Transient synchronous supporting method and device for energy storage type double-fed phase modifier and medium

Abstract

The invention provides an energy storage type double-fed phase modifier transient synchronous supporting method and device and a medium, and relates to the technical field of electric power. The method comprises the following steps: when voltage drop and frequency disturbance occur in a power system, determining an adaptive reactive current proportionality coefficient according to a voltage deviation normalized value, a frequency deviation normalized value and a frequency change rate normalized value of a machine end of the energy storage type doubly-fed phase modifier by adopting a control strategy of reactive power priority and active power amplitude limiting by the energy storage type doubly-fed phase modifier; determining a target reactive current according to the adaptive reactive current proportionality coefficient so as to carry out reactive control on the energy storage type double-fed phase modifier; and in combination with the amplitude limiting effect of the virtual inertia control and the adaptive reactive current proportionality coefficient on the active current, obtaining a target active current so as to carry out active control on the energy storage type double-fed phase modifier. According to the invention, when voltage drop and frequency disturbance occur in a power system, the active and reactive output proportion can be dynamically adjusted, and the overall stability of voltage and frequency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power, and in particular to a transient synchronous support method, device and medium for an energy storage type doubly-fed phase modifier. BACKGROUND

[0002] Due to the increasingly prominent double-high (high proportion of renewable energy grid connection and high proportion of power electronic equipment application) characteristics of the power system, the system short-circuit ratio and inertia are on the decline, and the risk of voltage and frequency instability is increasing. With the improvement of the voltage support capability of the synchronous phase modifier, the system voltage problem is obviously improved, but the conventional synchronous phase modifier has less effective energy storage, cannot actively adjust the rotor speed, and has insufficient transient active power support capability, which cannot meet the frequency support demand of the power system. Compared with the synchronous phase modifier with the above problems, the energy storage type doubly-fed phase modifier using alternating current excitation can not only provide transient reactive current to suppress system voltage changes, but also can adjust the rotor speed in a wide range to provide inertia support to the power grid.

[0003] In terms of voltage support, the energy storage type doubly-fed phase modifier can achieve reactive power regulation through different control modes: one adopts a constant power control mode to adjust reactive power output according to the upper command; the other adopts a constant voltage control mode to quickly respond to system voltage changes with the machine terminal voltage as the control target. In terms of frequency support, the early method realizes active power regulation through the switching of speed control mode and power control mode, and the subsequent frequency differential element is added to the power control mode, so that it presents an inertia response external characteristic; to avoid switching between control modes, there is also a method of directly integrating the frequency differential element into the speed outer loop control, so that the energy storage type doubly-fed phase modifier has both steady-state speed regulation and transient inertia support capability.

[0004] However, when the power system experiences voltage drop and frequency disturbance, the above methods cannot dynamically adjust the output proportion of active and reactive power, resulting in poor overall stability of voltage and frequency. SUMMARY

[0005] The embodiments of the present application provide a transient synchronous support method, device and medium for an energy storage type doubly-fed phase modifier, to dynamically adjust the output proportion of active and reactive power when the power system experiences voltage drop and frequency disturbance, and improve the overall stability of voltage and frequency.

[0006] In a first aspect, the embodiments of the present application provide a transient synchronous support method for an energy storage type doubly-fed phase modifier, comprising: When the power system experiences voltage drop and frequency disturbance, the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value of the machine terminal of the energy storage type doubly-fed phase modifier are obtained; An adaptive reactive current proportion coefficient is determined according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value. determining a dynamic reactive current increment according to the adaptive reactive current proportion coefficient and the voltage drop depth, determining a target reactive current according to the dynamic reactive current increment and a reactive current output by the energy storage type doubly-fed phase modifier before voltage drop, so as to perform reactive control on the energy storage type doubly-fed phase modifier; combining the virtual inertia control and the amplitude limiting effect of the adaptive reactive current proportion coefficient on the active current, so as to obtain a target active current to perform active control on the energy storage type doubly-fed phase modifier.

[0007] In a possible implementation, the adaptive reactive current proportion coefficient is determined according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value, comprising: determining an adjusted value of the adaptive reactive current proportion coefficient ; if the adjusted value is less than or equal to a minimum limit value of the adaptive reactive current proportion coefficient, the minimum limit value is determined as the adaptive reactive current proportion coefficient; if the adjusted value is greater than or equal to a maximum limit value of the adaptive reactive current proportion coefficient, the maximum limit value is determined as the adaptive reactive current proportion coefficient; if the adjusted value is between the minimum limit value and the maximum limit value, the adjusted value is determined as the adaptive reactive current proportion coefficient; wherein, K x is the adjusted value; K 0 is a basic coefficient; K u is a voltage deviation compensation coefficient; K f1 is a frequency deviation compensation coefficient; K f2 is a frequency change rate compensation coefficient; K 0, K u , K f1 , K f2 are all greater than 0; x 1 is a voltage deviation normalized value; x 2 is a frequency deviation normalized value; x 3 is a frequency change rate normalized value.

[0008] In a possible implementation, before the adaptive reactive current proportion coefficient is determined according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value, the method further comprises: Obtain the minimum and maximum limits of the adaptive reactive current proportional coefficient of the energy storage type doubly fed camera; The basic coefficient, the voltage deviation compensation coefficient, the frequency deviation compensation coefficient, and the frequency change rate compensation coefficient are determined based on the minimum limit and the maximum limit.

[0009] In one possible implementation, obtaining the minimum and maximum limits of the adaptive reactive current proportional coefficient of the energy storage-type doubly-fed camera includes: Obtain the stator overload factor of the energy storage type doubly fed camera. m c and rotor overload multiple n c Preset stator overload multiple of wind turbine m w and rotor overload multiple n w And the minimum reactive current proportionality coefficient given by the fault ride-through standard for wind turbines. K w,min With the maximum value K w,max ; according to Determine the minimum limit of the adaptive reactive current proportional coefficient of the energy storage type doubly fed camera; according to Determine the maximum limit value of the adaptive reactive current proportional coefficient of the energy storage type doubly fed camera; in, K c,min The minimum limit, K c,max This is the maximum limit value.

[0010] In one possible implementation, determining the basic coefficient, the voltage deviation compensation coefficient, the frequency deviation compensation coefficient, and the frequency change rate compensation coefficient based on the minimum limit and the maximum limit includes: according to Determine the basic coefficients; according to Determine the range of values ​​for the voltage deviation compensation coefficient, and then determine the voltage deviation compensation coefficient based on the range of values ​​for the voltage deviation compensation coefficient. according to{ Determine the value range of the frequency deviation compensation coefficient and the frequency change rate compensation coefficient. Based on the value range of the frequency deviation compensation coefficient and the frequency change rate compensation coefficient, determine the frequency deviation compensation coefficient and the frequency change rate compensation coefficient. in, K 0 is the basic coefficient; K uThis is the voltage deviation compensation coefficient; K f1 This is the frequency deviation compensation coefficient; K f2 This is the frequency change rate compensation coefficient; K 0、 K u , K f1 , K f2 All are greater than 0.

[0011] In one possible implementation, the target active current is obtained by combining virtual inertia control with the limiting effect of the adaptive reactive current proportional coefficient on the active current, including: according to Obtain the target active current; in, i rd,ref The target active current; The active current is calculated based on the active power reference value given by virtual inertia control. P s,ref The active power reference value given to the energy storage type doubly fed camera for virtual inertia control; U s The terminal voltage of the energy storage type doubly fed camera; L s For stator inductance; L m For mutual inductance between the stator and rotor; I r,max This represents the maximum current in the rotor winding. U sf This refers to the per-unit value of the terminal voltage of the energy storage type dual-feed camera. I N The rated current of the energy storage type dual-feed camera; ω s This is the synchronization angular frequency; I q0 The reactive current output by the energy storage type doubly fed synchronous condenser before the voltage drop; K c This is the adaptive reactive current proportional coefficient.

[0012] In one possible implementation, obtaining the normalized values ​​of voltage deviation, frequency deviation, and frequency change rate at the terminal of the energy storage type doubly fed camera includes: Obtain the terminal voltage and grid frequency of the energy storage type doubly fed synchronous condenser; The voltage deviation normalization value is determined based on the terminal voltage of the energy storage type doubly fed synchronous condenser, and the frequency deviation normalization value and the frequency change rate normalization value are determined based on the grid frequency.

[0013] In one possible implementation, the method further includes: When the frequency is stable, the energy storage type doubly fed camera is subjected to constant speed active power control; When no voltage drop occurs in the power system, but the frequency disturbance crosses the dead zone, the active power control of the energy storage type doubly fed synchronous condenser is performed based on the active current given by the virtual inertia control.

[0014] In a second aspect, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect or any possible implementation thereof.

[0015] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect or any possible implementation thereof.

[0016] Fourthly, embodiments of the present invention provide a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect or any possible implementation thereof.

[0017] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The voltage and frequency of a power system change dynamically during faults, and the limitations of a fixed reactive current proportional coefficient make it difficult for energy storage-type doubly-fed induction generators (DFIGs) to adapt to different fault levels. In this embodiment of the invention, when a voltage dip and frequency disturbance occur in the power system, an adaptive reactive current proportional coefficient is constructed using the normalized values ​​of voltage deviation, frequency deviation, and frequency change rate at the DFIG terminal. In the reactive power control stage, the dynamic reactive current increment is determined based on the adaptive reactive current proportional coefficient and the voltage dip depth. The target reactive current is then determined based on the dynamic reactive current increment and the reactive current output by the DFIG before the voltage dip to perform reactive power control on the DFIG. In the active power control stage, the target active current is obtained by combining virtual inertia control with the limiting effect of the adaptive reactive current proportional coefficient on the active current to perform active power control on the DFIG. This embodiment achieves synchronous support for voltage and frequency, and the adaptive adjustment coefficient of reactive current is designed as a function of voltage deviation, frequency deviation, and frequency change rate. It can automatically adjust according to the real-time voltage and frequency status, enhancing the coordination capability of active and reactive power output of the energy storage type doubly fed camera. Attached Figure Description

[0018] Figure 1This is a flowchart illustrating the implementation of a transient synchronization support method for an energy storage type dual-feed modulated camera according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the implementation of a transient synchronization support method for an energy storage type dual-feed accelerator camera according to another embodiment of the present invention. Figure 3 This is a control structure block diagram of a transient synchronization support method for an energy storage type doubly fed camera provided in an embodiment of the present invention; Figure 4 This is a stator current operating limit diagram of an energy storage type doubly fed camera provided in an embodiment of the present invention; Figure 5 This is a power grid structure diagram provided in an embodiment of the present invention; Figure 6 This is a comparison diagram of voltage support effect under shallow short-circuit fault provided by an embodiment of the present invention; Figure 7 This is a comparison diagram of frequency support effect under shallow short-circuit fault provided by an embodiment of the present invention; Figure 8 This is a comparison diagram of voltage support effect under deep short-circuit fault provided by an embodiment of the present invention; Figure 9 This is a comparison diagram of frequency support effect under deep short-circuit fault provided by an embodiment of the present invention; Figure 10 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] Currently, there is a lack of research on transient voltage-frequency synchronization support control strategies for energy storage-type doubly-fed induction generators (DFIGs), with existing research mainly focusing on wind turbines. According to wind power grid connection guidelines, when voltage dips and frequency disturbances occur in the power system, the turbine must preferentially inject reactive current into the grid in proportion to the voltage drop at the grid connection point. Based on this requirement, wind turbines can achieve voltage-frequency synchronization support for the grid by adjusting the reactive current proportionality coefficient K and limiting active power output.

[0022] The aforementioned wind turbine transient voltage frequency synchronization support control strategy has two problems when applied to energy storage-type doubly-fed synchronous condensers: (1) Coefficient K The selection did not take into account the system frequency state. The functional positioning and active power control objectives of wind turbine generators and energy storage-type doubly-fed synchronous condensers are different. As a power generation device, the active power output of wind turbine generators adopts maximum power point tracking control, while the active power output of energy storage-type doubly-fed synchronous condensers, as inertial response devices, needs to be adjusted according to the system frequency state.

[0023] (2) The wind power grid connection standard gives K The value range is not applicable to energy storage doubly-fed synchronous condensers (DFHCs). Because energy storage DFHCs possess high overload and strong support characteristics, the coefficient... K It should have a wider range of values; too small a range will waste its strong voltage support capability.

[0024] To address the aforementioned issues, this application provides a transient synchronization support method for a doubly fed energy storage camera based on an adaptive reactive current proportional coefficient. Figure 1 This is a schematic diagram illustrating the implementation process of a transient synchronization support method for an energy storage-type doubly-fed induction camera according to an embodiment of the present invention. Figure 1 As shown, it includes: Step S101: When voltage dips and frequency disturbances occur in the power system, obtain the normalized values ​​of voltage deviation, frequency deviation, and frequency change rate at the terminal of the energy storage type doubly fed synchronous condenser.

[0025] In this embodiment, the amplitude of the terminal voltage of the energy storage type doubly fed accelerator camera is monitored in real time. U s and grid frequency f t .

[0026] The magnitude of the voltage amplitude at the terminals of a doubly-fed synchronous condenser can be used to determine whether a voltage dip has occurred in the power system. For example, if 0.9... U N <U s < 1.1 U N If so, it is determined that no voltage drop has occurred; if U s < 0.9 U N Then it is determined that a voltage drop has occurred. U N This is the rated voltage.

[0027] When a voltage drop occurs in the power system, the voltage deviation normalization value is calculated by the deviation between the actual voltage at the generator terminal and the rated voltage, the frequency deviation normalization value is calculated by the deviation between the actual frequency of the system and the rated frequency, and the frequency change rate normalization value is calculated by the rate of change of the system frequency.

[0028] Step S102: Determine the adaptive reactive current proportional coefficient based on the normalized values ​​of voltage deviation, frequency deviation, and frequency change rate.

[0029] Because system voltage and frequency change dynamically during faults, the limitations of a fixed reactive current proportional coefficient make it difficult for energy storage-type doubly-fed synchronous condensers to adapt to different fault severity levels. To balance the active power output requirements of these devices as inertial response units, an adaptive reactive current proportional coefficient is needed. K c The output should change according to the system state to minimize the impact on active power output and retain output margin. This embodiment will... K c Designed as a function of voltage deviation, frequency deviation, and frequency change rate, to enable real-time adjustment of reactive current according to system requirements.

[0030] For example, the reactive current proportionality coefficient K c The expression is as follows:

[0031] in, K x Value to be adjusted; K 0 is the basic coefficient; K u This is the voltage deviation compensation coefficient; K f1 This is the frequency deviation compensation coefficient; K f2 This is the frequency change rate compensation coefficient; K 0、 K u , K f1 , K f2 All are greater than 0; x 1 represents the normalized value of the voltage deviation; x 2 represents the normalized value of the frequency deviation; x 3 represents the normalized value of the rate of change of frequency.

[0032] Step S103: Determine the dynamic reactive current increment based on the adaptive reactive current proportional coefficient and voltage sag depth; determine the target reactive current based on the dynamic reactive current increment and the reactive current output by the energy storage doubly fed induction generator before the voltage sag, so as to perform reactive power control on the energy storage doubly fed induction generator.

[0033] Here, an adaptive reactive current proportional coefficient is used. K c The dynamic reactive current increment Δ is obtained by calculating the voltage drop depth at the generator terminals. i q The reactive current output of the energy storage type doubly-fed synchronous condenser during normal operation before the voltage drop. I Summing by zero yields the reactive current that the synchronous condenser should output during the transient period. I q (Reactive current must not exceed the limit), thus completing the reactive current control process.

[0034] Step S104: By combining virtual inertia control with the limiting effect of adaptive reactive current proportional coefficient on active current, the target active current is obtained for active control of the energy storage type doubly fed camera.

[0035] In the active power control stage, based on the adaptive reactive current proportional coefficient, virtual inertia control is adopted in combination with the principles of reactive power priority and active power limiting to achieve frequency support.

[0036] For example, a doubly-fed synchronous condenser can provide active power support within the stator and rotor current constraints based on the magnitude of frequency disturbances:

[0037] in, i rd,ref The target active current; The active current is calculated based on the active power reference value given by virtual inertia control. P s,ref The active power reference value given for the energy storage type doubly fed camera for virtual inertia control; U s For the terminal voltage of the energy storage type doubly fed condenser; L s For stator inductance; L m For mutual inductance between the stator and rotor; I r,max This represents the maximum current in the rotor winding. U sf This refers to the per-unit value of the terminal voltage of a doubly fed synchronous condenser. I N This is the rated current of the energy storage type doubly fed synchronous condenser; ω s This is the synchronization angular frequency; I q0 The reactive current output by the energy storage type doubly fed synchronous condenser before the voltage drop; K c This is the adaptive reactive current proportional coefficient.

[0038] In the expression for the active current of a doubly fed synchronous condenser for energy storage It embodies the direct commands of virtual inertia control. This demonstrates the constraint relationship between voltage support and frequency support; this part represents the rotor current limit. Under the constraint of [specific constraints], the current capacity remaining after deducting the reactive current used for voltage support is available for active power output. When the system frequency drops significantly... K c This will reduce the priority of reactive power output by the energy storage-type doubly-fed synchronous condenser, thereby releasing more current capacity for active power output under current limit constraints, ensuring that frequency support capability is not sacrificed. Due to... K c Dynamic adaptability enables energy storage-type doubly-fed synchronous condensers to dynamically adjust their active and reactive power output ratios according to the real-time comprehensive state of the power grid, coordinating the two support behaviors during transient processes.

[0039] Based on the above, the voltage and frequency of the power system change dynamically during faults, and the limitations of a fixed reactive current proportional coefficient make it difficult for energy storage-type doubly-fed induction generators (DFIGs) to adapt to different fault levels. In this embodiment of the invention, when the power system experiences voltage dips and frequency disturbances, an adaptive reactive current proportional coefficient is constructed using the normalized values ​​of voltage deviation, frequency deviation, and frequency change rate at the DFIG terminal. In the reactive power control stage, the dynamic reactive current increment is determined based on the adaptive reactive current proportional coefficient and the voltage dip depth. The target reactive current is then determined based on the dynamic reactive current increment and the reactive current output by the DFIG before the voltage dip to perform reactive power control on the DFIG. In the active power control stage, the target active current is obtained by combining virtual inertia control with the limiting effect of the adaptive reactive current proportional coefficient on the active current to perform active power control on the DFIG. This embodiment achieves synchronous support for voltage and frequency, and the adaptive adjustment coefficient of reactive current is designed as a function of voltage deviation, frequency deviation, and frequency change rate. It can automatically adjust according to the real-time voltage and frequency status, enhancing the coordination capability of active and reactive power output of the energy storage type doubly fed camera.

[0040] In some embodiments, prior to step S102, it is also necessary to... K 0、 K u , K f1 , K f2 The settings are adjusted to meet engineering requirements. The adjustment process includes: I. Obtaining the stator overload factor of a doubly-fed synchronous condenser. m c and rotor overload multiple nc Preset stator overload multiple of wind turbine m w and rotor overload multiple n w And the minimum reactive current proportionality coefficient given by the wind turbine fault ride-through standard. K w,min With the maximum value K w,max ; Minimum limit of adaptive reactive current proportional coefficient for energy storage type doubly-fed synchronous condenser K c,min The selection references the technical requirements for wind farm connection to the power system, when the system voltage drops to 0.2. U N The reactive current output increment of the timing unit should not be lower than its lower limit, which can be used to determine K c,min :

[0041] Maximum limit of adaptive reactive current proportional coefficient for energy storage type doubly fed synchronous condenser K c,max The selection of a doubly-fed induction generator (DFIG) should refer to the requirements for preventing a sudden drop in the active power output of the unit during voltage faults. When the system voltage drops, to ensure that the steady-state active power output of the unit is not affected, the increase in reactive current output should not exceed its upper limit. Therefore, the following can be determined: K c,max :

[0042] two, K The value of 0 determines that the terminal voltage of the energy storage type doubly-fed accelerator camera is close to 0.9. U N The initial value of reactive power output at that time is determined to balance preventing excessive reactive power during voltage recovery with leveraging its strong voltage support capability. K 0 should be in K c Select a moderately smaller value within the range:

[0043] three, K u The setting is based on a scenario where the system only experiences a voltage drop. K c Only by K 0 and K u Decide, K u It is necessary to ensure K cIt increases with the depth of the voltage drop, and increases when the voltage drops to 0.2. U N To reach the maximum value, the following relationship should be satisfied:

[0044] Four, K f1 , K f2 The tuning must ensure that the voltage, frequency, and rate of change all reach their maximum values. K c The maximum value should be taken to prioritize voltage recovery; simultaneously, to utilize the rapid sensitivity of the frequency change rate to power demand, it should be given... K f2 Greater weighting to accelerate the response to frequency drops:

[0045] Figure 2 This is a schematic diagram illustrating the complete implementation process of a transient synchronization support method for an energy storage type doubly fed camera provided in another embodiment of the present invention. The method includes: (1) Obtain the magnitude of the terminal voltage of the energy storage type doubly fed condenser. U s With grid frequency f t ; (2) Determine the range of the voltage amplitude at the terminals of the energy storage type doubly-fed synchronous condenser. If it is 0.9... U N <U s < 1.1 U N Then proceed to step (3), if U s < 0.9 U N Proceed to step (4); (3) The reactive power control loop of the synchronous condenser adopts constant power control mode and adjusts the reactive power output by receiving instructions from the host computer; when there is no frequency disturbance, the active power control loop adopts constant speed control, and when the frequency disturbance crosses the dead zone, it switches to virtual inertia control and returns to step (1). (4) Obtain the normalized value of the terminal voltage deviation. x 1. Normalized value of power grid frequency deviation x 2 and the normalized value of the rate of change of frequency x 3; (5) Construct containing x 1. x 2 and x 3 Adaptive reactive current proportional coefficientK c ,in K c The range of values, the basic coefficients, and the compensation coefficients must meet the engineering requirements. (6) Adopt an adaptive reactive current proportional coefficient K c The dynamic reactive current increment Δ is obtained by calculating the system voltage sag depth. i q The output reactive current during normal operation I Summing 0 yields the reactive current that the synchronous condenser should output during the transient period. I q (Reactive current must not exceed the limit), thus completing the reactive power control process; (7) When the frequency is stable, the active power control link adopts constant speed control. When the frequency disturbance crosses the dead zone, the active power control link adopts virtual inertia control based on the adaptive reactive current proportional coefficient, combined with the principle of reactive priority and active power limit, to achieve voltage and frequency synchronous support and return to step (1).

[0046] See example 3. Figure 3 The block diagram of the energy storage type doubly fed synchronous condenser control of this method is shown, which illustrates the vector control structure of the synchronous condenser rotor-side converter.

[0047] like Figure 3 As shown: The reactive power control system has two control modes. When the system voltage is stable, the energy storage doubly-fed synchronous condenser adopts a constant power mode. Q s,ref In control mode, reactive power output is adjusted by receiving commands from the host computer. When both voltage and frequency drops occur simultaneously, the unit should prioritize its own reactive power output. In this case, the energy storage-type doubly-fed synchronous condenser adjusts its reactive power output based on the current voltage deviation and the adaptive reactive current proportional coefficient. K c Provides reactive power support.

[0048] That is, rotor reactive current command i rq,ref for:

[0049] In the formula, Q s,ref Given reactive power; i rq,ref The target reactive current for the rotor.

[0050] The active power control circuit also has two control modes. When the system frequency is stable, the energy storage doubly fed synchronous condenser adopts a constant speed. Control; when a frequency disturbance crosses the dead zone, it switches to power control mode, using active speed regulation to absorb and release active power, thereby generating virtual inertia to respond to frequency changes in the system. During frequency disturbances, the active power reference value of the energy storage doubly-fed induction generator is... P s,ref The upper limit of active power output is determined by the system frequency deviation and the rate of frequency change, and must also meet the following requirements:

[0051] In the formula, k 1. k 2 represents the droop coefficient and the virtual inertia coefficient, respectively. k 1. k 2 are all greater than 0.

[0052] That is, the energy storage type doubly-fed synchronous condenser can provide active power support within the stator and rotor current constraints according to the magnitude of frequency disturbances, and the target active current of the rotor... i rd,ref for:

[0053] Figure 4 The stator current operating limit diagram for a doubly fed synchronous condenser is given, and the stator and rotor current constraints are expressed as follows:

[0054] Relationship between stator current and rotor current in a doubly fed synchronous condenser for energy storage:

[0055] The determination of the stator current limit should satisfy the stator and rotor current constraints:

[0056] In the formula, i sd , i sq These are energy storage type doubly fed phase-shifting cameras and stator current, respectively. d , q Axial components; I r,max , I s,max These are the maximum current values ​​for the rotor winding and the stator winding, respectively.

[0057] like Figure 4 As shown, circle C 1. C 2 corresponds to the stator and rotor current constraints, respectively, and their intersection represents the energy storage type doubly-fed synchronous condenser. i sd - i sqThe operational region, therefore the envelope of this intersection is the energy storage type doubly-fed camera. i sd - i sq Operating limits. The horizontal axis in the graph represents the stator. q The axis represents the current; the positive half-axis represents the inductive reactive power supplied to the grid, and the negative half-axis represents the inductive reactive power absorbed from the grid; the vertical axis represents the stator current. d The positive half-axis indicates that the unit is operating in motor mode, and the negative half-axis indicates that it is operating in generator mode.

[0058] by Figure 5 The power grid structure shown is simulated. The system includes a 30MW synchronous motor SG, a 150MW active load L1 and a 90MW, 10Mvar load L2, a wind farm with an installed capacity of 60 units × 1.5MW / unit, and a 10MW energy storage doubly fed synchronous condenser.

[0059] The simulation system is configured as follows: Initially, the system operates stably; shallow three-phase short-circuit fault scenarios and deep three-phase short-circuit fault scenarios are set up respectively, and the voltage and frequency synchronization support effects of the synchronous support strategy with adaptive reactive current proportional coefficient, the synchronous support strategy with constant reactive current proportional coefficient, and the energy storage-type doubly-fed induction generator without active support are compared; among these, the following settings are determined: K c,min =3.5, K c,max =11, K 0 = 5.5 K u =14.5, K f1 =14.5, K f2 =6, take the system frequency deviation ∆ f max With ∆ f min Using 0.5Hz and 0Hz as the reference frequencies, and selecting the maximum and minimum values ​​of the frequency change rate as 2Hz / s and 0Hz / s respectively, the adaptive reactive current proportional coefficient can be obtained. K c The quantitative expression is given. A shallow three-phase short-circuit fault occurs at 15s using a fault occurrence device, and the fault is cleared after 600ms. The reactive current proportional coefficient of the constant coefficient control strategy is taken as... K c,min Under a shallow short-circuit fault, the system voltage drops to a minimum of 0.75V. U N The frequency dropped to a minimum of 49.82Hz, as shown in the simulation results. Figure 6 and Figure 7 As shown, the voltageU Active power P With reactive power Q The value is per unit. A deep three-phase short-circuit fault occurs at 15 seconds using a fault occurrence device, and the fault clears after 600 ms. The reactive current proportional coefficient of the constant coefficient control strategy is taken as... K c,max Under a deep short-circuit fault, the system voltage drops to a minimum of 0.5 ohms. U N The frequency dropped to a minimum of 49.52Hz, as shown in the simulation results. Figure 8 and Figure 9 As shown, the voltage U Active power P With reactive power Q This is the per-unit value.

[0060] Figure 6 , Figure 7 This study demonstrates the verification of voltage and frequency support effects under shallow short-circuit faults, comparing the voltage and frequency synchronization support effects of synchronous support strategies using adaptive reactive current proportional coefficients, constant reactive current proportional coefficients, and no active support from the energy storage-type doubly-fed induction generator (DFIG). Regarding voltage support, when the energy storage-type DFIG uses a constant coefficient control strategy, the unit's voltage support effect is weak due to the small reactive current proportional coefficient. However, when the energy storage-type DFIG uses an adaptive coefficient control strategy, the system's active power demand is lower in this scenario, and according to parameter tuning principles, the unit will prioritize reactive power output when facing the same degree of voltage and frequency dips. Therefore, the unit actively increases... K c This allows for a larger reactive current output, effectively boosting the system voltage. Regarding frequency support, the system frequency drop is shallow in this scenario, resulting in a smaller active power output from the generator. When the energy storage-type doubly-fed synchronous condenser adopts an adaptive coefficient control strategy, the coefficient should be appropriately increased. K c It does not affect the active power output in the active power limiting stage. Therefore, the adaptive coefficient control strategy and the fixed coefficient control strategy exhibit the same frequency support effect, both providing strong frequency support to the system.

[0061] Figure 8 , Figure 9 This study demonstrates the effectiveness of voltage and frequency support under deep short-circuit faults, comparing the voltage and frequency synchronization support effects of a synchronous support strategy using an adaptive reactive current proportional coefficient, a synchronous support strategy using a constant reactive current proportional coefficient, and a doubly-fed induction generator (DFIG) without active support. At 15 seconds, the system voltage experienced a sudden drop. During the initial fault phase (15s~15.2s), the system frequency change rate was large, but the frequency deviation was small. Therefore, the adaptive coefficient control strategy employed by the DFIG demonstrates superior performance.K c The maximum value is selected to provide strong voltage and frequency support for the system, ensuring rapid voltage recovery. In the later stages of the fault (15.2s~15.6s), the system frequency deviation begins to increase. Because the energy storage-type doubly-fed synchronous condenser uses a fixed-coefficient synchronous support control strategy that does not consider the system's frequency state, from... Figure 7 As can be seen, at this point, the full reactive power output of the energy storage-type doubly-fed synchronous condenser results in an extremely low upper limit of the unit's active power output, making it unable to provide suitable frequency support to the system; while the energy storage-type doubly-fed synchronous condenser, when employing an adaptive coefficient control strategy, can actively reduce... K c To reduce reactive power output, a suitable margin is provided for the generator unit in the active power limiting stage, thereby providing stronger frequency support to the system and preventing the system frequency from being too low. The voltage deviation decreases rapidly upon fault clearance, but due to the slow frequency recovery speed, the energy storage-type doubly-fed synchronous condenser still needs to provide strong frequency support to the system. Meanwhile, in suppressing voltage overshoot, the constant-coefficient control strategy... K c Constantly using the maximum value will lead to excessive reactive power in the system due to reactive power response lag, resulting in severe overvoltage problems; while the adaptive synchronous support control strategy... K c The reactive power output of the energy storage type doubly fed synchronous condenser is small when the voltage recovers and the fault is cleared, which effectively improves the system overvoltage problem.

[0062] Based on simulation results Figure 6 , Figure 7 , Figure 8 and Figure 9 Verification of voltage support effectiveness and frequency support effectiveness shows that when the frequency remains stable or is minimal during the fault duration, K c The larger value is taken to provide strong voltage support to the power grid; when the frequency disturbance is large during the fault duration... K c Actively reduce reactive power output to appropriately lower reactive power output, and provide a suitable margin for the unit during active power limiting; during fault recovery. K c This reduces reactive power excess in the system, improving the overall stability of the grid voltage and frequency. In summary, the control strategy proposed in this application can adaptively adjust according to the system voltage and frequency status. K c Compared with the fixed coefficient control strategy, it has a better synchronous support effect when facing short-circuit faults of different degrees.

[0063] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0064] Figure 10 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. For example... Figure 10 As shown, the electronic device 10 of this embodiment includes a processor 100 and a memory 101. The memory 101 stores a computer program 102. When the processor 100 executes the computer program 102, it implements the steps in the various method embodiments described above. The computer program 102 can be divided into one or more modules / units, which are stored in the memory 101 and executed by the processor 100 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 102 in the electronic device 10.

[0065] Electronic device 10 may include, but is not limited to, processor 100 and memory 101. Those skilled in the art will understand that... Figure 10 This is merely an example of electronic device 10 and does not constitute a limitation on electronic device 10. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 10 may also include input / output devices, network access devices, buses, etc.

[0066] The processor 100 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0067] The memory 101 can be an internal storage unit of the electronic device 10, such as a hard disk or RAM of the electronic device 10. The memory 101 can also be an external storage device of the electronic device 10, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the electronic device 10. Furthermore, the memory 101 can include both internal and external storage units of the electronic device 10. The memory 101 is used to store the computer program 102 and other programs and data required by the electronic device 10. The memory 101 can also be used to temporarily store data that has been output or will be output.

[0068] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0069] This invention also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0070] This invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0071] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0072] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0073] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A transient synchronization support method for an energy storage type doubly-fed induction camera, characterized in that, The method comprises the following steps: When voltage sag and frequency disturbance occur in a power system, a voltage deviation normalized value, a frequency deviation normalized value and a frequency change rate normalized value of a terminal of a storage-type doubly-fed phase modifier are obtained; An adaptive reactive current proportional coefficient is determined according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value; A dynamic reactive current increment is determined according to the adaptive reactive current proportional coefficient and a voltage sag depth, and a target reactive current is determined according to the dynamic reactive current increment and a reactive current output by the storage-type doubly-fed phase modifier before voltage sag, so as to perform reactive control on the storage-type doubly-fed phase modifier; A target active current is obtained by combining virtual inertia control and amplitude limiting of the adaptive reactive current proportional coefficient on the active current, so as to perform active control on the storage-type doubly-fed phase modifier.

2. The method of claim 1, wherein the energy storage doubly-fed phase modifier transient synchronous support is characterized by, The step of determining the adaptive reactive current proportional coefficient according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value comprises the following steps: Determining an adjusted value of an adaptive reactive current proportionality coefficient ; If the to-be-adjusted value is less than or equal to a minimum limit value of the adaptive reactive current proportional coefficient, the minimum limit value is determined as the adaptive reactive current proportional coefficient; If the to-be-adjusted value is greater than or equal to a maximum limit value of the adaptive reactive current proportional coefficient, the maximum limit value is determined as the adaptive reactive current proportional coefficient; If the to-be-adjusted value is between the minimum limit value and the maximum limit value, the to-be-adjusted value is determined as the adaptive reactive current proportional coefficient. wherein K x is a value to be adjusted; K 0 is a basic coefficient; K u is a voltage deviation compensation coefficient; K f1 is a frequency deviation compensation coefficient; K f2 is a frequency change rate compensation coefficient; K 0, K u , K f1 , K f2 are all greater than 0; x 1 is a voltage deviation normalization value; x 2 is a frequency deviation normalization value; x 3 is a frequency change rate normalization value.

3. The method according to claim 1 or 2, characterized in that, Before the step of determining the adaptive reactive current proportional coefficient according to the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value, the method further comprises the following steps: Minimum and maximum limit values of the adaptive reactive current proportional coefficient of the storage-type doubly-fed phase modifier are obtained; The basic coefficient, the voltage deviation compensation coefficient, the frequency deviation compensation coefficient and the frequency change rate compensation coefficient are determined according to the minimum and maximum limit values.

4. The method of claim 3, wherein the energy storage doubly-fed phase modifier transient synchronization support is characterized by, The step of obtaining the minimum and maximum limit values of the adaptive reactive current proportional coefficient of the storage-type doubly-fed phase modifier comprises the following steps: obtaining a stator overload multiple of the energy storage type doubly-fed phase modifier m c and a rotor overload multiple n c , a stator overload multiple of a preset wind turbine m w and a rotor overload multiple n w , and a minimum value of a reactive current proportion coefficient given by the wind turbine fault ride through criterion K w,min and a maximum value K w,max ; According to determining a minimum limit value of the adaptive reactive current proportional coefficient of the energy storage type doubly-fed phase modifier; According to determining the maximum limit value of the adaptive reactive current proportional coefficient of the energy storage type doubly-fed phase modifier; wherein K c,min is the minimum limit value, K c,max is the maximum limit value.

5. The method of claim 4, wherein the energy storage doubly-fed phase modifier transient synchronization support is characterized by, The step of determining the basic coefficient, the voltage deviation compensation coefficient, the frequency deviation compensation coefficient and the frequency change rate compensation coefficient according to the minimum and maximum limit values comprises the following steps: According to determining the base coefficients; According to The value range of the voltage deviation compensation coefficient is determined, and the voltage deviation compensation coefficient is determined according to the value range of the voltage deviation compensation coefficient. According to determining a value range of the frequency deviation compensation coefficient and the frequency change rate compensation coefficient, and determining the frequency deviation compensation coefficient and the frequency change rate compensation coefficient according to the value range of the frequency deviation compensation coefficient and the frequency change rate compensation coefficient; wherein K 0 is a base coefficient; K u is a voltage deviation compensation coefficient; K f1 is a frequency deviation compensation coefficient; K f2 is a frequency change rate compensation coefficient; K 0, K u , K f1 , K f2 are all greater than 0.

6. The energy storage doubly-fed phase modifier transient synchronous support method of claim 1 or 2, wherein, The step of obtaining the target active current by combining virtual inertia control and amplitude limiting of the adaptive reactive current proportional coefficient on the active current comprises the following steps: According to obtaining a target active current; wherein, i rd,ref is the target active current; is the active current calculated based on the active power reference value given by the virtual inertia control; P s,ref is the active power reference value of the energy storage doubly-fed phase modifier given by the virtual inertia; U s is the terminal voltage of the energy storage doubly-fed phase modifier; L s is the stator inductance; L m is the mutual inductance between the stator and the rotor; I r,max is the maximum current of the rotor winding; U sf is the terminal voltage of the energy storage doubly-fed phase modifier; I N is the rated current of the energy storage doubly-fed phase modifier; ω s is the synchronous angular frequency; I q0 is the reactive current output by the energy storage doubly-fed phase modifier before the voltage drop; K c is the adaptive reactive current proportionality coefficient.

7. The method of claim 1 or 2, wherein, The step of obtaining the voltage deviation normalized value, the frequency deviation normalized value and the frequency change rate normalized value of the terminal of the storage-type doubly-fed phase modifier comprises the following steps: The terminal voltage of the storage-type doubly-fed phase modifier and the grid frequency are obtained; The voltage deviation normalized value is determined according to the terminal voltage of the storage-type doubly-fed phase modifier, and the frequency deviation normalized value and the frequency change rate normalized value are determined according to the grid frequency.

8. The method of claim 7, wherein the energy storage doubly-fed phase modifier transient synchronization support is characterized by, The method further comprises the following steps: When the frequency is stable, fixed-speed active control is performed on the storage-type doubly-fed phase modifier. When the voltage dip does not occur in the power system, but the frequency disturbance crosses the dead zone, the active power control is performed on the energy storage type doubly-fed phase modifier according to the given active current of the virtual inertia control.

9. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the method in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the method in any one of claims 1 to 8.

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