Damping characteristic evaluation method, device and system of power system

Abstract

The invention relates to a damping characteristic evaluation method, device and system of a power system, and relates to the technical field of power systems. The method comprises the steps of obtaining power data and angular frequency data of a generator set in a preset time period, generating a first variable quantity curve according to the power data, determining first characteristic information of the first variable quantity curve, generating a second variable quantity curve according to the angular frequency data, and determining second characteristic information of the second variable quantity curve, determining a power variable quantity matrix according to the first characteristic information, determining an angular frequency variable quantity matrix according to the second characteristic information, determining an equivalent admittance coefficient according to the power variable quantity matrix and the angular frequency variable quantity matrix, and evaluating the damping characteristic of the generator set by using the equivalent admittance coefficient to obtain an evaluation result. According to the scheme, the accuracy of evaluating the damping characteristics is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of power systems, and particularly relates to a damping characteristic evaluation method, device and system of a power system. BACKGROUND

[0002] In the related art, the damping of a power system is an important parameter for transient stability calculation in a system oscillation process. The system damping can effectively suppress low-frequency oscillation after power grid disturbance. Too large or too small damping coefficients are both unfavorable for the system to recover from the oscillation process to a steady state. Therefore, it is necessary to evaluate the damping coefficient of the power system so as to control the damping. However, the existing damping characteristic evaluation method has poor accuracy and cannot meet the actual demand. SUMMARY

[0003] To overcome the problems in the related art, the present disclosure provides a damping characteristic evaluation method, device and system of a power system.

[0004] According to a first aspect of the embodiments of the present disclosure, a damping characteristic evaluation method of a power system is provided, comprising:

[0005] obtaining power data and angular frequency data of a generator set in a preset time period; the generator set is a generator set in the power system;

[0006] generating a first change amount curve according to the power data, determining first characteristic information of the first change amount curve, generating a second change amount curve according to the angular frequency data, and determining second characteristic information of the second change amount curve;

[0007] determining a power change amount matrix according to the first characteristic information, and determining an angular frequency change amount matrix according to the second characteristic information;

[0008] determining an equivalent admittance coefficient according to the power change amount matrix and the angular frequency change amount matrix;

[0009] evaluating the damping characteristic of the generator set by using the equivalent admittance coefficient to obtain an evaluation result.

[0010] In some embodiments of the present disclosure, the preset time period includes N time nodes, each of the N time nodes corresponds to a power value and an angular frequency value; the first change amount curve is generated according to the power data, comprising:

[0011] determining a difference between each power value and a preset steady-state power value according to the power value corresponding to each of the N time nodes, to obtain N power change amounts; N is an integer greater than 1;

[0012] According to the N power variation amounts and the time nodes corresponding to the N power variation amounts, a first variation curve is generated; the first variation curve comprises a corresponding relationship between the N power variation amounts and the time nodes;

[0013] The second characteristic information of the second variation curve is determined, comprising:

[0014] According to the N time nodes each corresponding to an angular frequency value, a difference between each angular frequency value and a preset steady-state angular frequency value is determined, to obtain N angular frequency variation amounts;

[0015] According to the N angular frequency variation amounts and the time nodes corresponding to the N angular frequency variation amounts, a second variation curve is generated; the second variation curve comprises a corresponding relationship between the N angular frequency variation amounts and the time nodes.

[0016] In some embodiments of the present disclosure, the determination of the power variation matrix according to the first characteristic information comprises:

[0017] The power data is fitted by using the first characteristic information, to obtain the power variation matrix;

[0018] The determination of the angular frequency variation matrix according to the second characteristic information comprises:

[0019] The angular frequency data is fitted by using the second characteristic information, to obtain the angular frequency variation matrix.

[0020] In some embodiments of the present disclosure, the determination of the equivalent admittance coefficient according to the power variation matrix and the angular frequency variation matrix comprises:

[0021] The ratio of the power variation matrix to the angular frequency variation matrix is determined, to obtain an equivalent admittance matrix;

[0022] The equivalent admittance matrix is solved, to obtain the equivalent admittance coefficient.

[0023] In some embodiments of the present disclosure, before the power data and the angular frequency data of the generator set in a preset time period are acquired, the method further comprises:

[0024] It is determined whether the power system has low-frequency oscillation;

[0025] In the case that the power system has low-frequency oscillation, the step of acquiring the power data and the angular frequency data of the generator set in a preset time period is performed.

[0026] In some embodiments of the present disclosure, the damping characteristic comprises a damping contribution degree; the generator set is multiple; the damping characteristic of the generator set is evaluated by using the equivalent admittance coefficient, and evaluation results are obtained, comprising:

[0027] For each of the multiple generator sets, the damping contribution degree of the generator set is determined according to the size of the equivalent admittance coefficient corresponding to the generator set; and / or,

[0028] For multiple equivalent admittance coefficients under the same low-frequency oscillation, the average value of the multiple equivalent admittance coefficients is determined, and the damping contribution degrees of the multiple generator sets under different power system operating conditions are determined according to the average values corresponding to the multiple low-frequency oscillations respectively; the multiple equivalent admittance coefficients correspond to the multiple generator sets one by one.

[0029] According to a second aspect of the embodiments of the present disclosure, a damping characteristic evaluation device of a power system is provided, comprising:

[0030] An acquisition unit is configured to acquire power data and angular frequency data within a preset time period of a generator set; the generator set is a generator set in the power system;

[0031] A first determination unit is configured to generate a first change amount curve according to the power data, determine first feature information of the first change amount curve, generate a second change amount curve according to the angular frequency data, and determine second feature information of the second change amount curve;

[0032] A second determination unit is configured to determine a power change amount matrix according to the first feature information, and determine an angular frequency change amount matrix according to the second feature information;

[0033] A third determination unit is configured to determine an equivalent admittance coefficient according to the power change amount matrix and the angular frequency change amount matrix;

[0034] An evaluation unit is configured to evaluate the damping characteristic of the generator set by using the equivalent admittance coefficient, and obtain evaluation results.

[0035] According to a third aspect of the embodiments of the present disclosure, an electronic device comprises a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the computer program, the method of any one of the first aspect is implemented.

[0036] According to a fourth aspect of the embodiments of the present disclosure, a computer readable storage medium is provided, and a computer program is stored on the computer readable storage medium, and when the computer program is executed by a processor, the method of any one of the first aspect is implemented.

[0037] According to a fifth aspect of embodiments of the present disclosure, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the method according to any one of the first aspect.

[0038] The technical solution provided by the embodiments of the present disclosure can have the following beneficial effects: power data and angular frequency data of the generator set in a preset time period are obtained, a first change amount curve is generated according to the power data, first feature information of the first change amount curve is determined, a second change amount curve is generated according to the angular frequency data, second feature information of the second change amount curve is determined, a power change amount matrix is determined according to the first feature information, an angular frequency change amount matrix is determined according to the second feature information, an equivalent admittance coefficient is determined according to the power change amount matrix and the angular frequency change amount matrix, the equivalent admittance coefficient is used to evaluate the damping characteristic of the generator set, and an evaluation result is obtained. By equivalent damping of the generator set to admittance in electric quantity, the equivalent admittance coefficient is used to evaluate the damping characteristic, and the accuracy of evaluating the damping characteristic is improved.

[0039] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present disclosure and serve to explain the principles of the present disclosure together with the description.

[0041] Figure 1 is a flowchart of a damping characteristic evaluation method of a power system according to an exemplary embodiment.

[0042] Figure 2 is a Phillips-Heffron model structure diagram according to an exemplary embodiment.

[0043] Figure 3 is a circuit diagram of an SG according to an exemplary embodiment.

[0044] Figure 4 is a VC-VSC topology structure diagram according to an exemplary embodiment.

[0045] Figure 5 is a CC-VSC topology structure diagram according to an exemplary embodiment.

[0046] Figure 6 is a block diagram of a damping characteristic evaluation device of a power system according to an exemplary embodiment.

[0047] Figure 7 is a block diagram of a device for damping characteristic evaluation of a power system according to an exemplary embodiment. DETAILED DESCRIPTION

[0048] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to various alternative forms of the exemplary embodiments. It is to be understood that the following description is not intended to limit the exemplary embodiments to a single preferred embodiment. On the contrary, the exemplary embodiments are described with a sufficient degree of uniqueness to convey the essence of the present disclosure to those who are skilled in this art.

[0049] The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0050] It should be understood that although the terms first, second, third, etc. can be used herein to describe various information, these terms are merely used to distinguish one piece of information from another. For example, a first piece of information can also be referred to as a second piece of information, and similarly, a second piece of information can also be referred to as a first piece of information without departing from the scope of the present disclosure. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon" or "in response to determining".

[0051] In addition, the steps shown in various forms in the present disclosure can be reordered, added or deleted. For example, the steps described in the present disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved, and the present disclosure is not limited herein.

[0052] In the related art, the damping of the power system is an important parameter for transient stability calculation in the system oscillation process. The system damping can effectively suppress the low-frequency oscillation after the power grid disturbance. However, too large or too small damping coefficient is not conducive to the system to recover from the oscillation process to the steady state. Therefore, it is necessary to evaluate the damping coefficient of the power system, so as to control the damping. However, the existing damping characteristic evaluation method has poor accuracy and is difficult to meet the actual demand.

[0053] To solve the above problems, the present disclosure provides a damping characteristic evaluation method, device and system of a power system, which obtains power data and angular frequency data of a generator set within a preset time period, generates a first change amount curve according to the power data, determines first characteristic information of the first change amount curve, generates a second change amount curve according to the angular frequency data, determines second characteristic information of the second change amount curve, determines a power change amount matrix according to the first characteristic information, determines an angular frequency change amount matrix according to the second characteristic information, determines an equivalent admittance coefficient according to the power change amount matrix and the angular frequency change amount matrix, evaluates the damping characteristic of the generator set by using the equivalent admittance coefficient, and obtains an evaluation result. By equivalent the damping of the generator set to the admittance in the electric quantity, the equivalent admittance coefficient is used to evaluate the damping characteristic, and the accuracy of evaluating the damping characteristic is improved.

[0054] At present, the proportion of power electronic devices in new energy power generation systems is increasing, which contains different types of voltage source converters (VSC). Such multi-machine systems are more prone to various oscillation phenomena. Converting the multi-machine new energy power system into a P / ω "admittance" circuit model is conducive to analyzing the system parameters under oscillation.

[0055] The Phillips-Heffron model of the linearized SG rotor motion equation is shown in Figure 2 , which can clearly and intuitively reflect the small signal dynamic relationship between torque and angular frequency, and considers the SG output torque and angular frequency response under oscillation excitation of input torque ΔT in and angular speed disturbance Δω c .

[0056] In order to convert the SG into a unified P / ω "admittance" circuit model, two admittances are defined according to the Phillips-Heffron model. The first admittance Y a (s) is the inverse of the open-loop transfer function of input torque ΔT in to angular frequency Δω; the second admittance Y b (s) is the open-loop transfer function of angular frequency increment (Δω-Δω c ) to torque ΔT, which is specifically shown in the following formula:

[0057]

[0058] The model of Figure 2 is represented by equivalent circuit elements and packaged to obtain a unified circuit model containing torque source ΔT in , angular frequency disturbance source Δωc and first and second admittances, as shown in Figure 3 . Among them, the torque change amount ΔT=ΔT e +ΔTD , Y a (s) = sK J -G GOV (s), Y a on the potential of Δω, Y b (s) = K S / s + K D where K J represents the inertia coefficient, K D represents the damping torque coefficient. ΔT D is the damping torque increment, ΔT e is the synchronous torque increment, K S is the synchronous torque coefficient, G GOV (s) is the transfer function of the SG governor. This model can comprehensively describe the response of ΔT in and Δω c under the excitation of ΔT c and Δω in , and satisfies the following formula:

[0059]

[0060] The relationship between the torque change and the power change is determined by the following formula:

[0061] ΔP = ΔTω

[0062] The SG circuit model can be converted into the relationship between the power change ΔP and the angular frequency change Δω.

[0063] The topology of the VC-VSC is shown in Figure 4 , and the topology of the CC-VSC is shown in Figure 5 Due to the differences in the power supply interface on the AC side, the energy supply on the DC side, the load characteristics on the DC side, and the control structure of the VSC, there are various types.

[0064] For VSCs using different control strategies, the low-frequency dynamics mainly include DC capacitor dynamics, phase-locked loop dynamics, virtual inertia, and damping control. The VSC is modeled as the same circuit model. For both VC-VSC and CC-VSC, the response under the disturbance of Δω c and the input of ΔT in may be different, and it is necessary to distinguish the response under the disturbance of these two. Therefore, based on the small signal block diagram model and the model parameters of the typical control scheme, the block diagram model is improved by considering the influence of the disturbance of Δω c , and finally the block diagram model is converted into a unified circuit model. The modeling framework is shown in Figure 5 .

[0065] The difference is that K SIt is important to note that the transmission reactance of a VC-VSC is the sum of the filter reactance and the line reactance, while the transmission reactance of a CC-VSC only contains the line reactance. Based on the above framework, the VSC is transformed into a P / ω "admittance" circuit model as the SG.

[0066] In the conventional induction generator effect, the negative damping of the whole system is provided by r r / s, where s is the slip, and in which ω r is the electrical angular speed of the rotor. At subsynchronous frequencies, there is always s < 0, i.e. the equivalent resistance of the rotor is negative.

[0067] s= ω omega-omega r

[0068] ω

[0069] When a wind farm equipped with a large number of doubly-fed induction generators encounters subsynchronous resonance problems, one factor that cannot be ignored is that the converters in these wind turbines actually contribute to the negative damping phenomenon, especially the proportional gain coefficient Kp of the current control in the machine-side converter, which is directly related to the generation of the equivalent negative damping of the system, and thus becomes the essential reason why such wind farms are prone to subsynchronous resonance problems. In short, in the environment of intensive deployment of doubly-fed wind turbines, their built-in converters inadvertently provide conditions for the occurrence of subsynchronous resonance problems through the action of the Kp value.

[0070] Although the basic structure of the power grid has remained relatively stable in recent years, the fine-tuning of the operation mode has limited impact on the overall grid-side impedance, resulting in a relatively fixed high-risk area of impedance resonance. In contrast, the impedance characteristics of the source side (source side) are complex and diverse due to the operating conditions of various generator types, the scale of access to the power grid, and the setting of different control strategies and parameters, which makes it a great challenge to accurately assess whether the source-side impedance will cause negative damping effects. In particular, the impedance characteristics of doubly-fed wind generators are deeply affected by their manufacturers, specific models, operating capacity, and control mechanisms, and even wind turbines of the same model will exhibit different impedance behaviors in different operating states. Typically, the impedance of a doubly-fed wind turbine rises rapidly by more than 90 degrees from 1 Hz to 20 Hz frequency range, indicating a negative damping phenomenon; while the impedance phase growth of direct-drive wind turbines or photovoltaic power systems is more gradual, usually maintaining within 90 degrees, maintaining positive damping characteristics.

[0071] In the scenario of multiple generators operating in parallel, their collective impedance is approximately equivalent to the impedance of a single device in the frequency domain. When different types of generators are connected in parallel, the final impedance amplitude and phase angle are the result of the combination of the impedance characteristics of each unit, determined by the impedance size, phase angle, and online operation ratio of each unit. Parallel operation usually reduces the amplitude of the total impedance, while the phase angle falls within the range of the phase angles of each individual impedance. It is worth noting that those generator units with smaller impedance amplitudes and larger phase differences have a more significant "pull" effect on the overall impedance characteristics. Therefore, if the number of grid-connected doubly-fed wind turbines increases and these wind turbines exhibit unfavorable phase characteristics, it will be increasingly difficult to optimize the aggregated impedance phase, and may exacerbate the negative damping tendency of the overall system.

[0072] Figure 1 is a flow chart of a method for evaluating the damping characteristics of a power system according to an exemplary embodiment, as shown in Figure 1 It should be noted that the method for evaluating the damping characteristics of a power system according to the embodiments of the present disclosure is applied to a device for evaluating the damping characteristics of a power system. As shown in Figure 1 The method can include the following steps:

[0073] Step 101: Obtain power data and angular frequency data of the generator set within a preset time period.

[0074] In the embodiments of the present disclosure, the generator set can be one or more.

[0075] It should be noted that the power data can include the power values of the generator set at different time nodes within the preset time period, and the angular frequency data can include the angular frequencies of the generator set at different time nodes within the preset time period.

[0076] In some embodiments of the present disclosure, before step 101, the method can further include the following steps: determining whether the power system has low-frequency oscillation, and executing step 101 if the power system has low-frequency oscillation.

[0077] It should be noted that the damping characteristics of the generator set are evaluated by the power and angular frequency in the case of low-frequency oscillation in the power system, and the system damping is adjusted according to the evaluation result, so as to reduce the low-frequency oscillation. Compared with obtaining the power data and angular frequency data of the generator set within a preset time period in real time, the calculation resource is saved.

[0078] In one embodiment, whether the power system has low-frequency oscillation can be determined by the steady-state data and oscillation data of each electrical quantity in the power system.

[0079] In one embodiment, whether the power system has low-frequency oscillation can be determined by the steady-state data and oscillation data of each electrical quantity in the power system.

[0080] Step 102: Generate a first change curve based on the power data, determine the first characteristic information of the first change curve, generate a second change curve based on the angular frequency data, and determine the second characteristic information of the second change curve.

[0081] In one embodiment, the first change curve is used to reflect the mapping relationship between the generator's power and the time node, and the second change curve is used to reflect the mapping relationship between the generator's angular frequency and the time node.

[0082] The first feature information may include the frequency, amplitude, phase, and time interval of the first change curve, and the second feature information may include the frequency, amplitude, phase, and time interval of the second change curve.

[0083] In some embodiments of this disclosure, the preset time period includes N time nodes, and each time node within the N time nodes corresponds to a power value and an angular frequency value. Generating a first change curve based on the power data may specifically include:

[0084] Step a1: Based on the power values ​​corresponding to the N time nodes, determine the difference between each power value and the preset steady-state power value to obtain N power change quantities.

[0085] Where N is an integer greater than 1.

[0086] In one embodiment, the power change can be calculated using the following formula:

[0087] ΔP i =P i –P i,S

[0088] Among them, P i Let P be the power value corresponding to the i-th time node. i,S Let ΔP be the preset steady-state power value corresponding to the i-th time node. i This represents the power change at the i-th time node.

[0089] Step a2: Generate the first change curve based on the N power changes and the time nodes corresponding to the N power changes.

[0090] The first change curve includes the correspondence between N power changes and time points.

[0091] In one embodiment, the time point can be used as the horizontal axis and the power change as the vertical axis to generate the first change curve.

[0092] The second characteristic information for determining the second change curve may specifically include:

[0093] Step b1, according to the angular frequency value corresponding to each of the N time nodes, determine the difference between each angular frequency value and the preset steady-state angular frequency value, to obtain N angular frequency variation amounts.

[0094] In one embodiment, the angular frequency variation amount can be calculated by the following formula:

[0095] Δω i = ω i - ω i,S

[0096] Wherein, ω i is the angular frequency value corresponding to the i-th time node, ω i,S is the preset steady-state angular frequency value corresponding to the i-th time node, and Δω i is the angular frequency variation amount corresponding to the i-th time node.

[0097] Step b2, according to the N angular frequency variation amounts and the time nodes corresponding to the N angular frequency variation amounts, generate a second variation curve.

[0098] Wherein, the second variation curve includes the corresponding relationship between the N angular frequency variation amounts and time.

[0099] In one embodiment, the time nodes can be taken as the horizontal coordinates, and the angular frequency variation amounts can be taken as the vertical coordinates, to generate the second variation curve.

[0100] Step 103, determine a power variation amount matrix according to the first characteristic information, and determine an angular frequency variation amount matrix according to the second characteristic information.

[0101] In some embodiments of the present disclosure, determining the power variation amount matrix according to the first characteristic information can specifically include: fitting the power data by using the first characteristic information to obtain the power variation amount matrix.

[0102] In one embodiment, the power data is fitted by using the first characteristic information (i.e. the relevant modal information of the low-frequency oscillation of the power system) through the following formula:

[0103]

[0104] Wherein, ΔP a is a power component, a = 1, 2, …, n, and p is the fitting order; f m is the frequency; σ m is the damping factor; A m is the amplitude; θ m is the initial phase; and Δt is the time interval. According to the n power components, a power component matrix [ΔP] is obtained.

[0105] In some embodiments of the present disclosure, the angular frequency variation matrix is determined according to the second feature information, and specifically, the angular frequency variation matrix can be determined by fitting the angular frequency data according to the second feature information.

[0106] In one embodiment, the angular frequency data is fitted according to the following formula by using the second feature information (i.e., the relevant modal information of the low-frequency oscillation of the power system):

[0107]

[0108] wherein Δω a is the angular frequency component, a = 1, 2, …, n, and p is the fitting order; f m is the frequency; σ m is the damping factor; A m is the amplitude; θ m is the initial phase; and Δt is the time interval. The angular frequency component matrix [Δω] is obtained according to the n angular frequency components.

[0109] In step 104, the equivalent admittance coefficient is determined according to the power variation matrix and the angular frequency variation matrix.

[0110] In some embodiments of the present disclosure, step 104 can specifically include:

[0111] In step c1, the ratio of the power variation matrix to the angular frequency variation matrix is determined to obtain the equivalent admittance matrix.

[0112] In step c2, the equivalent admittance matrix is solved to obtain the equivalent admittance coefficient.

[0113] In one embodiment, the equivalent admittance matrix can be determined by the following formula:

[0114] [Y] = [Δω] / [ΔP]

[0115] wherein [Y] is the equivalent admittance matrix, [Δω] is the angular frequency component matrix, and [ΔP] is the power component matrix.

[0116] In one embodiment, after obtaining the equivalent admittance matrix [Y], [Y] can be solved to obtain the equivalent admittance coefficient.

[0117] In step 105, the damping characteristics of the generator set are evaluated by using the equivalent admittance coefficient to obtain an evaluation result.

[0118] It can be understood that the damping of the generator set is equivalent to the admittance in the electric quantity, and the equivalent admittance coefficient is used to evaluate the damping characteristics.

[0119] In some embodiments of the present disclosure, the damping characteristic includes a damping contribution degree, and the plurality of generator sets, and step 105 can specifically include the following steps:

[0120] Step d1, for each of the plurality of generator sets, determining the damping contribution degree of the generator set according to the size of the equivalent admittance coefficient corresponding to the generator set; and / or,

[0121] Step d2, for the plurality of equivalent admittance coefficients under the same low-frequency oscillation, determining the average value of the plurality of equivalent admittance coefficients, and determining the damping contribution degree of the plurality of generator sets under different power system operating conditions according to the average value corresponding to each of the plurality of low-frequency oscillations; the plurality of equivalent admittance coefficients correspond one-to-one to the plurality of generator sets.

[0122] In one embodiment, if the equivalent admittance coefficient is greater than 0, it represents that the unit provides positive damping contribution, if the equivalent admittance coefficient is less than 0, it represents that the unit provides negative damping contribution, and the greater the absolute value of the equivalent admittance coefficient, the more positive (negative) damping contribution is provided.

[0123] In another embodiment, since the damping of different generator sets in the same low-frequency oscillation is different, the overall damping of the power system also presents different states. Due to the difference in operating conditions and the difference in low-frequency oscillation types, the damping state of the system is also different, and by calculating the average damping of the plurality of generator sets in the same low-frequency oscillation, the disturbance of the system under different states can be analyzed. The influence degree of low-frequency oscillation under different power system operating conditions on the power system can be determined.

[0124] In some embodiments of the present disclosure, by accurately evaluating the damping coefficient of the system, the stability of the system can be better predicted and managed, and the risk of system instability caused by power grid failure can be reduced. Understanding the damping characteristic can develop more effective control strategies to improve the response capability of the wind storage combined power generation system or the grid-connected energy storage system under different load conditions. By increasing the damping capacity of the wind storage combined power generation system, its anti-interference and anti-fault capability can be improved, which helps to reduce system fluctuations and oscillations.

[0125] According to the damping characteristic evaluation of the power system provided in the embodiments of the present disclosure, power data and angular frequency data of a generator set in a preset time period are obtained, a first change amount curve is generated according to the power data, first characteristic information of the first change amount curve is determined, a second change amount curve is generated according to the angular frequency data, second characteristic information of the second change amount curve is determined, a power change amount matrix is determined according to the first characteristic information, an angular frequency change amount matrix is determined according to the second characteristic information, an equivalent admittance coefficient is determined according to the power change amount matrix and the angular frequency change amount matrix, the damping characteristic of the generator set is evaluated by using the equivalent admittance coefficient, and an evaluation result is obtained. By equivalent damping of the generator set to admittance in electric quantity, the equivalent admittance coefficient is used to evaluate the damping characteristic, and the accuracy of evaluating the damping characteristic is improved.

[0126] Figure 6 is a block diagram of a damping characteristic evaluation device of a power system according to an exemplary embodiment. Referring to Figure 6 The device includes an obtaining unit 601, a first determining unit 602, a second determining unit 603, a third determining unit 604, and an evaluation unit 605.

[0127] The obtaining unit 601 is configured to obtain power data and angular frequency data of a generator set in a preset time period; the generator set is a generator set in a power system.

[0128] The first determining unit 602 is configured to generate a first change amount curve according to the power data, determine first characteristic information of the first change amount curve, generate a second change amount curve according to the angular frequency data, and determine second characteristic information of the second change amount curve.

[0129] The second determining unit 603 is configured to determine a power change amount matrix according to the first characteristic information, and determine an angular frequency change amount matrix according to the second characteristic information.

[0130] The third determining unit 604 is configured to determine an equivalent admittance coefficient according to the power change amount matrix and the angular frequency change amount matrix.

[0131] The evaluation unit 605 is configured to evaluate the damping characteristic of the generator set by using the equivalent admittance coefficient, and obtain an evaluation result.

[0132] In some embodiments of the present disclosure, the preset time period includes N time nodes, each of the N time nodes corresponds to a power value and an angular frequency value, and the first determining unit 602 can be specifically configured to:

[0133] determine a difference between each power value and a preset steady-state power value according to the power value corresponding to each of the N time nodes, and obtain N power change amounts; N is an integer greater than 1.

[0134] According to the N power variation amounts and the time nodes corresponding to the N power variation amounts, a first variation curve is generated; the first variation curve includes the corresponding relationship between the N power variation amounts and the time nodes;

[0135] According to the angular frequency values corresponding to the N time nodes respectively, a difference between each angular frequency value and a preset steady-state angular frequency value is determined, to obtain N angular frequency variation amounts;

[0136] According to the N angular frequency variation amounts and the time nodes corresponding to the N angular frequency variation amounts, a second variation curve is generated; the second variation curve includes the corresponding relationship between the N angular frequency variation amounts and the time nodes.

[0137] In some embodiments of the present disclosure, the second determination unit 603 can be specifically configured to:

[0138] The power data is fitted by using the first feature information, to obtain a power variation amount matrix;

[0139] The angular frequency variation amount matrix is determined according to the second feature information, including:

[0140] The angular frequency data is fitted by using the second feature information, to obtain the angular frequency variation amount matrix.

[0141] In some embodiments of the present disclosure, the third determination unit 604 can be specifically configured to:

[0142] The ratio of the power variation amount matrix and the angular frequency variation amount matrix is determined, to obtain an equivalent admittance matrix;

[0143] The equivalent admittance matrix is solved, to obtain an equivalent admittance coefficient.

[0144] In some embodiments of the present disclosure, the device can further include:

[0145] The fourth determination unit is configured to determine whether the power system has low-frequency oscillation;

[0146] The execution unit is configured to, in the case that the power system has low-frequency oscillation, perform the step of acquiring the power data and the angular frequency data of the generator set within the preset time period.

[0147] In some embodiments of the present disclosure, the damping characteristic includes a damping contribution degree, the generator set has a plurality of generator sets, and the evaluation unit 605 can be specifically configured to:

[0148] For each of the plurality of generator sets, according to the size of the equivalent admittance coefficient corresponding to the generator set, the damping contribution degree of the generator set is determined; and / or,

[0149] The average value of the plurality of equivalent admittance coefficients under the same low-frequency oscillation is determined, and the damping contribution degree of the plurality of generator units under different power system operation conditions is determined according to the average values corresponding to the plurality of low-frequency oscillations respectively. The plurality of equivalent admittance coefficients correspond to the plurality of generator units one by one.

[0150] As to the apparatus in the above-mentioned embodiments, the specific manners in which the respective modules perform operations have been described in detail in the embodiments of the method, and thus will not be described in detail here.

[0151] The damping characteristic evaluation apparatus of the power system provided by the embodiments of the present disclosure obtains power data and angular frequency data of a generator unit in a preset time period, generates a first change amount curve according to the power data, determines first feature information of the first change amount curve, generates a second change amount curve according to the angular frequency data, determines second feature information of the second change amount curve, determines a power change amount matrix according to the first feature information, determines an angular frequency change amount matrix according to the second feature information, determines equivalent admittance coefficients according to the power change amount matrix and the angular frequency change amount matrix, evaluates the damping characteristic of the generator unit by using the equivalent admittance coefficients, and obtains an evaluation result. By equivalent the damping of the generator unit to the admittance in the electric quantity, the equivalent admittance coefficients are used to evaluate the damping characteristic, and the accuracy of the evaluation of the damping characteristic is improved.

[0152] Figure 7 is a block diagram of an apparatus for damping characteristic evaluation of a power system according to an example embodiment. For example, the apparatus 700 can be an electronic device such as a mobile phone, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, and the like.

[0153] Referring to Figure 7 , the apparatus 700 can include one or more of the following components: a processing component 702, a memory 704, a power supply 706, a multimedia component 708, an audio component 710, an input / output (I / O) interface 712, a sensor component 714, and a communication component 716.

[0154] The processing component 702 usually controls the overall operation of the apparatus 700, such as operations associated with displaying, making phone calls, data communications, camera operations and recording operations. The processing component 702 can include one or more processors 720 to execute instructions to complete all or part of the steps of the methods described above. In addition, the processing component 702 can include one or more modules to facilitate interaction between the processing component 702 and other components. For example, the processing component 702 can include a multimedia module to facilitate the interaction between the multimedia component 708 and the processing component 702.

[0155] The memory 704 is configured to store various types of data to support the operation of the device 700. Examples of these data include instructions for any application or method operating on the device 700, contact data, phonebook data, messages, pictures, videos, and the like. The memory 704 can be implemented by any type of volatile or nonvolatile storage devices or a combination thereof such as static random access memory (SRAM), electrically erasable programmable read only memory (EEPROM), erasable programmable read only memory (EPROM), programmable read only memory (PROM), read only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk.

[0156] The power component 706 provides power to the various components of the device 700. The power component 706 can include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power for the device 700.

[0157] The multimedia component 708 includes a screen providing an output interface between the device 700 and a user. In some embodiments, the screen can include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen can be implemented as a touch screen to receive an input signal from a user. The touch panel includes one or more touch sensors to sense a touch, a slide, and a gesture on the touch panel. The touch sensors can not only sense a boundary of a touching or sliding action, but also detect duration and pressure related to the touching or sliding action. In some embodiments, the multimedia component 708 includes a front camera and / or a rear camera. The front and / or rear camera can receive external multimedia data when the device 700 is in an operating mode, such as a shooting mode or a video mode. Each of the front and rear camera can be a fixed optical lens system or have a focal length and optical zoom capability.

[0158] The audio component 710 is configured to output and / or input an audio signal. For example, the audio component 710 includes a microphone (MIC) configured to receive an external audio signal when the device 700 is in an operating mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signal can be further stored in the memory 704 or transmitted via the communication component 716. In some embodiments, the audio component 710 also includes a speaker for outputting an audio signal.

[0159] The I / O interface 712 provides an interface between the processing component 702 and peripheral interface modules, which can be a keyboard, a click wheel, a button, and the like. The buttons can include, but are not limited to, a home button, a volume button, a start button, and a lock button.

[0160] The sensor component 714 includes one or more sensors for providing status assessments for various aspects of the device 700. For example, the sensor component 714 can detect an open / closed position of the device 700, relative positioning of components, such as a display and a keypad of the device 700, changes in position of the device 700 or a component of the device 700, presence or absence of user contact with the device 700, changes in orientation of the device 700 or acceleration / deceleration, and temperature changes of the device 700. The sensor component 714 can include proximity sensor(s) configured to detect presence of an object in proximity thereto without any physical contact. The sensor component 714 can also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor component 714 can also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

[0161] The communication component 716 is configured to facilitate wired or wireless communication between the device 700 and another device. The device 700 can access a wireless network based on a communication standard, such as WiFi, 2G, or 3G, or a combination thereof. In an exemplary embodiment, the communication component 716 receives a broadcast signal or broadcast related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 716 further includes a Near Field Communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on Radio Frequency Identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technology.

[0162] In an exemplary embodiment, the device 700 can be implemented using one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, or other electronic components, for performing the above-described methods.

[0163] In an exemplary embodiment, a non-transitory computer-readable storage medium, such as the memory 704 including instructions stored therein, is also provided. The instructions may, for example, be executable by the processor 720 of the device 700 to cause the device 700 to perform the above-described methods.

[0164] In an exemplary embodiment, a computer program product is also provided, including a computer program that, when executed by the processor 720 of the device 700, causes the device 700 to perform the above-described methods.

[0165] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0166] It is to be understood that the application is not limited to the precise construction hereinafter described and as shown in the attached drawings, and that various changes in the details and arrangements of parts can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims appended hereto.

Claims

1. A method for evaluating the damping characteristics of a power system, characterized in that, include: Acquire power and angular frequency data of the generator set within a preset time period; The generator set is the generator set in the power system; A first change curve is generated based on the power data, a first feature information of the first change curve is determined, and a second change curve is generated based on the angular frequency data, and a second feature information of the second change curve is determined. The power change matrix is ​​determined based on the first feature information, and the angular frequency change matrix is ​​determined based on the second feature information. The equivalent admittance coefficient is determined based on the power change matrix and the angular frequency change matrix. The damping characteristics of the generator set are evaluated using the equivalent admittance coefficient, and the evaluation results are obtained.

2. The method for evaluating the damping characteristics of a power system according to claim 1, characterized in that, The preset time period includes N time nodes, each of which corresponds to a power value and an angular frequency value; the step of generating a first change curve based on the power data includes: Based on the power values ​​corresponding to the N time points, the difference between each power value and the preset steady-state power value is determined to obtain N power change quantities; N is an integer greater than 1. The first change curve is generated based on the N power changes and the corresponding time points; the first change curve includes the correspondence between the N power changes and the time points. The second feature information for determining the second change curve includes: Based on the angular frequency values ​​corresponding to the N time points, the difference between each angular frequency value and the preset steady-state angular frequency value is determined, resulting in N angular frequency changes. The second change curve is generated based on the N angular frequency changes and the corresponding time points; the second change curve includes the correspondence between the N angular frequency changes and the time points.

3. The method for evaluating the damping characteristics of a power system according to claim 1, characterized in that, Determining the power change matrix based on the first feature information includes: The power data is fitted using the first feature information to obtain the power change matrix; Determining the angular frequency change matrix based on the second feature information includes: The angular frequency data is fitted using the second feature information to obtain the angular frequency change matrix.

4. The method for evaluating the damping characteristics of a power system according to claim 1, characterized in that, The determination of the equivalent admittance coefficient based on the power change matrix and the angular frequency change matrix includes: The ratio of the power change matrix to the angular frequency change matrix is ​​determined to obtain the equivalent admittance matrix; The equivalent admittance matrix is ​​solved to obtain the equivalent admittance coefficients.

5. The method for evaluating the damping characteristics of a power system according to claim 1, characterized in that, Before acquiring the power data and angular frequency data of the generator set within a preset time period, the method further includes: Determine whether the power system exhibits low-frequency oscillations; When the power system experiences low-frequency oscillations, the step of acquiring power data and angular frequency data of the generator set within a preset time period is performed.

6. The method for evaluating the damping characteristics of a power system according to claim 5, characterized in that, The damping characteristics include the degree of damping contribution; The generator sets are multiple; the damping characteristics of the generator sets are evaluated using the equivalent admittance coefficient to obtain evaluation results, including: For each of the plurality of generator sets, the damping contribution of the generator set is determined based on the magnitude of the equivalent admittance coefficient corresponding to the generator set. And / or, For multiple equivalent admittance coefficients belonging to the same low-frequency oscillation, the average value of the multiple equivalent admittance coefficients is determined. Based on the average value corresponding to each of the multiple low-frequency oscillations, the damping contribution of the multiple generator sets under different power system operating conditions is determined. The multiple equivalent admittance coefficients correspond one-to-one with the multiple generator sets.

7. A device for evaluating the damping characteristics of a power system, characterized in that, include: The acquisition unit is used to acquire power data and angular frequency data of the generator set within a preset time period; The generator set is the generator set in the power system; The first determining unit is configured to generate a first change curve based on the power data, determine the first feature information of the first change curve, generate a second change curve based on the angular frequency data, and determine the second feature information of the second change curve. The second determining unit is used to determine the power change matrix based on the first feature information and the angular frequency change matrix based on the second feature information. The third determining unit is used to determine the equivalent admittance coefficient based on the power change matrix and the angular frequency change matrix. An evaluation unit is used to evaluate the damping characteristics of the generator set using the equivalent admittance coefficient, and obtain the evaluation result.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, The computer program, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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