A high-low bypass combined heat supply working condition high discharge pressure automatic control method of a steam turbine

Abstract

An automatic control method for high-pressure exhaust pressure under combined high- and low-pressure turbine heating operation is disclosed, relating to the field of heating unit technology. The method includes acquiring a first adjustment parameter, a second adjustment parameter, a third adjustment parameter, and a high-pressure exhaust value; generating corresponding first, second, and third adjustment targets based on the first, second, and third adjustment parameters; determining whether the real-time acquired high-pressure exhaust value exceeds the safety range of the first adjustment target; if it does, adjusting the opening of the regulating valve to ensure that the adjusted high-pressure exhaust value satisfies the corresponding combination of the first, second, or third adjustment targets under different conditions; if it does not exceed the safety range, continuing to monitor the high-pressure exhaust value. This method can solve the problem of inaccurate high-pressure exhaust adjustment results.

Description

Technical Field

[0001] This invention relates to the field of heating unit technology, specifically to an automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine. Background Technology

[0002] Under the "dual carbon" background, in order to solve the problem of new energy power consumption, thermal power generating units, which account for the largest proportion, need to undertake more peak shaving tasks, while also taking into account the needs of industry, people's livelihood and heating. Especially in winter, heating becomes one of the important tasks. Traditional thermal power generating units have limited heating capacity when operating at low load, while the use of high-low bypass combined heating technology can enhance this capacity.

[0003] The combined high- and low-pressure bypass heating technology for steam turbines reduces the amount of steam entering the turbine's three cylinders by adjusting the bypass steam flow rate. This allows excess steam to be used for heating without affecting power production, thereby improving the unit's heating capacity during low-load operation and meeting the heating demand during deep peak shaving operation.

[0004] When the turbine is used for combined high-pressure and low-pressure bypass heating, the high-pressure exhaust pressure will decrease, and the last stage blades of the high-pressure cylinder will be subjected to a greater pressure difference before and after, which will greatly increase the safety risk of blade operation. Therefore, by using the intermediate control valve to adjust or matching the high-pressure and low-pressure bypass flow, the high-pressure exhaust pressure is kept within the safe range under the corresponding load, so as to ensure the safe operation of the turbine unit when the turbine is used for combined high-pressure and low-pressure bypass heating.

[0005] Traditionally, the high-pressure exhaust is adjusted to a suitable value based on experience by adjusting the size of the intermediate regulating valve. However, this method is not suitable for inexperienced workers, and the high-pressure exhaust value adjusted based on experience may affect the turbine because there are few reference factors.

[0006] Chinese patent CN113266435B discloses a method and apparatus for adjusting high-pressure discharge using a medium-pressure regulating valve. This method determines whether to open or close the regulating valve to adjust the high-pressure discharge by judging whether the high-pressure discharge exceeds an upper limit or falls below a lower limit. After adjusting the regulating valve, it again judges whether the high-pressure discharge exceeds the upper limit or falls below the lower limit to determine the degree of adjustment. Therefore, this method has poor accuracy in judging the high-pressure discharge. Furthermore, the steps involved in adjusting the high-pressure discharge are cumbersome, as the adjustment process also affects the turbine's operation; thus, the cumbersome operation can negatively impact the turbine's performance.

[0007] Therefore, we propose a method that can precisely control the adjustment of high-pressure emissions. Summary of the Invention

[0008] The purpose of this invention is to provide an automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of steam turbines, which is used to solve the problem of inaccurate high-pressure exhaust pressure adjustment results.

[0009] This invention is achieved through the following technical solution:

[0010] An automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine includes:

[0011] Obtain the first adjustment parameter, the second adjustment parameter, the third adjustment parameter, and the high-pressure value;

[0012] Based on the first adjustment parameter, the second adjustment parameter, and the third adjustment parameter, corresponding first adjustment target, second adjustment target, and third adjustment target are generated respectively.

[0013] Determine whether the real-time high exhaust pressure value exceeds the safe range in the first regulation target;

[0014] If the pressure exceeds the limit, adjust the opening of the regulating valve and ensure that the high-pressure value after regulation meets the corresponding combination of the first regulation target, the second regulation target, or the third regulation target under different conditions.

[0015] If the pressure does not exceed the limit, continue monitoring the high-pressure value.

[0016] Furthermore, the first adjustment parameters include the pressure after the adjustment stage, the low alarm parameter, and the high alarm parameter. The first adjustment target is a safe range control function, and the expression of the safe range control function f(x) is:

[0017] f(x) = mX + b;

[0018] Where X is the pressure after the regulating stage, m is the slope, and b is the intercept;

[0019] The safety range is [f(x)-α,f(x)+β], where α and β are the low alarm parameter and the high alarm parameter, respectively.

[0020] Furthermore, the second regulating parameter includes the high bypass inlet steam flow rate H. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c The second adjustment target is the matching relationship between high and low bypass steam flow rates, and the expression for this matching relationship is:

[0021] H a +H b =H c .

[0022] Furthermore, the third adjustment parameter includes the pressure after the adjustment stage, and the third adjustment target is the high-pressure cylinder pressure ratio U, specifically expressed as:

[0023]

[0024] Where X is the pressure after the regulating stage, and Y is the high-pressure value.

[0025] Furthermore, when the load change rate of the unit is less than 10%, the high exhaust pressure value after regulation is made to be within the safe range [f(x)-α,f(x)+β] of the safe range control function.

[0026] Furthermore, when the unit's operating condition is relatively stable, the high bypass inlet steam flow H is affected by the high exhaust pressure after regulation. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c It is necessary to meet the matching relationship between high and low steam flow rates.

[0027] Furthermore, when the steam turbine is in the range of 70% to 40% of the electrical load and the boiler load is in the range of 70% to 60%, the high-pressure discharge pressure value after adjustment is used to make the calculated high-pressure cylinder pressure ratio fall within (3.5, 4.5).

[0028] Furthermore, when the unit's load changes by more than 20% or the heating demand changes, the adjusted high-pressure discharge value needs to simultaneously meet the first and second adjustment targets.

[0029] Furthermore, when the steam turbine is in the range of 70% to 40% of the electrical load, the boiler load is in the range of 70% to 60%, and the load variation of the unit is less than 10%, the high-pressure exhaust value after regulation needs to simultaneously meet the first regulation target and the third regulation target.

[0030] Furthermore, when frequent adjustments to load or heating demand are required, the adjusted high-pressure value needs to simultaneously meet both the second and third adjustment targets.

[0031] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0032] This invention discloses an automatic control method for high exhaust pressure under combined high and low pressure bypass heating of a steam turbine. By using a combination of multiple adjustment targets, the accuracy of the high exhaust pressure value can be effectively improved, thereby ensuring that the unit can operate safely when the steam turbine is in combined high and low pressure bypass heating.

[0033] In addition, by applying different control targets to the high exhaust pressure value under different turbine conditions, the accuracy of the controlled high exhaust pressure value can be further improved, effectively balancing the power supply and heating work of the thermal power generating unit. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the method flow of the present invention;

[0035] Figure 2 This is a schematic diagram of the system structure in this invention;

[0036] Figure 3 This is a schematic diagram of the electronic device in this invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0041] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Example 1

[0043] As attached Figure 1 The method for automatic control of high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine includes:

[0044] Obtain the first adjustment parameter, the second adjustment parameter, the third adjustment parameter, and the high-pressure value;

[0045] Based on the first adjustment parameter, the second adjustment parameter, and the third adjustment parameter, corresponding first adjustment target, second adjustment target, and third adjustment target are generated respectively.

[0046] Among them, the high exhaust pressure value is the parameter value that needs to be regulated. The first regulation target is calculated based on the first regulation parameter, the second regulation target is calculated based on the second regulation parameter, and the third regulation target is calculated based on the third regulation parameter. By ensuring that the regulated high exhaust pressure value can directly or indirectly meet the requirements of the first regulation target, the second regulation target, and the third regulation target, it is ensured that the regulated high exhaust pressure value can enable the thermal power generating unit to maintain good heating and power supply at the same time.

[0047] In addition, the first adjustment parameters include the pressure after the adjustment stage, the low alarm parameter, and the high alarm parameter. The first adjustment target is a safe range control function, and the expression of the safe range control function f(x) is:

[0048] f(x) = mX + b;

[0049] Where X is the pressure after the regulating stage, m is the slope, and b is the intercept;

[0050] The safe range is [f(x)-α,f(x)+β], where α and β are the low alarm parameter and the high alarm parameter, respectively; that is, the first adjustment target is to determine a safe control range, and ensure that the high exhaust pressure value after adjustment is within the safe control range, so as to meet the requirements of the thermal power generating unit.

[0051] In addition, tests were conducted in the range of 70% to 40% of the electrical load of the supercritical 350MW steam turbine and 70% to 60% of the boiler load, and the values ​​of α and β were found to be 0.2 and 0.4, respectively, that is, the safe range is [f(x)-0.2,f(x)+0.4].

[0052] In addition, the second adjustment parameter includes a high bypass inlet steam flow rate H. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c The second adjustment target is the matching relationship between high and low bypass steam flow rates, and the expression for this matching relationship is:

[0053] H a +H b =H c ;

[0054] The second regulation target is used to indirectly estimate the control result of the high exhaust pressure value, due to the high bypass inlet steam flow rate H. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c All three parameters in the second adjustment parameter can be calculated by the flow meter. During the adjustment of the high discharge pressure value, the three parameters in the second adjustment parameter are monitored in real time and judged according to the expression. When the expression is true, the adjustment of the high discharge pressure value can be stopped, indicating that the high discharge pressure value has been adjusted in place.

[0055] It should be noted that the high exhaust pressure value is controlled by adjusting the opening of the intermediate regulating valve;

[0056] As needed, the third adjustment parameter includes the pressure after the adjustment stage, and the third adjustment target is the high-pressure cylinder pressure ratio U, specifically expressed as:

[0057]

[0058] Where X is the pressure after the regulating stage, and Y is the high-pressure value;

[0059] It should be noted that the high-pressure cylinder pressure ratio U was also obtained by testing in the range of 70% to 40% of the supercritical 350MW steam turbine electrical load and 70% to 60% of the boiler load. Because the test basically represents the full-load operation of the generator set, the results obtained are relatively accurate, specifically (3.5, 4.5).

[0060] Determine whether the real-time high exhaust pressure value exceeds the safe range in the first regulation target;

[0061] If the pressure exceeds the limit, the opening of the regulating valve will be adjusted to ensure that the adjusted high-pressure value meets the corresponding combination of the first, second, or third regulation targets under different conditions. The specific combination can be any one of the first, second, or third regulation targets individually, or a combination of the first and second targets, the first and third targets, or the third and second targets, or a combination of the first, second, and third regulation targets. It should be noted that the specific combination chosen will be determined based on the operating conditions of the thermal power generating unit.

[0062] If the pressure does not exceed the limit, continue monitoring the high-pressure value. At this time, there is no need to adjust the opening of the intermediate regulating valve; maintain the current high-pressure value.

[0063] Example 2

[0064] When the load change rate of the unit is less than 10%, the high exhaust pressure value after regulation only needs to meet the first regulation target. Specifically, the high exhaust pressure value after regulation should be within the safe range [f(x)-α,f(x)+β] of the safe range control function. Based on the test results of the supercritical 350MW steam turbine with an electrical load of 70% to 40% and a boiler load of 70% to 60%, the values ​​of α and β are 0.2 and 0.4, respectively, that is, the safe range is [f(x)-0.2,f(x)+0.4].

[0065] Furthermore, since the first regulation target, the expression of the safe range control function f(x) is a linear equation, the specific expression of the safe range control function f(x) can be obtained from the given data of the two sets of regulating stage downstream pressure (MPa) X and high-pressure exhaust pressure (MPa) during implementation. For example, if the two sets of regulating stage downstream pressure (MPa) X and high-pressure exhaust pressure (MPa) data are (11.19, 2.8) and (15.96, 3.59), then...

[0066] f(x) = 0.17X + 0.95;

[0067] The safe range can be obtained by substituting the adjusted high-pressure value into the expression for the pressure (MPa)X after the adjustment stage. This allows us to determine whether the adjusted high-pressure value is within the safe range.

[0068] When the unit's operating condition is relatively stable, the adjusted high-pressure discharge value only needs to meet the second adjustment target, which is the high-bypass steam flow rate H affected by the adjusted high-pressure discharge. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c It is necessary to meet the matching relationship between high and low steam flow rates.

[0069] When the steam turbine is in the range of 70% to 40% of the electrical load and the boiler load is in the range of 70% to 60%, the high-pressure discharge pressure value after regulation only needs to meet the third regulation target. That is, the high-pressure cylinder pressure ratio calculated after regulation is placed in the range of (3.5, 4.5).

[0070] Example 3

[0071] When the unit load fluctuates by more than 20% or the heating demand changes, the adjusted high-pressure discharge value needs to simultaneously meet the first and second adjustment targets; that is, the adjusted high-pressure discharge value must be within the safe range, and the high-pressure bypass inlet steam flow rate H affected by the adjusted high-pressure discharge must also meet the first and second adjustment targets. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H cFurthermore, it is necessary to meet the matching relationship between high and low steam flow rates; because the combination of the two methods can provide more precise control under conditions of rapid load changes.

[0072] When the turbine is operating at 70%–40% of its electrical load, the boiler load is operating at 70%–60% of its load, and the unit load variation is less than 10%, the adjusted high-pressure discharge value must simultaneously meet both the first and third adjustment targets. That is, the adjusted high-pressure discharge value must be within the corresponding safe range, and the high-pressure cylinder pressure ratio calculated based on the adjusted high-pressure discharge pressure must be within (3.5, 4.5). This ensures that the unit can maintain safe and efficient operation even under complex and variable operating conditions.

[0073] Furthermore, when frequent adjustments to load or heating demand are required, the regulated high-pressure discharge value needs to simultaneously meet both the second and third regulation objectives; that is, it needs to meet both the high bypass inlet steam flow rate H, which is affected by the regulated high-pressure discharge. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c To ensure that the high and low steam flow rates are matched, and that the high pressure cylinder pressure ratio calculated based on the adjusted high exhaust pressure is within the range of (3.5, 4.5), the generator's heating capacity must meet the requirements.

[0074] Example 4

[0075] When the unit faces extreme operating conditions, such as deep peak shaving, rapid start-up and shutdown, or other situations that may cause drastic fluctuations in high-pressure exhaust, it needs to simultaneously meet three control objectives: that is, the high-pressure exhaust value after control is within a safe range, and the high-pressure bypass inlet steam flow H affected by the high-pressure exhaust after control is within a safe range. a High-pressure desuperheating water flow rate H b and low bypass inlet steam flow rate H c This ensures the matching relationship between high and low steam flow rates, and the high-pressure cylinder pressure ratio calculated based on the adjusted high exhaust pressure is within the range of (3.5, 4.5). This maximizes the safety and stability of the unit, especially during critical moments when the high exhaust pressure is highly sensitive.

[0076] Example 5

[0077] As attached Figure 2 The automatic control system for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating of a steam turbine includes a parameter acquisition module, a first calculation module, a second calculation module, a third calculation module, a judgment module, and a control module.

[0078] The parameter acquisition module is used to acquire the first adjustment parameter, the second adjustment parameter, the third adjustment parameter, and the high discharge pressure value;

[0079] The first calculation module is used to calculate the first control target based on the first adjustment parameter;

[0080] The second calculation module is used to calculate the second control target based on the second adjustment parameter;

[0081] The third calculation module is used to calculate the third control target based on the third adjustment parameter;

[0082] The judgment module is used to determine whether the high-pressure value acquired in real time exceeds the safe range in the first adjustment target;

[0083] The control module is used to change the opening of the intermediate control valve according to the result of the judgment module, and, in combination with different conditions of the generator set, call the parameter to obtain the high exhaust pressure value in the module, and make the high exhaust pressure value satisfy the corresponding combination of the result of the first calculation module, the result of the second calculation module, or the result of the third calculation module.

[0084] Example 6

[0085] As attached Figure 3 An electronic device is shown, characterized in that it comprises:

[0086] Processor, memory, communication interface;

[0087] The memory is used to store the executable instructions of the processor;

[0088] The processor is configured to execute the above-mentioned automatic control method for high-pressure exhaust under combined high- and low-pressure turbine heating conditions by executing the executable instructions.

[0089] A readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the above-mentioned automatic control method for high-pressure exhaust under combined high- and low-pressure steam turbine heating conditions.

[0090] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for automatic control of high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine, characterized in that: include: Obtain the first adjustment parameter, the second adjustment parameter, the third adjustment parameter, and the high-pressure value; Based on the first adjustment parameter, the second adjustment parameter, and the third adjustment parameter, corresponding first adjustment target, second adjustment target, and third adjustment target are generated respectively. The first adjustment parameters include the pressure after the adjustment stage, the low alarm parameter, and the high alarm parameter. The first adjustment target is a safe range control function. The expression is: ； in To regulate the pressure after the stage, The slope The intercept; The security range is: ,in and These are the low alarm parameters and the high alarm parameters, respectively. The second regulating parameter includes high bypass inlet steam flow rate. High bypass desuperheating water flow rate and low bypass inlet steam flow The second adjustment target is the matching relationship between high and low bypass steam flow rates, and the expression for this matching relationship is: ； Determine whether the real-time high exhaust pressure value exceeds the safe range in the first regulation target; If the pressure exceeds the limit, adjust the opening of the regulating valve and ensure that the high-pressure value after regulation meets the corresponding combination of the first regulation target, the second regulation target, or the third regulation target under different conditions. If it does not exceed the limit, continue monitoring the high-pressure value.

2. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine as described in claim 1, characterized in that: The third adjustment parameter includes the pressure after the adjustment stage, and the third adjustment target is the high-pressure cylinder pressure ratio. The specific expression is: ； in, To regulate the pressure after the stage, This is the high discharge pressure value.

3. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine as described in claim 2, characterized in that: When the load change rate of the unit is less than 10%, the adjusted high-pressure exhaust value is kept within the safe range of the control function. Inside.

4. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine as described in claim 2, characterized in that: When the unit is operating in a relatively stable state, the high bypass inlet steam flow is affected by the high exhaust pressure after regulation. High bypass desuperheating water flow rate and low bypass inlet steam flow It is necessary to meet the matching relationship between high and low steam flow rates.

5. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine according to claim 2, characterized in that: When the steam turbine is operating at 70%–40% of its electrical load and the boiler load is operating at 70%–60%, the calculated high-pressure cylinder pressure ratio is maintained by using the adjusted high-pressure exhaust pressure value. middle.

6. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine according to claim 2, characterized in that: When the unit's load changes by more than 20% or the heating demand changes, the adjusted high-pressure discharge value needs to simultaneously meet the first and second adjustment targets.

7. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine as described in claim 2, characterized in that: When the steam turbine is in the range of 70% to 40% of the electrical load, the boiler load is in the range of 70% to 60%, and the load variation of the unit is less than 10%, the high-pressure discharge value after regulation needs to meet both the first and third regulation targets at the same time.

8. The automatic control method for high-pressure exhaust pressure under combined high-pressure and low-pressure bypass heating conditions of a steam turbine according to claim 2, characterized in that: When frequent adjustments to load or heating demand are required, the adjusted high-pressure value must simultaneously meet both the second and third adjustment targets.

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