Network-constructed energy storage power angle stability control method and system in new energy sending system

Abstract

The application discloses a network-constructed energy storage power angle stability improvement method and system in a new energy external transmission system, and comprises the following steps: obtaining inherent parameters of the new energy external transmission system, and determining parameters of a double PI control link; calculating a rotor relative angle of the new energy external transmission system in real time based on the inherent parameters; when the rotor relative angle is not in a preset rotor relative angle range interval, calculating an angle deviation amount; calculating an angular velocity deviation amount through the double PI control link based on the angular velocity deviation amount; updating the rotor angular velocity based on the angular velocity deviation amount, dynamically adjusting an angular velocity of network-constructed energy storage in the new energy external transmission system, and improving power angle stability of the network-constructed energy storage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, and more particularly, to a grid-connection type energy storage power angle stability control method and system in a new energy transmission system. BACKGROUND

[0002] In the process of actively and prudently promoting carbon peak and carbon neutrality, building a high-proportion new energy system is becoming the main trend of the development of new-type power systems. However, as the installed capacity of new energy increases, the sending-end power grid locally exhibits low short-circuit ratio and weak grid characteristics, and large-scale new energy bases are prone to voltage out-of-limit and wide-band oscillation problems when transmitted over a long distance, which seriously affects the safe and stable operation of the power system.

[0003] In a new energy transmission system, supporting energy storage devices can comprehensively improve the reliability and stability of the new energy power system. The energy storage system is mostly connected to the grid using a grid-connection type method, which presents a current source characteristic to the grid and can achieve independent decoupling control of active power and reactive power, with fast power response speed. However, the stability of its control is heavily dependent on the stability and performance of the grid-connection phase-locked loop (PLL), and when the sending-end power grid system is weak, oscillation or even instability may occur. In particular, during system disturbances, the grid-connection type converter passively responds to the system's demand, and its support for system voltage and frequency is limited.

[0004] By adding virtual synchronous generator control to the control strategy of the grid-connection voltage source converter, the voltage source characteristic of a synchronous machine can be simulated, thereby improving the system's active support capability. Electrochemical energy storage based on grid-connection type converters changes the power by controlling the amplitude and phase angle of the internal potential, and as a whole, presents a voltage source characteristic, which can approximately simulate the characteristics of a conventional synchronous generator, while also needing to have certain capabilities to meet the needs of parallel operation of multiple voltage sources.

[0005] Grid-connection type energy storage technology adjusts output power flexibly by controlling the amplitude and phase of the equivalent internal potential, and presents a voltage source characteristic to the outside, which can provide voltage source support characteristics for the AC power grid. Typically, grid-connection type energy storage converters use virtual synchronous machine control strategies, which have the ability to improve weak grid voltage support. Moreover, they have the characteristics of flexible and fast adjustment in control strategies, which is a significant advantage compared to phase modulators. In addition, phase modulators are rotating devices with high maintenance costs, while grid-connection type energy storage is easy to maintain and repair. However, similar to phase modulators, grid-connection type energy storage also has transient power angle stability problems when connected to large-scale new energy bases.

[0006] Grid-forming energy storage can simulate the external characteristics of a phase modifier, and the adjustment characteristics are more convenient and flexible, so grid-forming energy storage can be connected to the power system instead of a phase modifier, but there may be a transient power angle instability problem under fault, which has not attracted the attention of the industry, and there is little related research. Therefore, it is necessary to study the synchronous instability mechanism and transient power angle stability of grid-forming energy storage connected to a new energy station. SUMMARY

[0007] The application provides a grid-forming energy storage power angle stability control method and system in a new energy sending system, to solve the problem of how to improve the power angle stability of grid-forming energy storage in a new energy sending system.

[0008] In order to solve the above problems, according to one aspect of the application, a grid-forming energy storage power angle stability control method in a new energy sending system is provided, the method comprising:

[0009] acquiring inherent parameters of the new energy sending system, and determining parameters of a double PI control link;

[0010] calculating a rotor relative angle of the new energy sending system in real time based on the inherent parameters;

[0011] calculating an angle deviation amount when the rotor relative angle is not within a preset rotor relative angle range interval;

[0012] calculating an angular velocity deviation amount through the double PI control link based on the angle velocity deviation amount;

[0013] updating the rotor angular velocity based on the angular velocity deviation amount, dynamically adjusting the angular velocity of the grid-forming energy storage in the new energy sending system, and improving the power angle stability of the grid-forming energy storage.

[0014] Preferably, the new energy sending system comprises at least one new energy device and one grid-forming energy storage device, all devices are connected to the power grid through a common PCC, are dispersedly distributed in the system, and can respond to local power grid frequency and voltage fluctuations.

[0015] Preferably, the calculation of the rotor relative angle of the new energy sending system in real time based on the inherent parameters comprises:

[0016]

[0017] wherein, δ is the rotor relative angle; J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronous machine; ω0 is the angular velocity reference value of the virtual synchronous machine; P ref is the active power command value of the grid-forming energy storage; P1 is the active power output by the grid-forming energy storage.

[0018] Preferably, the angle deviation amount is 0 when the rotor relative angle is within a preset rotor relative angle range interval.

[0019] Preferably, the method takes the rotor relative angle δ at the PCC point and the infinite grid as input, outputs the angular velocity deviation amount Δω through a double PI control link and a limiting link, and adds the angular velocity deviation amount Δω to the active link; during the fault, if δ > δ max , Δω2=0 and Δω1<0 are obtained through the double PI control link, so as to inhibit the rotor relative angle δ from continuously increasing; if δ < δ min , Δω2<0 and Δω1=0 are obtained through the double PI control link, so as to inhibit the rotor relative angle δ from continuously decreasing; Δω1 and Δω2 are the angle deviation amounts obtained through the double PI control link; δ max is the maximum value of the preset rotor relative angle range interval; and δ min is the minimum value of the preset rotor relative angle range interval.

[0020] According to another aspect of the present application, a grid-formation type energy storage power angle stability control system in a new energy sending system is provided, and the system comprises:

[0021] a parameter determination unit configured to obtain inherent parameters of the new energy sending system and determine parameters of a double PI control link;

[0022] a rotor relative angle calculation unit configured to calculate a rotor relative angle of the new energy sending system in real time based on the inherent parameters;

[0023] an angle deviation amount calculation unit configured to calculate an angle deviation amount when the rotor relative angle is not within a preset rotor relative angle range interval;

[0024] an angular velocity deviation amount calculation unit configured to calculate an angular velocity deviation amount based on the angle deviation amount through a double PI control link;

[0025] an adjustment unit configured to update a rotor angular velocity based on the angular velocity deviation amount, dynamically adjust an angular velocity of a grid-formation type energy storage in the new energy sending system, and improve the power angle stability of the grid-formation type energy storage.

[0026] Preferably, the new energy sending system comprises at least one new energy device and one grid-formation type energy storage device, all the devices are connected to the grid through a common PCC, are dispersedly distributed in the system, and can respond to fluctuations in local grid frequency and voltage.

[0027] Preferably, the rotor relative angle calculation unit calculates the rotor relative angle of the new energy sending system in real time based on the inherent parameters, and the calculation comprises:

[0028]

[0029] wherein, δ is a rotor relative angle; J is a virtual inertia coefficient; D is a virtual damping coefficient; ω is an angular velocity of a virtual synchronous machine; ω0 is an angular velocity reference value of the virtual synchronous machine; P ref is an active power instruction value of the grid-forming energy storage; P1 is an active power output by the grid-forming energy storage.

[0030] Preferably, wherein the angle deviation amount is 0 when the rotor relative angle is within a preset rotor relative angle range interval.

[0031] Preferably, wherein the system takes the rotor relative angle δ at the PCC point and the infinite grid as an input, outputs an angular velocity deviation amount Δω through a double PI control link and a limiting link, and adds the angular velocity deviation amount Δω to an active power link; wherein, during a fault, if δ> δ max , Δω2=0 and Δω1<0 are obtained through the double PI control link, so as to suppress the rotor relative angle δ from continuously increasing; if δ< δ min , Δω2<0 and Δω1=0 are obtained through the double PI control link, so as to suppress the rotor relative angle δ from continuously decreasing; Δω1 and Δω2 are respectively the angle deviation amounts obtained through the double PI control link; δ max is a maximum value of the preset rotor relative angle range interval; δ min is a minimum value of the preset rotor relative angle range interval.

[0032] The present application provides a grid-forming energy storage power angle stability control method and system in a new energy sending system, comprising: obtaining inherent parameters of the new energy sending system, and determining parameters of a double PI control link; calculating a rotor relative angle of the new energy sending system in real time based on the inherent parameters; when the rotor relative angle is not within a preset rotor relative angle range interval, calculating an angle deviation amount; calculating an angular velocity deviation amount through a double PI control link based on the angular velocity deviation amount; and updating a rotor angular velocity based on the angular velocity deviation amount, so as to dynamically adjust the angular velocity of the grid-forming energy storage in the new energy sending system and improve the power angle stability of the grid-forming energy storage. The present application effectively improves the power angle stability of the new energy sending system by modifying the virtual inertia link of the grid-forming energy storage control system, and greatly enhances the safety and stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0033] The exemplary embodiments of the present application can be more completely understood in reference to the following drawings:

[0034] Figure 1 is a flowchart of a grid-forming energy storage power angle stability control method 100 in a new energy sending system according to an embodiment of the present application;

[0035] Figure 2 A schematic diagram of a new energy sending-out system according to an embodiment of the present application;

[0036] Figure 3 A control diagram of network-constructed energy storage power angle stability control in a new energy sending-out system according to an embodiment of the present application;

[0037] Figure 4 A flow chart of network-constructed energy storage power angle stability control in a new energy sending-out system according to an embodiment of the present application;

[0038] Figure 5 An example diagram of a new energy sending-out system according to an embodiment of the present application;

[0039] Figure 6 A simulation result schematic diagram according to an embodiment of the present application;

[0040] Figure 7 A structure schematic diagram of a network-constructed energy storage power angle stability control system 700 in a new energy sending-out system according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] Reference will now be made to the exemplary embodiments of the present application with reference to the accompanying drawings, however, the present application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, provided as a thorough and complete disclosure of the present application and fully conveying the scope of the present application to those skilled in the art. The terms used in the exemplary embodiments represented in the accompanying drawings are not a limitation of the present application. In the drawings, the same elements / elements are denoted by the same reference numerals.

[0042] Unless otherwise defined, the terms used herein (including technical terms) have the meanings commonly understood by one of ordinary skill in the art. In addition, it is to be understood that the terms defined by commonly used dictionaries are to be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0043] To solve the problem of transient power angle instability caused by network-constructed energy storage in a new energy sending-out system, the present application designs a network-constructed energy storage power angle stability control method in a new energy sending-out system, based on the mathematical model of a new energy and network-constructed energy storage combined sending-out system, and the equal area rule for analyzing the transient power angle instability mechanism, a power angle deviation limiting control strategy is proposed, by adding a Δω additional link in the classical virtual synchronous machine active ring link, taking the power angle difference at the grid-connected point and the infinite grid as the dependent variable, using the limiting link of the PI module, the adaptive change of the output angular frequency change Δω during the system serious fault is ensured to improve the transient power angle stability of the network-constructed energy storage.

[0044] Figure 1 A flowchart of the method 100 for power angle stability control of grid-forming energy storage in a new energy sending system according to an embodiment of the present application is shown in FIG. 1. As shown in FIG. 1, the method for power angle stability control of grid-forming energy storage in a new energy sending system according to an embodiment of the present application effectively improves the power angle stability of the new energy sending system by modifying the virtual inertia element of the grid-forming energy storage control system, thereby greatly enhancing the safety and stability of the system. The method 100 for power angle stability control of grid-forming energy storage in a new energy sending system according to an embodiment of the present application starts from step 101, in which the inherent parameters of the new energy sending system are obtained to determine the parameters of the double-PI control element. Figure 1

[0045] Preferably, the new energy sending system comprises at least one new energy device and one grid-forming energy storage device, all of which are connected to the power grid through a common PCC, are distributed in the system, and can respond to fluctuations in local grid frequency and voltage.

[0046] In step 102, the rotor relative angle of the new energy sending system is calculated in real time based on the inherent parameters.

[0047] Preferably, the calculation of the rotor relative angle of the new energy sending system in real time based on the inherent parameters comprises:

[0048]

[0049] wherein, δ is the rotor relative angle; J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronous machine; ω0 is the angular velocity reference value of the virtual synchronous machine; P ref is the active power instruction value of the grid-forming energy storage; and P1 is the active power output by the grid-forming energy storage.

[0050] As shown in FIG. 2, in the present application, the new energy sending system comprises at least one new energy device and one grid-forming energy storage device, all of which are connected to the power grid through a common PCC, are distributed in the system, and can respond to fluctuations in local grid frequency and voltage. Figure 2 In the grid-forming control technology, the most commonly used is the virtual synchronous machine control strategy, and the swing equation of the grid-forming energy storage system using the virtual synchronous machine control strategy is:

[0051]

[0052]

[0053] wherein, J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronous machine; ω0 is the angular velocity reference value of the virtual synchronous machine; P ref ​​P1 is the active power output of the grid-forming energy storage, and δ is the rotor relative angle.

[0054] In step 103, when the rotor relative angle is not in the preset rotor relative angle range interval, the angle deviation amount is calculated.

[0055] Preferably, wherein when the rotor relative angle is in the preset rotor relative angle range interval, the angle deviation amount is 0.

[0056] In step 104, based on the angular velocity deviation amount, the angular velocity deviation amount is calculated through a double PI control link.

[0057] In step 105, the rotor angular velocity is updated based on the angular velocity deviation amount, to dynamically adjust the angular velocity of the grid-forming energy storage in the new energy sending system in real time, and improve the power angle stability of the grid-forming energy storage.

[0058] Preferably, wherein the method takes the rotor relative angle δ at the PCC point and the infinite grid as input, outputs the angular velocity deviation amount Δω through a double PI control link and a limiting link, and adds the angular velocity deviation amount Δω to the active link; wherein, during the fault, if δ> δ max , Δω2=0 and Δω1<0 are obtained through the double PI control link, so as to suppress the continuous increase of the rotor relative angle δ; if δ< δ min , Δω2<0 and Δω1=0 are obtained through the double PI control link, so as to suppress the continuous decrease of the rotor relative angle δ; Δω1 and Δω2 are the angle deviation amounts obtained through the double PI control link; δ max is the maximum value of the preset rotor relative angle range interval; δ min is the minimum value of the preset rotor relative angle range interval.

[0059] When a three-phase short-circuit fault occurs, the active power of the new energy cannot be injected into the external grid during the fault, and almost all the active power of the new energy will be injected into the grid-forming energy storage. According to the equal-area rule, the acceleration area may be greater than the deceleration area, causing the transient power angle instability of the joint sending system. The power electronic equipment has extremely fast regulation capability, and when the system fails, the millisecond-level control characteristics of the power electronic equipment will actively intervene in the dynamic process of power or current readjustment, causing significant changes in the dynamic characteristics of the power system such as frequency and voltage, and quickly realizing the function of returning the system to a stable operating state. In the face of disturbance, according to the fast and effective control mechanism of the grid-forming control system, the control strategy of the grid-forming energy storage is adjusted, so that the grid-forming energy storage meets the condition that the acceleration area is less than the maximum deceleration area, which can ensure that the system can re-establish a stable operating state in a short time, and thus improve the transient power angle stability of the system.

[0060] The control block diagram of the network configuration type energy storage power angle stability control method in the new energy sending system of the application is shown in Figure 3 In the application, the rotor relative angle δ is monitored in real time by the control system, and when the rotor relative angle δ is greater than the upper limit value δ max or less than the lower limit value δ min , the angle deviation Δδ is calculated, the angular velocity deviation Δω is obtained through the PI control module, and the angular velocity of the network configuration type energy storage is dynamically adjusted in real time based on the angular velocity deviation Δω.

[0061] The control strategy of the method of the application mainly includes:

[0062] (1) The range between the upper limit value and the lower limit value is called the dead zone, and when the rotor relative angle δ is in the dead zone, unnecessary fluctuations can be avoided to prevent the controller from being frequently adjusted.

[0063] (2) When the rotor relative angle δ exceeds the dead zone range, the double PI link can quickly adjust to maintain the frequency input within the limit value.

[0064] (3) When the rotor relative angle δ deviation decreases to a certain extent, the unbalanced power disappears, the rotor relative angle δ deviation returns to the dead zone interval, and the double PI adjustment module quickly exits, which is a zero-error adjustment process.

[0065] The control strategy of the application takes the rotor relative angle δ at the PCC point and the infinite grid as the input, adds Δω output by the double PI control link and the limiting link to the active ring, and adjusts the coefficients δ max and δ min to make the Δω additional link not work in the normal operation of the system, and if δ> δ max during the fault, Δω2=0 and Δω1<0 due to the zero hard limiting, and the effect of suppressing the continuous increase of the rotor relative angle δ is achieved. Similarly, if δ< δ min , Δω2<0 and Δω1=0, and the effect of suppressing the continuous decrease of the rotor relative angle δ is achieved, and the phenomenon of the system out of step with the grid due to the failure of the active ring synchronization is improved. If the system can maintain a stable state, dδ / dt=0 and d 2 δ / dt 2 =0 are satisfied.

[0066] The rationality of the control strategy of the application is qualitatively analyzed as follows.

[0067] (1) The case of δ min < δ < δ max is analyzed: from the control block diagram, it can be seen that the additional control link Δω does not work at this time.

[0068] (2) The case of δ> δ maxAnalyzing the situation, the first derivative of δ can be derived as follows:

[0069]

[0070] The second derivative of δ is shown in the following equation:

[0071]

[0072] In the formula: L -1 (·) denotes the inverse Laplace transform, P e1 The active variable, newly defined during the derivation process, is expressed as follows:

[0073]

[0074] If adding a double PI converter with a power angle can guarantee the existence of a steady-state equilibrium point, then the system satisfies d under any state. 2 δ / dt 2 =0, i.e., dP e1 / dt=0, and dδ / dt=0. The following discussion focuses on P. e1 Analysis shows that, according to equation (13), the system must have the following at the stable equilibrium point: δ-δ max =0. Then, during a fault, the power angle δ of the converter in the grid-type energy storage is determined by the dual-PI additional stage.

[0075]

[0076] Due to the power angle dual-PI limiting circuit, when δ>δ max When the output Δω is negative, δ decreases until it satisfies δ-δ max The constraint of the equation = 0. Similarly, it can be seen that for δ < δ min When analyzing the situation, the system operating point can also return to the stable equilibrium point.

[0077] If no fault occurs and the system operates stably, the additional Δω component will not affect the system's operating point. If a fault causes the activation of the power angle dual PI component, the system can maintain transient power angle stability during the fault period.

[0078] K p and K i The two coefficients are crucial to the dynamic performance of the entire system. The rotor motion equation of the system after the dual-PI converter is activated is:

[0079]

[0080] Due to the advantage of flexible parameter adjustment of the grid-connection type energy storage control strategy, the transient power angle instability during the fault can be improved by changing the control strategy to increase the deceleration area. In view of the power angle instability problem, a grid-connection type energy storage control strategy of power angle double PI is proposed, by setting appropriate K p and K i , after the serious fault of the power grid, the double PI link can quickly control the transient power angle of the grid-connection type energy storage device in the new energy joint sending-out system within a reasonable range, thereby improving the transient power angle stability of the system.

[0081] Combined with Figure 4 , the process of the grid-connection type energy storage power angle stability control in the new energy sending-out system of the application is as follows:

[0082] Step one: obtain the inherent parameters of the target system; calculate the parameters of the target system and set the PI parameters;

[0083] Step two: set the parameters of delta max and delta min; establish the equivalent model of the grid-connection type energy storage.

[0084] Step three: debug the system, start the equipment and run.

[0085] Step four: real-time monitor the rotor relative angle delta.

[0086] Step five: if delta is in [delta min , delta max ], the rotor angular velocity compensation amount Delta omega is 0, otherwise, the rotor angular velocity compensation amount Delta omega is calculated.

[0087] Step six: update the rotor angular velocity according to the rotor angular velocity compensation amount Delta omega, so as to dynamically adjust the angular velocity of the grid-connection type energy storage in the new energy sending-out system in real time, and improve the power angle stability of the grid-connection type energy storage.

[0088] In order to fully verify the effectiveness of the control strategy, a 10-machine 39-node system as shown in Figure 5 is built in the PSCAD simulation software, and the system uses a wind farm (represented by the letter W) plus a grid-connection type energy storage (represented by the letter B) to replace the synchronous generator on bus 38. The reference power of the system is 100 MVA, and the related parameters of the grid-connection type energy storage are the same as before.

[0089] Uncharged and discharged state: the active power of the new energy is 830 MW, and the output power of the grid-connection type energy storage is 0 MW. Charged state: the active power of the new energy is 998 MW, and the total charging power of the grid-connection type energy storage is 166 MW; discharged state: the active power of the new energy is 664 MW, and the total discharging power of the grid-connection type energy storage is 166 MW.

[0090] A three-phase short-circuit fault is set at node 29. The fault occurs at t = 3s and lasts for 0.1s. Simulations can be used to obtain waveforms before and after implementing the dual-PI power angle, as shown below. Figure 6 As shown. By Figure 6 It can be seen that after adopting the dual PI control strategy for the power angle, the range of power angle variation is within the (δmax, δmin) interval, suppressing the transient power angle instability phenomenon of the system. The above simulation results are consistent with the theoretical analysis results, verifying the adaptability of the theory to multi-machine systems.

[0091] Figure 7 This is a schematic diagram of the structure of a grid-type energy storage power angle stability control system 700 in a new energy transmission system according to an embodiment of the present invention. Figure 7 As shown, the power angle stability control system 700 for the new energy transmission system provided by the present invention includes: a parameter determination unit 701, a rotor relative angle calculation unit 702, an angle deviation calculation unit 703, an angular velocity deviation calculation unit 704, and an adjustment unit 705.

[0092] Preferably, the parameter determination unit 701 is used to obtain the inherent parameters of the new energy transmission system and determine the parameters of the dual PI control link.

[0093] Preferably, the new energy transmission system includes at least one new energy device and one grid-type energy storage device. All devices are connected to the power grid through a common PCC and are distributed in a decentralized manner in the system. All devices can respond to fluctuations in local power grid frequency and voltage.

[0094] Preferably, the rotor relative angle calculation unit 702 is used to calculate the rotor relative angle of the new energy transmission system in real time based on the inherent parameters.

[0095] Preferably, the rotor relative angle calculation unit 702 calculates the rotor relative angle of the new energy transmission system in real time based on the inherent parameters, including:

[0096]

[0097] Where δ is the rotor relative angle; J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronizer; ω0 is the reference value of the angular velocity of the virtual synchronizer; P ref P1 is the active power command value of the grid-type energy storage; P2 is the active power output of the grid-type energy storage.

[0098] Preferably, the angle deviation calculation unit 703 is used to calculate the angle deviation when the rotor relative angle is not within the preset rotor relative angle range.

[0099] Preferably, the angle deviation amount is 0 when the rotor relative angle is within a preset rotor relative angle range interval.

[0100] Preferably, the angular velocity deviation amount calculation unit 704 is configured to calculate the angular velocity deviation amount through a double PI control link based on the angular velocity deviation amount.

[0101] Preferably, the system takes the rotor relative angle δ at the PCC point and the infinite grid as input, outputs the angular velocity deviation amount Δω through a double PI control link and a limiter link, and adds the angular velocity deviation amount Δω to the active power link; wherein, during the fault, if δ> δ max , Δω2=0 and Δω1<0 are obtained through the double PI control link, so as to inhibit the rotor relative angle δ from continuously increasing; if δ< δ min , Δω2<0 and Δω1=0 are obtained through the double PI control link, so as to inhibit the rotor relative angle δ from continuously decreasing; Δω1 and Δω2 are the angle deviation amounts obtained through the double PI control link; δ max is the maximum value of the preset rotor relative angle range interval; and δ min is the minimum value of the preset rotor relative angle range interval.

[0102] Preferably, the adjusting unit 705 is configured to update the rotor angular velocity based on the angular velocity deviation amount, so as to dynamically adjust the angular velocity of the grid-forming energy storage in the new energy sending system in real time, and improve the power angle stability of the grid-forming energy storage.

[0103] The new energy sending system grid-forming energy storage power angle stability control system 700 of the embodiment of the present application corresponds to the new energy sending system grid-forming energy storage power angle stability control method 100 of another embodiment of the present application, and will not be described here.

[0104] The present application has been described by referring to a few embodiments. However, it is well known to those skilled in the art that other embodiments, etc. within the scope of the present application are equivalent to the above disclosed embodiments.

[0105] Generally, all terms used in the present application are interpreted according to their usual meanings in the technical field, unless otherwise explicitly defined therein. All references to "a / the / that [device, component, etc.]" are interpreted as at least one instance of the device, component, etc., unless otherwise explicitly stated. The steps of any method disclosed herein do not necessarily have to be run in the exact order disclosed, unless explicitly stated.

[0106] Those skilled in the art will appreciate that embodiments of the application can be readily used as software, hardware, or a combination of software and hardware. In one

[0107] 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 flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0108] 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 flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0109] 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 flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or a combination thereof. These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0110] Finally, it should be noted that the above-described embodiments are merely intended for describing and illustrating, not limiting, the technical solution of the present application. Although the present application has been 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 by equivalents without departing from the spirit and scope of the present application, and any modification or replacement should be covered within the protection scope of the present application.

Claims

1. A method for controlling the power angle stability of a grid-type energy storage system in a new energy transmission system, characterized in that, The method includes: Obtain the inherent parameters of the new energy transmission system and determine the parameters of the dual PI control loop; The rotor relative angle of the new energy transmission system is calculated in real time based on the inherent parameters. When the rotor relative angle is not within the preset rotor relative angle range, calculate the angle deviation. Based on the aforementioned angle deviation, the angular velocity deviation is calculated through a dual PI control circuit. The rotor angular velocity is updated based on the angular velocity deviation, and the angular velocity of the grid-type energy storage in the new energy transmission system is dynamically adjusted to improve the power angle stability of the grid-type energy storage. The step of calculating the rotor relative angle of the new energy transmission system in real time based on the inherent parameters includes: Where δ is the rotor relative angle; J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronizer; ω0 is the reference value of the angular velocity of the virtual synchronizer; P ref P1 is the active power command value for grid-type energy storage; P2 is the active power output of grid-type energy storage. The method uses the rotor relative angle δ between the PCC point and the infinite power grid as the input, outputs the angular velocity deviation Δω after passing through a dual PI control loop and a limiting loop, and adds the angular velocity deviation Δω to the active power loop; wherein, during a fault, if δ > δ max Then, through the dual PI control loop, Δω2 = 0 and Δω1 < 0 are obtained, thereby suppressing the rotor relative angle δ from continuously increasing; if δ < δ min Then, through the dual PI control loop, Δω2 < 0 and Δω1 = 0 are obtained, thereby suppressing the rotor relative angle δ from continuously decreasing; Δω1 and Δω2 are the angle deviations obtained through the dual PI control loop, respectively; δ max The maximum value within the preset rotor relative angle range; δ min This is the minimum value within the preset rotor relative angle range.

2. The method according to claim 1, characterized in that, The new energy transmission system includes at least one new energy device and one grid-type energy storage device. All devices are connected to the power grid through a common PCC and are distributed in a decentralized manner in the system. All devices can respond to fluctuations in local power grid frequency and voltage.

3. The method according to claim 1, characterized in that, When the relative angle of the rotor is within the preset range of relative angles of the rotor, the angle deviation is 0.

4. A power angle stability control system for a medium-sized grid-type energy storage system in a new energy transmission system, characterized in that, The system includes: The parameter determination unit is used to acquire the inherent parameters of the new energy transmission system and determine the parameters of the dual PI control loop. The rotor relative angle calculation unit is used to calculate the rotor relative angle of the new energy transmission system in real time based on the inherent parameters. An angular deviation calculation unit is used to calculate the angular deviation when the relative angle of the rotor is not within the preset range of the relative angle of the rotor. An angular velocity deviation calculation unit is used to calculate the angular velocity deviation based on the angular deviation and through a dual PI control circuit. An adjustment unit is used to update the rotor angular velocity based on the angular velocity deviation, dynamically adjust the angular velocity of the grid-type energy storage in the new energy transmission system, and improve the power angle stability of the grid-type energy storage. The rotor relative angle calculation unit calculates the rotor relative angle of the new energy transmission system in real time based on the inherent parameters, including: Where δ is the rotor relative angle; J is the virtual inertia coefficient; D is the virtual damping coefficient; ω is the angular velocity of the virtual synchronizer; ω0 is the reference value of the angular velocity of the virtual synchronizer; P ref P1 is the active power command value for grid-type energy storage; P2 is the active power output of grid-type energy storage. The system uses the rotor relative angle δ between the PCC point and the infinite power grid as input, outputs the angular velocity deviation Δω after passing through a dual PI control loop and a limiting loop, and adds the angular velocity deviation Δω to the active power loop; wherein, during a fault, if δ > δ max Then, through the dual PI control loop, Δω2 = 0 and Δω1 < 0 are obtained, thereby suppressing the rotor relative angle δ from continuously increasing; if δ < δ min Then, through the dual PI control loop, Δω2 < 0 and Δω1 = 0 are obtained, thereby suppressing the rotor relative angle δ from continuously decreasing; Δω1 and Δω2 are the angle deviations obtained through the dual PI control loop, respectively; δ max The maximum value within the preset rotor relative angle range; δ min This is the minimum value within the preset rotor relative angle range.

5. The system according to claim 4, characterized in that, The new energy transmission system includes at least one new energy device and one grid-type energy storage device. All devices are connected to the power grid through a common PCC and are distributed in a decentralized manner in the system. All devices can respond to fluctuations in local power grid frequency and voltage.

6. The system according to claim 4, characterized in that, When the relative angle of the rotor is within the preset range of relative angles of the rotor, the angle deviation is 0.

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