A method and device for evaluating the whole-station self-synchronization voltage source characteristics of a network-constructed new energy station

Abstract

The present application relates to the technical field of new energy power generation grid-connected performance evaluation, and specifically provides a method and device for evaluating the whole-station self-synchronous voltage source characteristics of a grid-constructing new energy station, comprising: applying a disturbance to the grid-connected point of the grid-constructing new energy station, and obtaining disturbance response data of the grid-constructing new energy station; determining key evaluation indexes representing the whole-station self-synchronous voltage source characteristics of the grid-constructing new energy station based on the disturbance response data; and evaluating the whole-station self-synchronous voltage source characteristics of the grid-constructing new energy station based on the key evaluation indexes. The technical scheme provided by the present application can comprehensively and quantitatively reflect the operation quality of the grid-constructing new energy station as a self-synchronous voltage source.

Description

Technical Field

[0001] This invention relates to the field of performance evaluation technology for grid-connected new energy power generation, specifically to a method and device for evaluating the characteristics of the self-synchronizing voltage source of a grid-connected new energy power station. Background Technology With the increasing penetration rate of new energy sources, the power system exhibits characteristics such as low inertia, strong nonlinearity, and weak disturbance immunity, posing severe challenges to the frequency and voltage stability of the power grid. Traditional new energy power generation adopts grid-following control based on phase-locked loops (PLLs). Grid-Forming (GFM) control technology, by simulating the operation mechanism of synchronous generators, controls the amplitude and phase of the converter output voltage, enabling it to connect to the grid as a self-synchronizing voltage source. Grid-Forming converters abandon traditional PLLs and achieve grid-connected operation through a power-frequency self-synchronization mechanism, exhibiting voltage source characteristics. Droop control and virtual synchronous machine (VSG) control are currently the most mainstream grid-forming self-synchronizing control strategies. They can spontaneously provide instantaneous power support when the grid experiences disturbances, possessing active inertia / frequency / voltage support capabilities.

[0002] However, existing technologies have the following shortcomings: First, existing evaluation methods for grid-connected renewable energy mainly focus on individual converters or single devices, lacking methods for characterizing and evaluating the self-synchronizing voltage source characteristics at the overall renewable energy power station level. For example, existing patents propose a voltage support assessment method for renewable energy bases including grid-connected energy storage, but this method emphasizes voltage support topology analysis and fails to comprehensively characterize the internal potential characteristics of the entire power station. Similarly, existing patents propose evaluation methods for the dynamic voltage support capability of grid-connected equipment using grid-connected converters, but these only evaluate individual grid-connected converters and do not involve an overall evaluation of the power station.

[0003] Second, the core characteristic of grid-connected renewable energy lies in its ability to maintain a constant internal potential amplitude and frequency (phase angle) under grid-connection disturbances when connected as a self-synchronizing voltage source. When a system fault occurs, the grid-connected equipment should provide instantaneous and rapid support without sudden changes in potential amplitude. However, existing evaluation indicators (such as short-circuit ratio and inertia assessment) fail to directly reflect the ability of internal potential amplitude and frequency to maintain stability under disturbance conditions, and lack targeted quantitative evaluation methods.

[0004] Third, as the scale of grid-type renewable energy power plants continues to expand, the functional requirements in current grid-type standards / specifications mainly involve inertia response, islanded operation, weak grid adaptability, black start, active damping, and phase angle change tolerance tests. However, the test requirements in these standards are mainly geared towards the equipment or unit level, lacking a comprehensive evaluation system for the characteristics of self-synchronizing voltage sources at the entire power plant level.

[0005] Therefore, there is an urgent need to propose a method that can comprehensively characterize and evaluate the operating characteristics of grid-connected new energy power stations as self-synchronizing voltage sources from the perspective of the entire power station, especially to evaluate their ability to maintain constant internal potential amplitude and frequency (phase angle) when subjected to various disturbances at the grid connection point. Summary of the Invention

[0006] To overcome the above-mentioned defects, this invention proposes a method and device for evaluating the characteristics of the self-synchronizing voltage source of a grid-type new energy power station.

[0007] Firstly, a method for evaluating the self-synchronization voltage source characteristics of a grid-type renewable energy power station is provided, the method comprising: Disturbances are applied to the grid connection points of grid-connected renewable energy power plants to obtain disturbance response data of the grid-connected renewable energy power plants; Based on the disturbance response data, key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire grid-type new energy power station are determined. The characteristics of the self-synchronizing voltage source of the entire grid-type new energy power station are evaluated based on the aforementioned key evaluation indicators.

[0008] Preferably, the disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

[0009] Furthermore, the voltage amplitude disturbance includes voltage sag, voltage surge, and continuous voltage fluctuation. A voltage sag is defined as the voltage amplitude at the grid connection point decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage surge is defined as the voltage amplitude at the grid connection point increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the voltage amplitude at the grid connection point fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance includes sudden frequency change and continuous frequency fluctuation. The sudden frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance is a sudden change in the phase of the grid-connected voltage at the grid connection point, ranging from ±10° to ±30°, with a change time of 0.02 to 0.1 seconds.

[0010] Preferably, the disturbance response data includes: the internal potential amplitude and phase angle during the disturbance process.

[0011] Preferably, the key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

[0012] Furthermore, the internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

[0013] Furthermore, the internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

[0014] Furthermore, the comprehensive self-synchronizing voltage source characteristic indicators include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e(-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθ maxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

[0015] Furthermore, the evaluation of the overall self-synchronization voltage source characteristics of grid-type renewable energy power stations based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

[0016] Secondly, a device for evaluating the characteristics of the self-synchronizing voltage source of a grid-type renewable energy power station is provided, the device comprising: The acquisition module is used to apply disturbances to the grid connection point of the grid-connected renewable energy power station and acquire the disturbance response data of the grid-connected renewable energy power station. The determination module is used to determine the key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire station of the grid-type new energy power station based on the disturbance response data; The evaluation module is used to evaluate the characteristics of the self-synchronization voltage source of the entire grid-type new energy power station based on the key evaluation indicators.

[0017] Preferably, the disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

[0018] Furthermore, the voltage amplitude disturbance includes voltage sag, voltage surge, and continuous voltage fluctuation. A voltage sag is defined as the voltage amplitude at the grid connection point decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage surge is defined as the voltage amplitude at the grid connection point increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the voltage amplitude at the grid connection point fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance includes sudden frequency change and continuous frequency fluctuation. The sudden frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance is a sudden change in the phase of the grid-connected voltage at the grid connection point, ranging from ±10° to ±30°, with a change time of 0.02 to 0.1 seconds.

[0019] Preferably, the disturbance response data includes: the internal potential amplitude and phase angle during the disturbance process.

[0020] Preferably, the key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

[0021] Furthermore, the internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

[0022] Furthermore, the internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

[0023] Furthermore, the comprehensive self-synchronizing voltage source characteristic indicators include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e (-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθ maxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

[0024] Furthermore, the evaluation of the overall self-synchronization voltage source characteristics of grid-type renewable energy power stations based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

[0025] Thirdly, a computer device is provided, comprising: one or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the method for evaluating the characteristics of the whole-station self-synchronization voltage source of the grid-type new energy power station is implemented.

[0026] Fourthly, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed, the method for evaluating the characteristics of the whole-station self-synchronization voltage source of the grid-type new energy power station is implemented.

[0027] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects: This invention provides a method and apparatus for evaluating the self-synchronization voltage source characteristics of a grid-connected renewable energy power station, comprising: applying a disturbance to the grid connection point of the grid-connected renewable energy power station and acquiring disturbance response data of the grid-connected renewable energy power station; determining key evaluation indicators characterizing the self-synchronization voltage source characteristics of the grid-connected renewable energy power station based on the disturbance response data; and evaluating the self-synchronization voltage source characteristics of the grid-connected renewable energy power station based on the key evaluation indicators. The technical solution provided by this invention fills the technical gap in power station-level self-synchronization voltage source evaluation, specifically: This invention takes the maintenance of constant internal potential amplitude and frequency (phase angle) under grid connection point disturbance as the core evaluation objective, and constructs a multi-level evaluation index system including internal potential amplitude maintenance index, internal potential phase angle maintenance index and comprehensive index, which can comprehensively and quantitatively reflect the operation quality of grid-connected new energy power stations as self-synchronizing voltage sources.

[0028] This invention provides a standardized multi-type disturbance test scheme, including voltage amplitude disturbance, frequency disturbance, phase angle change disturbance and composite disturbance, which can cover various disturbance scenarios that grid-type new energy power plants may encounter in actual power grid operation, ensuring the comprehensiveness and representativeness of the evaluation results.

[0029] This invention establishes a scientific rating system. Through clear indicator threshold division, the evaluation results are intuitive and comparable, facilitating engineering applications and industry benchmarking. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the main steps of the evaluation method for the characteristics of the self-synchronizing voltage source of a grid-type new energy power station according to an embodiment of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1 See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a method for evaluating the characteristics of a self-synchronizing voltage source in a grid-type renewable energy power station according to an embodiment of the present invention. Figure 1 As shown, the method for evaluating the characteristics of the self-synchronization voltage source of a grid-type renewable energy power station in this embodiment of the invention mainly includes the following steps: Step S101: Apply a disturbance to the grid connection point of the grid-connected renewable energy power station and obtain the disturbance response data of the grid-connected renewable energy power station; Step S102: Based on the disturbance response data, determine the key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire grid-type new energy power station; Step S103: Evaluate the characteristics of the self-synchronization voltage source of the entire grid-type new energy power station based on the key evaluation indicators.

[0034] In this embodiment, the disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

[0035] In one embodiment, the voltage amplitude disturbance is caused by adjusting the upstream grid voltage or connecting a reactive power compensation device at the grid connection point, resulting in changes in the voltage amplitude at the grid connection point. Specifically, this includes voltage sag, voltage swell, and continuous voltage fluctuation. A voltage sag is defined as the grid connection point voltage amplitude decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage swell is defined as the grid connection point voltage amplitude increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the grid connection point voltage amplitude fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance is caused by adjusting the grid frequency to cause the grid connection point frequency to change in the following ways: abrupt frequency change and continuous frequency fluctuation. The abrupt frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance causes a sudden change in the voltage phase at the grid connection point through a phase jump device, resulting in a change of ±10° to ±30° in the voltage phase at the grid connection point, with a change time of 0.02 to 0.1 s.

[0036] In this embodiment, the disturbance response data includes: the internal potential amplitude and phase angle during the disturbance process, which can be obtained using one of the following methods: Method 1 (based on dynamic equivalent model): Construct a state-space model of the entire power station. For the k-th grid-type generating unit within the power station, its internal potential amplitude Ek and phase angle θk are determined by its control strategy. For a unit using virtual synchronous machine (VSG) control, its active power-frequency control equation is: J·dω k / dt = P refk - P outk - D·(ω k - ω0) dθk / dt = ω k Its reactive power-voltage control equation is: Ek = E0 + k q ·(Q refk - Q outk ) In the formula: J is the virtual inertia coefficient, D is the damping coefficient, and P... refk P is the active power reference value. outk ω represents the actual output active power. k Here, ω0 is the virtual angular frequency, E0 is the rated angular frequency, and k is the rated voltage amplitude. qQ is the reactive power-voltage droop factor. refk Q is the reactive power reference value. outk This represents the actual output reactive power.

[0037] Based on the internal potential amplitude and phase angle of each unit, and combined with the impedance parameters of the collector lines within the station, the equivalent internal potential amplitude and equivalent internal potential phase angle of the entire station are obtained through power flow calculation or weighted averaging.

[0038] Method 2 (Based on Terminal Voltage Back-Calculation): Using the measured voltage UPCC(t) and current IPCC(t) at the grid connection point, the equivalent internal potential is calculated using the following formula based on the equivalent impedance Zeq of the power station: E(t)·e jθ(t) = UPCC(t)·e jφu(t) + Z eq ·I PCC (t)·e jφi(t) In the formula: Zeq is the equivalent impedance of the entire station, which can be obtained by calculation or online identification through the station topology parameters; UPCC(t) is the voltage amplitude at the grid connection point; IPCC(t) is the current amplitude at the grid connection point; φu(t) is the voltage phase angle at the grid connection point; φi(t) is the current phase angle at the grid connection point; e is the natural constant; and j is the imaginary unit.

[0039] In this embodiment, the key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

[0040] In one embodiment, the internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

[0041] In one embodiment, the internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

[0042] In one embodiment, the integrated self-synchronizing voltage source characteristics include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e (-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθ maxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

[0043] In one implementation, the evaluation of the whole-station self-synchronization voltage source characteristics of the grid-type renewable energy power station based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

[0044] In one specific implementation, the present invention further defines "excellent" and "good" ratings, specifically as follows: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 5%, recovery time of internal potential amplitude tErecovery ≤ 0.5s, maximum deviation rate of equivalent frequency Δfmax ≤ 0.5%, synchronization recovery time of internal potential phase angle tθsync ≤ 0.5s, quality factor of self-synchronization voltage source QVS ≥ 0.90, and internal potential constant maintenance capability index CIE ≥ 0.85, the whole-station self-synchronization voltage source of the grid-type new energy power station is excellent.

[0045] When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 10%, recovery time of internal potential amplitude tErecovery ≤ 1.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 1.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 1.0s, quality factor of self-synchronization voltage source QVS ≥ 0.75, and internal potential constant maintenance capability index CIE ≥ 0.70, the whole-station self-synchronization voltage source of the grid-type new energy power station is good.

[0046] In one application scenario, taking a grid-connected wind farm as an example, the wind farm has a total installed capacity of 100MW, comprising 50 grid-connected wind turbines with a single unit capacity of 2MW. The wind farm's power is collected via a 35kV collection line and then connected to the grid through a 110kV step-up substation. All wind turbines employ a virtual synchronous generator (VSG) control strategy, enabling them to operate in a grid-connected configuration.

[0047] Step 1: Obtain station operation data Voltage and current transformers are installed at the 110kV grid connection point of the wind farm, with a sampling frequency set to 10kHz. The instantaneous values ​​of three-phase voltage (ua(t), ub(t), uc(t)) and three-phase current (ia(t), ib(t), ic(t)) are continuously collected. Simultaneously, information such as the operating status, output power, and control parameters of each unit is obtained through the wind farm monitoring system.

[0048] Step 2: Calculate the equivalent internal potential magnitude and phase angle Establish an equivalent circuit model of the wind farm. Based on the topology of the wind farm, calculate the equivalent impedance of the 35kV collector line and the 110kV transmitter line, Zeq = 0.02 + j0.15 pu (based on 100MW).

[0049] The equivalent internal potential is calculated using the terminal voltage inverse method. For each sampling time, based on the measured voltage UPCC(t) and current IPCC(t) at the grid connection point, the equivalent internal potential is calculated using the following formula: E(t)·e jθ(t) = UPCC(t)·e jφu(t) + Z eq ·I PCC (t)·e jφi(t) The time series of equivalent internal potential amplitude and equivalent internal potential phase angle are calculated in real time by using dq transformation or symmetrical component method.

[0050] Step 3: Conduct disturbance tests At the 110kV grid connection point of the wind farm, the following disturbances are sequentially applied through a grid disturbance generator: (1) Voltage sag disturbance: The voltage amplitude at the grid connection point drops from the rated value (1.0 pu) to 0.7 pu within 0.1s, and then recovers to the rated value after 2s. Record E(t) and θ(t) throughout the process.

[0051] (2) Voltage surge disturbance: The voltage amplitude at the grid connection point rises from the rated value (1.0 pu) to 1.2 pu within 0.1s, and then returns to the rated value after 2s. Record E(t) and θ(t) throughout the process.

[0052] (3) Frequency sudden change disturbance: The grid connection point frequency is deviated from 50Hz to 49.5Hz (-0.5Hz deviation) within 0.2s, and then returns to 50Hz after 10s. Record E(t) and θ(t) throughout the process.

[0053] (4) Phase angle sudden change disturbance: causing a sudden jump of +20° in the phase of the voltage at the grid connection point, with a sudden change time of 0.05s. Record E(t) and θ(t) throughout the process.

[0054] (5) Composite disturbance: A voltage drop disturbance (0.7 pu, lasting 2 s) and a frequency change disturbance (49.5 Hz, lasting 10 s) are applied sequentially, with a time interval of 5 s between them. Record E(t) and θ(t) throughout the process.

[0055] Step 4: Extract evaluation indicators Based on the recorded data, calculate each evaluation index. Take voltage sag disturbance (0.7 pu) as an example: Maximum deviation rate of internal potential amplitude ΔEmax: During the voltage sag, E(t) drops from 1.0 pu to a minimum of 0.94 pu, ΔEmax = 6.0%.

[0056] Internal potential amplitude recovery time tErecovery: After voltage recovery, E(t) recovers to the range of 1.0±0.02pu within 0.3s, tErecovery = 0.3s.

[0057] Steady-state deviation rate of internal potential amplitude ΔEss: After the disturbance, under the new steady state, E(t) = 1.0 pu, ΔE_ss = 0%.

[0058] Taking a sudden frequency change disturbance (49.5Hz) as an example: Equivalent frequency maximum deviation rate Δfmax: During the frequency deviation process, the lowest equivalent internal potential frequency is 49.55Hz, Δfmax = 0.9%.

[0059] Internal potential phase angle synchronization recovery time tθsync: After frequency recovery, the phase angle difference recovers to the stable range within 0.4s, tθsync = 0.4s.

[0060] The extreme value of the rate of change of frequency, RoCoFmax, is 0.25 Hz / s.

[0061] Calculate the comprehensive index: The quality factor QVS of the self-synchronizing voltage source is calculated as follows: with weights α_1=α_2=α_3=α_4=0.25 and T_0=1s, QVS=0.82 is obtained.

[0062] Internal potential constant maintenance capability index (CIE): Taking weights β_1=β_2=0.5, the calculated CIE = 0.78.

[0063] Step 5: Give an evaluation conclusion Based on a comprehensive evaluation of various indicators, the maximum deviation rate of the internal potential amplitude of this grid-type wind farm is 6.0% (≤10%), the recovery time of the internal potential amplitude is 0.3s (≤1.0s), the maximum deviation rate of the equivalent frequency is 0.9% (≤1.0%), the synchronization recovery time of the internal potential phase angle is 0.4s (≤1.0s), the quality factor (QVS) of the self-synchronizing voltage source is 0.82 (≥0.75), and the internal potential constant maintenance index (CIE) is 0.78 (≥0.70).

[0064] According to the evaluation grading system, the self-synchronization voltage source characteristics of this grid-type wind farm are rated as good.

[0065] Example 2 Based on the same inventive concept, this invention also provides a device for evaluating the characteristics of the self-synchronization voltage source of a grid-type renewable energy power station. The device for evaluating the characteristics of the self-synchronization voltage source of a grid-type renewable energy power station includes: The acquisition module is used to apply disturbances to the grid connection point of the grid-connected renewable energy power station and acquire the disturbance response data of the grid-connected renewable energy power station. The determination module is used to determine the key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire station of the grid-type new energy power station based on the disturbance response data; The evaluation module is used to evaluate the characteristics of the self-synchronization voltage source of the entire grid-type new energy power station based on the key evaluation indicators.

[0066] Preferably, the disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

[0067] Furthermore, the voltage amplitude disturbance includes voltage sag, voltage surge, and continuous voltage fluctuation. A voltage sag is defined as the voltage amplitude at the grid connection point decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage surge is defined as the voltage amplitude at the grid connection point increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the voltage amplitude at the grid connection point fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance includes sudden frequency change and continuous frequency fluctuation. The sudden frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance is a sudden change in the phase of the grid-connected voltage at the grid connection point, ranging from ±10° to ±30°, with a change time of 0.02 to 0.1 seconds.

[0068] Preferably, the disturbance response data includes: the internal potential amplitude and phase angle during the disturbance process.

[0069] Preferably, the key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

[0070] Furthermore, the internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

[0071] Furthermore, the internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

[0072] Furthermore, the comprehensive self-synchronizing voltage source characteristic indicators include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e (-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθmaxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

[0073] Furthermore, the evaluation of the overall self-synchronization voltage source characteristics of grid-type renewable energy power stations based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

[0074] Example 3 Based on the same inventive concept, this invention also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement corresponding method flows or corresponding functions, thereby realizing the steps of the whole-station self-synchronization voltage source characteristic evaluation method for a grid-type new energy power station in the above embodiments.

[0075] Example 4 Based on the same inventive concept, this invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the whole-station self-synchronization voltage source characteristic evaluation method for a grid-type new energy power station in the above embodiments.

[0076] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the characteristics of the self-synchronizing voltage source of a grid-type renewable energy power station, characterized in that, The method includes: Disturbances are applied to the grid connection points of grid-connected renewable energy power plants to obtain disturbance response data of the grid-connected renewable energy power plants; Based on the disturbance response data, key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire grid-type new energy power station are determined. The characteristics of the self-synchronizing voltage source of the entire grid-type new energy power station are evaluated based on the aforementioned key evaluation indicators.

2. The method as described in claim 1, characterized in that, The disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

3. The method as described in claim 2, characterized in that, The voltage amplitude disturbance includes voltage sag, voltage surge, and continuous voltage fluctuation. A voltage sag is defined as the voltage amplitude at the grid connection point decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage surge is defined as the voltage amplitude at the grid connection point increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the voltage amplitude at the grid connection point fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance includes sudden frequency change and continuous frequency fluctuation. The sudden frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance is a sudden change in the phase of the grid-connected voltage at the grid connection point, ranging from ±10° to ±30°, with a change time of 0.02 to 0.1 seconds.

4. The method as described in claim 1, characterized in that, The disturbance response data includes the internal potential amplitude and phase angle during the disturbance process.

5. The method as described in claim 1, characterized in that, The key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

6. The method as described in claim 5, characterized in that, The internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

7. The method as described in claim 6, characterized in that, The internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

8. The method as described in claim 7, characterized in that, The comprehensive self-synchronization voltage source characteristic indicators include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e (-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθ maxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

9. The method as described in claim 8, characterized in that, The evaluation of the self-synchronization voltage source characteristics of the entire grid-type renewable energy power station based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

10. A device for evaluating the characteristics of a self-synchronizing voltage source in a grid-type renewable energy power station, characterized in that, The device includes: The acquisition module is used to apply disturbances to the grid connection point of the grid-connected renewable energy power station and acquire the disturbance response data of the grid-connected renewable energy power station. The determination module is used to determine the key evaluation indicators characterizing the self-synchronization voltage source characteristics of the entire station of the grid-type new energy power station based on the disturbance response data; The evaluation module is used to evaluate the characteristics of the self-synchronization voltage source of the entire grid-type new energy power station based on the key evaluation indicators.

11. The apparatus as claimed in claim 9, characterized in that, The disturbance includes at least one of the following: voltage amplitude disturbance, frequency disturbance, and phase angle abrupt change disturbance.

12. The apparatus as claimed in claim 11, characterized in that, The voltage amplitude disturbance includes voltage sag, voltage surge, and continuous voltage fluctuation. A voltage sag is defined as the voltage amplitude at the grid connection point decreasing from its rated value to 0.5–0.9 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. A voltage surge is defined as the voltage amplitude at the grid connection point increasing from its rated value to 1.1–1.3 times its rated value within 0.1 seconds, and recovering after 0.5–5 seconds. Continuous voltage fluctuation is defined as the voltage amplitude at the grid connection point fluctuating sinusoidally at a frequency of 0.1–2 Hz and an amplitude of ±0.05–0.2 times its rated value. The frequency disturbance includes sudden frequency change and continuous frequency fluctuation. The sudden frequency change is when the grid connection point frequency deviates from the rated frequency by ±0.2 to 1.0 Hz within 0.2 s and recovers after 1 to 30 s. The continuous frequency fluctuation is when the grid connection point frequency fluctuates sinusoidally with a frequency of 0.05 to 0.5 Hz and an amplitude of ±0.05 to 0.2 Hz. The phase angle abrupt change disturbance is a sudden change in the phase of the grid-connected voltage at the grid connection point, ranging from ±10° to ±30°, with a change time of 0.02 to 0.1 seconds.

13. The apparatus as claimed in claim 9, characterized in that, The disturbance response data includes the internal potential amplitude and phase angle during the disturbance process.

14. The apparatus as claimed in claim 9, characterized in that, The key evaluation indicators include: internal potential amplitude maintenance index, internal potential phase angle maintenance index, and comprehensive self-synchronizing voltage source characteristic index.

15. The apparatus as claimed in claim 14, characterized in that, The internal potential amplitude maintenance index includes: Maximum deviation rate of internal potential amplitude ΔEmax: ΔEmax = max(|E(t) - E0|) / E0 × 100%; Internal potential recovery time tErecovery: The time required from the moment the disturbance occurs until the equivalent internal potential amplitude recovers to and remains within the range of E0×(±εE); Steady-state deviation rate of internal potential amplitude ΔEss: ΔEss = |E(tss) - E0| / E0 × 100%; Where E(t) is the internal potential amplitude at time t, E0 is the equivalent internal potential amplitude reference value during steady-state operation before the disturbance, E(tss) is the equivalent internal potential amplitude under the new steady-state condition after the disturbance, and εE is the internal potential deviation band.

16. The apparatus as claimed in claim 15, characterized in that, The internal potential phase angle maintenance index includes: Maximum phase angle offset of internal potential Δθmax: Δθmax = max(|θ(t) - θref(t)|); The maximum deviation rate of the equivalent frequency Δfmax is: Δfmax = max(|feq(t) - fN|) / fN × 100%; Internal potential phase angle synchronization recovery time tθsync: The time required from the end of the disturbance to the recovery of the phase difference between the internal potential phase angle and the grid connection point voltage phase angle to and continuously maintained within the range of θ0×(±εθ); The extreme value of the rate of change of frequency, RoCoFmax: RoCoFmax = max(|d²θ(t) / dt²|) / (2π); Where θ(t) is the phase angle at time t, θref(t) is the reference phase angle at time t, feq(t) is the equivalent internal potential frequency at time t, feq(t) = (1 / 2π)·dθ(t) / dt, fN is the rated frequency, θ0 is the steady-state phase difference, and εθ is the phase difference deviation band.

17. The apparatus as claimed in claim 16, characterized in that, The comprehensive self-synchronization voltage source characteristic indicators include: Self-synchronizing voltage source quality factor Q VS : Q VS =α1(1-ΔEmax / 100)+α2·e (-tErecovery / T 0 ) +α3(1-Δfmax / 100)+α4·e (-tθsync / T 0 ) ; Internal potential constant maintenance capability index C IE : C IE =β1·(1-∫|E(t)- E0|dt / ( E0·T d ))+β2·(1 - ∫|θ(t)-θref(t)|dt / (Δθ maxref ·T d )) Where α1, α2, α3, and α4 are the first, second, third, and fourth weighting coefficients, respectively, satisfying α1 + α2 + α3 + α4 = 1, T0 is the normalized time constant, and T d Let Δθ be the duration of the disturbance, e be the natural constant, and Δθ be the value of Δθ. maxref To reference the maximum phase angle deviation, β1 and β2 are the fifth and sixth weighting coefficients, respectively, satisfying β1+β2=1.

18. The apparatus as claimed in claim 17, characterized in that, The evaluation of the self-synchronization voltage source characteristics of the entire grid-type renewable energy power station based on the key evaluation indicators includes: When the key evaluation indicators meet the following conditions: maximum deviation rate of internal potential amplitude ΔEmax ≤ 20%, recovery time of internal potential amplitude tErecovery ≤ 2.0s, maximum deviation rate of equivalent frequency Δfmax ≤ 2.0%, synchronization recovery time of internal potential phase angle tθsync ≤ 2.0s, quality factor of self-synchronization voltage source QVS ≥ 0.60, and internal potential constant maintenance capability index CIE ≥ 0.50, the whole-station self-synchronization voltage source of the grid-type new energy power station is qualified.

19. A computer device, characterized in that, include: One or more processors; The processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, the method for evaluating the characteristics of the whole-station self-synchronization voltage source of a grid-type new energy power station as described in any one of claims 1 to 9 is implemented.

20. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements the whole-station self-synchronization voltage source characteristic evaluation method for grid-type new energy power stations as described in any one of claims 1 to 9.

Images