New energy power system overvoltage risk calculation method considering phase-locked loop dynamics

Abstract

The application discloses a new energy power system overvoltage risk calculation method considering the dynamic of a phase-locked loop, comprising the following steps: determining the new energy generator terminal voltage amplitude and the AC bus voltage amplitude of the new energy generator terminal and the AC bus at any time after fault clearance respectively; determining the maximum new energy generator terminal voltage and the maximum AC bus voltage that can be borne by the new energy generator terminal and the AC bus respectively; determining that there is an overvoltage risk when the maximum new energy generator terminal voltage is greater than a preset generator terminal voltage peak value or the maximum AC bus voltage is greater than a preset AC bus voltage peak value; calculating a new energy generator terminal overvoltage risk coefficient according to the new energy generator terminal voltage amplitude or calculating an AC bus overvoltage risk coefficient according to the AC bus voltage amplitude; and performing risk assessment according to the new energy generator terminal overvoltage risk coefficient or the AC bus overvoltage risk coefficient to determine an evaluation result.

Description

Technical Field

[0001] This invention relates to the field of safety and stability analysis technology for high-proportion renewable energy power systems, and more specifically, to a method for calculating overvoltage risk in renewable energy power systems that takes into account phase-locked loop dynamics. Background Technology

[0002] In recent years, with the large-scale commissioning of new energy power sources and the successive commissioning of large-capacity AC / DC transmission projects, my country has formed a basic pattern of high-proportion new energy power generation equipment connected to AC / DC hybrid power grids. Following various fault disturbances, system safety issues, represented by overvoltage, have become increasingly prominent.

[0003] Numerous factors and complex mechanisms contribute to overvoltage in high-proportion renewable energy power systems. Existing research primarily relies on the reactive power surplus generated during renewable energy power system faults and calculates the resulting voltage changes. This research focuses on calculating and analyzing the sources of reactive power and their surplus capacity, neglecting the dynamic effect of the renewable energy power generation equipment control system on system voltage during transient processes. This leads to significant discrepancies between theoretical analysis and simulation results.

[0004] Generally, in high-proportion renewable energy power systems, power system safety issues can arise if the voltage at the renewable energy generator terminals exceeds the overvoltage protection setting or the AC bus voltage exceeds the insulation coordination limit. The phase-locked loop (PLL) is a key component of the renewable energy power generation equipment control system, its main function being to ensure synchronized operation between the renewable energy power generation equipment and the power grid. If the PLL fails to accurately lock onto the grid phase due to abnormal operating conditions, the renewable energy power generation equipment will lose synchronization and subsequently cease operation. However, currently, there is a lack of methods for calculating overvoltage risks in renewable energy power systems that take into account the dynamics of the PLL. Summary of the Invention

[0005] This invention proposes a method for calculating overvoltage risk in new energy power systems that takes into account the dynamics of phase-locked loops, in order to solve the problem of how to assess the risk of overvoltage in high-proportion new energy power systems.

[0006] To address the aforementioned problems, according to one aspect of the present invention, a method for calculating overvoltage risk in a new energy power system considering phase-locked loop dynamics is provided, the method comprising:

[0007] Determine the voltage amplitude at the new energy generator terminal and the AC bus at any time after the fault is cleared;

[0008] Determine the maximum voltage that the new energy generator terminal and the AC bus can withstand, respectively.

[0009] When the maximum value of the new energy generator terminal voltage is greater than the preset generator terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value, it is determined that there is an overvoltage risk.

[0010] Calculate the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal, or calculate the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus.

[0011] Risk assessment is conducted based on the overvoltage risk coefficient of the new energy generator terminal or the overvoltage risk coefficient of the AC bus, and the assessment result is determined.

[0012] Preferably, determining the voltage amplitude at the new energy generator terminal and the AC bus at any moment after the fault is cleared includes:

[0013]

[0014]

[0015] Among them, U r (t) represents the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll (t) represents the phase-locked loop angle at time t; L∑ represents the equivalent reactance from the new energy generator to the infinite power supply; U s (t) represents the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; L represents the d-axis component of the AC bus voltage at time t. g This is the equivalent reactance from the AC bus to the infinite power source.

[0016] Preferably, determining the maximum value of the new energy generator terminal voltage and the maximum value of the AC bus voltage that the new energy generator terminal equipment and the AC bus can withstand includes:

[0017]

[0018]

[0019] Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid.∑ The equivalent reactance from the new energy generator to the infinite power supply; L g This is the equivalent reactance from the AC bus to the infinite power source.

[0020] Preferably, the step of calculating the overvoltage risk coefficient at the new energy generator terminal based on the voltage amplitude at the new energy generator terminal or calculating the overvoltage risk coefficient at the AC bus based on the voltage amplitude at the AC bus includes:

[0021]

[0022]

[0023] Where, k r For terminal overvoltage risk factor; k s For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

[0024] Preferably, the risk assessment is conducted based on the overvoltage risk coefficient at the new energy generator terminal or the overvoltage risk coefficient at the AC bus, and the assessment result is determined, including:

[0025] If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal.

[0026] If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal;

[0027] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk.

[0028] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

[0029] According to another aspect of the present invention, a new energy power system overvoltage risk calculation system considering phase-locked loop dynamics is provided, the system comprising:

[0030] The voltage amplitude determination unit is used to determine the voltage amplitude of the new energy generator terminal and the AC bus at any time after the fault is cleared.

[0031] The maximum voltage determination unit is used to determine the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal and the AC bus can withstand, respectively.

[0032] The judgment unit is used to determine that there is an overvoltage risk when the maximum value of the new energy terminal voltage is greater than the preset terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value.

[0033] The coefficient determination unit is used to calculate the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or to calculate the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus.

[0034] The assessment unit is used to conduct risk assessment based on the overvoltage risk coefficient of the new energy generator terminal or the overvoltage risk coefficient of the AC bus, and to determine the assessment result.

[0035] Preferably, the voltage amplitude determination unit determines the voltage amplitude at the new energy generator terminal and the AC bus at any time after the fault is cleared, including:

[0036]

[0037]

[0038] Among them, U r (t) represents the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll (t) represents the phase-locked angle of the phase-locked loop at time t; L ∑ The equivalent reactance from the new energy generator to the infinite power supply; U s (t) represents the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; L represents the d-axis component of the AC bus voltage at time t. g This is the equivalent reactance from the AC bus to the infinite power source.

[0039] Preferably, the voltage maximum value determination unit determines the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal equipment and the AC bus can withstand, respectively, including:

[0040]

[0041]

[0042] Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid. ∑The equivalent reactance from the new energy generator to the infinite power supply; L g This is the equivalent reactance from the AC bus to the infinite power source.

[0043] Preferably, the coefficient determining unit calculates the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or calculates the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus, including:

[0044]

[0045]

[0046] Where, k r For terminal overvoltage risk factor; k s For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

[0047] Preferably, the assessment unit performs a risk assessment based on the new energy terminal overvoltage risk coefficient or the AC bus overvoltage risk coefficient, and determines the assessment result, including:

[0048] If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal.

[0049] If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal;

[0050] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk.

[0051] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

[0052] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any one of the steps in a method for calculating overvoltage risk in a new energy power system taking into account phase-locked loop dynamics.

[0053] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0054] The aforementioned computer-readable storage medium; and

[0055] One or more processors for executing a program in the computer-readable storage medium.

[0056] This invention provides a method for calculating overvoltage risk in a renewable energy power system that considers the dynamic characteristics of a phase-locked loop (PLL). The method includes: determining the voltage amplitude at the renewable energy generator terminal and the AC bus at any given moment after fault clearance; determining the maximum voltage values ​​at the renewable energy generator terminal and the AC bus that the renewable energy generator terminal and the AC bus can withstand; determining the existence of overvoltage risk when the maximum voltage value at the renewable energy generator terminal is greater than a preset peak voltage value or the maximum voltage value at the AC bus is greater than a preset peak voltage value; calculating the overvoltage risk coefficient at the renewable energy generator terminal based on the voltage amplitude at the renewable energy generator terminal or the overvoltage risk coefficient at the AC bus based on the voltage amplitude at the AC bus; and conducting a risk assessment based on the overvoltage risk coefficient at the renewable energy generator terminal or the overvoltage risk coefficient at the AC bus to determine the assessment result. This invention takes a VSC (Vehicle-Supported Grid-Connected) system as the research object, establishes an analytical calculation model considering the dynamic characteristics of the PLL, reveals the correlation between overvoltage and the PLL in the VSC system, significantly improves the accuracy of overvoltage calculation compared to existing methods, and provides strong support for the safety and stability analysis and control of high-proportion renewable energy power systems by performing risk assessment based on overvoltage. Attached Figure Description

[0057] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0058] Figure 1 A flowchart of a new energy power system overvoltage risk calculation method considering phase-locked loop dynamics according to an embodiment of the present invention;

[0059] Figure 2 This is a topology diagram of a VSC grid-connected system according to an embodiment of the present invention;

[0060] Figure 3 This is a topology diagram of the control loop of a PLL according to an embodiment of the present invention;

[0061] Figure 4 This is a schematic diagram of the equivalent circuit of a VSC grid-connected system according to an embodiment of the present invention;

[0062] Figure 5 This is a schematic diagram of the structure of a new energy power system overvoltage risk calculation system 500 that takes into account phase-locked loop dynamics according to an embodiment of the present invention. Detailed Implementation

[0063] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0064] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0065] Figure 1 This is a flowchart of a method 100 for calculating overvoltage risk in a new energy power system considering phase-locked loop dynamics according to an embodiment of the present invention. Figure 1 As shown, the overvoltage risk calculation method for new energy power systems considering phase-locked loop (PLL) dynamics provided by this invention takes the VSC grid-connected system as the research object, establishes an analytical calculation model considering the dynamic characteristics of the PLL, reveals the correlation between overvoltage and the PLL in the VSC grid-connected system, significantly improves the overvoltage calculation accuracy compared with existing calculation methods, and performs risk assessment based on overvoltage, providing strong support for the safety and stability analysis and control of high-proportion new energy power systems. The overvoltage risk calculation method 100 for new energy power systems considering PLL dynamics provided by this invention starts from step 101, whereby the voltage amplitude at the new energy generator terminal and the AC bus voltage amplitude at any moment after fault clearance are determined.

[0066] Preferably, determining the voltage amplitude at the new energy generator terminal and the AC bus at any moment after the fault is cleared includes:

[0067]

[0068]

[0069] Among them, U r (t) represents the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll(t) represents the phase-locked angle of the phase-locked loop at time t; L ∑ The equivalent reactance from the new energy generator to the infinite power supply; U s (t) represents the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; L represents the d-axis component of the AC bus voltage at time t. g This is the equivalent reactance from the AC bus to the infinite power source.

[0070] In step 102, the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal and the AC bus can withstand are determined respectively.

[0071] Preferably, determining the maximum value of the new energy generator terminal voltage and the maximum value of the AC bus voltage that the new energy generator terminal equipment and the AC bus can withstand includes:

[0072]

[0073]

[0074] Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid. ∑ The equivalent reactance from the new energy generator to the infinite power supply; L g This is the equivalent reactance from the AC bus to the infinite power source.

[0075] In this invention, a grid-connected system model of a voltage source converter (VSC) is established. New energy power generation equipment typically uses power electronic converters as the grid connection interface. To analyze the synchronization stability domain of a high-proportion new energy power system, this invention first establishes a model as follows: Figure 2 The VSC access AC system model shown is illustrated. Figure 2 In this model, the VSC uses an average value model and is connected to the AC power grid after being stepped up by a transformer. The AC power grid is represented using the Thevenin equivalent circuit. Where i c For input current; u r u s and u g These represent the new energy generator terminal voltage, AC bus voltage, and AC grid equivalent power source electromotive force, respectively; L c L r and L g These are the equivalent inductance of the filter, the grid-connected inductance, and the equivalent inductance of the AC power grid, respectively.

[0076] The voltage source converter (VSC) of this invention employs grid voltage orientation based on a phase-locked loop (PLL), and the control loop topology is as follows: Figure 3 As shown, its control system equations are:

[0077]

[0078] In the formula, θ pll k is the phase-locked angle of the PLL. p_pll k i_pll For the PI parameters of the PLL, u r q This represents the q-axis component of the terminal voltage of the new energy source.

[0079] Secondly, determine the voltage analysis model of the VSC grid-connected system that takes into account the dynamics of the phase-locked loop.

[0080] To further simplify the analysis process, considering that the dynamic process of the inner current loop is much faster than other control links, the following assumptions can be made: i c d =i c d* i c q =i c q* Furthermore, due to the slow dynamic process of the outer control loop, this paper ignores the dynamics of the outer control loop. The new energy generator terminal voltage u is written in the dq coordinate system. r The equation is:

[0081]

[0082] In the formula, L ∑ =L r +L g ;u g d u g q These are the d-axis and q-axis components of the electromotive force of the equivalent source of the AC power grid, respectively; ω pll The angular frequency of the PLL. The Thevenin equivalent circuit of the VSC grid-connected system is as follows: Figure 4 As shown.

[0083] For the renewable energy generator side, during steady-state operation of the VSC grid-connected system, the active power P injected into the power system by the renewable energy grid-side VSC is in a stable operating state. r 1.0 pu, reactive power Q r The value is 0. Based on the current assumption of stage I, equation (5) can be simplified to:

[0084]

[0085] In the formula, u g0 d u g0 q These are the d-axis and q-axis components of the equivalent source electromotive force of the AC power grid under rated operating conditions; u r0 d u r0 q These are the d-axis and q-axis components of the new energy vehicle terminal voltage, respectively.

[0086] Under rated operating conditions, the voltage amplitude U at the generator terminals of the new energy source is... r0 It can be represented as:

[0087]

[0088] In the formula, δ0 represents the d-axis component of the new energy generator terminal voltage and the equivalent electromotive force U of the AC power grid under rated operating conditions. g The angle between them.

[0089] After a large disturbance fault occurs in the system, the VSC grid-connected system will experience overvoltage in the initial period after the fault is cleared due to short-term reactive power surplus. Ignoring the dynamics of the inner current loop and the outer power loop, equation (5) can be simplified to:

[0090]

[0091] Then at any time t, the voltage amplitude U at the new energy generator terminal is... r It can be represented as:

[0092]

[0093] Among them, U r (t) represents the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll (t) represents the phase-locked angle of the phase-locked loop at time t; L ∑ This is the equivalent reactance from the new energy generator to the infinite power supply.

[0094] From the above equation, it can be seen that δ after large disturbance removal pll The voltage difference ΔU between the VSC grid-connected system after disturbance clearance and during steady-state operation is related to factors such as the degree of disturbance, the time of disturbance clearance, and line impedance. r It can be represented as:

[0095] ΔU r =U r-U r0 (10)

[0096] To further determine the aforementioned voltage difference ΔU r The maximum value and its variation with δ pll The changing trend of voltage, i.e., the maximum voltage that the new energy generator terminal may withstand after a large disturbance, is the subject of this invention. An intermediate variable ΔM is introduced. r , can be represented as:

[0097]

[0098] Calculate the intermediate variable ΔM r The derivative of can be expressed as:

[0099]

[0100] From the above equation, we can see that the intermediate variable ΔM r With voltage difference ΔU r Since they have the same monotonicity, the intermediate variable ΔM r The maximum point is also the voltage difference ΔU r The maximum point of δ. pll When the angle is -180°, that is, the d-axis component of the new energy generator terminal voltage and the equivalent power source electromotive force U of the AC grid. g When the directions are opposite, the intermediate variable ΔM r The maximum value is reached when the voltage U at the new energy generator terminal reaches its maximum potential withstand value. r_max , can be represented as:

[0101]

[0102] Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid. ∑ The equivalent reactance from the new energy generator to the infinite power supply.

[0103] For the AC bus, first transform its voltage to the dq coordinate system of the VSC grid-connected system, and then determine the amplitude U of the AC bus voltage during steady-state operation. s0 for:

[0104]

[0105] The amplitude U of the AC bus voltage at any time t after the large disturbance is cleared. s for:

[0106]

[0107] Among them, U gThe electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll (t) represents the phase-locked angle of the phase-locked loop at time t; L ∑ The equivalent reactance from the new energy generator to the infinite power supply; U s (t) represents the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; L represents the d-axis component of the AC bus voltage at time t. g This is the equivalent reactance from the AC bus to the infinite power source.

[0108] The voltage difference ΔU between the AC bus after disturbance removal and during steady-state operation s It can be represented as:

[0109] ΔU s =U s -U s0 (16)

[0110] An intermediate variable ΔM, similar to that in equation (11), can be introduced. s Used to measure voltage difference ΔU s Maximum value and its variation with δ pll The changing trend of δ. pll When the angle is -180°, that is, the d-axis component of the new energy generator terminal voltage and the equivalent power source electromotive force U of the AC grid. g When the directions are opposite, the intermediate variable ΔM s When the maximum value is reached, the AC bus reaches the maximum voltage U that it can withstand. s_max , can be represented as:

[0111]

[0112] Among them, U s_max U represents the maximum AC bus voltage. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid. g This is the equivalent reactance from the AC bus to the infinite power source.

[0113] In step 103, when the maximum value of the new energy generator terminal voltage is greater than the preset generator terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value, it is determined that there is an overvoltage risk.

[0114] The dynamic processes of the new energy generator terminal voltage and AC bus voltage after a large disturbance fault are similar, and they both reach voltage extreme values ​​simultaneously. Their values ​​are similar to δ during the dynamic process after the fault is cleared. pll It is related to factors such as the electrical distance between it and the AC power grid.

[0115] If the voltage at any point between the renewable energy generator terminal voltage and the AC bus voltage exceeds the renewable energy overvoltage protection setting or the AC equipment insulation coordination requirements (e.g., the instantaneous peak value of the generator terminal voltage exceeds 1.3 pu), then an overvoltage is said to have occurred in the high-proportion renewable energy power system. Specifically, in this invention, when the maximum value of the renewable energy generator terminal voltage is greater than the preset generator terminal voltage peak value of 1.3 pu or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value of 1.3 pu, an overvoltage risk can be determined.

[0116] In step 104, the overvoltage risk coefficient of the new energy generator terminal is calculated based on the voltage amplitude of the new energy generator terminal, or the overvoltage risk coefficient of the AC bus is calculated based on the voltage amplitude of the AC bus.

[0117] Preferably, the step of calculating the overvoltage risk coefficient at the new energy generator terminal based on the voltage amplitude at the new energy generator terminal or calculating the overvoltage risk coefficient at the AC bus based on the voltage amplitude at the AC bus includes:

[0118]

[0119]

[0120] Where, k r For terminal overvoltage risk factor; k s For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

[0121] In step 105, a risk assessment is conducted based on the overvoltage risk coefficient of the new energy generator terminal or the overvoltage risk coefficient of the AC bus, and the assessment result is determined.

[0122] Preferably, the risk assessment is conducted based on the overvoltage risk coefficient at the new energy generator terminal or the overvoltage risk coefficient at the AC bus, and the assessment result is determined, including:

[0123] If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal.

[0124] If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal;

[0125] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk.

[0126] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

[0127] In this invention, when an overvoltage risk is determined to exist, a risk coefficient is calculated, and a risk assessment is performed based on the risk coefficient.

[0128] Specifically, the risk coefficient is calculated using the following formula, including:

[0129]

[0130]

[0131] Where, k r For terminal overvoltage risk factor; k s For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

[0132] If the overvoltage risk coefficient of the new energy generator terminal is equal to 0, the assessment result is determined to be critical risk of the new energy generator terminal; if the overvoltage risk coefficient of the new energy generator terminal is greater than 0, the assessment result is determined to be risk of the new energy generator terminal; if the overvoltage risk coefficient of the AC bus is equal to 0, the assessment result is determined to be critical risk of the AC bus; if the overvoltage risk coefficient of the AC bus is equal to 0, the assessment result is determined to be risk of the AC bus.

[0133] This invention considers the impact of the dynamic phase-locked loop of new energy power sources on the system voltage, and obtains accurate overvoltage calculation results for new energy generator terminals and AC equipment in high-proportion new energy power systems. Based on the overvoltage calculation results, risk assessment is carried out, which can provide strong support for the safety and stability analysis and control of high-proportion new energy power systems.

[0134] Figure 5 This is a schematic diagram of the overvoltage risk calculation system 500 for a new energy power system considering phase-locked loop dynamics according to an embodiment of the present invention. Figure 5 As shown, the overvoltage risk calculation system 500 for new energy power systems that takes into account phase-locked loop dynamics provided in this embodiment of the invention includes: a voltage amplitude determination unit 501, a voltage maximum value determination unit 502, a judgment unit 503, a coefficient determination unit 504, and an evaluation unit 505.

[0135] Preferably, the voltage amplitude determination unit 501 is used to determine the voltage amplitude of the new energy generator terminal and the AC bus at any time after the fault is cleared.

[0136] Preferably, the voltage amplitude determination unit 501 determines the voltage amplitude at the new energy generator terminal and the AC bus at any time after the fault is cleared, including:

[0137]

[0138]

[0139] Among them, U r (t) represents the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the AC power grid is the equivalent source electromotive force; ω pll (t) represents the angular frequency of the phase-locked loop at time t; δ pll (t) represents the phase-locked angle of the phase-locked loop at time t; L ∑ The equivalent reactance from the new energy generator to the infinite power supply; U s (t) represents the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; L represents the d-axis component of the AC bus voltage at time t. g This is the equivalent reactance from the AC bus to the infinite power source.

[0140] Preferably, the voltage maximum value determination unit 502 is used to determine the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal and the AC bus can withstand, respectively.

[0141] Preferably, the voltage maximum value determination unit 502 determines the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal equipment and the AC bus can withstand, respectively, including:

[0142]

[0143]

[0144] Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the AC power grid is the equivalent source electromotive force; ω g L is the angular frequency of the AC power grid. Σ The equivalent reactance from the new energy generator to the infinite power supply; L g This is the equivalent reactance from the AC bus to the infinite power source.

[0145] Preferably, the judgment unit 503 is used to determine that there is an overvoltage risk when the maximum value of the new energy terminal voltage is greater than the preset terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value.

[0146] Preferably, the coefficient determination unit 504 is used to calculate the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or to calculate the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus.

[0147] Preferably, the coefficient determining unit 504 calculates the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or calculates the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus, including:

[0148]

[0149]

[0150] Where, k r For terminal overvoltage risk factor; k s For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

[0151] Preferably, the evaluation unit 505 is used to perform risk assessment based on the new energy terminal overvoltage risk coefficient or the AC bus overvoltage risk coefficient, and determine the evaluation result.

[0152] Preferably, the evaluation unit 505 performs a risk assessment based on the new energy terminal overvoltage risk coefficient or the AC bus overvoltage risk coefficient, and determines the assessment result, including:

[0153] If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal.

[0154] If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal;

[0155] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk.

[0156] If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

[0157] The overvoltage risk calculation system 500 for new energy power systems that takes into account phase-locked loop dynamics in an embodiment of the present invention corresponds to the overvoltage risk calculation method 100 for new energy power systems that takes into account phase-locked loop dynamics in another embodiment of the present invention, and will not be described again here.

[0158] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any one of the steps in a method for calculating overvoltage risk in a new energy power system taking into account phase-locked loop dynamics.

[0159] According to another aspect of the present invention, an electronic device is provided, comprising: the above-described computer-readable storage medium; and one or more processors for executing a program in the computer-readable storage medium.

[0160] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0161] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0162] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0163] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0164] 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.

[0165] 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.

[0166] 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 calculating overvoltage risk in a new energy power system considering phase-locked loop dynamics, characterized in that, The method includes: Determine the voltage amplitude at the new energy generator terminal and the AC bus at any time after the fault is cleared; Determine the maximum voltage that the new energy generator terminal and the AC bus can withstand, respectively. When the maximum value of the new energy generator terminal voltage is greater than the preset generator terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value, it is determined that there is an overvoltage risk. Calculate the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal, or calculate the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus. Risk assessment is conducted based on the risk coefficient of overvoltage at the new energy generator terminal or the risk coefficient of overvoltage at the AC bus, and the assessment result is determined. Specifically, determining the voltage amplitude at the new energy generator terminal and the AC bus at any given moment after the fault is cleared includes: ， ， in, Let be the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the equivalent power source of the AC power grid; Let be the angular frequency of the phase-locked loop at time t; Let be the phase-locked angle of the phase-locked loop at time t; The equivalent reactance from the new energy generator to the infinite power supply; Let be the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; Let be the d-axis component of the AC bus voltage at time t; This is the equivalent reactance from the AC bus to the infinite power source.

2. The method according to claim 1, characterized in that, The determination of the maximum new energy generator terminal voltage and the maximum AC bus voltage that the new energy generator terminal equipment and AC bus can withstand includes: ， ， Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the equivalent power source of the AC power grid; The angular frequency of the AC power grid; The equivalent reactance from the new energy generator to the infinite power supply; This is the equivalent reactance from the AC bus to the infinite power source.

3. The method according to claim 1, characterized in that, The calculation of the overvoltage risk coefficient at the new energy generator terminal based on the voltage amplitude at the new energy generator terminal or the calculation of the overvoltage risk coefficient at the AC bus based on the voltage amplitude at the AC bus includes: ， ， in, The risk factor for terminal overvoltage; For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

4. The method according to claim 1, characterized in that, A risk assessment is conducted based on the aforementioned overvoltage risk coefficient at the new energy generator terminal or the overvoltage risk coefficient at the AC bus, and the assessment results are determined, including: If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal. If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal. If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk. If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

5. A new energy power system overvoltage risk calculation system considering phase-locked loop dynamics, characterized in that, The system includes: The voltage amplitude determination unit is used to determine the voltage amplitude of the new energy generator terminal and the AC bus at any time after the fault is cleared. The maximum voltage determination unit is used to determine the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal and the AC bus can withstand, respectively. The judgment unit is used to determine that there is an overvoltage risk when the maximum value of the new energy terminal voltage is greater than the preset terminal voltage peak value or the maximum value of the AC bus voltage is greater than the preset AC bus voltage peak value. The coefficient determination unit is used to calculate the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or to calculate the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus. The assessment unit is used to conduct risk assessment based on the overvoltage risk coefficient of the new energy generator terminal or the overvoltage risk coefficient of the AC bus, and determine the assessment result. The voltage amplitude determination unit determines the voltage amplitude at the new energy generator terminal and the AC bus at any given moment after the fault is cleared, including: ， ， in, Let be the voltage amplitude at the generator terminal of the new energy source at time t; Let be the q-axis component of the new energy generator terminal voltage at time t; U represents the d-axis component of the new energy generator terminal voltage at time t; g The electromotive force of the equivalent power source of the AC power grid; Let be the angular frequency of the phase-locked loop at time t; Let be the phase-locked angle of the phase-locked loop at time t; The equivalent reactance from the new energy generator to the infinite power supply; Let be the amplitude of the AC bus voltage at time t; Let be the q-axis component of the AC bus voltage at time t; Let be the d-axis component of the AC bus voltage at time t; This is the equivalent reactance from the AC bus to the infinite power source.

6. The system according to claim 5, characterized in that, The voltage maximum value determination unit determines the maximum voltage of the new energy generator terminal and the maximum voltage of the AC bus that the new energy generator terminal equipment and the AC bus can withstand, respectively, including: ， ， Among them, U r_max U represents the maximum voltage at the generator terminal of the new energy source. s_max U represents the maximum AC bus voltage. g The electromotive force of the equivalent power source of the AC power grid; The angular frequency of the AC power grid; The equivalent reactance from the new energy generator to the infinite power supply; This is the equivalent reactance from the AC bus to the infinite power source.

7. The system according to claim 5, characterized in that, The coefficient determination unit calculates the overvoltage risk coefficient of the new energy generator terminal based on the voltage amplitude of the new energy generator terminal or the overvoltage risk coefficient of the AC bus based on the voltage amplitude of the AC bus, including: ， ， in, The risk factor for terminal overvoltage; For AC bus overvoltage risk factor; U r For the voltage amplitude at the new energy generator terminal; U s This represents the amplitude of the AC bus voltage.

8. The system according to claim 5, characterized in that, The assessment unit performs a risk assessment based on the new energy generator terminal overvoltage risk coefficient or the AC bus overvoltage risk coefficient, and determines the assessment result, including: If the overvoltage risk coefficient at the new energy generator terminal is equal to 0, then the assessment result is determined to be the critical risk at the new energy generator terminal. If the overvoltage risk coefficient at the new energy generator terminal is greater than 0, then the assessment result is determined to be that there is a risk at the new energy generator terminal. If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be the AC bus critical risk. If the AC bus overvoltage risk coefficient is equal to 0, then the assessment result is determined to be that there is a risk to the AC bus.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-4.

10. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 9; as well as One or more processors for executing a program in the computer-readable storage medium.

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