Three-phase circuit voltage sag detection method, device and equipment and storage medium

Abstract

The invention relates to a three-phase circuit voltage sag detection method and device, equipment and a storage medium. The method comprises the following steps: acquiring a voltage direct-axis component and a voltage quadrature-axis component of a three-phase voltage of a three-phase circuit in a positive-sequence rotation two-phase coordinate system; determining a positive sequence amplitude, a positive sequence phase angle, a negative sequence amplitude and a negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component; determining a zero-sequence amplitude and a zero-sequence phase angle based on the three-phase voltage; determining a first amplitude and a first phase angle of the first phase voltage, a second amplitude and a second phase angle of the second phase voltage, and a third amplitude and a third phase angle of the third phase voltage based on the positive sequence amplitude, the positive sequence phase angle, the negative sequence amplitude, the negative sequence phase angle, the zero sequence amplitude and the zero sequence phase angle; and determining a voltage sag detection result of the three-phase circuit by using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude and the third phase angle. By adopting the method, the voltage sag detection efficiency of the three-phase circuit can be improved.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a method, apparatus, computer equipment, storage medium and computer program product for detecting voltage sags in a three-phase circuit. Background Technology

[0002] Power quality problems are divided into two categories: variable and event-related. Variable problems include continuous phenomena such as voltage imbalance, harmonic voltage and current distortion, and voltage fluctuations. Event-related problems include sudden phenomena such as voltage dips, short-term interruptions, and undervoltage. Among these, voltage dips occur frequently and are more harmful.

[0003] In traditional techniques, the voltage sag detection result of a three-phase circuit is determined by the result obtained from the "double dq transformation (direct-quadrature transformation) method". The entire process involves a large amount of calculation, resulting in low efficiency of voltage sag detection in three-phase circuits. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for detecting three-phase circuit voltage sags that can improve the detection efficiency of three-phase circuit voltage sags, in order to address the above-mentioned technical problems.

[0005] Firstly, this application provides a method for detecting voltage sags in a three-phase circuit. The method includes:

[0006] Obtain the direct-axis and quadrature-axis components of the three-phase voltages in a positive-sequence rotating two-phase coordinate system; the three-phase voltages include the first-phase voltage, the second-phase voltage, and the third-phase voltage.

[0007] The positive sequence magnitude, positive sequence phase angle, negative sequence magnitude, and negative sequence phase angle are determined based on the voltage direct-axis component and the voltage quadrature-axis component.

[0008] Determine the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage;

[0009] Based on the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle, determine the first amplitude and first phase angle of the first phase voltage, the second amplitude and second phase angle of the second phase voltage, and the third amplitude and third phase angle of the third phase voltage;

[0010] The voltage sag detection results of the three-phase circuit are determined using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude, and the third phase angle.

[0011] In some exemplary embodiments, determining the positive-sequence magnitude and positive-sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component includes:

[0012] The voltage direct-axis component and voltage quadrature-axis component are input to a DC filter to obtain the positive-sequence direct-axis component and positive-sequence quadrature-axis component of the positive-sequence component in the positive-sequence rotating two-phase coordinate system.

[0013] The positive sequence magnitude and positive sequence phase angle are determined based on the positive sequence direct axis component and the positive sequence quadrature axis component.

[0014] In some exemplary embodiments, determining the negative sequence magnitude and negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component includes:

[0015] The voltage direct-axis component and voltage quadrature-axis component are input to the AC filter to obtain the AC direct-axis component and AC quadrature-axis component of the negative-sequence component in the positive-sequence rotating two-phase coordinate system.

[0016] By performing a negative-sequence coordinate rotation transformation on the AC direct-axis component and the AC quadrature-axis component, the negative-sequence direct-axis component and the negative-sequence quadrature-axis component in the negative-sequence rotating two-phase coordinate system are obtained.

[0017] The negative sequence magnitude and negative sequence phase angle are determined based on the negative sequence direct axis component and the negative sequence quadrature axis component.

[0018] In some exemplary embodiments, determining the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage includes:

[0019] The average voltage is obtained by averaging the first phase voltage, the second phase voltage, and the third phase voltage.

[0020] By projecting the average voltage onto a stationary two-phase coordinate system, the zero-sequence real-axis component and the zero-sequence imaginary-axis component are obtained.

[0021] The zero-sequence amplitude and zero-sequence phase angle are determined based on the zero-sequence real axis component and the zero-sequence imaginary axis component.

[0022] In some exemplary embodiments, the voltage sag detection result of a three-phase circuit is determined using a first amplitude, a first phase angle, a second amplitude, a second phase angle, a third amplitude, and a third phase angle, including:

[0023] The first amplitude, the second amplitude, and the third amplitude are compared to obtain the first comparison result;

[0024] Determine the first difference between the first phase angle and the second phase angle, and the second difference between the second phase angle and the third phase angle;

[0025] The first difference and the second difference are compared with the difference threshold to obtain the second comparison result;

[0026] Based on the first comparison result and the second comparison result, the voltage sag detection result of the three-phase circuit is determined.

[0027] In some exemplary embodiments, the voltage sag detection result of the three-phase circuit is determined based on the first comparison result and the second comparison result, including:

[0028] If the first comparison result is that the first amplitude, the second amplitude, and the third amplitude are not equal, and the second comparison result is that at least one of the first difference and the second difference is not equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined to be a voltage sag.

[0029] Secondly, this application also provides a three-phase circuit voltage sag detection device. The device includes:

[0030] The acquisition module is used to acquire the direct-axis and quadrature-axis components of the three-phase voltages in a positive-sequence rotating two-phase coordinate system; the three-phase voltages include the first-phase voltage, the second-phase voltage, and the third-phase voltage.

[0031] The first determining module is used to determine the positive sequence magnitude, positive sequence phase angle, negative sequence magnitude, and negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component;

[0032] The second determining module is used to determine the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage;

[0033] The calculation module is used to determine the first amplitude and first phase angle of the first phase voltage, the second amplitude and second phase angle of the second phase voltage, and the third amplitude and third phase angle of the third phase voltage based on the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle.

[0034] The detection module is used to determine the voltage sag detection result of the three-phase circuit using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude, and the third phase angle.

[0035] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods in the first aspect.

[0036] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods in the first aspect.

[0037] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of any of the methods in the first aspect.

[0038] The aforementioned three-phase circuit voltage sag detection method, apparatus, computer equipment, storage medium, and computer program product acquire the direct-axis and quadrature-axis components of the three-phase voltage in a positive-sequence rotating two-phase coordinate system. The three-phase voltage includes the first-phase voltage, the second-phase voltage, and the third-phase voltage. Based on the direct-axis and quadrature-axis components, the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, and negative-sequence phase angle are determined. Based on the three-phase voltage, the zero-sequence amplitude and zero-sequence phase angle are determined. Based on the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle, the first amplitude and first phase angle of the first-phase voltage, the second amplitude and second phase angle of the second-phase voltage, and the third amplitude and third phase angle of the third-phase voltage are determined. Using the first amplitude, first phase angle, second amplitude, second phase angle, third amplitude, and third phase angle, the voltage sag detection result of the three-phase circuit is determined. By acquiring the direct-axis and quadrature-axis components of the three-phase voltage in a positive-sequence rotating two-phase coordinate system, the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle are calculated sequentially. Based on these values, the amplitude and phase angle of each phase voltage are reconstructed, enabling the detection of voltage sags in the three-phase circuit. Compared to the dual dq transform method, this method determines the positive-sequence, negative-sequence, and zero-sequence components using only a single rotating coordinate system and its transformation, reducing the computational load and improving the efficiency of three-phase voltage sag detection. Furthermore, in scenarios with embedded microprocessors or limited computing power, this three-phase voltage sag detection method significantly improves the efficiency and real-time performance of three-phase voltage sag detection while maintaining its accuracy and reliability. Attached Figure Description

[0039] Figure 1 This is a diagram illustrating the application environment of a three-phase circuit voltage sag detection method in one embodiment.

[0040] Figure 2 This is a flowchart illustrating a three-phase circuit voltage sag detection method in one embodiment;

[0041] Figure 3 This is a flowchart illustrating the steps for determining the positive sequence magnitude and positive sequence phase angle in one embodiment;

[0042] Figure 4 This is a flowchart illustrating the steps for determining the negative sequence magnitude and negative sequence phase angle in one embodiment;

[0043] Figure 5 This is a flowchart illustrating a three-phase circuit voltage sag detection method in another embodiment;

[0044] Figure 6 This is a structural block diagram of a three-phase circuit voltage sag detection device in one embodiment;

[0045] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] The three-phase circuit voltage sag detection method provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104 or placed on a cloud or other network server. Both the terminal and the server can be used independently to execute the three-phase circuit voltage sag detection method provided in this embodiment. The terminal and server can also be used collaboratively to execute the three-phase circuit voltage sag detection method provided in this embodiment. For example, terminal 102 acquires the direct-axis and quadrature-axis components of the three-phase voltages in a positive-sequence rotating two-phase coordinate system; the three-phase voltages include the first-phase voltage, the second-phase voltage, and the third-phase voltage; based on the direct-axis and quadrature-axis components, it determines the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, and negative-sequence phase angle; based on the three-phase voltages, it determines the zero-sequence amplitude and zero-sequence phase angle; based on the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle, it determines the first amplitude and first phase angle of the first-phase voltage, the second amplitude and second phase angle of the second-phase voltage, and the third amplitude and third phase angle of the third-phase voltage; using the first amplitude, first phase angle, second amplitude, second phase angle, third amplitude, and third phase angle, it determines the voltage sag detection result of the three-phase circuit. Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices; IoT devices can be smart speakers, smart TVs, smart air conditioners, smart vehicle devices, etc. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. Server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers.

[0048] In some exemplary embodiments, such as Figure 2 As shown, a method for detecting voltage sags in a three-phase circuit is provided. This method can be applied to computer equipment, which can be a terminal or a server. The method can be executed independently by the terminal or server, or through interaction between the terminal and the server. This embodiment uses the application of this method to a computer device as an example for illustration, including steps 202 to 210.

[0049] Step 202: Obtain the direct-axis component and quadrature-axis component of the three-phase voltage in the positive-sequence rotating two-phase coordinate system; the three-phase voltage includes the first-phase voltage, the second-phase voltage, and the third-phase voltage.

[0050] A three-phase circuit refers to a power system consisting of three phase lines, typically phases a, b, and c, each phase differing by 120° electrical angle. Three-phase voltage refers to the voltage of each of the three phase lines in a three-phase circuit, namely the first-phase voltage, the second-phase voltage, and the third-phase voltage. Under normal voltage conditions, the voltage amplitudes of the first-phase, second-phase, and third-phase voltages are equal, with phase angles differing by 120° sequentially. The positive-sequence rotating two-phase coordinate system is a dq coordinate system established with the positive-sequence component of the grid fundamental frequency rotated around its phase angle as a reference. It consists of a direct axis (d-axis) and a quadrature axis (q-axis). The direct axis is in phase with the positive-sequence voltage, and the quadrature axis intersects the direct axis. The direct-axis voltage component is the component of the three-phase voltage projected onto the d-axis in the positive-sequence rotating coordinate system, reflecting the magnitude of the voltage in the synchronous reference direction. The quadrature-axis voltage component is the component of the three-phase voltage projected onto the q-axis in the positive-sequence rotating coordinate system, reflecting the magnitude of the voltage in a direction orthogonal to the positive-sequence reference.

[0051] For example, a computer device acquires the direct-axis and quadrature-axis components of the three-phase voltages of a three-phase circuit in a positive-sequence rotating two-phase coordinate system; the three-phase voltages include the first-phase voltage, the second-phase voltage, and the third-phase voltage.

[0052] In some exemplary embodiments, the computer device acquires the three-phase voltage of a three-phase circuit, performs dq transformation on the three-phase voltage, and obtains the voltage direct-axis component and voltage quadrature-axis component in a positive-sequence rotating two-phase coordinate system.

[0053] In some exemplary embodiments, the calculation formulas for the direct-axis component and the quadrature-axis component of the voltage are as follows:

[0054] Formula (1)

[0055] Among them, among them, This is the voltage of the first phase; This is the voltage of the second phase; This is the voltage of the third phase; The rotation reference angle is usually taken as the phase angle of the positive sequence component; The voltage is the direct-axis component; This represents the quadrature-axis component of the voltage.

[0056] Step 204: Determine the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, and negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component.

[0057] In this context, positive sequence amplitude refers to the amplitude of the positive sequence component of the three-phase voltage, i.e., the magnitude of the positive sequence voltage obtained from the three-phase voltage in symmetrical component theory, reflecting the strength of the normal balance component in the system. Positive sequence phase angle refers to the phase position of the positive sequence component in time, determining the temporal position of the voltage waveform. Negative sequence amplitude refers to the amplitude of the negative sequence component of the three-phase voltage, reflecting the degree of three-phase voltage imbalance. Negative sequence phase angle refers to the phase of the negative sequence component; its deviation from the positive sequence phase angle characterizes the phase characteristics of voltage imbalance.

[0058] For example, the computer device determines the positive sequence amplitude and positive sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component, and determines the negative sequence amplitude and negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component.

[0059] Step 206: Determine the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage.

[0060] Here, zero-sequence amplitude refers to the amplitude of the zero-sequence component of the three-phase voltage. Zero-sequence phase angle refers to the phase position of the zero-sequence component.

[0061] For example, a computer device determines the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage.

[0062] Step 208: Based on the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle, determine the first amplitude and first phase angle of the first phase voltage, the second amplitude and second phase angle of the second phase voltage, and the third amplitude and third phase angle of the third phase voltage.

[0063] The first amplitude refers to the amplitude of phase a voltage reconstructed based on positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle. The first phase angle refers to the phase angle of phase a voltage reconstructed based on positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle. The second amplitude refers to the amplitude of phase b voltage reconstructed based on positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle. The second phase angle refers to the phase angle of phase b voltage reconstructed based on positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle. The third amplitude refers to the amplitude of phase c voltage reconstructed based on positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle. The third phase angle refers to the phase angle of the c-phase voltage reconstructed based on the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle.

[0064] For example, a computer device determines a first amplitude and a first phase angle of a first phase voltage, a second amplitude and a second phase angle of a second phase voltage, and a third amplitude and a third phase angle of a third phase voltage based on positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle.

[0065] In some exemplary embodiments, the formulas for calculating the first magnitude of the first phase voltage and the first phase angle are as follows:

[0066] Formula (2)

[0067] Formula (3)

[0068] in, This is the first value; The magnitude is positive sequence. Negative magnitude; Zero-order magnitude; The phase angle is in positive order; The phase angle is negative. It is the zero-sequence phase angle.

[0069] In some exemplary embodiments, the formulas for calculating the second magnitude of the second phase voltage and the second phase angle are as follows:

[0070] Formula (4)

[0071] Formula (5)

[0072] in, This is the first value; The magnitude is positive sequence. Negative magnitude; Zero-order magnitude; The phase angle is in positive order; The phase angle is negative. It is the zero-sequence phase angle.

[0073] In some exemplary embodiments, the formulas for calculating the third magnitude and the third phase angle of the third phase voltage are as follows:

[0074] Formula (6)

[0075] Formula (7)

[0076] in, This is the first value; The magnitude is positive sequence. Negative magnitude; Zero-order magnitude; The phase angle is in positive order; The phase angle is negative. It is the zero-sequence phase angle.

[0077] Step 210: Use the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude, and the third phase angle to determine the voltage sag detection result of the three-phase circuit.

[0078] The voltage sag detection result refers to the result obtained from voltage sag detection, which can be either a voltage sag or normal voltage. A voltage sag refers to a significant drop in voltage amplitude within a short period of time in a three-phase circuit (typically dropping to 90%–10% of the rated value), possibly accompanied by a change in phase angle. Normal voltage means that in a three-phase circuit, both the voltage amplitude and phase angle are within the standard allowable range, indicating that no power quality event has occurred in the three-phase circuit.

[0079] For example, the electronic device uses a first amplitude, a first phase angle, a second amplitude, a second phase angle, a third amplitude, and a third phase angle to determine the voltage sag detection result of a three-phase circuit.

[0080] In the aforementioned three-phase circuit voltage sag detection method, the direct-axis and quadrature-axis components of the three-phase voltage in a positive-sequence rotating two-phase coordinate system are obtained. The positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle are calculated sequentially. Based on these values, the amplitude and phase angle of each phase voltage are reconstructed. This allows for the detection of three-phase circuit voltage sags based on the amplitude and phase angle of each phase voltage. Compared to the dual dq transform method, this method determines the positive-sequence, negative-sequence, and zero-sequence components using only a single rotating coordinate system and its transformation, reducing the computational load in the voltage sag detection process and thus improving the efficiency of three-phase circuit voltage sag detection. Furthermore, in scenarios with embedded microprocessors or limited computing power, this three-phase circuit voltage sag detection method can significantly improve the efficiency and real-time performance of three-phase circuit voltage sag detection while maintaining its accuracy and reliability.

[0081] In some exemplary embodiments, such as Figure 3 As shown, based on the voltage direct-axis component and voltage quadrature-axis component, the positive-sequence magnitude and positive-sequence phase angle are determined, including:

[0082] Step 302: Input the voltage direct-axis component and voltage quadrature-axis component into the DC filter to obtain the positive-sequence direct-axis component and positive-sequence quadrature-axis component in the positive-sequence rotating two-phase coordinate system.

[0083] A DC filter is a filter that removes AC components and retains only the DC component of the input signal. A DC filter can be a low-pass filter. The positive-sequence direct-axis component refers to the component of the positive-sequence component along the d-axis in a positive-sequence rotating two-phase coordinate system. The positive-sequence quadrature-axis component refers to the component of the positive-sequence component along the q-axis in a positive-sequence rotating two-phase coordinate system.

[0084] For example, the computer device inputs the voltage direct-axis component and the voltage quadrature-axis component to a low-pass filter to obtain the positive-sequence direct-axis component and the positive-sequence quadrature-axis component in the positive-sequence rotating two-phase coordinate system.

[0085] Step 304: Determine the positive sequence magnitude and positive sequence phase angle based on the positive sequence direct axis component and the positive sequence quadrature axis component.

[0086] For example, a computer device determines the positive sequence magnitude and positive sequence phase angle based on the positive sequence direct axis component and the positive sequence quadrature axis component.

[0087] In some exemplary embodiments, the formulas for calculating the positive sequence magnitude and positive sequence phase angle are as follows:

[0088] Formula (8)

[0089] Formula (9)

[0090] in, The magnitude is positive sequence. These are the positive-order direct-axis components; These are orthogonal axis components; It is the positive sequence phase angle.

[0091] In this embodiment, by inputting the voltage direct-axis component and voltage quadrature-axis component into a DC filter, AC components can be effectively filtered out, retaining only the positive-sequence direct-axis component and positive-sequence quadrature-axis component in the positive-sequence rotating two-phase coordinate system. This allows for accurate calculation of the positive-sequence amplitude and positive-sequence phase angle based on the positive-sequence direct-axis component and positive-sequence quadrature-axis component. Compared to directly calculating the positive-sequence amplitude and positive-sequence phase angle based on the instantaneous voltage, this method avoids the influence of noise, negative-sequence components, and zero-sequence components on the results, improving the accuracy of the positive-sequence amplitude and positive-sequence phase angle, and providing an accurate data foundation for subsequent voltage sag detection.

[0092] In some exemplary embodiments, such as Figure 4 As shown, based on the voltage direct-axis component and voltage quadrature-axis component, the negative-sequence magnitude and negative-sequence phase angle are determined, including:

[0093] Step 402: Input the voltage direct-axis component and voltage quadrature-axis component into the AC filter to obtain the AC direct-axis component and AC quadrature-axis component of the negative-sequence component in the positive-sequence rotating two-phase coordinate system.

[0094] An AC filter is a filter that removes the DC component and retains only the AC component. An AC filter can be a 100Hz Second-Order Generalized Integrator (SOGI). AC filters can filter out the fundamental frequency signal from the input signal without causing phase delay. The AC direct-axis component refers to the AC component of the voltage obtained after processing by the AC filter in the direct-axis direction of the positive-sequence rotating two-phase coordinate system. The AC quadrature-axis component refers to the AC component of the voltage obtained after processing by the AC filter in the quadrature-axis direction of the positive-sequence rotating two-phase coordinate system.

[0095] For example, the computer device inputs the voltage direct-axis component and voltage quadrature-axis component into a 100Hz generalized second-order integral filter to obtain the AC direct-axis component and AC quadrature-axis component of the negative-sequence component in the positive-sequence rotating two-phase coordinate system.

[0096] In one exemplary embodiment, the AC direct-axis component and the AC quadrature-axis component are as follows:

[0097] Formula (10)

[0098] Formula (11)

[0099] in, For AC direct-axis components; is the system transfer function of the AC filter; k is the proportional gain factor of SOGI; ω is the angular frequency of the target fundamental wave (rad / s), which is the reference frequency for the signal processing in SOGI or AC filter. For example, for a three-phase system with a grid fundamental frequency of 50Hz, the negative sequence component will oscillate at a frequency of 2×50Hz=100Hz in the positive sequence dq coordinate system, so here ω=2π×100rad / s; s is the complex frequency variable of the Laplace transform. The voltage is the direct-axis component; For alternating axis components; This represents the quadrature-axis component of the voltage.

[0100] Step 404: Perform negative sequence coordinate rotation transformation on the AC direct axis component and the AC quadrature axis component to obtain the negative sequence direct axis component and the negative sequence quadrature axis component in the negative sequence rotating two-phase coordinate system.

[0101] The negative-sequence coordinate rotation transformation refers to the mathematical transformation that converts the AC components of voltage in the positive-sequence rotating coordinate system to the negative-sequence rotating coordinate system. The negative-sequence direct-axis component refers to the voltage component along the direct axis of the negative-sequence rotating two-phase coordinate system obtained after the negative-sequence coordinate rotation transformation. The negative-sequence cross-axis component refers to the voltage component along the cross-axis of the negative-sequence rotating two-phase coordinate system obtained after the negative-sequence coordinate rotation transformation.

[0102] For example, the computer device performs a negative-sequence coordinate rotation transformation on the AC direct-axis component and the AC quadrature-axis component to obtain the negative-sequence direct-axis component and the negative-sequence quadrature-axis component in the negative-sequence rotating two-phase coordinate system.

[0103] In an exemplary embodiment, the negative-order direct-axis component and the negative-order quadrature-axis component are as follows:

[0104] Formula (12)

[0105] Formula (13)

[0106] in, These are negative-order direct-axis components; For AC direct-axis components; For alternating axis components; The positive sequence component rotates around the reference angle; It is the negative-order cross-axis component.

[0107] Step 406: Determine the negative sequence magnitude and negative sequence phase angle based on the negative sequence direct axis component and the negative sequence quadrature axis component.

[0108] For example, the computer device determines the negative sequence magnitude and negative sequence phase angle based on the negative sequence direct axis component and the negative sequence quadrature axis component.

[0109] In some exemplary embodiments, the formulas for calculating the negative sequence magnitude and negative sequence phase angle are as follows:

[0110] Formula (14)

[0111] Formula (15)

[0112] in, Negative magnitude; These are negative-order direct-axis components; The negative-order cross-axis component; It is a negative phase angle.

[0113] In this embodiment, by inputting the voltage direct-axis component and voltage quadrature-axis component into an AC filter, the AC direct-axis component and AC quadrature-axis component of the negative sequence component in the positive-sequence rotating two-phase coordinate system are effectively extracted. Then, the AC direct-axis component and AC quadrature-axis component are converted into negative-sequence direct-axis component and negative-sequence quadrature-axis component in the negative-sequence rotating two-phase coordinate system through negative-sequence coordinate rotation transformation. Both the negative-sequence direct-axis component and the negative-sequence quadrature-axis component are DC quantities. Then, the negative-sequence direct-axis component and the negative-sequence quadrature-axis component are used to accurately calculate the negative-sequence amplitude and the negative-sequence phase angle, avoiding interference from noise, positive-sequence component and zero-sequence component, improving the accuracy of negative-sequence amplitude and negative-sequence phase angle, and providing a reliable negative-sequence data foundation for subsequent three-phase circuit voltage sag detection.

[0114] In some exemplary embodiments, determining the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage includes:

[0115] The first phase voltage, the second phase voltage, and the third phase voltage are averaged to obtain the average voltage. The average voltage is projected onto a stationary two-phase coordinate system to obtain the zero-sequence real axis component and the zero-sequence imaginary axis component. Based on the zero-sequence real axis component and the zero-sequence imaginary axis component, the zero-sequence amplitude and the zero-sequence phase angle are determined.

[0116] The average voltage refers to the voltage value obtained by taking the arithmetic mean of the first-phase voltage, the second-phase voltage, and the third-phase voltage. The stationary two-phase coordinate system refers to the αβ two-phase coordinate system fixed in a spatial stationary reference frame, used to project the three-phase voltage into two-dimensional components. The stationary two-phase coordinate system consists of a real axis (α-axis) and an imaginary axis (β-axis). The zero-sequence real axis component refers to the component of the zero-sequence voltage along the real axis of the stationary two-phase coordinate system. The zero-sequence imaginary axis component refers to the component of the zero-sequence voltage along the imaginary axis of the stationary two-phase coordinate system.

[0117] For example, the computer device averages the first phase voltage, the second phase voltage, and the third phase voltage to obtain an average voltage, projects the average voltage onto a stationary two-phase coordinate system to obtain the zero-sequence real axis component and the zero-sequence imaginary axis component; and determines the zero-sequence amplitude and the zero-sequence phase angle based on the zero-sequence real axis component and the zero-sequence imaginary axis component.

[0118] In some exemplary embodiments, the calculation formulas for the zero-sequence real axis component and the zero-sequence imaginary axis component are as follows:

[0119] Formula (16)

[0120] Formula (17)

[0121] Formula (18)

[0122] in, The zero-sequence real-axis component; The zero-order imaginary axis component; This is the rotation coordinate transformation matrix; Average voltage Phase lag The phase angle is 90°. It can be done The derivative is calculated, which corresponds to the difference calculation in embedded microprocessors.

[0123] In some exemplary embodiments, the formulas for calculating the zero-sequence magnitude and zero-sequence phase angle are as follows:

[0124] Formula (19)

[0125] Formula (20)

[0126] in, Zero-order magnitude; The zero-sequence direct-axis component; The zero-order cross-axis component; It is the zero-sequence phase angle.

[0127] In this embodiment, by averaging the three-phase voltage and projecting it onto a stationary two-phase coordinate system, the zero-sequence real-axis component and the zero-sequence imaginary-axis component can be obtained. Since both the zero-sequence real-axis component and the zero-sequence imaginary-axis component are DC components, the calculation process of the zero-sequence amplitude and the zero-sequence phase angle can be simplified. Compared with the traditional method that requires complex calculations to extract the zero-sequence component, the above method can determine the zero-sequence amplitude and the zero-sequence phase angle in a simpler way, reducing the amount of calculation and improving the efficiency and accuracy of the zero-sequence component calculation. This provides a more accurate and reliable data basis for the three-phase circuit voltage sag detection process, and further improves the real-time performance and accuracy of voltage sag detection.

[0128] In some exemplary embodiments, the voltage sag detection result of a three-phase circuit is determined using a first amplitude, a first phase angle, a second amplitude, a second phase angle, a third amplitude, and a third phase angle, including:

[0129] The first amplitude, the second amplitude, and the third amplitude are compared to obtain the first comparison result; the first difference between the first phase angle and the second phase angle are determined, and the second difference between the second phase angle and the third phase angle is determined; the first difference and the second difference are compared with the difference threshold to obtain the second comparison result; based on the first comparison result and the second comparison result, the voltage sag detection result of the three-phase circuit is determined.

[0130] The first comparison result refers to the comparison obtained by comparing the first amplitude, second amplitude, and third amplitude, used to determine whether there is a significant difference in the three-phase voltage amplitude. The first difference refers to the difference between the first phase angle and the second phase angle, used to reflect the phase angle difference between two adjacent phase voltages. The second difference refers to the difference between the second phase angle and the third phase angle, used to reflect the phase angle difference between another set of adjacent phase voltages. The difference threshold is a preset threshold used to determine whether the phase angle difference is abnormal. When the phase angle difference exceeds this threshold, it indicates that the three-phase voltage may be unbalanced or there may be a voltage sag. The second comparison result refers to the comparison obtained by comparing the first difference and the second difference with the difference threshold.

[0131] For example, the computer device compares a first amplitude, a second amplitude, and a third amplitude to obtain a first comparison result, determines a first difference between a first phase angle and a second phase angle, and a second difference between a second phase angle and a third phase angle, compares the first difference and the second difference with a difference threshold to obtain a second comparison result, and determines the voltage sag detection result of the three-phase circuit based on the first comparison result and the second comparison result.

[0132] In this embodiment, by comparing the amplitudes of the three-phase voltages and combining the phase angle difference with a difference threshold for comprehensive judgment, both voltage amplitude anomalies and phase angle anomalies can be considered simultaneously when detecting voltage sags. Specifically, the first comparison result is used to detect voltage amplitude imbalances, and the second comparison result is used to identify whether the phase angle offset exceeds the normal range. This avoids misjudgments caused by relying on a single indicator. The combination of both significantly improves the accuracy and reliability of voltage sag detection. Furthermore, the method has a simple calculation process, involving only amplitude comparison and phase angle difference comparison, making it suitable for embedded microprocessor implementation and improving real-time performance while ensuring detection accuracy.

[0133] In some exemplary embodiments, the voltage sag detection result of the three-phase circuit is determined based on the first comparison result and the second comparison result, including:

[0134] If the first comparison result is that the first amplitude, the second amplitude, and the third amplitude are not equal, and the second comparison result is that at least one of the first difference and the second difference is not equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined to be a voltage sag.

[0135] For example, if the first comparison result is that the first amplitude, the second amplitude, and the third amplitude are not equal, and the second comparison result is that at least one of the first difference and the second difference is not equal to the difference threshold, the computer device determines that the voltage sag detection result of the three-phase circuit is a voltage sag.

[0136] In some exemplary embodiments, when the first comparison result is that the first amplitude, the second amplitude, and the third amplitude are equal, and the second comparison result is that both the first difference and the second difference are equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined to be normal.

[0137] In this embodiment, when the first comparison result shows that the three-phase voltage amplitudes are not equal and at least one phase angle difference in the second comparison result is not equal to the difference threshold, a voltage sag is determined to have occurred. This achieves joint discrimination of amplitude anomaly and phase angle anomaly, ensuring that the voltage sag detection results can cover two typical power quality problems: voltage imbalance and phase shift. Compared with methods that rely solely on a single indicator (amplitude or phase angle) for judgment, this method can effectively reduce the probability of false detection and missed detection, and improve the accuracy and robustness of voltage sag detection.

[0138] In an exemplary embodiment, a flowchart of a three-phase circuit voltage sag detection method is shown below. Figure 5 The following are included:

[0139] Computer equipment obtains the three-phase voltage (i.e., the first phase voltage) of a three-phase circuit. Second phase voltage and the third phase voltage Using formula (1), the three-phase voltage is transformed by dq to obtain the direct-axis components of the three-phase voltage in the positive-sequence rotating two-phase coordinate system (i.e., ) and voltage quadrature axis components (i.e. ).

[0140] The computer equipment inputs the voltage direct-axis component and voltage quadrature-axis component to a low-pass filter to obtain the positive-sequence direct-axis component of the positive-sequence component in the positive-sequence rotating two-phase coordinate system (i.e., ) and orthogonal axis components (i.e. Substituting the positive sequence direct axis component and the positive sequence quadrature axis component into formulas (8) and (9), the positive sequence amplitude (i.e.) is calculated. ) and positive sequence phase angle (i.e. ).

[0141] The computer equipment inputs the voltage direct-axis component and voltage quadrature-axis component into a 100Hz generalized second-order integrator filter, and uses formulas (10) and (11) to calculate the AC direct-axis component of the negative-sequence component in the positive-sequence rotating two-phase coordinate system (i.e., ) and AC cross-axis components (i.e. ); Perform negative-sequence coordinate rotation transformation on the AC direct-axis component and the AC quadrature-axis component, and use formulas (12) and (13) to calculate the negative-sequence direct-axis component of the negative-sequence component in the negative-sequence rotated two-phase coordinate system (i.e. ) and negative order cross axis components (i.e. Substituting the negative sequence direct axis component and the negative sequence quadrature axis component into formulas (14) and (15), the negative sequence amplitude (i.e., ) and negative sequence phase angle (i.e. ).

[0142] The computer equipment averages the first-phase voltage, the second-phase voltage, and the third-phase voltage to obtain the average voltage (i.e., ),pass The derivative calculation yields ,Will and Substituting into formula (16) (i.e., performing αβ transformation), we obtain the zero-sequence real axis component (i.e. ) and zero-sequence imaginary axis components (i.e. Substitute the zero-sequence real axis component and the zero-sequence imaginary axis component into formulas (19) and (20) to calculate and determine the zero-sequence amplitude (i.e. ) and zero-sequence phase angle (i.e. ).

[0143] The computer equipment substitutes the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude, and zero sequence phase angle into formulas (2) and (3) to obtain the first amplitude of the first phase voltage (i.e., ) and the first phase angle (i.e. Substituting the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle into formulas (4) and (5), we obtain the second amplitude of the second phase voltage (i.e., ) and the second phase angle (i.e. Substituting the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle into formulas (6) and (7), we obtain the second amplitude of the second phase voltage (i.e., ) and the second phase angle (i.e. ).

[0144] The computer equipment compares the first amplitude, the second amplitude, and the third amplitude to obtain a first comparison result, determines the first difference between the first phase angle and the second phase angle, and the second difference between the second phase angle and the third phase angle. The first difference and the second difference are then compared with a difference threshold to obtain a second comparison result. If the first comparison result shows that the first amplitude, the second amplitude, and the third amplitude are not equal, and the second comparison result shows that at least one of the first difference and the second difference is not equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined to be a voltage sag. If the first comparison result shows that the first amplitude, the second amplitude, and the third amplitude are equal, and the second comparison result shows that both the first difference and the second difference are equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined to be a normal voltage.

[0145] By acquiring the direct-axis and quadrature-axis components of the three-phase voltage in a positive-sequence rotating two-phase coordinate system, the positive-sequence amplitude, positive-sequence phase angle, negative-sequence amplitude, negative-sequence phase angle, zero-sequence amplitude, and zero-sequence phase angle are calculated sequentially. Based on these values, the amplitude and phase angle of each phase voltage are reconstructed, enabling the detection of voltage sags in the three-phase circuit. Compared to the dual dq transform method, this method determines the positive-sequence, negative-sequence, and zero-sequence components using only a single rotating coordinate system and its transformation, reducing the computational load and improving the efficiency of three-phase voltage sag detection. Furthermore, in scenarios with embedded microprocessors or limited computing power, this three-phase voltage sag detection method significantly improves the efficiency and real-time performance of three-phase voltage sag detection while maintaining its accuracy and reliability.

[0146] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0147] Based on the same inventive concept, this application also provides a three-phase circuit voltage sag detection device for implementing the three-phase circuit voltage sag detection method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the three-phase circuit voltage sag detection device provided below can be found in the limitations of the three-phase circuit voltage sag detection method described above, and will not be repeated here.

[0148] In some exemplary embodiments, such as Figure 6 As shown, a three-phase circuit voltage sag detection device is provided, comprising: an acquisition module 602, a first determination module 604, a second determination module 606, a calculation module 608, and a detection module 610, wherein:

[0149] The acquisition module 602 is used to acquire the direct-axis component and quadrature-axis component of the three-phase voltage in a positive-sequence rotating two-phase coordinate system of a three-phase circuit; the three-phase voltage includes the first-phase voltage, the second-phase voltage and the third-phase voltage;

[0150] The first determining module 604 is used to determine the positive sequence magnitude, positive sequence phase angle, negative sequence magnitude, and negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component;

[0151] The second determining module 606 is used to determine the zero-sequence amplitude and zero-sequence phase angle based on the three-phase voltage;

[0152] The calculation module 608 is used to determine the first amplitude and first phase angle of the first phase voltage, the second amplitude and second phase angle of the second phase voltage, and the third amplitude and third phase angle of the third phase voltage based on the positive sequence amplitude, positive sequence phase angle, negative sequence amplitude, negative sequence phase angle, zero sequence amplitude and zero sequence phase angle.

[0153] The detection module 610 is used to determine the voltage sag detection result of the three-phase circuit using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude, and the third phase angle.

[0154] In some exemplary embodiments, the first determining module 604 is further configured to: input the voltage direct-axis component and the voltage quadrature-axis component to a DC filter to obtain the positive-sequence direct-axis component and the positive-sequence quadrature-axis component in the positive-sequence rotating two-phase coordinate system; and determine the positive-sequence amplitude and the positive-sequence phase angle based on the positive-sequence direct-axis component and the positive-sequence quadrature-axis component.

[0155] In some exemplary embodiments, the first determining module 604 is further configured to: input the voltage direct-axis component and the voltage quadrature-axis component to the AC filter to obtain the AC direct-axis component and the AC quadrature-axis component of the negative-sequence component in the positive-sequence rotating two-phase coordinate system; perform a negative-sequence coordinate rotation transformation on the AC direct-axis component and the AC quadrature-axis component to obtain the negative-sequence direct-axis component and the negative-sequence quadrature-axis component of the negative-sequence component in the negative-sequence rotating two-phase coordinate system; and determine the negative-sequence amplitude and the negative-sequence phase angle based on the negative-sequence direct-axis component and the negative-sequence quadrature-axis component.

[0156] In some exemplary embodiments, the second determining module 606 is further configured to: average the first phase voltage, the second phase voltage, and the third phase voltage to obtain an average voltage; project the average voltage onto a stationary two-phase coordinate system to obtain a zero-sequence real axis component and a zero-sequence imaginary axis component; and determine the zero-sequence amplitude and the zero-sequence phase angle based on the zero-sequence real axis component and the zero-sequence imaginary axis component.

[0157] In some exemplary embodiments, the detection module 610 is further configured to: compare a first amplitude, a second amplitude, and a third amplitude to obtain a first comparison result; determine a first difference between a first phase angle and a second phase angle, and a second difference between a second phase angle and a third phase angle; compare the first difference and the second difference with a difference threshold to obtain a second comparison result; and determine the voltage sag detection result of the three-phase circuit based on the first comparison result and the second comparison result.

[0158] In some exemplary embodiments, the detection module 610 is further configured to: determine the voltage sag detection result of the three-phase circuit as a voltage sag when the first comparison result is that the first amplitude, the second amplitude and the third amplitude are not equal, and the second comparison result is that at least one of the first difference and the second difference is not equal to the difference threshold.

[0159] Each module in the aforementioned three-phase circuit voltage sag detection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0160] In some exemplary embodiments, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a three-phase circuit voltage sag detection method. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0161] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0162] In some exemplary embodiments, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0163] In some exemplary embodiments, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above-described method embodiments.

[0164] In some exemplary embodiments, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0165] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0166] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0167] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0168] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method of three-phase circuit voltage sag detection, characterized by, The method comprises: obtaining a voltage direct-axis component and a voltage cross-axis component of three-phase voltages of a three-phase circuit in a positive sequence rotating two-phase coordinate system; the three-phase voltages comprise a first-phase voltage, a second-phase voltage and a third-phase voltage; determining a positive sequence amplitude, a positive sequence phase angle, a negative sequence amplitude and a negative sequence phase angle based on the voltage direct-axis component and the voltage cross-axis component; determining a zero sequence amplitude and a zero sequence phase angle based on the three-phase voltages; determining a first amplitude and a first phase angle of the first-phase voltage, a second amplitude and a second phase angle of the second-phase voltage, and a third amplitude and a third phase angle of the third-phase voltage based on the positive sequence amplitude, the positive sequence phase angle, the negative sequence amplitude, the negative sequence phase angle, the zero sequence amplitude and the zero sequence phase angle; determining a voltage sag detection result of the three-phase circuit using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude and the third phase angle.

2. The method of claim 1, wherein, The determination of the positive sequence amplitude and the positive sequence phase angle based on the voltage direct-axis component and the voltage cross-axis component comprises: inputting the voltage direct-axis component and the voltage cross-axis component into a direct-current filter to obtain a positive sequence direct-axis component and a positive sequence cross-axis component of a positive sequence component in the positive sequence rotating two-phase coordinate system; determining the positive sequence amplitude and the positive sequence phase angle based on the positive sequence direct-axis component and the positive sequence cross-axis component.

3. The method of claim 1, wherein, The determination of the negative sequence amplitude and the negative sequence phase angle based on the voltage direct-axis component and the voltage cross-axis component comprises: inputting the voltage direct-axis component and the voltage cross-axis component into an alternating-current filter to obtain an alternating-current direct-axis component and an alternating-current cross-axis component of a negative sequence component in the positive sequence rotating two-phase coordinate system; performing a negative sequence coordinate rotation transformation on the alternating-current direct-axis component and the alternating-current cross-axis component to obtain a negative sequence direct-axis component and a negative sequence cross-axis component of the negative sequence component in a negative sequence rotating two-phase coordinate system; determining the negative sequence amplitude and the negative sequence phase angle based on the negative sequence direct-axis component and the negative sequence cross-axis component.

4. The method of claim 1, wherein, The determination of the zero sequence amplitude and the zero sequence phase angle based on the three-phase voltages comprises: averaging the first-phase voltage, the second-phase voltage and the third-phase voltage to obtain an average voltage; projecting the average voltage into a stationary two-phase coordinate system to obtain a zero sequence real-axis component and a zero sequence imaginary-axis component; determining the zero sequence amplitude and the zero sequence phase angle based on the zero sequence real-axis component and the zero sequence imaginary-axis component.

5. The method of claim 1, wherein, The determination of the voltage sag detection result of the three-phase circuit using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude and the third phase angle comprises: comparing the first amplitude, the second amplitude and the third amplitude to obtain a first comparison result; determining a first difference value between the first phase angle and the second phase angle, and a second difference value between the second phase angle and the third phase angle; comparing the first difference value and the second difference value with a difference threshold to obtain a second comparison result; determining the voltage sag detection result of the three-phase circuit based on the first comparison result and the second comparison result.

6. The method of claim 5, wherein, The determining, based on the first comparison result and the second comparison result, of a voltage sag detection result of the three-phase circuit comprises: In a case where the first comparison result is that the first amplitude, the second amplitude and the third amplitude are not equal, and the second comparison result is that at least one of the first difference and the second difference is not equal to the difference threshold, the voltage sag detection result of the three-phase circuit is determined as a voltage sag.

7. A three-phase circuit voltage sag detection apparatus characterized by comprising: The apparatus comprises: An obtaining module configured to obtain a voltage direct-axis component and a voltage quadrature-axis component of a three-phase voltage of a three-phase circuit in a positive sequence rotating two-phase coordinate system, the three-phase voltage comprising a first-phase voltage, a second-phase voltage and a third-phase voltage; A first determining module configured to determine a positive sequence amplitude, a positive sequence phase angle, a negative sequence amplitude and a negative sequence phase angle based on the voltage direct-axis component and the voltage quadrature-axis component; A second determining module configured to determine a zero sequence amplitude and a zero sequence phase angle based on the three-phase voltage; A calculating module configured to determine a first amplitude and a first phase angle of the first-phase voltage, a second amplitude and a second phase angle of the second-phase voltage, and a third amplitude and a third phase angle of the third-phase voltage based on the positive sequence amplitude, the positive sequence phase angle, the negative sequence amplitude, the negative sequence phase angle, the zero sequence amplitude and the zero sequence phase angle; A detecting module configured to determine a voltage sag detection result of the three-phase circuit using the first amplitude, the first phase angle, the second amplitude, the second phase angle, the third amplitude and the third phase angle.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor, when executing the computer program, implements the steps of the method of any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 6.

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

Images