Method and system for adjusting frequency of speed regulator of hydroelectric generating set

Abstract

The invention discloses a hydroelectric generating set speed regulator frequency adjusting method and system, and the method comprises the steps: obtaining the initial state data of a set, and obtaining a set inertia time constant through a throwing test method; based on the unit inertia time constant and in combination with the unit operation parameters, constructing a rotation kinetic energy relation model to obtain power deviation; and according to different states of the speed regulator, performing corresponding frequency optimization regulation on the unit system through the power deviation. Notches or redundant energy corresponding to frequency changes is obtained based on the principle of energy conservation through the relation between the unit rotating speed (system frequency) and unit rotating kinetic energy, under different working conditions, frequency adjustment of a prime mover by a speed regulator is achieved quickly, accurately and stably, and the method is suitable for power frequency adjustment of a pure inertial system; meanwhile, the method is also suitable for a power grid with a large new energy occupation ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency regulation of hydroelectric generator set equipment, and in particular to a frequency regulation method and system for a hydroelectric generator set speed regulator. Background Art

[0002] There are many frequency control methods for hydropower plant turbine generator sets. The frequency control of the unit or the power grid is mainly completed by the power plant governor. The application scenarios of the governor controlling the unit frequency are mainly three cases: the first is under no-load conditions (the unit is disconnected from the power grid), the governor control model adopts the frequency mode, no frequency dead zone, no adjustment rate bp, and accurately completes the frequency regulation of the unit. The second is under power generation conditions, which is divided into two categories. One is the isolated grid (a single unit governor adjusts the unit output and can change the frequency of the power grid). The governor control model adopts the isolated grid frequency mode. Generally, the frequency dead zone is set, and the small adjustment rate bp is set to complete the unit frequency (also the isolated grid frequency) regulation. The third type is under power generation conditions. The other type is a large grid (a single unit speed governor adjusts the unit output, which is approximately equivalent to the frequency of the grid being unable to change). The speed governor control model adopts the large grid primary frequency mode. Generally, a frequency dead zone is set with a large adjustment rate bp to perform a primary frequency regulation emergency load adjustment of the grid frequency to complete a certain limit of frequency adjustment.

[0003] However, for the above three control modes, the speed regulator in the industry adopts the traditional PID structure and differential regulation with the permanent slip coefficient bp as negative feedback. If differential regulation is adopted, the speed regulator cannot complete the accurate and stable regulation of the grid frequency in the isolated grid and large grid modes under power generation conditions; the current speed regulator control structure cannot adapt to multiple conditions; at the same time, due to the differences in the water diversion systems of hydropower stations, the changes in the water head and load sections of the power stations, and the output response characteristics of the turbines are all different, and the PID parameters are difficult to adapt to the full range. Under large frequency difference fluctuations, the frequency is prone to multi-cycle oscillations and is difficult to converge quickly. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a frequency regulation method and system for a hydropower unit speed regulator to solve the problems that the current speed regulator control structure cannot adapt to multiple working conditions; the differential regulation cannot achieve accurate and stable regulation of the grid frequency; the output response characteristics of the turbines are all different, and under large frequency difference fluctuations, the frequency is prone to multi-cycle oscillation and is difficult to converge quickly.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a method for adjusting the frequency of a speed governor of a hydropower unit, comprising:

[0008] Obtain the initial state data of the unit and obtain the unit inertia time constant through the throw test method;

[0009] Based on the unit inertia time constant and combined with the unit operating parameters, a rotational kinetic energy relationship model is constructed to obtain the power deviation;

[0010] According to different states of the speed governor, the frequency of the unit system is optimized and adjusted accordingly through the power deviation.

[0011] As a preferred solution of the frequency regulation method of the speed governor of a hydropower unit described in the present invention, the inertia time constant of the unit is obtained by a swing test method, including:

[0012] When the main switch of the unit trips and before the guide vanes start to move, the mechanical power of the unit is completely converted into kinetic energy and stored in the shaft system of the rotating equipment of the unit;

[0013] The angular acceleration of the rotor is obtained by fitting the frequency recording data, and the inertia time constant of the unit is calculated by combining the per-unit value of the mechanical torque.

[0014] As a preferred solution of the frequency adjustment method of the speed governor of a hydropower unit described in the present invention, a rotational kinetic energy relationship model is constructed based on the inertia time constant of the unit and combined with the unit operating parameters, including:

[0015] Construct the relationship between the angular velocity, unit speed and frequency of the hydro-generator;

[0016] The frequencies are retained for classification, and the rotational kinetic energy relationship model is calculated based on the principle model of rotational kinetic energy.

[0017] As a preferred solution of the frequency adjustment method of the speed regulator of a hydropower unit described in the present invention, obtaining the power deviation includes:

[0018] After the rotation speed changes, the energy change value is obtained based on the difference of the rotational kinetic energy relationship model before and after the change;

[0019] The power deviation is obtained by the ratio of the energy change value to the frequency adjustment time.

[0020] As a preferred solution of the frequency adjustment method of the hydropower unit speed governor of the present invention, it further comprises: judging whether it is necessary to calculate the power deviation based on whether the current unit frequency exceeds the dead zone;

[0021] If the current unit frequency does not exceed the frequency dead zone, no calculation will be performed;

[0022] If the current unit frequency exceeds the frequency dead zone, it is compared with the rated frequency and the power deviation is calculated through the rotational kinetic energy relationship model.

[0023] As a preferred solution of the frequency adjustment method of the speed governor of the hydropower unit described in the present invention, wherein: according to different states of the speed governor, the frequency of the unit system is optimized and adjusted accordingly through the power deviation, including: if the speed governor is in the large grid power generation opening mode, a frequency adjustment is performed;

[0024] Or, the power grid is in an isolated condition and the speed regulator is in frequency regulation mode;

[0025] The calculated power deviation is input into the second PID for power regulation;

[0026] The first PID participates in the calculation, controls the output, and acts on the unit power.

[0027] As a preferred solution of the frequency adjustment method of the speed governor of the hydropower unit described in the present invention, wherein: according to different states of the speed governor, the frequency of the unit system is optimized and adjusted accordingly through the power deviation, including:

[0028] If a frequency regulation is performed in the large-grid power generation mode, the calculated power deviation and the current power setting are superimposed to obtain the first power data;

[0029] The first power data is then subtracted from the power feedback to obtain the second power data;

[0030] The second power data is back-calculated into a frequency difference through a modulation rate link, and input into a third PID for power regulation;

[0031] The frequency difference input of the original frequency regulation is still involved in the calculation when it is input to the third PID, and the control output is performed to act on the unit power.

[0032] In a second aspect, the present invention provides a frequency regulation system for a speed governor of a hydropower unit, comprising: an experimental calculation module for obtaining initial state data of the unit and obtaining an inertia time constant of the unit through a throw test method;

[0033] A model building module is used to build a rotational kinetic energy relationship model based on the unit inertia time constant and combined with the unit operating parameters to obtain power deviation;

[0034] The regulating module is used to perform corresponding frequency optimization regulation on the unit system according to different states of the speed regulator through the power deviation.

[0035] In a third aspect, the present invention provides an electronic device, comprising:

[0036] Memory and processor;

[0037] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the method for frequency regulation of the speed regulator of the hydropower unit are implemented.

[0038] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for frequency regulation of a speed regulator of a hydropower unit.

[0039] Compared with the prior art, the present invention has the following beneficial effects: the present invention measures the relationship between the unit speed (system frequency) and the unit rotational kinetic energy, obtains the gap or excess energy corresponding to the frequency change based on the principle of energy conservation, and realizes the energy regulation of the prime mover by the speed regulator under different working conditions, realizes frequency regulation quickly, accurately and stably, and is suitable for the power frequency regulation of pure inertial systems; at the same time, the conventional PID regulation of the differential adjustment method is retained in the speed regulator optimization control strategy, so as to be suitable for power grids with a relatively large proportion of new energy, such as power injection of power electronics such as photovoltaics. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0041] Figure 1 It is a schematic diagram of the overall flow of a method for adjusting the frequency of a speed regulator of a hydropower unit according to an embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of the control structure of a conventional speed regulator for primary frequency regulation of a large grid or frequency regulation under isolated grid conditions in a medium-opening closed loop of a speed regulator frequency regulation method for a hydropower unit according to an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the control structure of a conventional speed regulator for the next frequency regulation of a power closed-loop large grid in a method for regulating the speed regulator frequency of a hydropower unit according to an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the acceleration process curve of the unit when 100% load is shed in the frequency adjustment method of the speed regulator of the hydropower unit according to one embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of a program execution flow of frequency difference-free regulation of a speed regulator in various modes in a method for regulating the speed regulator frequency of a hydropower unit according to an embodiment of the present invention;

[0046] Figure 6 A schematic diagram of a frequency regulation control optimization strategy under a closed-loop speed governor opening in a method for regulating the frequency of a speed governor of a hydropower unit according to an embodiment of the present invention;

[0047] Figure 7 A schematic diagram of a frequency regulation control optimization strategy under a closed-loop power condition of a speed regulator in a frequency regulation method for a hydropower generator set according to an embodiment of the present invention;

[0048] Figure 8 It is a schematic diagram of the recording of a 635MW load test in a frequency adjustment method for a hydropower generator set speed governor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0050] Example 1

[0051] Reference Figure 1-Figure 3 , as an embodiment of the present invention, provides a method for adjusting the frequency of a speed governor of a hydropower unit, comprising:

[0052] S100: Acquire the initial state data of the unit, and obtain the inertia time constant of the unit through a throw test method;

[0053] S200: Based on the unit inertia time constant and combined with the unit operating parameters, a rotational kinetic energy relationship model is constructed to obtain power deviation;

[0054] S300: According to the different states of the speed governor, the frequency of the unit system is optimized and adjusted accordingly through power deviation.

[0055] It should be noted that the current application scenarios of speed governors controlling unit frequency are mainly three situations:

[0056] (1) Under no-load conditions, the speed governor control model adopts the frequency mode, with no frequency dead zone and no adjustment rate bp, and accurately completes the frequency regulation of the unit.

[0057] (2) Under power generation conditions, in an isolated grid, the governor control model adopts the isolated grid frequency mode. Generally, the frequency dead zone is set, and the small adjustment rate bp is used to complete the unit frequency regulation.

[0058] (3) Under power generation conditions, the governor control model adopts the large grid primary frequency mode. Generally, the frequency dead zone is set, the large adjustment rate bp is set, and the primary frequency regulation emergency load adjustment of the grid frequency is carried out to complete the frequency adjustment within a certain limit.

[0059] Specifically, the three situations can be summarized and compared using Table 1.

[0060] Table 1 Three control modes and parameter configurations used by the speed regulator for frequency regulation

[0061]

[0062] According to the three control modes in Table 1, the speed regulator in the industry adopts the traditional PID structure and differential regulation with the permanent slip coefficient bp as negative feedback.

[0063] If differential regulation is used, the speed regulator will not be able to achieve accurate and stable regulation of the grid frequency in the isolated grid and large grid modes under power generation conditions.

[0064] Therefore, based on the principle study of the control object, the inertia time constant T of the unit is calculated and obtained. a , which is defined as the time required for the unit to accelerate from 0 speed to rated speed under the action of rated torque. It is a measure of the inertia of the unit during rotation, and numerically it is the ratio of the unit's momentum moment at rated speed to the rated torque. This establishes a data relationship and further improves the existing control method.

[0065] The establishment of data relationships is a rotational kinetic energy relationship model constructed from the perspective of energy conservation. Specifically, the prime mover is the turbine Pt, which is the source of all energy. According to the law of energy conservation, it is converted into two parts, one part is the active power (electric energy) generated by the generator and sent to the power grid, and the other part is converted into the rotational kinetic energy of the unit. The rated frequency in China is 50Hz (this is an example for description purposes and is not limited to this value. For example, the rated frequency in other countries is 40Hz), which corresponds to the rated speed of each unit.

[0066] For traditional power grids, the relationship between the three is:

[0067] P t =P e +E 50

[0068] The essence of the stable operation of the power grid system, from the perspective of energy balance, is to maintain the above formula. However, the difficulty and key point is that Pe changes in real time, to varying degrees, and unpredictably. At this time, Pt should theoretically change at any time to maintain E 50In fact, it is also moving in this direction. The power grid dispatcher is very likely to adjust P according to various models, big data and methods. t , try to ensure that this formula holds.

[0069] But in fact P t It is impossible to follow the adjustment perfectly. t If the speed is insufficient and is not adjusted in the direction of increase, the unit speed will automatically slow down according to the self-stability of the system. 50 will become smaller; that is, the external manifestation is that the frequency decreases. On the contrary, if P t If the speed is too large and is not adjusted in the direction of reduction, the unit speed will automatically increase according to the self-stability of the system. 50 It will become larger; that is, the external manifestation is an increase in frequency.

[0070] The conventional practice is that the speed regulator detects the frequency deviation, sends it to the PID module for calculation, and then adjusts the opening or power. The size of the action is only related to bp and the frequency difference Δx, and is not responsible for adjusting the frequency difference to 0. It is just an automatic response to the correctness of the direction.

[0071] In response to the fluctuation of grid frequency, the commonly used strategies are as follows: Figure 2 As shown, it is a block diagram of the closed-loop primary frequency regulation of the speed regulator opening in a large power generation grid, or the frequency regulation of the speed regulator under isolated grid conditions.

[0072] According to the PID transfer function, the relationship between input and output in steady state is:

[0073]

[0074] From Δy, it can be seen that the output guide vane opening Δy and frequency difference Δx are just a simple adjustment relationship, which is essentially a proportional relationship. The calculation result is not responsible for eliminating the input deviation.

[0075] The control structures of primary frequency modulation and isolated grid mode are basically the same at this time, and the main differences lie in the dead zone E, bp and PID parameters.

[0076] Another strategy is Figure 3 As shown, it is the regulation block diagram of the closed-loop primary frequency regulation of the speed regulator in the power generation grid.

[0077] According to the PID transfer function, the relationship between input and output in steady state is:

[0078]

[0079] From Δp, we can know that the output active power change Δp and frequency difference Δx are just a simple adjustment relationship, which is essentially a proportional relationship. The calculation result is not responsible for eliminating the input deviation. At the same time, in the isolated network mode, according to the transfer function, the control structure of the speed regulator power mode cannot be used.

[0080] According to the above specific problems, the present invention, through the above steps S100-S300, as a whole, follows the principle of electromechanics, that is: the frequency of the power grid is determined by the rotational speed of all units, and its size reflects the level of rotational energy of the units connected in parallel in the system; especially in a pure inertial power grid system (the units belonging to the power grid are composed of traditional rotating prime movers and generators, such as hydropower, thermal power, nuclear power, wind power and other units), if the relationship between the rotational speed and energy of the unit is known, under the premise of this data, the speed regulator can quickly complete the precise adjustment of the frequency, which greatly relieves the calculation amount of PID.

[0081] Example 2

[0082] Reference Figure 1 and Figure 4-Figure 7 , which is an embodiment of the present invention, provides a frequency adjustment method for a speed regulator of a hydropower unit based on the above embodiment.

[0083] In the implementation manner of the present application, the initial state data of the unit is obtained in step S100, including obtaining the load shedding conditions of the unit, for example: the unit sheds at least 50% of the rated load; as well as the unit frequency, guide vane opening, and active power.

[0084] In an optional implementation, the initial state data of the unit is obtained in step S100, which may include reactive power, generator terminal voltage, rotation speed, etc. in addition to the above data.

[0085] In another optional implementation, the initial state data of the unit is obtained in step S100, which may include turbine temperature and pressure, etc. in addition to the above data.

[0086] In the embodiment of the present application, in step S100, the inertia time constant T of the unit is obtained by the swing test method. a ,include:

[0087] When the main switch of the unit trips and before the guide vanes start to move, the mechanical power of the unit is completely converted into kinetic energy and stored in the shaft system of the rotating equipment of the unit;

[0088] The angular acceleration of the rotor is obtained by fitting the frequency recording data, and the unit inertia time constant T is calculated by combining the mechanical torque standard value. a .

[0089] Specifically, the above process can be expressed by the formula:

[0090]

[0091] Among them, T a is the unit inertia time constant, α * is the rotor acceleration per unit value, ΔT M * It is the per unit value of mechanical torque, which is 1 in this state.

[0092] It should be noted that the unit inertia time constant T a , which is defined as the rated torque M r Under the action of r The time required. It is a measure of the inertia of the unit during rotation, and numerically it is the ratio of the unit's angular momentum to the rated torque at rated speed.

[0093] Therefore, theoretically, the unit inertia time constant T a It can also be expressed by the following formula:

[0094]

[0095] According to the laws of physics, we know that:

[0096]

[0097] According to the above three formulas, we can get:

[0098]

[0099] In the formula, Jω r is the kinetic moment of the unit at rated speed, kg·m 2 / s;M r is the rated torque of the unit, N·m 2 ;GD 2 is the unit flywheel torque, kN·m 2 ;n r is the rated speed of the unit, r / min; P r is the rated power of the unit, kW.

[0100] Specifically, when GD 2 , P r and n r Use t·m 2 , kW and r / min as units:

[0101]

[0102] It should also be noted that formula (3) is only a theoretical formula, the calculation is not operational, and it is difficult to accurately calculate the flywheel torque GD of the rotating part of the unit.2 . Because it consists of three parts. a It includes not only the mechanical inertia of the rotating part of the generator, but also the mechanical inertia of the rotating part of the turbine (including the main shaft) and the mechanical inertia of the water body in the turbine runner area. That is:

[0103]

[0104] in, It is the mechanical inertia of the rotating part of the generator; is the mechanical inertia of the rotating part of the turbine; is the mechanical inertia of the water in the turbine runner area;

[0105] Calculated value GD 2 Due to the uneven distribution of mass and density, the local irregular size is difficult to measure, which makes it difficult to calculate accurately. If you want to accurately calculate an actual GD 2 , we can start from formula (3) and first calculate T a , we can inversely calculate GD 2 .

[0106] Back to T again a The original definition and basic meaning of T a It represents the degree of influence of energy release on the speed change rate of the unit under rated power. Under rated load, through load rejection test, energy is instantly released to the unit, and then the speed change is measured by technical means (speed measurement, wave recording) to calculate the unit's T a .

[0107] That is: through the on-site test: load shedding test, the T a .

[0108] The details are as follows: The unit is under full load, and the load shedding test data is obtained, such as Figure 4 As shown in the load shedding waveform, the slope d (Δn / n r ) / dt;

[0109] It can be expressed as the following formula (5):

[0110]

[0111] Among them, p 0 is the unit load rejection amplitude, kW; Δn is the unit speed change, r / min.

[0112] At the moment of load shedding, the unit's active power and mechanical torque are the same, that is, when the load is 100%, the unit value = 100%, that is, 1;

[0113] The error is small when the unit is fully loaded, that is, p 0 =p r , substituting into formula (5) we can get:

[0114]

[0115] or

[0116]

[0117] That is, formula (5) and formula (1) have the same meaning, and we can get:

[0118] In an optional embodiment, the unit inertia time constant T is obtained in step S100. a Can also correspond Figure 4 , the vertical and horizontal coordinates show that the reciprocal is the tangent slope; combined with formula (6), the tangent slope with the maximum initial frequency is obtained from the curve, and then extended, when Δn / n r =1, that is, when the unit reaches the rated speed, the corresponding horizontal axis is T a .

[0119] In another optional embodiment, the unit inertia time constant T a The calculation of T can also be realized online. The speed governor automatically calculates T by collecting data, analyzing and calculating, and taking advantage of the load shedding opportunity of the unit. a .

[0120] It should also be noted that, according to the above description, T a has become a known number. Therefore, according to formula (5), we can find:

[0121]

[0122] In formula (7), P r and n r The units are kW and r / min respectively; and for a hydropower unit operating on site, these two quantities are clear.

[0123] In the implementation manner of the present application, before step S200, as Figure 5 As shown, it may also include determining whether it is necessary to calculate the power deviation based on whether the current unit frequency exceeds the dead zone;

[0124] If the current unit frequency does not exceed the frequency dead zone, no calculation will be performed;

[0125] If the current unit frequency exceeds the frequency dead zone, it is compared with the rated frequency and the power deviation is calculated through the rotational kinetic energy relationship model.

[0126] In the implementation manner of the present application, in step S200, based on the inertia time constant of the unit and in combination with the unit operation parameters, a rotational kinetic energy relationship model is constructed, including:

[0127] Construct the relationship between the angular velocity, unit speed and frequency of the hydro-generator;

[0128] The frequencies are retained for classification, and the rotational kinetic energy relationship model is calculated based on the principle model of rotational kinetic energy.

[0129] Specifically, the basic formula of the principle model of rotational kinetic energy is:

[0130]

[0131] The relationship among the angular velocity ω, unit speed n, and frequency f of the hydro-generator is established as follows:

[0132]

[0133] n=60f / P (unit: r / min)

[0134] Where P is the number of pole pairs of the generator set, which is a constant;

[0135] Keep the frequency f for classification and substitute it into formula (8) to get:

[0136]

[0137] Substituting formula (7) into the above formula, we get:

[0138]

[0139] In the implementation manner of the present application, obtaining the power deviation in step S200 includes:

[0140] After the rotation speed changes, the energy change value is obtained based on the difference of the rotational kinetic energy relationship model before and after the change;

[0141] The power deviation is obtained by the ratio of the energy change value to the frequency adjustment time.

[0142] Specifically, after the rotation speed changes, the energy change value is expressed as:

[0143]

[0144] Among them, W 1 is the power after the change, W 0 is the power before the change;

[0145] The power deviation is obtained by the ratio of the energy change value to the frequency adjustment time.

[0146] For example, according to the industry standard, the frequency adjustment time is not more than 12s, and T=12s can be taken here, then the power deviation is expressed as:

[0147]

[0148] In the implementation manner of the present application, in step S300, if Figure 5 and Figure 6 As shown, according to the different states of the speed governor, the unit system is adjusted to optimize the frequency accordingly through the power deviation, including:

[0149] If the speed regulator is in the large grid power generation opening mode, a frequency regulation is performed;

[0150] Or, the power grid is in an isolated condition and the speed regulator is in frequency regulation mode;

[0151] The calculated power deviation is input into the second PID for power regulation;

[0152] The first PID still participates in the calculation, controls the output, and acts on the unit power.

[0153] It should be noted that the parameters of the two groups of PID modules are different, and the parameters are finally determined on site through input steps.

[0154] In the implementation manner of the present application, in step S300, if Figure 5 and Figure 7 As shown, according to the different states of the speed governor, the unit system is adjusted to optimize the frequency accordingly through the power deviation, including:

[0155] If a frequency regulation is performed in the large-grid power generation mode, the calculated power deviation and the current power setting are superimposed to obtain the first power data;

[0156] The first power data is then subtracted from the power feedback to obtain the second power data;

[0157] The second power data is back-calculated into a frequency difference through a modulation rate link, and input into a third PID for power regulation;

[0158] The frequency difference input of the original frequency regulation is still involved in the calculation when it is input to the third PID, and the control output is performed to act on the unit power.

[0159] It should be noted that in this step, in the two control loops, since the objects input to the PID are both frequency differences, the parameters are the same set of parameters.

[0160] It should also be noted that in step S300, since the relationship between frequency and power has been established in the previous steps, a power regulation module or function can be superimposed on the frequency control strategy of the speed regulator on the basis of the classic PID, thereby getting rid of the calculation dependence on bp (ep) and enabling the speed regulator to complete the increase or decrease of active load at the unit end.

[0161] Figure 6 and Figure 7 The calculated value of medium power ΔP is expressed as an absolute value for the convenience of expression.

[0162] In an optional implementation manner, in fact, when the frequency is high (exceeding the frequency dead zone E), negative power should be calculated; when the frequency is low (less than the frequency dead zone - E), positive power should be calculated.

[0163] In summary, the present invention uses the unit time constant obtained by load shedding to reversely calculate the actual rotational inertia of the unit; uses the rotational inertia and the known parameters of the unit itself to establish the relationship equation between the unit frequency and rotational kinetic energy (power); combines the known equations to optimize the frequency adjustment method of the speed regulator under different working conditions and different modes, and provides a specific control strategy. According to the ideas and principles of this invention, from the perspective of the power grid and from the perspective of secondary frequency regulation, the "total load adjustment method" of the unit can be adopted. That is, according to the above method, the power that needs to be adjusted for each unit is obtained, that is: Then the total load adjustment is centralized and sent to a frequency regulation power plant or unit to be completed individually. This method is particularly effective for power grids composed of pure inertial units.

[0164] Example 3

[0165] Refer to Table 2 and Figure 8 Based on the previous embodiment, this embodiment provides an application case of a frequency adjustment method for a hydropower unit speed regulator to illustrate the feasibility and beneficial effects of our solution.

[0166] Take the 18# unit of Xiluodu Power Plant as an example:

[0167] (1) Load rejection test

[0168] Test conditions and requirements: The unit operates normally, the regulation and control system is stable, other dynamic tests have been completed, the unit has load shedding conditions (the unit sheds at least 50% of the rated load), and the test records at least record the unit frequency, guide vane opening, and active power.

[0169] Test purpose: To test the moment of inertia of the hydro-turbine generator set.

[0170] The load rejection curve of Xiluodu #18 unit 635MW is as follows Figure 8 As shown, the rotor time constant of the unit can be calculated based on the frequency in this figure.

[0171] After the unit main switch trips and before the guide vanes start to move, the unit's mechanical power is completely converted into kinetic energy and stored in the unit's rotating equipment shaft system. At this time, the turbine torque can be considered constant. The frequency recording data is used to fit the rotor's angular acceleration, and the rotor inertia time constant is calculated using the following formula. Among them, Ta is the unit inertia time constant (s), α* is the rotor acceleration per unit value, and TM* is the mechanical torque per unit value.

[0172] ΔT M * =T a ×α *

[0173] This test is a 635MW load shedding test. Figure 7 α is obtained by fitting the data 1s after the medium load rejection. * is 0.081, then

[0174] (2) List the known quantity data table

[0175] Create a known quantity data table 2 as follows:

[0176] Table 2 Parameters of prime mover of unit #18 of Xiluodu Hydropower Station

[0177] Serial number name Design value 1 Factory Station Name Xiluodu Hydropower Plant 2 Unit No. #18 3 Rated power Pr 770*103kW 4 Pole pair number P 24 5 Rated speed nr 125r / min 6 The actual measured unit inertia time constant Ta 12.34s 7 Turbine Type Vertical shaft mixed flow

[0178] (3) Solution for unit rotational kinetic energy / power

[0179] According to the known data in Table 2, assuming that the frequency changes to f1 is 50.1 Hz and the initial frequency f0 is 50 Hz, substituting into formula (9), the power change can be calculated.

[0180]

[0181] ΔP=1.58×10 3 kW=1.58MW

[0182] The frequency is 50.1Hz, the unit should reduce output, and the load size is 1.58MW. In the system, the speed governor of each machine is calculated and adjusted as above, which can accurately balance the gap between power generation and power load, make up for the excess or insufficient mechanical power in a targeted manner, and finally achieve accurate frequency regulation without difference.

[0183] Example 4

[0184] The above is a schematic scheme of a method for adjusting the frequency of a hydropower unit speed regulator in this embodiment. It should be noted that the technical scheme of the system for adjusting the frequency of the hydropower unit speed regulator and the technical scheme of the method for adjusting the frequency of the hydropower unit speed regulator described above belong to the same concept, and the details of the technical scheme of the system for adjusting the frequency of the hydropower unit speed regulator in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the method for adjusting the frequency of the hydropower unit speed regulator described above.

[0185] This embodiment also provides a system for a method for adjusting the frequency of a speed regulator of a hydropower unit, comprising:

[0186] An acquisition module, used for acquiring partial discharge pulse signals through dual sensors;

[0187] An acquisition module, used for respectively calculating the characteristics of partial discharge pulse signals;

[0188] A feature map construction module, used to construct a feature map based on the calculated partial discharge pulse signal features;

[0189] The separation and judgment module is used to judge the signal-to-noise ratio information in the characteristic spectrum, separate the noise signal and the effective partial discharge signal, so as to determine the discharge type.

[0190] This embodiment also provides an electronic device suitable for frequency regulation of a hydropower unit speed regulator, comprising: a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the method for frequency regulation of a hydropower unit speed regulator as proposed in the above embodiment.

[0191] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for adjusting the frequency of a speed regulator of a hydropower unit as proposed in the above embodiment is implemented.

[0192] The storage medium proposed in this embodiment and the method for implementing the frequency adjustment of the hydropower unit speed regulator proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0193] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (Random Access Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0194] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for adjusting the frequency of a speed governor of a hydropower unit, characterized in that: include: Obtain the initial state data of the unit and obtain the unit inertia time constant through the throw test method; Based on the unit inertia time constant and combined with the unit operating parameters, a rotational kinetic energy relationship model is constructed to obtain the power deviation; According to different states of the speed governor, the frequency of the unit system is optimized and adjusted accordingly through the power deviation.

2. The method for adjusting the frequency of the speed governor of a hydropower unit according to claim 1, characterized in that: Through the test method, the inertia time constant of the unit is obtained, including: When the main switch of the unit trips and before the guide vanes start to move, the mechanical power of the unit is completely converted into kinetic energy and stored in the shaft system of the rotating equipment of the unit; The angular acceleration of the rotor is obtained by fitting the frequency recording data, and the inertia time constant of the unit is calculated by combining the per-unit value of the mechanical torque.

3. The method for adjusting the frequency of the speed governor of a hydroelectric generator set according to claim 2, characterized in that: Based on the unit inertia time constant and combined with the unit operating parameters, a rotational kinetic energy relationship model is constructed, including: Construct the relationship between the angular velocity, unit speed and frequency of the hydro-generator; The frequencies are retained for classification, and the rotational kinetic energy relationship model is calculated based on the principle model of rotational kinetic energy.

4. The method for adjusting the frequency of the speed governor of a hydroelectric generator set according to claim 3, characterized in that: Obtaining power deviation includes: After the rotation speed changes, the energy change value is obtained based on the difference of the rotational kinetic energy relationship model before and after the change; The power deviation is obtained by the ratio of the energy change value to the frequency adjustment time.

5. The method for adjusting the frequency of the speed governor of a hydroelectric generator set according to claim 4, characterized in that: It also includes determining whether it is necessary to calculate the power deviation based on whether the current unit frequency exceeds the dead zone; If the current unit frequency does not exceed the frequency dead zone, no calculation will be performed; If the current unit frequency exceeds the frequency dead zone, it is compared with the rated frequency and the power deviation is calculated through the rotational kinetic energy relationship model.

6. The method for adjusting the frequency of the speed governor of a hydroelectric generator set according to claim 5, characterized in that: According to different states of the speed governor, the unit system is adjusted to optimize the frequency accordingly through the power deviation, including: if the speed governor is in the large grid power generation opening mode, a frequency adjustment is performed; Or, the power grid is in an isolated condition and the speed regulator is in frequency regulation mode; The calculated power deviation is input into the second PID for power regulation; The first PID participates in the calculation, controls the output, and acts on the unit power.

7. The method for adjusting the frequency of the speed governor of a hydroelectric generator set according to claim 6, characterized in that: According to different states of the speed governor, the unit system is adjusted to optimize the frequency accordingly through the power deviation, including: If a frequency regulation is performed in the large-grid power generation mode, the calculated power deviation and the current power setting are superimposed to obtain the first power data; The first power data is then subtracted from the power feedback to obtain the second power data; The second power data is back-calculated into a frequency difference through a modulation rate link, and input into a third PID for power regulation; The frequency difference input of the original frequency regulation is still involved in the calculation when it is input to the third PID, and the control output is performed to act on the unit power.

8. A system applied to the frequency adjustment method of a hydropower unit speed governor according to any one of claims 1 to 7, characterized in that: include: The experimental calculation module is used to obtain the initial state data of the unit and obtain the inertia time constant of the unit through the throwing test method; A model building module is used to build a rotational kinetic energy relationship model based on the unit inertia time constant and combined with the unit operating parameters to obtain power deviation; The regulating module is used to perform corresponding frequency optimization regulation on the unit system according to different states of the speed regulator through the power deviation.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the frequency adjustment method of the hydropower unit speed regulator described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for frequency regulation of a speed regulator of a hydropower unit as claimed in any one of claims 1 to 7.

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