A power quality detection method and system for ensuring power system node characteristics

Abstract

The present invention discloses a power quality detection method and system for ensuring the characteristics of power system nodes, which relates to the technical field of power quality detection. The method and system include performing data synchronization alignment on power node data and suppressing noise in the power node data after data synchronization alignment; performing harmonic analysis and symmetrical component decomposition on target power node data and tracking the frequency of the power system nodes; detecting the power quality of the power system nodes and analyzing the abnormal power quality conditions of the power system nodes; obtaining abnormal key indicator data of abnormal power system nodes, analyzing the root causes affecting the power quality of the power system nodes, obtaining target root cause data, and dispatching maintenance personnel to repair the abnormal power system nodes based on the target root cause data, thereby realizing rapid and accurate power quality detection of the power system nodes and also accelerating the maintenance efficiency of the power system nodes.

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 node characteristics of a power system. Background Art

[0002] In the power system, the detection of power quality of power system nodes is the core requirement to ensure the safe and reliable operation of the system. Once there is a problem with the power quality of the power system nodes, it will not only cause losses in the operation of power equipment, but may also cause problems with the power equipment. Moreover, the power quality problems of the power system nodes will also be transmitted through the power grid, thereby 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 the power system nodes.

[0003] At present, 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 by fast Fourier transform and then the harmonic and interharmonic components are analyzed. However, this method has high requirements on signal periodicity, requires the signal period to be stable, and has weak analysis capabilities for dynamic changes or transient changes in power system nodes; 2. Effective value detection method, by calculating the effective value of the voltage or current in the power system node to judge the voltage or current situation, but this method requires multiple cycles of calculation and cannot respond quickly to the situation of the power system node; therefore, there is currently a lack of an effective method for detecting the power quality in the 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 characteristics of power system nodes, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for detecting power quality to ensure the characteristics of power system nodes, the method comprising:

[0006] Step S100: acquiring power node data of a power system node, performing data synchronization alignment on the power node data, and suppressing noise in the power node data after the data synchronization alignment to obtain target power node data;

[0007] Step S200: acquiring target power node data, performing harmonic analysis and symmetrical component decomposition on the target power node data, and tracking the frequency of the power system node to obtain key indicator data of the power system node;

[0008] Step S300: Acquire key indicator data, acquire key indicator range data of power system nodes, detect power quality of power system nodes, and analyze abnormal power quality conditions of power system nodes to obtain abnormal key indicator data of abnormal power system nodes;

[0009] Step S400: Acquire abnormal key indicator data of abnormal power system nodes, analyze the root causes affecting the power quality of the power system nodes, obtain target root cause data, and dispatch maintenance personnel to repair the abnormal power system nodes based on the target root cause data.

[0010] Furthermore, step S100 includes:

[0011] Step S101: acquiring power node data of a power system node, the power node data including data corresponding to a three-phase voltage signal and a three-phase current signal of the power system node in a current cycle;

[0012] Step S102: performing data synchronization alignment on the power node data, wherein the process of performing data synchronization alignment on the three-phase voltage signal data in the power node data is as follows:

[0013] The three-phase voltage signals are obtained from the power node data and recorded as phase A, phase B and phase C respectively;

[0014] The highest sampling frequency f is obtained from the power node data respectively in the three-phase voltage signal s ;

[0015] With sampling frequency f s As a benchmark, align the frequencies of the three-phase voltage signals and obtain the sampling interval T of the three-phase voltage signals. s =1 / f s ;

[0016] The phase A, phase B and phase C of the sampled and aligned three-phase voltage signal are V a (t), V b (t) and V c (t);

[0017] The sampling points of phase A, phase B and phase C in the three-phase voltage signal are recorded as V a (n), V b (n) and V c (n), where n=1, 2, ..., N-1, and N is V a The total number of sampling points of (t), t=n·T s ;

[0018] Step S103: Based on phase A, perform time delay compensation on phases B and C. The specific process is as follows:

[0019] Estimate the time delay of phase C relative to phase A. The specific process is: obtain the cross-correlation sequence R of phase A and phase C (a,c) [d];

[0020] Based on the cross-correlation sequence R (a,c) [d], get the maximum value d of d max , estimate the time delay τ of phase C relative to phase A (a,c) =d max ·T s ;

[0021] Estimate the time delay τ of phase B relative to phase A (a,b) ;

[0022] Perform time delay compensation on phase C to obtain V´ c (n), the specific formula is V´ c (n)=V c (n+τ (a,c) / T s );

[0023] Perform time delay compensation on phase B to obtain V´ b (n);

[0024] Step S104: V of the three-phase voltage signal is respectively a (n), V´ b (n) and V´ c (n) Perform Fourier transform to get V a [k]、V´ b [k] and V´ c [k];

[0025] Get V respectively a [k]、V´ b [k] and V´ c The fundamental frequency index k0 of [k] is used to obtain the phase θ of phase A, phase B and phase C. a ,θ b and θ c ;

[0026] Get the phase difference △θ between phase A and phase B (a,b) =θ b -(θ a -2π / 3), obtain the phase difference △θ between phase A and phase C (a,c) =θ c -(θ a +2π / 3);

[0027] Perform phase compensation on phase B and phase C respectively to obtain V´ （△，b） [k] and V´ （△，c） [k], where V´ is obtained by phase compensation of phase B. （△，b）[k], for V´ （△，b） [k] performs inverse Fourier transform to obtain V´ （△，b） (n);

[0028] Step S105: acquiring the power node data that has undergone data synchronization alignment, and suppressing the noise of the power node data to obtain target power node data;

[0029] In the above steps, the power node data of the power system nodes are synchronized and aligned, so that the phase relationship of the three-phase voltage and three-phase current in the power node data will not be distorted, and the regularity presented by the data will not be concealed, thereby making the subsequent processing results of the power node data more accurate, which is conducive to the subsequent detection of the power quality of the power system nodes.

[0030] Furthermore, step S200 includes:

[0031] Step S201: Acquire target power node data, perform harmonic analysis on the target power node data, and obtain the total harmonic distortion rate of the three-phase voltage signal and the three-phase current signal in the target power node data. The specific analysis process of the three-phase voltage signal in the target power node data is as follows:

[0032] Performing Fourier transform on each phase signal in the three-phase voltage signal in the target power node data to obtain a frequency domain complex number of the three-phase voltage signal;

[0033] Extract the harmonic parameters of the three-phase voltage signal and obtain the effective value V of phase A in the three-phase voltage signal. a h The specific acquisition process is:

[0034] Get the frequency domain complex number X of phase A (a,h) (k), where f k =k·f s / N, N is the total number of sampling points of phase A, f s It is the highest sampling frequency among the three-phase voltage signals;

[0035] Get 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 ;

[0036] Obtain the harmonic distortion rate T of phase A in the three-phase voltage signal a v ;

[0037] Obtain the harmonic distortion rate T of phase B and phase C in the three-phase voltage signal b v and harmonic distortion rate T 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};

[0038] Step S202: performing symmetrical component decomposition on the three-phase voltage signal and the three-phase current signal in the target power node data. The process of performing symmetrical component decomposition on the three-phase voltage signal is as follows:

[0039] Get the effective value V of the fundamental voltage 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 signal in the target power node data to obtain the voltage positive sequence component V in the target power node data. + 1 and the negative sequence voltage component V - 1;

[0040] Calculate the unbalance degree of the three-phase voltage signal VUF=(|V + 1| / |V - 1|)·100%;

[0041] Step S203: Tracking the frequency of the power system node. The process of tracking the frequency of the three-phase voltage signal in the power system node is as follows:

[0042] 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);

[0043] By the instantaneous phase angle θ v (t) Calculate the instantaneous frequency f of the three-phase voltage signal v (t):

[0044] ,

[0045] 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;

[0046] Step S204: using the total harmonic distortion rate, unbalance and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as key indicators of the power system node;

[0047] The data of various key indicators of the three-phase voltage signal and the three-phase current signal in the power system node are obtained and collected to obtain the key indicator data of the power system node.

[0048] Furthermore, step S300 includes:

[0049] Step S301: Acquire key indicator data in the power system node, and acquire data of various key indicators in the power system node from the key indicator data;

[0050] Step S302: Acquire key indicator range data of the power system node, where the key indicator range data includes preset ranges of various key indicators within the power system node;

[0051] The power quality of the power system nodes is detected. The specific detection process is as follows:

[0052] When the value of a key indicator is not within the preset range of the key indicator range data, the key indicator is marked as an abnormal key indicator, and it is determined that the power system node has power quality abnormality in the current cycle;

[0053] Step S303: When an abnormal key indicator exists in the power system node, the power system node is recorded as an abnormal power system node, and data of various abnormal key indicators in the abnormal power system node are acquired to obtain abnormal key indicator data.

[0054] Furthermore, step S400 includes:

[0055] Step S401: Acquire abnormal key indicator data of an abnormal power system node, and acquire root cause identification data of the abnormal power system node, wherein the root cause identification data includes preset ranges of key indicators of various abnormal root causes;

[0056] Step S402: Analyze the root causes that affect the power quality of power system nodes and obtain quality-affecting root cause data. The specific analysis process is as follows:

[0057] Acquire data of various abnormal key indicators in the abnormal power system node from the abnormal key indicator data, and determine that the abnormal key indicator is a related abnormal key indicator of the abnormal root cause when the maximum value and the minimum value of a certain abnormal key indicator in the abnormal power system node are within a preset range of a certain abnormal key indicator in a certain abnormal root cause;

[0058] Get the total number of abnormal key indicators related to a certain abnormal root cause in the abnormal key indicator data Q sum , get the total number of items Q sum The probability value of a certain abnormal root cause in the abnormal power system node is obtained by comparing the ratio of the total number of each abnormal key indicator in the abnormal key indicator data to the total number of each abnormal key indicator.

[0059] Obtain the probability value of each abnormal root cause in the abnormal power system node. When the probability value of a certain abnormal root cause is greater than a preset probability threshold, record the abnormal root cause as the target abnormal root cause. Obtain and aggregate several target abnormal root causes in the abnormal power system node to obtain target root cause data.

[0060] Step S403: obtaining several items of abnormal root causes in the target root cause data, and dispatching maintenance personnel from the area where the abnormal power system node belongs to carry maintenance equipment to repair the power system node based on the maintenance equipment required by the several items of abnormal root causes.

[0061] 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;

[0062] A data synchronization module is used to synchronize the power node data in the power system nodes and suppress the noise in the power node data after the data synchronization alignment to obtain the target power node data;

[0063] Key indicator acquisition module, used to perform harmonic analysis and symmetrical component decomposition on target power node data, and track the frequency of power system nodes to obtain key indicator data of power system nodes;

[0064] The power quality detection module is used to detect the power quality of the power system nodes, analyze the abnormal power quality conditions of the power system nodes, and obtain abnormal key indicator data of the abnormal power system nodes;

[0065] The node maintenance module is used to analyze the root causes that affect the power quality of the power system nodes, obtain target root cause data, and dispatch maintenance personnel in the area where the abnormal power system node belongs to repair the power system node based on the target root cause data.

[0066] Furthermore, the data synchronization module includes a data acquisition unit and a data synchronization unit;

[0067] A data acquisition unit, configured to acquire power node data of a power system node, the power node data including data corresponding to a three-phase voltage signal and a three-phase current signal of the power system node in a current cycle;

[0068] The data synchronization unit is used to perform data synchronization alignment on the power node data and suppress the noise of the power node data after the data synchronization alignment to obtain the target power node data.

[0069] Furthermore, the key indicator acquisition module includes a data analysis unit and a key indicator acquisition unit;

[0070] A 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 node to obtain the total harmonic distortion rate, imbalance and frequency deviation data of the three-phase voltage signal and three-phase current signal of the power system node;

[0071] The key indicator acquisition unit is used to take the total harmonic distortion rate, imbalance and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as the power system node and the key indicator of the power system node, and to collect the data of various key indicators in the three-phase voltage signal and the three-phase current signal in the power system node to obtain the key indicator data of the power system node.

[0072] Furthermore, the power quality detection module includes a power quality detection unit;

[0073] The power quality detection unit is used to obtain key indicator data in the power system nodes, obtain key indicator range data of the power system nodes, detect the power quality of the power system nodes, and obtain abnormal key indicator data of abnormal power system nodes.

[0074] Furthermore, the node maintenance module includes a root cause analysis unit and a node maintenance unit;

[0075] A root cause analysis unit is used to obtain abnormal key indicator data of abnormal power system nodes, analyze the root causes affecting the power quality of power system nodes, and obtain target root cause data;

[0076] The node maintenance unit is used to dispatch maintenance personnel to repair abnormal power system nodes based on the target root cause data.

[0077] Compared with the prior art, the beneficial effects of the present invention are: the present invention realizes the effective detection of the power quality of the power system nodes, and in the power quality detection of the power system nodes, the problem of data misalignment in the acquired power node data is taken into consideration. Therefore, the three-phase voltage and three-phase current in the power node data are aligned respectively to ensure the accuracy of subsequent analysis, and the key indicators for judging the power quality are subsequently analyzed by the power node data. With the help of the specific data of the key indicators in the acquired power system nodes, the power quality in the power system nodes is detected and judged, so that the power quality of the power system nodes can be detected quickly and accurately, and the root causes affecting the power system nodes are analyzed so that the affected power system nodes can be quickly repaired, which effectively guarantees the power quality of the power system nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a method flow chart of a power quality detection method for ensuring power system node characteristics of the present invention;

[0079] Figure 2 It is a module schematic diagram of a power quality detection system for ensuring the node characteristics of a power system according to the present invention. DETAILED DESCRIPTION

[0080] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0081] Example: Figure 1-Figure 2 As shown, the present invention provides a technical solution, a power quality detection method for ensuring the characteristics of power system nodes, the method comprising:

[0082] Step S100: acquiring power node data of a power system node, performing data synchronization alignment on the power node data, and suppressing noise in the power node data after the data synchronization alignment to obtain target power node data;

[0083] Wherein, step S100 includes:

[0084] Step S101: acquiring power node data of a power system node, the power node data including data corresponding to a three-phase voltage signal and a three-phase current signal of the power system node in a current cycle;

[0085] Step S102: performing data synchronization alignment on the power node data, wherein the process of performing data synchronization alignment on the three-phase voltage signal data in the power node data is as follows:

[0086] The three-phase voltage signals are obtained from the power node data and recorded as phase A, phase B and phase C respectively;

[0087] The highest sampling frequency f is obtained from the power node data respectively in the three-phase voltage signal s ;

[0088] With sampling frequency f s As a benchmark, align the frequencies of the three-phase voltage signals and obtain the sampling interval T of the three-phase voltage signals. s =1 / f s ;

[0089] The phase A, phase B and phase C of the sampled and aligned three-phase voltage signal are V a (t), V b (t) and V c (t);

[0090] The sampling points of phase A, phase B and phase C in the three-phase voltage signal are recorded as V a (n), V b (n) and V c (n), where n=1, 2, ..., N-1, and N is V a The total number of sampling points of (t), t=n·T s ;

[0091] Step S103: Based on phase A, delay compensation is performed on phases B and C. The specific process is as follows:

[0092] Estimate the time delay of phase C relative to phase A. The specific process is: obtain the cross-correlation sequence R of phase A and phase C (a,c) [d];

[0093] For example, the cross-correlation sequence R (a,c) The specific formula for [d] is:

[0094] ,

[0095] Where d is the time offset, d∈[-T / 2,T / 2], where T is the preset fundamental wave period in the power system node;

[0096] Based on the cross-correlation sequence R (a,c) [d], get the maximum value d of d max , estimate the time delay τ of phase C relative to phase A (a,c) =d max ·T s ;

[0097] For example, to get d max The specific formula is:

[0098] ,

[0099] Estimate the time delay τ of phase B relative to phase A (a,b) ;

[0100] Perform time delay compensation on phase C to obtain V´ c (n), the specific formula is V´ c (n)=V c (n+τ (a,c) / T s );

[0101] Perform time delay compensation on phase B to obtain V´ b (n);

[0102] Step S104: V of the three-phase voltage signal is respectively a (n), V´ b (n) and V´ c (n) Perform Fourier transform to get V a [k]、V´ b [k] and V´ c [k];

[0103] Get V respectively a [k]、V´ b [k] and V´ c The fundamental frequency index k0 of [k] is used to obtain the phase θ of phase A, phase B and phase C. a ,θ b and θ c ;

[0104] For example, the phase θ a The calculation formula is: a =arg(V a [k0]);

[0105] Get the phase difference △θ between phase A and phase B (a,b) =θ b -(θ a -2π / 3), obtain the phase difference △θ between phase A and phase C (a,c) =θ c -(θ a +2π / 3);

[0106] Perform phase compensation on phase B and phase C respectively to obtain V´ （△，b） [k] and V´ （△，c） [k], where V´ is obtained by phase compensation of phase B. （△，b） [k], for V´（△，b） [k] performs inverse Fourier transform to obtain V´ （△，b） (n);

[0107] For example, V （△，b） [k] The specific formula is: V´´ （△，b） [k]=V´ b [k]·e -j·△θ(a,c) ;

[0108] Step S105: acquiring the power node data that has undergone data synchronization alignment, and suppressing the noise of the power node data to obtain target power node data;

[0109] For example, methods for suppressing noise in power node data include using adaptive wavelet threshold denoising;

[0110] Step S200: acquiring target power node data, performing harmonic analysis and symmetrical component decomposition on the target power node data, and tracking the frequency of the power system node to obtain key indicator data of the power system node;

[0111] Wherein, step S200 includes:

[0112] Step S201: Acquire target power node data, perform harmonic analysis on the target power node data, and obtain the total harmonic distortion rate of the three-phase voltage signal and the three-phase current signal in the target power node data. The specific analysis process of the three-phase voltage signal in the target power node data is as follows:

[0113] Performing Fourier transform on each phase signal in the three-phase voltage signal in the target power node data to obtain a frequency domain complex number of the three-phase voltage signal;

[0114] Extract the harmonic parameters of the three-phase voltage signal and obtain the effective value V of phase A in the three-phase voltage signal. a h The specific acquisition process is:

[0115] Get the frequency domain complex number X of phase A (a,h) (k), where f k =k·f s / N, N is the total number of sampling points of phase A, f s It is the highest sampling frequency among the three-phase voltage signals;

[0116] Get 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 ;

[0117] Obtain the harmonic distortion rate T of phase A in the three-phase voltage signal a v ;

[0118] For example, calculate the harmonic distortion rate T of phase A a v The specific formula is:

[0119] ,

[0120] Where 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 voltage of phase A in the power system node;

[0121] Obtain the harmonic distortion rate T of phase B and phase C in the three-phase voltage signal b v and harmonic distortion rate T 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};

[0122] Step S202: performing symmetrical component decomposition on the three-phase voltage signal and the three-phase current signal in the target power node data. The process of performing symmetrical component decomposition on the three-phase voltage signal is as follows:

[0123] Get the effective value V of the fundamental voltage 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 signal in the target power node data to obtain the voltage positive sequence component V in the target power node data. + 1 and the negative sequence voltage component V - 1;

[0124] For example, the specific formula for symmetrical component decomposition of the three-phase voltage signal in the target power node data is:

[0125] ,

[0126] Where a=e j120° ; V0 is the voltage zero sequence component;

[0127] Calculate the unbalance degree of the three-phase voltage signal VUF=(|V + 1| / |V - 1|)·100%;

[0128] Step S203: Tracking the frequency of the power system node. The process of tracking the frequency of the three-phase voltage signal in the power system node is as follows:

[0129] 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);

[0130] For example, the conversion formula for converting a three-phase voltage signal into a stationary coordinate system is:

[0131] ,

[0132] Among them, v a (t), v b (t) and v c (t) Instantaneous values of phase A, phase B and phase C;

[0133] Extract the instantaneous phase angle θ of the three-phase voltage signal from the stationary coordinate system v (t):

[0134] ,

[0135] By the instantaneous phase angle θ v (t) Calculate the instantaneous frequency f of the three-phase voltage signal v (t):

[0136] ,

[0137] 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;

[0138] Step S204: using the total harmonic distortion rate, unbalance and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as key indicators of the power system node;

[0139] Acquire and aggregate the data of various key indicators of the three-phase voltage signal and the three-phase current signal in the power system node to obtain the key indicator data of the power system node;

[0140] Step S300: Acquire key indicator data, acquire key indicator range data of power system nodes, detect power quality of power system nodes, and analyze abnormal power quality conditions of power system nodes to obtain abnormal key indicator data of abnormal power system nodes;

[0141] Wherein, step S300 includes:

[0142] Step S301: Acquire key indicator data in the power system node, and acquire data of various key indicators in the power system node from the key indicator data;

[0143] Step S302: Acquire key indicator range data of the power system node, where the key indicator range data includes preset ranges of various key indicators within the power system node;

[0144] The power quality of the power system nodes is detected. The specific detection process is as follows:

[0145] When the value of a key indicator is not within the preset range of the key indicator range data, the key indicator is marked as an abnormal key indicator, and it is determined that the power system node has power quality abnormality in the current cycle;

[0146] Step S303: When an abnormal key indicator exists in the power system node, the power system node is recorded as an abnormal power system node, and data of various abnormal key indicators in the abnormal power system node are acquired to obtain abnormal key indicator data;

[0147] Step S400: Acquire abnormal key indicator data of abnormal power system nodes, analyze root causes affecting power quality of power system nodes, obtain target root cause data, and dispatch maintenance personnel to repair abnormal power system nodes based on the target root cause data;

[0148] Wherein, step S400 includes:

[0149] Step S401: Acquire abnormal key indicator data of an abnormal power system node, and acquire root cause identification data of the abnormal power system node, wherein the root cause identification data includes preset ranges of key indicators of various abnormal root causes;

[0150] For example, the root causes of various abnormalities include generator failure, cable insulation aging, etc.

[0151] Step S402: Analyze the root causes that affect the power quality of power system nodes and obtain quality-affecting root cause data. The specific analysis process is as follows:

[0152] Acquire data of various abnormal key indicators in the abnormal power system node from the abnormal key indicator data, and determine that the abnormal key indicator is a related abnormal key indicator of the abnormal root cause when the maximum value and the minimum value of a certain abnormal key indicator in the abnormal power system node are within a preset range of a certain abnormal key indicator in a certain abnormal root cause;

[0153] Get the total number of abnormal key indicators related to a certain abnormal root cause in the abnormal key indicator data Q sum , get the total number of items Q sum The probability value of a certain abnormal root cause in the abnormal power system node is obtained by comparing the ratio of the total number of abnormal key indicators in the abnormal key indicator data to the total number of abnormal key indicators.

[0154] Obtain the probability value of each abnormal root cause in the abnormal power system node. When the probability value of a certain abnormal root cause is greater than a preset probability threshold, record the abnormal root cause as the target abnormal root cause. Obtain and aggregate several target abnormal root causes in the abnormal power system node to obtain target root cause data.

[0155] Step S403: obtaining several items of abnormal root causes from the target root cause data, and dispatching maintenance personnel from the area where the abnormal power system node belongs to carry maintenance equipment to repair the power system node based on the maintenance equipment required by the several items of abnormal root causes;

[0156] For example, maintenance equipment includes reverse power protection measurement and control devices, automatic transfer switches and UPS hosts;

[0157] 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;

[0158] A data synchronization module is used to synchronize the power node data in the power system nodes and suppress the noise in the power node data after the data synchronization alignment to obtain the target power node data;

[0159] Key indicator acquisition module, used to perform harmonic analysis and symmetrical component decomposition on target power node data, and track the frequency of power system nodes to obtain key indicator data of power system nodes;

[0160] The power quality detection module is used to detect the power quality of the power system nodes, analyze the abnormal power quality conditions of the power system nodes, and obtain abnormal key indicator data of the abnormal power system nodes;

[0161] The node maintenance module is used to analyze the root causes that affect the power quality of power system nodes, obtain target root cause data, and dispatch maintenance personnel in the area where the abnormal power system node belongs to repair the power system node based on the target root cause data;

[0162] Among them, the data synchronization module includes a data acquisition unit and a data synchronization unit;

[0163] A data acquisition unit, configured to acquire power node data of a power system node, the power node data including data corresponding to a three-phase voltage signal and a three-phase current signal of the power system node in a current cycle;

[0164] A data synchronization unit is used to perform data synchronization alignment on the power node data and suppress noise in the power node data after data synchronization alignment to obtain target power node data;

[0165] Among them, the key indicator acquisition module includes a data analysis unit and a key indicator acquisition unit;

[0166] A 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 node to obtain the total harmonic distortion rate, imbalance and frequency deviation data of the three-phase voltage signal and three-phase current signal of the power system node;

[0167] a key indicator acquisition unit, configured to take the total harmonic distortion rate, unbalance, and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as the power system node and as the key indicator of the power system node, and to collect the data of various key indicators in the three-phase voltage signal and the three-phase current signal in the power system node to obtain the key indicator data of the power system node;

[0168] Wherein, the power quality detection module includes a power quality detection unit;

[0169] The power quality detection unit is used to obtain key indicator data in the power system nodes, obtain key indicator range data of the power system nodes, detect the power quality of the power system nodes, and obtain abnormal key indicator data of abnormal power system nodes;

[0170] Among them, the node maintenance module includes a root cause analysis unit and a node maintenance unit;

[0171] A root cause analysis unit is used to obtain abnormal key indicator data of abnormal power system nodes, analyze the root causes affecting the power quality of power system nodes, and obtain target root cause data;

[0172] The node maintenance unit is used to dispatch maintenance personnel to repair abnormal power system nodes based on the target root cause data.

[0173] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for detecting power quality to ensure the characteristics of power system nodes, characterized in that: The method comprises: Step S100: acquiring power node data of a power system node, performing data synchronization alignment on the power node data, and suppressing noise in the power node data after the data synchronization alignment to obtain target power node data; Step S200: acquiring the target power node data, performing harmonic analysis and symmetrical component decomposition on the target power node data, and tracking the frequency of the power system node to obtain key indicator data of the power system node; Step S300: Acquire the key indicator data, acquire 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 abnormal key indicator data of the abnormal power system node; Step S400: Acquire abnormal key indicator data of the abnormal power system node, analyze the root cause affecting the power quality of the power system node, obtain target root cause data, and dispatch maintenance personnel to repair the abnormal power system node based on the target root cause data.

2. A method for detecting power quality to ensure the characteristics of power system nodes according to claim 1, characterized in that: The step S100 includes: Step S101: acquiring power node data of the power system node, the power node data including data corresponding to the three-phase voltage signal and the three-phase current signal of the power system node in a current cycle; Step S102: performing data synchronization alignment on the power node data, wherein the process of performing data synchronization alignment on the three-phase voltage signal data in the power node data is as follows: Obtaining the three-phase voltage signals from the power node data and recording them as phase A, phase B and phase C respectively; The highest sampling frequency f in the three-phase voltage signal is obtained from the power node data. s ; At the sampling frequency f s As a reference, align the frequencies of the three-phase voltage signals to obtain the sampling interval T of the three-phase voltage signals. s =1 / f s ; Phase A, phase B and phase C of the three-phase voltage signal obtained by sampling and aligning 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 recorded as V a (n), V b (n) and V c (n), wherein n=1, 2, ..., N-1, and N is the V a The total number of sampling points of (t), t=n·T s ; Step S103: Based on the phase A, delay compensation is performed on the phase B and the phase C. The specific process is as follows: Estimate the time delay of phase C relative to phase A. The specific process is: obtain the cross-correlation sequence R of phase A and phase C (a,c) [d]; Based on the cross-correlation sequence R (a,c) [d], get the maximum value d of d max , 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 the phase C to obtain V´ c (n), the specific formula is V´ c (n)=V c (n+τ (a,c) / T s ); Perform time delay compensation on the phase B to obtain V´ b (n); Step S104: V of the three-phase voltage signal is respectively a (n), V´ b (n) and V´ c (n) Perform Fourier transform to get V a [k]、V´ b [k] and V´ c [k]; Get the V a [k]、V´ b [k] and V´ c [k] fundamental frequency index k0, obtain the phase θ of the phase A, the phase B and the phase C a ,θ b and θ c ; Get the phase difference Δθ between phase A and phase B (a,b) =θ b -(θ a -2π / 3), obtain the phase difference △θ 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） [k] and V´ （△，c） [k], wherein the phase compensation of the phase B is performed to obtain V´ （△，b） [k], for V´ （△，b） [k] performs inverse Fourier transform to obtain V´ （△，b） (n); Step S105: Acquire the power node data that has undergone data synchronization alignment, and suppress the noise of the power node data to obtain target power node data.

3. A method for detecting power quality to ensure the characteristics of power system nodes according to claim 2, characterized in that: The step S200 includes: Step S201: Acquire the target power node data, perform harmonic analysis on the target power node data, and obtain the total harmonic distortion rate of the three-phase voltage signal and the three-phase current signal in the target power node data. The specific analysis process of the three-phase voltage signal in the target power node data is as follows: Performing Fourier transform on each phase signal in the three-phase voltage signal in the target power node data to obtain a frequency domain complex number of the three-phase voltage signal; Extract the harmonic parameters of the three-phase voltage signal and obtain the effective value V of phase A in the three-phase voltage signal. a h The specific acquisition process is: Get the frequency domain complex number X of the phase A (a,h) (k), where f k =k·f s / N, N is the total number of sampling points of phase A, f s is the highest sampling frequency of the three-phase voltage signal; Get the amplitude A of the hth harmonic of the 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 the 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 harmonic distortion rate T 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: performing symmetrical component decomposition on the three-phase voltage signal and the three-phase current signal in the target power node data, wherein the process of performing symmetrical component decomposition on the three-phase voltage signal is as follows: Obtain the effective value V of the fundamental voltage of the phase B and the phase C in the target power node data b 1 and V c 1. Decompose the three-phase voltage signal in the target power node data into symmetrical components to obtain the voltage positive sequence component V in the target power node data. + 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: Tracking the frequency of the power system node, wherein 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 the phase A, the phase B, and the 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); By 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 Δf of the three-phase voltage signal in the power system node v (t) = f v (t)-f0; Step S204: using the total harmonic distortion rate, unbalance and frequency deviation of the three-phase voltage signal and the three-phase current signal in the target power node data as key indicators of the power system node; The data of various key indicators of the three-phase voltage signal and the three-phase current signal in the power system node are acquired and collected to obtain the key indicator data of the power system node.

4. A method for detecting power quality to ensure the characteristics of power system nodes according to claim 3, characterized in that: The step S300 includes: Step S301: Acquire key indicator data in the power system node, and acquire data of various key indicators in the power system node from the key indicator data; Step S302: Acquire key indicator range data of the power system node, wherein the key indicator range data includes preset ranges of various key indicators within the power system node; The power quality of the power system node is detected, and the specific detection process is as follows: When the value of a certain key indicator is not within the range preset in the key indicator range data, the certain key indicator is marked as an abnormal key indicator, and it is determined that the power system node has power quality abnormality in the current cycle; Step S303: When there is an abnormal key indicator in the power system node, the power system node is recorded as an abnormal power system node, and data of various abnormal key indicators in the abnormal power system node are acquired to obtain abnormal key indicator data.

5. A method for detecting power quality to ensure power system node characteristics according to claim 4, characterized in that: The step S400 includes: Step S401: Acquire abnormal key indicator data of an abnormal power system node, and acquire root cause identification data of the abnormal power system node, wherein the root cause identification data includes preset ranges of key indicators of various abnormal root causes; Step S402: Analyze the root causes that affect the power quality of the power system nodes to obtain quality-affecting root cause data. The specific analysis process is as follows: Acquire data of each abnormal key indicator in the abnormal power system node from the abnormal key indicator data, and determine that the abnormal key indicator is a related abnormal key indicator of the abnormal root cause when the maximum value and the minimum value of a certain abnormal key indicator in the abnormal power system node are within a preset range of the abnormal key indicator in a certain abnormal root cause; Obtain the total number of abnormal key indicators Q related to the abnormal root cause in the abnormal key indicator data sum , get the total number of items Q sum The probability value of the abnormal root cause of the abnormal power system node is obtained by calculating the ratio of the total number of abnormal key indicators in the abnormal key indicator data to the probability value of the abnormal root cause of the abnormal power system node; Obtaining probability values of the various abnormal root causes in the abnormal power system node; when the probability value of a certain abnormal root cause is greater than a preset probability threshold, recording the certain abnormal root cause as a target abnormal root cause; obtaining and aggregating several target abnormal root causes in the abnormal power system node to obtain target root cause data; Step S403: obtaining several target abnormal root causes in the target root cause data, and dispatching maintenance personnel from the area where the abnormal power system node belongs to carry the maintenance equipment to repair the power system node based on the maintenance equipment required by the several target abnormal root causes.

6. A power quality detection system for ensuring power system node characteristics, configured to execute a power quality detection method for ensuring power system node characteristics according to any one of claims 1 to 5, characterized in that: The system includes a data synchronization module, a key indicator acquisition module, a power quality detection module and a node maintenance module; The data synchronization module is used to perform data synchronization alignment on the power node data in the power system node, and suppress noise in the power node data after the data synchronization alignment to obtain target power node data; The key indicator 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 indicator data of the power system node; The power quality detection module is used to detect the power quality of the power system node, analyze the abnormal power quality status of the power system node, and obtain abnormal key indicator data of the abnormal power system node; The node maintenance module is used to analyze the root causes affecting the power quality of the power system node, obtain target root cause data, and dispatch maintenance personnel in the area where the abnormal power system node belongs to repair the power system node based on the target root cause data.

7. The power quality detection system for ensuring power system node characteristics according to claim 6, characterized in that: The data synchronization module includes a data acquisition unit and a data synchronization unit; The data acquisition unit is configured to acquire power node data of a power system node, wherein the power node data includes data corresponding to a three-phase voltage signal and a three-phase current signal of the power system node in a current cycle; The data synchronization unit is used to perform data synchronization alignment on the power node data and suppress noise of the power node data after the data synchronization alignment to obtain target power node data.

8. The power quality detection system for ensuring power system node characteristics according to claim 6, characterized in that: The key indicator acquisition module includes a data analysis unit and a key indicator 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 node to obtain data on the total harmonic distortion rate, imbalance and frequency deviation of the three-phase voltage signal and three-phase current signal of the power system node; The key indicator acquisition unit is used to take the total harmonic distortion rate, imbalance and frequency deviation of the three-phase voltage signal and three-phase current signal in the target power node data as the power system node and as the key indicator of the power system node, and to collect the data of various key indicators in the three-phase voltage signal and three-phase current signal in the power system node to obtain the key indicator data of the power system node.

9. The power quality detection system for ensuring power system node characteristics according to claim 6, characterized in that: The power quality detection module includes a power quality detection unit; The power quality detection unit is used to obtain key indicator data in the power system node, obtain key indicator range data of the power system node, detect the power quality of the power system node, and obtain abnormal key indicator data of the abnormal power system node.

10. The power quality detection system for ensuring power system node characteristics 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 obtain abnormal key indicator data of abnormal power system nodes, analyze the root causes affecting the power quality of the power system nodes, and obtain target root cause data; The node maintenance unit is used to dispatch maintenance personnel to repair the abnormal power system node according to the target root cause data.

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