Method and device for determining sub-hyper-synchronous instantaneous power based on rotating coordinate system

Abstract

The invention provides a sub-hyper-synchronous instantaneous power determination method and device based on a rotating coordinate system, relates to the technical field of electric power, and is used for determining oscillation power and carrying out quantitative evaluation on the oscillation power so as to understand oscillation characteristics. The method comprises the following steps: under a preset condition, determining a conversion relation between voltage and current under a dq coordinate system; determining a power model under the oscillation frequency of the sub-hyper-synchronous frequency based on the conversion relation and the instantaneous power of the PCC point of the power system; acquiring element parameters and voltage parameters of the power system under the dq coordinate system; and determining the oscillation power at the oscillation frequency of the sub-hyper-synchronous frequency based on the element parameters, the voltage parameters and a power model.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method and device for determining sub-supersynchronous instantaneous power based on a rotating coordinate system. Background Art

[0002] With the continuous development of power grid technology, a large number of devices using power electronics technology have begun to be connected to the power grid. This process is called grid connection. The grid connection of power electronic equipment can improve the efficiency of energy utilization on the one hand, and enhance the flexibility of system power conversion on the other hand, playing an important role in the development of power grid technology.

[0003] However, when a large proportion of power electronic equipment is connected to the grid, various forms of multi-characteristic oscillation problems have also been triggered. In related technologies, research on oscillations mainly focuses on the causes of oscillations at the macro level, but pays insufficient attention to the nature of oscillations, especially the analysis and calculation of oscillation power.

[0004] Oscillation power can be understood as a measure of the flow and change of energy in a system during the oscillation process. Therefore, analytical calculation of oscillation power can provide a deep understanding of the characteristics of oscillation, but related technologies only have macroscopic conclusions about oscillation power, and there is no quantification of oscillation power. How to calculate oscillation power to quantify oscillation power and understand oscillation characteristics is a problem that needs to be solved urgently. Summary of the invention

[0005] In response to the problems in the related art, the present application provides a method and device for determining sub-supersynchronous instantaneous power based on a rotating coordinate system, which can quantify the oscillation power by determining the power model under the sub-supersynchronous frequency oscillation frequency, so as to understand the oscillation characteristics.

[0006] To solve the above problems, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system, comprising:

[0008] Under preset conditions, determine the conversion relationship between voltage and current in the dq coordinate system;

[0009] Based on the conversion relationship and the instantaneous power at the PCC point of the power system, the power model at the sub-supersynchronous frequency oscillation frequency is determined;

[0010] Obtain component parameters and voltage parameters of the power system in the dq coordinate system;

[0011] Based on the component parameters, the voltage parameters and the power model, the oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0012] Further, the power model includes an active power model, and the oscillating power includes an active oscillating power;

[0013] Based on the component parameters, voltage parameters and power model, the oscillation power at the sub-supersynchronous frequency oscillation frequency is determined, including:

[0014] Based on the component parameters, the voltage parameters and the active power model, the active oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0015] Furthermore, the power model also includes a reactive power model, and the oscillating power also includes reactive oscillating power;

[0016] Based on the component parameters, voltage parameters and power model, the oscillation power at the sub-supersynchronous frequency oscillation frequency is determined, including:

[0017] Based on the component parameters, the voltage parameters and the reactive power model, the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0018] Furthermore, based on the conversion relationship and the instantaneous power at the PCC point of the power system, a power model at the sub-supersynchronous frequency oscillation frequency is determined, including:

[0019] Based on the conversion relationship, determine the current model under the preset conditions;

[0020] Based on the instantaneous power at the PCC point of the power system, the initial power model at the sub-supersynchronous frequency oscillation frequency is determined;

[0021] A power model is determined based on the current model and the initial power model.

[0022] Furthermore, the component parameters include at least one of the following: an angular frequency of the power frequency, an angular frequency of the sub-supersynchronous frequency component, an equivalent resistance value and an inductance value of the line.

[0023] In a second aspect, the present application provides a sub-supersynchronous instantaneous power determination device based on a rotating coordinate system, comprising:

[0024] A relationship determination module, used to determine the conversion relationship between voltage and current in a dq coordinate system under preset conditions;

[0025] A model determination module, used for determining a power model at a sub-supersynchronous frequency oscillation frequency based on a conversion relationship and instantaneous power at a PCC point of the power system;

[0026] An acquisition module, used for acquiring component parameters and voltage parameters of the power system in a dq coordinate system;

[0027] The power determination module is used to determine the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, the voltage parameters and the power model.

[0028] Further, the power model includes an active power model, and the oscillating power includes an active oscillating power;

[0029] The power determination module is specifically used for:

[0030] Based on the component parameters, the voltage parameters and the active power model, the active oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0031] Furthermore, the power model also includes a reactive power model, and the oscillating power also includes reactive oscillating power;

[0032] The power determination module is specifically used for:

[0033] Based on the component parameters, the voltage parameters and the reactive power model, the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0034] Furthermore, the model determination module is specifically used to:

[0035] Based on the conversion relationship, determine the current model under the preset conditions;

[0036] Based on the instantaneous power at the PCC point of the power system, the initial power model at the sub-supersynchronous frequency oscillation frequency is determined;

[0037] A power model is determined based on the current model and the initial power model.

[0038] Furthermore, the component parameters include at least one of the following: an angular frequency of the power frequency, an angular frequency of the sub-supersynchronous frequency component, an equivalent resistance value and an inductance value of the line.

[0039] In a third aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the sub-supersynchronous instantaneous power determination method based on a rotating coordinate system are implemented.

[0040] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system.

[0041] In a fifth aspect, the present application provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the above-mentioned method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system.

[0042] In the technical solution provided by the present application, a power model under the sub-supersynchronous frequency oscillation frequency is established through the conversion relationship between voltage and current, and the instantaneous power of the power system. This model not only takes into account the influence of component parameters in the power system, but also takes into account the influence of voltage components and current components under the sub-supersynchronous frequency oscillation frequency. Then, by obtaining component parameters and voltage parameters and inputting them into the power model, the oscillation power can be accurately quantified and calculated, which provides an important basis for the stability analysis and optimization of the power system, improves the accuracy of the oscillation power analysis, and helps to deeply understand the nature of the oscillation phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A principle model diagram of a method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in an embodiment of the present application;

[0045] Figure 2 A schematic flow chart of a method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in an embodiment of the present application;

[0046] Figure 3 A schematic flow chart of another method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram of the structure of a wind farm grid-connected system provided in an embodiment of the present application;

[0048] Figure 5 A power waveform diagram improved by the embodiment of the present application;

[0049] Figure 6 A schematic diagram of a power ratio improved by an embodiment of the present application;

[0050] Figure 7 A schematic diagram of the structure of a sub-supersynchronous instantaneous power determination device based on a rotating coordinate system provided in an embodiment of the present application;

[0051] Figure 8 A schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] It should be noted that the method and device for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in the present application can be used in the field of power technology, and can also be used in any field outside the field of power technology. The application field of the method and device for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in the present application is not limited.

[0054] In the related art 1, the analytical calculation of the oscillation power is carried out by analyzing the propagation characteristics of the subsynchronous oscillation power under the excitation of the subsynchronous voltage source, and then the influence of the steady-state power flow and line impedance characteristics on the instantaneous power distribution of the subsynchronous oscillation is derived. However, in the derivation process, the essential characteristics of the amplitude-frequency modulation of the grid-connected equipment are ignored.

[0055] In related technology 2, the power response of the power network under amplitude-frequency modulation excitation is accurately calculated, and it is determined that the change of the potential amplitude / frequency of each node has a greater impact on reactive power transmission than active power, but no quantitative evaluation of the reactive and active power transmission characteristics is made.

[0056] Based on this, the present application provides a method and device for determining sub-supersynchronous instantaneous power based on a rotating coordinate system. By establishing a power model under sub-supersynchronous frequency oscillation, the oscillation power is accurately quantified and calculated, thereby improving the accuracy of oscillation power analysis.

[0057] Figure 1 The schematic diagram of the principle model of a sub-supersynchronous instantaneous power determination method based on a rotating coordinate system provided in this application. Figure 1 As shown, taking the existence of a sub-supersynchronous oscillation source in the system as an example, it is equivalent to an AC voltage source, and the active / reactive oscillation power of the system during forced vibration is analytically calculated according to the instantaneous power theory and harmonic analysis method. After the principle model is simplified by equivalent values, the analysis process of the oscillation power can be applied to complex power systems. It should be noted that in order to simplify and highlight the expression, in the process of determining the oscillation power, attention is paid to the derivation of the oscillation power and related components, and the influence of the mutual coupling of high-order harmonics is ignored. In addition, in order to simplify the analysis and clarify the physical meaning of the oscillation power in the power system, the relevant processes in this application are all based on the dq coordinate system.

[0058] Figure 2 A flow chart of a method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, the specific steps include:

[0059] S101. Under preset conditions, determine the conversion relationship between voltage and current in a dq coordinate system.

[0060] S102: Determine a power model at a sub-supersynchronous frequency oscillation frequency based on the conversion relationship and the instantaneous power at the PCC point of the power system.

[0061] S103. Obtain component parameters and voltage parameters of the power system in the dq coordinate system.

[0062] S104: Determine the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, voltage parameters and power model.

[0063] In this way, through the conversion relationship between voltage and current, and the instantaneous power of the power system, a power model under the sub-supersynchronous frequency oscillation frequency is established. This model not only considers the influence of component parameters in the power system, but also considers the influence of voltage components and current components under the sub-supersynchronous frequency oscillation frequency. Then, by obtaining component parameters and voltage parameters and inputting them into the power model, the oscillation power can be accurately quantified and calculated, which provides an important basis for the stability analysis and optimization of the power system, improves the accuracy of oscillation power analysis, and helps to deeply understand the nature of the oscillation phenomenon.

[0064] S101. Under preset conditions, determine the conversion relationship between voltage and current in a dq coordinate system.

[0065] Among them, the preset condition is that there are subsynchronous voltage components and current components in the circuit of the power system. Under the preset condition, the conversion relationship between voltage and current in the dq coordinate system is shown in the following formula:

[0066]

[0067] In the above formula, I d is the d-axis current component, I q is the q-axis current component, U d is the d-axis voltage component, U q is the q-axis voltage component, ω0 is the angular frequency of the power frequency, ω7 is the angular frequency of the sub-supersynchronous frequency component, R is the equivalent resistance value of the line, L is the inductance value of the line, and j is an imaginary unit used to characterize the alternating current quantity of information such as amplitude and phase.

[0068] S102: Determine a power model at a sub-supersynchronous frequency oscillation frequency based on the conversion relationship and the instantaneous power at the PCC point of the power system.

[0069] Among them, the instantaneous power at the point of common coupling (PCC) of the power system includes instantaneous active power p and instantaneous reactive power q, which can be expressed as the following formulas:

[0070]

[0071] In the above formula, U d is the d-axis voltage component, U q is the q-axis voltage component, I d is the d-axis current component, I q It is understandable that in the relevant formulas of instantaneous power, whether it is instantaneous active power or instantaneous reactive power, only the q-axis voltage component, d-axis voltage component, d-axis current component, and q-axis current component are considered in the calculation, and the voltage component influence and current component influence at the sub-supersynchronous frequency oscillation frequency are not considered.

[0072] S103. Obtain component parameters and voltage parameters of the power system in the dq coordinate system.

[0073] The component parameters include at least one of the following: the angular frequency of the power frequency, the angular frequency of the sub-supersynchronous frequency component, the equivalent resistance value of the line, and the inductance value of the line. The voltage parameters include at least one of the following: the d-axis voltage component and the q-axis voltage component.

[0074] S104: Determine the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, voltage parameters and power model.

[0075] It should be noted that the power model takes into account the influence of the voltage component at the sub-supersynchronous frequency oscillation frequency. Before determining the oscillation power, the voltage parameter needs to be converted into the oscillation voltage parameter at the sub-supersynchronous frequency oscillation frequency. Among them, the oscillation voltage parameter includes at least one of the following: DC d-axis voltage component, sub-super d-axis voltage component, DC q-axis voltage component, and sub-super q-axis voltage component.

[0076] In some embodiments, Figure 3 As shown, based on the conversion relationship and the instantaneous power at the PCC point of the power system, the power model under the sub-supersynchronous frequency oscillation frequency is determined, including the following steps:

[0077] S201. Determine a current model under preset conditions based on a conversion relationship.

[0078] In some embodiments, a matrix transformation is performed on the conversion relationship to determine a current model under preset conditions.

[0079] Among them, the current model can be represented by the following formula:

[0080]

[0081] In the above formula, I d is the d-axis current component, I q is the q-axis current component, U d is the d-axis voltage component, U q is the q-axis voltage component, ω0 is the angular frequency of the power frequency, ω7 is the angular frequency of the sub-supersynchronous frequency component, R is the equivalent resistance value of the line, L is the inductance value of the line, and j is an imaginary unit, which is used to characterize the alternating current of information such as amplitude and phase. It should be noted that the angular frequency of the power frequency, the angular frequency of the sub-supersynchronous frequency component, the equivalent resistance value and the inductance value of the line are the component-related parameters in the power system, and in this application, the above parameters are also collectively referred to as component parameters.

[0082] In this way, through matrix transformation processing, the current components in the current model are uniformly represented by voltage components, and in the subsequent process of generating a power model based on the current model, the simplicity of the mapping relationship can be improved, and it has the characteristics of symmetry. It should be noted that in this application, it is not limited to the representation relationship between the voltage component and the current component, and the voltage component can also be uniformly represented by the current component, and this application does not limit this.

[0083] S202: Determine an initial power model at a sub-supersynchronous frequency oscillation frequency based on the instantaneous power at the PCC point of the power system.

[0084] In some embodiments, the instantaneous power of the power system PCC point includes the instantaneous active power of the power system PCC point, and the oscillation power includes the active oscillation power. Correspondingly, the initial power model under the sub-supersynchronous frequency oscillation frequency includes the initial active power model. Based on the instantaneous power of the power system PCC point, determining the initial power model under the sub-supersynchronous frequency oscillation frequency can be specifically implemented as the following steps:

[0085] Based on the instantaneous active power and instantaneous power theory of the PCC point of the power system, the initial active power model under the sub-supersynchronous frequency oscillation frequency is determined.

[0086] It should be noted that instantaneous power theory is a related concept in power electronics, which is used to describe the flow and change of instantaneous power in the power system. Specifically, the initial active power model of the active oscillation power P7 is presented by the following formula:

[0087] P7=1.5(U d I d +U q I q )=1.5(U d0 I d7 +U d7 I d0 +Uq0 I q7 +U q7 I q0 )

[0088] Where P7 is the active oscillation power at the sub-supersynchronous frequency oscillation frequency, I d is the d-axis current component, I q is the q-axis current component, U d is the d-axis voltage component, U q is the q-axis voltage component, U d0 is the DC d-axis voltage component, U d7 is the sub-super d-axis voltage component, U q0 is the DC q-axis voltage component, U q7 is the sub-super q-axis voltage component, I d0 is the DC d-axis current component, I d7 is the sub-d-axis current component, I q0 is the DC q-axis current component, I q7 is the sub-super q-axis current component.

[0089] In some embodiments, the instantaneous power of the power system PCC point includes the instantaneous reactive power of the power system PCC point, and the oscillation power includes the reactive oscillation power. Correspondingly, the initial power model under the sub-supersynchronous frequency oscillation frequency includes the initial reactive power model. Based on the instantaneous power of the power system PCC point, determining the initial power model under the sub-supersynchronous frequency oscillation frequency can be specifically implemented as the following steps:

[0090] Based on the instantaneous reactive power and instantaneous power theory of the PCC point of the power system, the initial reactive power model under the sub-supersynchronous frequency oscillation frequency is determined.

[0091] Specifically, the initial active power model of the reactive oscillating power Q7 is presented by the following formula:

[0092] Q7=1.5(U d I q -U d I q )=1.5(U q0 I d7 +U q7 I d0 -U d0 I q7 -U d7 I q0 )

[0093] Where Q7 is the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency, I d is the d-axis current component, I q is the q-axis current component, U d is the d-axis voltage component, Uq is the q-axis voltage component, U d0 is the DC d-axis voltage component, U d7 is the sub-super d-axis voltage component, U q0 is the DC q-axis voltage component, U q7 is the sub-super q-axis voltage component, I d0 is the DC d-axis current component, I d7 is the sub-d-axis current component, I q0 is the DC q-axis current component, I q7 is the sub-super q-axis current component.

[0094] It can be understood that, without considering the high-order harmonic coupled subsynchronous components, the initial active power model of active power P7 and the initial reactive power model of reactive power Q7 include a total of four items, all of which are generated by the interaction between the subsynchronous voltage and current and the DC quantity.

[0095] It should be noted that the initial power model under the sub-supersynchronous frequency oscillation frequency can only characterize the correlation between oscillation and voltage and current. In practice, the oscillation power of the power system involves the interaction of multiple frequency components, including but not limited to the power frequency, sub-supersynchronous frequency, etc. There is a complex coupling relationship between these components, which directly affects the accuracy of the calculation of the oscillation power. Therefore, it is impossible to directly use the initial power model to quantify the oscillation power and calculate the accuracy. The initial power model needs to be further processed to obtain a more accurate power model.

[0096] S203: Determine a power model based on the current model and the initial power model.

[0097] In some embodiments, the current model is fused into the initial power model to obtain the power model.

[0098] Specifically, taking the active power model of active power P7 as an example, after substituting the current model into the initial active power model of active power, the generated active power model can be represented by the following formula:

[0099]

[0100] Correspondingly, the reactive power model of reactive power P7 can be represented by the following formula:

[0101]

[0102] Wherein, P7 is the active power of the active oscillation power at the sub-supersynchronous frequency oscillation frequency, Q7 is the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency, and U d0 is the DC d-axis voltage component, U d7 is the sub-super d-axis voltage component, Uq0 is the DC q-axis voltage component, U q7 is the sub-super q-axis voltage component, ω0 is the angular frequency of the power frequency, ω7 is the angular frequency of the sub-super synchronous frequency component, R is the equivalent resistance value of the line, L is the inductance value of the line, j is an imaginary unit, and is used to characterize the alternating current quantity of information such as amplitude and phase.

[0103] In some embodiments, the power model includes an active power model, and the oscillation power includes active oscillation power; based on component parameters, voltage parameters and the power model, the oscillation power at a sub-supersynchronous frequency oscillation frequency is determined, including: based on component parameters, voltage parameters and the active power model, the active oscillation power at a sub-supersynchronous frequency oscillation frequency is determined.

[0104] The component parameters include at least one of the following: the angular frequency of the power frequency, the angular frequency of the sub-supersynchronous frequency component, the equivalent resistance value and the inductance value of the line. The voltage parameters include at least one of the following: U d0 is the DC d-axis voltage component, U d7 is the sub-super d-axis voltage component, U q0 is the DC q-axis voltage component, U q7 is the sub-super q-axis voltage component.

[0105] Exemplarily, after the component parameters and the voltage parameters are acquired, the component parameters and the voltage parameters are input into an active power model at a sub-supersynchronous frequency oscillation frequency, so that the active oscillation power at the sub-supersynchronous frequency oscillation frequency can be determined.

[0106] In some embodiments, the power model also includes a reactive power model, and the oscillation power also includes reactive oscillation power; based on component parameters, voltage parameters and the power model, the oscillation power at the sub-supersynchronous frequency oscillation frequency is determined, including: based on component parameters, voltage parameters and the reactive power model, the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0107] The component parameters include at least one of the following: the angular frequency of the power frequency, the angular frequency of the sub-supersynchronous frequency component, the equivalent resistance value and the inductance value of the line. The voltage parameters include at least one of the following: U d0 is the DC d-axis voltage component, U d7 is the sub-super d-axis voltage component, U q0 is the DC q-axis voltage component, U q7 is the sub-super q-axis voltage component.

[0108] Exemplarily, after the component parameters and the voltage parameters are acquired, the component parameters and the voltage parameters are input into a reactive power model at a sub-supersynchronous frequency oscillation frequency, so that the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency can be determined.

[0109] It should be noted that active oscillation power refers to the energy part that is actually converted into other forms of energy (such as mechanical energy, thermal energy, etc.) in the oscillation circuit. It is the actual useful power part in the oscillation circuit. Reactive oscillation power refers to the energy oscillation part generated in the oscillation circuit due to the presence of inductance and capacitance. It is not the energy part that is actually converted into other forms of energy, but the process of storing and releasing energy in the circuit. Active oscillation power can also be described as active power, and reactive oscillation power can also be described as reactive power, which is not limited by the comparison in this application.

[0110] In the technical solution provided by the present application, a power model under the sub-supersynchronous frequency oscillation frequency is established through the conversion relationship between voltage and current, and the instantaneous power of the power system. This model not only takes into account the influence of component parameters in the power system, but also takes into account the influence of voltage components and current components under the sub-supersynchronous frequency oscillation frequency. Then, by obtaining component parameters and voltage parameters and inputting them into the power model, the oscillation power can be accurately quantified and calculated, which provides an important basis for the stability analysis and optimization of the power system, improves the accuracy of the oscillation power analysis, and helps to deeply understand the nature of the oscillation phenomenon.

[0111] Furthermore, the ratio of the instantaneous active power to the reactive power at the sub-supersynchronous frequency can be determined by the active power model of the active power and the reactive power model of the reactive power:

[0112]

[0113] Next, based on the above formula, determine the peak ratio of active power to reactive power:

[0114]

[0115] Based on the above peak ratio, it can be seen that as the oscillation frequency increases, the instantaneous ratio of active oscillation power to reactive oscillation power will gradually increase. When supersynchronous oscillation occurs in the power system, the instantaneous ratio of active oscillation power to reactive oscillation power will be greater than 1, indicating that the active oscillation power is usually greater than the reactive oscillation power amplitude. This result is consistent with oscillation-related experience or theory.

[0116] Figure 4 The schematic diagram of the structure of a wind farm grid-connected system is shown, which is made by Matlab or Simulink and is used to simulate and verify the reliability of the active power and reactive power oscillation amplitude ratio obtained above. Figure 4 As shown, the wind farm grid-connected system includes wind farm 1, wind farm 2, wind farm 3 and other electrical components.

[0117] Further, such as Figure 5As shown in the figure, (a) is the instantaneous power waveform under 39.1Hz harmonic incentive, and (b) is the instantaneous power waveform under 7Hz harmonic incentive. It can also be seen from the waveform that the instantaneous power contains oscillating power.

[0118] like Figure 6 As shown, it is the ratio of active power to reactive power of different line oscillations at different frequencies. It can be seen that the calculation result determined according to the target mapping relationship of the oscillation power provided by the present application is basically consistent with the trend of the simulation result.

[0119] It is worth noting that the acquisition, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of laws and regulations. The user information in the embodiments of this application is obtained through legal and compliant channels, and the acquisition, storage, use, and processing of user information are authorized and agreed by the customer.

[0120] It is worth noting that the information collected in this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with the relevant laws, regulations and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0121] It is worth noting that the technical solution provided in this application provides users with corresponding operation entrances for them to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered.

[0122] Figure 7 Schematic diagram of the structure of a sub-supersynchronous instantaneous power determination device based on a rotating coordinate system provided in an embodiment of the present application, the device is used to execute the above-mentioned sub-supersynchronous instantaneous power determination method based on a rotating coordinate system, such as Figure 7 As shown, the sub-supersynchronous instantaneous power determination device based on the rotating coordinate system includes: a relationship determination module 701, a model determination module 702, an acquisition module 703 and a power determination module 704.

[0123] A relationship determination module 701 is used to determine the conversion relationship between voltage and current in a dq coordinate system under preset conditions;

[0124] The model determination module 702 is used to determine the power model at the sub-supersynchronous frequency oscillation frequency based on the conversion relationship and the instantaneous power at the PCC point of the power system;

[0125] An acquisition module 703 is used to acquire component parameters and voltage parameters of the power system in a dq coordinate system;

[0126] The power determination module 704 is used to determine the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, the voltage parameters and the power model.

[0127] Further, the power model includes an active power model, and the oscillating power includes an active oscillating power;

[0128] The power determination module 704 is specifically configured to:

[0129] Based on the component parameters, the voltage parameters and the active power model, the active oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0130] Furthermore, the power model also includes a reactive power model, and the oscillating power also includes reactive oscillating power;

[0131] The power determination module 704 is specifically configured to:

[0132] Based on the component parameters, the voltage parameters and the reactive power model, the reactive oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

[0133] Furthermore, the model determination module 702 is specifically configured to:

[0134] Based on the conversion relationship, determine the current model under the preset conditions;

[0135] Based on the instantaneous power at the PCC point of the power system, the initial power model at the sub-supersynchronous frequency oscillation frequency is determined;

[0136] A power model is determined based on the current model and the initial power model.

[0137] Furthermore, the component parameters include at least one of the following: an angular frequency of the power frequency, an angular frequency of the sub-supersynchronous frequency component, an equivalent resistance value and an inductance value of the line.

[0138] In the technical solution provided by the present application, a power model under the sub-supersynchronous frequency oscillation frequency is established through the conversion relationship between voltage and current, and the instantaneous power of the power system. This model not only takes into account the influence of component parameters in the power system, but also takes into account the influence of voltage components and current components under the sub-supersynchronous frequency oscillation frequency. Then, by obtaining component parameters and voltage parameters and inputting them into the power model, the oscillation power can be accurately quantified and calculated, which provides an important basis for the stability analysis and optimization of the power system, improves the accuracy of the oscillation power analysis, and helps to deeply understand the nature of the oscillation phenomenon.

[0139] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer device, and specifically, the computer device may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0140] An embodiment of the present invention provides a computer device, including a memory and a processor, the memory is used to store information including program instructions, the processor is used to control the execution of the program instructions, and when the program instructions are loaded and executed by the processor, the steps of the embodiment of the above-mentioned transient voltage assessment method based on the power grid topology structure are implemented. For a specific description, please refer to the embodiment of the above-mentioned transient voltage assessment method based on the power grid topology structure.

[0141] Reference below Figure 8 , which shows a schematic diagram of the structure of a computer device 800 suitable for implementing an embodiment of the present application.

[0142] like Figure 8 As shown, the computer device 800 includes a central processing unit (CPU) 801, which can perform various appropriate operations and processes according to a program stored in a read-only memory (ROM) 802 or a program loaded from a storage part 808 into a random access memory (RAM) 803. In the RAM 803, various programs and data required for the operation of the computer device 800 are also stored. The CPU 801, the ROM 802, and the RAM 803 are connected to each other via a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0143] The following components are connected to the I / O interface 805: an input section 806 including a keyboard, a mouse, etc.; an output section 807 including a cathode ray tube (CRT), a liquid crystal feedback device (LCD), etc., and a speaker, etc.; a storage section 808 including a hard disk, etc.; and a communication section 809 including a network interface card such as a LAN card, a modem, etc. The communication section 809 performs communication processing via a network such as the Internet. A drive 810 is also connected to the I / O interface 805 as needed. A removable medium 811, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 810 as needed, so that a computer program read therefrom is installed as needed as the storage section 808.

[0144] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program tangibly contained on a machine-readable medium, and the computer program includes program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 809, and / or installed from the removable medium 811.

[0145] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0146] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0147] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0148] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0149] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0150] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0151] The acquisition, storage, use, and processing of data in the technical solution of this application comply with the relevant provisions of national laws and regulations.

[0152] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned, and they should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0153] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0154] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0155] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0156] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system, characterized in that: The method comprises: Under preset conditions, determine the conversion relationship between voltage and current in the dq coordinate system; Based on the conversion relationship and the instantaneous power at the PCC point of the power system, a power model at a sub-supersynchronous frequency oscillation frequency is determined; Obtain component parameters and voltage parameters of the power system in the dq coordinate system; Based on the component parameters, the voltage parameters and the power model, an oscillation power at a sub-supersynchronous frequency oscillation frequency is determined.

2. The method according to claim 1, characterized in that: The power model includes an active power model, and the oscillation power includes an active oscillation power; The determining the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, the voltage parameters and the power model includes: Based on the component parameters, the voltage parameters and the active power model, the active oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

3. The method according to claim 1, characterized in that The power model also includes a reactive power model, and the oscillating power also includes reactive oscillating power; The determining the oscillation power at the sub-supersynchronous frequency oscillation frequency based on the component parameters, the voltage parameters and the power model includes: Based on the component parameters, the voltage parameters and the reactive power model, the reactive oscillation power at a sub-supersynchronous frequency oscillation frequency is determined.

4. The method according to claim 1, characterized in that The determining of the power model at the sub-supersynchronous frequency oscillation frequency based on the conversion relationship and the instantaneous power at the PCC point of the power system includes: Based on the conversion relationship, determining a current model under the preset conditions; Determining an initial power model at a sub-supersynchronous frequency oscillation frequency based on the instantaneous power at the PCC point of the power system; The power model is determined based on the current model and the initial power model.

5. The method according to any one of claims 1 or 3, characterized in that: The component parameters include at least one of the following: an angular frequency of the power frequency, an angular frequency of the sub-supersynchronous frequency component, an equivalent resistance value and an inductance value of the line.

6. A sub-supersynchronous instantaneous power determination device based on a rotating coordinate system, characterized in that: The device comprises: A relationship determination module, used to determine the conversion relationship between voltage and current in a dq coordinate system under preset conditions; A model determination module, used to determine the power model at the sub-supersynchronous frequency oscillation frequency based on the conversion relationship and the instantaneous power of the PCC point of the power system; An acquisition module, used for acquiring component parameters and voltage parameters of the power system in a dq coordinate system; The power determination module is used to determine the oscillation power at a sub-supersynchronous frequency oscillation frequency based on the component parameters, the voltage parameters and the power model.

7. The device according to claim 6, characterized in that The power model includes an active power model, and the oscillation power includes an active oscillation power; The power determination module is specifically used for: Based on the component parameters, the voltage parameters and the active power model, the active oscillation power at the sub-supersynchronous frequency oscillation frequency is determined.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the sub-supersynchronous instantaneous power determination method based on a rotating coordinate system according to any one of claims 1 to 5 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for determining sub-supersynchronous instantaneous power based on a rotating coordinate system according to any one of claims 1 to 5 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the sub-supersynchronous instantaneous power determination method based on a rotating coordinate system as described in any one of claims 1 to 5 are implemented.

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