Dynamic simulation system of high-capacity variable-speed pumped storage unit

Abstract

The invention relates to a dynamic simulation system of a high-capacity variable-speed pumped storage unit. The dynamic simulation system comprises a simulation generator motor, a simulation pump turbine and the like. The simulation boosting transformer is connected with a power grid and a stator winding of the simulation generator motor, and the motor is mechanically connected with the simulation pump turbine to simulate mechanical rotation characteristics. The pump turbine characteristic simulation and speed regulation system controls and simulates electrical parameters of the pump turbine. The simulation unit alternating-current excitation system is connected with the low-voltage side of the simulation boosting transformer through the simulation current-limiting reactor, and the other end is connected with the simulation generator motor rotor winding to adjust excitation parameters. The joint controller enables the pump turbine characteristic simulation and speed regulation system and the simulation unit alternating current excitation system to work cooperatively. The measurement control and fault simulation system controls on-off of target measurement points and obtains test parameters, and the target measurement points relate to key connection parts of the system. The system can provide test demonstration for the protection principle, the setting method and the protection configuration of the high-capacity variable-speed pumped storage unit.

Description

Technical Field

[0001] This application relates to the technical field of dynamic simulation of power systems, and particularly to a dynamic simulation system for large-capacity variable-speed pumped-storage units. Background Art

[0002] In the process of building a new power system, after a large proportion of new energy is connected to the power grid, problems such as a large random change in power generation power and low fault ride-through ability are prominent, seriously threatening the stable operation and continuous power supply of the power system. Pumped storage has become an important countermeasure. Among them, large-capacity variable-speed pumped-storage units have obvious advantages in achieving efficient regulation through AC excitation.

[0003] However, the research and application of this type of unit are still in its infancy. Due to its large differences in capacity, structure, and operation requirements from similar doubly-fed wind turbines, their experience cannot be borrowed. Moreover, existing commercial power system simulation software cannot simulate internal faults of variable-speed pumped-storage units. The complex stator and rotor winding structures of the units lead to various fault forms, but there is a lack of effective analysis methods.

[0004] Therefore, it is extremely crucial and urgent to develop a dynamic simulation system for large-capacity variable-speed pumped-storage units that can provide support for unit protection, actual engineering fault analysis, testing, etc., to promote the development of the power system. Summary of the Invention

[0005] Based on this, it is necessary to provide a dynamic simulation system for large-capacity variable-speed pumped-storage units in view of the above technical problems.

[0006] In one embodiment, this application provides a dynamic simulation system for large-capacity variable-speed pumped-storage units, including: a simulated generator-motor, a simulated pump-turbine, a simulation of pump-turbine characteristics and its speed regulation system, a simulated unit AC excitation system, a measurement control and fault simulation system, a simulated step-up transformer, a concurrence controller, a simulated current-limiting reactor, where:

[0007] The high-voltage side of the simulated step-up transformer is used to connect to the power grid;

[0008] The stator winding of the simulated generator-motor is electrically connected to the low-voltage side of the simulated step-up transformer, and the simulated generator-motor is also mechanically connected to the simulated pump-turbine through a coupling to simulate the mechanical rotation characteristics of the working process of the large-capacity variable-speed pumped-storage unit;

[0009] The simulation of pump-turbine characteristics and speed regulation system is electrically connected to the simulated pump-turbine and is used to control the electrical parameters of the armature winding and the field winding of the simulated pump-turbine;

[0010] One end of the simulated unit AC excitation system is connected to the low-voltage side of the simulated step-up transformer through a simulated current-limiting reactor, and the other end of the simulated unit AC excitation system is electrically connected to the rotor winding of the simulated motor-generator to adjust the excitation voltage, excitation current, and excitation frequency of the simulated motor-generator;

[0011] The cam controller is respectively connected to the characteristics simulation and speed regulation system of the pump-turbine and the simulated unit AC excitation system to control the characteristics simulation and speed regulation system of the pump-turbine and the simulated unit AC excitation system to work together in a preset mode;

[0012] The measurement control and fault simulation system is used to control the on-off state of the target measurement points to obtain the test parameters of the target measurement points;

[0013] The target measurement points include: each connection end of the simulated motor-generator, each connection end of the simulated unit AC excitation system, the connection path between the characteristics simulation of the pump-turbine and its speed regulation system and the simulated pump-turbine, and each connection end of the simulated step-up transformer.

[0014] In one embodiment, the simulated unit AC excitation system includes: a simulated excitation transformer, an excitation circuit breaker, a converter, and a control and protection system, where,

[0015] The first end of the simulated excitation transformer is connected to the simulated current-limiting reactor through the excitation circuit breaker, and the second end of the simulated excitation transformer is connected to the rotor winding of the simulated motor-generator through the converter;

[0016] The control and protection system is respectively connected to the converter and the cam controller.

[0017] In one embodiment, the simulated unit AC excitation system further includes:

[0018] A contactor provided between the simulated excitation transformer and the converter.

[0019] In one embodiment, the measurement control and fault simulation system includes:

[0020] A first current transformer provided at the stator winding terminal of the simulated motor-generator;

[0021] A second current transformer provided at the rotor winding terminal of the simulated motor-generator;

[0022] A third current transformer and a first voltage transformer provided at the output end of the simulated motor-generator;

[0023] A fourth current transformer provided on the connection path between the simulated unit AC excitation system and the simulated current-limiting reactor;

[0024] The fifth current transformer provided on the connection path between the characteristic simulation of the pump-turbine and its speed regulation system and the simulated pump-turbine;

[0025] The sixth current transformer and the second voltage transformer provided at the low-voltage side terminal of the simulated step-up transformer, and the seventh current transformer and the third voltage transformer provided at the high-voltage side terminal of the simulated step-up transformer.

[0026] In one embodiment, the measurement control and fault simulation system includes a short-circuit switch, a stator breaker, and a commutation switch sequentially provided between the simulated generator-motor and the simulated step-up transformer.

[0027] In one embodiment, the structure of the stator winding and the rotor winding of the simulated generator-motor is the same as that of the large-capacity variable-speed pumped storage unit, the per-unit value of the equivalent circuit electrical parameters of the simulated generator-motor is the same as the per-unit value of the large-capacity variable-speed pumped storage unit, and the speed of the simulated generator-motor is the same as the speed of the generator-motor of the large-capacity variable-speed pumped storage unit.

[0028] In one embodiment, the stator winding of the simulated generator-motor is a double-layer lap winding with 4 branches; the rotor winding of the simulated generator-motor is a double-layer wave winding with 2 branches; and / or, the connection methods of the stator winding and the rotor winding are both Y-type connections.

[0029] In one embodiment, the simulated current-limiting reactor has the same impedance angle as the current-limiting reactor of the large-capacity variable-speed pumped storage unit.

[0030] In one embodiment, the reactance value range of the simulated current-limiting reactor is 2 mH - 7 mH.

[0031] In one embodiment, the dynamic simulation system further includes:

[0032] A fault test panel for setting fault simulation parameters of different types and different positions;

[0033] A wide-band recorder for displaying and recording the electrical parameters of the dynamic simulation system of the large-capacity variable-speed pumped storage unit.

[0034] The above-mentioned dynamic simulation system of the large-capacity variable-speed pumped storage unit has at least the following beneficial effects:

[0035] By simulating the collaborative work of components such as a simulated generator - motor and a simulated pump - turbine, the problem that cannot be tested and verified in an actual dynamic simulation system in the research of relay protection technology for large - capacity variable - speed pumped - storage units is solved. It can provide reliable experimental demonstrations for its protection principle, setting method, and protection configuration. At the same time, it provides a comprehensive and effective tool for fault analysis, operation tests, and protection device tests in actual projects. Moreover, it can realize the full - process dynamic simulation of large - capacity variable - speed pumped - storage units. Not only are physical phenomena presented intuitively, but also the structure is simple, the operation is convenient, and the parameters can be adjusted flexibly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1 FIG. is a schematic structural diagram of a dynamic simulation system for a large - capacity variable - speed pumped - storage unit in an embodiment;

[0038] Figure 2 FIG. is a schematic structural diagram of a dynamic simulation system for a large - capacity variable - speed pumped - storage unit in another embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To facilitate the understanding of the present application, the following will describe the present application more comprehensively with reference to the relevant drawings. Embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0041] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0042] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. can be used herein to describe the relationship of one element or feature shown in the figures with other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device during use and operation. For example, if the device in the attached drawings is flipped, an element or feature described as "under other elements" or "beneath them" or "underneath them" will be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "beneath" can include both upward and downward orientations. In addition, the device may also have other orientations (such as rotated 90 degrees or other orientations), and the spatial descriptors used herein are to be interpreted accordingly.

[0043] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediate element. In addition, in the following embodiments, "connection", if there is a transfer of electrical signals or data between the connected objects, should be understood as "electrical connection", "communication connection", etc.

[0044] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprise / include" or "have" etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0045] In the process of building a new power system, the large-scale access of new energy to the power grid has caused many severe problems. The power generation of new energy shows large-scale random changes, and its fault ride-through ability is poor, which poses a serious threat to the stable operation and continuous power supply of the power system. To address this dilemma, the development and construction process of pumped-storage projects has accelerated. Among them, the large-scale adoption of pumped-storage units, especially large-capacity variable-speed pumped-storage units, has become a highly advantageous solution, which performs excellently in terms of efficiency, cost, safety, pollution and regulation performance. The large-capacity variable-speed pumped-storage unit breaks the limitation of traditional fixed-speed units that are only used for planned peak shaving and frequency modulation by means of AC excitation technology, and can achieve wide-power continuous, efficient and real-time regulation in both power generation and pumping states, providing key support for the stable operation of a new energy-dominated power system.

[0046] However, the current research and application of variable-speed pumped storage units are still in their infancy. Although their power generation state based on AC excitation and double-fed technology is similar to that of double-fed wind turbines, there are significant differences in capacity scale, structural characteristics, and operation requirements compared to double-fed wind turbines, and the production and operation experience of double-fed wind turbines cannot be directly borrowed. To comprehensively grasp their dynamic characteristics under various operating conditions and abnormal states, accurate simulation analysis and system-level dynamic simulation tests are essential.

[0047] However, existing commercial power system transient characteristic simulation software only provides steady-state simulation models for double-fed motors, making it difficult to conduct internal fault simulations for variable-speed pumped storage units. At the same time, due to AC excitation and double-fed structures, the stator and rotor winding structures of variable-speed pumped storage units are complex, with various internal fault forms, and there is a lack of effective analysis methods for internal faults in motor windings.

[0048] For the above reasons, this application provides a dynamic simulation system for large-capacity variable-speed pumped storage units that can provide experimental demonstrations for unit protection principles, setting methods, and protection configurations, and provide a comprehensive and effective tool for fault analysis, operation tests, protection device testing, etc. in actual projects.

[0049] In an exemplary embodiment, as Figure 1As shown in the figure, the present application provides a dynamic simulation system for a large-capacity variable-speed pumped-storage unit, including: a simulated generator-motor 2, a simulated pump-turbine 4, a simulation of the characteristics of the pump-turbine and its speed control system 6, an alternating current excitation system for the simulated unit 8, a measurement control and fault simulation system 10, a simulated step-up transformer 12, a cam controller 14, and a simulated current-limiting reactor 16. Among them: the high-voltage side of the simulated step-up transformer 12 is used to connect to the power grid; the stator winding of the simulated generator-motor 2 is electrically connected to the low-voltage side of the simulated step-up transformer 12, and the simulated generator-motor 2 is also mechanically connected to the simulated pump-turbine 4 through a coupling to simulate the mechanical rotation characteristics during the operation process of the large-capacity variable-speed pumped-storage unit; the simulation of the characteristics of the pump-turbine and its speed control system is electrically connected to the simulated pump-turbine 4 and is used to control the electrical parameters of the armature winding and the excitation winding of the simulated pump-turbine 4; one end of the alternating current excitation system for the simulated unit 8 is connected to the low-voltage side of the simulated step-up transformer 12 through the simulated current-limiting reactor 16, and the other end of the alternating current excitation system for the simulated unit 8 is electrically connected to the rotor winding of the simulated generator-motor 2 to adjust the excitation voltage, excitation current, and excitation frequency of the simulated generator-motor 2; the cam controller 14 is respectively connected to the simulation of the characteristics of the pump-turbine and its speed control system and the alternating current excitation system for the simulated unit 8 to control the simulation of the characteristics of the pump-turbine and its speed control system and the alternating current excitation system for the simulated unit 8 to work in coordination according to a preset mode; the measurement control and fault simulation system 10 is used to control the on-off state of the target measurement points to obtain the test parameters of the target measurement points; the target measurement points include: each connection end of the simulated generator-motor 2, each connection end of the alternating current excitation system for the simulated unit 8, the connection path between the simulation of the characteristics of the pump-turbine and its speed control system and the simulated pump-turbine 4, and each connection end of the simulated step-up transformer 12.

[0050] Among them, the simulated generating motor 2 refers to a simulated double-fed asynchronous unit designed based on a large-capacity variable-speed pumped storage unit in actual application as a prototype. The simulated pump-turbine 4 is a DC motor with low inertia, high mechanical strength, and a wide speed regulation range. Its rotation direction is controlled by the simulation of the pump-turbine characteristics and the speed regulation system, and it can rotate forward or backward. The rotation speed is consistent with the rated speed of the simulated generating motor 2, achieving matching with the generating and pumping conditions of the simulated generating motor 2. The simulation of the pump-turbine characteristics and the speed regulation system uses mathematical modeling methods to finely simulate the operating characteristics of the pump-turbine. It can describe the operating characteristics of the turbine based on its control model, including the simulation of the water hammer effect caused by the water flow inertia in the penstock under the generating condition and the simulation of the pump head under the pumping condition. Secondly, the simulation of the pump-turbine characteristics and the speed regulation system can also achieve power control, torque control, speed control, and opening control of the prime mover. The above-mentioned simulation of the pump-turbine characteristics and the speed regulation system avoids the complex structure, operating conditions, and related mechanical mechanics of the pump-turbine. By controlling the rotation direction and speed of the simulated pump-turbine 4, it can dynamically and accurately simulate the dynamic characteristics of the prototype pumped storage unit under the two conditions of generating and pumping; by changing the fixed value of the transfer function, it can also simulate the prototype variable-speed pumped storage systems of different types and different power levels. The simulated step-up transformer 12 is designed based on the step-up transformer of a large-capacity variable-speed pumped storage unit as a prototype, with a high-quality toroidal core, and has the characteristics of low loss, impact resistance, and high quality. The electrical parameters of the equivalent circuit of the simulated step-up transformer 12, especially the short-circuit impedance parameters, are consistent with the prototype respectively. When internal and external faults of the transformer occur, it ensures that the transient process of the electrical characteristics of the simulated step-up transformer 12 is consistent with the prototype.

[0051] Exemplarily, such as Figure 1As shown in the figure, the simulated generating motor 2 is connected to the 500 kV power grid through a simulated step-up transformer. The simulated generating motor 2 and the simulated pump-turbine 4 are connected by a coupling, and they rotate coaxially to form a counter-driving drive, which is used to simulate the mechanical rotation characteristics of a large-capacity variable-speed pumped-storage unit during the power generation process and the pumping process: Under the power generation condition, the simulated pump-turbine 4 rotates driven by the pump-turbine characteristic simulation and its speed regulation system 6, driving the coaxial simulated generating motor 2 to generate electricity. In this condition, the function of the simulated generating motor 2 is a generator; Under the pumping condition, the simulated generating motor 2 is first frequency-converted and started by the simulated unit AC excitation system 8, and then connected to the 500 kV power grid. It rotates driven by the power grid power supply, driving the simulated pump-turbine 4 to pump water. By adjusting the parameters of the speed regulation system, the pumping power can be adjusted. In this condition, the function of the simulated generating motor 2 is an AC asynchronous motor. The simulated unit AC excitation system 8 is connected to the rotor winding of the simulated generating motor 2, and is used to adjust and control the excitation voltage, excitation current and excitation frequency of the simulated generating motor 2, so as to realize the simulation of the AC excitation system of the prototype unit (i.e., a large-capacity variable-speed pumped-storage unit), and can simulate the control function, control strategy and protection function of the prototype excitation system. Among them, the simulated unit AC excitation system 8 has a variety of control functions: smooth self-start control of the unit, energy feedback braking control (deceleration or shutdown), electric operation mode control (speed and reactive power decoupling control), power generation operation mode control (active and reactive power decoupling control), automatic frequency tracking operation mode control, soft grid connection and soft disconnection (islanding) control, grid fault ride-through control. Among them, the grid fault ride-through control meets the requirements of national standards for the fault ride-through of power electronic devices. The simulated unit AC excitation system 8 also has a variety of control strategies: electric start / feedback braking control strategy, synchronization control and flexible grid connection / islanding control strategy, active / reactive power decoupling control strategy, electric / reactive power decoupling control strategy, fault ride-through control strategy, etc. The main protection functions of the simulated unit AC excitation system 8 include: protection of the grid side of the converter 84, DC side of the converter 84, machine side of the converter 84, control system of the converter 84 and auxiliary equipment. The coordinated controller 14 is connected to the pump-turbine characteristic simulation and speed regulation system and the simulated unit AC excitation system 8 respectively through communication, and is used to control the two systems to work together according to a preset mode, and can simulate various operating conditions of the prototype system (such as power generation condition, power generation phase regulation condition, pumping condition, pumping phase regulation condition) and the automatic conversion between various conditions.

[0052] Under different operating conditions of the simulated large-capacity variable-speed pumped-storage unit, the measurement control and fault simulation system 10 is used to monitor the electrical quantities of each target measurement point and simulate faults, such as measuring the various connection terminals of the simulated generator motor 2, the various connection terminals of the simulated unit AC excitation system 8, the connection path between the characteristics simulation of the pump-turbine and its speed regulation system 6 and the simulated pump-turbine 4, and the various connection terminals of the simulated step-up transformer 12. Among them, the on-off state of the target measurement point can also be controlled (for example, by controlling the tripping and closing of the circuit breaker on the loop) to simulate various types of faults at each fault point. The control accuracy of the switch tripping and closing time is 0.01 ms; internal faults of generators and transformers can be simulated, different branch faults of stators and rotors can be simulated, cross-branch and cross-phase faults of stators and rotors can be simulated, the number of faulty turns can be adjusted, and the minimum turn ratio is less than 5%; arc grounding faults of busbars can be simulated, and various types of grid-connected stability control experiments related to variable-speed pumped-storage units can be simulated.

[0053] The above-mentioned dynamic simulation system of the large-capacity variable-speed pumped-storage unit solves the problem that cannot be tested and verified in the actual dynamic simulation system in the research of the relay protection technology of the large-capacity variable-speed pumped-storage unit by simulating the coordinated work of components such as the simulated generator motor 2 and the simulated pump-turbine 4. It can provide reliable experimental demonstrations for its protection principle, setting method and protection configuration, and at the same time provide a comprehensive and effective tool for fault analysis, operation tests, protection device tests, etc. in actual projects. Moreover, it can realize the dynamic simulation of the whole process of the large-capacity variable-speed pumped-storage unit. Not only are the physical phenomena presented intuitively, but also the structure is simple, the operation is convenient, and the parameters can be adjusted flexibly.

[0054] In an exemplary embodiment, as Figure 2 shown, the simulated unit AC excitation system 8 includes: a simulated excitation transformer 80, an excitation circuit breaker 82, a converter 84 and a control and protection system 86. Among them, the first end of the simulated excitation transformer 80 is connected to the simulated current-limiting reactor 16 through the excitation circuit breaker 82, and the second end of the simulated excitation transformer 80 is connected to the rotor winding of the simulated generator motor 2 through the converter 84; the control and protection system 86 is respectively connected to the converter 84 and the cam controller 14.

[0055] Exemplarily, based on the coordinated operation of the analog excitation transformer 80, excitation breaker 82, and converter 84 of the analog unit AC excitation system 8, the analog unit AC excitation system 8 can achieve control functions such as smooth self-start control of the unit, energy feedback braking control (speed reduction or shutdown), electric operation mode control (speed and reactive power decoupling control), power generation operation mode control (active and reactive power decoupling control), automatic frequency tracking operation mode control, soft grid connection and soft disconnection (islanding) control, grid fault ride-through control, etc. In addition, various control strategies can be realized, such as electric start / feedback braking control strategy, synchronization control and flexible grid connection / islanding control strategy, active / reactive power decoupling control strategy, electric / reactive power decoupling control strategy, fault ride-through control strategy, etc. Secondly, based on the control and protection system 86 of the analog unit AC excitation system 8, under the coordinated action of the coupling controller 14, it can protect the grid side, DC side, machine side, control system and auxiliary equipment of the converter 84.

[0056] In this embodiment, through the coordinated operation of the analog excitation transformer 80, excitation breaker 82, and converter 84, various control functions such as smooth self-start control of the unit, energy feedback braking control, and electric operation mode control are realized, and various control strategies such as electric start / feedback braking control strategy can also be realized, providing comprehensive and flexible control means for the operation of the analog large-capacity variable-speed pumped-storage unit, effectively ensuring the stability and efficiency of the unit operation. At the same time, under the coordinated action of the coupling controller 14, the control and protection system 86 can protect the grid side, DC side, machine side, control system and auxiliary equipment of the converter 84, greatly enhancing the safety and reliability of the system, and providing a solid guarantee for the stable operation of the entire large-capacity variable-speed pumped-storage unit dynamic simulation system.

[0057] In an exemplary embodiment, as Figure 2 shown, the analog unit AC excitation system 8 further includes a contactor 88 disposed between the analog excitation transformer 80 and the converter 84.

[0058] Exemplarily, as Figure 2As shown, the contactor 88 may include KM4, KM5, KM6, and KM7 in the figure. The setting of the contactor 88 further enhances the flexibility and controllability of the AC excitation system 8 of the simulation unit. During the operation of the system, the on-off of the contactor 88 can be controlled to conveniently adjust the circuit connection state between the simulation excitation transformer 80 and the converter 84, so as to more accurately cooperate with the AC excitation system 8 of the simulation unit to achieve various control functions and corresponding control strategies such as smooth self-start control and energy feedback braking control of the unit. At the same time, when an abnormality occurs in the system or maintenance is required, the circuit can be cut off in time, which plays an additional protective role for related equipment such as the grid side, DC side, and machine side of the converter 84, effectively improving the safety, reliability, and operation stability of the entire AC excitation system.

[0059] In an exemplary embodiment, as Figure 2 shown, the measurement control and fault simulation system 10 includes: first current transformers (TA0, TA1, and TA2) provided at the stator winding terminals of the simulation generator motor 2; second current transformers (TAL) provided at the rotor winding terminals of the simulation generator motor 2; third current transformers (TA7) and first voltage transformers (TV7) provided at the output terminals of the simulation generator motor 2; fourth current transformers (TA3) provided on the connection path between the AC excitation system 8 of the simulation unit and the simulation current limiting reactor 16; fifth current transformers (TA6) provided on the connection path between the pump-turbine characteristic simulation and its speed regulation system 6 and the simulation pump-turbine 4; sixth current transformers (TA8) and second voltage transformers (TV8) provided at the low-voltage side terminals of the simulation step-up transformer 12, and seventh current transformers (TA4 and TA9) and third voltage transformers (TV9) provided at the high-voltage side terminals of the simulation step-up transformer 12.

[0060] Exemplarily, the installation positions of each current transformer and each voltage transformer can be referred to Figure 2 as shown, and will not be elaborated here one by one. By setting multiple measurement points in the inter-turn fault branch of the unit, the inter-turn fault branch of the transformer, and the delta winding of the main transformer; when a short-circuit fault occurs in the system, the current transformer has the same transient characteristics as the TPY-class and P-class transformers of the prototype system. When the secondary side is connected to the product under test, the impedance value measured from the primary side meets the requirements, and it has the characteristics of high measurement accuracy and high saturation.

[0061] In this embodiment, by setting up connection paths between the stator winding, rotor winding terminals, and output terminals of the simulated generator-motor 2, between the simulated unit AC excitation system 8 and the simulated current-limiting reactor 16, between the pump-turbine characteristic simulation and its speed regulation system 6 and the simulated pump-turbine 4, and at key positions such as the high- and low-voltage side terminals of the simulated step-up transformer 12, multiple current transformers and voltage transformers are installed, comprehensively covering the key points of the system, such as the inter-turn fault branch of the unit, the inter-turn fault branch of the transformer, and the main transformer delta winding. Cooperating with current transformers that have the same transient characteristics as the prototype system's transformers and feature high measurement accuracy and high saturation characteristics, it can not only accurately measure the electrical quantities at each target measurement point but also effectively simulate various faults when abnormal conditions such as short-circuit faults occur in the system, providing reliable data support and an accurate simulation environment for fault analysis of large-capacity variable-speed pumped-storage units, protection device testing, etc., greatly enhancing the practicality and reliability of the system.

[0062] In an exemplary embodiment, as Figure 2 shown, the measurement control and fault simulation system 10 includes a short-circuit switch 102, a stator circuit breaker 104, and a commutation switch 106 that are sequentially arranged between the simulated generator-motor 2 and the simulated step-up transformer 12.

[0063] Exemplarily, as Figure 2 shown, in addition to the current transformers and voltage transformers at each measurement point, by setting up the short-circuit switch 102, the stator circuit breaker 104, and the commutation switch 106, combined with the current transformers and voltage transformers that are comprehensively arranged at each measurement point, the types of faults that can be simulated are rich. For example, in addition to basic internal and external faults of the unit, it can also simulate faults such as malfunction of the generator terminal circuit breaker, open welding fault inside the winding, and single-phase loss of the excitation system.

[0064] In this embodiment, based on the cooperation between the switches and the current transformers and voltage transformers that are comprehensively arranged at each measurement point, the types of faults that can be simulated are greatly enriched. It can not only simulate common internal and external faults of the unit but also simulate more complex and special fault situations such as malfunction of the generator terminal circuit breaker, open welding fault inside the winding, and single-phase loss of the excitation system, providing a more comprehensive and realistic simulation environment for fault analysis of large-capacity variable-speed pumped-storage units, helping to deeply study the operating characteristics of the unit under different fault scenarios, and thus providing more reliable experimental verification for the protection principle, setting method, and protection configuration of the unit, further enhancing the effectiveness and practicality of the system in aspects such as fault analysis, operation test, and protection device testing in actual projects.

[0065] In an exemplary embodiment, the structures of the stator winding and rotor winding of the simulated generating motor 2 are the same as those of the large-capacity variable-speed pumped storage unit, the per-unit values of the equivalent circuit electrical parameters of the simulated generating motor 2 are the same as the per-unit values of the large-capacity variable-speed pumped storage unit, and the rotational speed of the simulated generating motor 2 is the same as the rotational speed of the generating motor of the large-capacity variable-speed pumped storage unit.

[0066] Exemplarily, the structures of the stator winding and rotor winding of the simulated generating motor 2 are exactly the same as those of the large-capacity variable-speed pumped storage unit, and the per-unit values of its equivalent circuit electrical parameters are also the same as the per-unit values of the large-capacity variable-speed pumped storage unit. In addition, the rotational speed of the simulated generating motor is the same as the rotational speed of the generating motor of the large-capacity variable-speed pumped storage unit, thus ensuring a high degree of similarity in electrical characteristics between the simulated unit and the prototype unit. When a fault occurs in the unit, the electromagnetic transient processes of both can remain consistent, enabling the simulated generating motor 2 to comprehensively and accurately simulate the winding structure of the prototype unit and truly present its mechanical and electrical characteristics. This full-simulation characteristic provides a reliable basis for in-depth study of the various performances of large-capacity variable-speed pumped storage units under normal operation and fault conditions, can provide a more realistic test environment for the research on the protection principle, setting method, and protection configuration of the unit, and further effectively improve the understanding and control ability of large-capacity variable-speed pumped storage units, providing strong support for fault analysis, operation tests, protection device tests, etc. in actual engineering.

[0067] In an exemplary embodiment, as Figure 2 shown, the stator winding of the simulated generating motor 2 is a double-layer lap winding with 4 branches; the rotor winding of the simulated generating motor 2 is a double-layer wave winding with 2 branches; and / or, the connection methods of both the stator winding and the rotor winding are Y-type connections.

[0068] Exemplarily, the stator winding of the simulated generator - motor 2 adopts a double - layer overlapping winding with 4 branches, and the rotor winding adopts a double - layer wave winding with 2 branches. Moreover, both the stator winding and the rotor winding are connected in a Y - type connection. Such a winding structure setting makes the electromagnetic field distribution of the simulated generator - motor 2 highly similar to that of the prototype motor. Since factors such as the winding method, the number of branches, and the connection method of the winding will directly affect the generation and distribution of the electromagnetic field inside the motor, by making the simulated generator - motor 2 consistent with the prototype motor in these key aspects, the electromagnetic characteristics of the prototype motor can be reproduced more realistically. This provides a reliable basis for accurately simulating the operating conditions of a large - capacity variable - speed pumped - storage unit, especially when studying its electromagnetic - related performance and faults. It helps to more deeply understand the operating mechanism of the prototype unit, provides a more accurate reference for the research on the protection principle, setting method, and protection configuration of the unit. At the same time, it also provides a more effective simulation environment for fault analysis, operation tests, and protection device tests in actual engineering.

[0069] In an exemplary embodiment, the simulated current - limiting reactor 16 has the same impedance angle as the current - limiting reactor of the large - capacity variable - speed pumped - storage unit.

[0070] Exemplarily, components such as the simulated generator - motor 2 and the simulated pump - turbine 4 jointly construct a simulation system for the large - capacity variable - speed pumped - storage unit. On this basis, the simulated current - limiting reactor 16 has the same impedance angle as the current - limiting reactor of the large - capacity variable - speed pumped - storage unit. This setting ensures that the simulated current - limiting reactor 16 has excellent linear characteristics. Because the same impedance angle makes the electrical performance of the simulated current - limiting reactor 16 in the circuit similar to that of the prototype current - limiting reactor. During the operation of the system, whether in normal conditions or fault conditions, it can limit and regulate the current in a relatively stable and linear manner, without non - linear changes caused by impedance - angle differences affecting the normal operation of the system and the accuracy of the simulation. This excellent linear characteristic helps to more accurately simulate the actual operating conditions of the large - capacity variable - speed pumped - storage unit, provides more reliable electrical parameters for the measurement and control and fault simulation system 10, enables work such as fault analysis and protection device testing of the unit to be carried out based on a more accurate simulation environment, and thus provides strong support for the research on the protection principle, setting method, and protection configuration of the unit, enhancing the simulation accuracy and reliability of the entire simulation system for the large - capacity variable - speed pumped - storage unit.

[0071] In an exemplary embodiment, the reactance value range of the simulated current - limiting reactor 16 is 2 mH - 7 mH.

[0072] Among them, the reactance value of the model current - limiting reactor can be adjusted within the range of 2 mH to 7 mH to meet the test requirements of different conditions.

[0073] In this embodiment, the reactance value range of the simulated current-limiting reactor 16 is set between 2 mH and 7 mH, and it can be flexibly adjusted within this range of 2 mH to 7 mH. This enables the simulated current-limiting reactor 16 to meet the test requirements under different working conditions. During the operation simulation of a large-capacity variable-speed pumped storage unit, whether in normal power generation, pumping conditions, or various complex fault conditions, by adjusting the reactance value of the simulated current-limiting reactor 16, different circuit impedance conditions can be simulated, more realistically reproducing the electrical characteristics of the prototype unit under different working conditions. This provides a diverse test environment for the measurement control and fault simulation system 10, helps to more comprehensively and deeply study the operation characteristics and fault response mechanisms of the unit, and thus provides richer and more accurate data support for the research of unit protection principles, setting methods, and protection configurations, greatly enhancing the practicality and adaptability of the entire simulation system, and strengthening the simulation ability and fault analysis ability for various working conditions of large-capacity variable-speed pumped storage units.

[0074] In an exemplary embodiment, as Figure 2 shown, the dynamic simulation system further includes a fault test panel 18 and a broadband recorder 20. The fault test panel 18 is used to set fault simulation parameters of different types and different positions; the broadband recorder 20 is used to display and record the electrical parameters of the dynamic simulation system of the large-capacity variable-speed pumped storage unit.

[0075] Among them, the fault simulation parameters refer to the relevant parameters set on the fault test panel 18 for simulating different types (such as generator breaker failure, internal winding open welding fault, excitation system single-phase fault, etc.) and different positions (such as unit turn-to-turn fault branch, transformer turn-to-turn fault branch, main transformer delta winding, etc.) of faults of the large-capacity variable-speed pumped storage unit.

[0076] Exemplarily, the fault test panel 18 can set fault simulation parameters of different types and different positions, making the fault simulation of the large-capacity variable-speed pumped storage unit more flexible, diverse, and accurate, and comprehensively simulating various possible fault situations. The broadband recorder 20 is used to display and record the electrical parameters of the dynamic simulation system, and can capture the changes in electrical characteristics of the system during normal operation and fault states in real time and accurately. The two cooperate with components such as the simulated generator motor 2 and the simulated current-limiting reactor 16 to jointly construct the dynamic simulation system of the large-capacity variable-speed pumped storage unit. On the one hand, diverse fault simulations can be achieved through the parameters set by the fault test panel 18, providing rich test scenarios for in-depth study of the unit's fault response mechanism; on the other hand, the electrical parameters recorded by the broadband recorder 20 provide reliable data support for the research of unit protection principles, setting methods, and protection configurations, helping to more accurately analyze the cause of faults, evaluate the performance of protection devices, and enhance the practicality and effectiveness of the entire simulation system in actual engineering applications.

[0077] In the description of this specification, the descriptions referring to terms such as "some embodiments", "other embodiments", "ideal embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0078] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0079] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A dynamic simulation system for a large-capacity variable-speed pumped storage unit, characterized in that: include: Simulated generator motor, simulated pump turbine, pump turbine characteristic simulation and speed control system, simulated unit AC excitation system, measurement control and fault simulation system, simulated step-up transformer, cooperative controller, simulated current limiting reactor, including: The high voltage side of the simulated step-up transformer is used to access the power grid; The stator winding of the simulated generator motor is electrically connected to the low-voltage side of the simulated step-up transformer, and the simulated generator motor is also mechanically connected to the simulated water pump turbine through a coupling to simulate the mechanical rotation characteristics of the working process of the large-capacity variable-speed pumped-storage unit; The pump-turbine characteristic simulation and speed regulation system is electrically connected to the simulated pump-turbine and is used to control the electrical parameters of the armature winding and the field winding of the simulated pump-turbine; One end of the simulated unit AC excitation system is connected to the low voltage side of the simulated step-up transformer through the simulated current limiting reactor, and the other end of the simulated unit AC excitation system is electrically connected to the rotor winding of the simulated generator motor to adjust the excitation voltage, excitation current and excitation frequency of the simulated generator motor; The cooperative controller is respectively connected to the pump-turbine characteristic simulation and speed regulation system and the simulated unit AC excitation system to control the pump-turbine characteristic simulation and speed regulation system and the simulated unit AC excitation system to work in coordination according to a preset mode; The measurement control and fault simulation system is used to control the on / off state of the target measurement point to obtain the test parameters of the target measurement point; The target measurement points include: various connection ends of the simulated generator motor, various connection ends of the simulated unit AC excitation system, the connection path between the pump-turbine characteristic simulation and its speed control system and the simulated pump-turbine, and various connection ends of the simulated step-up transformer.

2. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 1 is characterized in that: The simulated unit AC excitation system includes: a simulated excitation transformer, an excitation circuit breaker, a converter and a control and protection system, wherein: The first end of the simulated excitation transformer is connected to the simulated current limiting reactor through the excitation circuit breaker, and the second end of the simulated excitation transformer is connected to the rotor winding of the simulated generator motor through the converter; The control and protection system is connected to the converter and the cooperative controller respectively.

3. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 2 is characterized in that: The simulated unit AC excitation system also includes: A contactor is provided between the simulated excitation transformer and the converter.

4. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 1 is characterized in that: The measurement control and fault simulation system comprises: A first current transformer provided at a stator winding connection terminal of the simulated generator motor; A second current transformer provided at the rotor winding connection terminal of the simulated generator motor; a third current transformer and a first voltage transformer provided at the output end of the simulated generator motor; A fourth current transformer provided on a connection path between the simulated unit AC excitation system and the simulated current limiting reactor; A fifth current transformer provided on the connection path between the pump-turbine characteristic simulation and speed regulation system and the simulated pump-turbine; A sixth current transformer and a second voltage transformer are arranged at the low-voltage side connection terminal of the simulated step-up transformer, and a seventh current transformer and a third voltage transformer are arranged at the high-voltage side connection terminal of the simulated step-up transformer.

5. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 4 is characterized in that: The measurement control and fault simulation system comprises a short-circuit switch, a stator circuit breaker and a reversing switch which are sequentially arranged between the simulated generator motor and the simulated step-up transformer.

6. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 1 is characterized in that: The structure of the stator winding and rotor winding of the simulated generator motor is consistent with the structure of the large-capacity variable-speed pumped-storage unit, the per-unit value of the equivalent circuit electrical parameters of the simulated generator motor is consistent with the per-unit value of the large-capacity variable-speed pumped-storage unit, and the rotational speed of the simulated generator motor is consistent with the rotational speed of the generator motor of the large-capacity variable-speed pumped-storage unit.

7. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 6 is characterized in that: The stator winding of the simulated generator motor is double-layer stacked and has 4 branches; the rotor winding of the simulated generator motor is double-layer wave wound and has 2 branches; and / or the stator winding and the rotor winding are both connected in Y-type connection.

8. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 1 is characterized in that: The simulated current limiting reactor has the same impedance angle as the current limiting reactor of the large-capacity variable-speed pumped-storage unit.

9. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 8 is characterized in that: The reactance value range of the simulated current limiting reactor is 2mH-7mH.

10. The dynamic simulation system of the large-capacity variable-speed pumped-storage unit according to claim 1, characterized in that: The dynamic simulation system also includes: Fault test screen, used to set fault simulation parameters of different types and locations; A wideband recorder is used to display and record the electrical parameters of the dynamic simulation system of the large-capacity variable-speed pumped-storage unit.

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