A three-dimensional depth double-link reliability optimization method for a hydraulic system of a thermal power unit

Abstract

The present application relates to a kind of hydraulic system three-dimensional depth double linkage reliability optimization method of thermal power generating unit, comprising the following steps: accounting top shaft oil pressure;Select appropriate position as the introduction point, prefabricate bilateral top shaft oil connecting device to realize system three-dimensional depth extension;Water pressure test is carried out to connecting device to ensure the tightness of shutdown mechanism;Connecting device is purged to ensure the cleanliness of oil system;When unilateral failure occurs, operate shutdown switching connecting device, ensure that top shaft oil hydraulic system is normally put into use.The present application ensures that A, B top shaft oil system is mutual standby through the low-cost reasonable modification of oil supply system, once unilateral failure occurs, it can be ensured that top shaft oil hydraulic system is normally put into use by operating shutdown switching device, and maintenance personnel can have sufficient time to overhaul the fault oil pump and other equipment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic systems of thermal power generating units, and particularly relates to a three-dimensional deep double-link reliability optimization method for a hydraulic system of a thermal power generating unit. BACKGROUND

[0002] At present, the steam turbine top shaft oil hydraulic systems (hereinafter referred to as top shaft oil systems) of steam-driven feed water pumps of domestic thermal power generating units are all single-path working systems independent of each other. Since the equipment is expensive, no standby system or equipment is designed. In this case, if the oil supply equipment fails during operation, the steam-driven feed water pump system on the fault side must be stopped immediately for repair, which will seriously affect the unit load and even the stability of the entire power grid system during the repair process. Moreover, a reliable oil film is difficult to form during the shutdown of the steam-driven feed water pump turbine after the failure, which will cause equipment damage accidents such as bearing crushing and rotor bending.

[0003] Therefore, from the engineering technology point of view, it is of great significance to fully utilize the characteristics of the unit itself, seek a simple and effective hydraulic system reliability optimization method, and improve the operation safety of the unit and the energy supply service. SUMMARY

[0004] The purpose of the present application is to solve the problems that the single-path independent oil supply system designed by the conventional method lacks a standby system and it is difficult to ensure the operation safety of the unit, especially the online defect elimination without fluctuation for minor faults. A three-dimensional deep double-link reliability optimization method for a hydraulic system of a thermal power generating unit is proposed. Through the low-cost and reasonable modification of the oil supply system, it is ensured that the A and B top shaft oil systems are standby for each other. Once a fault occurs on one side, the top shaft oil hydraulic system can be ensured to be normally put into use by operating the shut-off valve.

[0005] To achieve the above purpose, the present application adopts the following technical scheme,

[0006] A three-dimensional deep double-link reliability optimization method for a hydraulic system of a thermal power generating unit, comprising the following steps:

[0007] Step 1) Calculate the top shaft oil pressure to ensure that the safety requirements of the unit are met;

[0008] Step 2) Select an appropriate position as a connection point, and prefabricate a double-sided top shaft oil connection device to realize the three-dimensional deep extension of the system;

[0009] Step 3) Perform a water pressure test on the connection device to ensure the tightness of the shut-off mechanism;

[0010] Step 4) Perform a purge on the connection device to ensure the cleanliness of the oil system;

[0011] Step 5) When single-sided failure occurs, the operation shutdown switching connection device is ensured to be normally put into use.

[0012] As a preferred solution, the specific step of step 1) of the application is:

[0013] According to the system parameters of the feed water pump turbine top shaft oil pump performance and pipeline resistance, the feasibility of simultaneously supplying two sets of feed water pump turbines by a single top shaft oil system is calculated and verified:

[0014]

[0015] In the formula, P is the safety oil pressure of the top shaft oil system, P s is the design outlet pressure of the top shaft oil pump, is the pipeline resistance, and N is the resistance part of the connecting pipeline from the standby system to the expected failure system.

[0016] The specific steps of step 2) are:

[0017] An oil pipeline is additionally provided between the A top shaft oil pump and the A steam-driven feed water pump, and control oil valves A1, A2 and A3 are additionally provided on the oil pipeline; control oil valves A4 and A5 are provided on the single-sided self-circulation oil pipeline of the A top shaft oil pump; an oil pipeline is additionally provided between the B top shaft oil pump and the B steam-driven feed water pump, and control oil valves B1, B2 and B3 are provided on the additionally provided oil pipeline; control oil valves B4 and B5 are additionally provided on the single-sided self-circulation oil pipeline of the B top shaft oil pump; an oil pipeline is additionally provided between the A top shaft oil pump and the B top shaft oil pump, and isolation oil valves AB1, AB2, AB3, AB4 and AB5 are provided on the additionally provided oil pipeline.

[0018] The specific steps of step 5) are:

[0019] When the A top shaft oil pump is running, when the A top shaft oil pump suddenly fails and stops running,

[0020] ① The isolation oil valves AB1-AB5 are opened in interlocking, and the interconnection door between the A top shaft oil pump and the B top shaft oil pump is opened; ② The control oil valves B1-B5 are closed in interlocking, and the control oil door of the B top shaft oil pump is closed;

[0021] ③ The B top shaft oil pump is opened in interlocking, and the A steam-driven feed water pump turbine is ensured to work normally.

[0022] When the B top shaft oil pump is running, when the B top shaft oil pump suddenly fails and stops running,

[0023] ①Interlock open isolation oil valve AB1-AB5, open the interconnection door between A top shaft oil pump and B top shaft oil pump; ②Interlock close control oil valve A1-A5, close the control oil door of A top shaft oil pump;

[0024] ③Interlock open A top shaft oil pump, ensure that B steam-driven feed water pump turbine works normally.

[0025] As a preferred solution, the application further comprises step 6), during equipment shutdown and maintenance, test verification is carried out by stopping single-side top shaft oil pump to simulate accident working condition.

[0026] As a preferred solution, the application further comprises step 7), after the unit is started, switching test is carried out in different load intervals for test verification.

[0027] Specific steps of step 6):

[0028] During equipment shutdown and maintenance, by stopping single-side top shaft oil pump to simulate accident working condition, the shutdown switching valve is opened, the double-side top shaft oil pressure is measured, and compared with the double-side system independent operation, so that the requirement is met, and then the running verification test is carried out.

[0029] Specific steps of step 7):

[0030] After the unit is started, switching test is carried out in different load intervals, the test load interval should cover at least the minimum stable operation load, long-term operation load and maximum load of the unit, the whole switching process should not take more than 1 second, and the top shaft oil pressure of the steam-driven feed water pump turbine should be greater than or equal to the safety oil pressure and stable without fluctuation after switching.

[0031] Advantages of the application:

[0032] The application can realize that the single-side top shaft oil system of the feed water pump turbine meets the oil demand of the double-side feed water pump turbine, and can realize fast and undisturbed switching while maintaining stable operation of the unit. When a fault occurs in the oil supply equipment of one side during operation, the other side can immediately switch to emergency oil supply, providing undisturbed repair conditions for the unit, and the main machine can operate normally during the repair process, ensuring stable power supply system of the unit, so that the power generation enterprise can avoid high evaluation of the State Grid Corporation due to affecting people's livelihood. Moreover, a reliable oil film can be formed during shutdown of the steam-driven feed water pump turbine after the fault, effectively avoiding equipment damage accidents such as bearing crushing and rotor bending.

[0033] The present application ensures that A and B top shaft oil systems are standby for each other at very low cost, and once unilateral failure occurs, the top shaft oil hydraulic system can be ensured to be normally put into use by operating the shutoff switching device, and the maintenance personnel can have sufficient time to maintain the failed oil pump and other equipment. While ensuring the reliability of the system, the personal injury caused by rush repair is also reduced.

[0034] According to the actual situation on site, the pipeline laying does not affect the safety and convenience of on-site operation and maintenance, the pipeline transmission resistance is reduced as much as possible, and on the basis of fully utilizing the original system design, appropriate positions are selected as the connection points to ensure smooth oil passage and stable flow as the premise to realize the system three-dimensional deep extension by prefabricating the bilateral top shaft oil connection device. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be further described below in combination with the drawings and specific embodiments. The protection scope of the present application is not limited to the following content.

[0036] Figure 1 is a schematic diagram of the system principle of the present application. DETAILED DESCRIPTION

[0037] EMBODIMENT

[0038] The A and B steam-driven feed water pump turbine top shaft oil hydraulic system of the test unit 600MW unit is manufactured by Jiaxing Aks Mechanical Technology Co., Ltd., with a design maximum pressure of 160Mpa, and adopts a conventional single-path independent oil supply system.

[0039] After repeated calculation and verification of the design scheme for feasibility, the bilateral top shaft oil system oil passage is optimized and reformed by three-dimensional deep double linkage: selecting appropriate positions as connection points, prefabricating bilateral top shaft oil connection devices to realize three-dimensional deep extension of the system, conducting a water pressure test on the connection device to ensure the tightness of the shutoff mechanism, finally connecting the purged connection device to the designated connection point to ensure that no foreign matter is introduced into the oil system. The oil system after the reform is shown in Figure 1 .

[0040] The method comprises the following steps:

[0041] Step 1) Calculate the top shaft oil pressure to ensure that the safety requirements of the unit are met;

[0042] Step 2) Select appropriate positions as connection points, prefabricate bilateral top shaft oil connection devices to realize three-dimensional deep extension of the system;

[0043] Step 3) Conduct a water pressure test on the connection device to ensure the tightness of the shutoff mechanism;

[0044] Step 4) purging the connecting device to ensure the cleanliness of the oil system;

[0045] Step 5) when a single side fails, operating the shut-off switching connecting device to ensure the normal use of the top shaft oil hydraulic system.

[0046] As a preferred solution, the specific step of step 1) of the present application is:

[0047] According to the system parameters of the top shaft oil pump performance and the pipeline resistance, the feasibility of simultaneously supplying two sets of feed water pump turbines by a single set of top shaft oil system is calculated and verified:

[0048]

[0049] In the formula, P is the safety oil pressure of the top shaft oil system, P s is the design outlet pressure of the top shaft oil pump, is the pipeline resistance, and N is the resistance part of the connecting pipeline from the standby system to the expected failure system.

[0050] The specific step of step 2) is:

[0051] A top shaft oil pump and an A steam-driven feed water pump are additionally provided with an oil pipeline, and control oil valves A1, A2 and A3 are additionally provided on the oil pipeline; the A top shaft oil pump is additionally provided with control oil valves A4 and A5 on the single-side self-circulation oil pipeline; a B top shaft oil pump and a B steam-driven feed water pump are additionally provided with an oil pipeline, and control oil valves B1, B2 and B3 are additionally provided on the additionally provided oil pipeline; the B top shaft oil pump is additionally provided with control oil valves B4 and B5 on the single-side self-circulation oil pipeline; the A top shaft oil pump and the B top shaft oil pump are additionally provided with an oil pipeline, and isolation oil valves AB1, AB2, AB3, AB4 and AB5 are additionally provided on the additionally provided oil pipeline.

[0052] The specific step of step 5) is:

[0053] When the A top shaft oil pump operates, if the A top shaft oil pump suddenly fails and stops running,

[0054] ① opening the isolation oil valves AB1-AB5 by interlocking, and opening the interconnection door between the A top shaft oil pump and the B top shaft oil pump; ② closing the control oil valves B1-B5 by interlocking, and closing the control oil door of the B top shaft oil pump;

[0055] ③ opening the B top shaft oil pump by interlocking, and ensuring the normal work of the A steam-driven feed water pump turbine.

[0056] When the B top shaft oil pump operates, if the B top shaft oil pump suddenly fails and stops running,

[0057] ①Interlock open isolation oil valve AB1-AB5, open the interconnection door between A top shaft oil pump and B top shaft oil pump; ②Interlock close control oil valve A1-A5, close the control oil door of A top shaft oil pump;

[0058] ③Interlock open A top shaft oil pump, ensure the normal work of B steam-driven feed water pump turbine.

[0059] As a preferred solution, the application further comprises step 6), during the equipment shutdown maintenance, simulate the accident condition by stopping the single side top shaft oil pump, open the shutdown switching valve, measure the double side top shaft oil pressure, compare and verify with the independent operation of the double side system, and meet the requirements before proceeding with the operation verification test.

[0060] As a preferred solution, the application further comprises step 7), after the unit starts, perform switching test in different load intervals for test verification.

[0061] Specific steps of step 6):

[0062] During the equipment shutdown maintenance, simulate the accident condition by stopping the single side top shaft oil pump, open the shutdown switching valve, measure the double side top shaft oil pressure, compare and verify with the independent operation of the double side system, and meet the requirements before proceeding with the operation verification test.

[0063] Specific steps of step 7):

[0064] After the unit starts, perform switching test in different load intervals, the test load intervals should at least cover the minimum stable operation load, long-term operation load and maximum load of the unit, the entire switching process should take no more than 1 second, and the top shaft oil pressure of the steam-driven feed water pump turbine should be greater than or equal to the safety oil pressure and stable without fluctuation.

[0065] During the equipment shutdown maintenance, simulate the accident condition by stopping the single side top shaft oil pump, open the shutdown switching device, and the double side top shaft oil pressure is the same as when the double side system operates independently.

[0066] After the unit starts, perform switching test in 160MW, 200MW, 350MW, 450MW, 550MW load intervals, the entire switching process is completed within 1 second, the top shaft oil pressure of the steam-driven feed water pump turbine is normal and without fluctuation, and all test data meet the expected results.

[0067] ①Isolation oil valve AB1-AB5 is a newly added system in this modification, and is also the top shaft oil interconnection system of A and B steam-driven feed water pump turbines, and the isolation oil valve AB1-AB5 is the isolation oil door of the top shaft oil interconnection system of A and B steam-driven feed water pump turbines.

[0068] ②Control oil valve A1-A5 is the control oil door of the top shaft oil system of A steam-driven feed water pump turbine.

[0069] ③ Control oil valves B1-B5 are the control throttles for the turbine jacking oil system of the B steam-driven feedwater pump.

[0070] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A three-dimensional depth double linkage reliability optimization method for a hydraulic system of a thermal power generating unit, characterized in that, The method comprises the following steps: Step 1) calculating the top shaft oil pressure to ensure that the safety requirements of the unit are met; Step 2) selecting a suitable position as a connection point, and prefabricating a double-sided top shaft oil connection device to realize the three-dimensional and deep extension of the system; Step 3) performing a water pressure test on the connection device to ensure the tightness of the shutoff mechanism; Step 4) performing a purge on the connection device to ensure the cleanliness of the oil system; Step 5) when a unilateral fault occurs, operating the shutoff switching connection device to ensure that the top shaft oil hydraulic system is normally put into use; The specific steps of step 1) are as follows: According to the system parameters of the top shaft oil pump performance of the feed water pump turbine and the pipeline resistance, the feasibility of simultaneously supplying two sets of feed water pump turbines by a single set of top shaft oil system is calculated and verified: Where: P is the safety oil pressure of the top shaft oil system, P s is the design outlet pressure of the top shaft oil pump, is the pipeline resistance, N is the resistance part of the connecting pipeline from the standby system to the fault system The specific steps of step 2) are as follows: An oil pipeline is additionally arranged between the A top shaft oil pump and the A steam-driven feed water pump, and control oil valves A1, A2 and A3 are additionally arranged on the oil pipeline; control oil valves A4 and A5 are arranged on the unilateral self-circulation oil pipeline of the A top shaft oil pump; an oil pipeline is additionally arranged between the B top shaft oil pump and the B steam-driven feed water pump, and control oil valves B1, B2 and B3 are arranged on the additionally arranged oil pipeline; control oil valves B4 and B5 are additionally arranged on the unilateral self-circulation oil pipeline of the B top shaft oil pump; an oil pipeline is additionally arranged between the A top shaft oil pump and the B top shaft oil pump, and isolation oil valves AB1, AB2, AB3, AB4 and AB5 are arranged on the additionally arranged oil pipeline; The specific steps of step 5) are as follows: When the A top shaft oil pump is running, if the A top shaft oil pump suddenly stops running due to a fault, ① the isolation oil valves AB1-AB5 are opened in interlocking, and the interconnection door between the A top shaft oil pump and the B top shaft oil pump is opened; ② the control oil valves B1-B5 are closed in interlocking, and the control oil door of the B top shaft oil pump is closed; ③ the B top shaft oil pump is opened in interlocking, and the A steam-driven feed water pump turbine is ensured to work normally; When the B top shaft oil pump is running, if the B top shaft oil pump suddenly stops running due to a fault, ① the isolation oil valves AB1-AB5 are opened in interlocking, and the interconnection door between the A top shaft oil pump and the B top shaft oil pump is opened; ② the control oil valves A1-A5 are closed in interlocking, and the control oil door of the A top shaft oil pump is closed; ③ the A top shaft oil pump is opened in interlocking, and the B steam-driven feed water pump turbine is ensured to work normally.

2. The hydraulic system three-dimensional depth double linkage reliability optimization method for a thermal power generating unit according to claim 1, characterized in that, Step 6) is further included, during equipment shutdown and maintenance, an accident condition is simulated by stopping a unilateral top shaft oil pump to perform test verification.

3. The three-dimensional depth double linkage reliability optimization method for a hydraulic system of a thermal power generating unit according to claim 2, characterized in that, The specific steps of step 6) are as follows: During equipment shutdown and maintenance, an accident condition is simulated by stopping a unilateral top shaft oil pump, the shutoff switching valve is opened, the double-sided top shaft oil pressure is measured, and the measurement result is compared and verified with the result when the double-sided system is independently running, and only when the comparison result meets the requirements can the running verification test be performed.

4. The hydraulic system three-dimensional depth double linkage reliability optimization method for a thermal power generating unit according to claim 1, characterized in that, Step 7) is further included, after the unit is started, switching tests are performed in different load intervals for test verification.

5. The three-dimensional depth double linkage reliability optimization method for a hydraulic system of a thermal power generating unit according to claim 4, characterized in that, The specific steps of step 7) are as follows: After the unit starts, switching tests are carried out in different load ranges. The test load range should cover at least the minimum stable operation load, long-term operation load and maximum load of the unit. The time consumption of the whole switching process should be less than 1 second. After the switching is completed, the steam turbine top shaft oil pressure of the steam-driven feed water pump should be greater than or equal to the safety oil pressure and stable without fluctuation.

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