Testing device for evaluating overspeed protection system of steam turbine

Abstract

The utility model discloses a testing device for evaluating an overspeed protection system of a steam turbine. The testing device comprises a testing device main body, a speedometer, a rotating speed generation circuit, an event recorder, a first switching value input circuit, an overspeed meter, a switching value output circuit and a second switching value input circuit. According to the utility model, accurate performance evaluation of system overspeed protection functions such as OPC, DEH, ETS and the like is realized. A rotating speed signal of the steam turbine can be simulated, diversified speed change combinations are realized by matching with a speed rising meter, and the use efficiency is improved; recording the action of the overspeed protection device by using a high-resolution SOE (sequence of event), and comparing the action with reference operation for accurate evaluation; the input and output interfaces are suitable for overspeed protection systems of different models and manufacturers, and the universality is wide. The system has comprehensive functions, is easy to use, and provides a feasible means for evaluating the performance of the overspeed protection system for a user.

Description

Technical Field

[0001] The utility model relates to the technical field of evaluation tests for steam turbine overspeed protection systems, and particularly relates to a test device for evaluating steam turbine overspeed protection systems. Background Art

[0002] Modern steam turbines often operate at high speeds in high-temperature and high-pressure environments. When overspeed occurs, they are extremely prone to running away out of control due to the action of centrifugal force, exceeding the mechanical strength of the equipment, resulting in disc deformation, blade fracture, and shaft breakage, causing huge losses to production and personnel. To prevent steam turbine overspeed accidents, steam turbine units are equipped with multiple sets of automatic protection devices, mainly including OPC (Overspeed Protection Control), ETS (Trip Protection System), and mechanical overspeed protection systems. Generally speaking, when the steam turbine speed reaches 103% of the rated speed, the OPC system starts and automatically closes the governing steam valve; when it reaches 110% of the DEH (Digital Electro-Hydraulic Control System), the main steam valve is closed, and a tripping command is sent to the ETS; when the overspeed protection fails to operate or refuses to operate at 110% overspeed, the mechanical overspeed protection system quickly cuts off the steam supply to the steam turbine and shuts it down emergently.

[0003] For steam turbine units, technical means are needed to evaluate the performance and reliability of the overspeed protection functions of systems such as OPC, DEH, and ETS, to ensure that they can operate quickly when they should, and will not malfunction when they should not.

[0004] Currently, there are two directions for simulation tests of overspeed protection systems:

[0005] Using equipment such as function signal generators to generate speed signals, and using signal acquisition cards with event recording functions to record protection actions. This method is mainly used for internal inspection and calibration by system manufacturers. The disadvantage is that the function is relatively simple and the use threshold is high.

[0006] Using a motor to simulate the overspeed protection machine of a steam turbine, with a structure similar to that of a steam turbine, mainly used by end-users for unit-level feasibility verification, focusing on overall evaluation and personnel training. The disadvantage is high cost and low accuracy. Summary of the Invention

[0007] According to an embodiment of the utility model, a test device for evaluating a steam turbine overspeed protection system is provided, including:

[0008] The main body of the test device;

[0009] A speed increasing meter, which is connected to the main body of the test device;

[0010] A speed generating circuit, which is arranged on the main body of the test device and is connected to the speed increasing meter and the steam turbine overspeed protection system to be evaluated;

[0011] An event recorder, which is arranged on the main body of the test device;

[0012] The first digital input circuit is arranged on the main body of the test device and is connected to the event recorder and the steam turbine overspeed protection system to be evaluated;

[0013] The overspeed indicator is arranged on the main body of the test device and is connected to the event recorder;

[0014] The digital output circuit is arranged on the main body of the test device and is connected to the overspeed indicator;

[0015] The second digital input circuit is arranged on the main body of the test device and is connected to the event recorder.

[0016] Furthermore, it further includes:

[0017] The start button switch is arranged on the main body of the test device;

[0018] The bypass self-locking switch is arranged on the main body of the test device.

[0019] Furthermore, it further includes: a communication interface, which is arranged on the main body of the test device.

[0020] Furthermore, it further includes: an indicator light, which is arranged on the main body of the test device.

[0021] Furthermore, it further includes: a power supply module, which is arranged on the main body of the test device.

[0022] Furthermore, it further includes: a trigger unit, which is connected to the overspeed indicator and the event recorder.

[0023] According to an embodiment of the present invention, a test device for evaluating a steam turbine overspeed protection system can accurately evaluate the overspeed protection functions of systems such as OPC, DEH, and ETS. It can simulate the speed signal of the steam turbine, cooperate with the overspeed indicator to achieve diverse rate change combinations, and improve the use efficiency; record the actions of the overspeed protection device with high-resolution SOE and accurately evaluate by comparing with the reference operation; each input and output interface is applicable to overspeed protection systems of different models and manufacturers, with wide versatility. The present invention has comprehensive functions and is easy to use, providing a feasible means for users to evaluate the performance of the overspeed protection system.

[0024] It should be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the claimed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a structural block diagram of a test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention.

[0026] Figure 2 It is a variable speed information block diagram of a speed increasing meter of a test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention.

[0027] Figure 3 It is a recording block diagram of an event recorder of a test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention. Detailed implementation manners

[0028] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and the present invention will be further elaborated.

[0029] First, in combination with Figures 1 - 3 A test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention will be described. It is used for the test of evaluating a steam turbine overspeed protection system and has a wide range of application scenarios.

[0030] As Figure 1 shown, a test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention includes a test device main body 1, a speed increasing meter 2, a speed generating circuit 3, an event recorder 4, a first switch quantity input circuit 5, an overspeed meter 6, a switch quantity output circuit 7, and a second switch quantity input circuit 8.

[0031] Specifically, as Figure 1 shown, the speed increasing meter 2 is connected to the test device main body 1. The speed increasing meter 2 can set multiple groups of variable speed information, and the device executes sequentially to simulate the change process of the steam turbine speed, including speed increasing, speed decreasing, constant speed, rapid variable speed, and slow variable speed, and can be combined arbitrarily to achieve multi-segment continuous variable speed output.

[0032] Specifically, as Figure 1 shown, the speed generating circuit 3 is arranged on the test device main body 1 and is connected to the speed increasing meter 2 and the steam turbine overspeed protection system to be evaluated. The speed generating circuit 3 (PO) provides a speed input signal for the overspeed protection system to be evaluated, which is a square wave signal with adjustable frequency and duty cycle. The frequency range is 0~10KHz, and it can simulate various speeds of the steam turbine, including slow turning, normal operation, overspeed operation, and runaway state. The output interface of the speed generating circuit 3 is a transistor output, which is convenient for users to wire and select a suitable amplitude.

[0033] Specifically, as Figure 1As shown, the event recorder 4 is provided on the test device main body 1. The event recorder 4 (SOE) is used to record internal and external operation records, including protection output events from the overspeed protection system to be evaluated of the object under test, overspeed output actions generated inside the device, and trigger events of the trigger unit 9. The event recording resolution reaches 0.1 ms.

[0034] Specifically, as Figure 1 shown, the first digital input circuit 5 is provided on the test device main body 1 and is connected to the event recorder 4 and the overspeed protection system of the steam turbine to be evaluated. The first digital input circuit 5 is used to receive dry contact digital signals, perform synchronous sampling at a scanning rate of 10 KHz, and record the state changes with the event recorder 4. The first digital input circuit 5 has 4 DIs and is used to detect the operation protection actions of the overspeed protection system to be evaluated.

[0035] Specifically, as Figure 1 shown, the overspeed indicator 6 is provided on the test device main body 1 and is connected to the event recorder 4.

[0036] Specifically, as Figure 1 shown, a test device for evaluating the overspeed protection system of a steam turbine according to an embodiment of the present invention further includes: a trigger unit 9, and the trigger unit 9 is connected to the overspeed indicator 6 and the event recorder 4.

[0037] The overspeed indicator 6 can set 0 to 4 calibration points, and the calibration values are set to be the same as the protection values of the overspeed protection system of the steam turbine to be evaluated. Commonly used values in engineering are 3090 (103%), 3027 (109%), 3030 (110%), which vary for different units. When the speed signal of the speed generating circuit 3 rises to the calibration value, in addition to generating an output action, the overspeed indicator 6 will additionally generate a set of trigger events, which are triggered by the trigger unit 9 and recorded into the event recorder 4. By comparing the record of the trigger events with the record of the output actions of the digital output circuit 7, the delay that may be caused by the output circuit can be compensated. Actually, this value < 0.1 ms and can be ignored during normal use.

[0038] Specifically, as Figure 1 shown, the digital output circuit 7 is provided on the test device main body 1 and is connected to the overspeed indicator 6. The digital output circuit 7 is used to generate a set of overspeed protection actions with extremely small delay as a reference action and a control group. The output interface is a dry contact of a solid-state relay, and the typical action time < 0.1 ms. It cooperates with the overspeed indicator 6. The four DOs respectively correspond to an overspeed value of the overspeed indicator 6. When the speed value of the speed generating circuit 3 ≥ the calibration value, the corresponding digital output is "1", otherwise it is "0", and the delay < 0.1 ms. When the calibration value is the same as the protection value of the overspeed protection system to be measured, a set of reference operations can be generated.

[0039] Specifically, as Figure 1 shown, the second digital input circuit 8 is provided on the main body 1 of the test device and is connected to the event recorder 4. The second digital input circuit 8 receives dry contact digital signals, synchronously samples at a scanning rate of 10KHz and records the state changes with the event recorder 4, and has four DI detection digital output signals generated by the internal overspeed indicator 6. The same access method for internal and external signals cancels out the delay caused by the input circuit.

[0040] Furthermore, as Figure 1 shown, a test device for evaluating a steam turbine overspeed protection system according to an embodiment of the present invention further includes: a start push button switch, a bypass self-locking switch, a communication interface 102, an indicator light 103, and a power supply module 101. The start push button switch is provided on the main body 1 of the test device; the bypass self-locking switch is provided on the main body 1 of the test device. The communication interface 102 is provided on the main body 1 of the test device. The indicator light 103 is provided on the main body 1 of the test device. The power supply module 101 is provided on the main body 1 of the test device.

[0041] The device can be conveniently operated using buttons, including a start push button switch and a bypass self-locking switch. After pressing the start push button, all records in the event recorder 4 are cleared, the time of the event recorder 4 is reset to zero, and the device starts to execute the first set of speed change information of the speed increasing indicator 2. After the test is completed, the rotational speed is retained as the end speed of the last set of speed change information.

[0042] After pressing the bypass self-locking switch, the device enters the bypass mode. At this time, the function of the event recorder 4 is not enabled, and it is used as a rotational speed signal generator and needs to be pressed again to release.

[0043] The device uses 24V DC as the power supply, provides a group of RS485 buses as the communication interface, and the LED indicator light 103 is used to indicate the working state. The soft start of the test can be performed through communication, which has a logical "OR" relationship with the start push button.

[0044] As Figure 2 shown, the speed increasing indicator 2 includes 1 to 16 groups of speed change information. Each group of information includes serial number ID ①, start speed ②, end speed ③, and change time ④. The speed increasing indicator 2 is written through the communication port, and at least one group of speed change information needs to be set in the device.

[0045] ID ① is arranged in sequence starting from 1. When the device is running, it is executed sequentially. When the next ID number is 0 or discontinuous, the speed will no longer change after the current information is executed, and the test ends.

[0046] The starting speed ② can be set in the range of 0 to 10,000 Hz, and the ending speed ③ can be set in the range of 0 to 10,000 Hz. When the ending speed is equal to the starting speed, the rotational speed remains unchanged; when the ending speed is less than the starting speed, the rotational speed decreases. The ending speed of the previous piece of information is the starting speed of the next piece.

[0047] The rotational speed generating circuit 3 uniformly transitions from the starting speed ② to the ending speed ③ according to the change time ④, with a setting range of 1 to 60,000 milliseconds and a resolution of 1 ms, that is, the change rate per millisecond is (ending speed - starting speed) / change time.

[0048] After the test ends, the rotational speed is retained as the ending speed of the last set of valid speed change information.

[0049] As Figure 3 shown, the event recorder 4 (SOE) is used to record internal and external operation records, including protection output events from the object under test, overspeed output actions generated inside the device, and trigger events, with a maximum capacity of 4095 entries.

[0050] The setting range of the valid number ② is 0 to 4095, indicating the number of valid records in the recorder. Writing it as "0" through the communication port clears all records.

[0051] The SOE timer ③ starts accumulating from 0 after the test starts, with a counting range of 0 to 864,000, 1 LSB being 0.1 ms, and it restarts from 0 after reaching the full count.

[0052] Each SOE message includes the status ④, channel code ⑤, and event time ⑥, arranged in the order of occurrence of events from front to back for reading and analysis.

[0053] When the status ④ is "1", it indicates the moment when the switch is closed or software overspeed occurs instantaneously; when it is "0", it indicates the moment when the switch is open or software overspeed does not occur instantaneously, that is, the change process from "not established" to "established" and from "established" to "not established" of the condition is recorded.

[0054] The channel codes ⑤ from 1 to 4 are assigned to the output channels of the overspeed protection system under test, detected by DI; 5 to 8 are assigned to the output actions generated inside the device, detected by DI; 9 to 12 are assigned to the speed change events generated by the overspeed meter 6, triggered by the trigger unit 9.

[0055] The event time ⑥ is the value of the SOE timer at the moment when this event occurs.

[0056] Every 0.1 ms, the switch input channels and the trigger events of the trigger unit 9 are scanned. When a change is found compared to the previous value, the changed information is stored in the event recorder 4①.

[0057] Above, refer to Figures 1 - 3An experimental device for evaluating the overspeed protection system of a steam turbine according to an embodiment of the present utility model is described, which can accurately evaluate the overspeed protection functions of systems such as OPC, DEH, and ETS. It can simulate the rotational speed signal of the steam turbine, cooperate with the speed increasing meter 2 to achieve diverse rate change combinations, and improve the usage efficiency; use high-resolution SOE to record the actions of the overspeed protection device and accurately evaluate by comparing with the reference operation; each input and output interface is applicable to overspeed protection systems of different models and manufacturers, with wide generality. The present utility model has comprehensive functions and is easy to use, providing a feasible means for users to evaluate the performance of the overspeed protection system.

[0058] It should be noted that in this specification, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0059] Although the content of the present utility model has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation to the present utility model. After those skilled in the art have read the above content, various modifications and substitutions to the present utility model will be obvious. Therefore, the protection scope of the present utility model should be defined by the appended claims.

Claims

1. A test device for evaluating a steam turbine overspeed protection system, characterized in that, Comprising: The main body of the test device; A speed increasing meter, which is connected to the main body of the test device; A speed generating circuit, which is arranged on the main body of the test device and is connected to the speed increasing meter and the steam turbine overspeed protection system to be evaluated; An event recorder, which is arranged on the main body of the test device; A first digital input circuit, which is arranged on the main body of the test device and is connected to the event recorder and the steam turbine overspeed protection system to be evaluated; An overspeed meter, which is arranged on the main body of the test device and is connected to the event recorder; A digital output circuit, which is arranged on the main body of the test device and is connected to the overspeed meter; A second digital input circuit, which is arranged on the main body of the test device and is connected to the event recorder.

2. The test device for evaluating the steam turbine overspeed protection system according to claim 1, wherein, It further comprises: A start button switch, which is arranged on the main body of the test device; A bypass self-locking switch, which is arranged on the main body of the test device.

3. The test device for evaluating the steam turbine overspeed protection system according to claim 1, characterized in that, It further comprises: A communication interface, which is arranged on the main body of the test device.

4. The test device for evaluating the overspeed protection system of a steam turbine according to claim 1, characterized in that, It further comprises: An indicator light, which is arranged on the main body of the test device.

5. The test device for evaluating the steam turbine overspeed protection system according to claim 1, characterized in that, It further comprises: A power supply module, which is arranged on the main body of the test device.

6. The test device for evaluating the steam turbine overspeed protection system according to claim 1, characterized in that, It further comprises: A trigger unit, which is connected to the overspeed meter and the event recorder.

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