Shutdown protection device of steam turbine security oil system

Abstract

The invention provides a shutdown protection device of a steam turbine security oil system. The shutdown protection device comprises a security oil pipeline, an oil drainage channel and an oil return pipeline which are sequentially communicated, the oil drainage channel comprises a plurality of oil drainage loops connected in parallel, and each oil drainage loop comprises two electromagnetic valves connected in series and the pressure transmitter located on an oil pipeline between the two electromagnetic valves. By arranging a plurality of oil drainage loops connected in parallel, when a single electromagnetic valve of a certain oil drainage loop breaks down, smoothness of the security oil system loop can be guaranteed through other oil drainage loops. When the steam turbine is in a normal operation state, the state of the electromagnetic valve can be tested through the oil pressure reading change of the pressure transmitter, in addition, when the electromagnetic valve breaks down, the electromagnetic valve can be monitored in time, and potential safety hazards are reduced.

Description

Technical Field

[0001] This application belongs to the technical field of steam turbines. Specifically, it relates to a shutdown protection device for the safety oil system of a steam turbine. Background Art

[0002] A steam turbine is an important power generation equipment, and the safety oil system is an important hydraulic medium of the steam turbine. When the steam turbine is in a dangerous working condition, the safety oil is drained through the shutdown protection device to make the steam turbine shut down safely.

[0003] Currently, the shutdown protection device for the safety oil system of a steam turbine uses one or two solenoid valves. When the solenoid valve fails, there is a risk of mis-shutdown and inability to quickly shut down the steam turbine. Moreover, the intact state of the solenoid valve cannot be tested regularly. Relevant specifications require protecting the steam turbine from tripping when the control power is lost. The solenoid valve is in a long-term energized state. After a single solenoid valve loses power or fails, the state of the solenoid valve cannot be effectively monitored, and there are significant potential safety hazards for the safe operation of the steam turbine. Summary of the Invention

[0004] The technical problem solved by this application is: how to avoid the risk of mis-shutdown and inability to quickly shut down the steam turbine caused by the failure of a single solenoid valve and how to effectively monitor the state of the solenoid valve.

[0005] This application provides a shutdown protection device for the safety oil system of a steam turbine. The shutdown protection device includes a safety oil pipeline, an oil drain channel, and an oil return pipeline that are connected in sequence. The oil drain channel includes a number of parallel oil drain circuits. Each oil drain circuit includes two solenoid valves connected in series and the pressure transmitter on the oil pipeline between the two solenoid valves.

[0006] Optionally, the oil drain channel includes:

[0007] The first oil drain circuit, the first oil drain circuit includes a first solenoid valve and a second solenoid valve connected in series and a first pressure transmitter. The first pressure transmitter is installed on the oil pipeline between the first solenoid valve and the second solenoid valve;

[0008] The second oil drain circuit, the second oil drain circuit is parallel to the first oil drain circuit, and the second oil drain circuit includes the second solenoid valve and a third solenoid valve connected in series and a second pressure transmitter. The second pressure transmitter is installed on the oil pipeline between the second solenoid valve and the third solenoid valve;

[0009] The third oil drain circuit, the third oil drain circuit is parallel to the first oil drain circuit, and the third oil drain circuit includes the third solenoid valve and the first solenoid valve connected in series and a third pressure transmitter. The third pressure transmitter is installed on the oil pipeline between the third solenoid valve and the first solenoid valve.

[0010] Optionally, each of the solenoid valves is a single-controlled two-position four-way solenoid valve.

[0011] Optionally, when the steam turbine is in a normal operating state, each solenoid valve is in an energized operating state, and each oil drain circuit is in an open state; when the steam turbine is in an abnormal operating state, each solenoid valve is in a de-energized operating state, and each oil drain circuit is in a conducting state.

[0012] Optionally, when the steam turbine is in a normal operating state and the first solenoid valve is adjusted to a de-energized operating state, the oil pressure reading of the first pressure transmitter increases.

[0013] Optionally, when the steam turbine is in a normal operating state and the second solenoid valve is adjusted to a de-energized operating state, the oil pressure reading of the second pressure transmitter increases.

[0014] Optionally, when the steam turbine is in a normal operating state and the third solenoid valve is adjusted to a de-energized operating state, the oil pressure reading of the third pressure transmitter increases.

[0015] The shutdown protection device for a steam turbine safety oil system provided by this application has the following technical effects:

[0016] By setting multiple parallel oil drain circuits, when a single solenoid valve in a certain oil drain circuit fails, other oil drain circuits can be used to ensure the smoothness of the safety oil system circuit. Under the normal operating state of the steam turbine, the state of the solenoid valve can be tested through the change of the oil pressure reading of the pressure transmitter. In addition, when the solenoid valve fails, it can be detected in time, reducing potential safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the principle of a shutdown protection device for a steam turbine safety oil system according to one or more embodiments. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of this application clearer, the following further elaborates on this application in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0019] Before describing the various embodiments of the present application in detail, the technical concept of the present application will be briefly described first: At present, the shutdown protection device of the steam turbine safety oil system uses one or two solenoid valves. When the solenoid valve fails, there is a risk of mis-shutdown and inability to quickly shut down the steam turbine, and the intact state of the solenoid valve cannot be regularly tested. For this reason, the present application provides a shutdown protection device for the steam turbine safety oil system, in which a number of parallel oil discharge circuits are provided between the safety oil pipeline and the return oil pipeline. Each oil discharge circuit has two solenoid valves and a pressure transmitter. On the one hand, when a single solenoid valve in a certain oil discharge circuit fails, the other oil discharge circuits can be used to ensure the smoothness of the safety oil system circuit. On the other hand, the state of the solenoid valve can be tested by the change in the oil pressure reading of the pressure transmitter. The following describes the specific principle of the shutdown protection device of the steam turbine safety oil system of the present application in combination with more embodiments.

[0020] Specifically, as Figure 1 shown, the shutdown protection device of the steam turbine safety oil system in the first embodiment includes a safety oil pipeline 10, an oil discharge channel 20, and a return oil pipeline 30 that are connected in sequence. The oil discharge channel 20 includes a number of parallel oil discharge circuits. Each oil discharge circuit includes two solenoid valves connected in series and a pressure transmitter on the oil pipeline between the two solenoid valves. Each solenoid valve is a single-control two-position four-way solenoid valve. When the steam turbine is in a normal operating state, each solenoid valve is in an energized operating state, and each oil discharge circuit is in an open state; when the steam turbine is in an abnormal operating state, each solenoid valve is in a de-energized operating state, and each oil discharge circuit is in a conducting state. At this time, the safety oil pipeline 10 and the return oil pipeline 30 are conducted, and the safety oil can be discharged in time.

[0021] In one or more embodiments, the oil discharge channel 20 includes a first oil discharge circuit 21, a second oil discharge circuit 22, and a third oil discharge circuit 23. The second oil discharge circuit 22 is connected in parallel with the first oil discharge circuit 21, and the third oil discharge circuit 23 is connected in parallel with the first oil discharge circuit 21. The first oil discharge circuit 21 includes a first solenoid valve 41 and a second solenoid valve 42 connected in series and a first pressure transmitter 51. The first pressure transmitter 51 is installed on the oil pipeline between the first solenoid valve 41 and the second solenoid valve 42; the second oil discharge circuit 22 includes a second solenoid valve 42 and a third solenoid valve 43 connected in series and a second pressure transmitter 52. The second pressure transmitter 52 is installed on the oil pipeline between the second solenoid valve 42 and the third solenoid valve 43; the third oil discharge circuit 23 includes a third solenoid valve 43 and a first solenoid valve 41 connected in series and a third pressure transmitter 53. The third pressure transmitter 53 is installed on the oil pipeline between the third solenoid valve 43 and the first solenoid valve 41.

[0022] On the one hand, when one of the solenoid valves fails and the other two solenoid valves are working properly, it can ensure that one oil drain circuit is in a conducting state, thus conducting the safety oil pipeline 10 and the oil return pipeline 30. On the other hand, only when the two solenoid valves on each oil drain circuit are de-energized will the oil drain circuit be conducted, avoiding the incorrect conduction of the oil drain circuit due to the misoperation of a certain solenoid valve and improving the reliability. At the same time, by using three solenoid valves to form three parallel oil drain circuits, the number of solenoid valves is minimized to the greatest extent, which is beneficial to reducing costs.

[0023] Exemplarily, when testing the first solenoid valve 41, the steam turbine is in a normal operating state, and the first solenoid valve 41 is adjusted to operate when de-energized. The oil pressure reading of the first pressure transmitter 51 increases. Since the second solenoid valve 42 is energized, the first oil drain circuit 21 is not conducted at this time and is filled with safety oil, and the oil pressure in the oil pipeline increases. If the first oil drain circuit 21 is conducted, the oil pressure will decrease, and it will continue to decrease as the oil volume decreases. When the first oil drain circuit 21 is completely cut off and there is no safety oil, the oil pressure is zero at this time. Therefore, the state of the first solenoid valve 41 can be tested and detected through the change of the oil pressure reading of the first pressure transmitter 51, and at the same time, the conduction condition of the first oil drain circuit 21 is monitored. In addition, in the normal operating state, there is no safety oil in the first oil drain circuit 21. If the oil pressure reading of the first pressure transmitter 51 suddenly increases, it indicates that the first solenoid valve 41 has failed, so as to monitor the state of the first solenoid valve 41 in time.

[0024] Similarly, when testing the second solenoid valve 42, the steam turbine is in a normal operating state, and the second solenoid valve 42 is adjusted to operate when de-energized, and the oil pressure reading of the third pressure transmitter 53 increases. When testing the third solenoid valve 43, the steam turbine is in a normal operating state, and the third solenoid valve 43 is adjusted to operate when de-energized, and the oil pressure reading of the third pressure transmitter 53 increases. The test process and monitoring method of the second solenoid valve 42 and the third solenoid valve 43 can refer to the relevant description of the first solenoid valve 41.

[0025] The shutdown protection device of the steam turbine safety oil system of this embodiment has the following technical effects:

[0026] (1) By setting multiple parallel oil drain circuits, when a single solenoid valve in a certain oil drain circuit fails, the smoothness of the safety oil system circuit can be ensured through other oil drain circuits.

[0027] (2) In the normal operating state of the steam turbine, the state of the solenoid valve can be tested through the change of the oil pressure reading of the pressure transmitter. In addition, when the solenoid valve fails, it can be detected in time.

[0028] The specific embodiments of the present application have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments can be modified and improved without departing from the principles and spirit of the present application as defined by the claims and their equivalents, and such modifications and improvements should also be within the protection scope of the present application.

Claims

1. A shutdown protection device for a steam turbine safety oil system, characterized in that: The shutdown protection device includes a safety oil pipeline, an oil leakage channel and an oil return pipeline which are connected in sequence. The oil leakage channel includes a plurality of parallel oil leakage circuits. Each oil leakage circuit includes two solenoid valves connected in series and the pressure transmitter located on the oil pipeline between the two solenoid valves.

2. The shutdown protection device for the steam turbine safety oil system according to claim 1 is characterized in that: The oil drain channel comprises: A first oil leakage circuit, the first oil leakage circuit comprising a first solenoid valve and a second solenoid valve connected in series and a first pressure transmitter, the first pressure transmitter being installed on an oil pipeline between the first solenoid valve and the second solenoid valve; a second oil leakage circuit, the second oil leakage circuit is connected in parallel with the first oil leakage circuit, and the second oil leakage circuit comprises the second solenoid valve and the third solenoid valve connected in series and a second pressure transmitter, and the second pressure transmitter is installed on the oil pipeline between the second solenoid valve and the third solenoid valve; A third oil leakage circuit, wherein the third oil leakage circuit is connected in parallel with the first oil leakage circuit, and the third oil leakage circuit comprises the third solenoid valve and the first solenoid valve connected in series and a third pressure transmitter, wherein the third pressure transmitter is installed on the oil pipeline between the third solenoid valve and the first solenoid valve.

3. The shutdown protection device for the steam turbine safety oil system according to claim 2 is characterized in that: Each of the solenoid valves is a single-control, two-position, four-way solenoid valve.

4. The shutdown protection device for the steam turbine safety oil system according to claim 2 is characterized in that: When the steam turbine is in normal operation, each solenoid valve is in an energized state and each oil leakage circuit is in a disconnected state; when the steam turbine is in an abnormal operation, each solenoid valve is in a de-energized state and each oil leakage circuit is in a connected state.

5. The shutdown protection device for the steam turbine safety oil system according to claim 4 is characterized in that: When the steam turbine is in a normal operating state and the first solenoid valve is adjusted to a power-off action, the oil pressure reading of the first pressure transmitter increases.

6. The shutdown protection device for the steam turbine safety oil system according to claim 4, characterized in that: When the steam turbine is in a normal operating state and the second solenoid valve is adjusted to a power-off action, the oil pressure reading of the second pressure transmitter increases.

7. The shutdown protection device for the steam turbine safety oil system according to claim 4, characterized in that: When the steam turbine is in a normal operating state and the third solenoid valve is adjusted to a power-off action, the oil pressure reading of the third pressure transmitter increases.

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