Thermal power generating unit steam turbine heat supply control method

Abstract

The thermal power generating unit steam turbine heat supply control method provided by the embodiment of the invention comprises the following steps: entering a corresponding logic control layer according to the operation condition and a control instruction of a thermal power generating unit; and according to preset adjusting logic in the logic control layer, the opening and closing state of a valve of a steam turbine in the thermal power generating unit corresponding to the logic control layer is adjusted, so that the steam turbine enters the corresponding working condition. According to the control method provided by the invention, the flow of the steam energy between the medium-pressure cylinder and the low-pressure cylinder of the thermal power generating unit is controlled, and the generating capacity and the heat supply capacity of the low-pressure cylinder of the steam turbine of the thermal power generating unit can be adjusted, so that the generating capacity and the heat supply capacity are regulated and controlled.

Description

Technical Field

[0001] This disclosure relates to the field of heating in thermal power plants, and more particularly to a method for controlling the heating of a steam turbine in a thermal power unit. Background Technology

[0002] Currently, most thermal power generating units in northern my country are responsible for winter heating. In the existing heating model, power generation and heat supply are positively correlated: increasing the heating load requires increasing boiler steam output and correspondingly increasing power supply load; that is, increased heat supply inevitably leads to increased power generation. However, a significant supply-demand mismatch exists in northern winters: on the one hand, overall electricity consumption is lower in winter than in summer; on the other hand, peak heating demand is concentrated at night when power demand is low, while peak power demand occurs during the day when heating demand is low. This creates a supply-demand contradiction between power generation and heat supply. Given the necessity of ensuring sufficient heat supply, it is urgent to explore an operating model that can achieve more heat supply and less power generation to resolve this supply-demand contradiction and maximize economic benefits while ensuring the heating needs of residents. Summary of the Invention

[0003] This disclosure provides a method for controlling the heating supply of a steam turbine in a thermal power unit, which is used to resolve the supply and demand contradiction between power generation and heating supply in a heating mode.

[0004] Based on the above problems, in a first aspect, the present disclosure provides a method for controlling the heating supply of a steam turbine in a thermal power unit, comprising: Based on the operating status and control commands of the thermal power unit, the system enters the corresponding logic control layer. According to the preset adjustment logic in the logic control layer, the opening and closing states of the valves of the steam turbine in the thermal power unit corresponding to the logic control layer are adjusted respectively, so that the steam turbine enters the corresponding operating condition.

[0005] In conjunction with the first aspect, in one possible implementation, the logic control layer includes: a pure condensation layer, a heating layer, and a zero-output layer; According to the preset adjustment logic within the logic control layer, the opening and closing states of the valves in the steam turbine of the thermal power unit corresponding to the logic control layer are adjusted respectively, so that the steam turbine enters the corresponding operating condition, including: Each logic control layer includes regulation logic for different valves of the steam turbine. The opening and closing states of the valves corresponding to the logic control layer are adjusted according to the regulation logic. The steam energy delivery is controlled according to the opening and closing states of the valves, and the operating conditions of the steam turbine are adjusted.

[0006] In conjunction with the first aspect, in one possible implementation, the operating conditions correspond to the steam energy delivery conditions of the steam turbine of the thermal power unit. The operating conditions include: pure condensation condition, heating condition, and zero output condition; The pure condensation condition indicates that the steam energy of the turbine is used only to perform work from the intermediate pressure cylinder of the turbine to the low pressure cylinder of the turbine. The heating operation condition indicates that a portion of the steam energy of the steam turbine is used to perform work from the intermediate-pressure cylinder of the steam turbine to the low-pressure cylinder of the steam turbine, while the other portion of the steam energy is used to supply heat to the outside. The zero-output condition indicates that the steam energy of the turbine is used only for external heating.

[0007] In conjunction with the first aspect, in one possible implementation, the pure condensate layer includes control logic for a regulating valve for the medium- and low-pressure connecting pipe; wherein the regulating valve for the medium- and low-pressure connecting pipe is disposed in the medium- and low-pressure connecting pipe between the intermediate-pressure cylinder and the low-pressure cylinder of the steam turbine, and is used to control the conduction of the medium- and low-pressure connecting pipe by its own opening degree. The heating layer includes control logic for the regulating valve, extraction steam non-return valve, extraction steam regulating valve, and extraction steam shut-off valve of the medium- and low-pressure connecting pipe; wherein, the extraction steam non-return valve, the extraction steam regulating valve, and the extraction steam shut-off valve are installed in the heating extraction steam pipeline and are used to control the conduction of the heating extraction steam pipeline through a combination of open and closed states; the heating extraction steam pipeline is connected to the medium- and low-pressure connecting pipe and is used to transfer steam energy to the outside of the steam turbine for heating; The zero-output layer includes control logic for the medium- and low-pressure connecting pipe regulating valve, the extraction steam non-return valve, the extraction steam regulating valve, the extraction steam shut-off valve, the cooling steam regulating valve, and the water spray desuperheating regulating valve. The cooling steam regulating valve is located in the cooling steam pipeline and controls the flow of the cooling steam pipeline by its own opening degree. The water spray desuperheating regulating valve is located in the water spray desuperheating pipeline and controls the flow of the water spray desuperheating pipeline by its own opening degree. The cooling steam pipeline is connected to the low-pressure cylinder of the turbine and is used to input cooling steam into the low-pressure cylinder of the turbine to remove the heat from the blower. The water spray desuperheating pipeline is connected to the low-pressure cylinder of the turbine and is used to spray water into the low-pressure cylinder for cooling.

[0008] In conjunction with the first aspect, in one possible implementation, the step of entering the corresponding logic control layer based on the operating status and control commands of the thermal power unit includes: When the actual power output of the thermal power unit is not less than a preset first threshold, a heating layer activation command is received, and no heating layer exit condition is met, the unit enters the heating layer from the pure condensing layer. The heating layer exit conditions include: the actual power output of the thermal power unit is less than the first threshold; a heating layer exit command is received; there is an unopened valve among the extraction steam check valve, the extraction steam regulating valve, and the extraction steam shut-off valve; or the exhaust pressure of the intermediate pressure cylinder of the turbine is greater than a preset second threshold. If any of the conditions for exiting the heating layer are met, the heating layer will exit into the pure condensing layer. When the actual power output of the thermal power unit is not less than the first threshold, the unit has entered the heating operation mode, a zero-output layer activation command is received, the flow rate in the cooling steam pipeline is greater than a preset third threshold, the extraction steam check valve is at its maximum opening, the extraction steam shut-off valve is at its maximum opening, and the opening of the extraction steam regulating valve is greater than a preset fourth threshold, and no zero-output layer exit condition is met, the unit enters the zero-output layer from the heating layer. The zero-output layer exit conditions include: the exhaust pressure of the intermediate-pressure cylinder of the turbine is greater than a preset second threshold, a zero-output layer exit command is received, the temperature of the second and last stage blades of the turbine is greater than a preset fifth threshold, the temperature of the last stage blades of the turbine is greater than a preset sixth threshold, or any heating layer exit condition is met.

[0009] In conjunction with the first aspect, in one possible implementation, it further includes: controlling the medium and low pressure connecting pipe regulating valve to the maximum opening degree when exiting from the heating layer to the pure condensation layer; When entering the heating layer but not the zero-output layer, control the opening of the medium and low pressure connecting pipe regulating valve to be no less than the seventh threshold. When entering the zero-output layer, control the opening of the medium-low pressure connecting pipe regulating valve to be less than the seventh threshold.

[0010] In conjunction with the first aspect, in one possible implementation, it further includes: closing the extraction steam shut-off valve when any one of the extraction steam shut-off conditions is met; The conditions for shutting off the extraction steam shut-off valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0011] In conjunction with the first aspect, in one possible implementation, it further includes: the opening degree of the extraction steam regulating valve is determined according to the valve position of the medium-low pressure connecting pipe regulating valve, and when the valve position of the medium-low pressure connecting pipe regulating valve is greater than the ninth threshold, it is permissible to control the opening degree of the extraction steam regulating valve to be less than the fourth threshold. The extraction steam regulating valve is closed if any one of the conditions for shutting off the extraction steam regulating valve is met. The conditions for shutting off the extraction steam regulating valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0012] In conjunction with the first aspect, in one possible implementation, it further includes: closing the extraction steam check valve when any one of the extraction steam check valve shut-off conditions is met; The conditions for shutting off the extraction steam non-return valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0013] In conjunction with the first aspect, in one possible implementation, it further includes: when entering the zero-output layer, controlling the opening of the cooling steam regulating valve to be not less than the tenth threshold. When entering the zero-output layer, control the opening of the water spray de-cooling regulating valve to be no less than the eleventh threshold.

[0014] The beneficial effects of the embodiments disclosed herein include: This disclosure provides a method for controlling the heating supply of a steam turbine in a thermal power unit. The method includes: entering a corresponding logic control layer based on the operating status and control commands of the thermal power unit; and adjusting the opening and closing states of valves in the steam turbine of the thermal power unit corresponding to the logic control layer according to preset adjustment logic, thereby enabling the steam turbine to enter the corresponding operating condition. This control method, by controlling the flow of steam energy between the intermediate-pressure cylinder and the low-pressure cylinder of the thermal power unit, can regulate the power generation and heating supply of the low-pressure cylinder of the steam turbine, thereby achieving regulation of power generation and heating supply. Attached Figure Description

[0015] Figure 1 A schematic flowchart illustrating a method for controlling the heating supply of a steam turbine in a thermal power unit, provided in an embodiment of this disclosure; Figure 2 A schematic diagram illustrating the correspondence between the logic control layer and operating conditions provided in this embodiment of the disclosure; Figure 3 This is a schematic diagram of the steam energy transmission direction provided in an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the control of a pure condensation layer device provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the control of the heating layer equipment provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of the control of a zero-output layer device provided in an embodiment of this disclosure. Detailed Implementation

[0016] This disclosure provides a method for controlling the heating supply of a steam turbine in a thermal power unit. The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure. Furthermore, the embodiments and features described herein can be combined with each other unless otherwise specified.

[0017] This disclosure provides a method for controlling the heating supply of a steam turbine in a thermal power unit, such as... Figure 1As shown, it can be implemented as follows: S101. Based on the operating status and control commands of the thermal power unit, enter the corresponding logic control layer; S102. According to the preset adjustment logic in the logic control layer, adjust the opening and closing state of the valves of the steam turbine in the thermal power unit corresponding to the logic control layer, so that the steam turbine enters the corresponding operating condition.

[0018] In this embodiment of the disclosure, the executing entity may be the control system of the steam turbine of the thermal power unit. The control system can receive external instructions, monitor the operating status of the steam turbine, and output control signals to control the valves in the steam turbine, thereby realizing the control of the steam turbine operating conditions.

[0019] In the control system of a thermal power unit's steam turbine, multiple logic control layers can be set up for the turbine's control. Each logic control layer can be configured according to the operating conditions of the thermal power unit supplying heat to the outside world. Each logic control layer includes adjustment logic for controlling various devices in the thermal power unit's steam turbine, enabling the steam turbine to operate stably under the corresponding operating conditions.

[0020] The adjustment logic in each logic control layer targets different valves in the steam turbine. By adjusting the opening degree or valve position of these valves, the opening and closing state of the valves is controlled, thereby controlling the direction of the working fluid transport in the steam turbine of the thermal power unit and realizing the control of the steam turbine for heating and power generation in the thermal power unit.

[0021] It should be noted that the operating status of the thermal power unit may include data characterizing the operating state of the thermal power unit, such as the actual power generation; the control commands may be instructions received by the control system of the steam turbine of the thermal power unit to control the thermal power unit to enter different logic control layers.

[0022] Specifically, the control method provided in this disclosure can regulate the power generation and heat supply of the low-pressure cylinder by controlling the flow of steam energy between the intermediate-pressure cylinder and the low-pressure cylinder of the thermal power unit, thereby achieving regulation of power generation and heat supply.

[0023] In yet another embodiment provided in this disclosure, such as Figure 2 As shown, the logic control layer includes: a pure condensation layer, a heating layer, and a zero-output layer; The above step S102, "According to the preset adjustment logic within the logic control layer, adjust the opening and closing states of the valves in the steam turbine of the thermal power unit corresponding to the logic control layer, so that the steam turbine enters the corresponding operating condition," can be implemented as follows: Each logic control layer includes regulation logic for different valves of the steam turbine. The opening and closing states of the valves corresponding to the logic control layer are adjusted according to the regulation logic. The steam energy delivery is controlled according to the opening and closing states of the valves, and the operating conditions of the steam turbine are adjusted.

[0024] In this embodiment of the disclosure, the logic control layer may include: a pure condensation layer, a heating layer, and a zero-output layer; each logic control layer corresponds to different operating conditions. According to... Figure 2 It can be seen that each logic control layer corresponds to the control logic for each valve between the intermediate-pressure cylinder and the low-pressure cylinder under different operating conditions. When the turbine's state is detected to have reached the predetermined operating condition, the corresponding logic control layer can be entered according to the control command. The opening and closing states of the valves controlled by that logic control layer are adjusted according to the pre-set control logic to control the delivery of steam energy, so that the turbine enters the corresponding operating condition and operates stably.

[0025] In another embodiment provided in this disclosure, the operating conditions correspond to the steam energy transmission conditions of the steam turbine of the thermal power unit. The operating conditions include: pure condensation condition, heating condition, and zero output condition; The pure condensation condition indicates that the steam energy of the turbine is used only to perform work from the intermediate pressure cylinder of the turbine to the low pressure cylinder of the turbine. The heating operation condition indicates that a portion of the steam energy of the steam turbine is used to perform work from the intermediate-pressure cylinder of the steam turbine to the low-pressure cylinder of the steam turbine, while the other portion of the steam energy is used to supply heat to the outside. The zero-output condition indicates that the steam energy of the turbine is used only for external heating.

[0026] In this embodiment of the disclosure, the operating condition of the thermal power unit supplying heat to the outside world can correspond to the steam energy transmission situation of the steam turbine of the thermal power unit. That is, according to the proportion of steam energy allocated to power generation and heat supply, multiple operating conditions are divided.

[0027] like Figure 3 As shown, under pure condensing operation, all the steam energy output from the intermediate-pressure cylinder enters the low-pressure cylinder. The low-pressure cylinder alone drives the turbine blades to rotate, converting the steam energy into mechanical energy, which in turn drives the engine to generate electricity. In this condition, the steam energy is not used for external heating; it is entirely used for power generation. This operating condition is suitable for situations where the unit needs to operate at maximum power output during peak electricity demand periods.

[0028] like Figure 3As shown, under heating conditions, the steam energy output from the intermediate-pressure cylinder is proportionally distributed to the low-pressure cylinder and the heating network outside the turbine. A portion of the steam energy is input into the low-pressure cylinder for power generation, while the remaining steam energy is extracted to the outside of the turbine and supplied as heat through the heating network. This operating condition can be applied during the winter heating season when there is a certain demand for both electricity and heating.

[0029] like Figure 3 As shown, under zero-output conditions, all the steam energy output from the intermediate-pressure cylinder is used for heating in the external heating network of the turbine. It should be noted that in practical applications, a portion of the steam needs to be input as cooling steam into the low-pressure cylinder to remove heat from the blower and prevent damage to the low-pressure cylinder blades. This operating condition can be applied when there is a surplus of electricity in the power grid but a surge in heating demand.

[0030] In another embodiment provided in this disclosure, the pure condensate layer includes control logic for a regulating valve for a medium- and low-pressure connecting pipe; wherein, the regulating valve for the medium- and low-pressure connecting pipe is disposed in a medium- and low-pressure connecting pipe between the intermediate-pressure cylinder and the low-pressure cylinder of the steam turbine, and is used to control the conduction of the medium- and low-pressure connecting pipe by its own opening degree. The heating layer includes control logic for the regulating valve, extraction steam non-return valve, extraction steam regulating valve, and extraction steam shut-off valve of the medium- and low-pressure connecting pipe; wherein, the extraction steam non-return valve, the extraction steam regulating valve, and the extraction steam shut-off valve are installed in the heating extraction steam pipeline and are used to control the conduction of the heating extraction steam pipeline through a combination of open and closed states; the heating extraction steam pipeline is connected to the medium- and low-pressure connecting pipe and is used to transfer steam energy to the outside of the steam turbine for heating; The zero-output layer includes control logic for the medium- and low-pressure connecting pipe regulating valve, the extraction steam non-return valve, the extraction steam regulating valve, the extraction steam shut-off valve, the cooling steam regulating valve, and the water spray desuperheating regulating valve. The cooling steam regulating valve is located in the cooling steam pipeline and controls the flow of the cooling steam pipeline by its own opening degree. The water spray desuperheating regulating valve is located in the water spray desuperheating pipeline and controls the flow of the water spray desuperheating pipeline by its own opening degree. The cooling steam pipeline is connected to the low-pressure cylinder of the turbine and is used to input cooling steam into the low-pressure cylinder of the turbine to remove the heat from the blower. The water spray desuperheating pipeline is connected to the low-pressure cylinder of the turbine and is used to spray water into the low-pressure cylinder for cooling.

[0031] In this embodiment of the disclosure, such as Figure 4As shown, the pure condensation layer corresponds to the pure condensation operating condition. Under this condition, only the control logic for the regulating valve 4 of the medium-low pressure connecting pipe is included. In the pure condensation condition, the flow of the medium-low pressure connecting pipe 3 can be changed through the regulating valve 4. The medium-low pressure connecting pipe 3 is the steam transport channel between the medium-pressure cylinder 1 and the low-pressure cylinder 2. The regulating valve 4 of the medium-low pressure connecting pipe can control the steam flow rate within the medium-low pressure connecting pipe 3.

[0032] The heating layer corresponds to the heating conditions, such as... Figure 5 As shown, the control logic includes the control of the medium-low pressure connecting pipe regulating valve 4, the extraction steam non-return valve 6, the extraction steam regulating valve 7, and the extraction steam shut-off valve 8. Under heating conditions, the steam flow rate in the medium-low pressure connecting pipe 3 can be controlled by adjusting the medium-low pressure connecting pipe regulating valve 4, and the conduction status of the heating extraction steam pipeline 5 can be controlled by the linkage control of the extraction steam non-return valve 6, the extraction steam regulating valve 7, and the extraction steam shut-off valve 8. The heating extraction steam pipeline 5 is a branch of the medium-low pressure connecting pipe 3 leading to the heating network. Several valves are arranged on the heating extraction steam pipeline 5 in the order of extraction steam non-return valve 6, extraction steam regulating valve 7, and extraction steam shut-off valve 8. The extraction steam non-return valve 6 prevents the steam in the heating extraction steam pipeline 5 from flowing back to the turbine, acting as a one-way flow control. The extraction steam regulating valve 7 controls the steam flow rate in the heating extraction steam pipeline 5, changing the heat output to the heating network. The extraction steam shut-off valve 8 can be installed at the very end of the heating extraction steam pipeline 5, and can realize the full opening and full closing control of the heating extraction steam pipeline 5.

[0033] The zero-output layer corresponds to the zero-output working condition, such as... Figure 6 As shown, the control logic includes the regulating valve 4 for the medium and low pressure connecting pipe, the steam extraction check valve 6, the steam extraction regulating valve 7, the steam extraction shut-off valve 8, the cooling steam regulating valve 10, and the water spray desuperheating regulating valve 13. Under zero output conditions, the steam transmission between the medium pressure cylinder 1 and the low pressure cylinder 2 can be cut off, so that all the steam energy output by the medium pressure cylinder 1 is output to the heating extraction steam pipeline 5 to improve the heating capacity.

[0034] In practical applications, after the steam transmission between the low-pressure cylinder 2 and the intermediate-pressure cylinder 1 is cut off, the gas volume in the low-pressure cylinder 2 decreases, but a vacuum state cannot be achieved. Some gas and steam remain in the low-pressure cylinder 2. However, when the rotor of the low-pressure cylinder 2 rotates, the rotor blades still do work on these residual gases, pushing them to the outside of the cylinder. This process increases the gas energy, generating heat, but there is insufficient steam to carry away this heat; this heat is the blow-air heat. To reduce the impact of the blow-air heat on the turbine, multiple cooling pipelines can be installed for the low-pressure cylinder 2, such as cooling steam pipeline 9 and water spray desuperheating pipeline 12. Cooling steam pipeline 9 can be a branch from the intermediate-low pressure connecting pipe 3, providing a small flow of steam to the low-pressure cylinder 2 to remove the blow-air heat. Water spray desuperheating pipeline 12 can be a pipeline connected to the spray system inside the low-pressure cylinder 2, providing desuperheating water to the spray system to absorb heat from the low-pressure cylinder. Cooling steam flow meter 11 and spray water flow meter 14 can be installed on cooling steam pipe 9 and spray water desuperheating pipe 12 respectively to monitor the flow rate of cooling steam and spray water, and adjust cooling steam regulating valve 10 and spray water desuperheating regulating valve 13 based on this to control the amount of cooling steam and spray water input to low-pressure cylinder 2, so as to achieve better heat dissipation effect.

[0035] In another embodiment provided in this disclosure, the step S101 above, "entering the corresponding logic control layer according to the operating status and control commands of the thermal power unit," can be implemented as follows: Step 1: When the actual power output of the thermal power unit is not less than a preset first threshold, a heating layer activation command is received, and no heating layer exit condition is met, the unit enters the heating layer from the pure condensing layer. The heating layer exit conditions include: the actual power output of the thermal power unit is less than the first threshold; a heating layer exit command is received; there is an unopened valve among the extraction steam check valve 6, the extraction steam regulating valve 7, and the extraction steam shut-off valve 8; or the exhaust pressure of the intermediate pressure cylinder 1 of the turbine is greater than a preset second threshold. Step 2: If any of the conditions for exiting the heating layer are met, the heating layer will exit into the pure condensation layer. Step 3: When the actual power output of the thermal power unit is not less than the first threshold, the unit has entered the heating operation mode, a zero-output layer activation command is received, the flow rate in the cooling steam pipeline 9 is greater than the preset third threshold, the extraction steam check valve 6 is at its maximum opening, the extraction steam shut-off valve 8 is at its maximum opening, and the opening of the extraction steam regulating valve 7 is greater than the preset fourth threshold, and no zero-output layer exit condition is met, the unit enters the zero-output layer from the heating layer. The zero-output layer exit conditions include: the exhaust pressure of the intermediate pressure cylinder 1 of the turbine is greater than the preset second threshold, a zero-output layer exit command is received, the temperature of the second and last stage blades of the turbine is greater than the preset fifth threshold, the temperature of the last stage blades of the turbine is greater than the preset sixth threshold, or any heating layer exit condition is met.

[0036] In this embodiment of the disclosure, the logic control layer of the thermal power unit can start from the pure condensing layer. When the actual power generation of the thermal power unit reaches a certain first threshold and there is no heating layer exit condition, it can enter the heating layer from the pure condensing layer according to the heating layer entry command. The first threshold can be the minimum power that can meet the power demand of the power grid. When the heating layer exit condition is triggered, it can exit from the heating layer to the pure condensing layer.

[0037] The exit conditions for the heating layer can include multiple judgment criteria. When any of these criteria is met, the heating layer can exit to the pure condensing layer to maintain a stable output of electrical energy from the thermal power unit. For example, if the actual power generation of the thermal power unit is less than the first threshold, it indicates that the current thermal power unit turbine operating in heating mode cannot meet the power demand of the grid. The logic control layer needs to exit to the pure condensing layer so that the thermal power unit turbine operates in pure condensing mode to meet the grid's demand. If any of the extraction steam check valve 6, extraction steam regulating valve 7, or extraction steam shut-off valve 8 is not open, it indicates that the steam energy of the intermediate-pressure cylinder 1 cannot be normally output to the heating pipeline. It needs to return to the pure condensing layer to prevent the pressure of the intermediate-pressure cylinder 1 from increasing and exceeding the second threshold, thus ensuring the safe operation of the turbine. The second threshold can be the maximum permissible safe pressure critical value for the intermediate-pressure cylinder 1.

[0038] After entering the heating layer, if the actual power generation of the thermal power unit can stably meet the grid demand, the steam flow rate supplied to the cooling steam pipe 9 is greater than the third threshold, the steam output to the heating pipe meets the preset steam quantity, the zero-output layer exit condition is not triggered, and a zero-output layer activation command is received, then the unit can enter the zero-output layer from the heating layer, and the low-pressure cylinder 2 of the turbine will not generate electricity. The steam output from the intermediate-pressure cylinder 1 enters the cooling steam pipe 9 and the heating extraction steam pipe 5 respectively, providing cooling for the low-pressure cylinder 2 and heating for the heating pipe. The third threshold can be the minimum steam flow rate required to cool the low-pressure cylinder 2, and the fourth threshold can be the minimum opening of the extraction steam regulating valve 7 to ensure the heating capacity of the heating system.

[0039] The exit conditions for the zero-output layer can include multiple judgment criteria. When any one of these criteria is met, the system can exit from the zero-output layer and exit into the heating layer. Examples include: the exhaust pressure of intermediate-pressure cylinder 1 exceeding the second threshold; the temperature of the second and last stage blades of the turbine exceeding the pre-set fifth threshold; and the temperature of the last stage blades of the turbine exceeding the pre-set sixth threshold. A temperature exceeding the fifth or sixth threshold indicates that the cooling steam cannot provide sufficient cooling capacity; the fifth and sixth thresholds are the maximum safe temperature critical values ​​for the second and last stage blades, respectively.

[0040] Furthermore, the exit conditions for both the zero-output layer and the heating layer can also include triggering conditions such as cylinder tripping, turbine over-speed protection control (OPC), and generator tripping. When these conditions occur, the system exits to the previous logic control layer, ensuring the safe and stable operation of the generator set.

[0041] In another embodiment provided in this disclosure, it further includes: when exiting from the heating layer to the pure condensation layer, controlling the medium and low pressure connecting pipe regulating valve 4 to be at its maximum opening; When entering the heating layer but not the zero-output layer, control the opening of the medium and low pressure connecting pipe regulating valve 4 to be no less than the seventh threshold. When entering the zero-output layer, control the opening of the medium-low pressure connecting pipe regulating valve 4 to be less than the seventh threshold.

[0042] In this embodiment of the disclosure, different control logics are applied to different valves in different logic control layers. When the system exits from the heating layer to the pure condensation layer, that is, from the heating condition to the pure condensation condition, the opening degree of the regulating valve 4 of the medium-low pressure connecting pipe between the medium-pressure cylinder 1 and the low-pressure cylinder 2 is controlled to the maximum opening degree, so that all the steam energy of the medium-pressure cylinder 1 is output to the low-pressure cylinder.

[0043] In the heating layer (i.e., under heating conditions), the opening degree of the regulating valve 4 of the low-pressure connecting pipe is not less than the seventh threshold, where the seventh threshold can be the minimum opening degree that ensures the low-pressure cylinder 2 can output electrical energy and heat energy. By adjusting the opening degree between the seventh threshold and the maximum opening degree, the ratio of power generation and heat supply can be adjusted according to the power supply and heat supply requirements of the power grid.

[0044] In the zero-output layer (i.e., under zero-output operating conditions), the opening degree of the medium-low pressure connecting pipe regulating valve 4 is controlled to be less than the seventh threshold, so that the steam energy output from the medium-pressure cylinder 1 to the low-pressure cylinder 2 does not perform work in the low-pressure cylinder 2. Furthermore, the opening degree of the medium-low pressure connecting pipe regulating valve 4 can be adjusted to the closed state, so that all the steam energy is output to the heating pipeline, achieving maximum heating capacity and reducing power generation.

[0045] In another embodiment provided in this disclosure, the method further includes: closing the extraction steam shut-off valve 8 when any one of the shut-off conditions of the extraction steam shut-off valve 8 is met; The conditions for shutting off the extraction steam shut-off valve 8 include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0046] In this embodiment of the present disclosure, the extraction steam shut-off valve 8 serves as a valve that controls the connection between the steam turbine and the heating pipeline. According to the preset shut-off conditions, when one of these shut-off conditions is triggered, the extraction steam shut-off valve 8 can be shut off to isolate the transmission of steam between the steam turbine and the heating pipeline, thereby protecting the stable and safe operation of the system.

[0047] The eighth threshold can be the lower limit of the power supply demand of the power grid. Reaching this value indicates that the generator set needs to use all of its steam energy for power generation in order to meet the power grid's demand.

[0048] In another embodiment provided in this disclosure, the opening degree of the extraction steam regulating valve 7 is determined according to the valve position of the medium and low pressure connecting pipe regulating valve 4. When the valve position of the medium and low pressure connecting pipe regulating valve 4 is greater than the ninth threshold, the opening degree of the extraction steam regulating valve 7 is allowed to be less than the fourth threshold. If any of the conditions for shutting off the extraction steam regulating valve 7 are met, the extraction steam regulating valve 7 shall be closed. The conditions for shutting off the extraction steam regulating valve 7 include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0049] In this embodiment, there is a mutual constraint relationship between the opening degree of the extraction steam regulating valve 7 and the valve position of the medium-low pressure connecting pipe regulating valve 4. Only when the valve position of the medium-low pressure connecting pipe regulating valve 4 is greater than the ninth threshold can the opening degree of the extraction steam regulating valve 7 be adjusted to be less than the fourth threshold. This method ensures that there is at least a certain output channel for steam energy, preventing the pressure of the medium-pressure cylinder 1 from abnormally rising above a safe value due to the inability to output steam.

[0050] In another embodiment provided in this disclosure, the method further includes: closing the extraction steam non-return valve 6 when any one of the conditions for closing the extraction steam non-return valve 6 is met; The conditions for shutting off the extraction steam non-return valve 6 include: the actual power generation of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

[0051] In this embodiment, the extraction steam non-return valve 6 serves as a valve controlling the connection between the heating extraction steam pipeline 5 and the steam turbine. According to pre-set shut-off conditions, when one of these shut-off conditions is triggered, the extraction steam non-return valve 6 can be shut off to isolate the steam transmission between the steam turbine and the heating extraction steam pipeline 5, thereby protecting the stable and safe operation of the system.

[0052] In another embodiment provided in this disclosure, it further includes: when entering the zero-output layer, controlling the opening degree of the cooling steam regulating valve 10 to be not less than the tenth threshold. When entering the zero-output layer, control the opening of the water spray de-heating regulating valve 13 to be no less than the eleventh threshold.

[0053] In this embodiment of the disclosure, the tenth threshold is the minimum opening degree of the cooling steam regulating valve 10 that ensures sufficient cooling steam output to the low-pressure cylinder 2. The eleventh threshold is the minimum opening degree of the cooling steam regulating valve 10 that ensures sufficient spray water output to the low-pressure cylinder 2.

[0054] This document provides a possible implementation to illustrate the configuration and control flow of the logic control layer for the steam turbine. The thermal power unit used here has a rated power of [missing information]. Taking a supercritical single-shaft four-cylinder four-exhaust condensing steam turbine unit with single-stage intermediate reheat as an example, the following conditions can be set for the heating layer to enter the logic: 1) Actual generating power of the unit ; 2) Received instruction to activate the heating layer; 3) No conditions for the removal of the heating layer.

[0055] The following conditions can be set as conditions for the heating layer to be deactivated: 1) Actual generating power of the unit ; 2) Received a command to exit the heating supply layer; 3) Of the three valves—extraction steam check valve 6, extraction steam regulating valve 7, and extraction steam shut-off valve 8—one is fully closed and not open. 4) The exhaust pressure of intermediate pressure cylinder 1 is high and not an abnormal value. ; 5) Turbine tripping; 6) OPC actions; 7) Generator tripped.

[0056] The logic for entering a zero-output layer can be set to require the following conditions to be met simultaneously: 1) Actual generating power of the unit ; 2) The heating layer is already in operation; 3) Received the command to engage the zero-output layer; 4) Total cooling steam flow rate ; 5) When extraction steam shut-off valve 8 is fully open, extraction steam check valve 6 is fully open, and extraction steam regulating valve 7 is open to [specific degree]. ; 6) There is no zero-output layer exit condition.

[0057] The exit condition for the zero-output layer can be set to satisfy any of the following conditions: 1) Turbine tripped; 2) OPC actions; 3) Generator tripped.

[0058] 4) The exhaust pressure of intermediate pressure cylinder 1 is high and not an abnormal value. .

[0059] 5) Heating layer removed; 6) Received a zero-output layer exit command; 7) The temperature of the second-to-last stage blades is high. ; 8) High temperature in the last stage, high temperature in the last stage blades .

[0060] Furthermore, the control logic for the medium- and low-pressure connecting pipe regulating valve 4 can be configured as follows: OPC, turbine trip, or turbine overspeed At this time, the regulating valve 4 of the medium and low pressure connecting pipe can be fully opened to .

[0061] When the cylinder exhaust pressure At that time, the regulating valve 4 of the medium and low pressure connecting pipe can be fully opened to .

[0062] In the event of a heating layer disconnection, the regulating valve 4 of the medium and low pressure connecting pipe can be fully opened to... Meanwhile, the valve position command is tracked to .

[0063] When the heating layer is in operation and the zero-output layer is not in operation, the minimum opening of the regulating valve 4 of the medium and low pressure connecting pipe is as follows: .

[0064] After the zero-output layer is put into operation, the opening degree of the regulating valve 4 of the medium and low pressure connecting pipe can be adjusted to... the following.

[0065] The extraction steam shut-off valve 8 can be interlocked and closed if any of the following conditions are met: 1) Actual power generation of thermal power units ; 2) Turbine tripping; 3) OPC actions; 4) Generator tripped.

[0066] The control logic for extraction steam regulating valve 7 can be set as follows: When the valve position of the low-pressure connecting pipe regulating valve 4 is... In this case, the extraction steam regulating valve 7 can be closed to below 30%.

[0067] Steam extraction regulating valve 7 can be interlocked closed under any of the following conditions: 1) Actual generating power of the unit .

[0068] 2) Turbine tripping; 3) OPC actions; 4) Generator tripped.

[0069] The control logic for steam extraction check valve 6 can be set as follows: The extraction steam check valve 6 can be interlocked closed under any of the following conditions: 1) Actual generating power of the unit ; 2) Turbine tripping; 3) OPC actions; 4) Generator tripped.

[0070] The control logic for the cooling steam regulating valve 10 is set as follows: When the zero-output layer is activated, the minimum opening degree of the cooling steam regulating valve 10 is... .

[0071] The control logic for the water spray desuperheating regulating valve 13 is set as follows: When the zero-output layer is activated, the minimum opening of the water spray desuperheating regulating valve 13 is... .

[0072] The alarm signal triggering conditions for the zero-output layer are set as follows: Alarm pressure of intermediate pressure cylinder exhaust ; Alarm temperature of intermediate pressure cylinder exhaust ; Alarm temperature of the second and final stage blades ; High alarm temperature of the last stage blades ; Exhaust alarm temperature .

[0073] During the commissioning test of the aforementioned thermal power unit, the original low-pressure cylinder steam was switched to the first station of the heating network for heating, achieving zero output from the low-pressure cylinder and reducing the unit's electrical output. This setup stabilizes the unit's operating parameters, allowing for smooth and stable switching between the pure condensing, heating, and zero-output modes. During commissioning in zero-output mode, with the main steam flow remaining essentially constant, the unit's power generation decreases while the heating extraction steam flow increases. Conversely, during decommissioning from zero-output mode, the unit's power generation increases while the heating extraction steam flow decreases. Throughout the commissioning and decommissioning processes, all parameters in the unit's operation and monitoring sections remain stable.

[0074] After adopting the control method provided in this disclosure, the heating extraction steam flow rate is as follows during the turbine heat consumption acceptance test: The equivalent heating load is Power generation capacity is Coal consumption for power generation is approximately ,according to According to heating capacity calculations, a single unit can provide heating to an annual external heating area of ​​9.88 million square meters. Compared to existing control methods, this approach can provide higher heating loads and reduce power generation.

[0075] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments of this disclosure can be implemented in hardware or by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0076] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes in the drawings are not necessarily essential for implementing this disclosure.

[0077] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0078] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0079] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A method for controlling the heating supply of a steam turbine in a thermal power unit, characterized in that, include: Based on the operating status and control commands of the thermal power unit, the system enters the corresponding logic control layer. According to the preset adjustment logic in the logic control layer, the opening and closing states of the valves of the steam turbine in the thermal power unit corresponding to the logic control layer are adjusted respectively, so that the steam turbine enters the corresponding operating condition.

2. The method as described in claim 1, characterized in that, The logic control layer includes: a pure condensation layer, a heating layer, and a zero-output layer; According to the preset adjustment logic within the logic control layer, the opening and closing states of the valves in the steam turbine of the thermal power unit corresponding to the logic control layer are adjusted respectively, so that the steam turbine enters the corresponding operating condition, including: Each logic control layer includes regulation logic for different valves of the steam turbine. The opening and closing states of the valves corresponding to the logic control layer are adjusted according to the regulation logic. The steam energy delivery is controlled according to the opening and closing states of the valves, and the operating conditions of the steam turbine are adjusted.

3. The method as described in claim 1 or 2, characterized in that, The operating conditions correspond to the steam energy transmission conditions of the steam turbine of the thermal power unit, respectively; The operating conditions include: pure condensation condition, heating condition, and zero output condition; The pure condensation condition indicates that the steam energy of the turbine is used only to perform work from the intermediate pressure cylinder of the turbine to the low pressure cylinder of the turbine. The heating operation condition indicates that a portion of the steam energy of the steam turbine is used to perform work from the intermediate-pressure cylinder of the steam turbine to the low-pressure cylinder of the steam turbine, while the other portion of the steam energy is used to supply heat to the outside. The zero-output condition indicates that the steam energy of the turbine is used only for external heating.

4. The method as described in claim 2, characterized in that, The pure condensation layer includes control logic for the regulating valve of the medium and low pressure connecting pipe; wherein, the regulating valve of the medium and low pressure connecting pipe is installed in the medium and low pressure connecting pipe between the intermediate pressure cylinder and the low pressure cylinder of the steam turbine, and is used to control the conduction of the medium and low pressure connecting pipe by its own opening degree. The heating layer includes control logic for the regulating valve, extraction steam non-return valve, extraction steam regulating valve, and extraction steam shut-off valve of the medium- and low-pressure connecting pipe; wherein, the extraction steam non-return valve, the extraction steam regulating valve, and the extraction steam shut-off valve are installed in the heating extraction steam pipeline and are used to control the conduction of the heating extraction steam pipeline through a combination of open and closed states; the heating extraction steam pipeline is connected to the medium- and low-pressure connecting pipe and is used to transfer steam energy to the outside of the steam turbine for heating; The zero-output layer includes control logic for the medium- and low-pressure connecting pipe regulating valve, the extraction steam non-return valve, the extraction steam regulating valve, the extraction steam shut-off valve, the cooling steam regulating valve, and the water spray desuperheating regulating valve. The cooling steam regulating valve is located in the cooling steam pipeline and controls the flow of the cooling steam pipeline by its own opening degree. The water spray desuperheating regulating valve is located in the water spray desuperheating pipeline and controls the flow of the water spray desuperheating pipeline by its own opening degree. The cooling steam pipeline is connected to the low-pressure cylinder of the turbine and is used to input cooling steam into the low-pressure cylinder of the turbine to remove the heat from the blower. The water spray desuperheating pipeline is connected to the low-pressure cylinder of the turbine and is used to spray water into the low-pressure cylinder for cooling.

5. The method as described in claim 4, characterized in that, The process of entering the corresponding logic control layer based on the operating status and control commands of the thermal power unit includes: When the actual power output of the thermal power unit is not less than a preset first threshold, a heating layer activation command is received, and no heating layer exit condition is met, the unit enters the heating layer from the pure condensing layer. The heating layer exit conditions include: the actual power output of the thermal power unit is less than the first threshold; a heating layer exit command is received; there is an unopened valve among the extraction steam check valve, the extraction steam regulating valve, and the extraction steam shut-off valve; or the exhaust pressure of the intermediate pressure cylinder of the turbine is greater than a preset second threshold. If any of the conditions for exiting the heating layer are met, the heating layer will exit into the pure condensing layer. When the actual power output of the thermal power unit is not less than the first threshold, the unit has entered the heating operation mode, a zero-output layer activation command is received, the flow rate in the cooling steam pipeline is greater than a preset third threshold, the extraction steam check valve is at its maximum opening, the extraction steam shut-off valve is at its maximum opening, and the opening of the extraction steam regulating valve is greater than a preset fourth threshold, and no zero-output layer exit condition is met, the unit enters the zero-output layer from the heating layer. The zero-output layer exit conditions include: the exhaust pressure of the intermediate-pressure cylinder of the turbine is greater than a preset second threshold, a zero-output layer exit command is received, the temperature of the second and last stage blades of the turbine is greater than a preset fifth threshold, the temperature of the last stage blades of the turbine is greater than a preset sixth threshold, or any heating layer exit condition is met.

6. The method as described in claim 5, characterized in that, Also includes: When exiting from the heating layer to the pure condensation layer, the regulating valve of the medium and low pressure connecting pipe is controlled to be at its maximum opening. When entering the heating layer but not the zero-output layer, control the opening of the medium and low pressure connecting pipe regulating valve to be no less than the seventh threshold. When entering the zero-output layer, control the opening of the medium-low pressure connecting pipe regulating valve to be less than the seventh threshold.

7. The method as described in claim 5, characterized in that, Also includes: Close the extraction steam shut-off valve if any of the extraction steam shut-off conditions are met. The conditions for shutting off the extraction steam shut-off valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

8. The method as described in claim 5, characterized in that, Also includes: The opening degree of the extraction steam regulating valve is determined according to the valve position of the medium and low pressure connecting pipe regulating valve. When the valve position of the medium and low pressure connecting pipe regulating valve is greater than the ninth threshold, the opening degree of the extraction steam regulating valve is allowed to be less than the fourth threshold. The extraction steam regulating valve is closed if any one of the conditions for shutting off the extraction steam regulating valve is met. The conditions for shutting off the extraction steam regulating valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

9. The method as described in claim 5, characterized in that, Also includes: Close the extraction steam check valve if any one of the extraction steam check valve shut-off conditions is met. The conditions for shutting off the extraction steam non-return valve include: the actual power output of the thermal power unit is less than the eighth threshold, the turbine triggers overspeed protection, the turbine trips, and the thermal power unit trips.

10. The method as described in claim 5, characterized in that, Also includes: When entering the zero-output layer, the opening of the cooling steam regulating valve is controlled to be no less than the tenth threshold. When entering the zero-output layer, control the opening of the water spray de-cooling regulating valve to be no less than the eleventh threshold.

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