Connection phase sequence identification method, device and equipment of current transformer and storage medium

Abstract

The application discloses a wiring phase sequence identification method, device and equipment of a current transformer and a storage medium, and belongs to the technical field of wiring phase sequence identification. The method first inputs a capacitor in a main loop of a power distribution device, synchronously collects voltage and current signals by a reactive power compensation controller, extracts a power frequency fundamental wave component through analog-digital conversion and frequency domain conversion, and calculates a phase difference between the fundamental wave voltage and the fundamental wave current. Then, the absolute value of the phase difference and the absolute value of the difference between the preset reference angle are obtained, and the CT wiring phase sequence is judged to be correct or incorrect in combination with a preset error threshold. The application uses a capacitor to generate a fixed phase test signal, eliminates the determination ambiguity caused by the unknown load power factor angle, is compatible with various wiring topologies such as common compensation and separate compensation, does not need additional hardware, can accurately identify the CT phase error problem in all working conditions, reduces the on-site debugging difficulty, and guarantees the stable operation of the reactive power compensation device.

Description

Technical Field

[0001] This application belongs to the field of wiring phase sequence identification technology, and particularly relates to a method, device, equipment and storage medium for identifying the wiring phase sequence of a current transformer. Background Technology

[0002] The reactive power compensation controller needs to collect the load current of each phase through the current transformer (CT). The phase sequence and wiring matching of the CT directly determine whether the compensation calculation logic is accurate. If the phase sequence of the CT is incorrect or the phases are reversed, the power factor calculation and reactive power deficit measurement of the reactive power compensation controller will be completely distorted, resulting in frequent capacitor switching, over-compensation and under-compensation, compensation failure, and in severe cases, capacitor overcurrent damage and grid harmonic amplification.

[0003] The current mainstream automatic phase sequence identification method for reactive power compensation controllers in the industry relies on collecting the voltage and current signals of the natural load on site, and determining the CT wiring relationship by calculating the phase difference between the voltage and the load current. The measured phase difference of the reactive power compensation controller is composed of two superimposed parts: one is the fixed phase offset caused by the CT wiring method, and the other is the inherent power factor angle of the on-site load.

[0004] This traditional identification scheme suffers from an inherent ambiguity that cannot be eradicated. The load power factor angle changes with the type of load and the actual load operation. For example, when the reactive power compensation controller detects a phase difference of 150°, there are two completely opposite possibilities. If the wiring is correct, it will be a 120° phase shift plus a 30° power factor angle for inductive loads; if the wiring is incorrect, it will be a 0° phase shift plus a 150° power factor angle for capacitive loads. Therefore, it is impossible to distinguish the specific wiring status. Summary of the Invention

[0005] The purpose of this application is to provide a method, device, equipment, and storage medium for identifying the wiring phase sequence of a current transformer. By inserting a capacitor into the main wiring circuit of the power distribution device, the fixed phase reference generated by the capacitor is used to identify the wiring phase sequence of the current transformer. This solves the technical problem that the power factor angle of conventional loads changes randomly and cannot accurately distinguish the specific wiring phase sequence of the current transformer, thus achieving accurate identification of the wiring phase sequence of the current transformer.

[0006] To achieve the above objectives, the solution proposed in this application is: In a first aspect, embodiments of this application provide a method for identifying the phase sequence of a current transformer. This method is applied to a power distribution device equipped with a reactive power compensation controller and a current transformer. The method includes: With capacitors connected in the main circuit of the power distribution device, the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller is obtained. Obtain the absolute value of the phase difference and the absolute value of the difference between the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, the current transformer is determined to have an incorrect phase sequence. If the absolute value of the difference is less than the preset error threshold, the current transformer is determined to have a correct phase sequence.

[0007] The method described in the embodiments of this application may also have the following additional technical features: Furthermore, with the capacitor connected in the main circuit, the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller is obtained, including: Obtain the discrete-time sequence of voltage and discrete-time sequence of current of the reactive power compensation controller; Frequency domain transformations were performed on the discrete-time voltage sequence and the discrete-time current sequence to obtain discrete-frequency voltage sequences and discrete-frequency current sequences, respectively. The power frequency components corresponding to the discrete frequency domain sequences of voltage and current are extracted respectively to obtain the complex components of the fundamental voltage and the complex components of the fundamental current. The phase angles of the fundamental voltage and the fundamental current are obtained from the complex components of the fundamental voltage and the complex components of the fundamental current, respectively. The phase difference between the fundamental voltage and the fundamental current is obtained from the phase angle of the fundamental voltage and the phase angle of the fundamental current.

[0008] Furthermore, the voltage discrete-time sequence and current discrete-time sequence of the reactive power compensation controller are obtained, including: The instantaneous voltage and current values ​​of the reactive power compensation controller are synchronously sampled and converted from analog to digital at a preset sampling frequency to obtain discrete digital voltage signals and discrete digital current signals. The discrete voltage digital signal and the discrete current digital signal are stored according to the sampling timing to obtain the discrete time domain sequence of voltage and the discrete time domain sequence of current.

[0009] Furthermore, frequency domain transformations are performed on the discrete-time voltage sequence and the discrete-time current sequence respectively to obtain discrete-frequency voltage sequences and discrete-frequency current sequences, including: Based on Fourier transform, frequency domain transformation is performed on the discrete-time voltage sequence and the discrete-time current sequence to obtain the discrete-frequency voltage sequence and the discrete-frequency current sequence. Fourier transform includes discrete Fourier transform or fast Fourier transform.

[0010] Furthermore, this wiring phase sequence identification method also includes: If the fundamental voltage collected by the reactive power compensation controller is a three-phase fundamental voltage and the fundamental current collected is a three-phase fundamental current, then the phase difference between each phase fundamental current and the three-phase fundamental voltage is calculated to obtain the three phase differences corresponding to each phase fundamental current; wherein, each phase fundamental current corresponds to a current channel. Obtain the voltage phase corresponding to the phase difference closest to the preset reference angle among the three phase differences corresponding to the fundamental current of each phase; The current transformer corresponding to each current channel is installed on the wiring of the corresponding voltage phase.

[0011] Furthermore, the preset reference angle is 90°.

[0012] Secondly, embodiments of this application provide a current transformer wiring phase sequence identification device, comprising: The data acquisition module is used to acquire the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller when the capacitor is connected in the main circuit of the power distribution device. The phase sequence identification module is used to obtain the absolute value of the difference between the phase difference and the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, the current transformer is determined to have an incorrect phase sequence. If the absolute value of the difference is less than the preset error threshold, the current transformer is determined to have a correct phase sequence.

[0013] Thirdly, embodiments of this application provide a wiring phase sequence identification device for a current transformer. The wiring phase sequence identification device includes a processor and a memory. The memory stores a computer program, which is loaded and executed by the processor to implement the wiring phase sequence identification method for a current transformer provided in the first aspect of embodiments of this application.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it is used to implement a current transformer wiring phase sequence identification method provided in the first aspect of embodiments of this application.

[0015] The wiring phase sequence identification method provided in this application has the following advantages compared with the prior art: In this embodiment, the phase difference between the fundamental voltage and fundamental current is collected after the capacitor is connected to the main circuit. The absolute value of the phase difference is then compared with a preset reference angle, and the absolute value is used to determine the correctness of the phase sequence of the current transformer wiring, in conjunction with a preset error threshold. By utilizing the capacitive current with fixed phase characteristics generated after the capacitor is connected, the problem of multiple solutions caused by the unknown load power factor angle when relying on random load current identification on site is completely avoided. In principle, the ambiguity of phase sequence identification is eliminated, ensuring that the identification result is unique and accurate, and is not constrained by the weight of the load on site, whether the load is inductive or capacitive, etc.

[0016] The embodiments of this application also rely on the quantitative comparison of phase difference with preset reference angle and the judgment method of error threshold, which can adapt to field interference such as power grid harmonics and small sampling deviations, and can flexibly adjust the fault tolerance range to further reduce the probability of misjudgment. Attached Figure Description

[0017] Figure 1 A flowchart illustrating the overall identification method according to an embodiment of this application is shown; Figure 2 A flowchart illustrating the phase sequence identification method for a current transformer according to an embodiment of this application is shown. Figure 3 A schematic flowchart of a method for obtaining phase difference according to an embodiment of this application is shown; Figure 4 A structural block diagram of a power distribution device according to an embodiment of this application is shown; Figure 5 A structural block diagram of the wiring phase sequence identification device according to an embodiment of this application is shown; Figure 6 A structural block diagram of a computer device according to an embodiment of this application is shown.

[0018] Explanation of reference numerals in the attached diagram: 401, Current transformer; 402, Reactive power compensation controller; 403, Switch; 404, Capacitor; 405, Power distribution device; 406, Main wiring circuit. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0020] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] Please refer to Figure 4 The wiring phase sequence identification method of this application embodiment is applied to a power distribution device 405, which includes: The reactive power compensation controller 402 integrates a microcontroller unit (MCU) main control chip, a synchronous analog-to-digital converter (ADC) sampling circuit, a digital signal processing unit, a parameter storage module, and a safety interlocking logic module. It features a 6.4kHz fixed synchronous sampling capability and supports frequency domain operations using Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT). It can perform functions such as voltage and current time-domain sequence storage, fundamental phase angle calculation, phase difference determination, and phase sequence determination. A built-in safety interlocking program automatically switches the shielding capacitor when phase sequence identification is initiated, preventing conflicts between the testing process and normal compensation logic.

[0023] The current transformer 401 is directly mounted on the incoming and outgoing busbars inside the power distribution device 405. It is divided into two types: a common-compensation single current transformer configuration and a separate-compensation three-phase current transformer configuration. The secondary signal line of the current transformer 401 is connected to each current channel of the reactive power compensation controller 402. It is responsible for collecting the primary load current of each phase and the capacitive test current generated by capacitor switching, and converting the large current into a weak current analog current signal that can be collected by the reactive power compensation controller 402.

[0024] Capacitor 404 is integrated into the main circuit 406 of the power distribution device 405 and is paired with switch 403. The switch 403 can be manually or automatically closed to connect capacitor 404 to the main circuit 406, generating capacitive current with fixed phase characteristics (90° leading voltage), thus eliminating the ambiguity in the determination caused by the variable load power factor angle in the traditional solution.

[0025] The Human Machine Interface (HMI) module communicates and interacts with the reactive power compensation controller 402. In this embodiment, the HMI module has three functions: first, receiving operator instructions and activating the phase sequence identification function; second, outputting standardized operation guidance text during the test process to prompt the user to connect the capacitor 404; and third, visually displaying the mapping relationship between the current transformer 401 and the voltage phase after identification, and outputting wiring error correction prompts (such as incorrect phase installation of the current transformer 401).

[0026] The main wiring circuit 406 includes three-phase buses A, B, and C, a neutral line, and voltage sampling terminals, providing three-phase voltage analog signals to the reactive power compensation controller 402. In this embodiment, it is divided into two wiring forms: common-phase voltage sampling and separate-phase voltage sampling. The reactive power compensation controller 402 synchronously collects the bus voltage as a voltage reference for phase difference calculation.

[0027] The 405 power distribution device is compatible with both three-phase common compensation and three-phase separate compensation topologies. It can match two-phase sampling voltage with a single current transformer, and also supports one-to-one correspondence between three-phase current transformers and three-phase voltage. It can be widely used in power systems with low-voltage inductive loads, such as urban power grids, rural power grids, civil buildings, shopping malls and supermarkets, for low-voltage power distribution network reactive power compensation.

[0028] For details, please refer to Figure 1 This is the overall identification method according to an embodiment of the present application. The method relies on the coordinated operation of various hardware modules of the power distribution device 405 and includes the following steps: Step 101: The human-computer interaction module triggers recognition.

[0029] The operator selects the phase sequence identification function on the HMI module interface of the power distribution device 405 and sends the command to the reactive power compensation controller 402 MCU. The reactive power compensation controller 402 immediately activates the built-in safety interlocking logic to lock the automatic switching function of capacitor 404, so as to avoid random switching of capacitors during the test phase from interfering with the sampling signal and complete the system operation mode switch.

[0030] Step 102: Capacitor 404 generates a deterministic test current.

[0031] The HMI module interface pops up operation prompts to guide the operator to manually close the switching switch 403, putting the capacitor 404 of the main circuit 406 of the power distribution device 405 into operation; the capacitor generates a fixed-phase capacitive current, which flows through the current transformer 401 mounted on the busbar. The current transformer 401 transmits this standard current signal to the reactive power compensation controller 402 ADC sampling circuit to construct a test condition without variable interference, thus solving the original system's defect of relying on random load current for identification.

[0032] Step 103: The sampling circuit of the reactive power compensation controller 402 completes the synchronous acquisition of voltage and current.

[0033] In this embodiment, the reactive power compensation controller 402 synchronously acquires the analog voltage signal of the three-phase bus voltage and the analog current signal output by each current transformer 401 at a sampling frequency of 6.4kHz. The controller generates discrete digital signals through analog-to-digital conversion by ADC. The MCU buffers the signals according to the timing sequence to form a discrete time-domain sequence of voltage and current, thus completing the acquisition of the original electrical parameters.

[0034] Step 104: The reactive power compensation controller 402 digital processing unit completes the signal processing.

[0035] The MCU calls the DFT / FFT algorithm to perform frequency domain transformation on the time domain sequence, filter out grid harmonic interference, and extract the complex component of the 50Hz power frequency fundamental wave. Based on the real and imaginary parts of the complex components, the fundamental voltage phase angle and the fundamental current phase angle are calculated. The voltage and current phase difference is solved by calculating the difference between the fundamental voltage phase angle and the fundamental current phase angle. If it is a common line voltage sampling, the substitution calculation logic in the reactive power compensation controller 402 converts the line voltage phase into the phase voltage reference phase and then recalculates the effective phase difference.

[0036] Step 105: Perform a traversal matching and determination for multi-channel CT.

[0037] If a three-phase current transformer split-compensation topology is configured, the reactive power compensation controller 402 will cyclically calculate the phase difference between the current of each current transformer 401 and the three-phase voltages A / B / C respectively; if a single current transformer common-compensation topology is configured, only the single current and the three-phase voltage will be matched; the phase difference of each current that is closest to the 90° reference angle will be selected, and the bus phase corresponding to the current current transformer 401 will be locked.

[0038] Step 106: Complete wiring diagnosis, result display, and parameter update.

[0039] The reactive power compensation controller 402 compares the absolute value of the phase difference with the 90° reference and the preset error threshold to determine the correctness of the phase sequence of the current transformer 401 wiring; it intelligently diagnoses phase misalignment problems by combining the common compensation / separate compensation topology rules, and outputs a visual wiring mapping diagram and rectification suggestions through the HMI; at the same time, it automatically updates the reactive power compensation calculation parameters inside the reactive power compensation controller 402 according to the identified phase sequence of the current transformer 401; after the entire process is completed, the interlock is released and the normal reactive power compensation operation of the power distribution device 405 is restored.

[0040] The overall identification method of this application fully reuses the original reactive power compensation controller 402, current transformer 401, capacitor and sampling circuit of the power distribution device 405, without the need for additional hardware. It is completely compatible with the original hardware architecture, control logic and two compensation topologies, and realizes automatic self-testing of the wiring of the current transformer 401.

[0041] Please refer to Figure 2 This application provides a method for identifying the phase sequence of a current transformer 401, applied to a power distribution device 405. The power distribution device 405 is equipped with a reactive power compensation controller 402 and a current transformer 401. The phase sequence identification method includes the following steps: Step 201: With capacitor 404 connected in the main circuit 406 of the power distribution device 405, obtain the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller 402.

[0042] In this embodiment of the application, step 201 is generally limited to the premise that the main circuit 406 of the power distribution device 405 is connected to the capacitor 404. Under this premise, the entire chain operation from the acquisition, storage, frequency domain transformation, fundamental wave extraction to the final solution of the phase difference between the fundamental wave voltage and the fundamental wave current is fully executed.

[0043] After the 404 capacitor is put into operation, it will generate a stable capacitive current with a fixed phase characteristic. Under ideal conditions, the capacitor current leads the corresponding phase voltage by 90°, and the corresponding phase difference is fixed at -90°. Traditional solutions rely on random load current detection on site, and the load power factor angle changes randomly in real time. The phase difference has multiple solutions and confusion problems. However, after the capacitor is put into operation, the variable unknown is fixed to a certain value, eliminating the ambiguity of the judgment from the root.

[0044] When the phase sequence identification function is activated, the reactive power compensation controller 402 synchronously triggers the safety interlock logic, temporarily shutting down the automatic capacitor switching program. Only one set of capacitors is allowed to be switched on at a time as a dedicated test signal source, avoiding interference from automatic switching of the equipment to sample the data. This ensures that the collected current signal is only the standard capacitive current of the capacitor, without any load current superposition interference.

[0045] The capacitive current generated by the capacitor flows through the current transformer 401 installed on the corresponding phase busbar inside the power distribution device 405. The current transformer 401 converts the large primary current into a weak analog current signal and sends it to the sampling port of the reactive power compensation controller 402. At the same time, the three-phase busbar of the power distribution device 405 continuously outputs a stable three-phase voltage analog signal, providing two basic analog signals for synchronous sampling.

[0046] For details, please refer to Figure 3 The present application provides a method for obtaining phase difference, which includes the following steps: Step 301: Obtain the voltage discrete time domain sequence and the current discrete time domain sequence of the reactive power compensation controller 402.

[0047] In this embodiment, the instantaneous voltage and instantaneous current values ​​of the reactive power compensation controller 402 are synchronously sampled and converted from analog to digital at a preset sampling frequency to obtain discrete voltage digital signals and discrete current digital signals.

[0048] Specifically, the reactive power compensation controller 402 integrates a synchronous ADC sampling circuit, which works in conjunction with the MCU main control unit; the preset sampling frequency can be selected as 6.4kHz, which is suitable for the high-precision acquisition requirements of 50Hz power grid signals.

[0049] Instantaneous voltage and current values ​​are acquired synchronously without any time sampling offset. If there is a timing difference in voltage and current sampling, it will directly introduce additional phase offset error, resulting in distortion of the final phase difference calculation. The synchronous sampling design ensures that the timing of the voltage and current waveforms corresponds one-to-one.

[0050] The outputs of the bus voltage and current transformers 401 of the power distribution device 405 are continuously changing analog electrical signals, which the MCU cannot directly recognize. The ADC circuit quantizes the instantaneous values ​​of the continuous analog voltage and the instantaneous values ​​of the analog current at a fixed sampling interval, and converts them into discrete digital signals that can be stored and processed by the reactive power compensation controller 402, and outputs discrete voltage digital signals and discrete current digital signals respectively.

[0051] This application embodiment ensures consistent sampling accuracy across all channels by synchronously acquiring data at a unified fixed sampling frequency, adapting to the parallel acquisition requirements of multiple current channels under both three-phase common compensation and three-phase separate compensation topologies.

[0052] Furthermore, in this embodiment of the application, discrete voltage digital signals and discrete current digital signals are stored according to the sampling timing to obtain discrete time-domain voltage sequences and discrete time-domain current sequences.

[0053] Specifically, the MCU caches the discrete voltage digital signal and discrete current digital signal obtained from each sampling into the internal storage unit of the reactive power compensation controller 402 according to the sampling order, strictly following the sampling timing and not disrupting the data order.

[0054] A set of voltage digital signals arranged sequentially in time constitutes a voltage discrete time-domain sequence, and a set of current digital signals constitutes a current discrete time-domain sequence. The sequence completely records the discrete waveform data of voltage and current changing with time within a period, and completely preserves the time-domain characteristics of the original waveform.

[0055] This application embodiment provides complete original data for subsequent frequency domain transformation by fully storing the original time-domain waveform, avoiding spectrum leakage and fundamental wave extraction distortion caused by segmented waveform extraction, and improving the accuracy of phase calculation.

[0056] Step 302: Perform frequency domain transformation on the voltage discrete time domain sequence and the current discrete time domain sequence respectively to obtain the voltage discrete frequency domain sequence and the current discrete frequency domain sequence.

[0057] This application employs either Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT). Both algorithms can convert time-domain waveforms to frequency-domain spectra. FFT offers faster computation speed, making it suitable for the low-computing-power real-time computation scenarios of the 402 MCU reactive power compensation controller. Frequency domain conversion is performed independently on the discrete-time voltage sequence and the discrete-time current sequence, without interference, outputting discrete-frequency voltage sequences and discrete-frequency current sequences respectively.

[0058] Since the power grid commonly has 3rd, 5th, and 7th harmonic distortion, if the phase is directly calculated by the zero-crossing point of the waveform, the harmonics will significantly reduce the phase measurement accuracy. Therefore, the embodiments of this application separate different frequency components by frequency domain conversion, thereby separating the harmonics from the power frequency components and eliminating harmonic interference from the data level.

[0059] Step 303: Extract the power frequency components corresponding to the discrete frequency domain sequence of voltage and the discrete frequency domain sequence of current respectively to obtain the complex components of the fundamental voltage and the complex components of the fundamental current.

[0060] In this embodiment of the application, the power frequency of the low-voltage power distribution system is 50Hz. The spectral coordinates corresponding to 50Hz are located in the frequency domain sequence, the spectral data corresponding to this frequency are extracted separately, and the other harmonic frequency components are discarded.

[0061] The Fourier transform output is in complex form. The real part of the complex number represents the in-phase component of the signal, and the imaginary part represents the quadrature component. The complex number contains two key pieces of information: the amplitude and initial phase of the power frequency signal. After filtering, only the complex number corresponding to the 50Hz power frequency is retained, which are the complex components of the fundamental voltage and the fundamental current.

[0062] In this embodiment, after removing harmonic interference, only pure power frequency fundamental wave data is retained. Subsequent phase calculations are based solely on the fundamental wave component, which significantly improves the accuracy of phase difference calculations and avoids misjudgment of phase sequence caused by power grid distortion.

[0063] Step 304: Obtain the phase angle of the fundamental voltage and the phase angle of the fundamental current based on the complex components of the fundamental voltage and the fundamental current, respectively.

[0064] This application uses the arctangent function to solve for the phase angle, as shown in the following formula: Fundamental voltage phase angle:

[0065] Fundamental current phase angle:

[0066] in, For the imaginary part of a complex number, For the real part of the complex number, For the complex components of the fundamental voltage, It represents the complex component of the fundamental current.

[0067] In this embodiment, the initial phase angles of the voltage waveform fundamental frequency and the current waveform fundamental frequency are obtained by using the arctangent function. The two phase angles are unified with the same timing reference and have the conditions for direct difference calculation.

[0068] Step 305: Obtain the phase difference between the fundamental voltage and the fundamental current based on the fundamental voltage phase angle and the fundamental current phase angle.

[0069] The phase difference calculation formula of this application embodiment is as follows:

[0070] in, This represents the phase difference between the fundamental voltage and the fundamental current. This indicates that the fundamental current lags behind the fundamental voltage, corresponding to inductive loads such as motors; if This indicates that the fundamental current leads the fundamental voltage, corresponding to a 404 capacitive load.

[0071] This step ultimately outputs the pure, harmonic-free fundamental phase difference value between a single current channel and its corresponding voltage, thus completing all objectives of step 201.

[0072] Step 202: Obtain the absolute value of the phase difference and the absolute value of the difference between the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, it is determined that the wiring phase sequence of the current transformer 401 is incorrect; if the absolute value of the difference is less than the preset error threshold, it is determined that the wiring phase sequence of the current transformer 401 is correct.

[0073] Step 202 completes the quantization judgment based on the phase difference between the fundamental voltage and fundamental current output in step 201, realizing the determination of the wiring phase sequence of the current transformer 401. This step adopts a standardized numerical comparison mechanism, relying on the phase difference, preset reference angle, and preset error threshold to complete the binary judgment. It is compatible with two mainstream wiring topologies: mixed / common phase voltage sampling and common line voltage sampling. Both topologies reuse the judgment logic of this step, with only the pre-phase conversion process differing.

[0074] Specifically, the phase difference is calculated and output in step 201. This represents the angle by which the fundamental voltage leads the fundamental current; after capacitor 404 is connected, it generates capacitive current, which ideally leads the voltage by 90°. The preset reference angle is fixed at 90° in this embodiment to match the inherent phase characteristics of the capacitor current.

[0075] In this embodiment, the matching judgment is completed by calculating the absolute value of the measured phase difference and the absolute value of the difference between the preset reference angle. Since the capacitive current generated after the capacitor 404 is put into operation ideally leads the corresponding phase voltage by 90°, the phase difference calculated in this embodiment is approximately -90°. Therefore, it is equivalent to comparing the absolute value of the measured phase difference with the preset reference angle of 90°. The core purpose is to determine whether the capacitor current and the corresponding phase voltage meet the 90° standard phase offset relationship.

[0076] The preset error threshold in this application embodiment can be customized according to the sampling accuracy of the reactive power compensation controller 402 and the degree of harmonic distortion of the power grid. The conventional engineering value is 1°, and the allowed recognition range is 89°~91°, which is used to cover the small measurement deviation caused by sampling and calculation. It can also be customized to preset error thresholds such as 0.5° and 2°, with corresponding recognition ranges of 89.5°~90.5° and 88°~92°, respectively.

[0077] This application embodiment first calculates the absolute value of the difference between the measured phase difference and the preset reference angle, and then compares the calculated absolute value with a preset error threshold, determining two possible results: If the absolute value of the difference is greater than or equal to the preset error threshold, the current transformer 401 is determined to have an incorrect phase sequence. If the absolute value of the difference is less than the preset error threshold, the wiring phase sequence of the current transformer 401 is determined to be correct.

[0078] Traditional solutions rely on random load current and random changes in the load power factor angle, and the same phase difference can correspond to two types of wiring: correct and incorrect. This step generates a fixed phase signal based on actively energized capacitors, which has only one matching solution and the comparison results are unambiguous.

[0079] This application does not use a rigid determination that is strictly equal to 90°. Instead, it introduces an error threshold to encompass power grid harmonics, ADC sampling noise, and Fourier transform calculation errors, thereby avoiding misjudgments caused by slight signal distortions on site.

[0080] Regardless of whether the mixed / common compensation mode of phase voltage sampling or the common compensation mode of line voltage sampling is used, after the corresponding phase conversion is completed in step 201, the absolute value comparison logic of this application embodiment is used to complete the determination. There is no need to modify the judgment algorithm, which has strong versatility.

[0081] The determination result of this application embodiment can be directly transmitted to the human-machine interface of the reactive power compensation controller 402, and automatically output fault prompts such as incorrect phase connection of current transformer 401, incorrect connection of same phase, and reversed phase sequence of current transformer 401, while automatically correcting the internal operating parameters of reactive power compensation.

[0082] Specifically, in mixed compensation or common compensation (phase voltage) synchronous sampling scenarios, the reactive power compensation controller 402 directly and synchronously collects the phase voltages of phases A, B, and C. , , Current transformers 401 are respectively installed on the busbars of phases A, B, and C, and the current path... , , Each phase current transformer 401 has a one-to-one correspondence with its secondary output. Voltage and current sampling are based on the same phase, so no phase conversion is required.

[0083] The reactive power compensation controller 402 synchronously samples the instantaneous values ​​of the three-phase phase voltages and the instantaneous values ​​of the currents in each channel at 6.4kHz, converts them from analog to digital, and stores them to obtain discrete time-domain sequences of voltage and current. It then performs FFT / DFT frequency-domain conversion on the time-domain sequences to extract the complex components of the 50Hz power frequency fundamental wave, and calculates the phase angle of each phase voltage. , , Phase angle of each current channel , , ; Calculate the phase difference between the single-channel current and the three-phase voltages of phases A, B, and C for each channel, so as to For example, a channel: ; ; .

[0084] Each current channel can obtain three independent phase difference data.

[0085] Calculate the phase difference for all three phases of a single current channel. ; Select the smallest absolute value among the three sets of values. The phase voltage corresponding to this value is the currently physically installed phase of current transformer 401; Compare the selected smallest absolute value with the preset error threshold and execute the judgment rule in step 202: The minimum absolute value is less than the preset error threshold: the current transformer 401 is installed in phase with the matching voltage and the wiring phase sequence is correct; The minimum absolute value is greater than the preset error threshold: No phase voltage meets the 90° phase match, the current transformer 401 is misconnected or the phase is installed incorrectly.

[0086] In the scenario of simultaneous sampling of line voltage, the voltage terminals of the reactive power compensation controller 402 are only connected to two phase buses (taking phases B and C as an example to collect line voltage). The entire device is equipped with only a single current transformer. The specification requires that the current transformer 401 be installed on the unsampled A-phase busbar (different phase); if the current transformer 401 is installed on the B or C phases, it is considered an incorrect connection in the same phase. This topology cannot directly obtain the A-phase voltage reference, so it is necessary to perform mathematical conversion on the line voltage phase, calculate the phase difference, and then send it to step 202 to complete the judgment.

[0087] ADC synchronous acquisition line voltage Instantaneous value, current transformer 401 output current Instantaneous values ​​are converted and stored to obtain discrete time-domain sequences of voltage and current; after FFT transformation, the 50Hz power frequency fundamental component is extracted to obtain the line voltage. initial phase The initial phase of phase A current Line voltage There is a fixed 90° phase shift between phase A and the phase voltage of phase A. Derive the phase of the reference phase voltage of phase A: .

[0088] The phase difference is calculated using the converted A-phase reference voltage and the current from current transformer 401: .

[0089] This phase difference is the effective phase difference matching the A-phase reference, and the phase difference data in the equivalent phase voltage sampling mode.

[0090] Based on the effective phase difference obtained through conversion Calculate the absolute value of the difference and substitute it into the judgment logic of step 202 for comparison with the preset error threshold: If the absolute value of the difference is less than the preset error threshold: the measured phase difference is close to 90°, which proves that the current transformer 401 is installed in phase A (different phase), which conforms to the common compensation wiring specification, and the wiring phase sequence is determined to be correct. If the absolute value of the difference is greater than or equal to the preset error threshold: the measured phase difference is only close to 30° or 150°, which means that the current transformer 401 is installed in phase B or phase C (same phase), and the wiring phase sequence is determined to be incorrect. The reactive power compensation controller 402 prompts the construction personnel to move the current transformer 401 to the A phase busbar.

[0091] Regardless of whether the front end directly samples the phase voltage or converts the line voltage to the equivalent phase voltage, all topologies only add the corresponding phase conversion calculation in step 201, and finally output the effective phase difference in a unified format. The absolute value calculation of the difference, threshold comparison, and right / wrong judgment logic in step 202 are completely unchanged. One judgment algorithm is compatible with all mainstream reactive power compensation wiring schemes, which greatly reduces the difficulty of developing the reactive power compensation controller 402 program, while ensuring that the phase sequence identification standard of the current transformer 401 is unified and the judgment result is stable and reliable under the two topologies.

[0092] Please refer to Figure 5 A current transformer 401 wiring phase sequence identification device provided in this application embodiment includes: The data acquisition module 501 is used to acquire the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller 402 when the capacitor 404 is connected in the main circuit 406. The phase sequence identification module 502 is used to obtain the absolute value of the difference between the phase difference and the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, the phase sequence of the current transformer 401 is determined to be incorrect; if the absolute value of the difference is less than the preset error threshold, the phase sequence of the current transformer 401 is determined to be correct.

[0093] The wiring phase sequence identification device in this application embodiment can be a computer device or a component within the computer device, such as an integrated circuit or a chip. The computer device can be a terminal or other devices besides a terminal. For example, the computer device can be a mobile phone, tablet computer, laptop computer, PDA, in-vehicle computer device, mobile internet device (MID), ultra-mobile personal computer (UMPC), netbook, or personal digital assistant (PDA), etc., and can also be a server, network attached storage (NAS), personal computer (PC), etc. This application embodiment does not specifically limit the device.

[0094] The wiring phase sequence identification device provided in this application embodiment can achieve... Figure 2The various processes implemented in the embodiment of the wiring phase sequence identification method will not be described again here to avoid repetition.

[0095] This application also provides a computer device, please refer to... Figure 6 The computer device includes a processor 601 and a memory 602. The memory 602 stores a program or instruction that can be run on the processor 601. When the program or instruction is executed by the processor 601, it implements each step of the above-mentioned current transformer 401 wiring phase sequence identification method and can achieve the same technical effect. To avoid repetition, it will not be described in detail here.

[0096] It should be noted that the computer device in the embodiments of this application includes the mobile computer device and the non-mobile computer device described above.

[0097] The memory 602 can be used to store software programs and various data. The memory 602 may primarily include a first storage area for storing programs or instructions and a second storage area for storing data. The first storage area may store the operating system, application programs or instructions required for at least one function (such as sound playback, image playback, etc.). Furthermore, the memory 602 may include volatile memory or non-volatile memory, or both. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DRRAM). The memory 602 in this embodiment includes, but is not limited to, these and any other suitable types of memory.

[0098] Processor 601 may include one or more processing units; optionally, processor 601 integrates an application processor and a modem processor, wherein the application processor mainly handles operations involving the operating system, user interface, and applications, and the modem processor mainly handles wireless communication signals, such as a baseband processor. It is understood that the aforementioned modem processor may also not be integrated into processor 601.

[0099] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described current transformer 401 wiring phase sequence identification method embodiment and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0100] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run programs or instructions to implement the various processes of the above-described current transformer 401 wiring phase sequence identification method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0101] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0102] This application also provides a computer program product, which is stored in a storage medium and executed by at least one processor to implement the various processes of the current transformer 401 wiring phase sequence identification method embodiment described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0103] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0104] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for identifying the phase sequence of a current transformer, characterized in that, The wiring phase sequence identification method is applied to a power distribution device equipped with a reactive power compensation controller and a current transformer. The wiring phase sequence identification method includes: With the capacitor connected in the main circuit of the power distribution device, the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller is obtained. Obtain the absolute value of the difference between the absolute value of the phase difference and the absolute value of the difference between the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, it is determined that the wiring phase sequence of the current transformer is incorrect; if the absolute value of the difference is less than the preset error threshold, it is determined that the wiring phase sequence of the current transformer is correct. The preset reference angle is 90°.

2. The wiring phase sequence identification method according to claim 1, characterized in that, When a capacitor is connected in the main circuit, obtaining the phase difference between the fundamental voltage and the fundamental current collected by the reactive power compensation controller includes: Obtain the voltage discrete-time sequence and the current discrete-time sequence of the reactive power compensation controller; The voltage discrete time-domain sequence and the current discrete time-domain sequence are respectively transformed into frequency domain sequences to obtain voltage discrete frequency domain sequences and current discrete frequency domain sequences. The power frequency components corresponding to the discrete frequency domain sequence of voltage and the power frequency components corresponding to the discrete frequency domain sequence of current are extracted respectively to obtain the complex components of the fundamental voltage and the complex components of the fundamental current. The phase angles of the fundamental voltage and the fundamental current are obtained from the complex components of the fundamental voltage and the complex components of the fundamental current, respectively. The phase difference between the fundamental voltage and the fundamental current is obtained based on the phase angle of the fundamental voltage and the phase angle of the fundamental current.

3. The wiring phase sequence identification method according to claim 2, characterized in that, The step of obtaining the voltage discrete-time sequence and current discrete-time sequence of the reactive power compensation controller includes: The instantaneous voltage and instantaneous current values ​​of the reactive power compensation controller are synchronously sampled and converted from analog to digital at a preset sampling frequency to obtain discrete digital voltage signals and discrete digital current signals. The discrete voltage digital signal and the discrete current digital signal are stored according to the sampling timing to obtain the discrete time-domain sequence of voltage and the discrete time-domain sequence of current.

4. The wiring phase sequence identification method according to claim 2, characterized in that, The step of performing frequency domain transformation on the discrete-time voltage sequence and the discrete-time current sequence to obtain the discrete-frequency voltage sequence and the discrete-frequency current sequence includes: Based on Fourier transform, the voltage discrete time-domain sequence and the current discrete time-domain sequence are respectively transformed into the frequency domain to obtain the voltage discrete frequency domain sequence and the current discrete frequency domain sequence; The Fourier transform includes the Discrete Fourier Transform or the Fast Fourier Transform.

5. The wiring phase sequence identification method according to claim 1, characterized in that, The wiring phase sequence identification method further includes: If the fundamental voltage collected by the reactive power compensation controller is a three-phase fundamental voltage and the fundamental current collected is a three-phase fundamental current, then the phase difference between each phase fundamental current and the three-phase fundamental voltage is calculated to obtain the three phase differences corresponding to each phase fundamental current; wherein, each phase fundamental current corresponds to a current channel. Obtain the voltage phase corresponding to the phase difference that is closest to the preset reference angle among the three phase differences corresponding to the fundamental current of each phase; The current transformer corresponding to each current channel is installed on the wiring of the corresponding voltage phase.

6. A current transformer wiring phase sequence identification device, characterized in that, The wiring phase sequence identification device includes: The data acquisition module is used to acquire the phase difference between the fundamental voltage collected by the reactive power compensation controller and the fundamental current collected by the reactive power compensation controller when the capacitor is connected in the main circuit of the power distribution device. The phase sequence identification module is used to obtain the absolute value of the difference between the absolute value of the phase difference and the absolute value of the difference between the preset reference angle. If the absolute value of the difference is greater than or equal to the preset error threshold, the wiring phase sequence of the current transformer is determined to be incorrect; if the absolute value of the difference is less than the preset error threshold, the wiring phase sequence of the current transformer is determined to be correct; wherein, the preset reference angle is 90°.

7. A wiring phase sequence identification device for a current transformer, the wiring phase sequence identification device comprising a processor and a memory, wherein the memory stores a computer program, characterized in that, The computer program is loaded and executed by the processor to implement the wiring phase sequence identification method as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the wiring phase sequence identification method as described in any one of claims 1 to 5.

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