Main steam valve partial stroke activity test system and test method based on throttling mode

Abstract

The present invention discloses a main steam valve partial stroke activity test system based on a throttling mode, comprising a main steam valve and a pressure oil supply pipe, wherein the pressure oil supply pipe is divided into two pipelines, one pipeline is connected with a switch solenoid valve and a servo valve in sequence, and the other pipeline is divided into three pipelines respectively connected with a servo valve, a lower oil chamber of the main steam valve and a full-stroke activity solenoid valve, and the full-stroke activity solenoid valve is also connected with a throttling device through a pipeline, and the outlet of the throttling device is respectively connected with a pressure return oil pipe through a pipeline G8, and the connection between the pipeline G8 and the pressure return oil pipe is respectively connected with a switch solenoid valve and a servo valve through a pipeline, and the servo valve is also connected with the upper oil chamber of the main steam valve through a pipeline. The present invention solves the problem in the prior art that the existing power plant DEH is only designed with a full-stroke test function of the steam valve, but not with a partial-stroke activity function of the steam valve, which seriously affects the safety and reliability of the unit. The present invention also discloses an experimental method for the partial-stroke activity of the main steam valve based on a throttling mode.

Description

Technical Field

[0001] The invention belongs to the field of thermal power technology, and relates to a main steam valve partial stroke activity test system based on a throttling mode. The invention also relates to a main steam valve partial stroke activity test method using the main steam valve partial stroke activity test system. Background Art

[0002] Whether the steam turbine valve can be closed quickly and tightly in an emergency is crucial to the safe operation of the unit. During the operation of the unit, it is necessary to ensure that the valve can always be in a reliable and flexible state. Regular valve activity tests as required are important means to prevent valve jams during continuous operation of the unit, to promptly detect defects in the steam turbine valves, and to prevent serious overspeed accidents in the turbine. In order to ensure the availability and reliability of the main steam valves and regulating valves of the high / low pressure cylinders of the turbine, the valve activity test of the turbine needs to be carried out regularly, and the activity range is 10% to 20%. After investigation, it was found that many thermal power plants currently only conduct full-stroke activity tests of the main steam valves and regulating valves, and do not conduct partial-stroke activity tests of the main steam valves and regulating valves. The main reason is that the DEH of these power plants only designs the full-stroke test function of the valves, and does not design the partial-stroke activity function of the valves, which seriously affects the safety and reliability of the units. Summary of the invention

[0003] The purpose of the present invention is to provide a main steam valve partial stroke activity test system based on throttling mode, which solves the problem that the existing power plant DEH in the prior art is only designed with the full-stroke test function of the steam valve, but not with the partial stroke activity function of the steam valve, which seriously affects the safety and reliability of the unit.

[0004] The technical solution adopted by the present invention is a main steam valve partial stroke activity test system based on a throttling mode, including a main steam valve and a pressure oil supply pipe, the pressure oil supply pipe is divided into two pipelines G1 and G2, the pipeline G1 is connected with a switch solenoid valve and a servo valve in sequence, the pipeline G2 is divided into pipelines G3, G4 and G5, the pipelines G3, G4 and G5 are respectively connected with the servo valve, the lower oil chamber of the main steam valve and the full-stroke activity solenoid valve, the full-stroke activity solenoid valve is also connected with a throttling device through a pipeline G6, the outlet of the throttling device is respectively connected with a pressure return oil pipe through a pipeline G8, the connection between the pipeline G8 and the pressure return oil pipe is also connected with a pipeline G9, the other end of the pipeline G9 is connected with the switch solenoid valve and the servo valve through a pipeline G10 and a pipeline G11 respectively, and the servo valve is also connected with the upper oil chamber of the main steam valve through a pipeline G12.

[0005] The first technical solution of the present invention is also characterized in that:

[0006] The pipeline G12 is also connected to an oil storage chamber.

[0007] A valve is also provided on the pressure oil supply pipe.

[0008] The servo valve is a two-stage electro-hydraulic servo valve.

[0009] The full-stroke movable solenoid valve is a two-position two-way solenoid valve.

[0010] The switch solenoid valve is a two-position two-way solenoid valve.

[0011] The second technical solution adopted by the present invention is a test method for partial stroke activity of the main steam valve based on the throttling mode, using the above-mentioned main steam valve partial stroke activity test system based on the throttling mode, when conducting the partial stroke activity test, specifically:

[0012] When the main steam valve is opened, the full-stroke movable solenoid valve is closed, and the pressure oil supply is divided into two parts through the pressure oil supply pipe through the valve. One part flows to the switch solenoid valve and the servo valve in turn, and the servo valve establishes oil pressure to close the servo valve; the other part of the pressure oil supply flows to the servo valve, the lower oil chamber of the main steam valve and the full-stroke movable solenoid valve respectively. Since the full-stroke movable solenoid valve and the servo valve are in the closed state, this part of the pressure oil supply can only flow to the lower oil chamber of the main steam valve, so that the valve stem of the main steam valve opens upward, and at the same time, the pressure oil in the upper oil chamber of the main steam valve flows to the oil storage chamber;

[0013] When the main steam valve is conducting a partial stroke activity test, open the full-stroke activity solenoid valve, and the pressure oil in the lower oil chamber of the main steam valve and the pressurized oil supply flow to the full-stroke activity solenoid valve, and then flow to the pressurized oil return pipe through the throttling device. The pressure oil in the oil storage chamber flows to the upper oil chamber of the main steam valve to accelerate the closing of the main steam valve.

[0014] The beneficial effects of the present invention are:

[0015] The present invention adds a throttling device to the oil return system of the DEH system of the power plant main steam valve and regulating steam valve full-stroke activity test, so that the flow of the oil return system is three-quarters of the oil return system of the original system without modification, and the oil return time of the oil return system is extended, thereby realizing the partial stroke activity test of the main steam valve and the regulating steam valve, which can effectively prevent the valve from getting stuck during the continuous operation of the unit, timely discover whether there are defects in the turbine valve, prevent the serious overspeed accident of the turbine, and improve the safety, reliability and economy of the unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a main steam valve partial stroke activity test system based on a throttling mode of the present invention.

[0017] In the figure, 1. main steam valve, 2. pressure oil supply pipe, 3. switch solenoid valve, 4. servo valve, 5. lower oil chamber, 6. full-stroke movable solenoid valve, 7. throttling device, 8. pressure oil return pipe, 9. upper oil chamber, 10. oil storage chamber, 11. valve, 12. valve stem. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The present invention is based on the throttling mode of the main steam valve partial stroke activity test system, its structure is as follows Figure 1 As shown, it includes a main steam valve 1 and a pressure oil supply pipe 2. The pressure oil supply pipe 2 is divided into two pipelines G1 and G2. The pipeline G1 is connected with a switch solenoid valve 3 and a servo valve 4 in sequence. The pipeline G2 is divided into pipelines G3, G4 and G5. The pipelines G3, G4 and G5 are respectively connected with the servo valve 4, the lower oil chamber 5 of the main steam valve 1 and the full-stroke movable solenoid valve 6. The full-stroke movable solenoid valve 6 is also connected with a throttling device 7 through a pipeline G6. The outlet of the throttling device 7 is respectively connected with a pressure return oil pipe 8 through a pipeline G8. The connection between the pipeline G8 and the pressure return oil pipe 8 is also connected with a pipeline G9. The other end of the pipeline G9 is connected with the switch solenoid valve 3 and the servo valve 4 through a pipeline G10 and a pipeline G11 respectively. The servo valve 4 is also connected with the upper oil chamber 9 of the main steam valve 1 through a pipeline G12.

[0020] The pipeline G12 is also connected to an oil storage chamber 10 .

[0021] The pressure oil supply pipe 2 is also provided with a valve 11 .

[0022] The servo valve 4 is a two-stage electro-hydraulic servo valve.

[0023] The full-stroke movable solenoid valve 6 is a two-position two-way solenoid valve.

[0024] The switch solenoid valve 3 is a two-position two-way solenoid valve.

[0025] The throttling device of the present invention adopts a standard throttling nozzle.

[0026] The test method of the main steam valve partial stroke activity based on the throttling mode of the present invention adopts the main steam valve partial stroke activity test system based on the throttling mode to test the partial stroke activity, specifically:

[0027] When the main steam valve 1 is opened, the full-stroke movable solenoid valve 6 is closed, and the pressure oil is divided into two parts through the pressure oil supply pipe 2 and the valve 11. One part flows to the switch solenoid valve 3 and the servo valve 4 in sequence, and the servo valve 4 establishes oil pressure to close the servo valve 4; the other part of the pressure oil flows to the servo valve 4, the lower oil chamber 5 of the main steam valve 1 and the full-stroke movable solenoid valve 6 respectively. Since the full-stroke movable solenoid valve 6 and the servo valve 4 are both in the closed state, this part of the pressure oil can only flow to the lower oil chamber 5 of the main steam valve 1, so that the valve stem 12 of the main steam valve is opened upward, and at the same time, the pressure oil in the upper oil chamber 9 of the main steam valve 1 flows to the oil storage chamber 10;

[0028] When the main steam valve 1 is conducting a partial stroke activity test, the full-stroke movable solenoid valve 6 is opened, and the pressure oil in the lower oil chamber 5 of the main steam valve 1 and the pressurized oil supply flow to the full-stroke movable solenoid valve 6, and then flow to the pressurized oil return pipe 8 through the throttling device 7. The pressure oil in the oil storage chamber 10 flows to the upper oil chamber of the main steam valve 1 to accelerate the closing of the main steam valve.

[0029] The throttling device of the present invention can prolong the time for the pressure oil in the lower oil chamber and the pressurized oil supply to flow to the pressurized return oil. The flow rate of the return oil system is three quarters of the return oil system of the original system without modification, thereby extending the oil return time and realizing a partial stroke activity test of 10% to 20% of the valve stroke, so as to timely discover whether the main steam valve is stuck or defective, and effectively improve the safety, reliability and economy of the unit operation.

Claims

1. A test method for the partial stroke activity of the main steam valve based on the throttling mode, characterized in that: A main steam valve partial stroke activity test system based on a throttling method is adopted, comprising a main steam valve (1) and a pressure oil supply pipe (2), wherein the pressure oil supply pipe (2) is divided into two pipelines G1 and G2, wherein the pipeline G1 is connected to a switch electromagnetic valve (3) and a servo valve (4) in sequence, and the pipeline G2 is divided into pipelines G3, G4 and G5, wherein the pipelines G3, G4 and G5 are connected to the servo valve (4), the lower oil chamber (5) of the main steam valve (1) and the full stroke activity electromagnetic valve (6), respectively, and the full stroke activity electromagnetic valve (6) is further connected to a throttling device through a pipeline G6. (7), the outlet of the throttling device (7) is connected to the pressure oil return pipe (8) through the pipeline G8, the connection between the pipeline G8 and the pressure oil return pipe (8) is also connected to the pipeline G9, the other end of the pipeline G9 is connected to the switch solenoid valve (3) and the servo valve (4) through the pipeline G10 and the pipeline G11, the servo valve (4) is also connected to the upper oil chamber (9) of the main steam valve (1) through the pipeline G12; the pipeline G12 is also connected to the oil storage chamber (10); the pressure oil supply pipe (2) is also provided with a valve (11); When conducting a partial trip activity test, specifically: When the main steam valve (1) is opened, the full-stroke movable solenoid valve (6) is closed, and the pressure oil is divided into two parts through the pressure oil supply pipe (2) and the valve (11). One part flows to the switch solenoid valve (3) and the servo valve (4) in sequence. The servo valve (4) builds up oil pressure to close the servo valve (4); the other part of the pressure oil flows to the servo valve (4), the lower oil chamber (5) of the main steam valve (1) and the full-stroke movable solenoid valve (6). Since the full-stroke movable solenoid valve (6) and the servo valve (4) are both in the closed state, this part of the pressure oil can only flow to the lower oil chamber (5) of the main steam valve (1), so that the valve stem (12) of the main steam valve opens upward, and at the same time, the pressure oil in the upper oil chamber (9) of the main steam valve (1) flows to the oil storage chamber (10); When the main steam valve (1) is subjected to a partial stroke movable test, the full stroke movable solenoid valve (6) is opened, and the pressure oil in the lower oil chamber (5) of the main steam valve (1) and the pressure supply oil flow to the full stroke movable solenoid valve (6), and then flow to the pressure return oil pipe (8) through the throttling device (7), and the pressure oil in the oil storage chamber (10) flows to the upper oil chamber of the main steam valve (1) to accelerate the closing of the main steam valve.

2. The test method for the partial stroke activity of the main steam valve based on the throttling mode according to claim 1 is characterized in that: The servo valve (4) is a two-stage electro-hydraulic servo valve.

3. According to the test method for partial stroke activity of the main steam valve based on the throttling mode in claim 1, the full stroke movable solenoid valve (6) is a two-position two-way solenoid valve.

4. According to the test method for the partial stroke activity of the main steam valve based on the throttling mode in claim 1, the switch solenoid valve (3) is a two-position two-way solenoid valve.

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