Inertia support control method and system for high-inertia energy storage type synchronous phase modifier

Abstract

The invention discloses an inertia support control method and system for a high-inertia energy storage type synchronous phase modifier, and the method comprises the steps: determining the frequency deviation of a power grid based on the frequency of the power grid when the voltage of the power grid is greater than or equal to a preset voltage threshold value, judging whether the frequency deviation exceeds a dead zone range or not, and obtaining a judgment result; when the judgment result indicates that the frequency deviation exceeds a dead zone range, disturbance, inertia support and primary frequency modulation function input of the system frequency occur, an active current instruction value is generated according to the frequency deviation, and the power 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 be zero, the dead zone range is adjusted till the rotor speed is recovered to the preset range, the dead zone range is recovered to be normal, and the active output instruction is unlocked.

Description

Technical Field

[0001] The present invention relates to the field of motor and electrical appliance and power electronic control technology, and more specifically, to an inertia support control method and system for a high-inertia energy storage type synchronous condenser. Background Art

[0002] With the continuous increase in the proportion of new energy in new power systems, the voltage and inertia support capacity of the power supply side is decreasing, and synchronous condensers have become key equipment to ensure the sustainable development of new energy. Synchronous condensers can be divided into large-capacity centralized and small-capacity distributed. Large-capacity centralized condensers are usually configured in DC receiving converter stations to improve the voltage stability of the system, while small-capacity and distributed condensers can be configured in new energy stations, which can not only play the role of dynamic reactive power reserve of the system, but also provide sub-transient, transient and steady-state voltage support for the whole process for new energy power stations.

[0003] Synchronous condensers have inertial response characteristics, that is, the rotor has rotational inertia and the rotor winding flux is conserved. When the system is disturbed, the magnitude and phase of the equivalent potential of the synchronous condenser do not change suddenly, showing the characteristics of a voltage source. Distributed condensers are usually connected to the grid at a relatively close electrical distance from the new energy station. This characteristic determines that the synchronous condenser will bear the active power disturbance in the transient process of the system together with the synchronous generator. While the synchronous condenser provides a certain inertia support for system failures, it may also cause the condenser itself to be at risk of power angle instability due to the continuous excess or shortage of active power in 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 serious with the rapid development of new energy installations in the next five years. The national standard "Guidelines for Safety and Stability of Power Systems" stipulates that in areas with a high proportion of new energy, new energy stations should provide voltage support and a certain amount of inertia support to the system. 21 distributed phase regulators have been put into operation in the concentrated new energy transmission area of ​​Qinghai Power Grid, and multiple phase regulators have been put into operation in the northern Hebei Power Grid. Synchronous phase regulators have become the main means to solve overvoltage and low voltage problems in some areas.

[0005] At present, the synchronous condensers connected to the grid mainly solve the problem of voltage stability. No synchronous condenser has the ability of active inertia support and primary frequency regulation, and there is no clear method for inertia support and primary frequency regulation of synchronous condensers. The logic and criteria for variable speed operation of the synchronous condenser rotor have not been proposed.

[0006] Therefore, an inertia support control method for a high inertia energy storage type synchronous condenser is needed. Summary of the invention

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

[0008] In order to solve the above problem, according to one aspect of the present invention, an inertia support control method of a high inertia energy storage type synchronous condenser is provided, the method comprising:

[0009] 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 determining whether the frequency deviation exceeds a dead zone range, and obtaining a determination result;

[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 regulation functions are put into use, 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;

[0011] The rotor speed is obtained in real time. When the rotor speed reaches the rotor speed limit, the active output command is set to zero and the dead zone range is adjusted. When 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, generating an active current command value according to the frequency deviation comprises:

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

[0014]

[0015] Entering the primary frequency modulation mode and generating a second active current command value according to the frequency deviation includes:

[0016]

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

[0018] Among them, P1 is the active power command 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 time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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, the active output instruction is set to zero and the dead zone range is adjusted until the rotor speed returns to a preset range, and the dead zone range is restored to normal, including:

[0020] When the rotor speed drops to the minimum speed, the active output command is set to zero and the frequency difference dead zone f db+ The single direction is set to zero until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, causing the speed to increase, 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 speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

[0022] Preferably, the minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

[0023] Preferably, the method further comprises:

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

[0025] A modulation wave is generated based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during power grid faults, and realize dual support of voltage / inertia.

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

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

[0028] An active current command value determination unit is used 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 regulation functions are put into use, 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;

[0029] The control unit is used to obtain the rotor speed in real time. When the rotor speed reaches the rotor speed limit, 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.

[0030] Preferably, the active current command value determining unit generates the active current command value according to the frequency deviation, comprising:

[0031] Enter the inertia support mode and generate the first active current command value according to the frequency deviation, including:

[0032]

[0033] Entering the primary frequency modulation mode and generating a second active current command value according to the frequency deviation includes:

[0034]

[0035] Determining an active current command value according to the sum of the first active current command value and the second active current command value;

[0036] Among them, P1 is the active power command 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 time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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.

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

[0038] When the rotor speed drops to the minimum speed, the active output command is set to zero and the frequency difference dead zone f db+ The single direction is set to zero until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, causing the speed to increase, 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 speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

[0040] Preferably, the minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

[0041] Preferably, the system further comprises:

[0042] A voltage control unit, used 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;

[0043] The converter control unit is used to generate a modulation wave based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during a power grid fault, and realize dual support of voltage / inertia.

[0044] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any step of an inertia support control method for a high-inertia energy storage type synchronous condenser.

[0045] According to another aspect of the present invention, the present invention provides an electronic device, including:

[0046] The computer-readable storage medium described above; and

[0047] One or more processors are used to execute the program in the computer-readable storage medium.

[0048] The present invention provides an inertia support control method and system for a high-inertia energy storage type synchronous condenser, comprising: when a grid voltage is greater than or equal to a preset voltage threshold, determining a grid frequency deviation based on the grid frequency, 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, a disturbance occurs in the system frequency, inertia support and primary frequency regulation functions are put into operation, 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; the rotor speed is obtained in real time, and when the rotor speed reaches the rotor speed limit, 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. The high-inertia energy storage synchronous phase regulator of the present invention can provide active inertia support capabilities, and can absorb or release kinetic energy stored in the rotor to the power grid through rotor speed change, thereby reducing the risk of transient power angle instability of the phase regulator, improving the stable operation level of the power grid, and improving the level of new energy consumption and utilization; it provides a new implementation method for new energy stations to simultaneously meet voltage and inertia support requirements, solves the problem that new energy stations need to be equipped with multiple sets of equipment, and reduces investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0050] Figure 1 It is a flow chart of an inertia support control method 100 of a high inertia energy storage type synchronous condenser according to an embodiment of the present invention;

[0051] Figure 2 A circuit diagram of a high inertia energy storage type synchronous condenser according to an embodiment of the present invention;

[0052] Figure 3 A schematic structural diagram of a high inertia energy storage type synchronous condenser according to an embodiment of the present invention;

[0053] Figure 4 It is a structural schematic diagram of generating active current instructions based on inertia support and primary frequency modulation according to an embodiment of the present invention;

[0054] Figure 5 A schematic diagram of a structure for generating a reactive current command by a voltage / reactive power control method according to an embodiment of the present invention;

[0055] Figure 6 A flowchart of voltage and inertia support control of a high inertia energy storage type synchronous condenser according to an embodiment of the present invention;

[0056] Figure 7 A schematic diagram of the change of the operating state of a high inertia energy storage type synchronous condenser according to an embodiment of the present invention;

[0057] Figure 8 Schematic diagram of the structure of an inertia support control system 800 of a high-inertia energy storage type synchronous condenser according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0059] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0060] Figure 1 Flow chart of the inertia support control method 100 of the high inertia energy storage type synchronous condenser according to an embodiment of the present invention. Figure 1 As shown, the inertia support control method of the high-inertia energy storage type synchronous condenser provided in the embodiment of the present invention can provide the ability of active inertia support, and can absorb or release the kinetic energy stored in the rotor to the power grid through the rotor speed change operation, thereby reducing the risk of transient power angle instability of the condenser, improving the stable operation level of the power grid, and improving the level of new energy consumption and utilization; it provides a new implementation method for new energy stations to meet the requirements of voltage and inertia support at the same time, solves the problem that new energy stations need to be equipped with multiple sets of equipment, and reduces investment costs. The inertia support control method 100 of the high-inertia energy storage type synchronous condenser provided in the embodiment of the present invention starts from step 101. In step 101, 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 it is determined whether the frequency deviation exceeds the dead zone range to obtain the judgment 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 put into use, 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 an active current command value according to the frequency deviation comprises:

[0063] Enter the inertia support mode and generate the first active current command value according to the frequency deviation, including:

[0064]

[0065] Entering the primary frequency modulation mode and generating a second active current command value according to the frequency deviation includes:

[0066]

[0067] Determining an active current command value according to the sum of the first active current command value and the second active current command value;

[0068] Among them, P1 is the active power command 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 time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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.

[0069] In the present invention, the motor part of the high-inertia energy storage type synchronous condenser is a traditional synchronous motor, and the converter part is composed of a back-to-back grid-side inverter and a machine-side inverter. The inverters on both sides have the ability to flow active power in both directions, and the grid frequency and phase angle are obtained through the phase-locked loop module; the rotor speed can be changed to absorb or release a certain amount of active power in a short time to achieve inertia and primary frequency modulation support. The initial operating state of the condenser can be set, such as delayed phase reactive power, advanced phase reactive power, slip rate, inertia and primary frequency modulation dead zone; the control mode of the condenser can be set, such as constant voltage control and constant reactive power control.

[0070] The high inertia energy storage synchronous condenser converter control system consists of two feedback loops: the external power loop and the internal current loop. The overall block diagram is as follows: Figure 2 As shown in Figure 1, the generation of active current command value includes inertia support working mode and primary frequency modulation working mode, and the generation of reactive command includes constant reactive power control mode and constant voltage control mode. The structure of high inertia energy storage synchronous condenser converter control system is shown in Figure 1. Figure 3 shown.

[0071] In the present invention, the frequency dead zone [f db- ,f db+], the grid frequency can be calculated through the phase-locked loop. The grid frequency deviation fluctuates within the frequency dead zone, and the phase-converter rotor speed does not change; when the grid frequency deviation exceeds the set frequency dead zone, the inertia and primary frequency regulation functions are activated, and active power commands are issued or absorbed; when the grid frequency returns to the dead zone, the active power command is locked.

[0072] According to the design scheme of high inertia energy storage type synchronous condenser motor, the rated speed and maximum slip rate of the synchronous motor can be obtained. The minimum speed value = rated speed of the condenser × (1-|minimum slip rate|); the maximum speed value = rated speed of the condenser × (1+maximum slip rate). For example, the rated speed of the high inertia energy storage type synchronous condenser is 3000r / min, and the maximum slip rate is [-0.12,0.15]. The maximum speed change range is [2640,3450]r / min. The rotor speed can run stably within this range. After reaching the limit value, the active power command is set to zero.

[0073] Combination Figure 4 As shown, in the present invention, for the inertia support mode, when the system frequency is disturbed, the phase regulator provides a certain inertia support for the power grid. A virtual inertia support link is added to the control system. When the system frequency is disturbed, the control system generates a reference value of the phase regulator active power based on the rate of change of the power grid frequency, and then generates an active current command through a proportional-integral link, so that the rotor speed is additionally increased or decreased, absorbing or releasing more active power, and realizing additional inertia support. The first active current command value generated at this time is:

[0074]

[0075]

[0076] Wherein, P1 is the active power command value generated by the inertia support mode; T jv is the virtual inertia time constant of high inertia energy storage synchronous condenser; 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.

[0077] In the present invention, the primary frequency modulation mode works during the frequency disturbance process. When the system frequency deviation exceeds the frequency dead zone, the rotor speed changes, absorbing or releasing active power, and the generated active power reference value is proportional to the frequency difference deviation. The generated second active current command value is:

[0078]

[0079] Where P2 is the active power command value generated by the primary frequency modulation mode; f is the actual frequency of the power grid; f n is the rated frequency of the power grid; K p is the primary frequency modulation mode coefficient; T p is the coefficient of the primary frequency modulation mode; 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, the active output command is set to zero and the dead zone range is adjusted. When 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, when the rotor speed reaches the rotor speed limit, the active output instruction is set to zero and the dead zone range is adjusted until the rotor speed returns to a preset range, and the dead zone range is restored to normal, including:

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

[0083] When the rotor speed increases to the maximum speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

[0084] Preferably, the minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

[0085] In the present invention, after 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 instruction is set to zero so that the inner rotor speed shall not be lower than the minimum speed. The frequency difference dead zone f db+ Zero is set in one direction, that is, 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 to increase the speed; 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 increases to absorb active power. When the rotor speed increases to the maximum value, the active output command is set to zero, so that the inner rotor speed does not exceed the maximum speed. db-Zeroing in one direction means there is no dead zone in the frequency reduction direction. When the grid frequency is lower than 50Hz, the rotor sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

[0087] Eventually, the rotor speed returns to a reasonable range, and active power output commands are unlocked in both directions.

[0088] Preferably, the method further comprises:

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

[0090] A modulation wave is generated based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during power grid faults, and realize dual support of voltage / inertia.

[0091] Combination Figure 5 As shown, in the present invention, the voltage / reactive power control mode of the high-inertia energy storage type synchronous phase regulator can be divided into constant voltage control and constant reactive power control. Constant voltage control refers to generating a reactive current command reference value based on the deviation value between the reference value of the voltage bus of the controlled power grid and the actual voltage of the power grid. Constant reactive power control means that when the phase regulator is connected to the grid, the host computer issues a reactive command. According to the needs of the power grid, the phase regulator can be operated in three states: zero reactive, leading phase and lagging phase. After receiving the command of the dispatching system, the reactive current can be increased or decreased, and the emitted reactive value can be changed. Constant reactive power control or constant voltage control can be performed in steady state, and voltage control can be performed in fault conditions.

[0092] The high inertia energy storage type synchronous condenser of the present invention can realize voltage and inertia support control at the same time. The logic judgment process is as follows: Figure 6 When the grid voltage is less than 0.8pu, the active current is locked, and reactive current is generated only based on voltage control; when the grid voltage is less than or equal to 0.8pu, active current and reactive current can be generated simultaneously, wherein active current is generated based on the grid frequency, and finally a modulation wave is generated according to the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during grid faults, and realize dual support of voltage / inertia.

[0093] In the embodiment of the present invention, in actual operation, the operating data between the grid frequency, the output active power of the high inertia energy storage type synchronous condenser and the rotor speed are as follows: Figure 7 As shown. Combined with the power grid operating conditions, the following operating states can be obtained:

[0094] 1) From the beginning to stage t1, the grid frequency fluctuates within the dead zone, and the converter has no active output;

[0095] 2) During the period from t1 to t2, the grid frequency is lower than 50Hz. When the difference between the grid frequency and the given value exceeds f db- After that, the inertia control takes effect, and the control system generates an active current command according to the frequency difference command, the rotor slows down, and outputs active power to the system;

[0096] 3) During the period from t2 to t3, since the rotor speed is reduced to the minimum value, the active output command is set to zero, so that the inner rotor speed shall not be lower than the minimum speed; the frequency difference dead zone f db+ Zero setting in one direction means there is no dead zone in the direction of frequency increase;

[0097] 4) From t3 to t4, the grid frequency is lower than 50Hz. When the grid frequency gradually recovers to 50Hz, the rotor speed remains at the lower limit;

[0098] 5) From t4 to t5, when the grid frequency is higher than 50Hz, the rotor absorbs active power from the grid, increasing the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal;

[0099] 6) From t5 to t8, the grid frequency fluctuates within the dead zone, and the converter has no active output;

[0100] 7) During the period from t8 to t9, the grid frequency is higher than 50Hz. When the difference between the grid frequency and the given value exceeds f db+ After that, the inertia control takes effect, and the control system generates an active current command according to the frequency difference command, the rotor accelerates, and the surplus active power of the system is absorbed;

[0101] 8) During the period from t9 to t10, as the rotor speed increases to the maximum value, the active output command is set to zero, so that the inner rotor speed does not exceed the maximum speed; the frequency difference dead zone f db- Zero setting in one direction means there is no dead zone in the direction of frequency increase;

[0102] 9) During the period from t10 to t11, the grid frequency is higher than 50 Hz. When the grid frequency gradually recovers to 50 Hz, the rotor speed remains at the upper limit;

[0103] 10) During the period from t11 to t12, when the grid frequency is lower than 50Hz, the rotor sends active power to the grid, reducing the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal;

[0104] 11) After t12, when the rotor speed returns to a reasonable range, the active power output command is unlocked in both directions.

[0105] The voltage and inertia support control method of the high inertia energy storage type synchronous condenser of the present invention can enable the high inertia energy storage type synchronous condenser to have the ability to suppress voltage fluctuations and provide active inertia support at the same time. The method of the present invention 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 electrically close to the grid connection point of the new energy station or is connected to the grid through the same bus.

[0106] Figure 8 Schematic diagram of the structure of the inertia support control system 800 of the high inertia energy storage type synchronous condenser according to an embodiment of the present invention. Figure 8 As shown, the voltage and inertia support control system 800 of the high inertia energy storage type synchronous condenser provided in the embodiment of the present invention 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 used to determine the grid frequency deviation based on the grid frequency when the grid voltage is greater than or equal to a preset voltage threshold, and to judge 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 used to generate an active current command value according to the frequency deviation 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 put into use, and the grid frequency is controlled based on the active current command value.

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

[0110] Enter the inertia support mode and generate the first active current command value according to the frequency deviation, including:

[0111]

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

[0113]

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

[0115] Among them, P1 is the active power command 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 iis the time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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 used to obtain the rotor speed in real time. When the rotor speed reaches the rotor speed limit, 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.

[0117] Preferably, the control unit 803, when the rotor speed reaches the rotor speed limit, sets the active output instruction to zero and adjusts the dead zone range until the rotor speed returns to a preset range, and then restores the dead zone range to normal, including:

[0118] When the rotor speed drops to the minimum speed, the active output command is set to zero and the frequency difference dead zone f db+ The single direction is set to zero until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, causing the speed to increase, 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 speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

[0120] Preferably, the minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

[0121] Preferably, the system further comprises:

[0122] A voltage control unit, used 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] The converter control unit is used to generate a modulation wave based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during a power grid fault, and realize dual support of voltage / inertia.

[0124] The inertia support control system 800 of a high-inertia energy storage type synchronous condenser according to an embodiment of the present invention corresponds to the inertia support control method 100 of a high-inertia energy storage type synchronous condenser according to another embodiment of the present invention, and will not be described in detail herein.

[0125] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any step of an inertia support control method for a high-inertia energy storage type synchronous condenser.

[0126] According to another aspect of the present invention, the present invention provides an electronic device, including:

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

[0128] One or more processors are used to execute the program in the computer-readable storage medium.

[0129] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent 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 therein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of said means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0131] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0133] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the inertia support of a high inertia energy storage type synchronous condenser, characterized in that: The method comprises: 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 determining whether the frequency deviation exceeds a dead zone range, and obtaining a determination 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 regulation functions are put into use, 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; The rotor speed is obtained in real time. When the rotor speed reaches the rotor speed limit, the active output command is set to zero and the dead zone range is adjusted. When the rotor speed returns to the preset range, the dead zone range is restored to normal and the active output command is unlocked.

2. The method according to claim 1, characterized in that Generating an active current command value according to the frequency deviation includes: Enter the inertia support mode and generate the first active current command value according to the frequency deviation, including: Entering the primary frequency modulation mode and generating a second active current command value according to the frequency deviation includes: Determining an active current command value according to the sum of the first active current command value and the second active current command value; Among them, P1 is the active power command 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 time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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.

3. The method according to claim 1, characterized in that When the rotor speed reaches the rotor speed limit, the active output command is set to zero and the dead zone range is adjusted until the rotor speed returns to a preset range, and the dead zone range is restored to normal, including: When the rotor speed drops to the minimum speed, the active output command is set to zero and the frequency difference dead zone f db+ The single direction is set to zero until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, causing the speed to increase, and when the rotor speed returns to the rated speed, the dead zone returns to normal; When the rotor speed increases to the maximum speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

4. The method according to claim 3, characterized in that The minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

5. The method according to claim 1, characterized in that The method further comprises: When the grid voltage is greater than or equal to the preset voltage threshold, constant voltage control is performed to obtain a reactive current command value; A modulation wave is generated based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during power grid faults, and realize dual support of voltage / inertia.

6. A voltage and inertia support control system for a high inertia energy storage type synchronous condenser, characterized in that: The system comprises: A judgment unit, configured to determine a grid frequency deviation based on the grid frequency when the grid voltage is greater than or equal to a preset voltage threshold, and to judge whether the frequency deviation exceeds a dead zone range, and obtain a judgment result; An active current command value determination unit is used 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 regulation functions are put into use, 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; The control unit is used to obtain the rotor speed in real time. When the rotor speed reaches the rotor speed limit, 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.

7. The system according to claim 6, characterized in that The active current command value determining unit generates the active current command value according to the frequency deviation, including: Enter the inertia support mode and generate the first active current command value according to the frequency deviation, including: Entering the primary frequency modulation mode and generating a second active current command value according to the frequency deviation includes: Determining an active current command value according to the sum of the first active current command value and the second active current command value; Among them, P1 is the active power command 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 time constant of the inertial support mode; s is the Laplace operator; f and f n The difference 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.

8. The system according to claim 6, characterized in that The control unit, when the rotor speed reaches the rotor speed limit, sets the active output instruction to zero and adjusts the dead zone range until the rotor speed returns to a preset range, and then restores the dead zone range to normal, including: When the rotor speed drops to the minimum speed, the active output command is set to zero and the frequency difference dead zone f db+ The single direction is set to zero until the grid frequency is greater than 50Hz, the rotor absorbs active power from the grid, causing the speed to increase, and when the rotor speed returns to the rated speed, the dead zone returns to normal; When the rotor speed increases to the maximum speed, the active output command is set to zero and the frequency difference dead zone f db- It is set to zero in one direction until the grid frequency is less than 50Hz. The rotor then sends active power to the grid to reduce the speed. When the rotor speed returns to the rated speed, the dead zone returns to normal.

9. The system according to claim 8, characterized in that The minimum speed=rated speed of the phase regulator×(1-|minimum slip|); the maximum speed=rated speed of the phase regulator×(1+maximum slip).

10. The system according to claim 6, characterized in that The system further comprises: A voltage control unit, used 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; The converter control unit is used to generate a modulation wave based on the reactive current command value and the unlocked active current output command, so as to change the power supply frequency of the converter based on the modulation wave to control the operating state of the phase regulator, emit reactive power or absorb and release active power during a power grid fault, and realize dual support of voltage / inertia.

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