A method for improving the inertia of a phase modifier by a flexible excitation configuration of energy storage

Abstract

This invention discloses a method for configuring an energy storage-type flexible excitation system to enhance the inertia of a synchronous condenser (SC). The method includes: designing an energy storage-type flexible excitation system for the SC; designing an inertia enhancement control mode for the flexible excitation system, wherein when the deviation between the grid frequency and the reference frequency exceeds a threshold, the inertia support function is activated, an active current regulation command is applied, and active power is exchanged with the grid through the voltage source converter (VSC) to achieve inertia support; based on the normal and disturbed operating modes of the synchronous condenser; establishing a grid-connected system with the energy storage-type flexible excitation system on a simulation platform, simulating the frequency disturbance trajectory of the system under power imbalance disturbances, thereby verifying the effect of energy storage-type flexible excitation on the inertia enhancement of the SC. The energy storage-type flexible excitation system proposed in this invention not only possesses the reactive power and voltage support function of a conventional excitation system, but also improves the frequency regulation performance of the SC, while rapidly exchanging power with the grid to ensure that the forced excitation effect is not affected by the generator terminal voltage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power system safety and stability analysis, and particularly relates to a configuration method of energy storage type flexible excitation for improving the inertia of a phase modifier. BACKGROUND

[0002] In recent years, with the continuous grid connection of low-inertia power sources such as wind power and photovoltaic power, the generation proportion of traditional power sources is continuously decreasing, the frequency fluctuation of the system under the same power shortage is more significant, and the frequency stability level of the system is declining. At the same time, the dense feeding of ultra-high voltage direct current and the transmission of large power intensify the replacement effect of conventional power sources, and the inertia level of the direct current receiving end system is greatly reduced. The changing trend of power source structure and power grid structure is significantly changing the inertia level and frequency regulation capacity of the power system, and frequency stability accidents occur from time to time, which sounds the alarm for the safe and stable operation of large power grids.

[0003] In recent years, new type of distributed phase modifier plays an important supporting role in improving the short circuit ratio and transient voltage support capacity of new energy station due to its strong transient reactive power support capacity. However, due to the lack of prime mover and governor and the small rotating inertia of the rotor, the inertia support and primary frequency regulation support capacity of the system is weak.

[0004] In order to improve the inertia support capacity of the phase modifier, the current common schemes include "conventional synchronous phase modifier + flywheel", "double-fed phase modifier + coaxial flywheel", double-shaft excitation synchronous phase modifier and superconducting synchronous phase modifier. Among them, the "conventional synchronous phase modifier + flywheel" scheme does not need to modify the original phase modifier, but needs to add flywheel mechanical equipment, which leads to the oversize of the phase modifier body, and increases the investment and loss. Other types of phase modifier need to use new type of phase modifier equipment, which has great difficulty in technical modification. In the prior art, the phase modifier needs to be modified into a double-fed unit, which has great difficulty in technical modification.

[0005] The phase modifier currently basically adopts a static frequency converter (SFC) starting mode, which accounts for a high cost proportion of secondary equipment. However, since it is only used for starting, the equipment is in an idle state after being connected to the grid, and the utilization rate of the equipment is very low. In order to improve the economic cost of the phase modifier, the prior art configures a flexible excitation system for the phase modifier to realize the starting / excitation integration of the phase modifier, and solves the high cost caused by the configuration of the static frequency converter (SFC) starting equipment. However, only the flexible excitation system is applied to reduce the starting cost of the phase modifier, and the full potential of the flexible excitation system cannot be developed, and the dynamic support of the flexible excitation system to the phase modifier cannot be developed. SUMMARY

[0006] Objective of the Invention: Addressing the problems existing in the prior art, the objective of this invention is to provide a method for configuring a flexible excitation system with energy storage to enhance the inertia of the synchronous condenser. In designing the flexible excitation system with energy storage, the energy storage device is connected in parallel with a supercapacitor, and excitation is provided to the synchronous condenser through a bidirectional DC / DC converter. The flexible excitation system not only rapidly provides reactive power to the generator terminal, improving the reactive power support capability and response speed of the SC (Synchronous Condenser), but also allows the energy storage device to exchange active power with the grid through the VSC (Voltage Controlled Synchronous Condenser), enhancing the inertia support capability of the SC.

[0007] Technical solution: The present invention provides a method for configuring a flexible excitation system for improving the inertia of a synchronous condenser, comprising the following steps:

[0008] Step 1: Design an energy storage type flexible excitation system for the synchronous condenser SC;

[0009] Step 2: Based on the energy storage type flexible excitation system, design a control mode for the flexible excitation system to improve the inertia of the synchronous condenser;

[0010] Step 3: Based on the working modes of the flexible excitation synchronous condenser with energy storage under normal and disturbed conditions, determine the working scheme of the flexible excitation.

[0011] Step 4: Establish a grid-connected system of a synchronous condenser with energy storage flexible excitation based on the simulation platform, simulate the frequency disturbance trajectory of the system under power imbalance disturbance, and verify the effect of energy storage flexible excitation on the inertia improvement of the synchronous condenser.

[0012] Further, step 1 specifically involves: the energy storage flexible excitation system includes an excitation transformer, a power converter, an energy storage device, and a controller; the energy storage device is connected in parallel with the supercapacitor and provides excitation to the synchronous condenser SC through the power converter; at the same time, the energy storage device exchanges active power with the grid through the voltage source converter VSC to enhance the inertia support capability of the synchronous condenser SC.

[0013] Furthermore, step 2 specifically includes the following steps:

[0014] Step 2.1: The hybrid energy storage device, consisting of batteries and supercapacitors, acts as a static power generation unit. It utilizes its stored energy through active power control to provide inertial support for the system. Let the rated capacity of the energy storage device be E. sn The state of charge is S SOC The energy E stored in the energy storage device s for:

[0015] (1);

[0016] If all the energy from the hybrid energy storage is used for the inertia support of the condenser SC, then:

[0017] (2);

[0018] Among them, J v ω is the virtual rotational inertia of the hybrid energy storage, and ω is the rotor angular velocity of the synchronous condenser.

[0019] According to equation (2), we can obtain:

[0020] (3);

[0021] Step 2.2: Let the actual moment of inertia of the camera SC be J. sc Its kinetic energy E at rated speed k Represented as:

[0022] (4);

[0023] Where ω0 is the rated rotational speed of the camera, S scn To adjust the camera's rated capacity, T sc To adjust the camera's inertia;

[0024] The virtual inertial time constant T of hybrid energy storage v Represented as:

[0025] (5);

[0026] As shown in equation (5), if the energy storage capacity is entirely used to support the rated inertia of the synchronous condenser, the maximum virtual inertia it can provide is T. v ;

[0027] Step 2.3: Measure the grid frequency. When the deviation between the grid frequency and the reference frequency exceeds the threshold, the inertia support control function of the flexible excitation system is activated, and the active current regulation command is applied. The active power is exchanged with the grid through the voltage source converter (VSC) to achieve inertia support, thereby regulating the grid frequency.

[0028] The inertia support control method of the energy storage flexible excitation system is shown in equation (6), that is:

[0029] (6);

[0030] In the formula, P f Δf represents the inertial support power of the energy storage flexible excitation system; Δf is the system frequency deviation, and Δf = f s -f N f s and f N These are the system frequency and the system rated frequency, respectively, k d k is the virtual inertia time constant. d ≤T v k p The droop control ratio is t, where t is time.

[0031] Combining equation (6) with the rotor motion equation of the synchronous condenser, we obtain the load frequency transfer function of the synchronous condenser with energy storage flexible excitation, which is as follows:

[0032] (7);

[0033] In the formula, ΔP d Let be the system power imbalance, s be the Laplace transform factor, D be the damping coefficient, and T be the damping factor. sc To adjust the camera's inertia; due to k d and k p Since the frequency regulation effect of SC is related to the state of charge (SOC) of the energy storage, it is related to the SOC of the energy storage.

[0034] Furthermore, step 3 specifically includes the following operating modes: normal operation, small disturbance, large disturbance, and post-steady state;

[0035] Normal operation: The energy storage type flexible excitation system only needs to provide a stable excitation voltage and does not need to exchange active and reactive power with the grid; at this time, the energy storage element is locked and the excitation system energy is provided from the grid side;

[0036] Small disturbance: When a small disturbance occurs in the power system, the energy storage unit injects active power P into the synchronous condenser SC according to the upper-level control command. f ;

[0037] Large disturbance: When a serious system fault causes a significant drop in terminal voltage, the flexible excitation quickly raises the DC-side capacitor voltage according to the command value to provide a continuous and stable strong excitation;

[0038] Post-steady state: After the disturbance ends, the system enters the post-steady state stage. The energy storage system absorbs power from the grid to replenish the energy consumed during the fault, and the system enters normal operation.

[0039] Furthermore, step 4 specifically includes the following steps:

[0040] Step 4.1: Based on the MATLAB platform, construct a grid-connected simulation system for a synchronous condenser with energy storage-type flexible excitation;

[0041] Step 4.2: Set up power imbalance disturbances to obtain the frequency disturbance trajectories of all synchronous generators in the system, as well as the frequency disturbance trajectories and active power disturbance trajectories of the flexible excitation condenser with energy storage.

[0042] Step 4.3: Based on the frequency disturbance trajectories of all synchronous generators and the flexible excitation condenser containing energy storage, obtain the frequency f of the system's center of inertia. COI Disturbed trajectory;

[0043] (8);

[0044] Where G represents the set of synchronous generators; T i and f i Let T represent the inertia and frequency of the i-th synchronous generator, respectively; sc and f sc T represents the inertia and frequency of the camera, respectively. sc To adjust the camera's inertia, k d The virtual inertia time constant;

[0045] Step 4.4, according to f COI The initial rate of change is used to calculate the total inertia of the system. Subtracting the inertia of all synchronous generators and the inertia of the synchronous condenser itself, the difference is the virtual inertia of the synchronous condenser. The values ​​of the virtual inertia under different energy storage capacities are analyzed to verify the inertia support effect of energy storage-type flexible excitation.

[0046] Furthermore, the power converter is a bidirectional power converter, including AC / DC and DC / DC converters.

[0047] This invention also discloses an energy storage type flexible excitation configuration system for improving the inertia of a synchronous condenser, comprising:

[0048] Calculation unit: used to calculate the maximum virtual inertia that can be provided based on the rated capacity of the energy storage device;

[0049] Judgment Unit: Determines whether the deviation between the power grid frequency and the reference frequency exceeds a threshold and obtains the judgment result;

[0050] Control unit: Based on the result of the judgment unit, it issues an active current regulation command, exchanges active power with the grid through the voltage source converter (VSC) to achieve inertia support, thereby regulating the grid frequency;

[0051] Simulation Unit: Based on the MATLAB platform, a grid-connected simulation system with a synchronous condenser containing energy storage flexible excitation is built. The frequency response of the system's center of inertia under power imbalance disturbance is analyzed, thereby verifying the inertial support effect of the energy storage flexible excitation on the synchronous condenser.

[0052] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method of the present invention.

[0053] The present invention also discloses a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implements the steps of the method of the present invention.

[0054] The present invention also discloses a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the method of the present invention.

[0055] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention proposes a method for configuring energy storage-based flexible excitation to enhance the inertia of a synchronous condenser. By calculating the deviation between the grid frequency and the reference frequency, inertia support and primary frequency regulation are activated when the deviation exceeds a threshold. The energy storage-based flexible excitation system not only possesses the reactive power and voltage support function of conventional excitation systems, improving the frequency regulation performance of the synchronous condenser and reducing the risk of frequency instability in systems with a high proportion of renewable energy, but also, because the energy storage device in the flexible excitation system can quickly exchange power with the grid, ensuring that the forced excitation effect is not affected by the generator terminal voltage, the synchronous condenser based on the energy storage-based flexible excitation system can significantly improve the transient stability of the system and increase the utilization rate of renewable energy. Attached Figure Description

[0056] Figure 1 This is a flowchart of the method of the present invention;

[0057] Figure 2 A block diagram of an energy storage-type flexible excitation system;

[0058] Figure 3 This is a block diagram of the load frequency control for a synchronous condenser with energy storage-type flexible excitation.

[0059] Figure 4 This is a system diagram of a 4-machine, 2-area system including a synchronous condenser with a flexible excitation system for energy storage;

[0060] Figure 5 The system's inertia center frequency is disturbed trajectory diagram;

[0061] Figure 6 for Figure 5 Enlarged view of the yellow rectangle in the middle;

[0062] Figure 7 This is the active power output diagram of a flexible system with energy storage. Detailed Implementation

[0063] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0064] based on Figure 1 The process shown in the figure illustrates a method for configuring a flexible excitation system for improving the inertia of a synchronous condenser, proposed in this invention, comprising the following steps:

[0065] Step 1: An energy storage type flexible excitation system was designed for the synchronous condenser SC;

[0066] See attached: Energy storage type flexible excitation system Figure 2As shown, it consists of an excitation transformer, power converters (AC / DC, DC / DC), energy storage devices, and corresponding controllers. The energy storage devices are connected in parallel with the capacitors and provide excitation to the synchronous condenser through a bidirectional DC / DC converter. The flexible excitation system can quickly provide reactive power to the generator terminals, improving the reactive power support capability and response speed of the SC; at the same time, the energy storage devices exchange active power with the grid through the voltage source converter (VSC), improving the inertia support capability of the SC.

[0067] Step 2: Design a flexible excitation system control mode to enhance the inertia of the synchronous condenser;

[0068] A hybrid energy storage device consisting of batteries and supercapacitors is a static power generation unit. Through active power control, it can quickly utilize its stored energy to provide inertial support for the system. Let the rated capacity of the energy storage device be E. sn The state of charge is S SOC The energy stored in the energy storage device is:

[0069] (1)

[0070] If all the energy from the hybrid energy storage is used for the inertia support of the SC, then:

[0071] (2)

[0072] Among them, J v Let ω be the virtual rotational inertia of the hybrid energy storage, and ω be the rotor angular velocity of the synchronous condenser.

[0073] According to equation (2), we can obtain:

[0074] (3)

[0075] Let the actual moment of inertia of SC be J. sc Its kinetic energy E at rated speed k Represented as:

[0076] (4)

[0077] Where ω0 is the rated rotational speed of the camera, S scn To adjust the camera's rated capacity.

[0078] The virtual inertial time constant T of hybrid energy storage v It can be represented as:

[0079] (5)

[0080] As can be seen from equation (5), if the energy storage capacity is entirely used to support the rated inertia of the synchronous condenser, the maximum virtual inertia it can provide is T.v .

[0081] When the deviation between the grid frequency and the reference frequency exceeds a threshold, the inertia support control function of the flexible excitation system is activated, and an active current regulation command is applied. The active power is exchanged with the grid through the voltage source converter (VSC) to achieve inertia support, thereby regulating the grid frequency.

[0082] The inertia support control method of the energy storage flexible excitation system is shown in equation (6), that is:

[0083] (6)

[0084] In the formula, P f The inertia support power of the energy storage flexible excitation system; Δf is the system frequency deviation, i.e., Δf = f s -f N f s and f N These are the system frequency and the system rated frequency, respectively, k d The virtual inertia time constant (k) d ≤T v ), k p This is the droop control ratio coefficient.

[0085] Combining equation (6) with the rotor motion equation of the synchronous condenser, we obtain the load frequency transfer function of the synchronous condenser with energy storage-type flexible excitation, see [reference needed]. Figure 3 Its transfer function is:

[0086] (7)

[0087] In the formula, ΔP d Let D be the system power imbalance, and D be the damping coefficient. It should be noted that, due to k... d and k p Since the frequency regulation effect of SC is related to the state of charge (SOC) of the energy storage, it is related to the SOC of the energy storage.

[0088] Step 3: Based on the working modes of the flexible excitation synchronous condenser with energy storage under normal and disturbed conditions, determine the working scheme of the flexible excitation.

[0089] Normal operation: The energy storage-type flexible excitation system only needs to provide a stable excitation voltage and does not need to exchange active and reactive power with the grid. At this time, the energy storage element is locked, and the excitation system's energy is provided from the grid side.

[0090] Small disturbance: When a small disturbance occurs in the power system, the energy storage unit injects active power P into the SC according to the upper-level control command. c and reactive power Q c .

[0091] Large disturbance: When a serious system fault causes a significant drop in the terminal voltage, the flexible excitation quickly raises the DC-side capacitor voltage according to the command value to provide a continuous and stable strong excitation.

[0092] Post-steady state: After the system is disturbed and enters the post-steady state, the energy storage system absorbs power from the grid to make up for the power consumption during the fault, and the system is in normal operation mode.

[0093] Step 4: Establish a grid-connected system for a synchronous condenser with energy storage flexible excitation based on the MATLAB platform, simulate the frequency disturbance trajectory of the system under power imbalance disturbance, and verify the effect of energy storage flexible excitation on the inertia improvement of the synchronous condenser.

[0094] Step 4.1: Establish a grid-connected system with a synchronous condenser containing energy storage-type flexible excitation based on the MATLAB platform. This grid-connected system is a standard 4-machine 2-area system. The synchronous condenser is installed at the load L7, replacing the original capacitor compensation device at L7. See [link to documentation]. Figure 4 .

[0095] Step 4.2, Disturbance settings t =1s L 9. Load suddenly increases by 100MW, with different virtual inertia coefficients k d See the dynamics of the lower system inertia center frequency. Figure 5 , Figure 5 See the enlarged view of the yellow rectangle in the image. Figure 6 The active power output trajectory of the camera is disturbed. Figure 7 As shown.

[0096] Step 4.3: Based on the frequency disturbance trajectories of each synchronous generator and the flexible excitation condenser containing energy storage, obtain the frequency f of the system's inertial center. COI Disturbed trajectory;

[0097] (8)

[0098] Where G represents the set of synchronous generators; T i and f i Let T represent the inertia and frequency of the i-th synchronous generator, respectively; sc and f sc These represent the inertia and frequency of the camera, respectively; k p This represents the virtual inertia of the camera.

[0099] from Figure 7 It can be seen that k d When k = 0, the active power output of the synchronous condenser is zero when a power imbalance disturbance occurs in the system, meaning it does not respond to changes in the system's power; d The larger the value of k, the greater the active power output and the greater the support for power imbalance disturbances in the system; simultaneously, kd The larger the value, the faster the power rises during the initial stage of a fault, indicating a stronger inertia support capability.

[0100] Step 4.4, according to f COI The initial stage rate of change is calculated by subtracting the inertia of all synchronous generators and the inertia of the synchronous condenser from the total inertia of the system. The difference is the virtual inertia of the synchronous condenser.

[0101] Total theoretical inertia T of a 4-machine 2-region system r (converted to S) B =900MVA) is:

[0102] T r = [ ∑ i = 1 4 T i S B i + ( H sc + k d / 2 ) S sc ] / S B (9)

[0103] In the formula, T r The total theoretical inertia of the 4-machine 2-region system, T i Let S be the inertia of the i-th synchronous generator. Bi H represents the rated capacity of the i-th synchronous generator. sc and S sc These are the inertia and rated capacity of the camera, respectively; S B This represents the system's baseline capacity.

[0104] According to equation (9), when k d When the values ​​are 0 and 6, the virtual inertia are 0 and 1s, respectively, and the theoretical equivalent inertia of the system are 26.02s and 27.02s, respectively.

[0105] Further based on Figure 6 The change in the system's inertial center frequency at the initial instant of disturbance is shown. Estimate the equivalent inertia of the system.

[0106] (1) k d When =0, first, based on the load mutation of L9, the rate of change of the initial frequency of the system's center of inertia ( Figure 5 The Hz / s of the system (within the yellow rectangle) is 0.11222 Hz. The calculated unbalanced power of the system is:

[0107] (10)

[0108] In the formula, ΔP represents the power imbalance of the system. G1 ~ΔP G4 These represent the power imbalance of synchronous generators G1 to G4, ΔP. sc To adjust the power imbalance of the camera.

[0109] This leads to the estimated equivalent inertia T of the system. e for:

[0110] (11)

[0111] In the formula, T e Δf is the estimated equivalent inertia of the system, and Δf is the frequency change within the time period Δt.

[0112] Inertia estimation error for:

[0113] (12)

[0114] In the formula, This is the error in inertia estimation.

[0115] (2) k d When =6, first, based on the load mutation of L9, the rate of change of the initial frequency of the system's center of inertia ( Figure 5 The yellow rectangle indicates a frequency of 0.11360 Hz / s, and the unbalanced power of the system is:

[0116] (13)

[0117] The equivalent inertia coefficient of the system under this condition is calculated as follows:

[0118] (14)

[0119] The inertia estimation error is:

[0120] (15)

[0121] Comparing the estimated and actual values ​​of inertia, we can see that: 1) the estimated value is close to the actual value, which shows the feasibility of the inertia estimation method; 2) according to the estimation results, the larger the virtual inertia coefficient of SC, the larger the equivalent inertia of the system, and the stronger the inertia support capability of the system.

[0122] This invention also discloses a synchronous condenser inertia enhancement system based on energy storage-type flexible excitation, comprising:

[0123] Calculation unit: used to calculate the maximum virtual inertia that can be provided based on the rated capacity of the energy storage device;

[0124] Judgment Unit: Determines whether the deviation between the power grid frequency and the reference frequency exceeds a threshold and obtains the judgment result;

[0125] Control unit: Based on the result of the judgment unit, it issues an active current regulation command, exchanges active power with the grid through the voltage source converter (VSC) to achieve inertia support, thereby regulating the grid frequency;

[0126] Simulation Unit: Based on the MATLAB platform, a grid-connected simulation system with a synchronous condenser containing energy storage flexible excitation is built. The frequency response of the system's center of inertia under power imbalance disturbance is analyzed, thereby verifying the inertial support effect of the energy storage flexible excitation on the synchronous condenser.

[0127] The specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, any technical solution that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims. Finally, it should be noted that the above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for the energy storage type flexible excitation configuration of the phase modifier inertia boost, characterized by, Comprising the following steps: Step 1, design a flexible excitation system with energy storage for phase modifier SC; Step 2, based on the flexible excitation system with energy storage, design a flexible excitation system control strategy to improve the inertia of the phase modifier; Step 2 specifically includes the following steps: Step 2.

1. The hybrid energy storage device consisting of batteries and supercapacitors as a static power generation unit, through active control to call their own stored energy, to provide inertia support for the system; set the rated capacity of the energy storage device E sn , the state of charge S SOC , then the energy stored by the energy storage device E s is: (1)； If the energy of the hybrid energy storage is used entirely for inertia support of the phase modifier SC, then: (2)； where J v is the virtual moment of inertia of the hybrid energy storage, and ω is the rotor angular velocity of the phase modifier. According to formula 2, we can get: (3)； Step 2.2, set the actual moment of inertia of the camera SC to J sc its kinetic energy E at the rated rotational speed k is expressed as: (4)； where ω0is the rated rotational speed of the phase modifier, S scn is the rated capacity of the phase modifier, T sc is the inertia of the phase modifier; The virtual inertia time constant T of the hybrid energy storage is then v is represented as: (5)； As shown in equation 5, if the energy storage capacity is used entirely to support the inertia of the phase modifier, the maximum virtual inertia that can be provided is T v ; Step 2.3, measure the grid frequency, when the deviation of the grid frequency and the reference frequency exceeds the threshold value, the inertia support control function of the flexible excitation system acts, the active current regulation instruction is put into, the active power is exchanged between the voltage source converter VSC and the grid to realize the inertia support, so as to regulate the grid frequency; The inertia support control mode of the flexible excitation system with energy storage is shown in formula 6, that is: (6)； where P f is the inertia support power of the energy storage type flexible excitation system; Δf is the system frequency deviation, and Δf=f s -f N , f s and f N are the system frequency and the system rated frequency respectively, k d is the virtual inertia time constant, k d ≤T v , k p is the droop control proportional coefficient, and t is the time; Combining formula 6 with the rotor motion equation of the phase modifier, the load frequency transfer function of the phase modifier containing the flexible excitation with energy storage is obtained, which is specifically: (7)； In the formula, ΔP d is the system power imbalance, s is the Laplace transform factor, D is the damping coefficient, T sc is the inertia of the phase modifier; since k d and k p are related to the state of charge SOC of the energy storage, the frequency modulation effect of the SC is related to the state of charge of the energy storage; Step 3, based on the working mode of the phase modifier containing the flexible excitation with energy storage under normal and disturbed conditions, determine the working scheme of the flexible excitation; Step 4, based on the simulation platform, establish a grid-connected system containing a phase modifier with flexible excitation with energy storage, simulate the frequency disturbance trajectory of the system under power imbalance disturbance, and verify the inertia improvement effect of the flexible excitation with energy storage on the phase modifier accordingly.

2. The method of claim 1, wherein the method is a method of flexible excitation configuration of an energy storage type for an inductance boost of a phase-modulator, characterized in that, Step 1 specifically: the flexible excitation system with energy storage includes an excitation transformer, a power converter, a super capacitor, a controller and an energy storage device; the energy storage device is connected in parallel with the super capacitor, and the power converter provides excitation to the phase modifier SC, while the energy storage device exchanges active power with the grid through the voltage source converter VSC.

3. The method of claim 1, wherein the method is a method of flexible excitation configuration of an energy storage type for an inductance boost of a phase-modulator, characterized in that, Step 3 specifically: the working mode includes normal operation, small disturbance, large disturbance and post steady state; Normal operation: the flexible excitation system with energy storage only needs to provide stable excitation voltage, and does not need to exchange active power and reactive power with the grid; at this time, the energy storage element is locked, and the energy of the excitation system is provided from the grid side; Small disturbance: when the power system is disturbed, the energy storage unit injects active power P to the phase modifier SC according to the upper control instruction f ; Large disturbance: when the system occurs serious fault leading to large drop of terminal voltage, the flexible excitation rapidly lifts the DC side capacitor voltage according to the instruction value, and provides continuous and stable strong excitation; Post steady state: after the system is disturbed, it enters the post steady state stage, and the energy storage system absorbs power from the grid to supplement the power consumption during the fault, and the system enters the normal operation state.

4. The method of claim 1, wherein the method is a method of flexible excitation configuration of an energy storage type for an inductance boost of a phase modifier, characterized by, Step 4 specifically includes the following steps: Step 4.1, based on the MATLAB platform, construct a grid-connected simulation system containing a phase modifier with flexible excitation with energy storage; Step 4.2, set power imbalance disturbance, obtain the frequency disturbance trajectory of all synchronous generators in the system, as well as the frequency disturbance trajectory and active power disturbance trajectory of the phase modifier containing the flexible excitation with energy storage; Step 4.

3. Obtain the frequency f of the center of inertia of the system from the disturbed trajectories of all synchronous generators and frequency- disturbed trajectories of the flexible excitation phase modifier with energy storage COI Disturbed trajectories; (8)； where G represents a set of synchronous generators; T i and f i represent the inertia and frequency of the ithsynchronous generator, respectively; T sc and f sc represent the inertia and frequency of the phase modifier, respectively, T sc is the inertia of the phase modifier, k d is the virtual inertia time constant; Step 4.4, according to f COI The total inertia of the starting change rate calculation system is subtracted from the inertia of all synchronous generators and the inertia of the phase modifier itself, and the difference is the virtual inertia of the phase modifier. The values of the virtual inertia under different energy storage capacities are analyzed to verify the inertia support effect of the energy storage type flexible excitation.

5. The method of claim 2, wherein the method is a method of flexible excitation configuration of an energy storage type of phase modifier inertia boost, characterized by, The power converter is a bidirectional power converter, including AC / DC and DC / DC.

6. A flexible excitation configuration system of the energy storage type for the purpose of inertia boosting of a phase modifier, for implementing the method as claimed in claim 1, characterized in that, Comprising: A calculation unit for calculating the maximum virtual inertia according to the rated capacity of the energy storage device; A judgment unit for judging whether the deviation of the grid frequency and the reference frequency exceeds the threshold value, and obtaining a judgment result; A control unit for putting in the active current regulation instruction according to the result of the judgment unit, exchanging active power between the voltage source converter VSC and the grid to realize inertia support, so as to regulate the grid frequency; Simulation unit: Based on MATLAB platform, the simulation system of the synchronous condenser with energy storage flexible excitation is established, the frequency response of the inertia center of the system under the power imbalance disturbance is analyzed, and the inertia support effect of the energy storage flexible excitation on the synchronous condenser is verified.

7. A computer apparatus comprising a memory, a processor, and a computer program stored on the memory, wherein the computer program, when executed by the processor, causes the processor to perform the method of any one of claims 1 to 6. The processor executes the computer program to implement the steps of the method of claim 1.

8. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to implement the steps of the method of claim 1.

9. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to implement the steps of the method of claim 1. The computer program / instruction is executed by the processor to implement the steps of the method of claim 1.

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