Discrimination Method for Abnormal Wiring of High-Supply and Low-Metering Devices

Abstract

The object of the present invention is to provide a method for discriminating abnormal wiring of a high supply and low metering device. By using the exhaustive method, some indexes of 48 possible current wiring situations of the metering device are calculated, including the balance coefficient of the three-phase voltage on the high-voltage side, the power factor of the three-phase on the low-voltage side and its balance situation. Whether there is abnormal wiring is judged by analyzing the indexes. This method is only applicable to discriminating abnormal wiring of the metering device under the metering mode of high supply and low metering, and there are no current short-circuit and voltage open-phase faults in the metering device. Compared with the previous methods, it can reduce the probability of misjudgment and improve the accuracy of recognition.

Description

Technical Field

[0001] The present invention relates to the technical field of abnormal wiring discrimination of power grid metering devices, and particularly relates to a method for discriminating abnormal wiring of a high-voltage supply and low-voltage metering device. Background Art

[0002] With the development of the economy and the increase in electricity consumption, people have put forward higher and higher requirements for the normal operation of power grid metering devices. The metering data collected by the metering device can help relevant staff conduct important data analysis and ensure the normal collection of electricity bills. Therefore, it is very important to ensure the data quality of the metering data collected by the metering device. In actual production activities, some installation abnormalities may occur in the metering device, which will seriously affect the data quality of the metering data, making the metering data unreliable and further affecting subsequent data analysis and applications. Abnormal wiring of the metering device is a common abnormal problem, and there are special personnel in the power company to solve such problems on site. In this context, studying the method for discriminating abnormal wiring of the metering device to help staff discriminate abnormal wiring is of great significance.

[0003] Currently, most of the methods for discriminating abnormal wiring of metering devices are based on experience. Their basic idea is to give certain restrictions to the power factor angle according to experience, analyze the combination of three-phase voltage / current phases and phase differences under various wiring forms, and determine whether there is wiring error according to whether the current wiring situation is the most reasonable combination situation. These methods are relatively useful in most cases, but in actual situations, if the load situation is special, it is easy to cause misjudgment. Summary of the Invention

[0004] In order to reduce the probability of misjudgment, the present invention provides a more reliable method for discriminating abnormal wiring of a metering device for the metering method of high-voltage supply and low-voltage metering in a 10KV distribution network. It is to realize the discrimination of abnormal wiring of the metering device only for the metering method of high-voltage supply and low-voltage metering in a 10KV distribution network, and there are no current short-circuit and voltage phase-break faults in the metering device.

[0005] The present invention specifically proposes a method for discriminating abnormal wiring of a metering device that combines the three-phase balance degree of the high-voltage side with empirical rules for comprehensive determination, which is only applicable to the discrimination of abnormal wiring of the metering device under the metering method of high-voltage supply and low-voltage metering, and there are no current short-circuit and voltage phase-break faults in the metering device.

[0006] In the metering method of high-voltage power supply and low-voltage metering, it is not necessary to measure the three-phase voltage through a voltage transformer, but it is necessary to measure the three-phase current through a current transformer. Without considering short-circuit faults, the abnormal wiring of the current transformer includes incorrect connection positions between the incoming terminals of each phase, resulting in incorrect phase sequence, and reverse connection of the incoming and outgoing lines, resulting in reverse polarity of the current. Whether there is abnormal wiring in both the voltage circuit and the current circuit or only one of them, the final result is that the three-phase voltage does not match the three-phase current. Therefore, this method analyzes on the premise that the voltage circuit wiring is normal and only considers the abnormal wiring of the current circuit.

[0007] This solution calculates the indicators corresponding to 48 possible cases of current wiring, including the balance coefficient of the three-phase voltage on the high-voltage side, the power factor of the three phases on the low-voltage side and its balance situation. By analyzing the indicators, it is judged whether there is abnormal wiring and the ideal wiring situation is given. It should be noted that this ideal wiring situation is meaningful only when the voltage circuit wiring is normal. Compared with the previous methods, the outstanding advantage of the present invention is that it can reduce the probability of misjudgment and improve the efficiency of troubleshooting on site.

[0008] The technical solution specifically adopted by the present invention to solve its technical problems is:

[0009] A method for discriminating abnormal wiring of a high-voltage power supply and low-voltage metering device, characterized by comprising the following steps:

[0010] Step S1: Obtain the three-phase voltage and three-phase current data measured by the metering device under the metering method of high-voltage power supply and low-voltage metering of the 10KV distribution network;

[0011] Step S2: Identify the connection group of the distribution transformer to determine the connection group of the transformer corresponding to the data;

[0012] Step S3: Obtain the three-phase voltage phase and three-phase current phase;

[0013] Step S4: Use the exhaustive method to arrange and combine 48 possible cases of current wiring, and calculate the three indicators of the balance coefficient of the three-phase voltage on the high-voltage side, the power factor of phases A, B, and C, and the balance situation of the three-phase power factor in each case. Select one or more cases where the power factors of phases A, B, and C are all positive from the 48 cases for the next discrimination;

[0014] Step S5: According to the wiring situation and the results obtained in step S4, use the judgment rule to judge whether there is abnormal wiring in the power monitoring device.

[0015] Further, step S2 specifically includes the following steps:

[0016] Step S21: Calculate the unbalance degree ε of the three-phase current of the metering data i, specifically as follows:

[0017]

[0018] Among them, I A , I B , I C are the three-phase currents respectively;

[0019] Step S22: Select the metering and acquisition points with current unbalance degree greater than 10%, calculate their voltage unbalance degree and take the average value ε u , specifically as follows:

[0020]

[0021] In the above formula, U Ai , U Bi , U ci are the three-phase voltage values corresponding to the i-th metering and acquisition point with current unbalance degree greater than 10%, and n is the number of metering and acquisition points with current unbalance degree greater than 10%;

[0022] Step S23: Set a threshold value through experience. If the average voltage unbalance degree ε u is greater than this threshold value, it is determined that the connection group of the transformer corresponding to this metering data is Yyn0 type, otherwise it is Dyn11 type.

[0023] Furthermore, in step S3, in the case of AC sampling measurement, the three-phase voltage phase and the three-phase current phase can be directly obtained from the system.

[0024] Furthermore, in step S3, in the case of meter measurement, the three-phase voltage phase and the three-phase current phase are calculated and solved through the impedance angle.

[0025] Furthermore, for AC sampling measurement, if it is determined that the connection group of the transformer corresponding to the metering data is Dyn11 type, the three-phase voltage phase and the three-phase current phase are obtained through the following method:

[0026] On the premise of defaulting that the three-phase voltage phase is normal, let the three-phase voltage phase be α a , α b , α c , then α a = 360, α b = 240, α c = 120;

[0027] Let the angles between the three-phase voltage and the three-phase current be respectively The three-phase current phase is θ a , θ b , θ c , and the collected three-phase active power value is P a, P b , P b , the three - phase reactive power Q collected a , Q b , Q c . The calculation formula is as follows:

[0028]

[0029]

[0030] Furthermore, when arranging and combining 48 cases in step S4, the reverse - phase current is needed, and the data is processed as follows:

[0031] It is known that the three - phase current phase is θ a , θ b , θ c , it is necessary to perform reverse - phase processing on the current phase to obtain 3 current phasors opposite to the current phasor measured by the device. At this time, there are a total of 6 current phases, denoted as θ1, θ2, θ3, θ4, θ5, θ6; among them, θ1, θ2, θ3 are respectively equal to θ a , θ b , θ c , θ4 corresponds to θ1, θ5 corresponds to θ2, θ6 corresponds to θ3; among them, θ4, θ5, θ6 are obtained from θ1, θ2, θ3 through formula (5):

[0032]

[0033] Furthermore, step S4 specifically includes the following steps:

[0034] Step S41: Use the relevant principles of the transformer to deduce the high - voltage side voltage of the transformer from the measured value of the low - voltage side of the transformer:

[0035] 1) If the connection group of the transformer corresponding to the metering data is Dyn11 type, the influence of zero - sequence impedance does not need to be considered, and the calculation formula expressed in complex numbers is:

[0036] E a = U a + I a (R T + jX T ) (6)

[0037] E b = U b + I b (R T + jX T ) (7)

[0038] E c = U c + Ic (R T +jX T ) (8)

[0039] In the above formula, E a , E b , E c are the reduced values on the secondary side of the three-phase voltages on the high-voltage side of the transformer, R T is the reduced value of the equivalent resistance of the transformer on the secondary side, and X T is the reduced value of the equivalent reactance of the transformer on the secondary side;

[0040] 2) If the connection group of the transformer corresponding to the metering data is Yyn0 type, the influence of the zero-sequence impedance needs to be considered, and the calculation formula represented by complex numbers is:

[0041] E a = U a + I a (R T + jX T ) + U n (9)

[0042] E b = U b + I b (R T + jX T ) + U n (10)

[0043] E c = U c + I c (R T + jX T ) + U n (11)

[0044]

[0045] U n = I n (R n + jX n ) (13)

[0046] Among them, R n + jX n is the zero-sequence impedance of the three-phase transformer;

[0047] 3) R T and X T are calculated according to the following formula:

[0048]

[0049]

[0050]

[0051] Among them, U N is the rated voltage of the transformer, S N is the rated capacity of the transformer, P k is the short-circuit loss of the transformer, U k % is the percentage of the short-circuit voltage drop of the transformer, and k is the transformation ratio of the transformer;

[0052] 4) The method for estimating the zero-sequence impedance of a Yyn0-type transformer is as follows;

[0053] Select the historical normal data of the transformer for n days, and calculate E a 、E b 、E c using equations (6)-(8); According to the vector diagram, it can be obtained that:

[0054]

[0055] U n (re) = R n I n (re) - X n I n (im) (18)

[0056] U n (im) = R n I n (im) - X n I n (re) (19)

[0057] Adding equations (18)-(19), it can be obtained that:

[0058] U n (im) + U n (re) = R n (I n (re) + I n (im)) - X n (I n (im) + I n (re)) (20)

[0059] Regarding U n (im) + U n (re) as the dependent variable, and (I n (re) + I n (im) and -(I n (im) + I n (rm)) as the independent variables, there are 96n observation points in the historical normal data of the transformer for n days. Then, use the method of multiple linear regression to obtain Rn Value related to X n Value;

[0060] Step S42: Select the data of the metering points where the user has obvious electricity consumption behavior, and calculate the balance coefficient of the three-phase voltage on the high-voltage side, specifically:

[0061]

[0062] where m is the total number of metering points, and E ai , E bi , E ci are the three-phase voltages of phases A, B, and C of the i-th metering point respectively;

[0063] Step S43: Calculate the power factors of phases A, B, and C, specifically:

[0064]

[0065]

[0066]

[0067] Step S44: Obtain the balance situation P of the three-phase power factors of phases A, B, and C, specifically:

[0068]

[0069] where m is the total number of metering points, are the power factors of phases A, B, and C of the i-th metering point respectively;

[0070] Set a threshold ε; if ε c is greater than ε, it is determined that the three-phase power factors are unbalanced, and P is recorded as 0; if ε c is less than ε, it is determined that the three-phase power factors are balanced, and P is recorded as 1;

[0071] Step S45: According to the three-phase current values and their three-phase current phases corresponding to the 48 situations obtained, combined with the known three-phase voltage values and their three-phase voltage phases, repeat steps S41 - S44 to obtain the following three indicators for the 48 situations: the balance coefficient of the three-phase voltage on the high-voltage side; the power factors of phases A, B, and C; the balance situation of the three-phase power factors;

[0072] Step S46: Select several situations from the 48 situations calculated in step S45 where the power factors of phases A, B, and C are all positive for further determination.

[0073] Furthermore, step S5 specifically includes the following steps:

[0074] Step S51: Analyze the original wiring condition and the condition obtained in step S4 to determine whether there is abnormal wiring in the metering device and give the ideal wiring condition, as shown in the following table:

[0075]

[0076] In the above table, the balance coefficient of the three-phase voltage on the high-voltage side of the original wiring condition is M 1 , and the balance condition of the three-phase power factor is P 1 , and the power factors of phases A, B, and C are cos 1 , including The balance coefficient of the three-phase voltage on the high-voltage side of a certain case among several cases obtained in step S4 is M j , and the balance condition of the three-phase power factor is P j , and the power factors of phases A, B, and C are cos j , including

[0077] α represents the current wiring condition where the three-phase power factor cos j is the largest among several cases obtained in step S4 and the balance condition P of the three-phase power factor j is 1; β represents the original wiring condition.

[0078] Compared with the prior art, the present invention and its preferred solution propose a method for discriminating abnormal wiring of a metering device by combining the three-phase balance degree on the high-voltage side with empirical rules. It uses the exhaustive method to calculate some indexes of 48 possible current wiring situations of the metering device, including the balance coefficient of the three-phase voltage on the high-voltage side, the power factors of the three phases on the low-voltage side and their balance conditions, and determines whether there is abnormal wiring by analyzing the indexes. This method is only applicable to discriminating abnormal wiring of the metering device under the metering mode of high-voltage supply and low-voltage metering, and there are no current short-circuit and voltage phase-break faults in the metering device. Compared with the previous methods, it can reduce the probability of misjudgment and improve the accuracy of recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The present invention will be further described in detail below with reference to the drawings and specific embodiments:

[0080] Figure 1 is the overall flowchart of the embodiment of the present invention;

[0081] Figure 2 is the vector conversion relationship diagram of the high-voltage side and the low-voltage side voltages of the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0082] To make the features and advantages of this patent more obvious and understandable, specific embodiments are given below and described in detail as follows:

[0083] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0084] It should be noted that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0085] As Figure 1 shown below, the following are the specific steps for implementing the solution of the embodiment of the present invention:

[0086] Step 1: Obtain the three-phase voltage and three-phase current data measured by the metering device under the metering method of high supply and low metering in the 10 kV distribution network.

[0087] Step 2: There are mainly two types of connection groups for the three-phase transformers used in the 10 kV distribution network, namely Dyn11 type and Yyn0 type. For Yyn0 type transformers, their zero-sequence impedance is relatively large, and the influence of zero-sequence impedance needs to be considered; for Dyn11 type transformers, their zero-sequence impedance is relatively small, and the influence of zero-sequence impedance does not need to be considered. Therefore, this method needs to first determine the connection group of the transformer corresponding to the metering data, and then adopt different analysis ideas. The method for identifying the connection group of the distribution transformer and determining the connection group of the transformer corresponding to the data is as follows:

[0088] First, calculate the three-phase current unbalance degree ε i , specifically as follows:

[0089]

[0090] wherein, I A , I B , I C are the three-phase currents respectively;

[0091] Secondly, select the metering acquisition points with current unbalance degree greater than 10%, calculate their voltage unbalance degree and take the average value ε u , specifically as follows:

[0092]

[0093] In the above formula, U Ai , U Bi , U ciis the three-phase voltage value corresponding to the i-th metering and acquisition point with a current unbalance degree greater than 10%, and n is the number of metering and acquisition points with a current unbalance degree greater than 10%.

[0094] Finally, set a threshold through experience. If the average value of the voltage unbalance degree ε u is greater than this threshold, it is determined that the connection group of the transformer corresponding to this metering data is Yyn0 type, otherwise it is Dyn11 type.

[0095] Step 3: For AC sampling measurement, directly obtain the three-phase voltage phase and three-phase current phase of the AC sampling measurement from the system.

[0096] Step 4: For meter measurement, since it cannot collect phase information and can only obtain data such as three-phase voltage, three-phase current, three-phase active power, and three-phase reactive power, it is necessary to calculate the impedance angle to solve the three-phase voltage phase and three-phase current phase. If it is determined that the connection group of the transformer corresponding to the metering data is Dyn11 type, the three-phase voltage phase and three-phase current phase can be obtained through the following method:

[0097] For a Dyn11 type distribution transformer, there will be no neutral point shift phenomenon, and the three-phase voltages on the low-voltage side are relatively balanced. In this embodiment, it is defaulted that the three-phase voltage phase is normal. Therefore, let the three-phase voltage phases be α a 、α b 、α c , then α a =360、α b =240、α c =120.

[0098] Let the angles between the three-phase voltages and the three-phase currents be respectively The three-phase current phases are θ a 、θ b 、θ c , the collected three-phase active power values are P a 、P b 、P b , the collected three-phase reactive power Q a 、Q b 、Q c . The specific calculation formulas are as follows:

[0099]

[0100]

[0101] Step 5: Perform permutations and combinations of 48 current wiring methods according to Table 1 in the appendix to obtain the three-phase current values and their three-phase current phases corresponding to 48 situations. When performing permutations and combinations, reverse-phase current is required, and the data needs to be processed as follows:

[0102] It is known that the three-phase current phases are θ a 、θ b 、θ c , and it is necessary to perform an inverting process on the current phases to obtain three current phasors that are opposite to the current phasors measured by the device. At this time, there are a total of six current phases, denoted as θ1, θ2, θ3, θ4, θ5, and θ6. Among them, θ1, θ2, and θ3 are respectively equal to θ a 、θ b 、θ c , θ4 corresponds to θ1, θ5 corresponds to θ2, and θ6 corresponds to θ3. Thus, θ4, θ5, and θ6 can be obtained from θ1, θ2, and θ3 through Equation (5):

[0103]

[0104] Step 6: Use the relevant principles of the transformer to deduce the high-voltage side voltage of the transformer based on the measured values on the low-voltage side of the transformer. The calculation can be performed according to the vector conversion relationship between the high-voltage side and the low-voltage side voltage as shown in Figure 2 :

[0105] 1) If the connection group of the transformer corresponding to the metering data is Dyn11 type, the influence of zero-sequence impedance does not need to be considered, and the calculation formula represented by complex numbers is:

[0106] E a =U a +I a (R T +jX T ) (6)

[0107] E b =U b +I b (R T +jX T ) (7)

[0108] E c =U c +I c (R T +jX T ) (8)

[0109] In the above formula, E a 、E b 、E c are the secondary-side reduced values of the three-phase voltages on the high-voltage side of the transformer, R T is the secondary-side reduced value of the equivalent resistance of the transformer, and X T is the secondary-side reduced value of the equivalent reactance of the transformer.

[0110] 2) If the connection group of the transformer corresponding to the metering data is Yyn0, the influence of the zero-sequence impedance needs to be considered, and the calculation formula represented by complex numbers is:

[0111] E a = U a + I a (R T + jX T ) + U n (9)

[0112] E b = U b + I b (R T + jX T ) + U n (10)

[0113] E c = U c + I c (R T + jX T ) + U n (11)

[0114]

[0115] U n = I n (R n + jX n ) (13)

[0116] Among them, R n + jX n is the zero-sequence impedance of the three-phase transformer

[0117] 3) R T and X T can be calculated according to the following formula:

[0118]

[0119]

[0120]

[0121] Among them, U N is the rated voltage of the transformer, S N is the rated capacity of the transformer, P k is the short-circuit loss of the transformer, U k % is the percentage of the short-circuit voltage drop of the transformer, and k is the transformation ratio of the transformer.

[0122] 4) The estimation method of the zero-sequence impedance of the Yyn0 transformer is as follows;

[0123] Select the historical normal data of the transformer for n days, and calculate E using equations (6)-(8). a and E b and E c . According to the vector diagram, it can be obtained that:

[0124]

[0125] U n (re) = R n I n (re) - X n I n (im) (18)

[0126] U n (im) = R n I n (im) - X n I n (re) (19)

[0127] Adding equations (18)-(19), it can be obtained that:

[0128] U n (im) + U n (re) = R n (I n (re) + I n (im)) - X n (I n (im) + I n (re)) (20)

[0129] Regarding U n (im) + U n (re) as the dependent variable, and (I n (re) + I n (im) and -(I n (im) + I n (rm)) as the independent variables. There are 96n observation points in the historical normal data of the transformer for n days. The values of R n and X n can be obtained by means of multiple linear regression.

[0130] Step 7: Select the data of the metering points where the user has obvious electricity consumption behavior, and calculate the balance coefficient of the three-phase voltage on the high-voltage side, specifically:

[0131]

[0132] where m is the total number of metering points, and E ai and E bi and E ciThey are the voltages of phases A, B, and C at the i-th metering point respectively.

[0133] Step 8: Calculate the power factors of phases A, B, and C, specifically as follows:

[0134]

[0135]

[0136]

[0137] Step 9: Obtain the balance condition P of the three-phase power factors of phases A, B, and C, specifically as follows:

[0138]

[0139] where m is the total number of metering points, They are the power factors of phases A, B, and C at the i-th metering point respectively.

[0140] Set a certain threshold ε (such as 0.2). If ε c is greater than ε, it is judged that the three-phase power factors are unbalanced, and P is recorded as 0; if ε c is less than ε, it is judged that the three-phase power factors are balanced, and P is recorded as 1.

[0141] Step 10: According to the three-phase current values and their three-phase current phases corresponding to the 48 cases obtained, combined with the known three-phase voltage values and their three-phase voltage phases, repeat Steps 6-9 to obtain the following three indicators for the 48 cases: ① The balance coefficient of the high-voltage side three-phase voltages. ② The power factors of phases A, B, and C. ③ The balance condition of the three-phase power factors.

[0142] Step 11: Select several cases where the power factors of phases A, B, and C are all positive from the 48 cases calculated in Step 10 for further determination. For example, if are all greater than 0, the 10th current wiring condition meets the requirements and can be used for further determination.

[0143] Step 12: Analyze the original wiring condition and the several cases obtained in Step 11 to judge whether there is an abnormal wiring in the metering device and give the ideal wiring condition, as shown in the following table:

[0144]

[0145] In the above table, the balance coefficient of the high-voltage side three-phase voltages of the original wiring condition is M 1 , the balance condition of the three-phase power factors is P 1 , and the power factors of phases A, B, and C are cos 1 , including The balance coefficient of the three-phase voltage on the high-voltage side in one of the several situations obtained in step 11 is M j , and the balance situation of the three-phase power factor is P j , and the power factors of phases A, B, and C are cos j , including

[0146] Regarding the ideal wiring situations in the above table: α represents the current wiring situation in which the three-phase power factor cos j is the largest and the balance situation P of the three-phase power factor j is 1; β represents the original wiring situation.

[0147] Regarding the wiring situations in the above table: Suspected abnormality means that there is a certain possibility that the metering device is abnormal; Highly likely abnormality means that there is a great possibility that the metering device is abnormal.

[0148] If the wiring situation is determined to be abnormal or highly likely abnormal, it is recommended to go to the site to check whether there is indeed a wiring error; if the wiring situation is determined to be suspected of abnormality, it may be necessary to go to the site to check whether there is indeed a wiring error according to the situation. The ideal wiring situation can assist in the on-site judgment, but it is necessary to first judge whether there is an abnormal wiring in the voltage circuit.

[0149] Appendix 1

[0150]

[0151]

[0152] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0153] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for implementing in the processFigure 1 one or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks

[0154] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction means that implements the functions in the process Figure 1 one or more processes and / or blocks Figure 1 specified in one or more blocks

[0155] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the functions specified in the process Figure 1 one or more processes and / or blocks Figure 1 steps for the functions specified in one or more blocks

[0156] As described above, it is only the preferred embodiment of the present invention, and it is not a limitation to the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention

[0157] This patent is not limited to the above best mode. Anyone can obtain other various forms of methods for discriminating abnormal wiring of high supply and low metering devices under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention shall fall within the coverage of this patent

Claims

1. A discrimination method for abnormal wiring of a high-voltage supply and low-voltage metering device, characterized in that, It includes the following steps: Step S1: Obtain the three-phase voltage and three-phase current data measured by the metering device under the metering method of high supply and low metering in the 10KV distribution network; Step S2: Identify the connection group of the distribution transformer to determine the connection group of the transformer corresponding to the data; Step S3: Obtain the three-phase voltage phase and three-phase current phase; Step S4: Use the exhaustive method to arrange and combine 48 possible current connection situations, and calculate the balance coefficient of the high-voltage side three-phase voltage, the power factors of phases A, B, and C, and the balance situation of the three-phase power factors for each situation. Select one or more situations where the power factors of phases A, B, and C are all positive from the 48 situations for the next discrimination; Step S5: According to the wiring situation and the results obtained in Step S4, use the judgment rules to determine whether there is an abnormal wiring in the power monitoring device; Step S4 specifically includes the following steps: Step S41: Use the relevant principles of the transformer to deduce the high-voltage side voltage of the transformer from the measured values on the low-voltage side of the transformer: 1) If the connection group of the transformer corresponding to the metering data is Dyn11 type, the influence of the zero-sequence impedance does not need to be considered, and the calculation formula represented by complex numbers is: E a = U a + I a (R T + jX T ) (6) E b = U b + I b (R T + jX T ) (7) E c = U c + I c (R T + jX T ) (8) In the above formula, E a , E b , E c are the reduced values on the secondary side of the three-phase voltages on the high-voltage side of the transformer, R T is the reduced value of the equivalent resistance of the transformer on the secondary side, and X T is the reduced value of the equivalent reactance of the transformer on the secondary side; 2) If the connection group of the transformer corresponding to the metering data is Yyn0 type, the influence of the zero-sequence impedance needs to be considered, and the calculation formula represented by complex numbers is: E a = U a + I a (R T + jX T ) + U n (9) E b = U b + I b (R T + jX T ) + U n (10) E c = U c + I c (R T + jX T ) + U n (11) U n = I n (R n + jX n )(13) wherein, R n +jX n is the zero-sequence impedance of the three-phase transformer; 3)R T with X T Calculate according to the following formula: Among them, U N is the rated voltage of the transformer, S N is the rated capacity of the transformer, P k is the short-circuit loss of the transformer, U k % is the percentage of the short-circuit voltage drop of the transformer, and k is the transformation ratio of the transformer; 4) The estimation method of the zero-sequence impedance of the Yyn0 type transformer is as follows; Select the historical normal data of the transformer for n days, and calculate E using equations (6)-(8). a , E b , E c ; According to the vector diagram, it can be obtained that: U n (re) = R n I n (re) - X n I n (im) (18) U n (im) = R n I n (im) - X n I n (re) (19) Adding equations (18)-(19) gives: U n (im)+U n (re)=R n (I n (re)+I n (im))-X n (I n (im)+I n (re)) (20) Take U n (im) + U n as the dependent variable, (I n (re) + I n (im) and -(I n (im) + I n (rm)) as the independent variables. There are 96n observation points in the n-day historical normal data of the transformer. Then, use the method of multiple linear regression to obtain the values of R n and X n ; Step S42: Select the data of the metering point where the user has obvious electricity consumption behavior, and calculate the balance coefficient of the high-voltage side three-phase voltage, specifically: where m is the total number of metering points, and E ai , E bi , and E ci are the three-phase voltages of phases A, B, and C at the i-th metering point, respectively; Step S43: Calculate the power factors of phases A, B, and C, specifically: Among them, the three-phase voltage phase is α a and α b and α c , and the angles between the three-phase voltage and the three-phase current are respectively The three-phase current phase is θ a and θ b and θ c ; Step S44: Obtain the balance situation P of the three-phase power factors of phases A, B, and C, specifically: where m is the total number of metering points, are the power factors of phases A, B, and C at the i-th metering point, respectively; Set a threshold ε; if ε c is greater than ε, it is determined that the three-phase power factor is unbalanced, and P is recorded as 0; if ε c is less than ε, it is determined that the three-phase power factor is balanced, and P is recorded as 1; Step S45: According to the three-phase current values and their three-phase current phases corresponding to the 48 situations obtained, combined with the known three-phase voltage values and their three-phase voltage phases, repeat Steps S41 - S44 to obtain the following three indicators for the 48 situations: the balance coefficient of the high-voltage side three-phase voltage; the power factors of phases A, B, and C; the balance situation of the three-phase power factors; Step S46: Select several situations where the power factors of phases A, B, and C are all positive from the 48 situations calculated in Step S45 for further determination.

2. The discriminant method for abnormal wiring of high-voltage supply and low-voltage metering devices according to claim 1, characterized in that: Step S2 specifically includes the following steps: Step S21: Calculate the three-phase current unbalance degree ε of the metering data i , specifically as follows: Among them, I a , I b , I c are the three-phase currents respectively; Step S22: Select the metering and acquisition points with current unbalance greater than 10%, calculate their voltage unbalance and take the average value ε u , specifically: In the above formula, U ai , U bi , U ci are the three-phase voltage values corresponding to the i-th metering and acquisition point with a current unbalance degree greater than 10%, and n is the number of metering and acquisition points with a current unbalance degree greater than 10%; Step S23: Set a threshold value through experience. If the average value ε of the voltage unbalance degree u is greater than this threshold value, it is determined that the connection group of the transformer corresponding to this metering data is Yyn0 type; otherwise, it is Dyn11 type.

3. The abnormal wiring discrimination method for high-voltage supply and low-voltage metering devices according to claim 1, characterized in that: In Step S3, under the condition of meter measurement, calculate and solve the three-phase voltage phase and three-phase current phase through the impedance angle.

4. According to the method for discriminating abnormal wiring of the high supply and low metering device described in claim 3, it is characterized in that: For AC sampling measurement, if it is determined that the connection group of the transformer corresponding to the metering data is Dyn11 type, the three-phase voltage phase and three-phase current phase are obtained through the following method: On the premise that the default three-phase voltage phase is normal, let the three-phase voltage phase be α a , α b , α c , then α a = 360, α b = 240, α c = 120; Let the angles between the three-phase voltages and the three-phase currents be respectively The phase of the three-phase current is θ a 、θ b 、θ c , and the collected three-phase active power values are P a 、P b 、P c , and the collected three-phase reactive power Q a 、Q b 、Q c ; The calculation formulas are as follows:

5. The abnormal wiring discrimination method for high supply and low metering devices according to claim 1, characterized in that: When arranging and combining the 48 situations in Step S4, reverse-phase current is required, and the data is processed as follows: It is known that the phases of three-phase currents are θ a , θ b , θ c . It is necessary to perform an inverting process on the phases of the currents to obtain three current phasors that are opposite to the current phasors measured by the device. At this time, there are a total of six current phases, denoted as θ1, θ2, θ3, θ4, θ5, θ6; among them, θ1, θ2, θ3 are respectively equal to θ a , θ b , θ c , θ4 corresponds to θ1, θ5 corresponds to θ2, and θ6 corresponds to θ3; among them, θ4, θ5, θ6 are obtained from θ1, θ2, θ3 by Equation (5):

6. The abnormal wiring discrimination method for high-voltage supply and low-voltage metering device according to claim 1, wherein: Step S5 specifically includes the following steps: Step S51: Analyze the original wiring situation and the situation obtained in Step S4 to determine whether there is an abnormal wiring in the metering device and give the ideal wiring situation: Type ①: Three-phase power factor balance: Not specified Balance coefficient of three-phase voltage on the high-voltage side: Not specified Power factors of three phases A, B, and C: and and Wiring condition: Abnormal Ideal wiring condition: α Type ②: Three-phase power factor balance condition: P 1 = 0 Balance coefficient of three-phase voltage on the high-voltage side: Not specified Power factors of phases A, B, and C: Not specified Wiring condition: Abnormal Ideal wiring condition: α Type ③: Three-phase power factor balance: P 1 = P j = 1 Relationship between balance coefficient of three-phase voltage and power factor on the high-voltage side: If M 1 <M j : When cos 1 > cos j , the wiring condition is "normal", and the ideal wiring condition is β; When cos 1 <cos j When it is the case, the wiring condition is "suspected abnormality", and there is no specified ideal wiring condition. If M 1 >M j : When cos 1 > cos j the wiring condition is "suspected abnormal", and there is no specified ideal wiring condition; When cos 1 <cos j When it is the case, the wiring condition is "most likely abnormal", and the ideal wiring condition is α; Among them, the balance coefficient of the three-phase voltage on the high-voltage side of the original wiring condition is M 1 , the balance condition of the three-phase power factor is P 1 , the power factors of phases A, B, and C are cos 1 , which includes the balance coefficient of the three-phase voltage on the high-voltage side of a certain case among several cases obtained in step S4 is M j , the balance condition of the three-phase power factor is P j , the power factors of phases A, B, and C are cos j , which includes α represents the three-phase power factor cos in several cases obtained in step S4 j with the largest value and the balanced condition P of the three-phase power factor j for the current connection condition where it is 1; β represents the original connection condition.

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