Electric energy quality detection method and system for guaranteeing node characteristics of electric power system

Abstract

The invention discloses an electric energy quality detection method and system for guaranteeing node characteristics of an electric power system, and relates to the technical field of electric energy quality detection.The method comprises the steps that data synchronization alignment is conducted on electric power node data, and noise in the electric power node data subjected to data synchronization alignment is restrained; performing harmonic analysis and symmetric component decomposition on the target power node data, and tracking the frequency of a power system node; detecting the electric energy quality of the electric power system node, and analyzing the electric energy quality abnormal condition of the electric power system node; the method comprises the steps of obtaining abnormal key index data of an abnormal power system node, analyzing a root cause influencing the power quality of the power system node, obtaining target root cause data, and dispatching maintenance personnel to maintain the abnormal power system node based on the target root cause data, thereby realizing rapid and accurate power quality detection of the power system node. And meanwhile, the maintenance efficiency of the nodes of the power system is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power quality detection, and in particular to a power quality detection method and system for ensuring the node characteristics of a power system. Background Art

[0002] In a power system, the detection of the power quality of power system nodes is a core requirement for ensuring the safe and reliable operation of the system. Once there are problems with the power quality in power system nodes, it will not only cause losses during the operation of power equipment, but may also lead to problems with power equipment. Moreover, problems with the power quality of power system nodes will also spread through the power grid, triggering a chain reaction in the power grid and causing large-scale failures in the power grid. Therefore, it is particularly important to detect the power quality of power system nodes.

[0003] Currently, the conventional methods for detecting the power quality of power system nodes mainly include the following methods: 1. Based on Fourier transform, the signal is converted through fast Fourier transform and then the components of harmonics and interharmonics are analyzed. However, this method has high requirements for signal periodicity, requires a stable signal period, and has weak analysis capabilities for dynamic or transient changes in power system nodes; 2. The effective value detection method, by calculating the effective value of the voltage or current in the power system node to judge the situation of the voltage or current. However, this method requires calculations for multiple cycles and cannot quickly respond to the situation of power system nodes. Therefore, there is currently a lack of an effective method for detecting the power quality in power system nodes. Summary of the Invention

[0004] The purpose of the present invention is to provide a power quality detection method and system for ensuring the node characteristics of a power system to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A power quality detection method for ensuring the node characteristics of a power system, the method comprising: Step S100: Obtain the power node data of the power system node, perform data synchronization alignment on the power node data, and suppress the noise in the power node data after data synchronization alignment to obtain the target power node data; Step S200: Obtain the target power node data, perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system node to obtain the key index data of the power system node; Step S300: Obtain key index data, obtain the key index range data of the power system nodes, detect the power quality of the power system nodes, analyze the abnormal conditions of the power quality of the power system nodes, and obtain the abnormal key index data of the abnormal power system nodes; Step S400: Obtain the abnormal key index data of the abnormal power system nodes, analyze the root causes affecting the power quality of the power system nodes, obtain the target root cause data, and based on the target root cause data, dispatch maintenance personnel to repair the abnormal power system nodes.

[0006] Further, step S100 includes: Step S101: Obtain the power node data of the power system nodes, where the power node data includes the data corresponding to the three-phase voltage signals and three-phase current signals of the power system nodes in the current cycle; Step S102: Perform data synchronization and alignment on the power node data. Among them, the process of performing data synchronization and alignment on the data of the three-phase voltage signals in the power node data is as follows: Obtain the three-phase voltage signals from the power node data and denote them as phase A, phase B, and phase C respectively; Obtain the highest sampling frequency f from the power node data for the three-phase voltage signals respectively s ; Taking the sampling frequency f s as the reference, align the frequencies of the three-phase voltage signals to obtain the sampling interval T s = 1 / f s ; Obtain the phase A, phase B, and phase C in the three-phase voltage signals after sampling alignment as V a (t), V b (t), and V c (t); Obtain the sampling points of phase A, phase B, and phase C in the three-phase voltage signals and denote them as V a (n), V b (n), and V c (n), where n = 1, 2,..., N - 1, and N is the total number of sampling points of V a (t), and t = n·T s ; Step S103: Based on phase A, perform time delay compensation on phase B and phase C. The specific process is as follows: Estimate the time delay of phase C relative to phase A. The specific process is as follows: Obtain the cross-correlation sequence R (a,c) [d] of phase A and phase C; Based on the cross-correlation sequence R (a,c) [d], obtain the maximum value d max of d, and estimate the time delay τ of phase C relative to phase A(a,c) = d max · T s ; Estimate the time delay τ of phase B relative to phase A (a,b) ; Perform time delay compensation on phase C to obtain V´ c (n), and the specific formula is V´ c (n) = V c (n + τ (a,c) / T s ); Perform time delay compensation on phase B to obtain V´ b (n); Step S104: Respectively perform Fourier transforms on V a (n), V´ b (n), and V´ c (n) of the three-phase voltage signals to obtain V a [k], V´ b [k], and V´ c [k]; Respectively obtain the fundamental frequency indices k0 of V a [k], V´ b [k], and V´ c [k], and obtain the phases θ a , θ b , and θ c ; Obtain the phase difference △θ between phase A and phase B (a,b) = θ b - (θ a - 2π / 3), and obtain the phase difference △θ between phase A and phase C (a,c) = θ c - (θ a + 2π / 3); Respectively perform phase compensation on phase B and phase C to obtain V´ （△，b） (n) and V´ （△，c） (n), where performing phase compensation on phase B obtains V´ （△，b） [k], and performing inverse Fourier transform on V´ （△，b） [k] obtains V´ （△，b） (n); Step S105: Obtain the power node data after data synchronization and alignment, and suppress the power node data noise to obtain the target power node data; In the above steps, data synchronization and alignment of the power node data of the power system can ensure that the phase relationship between the three-phase voltage and the three-phase current in the power node data is not distorted and does not conceal the laws presented by the data, thereby making the results of subsequent processing of the power node data more accurate and facilitating subsequent detection of the power quality of the power system nodes.

[0007] Further, step S200 includes: Step S201: Obtain the target power node data, perform harmonic analysis on the target power node data to obtain the total harmonic distortion rates of the three-phase voltage signal and the three-phase current signal in the target power node data. Among them, the specific analysis process for the three-phase voltage signal in the target power node data is as follows: Perform Fourier transform on each phase signal in the three-phase voltage signal of the target power node data to obtain the frequency-domain complex numbers of the three-phase voltage signal; Extract harmonic parameters from the three-phase voltage signal to obtain the effective value V of phase A in the three-phase voltage signal a h , and the specific obtaining process is as follows: Obtain the frequency-domain complex number X (a,h) (k) of phase A, where f k =k·f s / N, N is the total number of sampling points of phase A, and f s is the highest sampling frequency in the three-phase voltage signal; Obtain the amplitude A of the hth harmonic of phase A h =(2·|X (a,h) (k)|) / N, obtain the effective value V of the hth harmonic of phase A a h =A h / 2 1 / 2 ; Obtain the harmonic distortion rate T of phase A in the three-phase voltage signal a v ; Obtain the harmonic distortion rates T of phase B and phase C in the three-phase voltage signal b v and the harmonic distortion rate T c v , and obtain the total harmonic distortion rate T of the three-phase voltage signal v =max{T a v ,T b v ,T c v}; Step S202: Perform symmetrical component decomposition on the three-phase voltage signal and three-phase current signal in the target power node data. Among them, the process of performing symmetrical component decomposition on the three-phase voltage signal is as follows: Obtain the effective values V b 1 and V c 1 of the fundamental wave voltages of phase B and phase C in the target power node data, and perform symmetrical component decomposition on the three-phase voltage signal in the target power node data to obtain the positive sequence voltage component V + 1 and the negative sequence voltage component V - 1 in the target power node data; Calculate the unbalance degree VUF of the three-phase voltage signal = (|V + 1| / |V - 1|) · 100%; Step S203: Track the frequency of the power system node. Among them, the process of tracking the frequency of the three-phase voltage signal in the power system node is as follows: Obtain the instantaneous values of phase A, phase B, and phase C in the three-phase voltage signal, convert the three-phase voltage signal into a stationary coordinate system, and extract the instantaneous phase angle θ v (t) of the three-phase voltage signal from the stationary coordinate system; Calculate the instantaneous frequency f v (t) of the three-phase voltage signal through the instantaneous phase angle θ v (t): , Obtain the fundamental wave frequency f0 in the power system node, and calculate the frequency deviation △f v (t) = f v (t) - f0; Step S204: Take the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signal and three-phase current signal in the target power node data as the key indicators of the power system node; Obtain the data of each key indicator in the three-phase voltage signal and three-phase current signal in the power system node and collect them to obtain the key indicator data of the power system node.

[0008] Furthermore, step S300 includes: Step S301: Obtain the key indicator data in the power system node, and obtain the data of each key indicator in the power system node from the key indicator data; Step S302: Obtain the key indicator range data of the power system node. The key indicator range data includes the preset ranges of each key indicator in the power system node; Detect the power quality of the power system node. The specific detection process is as follows: When the value of a certain key indicator is not within the range preset by the key indicator range data, mark the certain key indicator as an abnormal key indicator, and determine that there is abnormal power quality in the power system node during the current period. Step S303: When there are abnormal key indicators in the power system node, mark the power system node as an abnormal power system node, and obtain the data of each abnormal key indicator in the abnormal power system node to obtain abnormal key indicator data.

[0009] Furthermore, step S400 includes: Step S401: Obtain the abnormal key indicator data of the abnormal power system node, and obtain the root cause discrimination data of the abnormal power system node. The root cause discrimination data includes the preset ranges of each key indicator in each abnormal root cause. Step S402: Analyze the root cause affecting the power quality of the power system node to obtain quality impact root cause data. The specific analysis process is as follows: Obtain the data of each abnormal key indicator in the abnormal power system node from the abnormal key indicator data. When the maximum value and the minimum value of a certain abnormal key indicator in the abnormal power system node are within the preset range of a certain abnormal key indicator in a certain abnormal root cause, determine that a certain abnormal key indicator is an abnormal key indicator related to a certain abnormal root cause. Obtain the total number Q of abnormal key indicators related to a certain abnormal root cause in the abnormal key indicator data sum , obtain the total number Q sum The ratio to the total number of each abnormal key indicator in the abnormal key indicator data to obtain the probability value of a certain abnormal root cause in the abnormal power system node. Obtain the probability values of each abnormal root cause in the abnormal power system node. When the probability value of a certain abnormal root cause is greater than the preset probability threshold, mark the certain abnormal root cause as the target abnormal root cause, and obtain and collect several target abnormal root causes in the abnormal power system node to obtain target root cause data. Step S403: Obtain several target abnormal root causes in the target root cause data, and based on the maintenance equipment required for several target abnormal root causes, dispatch maintenance personnel in the area where the abnormal power system node is located to carry the maintenance equipment to repair the power system node.

[0010] In order to better implement the above method, a power quality detection system for ensuring the characteristics of power system nodes is also proposed. The system includes a data synchronization module, a key indicator acquisition module, a power quality detection module, and a node maintenance module; A data synchronization module, which is used to synchronize and align the power node data in the power system nodes, suppress the noise in the power node data after data synchronization and alignment, and obtain the target power node data; A key index acquisition module, which is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, track the frequency of the power system nodes, and obtain the key index data of the power system nodes; A power quality detection module, which is used to detect the power quality of the power system nodes, analyze the abnormal conditions of the power quality of the power system nodes, and obtain the abnormal key index data of the abnormal power system nodes; A node maintenance module, which is used to analyze the root causes affecting the power quality of the power system nodes to obtain the target root cause data, and dispatch maintenance personnel in the area where the abnormal power system nodes are located to repair the power system nodes according to the target root cause data.

[0011] Furthermore, the data synchronization module includes a data acquisition unit and a data synchronization unit; The data acquisition unit is used to acquire the power node data of the power system nodes. The power node data includes the data corresponding to the three-phase voltage signals and three-phase current signals of the power system nodes in the current cycle; The data synchronization unit is used to synchronize and align the power node data, suppress the noise in the power node data after data synchronization and alignment, and obtain the target power node data.

[0012] Furthermore, the key index acquisition module includes a data analysis unit and a key index acquisition unit; The data analysis unit is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, track the frequency of the power system nodes, and obtain the total harmonic distortion rate, unbalance degree, and frequency deviation data of the three-phase voltage signals and three-phase current signals of the power system nodes; The key index acquisition unit is used to use the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signals and three-phase current signals in the target power node data as the key indexes of the power system nodes, collect the data of each key index in the three-phase voltage signals and three-phase current signals in the power system nodes, and obtain the key index data of the power system nodes.

[0013] Furthermore, the power quality detection module includes a power quality detection unit; The power quality detection unit is used to acquire the key index data in the power system nodes, obtain the key index range data of the power system nodes, detect the power quality of the power system nodes, and obtain the abnormal key index data of the abnormal power system nodes.

[0014] Further, the node maintenance module includes a root cause analysis unit and a node maintenance unit; The root cause analysis unit is configured to obtain the abnormal key index data of the abnormal power system node, analyze the root cause affecting the power quality of the power system node, and obtain the target root cause data; The node maintenance unit is configured to dispatch maintenance personnel to repair the abnormal power system node according to the target root cause data.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention realizes the effective detection of the power quality of the power system nodes. When detecting the power quality of the power system nodes, the problem of data misalignment in the obtained power node data is considered. Therefore, the three-phase voltage and three-phase current in the power node data are aligned respectively to ensure the accuracy of subsequent analysis. Subsequently, by analyzing the power node data, the key indexes for judging the power quality are obtained, and with the specific data of the key indexes in the obtained power system nodes, the power quality of the power system nodes is detected and judged, so that the power quality of the power system nodes can be quickly and accurately detected. In addition, by analyzing the root cause affecting the power system nodes, the affected power system nodes can be quickly repaired, effectively ensuring the power quality of the power system nodes. Description of the Drawings

[0016] Figure 1 is a method flow chart of a power quality detection method for ensuring the characteristics of power system nodes according to the present invention; Figure 2 is a module schematic diagram of a power quality detection system for ensuring the characteristics of power system nodes according to the present invention. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Embodiment: As Figure 1 - Figure 2 shown, the present invention provides a technical solution, a power quality detection method for ensuring the characteristics of power system nodes, the method includes: Step S100: Obtain the power node data of the power system node, perform data synchronization alignment on the power node data, and suppress the noise in the power node data after data synchronization alignment to obtain the target power node data; Among them, step S100 includes: Step S101: Obtain the power node data of the power system nodes. The power node data includes the data corresponding to the three-phase voltage signals and three-phase current signals of the power system nodes in the current period; Step S102: Synchronize and align the power node data. Among them, the process of synchronizing and aligning the data of the three-phase voltage signals in the power node data is as follows: Obtain the three-phase voltage signals from the power node data and denote them as Phase A, Phase B, and Phase C respectively; Obtain the highest sampling frequency f from the three-phase voltage signals in the power node data respectively s ; Taking the sampling frequency f s as the reference, align the frequencies of the three-phase voltage signals to obtain the sampling interval T s = 1 / f s ; Obtain the Phase A, Phase B, and Phase C in the three-phase voltage signals after sampling alignment as V a (t), V b (t), and V c (t); Obtain the sampling points of Phase A, Phase B, and Phase C in the three-phase voltage signals and denote them as V a (n), V b (n), and V c (n), where n = 1, 2,..., N - 1, and N is the total number of sampling points of V a (t), and t = n·T s ; Step S103: Based on Phase A, perform time delay compensation on Phase B and Phase C. The specific process is as follows: Estimate the time delay of Phase C relative to Phase A. The specific process is as follows: Obtain the cross-correlation sequence R (a,c) [d] of Phase A and Phase C; For example, the specific formula for the cross-correlation sequence R (a,c) [d] is: , where d is the time offset, d ∈ [-T / 2, T / 2], and T is the preset fundamental wave period in the power system nodes; Based on the cross-correlation sequence R (a,c) [d], obtain the maximum value d max of d, and estimate the time delay τ (a,c) of Phase C relative to Phase A = d max ·T s ; For example, the specific formula for obtaining d max is: , Estimate the time delay τ of phase B relative to phase A (a,b) ; Perform time delay compensation on phase C to obtain V´ c (n), and the specific formula is V´ c (n)=V c (n + τ (a,c) / T s ); Perform time delay compensation on phase B to obtain V´ b (n); Step S104: Respectively perform Fourier transforms on V a (n), V´ b (n), and V´ c (n) of the three-phase voltage signals to obtain V a [k], V´ b [k], and V´ c [k]; Respectively obtain the fundamental frequency index k0 of V a [k], V´ b [k], and V´ c [k], and obtain the phases θ a , θ b , and θ c of phase A, phase B, and phase C; For example, the calculation formula for the phase θ a is: θ a = arg(V a [k0]); Obtain the phase difference △θ (a,b) between phase A and phase B = θ b - (θ a - 2π / 3), and obtain the phase difference △θ (a,c) between phase A and phase C = θ c - (θ a + 2π / 3); Respectively perform phase compensation on phase B and phase C to obtain V´ （△，b） (n) and V´ （△，c） (n), where performing phase compensation on phase B to obtain V´ （△，b） [k], and performing inverse Fourier transform on V´ （△，b） [k] to obtain V´ （△，b） (n); For example, the specific formula for V´ （△，b） [k] is: V´´ （△，b） [k]=V´ b [k]·e -j·△θ(a,c) ; Step S105: Obtain the power node data after data synchronization alignment, and suppress the noise of the power node data to obtain the target power node data; For example, the method for suppressing the noise of the power node data includes using adaptive wavelet threshold denoising; Step S200: Obtain the target power node data, perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system nodes to obtain the key index data of the power system nodes; Among them, Step S200 includes: Step S201: Obtain the target power node data, perform harmonic analysis on the target power node data to obtain the total harmonic distortion rates of the three-phase voltage signal and the three-phase current signal in the target power node data. Among them, the specific analysis process for the three-phase voltage signal in the target power node data is as follows: Perform Fourier transform on each phase signal in the three-phase voltage signal of the target power node data to obtain the frequency-domain complex numbers of the three-phase voltage signal; Extract harmonic parameters from the three-phase voltage signal to obtain the effective value V of phase A in the three-phase voltage signal a h The specific acquisition process is as follows: Obtain the frequency-domain complex number X (a,h) (k) of phase A, where f k =k·f s / N, N is the total number of sampling points of phase A, and f s is the highest sampling frequency in the three-phase voltage signal; Obtain the amplitude A of the hth harmonic of phase A h =(2·|X (a,h) (k)|) / N, obtain the effective value V of the hth harmonic of phase A a h =A h / 2 1 / 2 ; Obtain the harmonic distortion rate T of phase A in the three-phase voltage signal a v ; For example, calculate the harmonic distortion rate T of phase A a v The specific formula is: Among them, H is the preset highest harmonic order of the three-phase voltage signal in the power system node; V a 1 is the effective value of the fundamental wave voltage of phase A in the power system node; Obtain the harmonic distortion rates T of phase B and phase C in the three-phase voltage signal bv Total harmonic distortion rate T of harmonic c v , obtain the total harmonic distortion rate T of the three-phase voltage signal v = max{T a v , T b v , T c v}; Step S202: Perform symmetrical component decomposition on the three-phase voltage signal and three-phase current signal in the target power node data. Among them, the process of performing symmetrical component decomposition on the three-phase voltage signal is as follows: Obtain the effective values V b 1 and V c 1 of the fundamental wave voltages of phase B and phase C in the target power node data, and perform symmetrical component decomposition on the three-phase voltage signal in the target power node data to obtain the positive sequence voltage component V + 1 and the negative sequence voltage component V - 1 of the target power node data; For example, the specific formula for performing symmetrical component decomposition on the three-phase voltage signal in the target power node data is: , where a = e j120° ; V0 is the zero sequence voltage component; Calculate the unbalance degree VUF of the three-phase voltage signal = (|V + 1| / |V - 1|) · 100%; Step S203: Track the frequency of the power system node. Among them, the process of tracking the frequency of the three-phase voltage signal in the power system node is as follows: Obtain the instantaneous values of phase A, phase B, and phase C in the three-phase voltage signal, convert the three-phase voltage signal into a stationary coordinate system, and extract the instantaneous phase angle θ v (t) of the three-phase voltage signal from the stationary coordinate system; For example, the conversion formula for converting the three-phase voltage signal into a stationary coordinate system is: , where v a (t), v b (t), and v c (t) are the instantaneous values of phase A, phase B, and phase C; Extract the instantaneous phase angle θ v (t) of the three-phase voltage signal from the stationary coordinate system: , Through the instantaneous phase angle θ v(t) Calculate the instantaneous frequency f of the three-phase voltage signal v (t): , Obtain the fundamental frequency f0 in the power system node, and calculate the frequency deviation △f of the three-phase voltage signal in the power system node v f(t) = f v (t) - f0; Step S204: Use the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as the key indicators of the power system node; Obtain the data of each key indicator in the three-phase voltage signal and the three-phase current signal in the power system node and gather them to obtain the key indicator data of the power system node; Step S300: Obtain the key indicator data, obtain the key indicator range data of the power system node, detect the power quality of the power system node, and analyze the abnormal power quality condition of the power system node to obtain the abnormal key indicator data of the abnormal power system node; Among them, step S300 includes: Step S301: Obtain the key indicator data in the power system node, and obtain the data of each key indicator in the power system node from the key indicator data; Step S302: Obtain the key indicator range data of the power system node. The key indicator range data includes the preset ranges of each key indicator in the power system node; Detect the power quality of the power system node. The specific detection process is as follows: When the value of a certain key indicator is not within the preset range of the key indicator range data, mark a certain key indicator as an abnormal key indicator, and determine that there is an abnormal power quality in the power system node in the current cycle; Step S303: When there are abnormal key indicators in the power system node, mark the power system node as an abnormal power system node, and obtain the data of each abnormal key indicator in the abnormal power system node to obtain the abnormal key indicator data; Step S400: Obtain the abnormal key indicator data of the abnormal power system node, analyze the root cause affecting the power quality of the power system node to obtain the target root cause data, and based on the target root cause data, dispatch maintenance personnel to repair the abnormal power system node; Among them, step S400 includes: Step S401: Obtain the abnormal key indicator data of the abnormal power system node, and obtain the root cause discrimination data of the abnormal power system node. The root cause discrimination data includes the preset ranges of each key indicator in each abnormal root cause; For example, the root causes of various anomalies include generator failures, cable insulator aging, etc.; Step S402: Analyze the root causes affecting the power quality of the power system nodes to obtain quality impact root cause data. The specific analysis process is as follows: Obtain the data of each abnormal key index in the abnormal power system node from the abnormal key index data. When the maximum value and the minimum value of a certain abnormal key index in the abnormal power system node are within the preset range of a certain abnormal key index in a certain abnormal root cause, determine that a certain abnormal key index is the relevant abnormal key index of a certain abnormal root cause; Obtain the total number Q of the relevant abnormal key indexes of a certain abnormal root cause in the abnormal key index data sum , obtain the total number Q sum Calculate the ratio between the total number Q and the total number of each abnormal key index in the abnormal key index data to obtain the probability value of a certain abnormal root cause in the abnormal power system node; Obtain the probability values of each abnormal root cause in the abnormal power system node. When the probability value of a certain abnormal root cause is greater than the preset probability threshold, record a certain abnormal root cause as the target abnormal root cause, obtain several target abnormal root causes in the abnormal power system node and gather them to obtain the target root cause data; Step S403: Obtain several target abnormal root causes in the target root cause data, and based on the maintenance equipment required for several target abnormal root causes, dispatch the maintenance personnel in the area where the abnormal power system node is located to carry the maintenance equipment to repair the power system node; For example, the maintenance equipment includes reverse power protection measurement and control devices, automatic transfer switches, UPS hosts, etc.; In order to better implement the above method, a power quality detection system for guaranteeing the characteristics of power system nodes is also proposed. The system includes a data synchronization module, a key index acquisition module, a power quality detection module, and a node maintenance module; The data synchronization module is used to synchronize and align the power node data in the power system node, and suppress the noise in the power node data after data synchronization and alignment to obtain the target power node data; The key index acquisition module is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system node to obtain the key index data of the power system node; The power quality detection module is used to detect the power quality of the power system node, and analyze the abnormal conditions of the power quality of the power system node to obtain the abnormal key index data of the abnormal power system node; A node maintenance module, which is used to analyze the root causes affecting the power quality of power system nodes, obtain target root cause data, and dispatch maintenance personnel in the area where the abnormal power system nodes are located to repair the power system nodes according to the target root cause data; Among them, the data synchronization module includes a data acquisition unit and a data synchronization unit; The data acquisition unit is used to acquire power node data of power system nodes. The power node data includes data corresponding to three-phase voltage signals and three-phase current signals of power system nodes in the current cycle; The data synchronization unit is used to synchronize and align the power node data, and suppress the noise of the power node data after data synchronization and alignment to obtain target power node data; Among them, the key index acquisition module includes a data analysis unit and a key index acquisition unit; The data analysis unit is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of power system nodes to obtain data on the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signals and three-phase current signals of power system nodes; The key index acquisition unit is used to use the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signals and three-phase current signals in the target power node data as the key indexes of power system nodes, collect the data of each key index in the three-phase voltage signals and three-phase current signals of power system nodes, and obtain the key index data of power system nodes; Among them, the power quality detection module includes a power quality detection unit; The power quality detection unit is used to acquire the key index data of power system nodes, obtain the key index range data of power system nodes, detect the power quality of power system nodes, and obtain the abnormal key index data of abnormal power system nodes; Among them, the node maintenance module includes a root cause analysis unit and a node maintenance unit; The root cause analysis unit is used to acquire the abnormal key index data of abnormal power system nodes, analyze the root causes affecting the power quality of power system nodes, and obtain target root cause data; The node maintenance unit is used to dispatch maintenance personnel to repair abnormal power system nodes according to the target root cause data.

[0019] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Accordingly, all changes that fall within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A power quality detection method for ensuring the node characteristics of a power system, characterized in that, The method includes: Step S100: Obtain the power node data of the power system nodes, perform data synchronization alignment on the power node data, and suppress the noise in the power node data after data synchronization alignment to obtain target power node data; Step S200: Obtain the target power node data, perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system nodes to obtain the key index data of the power system nodes; Step S300: Obtain the key index data, obtain the key index range data of the power system nodes, detect the power quality of the power system nodes, and analyze the abnormal conditions of the power quality of the power system nodes to obtain the abnormal key index data of the abnormal power system nodes; Step S400: Obtain the abnormal key index data of the abnormal power system nodes, analyze the root causes affecting the power quality of the power system nodes to obtain target root cause data, and based on the target root cause data, dispatch maintenance personnel to repair the abnormal power system nodes.

2. The power quality detection method for guaranteeing the node characteristics of a power system according to claim 1, characterized in that, The step S100 includes: Step S101: Obtain the power node data of the power system nodes, where the power node data includes the data corresponding to the three-phase voltage signals and three-phase current signals of the power system nodes in the current cycle; Step S102: Perform data synchronization alignment on the power node data. Among them, the process of performing data synchronization alignment on the data of the three-phase voltage signals in the power node data is: Obtain the three-phase voltage signals from the power node data and denote them as phase A, phase B, and phase C respectively; Obtain the highest sampling frequency f in the three-phase voltage signals respectively from the power node data s ; Based on the sampling frequency f s align the frequencies of the three-phase voltage signals to obtain the sampling interval T s = 1 / f s ; Obtain the phase A, phase B, and phase C in the three-phase voltage signal after sampling and alignment, which are V a (t), V b (t), and V c (t); The sampling points of phase A, phase B, and phase C in the three-phase voltage signal are respectively denoted as V a (n), V b (n), and V c (n), where n = 1, 2,..., N - 1, and N is the total number of sampling points of V a (t), and t = n·T s ; Step S103: Based on phase A, perform time delay compensation on phase B and phase C. The specific process is: Estimate the time delay of phase C with respect to phase A. The specific process is as follows: Obtain the cross-correlation sequence R (a,c) [d] of phase A and phase C; Based on the cross-correlation sequence R (a,c) [d], obtain the maximum value d of the d max , estimate the time delay τ of the phase C relative to the phase A (a,c) = d max ·T s ; Estimate the time delay τ of phase B relative to phase A (a,b) ; Perform time delay compensation on the phase C to obtain V´ c (n), and the specific formula is V´ c (n) = V c (n + τ (a,c) / T s ); Perform time delay compensation on the said Phase B to obtain V´ b (n); Step S104: Perform Fourier transforms on V a (n), V' b (n) and V' c (n) of the three-phase voltage signals respectively to obtain V a [k], V' b [k] and V' c [k]; Obtain the V a [k], V' b [k] and V' c [k] of the fundamental frequency index k0, and obtain the phases θ a , θ b and θ c ; Obtain the phase difference Δθ between the phase A and the phase B (a,b) = θ b - (θ a - 2π / 3), and obtain the phase difference Δθ between the phase A and the phase C (a,c) = θ c - (θ a + 2π / 3); Perform phase compensation on the phase B and the phase C respectively to obtain V´ （△，b） (n) and V´ （△，c） (n), where phase compensation is performed on the phase B to obtain V´ （△，b） [k], perform an inverse Fourier transform on V´ （△，b） [k] to obtain V´ （△，b） (n); Step S105: Obtain the power node data after data synchronization alignment, and suppress the noise of the power node data to obtain target power node data.

3. A power quality detection method for ensuring the node characteristics of a power system according to claim 2, characterized in that The step S200 includes: Step S201: Obtain the target power node data and perform harmonic analysis on the target power node data to obtain the total harmonic distortion rates of the three-phase voltage signals and three-phase current signals in the target power node data. Among them, the specific analysis process for the three-phase voltage signals in the target power node data is: Perform Fourier transform on each phase signal in the three-phase voltage signals in the target power node data to obtain the frequency-domain complex numbers of the three-phase voltage signals; Extract the harmonic parameters of the three-phase voltage signal to obtain the effective value V of phase A in the three-phase voltage signal a h , and the specific acquisition process is as follows: Obtain the complex number X in the frequency domain of phase A (a,h) (k), where f k = k·f s / N, N is the total number of sampling points of phase A, and f s is the highest sampling frequency in the three-phase voltage signals; Obtain the amplitude Ah of the h-th harmonic of the phase A h =(2·|X (a,h) (k)|) / N, obtain the effective value Vh of the h-th harmonic of the phase A a h =Ah h / 2 1 / 2 ; Obtain the harmonic distortion rate T of phase A in the three-phase voltage signal a v ; Obtain the harmonic distortion rate T of phase B and phase C in the three-phase voltage signal b v and the harmonic distortion rate T c v , and obtain the total harmonic distortion rate T of the three-phase voltage signal v = max{T a v , T b v , T c v}; Step S202: Perform symmetrical component decomposition on the three-phase voltage signals and three-phase current signals in the target power node data. Among them, the process of performing symmetrical component decomposition on the three-phase voltage signals is: Obtain the effective values V of the fundamental voltages of phase B and phase C in the target power node data b 1 and V c 1, perform symmetrical component decomposition on the three-phase voltage signals in the target power node data to obtain the positive-sequence voltage component V + 1 and the negative-sequence voltage component V - 1; Calculate the unbalance degree VUF of the three-phase voltage signal = (|V + 1| / |V - 1|) · 100%; Step S203: Track the frequency of the power system nodes. Among them, the process of tracking the frequency of the three-phase voltage signals in the power system nodes is: Obtain the instantaneous values of phase A, phase B, and phase C in the three-phase voltage signal, convert the three-phase voltage signal into a stationary coordinate system, and extract the instantaneous phase angle θ of the three-phase voltage signal from the stationary coordinate system v (t); Through the instantaneous phase angle θ v Calculate the instantaneous frequency f of the three-phase voltage signal v (t): ， Obtain the fundamental frequency f0 in the power system node, and calculate the frequency deviation △f of the three-phase voltage signal in the power system node v (t)=f v (t)-f0; Step S204: Use the total harmonic distortion rates, unbalance degrees, and frequency deviations of the three-phase voltage signals and three-phase current signals in the target power node data as the key indicators of the power system nodes; Obtain the data of each key index in the three-phase voltage signal and the three-phase current signal in the power system node and gather them to obtain the key index data of the power system node.

4. A power quality detection method for ensuring the node characteristics of a power system according to claim 3, characterized in that, The step S300 includes: Step S301: Obtain the key index data in the power system node, and obtain the data of each key index in the power system node from the key index data; Step S302: Obtain the key index range data of the power system node, where the key index range data includes the preset ranges of each key index in the power system node; Detect the power quality of the power system node. The specific detection process is as follows: When the value of a certain key index is not within the preset range of the key index range data, record the certain key index as an abnormal key index, and determine that there is power quality abnormality in the power system node in the current cycle; Step S303: When there is an abnormal key index in the power system node, record the power system node as an abnormal power system node, and obtain the data of each abnormal key index in the abnormal power system node to obtain abnormal key index data.

5. A power quality detection method for ensuring the node characteristics of a power system according to claim 4, characterized in that, The step S400 includes: Step S401: Obtain the abnormal key index data of the abnormal power system node, and obtain the root cause discrimination data of the abnormal power system node, where the root cause discrimination data includes the preset ranges of each key index in each abnormal root cause; Step S402: Analyze the root cause affecting the power quality of the power system node to obtain quality impact root cause data. The specific analysis process is as follows: Obtain the data of each abnormal key index in the abnormal power system node from the abnormal key index data. When the maximum value and the minimum value of a certain abnormal key index in the abnormal power system node are within the preset range of the certain abnormal key index in a certain abnormal root cause, determine that the certain abnormal key index is the abnormal key index related to the certain abnormal root cause; Obtain the total number Q of abnormal key indicators related to a certain abnormal root cause among the abnormal key indicator data sum , and obtain the total number Q sum The ratio between the total number of each abnormal key indicator in the abnormal key indicator data is used to obtain the probability value of a certain abnormal root cause in the abnormal power system node; Obtain the probability values of each abnormal root cause in the abnormal power system node. When the probability value of a certain abnormal root cause is greater than the preset probability threshold, record the certain abnormal root cause as the target abnormal root cause, and obtain and gather several target abnormal root causes in the abnormal power system node to obtain target root cause data; Step S403: Obtain several target abnormal root causes in the target root cause data, and based on the maintenance equipment required for the several target abnormal root causes, dispatch the maintenance personnel in the area where the abnormal power system node is located to carry the maintenance equipment to repair the power system node.

6. A power quality detection system for ensuring the node characteristics of a power system, which is used to execute a power quality detection method for ensuring the node characteristics of a power system according to any one of claims 1-5, characterized in that, The system includes a data synchronization module, a key index acquisition module, a power quality detection module, and a node maintenance module; The data synchronization module is used to synchronize and align the power node data in the power system node, and suppress the noise in the power node data after data synchronization and alignment to obtain target power node data; The key index acquisition module is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system nodes to obtain the key index data of the power system nodes; The power quality detection module is used to detect the power quality of the power system nodes, analyze the abnormal conditions of the power quality of the power system nodes, and obtain the abnormal key index data of the abnormal power system nodes; The node maintenance module is used to analyze the root causes affecting the power quality of the power system nodes to obtain target root cause data, and dispatch maintenance personnel in the area where the abnormal power system nodes are located to repair the power system nodes according to the target root cause data.

7. The power quality detection system for guaranteeing the node characteristics of a power system according to claim 6, wherein The data synchronization module includes a data acquisition unit and a data synchronization unit; The data acquisition unit is used to acquire the power node data of the power system nodes, and the power node data includes the data corresponding to the three-phase voltage signals and three-phase current signals of the power system nodes in the current period; The data synchronization unit is used to synchronize and align the power node data, and suppress the noise of the power node data after data synchronization and alignment to obtain the target power node data.

8. A power quality detection system for ensuring the node characteristics of a power system according to claim 6, characterized in that, The key index acquisition module includes a data analysis unit and a key index acquisition unit; The data analysis unit is used to perform harmonic analysis and symmetrical component decomposition on the target power node data, and track the frequency of the power system nodes to obtain the total harmonic distortion rate, unbalance degree, and frequency deviation data of the three-phase voltage signals and three-phase current signals of the power system nodes; The key index acquisition unit is used to use the total harmonic distortion rate, unbalance degree, and frequency deviation of the three-phase voltage signals and three-phase current signals in the target power node data as the key indexes of the power system nodes, collect the data of each key index in the three-phase voltage signals and three-phase current signals in the power system nodes, and obtain the key index data of the power system nodes.

9. The power quality detection system for guaranteeing the node characteristics of a power system according to claim 6, wherein The power quality detection module includes a power quality detection unit; The power quality detection unit is used to acquire the key index data in the power system nodes, obtain the key index range data of the power system nodes, detect the power quality of the power system nodes, and obtain the abnormal key index data of the abnormal power system nodes.

10. A power quality detection system for ensuring the node characteristics of a power system according to claim 6, characterized in that, The node maintenance module includes a root cause analysis unit and a node maintenance unit; The root cause analysis unit is used to acquire the abnormal key index data of the abnormal power system nodes, analyze the root causes affecting the power quality of the power system nodes, and obtain the target root cause data; The node maintenance unit is used to dispatch maintenance personnel to repair the abnormal power system nodes according to the target root cause data.

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