Online measurement method and device for ground capacitance current of power distribution network, and electronic equipment

Abstract

The invention provides an on-line measurement method for ground capacitance current of a power distribution network, and relates to the technical field of power system measurement, and the method comprises the steps: injecting a sine AC signal at an opening triangle of an electromagnetic voltage transformer of the power distribution network; the initial phase angle of the sine alternating current signal is zero; acquiring an acquired voltage response signal generated by the bus of the power distribution network during the period of injecting the sine alternating current signal; extracting a direct current bias voltage component from the voltage response signal; determining equivalent ground capacitance of the power distribution network based on the direct current bias voltage component; and determining the total capacitance current of the power distribution network under the rated voltage based on the equivalent ground capacitance. The method can achieve the purpose of online, safe, low-cost, high-precision and high-interference-resistance ground capacitance current measurement of the power distribution network.

Description

Technical Field

[0001] This invention relates to the field of power system measurement technology, specifically to an online measurement method, device, and electronic equipment for the ground capacitance current of a distribution network. Background Technology

[0002] The ground capacitance current of a distribution network is a key parameter affecting the safe and stable operation of the system, directly related to arc extinction during single-phase ground faults, overvoltage levels, and the settings of protection devices. Traditional methods for measuring ground capacitance have many drawbacks: 1. Offline measurement method: This method requires power outage operation, uses a dedicated capacitor bridge, is inefficient, and cannot reflect the real-time operating status of the power grid.

[0003] 2. Signal Injection Method: Injecting a different frequency AC signal (such as a signal higher than the power frequency) into the system and calculating the impedance by measuring the voltage and current vectors. This method requires an expensive signal source and a precise phase measurement unit, the system is complex, and it is susceptible to background harmonic interference.

[0004] 3. Fault recording method: This method uses transient signals when a single-phase ground fault occurs in the system for analysis. However, it is a passive measurement method, which is uncontrollable and has a limited chance of failure.

[0005] Therefore, there is an urgent need for a method for measuring the ground capacitance current of power distribution networks that can be performed online, safely, at low cost, with high accuracy and strong anti-interference capability. Summary of the Invention

[0006] In view of this, it is necessary to provide an online measurement method, device and electronic equipment for the ground capacitance current of the distribution network, so as to achieve the purpose of online, safe, low-cost, high-precision and anti-interference measurement of the ground capacitance current of the distribution network.

[0007] To address the above problems, this invention provides an online method for measuring the ground capacitance current of a power distribution network, comprising: A sinusoidal alternating current signal is injected into the open delta of the electromagnetic voltage transformer in the power distribution network; the initial phase angle of the sinusoidal alternating current signal is zero. During the injection of a sinusoidal alternating current signal, the voltage response signal generated by the distribution network bus is acquired. Extract the DC bias voltage component from the voltage response signal; Based on the DC bias voltage components, the equivalent capacitance to ground of the distribution network is determined; Based on the equivalent capacitance to ground, the total capacitive current of the distribution network under rated voltage is determined.

[0008] In one possible implementation, the frequency range of the sinusoidal alternating current signal is 5 Hz to 25 Hz.

[0009] In one possible implementation, the formula for calculating the equivalent capacitance to ground of the distribution network is:

[0010] in, The equivalent capacitance to ground of the distribution network. This is the DC bias voltage component. To apply the initial DC voltage of the distribution network before excitation, f The frequency of the sinusoidal alternating current signal. This represents the amplitude of the sinusoidal alternating current signal.

[0011] In one possible implementation, the formula for calculating the total capacitive current of the distribution network under rated voltage is:

[0012] in, This refers to the total capacitive current of the distribution network under rated voltage. For the power frequency of the distribution network, This refers to the system phase voltage of the distribution network.

[0013] In one possible implementation, the system frequency is 60Hz.

[0014] In one possible implementation, the frequency of the sinusoidal alternating current signal satisfies:

[0015] in, f The frequency of the sinusoidal alternating current signal. This represents the voltage amplitude generated by a sinusoidal alternating current signal in the open delta of an electromagnetic voltage transformer. This is the rated voltage of the electromagnetic voltage transformer. This is the rated frequency of the electromagnetic voltage transformer.

[0016] In one possible implementation, extracting the DC bias voltage component from the voltage response signal includes: The DC bias voltage component to be extracted is used as the system variable of the Kalman filter algorithm, and the voltage response signal is used as the control input of the Kalman filter algorithm to construct the state prediction equation. Based on the process noise covariance used to characterize the rate of change of the DC bias voltage component, and the state transition matrix, an error covariance prediction equation is constructed. Based on the error covariance prediction equation and the observation noise covariance, which characterizes the amplitude of the voltage response signal and is superimposed with the measurement noise, the Kalman gain is determined. During the update process of the Kalman filter algorithm, the measured DC bias voltage component is updated based on the state prediction equation and the Kalman gain until the final DC bias voltage component is obtained.

[0017] Secondly, the present invention also provides an online measurement device for the ground capacitance current of a power distribution network, comprising: An injection module is used to inject a sinusoidal alternating current signal into the open delta of an electromagnetic voltage transformer in a power distribution network; the initial phase angle of the sinusoidal alternating current signal is zero. The acquisition module is used to acquire the voltage response signal generated by the distribution network bus during the injection of a sinusoidal alternating current signal; An extraction module is used to extract the DC bias voltage component from the voltage response signal; The capacitance calculation module is used to determine the equivalent capacitance to ground of the distribution network based on the DC bias voltage component. The current calculation module is used to determine the total capacitive current of the distribution network under rated voltage based on the equivalent capacitance to ground.

[0018] Thirdly, the present invention also provides an electronic device, including a memory and a processor, wherein, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps of the online measurement method for the ground capacitance current of the distribution network as described in any of the preceding claims.

[0019] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the online measurement method for the distribution network-to-ground capacitance current as described in any of the preceding claims.

[0020] The beneficial effects of the above implementation are as follows: The online measurement method, device, and electronic equipment for the distribution network ground capacitance current provided by the present invention inject a sinusoidal alternating current signal at the open delta of the electromagnetic voltage transformer in the distribution network; during the injection of the sinusoidal alternating current signal, the voltage response signal generated by the distribution network bus is acquired; the DC bias voltage component is extracted from the voltage response signal; based on the DC bias voltage component, the equivalent ground capacitance of the distribution network is determined; and based on the equivalent ground capacitance, the total capacitance current of the distribution network under rated voltage is determined.

[0021] This invention does not require the use of a dedicated capacitor bridge, thus eliminating the need for power outages and enabling real-time monitoring under normal grid operation. By measuring the DC bias voltage component instead of the AC vector, it avoids complex phase measurements, resulting in lower costs. Signal injection via the transformer delta connection ensures safety. The method is insensitive to system parameter fluctuations and environmental interference, providing stable, reliable, and robust measurement results. Therefore, this invention achieves the goal of online, safe, low-cost, high-precision, and interference-resistant measurement of the distribution network's ground capacitance current. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A flowchart of an embodiment of the online measurement method for the ground capacitance current of a power distribution network provided by the present invention; Figure 2 A schematic block diagram of an embodiment of the online measurement device for the ground capacitance current of a power distribution network provided by the present invention; Figure 3 A schematic diagram of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0026] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0027] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0028] 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 the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] This invention provides an online measurement method, device, and electronic equipment for the ground capacitance current of a power distribution network, which will be described below.

[0030] This invention provides an online measurement method for the ground capacitance current of a power distribution network. This method can be implemented by executing an application program on an embedded microprocessor or DSP (Digital Signal Processing), such as... Figure 1 As shown, the method includes: S101. A sinusoidal alternating current signal is injected into the open delta of the electromagnetic voltage transformer in the distribution network; the initial phase angle of the sinusoidal alternating current signal is zero.

[0031] S102. During the injection of sinusoidal alternating current signal, acquire the voltage response signal generated by the distribution network bus.

[0032] Understandably, a high-precision ADC (Analog-to-Digital Converter) synchronously samples the bus voltage and transmits the data to the main control unit.

[0033] S103. Extract the DC bias voltage component from the voltage response signal.

[0034] It is understood that the extraction methods for the DC bias voltage component include the arithmetic mean method, the digital low-pass filter method, or the fast Fourier transform spectrum analysis method.

[0035] S104. Based on the DC bias voltage component, determine the equivalent capacitance to ground of the distribution network.

[0036] It is understandable that the equivalent capacitance to ground of the distribution network can be calculated based on the DC bias voltage component, the initial DC voltage of the system before excitation is applied, and the amplitude of the sinusoidal AC current signal.

[0037] S105. Based on the equivalent capacitance to ground, determine the total capacitive current of the distribution network under rated voltage.

[0038] It is understood that an AC current signal with a frequency of 5Hz to 25Hz and an initial phase of zero is injected into the distribution network; the DC bias voltage component in the voltage response of the distribution network to ground is measured; and the capacitance to ground and the power frequency capacitance current are calculated based on the amplitude and frequency of the injected current and the DC bias voltage component.

[0039] To address the shortcomings of existing technologies, this invention provides a method and apparatus for online measurement of distribution network ground capacitance and capacitive current that requires no power outages, does not rely on phase measurement, has strong anti-interference capabilities, high accuracy, and is easy to implement.

[0040] In some embodiments, the frequency range of the sinusoidal alternating current signal is 5 Hz to 25 Hz.

[0041] Understandably, the frequency of the sinusoidal alternating current signal can be 5Hz or 25Hz, or even 13Hz or 15Hz, with 13Hz being the preferred frequency. Using an extremely low frequency signal of 5-25Hz effectively avoids power frequency harmonic interference.

[0042] In some embodiments, the formula for calculating the equivalent capacitance to ground of a distribution network is:

[0043] in, The equivalent capacitance to ground of the distribution network. This is the DC bias voltage component. To apply the initial DC voltage of the distribution network before excitation, f The frequency of the sinusoidal alternating current signal. This represents the amplitude of the sinusoidal alternating current signal.

[0044] Understandably, by changing the amplitude of the injected current... or frequency Multiple measurements were performed, and the solution was obtained using fitting techniques. To eliminate random errors.

[0045] In some embodiments, the formula for calculating the total capacitive current of a distribution network under rated voltage is:

[0046] in, This refers to the total capacitive current of the distribution network under rated voltage. The system power frequency of the distribution network is 60Hz. This refers to the system phase voltage of the distribution network.

[0047] Understandably, directly outputting the capacitor current value that is of concern to maintenance personnel can guide applications such as arc suppression coil compensation.

[0048] In some embodiments, the frequency of the sinusoidal alternating current signal satisfies:

[0049] in, f The frequency of the sinusoidal alternating current signal. This represents the voltage amplitude generated by a sinusoidal alternating current signal in the open delta of an electromagnetic voltage transformer. This is the rated voltage of the electromagnetic voltage transformer. This is the rated frequency of the electromagnetic voltage transformer.

[0050] It is understood that the amplitude of the injected current signal is adaptively adjusted according to the rated parameters of the voltage transformer to meet the requirements. The relationship, among which The voltage amplitude generated by the injected signal in the open delta of the PT. and These are the rated voltage and rated frequency of the PT, respectively.

[0051] In some embodiments, extracting the DC bias voltage component from the voltage response signal includes: The DC bias voltage component to be extracted is used as the system variable of the Kalman filter algorithm, and the voltage response signal is used as the control input of the Kalman filter algorithm to construct the state prediction equation. Based on the process noise covariance used to characterize the rate of change of the DC bias voltage component, and the state transition matrix, an error covariance prediction equation is constructed. Based on the error covariance prediction equation and the observation noise covariance, which characterizes the amplitude of the voltage response signal and is superimposed with the measurement noise, the Kalman gain is determined. During the update process of the Kalman filter algorithm, the measured DC bias voltage component is updated based on the state prediction equation and the Kalman gain until the final DC bias voltage component is obtained.

[0052] Understandably, Kalman filtering is an optimal recursive data processing algorithm that estimates the state of a dynamic system using noisy observation data.

[0053] State-space model: uses state equations to describe the system dynamics and observation equations to describe the measurement process; Recursive processing: Only the state estimate from the previous time step and the current observation are needed; no historical data needs to be stored. Optimal estimation: The optimal estimate of the state is obtained under the meaning of minimizing the mean square error.

[0054] Algorithm mathematical model: 1. State equations (describing system evolution):

[0055] in: The system state at time k; : State transition matrix; : Control input; : Control input matrix; Process noise, ; 2. Observation equations (describing the measurement process):

[0056] in: : The observation value at time k; Observation matrix; Observation noise, ; Application model in DC voltage measurement: The problem of "measuring DC voltage in AC signals" can be modeled as follows: State definition: Assume the system state has only one variable: DC voltage value.

[0057] Equations of state: Assuming the DC voltage changes slowly:

[0058] Right now: ,

[0059] Observation equation: The measured value is DC voltage plus AC noise:

[0060] Right now: .

[0061] Kalman filtering consists of two main steps: prediction and update.

[0062] Step 1: Prediction (Time Update) 1.1 State Prediction:

[0063] 1.2 Error Covariance Prediction:

[0064] Step 2: Update (Measurement Update) 2.1 Kalman gain calculation:

[0065] 2.2 Status Update:

[0066] 2.3 Error Covariance Update:

[0067] Parameter Tuning Guide: 1. Process noise covariance Q Physical meaning: The rate of change of DC voltage; Setting principles: If the DC voltage is very stable: set a smaller Q (e.g., 1e-6); If the DC voltage changes slowly: set an appropriate Q (e.g., 1e-4); If the DC voltage changes rapidly: set a larger Q (e.g., 1e-2).

[0068] 2. Observation noise covariance R Physical meaning: Amplitude of AC signal + measurement noise; Setting principles: It is approximately equal to the square of the AC signal amplitude; If the AC signal amplitude is A, it is recommended that R≈A² / 2; It can be estimated by observing the variance of the original signal.

[0069] 3. Initial parameters P0 Initial uncertainty: A larger value can be set, and the filter will converge quickly; It is usually set as follows: ; Extension: Consider the case of slowly changing DC voltage; If the DC voltage itself is also changing slowly, the state model can be enhanced: Summary of advantages: In applications that measure DC voltage in AC signals, the core advantage of Kalman filtering is: Adaptive learning: Automatically adjusts the level of confidence in predicted and observed values; Optimal estimation: Provides the most accurate DC component estimate in a statistical sense; Real-time processing: The estimation result can be output immediately for each sampling point; Noise suppression: Effectively suppresses periodic AC interference and random noise; Fast convergence: It can quickly converge to the true value even when the initial value is inaccurate; By setting noise parameters appropriately, Kalman filtering can stably extract weak DC components from strong AC noise, and its performance is far superior to traditional filtering methods.

[0070] In some embodiments, upon power-up, the main control unit first controls the voltage sampling circuit to measure the initial DC voltage of the bus. .

[0071] Main control unit sets injection parameters: , (This amplitude is calculated to ensure that the PT is not saturated).

[0072] The programmable current source is activated to continuously inject a 13Hz sinusoidal current for several cycles into the system.

[0073] A high-precision ADC synchronously samples the bus voltage and transmits the data to the main control unit.

[0074] The signal processing module processes the sampled data: first, it performs digital band-stop filtering to strongly suppress the 50Hz power frequency and its harmonics; then, it calculates the arithmetic mean of the filtered signal to obtain... .

[0075] Will , , , Substitute into the formula to calculate .

[0076] Based on the system phase voltage and power frequency Calculate capacitor current .

[0077] Displays and stores the measured capacitance to ground value. and capacitor current value .

[0078] In some embodiments, the core of the online measurement method for the capacitance current to ground of a distribution network based on DC bias voltage provided by the present invention lies in: treating the distribution network system to ground as an equivalent capacitor to be measured. A frequency of is injected into it through a controlled current source. Amplitude A sinusoidal current signal with an initial phase of zero Measure the DC bias voltage generated by the system. Then, the capacitance to ground and the corresponding power frequency capacitor current can be calculated.

[0079] The specific steps are as follows: Signal injection: At the open delta of the electromagnetic voltage transformer in the distribution network, the injection frequency is... Amplitude The sinusoidal alternating current signal, in which The value range is from 5Hz to 25Hz.

[0080] Voltage response detection: Synchronous detection of the voltage response generated by the distribution network bus (relative to ground) during the injection signal period. .

[0081] DC component extraction: response signal to the detected voltage. Sampling is performed, and digital signal processing algorithms are used to accurately extract its DC bias voltage component. .

[0082] Capacitance calculation: Calculate the equivalent capacitance to ground of the distribution network using the following formula. :

[0083] in, The initial DC voltage of the system before applying excitation.

[0084] Capacitor current calculation: Based on the calculated total capacitance to ground Calculate the total capacitive current of the distribution network under rated voltage. :

[0085] in, The system frequency is 60Hz. Let be the phase voltage of the system.

[0086] Preferred solution: The frequency of the injected current signal is preferably 13Hz.

[0087] The amplitude of the injected current signal and frequency Adaptive adjustments are made based on the rated parameters of the voltage transformer to ensure compliance. To prevent magnetic saturation of the voltage transformer, the relationship between the two is as follows. The voltage amplitude generated by the injected signal in the open delta of the PT. and These are the rated voltage and rated frequency of the PT, respectively.

[0088] By changing the amplitude of the injected current or frequency Multiple measurements were performed, and the solution was obtained using fitting techniques. To eliminate random errors.

[0089] The device of the present invention includes: Main control unit: is an embedded microprocessor or DSP.

[0090] Low-frequency constant current source: Receives instructions from the main control unit and generates the required low-frequency sinusoidal current signal.

[0091] Coupling and isolation unit: safely injects current signals into the distribution network and achieves electrical isolation.

[0092] High-precision voltage sampling circuit: Includes anti-aliasing filter and high-resolution ADC for measuring bus voltage.

[0093] Signal processing module: Built into the main control unit, responsible for executing DC component extraction, capacitance and capacitance current calculation algorithms.

[0094] In summary, this invention discloses an online measurement method and device for the ground capacitance current of a distribution network based on DC bias voltage. This method injects a low-frequency sinusoidal current of 5-25Hz into the distribution network, detects the DC bias component in the system voltage response, and calculates the ground capacitance value using its definite mathematical relationship with the system's ground capacitance, further obtaining the power frequency capacitance current. This invention avoids complex vector calculations and phase measurements, features a simple system structure, low cost, strong anti-interference capability, and high accuracy, enabling truly safe online measurement and providing crucial data support for the safe operation and protection control of the distribution network.

[0095] The beneficial effects of this invention are: True online measurement: no power outages required, real-time monitoring is possible even when the power grid is operating normally.

[0096] High precision and high anti-interference capability: By measuring the DC component instead of the AC vector, complex phase measurements are avoided; and by using an extremely low frequency signal of 5-25Hz, power frequency harmonic interference is effectively avoided.

[0097] System simplification and low cost: The core is the accurate measurement of DC voltage, which is a mature technology with low cost and does not require expensive phase-locked loops or vector analysis modules.

[0098] High safety: PT saturation is fundamentally prevented through frequency selection and amplitude control.

[0099] The output parameters are intuitive and practical: they directly output the capacitor current value that is of concern to maintenance and operation, guiding applications such as arc suppression coil compensation.

[0100] High robustness: The method is not sensitive to fluctuations in system parameters and environmental interference, and the measurement results are stable and reliable.

[0101] like Figure 2 As shown, the present invention also provides an online measurement device 200 for the ground capacitance current of a power distribution network, comprising: The injection module 201 is used to inject a sinusoidal alternating current signal at the open delta of the electromagnetic voltage transformer in the power distribution network; the initial phase angle of the sinusoidal alternating current signal is zero. The acquisition module 202 is used to acquire the voltage response signal generated by the distribution network bus during the injection of a sinusoidal alternating current signal; Extraction module 203 is used to extract the DC bias voltage component from the voltage response signal; The capacitance calculation module 204 is used to determine the equivalent capacitance to ground of the distribution network based on the DC bias voltage component. The current calculation module 205 is used to determine the total capacitive current of the distribution network under rated voltage based on the equivalent capacitance to ground.

[0102] The online measurement device for the ground capacitance current of the distribution network provided in the above embodiments can realize the technical solution described in the above embodiments of the online measurement method for the ground capacitance current of the distribution network. The specific implementation principle of each module or unit can be found in the corresponding content in the above embodiments of the online measurement method for the ground capacitance current of the distribution network, and will not be repeated here.

[0103] like Figure 3 As shown, the present invention also provides an electronic device 300. The electronic device 300 includes a processor 301, a memory 302, and a display 303. Figure 3 Only some components of the electronic device 300 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0104] In some embodiments, memory 302 may be an internal storage unit of electronic device 300, such as a hard disk or memory of electronic device 300. In other embodiments, memory 302 may also be an external storage device of electronic device 300, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on electronic device 300.

[0105] Furthermore, the memory 302 may include both internal storage units of the electronic device 300 and external storage devices. The memory 302 is used to store application software and various types of data installed on the electronic device 300.

[0106] In some embodiments, processor 301 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 302 or process data, such as the online measurement method of distribution network capacitance current to ground in this invention.

[0107] In some embodiments, display 303 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 303 is used to display information from electronic device 300 and to display a visual user interface. Components 301-303 of electronic device 300 communicate with each other via a system bus.

[0108] In some embodiments of the present invention, when the processor 301 executes the online measurement program for the distribution network-to-ground capacitance current in the memory 302, the following steps can be implemented: A sinusoidal alternating current signal is injected into the open delta of the electromagnetic voltage transformer in the power distribution network; the initial phase angle of the sinusoidal alternating current signal is zero. During the injection of a sinusoidal alternating current signal, the voltage response signal generated by the distribution network bus is acquired. Extract the DC bias voltage component from the voltage response signal; Based on the DC bias voltage components, the equivalent capacitance to ground of the distribution network is determined; Based on the equivalent capacitance to ground, the total capacitive current of the distribution network under rated voltage is determined.

[0109] It should be understood that when the processor 301 executes the online measurement program for the distribution network capacitance current to ground in the memory 302, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0110] Furthermore, the embodiments of the present invention do not specifically limit the type of electronic device 300 mentioned. Electronic device 300 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, electronic device 300 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0111] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an online measurement method for the distribution network-to-ground capacitance current provided by the methods described above, the method comprising: A sinusoidal alternating current signal is injected into the open delta of the electromagnetic voltage transformer in the power distribution network; the initial phase angle of the sinusoidal alternating current signal is zero. During the injection of a sinusoidal alternating current signal, the voltage response signal generated by the distribution network bus is acquired. Extract the DC bias voltage component from the voltage response signal; Based on the DC bias voltage components, the equivalent capacitance to ground of the distribution network is determined; Based on the equivalent capacitance to ground, the total capacitive current of the distribution network under rated voltage is determined.

[0112] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0113] The online measurement method for the ground capacitance current of the distribution network provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An online measurement method for the ground capacitance current of a power distribution network, characterized in that, include: A sinusoidal alternating current signal is injected into the open delta of the electromagnetic voltage transformer in the distribution network. The initial phase angle of the sinusoidal alternating current signal is zero; During the injection of a sinusoidal alternating current signal, the voltage response signal generated by the distribution network bus is acquired. Extract the DC bias voltage component from the voltage response signal; Based on the DC bias voltage components, the equivalent capacitance to ground of the distribution network is determined; Based on the equivalent capacitance to ground, the total capacitive current of the distribution network under rated voltage is determined.

2. The online measurement method for the ground capacitance current of a distribution network according to claim 1, characterized in that, The frequency range of the sinusoidal alternating current signal is 5Hz to 25Hz.

3. The online measurement method for the ground capacitance current of a distribution network according to claim 1, characterized in that, The formula for calculating the equivalent capacitance to ground of a distribution network is: in, The equivalent capacitance to ground of the distribution network. This is the DC bias voltage component. To apply the initial DC voltage of the distribution network before excitation, f The frequency of the sinusoidal alternating current signal. This represents the amplitude of the sinusoidal alternating current signal.

4. The online measurement method for the ground capacitance current of a distribution network according to claim 3, characterized in that, The formula for calculating the total capacitive current of a distribution network under rated voltage is: in, This refers to the total capacitive current of the distribution network under rated voltage. For the power frequency of the distribution network, This refers to the system phase voltage of the distribution network.

5. The online measurement method for the ground capacitance current of a distribution network according to claim 4, characterized in that, The system operates at a power frequency of 60Hz.

6. The online measurement method for the ground capacitance current of a distribution network according to claim 1, characterized in that, The frequency of a sinusoidal alternating current signal satisfies: in, f The frequency of the sinusoidal alternating current signal. This represents the voltage amplitude generated by a sinusoidal alternating current signal in the open delta of an electromagnetic voltage transformer. This is the rated voltage of the electromagnetic voltage transformer. This is the rated frequency of the electromagnetic voltage transformer.

7. The online measurement method for the ground capacitance current of a distribution network according to any one of claims 1-6, characterized in that, Extracting the DC bias voltage component from the voltage response signal includes: The DC bias voltage component to be extracted is used as the system variable of the Kalman filter algorithm, and the voltage response signal is used as the control input of the Kalman filter algorithm to construct the state prediction equation. Based on the process noise covariance used to characterize the rate of change of the DC bias voltage component, and the state transition matrix, an error covariance prediction equation is constructed. Based on the error covariance prediction equation and the observation noise covariance, which characterizes the amplitude of the voltage response signal and is superimposed with the measurement noise, the Kalman gain is determined. During the update process of the Kalman filter algorithm, the measured DC bias voltage component is updated based on the state prediction equation and the Kalman gain until the final DC bias voltage component is obtained.

8. An online measurement device for the ground capacitance current of a power distribution network, characterized in that, include: The injection module is used to inject a sinusoidal alternating current signal into the open delta of the electromagnetic voltage transformer in the power distribution network. The initial phase angle of the sinusoidal alternating current signal is zero; The acquisition module is used to acquire the voltage response signal generated by the distribution network bus during the injection of a sinusoidal alternating current signal; An extraction module is used to extract the DC bias voltage component from the voltage response signal; The capacitance calculation module is used to determine the equivalent capacitance to ground of the distribution network based on the DC bias voltage component. The current calculation module is used to determine the total capacitive current of the distribution network under rated voltage based on the equivalent capacitance to ground.

9. An electronic device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps of the online measurement method for the ground capacitance current of the distribution network as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the online measurement method for the ground capacitance current of the distribution network as described in any one of claims 1 to 7.

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