A distribution network accurate metering system based on three-phase voltage transformer

Abstract

The present application relates to the technical field of three-phase voltage transformer, and more particularly to a distribution network accurate metering system based on three-phase voltage transformer, which comprises a power grid monitoring unit, a harmonic elimination unit and a power consumption metering unit, the harmonic elimination unit comprises an O-phase voltage transformer connected in series with the neutral point to eliminate ferroresonance, and the power consumption metering unit comprises power supply voltage transformers connected with A-phase power supply, B-phase power supply and C-phase power supply respectively to meter the power consumption of the power consumption end, so as to realize separate metering of the power consumption of the power consumption end and the ring network cabinet and effectively improve the power consumption metering accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of three-phase voltage transformers, and particularly relates to a distribution network accurate metering system based on a three-phase voltage transformer. BACKGROUND

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

[0003] Chinese patent CN111458549A discloses a novel combined metering transformer, which comprises an insulating wall bushing, a sealing assembly, a sealing sleeve and a jack with a contact finger spring. It can be seen that the above technical solution has the following problems: the winding for power supply and consumption metering and the ring network cabinet metering winding are made on one product, that is, they share one iron core. When power is supplied to the intelligent terminal and the operating power supply, the product metering winding will be seriously inaccurate, affecting the accuracy of metering. SUMMARY

[0004] Therefore, the present application provides a distribution network accurate metering system based on a three-phase voltage transformer to overcome the problem that the winding for power supply and consumption metering and the ring network cabinet metering winding are made on one product, that is, they share one iron core. When power is supplied to the intelligent terminal and the operating power supply, the product metering winding will be seriously inaccurate, affecting the accuracy of metering.

[0005] To achieve the above purpose, the present application provides a distribution network accurate metering system based on a three-phase voltage transformer, which comprises:

[0006] A power grid monitoring unit for metering power grid power, comprising 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;

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

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

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

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

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

[0012] A phase fuse connected to the terminals of the A phase primary coil for fusing the fuse to cut off the circuit when the current exceeds the rated value, thereby protecting the A phase primary coil and the A phase core from overcurrent damage.

[0013] An A phase connecting line connected to the A phase core and the A phase secondary coil respectively for providing electrical connection and ensuring signal transmission.

[0014] Further, the B phase voltage transformer comprises:

[0015] A B phase primary coil for receiving the voltage signal of the B phase power supply;

[0016] A B phase core connected to the B phase primary coil for receiving the voltage signal transmitted by the B phase primary coil and transmitting it to the B phase secondary coil side;

[0017] A B phase fuse connected to the terminals of the B phase primary coil for fusing the fuse to cut off the circuit when the current exceeds the rated value, thereby protecting the B phase primary coil and the B phase core from overcurrent damage.

[0018] A B phase connecting line connected to the B phase core and the B phase secondary coil respectively for providing electrical connection and ensuring signal transmission.

[0019] Further, the C phase voltage transformer comprises:

[0020] A C phase primary coil for receiving the voltage signal of the C phase power supply;

[0021] A C phase core connected to the C phase primary coil for receiving the voltage signal transmitted by the C phase primary coil and transmitting it to the C phase secondary coil side;

[0022] A C phase fuse connected to the terminals of the C phase primary coil for fusing the fuse to cut off the circuit when the current exceeds the rated value, thereby protecting the C phase primary coil and the C phase core from overcurrent damage.

[0023] A C phase connecting line connected to the C phase core and the C phase secondary coil respectively for providing electrical connection and ensuring signal transmission.

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

[0025] A primary coil of the power supply voltage transformer for receiving the voltage signal between the ABC three-phase power supply;

[0026] An independent voltage core for receiving the voltage signal transmitted by the primary coil of the power supply voltage transformer and transmitting it to the independent power supply secondary coil side.

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

[0028] a first power supply voltage transformer connected with the A-phase power supply and the B-phase power supply respectively, for measuring the voltage between the A-phase power supply and the B-phase power supply, and for measuring the power consumption of the power consumption end;

[0029] a second power supply voltage transformer connected with the B-phase power supply and the C-phase power supply respectively, for measuring the voltage between the B-phase power supply and the C-phase power supply, and for measuring the power consumption of the power consumption end.

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

[0031] an O-phase primary coil for receiving a neutral line voltage signal;

[0032] an O-phase iron core 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 for connecting the O-phase primary coil and the O-phase secondary coil side circuit;

[0034] an O-phase terminal connected with the terminal of the O-phase primary coil, for providing electrical connection and ensuring signal transmission.

[0035] Further, an N-phase terminal connected with the ground, for ensuring firm neutral point grounding;

[0036] an N-phase connecting wire connected with the terminal of the O-phase primary coil, for transmitting unbalanced current and ensuring that the current can return to the power supply smoothly.

[0037] Further, the transformers are cast together by epoxy resin to form an integral whole, so as to meet the requirement of small volume of the ring network cabinet.

[0038] Further, the power supply voltage transformer and the phase voltage transformers for measurement each have independent coils and connecting wires; the transformers are externally sprayed with conductive paint and grounded.

[0039] Compared with the prior art, the beneficial effects of the present application are that, by separately designing the power supply voltage transformer for measurement and the A-phase voltage transformer, the B-phase voltage transformer and the C-phase voltage transformer for power supply measurement, the accuracy of the transformer for measurement is ensured when the power supply is supplied. The power supply voltage transformer passes through the A-phase power supply, the B-phase power supply and the C-phase power supply, while the voltage transformer for the ring network cabinet passes through the A-phase power supply, the B-phase power supply, the C-phase power supply and the neutral line to measure the voltage, and the two do not interfere with each other, thus realizing the advantages of 6PT design and improving the accuracy of the measurement of the measurement device. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1The wiring schematic diagram of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit of the embodiment of the present application;

[0041] Figure 2 The right view sectional view of the cable plug of the voltage transformer of the independent power supply of the embodiment of the present application;

[0042] Figure 3 The front view sectional view of the cable plug of the voltage transformer of the independent power supply of the embodiment of the present application;

[0043] Figure 4 The top view sectional view of the cable plug of the voltage transformer of the independent power supply of the embodiment of the present application;

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

[0045] In the figure: 1, A-phase iron core; 2, B-phase iron core; 3, C-phase iron core; 4, A-phase primary coil; 5, B-phase primary coil; 6, C-phase primary coil; 7, O-phase iron core; 8, O-phase primary coil; 9, independent voltage iron core; 10, primary coil of power supply voltage transformer; 11, A-phase fuse; 12, B-phase fuse; 13, C-phase fuse; 14, O-phase terminal post; 15, N-phase terminal post; 16, A-phase connecting wire; 17, B-phase connecting wire; 18, C-phase connecting wire; 19, O-phase connecting wire; 20, N-phase connecting wire; 21, independent metering B-phase connecting wire; 22, independent metering C-phase connecting wire. DETAILED DESCRIPTION

[0046] In order to make the objects and advantages of the present application clearer, the present application will be further described below in conjunction with embodiments. It should be understood that the specific embodiments described herein merely serve the purpose of explaining the present application and are not used to limit the present application.

[0047] The preferred embodiments of the present application will be described below with reference to the drawings. It should be understood by those skilled in the art that the embodiments are merely used to explain the technical principles of the present application and are not used to limit the protection scope of the present application.

[0048] It should be noted that, in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating the direction or position relationship are based on the direction or position relationship shown in the drawings, which is merely for the convenience of description and is not used to 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 on the present application.

[0049] Moreover, it needs to be explained that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] Please refer to Figure 1 As shown in the figure, it is the wiring principle diagram of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit of the embodiment of the present application; the embodiment of the present application is a distribution network accurate metering system based on three-phase voltage transformer, comprising:

[0051] The distribution network (not shown in the figure) comprises a number of ring network cabinets for distributing power;

[0052] The temperature control unit (not shown in the figure) is used for temperature and humidity adjustment control inside the ring network cabinet;

[0053] The power grid monitoring unit is arranged in the ring network cabinet;

[0054] The harmonic elimination unit is arranged in the ring network cabinet;

[0055] The power consumption metering unit is arranged in the ring network cabinet;

[0056] The communication unit (not shown in the figure) is used to transmit the electric signal detected by the power grid monitoring unit;

[0057] The data acquisition unit (not shown in the figure) is connected with the communication unit, and is used to filter and amplify the electric signal to remove noise and interference, and calculate and store the electric energy related parameters according to the processed signal, the electric energy related parameters including voltage, current, power and ring network cabinet load;

[0058] The analysis unit (not shown in the figure) is connected with 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 respectively, and is used to determine whether the operation condition of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is qualified based on the power consumption fluctuation factor and the expected power consumption frequency, and when it is determined that the operation condition of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is unqualified, the corresponding alarm information is determined based on the factor difference amount;

[0059] The alarm unit (not shown in the figure) is connected with the analysis unit, and is used to send the 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 failure caused by low temperature, high temperature, and the occurrence of creeping and flashover accidents caused by dampness or condensation. The WHD48 temperature and humidity controller is installed in a panel embedded manner. First, a square slot hole of a specified size is made on the disc surface of the cabinet body, the device is embedded in the slot hole after the bracket is removed, and then the bracket is pushed into the clamping groove and locked.

[0061] Please continue to refer to Figure 1 As shown in the figure, it is a wiring principle diagram of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit of the embodiment of the present application; the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit of the present application are arranged in the ring network cabinet.

[0062] The power grid monitoring unit is used to measure power grid power, and includes an A-phase voltage transformer connected with an A-phase power supply, a B-phase voltage transformer connected with a B-phase power supply and a C-phase voltage transformer connected with a C-phase power supply.

[0063] The harmonic elimination unit includes an O-phase voltage transformer connected in series with the neutral point to dampen and eliminate ferroresonance.

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

[0065] Figure 1 In the figure, JB1 is a primary coil 10 of the power supply voltage transformer, JB2 is a secondary coil of the power supply voltage transformer, A is an A-phase power supply, B is a B-phase power supply, C is a C-phase power supply, O and o are both ground wires, N and n are both neutral wires, A1 is a primary coil of the A-phase voltage transformer, B1 is a primary coil of the B-phase voltage transformer, C1 is a primary coil of the C-phase voltage transformer, 1a is a first secondary coil of the A-phase voltage transformer, 2a is a second secondary coil of the A-phase voltage transformer, da is a third secondary coil of the A-phase voltage transformer, 1b is a first secondary coil of the B-phase voltage transformer, 2b is a second secondary coil of the B-phase voltage transformer, dn1 is a third secondary coil of the B-phase voltage transformer, 1c is a first secondary coil of the C-phase voltage transformer, 2c is a second secondary coil of the C-phase voltage transformer, dn2 is a third secondary coil of the C-phase voltage transformer, N1 is a primary coil of the O-phase voltage transformer, n2 is a first secondary coil of the O-phase voltage transformer, and n3 is a second secondary coil of the O-phase voltage transformer.

[0066] 1a, 1b and 1c are used to measure voltage values between respective phase power supplies, so as to detect voltage stability between the respective phase power supplies. 2a, 2b and 2c are used to output power supply for the ring network cabinet, N1 and n2 are used to eliminate resonance, and da, dn1, dn2 and n3 are connected in a loop, and used for ground protection.

[0067] jb2 is used to measure the power consumption of external power terminals;

[0068] The power supply voltage transformer of the electricity metering unit is powered by three phases ABC and is used to provide power to external power users.

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

[0070] The current transformers are cast together with epoxy resin to form a single unit, meeting the requirement of a small size for the ring main unit. By separating the current transformers for power supply and metering, ferroresonance is reliably suppressed, improving system stability.

[0071] When the core flux density is designed to be low, the current transformer operates in the linear region. When the power supply and metering current transformers are not separated, the current transformer simultaneously withstands various complex operating conditions and interferences, easily entering saturation and creating conditions for ferroresonance. After separating the power supply and metering current transformers, their loads are independent and clearly defined, avoiding mutual interference and influence, and reliably suppressing ferroresonance.

[0072] Please refer to the following documents separately. Figure 2 , Figure 3 as well as Figure 4 The figures shown are, respectively, a right-view cross-sectional view, a front-view cross-sectional view, and a top-view cross-sectional view of the cable plug of the voltage transformer of the independent power supply in an embodiment of the present invention.

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

[0074] Phase A primary coil 4 is used to receive the voltage signal from the Phase A power supply.

[0075] Phase A core 1 is connected to the primary coil 4 of phase A to receive the voltage signal transmitted by the primary coil 4 of phase A and transmit it to the secondary coil (not shown in the figure) of phase A.

[0076] A-phase fuse 11 is connected to the terminals of the A-phase primary coil 4 and is used to blow when the current exceeds the rated value, thereby cutting off the circuit and protecting the A-phase primary coil 4 and the A-phase core 1 from overcurrent damage.

[0077] A connecting wire 16 is connected to the A-phase iron core 1 and the A-phase secondary coil respectively to provide electrical connection and ensure signal transmission.

[0078] The B-phase voltage transformer includes:

[0079] Phase B primary coil 5 is used to receive the voltage signal from the Phase B power supply.

[0080] B phase core 2, which is connected with the B phase primary coil 5, receives the voltage signal transmitted by the B phase primary coil 5 and transmits it to the side of the B phase secondary coil (not shown in the figure);

[0081] B phase fuse 12, which is connected with the terminal of the B phase primary coil 5, melts and cuts off the circuit when the current exceeds the rated value, so as to protect the B phase primary coil 5 and the B phase core 2 from overcurrent damage.

[0082] B phase connecting line 17, which is connected with the B phase core 2 and the B phase secondary coil respectively, provides electrical connection and ensures signal transmission.

[0083] The C phase voltage transformer comprises:

[0084] C phase primary coil 6, which receives the voltage signal of the C phase power supply;

[0085] C phase core 3, which is connected with the C phase primary coil 6, receives the voltage signal transmitted by the C phase primary coil 6 and transmits it to the side of the C phase secondary coil (not shown in the figure);

[0086] C phase fuse 13, which is connected with the terminal of the C phase primary coil 6, melts and cuts off the circuit when the current exceeds the rated value, so as to protect the C phase primary coil 6 and the C phase core 3 from overcurrent damage.

[0087] C phase connecting line 18, which is connected with the C phase core 3 and the C phase secondary coil respectively, provides electrical connection and ensures signal transmission.

[0088] The power supply voltage transformer comprises:

[0089] Primary coil 10 of the power supply voltage transformer, which receives the voltage signal between the ABC three-phase power supply;

[0090] Independent voltage core 9, which receives the voltage signal transmitted by the primary coil 10 of the power supply voltage transformer and transmits it to the side of the independent power supply secondary coil (not shown in the figure).

[0091] Independent metering B phase connecting line 21, which is connected with the B phase power supply and one side terminal of the primary coil 10 of the power supply voltage transformer respectively;

[0092] Independent metering C phase connecting line 22, which is connected with the C phase power supply and the side terminal of the primary coil 10 of the power supply voltage transformer away from the B phase power supply respectively.

[0093] The O phase voltage transformer comprises:

[0094] O phase primary coil 8, which receives the neutral line voltage signal;

[0095] O-phase core 7, which 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) side;

[0096] O-phase connecting line 19, which is used to connect the O-phase primary coil 8 and the O-phase secondary coil side circuit;

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

[0098] N-phase terminal post 15, which is connected with the ground, used to ensure firm neutral grounding;

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

[0100] Specifically, the cable plug and the connector are well sealed, the voltage transformer is internally poured with epoxy resin, and the outside is sprayed with conductive paint for grounding. The voltage transformer is convenient to install and has high use safety, and is used in ring network cabinets and gas-filled cabinets.

[0101] Please refer to Figure 5 The power consumption metering unit can include a first power voltage transformer connected with the A-phase power supply and the B-phase power supply respectively and used to meter the power consumption of the power consumption end, and a second power voltage transformer connected with the B-phase power supply and the C-phase power supply respectively and used to meter the power consumption of the power consumption end.

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

[0103] 1a, 1b, and 1c are used to measure the voltage values between the power supplies of the respective phases to detect the voltage stability between the power supplies of the respective phases. 2a, 2b, and 2c are used to output power for the ring main unit, N1 and n2 are used to eliminate resonance, da, db, dc, and n3 are connected end to end and used for ground 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, which can be a warning light used to emit light when any power supply of the ABC three-phase power supply fails, or can be externally connected to a microcomputer coordination device. Those skilled in the art can understand that the indication reminding function can be realized when any power supply of the ABC three-phase power supply fails, which is prior art and will not be described in detail.

[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 to meter the power consumption of the external power consumption end;

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

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

[0109] Based on the power consumption determined in each test period, a power consumption time domain curve in the current detection period is drawn, and the absolute value of the difference between the maximum value and the minimum value of the power consumption time domain curve is solved, which is recorded 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 operation status of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is 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 operation status of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is 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 operation status of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is unqualified, and the alarm unit is controlled to issue 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], and D0 is the average value of the power consumption of each pilot period obtained from historical data, with the unit being MWh.

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

[0115] The average value of each average peak value of each historical power consumption time domain curve is solved to obtain the expected power consumption anchor point;

[0116] The peak value variance of each peak value of each historical power consumption time domain curve is solved, and the positive and negative deviations of the expected power consumption anchor point are determined based on the peak value variance;

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

[0118] In this embodiment, optionally,

[0119] The peak value variance is compared with the first preset peak value variance and the second preset peak value variance;

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

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

[0122] If the peak value variance is greater than the second preset peak value variance, the deviation value of the positive and negative deviation of the expected electricity anchor point is adjusted to 1.29 times of the initial deviation value;

[0123] The first preset peak value variance is 0.09F0 2 , the second preset peak value variance is 0.25F0 2 , F0 is the average value of each peak value of each historical electricity consumption time domain curve, and the unit of the preset peak value variance is MWh 2 .

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

[0125] The expected electricity interval is the expected electricity anchor point plus and minus the deviation value;

[0126] If the expected electricity frequency is less than or equal to the preset expected electricity frequency, the corresponding alarm information is issued by the factor difference amount control alarm unit;

[0127] If the expected electricity frequency is greater than the preset expected electricity frequency, the first preset electricity fluctuation factor and the second preset electricity fluctuation factor are adjusted to the corresponding values based on the expected electricity frequency.

[0128] Based on the electricity fluctuation factor, it is determined whether the operation status of the power grid monitoring unit, the harmonic elimination unit and the electricity metering unit is qualified. The electricity fluctuation factor represents the electricity fluctuation of the electricity end. The electricity fluctuation of the electricity end is monitored to identify abnormal conditions in time. When the electricity fluctuation factor is greater than the second preset electricity fluctuation factor, it is determined that the operation status of the power grid monitoring unit, the harmonic elimination unit and the electricity metering unit is unqualified, and the corresponding alarm information is issued by the factor difference amount control alarm unit. When the electricity fluctuation factor is less than or equal to the second preset electricity fluctuation factor and greater than the first preset electricity fluctuation factor, it is impossible to determine the state of the current power grid monitoring unit, the harmonic elimination unit and the electricity metering unit only according to the electricity fluctuation. At this time, whether the operation status of the power grid monitoring unit, the harmonic elimination unit and the electricity metering unit is qualified is determined by combining the expected electricity frequency.

[0129] The expected electricity anchor point is determined, and the expected electricity interval is determined by combining the peak value variance. The expected electricity frequency further represents the electricity abnormality of the electricity end through analysis of historical data. When the expected electricity frequency is greater than the preset expected electricity frequency, it is represented that the electricity peak value situation of the electricity end conforms to the historical data rule, and the first preset electricity fluctuation factor and the second preset electricity fluctuation factor are further adjusted to lower the evaluation standard, and the specific situation of the electricity end is further determined according to the detection parameters. While capturing the abnormal conditions of the power grid monitoring unit, the harmonic elimination unit and the electricity metering unit in time, the detection and measurement accuracy for the distribution network is further improved.

[0130] The preset expected power consumption frequency P0 is selected in the interval [0.7M0, 0.8M0], and M0 is the average of the historical expected power consumption frequencies.

[0131] The analysis unit increases 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, wherein:

[0132] The increase range of the first preset power consumption fluctuation factor and the second preset power consumption fluctuation factor is 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 1.3P0, and the second frequency comparison threshold is 1.7P0.

[0138] Specifically, the analysis unit controls the alarm unit to issue 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 recorded 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 to lower the temperature inside the ring main unit to a corresponding value based on the factor difference amount;

[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 to issue corresponding alarm information based on the fluctuation tendency parameter;

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

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

[0144] The factor difference amount control alarm unit sends corresponding alarm information, and when the factor difference amount is less than or equal to the first preset factor difference amount, the performance of internal elements of the mutual inductor in the ring main unit changes due to the operation of the mutual inductor in the high-temperature environment, the magnetic core of the mutual inductor appears magnetic saturation phenomenon at high temperature, which causes the output signal of the mutual inductor to be distorted, thereby affecting the metering accuracy of the electric energy meter, causing the detected power consumption to be lower than the actual power consumption, and causing the power fluctuation factor to be larger. The internal temperature of the ring main unit is adjusted to ensure accurate metering.

[0145] Specifically, the analysis unit is configured to control the alarm unit to send corresponding alarm information based on the fluctuation tendency parameter, and the analysis unit comprises:

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

[0147] If the fluctuation tendency parameter is greater than the preset fluctuation tendency parameter, the factor difference amount control temperature control unit lowers 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 time deviation parameter control alarm unit sends corresponding alarm information.

[0149] The preset fluctuation tendency parameter is 0.

[0150] When 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 specific conditions of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit are further analyzed in combination with the fluctuation tendency parameter. The fluctuation tendency parameter represents the change of the abnormal power consumption of the power consumption end. When the fluctuation tendency parameter is greater than the preset fluctuation tendency parameter, the expected power consumption frequency gradually increases. In the case that the detection data obtained by the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit gradually stabilizes, the power fluctuation factor is large, it is determined that the output signal of the mutual inductor is distorted, which affects the metering accuracy, and the current detection accuracy gradually stabilizes. At this time, the temperature control unit slightly adjusts the internal temperature of the ring main unit to further ensure the stable metering of power consumption.

[0151] Specifically, the analysis unit is configured to control the alarm unit to send corresponding alarm information based on the time deviation parameter, and the analysis unit comprises:

[0152] The interval average value of the time interval at which each peak value of the current power consumption time domain curve is in the expected power consumption interval is solved;

[0153] A time deviation parameter is obtained by taking the ratio of a time interval between a time node of a peak value in the expected power consumption interval in the power consumption time domain curve closest to the current time node and a time node of a last peak value in the expected power consumption interval and an interval average value.

[0154] If the time deviation parameter is less than or equal to a preset time deviation parameter, the control alarm unit is controlled to issue alarm information for voltage transformer insulation abnormality.

[0155] If the time deviation parameter is greater than the preset time deviation parameter, the control alarm unit is controlled to issue alarm information for communication module abnormality.

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

[0157] In the case of obvious abnormal deviation of the power fluctuation factor, the control alarm unit is controlled to issue corresponding alarm information based on the time deviation parameter. At this time, the power consumption is too low, resulting in a too large power 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 the three-phase voltage transformer has failed, for example, winding short circuit, insulation damage, etc., resulting in inaccurate voltage signals output by the three-phase voltage transformer, and large errors in processing of power parameters. When the time deviation parameter is greater than the preset time deviation parameter, the abnormal duration is too long. Due to the communication module failure, the data transmission between the metering system and the external device is 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. The abnormal situation is timely alarmed to ensure that the power consumption end can be metered in various complex environments.

[0158] The temperature control unit is controlled to lower the temperature inside the ring main unit to a corresponding value based on the factor difference amount, wherein:

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

[0160] In the embodiment, optionally,

[0161] The factor difference amount is compared with a first difference amount comparison threshold and a second difference amount comparison threshold.

[0162] If the factor difference amount is less than or equal to the first difference amount comparison threshold, the temperature inside the ring main unit is lowered 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, the temperature inside the ring main unit is lowered to 0.84 times the initial temperature.

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

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

[0166] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

[0167] The above description is only the preferred embodiments of the present application and is not intended to limit the present application; for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A precise metering system for distribution networks based on three-phase voltage transformers, characterized in that, include: A power distribution network, which includes several ring main units used to distribute electricity; Temperature control unit, which is used for temperature and humidity regulation and control inside the ring main unit; A power grid monitoring unit, used to measure the power grid energy, includes an A-phase voltage transformer connected to the A-phase power source, a B-phase voltage transformer connected to the B-phase power source, and a C-phase voltage transformer connected to the C-phase power source. The harmonic suppression unit includes a phase-0 voltage transformer connected in series with the neutral point to act as a damper to eliminate ferromagnetic resonance. The electricity metering unit includes a power supply voltage transformer that is connected to the A-phase power supply, the B-phase power supply and the C-phase power supply respectively, for measuring the electricity consumption at the electricity consumption end. A communication unit, used to transmit electrical signals detected by the power grid monitoring unit; The data acquisition unit, which is connected to the communication unit, is used to filter and amplify the electrical signal to remove noise and interference, and to calculate and store the power-related parameters based on the processed signal. The power-related parameters include voltage, current, power and ring main unit load. An analysis unit, which is connected to the temperature control unit, the power grid monitoring unit, the harmonic elimination unit, the electricity metering unit, the communication unit, and the data acquisition unit, is used to determine whether the operating status of the power grid monitoring unit, the harmonic elimination unit, and the electricity metering unit is qualified based on the electricity fluctuation factor and the expected electricity frequency, and to issue corresponding alarm information based on the factor difference when the operating status of the power grid monitoring unit, the harmonic elimination unit, and the electricity metering unit is determined to be unqualified. An alarm unit, which is connected to the analysis unit, is used to issue corresponding alarm information based on the judgment result of the analysis unit; The analysis unit is used to determine whether the operation status of the power grid monitoring unit, harmonic suppression unit, and electricity metering unit is qualified based on the electricity consumption fluctuation factor, including: The electricity consumption at the power consumption end is determined periodically based on the parameters acquired by the data acquisition unit. Based on the electricity consumption determined in each pilot period, the electricity consumption time-domain curve for the current detection period is plotted, and the absolute value of the difference between the maximum and minimum values ​​in the electricity consumption time-domain curve is denoted as the electricity fluctuation factor. If the power consumption fluctuation factor is less than or equal to the first preset power consumption fluctuation factor, the operation status of the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit is determined to be qualified, and the power grid monitoring unit, the harmonic elimination unit, and the power consumption metering unit are controlled to continue to operate using the current operating parameters. If the electricity fluctuation factor is less than or equal to the second preset electricity fluctuation factor and greater than the first preset electricity fluctuation factor, then the operation status of the power grid monitoring unit, the harmonic elimination unit and the electricity metering unit is determined based on the expected electricity frequency. If the power consumption fluctuation factor is greater than the second preset power consumption fluctuation factor, the operation status of the power grid monitoring unit, the harmonic elimination unit and the power consumption metering unit is determined to be unqualified, and the alarm unit is controlled to issue corresponding alarm information based on the factor difference. The analysis unit is used to determine whether the operation status of the power grid monitoring unit, harmonic suppression unit, and electricity metering unit is qualified based on the expected electricity consumption frequency, including: The average value of each peak value of each historical electricity consumption time-domain curve is calculated to obtain the expected electricity consumption anchor point; Solve for the peak variance of each peak value in the time-domain curve of each historical electricity consumption, and determine the positive or negative deviation of the expected electricity consumption anchor point based on the peak variance; The peak variance is proportional to the increase in the deviation value of the positive and negative deviations of the expected power anchor point; The expected electricity consumption frequency is the number of peak values ​​in the current electricity consumption time-domain curve that fall within the expected electricity consumption range. The expected electricity consumption range is the expected electricity consumption anchor point plus or minus the deviation value; If the expected electricity consumption frequency is less than or equal to the preset expected electricity consumption frequency, the alarm unit will issue the corresponding alarm information based on the factor difference. If the expected electricity consumption frequency is greater than the preset expected electricity consumption frequency, then the first preset electricity consumption fluctuation factor and the second preset electricity consumption fluctuation factor will be increased to the corresponding values ​​based on the expected electricity consumption frequency.

2. The distribution network precision metering system based on three-phase voltage transformers according to claim 1, characterized in that, The phase A voltage transformer includes: The primary coil of phase A is used to receive the voltage signal from the phase A power supply. The A-phase iron core is connected to the A-phase primary coil to receive the voltage signal transmitted by the A-phase primary coil and transmit it to the A-phase secondary coil side. The A-phase fuse is connected to the terminals of the A-phase primary coil and is used to blow when the current exceeds the rated value, thereby cutting off the circuit and protecting the A-phase primary coil and A-phase core from overcurrent damage. The A-phase connection is connected to both the A-phase iron core and the A-phase secondary coil to provide electrical connection and ensure signal transmission.

3. The distribution network precision metering system based on three-phase voltage transformers according to claim 2, characterized in that, The B-phase voltage transformer includes: The primary coil of phase B is used to receive the voltage signal from the phase B power supply. The B-phase iron core is connected to the B-phase primary coil to receive the voltage signal transmitted by the B-phase primary coil and transmit it to the B-phase secondary coil side. The B-phase fuse is connected to the terminals of the B-phase primary coil and is used to blow when the current exceeds the rated value, thereby cutting off the circuit and protecting the B-phase primary coil and the B-phase core. The B-phase connection is connected to the B-phase iron core and the B-phase secondary coil respectively to provide electrical connection.

4. The distribution network precision metering system based on three-phase voltage transformers according to claim 3, characterized in that, The C-phase voltage transformer includes: The primary coil of phase C is used to receive the voltage signal from the phase C power supply. The C-phase iron core is connected to the C-phase primary coil to receive the 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 terminals of the C-phase primary coil. It is used to blow when the current exceeds the rated value, cutting off the circuit and protecting the C-phase primary coil and C-phase core from overcurrent damage. The C-phase connection wire is connected to the C-phase core and the C-phase secondary coil respectively to provide electrical connection and ensure signal transmission.

5. The distribution network precision metering system based on three-phase voltage transformers according to claim 4, characterized in that, The power supply voltage transformer includes: The primary coil of the power supply voltage transformer is used to receive the voltage signals between the three phases A, B, and C of the power supply. An 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 precision metering system based on three-phase voltage transformers according to claim 5, characterized in that, The power supply voltage transformer also includes: The first power supply voltage transformer 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 at 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 and C-phase power supplies in order to measure the power consumption at the power consumption end.

7. The distribution network precision metering system based on three-phase voltage transformers according to claim 6, characterized in that, The O-phase voltage transformer includes: The primary coil of phase O is used to receive the neutral line voltage signal; The O-phase 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. The O-connection wire 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 and ensure signal transmission.

8. The distribution network precision metering system based on three-phase voltage transformers according to claim 7, characterized in that, The N-phase terminal is connected to the ground to ensure a reliable neutral point grounding. The N-connection wire is connected to the terminal of the primary coil of phase O to transmit unbalanced current.

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

10. The distribution network precision metering system based on three-phase voltage transformers according to claim 9, characterized in that, Each power supply voltage transformer and each phase voltage transformer used for metering has its own independent coil and wiring; each transformer is grounded by spraying conductive paint on its exterior.

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