Positive and negative sequence electric quantity separation method and device

Abstract

The invention provides a positive and negative sequence electric quantity separation method and device. The method comprises the steps of obtaining an instantaneous electric quantity signal in a three-phase power grid; performing phase angle deviation of a preset angle on the instantaneous electric quantity signal based on an all-pass filter to obtain an instantaneous orthogonal electric quantity signal; and determining a positive sequence component and a negative sequence component of the instantaneous electric quantity signal according to the instantaneous electric quantity signal and the instantaneous orthogonal electric quantity signal. The phase angle deviation of the preset angle is performed on the instantaneous electric quantity signal based on the all-pass filter so as to acquire the instantaneous orthogonal electric quantity signal, and the phase angle deviation can be realized with extremely high precision by utilizing the characteristic that the all-pass filter keeps the amplitude response constant in the whole frequency range and only changes the phase of the signal, so that the error caused by the amplitude change is avoided. According to the method, the instantaneous orthogonal electric quantity signal is obtained firstly, then the positive sequence component and the negative sequence component are determined in combination with the instantaneous electric quantity signal, the positive sequence component and the negative sequence component are rapidly obtained in a three-phase power grid system with the high real-time performance requirement by means of the orthogonal relation between the signals, and error analysis is facilitated.

Description

Technical Field

[0001] This application relates to the field of power control technology, and in particular to a method and apparatus for separating positive and negative sequence electrical quantities. Background Technology

[0002] Power system asymmetric faults caused by imbalances in three-phase parameters or operating conditions are prone to negative-sequence fundamental wave components. These components can cause generator oscillations and overcurrents, uneven heating of converter windings, and reduced output of asynchronous motors, thus threatening the stability of the power system.

[0003] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0004] The purpose of this application is to at least partially solve one of the technical problems in the related art.

[0005] Therefore, the first objective of this application is to propose a method for separating positive and negative sequence charges.

[0006] The second objective of this application is to provide a positive and negative sequence electrical charge separation device.

[0007] The third objective of this application is to propose an electronic device.

[0008] The fourth objective of this application is to provide a computer-readable storage medium.

[0009] The fifth objective of this application is to provide a computer program product.

[0010] To achieve the above objectives, a first aspect of this application proposes a method for separating positive and negative sequence charges, comprising: Acquire instantaneous electrical signals in a three-phase power grid; The instantaneous electrical signal is obtained by shifting the phase angle of the instantaneous electrical signal by a preset angle based on an all-pass filter; Based on the instantaneous electrical signal and the instantaneous orthogonal electrical signal, determine the positive-sequence component and the negative-sequence component of the instantaneous electrical signal.

[0011] To achieve the above objectives, a second aspect of this application provides a positive-negative sequence charge separation device, which is configured to implement the steps of the positive-negative sequence charge separation method proposed in the first aspect of this application.

[0012] To achieve the above objectives, a third aspect of this application provides an electronic device, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to execute the instructions to implement the positive and negative order charge separation method proposed in the first aspect of this application.

[0013] To achieve the above objectives, a fourth aspect of this application provides a computer-readable storage medium that, when the instructions in the storage medium are executed by a processor of an electronic device, enables the electronic device to perform the positive and negative order charge separation method proposed in the first aspect of this application.

[0014] To achieve the above objectives, a fifth aspect of this application provides a computer program product, including a computer program that, when executed by a processor in a communication device, implements the positive and negative sequence charge separation method proposed in the first aspect of this application.

[0015] In this embodiment, an instantaneous orthogonal electrical signal is obtained by shifting the instantaneous electrical signal by a preset angle using an all-pass filter. Utilizing the characteristic of the all-pass filter to maintain a constant amplitude response across the entire frequency range while only changing the signal phase, the phase shift can be achieved with extremely high precision, avoiding errors introduced by amplitude variations. By first obtaining the instantaneous orthogonal electrical signal and then combining it to determine the positive and negative sequence components, the orthogonality between the signals simplifies the complex mathematical extrapolation process. This facilitates the rapid acquisition of positive and negative sequence components in three-phase power grid systems with high real-time requirements, enabling error analysis and reducing calculation errors caused by interference.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating a method for separating positive and negative sequence charges provided in an embodiment of this application. Figure 2 This is a flowchart illustrating another method for separating positive and negative order charges provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a” and “the” as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] It should be understood that although the terms first, second, third, etc., may be used to describe various information in the embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words "if" and "suppose" as used herein can be interpreted as "when," "when," or "in response to a determination."

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0022] Asymmetrical faults in the power grid caused by imbalances in three-phase parameters or operating conditions are a significant factor threatening the safe and stable operation of the power grid. Ideally, the three-phase parameters in a power system should be in a symmetrical and balanced state, meaning that the three-phase voltages and currents are equal in magnitude and 120° out of phase. However, in actual operation, due to interference from various factors, this ideal state is often difficult to maintain.

[0023] In some scenarios, a single-phase grounding fault may exist in the transmission line, causing a significant change in the electrical parameters of a certain phase; or in the case of uneven power load distribution, the power difference of the three-phase load is too large, making it impossible for the three-phase current to maintain balance; or faults such as inter-turn short circuits in transformer windings and non-full-phase operation of circuit breakers may also disrupt the symmetry of the three-phase system.

[0024] In certain scenarios, when these asymmetries occur, a negative-sequence fundamental component is generated in the power system according to the principles of electromagnetic induction and circuit theory. Unlike the positive-sequence fundamental component, the negative-sequence fundamental component has the same magnitude of three-phase voltage or current, but its phase sequence is reversed; that is, phases A, B, and C lag by 120° sequentially, instead of phases A, C, and B lag by 120° sequentially. This unique electrical characteristic means that once the negative-sequence fundamental component is generated, it will trigger a series of chain reactions in the power system.

[0025] In some scenarios, when power systems exhibit asymmetry, negative-sequence fundamental components are generated. When these components flow into the stator windings of a generator, they create a rotating magnetic field inside the generator that rotates in the opposite direction to the rotor's rotation. This opposing rotating magnetic field interacts with the rotor's own rotating magnetic field, inducing an alternating electromagnetic torque on the rotor at twice the system frequency. This alternating electromagnetic torque causes severe vibrations and oscillations in the generator. Prolonged vibration and oscillation not only loosen connections between generator components and increase mechanical wear, but may also cause fatigue damage to the rotor shaft system, shortening the generator's lifespan.

[0026] In some scenarios, negative-sequence fundamental current can also lead to uneven current distribution in the generator stator windings. The presence of negative-sequence current causes increased winding current in some phases while decreasing current in others. This current imbalance can cause localized overheating of the windings, resulting in excessively high temperatures in certain areas. Excessive temperature accelerates the aging of the winding insulation material, reducing its insulation performance and increasing the risk of short circuits. Once a short circuit occurs, it can trigger more serious faults, potentially causing generator shutdown and severely impacting the normal power supply of the power system.

[0027] In some scenarios, negative-sequence fundamental current can adversely affect the normal operation of a converter. In a converter, each phase winding is a key component for power conversion. When a negative-sequence fundamental current flows into the converter, it causes inconsistent current magnitudes in each phase winding. Due to these current differences, the heat generated in each phase winding will also vary. Some windings may overheat due to excessive current, while others may not be able to fully utilize their conversion capacity due to insufficient current.

[0028] In some scenarios, negative-sequence fundamental current can reduce the output power of an asynchronous motor. When an asynchronous motor is connected to a power grid containing a negative-sequence fundamental component, the negative-sequence current generates a rotating magnetic field inside the motor that rotates in the opposite direction to the rotor's rotation. This reverse rotating magnetic field interacts with the rotor current, generating a braking torque. The presence of this braking torque offsets a portion of the motor's positive torque, reducing the total output torque. With reduced output torque, the motor can only increase torque by increasing the current. However, increasing the current leads to increased copper losses, meaning more heat is generated as the current flows through the windings. Excessive copper losses raise the motor's temperature, further affecting its performance. Simultaneously, due to the reduced output torque, the motor's speed also decreases, failing to reach its rated speed. This weakens the motor's ability to drive a load.

[0029] The following describes a method and apparatus for separating positive and negative sequence electrical charges according to embodiments of this application, with reference to the accompanying drawings.

[0030] Figure 1 This is a flowchart illustrating a method for separating positive and negative sequence charge levels, as provided in an embodiment of this application.

[0031] like Figure 1 As shown, the positive and negative sequence charge separation method includes, but is not limited to, the following steps: S101, acquire the instantaneous power signal in the three-phase power grid.

[0032] In one feasible implementation, accurately acquiring instantaneous electrical signals in a three-phase power grid is a crucial task in the field of power system monitoring and analysis. Instantaneous electrical signals encompass several key parameters, primarily including instantaneous voltage, instantaneous current, and the derived instantaneous power. In some scenarios, instantaneous voltage reflects the potential difference between phases of the power grid at a specific moment, and its accurate measurement is crucial for assessing voltage quality and detecting anomalies such as voltage fluctuations and distortions. For example, in power grids with extensive integration of power electronic devices, nonlinear loads can cause voltage waveform distortion. By acquiring instantaneous voltage signals in real time, the degree and composition of the distortion can be accurately analyzed, providing a basis for taking appropriate mitigation measures.

[0033] In some scenarios, instantaneous current characterizes the rate of charge flow through each phase of the power grid. It not only reflects the real-time power demand of the load but also reveals fault information in the power grid. For example, a short-circuit fault can cause a sharp increase in current. By monitoring changes in instantaneous current, the location of the fault can be quickly identified, and protective measures can be taken to prevent the fault from escalating and the equipment from being damaged.

[0034] In some scenarios, instantaneous power, as the instantaneous product of voltage and current, is categorized into active power, reactive power, and apparent power. Active power represents the actual work done, representing the rate at which electrical energy is converted into other forms of energy (such as mechanical energy, heat energy, etc.). Reactive power is related to the inductive and capacitive elements in the power grid, used to establish and maintain magnetic and electric fields. Although it does not directly perform work, it has a significant impact on the voltage stability and operating efficiency of the power grid. Apparent power is the product of the effective values ​​of voltage and current, reflecting the capacity requirements of power grid equipment. Accurately acquiring instantaneous power signals helps optimize the operation of the power grid, improve energy utilization efficiency, and reduce line losses.

[0035] S102, based on the all-pass filter, the instantaneous electrical signal is phase-shifted by a preset angle to obtain an instantaneous orthogonal electrical signal.

[0036] In one feasible implementation, instantaneous electrical signals typically include instantaneous voltage and current signals, both of which carry crucial information about energy transmission and conversion in a power system. However, raw instantaneous electrical signals may not meet certain analytical requirements. For example, orthogonal electrical signals are needed when constructing state estimation models of power systems and performing harmonic analysis for accurate power measurement. Orthogonal signals mean that the phase difference between the two signals is 90°. This characteristic gives the two signals unique advantages in mathematical processing, simplifying calculations and improving the accuracy of the analysis.

[0037] In one feasible implementation, the all-pass filter maintains the same amplitude response for signals of all frequencies, changing only the phase of the signal. Its transfer function typically has a complex distribution of poles and zeros. By designing the positions of these poles and zeros, precise adjustment of the phase of instantaneous electrical signals can be achieved.

[0038] In some embodiments, the general term formula of the all-pass filter is:

[0039] Where b and c are the coefficients of the all-pass filter, X(s) represents the input, and Y(s) represents the output. Substituting 's' into the transfer function, we get:

[0040] Among them, amplitude-frequency characteristics If the phase angle offset is 90°, then .assumed , At this point, the general term formula for the all-pass filter is expressed as:

[0041] In summary, by rationally designing the parameters of the all-pass filter, the instantaneous electrical signal is offset by 90° to obtain an orthogonal instantaneous electrical signal. In an active power filtering control system based on instantaneous reactive power theory, the instantaneous orthogonal electrical signal can accurately acquire instantaneous reactive and active power, thereby achieving efficient harmonic compensation and reactive power regulation.

[0042] S103, Based on the instantaneous electrical signal and the instantaneous orthogonal electrical signal, determine the positive sequence component and the negative sequence component of the instantaneous electrical signal.

[0043] In one feasible implementation, historical energy signals and historical quadrature energy signals in a three-phase power grid are acquired. In some embodiments, based on the instantaneous energy signal of the current sampling period, the energy signals of the previous two sampling periods (i.e., the first two frames) are acquired as historical energy signals, which include the energy signal of the previous frame and the energy signals of the first two frames; the quadrature energy signals of the previous two sampling periods are acquired as historical quadrature energy signals, which include the quadrature energy signal of the previous frame and the quadrature energy signals of the first two frames.

[0044] In one feasible implementation, the correspondence between instantaneous orthogonal electrical signals and historical electrical signals, and between historical orthogonal electrical signals and instantaneous electrical signals, is determined, and the positive-sequence component and negative-sequence component of the instantaneous electrical signals are obtained based on the correspondence.

[0045] In some embodiments, the transfer function of the all-pass filter is transformed into a difference equation.

[0046] For example, Substituting into the general term formula of the all-pass filter In the middle, we obtained The z-transform is:

[0047] Further simplification yields:

[0048] Divide both the numerator and denominator of the above expression by . get:

[0049] Then, the z-transform is used to transform the equation into a difference equation: y(t) multiplied by z equals y(t+T), and y(t) divided by z equals y(tT). The above relationship is then transformed as follows:

[0050] Will Substituting c=0 into the above expression, we obtain the formula for separating positive and negative orders:

[0051] Among them, T S For the sampling period, U N U is an instantaneous power signal. N _T S U represents the charge signal from the previous sampling period (previous frame). N _2T S This refers to the electrical signal from the first two sampling cycles (the first two frames). The quadrature electrical signal of the previous beat, These are the orthogonal electrical signals from the first two beats. It is an instantaneous orthogonal electrical signal.

[0052] As an example, based on the positive and negative sequence separation formula, the positive and negative sequence components are obtained. In a three-phase circuit, for any set of asymmetrical three-phase electrical vectors, it can be decomposed into a positive sequence vector, a negative sequence vector, and a zero sequence vector. When phase a is taken as the reference phase, the relationship between the phase a electrical vector and its symmetrical components (taking voltage as an example) is as follows:

[0053] in, Let a be the positive sequence vector of phase a. Let a be the negative order vector of phase a. Let a be the zero-order vector of phase a. , .

[0054] The relationship between the phase b charge vector and its symmetrical components (taking voltage as an example) is as follows:

[0055] The relationship between the c-phase charge vector and its symmetrical components (taking voltage as an example) is as follows:

[0056] Organize the phase a electrical vector, phase b electrical vector, and phase c electrical vector into instantaneous value form:

[0057]

[0058]

[0059] in, , , It is an instantaneous voltage signal. , , This is the positive-sequence component of the instantaneous voltage signal. , , It is the negative-sequence component of the instantaneous voltage signal. , , This is the zero-sequence component of the instantaneous voltage signal.

[0060] Performing the Clarke transform on the positive-order and negative-order components yields:

[0061] Performing the Park transformation on the above relation yields:

[0062]

[0063] in, Based on the vector angle of the positive sequence voltage signal, .

[0064] It should be noted that, after Clarke transform and Parker transform of the positive and negative sequence components, a control signal that can be used to perform error analysis on a three-phase power grid is obtained.

[0065] In summary, the positive and negative sequence electrical quantity separation method provided in this application is based on using an all-pass filter to perform a preset angle phase shift on the instantaneous electrical quantity signal to obtain an instantaneous orthogonal electrical quantity signal. Utilizing the characteristic of the all-pass filter to maintain a constant amplitude response across the entire frequency range and only change the signal phase, the phase shift can be achieved with extremely high precision, avoiding errors introduced by amplitude variations. By first obtaining the instantaneous orthogonal electrical quantity signal and then combining it to determine the positive and negative sequence components, the orthogonality between the signals simplifies the complex mathematical extrapolation process. This facilitates the rapid acquisition of positive and negative sequence components in three-phase power grid systems with high real-time requirements, enabling error analysis and reducing calculation errors caused by interference.

[0066] Figure 2 This is a flowchart illustrating another method for separating positive and negative order electrical charges provided in an embodiment of this application.

[0067] like Figure 2 As shown, the positive and negative sequence charge separation method includes, but is not limited to, the following steps: S201, acquires raw signals from the three-phase power grid based on a preset sampling frequency.

[0068] In one feasible implementation, according to Shannon's sampling theorem, the preset sampling frequency f S (f) S = 1 / T SThe sampling frequency f should be at least twice the highest frequency component of the original signal in the three-phase power grid. For example, if the fundamental frequency of the three-phase power grid is 50Hz, and various harmonic components are present, then the sampling frequency f... S Typically, the sampling frequency is several times or even higher than the fundamental frequency of the sensor, and the common sampling frequency is f. S 1kHz, 2kHz, etc., to ensure that high-frequency details and transient changes in the original signal can be captured.

[0069] S202 performs analog-to-digital conversion on the original signal to obtain the instantaneous electrical quantity signal, which includes the instantaneous voltage signal and the instantaneous current signal.

[0070] In one feasible implementation, the original signal is sampled at equal intervals using a preset sampling frequency to obtain an instantaneous electrical signal. In some embodiments, when monitoring the original signal of phase a, the original signal is captured by analog-to-digital conversion at the beginning of each sampling period to generate discrete electrical signal sampling points. The discrete electrical signal sampling points are then quantized and encoded to obtain the instantaneous electrical signal.

[0071] S203, based on the all-pass filter, performs a phase angle shift of the instantaneous electrical signal by a preset angle to obtain an instantaneous orthogonal electrical signal.

[0072] In one feasible implementation, the transfer function of the all-pass filter is obtained. A bilinear transformation is performed on the transfer function to obtain a difference equation. The instantaneous electrical signal is then phase-shifted by a preset angle based on the difference equation to obtain an instantaneous orthogonal electrical signal.

[0073] For a further detailed description of step S203, please refer to the description in the above embodiments, which will not be repeated here.

[0074] S204. Based on the instantaneous electrical signal and the instantaneous orthogonal electrical signal, determine the positive sequence component and the negative sequence component of the instantaneous electrical signal.

[0075] In one feasible implementation, historical electrical quantity signals and historical orthogonal electrical quantity signals from a three-phase power grid are acquired. Based on the difference equation corresponding to the all-pass filter, the historical electrical quantity signals, historical orthogonal electrical quantity signals, and instantaneous electrical quantity signals are used as input variables, and the instantaneous orthogonal electrical quantity signals are used as output variables. The input and output variables are fitted to obtain a correspondence. Based on this correspondence, the positive-sequence and negative-sequence components of the instantaneous electrical quantity signals are obtained. Clarke transform and Parker transform are performed on the positive-sequence and negative-sequence components to obtain control signals used for error analysis of the three-phase power grid.

[0076] As an example, if the sampling frequency is 3kHz, calculate the parameters in the following expression.

[0077] in, , , .

[0078] Furthermore, we obtain:

[0079] The positive and negative components are obtained through the above expressions.

[0080] In summary, the positive and negative sequence electrical quantity separation method provided in this application is based on using an all-pass filter to perform a preset angle phase shift on the instantaneous electrical quantity signal to obtain an instantaneous orthogonal electrical quantity signal. Utilizing the characteristic of the all-pass filter to maintain a constant amplitude response across the entire frequency range and only change the signal phase, the phase shift can be achieved with extremely high precision, avoiding errors introduced by amplitude variations. By first obtaining the instantaneous orthogonal electrical quantity signal and then combining it to determine the positive and negative sequence components, the orthogonality between the signals simplifies the complex mathematical extrapolation process. This facilitates the rapid acquisition of positive and negative sequence components in three-phase power grid systems with high real-time requirements, enabling error analysis and reducing calculation errors caused by interference.

[0081] Corresponding to the positive and negative sequence charge separation method, this application also provides a positive and negative sequence charge separation device. Since the embodiment of the positive and negative sequence charge separation device corresponds to the above-described embodiment of the positive and negative sequence charge separation method, details not disclosed in the embodiment of the positive and negative sequence charge separation device can be referred to the embodiment of the positive and negative sequence charge separation method, and will not be repeated here.

[0082] In one feasible implementation, the positive and negative sequence power separation device is configured to perform the steps of the positive and negative sequence power separation method provided in the embodiments of this application. The positive and negative sequence power separation device has specific functional modules, algorithms, or logic, and is capable of determining the positive and negative sequence components of an instantaneous power signal according to a series of steps, rules, and strategies of the positive and negative sequence power separation method described in the embodiments of this application.

[0083] In one feasible implementation, by writing specific program code, the positive and negative sequence electrical quantity separation method is transformed into instructions that the positive and negative sequence electrical quantity separation device can understand and execute. These codes may include logic such as condition judgment, loop control, and data processing, which are used to determine the positive and negative sequence components of the instantaneous electrical quantity signal.

[0084] The methods and apparatus provided in the embodiments of this application have been described above. To achieve the functions of the methods provided in the embodiments of this application, the methods and apparatus can be further refined using electronic devices.

[0085] Figure 3This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Figure 3 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0086] like Figure 3 As shown, the electronic device 300 includes a processor 301, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 302 or a program loaded from memory 306 into a random access memory (RAM) 303. The RAM 303 also stores various programs and data required for the operation of the electronic device 300. The processor 301, ROM 302, and RAM 303 are interconnected via a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0087] The following components are connected to I / O interface 305: memory 306 including hard disks, etc.; and communication section 307 including network interface cards such as LAN (Local Area Network) cards, modems, etc., which performs communication processing via a network such as the Internet; and driver 308 is also connected to I / O interface 305 as needed.

[0088] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 307. When the computer program is executed by processor 301, it performs the functions defined in the methods of this application.

[0089] In an exemplary embodiment, a storage medium including instructions is also provided, such as a memory including instructions, which can be executed by a processor 301 of an electronic device 300 to perform the above-described method. Optionally, the storage medium may be a non-transitory computer-readable storage medium, such as a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0090] In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wireline, optical fiber, RF, etc., or any suitable combination thereof.

[0091] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0092] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for separating positive and negative sequence charges, characterized in that, include: Acquire instantaneous electrical signals in a three-phase power grid; The instantaneous electrical signal is obtained by shifting the phase angle of the instantaneous electrical signal by a preset angle based on an all-pass filter; Based on the instantaneous electrical signal and the instantaneous orthogonal electrical signal, determine the positive-sequence component and the negative-sequence component of the instantaneous electrical signal.

2. The method according to claim 1, characterized in that, The acquisition of instantaneous power signals in a three-phase power grid includes: The raw signals in the three-phase power grid are acquired based on a preset sampling frequency; The original signal is converted from analog to digital to obtain an instantaneous electrical quantity signal, wherein the instantaneous electrical quantity signal includes an instantaneous voltage signal and an instantaneous current signal.

3. The method according to claim 1, characterized in that, The step of shifting the instantaneous electrical signal by a preset angle based on an all-pass filter to obtain the instantaneous orthogonal electrical signal includes: Obtain the transfer function of the all-pass filter; The difference equation is obtained by performing a bilinear transformation on the transfer function; The instantaneous electrical signal is phase-shifted by a preset angle based on the difference equation to obtain the instantaneous orthogonal electrical signal.

4. The method according to claim 1, characterized in that, The step of determining the positive-sequence component and negative-sequence component of the instantaneous electrical quantity signal based on the instantaneous electrical quantity signal and the instantaneous orthogonal electrical quantity signal includes: Acquire historical electrical quantity signals and historical orthogonal electrical quantity signals in a three-phase power grid; Determine the correspondence between the instantaneous orthogonal electrical signal and the historical electrical signal, the historical orthogonal electrical signal and the instantaneous electrical signal, and obtain the positive sequence component and negative sequence component of the instantaneous electrical signal based on the correspondence.

5. The method according to claim 4, characterized in that, Determining the correspondence between the instantaneous orthogonal energy signal and the historical energy signal, and between the historical orthogonal energy signal and the instantaneous energy signal, includes: Based on the difference equation corresponding to the all-pass filter, the historical energy signal, the historical orthogonal energy signal, and the instantaneous energy signal are used as input variables, and the instantaneous orthogonal energy signal is used as the output variable; The input variables and the output variables are fitted to obtain the correspondence.

6. The method according to claim 4, characterized in that, After obtaining the positive-sequence and negative-sequence components of the instantaneous electrical signal according to the correspondence, the method further includes: The positive-sequence component and the negative-sequence component are subjected to Clarke transform and Park transform to obtain control signals for error analysis of the three-phase power grid.

7. A positive and negative sequence charge separation device, characterized in that, The steps are configured to implement the method of any one of claims 1 to 6.

8. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When executed by a processor, the program instructions implement the steps of the method according to any one of claims 1 to 6.

10. A computer program product, characterized in that, It includes a computer program, which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 6.

Images