Power angle amplitude limiting-based transient oscillation suppression method and system for grid-forming type energy storage power station

Abstract

The invention discloses a power angle amplitude limiting-based transient oscillation suppression method and a power angle amplitude limiting-based transient oscillation suppression system for a grid-forming type energy storage power station, which relate to the technical field of power grid regulation, and are used for judging the power angle turn-back state of the system in advance in a non-over-limit but unstable critical state by identifying the dynamic trend characteristics of a power angle in real time, so as to suppress transient oscillation of the grid-forming type energy storage power station. Whether external boosting is needed or not is judged in combination with evaluation on the turn-back energy release capacity, and regulation and control delay caused by only depending on passive amplitude limiting is avoided. Meanwhile, the power angle is effectively guided to fall back to a stable interval by finely controlling the auxiliary power consistent with the network-forming energy storage injection direction, and an over-compensation suppression mechanism of the boosting process and a turn-back state cooperative control mechanism among multiple energy storage nodes are arranged in a matched mode. The dynamic response capacity and the oscillation suppression effect of the system under the boundary disturbance working condition are remarkably improved, substantial instability caused by seeking not to exceed the limit is prevented, and the supporting capacity of the net-forming type energy storage system for the recovery process after extreme disturbance is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power grid regulation, in particular to a grid-forming energy storage power station transient oscillation suppression method and system based on power angle limiting. BACKGROUND

[0002] With the wide application of grid-forming energy storage technology in power systems, its role in system transient stability control is becoming increasingly important. Grid-forming energy storage refers to an energy storage system that has the ability to build a power grid. In the operation process, it can not only transmit power to the power grid, but also actively adjust key parameters such as frequency, voltage and phase of the power grid. When a disturbance occurs in the power system (such as short circuit, trip or load surge), the grid-forming energy storage system can quickly respond to provide dynamic support for the system, suppress power angle oscillation and improve system stability. In the prior art, the power angle limiting-based method is usually used to realize the suppression control of grid-forming energy storage on transient oscillation: the power angle difference between the voltage phase at the connection between the energy storage and the power grid and the power grid phase is monitored in real time, when the power angle deviation approaches a certain set power angle limiting threshold, the controller reduces the active output of the energy storage or changes to absorb power, so as to provide virtual damping effect and suppress the further deviation of the power angle; when the power angle starts to fall, appropriate active power is injected, which is equivalent to applying a boost to help the system return to a stable state. The whole process is like setting a limit on both sides of the power angle swing to prevent it from deviating too much and losing stability.

[0003] However, this method has a key but easily overlooked control blind area: under some extreme disturbances, the power angle of the system may not have really exceeded the limiting threshold, but it has not yet returned to a stable operating state, but has a short-term return and fall near the threshold. In this state, since the power angle does not trigger the over-limit mechanism, the grid-forming energy storage controller will not make any adjustment; on the other hand, the power angle has not returned to the extent that it is determined to be stable, so it will not trigger the boost behavior. As a result, a control logic gap is formed, that is, the system is in an unstable falling state, but the controller is in a waiting state. If such a return state occurs frequently, the system may be in a power angle fluctuation state for a long time, showing a surface non-exceeding, actual unstable sub-stable state. More seriously, when multiple energy storage nodes are in such a return interval but do not respond actively, it may cause regional phase synchronization failure, phase coupling chaos, and eventually lead to cascading system instability and even splitting. SUMMARY

[0004] The purpose of this invention is to solve the problem mentioned in the background art that the power angle limiting strategy only triggers control when the power angle exceeds a preset threshold, resulting in an adjustment window, leading to regional phase synchronization failure, phase coupling disorder, and ultimately a chain reaction of system instability. Therefore, this invention proposes a transient oscillation suppression method and system for grid-type energy storage power stations based on power angle limiting.

[0005] A first aspect of this invention provides a method for suppressing transient oscillations in grid-connected energy storage power stations based on power angle limiting, the method comprising: During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics. Based on the characteristics of the power angle change trend, determine whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identify it as a power angle reversal state; Based on the identification of the power angle reversal state, assess the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is sufficient to support the system to naturally stabilize. When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is activated to provide auxiliary power that matches the power angle reversal direction by adjusting the active power output mode of the energy storage device, so as to guide the power angle to continue to fall back to the stable range. During the boost compensation adjustment process, the trend of power angle change is continuously monitored. When the power angle is detected to have returned to the stable range, the boost compensation adjustment is terminated to avoid triggering new oscillations. During the boost compensation regulation of grid-type energy storage, return status indication information is sent to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units.

[0006] Optionally, the steps for dynamically analyzing the power angle information within a preset time window to obtain the power angle change trend characteristics are as follows: Within a preset time window, the power angle values ​​at multiple consecutive moments between the grid-type energy storage and the grid connection node are collected as the power angle value sequence corresponding to the preset time window. Calculate the first and second derivatives of the numerical sequence of the power angle to obtain the first and second derivative sequences; use the first derivative sequence as the characteristic of the power angle direction change; use the second derivative sequence as the characteristic of the power angular velocity change. The first-order derivative sequence and the second-order derivative sequence are used as characteristics of the change trend of the work angle.

[0007] Optionally, the steps for identifying a power angle reversal state are as follows: The current power angle value is compared with the set power angle limiting threshold and stable interval threshold. If the current power angle value is between the limiting threshold and the stable interval threshold, and the derivative values ​​of the current time and several adjacent times in the first derivative sequence are all negative or show a trend of changing from positive to negative, and the derivative values ​​of the current time and adjacent times in the second derivative sequence are continuously negative, then it is determined that the current time is in the power angle reversal state, that is, the power angle has started to decrease but the decreasing speed is gradually slowing down and has not yet stabilized and fallen back.

[0008] Optionally, the steps to determine whether the energy release capacity is insufficient to support the system's natural stabilization are as follows: After identifying that the grid-type energy storage is in a power angle reversal state, the absolute value integral of the product of the first and second derivatives is calculated based on the power angle first and second derivative sequences at the current time and its adjacent times to obtain the energy release capacity index. The energy release capacity index is compared with a preset threshold. If the energy release capacity index is lower than the preset threshold, it is determined that the current fallback momentum of the system is insufficient to support the natural stabilization of the system.

[0009] Optionally, the steps to guide the power angle to continue falling back into the stable region are as follows: If it is determined that the grid-type energy storage is in a power angle reversal state and the current energy release capacity is lower than the preset threshold, the boost compensation adjustment operation will be initiated. If the power angle is decreasing from a higher value to a stable range, the grid-type energy storage is controlled to inject positive active power into the grid; if the power angle is increasing from a lower value to a stable range, the grid-type energy storage is controlled to absorb active power, so that the power adjustment direction of the energy storage device is consistent with the target direction of the power angle falling back, so as to accelerate the return of the power angle to the stable range. Based on the difference between the currently calculated energy release capacity index and the preset energy release capacity threshold, the active power output amplitude required for boost compensation is determined according to the preset method. The grid-type energy storage device is controlled to output active power in accordance with the direction and active power output amplitude, so as to guide the power angle to continue to fall back to the stable range.

[0010] Optionally, during the boost compensation adjustment process, the trend of power angle change is continuously monitored. When the power angle is detected to have returned to the stable range, the boost compensation adjustment is terminated to avoid triggering new oscillations. When it is detected that the power angle has returned to the stable range, the power angle fall-off stability index and the power angle relative change stability index are calculated according to the power angle change trend. The power angle fall-off stability index and the power angle relative change stability index are added together to obtain the stopping index. The stop index is compared with the preset stop index threshold. If the stop index is not less than the preset stop index threshold, the boost compensation adjustment is terminated to avoid triggering new oscillations. If the stopping index is less than the preset stopping index threshold, the boost compensation adjustment will continue until the stopping index is not less than the preset stopping index threshold.

[0011] Optionally, the calculation steps for the power angle fall-off stability index are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence. Calculate the second and third derivatives of the power angle value sequence to obtain the second and third derivative sequences; Calculate the standard deviation of the second derivative sequence and the standard deviation of the third derivative sequence, add the standard deviations of the second derivative sequence and the third derivative sequence together, and take the reciprocal of the sum as the stable value after the fallback. Divide the fallback stability value by the preset fallback stability value threshold to obtain the power angle fallback stability index.

[0012] Optionally, the calculation steps for the relative change stability index of the work angle are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence; the power angle value sequence is then divided into several intervals, and the power angle value sequence of each interval is recorded as the interval power angle value sequence. For each interval power angle value sequence, the difference between the initial power angle value and the final power angle value of the interval power angle value sequence is calculated as the power angle change amplitude; and the mean of the interval power angle value sequence is calculated. The power angle change amplitude is then compared with the average power angle value within the interval to obtain the relative change amplitude of the corresponding interval. Calculate the mean and standard deviation of the relative change amplitude for all intervals, and divide the standard deviation of the relative change amplitude by the mean of the relative change amplitude to obtain the stable value of the relative change. Dividing the relative change stability value by a preset threshold yields the power angle relative change stability index.

[0013] Optionally, during the boost compensation regulation of grid-type energy storage, the steps of sending foldback status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units are as follows: While the target energy storage unit identifies that the power angle is in a reversal state and initiates boost compensation adjustment, it generates reversal state indication information containing the unique identifier of the current node, the adjustment start time, the adjustment direction, and the adjustment power amplitude. The turnaround status indication information is sent to other energy storage units through the side channel communication mechanism set within the grid-type energy storage group. The side channel communication mechanism includes the area controller broadcast channel, point-to-point message channel, or dispatch master station distribution channel. After receiving the foldback status indication information, each receiving grid-type energy storage unit determines whether to suspend local regulation behavior, delay regulation response, or adjust regulation gain parameters according to the preset coordination strategy, so as to avoid superimposed interference with the regulation actions of the energy storage unit currently being regulated.

[0014] A second aspect of this invention provides a transient oscillation suppression system for grid-type energy storage power stations based on power angle limiting, the system comprising: Feature module: During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics; State recognition module: Based on the characteristics of the power angle change trend, it determines whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identifies it as a power angle reversal state; Judgment module: Based on the identification of the power angle reversal state, evaluate the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is sufficient to support the system to naturally return to stability; Adjustment module: When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is controlled to start boost compensation adjustment. By adjusting the active power output mode of the energy storage device, auxiliary power matching the power angle reversal direction is provided to guide the power angle to continue to fall back to the stable range. Suppression module: During the boost compensation adjustment process, it continuously monitors the trend of power angle change. When it detects that the power angle has returned to the stable range, it terminates the boost compensation adjustment to avoid triggering new oscillations. Broadcast module: During the boost compensation regulation of grid-type energy storage, it sends back status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units. The beneficial effects of this invention are: This invention proposes a transient oscillation suppression method and system for grid-type energy storage power stations based on power angle limiting. By identifying the dynamic trend characteristics of the power angle in real time, the system can determine the power angle reversal state in advance when it is in a critical state that is not exceeding the limit but not stable. Combined with the assessment of the reversal energy release capacity, it determines whether external boost is needed, avoiding the control lag caused by relying solely on passive limiting. At the same time, by finely controlling the auxiliary power injected in the same direction as the grid-type energy storage, the power angle is effectively guided back to the stable range. It is equipped with an overcompensation suppression mechanism for the boost process and a collaborative control mechanism for the reversal state among multiple energy storage nodes, which significantly improves the dynamic response capability and oscillation suppression effect of the system under boundary disturbance conditions, prevents substantial instability due to "seemingly not exceeding the limit", and enhances the support capability of the grid-type energy storage system for the recovery process after extreme disturbances. Attached Figure Description

[0015] Figure 1 A flowchart illustrating a transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting, provided in an embodiment of the present invention; Figure 2 A framework diagram of a grid-type energy storage power station transient oscillation suppression system based on power angle limiting, provided for an embodiment of the present invention. Detailed Implementation

[0016] To further illustrate the technical means and effects adopted by the present invention in order to achieve the intended purpose, the following detailed description is provided in conjunction with the accompanying drawings and preferred embodiments, based on the specific implementation methods, structures, features and effects of the present invention.

[0017] The present invention provides a method for suppressing transient oscillations in grid-connected energy storage power stations based on power angle limiting. See also... Figure 1 , Figure 1 A flowchart illustrating a transient oscillation suppression method for grid-connected energy storage power stations based on power angle limiting, provided in an embodiment of the present invention. The method includes the following steps: S1. During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics. S2. Based on the characteristics of the power angle change trend, determine whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identify the operating state that meets the above conditions as the power angle reversal state. S3. Based on the identification of the power angle reversal state, assess the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is insufficient to support natural stabilization. S4. When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is activated to start the boost compensation adjustment. By adjusting the active power output mode of the energy storage device, auxiliary power matching the power angle reversal direction is provided to guide the power angle to continue to fall back to the stable range. S5. During the boost compensation adjustment process, continuously monitor the trend of power angle change. When it is detected that the power angle has returned to the stable range, terminate the boost compensation adjustment to avoid triggering new oscillations. S6. During the boost compensation regulation of grid-type energy storage, send turnback status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units.

[0018] Based on the transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting provided in this invention, the dynamic trend characteristics of the power angle are identified in real time. In the critical state where the system is not exceeding limits but is not stable, the power angle reversal state is determined in advance. Combined with the assessment of the reversal energy release capacity, it is determined whether external boost is needed, avoiding the control lag caused by relying solely on passive limiting. Simultaneously, by finely controlling the auxiliary power injected in the same direction as the grid-type energy storage, the power angle is effectively guided back to the stable range. It is also equipped with an overcompensation suppression mechanism for the boost process and a collaborative control mechanism for the reversal state among multiple energy storage nodes. This significantly improves the system's dynamic response capability and oscillation suppression effect under boundary disturbance conditions, preventing substantial instability due to seemingly not exceeding limits, and enhancing the grid-type energy storage system's support capability for the recovery process after extreme disturbances.

[0019] In one embodiment, S1, during the operation of a grid-connected energy storage power station, the steps of real-time acquisition of power angle information between the grid-connected energy storage and the grid connection nodes, and dynamic analysis of the power angle information within a preset time window to obtain the power angle change trend characteristics are as follows: Within a preset time window, the power angle values ​​at multiple consecutive moments between the grid-type energy storage and the grid connection node are collected as the power angle value sequence corresponding to the preset time window. Calculate the first and second derivatives of the numerical sequence of the power angle to obtain the first and second derivative sequences; use the first derivative sequence as the characteristic of the power angle direction change; use the second derivative sequence as the characteristic of the power angular velocity change. The first-order derivative sequence and the second-order derivative sequence are used as characteristics of the change trend of the work angle.

[0020] It should be noted that power angle information refers to the phase difference between the output voltage phase of a grid-connected energy storage power station and the voltage phase at its grid connection point (usually the common coupling point, PCC). It reflects the relative synchronization state between the energy storage system and the grid and is a crucial parameter for judging the system's power exchange behavior and dynamic stability. In practical engineering, this power angle value is typically obtained through a phasor measurement unit (PMU) or a phase-locked loop (such as a PLL embedded in a virtual synchronizing machine, VSG) within the grid controller, and is generally output continuously at a sampling period of milliseconds. The acquisition method can use the instantaneous voltage phase θ1 recorded internally by the grid-connected energy storage controller and the voltage phase θ2 from the grid connection point; the difference between the two, δ = θ1 − θ2, is the real-time power angle value. The preset time window refers to a sliding time interval of a certain duration (e.g., 500ms, 1s, or 2s) used to collect continuous power angle values ​​within this time period, forming a power angle sequence δ(t). For example, if the window is set to 1 second and the sampling period is 20ms, then the window will contain 50 power angle points. By calculating the first derivative (approximately representing the rate of change of power angle) and the second derivative (approximately representing the acceleration of change of power angle) of these 50 points, the directional change trend characteristics and velocity change trend characteristics of the power angle can be obtained respectively. These characteristics can be used to identify whether the power angle is in a boundary reversal state and to help determine whether it is necessary to enter the boost adjustment process.

[0021] It should be noted that the advantages of determining the power angle change trend characteristics through the above method are as follows: First, without relying on the power angle value at a single moment, it comprehensively identifies the dynamic evolution trend of the power angle during the disturbance process, avoiding the omission of potential hidden states that have actually entered the decline or oscillation phase due to the instantaneous power angle value not exceeding the limit. The first derivative reflects whether the power angle is currently rising or falling, while the second derivative reveals whether the rate of change of the power angle is accelerating or slowing down. The combination of the two can accurately identify whether the power angle is in a critical reversal state, providing a more accurate basis for judging whether boost compensation needs to be activated subsequently. Compared with the traditional method of judging whether the limit is exceeded solely based on the power angle value, this method can identify hidden states that are not exceeded but unstable in advance, making up for the response blind spot of the traditional power angle limiting strategy under boundary conditions, improving the dynamic identification and active adjustment capability of the grid-type energy storage system for transient oscillations, thereby achieving more timely and accurate disturbance suppression control.

[0022] In one embodiment, S2, the step of determining whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range based on the power angle change trend characteristics, and identifying the operating state that meets the above conditions as the power angle reversal state, is as follows: The current power angle value is compared with the set power angle limiting threshold and stable interval threshold. If the current power angle value is between the limiting threshold and the stable interval threshold, and the derivative values ​​of the current time and several adjacent times in the first derivative sequence are all negative or show a trend of changing from positive to negative, and the derivative values ​​of the current time and adjacent times in the second derivative sequence are continuously negative, then it is determined that the current time is in the power angle reversal state, that is, the power angle has started to decrease but the decreasing speed is gradually slowing down and has not yet stabilized and fallen back.

[0023] It should be noted that the power angle limiting threshold and the stability interval threshold are two key boundary parameters used to determine the current power angle state of the grid-type energy storage system. The power angle limiting threshold refers to the maximum allowable power angle deviation of the grid-type energy storage system under transient disturbance conditions. Exceeding this threshold will trigger the system's limiting protection or adjustment mechanism. It is typically set based on system operating characteristics, protection margins, and synchronization stability requirements, such as within ±60 degrees. The stability interval threshold, on the other hand, is used to determine whether the power angle has essentially recovered to the system's perceived safe and stable state. It is usually set at a position far below the limiting threshold, such as ±30 degrees or ±25 degrees, to avoid prematurely determining that the system has stabilized. When the current power angle value is between these two thresholds, it indicates that the system is in a "critical reversal interval," meaning the power angle has not exceeded the limit but has not yet returned to stability. To determine whether the system is in a "reversal state," the trend is further assessed by combining the first and second derivatives of the power angle: if the first derivative is negative at the current moment and in its vicinity, it indicates that the power angle is decreasing; if the second derivative is negative, it indicates that the rate of decrease is slowing down, meaning the descent momentum is weakening, and the system may not be able to stabilize naturally. Taking a real-world scenario as an example, assuming the power angle limit threshold is 60 degrees and the stability interval threshold is 30 degrees, the current power angle at a certain node is 45 degrees, which has entered the critical interval; simultaneously, observing the first derivative sequence reveals that the power angle has changed from increasing to decreasing (e.g., from +3° / s to -1° / s), and the second derivative is negative (the rate of decrease has decreased from -3° / s to -1° / s). Therefore, it can be comprehensively determined that the system is currently in a power angle reversal state. Even if the current power angle value seems to be within the limit, the controller should be alert that the system has fallen into an unsteady state of "weak descent," thus laying the foundation for whether to trigger boost control subsequently.

[0024] The advantage of using the above method to determine and identify whether the power angle is in a reversal state is that it can accurately identify the critical transition zone where the system is "not overlimited but not stable," avoiding the control gaps and response delays caused by traditional control strategies that rely solely on whether the power angle exceeds the limit threshold. This judgment mechanism not only considers whether the current power angle value falls within the "reversal zone" (i.e., between the limit threshold and the stable zone threshold), but also introduces the analysis of the first and second derivatives of the power angle, making the judgment more dynamic and trend-aware: the first derivative is used to determine whether the power angle has changed from rising to falling, while the second derivative is used to determine whether the decline is slowing down, i.e., whether the current system is "losing its downward momentum" and is thus in a potential unstable edge state. Through joint trend judgment, potential unstable trends can be proactively identified before the system actually triggers the protection mechanism, enabling earlier and more targeted intervention and control. For example, if the current power angle is 48 degrees, which is below the 60-degree limiting threshold but above the 30-degree stabilization threshold, and if the trend judgment shows that the power angle has started to decrease but the rate of decrease has slowed down rapidly, then although the system "appears to be falling back", it is actually likely to be stuck in the high power angle fluctuation range. At this time, timely identification and marking as a return state is beneficial to the subsequent activation of the auxiliary adjustment mechanism of the system, effectively avoiding complex system-level risks such as phase unlocking and resonant coupling caused by "chronic instability" or the superposition of multiple node disturbances.

[0025] In one embodiment, S3, based on identifying a power angle reversal state, assessing the energy release capability during the current power angle reversal process, and determining whether the energy release capability is insufficient to support natural stabilization, is the following step: After identifying that the grid-type energy storage is in a power angle reversal state, the absolute value integral of the product of the first and second derivatives is calculated based on the first and second derivative sequences of the power angle at the current moment to obtain the energy release capacity index. The energy release capacity index is compared with a preset threshold. If the energy release capacity index is lower than the preset threshold, it is determined that the current downward momentum is insufficient and not enough to support natural stabilization.

[0026] It should be noted that when a system is identified as being in a power angle reversal state, it cannot be assumed that it will naturally recover to a stable state simply because the power angle is decreasing. Instead, it is necessary to further assess whether the system's "reversal momentum" is sufficient, that is, whether its energy release capacity is enough to support the power angle continuing to decrease into the stable range. The implementation method is as follows: First, determine an analysis time window that includes the current moment and several sampling points before and after it. For example, select 5 sampling points before and after to form a window with a total length of approximately 200ms. Extract the power angle first derivative sequence (representing the rate of change of the power angle) and the second derivative sequence (representing the trend of velocity change, i.e., acceleration) within this window. Then, for each pair of time points, multiply the first derivative value by the corresponding second derivative value and take the absolute value to represent the "instantaneous intensity of energy release" at that moment. Finally, integrate or sum all the instantaneous intensities within the time window to obtain the total energy release capacity index. This indicator reflects the actual "vibration damping energy" released by the system during the power angle reversal process. If this indicator is significantly low, it indicates that although the power angle is decreasing, its speed is not fast and the downward trend is continuously weakening, meaning the system lacks power and may stall in the middle, unable to enter the stable region by its own inertia. Therefore, this energy release capacity indicator is compared with an empirically set safe stabilization threshold. For example, if the threshold is set to 0.2, and the calculated indicator is only 0.08, it indicates that the system's current energy release is insufficient, and it should be judged as "insufficient fallback kinetic energy," requiring subsequent controller intervention for boost adjustment. To illustrate with a practical example, suppose the current first derivative sequence of the power angle is [-2.5, -2.0, -1.5, -1.2, -0.9], and the second derivative sequence is [-0.5, -0.4, -0.3, -0.2, -0.1]. Then the absolute value of the product corresponding to each pair of time points is [1.25, 0.8, 0.45, 0.24, 0.09], and its integral value is 2.83. If the preset threshold is 3.5, then it is judged that the energy release is insufficient, indicating that although the power angle is decreasing, the trend is rapidly weakening, and the system may fall into a semi-steady state and cannot automatically return to the safe operating range. Compared with the traditional method of judging only by observing the rate of change of the power angle, this method more accurately combines the dual dynamic characteristics of "descending direction" and "changing trend", enabling the system to judge the risk of failure to fall back early, thereby buying time for subsequent active adjustment.

[0027] In one embodiment, S4, when it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is controlled to start boost compensation adjustment. By adjusting the active power output mode of the energy storage device, auxiliary power matching the power angle reversal direction is provided to the system to guide the power angle to continue to fall back to the stable range. If it is determined that the grid-type energy storage is in a power angle reversal state and the current energy release capacity is lower than the preset threshold, the boost compensation adjustment operation will be initiated. If the power angle is decreasing from a higher value to a stable range, the grid-type energy storage is controlled to inject positive active power into the grid; if the power angle is increasing from a lower value to a stable range, the grid-type energy storage is controlled to absorb active power, so that the power adjustment direction of the energy storage device is consistent with the target direction of the power angle falling back, so as to accelerate the return of the power angle to the stable range. Based on the difference between the currently calculated energy release capacity index and the preset energy release capacity threshold, the active power output amplitude required for boost compensation is determined according to the preset method. The grid-type energy storage device is controlled to output active power in accordance with the direction and active power output amplitude, so as to guide the power angle to continue to fall back to the stable range.

[0028] In one implementation, the step of determining the active power output amplitude required for boost compensation according to a preset method based on the difference between the currently calculated energy release capacity index and the preset energy release capacity threshold is as follows: the absolute value is integrated or accumulated within a window to form the current energy release capacity index, denoted as E. n Then, it is compared with the preset energy release capacity threshold E. t By comparison, the difference ΔE = E is obtained. t -E n This characterizes the degree of insufficiency of the current system's falling momentum. The preset method refers to determining the magnitude of the active power that the energy storage device should output, i.e., P, based on the product of this difference ΔE and the adjustment coefficient K. a =K×ΔE, where K can be set as a fixed proportional coefficient or a dynamically adjusted factor based on factors such as system capacity and dynamic response rate. For example, if the preset energy release capacity threshold E... t The calculated E is 3.0. n With a value of 1.6 and an adjustment coefficient K of 0.5, ΔE = 1.4, and the calculated boost power is P. a =0.5×1.4=0.7, indicating that the current energy storage should inject 0.7 pu of active power into the grid (or absorb the same amount of power in the direction of power angle recovery) to provide dynamic compensation and drive the power angle to continue to decrease towards the stable range. The advantage of this method is that by setting the power output through "differential driving", the adjustment intensity is proportional to the actual system deficit, which has quantifiability, adjustability and engineering feasibility, avoiding the risk of over-compensation or under-compensation caused by blindly fixing the output power, thereby achieving more refined dynamic stability control.

[0029] It should be noted that by controlling the start-up boost compensation regulation of grid-type energy storage in the above manner, and adjusting the active power output mode of the energy storage device, auxiliary power is provided to the system in a direction matching the power angle return. This effectively guides the power angle to continue falling back into the stable range, and the benefits of achieving transient oscillation suppression in grid-type energy storage power stations are as follows: First, the boost compensation regulation can provide the required power in a timely manner during the power angle return process, avoiding system stagnation or insufficient return due to insufficient return power, thereby avoiding "dead zones" or "metastable states" and improving the dynamic stability of the system; Second, by adjusting the energy release capacity and preset threshold... The difference between the values ​​is used to precisely adjust the boost power, which can provide quantitative adjustment power according to the actual situation of the system, avoiding the problems of over-compensation or under-compensation and ensuring the accuracy of adjustment. For example, when the power angle falls back from a higher value to the stable range, the energy storage device injects positive active power to help the system stabilize faster; while when the power angle is rising from a lower value, the energy storage device absorbs active power to avoid excessive rise or oscillation of the system. In this way, the power angle stabilizes faster and smoother, and the risk of loss of synchronization or disconnection caused by excessive instantaneous oscillation is effectively reduced, thus improving the safety and reliability of the power grid.

[0030] In one embodiment, S5, during the boost compensation adjustment process, continuously monitoring the power angle change trend, and terminating the boost compensation adjustment when the power angle has recovered to the stable range to avoid triggering new oscillations, is as follows: When it is detected that the power angle has returned to the stable range, the power angle fall-off stability index and the power angle relative change stability index are calculated according to the power angle change trend. The power angle fall-off stability index and the power angle relative change stability index are added together to obtain the stopping index. The stop index is compared with the preset stop index threshold. If the stop index is not less than the preset stop index threshold, the boost compensation adjustment is terminated to avoid triggering new oscillations. If the stopping index is less than the preset stopping index threshold, the boost compensation adjustment will continue until the stopping index is not less than the preset stopping index threshold.

[0031] In one implementation, the calculation steps for the power angle fallback stability index are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence. Calculate the second and third derivatives of the power angle value sequence to obtain the second and third derivative sequences; Calculate the standard deviation of the second derivative sequence and the standard deviation of the third derivative sequence, add the standard deviations of the second derivative sequence and the third derivative sequence together, and take the reciprocal of the sum as the stable value after the fallback. Divide the fallback stability value by the preset fallback stability value threshold to obtain the power angle fallback stability index.

[0032] It should be noted that the data acquisition method involved in calculating the power angle fall-off stability index is as follows: First, power angle value sequences are collected by real-time monitoring of the power angle information between the grid-connected energy storage and the power grid nodes. These power angle values ​​are acquired within a preset time period, typically a time window of power angle change, and data is collected at sampling intervals (e.g., every second or every few milliseconds). The power angle data sequences are obtained through power angle sensors or real-time calculation and recording by power system real-time monitoring equipment. Then, using these collected power angle value sequences, the second and third derivatives of the power angle are calculated sequentially, representing the rate of change of the power angle and the rate of change of acceleration. These values ​​reflect the dynamic stability during the power angle fall-off process. The standard deviation is calculated through statistical analysis of the second and third derivative sequence data, thus providing data support for the subsequent calculation of the fall-off stability value and the power angle fall-off stability index.

[0033] It should be noted that the power angle fallback stability index is mainly used to measure the stability of the system during the power angle fallback process, reflecting whether the fallback is smooth and close to the ideal stable state of the system. Specifically, this index quantifies the fluctuation of the power angle fallback by calculating the standard deviation of the second derivative (acceleration) and the third derivative (rate of change of acceleration) during the power angle change process. If the standard deviation of the second and third derivatives is large, it means that the instability of the power angle fallback process is strong, which may lead to oscillations or rebounds. When the power angle fallback stability index is large, it indicates that the fluctuations during the power angle fallback process are small and tend to be stable. At this time, the system has recovered to the stable range and there is no risk of further rebound. Therefore, when the power angle fallback stability index is large, it means that the system's stabilization process is stable enough, and it is safe to terminate the boost compensation adjustment to avoid further adjustment that may cause new oscillations. Conversely, if the stability index during the power angle decline is small, it means the system is not yet stable, and there is a risk of instability or oscillation during the decline process. Therefore, it is necessary to continue boost compensation adjustment until the stability index reaches the preset threshold to ensure the system returns to a fully stable state, thereby avoiding new oscillations or instability caused by premature termination of adjustment. For example, when the power angle changes drastically, the system needs more adjustment to alleviate the unstable decline. However, when the power angle change is stable and the stability index increases, the system can stop adjustment to avoid instability caused by over-adjustment, thereby ensuring stable operation of the system during the transient process and achieving the effect of transient oscillation suppression.

[0034] The advantage of calculating the power angle fallback stability index using the above method is that it can more accurately quantify the dynamic changes during the power angle fallback process and effectively capture whether the system has recovered to stability. First, by calculating the second and third derivatives of the power angle, the acceleration and changes in acceleration during the fallback can be reflected, which are crucial indicators during system recovery. The second derivative reflects the degree of acceleration during the fallback, while the third derivative further reveals the changes in acceleration, helping to determine if there is an unstable trend during the fallback. Second, by calculating the standard deviations of the second and third derivatives, the fluctuation amplitude during the fallback process can be quantified. The smaller the standard deviation, the more stable the power angle change, the smoother the fallback process, and the closer the system is to a stable state. Therefore, adding the standard deviations of the second and third derivatives allows for a comprehensive assessment of the stability during the fallback process, helping to determine when it is time to terminate the adjustment. Finally, by normalizing the fallback stability value by dividing it by a preset threshold, the stability index can be ensured to have a standardized value, facilitating comparison with the preset stop index threshold. The advantage of this method is that it can accurately determine whether the power angle has stabilized and ensure that the adjustment process does not stop too early or too late, thereby avoiding new oscillations or system instability caused by inaccurate judgment.

[0035] In one implementation, the calculation steps for the stability index of the relative change in work angle are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence; the power angle value sequence is then divided into several intervals, and the power angle value sequence of each interval is recorded as the interval power angle value sequence. For each interval power angle value sequence, the difference between the initial power angle value and the final power angle value of the interval power angle value sequence is calculated as the power angle change amplitude; and the mean of the interval power angle value sequence is calculated. The power angle change amplitude is then compared with the average power angle value within the interval to obtain the relative change amplitude of the corresponding interval. Calculate the mean and standard deviation of the relative change amplitude for all intervals, and divide the standard deviation of the relative change amplitude by the mean of the relative change amplitude to obtain the stable value of the relative change. Dividing the relative change stability value by a preset threshold yields the power angle relative change stability index.

[0036] It should be noted that in the calculation of the power angle relative change stability index mentioned above, the power angle data acquisition method is as follows: After the system identifies that the power angle has recovered to the stable range, it immediately starts the data acquisition module to continuously acquire real-time power angle values ​​from the connection point between the grid-type energy storage power station and the grid. These power angle values ​​can be obtained in real time through a synchronous phasor measurement device (PMU) or a voltage-current phasor calculation model, with the unit being angles (°). Data is continuously collected according to a preset sampling period (e.g., every 20 milliseconds or less), forming a power angle value sequence covering a set time period (e.g., 2 seconds, 5 seconds, or 10 seconds). This sequence is stored chronologically and subsequently divided into multiple intervals, each containing an equal number of sampling points, thereby generating multiple interval power angle value sequences for subsequent calculations.

[0037] It should be noted that the relative stability index of power angle change is a quantitative indicator used to measure whether the power angle change of a grid-type energy storage power station tends to stabilize after the recovery from a transient disturbance. Its core function is to determine whether the boost compensation adjustment can be terminated and the system can enter the natural steady-state recovery stage. This index divides the power angle values ​​collected within a preset time period into multiple continuous intervals, calculates the change amplitude between the start and end values ​​of the power angle in each interval, and takes the ratio of this amplitude to the mean power angle of the interval as the relative change amplitude. Then, it further calculates the standard deviation and mean of the relative change amplitudes of all intervals, and takes the ratio of the standard deviation to the mean as the relative stability value reflecting the consistency and regularity of the power angle change. Finally, it is normalized to the 0~1 interval to form the final relative stability index of power angle change. The larger the value, the more consistent the relative amplitude of the power angle change in each interval and the more stable the overall change. The reason for continuing to calculate this index even after the power angle has returned to the stable range is that the return of the power angle to within the numerical threshold does not necessarily mean the end of the dynamic process; there may still be risks of slight fluctuations or a new round of reverse oscillations. The power angle relative change stability index is a key tool for identifying such pseudo-steady states. If the index value is large, it indicates that the power angle changes in each interval are relatively concentrated, and the system has entered a stable natural oscillation convergence process, allowing for safe termination of compensation adjustments. If the index value is still small, it indicates that the power angle changes still exhibit random fluctuations or unclear trends, requiring continued boosting to prevent power angle rebound or secondary oscillations. For example, if the power angle of a certain energy storage node has returned to the stable range, but the power angle changes in multiple micro-periods are chaotic and disordered, resulting in a low calculated stability index, it indicates that although the numerical value appears stable, it is actually potentially unstable. Conversely, if the power angle changes in all intervals decrease uniformly and the stability index is high, then the power angle stabilization can be considered genuine and reliable. Therefore, the essence of this index is to introduce a "structural steady state" judgment mechanism on top of the numerical steady state, so as to ensure that the adjustment behavior exits in time after the physical system has truly stabilized, thereby avoiding new power angle deviation or system oscillation caused by adjustment lag, and realizing the true closed-loop suppression of transient oscillations by grid-type energy storage power stations.

[0038] It should be noted that the advantage of calculating the relative change stability index of the power angle using the above method is that it avoids the shortcomings of traditional methods based on derivatives and acceleration, such as instability under boundary states, sensitivity to high-frequency disturbances, or susceptibility to occasional spikes. Instead, it takes a more structural and trend-oriented approach, constructing a stability evaluation mechanism for the overall power angle fluctuation pattern based on the relative change amplitude of the power angle value over multiple time intervals. Specifically, this method calculates the ratio between the difference between the first and last power angle values ​​in each time interval and the average value, thus truly reflecting the effective change intensity of the power angle at the current scale in that interval, without relying on the existence of local slopes or peaks. Then, it calculates the mean and standard values ​​of the relative change amplitudes across all intervals. This approach introduces a measure of the distribution characteristic of "whether the amplitude of change is concentrated," ultimately normalizing the ratio of standard deviation to mean into a stability index in the 0-1 range. This index is dimensionless, unitless, and facilitates threshold judgment. Its advantage lies not only in reflecting whether the power angle change tends to stabilize but also in judging the consistency of the trend, avoiding misjudgments of "false stability" due to local disturbances and mitigating the problem of abnormally high partial derivatives caused by noise. It is particularly suitable for the "critical reversal segment" where the power angle has numerically stabilized but structural fluctuations have not completely dissipated. This allows for a more scientific identification of whether regulation should be terminated, thereby achieving highly robust transient stability control logic and avoiding repeated system oscillations caused by over-regulation or timeouts. In one embodiment, S6, during the boost compensation regulation of grid-type energy storage, the step of sending foldback status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units is as follows: While the target energy storage unit identifies that the power angle is in a reversal state and initiates boost compensation adjustment, it generates reversal state indication information containing the unique identifier of the current node, the adjustment start time, the adjustment direction, and the adjustment power amplitude. The turnaround status indication information is sent to other energy storage units through the side channel communication mechanism set within the grid-type energy storage group. The side channel communication mechanism includes, but is not limited to, the area controller broadcast channel, the point-to-point message channel, or the dispatch master station distribution channel. After receiving the foldback status indication information, each receiving grid-type energy storage unit determines whether to suspend local regulation behavior, delay regulation response, or adjust regulation gain parameters according to the preset coordination strategy, so as to avoid superimposed interference with the regulation actions of the currently regulated energy storage unit, thereby improving the stability and accuracy of multi-energy storage coordinated regulation.

[0039] It should be noted that the purpose of sending foldback status indication information to other grid-type energy storage units in the above steps is to achieve dynamic adjustment and coordination among multiple energy storage units, and to avoid system-level instability problems such as superposition of adjustment power, amplification of disturbance or aggravation of oscillation caused by multiple energy storage units responding independently at the same time during local disturbance response. When an energy storage unit detects that its power angle is in a foldback state and initiates boost compensation regulation, it indicates that the node has taken priority in assuming the initial regulation responsibility for this disturbance. Therefore, it is necessary to immediately generate a foldback status indication message containing key information such as the unique identifier of the energy storage unit, the regulation initiation time, the regulation direction (injection or absorption), and the regulation power amplitude. This message should be sent to other grid-connected energy storage units within the same grid area through the pre-set communication mechanism within the grid-connected energy storage system (such as the broadcast mechanism of the regional coordination controller, point-to-point communication links between energy storage units, or the unified distribution channel of the grid dispatch master station). This allows these units to respond cooperatively based on their respective local strategies after receiving the instruction. For example, if they are about to enter the foldback judgment logic stage, they can choose to postpone execution, enter an observation period, or adjust their local regulation gain coefficient to reduce the regulation response sensitivity, ensuring that the actions of the current main regulation node are not "superimposed interference" or "reverse cancellation" by other nodes. Furthermore, if If the receiving unit detects that the current main regulating node's regulation direction is opposite to its own possible regulation direction (e.g., the main node injects power into the grid while it expects to absorb it), it can directly enter a waiting state. This avoids power offsetting that could cause ineffective oscillations or system energy asymmetry. Ultimately, through this lightweight but real-time regulation and coordination mechanism, the grid-type energy storage group can achieve rapid master-slave cooperation logic when multiple nodes face disturbances simultaneously. This improves the overall response stability of the system to boundary state disturbances and the global adaptability of local regulation behavior. For example, in a typical scenario, three energy storage units are deployed at different physical distances on the same bus. When a sudden load fluctuation at one end triggers a power angle reversal and the nearest energy storage unit starts regulation, the reversal status indication information it sends can enable the two remote energy storage units to recognize that a main regulating node has already intervened. They can then proactively choose not to intervene in this regulation, effectively preventing voltage fluctuations or frequency swings caused by the simultaneous regulation of the three energy storage nodes. This ensures the hierarchical order and response flexibility of the overall regulation and control system.

[0040] Based on the same inventive concept, embodiments of the present invention also provide a transient oscillation suppression system for grid-type energy storage power stations based on power angle limiting. See also Figure 2 , Figure 2 A schematic diagram of the transient oscillation suppression system for a grid-type energy storage power station based on power angle limiting, provided in an embodiment of the present invention, includes: Feature module: During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics; State recognition module: Based on the characteristics of the power angle change trend, it determines whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identifies it as a power angle reversal state; Judgment module: Based on the identification of the power angle reversal state, evaluate the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is sufficient to support the system to naturally return to stability; Adjustment module: When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is controlled to start boost compensation adjustment. By adjusting the active power output mode of the energy storage device, auxiliary power matching the power angle reversal direction is provided to guide the power angle to continue to fall back to the stable range. Suppression module: During the boost compensation adjustment process, it continuously monitors the trend of power angle change. When it detects that the power angle has returned to the stable range, it terminates the boost compensation adjustment to avoid triggering new oscillations. Broadcast module: During the boost compensation regulation of grid-type energy storage, it sends back status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units.

[0041] Based on the transient oscillation suppression system for grid-type energy storage power stations provided in this invention embodiment, the system identifies the dynamic trend characteristics of the power angle in real time. In the critical state where the system is not exceeding limits but is not yet stable, the system determines the power angle reversal state in advance. Combined with an assessment of the reversal energy release capacity, it judges whether external boost is needed, avoiding the control lag caused by relying solely on passive limiting. Simultaneously, by finely controlling the auxiliary power injected in the same direction as the grid-type energy storage, the system effectively guides the power angle back to the stable range. It is also equipped with an overcompensation suppression mechanism for the boost process and a collaborative control mechanism for the reversal state among multiple energy storage nodes. This significantly improves the system's dynamic response capability and oscillation suppression effect under boundary disturbance conditions, preventing substantial instability due to "seemingly not exceeding limits," and enhancing the grid-type energy storage system's support capability for the recovery process after extreme disturbances.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A method for suppressing transient oscillations in grid-type energy storage power stations based on power angle limiting, characterized in that, Includes the following steps: During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics. Based on the characteristics of the power angle change trend, determine whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identify it as a power angle reversal state; Based on the identification of the power angle reversal state, assess the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is sufficient to support natural stabilization. When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is activated to provide auxiliary power that matches the power angle reversal direction by adjusting the active power output mode of the energy storage device, so as to guide the power angle to continue to fall back to the stable range. During the boost compensation adjustment process, the trend of power angle change is continuously monitored. When the power angle is detected to have returned to the stable range, the boost compensation adjustment is terminated to avoid triggering new oscillations. During the boost compensation regulation of grid-type energy storage, return status indication information is sent to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units.

2. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, The steps for dynamically analyzing the power angle information within a preset time window to obtain the power angle change trend characteristics are as follows: Within a preset time window, the power angle values ​​at multiple consecutive moments between the grid-type energy storage and the grid connection node are collected as the power angle value sequence corresponding to the preset time window. Calculate the first and second derivatives of the power angle numerical sequence to obtain the first and second derivative sequences; use the first derivative sequence as the characteristic of the power angle direction variation; use the second derivative sequence as the characteristic of the power angular velocity variation. The first-order derivative sequence and the second-order derivative sequence are used as characteristics of the change trend of the work angle.

3. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, The steps to identify a state of power angle reversal are as follows: The current power angle value is compared with the set power angle limiting threshold and stable interval threshold. If the current power angle value is between the limiting threshold and the stable interval threshold, and the derivative values ​​of the current time and several adjacent times in the first derivative sequence are all negative or show a trend of changing from positive to negative, and the derivative values ​​of the current time and adjacent times in the second derivative sequence are continuously negative, then it is determined that the power angle is in a state of reversal.

4. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, The steps to determine whether the energy release capacity is insufficient to support natural stabilization are as follows: After identifying that the grid-type energy storage is in a power angle reversal state, the energy release capacity index is obtained by calculating the absolute value integral of the product of the first and second derivatives based on the first and second derivative sequences of the power angle at the current moment. The energy release capacity index is then compared with a preset threshold. If the energy release capacity index is lower than the preset threshold, it is determined that the current downward momentum is insufficient and cannot support natural stabilization.

5. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, The steps to guide the work angle back towards the stable range are as follows: If it is determined that the grid-type energy storage is in a power angle reversal state and the current energy release capacity is lower than the preset threshold, the boost compensation adjustment operation will be initiated. If the power angle is decreasing from a higher value to a stable range, the grid-type energy storage is controlled to inject positive active power into the grid; if the power angle is increasing from a lower value to a stable range, the grid-type energy storage is controlled to absorb active power, so that the power adjustment direction of the energy storage device is consistent with the target direction of the power angle falling back. Based on the difference between the currently calculated energy release capacity index and the preset energy release capacity threshold, the active power output amplitude required for boost compensation is determined according to the preset method, and the grid-type energy storage device is controlled to output active power according to the direction and active power output amplitude.

6. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, During boost compensation adjustment, the trend of power angle change is continuously monitored. When the power angle is detected to have returned to the stable range, the boost compensation adjustment is terminated to avoid triggering new oscillations. The steps are as follows: When it is detected that the power angle has returned to the stable range, the power angle fall-off stability index and the power angle relative change stability index are calculated according to the power angle change trend. The power angle fall-off stability index and the power angle relative change stability index are added together to obtain the stopping index. The stop index is compared with the preset stop index threshold. If the stop index is not less than the preset stop index threshold, the boost compensation adjustment is terminated to avoid triggering new oscillations. If the stopping index is less than the preset stopping index threshold, the boost compensation adjustment will continue until the stopping index is not less than the preset stopping index threshold.

7. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 6, characterized in that, The calculation steps for the power angle fallback stability index are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence. Calculate the second and third derivatives of the power angle value sequence to obtain the second and third derivative sequences; Calculate the standard deviation of the second derivative sequence and the standard deviation of the third derivative sequence, add the standard deviations of the second derivative sequence and the third derivative sequence together, and take the reciprocal of the sum as the stable value after the fallback. Divide the fallback stability value by the preset fallback stability value threshold to obtain the power angle fallback stability index.

8. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 6, characterized in that, The calculation steps for the relative change stability index of the power angle are as follows: When the power angle is detected to have recovered to the stable range, the power angle is continuously acquired for a preset time period to obtain a power angle value sequence; the power angle value sequence is then divided into several intervals, and the power angle value sequence of each interval is recorded as the interval power angle value sequence. For each interval power angle value sequence, the difference between the initial power angle value and the final power angle value of the interval power angle value sequence is calculated as the power angle change amplitude; and the mean of the interval power angle value sequence is calculated. The power angle change amplitude is then compared with the average power angle value within the interval to obtain the relative change amplitude of the corresponding interval. Calculate the mean and standard deviation of the relative change amplitude for all intervals, and divide the standard deviation of the relative change amplitude by the mean of the relative change amplitude to obtain the stable value of the relative change. Dividing the relative change stability value by a preset threshold yields the power angle relative change stability index.

9. The transient oscillation suppression method for grid-type energy storage power stations based on power angle limiting according to claim 1, characterized in that, During the boost compensation regulation of grid-type energy storage, the steps to send turnback status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units are as follows: While the target energy storage unit identifies that the power angle is in a reversal state and initiates boost compensation adjustment, it generates reversal state indication information containing the unique identifier of the current node, the adjustment start time, the adjustment direction, and the adjustment power amplitude. The turnaround status indication information is sent to other energy storage units through the side channel communication mechanism set within the grid-type energy storage group. The side channel communication mechanism includes the area controller broadcast channel, point-to-point message channel, or dispatch master station distribution channel. After receiving the foldback status indication information, each receiving grid-type energy storage unit determines whether to suspend local regulation behavior, delay regulation response, or adjust regulation gain parameters according to the preset coordination strategy, so as to avoid superimposed interference with the regulation actions of the energy storage unit currently being regulated.

10. A transient oscillation suppression system for a grid-type energy storage power station based on power angle limiting, used to implement the transient oscillation suppression method for a grid-type energy storage power station based on power angle limiting as described in any one of claims 1-9, characterized in that, The system includes: Feature module: During the operation of the grid-type energy storage power station, the power angle information between the grid-type energy storage and the grid connection node is collected in real time, and the power angle information is dynamically analyzed within a preset time window to obtain the power angle change trend characteristics; State recognition module: Based on the characteristics of the power angle change trend, it determines whether the power angle is in a critical reversal state that has not exceeded the power angle limit threshold but has not yet returned to the stable range, and identifies it as a power angle reversal state; Judgment module: Based on the identification of the power angle reversal state, evaluate the energy release capacity during the current power angle reversal process and determine whether the energy release capacity is sufficient to support natural stabilization; Adjustment module: When it is determined that the energy release capacity is insufficient under the power angle reversal state, the grid-type energy storage is controlled to start boost compensation adjustment. By adjusting the active power output mode of the energy storage device, auxiliary power matching the power angle reversal direction is provided to guide the power angle to continue to fall back to the stable range. Suppression module: During the boost compensation adjustment process, it continuously monitors the trend of power angle change. When it detects that the power angle has returned to the stable range, it terminates the boost compensation adjustment to avoid triggering new oscillations. Broadcast module: During the boost compensation regulation of grid-type energy storage, it sends back status indication information to other grid-type energy storage units to coordinate the regulation behavior of multiple energy storage units and prevent superimposed interference between different grid-type energy storage units.

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