Inertia support control method and system of high-inertia energy storage type synchronous condenser

Abstract

The application discloses an inertia support control method and system of a high-inertia energy storage type synchronous condenser, comprising: when the grid voltage is greater than or equal to a preset voltage threshold, determining a grid frequency deviation based on the grid frequency, and judging whether the frequency deviation exceeds a dead zone range, and obtaining a judgment result; when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation function are put into operation, an active current instruction value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current instruction value; the rotor speed is obtained in real time, when the rotor speed reaches a rotor speed limit value, the active output instruction is set to zero and the dead zone range is adjusted, until the rotor speed returns to a preset range, the dead zone range is restored to normal, and the active output instruction is unlocked.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor and electrical appliances and power electronic control technology, and more particularly, to an inertia support control method and system for a high-inertia energy storage type synchronous phase modifier. BACKGROUND

[0002] With the continuous increase of new energy in the new power system, the voltage and inertia support capability of the power supply side is decreasing, and the synchronous phase modifier becomes a key device to ensure the sustainable development of new energy. The synchronous phase modifier can be divided into large-capacity centralized and small-capacity distributed, among which the large-capacity centralized phase modifier is usually configured in the DC receiving end converter station to improve the voltage stability level of the system, and the small-capacity distributed phase modifier can be configured in the new energy station, which can not only play the role of dynamic reactive power reserve, but also provide voltage support for new energy power stations in the process of sub-transient, transient and steady state.

[0003] The synchronous phase modifier has inertia response characteristics, that is, the rotor has rotational inertia and rotor winding flux linkage conservation. When the system is disturbed, the size and phase of the equivalent potential of the synchronous phase modifier do not change suddenly, showing the characteristics of a voltage source. The distributed phase modifier is usually connected to the node of the power grid and the new energy station, and the electrical distance between them is relatively short. This characteristic determines that the synchronous phase modifier will bear the active power disturbance in the system transient process together with the synchronous generator. The synchronous phase modifier provides certain inertia support during system failure, but also may cause the risk of power angle instability of the phase modifier itself due to the continuous active power surplus or deficiency of the system.

[0004] The low voltage, overvoltage and inertia support problems of new energy stations have become the main limiting factors affecting the consumption of new energy, and will become more and more serious with the rapid development of new energy installations in the next five years. The national standard "Guidelines for Safety and Stability of Power System" stipulates that in high-proportion new energy areas, new energy stations should provide voltage support and certain inertia support to the system. In the Qinghai power grid new energy concentrated sending area, 21 distributed phase modifiers have been put into operation, and several phase modifiers have also been put into operation in Jibei power grid. The synchronous phase modifier has become the main means to solve the overvoltage and low voltage problems in some areas.

[0005] At present, the synchronous phase modifier connected to the grid mainly solves the voltage stability problem, and there is no synchronous phase modifier with active inertia support and primary frequency modulation capability. There is no clear control method for inertia support and primary frequency modulation of the synchronous phase modifier, and no synchronous phase modifier rotor variable speed operation logic and criterion are proposed.

[0006] Therefore, there is a need for an inertia support control method for a high-inertia energy storage type synchronous phase modifier. SUMMARY

[0007] The application provides an inertia support control method and system for a high-inertia energy storage type synchronous condenser, to solve the problem of how to realize inertia support and primary frequency modulation control of the synchronous condenser.

[0008] To solve the above problems, according to one aspect of the application, a kind of inertia support control method for high-inertia energy storage type synchronous condenser, the method comprises:

[0009] When the grid voltage is greater than or equal to the preset voltage threshold, the grid frequency deviation is determined based on the grid frequency, and whether the frequency deviation exceeds the dead zone range is judged, and a judgment result is obtained;

[0010] When the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation function are put into, the active current command value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current command value;

[0011] The rotor speed is obtained in real time, and when the rotor speed reaches the rotor speed limit value, the active output command is set to zero and the dead zone range is adjusted, until the rotor speed returns to the preset range, the dead zone range is restored to normal, and the active output command is unlocked.

[0012] Preferably, wherein the active current command value is generated according to the frequency deviation, comprising:

[0013] Enter the inertia support mode, generate the first active current command value according to the frequency deviation, comprising:

[0014]

[0015] Enter the primary frequency modulation mode, generate the second active current command value according to the frequency deviation, comprising:

[0016]

[0017] Determine the active current command value according to the sum of the first active current command value and the second active current command value;

[0018] Wherein, P1 is the active power command value generated by the inertia support mode; f is the actual grid frequency; f n is the rated frequency of the grid; K i is the inertia support mode coefficient; T i is the inertia support mode time constant; s is the Laplace operator; f and f n The difference between f and f is the frequency deviation; P2 is the active power command value generated by the primary frequency modulation mode; K p is the primary frequency modulation mode coefficient; T p is the primary frequency modulation mode coefficient.

[0019] Preferably, when the rotor speed reaches the rotor speed limit value, the active output instruction is set to zero and the dead zone range is adjusted, until the rotor speed returns to the preset range, the dead zone range is restored to normal, comprising:

[0020] When the rotor speed decreases to the minimum rotor speed, the active output instruction is set to zero, the frequency difference dead zone f db+ One-way zeroing, until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, the speed increases, and when the rotor speed returns to the rated speed, the dead zone returns to normal;

[0021] When the rotor speed increases to the maximum rotor speed, the active output instruction is set to zero, the frequency difference dead zone f db- One-way zeroing, until the grid frequency is less than 50Hz, the rotor sends active power to the grid, the speed decreases, and when the rotor speed returns to the rated speed, the dead zone returns to normal.

[0022] Preferably, wherein the minimum rotor speed = rated speed of the phase modifier × (1-| minimum rotor speed difference |); the maximum rotor speed = rated speed of the phase modifier × (1+ maximum rotor speed difference).

[0023] Preferably, wherein the method further comprises:

[0024] When the grid voltage is greater than or equal to the preset voltage threshold, the voltage control is performed to obtain the reactive current instruction value;

[0025] Based on the reactive current instruction value and the unlocked active current output instruction, a modulation wave is generated to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, to send reactive power or absorb and release active power during grid failure, to realize dual support of voltage / inertia.

[0026] According to another aspect of the present application, a voltage and inertia support control system for a high inertia energy storage type synchronous phase modifier is provided, the system comprising:

[0027] A judgment unit is configured to determine the grid frequency deviation based on the grid frequency when the grid voltage is greater than or equal to the preset voltage threshold, and to determine whether the frequency deviation exceeds the dead zone range to obtain a judgment result;

[0028] An active current instruction value determination unit is configured to, when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation function is put into operation, the active current instruction value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current instruction value;

[0029] The control unit is configured to acquire the rotor speed in real time, set the active power output instruction to zero and adjust a dead zone range when the rotor speed reaches a rotor speed limit value, restore the dead zone range to normal and unlock the active power output instruction when the rotor speed returns to a preset range.

[0030] Preferably, the active current instruction value determination unit generates the active current instruction value according to the frequency deviation, including:

[0031] In the inertia support mode, the first active current instruction value is generated according to the frequency deviation, including:

[0032]

[0033] In the primary frequency regulation mode, the second active current instruction value is generated according to the frequency deviation, including:

[0034]

[0035] The active current instruction value is determined according to the sum of the first active current instruction value and the second active current instruction value;

[0036] Wherein, P1 is the active power instruction value generated by the inertia support mode; f is the actual frequency of the power grid; f n is the rated frequency of the power grid; K i is the inertia support mode coefficient; T i is the inertia support mode time constant; s is the Laplace operator; the difference between f and f n is the frequency deviation; P2 is the active power instruction value generated by the primary frequency regulation mode; K p is the primary frequency regulation mode coefficient; T p is the primary frequency regulation mode coefficient.

[0037] Preferably, the control unit sets the active power output instruction to zero and adjusts the dead zone range when the rotor speed reaches the rotor speed limit value, restores the dead zone range to normal and unlocks the active power output instruction when the rotor speed returns to the preset range, including:

[0038] When the rotor speed decreases to the minimum rotor speed, the active power output instruction is set to zero, the frequency difference dead zone f db+ is set to zero in a single direction, until the grid frequency is greater than 50 Hz, the rotor absorbs active power from the grid to increase the speed, and when the rotor speed returns to the rated speed, the dead zone returns to normal;

[0039] When the rotor speed increases to the maximum rotor speed, the active power output instruction is set to zero, the frequency difference dead zone f db- is set to zero in a single direction, until the grid frequency is less than 50 Hz, the rotor sends active power to the grid to reduce the speed, and when the rotor speed returns to the rated speed, the dead zone returns to normal.

[0040] Preferably, wherein the minimum speed = rated speed of the phase modifier x (1- |minimum slip rate|); the maximum speed = rated speed of the phase modifier x (1+ maximum slip rate).

[0041] Preferably, wherein the system further comprises:

[0042] a voltage control unit configured to perform constant voltage control to obtain a reactive current instruction value when the grid voltage is greater than or equal to a preset voltage threshold;

[0043] a converter control unit configured to generate a modulation wave based on the reactive current instruction value and the unlocked active current output instruction, to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, to emit reactive power or absorb and release active power during grid failure, and to achieve dual support of voltage / inertia.

[0044] Based on another aspect of the present application, the present application provides a computer readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the steps of any one of the inertia support control methods of the high inertia energy storage type synchronous phase modifier.

[0045] Based on another aspect of the present application, the present application provides an electronic device comprising:

[0046] the above-mentioned computer readable storage medium; and

[0047] one or more processors configured to execute the program in the computer readable storage medium.

[0048] The application provides an inertia support control method and system of a high-inertia energy storage type synchronous phase modifier, comprising: when the grid voltage is greater than or equal to a preset voltage threshold, determining a grid frequency deviation based on the grid frequency, and judging whether the frequency deviation exceeds a dead zone range, and obtaining a judgment result; when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation function are put into operation, the active current instruction value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current instruction value; the rotor speed is obtained in real time, when the rotor speed reaches the rotor speed limit value, the active output instruction is set to zero and the dead zone range is adjusted, until the rotor speed returns to the preset range, the dead zone range is restored to normal, and the active output instruction is unlocked. The high-inertia energy storage type synchronous phase modifier can provide the ability of active inertia support, can absorb or release the kinetic energy stored in the rotor through the variable speed operation of the rotor, reduces the transient power angle instability risk of the phase modifier, improves the stable operation level of the grid, and improves the new energy consumption utilization level; provides a new implementation method for the new energy station to meet the voltage and inertia support at the same time, solves the problem that the new energy station needs to be equipped with multiple sets of equipment, and reduces the investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0049] The exemplary embodiments of the present application can be more completely understood by reference to the following drawings:

[0050] Figure 1 A flowchart of the inertia support control method 100 of the high-inertia energy storage type synchronous phase modifier according to the embodiment of the present application;

[0051] Figure 2 A circuit schematic diagram of the high-inertia energy storage type synchronous phase modifier according to the embodiment of the present application;

[0052] Figure 3 A structural schematic diagram of the high-inertia energy storage type synchronous phase modifier according to the embodiment of the present application;

[0053] Figure 4 A structural schematic diagram of generating an active current instruction based on the inertia support and primary frequency modulation mode according to the embodiment of the present application;

[0054] Figure 5 A structural schematic diagram of generating a reactive current instruction by the voltage / reactive power control mode according to the embodiment of the present application;

[0055] Figure 6 A flowchart of voltage and inertia support control of the high-inertia energy storage type synchronous phase modifier according to the embodiment of the present application;

[0056] Figure 7 A running state quantity change schematic diagram of the high-inertia energy storage type synchronous phase modifier according to the embodiment of the present application;

[0057] Figure 8 This is a schematic diagram of the inertia support control system 800 of a high-inertia energy storage synchronous condenser according to an embodiment of the present invention. Detailed Implementation

[0058] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0059] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0060] Figure 1 This is a flowchart of an inertia support control method 100 for a high-inertia energy storage synchronous condenser according to an embodiment of the present invention. Figure 1 As shown, the inertia support control method for high-inertia energy storage synchronous condensers provided by this invention can provide active inertia support capabilities. It can absorb or release kinetic energy stored in the rotor to the grid through rotor speed-changing operation, reducing the risk of transient power angle instability of the synchronous condenser, improving the stable operation level of the grid, and enhancing the utilization level of new energy sources. It provides a new method for new energy power plants to simultaneously meet voltage and inertia support requirements, solving the problem of needing multiple sets of equipment for new energy power plants and reducing investment costs. The inertia support control method 100 for high-inertia energy storage synchronous condensers provided by this invention starts from step 101. In step 101, when the grid voltage is greater than or equal to a preset voltage threshold, the grid frequency deviation is determined based on the grid frequency, and it is determined whether the frequency deviation exceeds the dead zone range, obtaining the determination result.

[0061] In step 102, when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency regulation functions are activated, an active current command value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current command value.

[0062] Preferably, generating the active current command value based on the frequency deviation includes:

[0063] entering the inertia support mode, generating a first active current instruction value according to the frequency deviation, comprising:

[0064]

[0065] entering the primary frequency modulation mode, generating a second active current instruction value according to the frequency deviation, comprising:

[0066]

[0067] determining the active current instruction value according to the sum of the first active current instruction value and the second active current instruction value;

[0068] wherein P1 is the active power instruction value generated by the inertia support mode; f is the actual frequency of the power grid; f n is the rated frequency of the power grid; K i is the inertia support mode coefficient; T i is the inertia support mode time constant; s is the Laplace operator; the difference between f and f n is the frequency deviation; P2 is the active power instruction value generated by the primary frequency modulation mode; K p is the primary frequency modulation mode coefficient; T p is the primary frequency modulation mode coefficient.

[0069] In the application, the high-inertia energy storage type synchronous phase modifier motor part is a traditional synchronous motor, the converter part is composed of a back-to-back grid-side inverter and a machine-side inverter, both of which have bidirectional active power flow capability, the grid frequency and phase angle are obtained through a phase-locked loop module; the rotor speed change can be used to absorb or release a certain amount of active power in a short time to realize inertia and primary frequency modulation support. The initial running state of the phase modifier can be set, such as the delay phase reactive power, the advance phase reactive power, the slip rate, the inertia and the primary frequency modulation dead zone; the control mode of the phase modifier can be set, such as the constant voltage control and the constant reactive power control.

[0070] The high-inertia energy storage type synchronous phase modifier converter control system is composed of two feedback loops of an external power loop and an internal current loop, the overall block diagram is shown in Figure 2 The generation of the active current instruction value includes the inertia support mode and the primary frequency modulation mode, and the generation of the reactive instruction includes the constant reactive control mode and the constant voltage control mode. The structure of the high-inertia energy storage type synchronous phase modifier converter control system is shown in Figure 3 .

[0071] In the application, the high-inertia energy storage type synchronous phase modifier is set with a frequency dead zone [f db- ,f db+The power grid frequency can be calculated by a phase-locked loop. The power grid frequency deviation fluctuates within a frequency dead zone range, and the rotor speed of the phase modifier is unchanged. When the power grid frequency deviation exceeds the set frequency dead zone, the inertia and primary frequency modulation function is put into operation to emit or absorb active power instructions. When the power grid frequency returns to the dead zone range, the active power instruction is locked.

[0072] The rated speed and maximum slip rate of the synchronous motor can be obtained according to the motor design scheme of the high-inertia energy storage type synchronous phase modifier. The minimum speed is the rated speed of the phase modifier multiplied by (1-|minimum slip rate|); and the maximum speed is the rated speed of the phase modifier multiplied by (1+maximum slip rate). For example, the rated speed of the high-inertia energy storage type synchronous phase modifier is 3000r / min, the maximum slip rate is [-0.12, 0.15], and the maximum speed variation range is [2640, 3450]r / min. The rotor speed can be stably operated within the range, and the active power instruction is zero when the limit value is reached.

[0073] In combination with Figure 4 In the application, for the inertia support mode, the phase modifier provides certain inertia support for the power grid when the system frequency is disturbed. A virtual inertia support link is added in the control system. When the system frequency is disturbed, the control system generates a reference value of the active power of the phase modifier based on the rate of change of the power grid frequency, and then generates an active current instruction through a proportional-integral link to make the rotor speed increase or decrease additionally and absorb or release more active power, thereby realizing additional inertia support. The first active current instruction value generated at this time is:

[0074]

[0075]

[0076] Wherein, P1 is the active power instruction value generated through the inertia support mode; T jv is the virtual inertia time constant of the high-inertia energy storage type synchronous phase modifier; f is the actual frequency of the power grid; f n is the rated frequency of the power grid; K i is the inertia support mode coefficient; T i is the inertia support mode time constant; and s is the Laplace operator.

[0077] In the application, the primary frequency modulation mode plays a role in the frequency disturbance process. When the system frequency deviation exceeds the frequency dead zone, the rotor speed changes to absorb or release active power, and the generated active power reference value is proportional to the frequency deviation. The second active current instruction value generated is:

[0078]

[0079] wherein P2 is the active power command value generated by the primary frequency modulation mode; f is the actual grid frequency; f n is the grid rated frequency; K p is the primary frequency modulation mode coefficient; T p is the primary frequency modulation mode coefficient; s is the Laplace operator.

[0080] In step 103, the rotor speed is acquired in real time, when the rotor speed reaches the rotor speed limit value, the active output command is set to zero and the dead zone range is adjusted, until the rotor speed returns to the preset range, the dead zone range is restored to normal, and the active output command is unlocked.

[0081] Preferably, wherein the active output command is set to zero and the dead zone range is adjusted when the rotor speed reaches the rotor speed limit value, until the rotor speed returns to the preset range, the dead zone range is restored to normal, comprising:

[0082] When the rotor speed is reduced to the minimum rotor speed, the active output command is set to zero, the frequency difference dead zone f db+ is set to zero in a single direction, until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, the speed is increased, and when the rotor speed returns to the rated speed, the dead zone is restored to normal;

[0083] When the rotor speed is increased to the maximum rotor speed, the active output command is set to zero, the frequency difference dead zone f db- is set to zero in a single direction, until the grid frequency is less than 50Hz, the rotor sends active power to the grid, the speed is reduced, and when the rotor speed returns to the rated speed, the dead zone is restored to normal.

[0084] Preferably, wherein the minimum rotor speed = rated speed of the phase modifier × (1-| minimum rotor speed difference |); the maximum rotor speed = rated speed of the phase modifier × (1+ maximum rotor speed difference).

[0085] In the present application, when the grid frequency is lower than the lower limit of the frequency dead zone, the rotor speed is reduced to release active power, when the rotor speed is reduced to the minimum value, the active output command is set to zero, so that the inner rotor cannot be lower than the minimum speed; and the frequency difference dead zone f db+ is set to zero in a single direction, i.e. there is no dead zone in the direction of frequency increase; when the grid frequency is higher than 50Hz, the rotor absorbs active power from the grid, the speed is increased; when the rotor speed returns to the rated speed, the dead zone is restored to normal.

[0086] When the grid frequency is higher than the upper limit of the frequency dead zone, the rotor speed is increased to absorb active power, when the rotor speed is increased to the maximum value, the active output command is set to zero, so that the inner rotor cannot be higher than the maximum speed; the frequency difference dead zone f db-Single direction zero, that is, no dead zone in the frequency reduction direction; after the grid frequency is lower than 50Hz, the rotor sends active power to the grid to reduce the speed; when the rotor speed recovers to the rated speed, the dead zone returns to normal.

[0087] The final rotor speed recovers to a reasonable interval, and the active output instruction in both directions is unlocked.

[0088] Preferably, wherein the method further comprises:

[0089] When the grid voltage is greater than or equal to the preset voltage threshold, the voltage control is performed to obtain the reactive current instruction value;

[0090] Based on the reactive current instruction value and the unlocked active current output instruction, a modulation wave is generated to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, send reactive power or absorb and release active power during grid failure, and realize dual support of voltage / inertia.

[0091] In combination Figure 5 As shown in the figure, in the application, the voltage / reactive power control mode of the high inertia energy storage type synchronous phase modifier can be divided into constant voltage control and constant reactive power control. The constant voltage control refers to generating a reactive current instruction reference value according to the deviation value of the reference value of the controlled grid voltage bus and the actual grid voltage. The constant reactive power control refers to that when the phase modifier is connected to the grid, the upper computer issues a reactive instruction, and according to the demand of the grid, the phase modifier can be operated in zero reactive, leading phase and lagging phase three states, and after receiving the instruction of the dispatching system, the reactive current can be increased or decreased, and then the output reactive value can be changed. In the steady state, constant reactive power control or constant voltage control can be performed, and in the fault condition, voltage control can be performed.

[0092] The high inertia energy storage type synchronous phase modifier based on the application can realize voltage and inertia support control at the same time, and the logic judgment process is as shown in the figure. Figure 6 When the grid voltage is less than 0.8pu, the active current is locked, and only the reactive current is generated based on the voltage control; when the grid voltage is less than or equal to 0.8pu, the active current and the reactive current can be generated at the same time, wherein the active current is generated based on the grid frequency, and finally the modulation wave is generated based on the reactive current instruction value and the unlocked active current output instruction to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, send reactive power or absorb and release active power during grid failure, and realize dual support of voltage / inertia.

[0093] In the embodiment of the application, the operating data among the grid frequency, the high inertia energy storage type synchronous phase modifier output active and the rotor speed in actual operation is as shown in the figure. Figure 7 Combining the grid operating conditions, the following various operating states can be obtained:

[0094] 1) Start to t1 stage, grid frequency fluctuates in dead band range, converter has no active output;

[0095] 2) t1 to t2 stage, grid frequency is lower than 50Hz, when the difference between grid frequency and given value exceeds f db- , inertia control action, control system generates active current command according to frequency difference command, rotor decelerates, outputs active to system;

[0096] 3) t2 to t3 stage, because rotor speed reduces to the lowest value, active output command is zero, so that inner rotor cannot be lower than the lowest speed; frequency difference dead band f db+ is set to zero in one direction, i.e. no dead band in frequency rising direction;

[0097] 4) t3 to t4 stage, grid frequency is lower than 50Hz, when grid frequency gradually recovers to 50Hz, rotor speed still keeps at the lower limit value;

[0098] 5) t4 to t5 stage, after grid frequency is higher than 50Hz, rotor absorbs active from grid, so that speed increases. When rotor speed recovers to rated speed, dead band recovers to normal;

[0099] 6) t5 to t8 stage, grid frequency fluctuates in dead band range, converter has no active output;

[0100] 7) t8 to t9 stage, grid frequency is higher than 50Hz, when the difference between grid frequency and given value exceeds f db+ , inertia control action, control system generates active current command according to frequency difference command, rotor accelerates, absorbs system surplus active;

[0101] 8) t9 to t10 stage, because rotor speed increases to the highest value, active output command is zero, so that inner rotor cannot be higher than the highest speed; frequency difference dead band f db- is set to zero in one direction, i.e. no dead band in frequency rising direction;

[0102] 9) t10 to t11 stage, grid frequency is higher than 50Hz, when grid frequency gradually recovers to 50Hz, rotor speed still keeps at the upper limit value;

[0103] 10) t11 to t12 stage, after grid frequency is lower than 50Hz, rotor sends active to grid, so that speed decreases. When rotor speed recovers to rated speed, dead band recovers to normal;

[0104] 11) t12 stage, when rotor speed recovers to reasonable range, active output command is unlocked in both directions.

[0105] The voltage and inertia support control method of the high inertia energy storage type synchronous condenser can simultaneously have the ability to suppress voltage fluctuation and provide active inertia support. The method can be applied to high inertia energy storage type synchronous condensers, synchronous condensers equipped with flywheel energy storage, or synchronous condensers with mechanical energy storage. The synchronous condenser is close to the new energy station grid connection point or connected to the grid on the same bus.

[0106] Figure 8 The structure diagram of the inertia support control system 800 of the high inertia energy storage type synchronous condenser according to the embodiment of the application is shown. As shown in Figure 8 The voltage and inertia support control system 800 of the high inertia energy storage type synchronous condenser provided by the embodiment of the application includes a judgment unit 801, an active current command value determination unit 802, and a control unit 803.

[0107] Preferably, the judgment unit 801 is configured to determine a grid frequency deviation based on a grid frequency when the grid voltage is greater than or equal to a preset voltage threshold, and determine whether the frequency deviation exceeds a dead zone range to obtain a judgment result.

[0108] Preferably, the active current command value determination unit 802 is configured to, when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation function is put into operation, generate an active current command value according to the frequency deviation, and control the grid frequency based on the active current command value.

[0109] Preferably, the active current command value determination unit 802 generates an active current command value according to the frequency deviation, including:

[0110] Entering the inertia support mode, generating a first active current command value according to the frequency deviation, including:

[0111]

[0112] Entering the primary frequency modulation mode, generating a second active current command value according to the frequency deviation, including:

[0113]

[0114] determining the active current command value according to the sum of the first active current command value and the second active current command value;

[0115] wherein P1 is the active power command value generated by the inertia support mode; f is the actual grid frequency; f n is the rated frequency of the grid; K i is the inertia support mode coefficient; T iis the time constant of the inertia support mode; s is the Laplace operator; f and f n is the frequency deviation; P2 is the active power command value generated by the primary frequency modulation mode; K p is the primary frequency modulation mode coefficient; T p is the primary frequency modulation mode coefficient.

[0116] Preferably, the control unit 803 is configured to acquire the rotor speed in real time, set the active output command to zero and adjust the dead zone range when the rotor speed reaches the rotor speed limit value, and restore the dead zone range to normal and unlock the active output command when the rotor speed returns to the preset range.

[0117] Preferably, the control unit 803, when the rotor speed reaches the rotor speed limit value, sets the active output command to zero and adjusts the dead zone range, and when the rotor speed returns to the preset range, restores the dead zone range to normal, comprising:

[0118] When the rotor speed decreases to the minimum rotor speed, the active output command is set to zero, and the frequency difference dead zone f db+ is set to zero in a single direction, until the grid frequency is greater than 50 Hz, the rotor absorbs active power from the grid to increase the speed, and when the rotor speed returns to the rated speed, the dead zone returns to normal;

[0119] When the rotor speed increases to the maximum rotor speed, the active output command is set to zero, and the frequency difference dead zone f db- is set to zero in a single direction, until the grid frequency is less than 50 Hz, the rotor sends active power to the grid to reduce the speed, and when the rotor speed returns to the rated speed, the dead zone returns to normal.

[0120] Preferably, the minimum rotor speed = rated speed of the phase modifier x (1-| minimum slip rate |); the maximum rotor speed = rated speed of the phase modifier x (1+ maximum slip rate).

[0121] Preferably, the system further comprises:

[0122] a voltage control unit configured to perform constant voltage control to obtain a reactive current command value when the grid voltage is greater than or equal to a preset voltage threshold;

[0123] a converter control unit configured to generate a modulation wave based on the reactive current command value and the unlocked active current output command, to change the supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, to send reactive power or absorb and release active power during grid failure, and to realize dual support of voltage and inertia.

[0124] The inertia support control system 800 of the high inertia energy storage type synchronous condenser of the embodiment of the present application corresponds to the inertia support control method 100 of the high inertia energy storage type synchronous condenser of another embodiment of the present application, which will not be described here again.

[0125] Based on another aspect of the present application, the present application provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of any one of the inertia support control methods of the high inertia energy storage type synchronous condenser.

[0126] Based on another aspect of the present application, the present application provides an electronic device comprising:

[0127] The computer readable storage medium described above; and

[0128] One or more processors for executing the program in the computer readable storage medium.

[0129] The present application has been described by reference to a few embodiments. However, as understood by those skilled in the art, other embodiments, which are equivalent in nature to the above disclosed embodiments, are within the scope of the present application, as defined in the appended claims.

[0130] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a" or "an" means "at least one" unless otherwise clearly indicated by the context of the disclosure. The steps of any methods disclosed herein need not be performed in the exact order disclosed, unless explicitly stated.

[0131] Those skilled in the art will appreciate that embodiments of the present application can be devised for a method, a system, or a computer program product. Accordingly, the present application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0132] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0133] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0134] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0135] Finally, it should be noted that the above-mentioned embodiments are merely used to illustrate the technical solutions of the present application, rather than limit the technical solutions of the present application. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced, and any modification or replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. An inertia support control method of a high inertia energy storage type synchronous condenser, characterized by, The method comprises: When the grid voltage is greater than or equal to a preset voltage threshold, a grid frequency deviation is determined based on the grid frequency, and it is judged whether the frequency deviation exceeds a dead zone range, to obtain a judgment result; When the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation functions are put into operation, an active current instruction value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current instruction value; The rotor speed is acquired in real time, when the rotor speed reaches a rotor speed limit value, the active output instruction is set to zero and the dead zone range is adjusted, until the rotor speed returns to a preset range, the dead zone range is restored to normal, and the active output instruction is unlocked; The control unit, when the rotor speed reaches the rotor speed limit value, sets the active output instruction to zero and adjusts the dead zone range, until the rotor speed returns to the preset range, restores the dead zone range to normal, and includes: When the rotor speed drops to the minimum speed, the active output command is set to zero, and the frequency difference dead zone One-way zeroing, until the grid frequency is greater than 50 Hz, the rotor absorbs active power from the grid, the speed rises, and when the rotor speed returns to the rated speed, the dead zone returns to normal; When the rotor speed rises to the maximum speed, the active output instruction is set to zero, and the frequency difference dead zone One-way zero, until the grid frequency is less than 50Hz, the rotor sends active to the grid, the speed is reduced, and when the rotor speed returns to the rated speed, the dead zone returns to normal.

2. The method of claim 1, wherein, The active current instruction value determination unit generates the active current instruction value according to the frequency deviation, including: Entering the inertia support mode, generating a first active current instruction value according to the frequency deviation, including: ， Entering the primary frequency modulation mode, generating a second active current instruction value according to the frequency deviation, including: ， Determining the active current instruction value according to the sum of the first active current instruction value and the second active current instruction value; wherein, is an active power command value generated by the inertia support mode; is the grid actual frequency; is the grid rated frequency; is an inertia support mode coefficient; is an inertia support mode time constant; is a Laplace operator; is a difference of the frequency deviation; is an active power command value generated by the primary frequency regulation mode; is a primary frequency regulation mode coefficient; is a primary frequency regulation mode coefficient.

3. The method of claim 1, wherein, The minimum speed = rated speed of the phase modifier × (1-| minimum slip |); the maximum speed = rated speed of the phase modifier × (1+ maximum slip).

4. The method of claim 1, wherein, The method further comprises: When the grid voltage is greater than or equal to a preset voltage threshold, a grid frequency deviation is determined based on the grid frequency, and it is judged whether the frequency deviation exceeds a dead zone range, to obtain a judgment result; Based on the reactive current instruction value and the unlocked active current output instruction, a modulation wave is generated to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase modifier, and to emit reactive power or absorb and release active power during grid failure, realizing double support of voltage / inertia.

5. A voltage and inertia support control system for a high-inertia stored-energy synchronous condenser, characterized by, The system comprises: A judgment unit is configured to, when the grid voltage is greater than or equal to a preset voltage threshold, determine a grid frequency deviation based on the grid frequency, and judge whether the frequency deviation exceeds a dead zone range, to obtain a judgment result; An active current instruction value determination unit is configured to, when the judgment result indicates that the frequency deviation exceeds the dead zone range, the system frequency is disturbed, the inertia support and primary frequency modulation functions are put into operation, an active current instruction value is generated according to the frequency deviation, and the grid frequency is controlled based on the active current instruction value; A control unit is configured to acquire the rotor speed in real time, when the rotor speed reaches a rotor speed limit value, the active output instruction is set to zero and the dead zone range is adjusted, until the rotor speed returns to a preset range, the dead zone range is restored to normal, and the active output instruction is unlocked; The control unit, when the rotor speed reaches the rotor speed limit value, sets the active output instruction to zero and adjusts the dead zone range, until the rotor speed returns to the preset range, restores the dead zone range to normal, and includes: When the rotor speed drops to the minimum speed, the active output command is set to zero, and the frequency difference dead zone One-way zeroing, until the grid frequency is greater than 50 Hz, the rotor absorbs active power from the grid, the speed rises, and when the rotor speed returns to the rated speed, the dead zone returns to normal; When the rotor speed rises to the maximum speed, the active output instruction is set to zero, and the frequency difference dead zone One-way zero, until the grid frequency is less than 50Hz, the rotor sends active to the grid to reduce the speed, and when the rotor speed returns to the rated speed, the dead zone returns to normal.

6. The system of claim 5, wherein, The active current instruction value determination unit generates the active current instruction value according to the frequency deviation, including: Entering the inertia support mode, generating a first active current instruction value according to the frequency deviation, including: Entering the primary frequency modulation mode, generating a second active current instruction value according to the frequency deviation, including: Determining the active current instruction value according to the sum of the first active current instruction value and the second active current instruction value; ， Enter a frequency modulation mode once in a line, generating a second active current instruction value according to the frequency deviation, comprising: ， Determining an active current instruction value according to the sum of the first active current instruction value and the second active current instruction value; wherein, is an active power command value generated by the inertia support mode; is the grid actual frequency; is the grid rated frequency; is an inertia support mode coefficient; is an inertia support mode time constant; is the Laplace operator; is the difference of the two values of the frequency deviation; is an active power command value generated by the primary frequency regulation mode; is a primary frequency regulation mode coefficient; is a primary frequency regulation mode coefficient.

7. The system of claim 5, wherein, The minimum value of the rotating speed = rated rotating speed of the phase modifier × (1- |minimum value of the rotating speed slip|); The maximum value of the rotating speed = rated rotating speed of the phase modifier × (1+ maximum value of the rotating speed slip).

8. The system of claim 5, wherein, The system further comprises: A voltage control unit for performing constant voltage control to obtain a reactive current instruction value when the grid voltage is greater than or equal to a preset voltage threshold; A converter control unit for generating a modulation wave based on the reactive current instruction value and the active current output instruction after unlocking, so as to change the power supply frequency of the converter to control the operating state of the phase modifier, and emit reactive power or absorb and release active power during grid failure, thereby achieving double support of voltage / inertia.

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