Three-phase four-wire direct access type intelligent electric energy meter electricity stealing quantity auxiliary calculation method

Abstract

The invention discloses a three-phase four-wire direct access type intelligent electric energy meter electricity stealing quantity auxiliary calculation method, aiming at a voltage loss electricity stealing type, the voltage of a voltage loss phase is reduced through phasor synthesis calculation, and the voltage loss electricity stealing type comprises a condition that a one-phase voltage connection sheet is opened or loosened and a condition that a two-phase voltage connection sheet is opened or loosened. For the electricity stealing type of privately connecting one live wire, electricity stealing current is synthesized through phasor calculation, and the electricity stealing type of privately connecting one live wire shows that A, B and C three-phase current phasors in the electric energy meter are not consistent with zero-sequence current after being synthesized; according to the method, the most common electricity stealing mode of opening or loosening a voltage connecting sheet to steal electricity in a three-phase four-wire direct access type electric energy meter without voltage is effectively identified; according to the algorithm disclosed by the invention, the electricity stealing quantity is calculated, the electricity stealing quantity affirmation accuracy and normative degree are greatly improved, and affirmation disputes can be reduced.

Description

Technical Field

[0001] The invention relates to an auxiliary calculation method for electric quantity theft, and in particular to an auxiliary calculation method for electric quantity theft of a three-phase four-wire direct access type intelligent electric energy meter. Background Art

[0002] The three-phase four-wire direct access smart energy meter belongs to the Class IV electric energy metering device specified in the "Technical Management Regulations for Electric Energy Metering Devices" (DL / T 448-2016). It is generally used in low-voltage three-phase four-wire circuits. The voltage specification is 3×220 / 380V, and the maximum current generally does not exceed 100A. The standard current specifications of the State Grid Corporation are 3×5 (60) A and 3×10 (100) A. At present, the three-phase four-wire direct access smart energy meter is based on the principle of digital sampling. It can realize phase sampling of the voltage, current, phase angle and other power parameters of the three phases A, B and C, and calculate and count the power consumption data by calculating the sampled data.

[0003] The new version of the "Electricity Supply Business Rules" was officially implemented on June 1, 2024. Article 105 revised the provisions of Article 103 of the 1996 version of the "Electricity Supply Business Rules". It no longer directly specifies the calculation method, but is revised to "If it can be verified that the user has stolen electricity, the amount of stolen electricity shall be determined according to the verified amount." If the amount of stolen electricity cannot be verified, it shall be calculated according to the specified method. The vast majority of existing schemes are based on the old version of the 1996 version of the "Electricity Supply Business Rules" for verification.

[0004] There is a rare example of an anti-electricity theft smart meter and an electricity theft detection and metering method with publication number CN116520018A, which specifically discloses a control chip, a metering chip, a main loop current sampling unit, a secondary loop current sampling unit, a voltage sampling unit and a main loop current sensing element. The main loop current sampling unit samples the main loop current to obtain the main loop electrical parameters; the secondary loop current sampling unit samples the secondary loop current to obtain the secondary loop electrical parameters; the voltage sampling unit performs voltage division sampling on the AC voltage to obtain the voltage electrical parameters; the metering chip measures the electric energy based on the above parameters to obtain the metering result; the control chip determines whether zero power theft occurs based on the metering result, and if zero power theft occurs, the main loop current sensing element is controlled to work; the main loop current sensing element measures the current value of the main loop; the control chip multiplies the current value by the rated voltage to obtain the current power. Although the application discloses a method for detecting electricity theft in existing smart meters, it has strong limitations in use. It only discloses risk detection for electricity theft due to zero-circuit conditions and covers few types of applications. Moreover, the calculation method of the application is to measure the electrical energy using conventional main circuit electrical parameters, secondary circuit electrical parameters and voltage electrical parameters to obtain the measurement results. It has not disclosed any derivation formula that can guarantee accurate calculations, and cannot meet the requirements of the new regulations.

[0005] In order to adapt to the new requirements of the new regulations to restore the actual electricity loss as much as possible, power supply companies should adopt effective technical means to fairly and impartially determine the amount of electricity theft and fully guarantee the legitimate rights and interests of both electricity suppliers and users. Summary of the invention

[0006] In order to solve the deficiencies of the above-mentioned technologies, the present invention provides an auxiliary calculation method for the amount of electricity stolen from a three-phase four-wire direct-access smart energy meter.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: an auxiliary calculation method for the amount of electricity theft in a three-phase four-wire direct-access smart electricity meter. For the type of electricity theft caused by voltage loss, the voltage of the voltage-loss phase is restored through phase synthesis calculation. The voltage-loss electricity theft type includes the situation where one-phase voltage connecting piece is opened or loose and the situation where two-phase voltage connecting pieces are opened or loose.

[0008] If one-phase voltage connector is opened or loose, that is, the voltage of any phase among the three phases A, B, and C is lower than 150V, the voltage of the lost phase will be restored by synthesizing the normal voltages of the remaining two phases; if two-phase voltage connector is opened or loose, that is, the voltage of any two phases among the three phases A, B, and C is lower than 150V, the voltage of the lost two phases will be restored by shifting the normal voltage of the remaining phase.

[0009] For those who steal electricity by unauthorizedly connecting to a live wire, the stolen current is synthesized through phasor calculation. The stolen electricity by unauthorizedly connecting to a live wire is manifested as the phase synthesis of the A, B, and C phase currents in the electricity meter not matching the zero-sequence current.

[0010] Furthermore, when a phase voltage connection piece is opened or loosened, the phase synthesis calculation formula is: , In the formula, is the voltage of the voltage-losing phase; , The remaining two phases are in normal voltage.

[0011] Furthermore, the actual amount of electricity generated by the phase is calculated based on the voltage of the phase after phase synthesis and restoration and the current of the phase measured by the electric energy meter. The calculation formula is: , In the formula, The actual amount of electricity generated in the pressure-loss phase; It is the voltage-loss phase current measured by the electric energy meter; for and The phase angle of .

[0012] Furthermore, the calculation formula for the amount of electricity stolen when a phase voltage connection piece is opened or loose is: , Where: To steal electricity; The electricity meter has measured the electricity in the phase where the voltage has been lost.

[0013] Furthermore, when the two-phase voltage connecting piece is opened or loose, the normal voltage phase of the remaining phase is rotated 120° clockwise and counterclockwise to simulate the voltage loss of the two phases. The phase shift calculation formula is as follows: , , Where: , is the voltage of the two phases without voltage; The remaining phase voltage is normal.

[0014] Furthermore, the actual amount of electricity generated by the phase is calculated based on the restored voltage of the depressurized phase and the current of the phase measured by the electric energy meter. The calculation formula is: , Where: , They are the actual amount of electricity generated in the two phases under voltage loss; , They are respectively the voltage-loss two-phase currents measured by the electric energy meter; for and The phase angle of for and The phase angle of .

[0015] Furthermore, the calculation formula for the amount of electricity stolen when the two-phase voltage connection piece is opened or loose is: , Where: To steal electricity; , They are the measured electricity quantities in the two phases when the electric energy meter loses voltage.

[0016] Furthermore, the phasor synthesis calculation formula for privately connecting a live wire to steal electricity is as follows: , Where: It is the electricity stealing current; , , They are the three-phase currents measured by the electric energy meter; It is the zero-sequence current measured by the electric energy meter.

[0017] Furthermore, the amount of electricity theft is calculated based on the obtained electricity theft current and the phase voltage with the smallest absolute value of the phase angle with the electricity theft current. The calculation formula is: , Where: To steal electricity; The stealing current The phase voltage with the smallest absolute value of the phase angle; for and The phase angle of .

[0018] Furthermore, the electric energy meter used for calculating theft of electricity by privately connecting a live wire must have a zero-sequence current measurement function.

[0019] The present invention discloses an auxiliary calculation method for the amount of electricity theft in a three-phase four-wire direct-access smart energy meter, which effectively identifies the most common electricity theft method of opening or loosening a voltage connection piece to cause voltage loss and electricity theft in a three-phase four-wire direct-access energy meter; the algorithm disclosed in the present application calculates the amount of electricity theft, greatly improving the accuracy and standardization of the identification of the amount of electricity theft, which is conducive to reducing identification disputes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the measurement principle diagram of a three-phase four-wire direct access smart energy meter.

[0021] Figure 2 The diagram is a phase synthesis calculation process diagram when a phase voltage connection piece is opened or loose.

[0022] Figure 3 The diagram shows the phase movement process when the two-phase voltage connection piece is opened or loosened.

[0023] Figure 4 The diagram shows the phase synthesis calculation process for privately connecting a live wire to steal electricity.

[0024] Figure 5 These are the phasors of various physical quantities recorded by the electric energy meter in the electricity theft state of Example 1.

[0025] Figure 6 This is the phasor diagram of the C phase voltage after restoration in Example 1.

[0026] Figure 7 These are the phasors of various physical quantities recorded by the electric energy meter in the electricity theft state of Example 2.

[0027] Figure 8 This is the phasor diagram of the B and C phase voltages after restoration in Example 2.

[0028] Fig. 9 These are the phasors of various physical quantities recorded by the electric energy meter in the electricity theft state of Example 3.

[0029] Fig.10 This is the electricity theft current phasor calculation diagram of Example 3. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0031] This implementation is about the auxiliary calculation method of the stolen electricity quantity of the three-phase four-wire direct access smart energy meter, such as Figure 1 As shown, it is a metering principle diagram of a three-phase four-wire direct-access smart energy meter used in this embodiment, which has a total of eight external wiring terminals, namely, an A-phase metering unit, a B-phase metering unit, a C-phase metering unit, and a zero-sequence current measuring unit, and the number of each of the four is two; wherein, the A-phase metering unit is connected to the A-phase on the power supply side and the A-phase on the load side from left to right, respectively, and samples the current in the A-phase circuit and the voltage between the A-phase and the neutral line, and then calculates the amount of electricity according to the value and phase; the B-phase metering unit is connected to the B-phase on the power supply side and the B-phase on the load side from left to right, respectively, and samples the current in the B-phase circuit and the voltage between the B-phase and the neutral line, and then calculates the amount of electricity according to the value and phase; the C-phase metering unit is connected to the C-phase on the power supply side and the C-phase on the load side from left to right, respectively, and samples the current in the C-phase circuit and the voltage between the C-phase and the neutral line, and then calculates the amount of electricity according to the value and phase; the zero-sequence current measuring unit is connected to the N-phase on the power supply side and the N-phase on the load side from left to right, respectively, and samples the current in the N-phase circuit, and then calculates the amount of electricity according to the value and phase.

[0032] The calculation method disclosed in this implementation targets two types of electricity theft, one is theft by loss of voltage, and the other is theft by privately connecting a live wire. It should be noted that theft by loss of voltage is achieved by opening or loosening the voltage connector of the energy meter, causing the voltage value of the changed phase measured by the energy meter to be too low or the phase to shift, resulting in the energy meter under-measuring electricity. Theft by privately connecting a live wire is achieved by privately connecting a live wire for electricity use, bypassing the energy meter, and not being measured by the energy meter.

[0033] For the type of power theft caused by voltage loss, this embodiment restores the voltage of the voltage-loss phase through phasor synthesis calculation. The type of power theft caused by voltage loss includes the situation that one-phase voltage connecting piece is opened or loose and the situation that two-phase voltage connecting pieces are opened or loose. Among them, in the situation that one-phase voltage connecting piece is opened or loose, that is, the voltage of any one of the three phases A, B, and C is lower than 150V, the voltage of the voltage-loss phase is restored by synthesizing the normal voltages of the remaining two phases; in the situation that the two-phase voltage connecting piece is opened or loose, that is, the voltage of any two of the three phases A, B, and C is lower than 150V, the voltage of the voltage-loss two phases is restored by phase shifting the normal voltage of the remaining phase.

[0034] For those who steal electricity by unauthorizedly connecting to a live wire, the stolen current is synthesized through phasor calculation. The stolen electricity by unauthorizedly connecting to a live wire is manifested as the phase synthesis of the A, B, and C phase currents in the electricity meter not matching the zero-sequence current.

[0035] Example 1 When one phase voltage connection piece is opened or loose, causing abnormal voltage of one phase, the normal voltage phase quantities of the other two phases can be synthesized, and then the synthesized phase quantities are inverted to approximately obtain the actual voltage value and phase of the abnormal phase. According to the metering principle, the product of this voltage value, the current value of this phase measured by the electric energy meter, and the cosine value of the angle between this voltage and the current of this phase measured by the electric energy meter (that is, the power factor) is integrated over time to obtain the actual amount of electricity generated in the abnormal phase. This amount of electricity minus the amount of electricity already measured by the electric energy meter for this phase is the difference in electricity, that is, the amount of stolen electricity.

[0036] Preferably, according to the above principle, when a phase voltage connecting piece is opened or loosened, the phase synthesis calculation process diagram is as follows: Figure 2 As shown, specifically: The phase synthesis calculation formula is: Where, is the voltage of the phase without voltage; and are the normal voltages of the other two phases; Then, the actual amount of electricity generated in the phase is calculated based on the restored voltage of the depressurized phase and the current of the phase measured by the electric energy meter. The calculation formula is: Where: is the actual amount of electricity generated in the voltage-losing phase; is the voltage-losing phase current measured by the electric energy meter; is the phase angle of and; The calculation formula for the amount of electricity stolen is: In the formula: is the amount of stolen electricity; is the amount of electricity measured in the voltage-losing phase of the electricity meter.

[0037] The specific typical implementation of this embodiment is as follows: when the electric energy meter installed at the electricity theft user is a low-voltage three-phase four-wire direct-access smart electric energy meter, the electricity theft is carried out by opening the C-phase voltage connection piece of the electric energy meter, causing the C-phase metering voltage value of the electric energy meter to be 0V, and it cannot be correctly measured. After the electricity theft occurs, the power load data recorded in the electric energy meter is shown in the following Table 1-1.

[0038] Table 1-1 Load data recorded by the electric energy meter in the state of electricity theft:

[0039] The phase relationship between the physical quantities is measured by the electric energy meter as shown in the attached Figure 5 shown.

[0040] In this embodiment, the C phase voltage is restored based on the above calculation formula, and the specific calculation is as follows: Where: , They are the voltages of phase A and phase B respectively; is the voltage after phase C is restored.

[0041] Furthermore, after reduction, the phase quantities are as follows Figure 6After reduction, the C phase metering unit should measure the value as shown in Table 1-2.

[0042] Table 1-2 Actual load data of the circuit after restoration:

[0043] It can be understood that this embodiment assumes that its three-phase power load is constant, that is, the current value and power factor in Table 1-1 above are constant. In practice, the load generally fluctuates. The smart energy meter can perform real-time integration operations on the sampled data, and thus it can be understood that this example is an integral slice at a certain moment under actual working conditions.

[0044] Next, assuming that the electricity theft has occurred for 300 hours, the amount of electricity stolen is calculated as: Where: is the actual amount of electricity generated by phase C; is the C phase current measured by the electric energy meter; for and The phase angle of Where: To steal electricity; The measured electricity quantity of phase C of the energy meter.

[0045] Example 2 When the two-phase voltage connection piece is opened or loose, causing the two-phase voltage to be abnormal, according to the principle that the voltage in the actual three-phase circuit is generally approximately balanced, the normal voltage phasor of the remaining one phase is rotated 120° clockwise and 120° counterclockwise respectively, and the actual voltage value and phase of the abnormal two phases are simulated. It should be noted that the actual power load on site is generally an inductive load. Therefore, the current phasor that lags behind this voltage in phase and has the smallest angle with this voltage can be determined as the current in phase with the voltage. According to the measurement principle, the product of the two-phase voltage value, the in-phase current value measured by the electric energy meter, and the cosine value of the angle between the two-phase voltage and the in-phase current measured by the electric energy meter (that is, the power factor) is integrated over time to obtain the actual amount of electricity generated in the abnormal two phases. This amount of electricity is subtracted from the amount of electricity measured by the electric energy meter for that phase, which is the difference in electricity, that is, the amount of electricity stolen.

[0046] Preferably, according to the above principle, when the two-phase voltage connecting piece is opened or loosened, the phase movement process is as follows: Figure 3 As shown, specifically: The phase shift calculation formula is as follows: Where: , are the voltages of the two phases without voltage; is the normal voltage of the remaining phase; Then, the actual amount of electricity generated in the phase is calculated based on the restored voltage of the depressurized phase and the current of the phase measured by the electric energy meter. The calculation formula is: Where: , are the actual electric quantities generated in the two phases under voltage respectively; , are the two phase currents under voltage measured by the electric energy meter respectively; is the phase angle of and ; is the phase angle of and ; The calculation formula for the amount of electricity stolen is: In the formula: is the amount of stolen electricity; and are the measured amounts of electricity in the two phases when the electricity meter loses voltage.

[0047] The specific typical implementation of this embodiment is: when the electric energy meter installed at the electricity theft user is a low-voltage three-phase four-wire direct-access smart electric energy meter, the electricity theft is carried out by opening the B and C phase voltage connection plates of the electric energy meter, causing the B and C phase measurement voltage values ​​of the electric energy meter to be 0V, and it cannot be measured correctly. After the electricity theft occurs, the power load data recorded in the electric energy meter is shown in the following Table 2-1: Table 2-1 Load data recorded by the electric energy meter in the state of electricity theft:

[0048] The phase relationship between the physical quantities is measured by the electric energy meter as shown in the attached Figure 7 Based on the calculation formula shown in this embodiment, the voltages of phases B and C are restored, and the specific calculation is: Where: , are the voltages of phase B and phase C after restoration; is the A phase voltage.

[0049] After reduction, the quantities of each phase are as shown in the attached Figure 8 As shown, after reduction, the metering values ​​of B and C phases should be as shown in Table 2-2.

[0050] Table 2-2 Actual load data of the circuit after restoration:

[0051] It can be understood that this embodiment assumes that the three-phase power load is constant, that is, the current value and power factor in Table 2-1 above are constant. In practice, the load generally fluctuates. The smart energy meter can perform real-time integration operations on the sampled data. This example can be understood as an integral slice at a certain moment under actual working conditions.

[0052] Assuming that the electricity theft has occurred for 300 hours, the amount of electricity stolen is calculated as: Where: , They are the actual electricity generated by phases B and C respectively; , They are the B and C phase currents measured by the electric energy meter respectively; for and The phase angle of for and The phase angle of .

[0053] Where: To steal electricity; , They are the measured electricity of phases B and C of the energy meter respectively.

[0054] Example 3 When there is a situation of stealing electricity by privately connecting a live wire, it is generally manifested as the three-phase current phase synthesis being inconsistent with the zero-sequence current. This is usually caused by currents from other circuits mixed into the circuit. It can be preliminarily determined that there is suspected electricity theft by privately connecting a live wire. In actual operation, electricity is usually measured by privately connecting a live wire to bypass the electric energy meter, but the neutral wire uses the neutral wire connected to the electric energy meter. At this time, according to the current phasor relationship, the three-phase currents A, B, and C measured by the electric energy meter are synthesized, and the zero-sequence current phasor measured by the zero-sequence current measurement unit of the electric energy meter is subtracted from the synthesized phasor of the three-phase currents A, B, and C to obtain the electric power theft current phasor. Because the actual power load on site is generally an inductive load, the voltage that is ahead of the electric power theft current phasor in phase and has the smallest angle with the electric power theft current phasor can be determined as the voltage in phase with the electric power theft current. According to the metering principle, the product of this voltage value, the synthetically calculated electric power theft current value, and the cosine value of the angle between this voltage and the synthetically calculated electric power theft current (that is, the power factor) is integrated over time to obtain the actual amount of electricity generated on the private wiring, that is, the amount of electricity generated by bypassing the power consumption part of the electric energy meter, that is, the amount of theft.

[0055] Preferably, according to the above principle, the phasor synthesis calculation process of privately connecting a live wire to steal electricity is as shown in the figure below: Figure 4 As shown, specifically: The phase synthesis calculation formula is: In the formula: is the electricity theft current; , , are the three-phase currents measured by the electric energy meter; is the zero-sequence current measured by the electric energy meter.

[0056] Then, the stolen electricity amount is calculated based on the obtained stolen electricity current and the phase voltage with the smallest absolute value of the phase angle with the stolen electricity current. The calculation formula is: In the formula: is the amount of electricity stolen; is the phase voltage with the smallest absolute value of the phase angle with the electricity theft current; is the phase angle of and.

[0057] The specific typical implementation of this embodiment is: when the electric energy meter installed at the electricity theft user is a low-voltage three-phase four-wire direct-access smart electric energy meter (with zero-sequence current measurement function), the user steals electricity by privately connecting a live wire, which is not measured by the electric energy meter and is considered as the electricity theft part. After the electricity theft occurs, the power load data recorded in the electric energy meter is shown in the following Table 3-1.

[0058] Table 3-1 Load data recorded by the electric energy meter in the state of electricity theft:

[0059] The phase relationship between the physical quantities is measured by the electric energy meter as shown in the attached Fig. 9 As shown, it can be seen According to the calculation formula shown in this embodiment, the electricity stealing current is calculated as follows: Where: It is the electricity stealing current; , , They are the three-phase currents measured by the electric energy meter; It is the zero-sequence current measured by the electric energy meter.

[0060] According to the above method, the phasor calculation process is shown in the attached figure. Fig.10 As shown, after the phase calculation, the power theft current The voltage with the smallest angle is ,Right now , then the power theft circuit load data is shown in Table 3-2.

[0061] Table 3-2 Power theft circuit load data:

[0062] It can be understood that this embodiment assumes that the three-phase power load is constant, that is, the current value and power factor in Table 3-1 above are constant. In practice, the load generally fluctuates. The smart energy meter can perform instant integration operations on the sampled data. This example can be understood as an integral slice at a certain moment under actual working conditions.

[0063] Assuming that the electricity theft has occurred for 300 hours, the amount of electricity stolen is calculated as: Where: is the amount of electricity stolen; is the phase voltage with the smallest absolute value of the phase angle with the electricity theft current; is the phase angle of and; The duration of electricity theft.

[0064] The present embodiment discloses a method for auxiliary calculation of the amount of electricity theft in a three-phase four-wire direct-access smart energy meter, which effectively identifies the most common theft method of electricity theft in a three-phase four-wire direct-access energy meter, which is the loss of voltage due to opening or loosening the voltage connection piece. The algorithm disclosed in the present application calculates the amount of electricity theft, which greatly improves the accuracy and standardization of the identification of the amount of electricity theft, and is conducive to reducing identification disputes.

[0065] The above implementation modes are not limitations of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also belong to the protection scope of the present invention.

Claims

1. A method for auxiliary calculation of electric quantity theft of a three-phase four-wire direct access smart electric energy meter, characterized in that: For the voltage loss and electricity theft, the voltage of the voltage loss phase is restored by phasor synthesis calculation. The voltage loss and electricity theft includes the situation where one phase voltage connection piece is opened or loose and the situation where two phase voltage connection pieces are opened or loose. If the one-phase voltage connection piece is opened or loosened, that is, the voltage of any one of the three phases A, B, and C is lower than 150V, the voltage of the phase without voltage is restored by synthesizing the normal voltages of the remaining two phases; if the two-phase voltage connection piece is opened or loosened, that is, the voltage of any two of the three phases A, B, and C is lower than 150V, the voltage of the two phases without voltage is restored by shifting the normal voltage of the remaining phase; For the type of electricity theft caused by privately connecting a live wire, the theft current is synthesized through phasor calculation. The privately connected live wire electricity theft is manifested as the phase synthesis of the three-phase current A, B, and C in the electric energy meter not matching the zero-sequence current.

2. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 1 is characterized in that: When the one-phase voltage connecting piece is opened or loose, the phase synthesis calculation formula is: ， In the formula, is the voltage of the voltage-losing phase; , The remaining two phases are in normal voltage.

3. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 2 is characterized in that: The actual amount of electricity generated in the phase is calculated based on the voltage of the phase with depressurized voltage after phase synthesis and the current of the phase measured by the electric energy meter. The calculation formula is: ， In the formula, The actual amount of electricity generated in the pressure-loss phase; It is the voltage-loss phase current measured by the electric energy meter; for and The phase angle of .

4. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 3 is characterized in that: The calculation formula for the amount of electricity stolen when one phase voltage connection piece is opened or loose is: ， Where: To steal electricity; The electricity meter has measured the electricity in the phase where the voltage has been lost.

5. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 1 is characterized in that: When the two-phase voltage connecting piece is opened or loose, the normal voltage phase of the remaining phase is rotated 120° clockwise and counterclockwise to simulate the voltage loss of the two-phase voltage. The phase shift calculation formula is as follows: ， ， Where: , is the voltage of the two phases without voltage; The remaining phase voltage is normal.

6. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 5 is characterized in that: The actual amount of electricity generated in this phase is calculated based on the restored voltage of the depressurized phase and the current of this phase measured by the electric energy meter. The calculation formula is: ， ， Where: , They are the actual amount of electricity generated in the two phases under voltage loss; , They are respectively the voltage-loss two-phase currents measured by the electric energy meter; for and The phase angle of for and The phase angle of .

7. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 6 is characterized in that: The calculation formula for the amount of electricity stolen when the two-phase voltage connecting piece is opened or loose is: ， Where: To steal electricity; , They are the measured electricity quantities in the two phases when the electric energy meter loses voltage.

8. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 1 is characterized in that: The phasor synthesis calculation formula for the private connection of a live wire to steal electricity is as follows: ， Where: It is the electricity stealing current; , , They are the three-phase currents measured by the electric energy meter; It is the zero-sequence current measured by the electric energy meter.

9. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 8 is characterized in that: The amount of electricity theft is calculated based on the obtained electricity theft current and the phase voltage with the smallest absolute value of the phase angle with the electricity theft current. The calculation formula is: ， Where: To steal electricity; The stealing current The phase voltage with the smallest absolute value of the phase angle; for and The phase angle of .

10. The method for auxiliary calculation of electric quantity theft of three-phase four-wire direct access smart electric energy meter according to claim 1 is characterized in that: The electric energy meter used for the calculation of electricity theft caused by privately connecting a live wire must have a zero-sequence current measurement function.

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