Unit power control method and system based on synchronous-machine-free power supply system

Abstract

The invention discloses a unit power control method and system based on a synchronous-machine-free power supply system, and relates to the technical field of water turbine control, and the method comprises the steps: building a water turbine power control system, and collecting system operation parameters in real time through an online testing device; dividing a dynamic operation area of the water turbine according to the collected real-time operation parameters, and judging the operation area of the unit by combining the current water head and the real-time operation state of the unit; and selecting and executing a corresponding control strategy according to the determined unit operation area, performing decoupling control on the converter, and performing water turbine power control to optimize the system operation state. The method can better adapt to environmental water heads, always operates at the optimal rotating speed under different water heads, improves the operation efficiency and the adaptability of a unit, can realize decoupling control of active power and reactive power of the generator, and independently controls the active power and the reactive power of the generator.

Description

Technical Field

[0001] The invention relates to the technical field of water turbine control, in particular to a method and system for controlling unit power based on a non-synchronous machine power supply system. Background Art

[0002] As an important part of renewable energy, hydropower units have been widely used and developed around the world. Traditional hydropower units mainly use synchronous generators, which convert the energy of water flow into mechanical energy through turbines, and then drive the generator to generate electricity. However, with the increasing complexity of the operating environment of hydropower stations, especially in the face of large changes in water head, the traditional constant speed operation mode has gradually revealed its limitations. In order to solve these problems, researchers have proposed a variety of technical solutions in recent years, such as variable speed operation technology, intelligent control technology and decoupling control technology, to improve the adaptability and efficiency of hydropower units.

[0003] Although variable speed operation technology can improve the performance of hydro-turbine generator sets to a certain extent, there are still some shortcomings in practical applications. First, traditional variable speed operation technology often relies on fixed control strategies and is difficult to adapt to large changes in water head. Secondly, due to the complex dynamic characteristics of hydro-turbine units, traditional control methods face challenges in achieving efficient and stable operation, especially in terms of power output stability, efficiency and response time under different operating conditions. In addition, existing control strategies often ignore the mutual influence between different control loops when dealing with multivariable control problems, resulting in limited system performance. Therefore, a new unit power control method based on a non-synchronous machine power supply system is needed to improve the overall performance of hydro-turbine generator sets. Summary of the invention

[0004] In view of the problems existing in the existing power control method of the unit based on the non-synchronous machine power supply system, the present invention is proposed. Therefore, the problem to be solved by the present invention is how to provide a power control method and system of the unit based on the non-synchronous machine power supply system.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a unit power control method based on a non-synchronous machine power supply system, which includes constructing a turbine power control system, collecting system operating parameters in real time through an online testing device; dividing the dynamic operating area of ​​the turbine according to the collected real-time operating parameters, and judging the operating area of ​​the unit in combination with the current water head and the real-time operating status of the unit; selecting and executing a corresponding control strategy according to the determined unit operating area, decoupling the converter, and optimizing the operating status of the turbine power control system.

[0007] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, the turbine power control system includes a turbine guide vane control actuator, a turbine guide vane, a turbine rotor, a turbine generator stator and rotor, a transformer, a grid-side converter, a DC bus, a rotor-side converter and a controller.

[0008] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, wherein: the turbine includes a turbine rotor and a turbine guide vane, and the turbine rotor is connected to the turbine generator rotor; the rotor-side converter is connected to the turbine generator rotor through a three-phase cable, and is connected to the grid-side converter through a DC bus, and the grid-side converter is connected to the transformer through a three-phase cable; the turbine generator set is connected to the grid for power generation, and after the turbine generator set is connected to the grid for power generation, the speed of the turbine generator rotor and the speed of the turbine generator magnetic field are monitored, and the speed of the turbine generator rotor is compared with the speed of the turbine generator magnetic field, and the stator and rotor side converters of the turbine generator are controlled; when the turbine generator is connected to the grid When the speed of the turbine generator rotor is greater than the speed of the hydro-generator magnetic field, the stator of the hydro-generator outputs electric energy to the grid through the hydro-generator output line and the transformer, and at the same time, the hydro-generator rotor outputs electric energy to the grid through the rotor-side converter, the DC bus, the grid-side converter, and the transformer; when the speed of the hydro-generator rotor is less than the speed of the hydro-generator magnetic field, the rotor-side converter provides AC excitation to the hydro-generator rotor, and the hydro-generator stator outputs electric energy to the grid through the hydro-generator output line and the transformer; when the speed of the hydro-generator rotor is equal to the speed of the hydro-generator magnetic field, the rotor-side converter provides DC excitation to the hydro-generator rotor, and the hydro-generator stator and the hydro-generator rotor generate electricity synchronously.

[0009] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, wherein: the controller is connected to the rotor side converter, the grid side converter and the online testing device through a data signal line, and the received signal of the controller includes the active power, reactive power and real-time rotation speed of the rotor of the hydro-generator connected to the grid; the online testing device tests the real-time active power and reactive power transmitted by the hydro-generator to the grid bus through a current converter and a voltage converter, and transmits the real-time active power and reactive power to the controller, the controller receives the active power instruction and the reactive power instruction, outputs the voltage instruction and the current instruction to the grid side converter and the rotor side converter, controls the grid side converter and the rotor side converter, and at the same time outputs the opening instruction of the turbine guide vane to control the action of the turbine guide vane actuator, and adjusts the turbine guide vane to the corresponding opening according to the opening instruction.

[0010] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, wherein: the dynamic operation area of ​​the turbine includes a starting grid-connected area, an optimal speed tracking area, a constant speed area and a constant power area; when the turbine water head reaches the starting water head, the system enters the starting grid-connected area, and the turbine guide vane control actuator is used to open the turbine guide vane, and the turbine rotor is turned to the initial speed and grid-connected with initial load operation, preparing to enter the optimal speed tracking area; when the speed of the turbine generator rotor reaches the optimal speed tracking area, the turbine guide vane control actuator is used to operate the turbine guide vane to fully open the turbine guide vane, increase the turbine speed, and perform power control on the unit; obtain the initial value of the optimal active power given value and the current real-time power of the turbine generator, and calculate the power change of the turbine generator; input the power change into the first controller, obtain the turbine generator rotor current given value through the output of the first controller, obtain the turbine generator rotor real-time current, and calculate the generator rotor current The generator rotor current change value is input into the second controller, and the control voltage given value of the turbine generator rotor is obtained through the second controller; the cyclic transmission control is continued, when the turbine generator power change value and the generator rotor current change value are both zero, the unit reaches the optimal active power output, the turbine generator rotor speed is stabilized at a new speed, and the system is ready to enter the constant speed zone operation state; when the speed of the engine rotor enters the constant speed zone, the turbine control power is proportionally controlled by the speed power converter, and the turbine generator rotor speed and the power given value are linearly converted; when the turbine head reaches the fixed speed head and the turbine speed reaches the fixed speed running speed, the turbine continues to maintain the fixed speed running speed, when the turbine head reaches the limited power head and the turbine maintains the fixed speed running speed, the turbine guide vane control actuator is used to operate the opening of the turbine guide vane, adjust the turbine water inlet flow, and stabilize the turbine generator output power at the maximum power.

[0011] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, wherein: the control of the grid-side converter and the rotor-side converter includes the following steps: obtaining the rotor AC voltage and rotor AC current of the unit generator, and decomposing the rotor AC voltage and rotor AC current of the unit generator; calculating and obtaining the active power and reactive power of the generator, and calculating the apparent power of the generator according to the active power and reactive power of the generator; setting the component of the generator rotor AC voltage on the d-axis to zero, obtaining the rotor AC voltage, and respectively calculating the generator unit power control Active power and reactive power of the generator set; respectively control the components of the unit generator rotor AC current on the d-axis and q-axis, and independently decouple the generator active power and reactive power; set the coordinate system of the synchronously rotating grid voltage space vector to the xy coordinate system, and the x-axis of the synchronously rotating xy coordinate system coincides with the grid voltage space vector; calculate the active power and reactive power exchange between the grid-side converter and the grid; control the components of the grid current space vector to respectively control the grid-side converter active power and reactive power, and perform decoupling control of the grid-side converter active power and reactive power.

[0012] As a preferred solution of the unit power control method based on the non-synchronous machine power supply system described in the present invention, the optimization system operating state includes simulating the response characteristics under different working conditions based on the dynamic model of the turbine power control system, collecting historical operating data to predict power control, adjusting control parameters to obtain the optimal control sequence, and adjusting the control sequence according to the deviation between the actual system output and the predicted value.

[0013] In the second aspect, the present invention provides a turbine power control system, which includes: a construction module, used to construct a turbine power control system, and collect system operating parameters in real time through an online testing device; a division module, used to divide the dynamic operating area of ​​the turbine according to the collected real-time operating parameters, and judge the operating area of ​​the unit in combination with the current water head and the real-time operating status of the unit; a control module, used to select and execute corresponding control strategies according to the determined unit operating area, decouple the converter, and optimize the system operating status of the turbine power control.

[0014] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the processor executes the computer program, the steps of a unit power control method based on a non-synchronous machine power supply system are implemented.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, the steps of a method for controlling a unit power based on a non-synchronous power supply system are implemented.

[0016] The beneficial effects of the present invention are that it can better adapt to the environmental water head and always operate at the optimal speed under different water heads, thereby improving the operating efficiency and adaptability of the unit, overcoming the problems that the turbine unit cannot be connected to the grid when operating at a constant speed and the unit cannot operate at the optimal efficiency after the water head changes, and can realize the decoupling control of the active power and reactive power of the generator, and independently control the active power and reactive power of the generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 The figure is a flow chart of a method for controlling the power of a generator set based on a non-synchronous machine power supply system.

[0019] Figure 2 The invention relates to a power control process of a unit power control method based on a non-synchronous machine power supply system. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, 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 them. 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.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example 1

[0024] Reference Figure 1 , which is the first embodiment of the present invention, and provides a method for controlling power of a generator set based on a non-synchronous machine power supply system, comprising:

[0025] S1: Build a turbine power control system and collect system operating parameters in real time through online testing devices;

[0026] Specifically, the turbine power control system includes turbine guide vane control actuator, turbine guide vane, turbine rotor, turbine generator stator, turbine generator rotor, turbine generator output line, transformer, grid bus, grid side converter, DC bus, rotor side converter, controller, online test device and related cables and signal lines.

[0027] The turbine is mainly composed of a turbine rotor and a turbine guide vane. The turbine rotor is rigidly connected to the turbine generator rotor. When the turbine guide vane is opened, water enters the turbine generator rotor to drive the turbine generator rotor to rotate synchronously with the coaxial center. The turbine generator rotor forms a magnetic field after the rotor-side converter applies current. The magnetic field cuts the turbine generator stator as the turbine generator rotor rotates. The turbine generator stator outputs voltage and current through the turbine generator output line, and then transmits electric power to the power grid after the transformer boosts the voltage.

[0028] One end of the rotor-side converter is connected to the turbine generator rotor through a three-phase cable (three-wire or four-wire), and the other end is connected to the grid-side converter through a DC bus. The grid-side converter is connected to the transformer through a three-phase cable (three-wire or four-wire);

[0029] Connect the hydro-turbine generator set to the grid for power generation. After the hydro-turbine generator set is connected to the grid for power generation, monitor the rotation speed of the hydro-turbine generator rotor and the rotation speed of the hydro-turbine generator magnetic field, compare the rotation speed of the hydro-turbine generator rotor with the rotation speed of the hydro-turbine generator magnetic field, and control the converter on the stator and rotor side of the hydro-turbine generator;

[0030] When the speed of the turbine generator rotor is n t When the speed is greater than the magnetic field speed of the hydro-generator, the stator of the hydro-generator outputs electric energy to the grid through the output line of the hydro-generator and the transformer, and the rotor of the hydro-generator outputs electric energy to the grid through the rotor-side converter, DC bus, grid-side converter and transformer;

[0031] When the speed of the turbine generator rotor is n t When the speed is less than the magnetic field speed of the turbine generator, the rotor-side converter provides AC excitation to the turbine generator rotor, and the turbine generator stator outputs electric energy to the grid through the turbine generator outgoing line and transformer;

[0032] When the speed of the turbine generator rotor is n t When it is equal to the magnetic field speed of the turbine generator, the rotor-side converter provides DC excitation to the turbine generator rotor, and the turbine generator stator and the turbine generator rotor function as a synchronous generator set;

[0033] The controller is connected to the rotor-side converter and the grid-side converter through a data signal line. The signal received by the controller is the active power P of the hydro-generator connected to the grid. t , reactive power Q t And the real-time speed n of the turbine generator rotor t ;

[0034] The controller outputs the turbine guide vane opening command y s , opening command y s Control the action of the turbine guide vane actuator so that the turbine guide vane opens according to the opening instruction y s Reach the corresponding opening;

[0035] Controller output command i gs 、u gs Control the current and voltage of the grid-side converter to achieve decoupling control of active and reactive power between the grid-side converter and the grid bus;

[0036] Controller output command i rs 、u rs Control the current and voltage of the rotor-side converter to achieve decoupling control of the active and reactive power of the hydro-generator stator;

[0037] The controller regulates and controls the grid-side converter and the rotor-side converter to achieve active power exchange between the rotor-side converter and the grid bus and maintain the voltage stability of the DC bus.

[0038] Through the controller, the grid-side converter and the rotor-side converter are regulated and controlled to realize the reactive power exchange between the rotor-side converter and the grid bus to achieve the best power factor operation;

[0039] The controller stabilizes the output power frequency of the turbine at 50Hz under variable speed operation, and adjusts the turbine rotor current frequency f2 through the rotor side converter so that where n p is the number of pole pairs of the hydro-generator, thereby ensuring that the stator frequency f1 of the hydro-generator is constant, that is, ensuring that the output power frequency of the hydro-generator set is stable at 50Hz;

[0040] The controller is connected to the online test device through a signal line. The online test device tests the real-time active power P transmitted by the turbine generator to the grid bus through a current converter and a voltage converter. t and reactive power Q t , the real-time active power P t and reactive power Q t Transmitted to the controller; the controller receives the active power instruction P S and reactive power command Q S ; The controller outputs a voltage command i to the grid-side convertergs and current command u gs , the controller outputs a voltage command u to the rotor-side converter rs and current command i rs , to realize the control of the grid-side converter and the rotor-side converter.

[0041] S2: Divide the dynamic operation area of ​​the turbine according to the collected real-time operation parameters, and determine the operation area of ​​the unit in combination with the current water head and the real-time operation status of the unit;

[0042] Specifically, the power control is divided into four areas: the first area is the start-up grid-connected area, the OAB section: the second area is the optimal speed tracking area, the BC section: the third area is the constant speed area, the CD section, and point F is the constant speed point, that is, n max : The 4th area is the constant power area, DE segment.

[0043] Power control is performed. When the turbine head reaches the starting head H min (55m in the embodiment), the system enters the startup grid-connected zone, opens the turbine guide vanes through the turbine guide vane control actuator, and rotates the turbine rotor to the initial speed n min (The embodiment is 5831r / min) The grid is connected and runs with initial load, preparing to enter the optimal speed tracking area;

[0044] When the speed of the turbine generator rotor reaches the optimal speed tracking area, the turbine guide vane control actuator is operated to fully open the turbine guide vane, increase the turbine speed, and control the power of the unit.

[0045] Get the initial value P of the optimal active power given value tmax0 And the current real-time power of the turbine generator, calculate the power change of the turbine generator, the calculation formula is:

[0046] ΔP t =P tmax -P t

[0047] Where ΔP t is the power change, P tmax is the optimal active power given value, P t It is the real-time power of the hydro-generator;

[0048] The power change is input into the first controller, and the given value of the rotor current of the hydro-generator is obtained through the output of the first controller. The real-time rotor current of the hydro-generator is obtained and the rotor current change value of the generator is calculated. The calculation formula is:

[0049] Δi t =i rs -i r

[0050] In the formula, Δi t is the change value of the generator rotor current, i rs is the given value of the rotor current of the turbine generator, i r It is the real-time current of the turbine generator rotor;

[0051] The generator rotor current change value is input into the second controller, and the control voltage given value of the hydro-generator rotor is obtained through the second controller;

[0052] The speed of the turbine generator rotor n t The change leads to the optimal active power given value P tmax The corresponding changes continue to carry out the cycle transfer control. t =0 and Δi t =0, the unit reaches the optimal active power output, stabilizes the rotor speed of the turbine generator at a new speed, and the system is ready to enter the constant speed zone operation state;

[0053] The speed power converter is used to proportionally control the turbine control power and linearly convert the turbine generator rotor speed and power given value; the speed power converter is in proportional control mode to achieve speed n t With power given value P tmax Linear conversion; the first controller and the second controller adopt proportional, integral and differential parallel control mode.

[0054] When the turbine head reaches the constant speed head H nor (138m in the embodiment) and the turbine speed reaches the constant speed n max (9996r / min in the embodiment), the turbine continues to maintain a constant speed, and the active power of the turbine generator increases with the increase of water head;

[0055] When the turbine head reaches the limit power head H max (243m in the embodiment) and the turbine maintains a constant speed n max (In the embodiment, it is 9996r / min), the opening of the turbine guide vanes is operated by the turbine guide vane control actuator to adjust the water inlet flow of the turbine and stabilize the output power of the turbine generator at the maximum power.

[0056] S3: Select and execute the corresponding control strategy according to the determined unit operation area, perform decoupling control on the converter to optimize the system operation state and complete the turbine power control.

[0057] Specifically, the rotor AC voltage and rotor AC current of the generator of the unit are obtained, and the rotor AC voltage and rotor AC current of the generator of the unit are decomposed, and the calculation formula is:

[0058] Vt =U ds +jU qs

[0059] I t =I ds +jI qs

[0060] Where V t is the rotor AC voltage, U ds V is the AC voltage of the generator rotor t On the d-axis, U qs V is the AC voltage of the generator rotor t The component on the q axis; I t is the rotor AC current, I ds is the AC current of the generator rotor I t The component on the d-axis, I qs is the AC current of the generator rotor I t The component on the q axis;

[0061] Calculate the active power and reactive power of the generator, and calculate the apparent power of the generator based on the active power and reactive power of the generator. The calculation formula is:

[0062] P=U ds I ds +U qs I qs

[0063] Q=U qs I ds -U ds I qs

[0064] S=P+jQ

[0065]

[0066] In the formula, S is the apparent power of the generator, P is the active power of the generator, Q and are the reactive power of the generator set. is the rotor AC conjugate current;

[0067] The component of the generator rotor AC voltage on the d-axis is set to zero to obtain the rotor AC voltage. The active power P and reactive power Q of the generator set power control are calculated respectively. The calculation formula is:

[0068] V t =0+jU qs =jU qs

[0069] P=U qs I qs

[0070] Q=U qs I ds

[0071] The components of the alternating current of the generator rotor on the d-axis and q-axis of the unit are controlled respectively, and the active power and reactive power of the generator are independently decoupled and controlled.

[0072] Assume that the grid voltage space vector U g The synchronously rotating coordinate system is the xy coordinate system, that is, the synchronous angular velocity of the xy coordinate system is equal to the angular velocity of the grid voltage, and the x-axis of the synchronously rotating xy coordinate system and the grid voltage space vector U g Overlap, get u gx =U g ,u gy =0;

[0073] The active power and reactive power exchange between the grid-side converter and the grid are calculated. g and reactive power Q g The exchange is determined by the following formula:

[0074]

[0075] Where P g is the active power between the grid-side converter and the grid, Q g is the reactive power between the grid-side converter and the grid, u gx is the component of the grid voltage space vector on the x-axis, u gy is the component of the grid voltage space vector on the y-axis, i gx is the component of the grid current space vector on the x-axis, i gy is the component of the grid current space vector on the y-axis;

[0076] Because u gx =U g ,u gy =0, substituting it into the formula, we get:

[0077]

[0078] In the formula, the grid voltage U g is a constant, indicating the active power P exchanged between the grid-side converter and the grid. g and reactive power Q g Respectively with i gx 、i gy The active power and reactive power of the grid-side converter can be decoupled, that is, by controlling i gx 、i gyThe active power and reactive power of the grid-side converter can be controlled independently, and the voltage of the DC bus can be stably operated by controlling the active power and reactive power of the grid-side converter.

[0079] Based on the dynamic model of the turbine power control system, the response characteristics under different working conditions are simulated, and the historical operation data are collected to build a predictive power control model;

[0080] Define performance indicators, including power output stability, efficiency, and response time, conduct performance evaluation, and adjust control parameters based on the evaluation results;

[0081] Perform power control prediction, build accurate state space models of turbines and converters, and obtain optimal control sequences;

[0082] The time window of rolling optimization is set, and only the first control action is executed each time. After each sampling cycle, the optimal control sequence within the future set time is recalculated, and the control sequence is adjusted according to the deviation between the actual system output and the predicted value.

[0083] Furthermore, this embodiment also provides a turbine power control system, comprising:

[0084] The construction module is used to construct a turbine power control system and collect system operating parameters in real time through an online test device; the division module is used to divide the dynamic operating area of ​​the turbine according to the collected real-time operating parameters, and determine the operating area of ​​the unit in combination with the current water head and the real-time operating status of the unit; the control module is used to select and execute the corresponding control strategy according to the determined unit operating area, decouple the converter, and optimize the operating status of the turbine power control system.

[0085] This embodiment also provides a computer device, which is applicable to the case of a unit power control method based on a non-synchronous machine power supply system, including: 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 all or part of the steps of the method described in the embodiment of the present invention as proposed in the above embodiment.

[0086] This embodiment also provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method in any optional implementation of the above embodiment is executed. Wherein, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, disk or optical disk.

[0087] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0088] From the above, it can be seen that this method is suitable for achieving the power output of the unit under the condition of large changes in water head through variable speed control, can better adapt to the ambient water head, and always operate at the optimal speed under different water heads, thereby improving the operating efficiency and adaptability of the unit, overcoming the technical problems that the turbine unit operating at low water head cannot be connected to the grid when operating at a constant speed and the unit cannot operate at the best efficiency after the water head changes, and can realize the decoupling control of the active power and reactive power of the generator, and independently control the active power and reactive power of the generator respectively.

[0089] Example 2

[0090] Referring to Table 1-Table 2, the second embodiment of the present invention provides a method for controlling the power of a unit based on a non-synchronous machine power supply system. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments. The parameters of the unit are shown in Table 1 for a low-head hydro-generator unit.

[0091] Table 1 Unit parameters

[0092]

[0093] Table 2 Test data table

[0094]

[0095] From the above, it can be seen that this method is suitable for achieving the power output of the unit under the condition of large changes in water head through variable speed control, can better adapt to the ambient water head, and always operate at the optimal speed under different water heads, thereby improving the operating efficiency and adaptability of the unit, overcoming the technical problems that the turbine unit operating at low water head cannot be connected to the grid when operating at a constant speed and the unit cannot operate at the best efficiency after the water head changes, and can realize the decoupling control of the active power and reactive power of the generator, and independently control the active power and reactive power of the generator respectively.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. 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 controlling unit power based on a non-synchronous machine power supply system, characterized in that: include, Build a turbine power control system and collect system operating parameters in real time through online testing devices; Divide the dynamic operation area of ​​the turbine according to the collected real-time operation parameters, and determine the operation area of ​​the unit based on the current water head and the real-time operation status of the unit; According to the determined unit operation area, the corresponding control strategy is selected and executed, the converter is decoupled and controlled, and the unit power control is performed to optimize the system operation status.

2. The method for controlling the power of a generator set based on a non-synchronous power supply system according to claim 1, characterized in that: The water turbine power control system comprises a water turbine guide vane control actuator, a water turbine guide vane, a water turbine rotor, a stator and a rotor of a water turbine generator, a transformer, a grid-side converter, a DC bus, a rotor-side converter and a controller.

3. The method for controlling the power of a generator set based on a non-synchronous power supply system according to claim 2, characterized in that: The turbine comprises a turbine rotor and a turbine guide vane, the turbine rotor is connected to the turbine generator rotor; the rotor-side converter is connected to the turbine generator rotor via a three-phase cable, and is connected to the grid-side converter via a DC bus, and the grid-side converter is connected to the transformer via a three-phase cable; Connect the hydro-turbine generator set to the grid for power generation. After the hydro-turbine generator set is connected to the grid for power generation, monitor the rotation speed of the hydro-turbine generator rotor and the rotation speed of the hydro-turbine generator magnetic field, compare the rotation speed of the hydro-turbine generator rotor with the rotation speed of the hydro-turbine generator magnetic field, and control the converter on the stator and rotor side of the hydro-turbine generator; When the speed of the turbine generator rotor is greater than the speed of the turbine generator magnetic field, the turbine generator stator outputs electric energy to the grid through the turbine generator output line and the transformer, and at the same time, the turbine generator rotor outputs electric energy to the grid through the rotor side converter, the DC bus, the grid side converter and the transformer; When the speed of the turbine generator rotor is less than the speed of the turbine generator magnetic field, the rotor-side converter provides AC excitation to the turbine generator rotor, and the turbine generator stator outputs electrical energy to the grid through the turbine generator outgoing line and transformer; When the speed of the turbine generator rotor is equal to the speed of the turbine generator magnetic field, the rotor-side converter provides DC excitation to the turbine generator rotor, and the turbine generator stator and the turbine generator rotor generate electricity synchronously.

4. The method for controlling the power of a generator set based on a non-synchronous power supply system according to claim 3, characterized in that: The controller is connected to the rotor-side converter, the grid-side converter and the online test device through a data signal line, and the received signal of the controller includes the active power, reactive power and real-time speed of the rotor of the hydro-generator connected to the grid; The online testing device tests the real-time active power and reactive power transmitted by the hydro-generator to the grid bus through a current converter and a voltage converter, and transmits the real-time active power and reactive power to the controller. The controller receives the active power instruction and the reactive power instruction, outputs the voltage instruction and the current instruction to the grid-side converter and the rotor-side converter, controls the grid-side converter and the rotor-side converter, and simultaneously outputs the opening instruction of the turbine guide vane to control the action of the turbine guide vane actuator, so that the turbine guide vane reaches the corresponding opening according to the opening instruction.

5. The method for controlling the power of a generator set based on a non-synchronous machine power supply system according to claim 4, characterized in that: The dynamic operation area of ​​the turbine includes a start-up and grid-connection area, an optimal speed tracking area, a constant speed area, and a constant power area; When the turbine water head reaches the starting water head, the system enters the starting grid-connected area, opens the turbine guide vanes through the turbine guide vane control actuator, and then runs the turbine rotor to the initial speed and grid-connected with initial load, preparing to enter the optimal speed tracking area; When the speed of the turbine generator rotor reaches the optimal speed tracking area, the turbine guide vane control actuator is operated to fully open the turbine guide vane, increase the turbine speed, and control the power of the unit; Obtain the initial value of the optimal active power given value and the current real-time power of the hydro-generator, and calculate the power change of the hydro-generator; The power change is input into the first controller, the given value of the rotor current of the hydro-generator is obtained through the output of the first controller, and the real-time rotor current of the hydro-generator is obtained to calculate the rotor current change value of the generator; The generator rotor current change value is input into the second controller, and the control voltage given value of the hydro-generator rotor is obtained through the second controller; Continue to carry out the cyclic transfer control. When the power change of the turbine generator and the rotor current change of the generator are both zero, the unit reaches the optimal active power output, stabilizes the rotor speed of the turbine generator at the new speed, and the system is ready to enter the constant speed zone operation state; When the speed of the engine rotor enters the constant speed zone, the turbine control power is proportionally controlled through the speed power converter to perform a linear conversion between the turbine generator rotor speed and the power set value; When the turbine head reaches the fixed speed head and the turbine speed reaches the fixed speed operation speed, the turbine continues to maintain the fixed speed operation speed. When the turbine head reaches the limited power head and the turbine maintains the fixed speed operation speed, the turbine guide vane control actuator operates the opening of the turbine guide vane to adjust the turbine water inlet flow and stabilize the output power of the turbine generator at the maximum power.

6. The method for controlling the power of a generator set based on a non-synchronous generator power supply system according to claim 5, characterized in that: The control of the grid-side converter and the rotor-side converter comprises the following steps: Obtaining the rotor AC voltage and rotor AC current of the generator of the unit, and decomposing the rotor AC voltage and rotor AC current of the generator of the unit; Calculate and obtain the active power and reactive power of the generator, and calculate the apparent power of the generator based on the active power and reactive power of the generator; The component of the generator rotor AC voltage on the d-axis is set to zero to obtain the rotor AC voltage, and the active power of the generator set power control and the reactive power of the generator set are calculated respectively; The components of the AC current of the generator rotor on the d-axis and q-axis are controlled respectively, and the active power and reactive power of the generator are independently decoupled and controlled; The coordinate system of the synchronously rotating grid voltage space vector is set as an xy coordinate system, and the x-axis of the synchronously rotating xy coordinate system coincides with the grid voltage space vector; Calculate the active power and reactive power exchange between the grid-side converter and the grid; The components of the grid current space vector are controlled to control the active power and reactive power of the grid-side converter respectively, thereby performing decoupling control of the active power and reactive power of the grid-side converter.

7. The method for controlling the power of a generator set based on a non-synchronous generator power supply system according to claim 6, characterized in that: The optimization system operation state includes simulating the response characteristics under different working conditions based on the dynamic model of the turbine power control system, collecting historical operation data to predict power control, adjusting control parameters to obtain the optimal control sequence, and adjusting the control sequence according to the deviation between the actual system output and the predicted value.

8. A hydro turbine power control system, based on the unit power control method based on a non-synchronous machine power supply system according to any one of claims 1 to 7, characterized in that: include, A construction module is used to construct a turbine power control system and collect system operating parameters in real time through an online test device; The division module is used to divide the dynamic operation area of ​​the turbine according to the collected real-time operation parameters, and determine the operation area of ​​the unit in combination with the current water head and the real-time operation status of the unit; The control module is used to select and execute the corresponding control strategy according to the determined unit operation area, decouple the converter, and perform turbine power control to optimize the system operation status.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the unit power control method based on the non-synchronous machine power supply system according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the unit power control method based on a non-synchronous machine power supply system according to any one of claims 1 to 7 are implemented.

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