A method for active control of virtual inertia of a phase modulator system

Abstract

The present application belongs to the technical field of phase modifier, and discloses a kind of active control method of virtual inertia of phase modifier system, comprising: obtaining the real-time frequency of power grid and the real-time operating parameter of phase modifier system;Based on the frequency deviation of power grid real-time frequency and power grid rated frequency, the frequency variation rate and the frequency deviation change rate are comprehensively considered, and the rotor angular velocity reference value is calculated;Based on real-time operating parameter and rotor angular velocity reference value, the rotor side converter adjusts rotor angular velocity, to realize the active control of virtual inertia.By comprehensively considering the frequency deviation, frequency variation rate and frequency deviation change rate, active and comprehensive control of virtual inertia is realized, compared with traditional passive response, the method provided by the present application can more accurately perceive the severity and evolution trend of power grid disturbance, thereby providing more matched active support.

Description

Technical Field

[0001] This invention belongs to the field of camera adjustment technology, specifically relating to a method for active virtual inertia control of a camera adjustment system. Background Technology

[0002] Synchronous condensers, with their fast reactive power response and strong overload capacity, have become key equipment for ensuring the sustainable development of new energy sources. Traditional synchronous condensers use DC excitation and can only operate in synchronous mode. Their excitation system is relatively simple and has few control dimensions, only able to control the magnitude of the excitation current to adjust reactive power.

[0003] The asynchronous synchronous condenser borrows the operating principle of a doubly-fed induction generator (DFIG) and is matched with a vector control system for rotor AC excitation. It possesses asynchronous operation capability and can actively adjust its speed. Its excellent variable-speed operation characteristics allow the asynchronous condenser to provide a certain amount of inertia support to the system during transients, and it can also achieve decoupled control of speed and reactive power. Furthermore, because the rotor magnetic field position is controllable, the asynchronous condenser also has stronger phase-leading capability. Given its operational flexibility and controllability, the asynchronous condenser possesses the dual characteristics of both synchronous and asynchronous motors, hence it is also called an asynchronous synchronous condenser.

[0004] High-inertia flywheel energy storage type asynchronous synchronous condenser combines flywheel energy storage and synchronous condenser in power systems. The stator three-phase windings of the motor are directly connected to the grid, and the rotor three-phase windings are AC excited through a back-to-back converter. The motor rotor is connected to a flywheel device to increase rotor inertia, thereby providing active power support by releasing flywheel kinetic energy when the system frequency drops. Therefore, the flywheel energy storage type asynchronous synchronous condenser enhances the level of system safety operation while also providing voltage and frequency support capabilities.

[0005] Because synchronous condensers lack a prime mover to provide input mechanical power, constant speed control is required to maintain normal phasing operation in steady state. Therefore, existing synchronous condensers operate in two modes: inertial support based on active power control and standby operation based on steady-state constant speed control. However, there are many problems in the connection and coordination between these two modes, making it difficult to achieve good operating results. Furthermore, most synchronous condensers simulate the inertial response characteristics of synchronous machines from the perspective of the active power response system frequency change rate, without considering the coupling law between rotor speed and grid frequency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for active virtual inertia control of a synchronous condenser system. By comprehensively considering frequency deviation, frequency change rate, and frequency deviation change rate, it achieves active and comprehensive control of virtual inertia. Compared with traditional passive response, the method provided by this invention can more accurately perceive the severity and evolution trend of power grid disturbances, thereby providing more suitable active power support.

[0007] This invention provides the following technical solution: A method for active virtual inertia control of a camera shifting system, characterized by comprising: Obtain the real-time frequency of the power grid and the real-time operating parameters of the synchronous condenser system; Based on the frequency deviation between the real-time frequency of the power grid and the rated frequency of the power grid, and taking into account both the frequency change rate and the frequency deviation change rate, the reference value of the rotor angular velocity is calculated. Based on real-time operating parameters and rotor angular velocity reference values, the rotor-side converter is controlled to adjust the rotor angular velocity in order to achieve active control of virtual inertia.

[0008] As a further improvement of the present invention, the synchronous condenser system includes an asynchronous synchronous condenser, a flywheel device, a back-to-back converter, a main transformer, an excitation transformer, and a power grid. The rotor of the asynchronous synchronous condenser is connected to the rotor of the flywheel device, the stator of the asynchronous synchronous condenser is connected to the power grid through the main transformer, and the rotor of the asynchronous synchronous condenser is connected to the power grid through the excitation transformer and the back-to-back converter.

[0009] As a further improvement of the present invention, the rotor angular velocity reference value is the sum of the rotor angular velocity, frequency deviation term, and differential term corresponding to the rated frequency of the power grid, and a droop coefficient for controlling the frequency deviation term and a differential coefficient for controlling the differential term are introduced; wherein, the differential term is composed of the power grid frequency change rate and the power grid frequency deviation change rate.

[0010] By decomposing the speed reference value into a rated term, a droop term, and a double differential term, multi-dimensional frequency support is achieved. The droop term ensures consistent evolution between speed and frequency, while the double differential term significantly enhances the system's instantaneous hard support capability in the early stages of frequency fluctuations.

[0011] As a further improvement of the present invention, a weighting factor is introduced into the differential term to dynamically adjust the contribution of the power grid frequency change rate and the power grid frequency deviation change rate, wherein the weighting factor is in the range of [0,1].

[0012] The contradiction between response speed and negative damping in virtual inertia control is resolved by introducing a weighting factor. By dynamically adjusting the contributions of the two types of rates of change, the system can quickly suppress frequency drops during disturbances and avoid frequency oscillations caused by single derivative control, thereby improving the system's regulation capability.

[0013] As a further improvement of the present invention, based on real-time operating parameters and rotor angular velocity reference values, dual outer loop control, current inner loop control and space voltage vector pulse width modulation are used to control the rotor-side converter to adjust the rotor angular velocity.

[0014] As a further improvement of the present invention, the dual outer loop control includes frequency-speed droop outer loop control and reactive power outer loop control; wherein, the frequency-speed droop outer loop control generates a reference value for the active component of the rotor current using a regulator based on the rotor angular velocity reference value and the real-time value of the rotor angular velocity; the reactive power outer loop control generates a reference value for the reactive component of the rotor current using a regulator based on the stator reactive power reference value and the real-time value of the stator reactive power.

[0015] This achieves complete decoupling control between reactive power and rotor speed (active power). The synchronous condenser provides inertia support and suppresses frequency fluctuations without affecting its voltage regulation and reactive power compensation functions, ensuring dual stability of grid voltage and frequency. As a further improvement of the present invention, the current inner loop control is based on the reference values ​​of the active and reactive components of the rotor current and the real-time values ​​of the active and reactive components, and the regulator generates rotor voltage commands.

[0016] As a further improvement of the present invention, space voltage vector pulse width modulation generates the duty cycle or operating time of each power switching device of the rotor-side converter based on the rotor voltage command, so as to control the rotor-side converter to adjust the rotor angular velocity.

[0017] As a further improvement of the present invention, it also includes: after the support control of the equivalent virtual inertia provided by the camera focusing system ends, the rotor angular velocity of the camera focusing system is adaptively restored.

[0018] As a further improvement of the present invention, the rotor speed adaptive recovery of the synchronous condenser system includes: When the power grid is in the first frequency regulation stage after the equivalent virtual inertia support control ends, there is a steady-state frequency deviation between the real-time frequency of the power grid and the rated frequency of the power grid. The rotor angular velocity of the control synchronous condenser system is stabilized at the angular velocity corresponding to the real-time power grid frequency. When the power grid is in the secondary frequency regulation stage after the equivalent virtual inertia support control ends, the real-time frequency of the power grid gradually returns to the rated frequency of the power grid. The synchronous condenser system responds to the change in the power grid frequency, and the rotor angular velocity recovers to the angular velocity corresponding to the rated frequency of the power grid.

[0019] This solves the problem of speed return after inertia support ends, preventing the flywheel from losing its subsequent support capability due to energy depletion or persistently low speed, and ensuring the system's sustainability in coping with multiple consecutive disturbances. Compared with the prior art, the beneficial effects of the present invention are as follows: By comprehensively considering frequency deviation, frequency change rate, and frequency deviation change rate, active and comprehensive control of virtual inertia is achieved. Compared with traditional passive response, the method provided by this invention can more accurately perceive the severity and evolution trend of power grid disturbances, thereby providing more suitable active power support.

[0020] Compared to the inertia support method of traditional active control mode, the frequency-speed droop control method proposed in this invention does not require switching of operating models and can achieve multiple functions such as steady-state constant speed operation, transient inertia support and speed self-recovery in speed operation mode alone.

[0021] The differential term in the grid frequency stage considers both the rate of change of grid frequency and the rate of change of grid frequency deviation. This allows for rapid inertia support and eliminates the negative damping problem that can occur if only the rate of change of grid frequency is considered. Furthermore, a weighting factor is introduced in the grid frequency differential term to balance the contributions of both the rate of change of grid frequency and the rate of change of grid frequency deviation to system inertia support. Rapid response inertia support increases the weight of the rate of change of grid frequency, while eliminating the residual of steady-state frequency increases the weight of the rate of change of grid frequency deviation. Attached Figure Description

[0022] Figure 1 A schematic diagram of a flywheel energy storage type asynchronous synchronous condenser system; Figure 2 The control block diagram for the virtual inertia support control method of the camera system.

[0023] Explanation of reference numerals in the attached diagram: 1. Energy storage type synchronous condenser; 2. Back-to-back converter; 3. Power grid; 4. Main transformer; 5. Excitation transformer; 6. Asynchronous synchronous condenser; 7. Flywheel device; 8. Grid-side converter; 9. Rotor-side converter; 10. Energy storage capacitor. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings: This embodiment provides a method for active virtual inertia control of a synchronous condenser system. The synchronous condenser system is a flywheel energy storage type asynchronous synchronous condenser system, with the structure as follows: Figure 1As shown, the flywheel energy storage type asynchronous synchronous condenser system includes an energy storage synchronous condenser 1, a back-to-back converter 2, a transformer, and a power grid 3. The energy storage synchronous condenser 1 consists of an asynchronous synchronous condenser 6 and a flywheel device 7. The asynchronous synchronous condenser 6 has the same structure as a traditional doubly-fed induction motor, with three-phase power windings on its stator and three-phase excitation windings on its rotor. The rotor of the asynchronous synchronous condenser 6 is directly connected to the rotor of the flywheel device 7. The back-to-back converter 2 consists of a rotor-side converter 9 and a grid-side converter 8. Both the rotor-side converter 9 and the grid-side converter 8 are three-phase inverters, and an energy storage capacitor 10 is arranged on the DC bus between them. There are two transformers: one is the main transformer 4, and the other is the excitation transformer. Transformer 5; The three-phase power windings on the stator of the asynchronous synchronous condenser 6 are connected to the power grid 3 via the main transformer 4, and the three-phase excitation windings on its rotor are connected to the main transformer 4 via the excitation transformer 5; The flywheel device 7 is equipped with a large-diameter, high-weight rotor to increase the moment of inertia and provide more rotor energy storage to the power grid under a wide speed range; The grid-side converter 8 is used to maintain the DC bus voltage stability, while the rotor-side converter 9 is used to realize AC excitation control to achieve decoupling control of reactive and active power at the stator port of the asynchronous synchronous condenser 6, thereby providing the ability to support the transient voltage and frequency of the power grid.

[0026] The method includes: Obtain the real-time frequency of the power grid and the real-time operating parameters of the synchronous condenser system; Based on the frequency deviation between the real-time frequency of the power grid and the rated frequency of the power grid, and taking into account both the rate of change of the power grid frequency and the rate of change of the frequency deviation, the reference value of the rotor angular velocity of the synchronous condenser system is calculated. Based on real-time operating parameters and rotor angular velocity reference values, outer loop control, inner current control, and space voltage vector pulse width modulation are used to control the rotor-side converter to adjust the rotor angular velocity, thereby achieving support control of the virtual inertia of the camera system.

[0027] The method provided in this embodiment is only used for the control of the rotor-side converter, and is used to realize the active control of the virtual inertia of the synchronous condenser system. The specific control flow is as follows: Figure 2 As shown. The outer loop consists of reactive power outer loop control and frequency-speed droop outer loop control. The frequency-speed droop outer loop control adjusts the rotor speed of the synchronous condenser system proportional to the deviation between the grid frequency and the rated frequency, ensuring that the speed change matches the grid frequency change, thus maintaining the constant speed operation of the synchronous condenser system when the grid frequency is stable. Additionally, to improve the inertial response speed in the initial stage of frequency disturbances, two differential elements—frequency and frequency change—are added, and a weighting factor is introduced to quickly reduce the grid frequency change rate and eliminate the negative damping problem caused by the frequency change rate. The following is combined with... Figure 2 The specific process of the method is explained.

[0028] Step A: Collect parameters such as voltage, current, and rotation speed of the asynchronous phase shifter, and perform relevant calculations; Step A-1: ​​Collect the phase voltage of the three-phase power winding of the synchronous condenser. U s,abc ,based on U s,abc Calculating the angular velocity of the synchronous rotating magnetic field of the phase-locked loop (PLL) condenser stator oh PLL Then, the position angle of the synchronous rotating magnetic field of the phase-converter stator is obtained by integral calculation. i PLL ; Step A-2, according to U s,abc After performing Clarke and Park transformations sequentially, the q-axis stator voltage is obtained. u sq and d-axis stator voltage u sd ; Step A-3: Collect the phase current of the three-phase power winding of the synchronous condenser. i s,abc After performing Clarke and Park transformations sequentially, the real-time value of the q-axis stator current is obtained. i sq and d-axis stator current real-time value i sd ; Step A-4: Based on the calculation results of steps A-2 and A-3, obtain the active power output of the synchronous condenser stator. P s and reactive power Q s The calculation formula is: and ; Step A-5: Collect the angular velocity of the synchronous condenser rotor. oh r Then, the rotor position angle is obtained by integration. i r ; Step A-6: Calculate the slip angle of the synchronous condenser rotor. i The calculation formula is: i = i PLL - i r ; Step A-7: Collect the phase current of the three-phase excitation winding of the synchronous condenser. i r,abc First, a Clarke transformation is performed to obtain the real-time value of the α-axis rotor current. i rα Real-time value of β-axis rotor currenti rβ Then, the Park transformation is performed to obtain the real-time value of the q-axis rotor current. i rq and d-axis rotor current real-time value i rd ; Step B: Calculate the reference value of the angular velocity of the synchronous condenser rotor. oh r,ref ; Step B-1: Acquire real-time power grid frequency f According to the rated power grid frequency f 0, for the rated frequency of my country's power grid f 0 = 50Hz, obtain the frequency change Δ f The calculation formula is △ f = f - f 0; Step B-2: Establish the relationship between the synchronous condenser rotor speed and the power grid frequency, and design a reference value for the angular velocity of the synchronous condenser rotor. oh r,ref Real-time frequency of the power grid f Rated frequency of power grid f 0 and the change in grid frequency Δ f The relationship between them is used to calculate the reference value of the rotor's angular velocity. oh r,ref The calculation formula is:

[0029] in, oh r0 The steady angular velocity of the rotor at the rated frequency of the power grid. k 1 is the droop coefficient and k 1>0, k 2 is the differential coefficient and k 2>0, k 3 is a weighting factor and 0 ≤ k 3≤1; Step C involves performing reactive power outer loop control and frequency-speed droop outer loop control respectively. Step C-1, adjust the reference value of the phase shifter stator reactive power. Q s,ref Subtract the reactive power calculated in step A-4 Q s Then, the reference value of the q-axis rotor current of the synchronous condenser is obtained through a proportional-integral (PI) regulator. i rq,ref ; The rotor angular velocity reference values ​​calculated in steps C-2 and B-2 oh r,refSubtract the real-time rotor angular velocity value obtained in step A-4 oh r Then, the reference value of the d-axis rotor current of the synchronous condenser is obtained through a PI regulator. i rd,ref ; Step D, current inner loop control and space voltage vector pulse width modulation (SVPWM). Step D-1, Inner current loop control; q-axis rotor current reference value i rq,ref Subtract the real-time value of the q-axis rotor current i rq Then, through a PI controller, the q-axis rotor voltage of the synchronous condenser is obtained. u sq d-axis rotor current reference value i rd,ref Subtract the real-time value of the d-axis rotor current i rd Then, through a PI regulator, the d-axis rotor voltage of the synchronous condenser is obtained. u sd ; Step D-2, SVPWM control; q-axis rotor voltage u sq d-axis rotor voltage u sd The α-axis rotor voltage was obtained by inverse Park transformation. u rα and β-axis rotor voltage u rβ Based on traditional SVPWM technology, the α-axis rotor voltage... u rα and β-axis rotor voltage u rβ Calculate the duty cycle or operating time of the six power switches in the three arms of the rotor-side converter; achieve closed-loop control of the three-phase excitation winding current by adjusting the voltage applied to the three-phase excitation winding in real time, thereby achieving speed, reactive power and active power control of the synchronous condenser. Step E: Inertia support control of the asynchronous synchronous phase shifter system; Step E-1, the virtual inertia equivalence principle of asynchronous synchronous condenser systems; the transient frequency support capability of flywheel energy storage type asynchronous synchronous condensers is reflected by the inertia of their rotor rotation. Unlike the inherent mechanical inertia characteristics of synchronous machines, the inertia provided to the grid by flywheel energy storage type asynchronous synchronous condensers becomes an equivalent virtual inertia simulated by the control of the rotor-side converter. Therefore, when the rotational speed of the flywheel energy storage type asynchronous synchronous condenser changes, the actual kinetic energy change of its rotor is equal to the kinetic energy change of the equivalent synchronous unit under virtual inertia, thus yielding... ; where Δ EThis represents the change in rotor kinetic energy of the energy storage type synchronous condenser. oh r1 Let Δ be the initial angular velocity of the energy storage type synchronous condenser. oh r This represents the change in angular velocity of the energy storage type synchronous condenser. J r The inherent inertia of the energy storage type synchronous condenser. J eq For equivalent virtual inertia, oh s1 Let Δ be the initial angular velocity of the equivalent synchronous machine. oh s This is the change in angular velocity of the equivalent synchronous machine, used to characterize changes in grid frequency; Step E-2, Asynchronous conversion of the equivalent virtual inertia of the synchronous camera system J eq Calculation: Based on the virtual inertia equivalence principle in step E-1, the equivalent virtual inertia can be calculated. J eq ,Right now It can be seen that the equivalent virtual inertia of the flywheel energy storage type asynchronous synchronous condenser is related to the frequency-speed change relationship, the operating point and the inherent inertia. Therefore, when the grid frequency is disturbed, the rotor speed of the energy storage type synchronous condenser can be adjusted, thereby generating an inertial response that changes in the same direction as the grid frequency. Step E-3: When the power grid system is subjected to unbalanced active power disturbances, which cause fluctuations in the power grid frequency, the power grid frequency is monitored in real time. f Combined with the rated frequency of the power grid f 0, the change in power grid frequency Δ can be calculated. f The rate of change of the power grid frequency is further obtained through differential calculation. and the rate of change of power grid frequency And based on the reference value of the rotor angular velocity of the energy storage type synchronous condenser calculated in step B-2 oh r,ref Reasonable design k 1. k 2. k The three coefficients, namely 3, can be used to adjust the active power of the synchronous condenser through frequency-speed droop control, thereby eliminating grid frequency fluctuations and providing inertia support for the grid. When the grid frequency fluctuates, the energy storage synchronous condenser has two operating states: Status 1: oh r < oh r0 , and At this time, the grid frequency drops, the flywheel energy storage device releases the rotor kinetic energy, the energy storage type synchronous condenser operates in the power generation state, outputs active power to the grid, suppresses the decrease of grid frequency, and thus achieves frequency support for the grid. State Two: oh r > oh r0 , and At this time, the grid frequency increases, the flywheel energy storage device absorbs the rotor kinetic energy, the energy storage type synchronous condenser operates in the energy storage state, absorbs active power from the grid, suppresses the increase of grid frequency, and thus achieves frequency support for the grid; Step F: Self-recovery control of the rotation speed of the energy storage type synchronous condenser; Step F-1: In the first frequency regulation stage after the inertia support control shown in step E ends, there is a certain steady-state frequency deviation between the real-time frequency of the power grid and its rated frequency. Frequency-speed droop control is continued to be used to stabilize the energy storage synchronous condenser at the speed corresponding to the frequency, so as to avoid further release of rotor kinetic energy. Step F-2: After the energy storage-type synchronous condenser operates in the state shown in step F-1, the power grid will enter the secondary frequency regulation stage, and the power grid frequency will gradually return to its rated frequency. f At value 0, the energy storage synchronous condenser responds again to the grid frequency change, restoring its rotational speed to steady-state speed. The corresponding angular velocity at this point becomes... oh r0 .

[0030] In summary, by using the above methods, energy storage synchronous condensers can achieve multiple functions such as steady-state constant speed operation, transient inertia support, and speed self-recovery.

[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for active virtual inertia control of a camera adjustment system, characterized in that, include: Obtain the real-time frequency of the power grid and the real-time operating parameters of the synchronous condenser system; Based on the frequency deviation between the real-time frequency of the power grid and the rated frequency of the power grid, and taking into account both the frequency change rate and the frequency deviation change rate, the reference value of the rotor angular velocity is calculated. Based on real-time operating parameters and rotor angular velocity reference values, the rotor-side converter is controlled to adjust the rotor angular velocity in order to achieve active control of virtual inertia.

2. The method according to claim 1, characterized in that, The synchronous condenser system includes an asynchronous synchronous condenser, a flywheel device, a back-to-back converter, a main transformer, an excitation transformer, and a power grid. The rotor of the asynchronous synchronous condenser is connected to the rotor of the flywheel device, the stator of the asynchronous synchronous condenser is connected to the power grid through the main transformer, and the rotor of the asynchronous synchronous condenser is connected to the power grid through the excitation transformer and the back-to-back converter.

3. The method according to claim 1, characterized in that, The rotor angular velocity reference value is the sum of the rotor angular velocity corresponding to the rated frequency of the power grid, the frequency deviation term, and the differential term. A droop coefficient for controlling the frequency deviation term and a differential coefficient for controlling the differential term are introduced. The differential term consists of the rate of change of the power grid frequency and the rate of change of the power grid frequency deviation.

4. The method according to claim 3, characterized in that, A weighting factor is introduced into the differential term to dynamically adjust the contribution of the power grid frequency change rate and the power grid frequency deviation change rate, wherein the weighting factor ranges from [0,1].

5. The method according to claim 1, characterized in that, Based on real-time operating parameters and rotor angular velocity reference values, the rotor-side converter is controlled to adjust the rotor angular velocity using dual outer loop control, current inner loop control, and space voltage vector pulse width modulation.

6. The method according to claim 5, characterized in that, The dual outer loop control includes frequency-speed droop outer loop control and reactive power outer loop control; wherein, the frequency-speed droop outer loop control generates a reference value for the active component of the rotor current using a regulator based on the rotor angular velocity reference value and the real-time value of the rotor angular velocity; the reactive power outer loop control generates a reference value for the reactive component of the rotor current using a regulator based on the stator reactive power reference value and the real-time value of the stator reactive power.

7. The method according to claim 6, characterized in that, The current inner loop control is based on the reference values ​​of the active and reactive components of the rotor current, and the real-time values ​​of the active and reactive components, and uses the regulator to generate rotor voltage commands.

8. The method according to claim 7, characterized in that, Space voltage vector pulse width modulation generates the duty cycle or operating time of each power switching device in the rotor-side converter based on the rotor voltage command, so as to control the rotor-side converter to adjust the rotor angular velocity.

9. The method according to claim 1, characterized in that, Also includes: After the equivalent virtual inertia support control provided by the synchronous condenser system ends, the rotor angular velocity of the synchronous condenser system adaptively recovers.

10. The method according to claim 9, characterized in that, The adaptive recovery of the rotor speed of the synchronous condenser system includes: When the power grid is in the first frequency regulation stage after the equivalent virtual inertia support control ends, there is a steady-state frequency deviation between the real-time frequency of the power grid and the rated frequency of the power grid. The rotor angular velocity of the control synchronous condenser system is stabilized at the angular velocity corresponding to the real-time power grid frequency. When the power grid is in the secondary frequency regulation stage after the equivalent virtual inertia support control ends, the real-time frequency of the power grid gradually returns to the rated frequency of the power grid. The synchronous condenser system responds to the change in the power grid frequency, and the rotor angular velocity recovers to the angular velocity corresponding to the rated frequency of the power grid.

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