阅读说明：本技术 电能质量在线监测装置接线错误自动检测与数据校正方法 (Method for automatically detecting wiring errors and correcting data of online power quality monitoring device ) 是由 刘亚丽 吕金炳 李国栋 杨维 刘创华 满玉岩 于光耀 李树鹏 胡晓辉 张野 汪颖 于 2019-09-19 设计创作，主要内容包括：本发明涉及一种电能质量在线监测装置接线错误自动检测与数据校正方法,其主要技术特点是：通过电能质量在线监测装置获取电压输入回路和电流输入回路的电压电流数据,根据电压电流数据判断判断A相电压是否正常,电压接线错误检测、判断得到电压误接线类型,电流接线错误检测、判断得到电流误接线类型,根据电压误接线类型对电压数据进行校正,根据电流误接线类型对电流数据进行校正,将检测或校正结果传给电能质量监测系统。本发明安装在线电能质量监测数据处理平台上,通过远端实现电能质量在线监测装置的接线错误的智能识别与数据校正功能,减少了由误接线带来的异常数据,降低人工排查误接线的成本与提高了误接线排查的效率。(The invention relates to a method for automatically detecting wiring errors and correcting data of an electric energy quality online monitoring device, which is mainly technically characterized by comprising the following steps of: the method comprises the steps of obtaining voltage and current data of a voltage input circuit and a current input circuit through an electric energy quality online monitoring device, judging whether A-phase voltage is normal or not according to the voltage and current data, detecting and judging a voltage wiring error to obtain a voltage miswiring type, detecting and judging a current miswiring type, correcting the voltage data according to the voltage miswiring type, correcting the current data according to the current miswiring type, and transmitting a detection or correction result to an electric energy quality monitoring system. The intelligent identification and data correction device is arranged on an online power quality monitoring data processing platform, and the intelligent identification and data correction functions of the power quality online monitoring device for wiring errors are realized through a remote end, so that abnormal data caused by the wrong wiring is reduced, the cost for manually checking the wrong wiring is reduced, and the efficiency for checking the wrong wiring is improved.)

1. A method for automatically detecting and correcting wiring errors of an on-line power quality monitoring device is characterized by comprising the following steps:

step 1, acquiring voltage and current data of a voltage input loop and a current input loop through an electric energy quality online monitoring device, and entering step 2;

step 2, judging whether the A phase voltage is normal or not according to the voltage and current data, if so, entering the next step, and if not, executing the step 7;

step 3, detecting and judging voltage wiring errors to obtain voltage wiring error types, and entering step 5;

step 4, detecting and judging current wiring errors to obtain current wiring error types, and entering step 6;

step 5, correcting the voltage data according to the voltage miswiring type detected in the step 3, and entering a step 7;

step 6, correcting the current data according to the current miswiring type detected in the step 4, and entering a step 7;

and 7, transmitting the detection or correction result to a power quality monitoring system.

2. The method for automatically detecting the wiring error and correcting the data of the power quality online monitoring device according to claim 1, characterized in that: the specific detection method in the step 2 comprises the following steps: selecting one power quality monitoring device in sequence, and confirming that the A-phase voltage loop of the monitoring device is not subjected to the wrong wiring condition by calculating the phase difference of the A-phase voltage of the monitoring device and the adjacent monitoring device; when the phase difference absolute value between the phase of the phase A and the phase of the phase A of the adjacent device is between 170 and 180 degrees, the phase of the phase A of the device is judged to be reversely connected; when the phase difference absolute value between the phase of the phase A voltage and the phase A of the adjacent device is 120 +/-10 degrees, the phase A voltage is judged to be in wrong wiring condition with the phase B, C; and when the A-phase voltage wiring of the device is correct, the next step is carried out, otherwise, the serial number of the device is recorded and fed back to the power quality monitoring system.

3. The method for automatically detecting the wiring error and correcting the data of the power quality online monitoring device according to claim 1, characterized in that: the specific implementation method of the step 3 is as follows: taking ten periodic wave data of three-phase voltage of the power quality monitoring device A, B, C at the same moment, detecting whether phase leakage or fault condition exists, if yes, feeding back to the power quality monitoring system, if no phase leakage or fault condition exists, decomposing a voltage signal by a symmetrical component method to obtain positive sequence, negative sequence and zero sequence voltage, and then judging by utilizing a voltage loop misconnection type judgment table: when the condition of wrong wiring occurs, recording the mark number of the monitoring device and the type of the wrong wiring of the voltage loop.

4. The method for automatically detecting the wiring error and correcting the data of the power quality online monitoring device according to claim 1, characterized in that: the specific implementation method of the step 4 comprises the following steps: taking ten cycle waveforms of three-phase current of the power quality monitoring device A, B, C at the same time as the voltage, and then executing the following steps:

the method includes the steps of performing discrete Fourier transform on three-phase current waveform data to obtain a frequency domain signal of current, and taking out fundamental wave vectorsAndand (3) solving A-phase positive sequence, negative sequence and zero sequence components by using a symmetric component transformation matrix: when negative sequence current componentWhen the per unit value is more than 0.5, the current is considered to have the condition of false connection, and the next step is carried out

Solving voltage fundamental wave vectorAs a standard, byPlus-minusAt 120 DEG to obtainAndtaking fundamental wave voltage vector as reference for current solution to obtain current fundamental wave vectorAndare respectively connected withAndthe vector included angle of (A);

and thirdly, obtaining the vector included angle relation of the second step, and comparing the current miswiring type table with the range judgment table to obtain the current miswiring type.

5. The method for automatically detecting the wiring error and correcting the data of the power quality online monitoring device according to claim 1, characterized in that: the specific implementation method of the step 5 is as follows: when the A-phase voltage is determined to be correct, if the opposite polarity and phase sequence problems of B, C two-phase voltages are detected, correcting the data by using a data correction mode of the error, wherein the correction mode is to perform phase transformation on the data, when the opposite polarity occurs, the 180-degree rotation of the vector is corresponding to the operation of data sampling points as inversion transformation, when the phase sequence error occurs, the forward or reverse rotation of the vector is corresponding to the 120-degree rotation of the data sampling points as translation transformation, and the number of the translation sampling points is n₁₂₀,n₁₂₀The calculation formula is as follows:

wherein f is_sThe sampling frequency of the device is shown, and f is the power frequency.

6. The method for automatically detecting the wiring error and correcting the data of the power quality online monitoring device according to claim 1, characterized in that: the specific implementation method of the step 6 comprises the following steps: and according to the type of the current miswiring, correcting the current data by utilizing a current loop miswiring phase sequence correction table, a current loop miswiring polarity correction table and a combination of the two correction tables.

Technical Field

The invention belongs to the technical field of power quality monitoring, and particularly relates to a method for automatically detecting wiring errors and correcting data of a power quality online monitoring device.

Background

China gradually advances from a large manufacturing country to a strong manufacturing country, and high-quality electric power is the fundamental guarantee of high-precision and high-technology industrial production, so that the problem of electric energy quality is a problem which is more and more concerned by people day by day. The power quality not only affects the safety and economy of the power grid enterprise, but also affects the product quality and equipment safety of the user product.

The Power Quality (PQ) indexes include voltage Quality, current Quality, Power supply Quality and Power consumption Quality, and include frequency deviation, voltage fluctuation and flicker, three-phase imbalance, transient or transient overvoltage, waveform distortion (harmonic), voltage sag, voltage interruption, voltage sag, Power supply continuity and the like. The main purposes of power quality level monitoring are to assess power quality, describe the overall performance of the power system, diagnose interference sources and maintain equipment, and describe certain types of power quality problems. The power quality monitoring points are usually arranged at key positions such as transformer substations and user power inlets. The specific investigation indexes comprise frequency deviation, voltage fluctuation and flicker, three-phase unbalance, instantaneous or transient overvoltage, waveform distortion (harmonic), voltage sag, interruption, transient rise, power supply continuity and the like, and the accurate calculation and the power quality analysis of the indexes depend on the correctness of sampling data of voltage and current.

The existing online monitoring device for power quality generally adopts a CORBA-based architecture scheme, a MAS-based architecture scheme, an open monitoring system architecture scheme and a scheduling system mode-based architecture scheme, and its general external terminal is shown in fig. 1. The current and voltage sampling circuits are shown by the dotted frame portions in the figure. When the power quality on-line monitoring device is installed, wiring errors can obviously affect the collected data, subsequent analysis is carried out on the data under the condition that the miswiring is not detected, and misleading results can be generated on the power quality analysis. The false wiring of the power quality on-line monitoring device can be divided into current loop false wiring and voltage loop false wiring, so that the false wiring types can be simply classified into voltage loop false wiring, current loop false wiring and mixed false wiring.

The following are described separately:

1. miswiring of a voltage loop: the voltage loop refers to a connection part of a voltage channel port of the electric energy quality on-line monitoring device and a monitoring point bus, input voltage can be phase voltage or line voltage according to different wiring modes, and the electric energy quality monitoring device converts the voltage into phase voltage. Three types of errors may occur during installation:

(1) the reverse connection of the voltage inlet and outlet wires and the reverse connection of the voltage transformer (the reverse connection of the same-name end) cause the reversal of the voltage polarity.

(2) Wrong connection positions occur among voltage transformers and among all phase wire inlet ends, so that phase sequence errors occur.

(3) Aliasing in both cases (1) and (2).

2. Miswiring of a current loop: the current loop refers to the connection part of a current channel port and a monitoring point bus of the online power quality monitoring device. The input current may be phase current or line current according to the wiring mode, and the power quality monitoring device converts the current into the phase current. Similar to the reason for miswiring of the voltage loop, three types of errors may occur during the installation process:

(1) the reverse connection of the current inlet and outlet wires and the reverse connection of the current transformer cause the reversal of the current polarity at the same-name end.

(2) Wrong connection positions occur among the current transformers and among the incoming line ends of all phases, so that phase sequence errors occur.

(3) Aliasing in both cases (1) and (2).

3. Mixed miswiring including both category 1 and 2 miswiring situations.

The error of the original data of the power quality monitoring device caused by the wiring error is difficult to be found under the general condition, and particularly, a network for installing the power quality on-line monitoring device is realized on a large scale. When the power quality original data is subsequently processed, abnormal data or data which seems wrong are often directly removed, and a lot of useful information is often missed; for most of the power quality monitoring devices, there is no effective method for detecting the faulty wiring, and a method for manually detecting each device or presetting a detection algorithm in the device obviously increases the cost for the monitoring equipment which is already installed in a large scale, and the detection of the faulty wiring is corrected by a person, so that the labor is still needed. Therefore, the remote dynamic detection of the original data by the power quality monitoring system is an effective solution to judge whether the wrong wiring of a certain power quality on-line monitoring device occurs.

Based on the analysis, in the installation process of the electric energy quality on-line monitoring device, because the number of the wiring is too large, the wiring error of the monitoring device can occur, so that the error of the original data of the electric energy quality data can occur, the error of the calculation of the electric energy quality index can be directly caused, and the electric energy quality control can be indirectly influenced. In the prior art, manual meter inspection is generally adopted or a detection algorithm is arranged in a meter, so that the efficiency is low and the cost is high for the former, and for the latter, an automatic identification and calibration technology is added during meter production to be a good method, but for a large-scale installed power quality monitoring device, the cost and the efficiency of equipment replacement and an embedded algorithm are greatly increased.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for automatically detecting and correcting the wiring error of an online power quality monitoring device, which can automatically identify the type of the wiring error of the online power quality monitoring device and correct the wrong voltage and current sampling data according to the type of the error.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a method for automatically detecting and correcting wiring errors of an on-line power quality monitoring device comprises the following steps:

step 1, acquiring voltage and current data of a voltage input loop and a current input loop through an electric energy quality online monitoring device, and entering step 2;

step 2, judging whether the A phase voltage is normal or not according to the voltage and current data, if so, entering the next step, and if not, executing the step 7;

step 3, detecting and judging voltage wiring errors to obtain voltage wiring error types, and entering step 5;

step 4, detecting and judging current wiring errors to obtain current wiring error types, and entering step 6;

step 5, correcting the voltage data according to the voltage miswiring type detected in the step 3, and entering a step 7;

step 6, correcting the current data according to the current miswiring type detected in the step 4, and entering a step 7;

and 7, transmitting the detection or correction result to a power quality monitoring system.

Further, the specific detection method in step 2 is as follows: selecting one power quality monitoring device in sequence, and confirming that the A-phase voltage loop of the monitoring device is not subjected to the wrong wiring condition by calculating the phase difference of the A-phase voltage of the monitoring device and the adjacent monitoring device; when the phase difference absolute value between the phase of the phase A and the phase of the phase A of the adjacent device is between 170 and 180 degrees, the phase of the phase A of the device is judged to be reversely connected; when the phase difference absolute value between the phase of the phase A voltage and the phase A of the adjacent device is 120 +/-10 degrees, the phase A voltage is judged to be in wrong wiring condition with the phase B, C; and when the A-phase voltage wiring of the device is correct, the next step is carried out, otherwise, the serial number of the device is recorded and fed back to the power quality monitoring system.

Further, the specific implementation method of step 3 is as follows: taking ten periodic wave data of three-phase voltage of the power quality monitoring device A, B, C at the same moment, detecting whether phase leakage or fault condition exists, if yes, feeding back to the power quality monitoring system, if no phase leakage or fault condition exists, decomposing a voltage signal by a symmetrical component method to obtain positive sequence, negative sequence and zero sequence voltage, and then judging by utilizing a voltage loop misconnection type judgment table: when the condition of wrong wiring occurs, recording the mark number of the monitoring device and the type of the wrong wiring of the voltage loop.

Further, the specific implementation method of step 4 is as follows: taking ten cycle waveforms of three-phase current of the power quality monitoring device A, B, C at the same time as the voltage, and then executing the following steps:

the method includes the steps of performing discrete Fourier transform on three-phase current waveform data to obtain a frequency domain signal of current, and taking out fundamental wave vectorsAndand (3) solving A-phase positive sequence, negative sequence and zero sequence components by using a symmetric component transformation matrix: when negative sequence current componentWhen the per unit value is more than 0.5, the current is considered to have the condition of false connection, and the next step is carried out

Solving voltage fundamental wave vectorAs a standard, byPlus or minus 120 DEG to obtainAndtaking fundamental wave voltage vector as reference for current solution to obtain current fundamental wave vectorAndare respectively connected withAndin the direction ofMeasuring the included angle;

and thirdly, obtaining the vector included angle relation of the second step, and comparing the current miswiring type table with the range judgment table to obtain the current miswiring type.

Further, the specific implementation method of step 5 is as follows: when the A-phase voltage is determined to be correct, if the opposite polarity and phase sequence problems of B, C two-phase voltages are detected, correcting the data by using a data correction mode of the error, wherein the correction mode is to perform phase transformation on the data, when the opposite polarity occurs, the 180-degree rotation of the vector is corresponding to the operation of data sampling points as inversion transformation, when the phase sequence error occurs, the forward or reverse rotation of the vector is corresponding to the 120-degree rotation of the data sampling points as translation transformation, and the number of the translation sampling points is n₁₂₀,n₁₂₀The calculation formula is as follows:

wherein f is_sThe sampling frequency of the device is shown, and f is the power frequency.

Further, the specific implementation method of step 6 is as follows: and according to the type of the current miswiring, correcting the current data by utilizing a current loop miswiring phase sequence correction table, a current loop miswiring polarity correction table and a combination of the two correction tables.

The invention has the advantages and positive effects that:

the invention is arranged on an online power quality monitoring data processing platform, realizes the intelligent identification and data correction functions of the wiring error of the online power quality monitoring device through a far end, adopts a pure algorithm technology, does not relate to the addition of hardware, carries out wrong wiring monitoring and identification on the data received by the online power quality monitoring data processing platform, corrects the power quality monitoring data according to the type of the wiring error, reduces abnormal data caused by the wrong wiring, reduces the cost of manually checking the wrong wiring and improves the efficiency of wrong wiring checking, more perfectly reduces the influence of the wiring error of the online power quality monitoring device on the original data and the subsequent power quality analysis work, and provides a new thought in the aspect of reducing the original error of the power quality monitoring data.

Drawings

FIG. 1 is a schematic diagram of a general external terminal of a conventional power quality monitoring device;

FIG. 2a is a three-type typical wiring diagram (three-phase three-wire star type wiring mode) of the existing power quality on-line monitoring device;

FIG. 2b is a typical wiring diagram of three types (three-phase three-wire triangular wiring mode) of the existing power quality on-line monitoring device;

FIG. 2c is a three-class typical wiring diagram (three-phase four-wire star type wiring mode) of the conventional power quality on-line monitoring device;

FIG. 3 is a flow chart of an automatic detection and correction algorithm for power quality miswiring of the present invention;

FIG. 4 is a vector relationship for the occurrence of a voltage loop miswire (knowing that the A-phase voltage is correct);

FIG. 5 is a schematic diagram of the relationship between three-phase voltage and current;

fig. 6 is a 48 type graph (6 x 8) of voltage miswiring.

Detailed Description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention can detect the false wiring types of three wiring modes of the power quality on-line monitoring device, wherein the three wiring modes comprise three-phase three-wire star type, three-phase three-wire triangle and three-phase four-wire star type wiring modes, which are respectively shown in fig. 2a, fig. 2b and fig. 2 c. The invention can rapidly perform table look-up judgment aiming at various wiring errors (mainly wiring errors of the incoming and outgoing lines of voltage and current and the secondary circuit of the mutual inductor) in the wiring process, identify the type of the wiring error, feed back the type of the miswiring according to the meter wiring mode, perform corresponding correction on the acquired data, and restore the real monitoring data of the power quality to the maximum extent.

In practical application, the invention is embedded into an online power quality monitoring data processing platform, remotely detects the power quality online monitoring device with wrong wiring in the whole network, judges the type of the wrong wiring and corrects the wrong data, thereby reducing the influence of the wrong wiring on subsequent power quality evaluation and analysis work. As shown in fig. 1, the external connection of the power quality online monitoring device comprises a voltage input loop (1), a current input loop (2), a network interface (3), a device working power supply (4), a switching value input interface (5), and ports (6, 7) for communication, time synchronization, grounding, debugging, shielding, etc., the front interface of the universal online power quality monitoring device comprises a signal indicator lamp, an operation key and a liquid crystal display, the internal hardware comprises a Digital Signal Processor (DSP), a Random Access Memory (RAM), a memory, a signal acquisition and transmission module, an input/output (I/O) control module and a data bus, and the architecture of the universal power quality monitoring system comprises a terminal monitoring unit, a communication service system, a database service system and an online power quality monitoring data processing platform.

The invention discloses a method for automatically detecting wiring errors and correcting data of an on-line power quality monitoring device, which is arranged on an on-line power quality monitoring data processing platform. The invention comprises the following steps:

step 1, acquiring voltage and current data of a voltage input loop and a current input loop through an electric energy quality online monitoring device.

In this step, the power quality on-line monitoring device collects corresponding voltage and current data through the transformer terminals connected to the voltage input circuit and the current input circuit.

Step 2, judging whether the A phase voltage is normal or not, wherein the specific method comprises the following steps:

as shown in fig. 3, it is first determined whether the effective value of the voltage of the phase a obtained by a voltage transformer of a selected power quality monitoring device belongs to a normal range under the voltage class, and the possibility of disconnection or cross-phase connection of the phase a is eliminated. Selecting a certain power quality monitoring device in sequence, selecting a power quality monitoring device electrically adjacent to the power quality monitoring device, and taking ten cycle sampling data (phase voltage) of A-phase voltage of the device and the adjacent device at the same moment, wherein the known voltage power frequency f is 50 +/-0.5 Hz, and the voltage sampling frequency of the device is assumed to be f_sNeglecting the high frequency part of the voltage, the sampling interval isFrom the start of the sampled waveform, findTo the zero crossing point of the first voltage positive period (from negative to positive) of each meter data, recording the data interval n between the zero crossing point of the positive half period of the voltage of the device and the adjacent power quality device_iAnd i represents an adjacent device, and then the phase difference is calculated, namely:

considering the power transmission longitudinal component delta V and the solving error of the power system, when the A-phase voltage loop is not in the wrong wiring condition, the angle theta is considered_iThe size is within +/-5 degrees; if the phase difference exceeds +/-5 degrees, the A-phase voltage is considered to have a wiring error, and the phase difference of the A-phase voltage of the device and an adjacent device is calculated to confirm that the A-phase voltage circuit of the device has no wrong wiring. When the phase difference absolute value between the phase of the phase A and the phase of the phase A of the adjacent device is between 170 and 180 degrees, the phase of the phase A of the device is judged to be reversely connected; and when the phase difference between the phase A voltage and the phase A of the adjacent device is 120 +/-10 degrees, the phase A voltage is judged to be in wrong wiring condition with the phase B, C. And when the A-phase voltage wiring of the device is correct, the next step is carried out, otherwise, the serial number of the device is recorded and fed back to the power quality monitoring system, the next step of analysis is not carried out, the types of the wrong wiring are reduced, and the algorithm efficiency is improved.

When the A-phase voltage of the selected power quality monitoring device is judged to be correct, voltage miswire and current miswire judgment and data correction are carried out on B, C-phase voltage and A, B, C-phase current of the device by taking the A-phase voltage as a reference, the two types of miswire judgment and data correction processes are independent, calculation can be carried out in parallel, and the steps 3 and 4, 5 and 6 are respectively utilized.

Step 3, voltage wiring error detection and judgment

Ten periodic wave data (phase voltage) of three-phase voltage of the device A, B, C at the same time are taken to detect whether phase leakage, faults and the like exist, and the voltage miswiring type is shown according to the vector relation in fig. 4. If the voltage signal exists, a monitoring and analyzing platform is fed back, if the voltage signal does not have the conditions of phase leakage, faults and the like, the voltage signal is decomposed by a symmetrical component method to obtain positive sequence, negative sequence and zero sequence voltages, and the method comprises the following specific steps:

1) and performing discrete Fourier transform (specifically FFT) on the three-phase voltage waveform data to obtain a frequency domain signal of the voltage signal. Each data converted is a voltage vector (complex form: a + jb) at the corresponding frequency of the point, and a voltage fundamental wave vector is taken out Anddefining a phase relation operator α:and (3) solving the A-phase positive sequence, negative sequence and zero sequence components by using a symmetrical component transformation matrix, namely:

if the negative sequence voltage and the zero sequence voltage are overlarge and the power system fault is eliminated, the step 2) is carried out, if the voltage and the zero sequence voltage are within the normal range, the voltage loop is considered to be normal in wiring, and the current is judged to be in wrong wiring. Theoretically, under normal conditions, the three phases of the power system are symmetrical, and the negative sequence and the zero sequence components are very small.

2) To be provided withAs a reference, findAre respectively connected withAnd (4) generating a voltage loop misconnection type judgment table by considering the error interval. And (4) quickly judging by using a judgment table as follows:

TABLE 1B, C PHASE VOLTAGE miswiring decision TABLE

And judging by using a phase difference lookup table, recording the label of the device and the wrong wiring type of the voltage loop when the wrong wiring condition occurs, and deducing the specific reason of the wrong wiring possibly occurring in the wiring mode according to the wiring wrong type of the device and by combining actual experience according to the wiring mode of the device.

Step 4, current wiring error detection and judgment

Taking ten cycle waveforms of three-phase current at the same time as the voltage, carrying out FFT transformation in the same way, taking fundamental current vectors, and carrying out symmetrical component method decomposition, and the method comprises the following specific steps:

1) and (3) performing discrete Fourier transform (specifically FFT) on the three-phase current waveform data to obtain a frequency domain signal of the current. Extracting fundamental wave vectorAndand (3) solving the A-phase positive sequence, negative sequence and zero sequence components by using a symmetrical component transformation matrix, namely:

when negative sequence current componentWhen the per unit value of (d) is greater than 0.5 (rated current is 1), it is considered that the current is erroneously connected, and step 2) is performed.

2) Using the voltage fundamental wave vector obtained in step 3) 1)Is a standard ofAndpossible miswiring conditions leading to vector errors), byPlus or minus 120 DEG to obtainAndand taking the fundamental voltage vector as a reference for current solution. In order to ensure the safe and reliable operation of the power grid, the power system puts corresponding requirements on the power factor of a user, the minimum power factor requirement in the power factor standard executed by a power customer is 0.8, the corresponding phase angle is about 36.87 degrees, so the current vector is within +/-36.87 degrees (lagging or leading) of the voltage vector, the power factor of the power quality monitoring point of the whole system is more than 0.8, the range is +/-40 degrees in order to avoid errors, and the relation between the voltage and the current is schematically shown in figure 5. There may be two types of polarity and phase sequence errors for the current, where there are 6 types of opposite polarities (± Ia, ± Ib, ± Ic, total 2 × 2 × 2 ═ 8 types), and there are 6 types of phase sequence (such as ABC, ACB, BCA, etc.), there are 48 types of wiring errors (including one of the normal cases) combined, and all possible combinations are shown in fig. 6 (the asterisks indicate the normal cases, the first row is a 6 type current phase sequence, the first column is a 8 type current positive or negative polarity, and the rest are combinations). Calculating the current fundamental wave vectorAndare respectively connected withAndthe vector angle of (c).

3) Obtaining the included angle relation of the step 2), and comparing the current misconnection type table (table 2) with the range judgment table (table 3), wherein the table is as follows:

TABLE 2 type of miswire connection

Note: the first row is of different current phase sequence (6 kinds), and the first column is of current plus-minus polarity (8 kinds). -a represents a polarity reversal.

TABLE 3 phase determination Range of Current misconnection types

Note: theta_A、θ_BAnd theta_CRespectively, represent the angular difference between the current fundamental component and the corresponding voltage fundamental component.

And 3) finishing the judgment of the current miswiring and feeding back the result.

The above-described determination method is suitably used for the following systems:

a. the actual power flow is always unidirectional, i.e. there is no apparent distributed power connection at one or both stages.

b. The power factor is greater than about 0.8 (36.87) lead or lag.

c. The three-phase power factors are similar.

Step 5, correcting voltage data

When the A-phase voltage is determined to be correct, if the fact that the polarities of the two-phase voltages are opposite and the phase sequence problem occurs is detected B, C, the data is corrected by the data correction method of the type of error. ThroughAnd 3, judging the voltage miswiring type, and then correcting the voltage. The correction mode is to perform phase transformation on the data, when the reverse polarity occurs, the rotation of the vector by 180 degrees corresponds to the operation of data sampling points as reverse transformation, when the phase sequence is wrong, the forward or reverse rotation of the vector by 120 degrees corresponds to the translation transformation of the data sampling points, and the number of the translation sampling points is n₁₂₀,n₁₂₀The calculation is as follows:

wherein f is_sThe sampling frequency of the device is shown, and f is the power frequency. The list of data corrections for various types of voltage miswiring is as follows:

TABLE 4 correction table for miswiring of voltage loop

Note: the condition of wrong wiring of the single-phase voltage sequence rarely occurs, so that no consideration is given. The left-right translation is based on the phase voltage A, and the phase data A are arranged from left to right in time sequence.

Step 6, correcting current data

After the step 4, the type of the current miswiring is judged, the current data correction is carried out by using a correction method similar to voltage, the correction tables are shown in tables 5 and 6, two types of polarity inversion and phase sequence error are arranged in series, the mixed condition is the superposition of the two types of correction methods, the polarity inversion first step is defaulted during the superposition, and the phase sequence correction is the second step.

TABLE 5 Current Loop misconnection correction Table (phase sequence correction)

Note: reverse operation as I, translate to the leftPoint manipulation as II, translation to the rightThe point operation is III and no operation is IV.

TABLE 6 correction of misconnection of current loop (polarity correction)

Note: reverse operation as I, translate to the leftPoint manipulation as II, translation to the rightThe point operation is III and no operation is IV.

And 7, after correction is completed, feeding back the voltage and current misconnection type and the equipment number to the power quality monitoring system, carrying out misconnection detection on the next power quality online monitoring device, and executing the steps again. The overall algorithm flow is shown in fig. 6, and when the wiring of the a-phase voltage is confirmed to be correct, the judgment of voltage miswiring and current miswiring are calculated in parallel.

The invention is installed in an embedded online power quality monitoring data processing platform, the software processing flow is shown in figure 3, and the processing flow comprises the steps of voltage acquisition loop miswiring judgment, current loop miswiring judgment and data correction:

and (3) a voltage loop wiring judgment algorithm: the wrong wiring detection of the voltage loop is particularly important as a reference for current calibration, and whether the wiring of the phase A is correct or not is a key point, so that whether the wiring of the phase A voltage signal is correct or not can be determined by comparing the information processing and analyzing platform with an adjacent monitoring device, and otherwise, the wrong wiring detection of the voltage loop cannot be used as a reference for other phases. If the phase A is judged to be in wrong wiring by comparing the phase A with other monitoring points, the phase A of the device is calibrated by the positions of phase A voltages of other monitoring devices, and then the next step is carried out; if the phase A is accurate, B, C phase voltage is judged (referring to the wrong connection type of the voltage loop in figure 4; the wrong detection flow is shown in figure 3; and the wrong connection type of the voltage loop is judged according to the table 1). If the A-phase wiring error of the adjacent device is found in the first step of the A-phase voltage monitoring process, the device is subjected to false wiring detection and data calibration after the detection algorithm is realized, and then B, C-phase voltage acquisition signals are judged.

Referring to fig. 6, a current loop detection algorithm flow and a typical wrong phase diagram, an a-phase voltage is used as a reference phase, a vector is established according to B, C voltage sampling data, whether a wrong wiring condition exists between B, C phases is judged according to a phase relation of the vector, if a difference between a B, C two-phase voltage vector and a correct phase sequence position angle determined by the a phase exceeds 15 degrees, a wiring error of a certain phase can be judged, positions and error ranges of various wrong wirings are preset, and the wrong wiring type is determined through quick query; and the current vector still takes the A-phase voltage as a reference, and the phase of the vector is quickly compared with a preset wiring error phase template to determine the type of the wiring error.

Referring to typical concept of wrong wiring correction in tables 4, 5 and 6, the data correction technology carries out reverse reduction by judging specific wrong wiring types and utilizing the effect of original data caused by wrong wiring, takes certain error factors into consideration, carries out data correction by means of time series data processing such as phase shift and inversion, finally records the information of the wrong wiring device and the data reduction condition, and feeds back the information to a monitoring center and a manufacturer.

Nothing in this specification is said to apply to the prior art.

It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.