Automatic control method and system for two machines and one tower of circulating water system of thermal power generating unit

Abstract

The invention discloses an automatic control method and system for one tower on two machines of a thermal power generating unit circulating water system. When the running frequencies and outlet pressures of the circulating water pumps of the two units are adjusted to be consistent, a communication valve of the circulating water systems of the two units is opened, so that the circulating water systems of the two units enter parallel operation; after the pressure of the system is stable and the liquid levels of the expansion water tanks of the two indirect cooling towers are consistent, all sectors of the indirect cooling towers to quit operation are cut off in sequence; according to the back pressure of the two units, the operation frequency of circulating pumps of the two units and the opening degree of shutters in operation of indirect cooling sectors are adjusted, meanwhile, the liquid level changes of expansion water tanks of the two indirect cooling towers are considered, and the back pressure of the units is kept stable. Economical operation of the unit is achieved, and meanwhile the risk of freezing of cold sectors between single units possibly caused by insufficient steam exhaust heat during low-load operation under the working condition in winter is avoided. And safe and stable operation of the cold circulating water system between the two units is effectively guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic control of circulating water systems of thermal power units, and in particular relates to an automatic control method and system for a tower on two machines of a circulating water system of a thermal power unit. Background Art

[0002] In recent years, based on the industry's requirements for coal consumption and heating of coal-fired generating units, more and more power plants have gradually introduced cylinder cutting technology or low-pressure cylinder zero output technology, and only retain the minimum cooling flow of the low-pressure cylinder. In order to ensure the requirements of heating steam flow, some units even implement back pressure machine heating and completely cut off the low-pressure cylinder operation. Indirect air cooling has been widely used in thermal power units in water-scarce areas in recent years due to its advantages such as saving water resources, low power consumption, low cost and low noise. The indirect air cooling system can use circulating water to cool the exhaust steam of the steam turbine, and allow the heated circulating water to enter the natural ventilation cooling tower, and use the air in it to achieve cooling and cooling. At the same time, it can also maintain the heat in the intercooling tower in winter, ensure the heat load of the intercooling sector, and reduce the risk of freezing during sector operation.

[0003] Generally, two units are equipped with two natural ventilation indirect air cooling towers, arranged as one unit and one tower. The main engine indirect air cooling system adopts an expanded unit system recirculating water supply system. Each unit is equipped with three main engine circulating water pumps with 35% capacity and matching frequency conversion devices, one natural ventilation intercooling tower, one set of main engine circulating water supply and return water pipelines, expansion water tanks, underground water storage tanks, filling pumps, water supply pumps, etc. The air required for heat exchange in the indirect air cooling system is provided by the air supply system, and a natural ventilation hyperbolic tower is adopted. The cooling tower is divided into 12 cooling sectors, each sector contains several cooling triangles. The cooling triangles are arranged vertically along the circumference of the cooling tower. Each sector is equipped with an inlet valve, an outlet valve and two drain valves. By operating these valves, water filling and draining operations can be performed on each sector separately. If the water inlet valve and the water outlet valve are in the open position and the drain valve is in the closed position, the sector is in a water-filled state. The water-filled state is the normal operating mode of the cooling triangle. In this state, the circulating cooling water flows through the cooling triangle radiators arranged in parallel to exchange heat with the air.

[0004] Both units are designed with a cylinder cutting function. Considering the intercooling antifreeze problem under cylinder cutting conditions, the main engine circulating water systems of the two units are equipped with communication pipes, which can realize two units on one tower in winter heating conditions and two towers on one unit in summer conditions, improving the operating flexibility and economy of the main engine circulating water system. The application of this technology reduces the coal consumption of the unit, but for the indirect air-cooled unit, after the turbine is heated to the outside or the cylinder is cut, the heat load of the low-pressure cylinder will be greatly reduced, and the circulating water temperature will also decrease accordingly. Especially during winter operation, due to the significant reduction in exhaust steam heat, the heat carried away by the circulating water is far from sufficient, and the risk of freezing during the operation of the intercooling sector increases sharply, and conventional antifreeze measures are ineffective. It brings huge risks to the safety of unit operation. Summary of the invention

[0005] The object of the present invention is to provide an automatic control method and system for one tower on two machines of a circulating water system of a thermal power unit to solve the above-mentioned problem.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The automatic control method of a two-unit-on-one-tower circulating water system of a thermal power unit includes: Obtain the start / stop status and load of the first unit, as well as the start / stop status and load of the second unit; obtain the operating status and parameters of the three circulating water pumps of the first unit and the three circulating water pumps of the second unit in the circulating water system of the two intercooling units; obtain the intercooling sector switching status of the first unit and the intercooling sector switching status of the second unit; When the operating frequency and outlet pressure of the circulating water pumps of the two units are adjusted to be consistent, the communication valves of the circulating water systems of the two units are opened to make the circulating water systems of the two units run in parallel; After the system pressure is stable and the liquid levels of the expansion water tanks of the two intercooling towers are consistent, cut off the sectors of the intercooling towers to be shut down in turn, that is, close the inlet and return valves of the sectors of the intercooling tower of the first unit or the inlet and return valves of the sectors of the intercooling tower of the second unit; According to the back pressure of the two units, adjust the operating frequency of the circulation pumps of the two units and the shutter opening of the intercooler sector put into operation, while taking into account the changes in the liquid level of the two intercooler tower expansion tanks to maintain the back pressure of the units stable. Make the back pressure deviation of the two units not exceed 5kpa, and the maximum upper limit does not exceed 15kpa, otherwise the cut-off intercooler tower sector will be put into operation.

[0007] Furthermore, the loads of the two units are both lower than 30% of the rated load, and the ambient temperature is lower than 20°C; the three circulating water pumps of the first unit are in operation, and the three circulating water pumps of the second unit are in operation; the valves include the inlet and outlet valves of the circulating water pump of the first unit, the inlet and outlet valves of the circulating water pump of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems are ready for parallel operation, including: Stop one circulating water pump of the first unit; stop one circulating water pump of the second unit; reduce the flow of the circulating water systems of the two units and enter parallel operation.

[0008] Further, the circulating water system of the first unit is in a two-pump operation state; the circulating water system of the second unit is in a two-pump operation state; the valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the communication valves of the circulating water systems of the two units, so that the circulating water systems enter a state ready for parallel operation, including: Reduce the frequency of all running circulating water pumps of the two units, and maintain the stability of back pressure through the shutters of each sector until the frequency of the four circulating water pumps drops to the minimum operating frequency and maintains the same outlet pressure.

[0009] Further, when the operating parameters of the four circulating water pumps of the two units are detected to be consistent and the states of the valves are correct, the circulating water cooling and hot water communication valves of the two units are prepared to be opened, including: By detecting the operating parameters of the two circulating water pumps of the first unit and whether the corresponding outlet doors and inlet doors are both in a fully open state, it is determined that the number of intercooling sectors in the first unit is greater than 1; By detecting the operating parameters of the two circulating water pumps of the second unit and whether the corresponding outlet doors and inlet doors are both in a fully open state, it is determined that the number of intercooling sectors in the second unit is greater than 1; By detecting whether the outlet door and the inlet door of the circulating water pump of the first unit are both in the fully open state, and detecting the pressure of the circulating water system of the first unit, after the preset time period of frequency adjustment, whether the deviation between the outlet main pipe pressure of the circulating water pump of the first unit and the pressure of the circulating water main pipe of the second unit is less than a preset threshold, it is judged whether the circulating water pump of the first unit meets the conditions for parallel pumping; By detecting whether the outlet door and the inlet door of the circulating water pump of the second unit are both in the fully open state, and detecting the circulating water system pressure of the second unit, after the frequency adjustment preset time period, whether the deviation between the outlet main pipe pressure of the circulating water pump of the second unit and the circulating water main pipe pressure of the first unit is less than a preset threshold, it is judged whether the circulating water pump of the second unit meets the pumping conditions; If it is determined that the deviation between the circulating water main pipe pressure of the first unit and the circulating water main pipe pressure of the second unit is less than the preset threshold, the cold and hot water connecting valves of the circulating water systems of the two units are controlled to open to realize parallel operation of the circulating water systems of the two units.

[0010] Furthermore, the cold and hot water pipe connecting valves include a first cold water pipe connecting valve and a second cold water pipe connecting valve, and a first hot water pipe connecting valve and a second hot water pipe connecting valve respectively; when opening the connecting valves of the circulating water systems of the two units, first open the first cold water pipe connecting valve to 10%, check that the cold water main pipe pressure, temperature and other parameters have not changed, and confirm that the second cold water pipe connecting valve is tightly closed; then open the first hot water pipe connecting valve to 10%, check that the hot water main pipe pressure, temperature and other parameters have not changed, and confirm that the second hot water pipe connecting valve is tightly closed; then open the second cold water pipe connecting valve to 5% opening, observe the changes in the cold water main pipe parameters and the liquid level fluctuations of the two intercooler expansion water tanks, if the water level has not changed, continue to open the second cold water pipe connecting valve to 10%, continue to observe and repeat the operation until the second cold water pipe connecting valve is fully opened; finally, open the second hot water pipe connecting valve to 5%, observe the system parameters, and continue to open it to 10% if there is no abnormality, repeat the operation until all are opened, and the circulating water systems of the two units are connected in parallel.

[0011] Furthermore, during the opening of the circulating water cooling and hot water connecting valves of the two units, if the detected liquid level continues to drop to a lower value, the underground water tank replenishment pump is started to continuously replenish water to stabilize the liquid level in the expansion tank.

[0012] Further, by adjusting the frequencies of the circulating water pumps of the two units to operate differentially, the pressure deviation can be corrected and the pressure of the circulating water pipe can be made consistent.

[0013] Further, the i-th sector of the intercooling tower includes the i-th sector of the intercooling tower of the first unit and the i-th sector of the intercooling tower of the second unit, the shutter opening includes the shutter opening of the first unit sector and the shutter opening of the second unit, and the back pressure includes the back pressure of the first unit and the back pressure of the second unit; After the circulating water systems of the two units are in parallel and running stably, start to cut off the intercooler to be withdrawn, that is, close the sector inlet and return valves of the intercooler of the first unit or the intercooler of the second unit; Control the inlet and return valves of the i-th sector of the intercooler to close at the same time. After exiting, monitor that the circulating water pressure of the unit is stable and the back pressure of the unit does not change. Open the drain valves of the inlet and return pipes of the i-th sector of the intercooler until all sectors are exited. Observe that the back pressure of the two units is normal and operates within the allowable range.

[0014] Furthermore, as the sector is withdrawn, the back pressure of the unit will increase. The shutter opening of the intercooler on the switching side will be opened wide, the circulating water temperature will be adjusted, the back pressure change will be controlled, the frequency of the circulating water pump of the intercooler on the cut-off side will be increased, the operating flow rate and flow velocity of the circulating water will be adjusted, and the back pressure will be regulated.

[0015] The automatic control system of the two-unit-on-one tower of the thermal power unit circulating water system includes: The data acquisition module is used to obtain the start / stop status and load of the first unit, as well as the start / stop status and load of the second unit; obtain the operating status and parameters of the three circulating water pumps of the first unit and the three circulating water pumps of the second unit in the circulating water system of the two intercooling units; obtain the switching status of the intercooling sectors of the first unit and the switching status of the intercooling sectors of the second unit; The regulating module is used to adjust the operating frequency and outlet pressure of the circulating water pumps of the two units to be consistent, and open the communication valves of the circulating water systems of the two units to make the circulating water systems of the two units run in parallel; The cut-off module is used to sequentially cut off the sectors of the intercooler to be withdrawn from operation after the system pressure is stable and the liquid levels of the expansion water tanks of the two intercoolers are consistent, that is, close the inlet and return valves of the sectors of the intercooler of the first unit or the inlet and return valves of the sectors of the intercooler of the second unit; The regulating module is used to adjust the operating frequency of the circulation pumps of the two units and the shutter opening of the intercooling sector put into operation according to the back pressure of the two units, while taking into account the changes in the liquid level of the two intercooling tower expansion tanks to maintain the stability of the unit back pressure, so that the back pressure deviation of the two units does not exceed 5kpa, and the maximum upper limit does not exceed 15kpa, otherwise the cut-off intercooling tower sector will be put into operation.

[0016] Furthermore, the loads of the two units are both lower than 30% of the rated load, and the ambient temperature is lower than 20°C; the three circulating water pumps of the first unit are in operation, and the three circulating water pumps of the second unit are in operation; the valves include the inlet and outlet valves of the circulating water pump of the first unit, the inlet and outlet valves of the circulating water pump of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems are ready for parallel operation, including: Stop one circulating water pump of the first unit; stop one circulating water pump of the second unit; reduce the flow of the circulating water systems of the two units and enter a parallel operation state; The circulating water system of the first unit is in a state where two pumps are running; the circulating water system of the second unit is in a state where two pumps are running; the valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems enter a state ready for parallel operation, including: Reduce the frequency of all running circulating water pumps of the two units, and maintain the stability of back pressure through the shutters of each sector until the frequency of the four circulating water pumps drops to the minimum operating frequency and maintains the same outlet pressure.

[0017] Compared with the prior art, the present invention has the following technical effects: The present invention provides an automatic control method for a circulating water system with two units on one tower, which can control the circulating water pumps of two units, the intercooling tower sectors and the related valve systems to complete the operation mode of the circulating water system with "two units on one tower" under low-load conditions in winter. The operation flexibility and economy of the main machine circulating water system are improved. The heat loads of the two units are gathered to an intercooling tower through the circulating water system, which effectively ensures the safe and stable operation of the intercooling circulating water systems of the two units in extremely cold weather in winter.

[0018] When two units are cut off or operated in deep adjustment conditions in extremely cold winter weather, the exhaust flow of the low-pressure cylinder is reduced and the heat load drops sharply. Under this condition, the "two machines on one tower" operation mode of the circulating water system of the two units avoids the occurrence of large-scale freezing accidents in the sectors due to insufficient heat load of the intercooling tower. The automatic control method and device of the "two machines on one tower" circulating water system provided in this application can realize the full-process automatic control of the intercooling circulating water system, reduce the cumbersome operating steps of the operating personnel, avoid the possible mistakes caused by manual operation of the operating personnel, and realize accurate judgment and control during the commissioning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a flow chart of the automatic control method of "two machines on one tower" for circulating water in the embodiment of the present application; Figure 2 This is a flow chart of controlling two machines to stop one circulating pump and adjust the frequency in an embodiment of the present application; Figure 3 A flow chart of controlling two circulating pumps to automatically adjust pressure and prepare for pumping in an embodiment of the present application; Figure 4 This is a flow chart of controlling the opening of the connecting valve to realize the parallel operation of circulating water in the embodiment of the present application; Figure 5 Flow chart for controlling and adjusting the liquid level of the cold expansion water tank between two machines in the embodiment of the present application Figure 6 This is a flow chart of controlling the removal of a sector of an intercooler tower and automatically adjusting the back pressure in an embodiment of the present application; Figure 7 This is a structural diagram of the control unit of the intercooling circulating water system in the embodiment of the present application; Figure 8 This is a structural diagram of a circulating water pump control unit in an embodiment of the present application; Fig. 9 This is a structural diagram of the intermediate cooling tower control unit in the embodiment of the present application; Fig.10 This is a flow chart of a control method for automatic startup of "two units on one tower" of a circulating water system of two units in an embodiment of the present application; Fig.11 This is a control system diagram for the coordinated operation of the circulating water systems of two typical indirect air-cooling units in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] The acquisition, storage, use and processing of data in the technical solution of this application comply with the relevant provisions of national laws and regulations.

[0023] In the embodiments, see Figure 1 In order to control the parallel operation of the two units' circulating water systems under low-load conditions in winter and completely switch to one intercooling tower, the heat loads of the two units are gathered to one intercooling tower through the circulating water system, effectively ensuring the safe and stable operation of the intercooling circulating water systems of the two units in extremely cold winter weather. This application provides an automatic control method for a "two units on one tower" circulating water system, including: S101: Acquire the operating status of two units, including the start / stop status and load of the first unit, and the start / stop status and load of the second unit; Obtain the operating status and parameters of the respective circulating water pumps in the circulating water systems of the two intercooling units; including the three circulating water pumps of the first unit and the three circulating water pumps of the second unit; the valves include the respective valves of the circulating water systems of the two units and the communication valves of the circulating water systems of the two units; The operation status of the intercooling tower sectors of the two units is obtained, including the switching status of the intercooling sector of the first unit and the switching status of the intercooling sector of the second unit.

[0024] S102: Control the circulating water pumps and valves in the cold circulating water system between the two units, and when the operating frequencies and outlet pressures of the circulating water pumps of the two units are adjusted to be consistent, gradually open the communication valves of the circulating water systems of the two units to make the circulating water systems of the two units enter parallel operation.

[0025] S103: After the system pressure is stable and the liquid levels of the expansion water tanks of the two intercooling towers are consistent, the sectors of the intercooling towers to be shut down are cut off in turn. That is, the inlet and return valves of the sectors of the intercooling tower of the first unit or the inlet and return valves of the sectors of the intercooling tower of the second unit are closed.

[0026] S104: According to the back pressure of the two units, adjust the operating frequency of the two units' respective circulating pumps and the shutter opening of the intercooling sector area put into operation, while taking into account the changes in the liquid level of the two intercooling tower expansion water tanks, maintain the stability of the unit back pressure, and make the back pressure deviation of the two units not exceed 5kpa, and the maximum upper limit does not exceed 15kpa. Otherwise, the removed intercooling tower sector must be put into operation to ensure the safety of the unit.

[0027] Understandably, Fig.11 The invention shows a typical control system for circulating water liaison operation of two indirect air-cooling units, including: controller 1, circulating water pump 2 of the first unit, circulating water pump 3 of the first unit, circulating water pump 4 of the first unit, circulating water pump 5 of the second unit, circulating water pump 6 of the second unit, circulating water pump 7 of the second unit, circulating pump outlet valve 8 of the first unit #1, circulating pump outlet valve 9 of the first unit #2, circulating pump outlet valve 10 of the first unit #3, circulating pump inlet valve 11 of the first unit #1, circulating pump inlet valve 12 of the first unit #2, circulating pump inlet valve 13 of the first unit #3, circulating pump outlet valve 14 of the second unit #1, outlet valve 15 of the second unit #2, circulating pump outlet valve 16 of the second unit #3 、The second unit #1 circulating pump inlet valve 17、The second unit #2 circulating pump inlet valve 18、The second unit #3 circulating pump inlet valve 19、The first unit condenser 20、The second unit condenser 21、The first cold water pipe connecting valve 22、The second cold water pipe connecting valve 3、The hot water pipe connecting valve (1) 24, second hot water pipe connecting valve 5, first unit intercooling tower 26, second unit intercooling tower 27, first unit expansion water tank 28, first unit i-th sector 29, first unit expansion water tank overflow valve 30, first unit expansion water tank drain valve 31, first unit i-th sector return valve 32, first unit i-th sector inlet valve 33, first unit make-up water pump 34, second unit expansion water tank 35, second unit i-th sector 36, second unit expansion water tank overflow valve 37, second unit expansion water tank drain valve 38, second unit i-th sector return valve 39, second unit i-th sector inlet valve 40, second unit make-up water pump 41.

[0028] The exhaust steam of the steam turbine of the first unit is cooled by circulating water in the condenser 20 of the first unit. The heated circulating water is pressurized by the circulating water pumps 2, 3, and 4 of the first unit, and enters the intercooling tower 26 of the first unit through the hot water main pipe. The circulating water enters the i-th sector 29 of the intercooling tower of the first unit through the i-th sector inlet valve 33 for heat exchange cooling, and the heat in the circulating water is taken away by the natural wind of the environment. Then it flows out from the i-th sector return valve 32, passes through the circulating water cooling main pipe and enters the condenser 20 of the first unit again, completing a cycle. The circulation process of the second unit is the same as that of the first unit. The circulating water cooling main pipe of the first unit is connected to the circulating water cooling main pipe of the second unit through the first and second cold water pipe connecting valves 2 and the second cold water pipe connecting valves 3, and the circulating water hot water main pipe of the first unit is connected to the circulating water hot water main pipe of the second unit through the first and second hot water pipe connecting valves 4 and the second hot water pipe connecting valves 5. The circulating water pumps 2, 3, and 4 of the first unit adjust the pressure p1 of the circulating water outlet main pipe of the first unit by adjusting the frequency HZ1 / HZ2 / HZ3 of the inverter control, and the liquid level h1 of the expansion water tank 28 of the first unit is jointly regulated and maintained by the underground water tank make-up pump 34, the overflow valve 30, and the drain valve 31. The back pressure P1 of the condenser 20 of the first unit is maintained within the normal operating range by jointly regulating the shutter opening k1i of the i-th sector 29 of the first unit and the circulating water pump frequency HZ1i. The circulating water pumps 5, 6, and 7 of the second unit adjust the pressure p2 of the circulating water outlet main pipe of the second unit by adjusting the frequency HZ4 / HZ5 / HZ6 of the inverter control, and the liquid level h2 of the expansion water tank 35 of the second unit is jointly regulated and maintained by the underground water tank make-up pump 41, the overflow valve 37, and the drain valve 38. The back pressure P2 of the condenser 21 of the first unit is maintained within the normal operating range by jointly adjusting the shutter opening k2i of the i-th sector 36 of the second unit and the circulating water pump frequency HZ2i.

[0029] Under winter conditions, when the load of the first and second units is adjusted to 30% of the rated load or below, and when there is a demand for heating, a large amount of steam is often required to be extracted from the intermediate pressure cylinder, and some units even have to cut cylinder operation. Under this condition, the exhaust flow of the low-pressure cylinder of the two units drops sharply, and the reduction of the condenser heat load will further reduce the heat absorption of the circulating water. Therefore, the heat load of the intercooler tower is also reduced at any time. In extremely cold winter weather, even if the shutters of the intercooler tower sectors are all closed, the minimum heat for antifreeze cannot be maintained. Therefore, the circulating water system of the first unit and the circulating water system of the second unit are operated in parallel, and the heat of the condensers of the two units is gathered to an intercooler tower, realizing the "two units on one tower" operation mode, maintaining the minimum heat load, and ensuring that the intercooler tower will not threaten the safe operation of the unit due to freezing.

[0030] From the above description, it can be seen that the automatic control method of the "two machines on one tower" circulating water system of the two units provided in this application can control the inter-cooling circulating water system of the two units to complete the "two machines on one tower" operation mode under winter conditions, cut off the operation of the inter-cooling tower of one unit, and make the condenser heat of the two units maintain the operation of one inter-cooling tower, effectively ensuring the safe and stable operation of the inter-cooling circulating water system of the two units. The automatic control method and device of the "two machines on one tower" inter-cooling circulating water system provided in this application can realize the full-process automatic control of the switching of the inter-cooling circulating water system between the two units, reduce the cumbersome operating steps of the operating personnel, avoid the mistakes that may be caused by the manual operation of the operating personnel, and realize accurate judgment and control during the commissioning process.

[0031] It can be understood that the controller 1 collects the operating status and inlet and outlet valve switch status of the three circulating water pumps of the first unit in real time through the signal cable, the frequency of the three circulating water pumps HZ1 / HZ2 / HZ3, the circulating water pump outlet main pipe pressure, temperature p1t1, the expansion water tank level h1 of the intercooling tower of the first unit, the shutter opening k1i of the i-th sector, the make-up water pump status, the condenser back pressure P1 of the second unit, collects the operating status and inlet and outlet valve switch status of the three circulating water pumps of the second unit, the frequency HZ4 / HZ5 / HZ6 of the three circulating water pumps, the circulating water pump outlet main pipe pressure, temperature p2t2, the expansion water tank level h2 of the intercooling tower of the second unit, the shutter opening k2i of the i-th sector, the condenser back pressure P2 of the second unit, and the controller 1 also collects the switch status of the cold water connecting valve 1 / 2 and the hot water connecting valve 1 / 2 of the circulating water system of the first unit and the circulating water system of the second unit through the signal cable. The start and stop of four charging pumps (only one is shown in the figure) and the switch of their outlet valves (not shown in the figure) in the water tanks under the intercooling towers of the first unit and the second unit are also collected. The sampling scanning period of the controller 1 is preferably 200ms.

[0032] From the above description, it can be seen that the automatic control method of the "two machines on one tower" indirect cooling circulating water system provided in this application can obtain the operating parameters of each circulating water pump in the circulating water system of the two indirect cooling units, the indirect cooling tower equipment system parameters and the status of each relevant valve.

[0033] Figure 2 This is a specific embodiment of the automatic control method of the "two machines on one tower" indirect cooling circulating water system implemented in the embodiment of the present application.

[0034] In the embodiments, see Figure 2, the circulating water pumps include three circulating water pumps of the first unit and three circulating water pumps of the second unit; the three circulating water pumps of the first unit are in operation; the valves include the inlet and outlet valves of the circulating water pumps of the first unit, and the three circulating water pumps of the second unit are in operation; the valves include the inlet and outlet valves of the circulating water pumps of the first unit, the inlet and outlet valves of the circulating water pumps of the second unit, and the communication valves of the circulating water systems of the two units, so that the circulating water systems are ready for parallel operation, It includes: stopping the operation of the #3 circulating water pump of the first unit; stopping the operation of the #3 circulating water pump of the second unit and closing the outlet valve corresponding to the pump; so as to reduce the flow of the circulating water systems of the two units (S201); when it is detected that the circulating water system of the first unit is in a two-pump operation state, and the circulating water system of the second unit is in a two-pump operation state; gradually reducing the frequency of all running circulating water pumps of the two units to the lowest frequency, maintaining the stability of the back pressure through the respective sector shutters, until the frequency of the four circulating water pumps drops to the lowest operating frequency of 29Hz, adjusting the outlet pressure to 0.38Mpa, and keeping the outlet pressure consistent (S202).

[0035] It can be understood that in this embodiment, the #3 circulating water pumps of the first unit and the second unit are stopped. In other words, only two circulating water pumps of the first unit and the second unit are in operation. The hot and cold water connecting valves of the circulating water system are opened, the inlet and return valves of the intercooler sector of the second unit are closed, and the shutter opening of the intercooler sector is adjusted to maintain the back pressure operation of the unit. Fig.10 Step 1001, step 1003, step 1004, step 1006, step 1007 and step 1009. Under this operating condition, the intercooling circulating water system of the two units is switched from operating with two intercooling towers to operating with one intercooling tower.

[0036] Step 1001: Stop the No. 3 circulating water pump 4 of the first unit and close its outlet valve 10, stop the No. 3 circulating water pump 7 of the second unit and close its outlet valve 16. Maintaining the operation of two pumps in each of the circulating water systems of the two units, maintaining the circulation path of the circulating water to the intercooler and condenser, and reducing the circulating water flow rate can reduce disturbances during parallel operation.

[0037] Step 1002: Reduce the frequency of the first unit #1 circulating water pump 2 and #2 circulating water pump 3 to 29Hz, maintain the outlet pressure p1 to 0.38Mpa, reduce the frequency of the second unit #1 circulating water pump 5 and #2 circulating water pump 6 to 29Hz, maintain the pumping pressure p2 to 0.38Mpa, and check whether the pressure, temperature and operating status of the circulating water system are normal. When |p1-p2|<0.05Mpa, the circulating water system meets the conditions for entering parallel operation.

[0038] Step 1003: Open the first and second cold water pipe connecting valves 2 by 10% to check whether the pressure and temperature of the cold water main pipe are normal; open the first and second hot water pipe connecting valves 4 by 10% to check whether the pressure and temperature of the hot water main pipe are normal. The valves are mainly checked to be able to move flexibly and can be closed at any time in abnormal situations to switch back to the original unit operation mode.

[0039] Step 1004: Open the second cold water pipe connecting valve 35% of the opening, maintain for 5 to 10 minutes, check the fluctuation of the liquid levels h1 and h2 of the expansion water tanks of the two intercooling towers. The liquid level h2 of the second unit may fluctuate slightly. Monitor the liquid level h2 of the intercooling tower of the second unit to be within the controllable range. Open the second hot water pipe connecting valve 55% of the opening, check the circulating water pipe pressures p1 and p2 of the first unit and the second unit, wait until the system pressures p1 and p2 of the two units are balanced and satisfy |p1-p2|<0.05Mpa, and the liquid levels h1 and h2 of the two expansion water tanks are consistent and satisfy |h1-h2|<300mm; continue to operate repeatedly with an opening of 5% until the cold connecting valve (2) 23 and the hot water connecting valve (2) 25 are fully opened.

[0040] Step 1005: Detect that the liquid level h1 of the expansion water tank 28 of the first unit is between 1500mm and 2500mm. If the liquid level h1 is lower than the lower value of 1500mm, start the underground water tank replenishment pump 34 to inject water into the expansion water tank 28 to the normal liquid level. If the liquid level h1 is higher than the higher value of 2500mm, open the overflow valve 30 to lower the liquid level to the normal value. If the liquid level still rises after the overflow valve 30 is opened, open the drain valve 31 to maintain the liquid level at the normal value.

[0041] The liquid level h2 of the expansion water tank 35 of the second unit is detected to be between 1500mm and 2500mm. If the liquid level h1 is lower than the lower value of 1500mm, the underground water tank replenishment pump 41 is started to inject water into the expansion water tank 35 to the normal liquid level. If the liquid level h1 is higher than the higher value of 2500mm, the overflow valve 37 is opened to lower the liquid level to the normal value. If the liquid level still rises after the overflow valve 37 is opened, the drain valve 38 is opened to maintain the liquid level at the normal value.

[0042] Step 1006: Cut off the operation of the intercooler of the second unit, close the water inlet electric valve 39 and the water return electric valve 40 of the i-th sector 36 of the second unit in sequence, and observe the change of the back pressure P2 of the second unit. After all are closed, if there is no obvious change in the back pressures P1 and P2 of the two units, open the drain valve of the i-th sector 36 (not shown in the figure), and cut off the input sector i in sequence.

[0043] Step 1007: According to the increase of the back pressure P1 of the first unit and the back pressure P2 of the second unit, gradually increase the shutter opening k1 of the first unit sector 29 to maintain the back pressure P1 and P2 of the two units stable, until the back pressure of the two units |P1-P2| < 5kpa, and max (P1, P2) < 15kpa.

[0044] Step 1008: After detecting that the shutter 29 of the i-th sector of the first unit is fully opened, if the back pressures P1 and P2 of the two units are still rising, the frequencies HZ1 and HZ2 of the circulating water pumps 2 and 3 of the first unit can be increased, and the frequencies HZ4 and HZ5 of the circulating water pumps 5 and 6 of the second unit can be increased until the back pressures P1 and P2 are stable and controllable. If the back pressure P2 of the second unit is higher than the back pressure P1 of the first unit by 5kpa, the frequencies HZ4 and HZ5 of the circulating water pumps 5 and 6 of the second unit will continue to be increased, and differential flow regulation will be performed to maintain the back pressure deviations P1 and P2 within the required range.

[0045] Step 1009: Detect the load changes of the first unit and the second unit. The shutter opening k1 of the i-th sector of the first unit and the circulating pump frequency HZi of the two units jointly adjust the unit back pressures P1 and P2 to meet the operation requirements and realize the "two machines on one tower" operation mode of the circulating water system.

[0046] From the above description, it can be seen that the automatic control method of the "two machines on one tower" intercooling circulating water system provided in the present application can control the start and stop of the pump and the switching of each valve in the intercooling unit circulating water system, and the circulating water pump of the first unit and the circulating water pump of the second unit adjust the operating status and outlet pressure so that the circulating water of the two machines enters a parallel operation ready state.

[0047] Figure 3 This is a specific embodiment of the automatic control method for realizing the parallel operation of the circulating water systems of two machines in the embodiment of the present application.

[0048] In the embodiments, see Figure 3 The operating parameters and communication valve status of the circulating water pumps of the two units are correct, and the number of switching on and off sectors of the cooling tower between the two units meets the requirements.

[0049] The method includes: when it is detected that the operating parameters of the four circulating water pumps of the two units are consistent and the states of the valves are correct, preparing to open the circulating water cold and hot water communication valves of the two units (S301); by detecting the operating parameters of the two circulating water pumps of the first unit and whether the corresponding outlet doors and inlet doors are in a fully open state, judging that the number of cold sectors put into use between the first unit and the second unit is greater than 1 (S302); by detecting whether the outlet door and inlet door of the circulating water pump of the first unit are in a fully open state, and detecting the circulating water system pressure of the first unit, after the frequency is adjusted for a preset time period, whether the deviation between the outlet main pipe pressure of the circulating water pump of the first unit and the circulating water main pipe pressure of the second unit is less than a preset threshold value, Determine whether the circulating water pump of the first unit meets the conditions for parallel operation (S303); by detecting whether the outlet gate and the inlet gate of the circulating water pump of the second unit are both in the fully open state, and detecting the pressure of the circulating water system of the second unit, after the preset time period of frequency adjustment, whether the deviation between the outlet main pipe pressure of the circulating water pump of the second unit and the circulating water main pipe pressure of the first unit is less than a preset threshold, determine whether the circulating water pump of the second unit meets the conditions for parallel operation (S304); if it is determined that the deviation between the circulating water main pipe pressure of the first unit and the circulating water main pipe pressure of the second unit is less than the preset threshold, control the opening of the hot and cold water connecting valves of the circulating water systems of the two units to realize the parallel operation of the circulating water systems of the two units (S305).

[0050] Figure 4 This is a specific embodiment of the automatic control method of the "two machines on one tower" indirect cooling circulating water system implemented in the embodiment of the present application.

[0051] In the embodiments, see Figure 4 The valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the connecting valves of the circulating water systems of the two units; the connecting valves include the first cold water pipe connecting valve, the second cold water pipe connecting valve, the first hot water pipe connecting valve, and the second hot water pipe connecting valve. Including: S401: First gradually open the first cold water pipe connecting valve to 10%, check that there is no obvious change in the parameters such as the pressure and temperature of the cold water main pipe, and confirm that the second cold water pipe connecting valve is tightly closed; S402: Open the first hot water pipe connecting valve to 10% again, check that there is no obvious change in the parameters such as the pressure and temperature of the hot water main pipe, and confirm that the second hot water pipe connecting valve is tightly closed; S403: Slowly open the second cold water pipe connecting valve to 5% opening, observe the changes in the parameters of the cold water main pipe and the liquid level fluctuations in the expansion water tanks of the two intercoolers. If there is no obvious change in the water level or the change trend is small, continue to open the second cold water pipe connecting valve to 10%, continue to observe and repeat the operation until the second cold water pipe connecting valve is fully opened.

[0052] S404: Finally, open the second hot water pipe connecting valve to 5%, observe the system parameters, and continue to open it to 10%. If there is no abnormality, repeat the operation until it is fully opened. The circulating water systems of the two units are operated in parallel.

[0053] Figure 5 The embodiment of the present application realizes the automatic control method of the "two machines on one tower" in the indirect cooling circulating water system Specific embodiments. Figure 5 The expansion water tank and liquid level include the expansion water tank and liquid level of the first unit and the expansion water tank and liquid level of the second unit; the overflow valve and drain valve include the overflow valve and drain valve of the expansion water tank of the intercooler tower of the first unit and the overflow valve and drain valve of the expansion water tank of the intercooler tower of the second unit.

[0054] S501: Detect whether the liquid level in the expansion water tank of the intercooler of the first unit is within the safe operating range. If the liquid level exceeds the high liquid level alarm value, control the overflow valve and the drain valve to drain water to the normal value; if the liquid level drops to the low liquid level alarm value, control the water supply pump to start replenishing water to the expansion water tank to the normal value; S502: Detecting whether the liquid level of the expansion water tank of the intercooler of the second unit is within the safe operating range, if it exceeds the high liquid level alarm value, control the opening of the overflow valve and the drain valve to drain water to the normal value; if it drops to the low liquid level alarm value, control the water supply pump to start replenishing water to the expansion water tank to the normal value; S503: By adjusting the frequency of the circulating water pumps of the two units to operate differently, the pressure deviation caused by factors such as pipe resistance and temperature is offset, the pressure of the circulating water main pipe is made consistent, and then the liquid level of the two expansion water tanks is ensured to be consistent and stable.

[0055] Figure 6 The embodiment of the present application realizes the automatic control method of "two machines on one tower" of the indirect cooling circulating water system In the embodiments, see Figure 6 The i-th sector of the intercooling tower includes the i-th sector of the intercooling tower of the first unit and the i-th sector of the intercooling tower of the second unit, the shutter opening includes the shutter opening of the first unit sector and the shutter opening of the second unit, and the back pressure includes the back pressure of the first unit and the back pressure of the second unit.

[0056] S601: After the circulating water systems of the two units are running stably in parallel, start to cut off the intercooler to be withdrawn, that is, close the sector inlet and return valves of the intercooler of the first unit or the intercooler of the second unit.

[0057] S602: Control the inlet and return water valves of the i-th sector of the intercooling tower to be closed at the same time. After exiting, monitor the circulating water pressure of the unit to be stable, and the back pressure of the unit to have no obvious change. Open the drain valves of the inlet and return water pipes of the i-th sector of the intercooling tower. Until all sectors are exited, observe that the back pressure of the two units is normal and operates within the allowable range.

[0058] S603: As the sectors are gradually withdrawn, the back pressure of the unit will gradually increase. You can gradually increase the opening of the intercooler shutters on the switching side to adjust the circulating water temperature and control the back pressure change. You can also increase the frequency of the intercooler circulating water pump on the cut-off side and adjust the operating flow and flow rate of the circulating water to achieve back pressure regulation.

[0059] From the above description, it can be seen that the automatic control method of the intercooling circulating water system of two units "two machines on one tower" provided in this application can control the intercooling circulating water system of the two units to realize the operating mode of circulating water "two machines on one tower".

[0060] Based on the same inventive concept, the embodiment of the present application also provides an automatic control device for an intercooled circulating water system with "two machines on one tower", which can be used to implement the method described in the above embodiment, as described in the following embodiment. Since the principle of solving the problem by the automatic control device of the intercooled circulating water system is similar to the automatic control method of the intercooled circulating water system, the implementation of the automatic control device of the intercooled circulating water system can refer to the implementation of the method based on the software performance benchmark determination, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements predetermined functions. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0061] In the embodiments, see Figure 7 , the automatic control device of the circulating water system "two machines on one tower", the four circulating water pumps of the first unit and the second unit are in operation; the valve includes a communication door between the circulating water system of the first unit and the circulating water system of the second unit; the device includes: The operating parameter acquisition unit 701 is used to acquire the loads of the two units, the operating status of the circulating pumps of the two units, the input status of the intercooler sectors and the switch status of related valves; The circulating water pump control unit 702 is used to control the start and stop of the circulating water pump and the opening and closing of the inlet and outlet valves, as well as the frequency adjustment of the circulating pump to control the pressure of the circulating water pipe; The intercooler control unit 703 is used to control the switching of the intercooler sectors, the switching of the inlet and return valves of the i-th sector, and the liquid level of the expansion tank.

[0062] In the embodiments, see Figure 8 , the circulating water pump control unit 702 comprises: A circulating water pump start-stop module 801 is used to control the start-stop of the circulating water pumps of the first unit and the second unit; The pressure balance adjustment module 802 is used to adjust the frequency and speed of the circulating water pumps of the first unit and the second unit so that the outlet circulating water pressure of the circulating water pump of the first unit is balanced with the outlet circulating water pressure of the circulating water pump of the second unit; The valve switch control module 803 is used to control the switches of the inlet and outlet valves of the first unit's circulating water pump, the inlet and outlet valves of the second unit's circulating water pump, and the cold and hot water connection valves of the first unit's circulating water system and the second unit's circulating water system.

[0063] In the embodiments, see Fig. 9 The intercooling tower control unit 703 comprises: The intercooling sector control module 901 is used to control the input and removal of the intercooling sector of the first unit, and control the switch of the inlet and return valves and the drain valve of the i-th sector of the intercooling tower of the first unit; control the input and removal of the intercooling sector of the second unit, and control the switch of the inlet and return valves and the drain valve of the i-th sector of the intercooling tower of the second unit; The expansion water tank liquid level control module 902 is used to detect the change of the liquid level of the expansion water tank of the intercooling tower of the first unit, determine whether the liquid level of the expansion water tank is in an alarm state, and control the expansion water tank overflow valve, the drain valve and the underground water tank water supply pump to adjust the liquid level within the required range; detect the change of the liquid level of the expansion water tank of the intercooling tower of the second unit, determine whether the liquid level of the expansion water tank is in an alarm state, and control the expansion water tank overflow valve, the drain valve and the underground water tank water supply pump to adjust the liquid level within the required range; The circulation pump frequency adjustment module 903 is used to detect the pressure change of the circulation water pump of the first unit and adjust the circulation water pump pressure by adjusting the circulation pump frequency; detect the pressure change of the circulation water pump of the second unit and adjust the circulation water pump pressure by adjusting the circulation pump frequency.

[0064] The operating parameter acquisition unit includes: the acquisition of the operating status and load of the two units, which is used to obtain the real-time load and related parameters of the two units; the acquisition of the operating parameters of the intercooling circulating water system, which is used to obtain the operating parameters of each circulating water pump in the circulating water system of the intercooling unit; the acquisition of the status of each intercooling tower sector and each valve of the system; and the acquisition of the start-up and stop status of each intercooling sector and the switch status of related valves.

[0065] The two units include the start / stop status and load of the first unit, and the start / stop status and load of the second unit; The circulating water pumps include three circulating water pumps of the first unit and three circulating water pumps of the second unit; The valves include respective valves of the circulating water systems of the two units and the connecting valves of the circulating water systems of the two units; the indirect cooling sectors include the indirect cooling sectors of the first unit and the indirect cooling sectors of the second unit.

[0066] The circulating water pump control unit is used to control the start and stop of each circulating pump in the circulating water system of the intercooler unit, adjust the frequency, and switch each valve. The operating state of the circulating water pump of the first unit and the circulating water pump of the second unit is adjusted so that the circulating water systems of the two units enter a state of preparation for parallel operation; The intercooler control unit is used to control the switching of each intercooler sector, the switching of the inlet and return valves and the drain valve of each sector of the intercooler tower of the first unit and the second unit; and the control of the liquid level of the expansion water tanks of the two intercoolers, the control of the overflow valve, the drain valve and the make-up water pump of the expansion water tank of the intercooler tower of the first unit and the expansion water tank of the second unit, so that the liquid level trends of the two expansion water tanks are consistent and stable.

[0067] Furthermore, in the automatic control device for the circulating water pump, the circulating water pumps of the first unit and the second unit are both in operation; the frequency conversion frequency is in a controllable state. The circulating pump control unit includes: A start / stop module for the first unit's circulating water pump, used for controlling the start / stop state of the first unit's circulating water pump; The second unit circulating water pump start-stop module is used to control the start-stop state of the second unit circulating water pump; The automatic control system of the two-unit-on-one tower of the thermal power unit circulating water system includes: The first unit circulating water pump pressure regulating module is used to adjust the first unit circulating water pump frequency when it is detected that the outlet main pipe pressure of the first unit circulating water pump and the second unit circulating water main pipe pressure deviation is less than a preset threshold; The second unit's circulating water pump pressure regulating module is used to adjust the second unit's circulating water pump frequency when it is detected that the outlet main pipe pressure of the second unit's circulating water pump deviates from the first unit's circulating water main pipe pressure less than a preset threshold, so that the circulating water systems of the two units enter a parallel operation state.

[0068] Furthermore, when the outlet main pipe pressures of the circulating water pumps of the first unit and the second unit are substantially the same; the valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the communication valves of the circulating water systems of the two units; the valve control unit includes: Cold water pipe connecting valve control module, open the cold water pipe connecting valve 1 to 10%, check that there is no obvious change in parameters such as the cold water main pipe pressure and temperature, and confirm that the cold water pipe connecting valve 2 is tightly closed; then slowly open the cold water pipe connecting valve 2 to 5% to observe the changes in the cold water main pipe parameters and the liquid level fluctuations of the two intercooler tower expansion water tanks. If there is no obvious change in the water level or the change trend is small, continue to open the cold water pipe connecting valve 2 to 10%, continue to observe and repeat the operation until the cold water pipe connecting valve 2 is fully opened.

[0069] The hot water pipe connecting valve control module opens the hot water pipe connecting valve 1 to 10%, checks the hot water main pipe pressure, temperature and other parameters without obvious changes, and confirms that the hot water pipe connecting valve 2 is tightly closed; finally, open the hot water pipe connecting valve 2 to 5%, observe the system parameters, and continue to open it to 10% if there is no abnormality, repeat the operation until it is fully opened. The circulating water systems of the two units are operated in parallel.

[0070] A pressure balance adjustment module, used for adjusting the frequency and rotation speed of the circulating water pumps of the first unit and the second unit, so that the outlet circulating water pressure of the circulating water pump of the first unit is balanced with the outlet circulating water pressure of the circulating water pump of the second unit; Furthermore, the intercooling tower control unit comprises: The liquid level control module of the expansion water tank of the intercooler of the first unit is used to detect whether the liquid level of the expansion water tank of the intercooler of the first unit is within the safe operating range. When the water level exceeds the high liquid level alarm value, the overflow valve and the drain valve are controlled to open to discharge water to the normal value; when the water level drops to the low liquid level alarm value, the water make-up pump is controlled to start to make water to the expansion water tank to the normal value.

[0071] The liquid level control module of the expansion water tank of the intercooler of the second unit is used to detect whether the liquid level of the expansion water tank of the intercooler of the second unit is within the safe operating range. When the water level exceeds the high liquid level alarm value, the overflow valve and the drain valve are controlled to open to discharge water to the normal value; when the water level drops to the low liquid level alarm value, the water make-up pump is controlled to start to make water to the expansion water tank to the normal value.

[0072] The first inter-unit cold sector control module is used to control the switch of the first inter-unit cold sector inlet and return valves and drain valves, and the size of the opening of the corresponding sector shutters by detecting whether the inlet and return valves and drain valves of each sector of the first unit are in a fully open or fully closed state, and detecting the opening of the corresponding sector shutters; and start or cut off the operation of the first inter-unit cold sector; The second inter-unit cold sector control module is used to control the switch of the first inter-unit cold sector inlet and return valves and drain valves, and the size of the opening of the corresponding sector shutters by detecting whether the inlet and return valves and drain valves of each sector of the second unit are in a fully open or fully closed state, and detecting the opening of the corresponding sector shutters; and start or cut off the operation of the first inter-unit cold sector; Furthermore, the circulating water pump control unit also includes: by adjusting the differential operation frequencies of the circulating water pumps of the two units, the pressure deviation caused by factors such as pipe resistance and temperature is offset, so as to achieve consistent pressure in the circulating water main pipe, thereby ensuring that the liquid levels of the two expansion water tanks are consistent and stable.

[0073] Furthermore, the intercooler control unit also includes: after the circulating water systems of the two units are running stably in parallel, the intercooler to be withdrawn begins to be cut off, that is, the sector inlet and return valves of the intercooler of the first unit or the intercooler of the second unit are closed. The inlet and return valves of the i-th sector of the intercooler are controlled to be closed at the same time, and after withdrawal, the circulating water pressure of the unit is monitored to be stable, and there is no obvious change in the back pressure of the unit, and the drain valves of the inlet and return pipes of the i-th sector of the intercooler are opened at the same time. Until all sectors are withdrawn, the back pressure of the two units is observed to be normal and operating within the allowable range, and the parameters of the circulating water systems of the two units are monitored to be stable, so as to realize the "two units on one tower" operation of the circulating water systems of the two units.

[0074] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. An automatic control method for a tower on two units of a circulating water system of a thermal power unit, characterized in that: include: Obtaining the start / stop status and load of the first unit, and the start / stop status and load of the second unit; Obtain the operating status and parameters of the three circulating water pumps of the first unit and the three circulating water pumps of the second unit in the circulating water system of the two intercooling units; obtain the intercooling sector switching status of the first unit and the intercooling sector switching status of the second unit; When the operating frequency and outlet pressure of the circulating water pumps of the two units are adjusted to be consistent, the communication valves of the circulating water systems of the two units are opened to make the circulating water systems of the two units run in parallel; After the system pressure is stable and the liquid levels of the expansion water tanks of the two intercooling towers are consistent, cut off the sectors of the intercooling towers to be shut down in turn, that is, close the inlet and return valves of the sectors of the intercooling tower of the first unit or the inlet and return valves of the sectors of the intercooling tower of the second unit; According to the back pressure of the two units, adjust the operating frequency of the circulation pumps of the two units and the shutter opening of the intercooler sector put into operation, while taking into account the changes in the liquid level of the two intercooler tower expansion tanks to maintain the back pressure of the units stable. Make the back pressure deviation of the two units not exceed 5kpa, and the maximum upper limit does not exceed 15kpa, otherwise the cut-off intercooler tower sector will be put into operation.

2. The automatic control method for two units on one tower of a circulating water system of a thermal power unit according to claim 1 is characterized in that: The loads of both units are lower than 30% of the rated load, and the ambient temperature is lower than 20°C; the three circulating water pumps of the first unit are in operation, and the three circulating water pumps of the second unit are in operation; the valves include the inlet and outlet valves of the circulating water pump of the first unit, the inlet and outlet valves of the circulating water pump of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems are ready for parallel operation, including: Stop one circulating water pump of the first unit; stop one circulating water pump of the second unit; reduce the flow of the circulating water systems of the two units and enter parallel operation.

3. The automatic control method for two units on one tower of a circulating water system of a thermal power unit according to claim 2 is characterized in that: The circulating water system of the first unit is in a state where two pumps are running; the circulating water system of the second unit is in a state where two pumps are running; the valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems enter a state ready for parallel operation, including: Reduce the frequency of all running circulating water pumps of the two units, and maintain the stability of back pressure through the shutters of each sector until the frequency of the four circulating water pumps drops to the minimum operating frequency and maintains the same outlet pressure.

4. The automatic control method for two units on one tower of a thermal power plant circulating water system according to claim 1, characterized in that: When the operating parameters of the four circulating water pumps of the two units are consistent and the status of the valves are correct, prepare to open the circulating water cooling and hot water communication valves of the two units, including: By detecting the operating parameters of the two circulating water pumps of the first unit and whether the corresponding outlet doors and inlet doors are both in a fully open state, it is determined that the number of intercooling sectors in the first unit is greater than 1; By detecting the operating parameters of the two circulating water pumps of the second unit and whether the corresponding outlet doors and inlet doors are both in a fully open state, it is determined that the number of intercooling sectors in the second unit is greater than 1; By detecting whether the outlet door and the inlet door of the circulating water pump of the first unit are both in the fully open state, and detecting the pressure of the circulating water system of the first unit, after the preset time period of frequency adjustment, whether the deviation between the outlet main pipe pressure of the circulating water pump of the first unit and the pressure of the circulating water main pipe of the second unit is less than a preset threshold, it is judged whether the circulating water pump of the first unit meets the conditions for parallel pumping; By detecting whether the outlet door and the inlet door of the circulating water pump of the second unit are both in the fully open state, and detecting the circulating water system pressure of the second unit, after the frequency adjustment preset time period, whether the deviation between the outlet main pipe pressure of the circulating water pump of the second unit and the circulating water main pipe pressure of the first unit is less than a preset threshold, it is judged whether the circulating water pump of the second unit meets the pumping conditions; If it is determined that the deviation between the circulating water main pipe pressure of the first unit and the circulating water main pipe pressure of the second unit is less than the preset threshold, the cold and hot water connecting valves of the circulating water systems of the two units are controlled to open to realize parallel operation of the circulating water systems of the two units.

5. The automatic control method for two units on one tower of a circulating water system of a thermal power unit according to claim 1, characterized in that: The cold and hot water pipe connecting valves include the first cold water pipe connecting valve and the second cold water pipe connecting valve, the first hot water pipe connecting valve and the second hot water pipe connecting valve respectively; when opening the connecting valves of the circulating water systems of the two units, first open the first cold water pipe connecting valve to 10%, check that the pressure, temperature and other parameters of the cold water main pipe have not changed, and confirm that the second cold water pipe connecting valve is tightly closed; then open the first hot water pipe connecting valve to 10%, check that the pressure, temperature and other parameters of the hot water main pipe have not changed, and confirm that the second hot water pipe connecting valve is tightly closed; then open the second cold water pipe connecting valve to 5% opening, observe the changes in the parameters of the cold water main pipe and the liquid level fluctuations of the expansion water tanks of the two intercooling towers, if the water level has not changed, continue to open the second cold water pipe connecting valve to 10%, continue to observe and repeat the operation until the second cold water pipe connecting valve is fully opened; finally open the second hot water pipe connecting valve to 5%, observe the system parameters, and continue to open it to 10% if there is no abnormality, repeat the operation until all are opened, and the circulating water systems of the two units are connected in parallel.

6. The automatic control method for two units on one tower of a circulating water system of a thermal power unit according to claim 5, characterized in that: During the opening of the circulating water cooling and hot water connecting valves of the two units, if the detected liquid level continues to drop to a lower value, the underground water tank replenishment pump is started to continuously replenish water to stabilize the expansion tank liquid level; Further, by adjusting the frequencies of the circulating water pumps of the two units to operate differentially, the pressure deviation can be corrected and the pressure of the circulating water pipe can be made consistent.

7. The automatic control method for two units on one tower of a thermal power plant circulating water system according to claim 1, characterized in that: The i-th sector of the intercooling tower includes the i-th sector of the intercooling tower of the first unit and the i-th sector of the intercooling tower of the second unit, the shutter opening includes the shutter opening of the sector of the first unit and the shutter opening of the second unit, and the back pressure includes the back pressure of the first unit and the back pressure of the second unit; After the circulating water systems of the two units are in parallel and running stably, start to cut off the intercooler to be withdrawn, that is, close the sector inlet and return valves of the intercooler of the first unit or the intercooler of the second unit; Control the inlet and return valves of the i-th sector of the intercooler to close at the same time. After exiting, monitor that the circulating water pressure of the unit is stable and the back pressure of the unit does not change. Open the drain valves of the inlet and return pipes of the i-th sector of the intercooler until all sectors are exited. Observe that the back pressure of the two units is normal and operates within the allowable range.

8. The automatic control method for two units on one tower of a thermal power plant circulating water system according to claim 7, characterized in that: As the sector is withdrawn, the back pressure of the unit will increase. The shutter opening of the intercooler on the switching side will be opened wider, the circulating water temperature will be adjusted, the back pressure change will be controlled, the frequency of the circulating water pump of the intercooler on the cut-off side will be increased, the operating flow rate and flow velocity of the circulating water will be adjusted, and the back pressure will be regulated.

9. The automatic control system of one tower on two units of the circulating water system of a thermal power unit is characterized by: include: A data acquisition module, used to acquire the start / stop status and load of the first unit, and the start / stop status and load of the second unit; Obtain the operating status and parameters of the three circulating water pumps of the first unit and the three circulating water pumps of the second unit in the circulating water system of the two intercooling units; obtain the intercooling sector switching status of the first unit and the intercooling sector switching status of the second unit; The regulating module is used to adjust the operating frequency and outlet pressure of the circulating water pumps of the two units to be consistent, and open the communication valves of the circulating water systems of the two units to make the circulating water systems of the two units run in parallel; The cut-off module is used to sequentially cut off the sectors of the intercooler to be withdrawn from operation after the system pressure is stable and the liquid levels of the expansion water tanks of the two intercoolers are consistent, that is, close the inlet and return valves of the sectors of the intercooler of the first unit or the inlet and return valves of the sectors of the intercooler of the second unit; The regulating module is used to adjust the operating frequency of the circulation pumps of the two units and the shutter opening of the intercooling sector put into operation according to the back pressure of the two units, while taking into account the changes in the liquid level of the two intercooling tower expansion tanks to maintain the stability of the unit back pressure, so that the back pressure deviation of the two units does not exceed 5kpa, and the maximum upper limit does not exceed 15kpa, otherwise the cut-off intercooling tower sector will be put into operation.

10. The automatic control system for two units on one tower of the circulating water system of a thermal power unit according to claim 9, characterized in that: The loads of both units are lower than 30% of the rated load, and the ambient temperature is lower than 20°C; the three circulating water pumps of the first unit are in operation, and the three circulating water pumps of the second unit are in operation; the valves include the inlet and outlet valves of the circulating water pump of the first unit, the inlet and outlet valves of the circulating water pump of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems are ready for parallel operation, including: Stop one circulating water pump of the first unit; stop one circulating water pump of the second unit; reduce the flow of the circulating water systems of the two units and enter a parallel operation state; The circulating water system of the first unit is in a state where two pumps are running; the circulating water system of the second unit is in a state where two pumps are running; the valves include the inlet and outlet valves of the two circulating water pumps of the first unit, the inlet and outlet valves of the two circulating water pumps of the second unit, and the connecting valves of the circulating water systems of the two units, so that the circulating water systems enter a state ready for parallel operation, including: Reduce the frequency of all running circulating water pumps of the two units, and maintain the stability of back pressure through the shutters of each sector until the frequency of the four circulating water pumps drops to the minimum operating frequency and maintains the same outlet pressure.

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