Distribution network accurate metering system based on three-phase voltage transformer

Abstract

The invention relates to the technical field of three-phase voltage transformers, in particular to a distribution network accurate metering system based on a three-phase voltage transformer, which comprises a power grid monitoring unit, a resonance elimination unit and a power utilization metering unit, and is characterized in that the resonance elimination unit comprises an O-phase voltage transformer which is connected in series with a neutral point for damping to eliminate ferromagnetic resonance, and the power utilization metering unit; comprising a power supply voltage transformer which is respectively connected with an A-phase power supply, a B-phase power supply and a C-phase power supply and is used for metering the electricity consumption of an electricity consumption end, so that the electricity consumption of the electricity consumption end and the electricity consumption of a ring main unit are separately metered, and the electricity consumption metering precision is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of three-phase voltage transformers, and particularly to a precise power distribution metering system based on a three-phase voltage transformer. Background Art

[0002] In modern power systems, accurate electrical energy metering is of crucial significance for the stable operation of the power grid and the economic benefits of power enterprises. With the continuous development of the power distribution network and the improvement of the intelligent level, higher requirements are put forward for the accuracy and reliability of the metering system.

[0003] Chinese Patent Publication No.: CN111458549A discloses a new type of combined metering transformer, including an insulating wall-piercing sleeve, a sealing component, a sealing sleeve, and a socket with finger springs; thus, the above technical solution has the following problems: The windings for power supply and consumption metering and the metering windings of the ring main unit are made on one product, that is, they share one iron core. When powering the intelligent terminal and the operating power supply, the metering windings of the product will be seriously inaccurate, affecting the accuracy of metering. Summary of the Invention

[0004] Therefore, the present invention provides a precise power distribution metering system based on a three-phase voltage transformer to overcome the problem in the prior art that the windings for power supply and consumption metering and the metering windings of the ring main unit are made on one product, that is, they share one iron core. When powering the intelligent terminal and the operating power supply, the metering windings of the product will be seriously inaccurate, affecting the accuracy of metering.

[0005] To achieve the above object, the present invention provides a precise power distribution metering system based on a three-phase voltage transformer, including:

[0006] A power grid monitoring unit for metering the electrical energy of the power grid, including an A-phase voltage transformer connected to the A-phase power supply, a B-phase voltage transformer connected to the B-phase power supply, and a C-phase voltage transformer connected to the C-phase power supply;

[0007] A harmonic elimination unit including an O-phase voltage transformer connected in series with the neutral point to damp and eliminate ferromagnetic resonance;

[0008] An electricity consumption metering unit including power supply voltage transformers connected to the A-phase power supply, B-phase power supply, and C-phase power supply respectively for metering the electricity consumption at the power consumption end.

[0009] Further, the A-phase voltage transformer includes:

[0010] An A-phase primary coil for receiving the voltage signal of the A-phase power supply;

[0011] An A-phase iron core connected to the A-phase primary coil for receiving the voltage signal transmitted by the A-phase primary coil and transmitting it to the A-phase secondary coil side;

[0012] The A-phase fuse, which is connected to the terminals of the A-phase primary coil, is used to melt the fuse and cut off the circuit when the current exceeds the rated value, so as to protect the A-phase primary coil and the A-phase iron core from overcurrent damage.

[0013] The A-phase connecting wire, which is connected to the A-phase iron core and the A-phase secondary coil respectively, is used to provide electrical connection and ensure signal transmission.

[0014] Further, the B-phase voltage transformer includes:

[0015] The B-phase primary coil, which is used to receive the voltage signal of the B-phase power supply;

[0016] The B-phase iron core, which is connected to the B-phase primary coil, is used to receive the voltage signal transmitted by the B-phase primary coil and transmit it to the B-phase secondary coil side;

[0017] The B-phase fuse, which is connected to the terminals of the B-phase primary coil, is used to melt the fuse and cut off the circuit when the current exceeds the rated value, so as to protect the B-phase primary coil and the B-phase iron core from overcurrent damage.

[0018] The B-phase connecting wire, which is connected to the B-phase iron core and the B-phase secondary coil respectively, is used to provide electrical connection and ensure signal transmission.

[0019] Further, the C-phase voltage transformer includes:

[0020] The C-phase primary coil, which is used to receive the voltage signal of the C-phase power supply;

[0021] The C-phase iron core, which is connected to the C-phase primary coil, is used to receive the voltage signal transmitted by the C-phase primary coil and transmit it to the C-phase secondary coil side;

[0022] The C-phase fuse, which is connected to the terminals of the C-phase primary coil, is used to melt the fuse and cut off the circuit when the current exceeds the rated value, so as to protect the C-phase primary coil and the C-phase iron core from overcurrent damage.

[0023] The C-phase connecting wire, which is connected to the C-phase iron core and the C-phase secondary coil respectively, is used to provide electrical connection and ensure signal transmission.

[0024] Further, the power supply voltage transformer includes:

[0025] The primary coil of the power supply voltage transformer, which is used to receive the voltage signal between the ABC three-phase power supplies;

[0026] The independent voltage iron core, which is used to receive the voltage signal transmitted by the primary coil of the power supply voltage transformer and transmit it to the independent power supply secondary coil side.

[0027] Further, the power supply voltage transformer further includes:

[0028] A first power supply voltage transformer, which is respectively connected to the A-phase power supply and the B-phase power supply, and is used for measuring the voltage between the A-phase and B-phase power supplies to measure the power consumption at the power consumption end;

[0029] A second power supply voltage transformer, which is respectively connected to the B-phase power supply and the C-phase power supply, and is used for measuring the voltage between the B-phase and C-phase power supplies to measure the power consumption at the power consumption end.

[0030] Further, the O-phase voltage transformer includes:

[0031] An O-phase primary coil, which is used for receiving the neutral line voltage signal;

[0032] An O-phase iron core, which is used for receiving the voltage signal transmitted by the O-phase primary coil and transmitting it to the O-phase secondary coil side;

[0033] An O-phase connecting wire, which is used for connecting the O-phase primary coil and the circuit on the O-phase secondary coil side;

[0034] An O-phase terminal, which is connected to the terminal of the O-phase primary coil and is used for providing electrical connection to ensure signal transmission.

[0035] Further, an N-phase terminal, which is connected to the ground and is used for ensuring reliable grounding of the neutral point;

[0036] An N-phase connecting wire, which is connected to the terminal of the O-phase primary coil and is used for transmitting unbalanced current to ensure that the current can smoothly return to the power supply.

[0037] Further, each transformer is cast together with epoxy resin to form an integral body to meet the requirements of the small volume of the ring main unit.

[0038] Further, the power supply voltage transformer and each phase voltage transformer for metering have independent coils and wirings; each transformer is grounded by spraying conductive paint on the outside.

[0039] Compared with the prior art, the beneficial effect of the present invention is that by separately designing the power supply voltage transformer for metering and the A-phase voltage transformer, B-phase voltage transformer, and C-phase voltage transformer for power supply metering, the accuracy of the transformer for metering is ensured without being affected during power supply. The power supply voltage transformer passes through the A-phase power supply, B-phase power supply, and C-phase power supply, while the voltage transformer for the ring main unit measures the voltage through the A-phase power supply, B-phase power supply, C-phase power supply, and the neutral line. The two do not interfere with each other, realizing the advantages of the 6PT design and improving the accuracy of the metering device. Description of the Drawings

[0040] Figure 1It is the wiring schematic diagram of the power grid monitoring unit, harmonic elimination unit and power consumption metering unit in the embodiment of the present invention;

[0041] Figure 2 It is the right view sectional view of the cable plug of the voltage transformer of the independent power supply in the embodiment of the present invention;

[0042] Figure 3 It is the front view sectional view of the cable plug of the voltage transformer of the independent power supply in the embodiment of the present invention;

[0043] Figure 4 It is the top view sectional view of the cable plug of the voltage transformer of the independent power supply in the embodiment of the present invention;

[0044] Figure 5 It is the wiring schematic diagram of the power grid monitoring unit, harmonic elimination unit and power consumption metering unit in another embodiment of the present invention;

[0045] In the figure: 1. Core of phase A; 2. Core of phase B; 3. Core of phase C; 4. Primary coil of phase A; 5. Primary coil of phase B; 6. Primary coil of phase C; 7. Core of phase O; 8. Primary coil of phase O; 9. Independent voltage core; 10. Primary coil of the power supply voltage transformer; 11. Fuse of phase A; 12. Fuse of phase B; 13. Fuse of phase C; 14. Terminal of phase O; 15. Terminal of phase N; 16. Connecting wire of phase A; 17. Connecting wire of phase B; 18. Connecting wire of phase C; 19. Connecting wire of phase O; 20. Connecting wire of phase N; 21. Independent metering connecting wire of phase B; 22. Independent metering connecting wire of phase C. Detailed implementation manners

[0046] In order to make the objectives and advantages of the present invention more clear and understandable, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0048] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0049] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Please refer to Figure 1 as shown, which is the wiring schematic diagram of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit in the embodiment of the present invention; An accurate power distribution metering system based on a three-phase voltage transformer according to an embodiment of the present invention includes:

[0051] A power distribution network (not shown in the figure), which includes several ring main units for distributing electric power;

[0052] A temperature control unit (not shown in the figure), which is used for temperature and humidity regulation control inside the ring main unit;

[0053] A power grid monitoring unit, which is arranged inside the ring main unit;

[0054] A harmonic elimination unit; which is arranged inside the ring main unit;

[0055] A power consumption metering unit, which is arranged inside the ring main unit;

[0056] A communication unit (not shown in the figure), which is used to transmit the electrical signals detected by the power grid monitoring unit;

[0057] A data acquisition unit (not shown in the figure), which is connected to the communication unit, and is used to filter and amplify the electrical signals to remove noise and interference, and calculate and store the electrical energy related parameters according to the processed signals. The electrical energy related parameters include voltage, current, power, and the load of the ring main unit;

[0058] An analysis unit (not shown in the figure), which is respectively connected to the temperature control unit, the power grid monitoring unit, the harmonic elimination unit, the power consumption metering unit, the communication unit, and the data acquisition unit, and is used to determine whether the operating conditions of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are qualified based on the power consumption fluctuation factor and the expected power consumption frequency, and when it is determined that the operating conditions of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are unqualified, issue corresponding alarm information based on the factor difference amount;

[0059] An alarm unit (not shown in the figure), which is connected to the analysis unit, and is used to issue corresponding alarm information based on the determination result of the analysis unit.

[0060] Specifically, the temperature control unit can be a WHD48 temperature and humidity controller, which can reasonably prevent equipment failures caused by low temperature and high temperature, as well as electric leakage and flashover accidents caused by moisture or condensation. The WHD48 temperature and humidity controller is installed in an embedded panel. First, a square slot of a specified size is made on the cabinet panel. After the device is removed from the bracket, it is embedded in the slot, and then the bracket is pushed into the card slot and locked.

[0061] Please continue to refer to Figure 1 As shown, it is the wiring schematic diagram of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit in the embodiment of the present invention; the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit of the present invention are arranged in the ring main unit.

[0062] The power grid monitoring unit is used to measure the electric energy of the power grid, including an A-phase voltage transformer connected to the A-phase power supply, a B-phase voltage transformer connected to the B-phase power supply, and a C-phase voltage transformer connected to the C-phase power supply.

[0063] The harmonic elimination unit includes a O-phase voltage transformer connected in series with the neutral point to act as a damper to eliminate ferromagnetic resonance.

[0064] The power consumption metering unit includes a power supply voltage transformer connected to the B-phase power supply and the C-phase power supply, which is used to measure the power consumption at the power consumption end.

[0065] Figure 1 In, JB1 is the primary coil 10 of the power supply voltage transformer, jb2 is the secondary coil of the power supply voltage transformer, A is the A-phase power supply, B is the B-phase power supply, C is the C-phase power supply, O and o are both ground wires, N and n are both neutral lines, A1 is the primary coil of the A-phase voltage transformer, B1 is the primary coil of the B-phase voltage transformer, C1 is the primary coil of the C-phase voltage transformer, 1a is the first secondary coil of the A-phase voltage transformer, 2a is the second secondary coil of the A-phase voltage transformer, da is the third secondary coil of the A-phase voltage transformer; 1b is the first secondary coil of the B-phase voltage transformer, 2b is the second secondary coil of the B-phase voltage transformer, dn1 is the third secondary coil of the B-phase voltage transformer; 1c is the first secondary coil of the C-phase voltage transformer, 2c is the second secondary coil of the C-phase voltage transformer, dn2 is the third secondary coil of the C-phase voltage transformer; N1 is the primary coil of the O-phase voltage transformer, n2 is the first secondary coil of the O-phase voltage transformer, n3 is the second secondary coil of the O-phase voltage transformer;

[0066] 1a, 1b, and 1c are used to measure the voltage values between the power supplies of each phase respectively to detect the voltage stability between the power supplies of each phase. 2a, 2b, and 2c are used to output power for the ring main unit, N1 and n2 are used to eliminate resonance, and da, dn1, dn2, and n3 are connected end to end for grounding protection;

[0067] jb2 is used to measure the power consumption of the external power-consuming terminal;

[0068] The power supply voltage transformer of the power consumption metering unit is powered by three phases of ABC. The power supply voltage transformer is used to provide power for the external power-consuming terminal.

[0069] The power supply voltage transformer and each phase voltage transformer for metering have independent coils and wiring.

[0070] Each transformer is cast together with epoxy resin to form an integral body, meeting the requirements of the small volume of the ring main unit. In the design, by separating the transformers for power supply and metering, ferroresonance is reliably suppressed, and the stability of the system is improved.

[0071] The core magnetic flux density is designed in a lower range, and the transformer is in the linear operation area. When the transformers for power supply and metering are not separated, the transformer bears various complex working conditions and interferences at the same time, and is prone to enter the saturation state, creating conditions for ferroresonance. After separating the transformers for power supply and metering, the loads of the two are independent and clear, avoiding interference and influence between each other, and reliably suppressing ferroresonance.

[0072] Please refer to Figure 2 、 Figure 3 and Figure 4 shown respectively. They are the right view sectional view, front view sectional view and top view sectional view of the cable plug of the voltage transformer of the independent power supply in the embodiment of the present invention;

[0073] The A-phase voltage transformer of the present invention includes:

[0074] The A-phase primary coil 4, which is used to receive the voltage signal of the A-phase power supply;

[0075] The A-phase iron core 1, which is connected to the A-phase primary coil 4, is used to receive the voltage signal transmitted by the A-phase primary coil 4 and transmit it to the A-phase secondary coil (not shown in the figure);

[0076] The A-phase fuse 11, which is connected to the terminal of the A-phase primary coil 4, is used to fuse the fuse when the current exceeds the rated value, cut off the circuit, and protect the A-phase primary coil 4 and the A-phase iron core 1 from overcurrent damage.

[0077] The A-phase connection line 16, which is respectively connected to the A-phase iron core 1 and the A-phase secondary coil, is used to provide electrical connection and ensure signal transmission.

[0078] The B-phase voltage transformer includes:

[0079] The B-phase primary coil 5, which is used to receive the voltage signal of the B-phase power supply;

[0080] The B-phase iron core 2 is connected to the B-phase primary coil 5 to receive the voltage signal transmitted by the B-phase primary coil 5 and transmit it to the B-phase secondary coil (not shown in the figure).

[0081] The B-phase fuse 12 is connected to the terminal of the B-phase primary coil 5. When the current exceeds the rated value, the fuse melts to cut off the circuit, protecting the B-phase primary coil 5 and the B-phase iron core 2 from overcurrent damage.

[0082] The B-phase connecting wire 17 is connected to the B-phase iron core 2 and the B-phase secondary coil respectively to provide electrical connection and ensure signal transmission.

[0083] The C-phase voltage transformer includes:

[0084] The C-phase primary coil 6 is used to receive the voltage signal of the C-phase power supply.

[0085] The C-phase iron core 3 is connected to the C-phase primary coil 6 to receive the voltage signal transmitted by the C-phase primary coil 6 and transmit it to the C-phase secondary coil (not shown in the figure).

[0086] The C-phase fuse 13 is connected to the terminal of the C-phase primary coil 6. When the current exceeds the rated value, the fuse melts to cut off the circuit, protecting the C-phase primary coil 6 and the C-phase iron core 3 from overcurrent damage.

[0087] The C-phase connecting wire 18 is connected to the C-phase iron core 3 and the C-phase secondary coil respectively to provide electrical connection and ensure signal transmission.

[0088] The power supply voltage transformer includes:

[0089] The primary coil 10 of the power supply voltage transformer is used to receive the voltage signal between the ABC three-phase power supplies.

[0090] The independent voltage iron core 9 is used to receive the voltage signal transmitted by the primary coil 10 of the power supply voltage transformer and transmit it to the independent power supply secondary coil (not shown in the figure).

[0091] The independent metering B-phase connecting wire 21 is respectively connected to the B-phase power supply and one side terminal of the primary coil 10 of the power supply voltage transformer.

[0092] The independent metering C-phase connecting wire 22 is respectively connected to the C-phase power supply and the side terminal of the primary coil 10 of the power supply voltage transformer far from the B-phase power supply.

[0093] The O-phase voltage transformer includes:

[0094] The O-phase primary coil 8 is used to receive the neutral line voltage signal.

[0095] The O-phase iron core 7 is used to receive the voltage signal transmitted by the O-phase primary coil 8 and transmit it to the O-phase secondary coil (not shown in the figure);

[0096] The O-phase connection line 19 is used to connect the O-phase primary coil 8 and the circuit on the O-phase secondary coil side;

[0097] The O-phase terminal 14 is connected to the terminal of the O-phase primary coil 8 to provide electrical connection and ensure signal transmission.

[0098] The N-phase terminal 15 is connected to the ground to ensure reliable grounding of the neutral point;

[0099] The N-phase connection line 20 is connected to the terminal of the O-phase primary coil 8 to transmit unbalanced current and ensure that the current can return to the power supply smoothly.

[0100] Specifically, the cable plug and the connector are well sealed. The voltage transformer is internally cast with epoxy resin and externally sprayed with conductive paint for grounding. This voltage transformer is easy to install and has high usage safety, and is used in ring main units and gas-insulated switchgear.

[0101] Please refer to Figure 5 As shown, it is the wiring schematic diagram of the power grid monitoring unit, harmonic elimination unit and power consumption metering unit of another embodiment of the present invention. The power consumption metering unit of the present invention may include a first power voltage transformer respectively connected to the A-phase power supply and the B-phase power supply for measuring the power consumption of the power consumption end, and a second power voltage transformer respectively connected to the B-phase power supply and the C-phase power supply for measuring the power consumption of the power consumption end.

[0102] Figure 5Among them, JA1 is the primary coil of the first power voltage transformer, ja2 is the secondary coil of the first power voltage transformer, JB1 is the primary coil of the second power voltage transformer, and jb2 is the secondary coil of the second power voltage transformer; A is the A-phase power supply, B is the B-phase power supply, C is the C-phase power supply, O and o are both ground wires, N and n are both neutral wires, A1 is the primary coil of the A-phase voltage transformer, B1 is the primary coil of the B-phase voltage transformer, C1 is the primary coil of the C-phase voltage transformer, 1a is the first secondary coil of the A-phase voltage transformer, 2a is the second secondary coil of the A-phase voltage transformer, and da is the third secondary coil of the A-phase voltage transformer; 1b is the first secondary coil of the B-phase voltage transformer, 2b is the second secondary coil of the B-phase voltage transformer, and db is the third secondary coil of the B-phase voltage transformer; 1c is the first secondary coil of the C-phase voltage transformer, 2c is the second secondary coil of the C-phase voltage transformer, and dc is the third secondary coil of the C-phase voltage transformer; N1 is the primary coil of the O-phase voltage transformer, n2 is the first secondary coil of the O-phase voltage transformer, n3 is the second secondary coil of the O-phase voltage transformer, and H is an alarm component;

[0103] 1a, 1b, and 1c are used to measure the voltage values between each phase of the power supply respectively to detect the voltage stability between each phase of the power supply. 2a, 2b, and 2c are used to output power for the ring main unit, N1 and n2 are used to eliminate resonance, and da, db, dc, and n3 are connected end to end for grounding protection;

[0104] jb2 is used to measure the power consumption of the external power consumption end;

[0105] Specifically, the specific structure of H is not limited. It can be a warning light that emits light when any power supply fails in the ABC three-phase power supply, or it can be externally connected to a microcomputer harmonic elimination device. Those skilled in the art can understand that it can achieve the indication and reminder function when any power supply fails in the ABC three-phase power supply. This is the prior art and will not be elaborated here.

[0106] The power voltage transformer of the power consumption metering unit is powered by the ABC three-phase power supply, and the power voltage transformer is used for power consumption metering of the external power consumption end;

[0107] Specifically, the analysis unit is used to determine whether the operation status of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit is qualified based on the power consumption fluctuation factor, including:

[0108] Periodically determine the power consumption of the power consumption end based on the parameters obtained by the data acquisition unit;

[0109] Draw the time-domain curve of power consumption within the current detection period based on the power consumption determined in each pilot period, and record the absolute value of the difference between the maximum value and the minimum value in the time-domain curve of power consumption as the power consumption fluctuation factor;

[0110] If the power consumption fluctuation factor is less than or equal to the first preset power consumption fluctuation factor, it is determined that the operating conditions of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are qualified, and the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are controlled to continue operating with the current operating parameters;

[0111] If the power consumption fluctuation factor is less than or equal to the second preset power consumption fluctuation factor and greater than the first preset power consumption fluctuation factor, it is determined whether the operating conditions of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are qualified based on the expected power consumption frequency;

[0112] If the power consumption fluctuation factor is greater than the second preset power consumption fluctuation factor, it is determined that the operating conditions of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are unqualified, and the alarm unit is controlled to send corresponding alarm information based on the factor difference amount.

[0113] Specifically, the first power consumption fluctuation factor Y1 is selected within the interval [0.19D0, 0.28D0]; the second preset power consumption fluctuation factor Y2 is selected within the interval [0.42D0, 0.58D0], where D0 is the average value of the power consumption of each pilot period obtained from historical data, and the unit is MWh.

[0114] Specifically, the analysis module is used to determine whether the operating conditions of the mutual inductance module are qualified based on the expected power consumption frequency, including:

[0115] Solve the average value of the average peaks of each historical power consumption time-domain curve to obtain the expected power consumption anchor point;

[0116] Solve the peak variance of the peaks of each historical power consumption time-domain curve, and determine the positive and negative deviations of the expected power consumption anchor point based on the peak variance;

[0117] The increase amplitude of the peak variance is proportional to the deviation value of the positive and negative deviations of the expected power consumption anchor point;

[0118] In this embodiment, optionally,

[0119] Compare the peak variance with the first preset peak variance and the second preset peak variance;

[0120] If the peak variance is less than or equal to the first preset peak variance, adjust the deviation value of the positive and negative deviations of the expected power consumption anchor point to 1.11 times the initial deviation value;

[0121] If the peak variance is less than or equal to the second preset peak variance and greater than the first preset peak variance, adjust the deviation value of the positive and negative deviations of the expected power consumption anchor point to 1.21 times the initial deviation value;

[0122] If the peak variance is greater than the second preset peak variance, adjust the deviation values of the positive and negative deviations of the expected power consumption anchor point to 1.29 times the initial deviation value;

[0123] The first preset peak variance is taken as 0.09F0 2 , and the second preset peak variance is taken as 0.25F0 2 , where F0 is the average value of the peaks of the historical power consumption time-domain curves, and the unit of the preset peak variance is MWh 2 .

[0124] The expected power consumption frequency is the number of peaks in the current power consumption time-domain curve that are within the expected power consumption interval;

[0125] The expected power consumption interval is the expected power consumption anchor point plus or minus the deviation value;

[0126] If the expected power consumption frequency is less than or equal to the preset expected power consumption frequency, control the alarm unit to send the corresponding alarm information based on the factor difference;

[0127] If the expected power consumption frequency is greater than the preset expected power consumption frequency, increase the first preset power consumption fluctuation factor and the second preset power consumption fluctuation factor to the corresponding values based on the expected power consumption frequency.

[0128] Based on the power consumption fluctuation factor, determine whether the operating conditions of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit are qualified. The power consumption fluctuation factor characterizes the power consumption fluctuation situation at the power consumption end. Monitor the power consumption fluctuation situation at the power consumption end to detect and identify abnormal situations in a timely manner. When the power consumption fluctuation factor is greater than the second preset power consumption fluctuation factor, it is determined that the operating conditions of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit are unqualified, and control the alarm unit to send the corresponding alarm information based on the factor difference; when the power consumption fluctuation factor is less than or equal to the second preset power consumption fluctuation factor and greater than the first preset power consumption fluctuation factor, it is impossible to determine the status of the current power grid monitoring unit, harmonic elimination unit, and power consumption metering unit only based on the power consumption fluctuation situation. At this time, comprehensively determine whether the operating conditions of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit are qualified in combination with the expected power consumption frequency;

[0129] Determine the expected power consumption anchor point, and determine the expected power consumption interval in combination with the peak variance; the expected power consumption frequency further characterizes the power consumption abnormality at the power consumption end through the analysis of historical data. When the expected power consumption frequency is greater than the preset expected power consumption frequency, it indicates that the power consumption peak situation at the power consumption end conforms to the historical data law, and further adjust the first preset power consumption fluctuation factor and the second preset power consumption fluctuation factor to lower the evaluation standard, and further comprehensively determine the specific situation of the power consumption end according to the detection parameters; while timely capturing the abnormal situations of the power grid monitoring unit, harmonic elimination unit, and power consumption metering unit, the detection and metering accuracy for the distribution network is further improved.

[0130] The preset expected power consumption frequency P0 is selected within the range [0.7M0, 0.8M0], where M0 is the average value of the historical expected power consumption frequencies.

[0131] The analysis unit adjusts the first preset power consumption fluctuation factor and the second preset power consumption fluctuation factor to corresponding values based on the expected power consumption frequency, where:

[0132] The increase amplitudes of the first preset power consumption fluctuation factor and the second preset power consumption fluctuation factor are positively correlated with the expected power consumption frequency.

[0133] In this embodiment, optionally,

[0134] If the expected power consumption frequency is less than or equal to the first frequency comparison threshold, the first preset power consumption fluctuation factor is adjusted to 1.11 times the initial first preset power consumption fluctuation factor, and the second preset power consumption fluctuation factor is adjusted to 1.11 times the initial second preset power consumption fluctuation factor;

[0135] If the expected power consumption frequency is less than or equal to the second frequency comparison threshold and greater than the first frequency comparison threshold, the first preset power consumption fluctuation factor is adjusted to 1.23 times the initial first preset power consumption fluctuation factor, and the second preset power consumption fluctuation factor is adjusted to 1.23 times the initial second preset power consumption fluctuation factor;

[0136] If the expected power consumption frequency is greater than the second frequency comparison threshold, the first preset power consumption fluctuation factor is adjusted to 1.31 times the initial first preset power consumption fluctuation factor, and the second preset power consumption fluctuation factor is adjusted to 1.29 times the initial second preset power consumption fluctuation factor;

[0137] The first frequency comparison threshold is taken as 1.3P0, and the second frequency comparison threshold is taken as 1.7P0.

[0138] Specifically, the analysis unit controls the alarm unit to send corresponding alarm information based on the factor difference amount, including:

[0139] The difference between the power consumption fluctuation factor and the second preset power consumption fluctuation factor is denoted as the factor difference amount;

[0140] If the factor difference amount is less than or equal to the first preset factor difference amount, the temperature control unit is controlled based on the factor difference amount to lower the internal temperature of the ring main unit to the corresponding value;

[0141] If the factor difference amount is less than or equal to the second preset factor difference amount and greater than the first preset factor difference amount, the alarm unit is controlled based on the fluctuation tendency parameter to send corresponding alarm information;

[0142] If the factor difference amount is greater than the second preset factor difference amount, the alarm unit is controlled based on the time deviation parameter to send corresponding alarm information.

[0143] The first preset factor difference amount C1 is 1.21Y2, and the second preset factor difference amount C2 is 1.34Y2.

[0144] Based on the factor difference control alarm unit, a corresponding alarm message is issued. When the factor difference is less than or equal to the first preset factor difference, the performance of the internal components of the mutual inductor in the ring main unit changes due to working in a high temperature environment. The iron core of the mutual inductor will experience magnetic saturation at high temperature, causing its output signal to be distorted, thereby affecting the metering accuracy of the electric energy meter, resulting in the detected power consumption being lower than the actual power consumption, thereby causing the power consumption fluctuation factor to be larger. In view of this situation, the internal temperature of the ring main unit is adjusted to ensure accurate metering.

[0145] Specifically, the analysis unit is used to control the alarm unit to issue corresponding alarm information based on the fluctuation tendency parameter, including:

[0146] Based on the expected power consumption frequency of each historical power consumption time domain curve, an expected power consumption frequency time domain curve is drawn, and the slope of the expected power consumption frequency time domain curve at the current time node is recorded as a fluctuation tendency parameter;

[0147] If the fluctuation tendency parameter is greater than the preset fluctuation tendency parameter, the temperature control unit is controlled based on the factor difference to lower the internal temperature of the ring main unit to a corresponding value;

[0148] If the fluctuation tendency parameter is less than or equal to the preset fluctuation tendency parameter, the alarm unit is controlled to issue a corresponding alarm message based on the time deviation parameter.

[0149] The default volatility tendency parameter is 0.

[0150] When the factor difference is less than or equal to the second preset factor difference and greater than the first preset factor difference, the specific conditions of the power grid monitoring unit, the detuning unit and the electricity metering unit are further analyzed in combination with the fluctuation tendency parameter. The fluctuation tendency parameter characterizes the changes in the abnormal power consumption at the power consumption end. When the fluctuation tendency parameter is greater than the preset fluctuation tendency parameter, the expected power consumption frequency gradually increases. For the case where the detection data obtained by the power grid monitoring unit, the detuning unit and the electricity metering unit gradually stabilize and the power fluctuation factor is large, it is determined that the output signal of the mutual inductor is distorted, affecting the metering accuracy, and the current detection accuracy is gradually stable. At this time, the temperature control unit fine-tunes the internal temperature of the ring network cabinet to further ensure stable metering of electricity consumption.

[0151] Specifically, the analysis unit is used to control the alarm unit to issue corresponding alarm information based on the time deviation parameter, including:

[0152] To solve the interval average value of the time intervals of the peak values ​​of the current power consumption time domain curve within the expected power consumption range;

[0153] Obtain the ratio of the time interval between the time node of the peak value within the expected power consumption interval in the power consumption time domain curve closest to the current time node and the time node of the previous peak value within the expected power consumption interval to the interval average value, so as to obtain the time deviation parameter.

[0154] If the time deviation parameter is less than or equal to the preset time deviation parameter, control the alarm unit to send an alarm message for the insulation abnormality of the voltage transformer;

[0155] If the time deviation parameter is greater than the preset time deviation parameter, control the alarm unit to send an alarm message for the abnormality of the communication module;

[0156] The preset time deviation parameter is selected within the interval [1.52, 2.63].

[0157] In the case where the abnormal deviation of the power consumption fluctuation factor appears significantly, control the alarm unit to send the corresponding alarm message based on the time deviation parameter. At this time, the power consumption is too low, resulting in an excessive power consumption fluctuation factor. The time deviation parameter characterizes the abnormal duration of the detection data. When the time deviation parameter is less than or equal to the preset time deviation parameter, it is determined that due to a fault in the three-phase voltage transformer, such as winding short circuit, insulation damage, etc., the output voltage signal is inaccurate, resulting in a large error in the processing of power parameters; when the time deviation parameter is greater than the preset time deviation parameter, in this case, the abnormal duration is too long. Due to the communication module failure, the data transmission between the metering system and external devices will be interrupted, so that the power metering data of the distribution network cannot be obtained in real time, and the operation state of the distribution network cannot be grasped in time, and an alarm for the abnormal situation is given in time to ensure that the metering can be guaranteed for the power consumption end in various complex environments.

[0158] Based on the factor difference amount, control the temperature control unit to lower the internal temperature of the ring main unit to the corresponding value, where:

[0159] The reduction amplitude of the internal temperature of the ring main unit is proportional to the factor difference amount.

[0160] In this embodiment, optionally,

[0161] Compare the factor difference amount with the first difference amount comparison threshold and the second difference amount comparison threshold;

[0162] If the factor difference amount is less than or equal to the first difference amount comparison threshold, reduce the internal temperature of the ring main unit to 0.92 times the initial temperature;

[0163] If the factor difference amount is less than or equal to the second difference amount comparison threshold and greater than the first difference amount comparison threshold, reduce the internal temperature of the ring main unit to 0.84 times the initial temperature;

[0164] If the factor difference amount is greater than the second difference amount comparison threshold, the internal temperature of the ring main unit is reduced to 0.75 times the initial temperature;

[0165] The first difference amount comparison threshold is taken as 1.1C2, and the second difference amount comparison threshold is taken as 1.3C2.

[0166] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

[0167] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A distribution network accurate metering system based on three-phase voltage transformer, characterized in that: include: A power grid monitoring unit, which is used to measure power grid electric energy, includes an A-phase voltage transformer connected to an A-phase power supply, a B-phase voltage transformer connected to a B-phase power supply, and a C-phase voltage transformer connected to a C-phase power supply; A detuning unit, comprising an O-phase voltage transformer connected in series with the neutral point for damping to eliminate ferromagnetic resonance; The power consumption metering unit comprises power supply voltage transformers respectively connected to the A-phase power supply, the B-phase power supply and the C-phase power supply for measuring the power consumption at the power consumption end.

2. The distribution network precise metering system based on three-phase voltage transformer according to claim 1 is characterized in that: The A-phase voltage transformer comprises: A-phase primary coil, used for receiving the voltage signal of A-phase power supply; An A-phase iron core connected to the A-phase primary coil to receive a voltage signal transmitted by the A-phase primary coil and transmit the voltage signal to the A-phase secondary coil side; A-phase fuse, connected to the terminal of the A-phase primary coil, is used for melting the fuse and cutting off the circuit when the current exceeds the rated value, so as to protect the A-phase primary coil and the A-phase iron core from damage by overcurrent; A is connected to the A phase iron core and the A phase secondary coil respectively to provide electrical connection to ensure signal transmission.

3. The distribution network precise metering system based on three-phase voltage transformer according to claim 2 is characterized in that: The B-phase voltage transformer comprises: A B-phase primary coil, which is used to receive a voltage signal of a B-phase power supply; A B-phase iron core connected to the B-phase primary coil to receive a voltage signal transmitted by the B-phase primary coil and transmit it to the B-phase secondary coil side; A B-phase fuse connected to the terminal of the B-phase primary coil, so that when the current exceeds the rated value, the fuse is blown to cut off the circuit to protect the B-phase primary coil and the B-phase iron core; B connecting wiring, which is connected to the B-phase iron core and the B-phase secondary coil respectively to provide electrical connection.

4. The distribution network precise metering system based on three-phase voltage transformer according to claim 3 is characterized in that: The C-phase voltage transformer comprises: A C-phase primary coil, which is used to receive a voltage signal of a C-phase power supply; A C-phase iron core connected to the C-phase primary coil to receive a voltage signal transmitted by the C-phase primary coil and transmit it to the C-phase secondary coil side; The C-phase fuse is connected to the terminal of the C-phase primary coil, so that when the current exceeds the rated value, the fuse will blow and cut off the circuit to protect the C-phase primary coil and the C-phase iron core from damage due to overcurrent; the C-phase connecting wiring is connected to the C-phase iron core and the C-phase secondary coil respectively, so as to provide electrical connection and ensure signal transmission.

5. The distribution network precise metering system based on three-phase voltage transformer according to claim 4 is characterized in that: The power supply voltage transformer comprises: The primary coil of the power supply voltage transformer is used to receive the voltage signal between the ABC three-phase power supplies; The independent voltage core is used to receive the voltage signal transmitted by the primary coil of the power supply voltage transformer and transmit it to the secondary coil side of the independent power supply.

6. The distribution network precise metering system based on three-phase voltage transformer according to claim 5 is characterized in that: The power supply voltage transformer also includes: A first power supply voltage transformer, which is connected to the A-phase power supply and the B-phase power supply respectively, and is used to measure the voltage between the A-phase power supply and the B-phase power supply, so as to measure the power consumption of the power consumption end; The second power supply voltage transformer is connected to the B-phase power supply and the C-phase power supply respectively, and is used to measure the voltage between the B-phase power supply and the C-phase power supply, so as to measure the power consumption of the power consumption end.

7. The distribution network precise metering system based on three-phase voltage transformer according to claim 6 is characterized in that: The O-phase voltage transformer comprises: O-phase primary coil, which is used to receive a neutral line voltage signal; The O-phase iron core is used to receive the voltage signal transmitted by the O-phase primary coil and transmit it to the O-phase secondary coil side; O-connected wiring, which is used to connect the O-phase primary coil and the O-phase secondary coil side circuit; The O-phase terminal is connected to the terminal of the O-phase primary coil to provide an electrical connection to ensure signal transmission.

8. The distribution network precise metering system based on three-phase voltage transformer according to claim 7 is characterized in that: The N-phase terminal is connected to the ground to ensure that the neutral point is firmly grounded; The N-connected wiring is connected to the terminal of the O-phase primary coil to transmit unbalanced current.

9. The distribution network precise metering system based on three-phase voltage transformer according to claim 8 is characterized in that: The transformers are cast together with epoxy resin to form a whole.

10. The distribution network precise metering system based on three-phase voltage transformer according to claim 9 is characterized in that: The power supply voltage transformer and each phase voltage transformer used for measurement have independent coils and wiring; each transformer is sprayed with conductive paint for grounding.

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