Frequency modulation control strategy and control system for large bulb tubular unit

Abstract

The invention provides a frequency modulation control strategy and control system for large bulb tubular units, and the control strategy comprises the steps: carrying out the primary frequency modulation of each large bulb tubular unit in a hydraulic power plant when the frequency deviation of a power system is larger than a preset frequency dead zone, and the load change value is smaller than a preset first load change threshold value; when the frequency deviation of the power system is smaller than or equal to a preset frequency dead zone and the load change value is greater than a preset first load change threshold value, performing secondary frequency modulation on each large bulb tubular unit in the hydraulic power plant; and when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is greater than or equal to a preset first load change threshold value, performing primary frequency modulation and secondary frequency modulation on each large bulb tubular unit in the hydraulic power plant based on a power deviation large marking strategy. According to the technical scheme, the unit generation output operation condition can be powerfully improved, and the unit frequency modulation performance is improved.

Description

Technical Field

[0001] The present application relates to the technical field of frequency regulation in hydropower plants, and in particular to a frequency regulation control strategy and control system for large bulb tubular units. Background Art

[0002] Primary frequency regulation is the regulation object of the turbine speed governor. It is one of the most important control means to ensure the stable operation of the hydropower plant units and directly affects the safe and stable operation of the units.

[0003] At present, there are two main control modes for the speed regulator system of hydropower units connected to the grid: power mode and opening mode. The performance of primary frequency regulation will further affect the regulation effect of AGC. For hydropower units, primary frequency regulation refers to the rapid response of the turbine speed regulation system to frequency changes when there is a frequency deviation in the power grid. It is the control of the power grid by the frequency / power characteristics of the hydropower unit regulation system itself, which is achieved by the frequency / power static characteristics of the turbine generator speed regulator through the proportional-integral-differential (PID) regulation characteristics of the speed regulator. Although the differential regulation method of primary frequency regulation cannot completely restore the power grid frequency to the range of (50±0.05HZ), it can significantly reduce the fluctuation amplitude of the power grid frequency. However, the existing technology has not made good improvements to the operating conditions of the unit's power output, resulting in poor frequency regulation performance of the unit. Summary of the invention

[0004] The present application provides a frequency regulation control strategy and control system for a large bulb tubular unit, so as to at least solve the technical problem of poor frequency regulation performance of the unit.

[0005] The first embodiment of the present application proposes a frequency modulation control strategy for a large bulb tubular unit, including:

[0006] Obtain frequency deviation and load change values ​​of the power system;

[0007] When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once;

[0008] When the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, performing secondary frequency modulation on each large bulb tubular unit in the hydropower plant;

[0009] When the frequency deviation of the power system is greater than the preset frequency dead zone and the load change value is greater than or equal to the preset first load change threshold, primary and secondary frequency regulation is performed on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy.

[0010] Preferably, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once, including:

[0011] Obtain the sampling frequency of each large bulb tubular unit in the hydropower plant and the set frequency issued by the corresponding turbine speed control system;

[0012] Determine a first reference value of the guide vane opening of the large bulb tubular unit according to the sampling frequency and the set frequency;

[0013] The large bulb tubular flow unit is adjusted based on the first reference value of the guide vane opening to achieve primary frequency regulation of each large bulb tubular flow unit in the hydropower plant.

[0014] Furthermore, the calculation formula of the first reference value of the guide vane opening of the nth large bulb tubular unit is as follows:

[0015] Y pid,n =C n ×(K p,n +K i,n +K d,n )

[0016] Where Y pid,n is the first reference value of the guide vane opening of the nth large bulb tubular unit, C n is the frequency difference of the nth large bulb tubular unit, K p,n is the proportional gain of the nth large bulb tubular unit, K i,n is the integral gain of the nth large bulb flow unit, K d,n is the differential gain of the nth large bulb tubular unit;

[0017] in, In the formula, f c,n is the set frequency of the nth large bulb tubular unit, f g,n is the sampling frequency of the nth large bulb tubular unit, r is the preset frequency dead zone threshold.

[0018] Furthermore, when the frequency deviation of the power system is less than or equal to a preset frequency dead zone, and the load change value is greater than a preset first load change threshold, before performing secondary frequency modulation on each large bulb tubular unit in the hydropower plant, the method further includes:

[0019] Receive the given power sent by the monitoring system;

[0020] Determine whether the absolute value of the difference between the given power and the given feedback value of the speed regulator power corresponding to the large-scale bulb cross-flow type unit is less than or equal to a preset first power threshold; if so, determine that the given power issued by the monitoring system is correct; if correct, determine the second reference value of the guide vane opening of each large-scale bulb cross-flow type unit corresponding to the secondary frequency modulation according to the total given power and the total actual power; otherwise, determine that the given power issued by the monitoring system is wrong.

[0021] Furthermore, when the frequency deviation of the power system is less than or equal to a preset frequency dead zone, and the load change value is greater than a preset first load change threshold, the large bulb tubular units in the hydropower plant are subjected to secondary frequency modulation, including:

[0022] respectively determining the absolute value of the difference between the given power and the actual power generated by the large bulb tubular unit;

[0023] When the absolute value of the difference is greater than or equal to a preset first power threshold, a second reference value of the guide vane opening is calculated using a fast adjustment module;

[0024] When the absolute value of the difference is less than a preset first power threshold, a power regulation PID module is used to calculate a second reference value of the guide vane opening.

[0025] Furthermore, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, each large bulb tubular unit in the hydropower plant is subjected to primary and secondary frequency regulation based on a large power deviation marking strategy, including:

[0026] Step F1: Determine whether the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant is greater than a preset frequency dead zone threshold, if so, proceed to step F2, otherwise do not execute;

[0027] Step F2: determine whether the load change value is caused by the change in water head, if so, start frequency modulation, otherwise start small load distribution for each large bulb tubular unit in the hydropower plant;

[0028] Step F3: obtaining the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant after starting the first frequency modulation or starting the first small load distribution, and determining the range to which the difference belongs. When the difference belongs to the preset frequency dead zone, the secondary frequency modulation is not performed. When the difference is equal to the preset first power threshold, the load is manually distributed to each large bulb flow-through unit through the monitoring system. When the difference is greater than the preset second power threshold, the secondary frequency modulation is started to distribute the load equally to each large bulb flow-through unit.

[0029] The large power deviation marking strategy includes: step F1 and step F2.

[0030] Furthermore, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, the primary and secondary frequency regulation of each large bulb tubular unit in the hydropower plant based on the large power deviation marking strategy also includes:

[0031] When the action directions required by the secondary frequency modulation and the primary frequency modulation action instructions are the same, the two instructions are superimposed and processed to issue a comprehensive instruction to the large bulb tubular unit;

[0032] When the action directions required by the secondary frequency regulation and primary frequency regulation action instructions are different, if the power grid requires the plant to give priority to ensuring the unit output, then choose to lock the primary frequency regulation action instruction. If the power grid requires the plant to give priority to responding to the grid frequency regulation needs, then choose to lock the secondary frequency regulation action instruction.

[0033] The second embodiment of the present application provides a frequency modulation control system for a large bulb tubular unit, comprising:

[0034] An acquisition module, used for acquiring frequency deviation and load change values ​​of the power system;

[0035] A first frequency modulation module, configured to perform a frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is less than a preset first load change threshold;

[0036] A second frequency modulation module is used to perform secondary frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is less than or equal to a preset frequency dead zone and the load change value is greater than a preset first load change threshold;

[0037] The third frequency regulation module is used to perform primary and secondary frequency regulation on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is greater than or equal to a preset first load change threshold.

[0038] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.

[0039] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.

[0040] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0041] The present application proposes a frequency regulation control strategy and control system for large bulb flow-through units, wherein the control strategy includes: obtaining the frequency deviation and load change value of the power system; when the frequency deviation of the power system is greater than the preset frequency dead zone, and the load change value is less than the preset first load change threshold, performing a primary frequency regulation on each large bulb flow-through unit in the hydropower plant; when the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, performing a secondary frequency regulation on each large bulb flow-through unit in the hydropower plant; when the frequency deviation of the power system is greater than the preset frequency dead zone, and the load change value is greater than or equal to the preset first load change threshold, performing a primary and secondary frequency regulation on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy. The technical solution proposed in the present application can effectively improve the operating conditions of the unit's power generation output and enhance the unit's frequency regulation performance.

[0042] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0044] Figure 1 A flow chart of a frequency modulation control strategy for a large bulb tubular unit provided according to an embodiment of the present application;

[0045] Figure 2 A flow chart of secondary frequency modulation according to an embodiment of the present application;

[0046] Figure 3 A flow chart of a coordinated control strategy for secondary frequency modulation and primary frequency modulation provided according to an embodiment of the present application;

[0047] Figure 4 A schematic diagram of a 50% load primary frequency modulation function provided according to an embodiment of the present application;

[0048] Figure 5 A schematic diagram of a frequency regulation function after 50% load adjustment is completed and exited according to an embodiment of the present application;

[0049] Figure 6 A schematic diagram of a frequency modulation function in which 90% of the load is put into operation once according to an embodiment of the present application;

[0050] Figure 7 A schematic diagram of a frequency regulation function exiting after 90% load adjustment is completed according to an embodiment of the present application;

[0051] Figure 8 A schematic diagram of a 0.2 Hz up-disturbance waveform provided according to an embodiment of the present application;

[0052] Fig. 9 A schematic diagram of a 0.2 Hz down-disturbance waveform provided according to an embodiment of the present application;

[0053] Fig.10 A schematic diagram of a frequency regulation function when a speed regulator is put into operation for load adjustment according to an embodiment of the present application;

[0054] Fig.11 The present invention is a structural diagram of a frequency modulation control system for a large bulb cross-flow unit according to one embodiment of the present application. DETAILED DESCRIPTION

[0055] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0056] The present application proposes a frequency regulation control strategy and control system for large bulb flow-through units, wherein the control strategy includes: obtaining the frequency deviation and load change value of the power system; when the frequency deviation of the power system is greater than the preset frequency dead zone, and the load change value is less than the preset first load change threshold, performing a primary frequency regulation on each large bulb flow-through unit in the hydropower plant; when the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, performing a secondary frequency regulation on each large bulb flow-through unit in the hydropower plant; when the frequency deviation of the power system is greater than the preset frequency dead zone, and the load change value is greater than or equal to the preset first load change threshold, performing a primary and secondary frequency regulation on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy. The technical solution proposed in the present application can effectively improve the operating conditions of the unit's power generation output and enhance the unit's frequency regulation performance.

[0057] The following describes a frequency modulation control strategy and control system for a large bulb cross-flow unit according to an embodiment of the present application with reference to the accompanying drawings.

[0058] Embodiment 1

[0059] Figure 1FIG. 1 is a flow chart of a frequency modulation control strategy for a large bulb tubular unit according to an embodiment of the present application. Figure 1 As shown, the control strategy includes:

[0060] Step 1: Obtain the frequency deviation and load change value of the power system;

[0061] Step 2: 1) When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once;

[0062] In the embodiment of the present disclosure, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once, including:

[0063] 2.1.1: Obtain the sampling frequency of each large bulb tubular unit in the hydropower plant and the set frequency issued by the corresponding turbine speed control system;

[0064] 2.1.2: Determine a first reference value of the guide vane opening of the large bulb tubular unit according to the sampling frequency and the set frequency;

[0065] 2.1.3: The large bulb tubular unit is adjusted based on the first reference value of the guide vane opening to achieve primary frequency regulation of each large bulb tubular unit in the hydropower plant.

[0066] The calculation formula for the first reference value of the guide vane opening of the nth large bulb tubular unit is as follows:

[0067] Y pid,n =C n ×(K p,n +K i,n +K d,n )

[0068] Where Y pid,n is the first reference value of the guide vane opening of the nth large bulb tubular unit, C n is the frequency difference of the nth large bulb tubular unit, K p,n is the proportional gain of the nth large bulb tubular unit, K i,n is the integral gain of the nth large bulb flow unit, K d,n is the differential gain of the nth large bulb tubular unit, wherein the proportional gain may be 1.7; wherein, In the formula, f c,n is the set frequency of the nth large bulb tubular unit, f g,nis the sampling frequency of the nth large bulb tubular unit, r is the preset frequency dead zone threshold.

[0069] It should be noted that the sampling frequency f g,n With the set frequency f c,n Compare and calculate the frequency deviation. When the frequency deviation is less than the preset frequency dead zone threshold, no adjustment is made. When the frequency deviation > the preset frequency dead zone threshold, the frequency difference is calculated.

[0070] Substitute the frequency difference into the formula Y pid,n =C n ×(K p,n +K i,n +K d,n ), a first reference value of the guide vane opening is calculated, and the first reference value of the guide vane opening is sent to the governor actuator to control the guide vane opening.

[0071] 2) When the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, secondary frequency modulation is performed on each large bulb tubular unit in the hydropower plant;

[0072] In the embodiment of the present disclosure, when the frequency deviation of the power system is less than or equal to a preset frequency dead zone, and the load change value is greater than a preset first load change threshold, before performing secondary frequency modulation on each large bulb tubular unit in the hydropower plant, the method further includes:

[0073] Receive the given power sent by the monitoring system;

[0074] Determine whether the absolute value of the difference between the given power and the given feedback value of the speed regulator power corresponding to the large-scale bulb cross-flow type unit is less than or equal to a preset first power threshold; if so, determine that the given power issued by the monitoring system is correct; if correct, determine the second reference value of the guide vane opening of each large-scale bulb cross-flow type unit corresponding to the secondary frequency modulation according to the total given power and the total actual power; otherwise, determine that the given power issued by the monitoring system is wrong.

[0075] It should be noted that the preset first power threshold may be 5 MW.

[0076] Furthermore, when the frequency deviation of the power system is less than or equal to a preset frequency dead zone, and the load change value is greater than a preset first load change threshold, the large bulb tubular units in the hydropower plant are subjected to secondary frequency modulation, including:

[0077] respectively determining the absolute value of the difference between the given power and the actual power generated by the large bulb tubular unit;

[0078] When the absolute value of the difference is greater than or equal to a preset first power threshold, a second reference value of the guide vane opening is calculated using a fast adjustment module;

[0079] When the absolute value of the difference is less than a preset first power threshold, a power regulation PID module is used to calculate a second reference value of the guide vane opening.

[0080] It should be noted that if Figure 2 As shown, the monitoring system AGC sends the power given Pc to the speed regulator in the form of communication quantity (main) and analog quantity. At the same time, the monitoring system judges the accuracy of the sent power given Pc. When the deviation between the power given Pc and the speed regulator power given feedback value Pf is between 0-5MW, it is judged that the instruction is correct. If the instruction verification is correct, the monitoring sends the execution command to the speed regulator electrical control cabinet PLC. The PLC compares the power given Pc with the unit power sampling Pg and calculates the power deviation. In order to adjust the load, it needs to be processed through the preset deviation limit and power dead zone parameters. Only when the power deviation is greater than the power dead zone, load adjustment, that is, secondary frequency regulation, will be performed.

[0081] A segmented and graded regulation scheme is proposed for secondary frequency regulation: a two-stage graded regulation is carried out with a power deviation of 50MW as the dividing point.

[0082] 1) When the power deviation is greater than or equal to 50MW, the fast adjustment module is used to calculate the opening value Pgv, and send it to the governor actuator in the form of opening to control the opening and closing of the turbine guide vanes, thereby achieving rapid adjustment of the unit output power.

[0083] 2) When the power deviation is less than 50MW, we use the power regulation PID module to calculate the opening value Pgv, and send it to the governor sub-loop actuator in the form of Pgv to control the opening and closing of the turbine guide vanes, thereby achieving precise regulation of the unit output power.

[0084] 3) When the unit power deviation is adjusted to the power dead zone, no further adjustment will be made to meet the system's requirements for the speed regulator regulation quality.

[0085] Through this segmented adjustment scheme, we can achieve precise control of the unit output power, thereby ensuring the stability and safety of the power system. The principle of the fast adjustment module is shown in Formula P gv =P gv1 ±T rp , where: Trp is the step size of increase and decrease, the step size is proportional to the power deviation, P gv1 is the opening value of the previous step length.

[0086] Power regulation PID module: It is conventional PID regulation, but different from the primary frequency regulation PID parameters, it has independent adjustable PID parameters. The parameter selection is obtained through on-site power deviation step test.

[0087] 3) When the frequency deviation of the power system is greater than the preset frequency dead zone, and the load change value is greater than or equal to the preset first load change threshold, primary and secondary frequency regulation is performed on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy.

[0088] In the embodiment of the present disclosure, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, each large bulb tubular unit in the hydropower plant is subjected to primary and secondary frequency regulation based on a large power deviation marking strategy, including:

[0089] Step F1: Determine whether the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant is greater than a preset frequency dead zone threshold, if so, proceed to step F2, otherwise do not execute;

[0090] Step F2: determine whether the load change value is caused by the change in water head, if so, start frequency modulation, otherwise start small load distribution for each large bulb tubular unit in the hydropower plant;

[0091] Step F3: obtaining the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant after starting the first frequency modulation or starting the first small load distribution, and determining the range to which the difference belongs. When the difference belongs to the preset frequency dead zone, the secondary frequency modulation is not performed. When the difference is equal to the preset first power threshold, the load is manually distributed to each large bulb flow-through unit through the monitoring system. When the difference is greater than the preset second power threshold, the secondary frequency modulation is started to distribute the load equally to each large bulb flow-through unit.

[0092] The power deviation large marking strategy includes: step F1 and step F2;

[0093] The preset second power threshold may be 10 MW.

[0094] It should be noted that if Figure 3 As shown, when performing primary frequency modulation and secondary frequency modulation, it includes: 1. a large power deviation marking strategy, and 2. an AGC and primary frequency modulation coordination strategy.

[0095] The power deviation large marking strategy includes:

[0096] 1) When the difference between the active power setting value and the actual value is too large, a mark is added: when the difference between the total active power setting value and the actual value of the whole plant is greater than the set multiple of the dead zone of the active power adjustment of the whole plant, a small load distribution is started to reduce the difference between the total active power setting value and the actual value of the whole plant.

[0097] The set multiple of the dead zone for active power adjustment of the whole plant can be 0.5 times 5MW.

[0098] 2) If the difference between the actual power generation of the units not participating in AGC and the set power value exceeds the set multiple (0.5 times) of the dead zone of the AGC setting for the whole plant in two consecutive calculation cycles, the AGC load adjustment distribution will be reopened. This strategy will only be triggered when the load deviation is caused by the units not participating in AGC. This method can effectively solve the problem of AGC load readjustment caused by primary frequency adjustment.

[0099] The AGC and primary frequency modulation coordination strategy includes:

[0100] 1) When the load change of the unit without AGC is caused by the change of water head or other reasons, the secondary frequency regulation (AGC) process will no longer be entered, and the primary frequency regulation action will be the main action; after the primary frequency regulation is completed, the AGC will continue to work and control the load of the whole plant.

[0101] 2) After the unit executes the active load regulation instruction, the plant station comprehensively judges whether the unit's active load regulation instruction has been executed based on factors such as the unit's active load regulation rate, regulation accuracy, and primary equipment operation status. The time constant T is comprehensively calculated based on factors such as the peak-shaving and frequency-regulating role the plant station plays in the power grid and the primary equipment action response. After the unit's active load regulation instruction is executed, a frequency regulation action instruction is executed again after a delay of time constant T.

[0102] 3) Introduce the two input signals of primary frequency modulation, "input" and "action", into the AGC configuration, and add the following logic strategies:

[0103] ① Secondary frequency regulation judgment logic: When the total active power setting value of the whole plant changes or the active power setting value of the non-AGC unit changes, the secondary frequency regulation state is entered. The whole plant setting value and the actual value are within the dead zone of the whole plant adjustment and the single machine active power distribution value and the actual value are within the dead zone of the unit active power adjustment. At the same time, no unit is in the process of crossing the vibration zone. It is judged that the secondary frequency regulation process is over. When the unit or the whole plant active power cannot be adjusted to the dead zone, it will cause the secondary frequency regulation process to be unable to end for a long time. At this time, if the secondary frequency regulation process is entered after the set time and the unit is not in the process of step-by-step crossing the vibration zone, the secondary frequency regulation process is over.

[0104] ② The coordinated control relationship between primary frequency regulation and AGC (secondary frequency regulation): When the whole plant is in the AGC (secondary frequency regulation) process, the load distribution of the unit does not take into account the impact of primary frequency regulation. When the AGC (secondary frequency regulation) process of the whole plant is over, AGC will still calculate the parameters of the whole plant and the unit, but will no longer distribute the load to the unit. This means that all load adjustments will be made by primary frequency regulation. After the primary frequency regulation process is over, AGC will continue to manage the load of the whole plant. The advantage of this is that the primary frequency regulation and AGC (secondary frequency regulation) can be coordinated, making the operation of the entire system more stable, while also ensuring the fairness of load distribution.

[0105] Furthermore, when the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, the primary and secondary frequency regulation of each large bulb tubular unit in the hydropower plant based on the large power deviation marking strategy also includes:

[0106] When the action directions required by the secondary frequency modulation and the primary frequency modulation action instructions are the same, the two instructions are superimposed and processed to issue a comprehensive instruction to the large bulb tubular unit;

[0107] When the action directions required by the secondary frequency regulation and primary frequency regulation action instructions are different, if the power grid requires the plant to give priority to ensuring the unit output, then choose to lock the primary frequency regulation action instruction. If the power grid requires the plant to give priority to responding to the grid frequency regulation needs, then choose to lock the secondary frequency regulation action instruction.

[0108] It should be noted that: ① when the active load regulation direction of the unit is the same as the action direction required by the primary frequency regulation action instruction, the two instructions are superimposed and processed, and a comprehensive instruction is issued to the unit to enable it to simultaneously meet the requirements of active load regulation and primary frequency regulation action.

[0109] ② When the active load regulation of the unit is in a different direction from the action direction required by the primary frequency regulation action instruction, according to the role of the power grid node where the plant is located, if the power grid requires the plant to give priority to ensuring the unit output, then choose to lock the primary frequency regulation action instruction; if the power grid requires the plant to give priority to responding to the needs of power grid frequency regulation, then choose to lock the active load regulation instruction of the unit.

[0110] In the power system, frequency regulation is very important, which can ensure that the frequency of the power system is within a reasonable range. The coordination between primary frequency regulation and AGC (secondary frequency regulation) is even more important. Only when they are coordinated can the entire power system operate stably.

[0111] The frequency modulation control strategy for a large bulb tubular unit proposed in this embodiment is analyzed with examples below.

[0112] 1. Example parameter description

[0113] The hydropower station is equipped with 8 bulb-type cross-flow generator sets with a single unit capacity of 50MW, with a total installed capacity of 400MW. The generators are jointly manufactured by Harbin Electric Motor Factory and Alstom. From upstream to downstream, the generator system, combined bearings, and water-guided bearings are arranged in sequence. The generator cooling method adopts full air cooling, and the center point grounding method is grounding with a grounding transformer. Its main parameters are shown in Tables 1 and 2 below:

[0114] Table 1 Generator technical parameters

[0115]

[0116] Table 2 PIDD parameters of primary frequency regulation of speed regulator control system

[0117]

[0118] 2. Primary frequency modulation function activation and deactivation test

[0119] The frequency regulation function was tested at 50% load and 90% load respectively, and the following results were obtained: Figure 4 , Figure 5 , Figure 6 , Figure 7 Waveforms, data in Table 3 and Table 4:

[0120] Table 350% load switching frequency regulation test data

[0121]

[0122] Table 4 90% load switching frequency regulation test data

[0123]

[0124] According to the test results, when the speed governor is put into the primary frequency regulation function, the speed governor performs the primary frequency regulation according to the machine frequency. When the primary frequency regulation is activated, the opening and load change significantly. It can be seen that under the primary frequency regulation strategy proposed in this paper, the unit speed governor can quickly respond to the change of grid load and participate in the primary frequency regulation of the grid.

[0125] However, since the remaining power station units in the weak foreign power grid were not put into primary frequency regulation and only the test units participated in primary frequency regulation, the power regulation of a single unit could not have a substantial impact on the frequency of the entire power grid, so the frequency change was not obvious.

[0126] 3. Speed ​​​​regulator frequency disturbance analysis

[0127] The frequency 50Hz is disturbed to 50.2Hz and then restored to 50Hz to obtain the following Figure 8The up-disturbed 0.2Hz waveform shown;

[0128] The frequency is disturbed from 50Hz to 49.8Hz and then restored to 50Hz to obtain the following Fig. 9 The down-disturbed 0.2Hz waveform shown;

[0129] Test results

[0130] Table 5 Disturbance test data of speed governor tester

[0131]

[0132] Table 6 Technical requirements control test data

[0133]

[0134] Based on Table 5 and Table 6, it can be obtained that when the unit frequency is disturbed from 50Hz to 50.2Hz, after the 300s primary frequency modulation function adjustment, the deviation from the theoretical opening is 0.61%; when the unit frequency is disturbed from 50Hz to 49.8Hz, after the 300s primary frequency modulation function adjustment, the deviation from the theoretical opening is 0.26%. The unit primary frequency modulation response time meets the 3s requirement.

[0135] 4. The speed regulator load is adjusted when the frequency modulation function is activated

[0136] After the unit is running stably, the upper computer increases the load. During the process of monitoring and issuing commands to adjust the load, the speed governor is disturbed by 0.2Hz. In the model, the guide vane opening output command is the comprehensive result of the monitoring opening superimposed on the frequency adjustment calculation, such as Fig.10 shown.

[0137] ① The upper computer increases the load by 5MW, that is, the upper computer issues an order to adjust from 45MW to 50MW, the guide vane opening increases, and the 0s guide vane starts to move.

[0138] ② After about 5 seconds, the speed governor integrated tester was operated to generate frequency, with an upper disturbance of 0.2Hz. Because the primary frequency modulation function was put into use, the guide vane opening decreased when the frequency was disturbed. At this time, the primary frequency modulation action caused the increasing opening to suddenly decrease.

[0139] ③ As the load is adjusted upward to the regulation dead zone, the guide vane opening continues to increase.

[0140] ④ The monitoring ends when the load is adjusted to the range of 0<<0.5MW, but the frequency difference disturbance exists and the guide vane opening required for the first frequency modulation action has not reached the target value, and the guide vane opening continues to decrease. Therefore, a peak is seen in the guide vane opening curve at 255s, as shown in the red box.

[0141] ⑤ The frequency input disturbance signal is restored, the frequency input is 50Hz, and the guide vane opening is set to increase. It can be seen that the guide vane curve increases in the opening direction.

[0142] According to the test data, the change in the opening of the governor guide vane during the primary frequency regulation and the change in the opening during the governor load adjustment are processed in a superimposed manner, which is consistent with the program model and operation logic.

[0143] The frequency regulation strategy proposed in this embodiment improves the problem of low frequency regulation rate in a weak power grid environment of a hydropower station. The optimized comprehensive frequency regulation performance indicators of the units are compared and verified experimentally. The comprehensive frequency regulation performance indicators are greatly improved, which effectively improves the frequency regulation rate of the speed regulator system.

[0144] In summary, the frequency regulation control strategy for a large bulb tubular unit proposed in this embodiment can effectively improve the unit's power generation output operating conditions and enhance the unit's frequency regulation performance.

[0145] Embodiment 2

[0146] Fig.11 FIG. 1 is a structural diagram of a frequency modulation control system for a large bulb tubular unit according to an embodiment of the present application. Fig.11 As shown, the system comprises:

[0147] An acquisition module 100 is used to acquire a frequency deviation and a load change value of a power system;

[0148] The first frequency modulation module 200 is used to perform a frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is less than a preset first load change threshold;

[0149] The second frequency modulation module 300 is used to perform secondary frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is less than or equal to a preset frequency dead zone and the load change value is greater than a preset first load change threshold;

[0150] The third frequency regulation module 400 is used to perform primary and secondary frequency regulation on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is greater than or equal to a preset first load change threshold.

[0151] In the embodiment of the present disclosure, the acquisition module 100 is further used for:

[0152] Obtain the sampling frequency of each large bulb tubular unit in the hydropower plant and the set frequency issued by the corresponding turbine speed control system;

[0153] Determine a first reference value of the guide vane opening of the large bulb tubular unit according to the sampling frequency and the set frequency;

[0154] The large bulb tubular flow unit is adjusted based on the first reference value of the guide vane opening to achieve primary frequency regulation of each large bulb tubular flow unit in the hydropower plant.

[0155] The calculation formula of the first reference value of the guide vane opening of the nth large bulb tubular unit is as follows:

[0156] Y pid,n =C n ×(K p,n +K i,n +K d,n )

[0157] Where Y pid,n is the first reference value of the guide vane opening of the nth large bulb tubular unit, C n is the frequency difference of the nth large bulb tubular unit, K p,n is the proportional gain of the nth large bulb tubular unit, K i,n is the integral gain of the nth large bulb flow unit, K d,n is the differential gain of the nth large bulb tubular unit;

[0158] in, In the formula, f c,n is the set frequency of the nth large bulb tubular unit, f g,n is the sampling frequency of the nth large bulb tubular unit, r is the preset frequency dead zone threshold.

[0159] In the embodiment of the present disclosure, the second frequency modulation module 300 is further used for:

[0160] Receive the given power sent by the monitoring system;

[0161] Determine whether the absolute value of the difference between the given power and the given feedback value of the speed regulator power corresponding to the large-scale bulb cross-flow type unit is less than or equal to a preset first power threshold; if so, determine that the given power issued by the monitoring system is correct; if correct, determine the second reference value of the guide vane opening of each large-scale bulb cross-flow type unit corresponding to the secondary frequency modulation according to the total given power and the total actual power; otherwise, determine that the given power issued by the monitoring system is wrong.

[0162] Furthermore, the second frequency modulation module 300 is also used for:

[0163] respectively determining the absolute value of the difference between the given power and the actual power generated by the large bulb tubular unit;

[0164] When the absolute value of the difference is greater than or equal to a preset first power threshold, a second reference value of the guide vane opening is calculated using a fast adjustment module;

[0165] When the absolute value of the difference is less than a preset first power threshold, a power regulation PID module is used to calculate a second reference value of the guide vane opening.

[0166] In the embodiment of the present disclosure, the third frequency modulation module 400 is further used for:

[0167] Step E1: Determine whether the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant is greater than a preset frequency dead zone threshold, if so, proceed to step E2, otherwise do not execute;

[0168] Step E2: determining whether the load change value is caused by the change in water head, if so, starting a frequency modulation, otherwise starting a small load distribution for each large bulb tubular unit in the hydropower plant;

[0169] Step F3: obtaining the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant after starting the first frequency modulation or starting the first small load distribution, and determining the range to which the difference belongs. When the difference belongs to the preset frequency dead zone, the secondary frequency modulation is not performed. When the difference is equal to the preset first power threshold, the load is manually distributed to each large bulb flow-through unit through the monitoring system. When the difference is greater than the preset second power threshold, the secondary frequency modulation is started to distribute the load equally to each large bulb flow-through unit.

[0170] The large power deviation marking strategy includes: step E1 and step E2.

[0171] Furthermore, the third frequency modulation module 400 is also used for:

[0172] When the action directions required by the secondary frequency modulation and the primary frequency modulation action instructions are the same, the two instructions are superimposed and processed to issue a comprehensive instruction to the large bulb tubular unit;

[0173] When the action directions required by the secondary frequency regulation and primary frequency regulation action instructions are different, if the power grid requires the plant to give priority to ensuring the unit output, then choose to lock the primary frequency regulation action instruction. If the power grid requires the plant to give priority to responding to the grid frequency regulation needs, then choose to lock the secondary frequency regulation action instruction.

[0174] In summary, the frequency regulation control system for a large bulb tubular unit proposed in this embodiment can effectively improve the unit's power generation output operating conditions and enhance the unit's frequency regulation performance.

[0175] Embodiment 3

[0176] In order to implement the above embodiments, the present disclosure further proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in Embodiment 1 is implemented.

[0177] Embodiment 4

[0178] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.

[0179] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0180] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0181] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A frequency modulation control strategy for a large bulb tubular unit, characterized in that: The control strategy includes: Obtain frequency deviation and load change values ​​of the power system; When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once; When the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, performing secondary frequency modulation on each large bulb tubular unit in the hydropower plant; When the frequency deviation of the power system is greater than the preset frequency dead zone and the load change value is greater than or equal to the preset first load change threshold, primary and secondary frequency regulation is performed on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy.

2. The control strategy according to claim 1, characterized in that: When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is less than a preset first load change threshold, each large bulb tubular unit in the hydropower plant is frequency-regulated once, including: Obtain the sampling frequency of each large bulb tubular unit in the hydropower plant and the set frequency issued by the corresponding turbine speed control system; Determine a first reference value of the guide vane opening of the large bulb tubular unit according to the sampling frequency and the set frequency; The large bulb tubular flow unit is adjusted based on the first reference value of the guide vane opening to achieve primary frequency regulation of each large bulb tubular flow unit in the hydropower plant.

3. The control strategy according to claim 2, characterized in that: The calculation formula for the first reference value of the guide vane opening of the nth large bulb tubular unit is as follows: Y pid,n =C n ×(K p,n +K i,n +K d,n ) Where Y pid,n is the first reference value of the guide vane opening of the nth large bulb tubular unit, C n is the frequency difference of the nth large bulb tubular unit, K p,n is the proportional gain of the nth large bulb tubular unit, K i,n is the integral gain of the nth large bulb flow unit, K d,n is the differential gain of the nth large bulb tubular unit; in, In the formula, f c,n is the set frequency of the nth large bulb tubular unit, f g,n is the sampling frequency of the nth large bulb tubular unit, r is the preset frequency dead zone threshold.

4. The control strategy according to claim 3, characterized in that: When the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, before performing secondary frequency modulation on each large bulb tubular unit in the hydropower plant, the method further includes: Receive the given power sent by the monitoring system; Determine whether the absolute value of the difference between the given power and the given feedback value of the speed regulator power corresponding to the large-scale bulb cross-flow type unit is less than or equal to a preset first power threshold; if so, determine that the given power issued by the monitoring system is correct; if correct, determine the second reference value of the guide vane opening of each large-scale bulb cross-flow type unit corresponding to the secondary frequency modulation according to the total given power and the total actual power; otherwise, determine that the given power issued by the monitoring system is wrong.

5. The control strategy according to claim 4, characterized in that: When the frequency deviation of the power system is less than or equal to the preset frequency dead zone, and the load change value is greater than the preset first load change threshold, the large bulb tubular units in the hydropower plant are subjected to secondary frequency modulation, including: respectively determining the absolute value of the difference between the given power and the actual power generated by the large bulb tubular unit; When the absolute value of the difference is greater than or equal to a preset first power threshold, a second reference value of the guide vane opening is calculated using a fast adjustment module; When the absolute value of the difference is less than a preset first power threshold, a power regulation PID module is used to calculate a second reference value of the guide vane opening.

6. The control strategy according to claim 4, characterized in that: When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, primary and secondary frequency regulation is performed on each large bulb tubular unit in the hydropower plant based on a large power deviation marking strategy, including: Step F1: Determine whether the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant is greater than a preset frequency dead zone threshold, if so, proceed to step F2, otherwise do not execute; Step F2: determine whether the load change value is caused by the change in water head, if so, start frequency modulation, otherwise start small load distribution for each large bulb tubular unit in the hydropower plant; Step F3: obtaining the difference between the total given power of the hydropower plant and the total actual power of the hydropower plant after starting the first frequency modulation or starting the first small load distribution, and determining the range to which the difference belongs. When the difference belongs to the preset frequency dead zone, the secondary frequency modulation is not performed. When the difference is equal to the preset first power threshold, the load is manually distributed to each large bulb flow-through unit through the monitoring system. When the difference is greater than the preset second power threshold, the secondary frequency modulation is started to distribute the load equally to each large bulb flow-through unit. The large power deviation marking strategy includes: step F1 and step F2.

7. The control strategy according to claim 6, characterized in that: When the frequency deviation of the power system is greater than a preset frequency dead zone, and the load change value is greater than or equal to a preset first load change threshold, performing primary and secondary frequency regulation on each large bulb tubular unit in the hydropower plant based on a large power deviation marking strategy also includes: When the action directions required by the secondary frequency modulation and the primary frequency modulation action instructions are the same, the two instructions are superimposed and processed to issue a comprehensive instruction to the large bulb tubular unit; When the action directions required by the secondary frequency regulation and primary frequency regulation action instructions are different, if the power grid requires the plant to give priority to ensuring the unit output, then choose to lock the primary frequency regulation action instruction. If the power grid requires the plant to give priority to responding to the grid frequency regulation needs, then choose to lock the secondary frequency regulation action instruction.

8. A frequency modulation control system for a large bulb tubular unit, characterized in that: The control system comprises: An acquisition module, used for acquiring frequency deviation and load change values ​​of the power system; A first frequency modulation module, configured to perform a frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is less than a preset first load change threshold; A second frequency modulation module is used to perform secondary frequency modulation on each large bulb tubular unit in the hydropower plant when the frequency deviation of the power system is less than or equal to a preset frequency dead zone and the load change value is greater than a preset first load change threshold; The third frequency regulation module is used to perform primary and secondary frequency regulation on each large bulb flow-through unit in the hydropower plant based on the large power deviation marking strategy when the frequency deviation of the power system is greater than a preset frequency dead zone and the load change value is greater than or equal to a preset first load change threshold.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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