after comparison module 3-1 is 1; the result of block 3-0 after bad quality judgment module 3-2 is 1, and then after negation module 3-3 the result is 0; the above two output results are 0 after AND block 3-4, which is used as input 3 of module 4;

[0109] ④ Block 4 is a two-out-of-three module. When two of the three inputs are 1, the output is 1. In this experiment, two of the inputs of block 4 are 1, so the output is 1.

[0110] Experimental results: When one of the three measuring points is of poor quality and the other two are of good quality, the protection logic is equivalent to taking two out of the remaining two good points. When the lubricating oil tank level is lower than 1000mm, the protection logic result can still be output correctly.

[0111] (3) When the lubricating oil tank level measuring point 1 is a good point and the lubricating oil tank level measuring points 2 and 3 are bad points, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 0 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0 mm.

[0112] ① The result of block 1-0 after passing through comparison module 1-1 is 1; the result of block 1-0 after passing through bad quality judgment module 1-2 is 0, and then after passing through negation module 1-3, the result is 1; the above two output results are passed through AND block 1-4, and the result is 1, which is used as input 1 of module 4;

[0113] ② The result of block 2-0 after comparison module 2-1 is 1; the result of block 2-0 after bad quality judgment module 2-2 is 1, and then after negation module 2-3 the result is 0; the above two output results are ANDed with block 2-4 and the result is 0, which is used as input 2 of module 4;

[0114] ③ The result of block 3-0 after comparison module 3-1 is 1; the result of block 3-0 after bad quality judgment module 3-2 is 1, and then after negation module 3-3 the result is 0; the above two output results are 0 after AND block 3-4, which is used as input 3 of module 4;

[0115] ④ Block 4 is a three-out-of-two module. When two of the three inputs are 1, the output result is 1. In this experiment, only one of the inputs of block 4 is 1, so the output result is 0.

[0116] Experimental results: When two of the three measuring points are of poor quality and the other one is of good quality, the protection logic is equivalent to taking two out of the remaining good point, and the protection cannot be triggered. When the lubricating oil tank level is lower than 1000mm, the protection refuses to work and can never be triggered.

[0117] (4) When the lubricating oil tank level measuring points 1 to 3 are all of bad quality, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 0mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 0mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0mm.

[0118] ① The result of block 1-0 after comparison module 1-1 is 1; the result of block 1-0 after bad quality judgment module 1-2 is 1, and then after negation module 1-3 the result is 0; the above two output results are ANDed with block 1-4 and the result is 0, which is used as input 1 of module 4;

[0119] ② The result of block 2-0 after comparison module 2-1 is 1; the result of block 2-0 after bad quality judgment module 2-2 is 1, and then after negation module 2-3 the result is 0; the above two output results are ANDed with block 2-4 and the result is 0, which is used as input 2 of module 4;

[0120] ③ The result of block 3-0 after comparison module 3-1 is 1; the result of block 3-0 after bad quality judgment module 3-2 is 1, and then after negation module 3-3 the result is 0; the above two output results are 0 after AND block 3-4, which is used as input 3 of module 4;

[0121] ④ Block 4 is a three-out-of-two module. When two of the three inputs are 1, the output result is 1. In this experiment, the inputs of block 4 are all 0, so the output result is 0.

[0122] Experimental results: When the three measuring points are of bad quality and the liquid level in the lubricating oil tank is lower than 1000mm, the protection will refuse to work and will never be triggered.

[0123] Experiment 2: Figure 6 The solution of the present invention builds protection logic.

[0124] (1) When the three measuring points (lubricating oil tank level measuring points 1 to 3) are all good points, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 990 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 1003 mm.

[0125] ① The logical judgment in the S1 module is the same as that in Experiment 1, so I will not repeat it here. The result of S1-1 is 1, the result of S1-2 is 1, and the result of S1-3 is 0.

[0126] ②The result of S2-1 is 0, the result of S2-2 is 0, and the result of S2-3 is 0. After the three signals are processed by the three-to-two module, the result of S2 is 0, and the result of S2-4 is 0.

[0127] ③The four signals S1-1, S1-2, S1-3, and S2-4 pass through the four-to-two module, and the result of S3 is 1, and the result of S3-1 is 1.

[0128] ④The result of S4-1 is 0, the result of S4-2 is 0, and the result of S4-3 is 0. After the above three signals pass through the AND module S4, the result is 0, and the result of S4-4 is 0.

[0129] ⑤The two signals S3-1 and S4-4 are ORed by the module S5 and the result is 1.

[0130] Experimental results: When the three measurement points are of good quality, the protection logic results can be output correctly.

[0131] (2) When the lubricating oil tank level measuring points 1 and 2 are good points and the lubricating oil tank level measuring point 3 is a bad point, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 990 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0 mm.

[0132] ① The logical judgment in the S1 module is the same as that in Experiment 1, so I will not repeat it here. The result of S1-1 is 1, the result of S1-2 is 1, and the result of S1-3 is 0.

[0133] ②The result of S2-1 is 0, the result of S2-2 is 0, and the result of S2-3 is 1. After the three signals pass through the three-to-two module, the result of S2 is 0, and the result of S2-4 is 0.

[0134] ③The four signals S1-1, S1-2, S1-3, and S2-4 pass through the four-to-two module, and the result of S3 is 1, and the result of S3-1 is 1.

[0135] ④The result of S4-1 is 0, the result of S4-2 is 0, and the result of S4-3 is 1. After the three signals pass through the AND module S4, the result is 0, and the result of S4-4 is 0.

[0136] ⑤The two signals S3-1 and S4-4 pass through the phase OR module S5 and the result is 1.

[0137] Experimental results: When one of the three measuring points is of poor quality and the other two are of good quality, the protection logic is equivalent to taking two out of the remaining two good points. When the lubricating oil tank level is lower than 1000mm, the protection logic result can still be output correctly.

[0138] (3) When the lubricating oil tank level measuring point 1 is a good point and the lubricating oil tank level measuring points 2 and 3 are bad points, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 980 mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 0 mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0 mm.

[0139] ① The logical judgment in the S1 module is the same as that in Experiment 1 and will not be repeated here. The result of S1-1 is 1, the result of S1-2 is 0, and the result of S1-3 is 0.

[0140] ②The result of S2-1 is 0, the result of S2-2 is 1, and the result of S2-3 is 1. After the three signals are processed by the three-to-two module, the result of S2 is 1, and the result of S2-4 is 1.

[0141] ③The four signals S1-1, S1-2, S1-3, and S2-4 pass through the four-to-two module, and the result of S3 is 1, and the result of S3-1 is 1.

[0142] ④The result of S4-1 is 0, the result of S4-2 is 1, and the result of S4-3 is 1. After the three signals pass through the AND module S4, the result is 0, and the result of S4-4 is 0.

[0143] ⑤The two signals S3-1 and S4-4 pass through the phase OR module S5 and the result is 1.

[0144] Experimental results: When two of the three measuring points are of bad quality and the other one is of good quality, the protection logic is equivalent to taking one from the remaining good point. When the lubricating oil tank level is lower than 1000mm, the protection can still be triggered correctly.

[0145] (4) When the lubricating oil tank level measuring points 1 to 3 are all of bad quality, the measurement value of the lubricating oil tank level measuring point 1 (block 1-0) is 0mm, the measurement value of the lubricating oil tank level measuring point 2 (block 2-0) is 0mm, and the measurement value of the lubricating oil tank level measuring point 3 (block 3-0) is 0mm.

[0146] ① The logical judgment in the S1 module is the same as that in Experiment 1, so I will not repeat it here. The result of S1-1 is 0, the result of S1-2 is 0, and the result of S1-3 is 0.

[0147] ②The result of S2-1 is 1, the result of S2-2 is 1, and the result of S2-3 is 1. After the three signals are processed by the two-out-of-three module, the result of S2 is 1, and the result of S2-4 is 1.

[0148] ③ The four signals S1-1, S1-2, S1-3, and S2-4 pass through the four-to-two module, and the result of S3 is 0, and the result of S3-1 is 0.

[0149] ④The result of S4-1 is 1, the result of S4-2 is 1, and the result of S4-3 is 1. After the above three signals pass through the AND module S4, the result is 1, and the result of S4-4 is 1.

[0150] ⑤The two signals S3-1 and S4-4 pass through the phase OR module S5 and the result is 1.

[0151] Experimental results: When the three measuring points are all of bad quality, it is equivalent to the DCS monitoring this parameter out of control, and the power is directly shut down. Whether to directly shut down when the three points are of bad quality can be selected according to the specific situation of the power plant. The present invention only provides a configuration method when direct shutdown is required. If shutdown is not required, it can only be used for the first-level alarm.

[0152] Comparing Experiment 1 and Experiment 2, under conditions (1) and (2), both schemes can correctly trigger protection; under condition (3), the traditional scheme will refuse to protect, while the protection of the scheme of the present invention can still act correctly according to the actual situation; under condition (4), the traditional scheme will refuse to protect, while the scheme of the present invention can issue a first-level alarm or directly trigger protection according to the requirements of the power plant. It can be seen that the protection logic constructed by the scheme of the present invention is more reliable.

[0153] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for improving the reliability of thermal three-out-of-two protection logic in a thermal power plant, characterized in that: include: Performing quality judgment on the signals at the three measuring points as being over the limit and not bad, and generating a first signal, a second signal and a third signal; Performing a bad quality judgment on the signals at the three measuring points to generate a fourth signal, a fifth signal and a sixth signal; Inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module to generate a seventh signal; Inputting the first signal, the second signal, the third signal and the seventh signal into a four-to-two module to generate an eighth signal; The fourth signal, the fifth signal and the sixth signal are ANDed together to generate a ninth signal indicating that the detection point has completely failed; The eighth signal and the ninth signal are ORed together to generate a tenth signal.

2. The method for improving the reliability of thermal power plant three-out-of-two protection logic according to claim 1, characterized in that: The above-limit and non-bad quality judgment includes: The analog signals of the three measuring points are judged for high and low limits. When the preset threshold is exceeded, the switch value 1 is output, and when the preset threshold is not exceeded, the switch value 0 is output. The analog signal is transmitted to the quality judgment module. If the signal is of bad quality, the switch value 1 is output, and if the signal is of good quality, the switch value 0 is output; Perform a negation operation on the output of the quality judgment module, converting 1 to 0 and 0 to 1; The limit judgment result is ANDed with the quality judgment result after negation. When the signal exceeds the limit and is of good quality, the switch value 1 is output, and the switch value 0 is output in other cases. Three switch signals are obtained, namely a first signal, a second signal and a third signal.

3. The method for improving the reliability of thermal power plant three-out-of-two protection logic according to claim 2, characterized in that: The bad quality judgment includes: judging the quality of the analog quantities of the three measuring points, outputting a switch quantity 1 if the signal is of bad quality, and outputting a switch quantity 0 if the signal is of good quality, and obtaining three switch quantity signals, namely the fourth signal, the fifth signal and the sixth signal. Generating the seventh signal includes inputting the fourth signal, the fifth signal and the sixth signal into a three-to-two module, and when at least two of the three input signals are 1, the fourth signal is output as 1, otherwise the output is 0.

4. The method for improving the reliability of thermal power plant three-out-of-two protection logic according to claim 3, characterized in that: Generating the eighth signal includes inputting the first signal, the second signal, the third signal and the seventh signal into a four-to-two module, and when at least two of the four input signals are 1, the fifth signal is output as 1, otherwise the output is 0.

5. The method for improving the reliability of thermal power plant three-out-of-two protection logic according to claim 4, characterized in that: The generating of the ninth signal for detecting the complete failure of the measuring point comprises inputting the fourth signal, the fifth signal and the sixth signal into an AND module, and when the three input signals are all 1, the ninth signal outputs 1, otherwise the output is 0.

6. The method for improving the reliability of thermal power plant three-out-of-two protection logic according to claim 5, characterized in that: The generating of the tenth signal includes inputting the eighth signal and the ninth signal into an OR operation module, and when either the eighth signal or the ninth signal is 1, the tenth signal is output as 1, otherwise the tenth signal is output as 0.

7. A system using the method for improving the reliability of thermal power plant three-out-of-two protection logic as claimed in any one of claims 1 to 6, characterized in that: include: Data input layer (100), logic control layer (200) and output execution layer (300); The data input layer (100) collects and pre-processes the measurement point signal data, and transmits the processing results to the logic control layer (200); The logic control layer (200) performs logic operation processing on the signal of the data input layer (100), generates the signal required by the protection logic, and determines whether the conditions for triggering protection are met; The output execution layer (300) triggers protection or alarm control according to the output signal of the logic control layer (200).

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for improving the reliability of thermal three-out-of-two protection logic of a thermal power plant as described in any one of claims 1 to 6 are implemented.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for improving the reliability of the thermal two-out-of-three protection logic of a thermal power plant according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for improving the reliability of thermal three-out-of-two protection logic of a thermal power plant according to any one of claims 1 to 6 are implemented.

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