Flexible starting method for water turbine governor control system

Abstract

The invention relates to the technical field of hydroelectric generating sets, in particular to a water turbine governor control system flexible starting method which comprises the steps that whether the operation state of a hydroelectric generating set is a shutdown standby state or not is judged; if yes, a starting command is sent, and the speed regulator control system receives the starting command; the blades are set to be fully closed at the speed of the first opening degree, and meanwhile the guide blades are set to be opened to the first starting position at the speed of the second opening degree; after set delay, the guide vane is opened to a second starting position at the speed of a second opening degree until the frequency of the hydroelectric generating set reaches the first set frequency range, the guide vane is set to be opened to a third starting position at the speed of the second opening degree, and when it is judged that the frequency of the hydroelectric generating set exceeds the first set frequency range, the guide vane is turned into the no-load state; and the opening degree of the guide vane is adjusted through a PID algorithm until the frequency of the hydroelectric generating set is kept at the second set frequency.

Description

Technical Field

[0001] The invention relates to the technical field of hydroelectric generator sets, and in particular to a flexible starting method for a turbine speed governor control system. Background Art

[0002] The turbine speed governor is one of the most important control devices of the hydro-generator set, which is mainly responsible for the grid connection and regulation functions of the unit. At present, in the current speed governor control system, during the automatic startup of the unit, if the control system frequency measurement channel fails or the frequency measurement element fails, resulting in the loss of all frequencies, the control system cannot normally execute the automatic startup process, and the guide vane may continue to be in the first or second start position, causing the actual frequency of the unit to continue to rise until it is overspeed, which is not conducive to the stable operation of the unit. In addition, during the staged startup process, the guide vane is directly assigned from the first start position to the second start position, and there is a sudden change in the guide vane opening, which may cause a water hammer effect and affect the smoothness of the frequency rise. In addition, during the two-stage startup process, the guide vane is first opened to a larger position, and then closed to near the no-load opening after the unit frequency rises. There is a risk that the unit speed will rise too fast after the guide vane is out of control. Based on this, in response to the above problems, we designed a flexible startup method for the turbine speed governor control system. Summary of the invention

[0003] The object of the present invention is to provide a flexible start-up method for a turbine speed governor control system, which avoids the water hammer effect caused by direct assignment by setting the guide vane opening and the blade opening to change at an appropriate rate during process switching; in addition, the present invention modifies the automatic start-up from a two-stage type to a three-stage type, and the guide vane opening tends to gradually increase, and the speed governor control system can more stably control the unit frequency to rise smoothly, and can effectively avoid the risk of unit overspeed.

[0004] The embodiments of the present invention are implemented by the following technical solutions:

[0005] A method for flexible startup of a turbine speed governor control system, the method comprising the following steps:

[0006] Determine whether the operating state of the hydropower unit is a shutdown standby state;

[0007] If yes, a start command is sent, and the speed governor control system receives the start command;

[0008] The blades are set to be fully closed at a first opening rate, and the guide vanes are set to be opened to a first starting position at a second opening rate;

[0009] After the set delay, the guide vane opens to the second starting position at the second opening rate until the frequency of the hydropower unit reaches the first set frequency range, and the guide vane is set to open to the third starting position at the second opening rate, and it is determined that the frequency of the hydropower unit exceeds the first set frequency range, and the unit enters the no-load state, and the guide vane opening is adjusted by the PID algorithm until the frequency of the hydropower unit remains at the second set frequency.

[0010] Optionally, after the speed regulator control system receives the start-up command, a start-up time limit is also set. During the entire start-up process, it continuously determines whether the frequency of the hydropower unit exceeds the first set frequency range within the start-up time limit. If so, it enters the PID algorithm adjustment stage; if not, the guide vane opening is forcibly adjusted to the no-load position.

[0011] Optionally, after receiving the start-up command, the speed governor control system also includes: starting the safety monitoring point, setting the blades to be fully closed at a first opening rate, and at the same time setting the guide vanes to be opened to a first starting position at a second opening rate. During this process, the operating parameters of the hydropower unit are monitored in real time, and abnormalities are judged based on the operating coefficient threshold of the hydropower unit to execute corresponding emergency measures.

[0012] Optionally, determine whether the operating state of the hydropower unit is a shutdown standby state. If not, identify the current state of the hydropower unit, and execute operation steps of the corresponding state according to the state identification result of the hydropower unit, wherein the current state of the hydropower unit includes: normal operating state, fault state and shutdown state.

[0013] Optionally, if the status identification result of the hydropower unit is a normal operating state, the operation steps are as follows:

[0014] Obtain the operating parameters of the hydropower units based on safety monitoring points;

[0015] Dynamically adjust the load of the hydropower unit according to set conditions, wherein the set conditions include: grid demand and hydrological conditions;

[0016] The guide vane and blade opening of the hydropower unit are dynamically adjusted through the efficiency optimization algorithm to achieve the maximum efficiency point.

[0017] Optionally, if the status identification result of the hydropower unit is a fault state, the operation steps are:

[0018] Conduct fault diagnosis on hydropower units to obtain the fault type and severity of the hydropower units;

[0019] If the fault type of the hydropower unit is determined to be the first fault level, an alarm message is sent and the hydropower unit is repaired online;

[0020] If the fault type of the hydropower unit is determined to be the second fault level, an alarm message is sent and a safety shutdown procedure is executed, wherein the second fault level is greater than the first fault level.

[0021] Optionally, if the status identification result of the hydropower unit is a shutdown state, the operation steps are as follows:

[0022] Evaluate the reasons for shutdown of hydropower units;

[0023] Monitor the shutdown process of the hydropower unit according to the shutdown cause assessment results of the hydropower unit, and ensure that the operating parameters of the hydropower unit are within the set safety range until the hydropower unit completes the shutdown and updates the status of the hydropower unit to the shutdown standby state.

[0024] Optionally, the rate of the first opening is greater than the rate of the second opening.

[0025] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0026] The embodiment of the present invention sets the guide vane opening and the blade opening to change at an appropriate rate during process switching, thereby avoiding the water hammer effect caused by direct assignment; in addition, the present invention modifies the automatic start-up from a two-stage type to a three-stage type, and the guide vane opening tends to gradually increase. The speed governor control system can more stably control the unit frequency to rise smoothly, and can effectively avoid the risk of overspeeding of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a flow chart provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] like Figure 1 As shown, the present invention provides one embodiment: a flexible startup method for a turbine speed governor control system, the method comprising the steps of:

[0030] Determine whether the operating state of the hydropower unit is a shutdown standby state;

[0031] If yes, a start command is sent, and the speed governor control system receives the start command;

[0032] The blades are set to be fully closed at a first opening rate, and the guide vanes are set to be opened to a first starting position at a second opening rate;

[0033] After the set delay, the guide vanes are opened to the second starting position at the second opening rate until the frequency of the hydropower unit reaches the first set frequency range. The guide vanes are set to open to the third starting position at the second opening rate, and it is determined that the frequency of the hydropower unit exceeds the first set frequency range, and the unit enters the no-load state. The guide vane opening is adjusted by the PID algorithm until the frequency of the hydropower unit remains at the second set frequency.

[0034] In this embodiment, the automatic startup method of the speed governor control system designed in this embodiment is a three-stage startup, and the specific steps are as follows: a. Determine that the unit operating state is a shutdown standby state; b. The speed governor control system receives a startup command; c. Close the blades at a rate of 2.5% opening / s, and open the guide vanes to the first starting position: 2% at a rate of 0.5% opening / s; d. After 5s, the guide vanes continue to open to the second starting position at a rate of 0.5% opening / s: the no-load opening corresponding to the current water head; e. When the unit frequency is greater than 15Hz and less than 47.5Hz, the guide vanes continue to open to the third starting position at a rate of 0.5% opening / s: the position of (no-load opening + 5%) corresponding to the current water head; f. When the unit frequency is greater than 47.5Hz, turn the no-load PID to adjust the guide vane opening to stabilize the unit frequency at 50Hz. g. Set the startup time limit to 70s (slightly longer than the normal automatic startup time). When the governor control system cannot enter the no-load state normally, it will enter the no-load state by the startup time limit to avoid overspeeding of the unit. h. During the startup process, continuously determine whether there is a total frequency fault. If so, open the guide vane at a rate of 0.5% opening / s to the no-load opening corresponding to the current water head.

[0035] In this embodiment, after the speed governor control system receives the start-up command, a start-up time limit is also set. During the entire start-up process, it is continuously determined whether the frequency of the hydropower unit exceeds the first set frequency range within the start-up time limit. If so, it enters the PID algorithm adjustment stage; if not, the guide vane opening is forcibly adjusted to the no-load position.

[0036] It can be understood that during the three-stage startup process of this embodiment, the guide vane and paddle blade switch rate can be modified according to actual conditions in order to minimize the water hammer effect. During the three-stage startup process, the guide vane opening and frequency threshold of each process can be appropriately adjusted according to the required automatic startup time and response speed. During the startup process, if there is a total frequency failure, this embodiment will open the guide vane at a rate of 0.5% opening / s to the no-load opening corresponding to the current water head; it can be replaced by fully closing the guide vane and turning the unit to a shutdown state to avoid overspeeding of the unit.

[0037] Specifically, after receiving the start-up command, the speed governor control system also includes: starting the safety monitoring point, setting the blades to be fully closed at a first opening rate, and at the same time setting the guide vanes to be opened to a first starting position at a second opening rate. During this process, the operating parameters of the hydropower unit are monitored in real time, and an abnormality judgment is made based on the operating coefficient threshold of the hydropower unit to execute corresponding emergency measures.

[0038] In further application of this embodiment, it is determined whether the operating state of the hydropower unit is in a shutdown standby state. If not, the current state of the hydropower unit is identified, and based on the state identification result of the hydropower unit, the operation steps of the corresponding state are executed, wherein the current state of the hydropower unit includes: normal operating state, fault state and shutdown state.

[0039] If the status identification result of the hydropower unit is a normal operating state, the operation steps are as follows:

[0040] Obtain the operating parameters of the hydropower units based on safety monitoring points;

[0041] Dynamically adjust the load of the hydropower unit according to set conditions, wherein the set conditions include: grid demand and hydrological conditions;

[0042] The guide vane and blade opening of the hydropower unit are dynamically adjusted through the efficiency optimization algorithm to achieve the maximum efficiency point.

[0043] If the status identification result of the hydropower unit is a fault state, the operation steps are as follows:

[0044] Conduct fault diagnosis on hydropower units to obtain the fault type and severity of the hydropower units;

[0045] If the fault type of the hydropower unit is determined to be the first fault level, an alarm message is sent and the hydropower unit is repaired online;

[0046] If the fault type of the hydropower unit is determined to be the second fault level, an alarm message is sent and a safety shutdown procedure is executed, wherein the second fault level is greater than the first fault level.

[0047] If the status identification result of the hydropower unit is shutdown, the operation steps are as follows:

[0048] Evaluate the reasons for shutdown of hydropower units;

[0049] Monitor the shutdown process of the hydropower unit according to the shutdown cause assessment results of the hydropower unit, and ensure that the operating parameters of the hydropower unit are within the set safety range until the hydropower unit completes the shutdown and updates the status of the hydropower unit to the shutdown standby state.

[0050] During the entire operation of the hydropower unit, it is necessary to monitor safety parameters (bearing temperature, vibration, water pressure, etc.) in real time; at the same time, collect operating data for predictive maintenance and efficiency analysis; dynamically adjust the operating strategy of the hydropower unit according to hydrological conditions and seasonal changes; if the hydropower unit consists of multiple units, it is necessary to continuously optimize the load distribution between units.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flexible startup method for a turbine speed governor control system, characterized in that: The steps of the method include: Determine whether the operating state of the hydropower unit is a shutdown standby state; If yes, a start command is sent, and the speed governor control system receives the start command; The blades are set to be fully closed at a first opening rate, and the guide vanes are set to be opened to a first starting position at a second opening rate; After the set delay, the guide vane opens to the second starting position at the second opening rate until the frequency of the hydropower unit reaches the first set frequency range, and the guide vane is set to open to the third starting position at the second opening rate, and it is determined that the frequency of the hydropower unit exceeds the first set frequency range, and the unit enters the no-load state, and the guide vane opening is adjusted by the PID algorithm until the frequency of the hydropower unit remains at the second set frequency.

2. The flexible startup method of a turbine speed governor control system according to claim 1, characterized in that: After the speed governor control system receives the start-up command, a start-up time limit is also set. During the entire start-up process, it continuously determines whether the frequency of the hydropower unit exceeds the first set frequency range within the start-up time limit. If so, it enters the PID algorithm adjustment stage; if not, it forcibly adjusts the guide vane opening to the no-load position.

3. The flexible startup method of a turbine speed governor control system according to claim 2, characterized in that: After receiving the start-up command, the speed governor control system also includes: starting the safety monitoring point, setting the blades to be fully closed at a first opening rate, and setting the guide vanes to be opened to a first starting position at a second opening rate. During this process, the operating parameters of the hydropower unit are monitored in real time, and an abnormality judgment is made based on the operating coefficient threshold of the hydropower unit to execute corresponding emergency measures.

4. The flexible startup method of a turbine speed governor control system according to claim 3 is characterized in that: Determine whether the operating state of the hydropower unit is a shutdown standby state. If not, identify the current state of the hydropower unit, and execute the operation steps of the corresponding state according to the state identification result of the hydropower unit, wherein the current state of the hydropower unit includes: normal operating state, fault state and shutdown state.

5. The flexible startup method of a turbine speed governor control system according to claim 4, characterized in that: If the status identification result of the hydropower unit is a normal operating state, the operation steps are as follows: Obtain the operating parameters of the hydropower units based on safety monitoring points; Dynamically adjust the load of the hydropower unit according to set conditions, wherein the set conditions include: grid demand and hydrological conditions; The guide vane and blade opening of the hydropower unit are dynamically adjusted through the efficiency optimization algorithm to achieve the maximum efficiency point.

6. The method for flexible startup of a turbine speed governor control system according to claim 5, characterized in that: If the status identification result of the hydropower unit is a fault state, the operation steps are as follows: Conduct fault diagnosis on hydropower units to obtain the fault type and severity of the hydropower units; If the fault type of the hydropower unit is determined to be the first fault level, an alarm message is sent and the hydropower unit is repaired online; If the fault type of the hydropower unit is determined to be the second fault level, an alarm message is sent and a safety shutdown procedure is executed, wherein the second fault level is greater than the first fault level.

7. The flexible startup method of a turbine speed governor control system according to claim 6, characterized in that: If the status identification result of the hydropower unit is shutdown, the operation steps are as follows: Evaluate the reasons for shutdown of hydropower units; Monitor the shutdown process of the hydropower unit according to the shutdown cause assessment results of the hydropower unit, and ensure that the operating parameters of the hydropower unit are within the set safety range until the hydropower unit completes the shutdown and updates the status of the hydropower unit to the shutdown standby state.

8. The flexible startup method of a turbine speed governor control system according to claim 1, characterized in that: The rate of the first opening is greater than the rate of the second opening.

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