Online monitoring system for improving reliability of steam turbine AST shutdown solenoid valve

Abstract

The utility model discloses an on-line monitoring system for improving the reliability of AST shutdown solenoid valves of a steam turbine, the number of the AST shutdown solenoid valves is four, the AST shutdown solenoid valves are divided into two groups, and each group comprises two AST shutdown solenoid valves; during normal operation, the AST shutdown electromagnetic valve is powered on to close the oil discharge port, that is, the safety oil drainage channel is blocked, and therefore safety oil pressure is established; when a fault occurs, an AST shutdown electromagnetic valve loses power, an oil discharge port is opened, safety oil loses pressure, a main throttle valve and a high control valve are closed, and a steam turbine is shut down. By the adoption of the technical scheme, the operation safety and reliability of a unit are enhanced, and after improvement, safe shutdown of a steam turbine is guaranteed under the conditions that a direct-current power source of the electromagnetic valve loses power, a common power grid power source and a UPS (uninterruptible power supply) loses power at the same time, a cable breaks down and the electromagnetic valve breaks down; meanwhile, the functions of preventing misoperation and detecting whether the electromagnetic valve is jammed or not through an online experiment are achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of steam turbine safety control. More specifically, the utility model relates to an online monitoring system for improving the reliability of a steam turbine AST shutdown solenoid valve. BACKGROUND

[0002] As shown in Figure 1 The prior art system is composed of two AST shutdown solenoid valves (AST shutdown solenoid valve 1, AST shutdown solenoid valve 2), two OPC solenoid valves (OPC solenoid valve 5, OPC solenoid valve 6), and corresponding pipelines.

[0003] During normal operation, the AST shutdown solenoid valves 1 and 2 must not be powered on, and the safety oil and OPC oil discharge channels must be closed. The AST shutdown solenoid valves 1 and 2 receive different sources of shutdown signals, and one or both of the AST shutdown solenoid valves 1 and 2 are powered on to act, thereby removing the safety oil pressure and OPC oil. As a result of the loss of safety oil pressure and control oil pressure, the main steam valve and the regulating valve are automatically closed, cutting off the steam turbine and stopping the machine.

[0004] Drawbacks of the prior art:

[0005] The electromagnetic protection device of the prior art uses a powered action. In the field, power failure, cable failure, or coil burnout may occur, and the electromagnetic protection device may not be able to act to close the automatic main steam valve, which may cause the steam turbine to have a speed runaway accident during shutdown.

[0006] Using the keywords "steam turbine; AST; solenoid valve; " and other keywords, a search of existing published technical documents yields the following search results:

[0007] 1. Chinese patent document: "Steam turbine AST solenoid valve fault real-time monitoring alarm device and method", patent (application) number: 201711256394.7; the technical solution described in the document is:

[0008] The steam turbine AST solenoid valve fault real-time monitoring alarm device includes a fault monitoring circuit, which is located at the top of the AST solenoid valve. The fault monitoring circuit is connected to the control system. Creatively, the fault monitoring circuit, which has no connection with the AST solenoid valve, is used to monitor the state of the AST solenoid valve.

[0009] The technical effect described in the document is:

[0010] "Greatly improve the reliability; can indirectly detect the AST solenoid valve through magnetic force in real time without increasing the AST solenoid valve circuit equipment, whether there is a broken wire, burnout failure, etc. Cause power-off opening, and timely repair or replace the AST solenoid valve, to ensure the normal operation of the steam turbine".

[0011] 2. Chinese patent document: "A high-safety protection system for steam turbine generator unit", patent (application) number: 201910195424.0; the technical solution recorded is:

[0012] "A high-safety protection system for steam turbine generator unit, the OPC oil inlet pipe is sequentially provided with an OPC oil pressure gauge, an OPC oil pressure switch, an air guide valve and a first stop valve, and then divided into two branches; the AST oil inlet pipe is sequentially provided with an AST oil pressure gauge, a first AST oil pressure switch, a second AST oil pressure switch and a third AST oil pressure switch, and then divided into two branches; the high-pressure oil pipe is drawn from the outlet of the EH oil pump, and a high-pressure oil stop valve is arranged on the high-pressure oil pipe, and then the high-pressure oil pipe is divided into three branches";

[0013] The technical effects recorded are:

[0014] "The system structure is simple, the operation is convenient, the performance is safe and reliable, the critical shutdown system can be completely isolated, the normal and safe operation of the steam turbine is ensured, so that online simulation test and maintenance of OPC solenoid valve group, AST solenoid valve group and related parts are realized".

[0015] However, the technical solutions recorded in the above technical documents, as well as the existing related technical solutions, have not been able to solve the problems and defects in the prior art that "the electromagnetic protection device cannot act to close the automatic main steam valve" and "the steam turbine appears speed flying accident during shutdown". Practical new type content

[0016] The utility model provides a kind of online monitoring system of AST shutdown solenoid valve, and its purpose is to improve the reliability of steam turbine AST shutdown solenoid valve control.

[0017] In order to achieve the above purpose, the technical scheme adopted by the utility model is:

[0018] The utility model discloses an online monitoring system of improving steam turbine AST shutdown solenoid valve reliability, including AST shutdown solenoid valve, the number of AST shutdown solenoid valve be four, divide into two groups, every group two AST shutdown solenoid valve, in normal operation, AST shutdown solenoid valve power -on closes the oil drain, that is, blocks the safety oil pressure release channel, thereby establishes the safety oil pressure, when the fault occurs, AST shutdown solenoid valve power -off oil drain opens, and the safety oil main pipe releases oil, makes safety oil pressure loss, leads to the main steam door and high -pitch door to close and makes steam turbine shutdown.

[0019] Two groups of AST shutdown solenoid valve are AST first shutdown solenoid valve and AST third shutdown solenoid valve of first group and AST second shutdown solenoid valve and AST fourth shutdown solenoid valve of second group respectively.

[0020] The first group of AST shutdown solenoid valve is connected in parallel with the second group of AST shutdown solenoid valve, the AST first shutdown solenoid valve and the AST third shutdown solenoid valve are connected in series, and the AST second shutdown solenoid valve and the AST fourth shutdown solenoid valve are connected in series.

[0021] Two OPC solenoid valves are arranged on the safety oil main pipe, and are an OPC first solenoid valve and an OPC second solenoid valve.

[0022] A one-way valve is arranged on a pipeline, wherein the OPC first solenoid valve and the OPC second solenoid valve are connected with the safety oil main pipe.

[0023] The online monitoring system is provided with a pressure transmitter, and the pressure transmitter is used to monitor the power-on state of the AST shutdown solenoid valve and an online experimental test function.

[0024] In normal operation, the oil pressure of the pressure transmitter is half of the AST oil pressure.

[0025] The online monitoring system is provided with a pressure switch.

[0026] A field pressure gauge is arranged on the safety oil main pipe.

[0027] In order to realize the same invention purpose as the above technical scheme, the utility model further provides a test method of the online monitoring system of improving steam turbine AST shutdown solenoid valve reliability, and the technical scheme is:

[0028] The online monitoring system tests whether the valve core of the AST shutdown solenoid valve is stuck by making one of the four AST shutdown solenoid valves be powered on alone, and completes the online experimental test function of the solenoid valve.

[0029] The utility model discloses adopt above-mentioned technical scheme, enhance unit operation safety and reliability, improve after whether it is in protection solenoid valve DC power outage, commonly used power grid power and UPS (uninterruptible power supply) power outage simultaneously, cable fault and solenoid valve self -failure condition, can guarantee steam turbine safe shutdown, still have the function such as preventing malfunction and online experiment detection solenoid valve whether jam etc. BRIEF DESCRIPTION OF DRAWINGS

[0030] The contents shown in the drawings and the marks in the drawings are briefly described as follows:

[0031] Figure 1 It is a structural schematic diagram of the prior art;

[0032] Figure 2 It is a structural schematic diagram of the utility model;

[0033] Figure 3 It is a shutdown control logic schematic diagram of the utility model.

[0034] Figure 1 The marks in the drawings are:

[0035] 1, AST shutdown solenoid valve, 2, AST shutdown solenoid valve, 3, OPC solenoid valve, 4, OPC solenoid valve.

[0036] Figure 2 The marks in the drawings are:

[0037] 1, AST first shutdown solenoid valve, 2, AST second shutdown solenoid valve, 3, AST third shutdown solenoid valve, 4, AST fourth shutdown solenoid valve, 5, OPC first solenoid valve, 6, OPC second solenoid valve, 7, pressure switch, 8, field pressure gauge, 9, pressure transmitter, 10, check valve. DETAILED DESCRIPTION

[0038] The specific embodiments of the utility model are further explained in detail below by comparing with the drawings and describing the embodiments, to help the technical personnel in the field to have more complete, accurate and deep understanding of the inventive concept and technical scheme of the utility model.

[0039] As Figure 2 The utility model discloses a structure as shown in the drawings, to improve the online monitoring system of steam turbine AST shutdown solenoid valve reliability, including AST shutdown solenoid valve 1~4.

[0040] In order to solve the problems existing in the prior art and overcome its defects, realize the invention purpose of improving the reliability of steam turbine AST shutdown solenoid valve control, the technical scheme adopted by the utility model is:

[0041] As Figure 2The utility model discloses an online monitoring system for improving the reliability of turbine AST shutdown solenoid valve, the quantity of AST shutdown solenoid valve 1~4 is four, and is divided into two groups, and each group has two AST shutdown solenoid valves;During normal operation, the AST shutdown solenoid valve 1~4 is electrified to close the oil discharge port, that is, to block the safety oil discharge channel, thereby establishing safety oil pressure;When a fault occurs, the AST shutdown solenoid valve 1~4 is de-energized to open the oil discharge port, the safety oil main pipe discharges oil, the safety oil pressure is lost, the main steam valve and the high pitch door are closed, and the turbine is stopped.

[0042] Regarding the turbine AST:

[0043] 1. The working principle of turbine AST (AUTO STOP TRIP):

[0044] Turbine AST is a kind of emergency shutdown protection of turbine, which is realized through AST solenoid valve. When a certain parameter of the turbine reaches the shutdown value, the AST solenoid valve is de-energized to open, and the safety oil is discharged, and the turbine valves are quickly closed. In this way, the turbine can be safely stopped under abnormal conditions, preventing accidents from expanding or equipment damage.

[0045] 2. Application scenario of turbine AST:

[0046] Turbine AST is mainly applied to the emergency shutdown protection of turbine, which can quickly cut off the power source of the turbine when abnormal conditions occur, ensuring the safe shutdown of the turbine. AST is widely used in power, chemical, petroleum, metallurgical and other industries.

[0047] 3. Importance of turbine AST in safe operation of turbine:

[0048] Turbine AST is an important part of emergency shutdown protection of turbine, and is an important protective measure to ensure production safety. It is of great significance to ensure production safety and prevent accidents from expanding or equipment damage. Therefore, the role of turbine AST in the safe operation of turbine cannot be ignored.

[0049] In summary, turbine AST is an important part of emergency shutdown protection of turbine, which is realized through AST solenoid valve. The role of turbine AST in the safe operation of turbine cannot be ignored. AST is widely used in power, chemical, petroleum, metallurgical and other industries, and is an important protective measure to ensure production safety.

[0050] The utility model has the advantages of:

[0051] Enhance the safety and reliability of the unit operation, after the improvement, whether in the protection of electromagnetic valve DC power failure, common power grid power and UPS (uninterruptible power supply) at the same time power failure, cable failure and electromagnetic valve failure, can guarantee the safe shutdown of the turbine.

[0052] The two groups of AST shutdown electromagnetic valves are AST first shutdown electromagnetic valve 1 and AST third shutdown electromagnetic valve 3 of the first group, and AST second shutdown electromagnetic valve 2 and AST fourth shutdown electromagnetic valve 4 of the second group.

[0053] The first group of AST shutdown electromagnetic valves and the second group of AST shutdown electromagnetic valves are connected in parallel; the AST first shutdown electromagnetic valve 1 and the AST third shutdown electromagnetic valve 3 are connected in series; and the AST second shutdown electromagnetic valve 2 and the AST fourth shutdown electromagnetic valve 4 are connected in series.

[0054] The four AST electromagnetic valves are arranged in series and parallel relationship. Only when at least one of the AST first shutdown electromagnetic valve 1 and the AST third shutdown electromagnetic valve 3, and at least one of the AST second shutdown electromagnetic valve 2 and the AST fourth shutdown electromagnetic valve 4, two groups of electromagnetic valves are powered off at the same time, the safety oil pressure will be released and the machine will be stopped; the shutdown logic is as shown in Figure 3 .

[0055] When the ASP oil pressure is equal to the AST oil pressure, at least one of the AST first shutdown electromagnetic valve 1 or the AST third shutdown electromagnetic valve 3 is damaged and loses power;

[0056] When the ASP oil pressure is equal to zero, at least one of the AST second shutdown electromagnetic valve 2 or the AST fourth shutdown electromagnetic valve 4 is damaged and loses power, thereby achieving the goal of online monitoring the working state of the electromagnetic valve.

[0057] Two OPC electromagnetic valves are arranged on the safety oil main pipe, which are OPC first electromagnetic valve 5 and OPC second electromagnetic valve 6.

[0058] A one-way valve 10 is arranged on the pipeline connecting the OPC first electromagnetic valve 5 and the OPC second electromagnetic valve 6 with the safety oil main pipe.

[0059] The turbine OPC (Over speed Protect Controller) is a super-speed protection control. Specifically:

[0060] The initial purpose of the super-speed protection control unit OPC is to prevent the turbine generator set from over-speeding, and to avoid the turbine tripping when the unit speed exceeds 110% of the rated speed. In addition, when part of the load is thrown off due to power system failure, it helps to improve the stability of the power system. This is achieved by relying on the following three functions:

[0061] CIV - Close Interceptor Valves

[0062] LDA - Load Drop Anticipation

[0063] OPC - Overspeed Protection Control

[0064] The online monitoring system is provided with a pressure transmitter 9, which is used to monitor the energized state of the AST shutdown electromagnetic valve and the online experimental test function.

[0065] In normal operation, the oil pressure of the pressure transmitter 9 is half of the AST oil pressure.

[0066] The online monitoring system of the utility model is provided with ASP oil pressure (pressure transmitter 9) to monitor the energized state of the AST electromagnetic valve and the online experimental test function. The ASP oil pressure is half of the AST oil pressure in normal operation.

[0067] The online monitoring system is provided with a pressure switch 7. On the safety oil main pipe, a field pressure gauge 8 is arranged.

[0068] In summary, the online monitoring system of the utility model is composed of four AST shutdown electromagnetic valves (1-4), two OPC electromagnetic valves (5, 6), three pressure switches 7, a field pressure gauge 8, a pressure transmitter 9, two one-way valves 10 and corresponding pipelines, as shown in Figure 2 .

[0069] In order to achieve the same invention purpose as the above technical scheme, the utility model also provides the test method of the online monitoring system for improving the reliability of the AST shutdown electromagnetic valve of the steam turbine, which is described above, and the technical scheme is:

[0070] The online monitoring system tests whether the valve core of the AST shutdown electromagnetic valve is stuck by making one of the four AST shutdown electromagnetic valves 1-4 be energized alone through the ASP oil pressure, so as to complete the electromagnetic valve online experimental test function.

[0071] Through the above method, the utility model also has the functions of preventing misoperation and detecting whether the electromagnetic valve is stuck online.

[0072] The utility model has been described exemplarily above in combination with the drawings, obviously, the utility model specific implementation is not limited by the above-mentioned mode, as long as various non-essential improvements of method concept and technical scheme of adopting the utility model or the utility model concept and technical scheme are directly applied to other occasions without improvement, all are within the protection scope of the utility model.

Claims

1. An online monitoring system for improving the reliability of AST shutdown solenoid valves of a steam turbine, comprising AST shutdown solenoid valves; characterized in that: the number of said AST shutdown solenoid valves is four, which are divided into two groups, each group having two AST shutdown solenoid valves; in normal operation, said AST shutdown solenoid valves are powered to close the oil discharge port, i.e. to block the safety oil discharge channel, thereby establishing safety oil pressure; in case of failure, said AST shutdown solenoid valves lose power to open the oil discharge port, and the safety oil main pipe discharges oil, causing the safety oil to lose pressure, resulting in the closure of the main steam valve and the high pitch valve to stop the steam turbine; said two groups of AST shutdown solenoid valves are respectively AST first shutdown solenoid valve (1) and AST third shutdown solenoid valve (3) of the first group, and AST second shutdown solenoid valve (2) and AST fourth shutdown solenoid valve (4) of the second group; said AST shutdown solenoid valves of the first group are connected in parallel with the AST shutdown solenoid valves of the second group; said AST first shutdown solenoid valve (1) and AST third shutdown solenoid valve (3) are connected in series; said AST second shutdown solenoid valve (2) and AST fourth shutdown solenoid valve (4) are connected in series; two OPC solenoid valves are arranged on said safety oil main pipe, which are respectively OPC first solenoid valve (5) and OPC second solenoid valve (6).

2. The online monitoring system for improving the reliability of the AST shutdown solenoid of a steam turbine according to claim 1, characterized in that: A one-way valve (10) is arranged on the pipeline connecting said OPC first solenoid valve (5) and OPC second solenoid valve (6) with the safety oil main pipe.

3. The online monitoring system for improving the reliability of the AST shutdown solenoid of a steam turbine according to claim 1, characterized in that: The online monitoring system is provided with a pressure transmitter (9); said pressure transmitter (9) is used to monitor the powered state of the AST shutdown solenoid valves and the online experimental test function.

4. The online monitoring system for improving the reliability of the AST shutdown solenoid of a steam turbine according to claim 3, characterized in that: In normal operation, the oil pressure of said pressure transmitter (9) is half of the AST oil pressure.

5. The online monitoring system for improving the reliability of the AST shutdown solenoid of a steam turbine according to claim 3, characterized in that: The online monitoring system is provided with a pressure switch (7).

6. The online monitoring system for improving the reliability of the AST shutdown solenoid of a steam turbine according to claim 1, characterized in that: A field pressure gauge (8) is arranged on said safety oil main pipe.

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