Electric energy meter

Abstract

The embodiment of the invention provides an electric energy meter. A meter reading circuit in the electric energy meter is used for determining electricity consumption and active power according to a current signal at the other end of a current acquisition circuit and a voltage signal at the other end of a voltage acquisition circuit; the detection circuit is used for determining whether the electric energy meter loses voltage based on the voltage signal; in addition, the detection circuit is also used for determining whether the electric energy meter loses current or has wrong wiring based on the current signal. And finally, the detection circuit is used for determining whether the electricity consumption is accurate according to the voltage signal, the current signal and the active power. The electric energy meter can automatically check whether abnormal conditions such as voltage loss, current loss, wiring errors and electricity consumption metering inaccuracy exist or not, and the efficiency of checking the abnormality of the electric energy meter is improved.

Description

Technical Field

[0001] This application relates to the field of electrical technology, and more particularly to an electricity meter. Background Technology

[0002] An electricity meter, also known as a kilowatt-hour meter, is an instrument specifically used to measure electrical energy consumption. With the widespread availability of electricity, almost every household is equipped with an electricity meter. These meters automatically measure a user's electricity consumption without requiring the power supplier to visit the household to check the meter. However, electricity meters can also malfunction, such as measuring errors.

[0003] In existing technologies, users need to actively check whether their electricity meters are malfunctioning, or they need to notify the power supplier to come and verify them, or the power supplier needs to actively check the user's electricity consumption.

[0004] However, this method of existing technology has low efficiency in detecting anomalies in electricity meters. Summary of the Invention

[0005] This application provides an electricity meter for automatically detecting whether the electricity meter is abnormal, thereby improving the efficiency of abnormality verification.

[0006] In a first aspect, embodiments of this application provide an electricity meter, including: a control circuit, a current acquisition circuit, a voltage acquisition circuit, a meter reading circuit, and a detection circuit; one end of the current acquisition circuit is connected to the power input line of the electricity meter through the control circuit, and the other end of the current acquisition circuit is connected to the meter reading circuit and the detection circuit; one end of the voltage acquisition circuit is connected to the power input line, and the other end of the voltage acquisition circuit is connected to the meter reading circuit and the detection circuit.

[0007] The meter reading circuit is used to determine the electricity consumption and active power based on the current signal at the other end of the current acquisition circuit and the voltage signal at the other end of the voltage acquisition circuit.

[0008] The detection circuit is used to determine whether the energy meter is undervoltage based on the voltage signal.

[0009] The detection circuit is also used to determine, based on the current signal, whether the energy meter is experiencing a current loss or a wiring error.

[0010] The detection circuit is also used to determine whether the power consumption is accurate based on the voltage signal, current signal, and active power.

[0011] In one possible implementation, the control circuit includes: a first relay, a second relay, and a first resistor, one end of the first resistor being connected to the power input line via the first relay, the other end of the first resistor being connected to the current acquisition circuit, one end of the second relay being connected to the power input line, and the other end of the second relay being connected to the current acquisition circuit.

[0012] The detection circuit is also used to control the first and second relays to close when the current value of the current signal is zero, to reacquire the current signal at the other end of the current acquisition circuit, and to determine that the energy meter is losing current when the current value of the reacquired current signal is zero.

[0013] In one possible implementation, the electricity meter is a single-phase electricity meter;

[0014] The detection circuit is further configured to calculate the metering error rate using the voltage signal, current signal, and active power as inputs to a first formula, and to determine whether the electricity consumption is accurate based on the metering error rate. The first formula is:

[0015]

[0016] In the above formula, Y1 is the metering error rate, P is the active power, U is the voltage of the voltage signal, and I is the current of the current signal. Power factor.

[0017] In one possible implementation, the energy meter is a three-phase energy meter with a three-phase four-wire connection;

[0018] The detection circuit is further configured to calculate the metering error rate using the voltage signal, current signal, and active power as inputs to a second formula, and to determine whether the electricity consumption is accurate based on the metering error rate. The second formula is:

[0019]

[0020] In the above formula, Y2 is the metering error rate, P represents the active power, U is the voltage of the voltage signal, and I is the current of the current signal. As for the power factor, A, B, and C are the three phases of the electricity meter.

[0021] In one possible implementation, the energy meter is a three-phase energy meter with a three-phase three-wire connection;

[0022] The power input line includes a current input line and a voltage input line. One end of the current acquisition circuit is connected to the current input line through the control circuit, and one end of the voltage acquisition circuit is connected to the voltage input line.

[0023] The detection circuit is further configured to use the voltage signal, current signal, and active power as inputs to a third formula to calculate the metering error rate, and based on the metering error rate, determine whether the electricity consumption is accurate. The third formula is:

[0024]

[0025] In the above formula, Y3 is the metering error rate, P represents the active power, A, B, and C are the three phases of the energy meter, U̇ represents the voltage phasor, and I is the line current value. Power factor.

[0026] In one possible implementation, the power input line includes a current input line and a voltage input line. The current input line is the secondary output line connected to a current transformer, and the voltage input line is the primary input line without the current transformer. The detection circuit further includes a third relay and a test transformer. One end of the third relay is connected to the voltage input line, and the other end of the third relay is connected to the detection circuit through the test transformer. The transformation ratio of the test transformer is the same as the rated transformation ratio of the current transformer.

[0027] The detection circuit is also used to control the third relay to close, obtain the secondary current flowing through the test transformer in the voltage input line and the current in the same phase current input line, and determine the transformation accuracy of the current transformer of that phase based on the secondary current and the current in the same phase current input line.

[0028] In one possible implementation, the electricity meter is a three-phase electricity meter with a registered capacity of 50 kilowatts or greater, or a three-phase four-wire connection with high supply and low metering.

[0029] The detection circuit is specifically used to input the secondary current and the current of the in-phase current input line into the fourth formula to calculate the current transformer error rate, and based on the current transformer error rate, determine the transformation accuracy of the current transformer for that phase. The fourth formula is:

[0030]

[0031] In the above formula, A, B, and C are the three phases of the energy meter, G is the error rate of the current transformer, I1 represents the secondary current value after the current in the voltage input line is transformed by the test transformer, and I0 represents the current value of the current input line in the same phase.

[0032] In one possible implementation, the power input line includes a current input line and a voltage input line, both of which are secondary output lines connected to the combined current transformer; the detection circuit further includes a third relay and a test transformer; one end of the third relay is connected to the voltage input line, and the other end of the third relay is connected to the detection circuit through the test transformer, the transformation ratio of the test transformer being the same as the rated transformation ratio of the combined current transformer; the energy meter is a three-phase energy meter with a high-voltage power supply and high-voltage metering three-phase three-wire connection system;

[0033] The detection circuit is specifically used to input the secondary current and the current of the in-phase current input line into the fifth formula to calculate the error rate of the combined current transformer, and based on the error rate of the combined current transformer, to determine the transformation accuracy of the combined current transformer for that phase. The fifth formula is:

[0034]

[0035] In the above formula, A, B, and C are the three phases of the electricity meter, G is the error rate, and AB and CB represent the linear values. The subscript 1 indicates the secondary current after the voltage input current flows through the test transformer and is transformed, while the subscript 0 indicates the current input current.

[0036] In one possible implementation, the electricity meter further includes a data misalignment indication component connected to the detection circuit;

[0037] The data misalignment indication component is configured to output indication information when at least one of the following conditions occurs:

[0038] The current in the current signal is less than zero;

[0039] The electricity meter is experiencing current or voltage loss;

[0040] The error rate of the electricity meter is greater than a preset error threshold.

[0041] In one possible implementation, the data misalignment indication component is specifically used for:

[0042] If the current in the current signal is less than zero, the power meter will output a wiring error message.

[0043] If the error rate exceeds a preset error threshold, an abnormal power consumption count prompt will be output.

[0044] The electricity meter provided in this application embodiment can verify whether the electricity meter is experiencing voltage or current loss, wiring errors, or inaccurate electricity consumption measurement through a detection circuit, thereby improving the efficiency of verifying electricity meter malfunctions. Attached Figure Description

[0045] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0046] Figure 1 This is a schematic diagram of the structure of a single-phase energy meter provided in an embodiment of this application;

[0047] Figure 2 This is a schematic diagram of the structure of an energy meter provided in an embodiment of this application;

[0048] Figure 3 A hardware schematic diagram of an energy meter without a current transformer provided for an embodiment of this application;

[0049] Figure 4 The hardware schematic diagram of the energy meter with current transformer provided in the embodiments of this application.

[0050] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0051] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0052] Traditionally, verifying the accuracy of electricity meter readings requires users to request meter calibration from the power company, or the power company's accounting staff to proactively contact users by phone when significant fluctuations in electricity consumption are detected. Only when users report discrepancies will power company personnel bring a calibration instrument to the site for verification. This process is time-consuming, easily leading to errors in electricity bills and unnecessary disputes. Furthermore, traditional calibration methods can only detect discrepancies in meter readings, but cannot determine the cause of the errors. Additionally, meter calibration requires staff to travel to the site for individual verification, resulting in low efficiency.

[0053] To address the aforementioned issues, this application provides an electricity meter that, in addition to performing normal electricity consumption measurement and meter reading, can also verify the accuracy of the meter reading data and automatically determine the reasons for inaccurate readings. This allows for the timely detection of meter anomalies, preventing electricity bill errors and disputes. Furthermore, it eliminates the need for staff to travel to the site for meter calibration, thus improving verification efficiency.

[0054] The electricity meter provided in this application can be a single-phase electricity meter or a three-phase electricity meter. Taking a single-phase electricity meter as an example... Figure 1 This is a schematic diagram of the structure of a single-phase energy meter provided in an embodiment of this application, as shown below. Figure 1 As shown, the electricity meter includes at least an LCD display 11, indicator lights 12 (which can be further subdivided into power, pulse, and signal indicator lights), a communication module 13, fixing screws 14, wire interfaces (specifically including live wire inlet 151, live wire outlet 152, neutral wire inlet 153, and neutral wire outlet 154), a test mutual inductance module 16, a button module (specifically including an up button 171 and a down button 172), and a meter reading data inaccuracy indicator light 18.

[0055] In addition to displaying normal meter reading data, the LCD screen 11 can also display the reasons for any abnormal meter reading data detected by the electricity meter.

[0056] Indicator light 12 can be used to indicate power, pulse flashing, and communication signal strength.

[0057] The communication module 13 can be replaced with a carrier communication module or a wireless communication module as needed.

[0058] The fixing screw 14 is used to fix the wire connected to the electricity meter.

[0059] The wire connector is used to insert wires.

[0060] The test transformer module 16 can be a current transformer. This test transformer module has a variety of matching transformation ratios to choose from. It can be replaced with the same transformation ratio as the metering current transformer that is matched with the energy meter. The accuracy of this test transformer module is not as high as that of the metering current transformer. It is only used to detect whether the metering current transformer is seriously inaccurate or damaged.

[0061] The button module is used to flip through pages on the LCD screen to find various types of meter reading data.

[0062] The meter reading data inaccuracy indicator light 18 is used to provide a prompt when meter reading data inaccuracy is detected. Under normal circumstances, this indicator light is not lit. When meter reading data is inaccurate, the meter reading data inaccuracy indicator light is constantly lit.

[0063] In this embodiment, the electricity meter can be divided into two types: one with a current transformer and one without. Depending on whether the electricity meter is equipped with a current transformer, the hardware circuit diagram of the electricity meter can be divided into a hardware schematic diagram without a transformer and a hardware schematic diagram with a transformer.

[0064] The electricity meter is divided into two independent systems: a meter reading circuit and a detection circuit. The data processing of the two systems is independent and does not affect each other. They only share one communication module for communication and an LCD screen for display. Figure 2 This is a schematic diagram of the structure of an electricity meter provided in an embodiment of this application, as shown below. Figure 2 As shown, it includes a control circuit 21, a current acquisition circuit 22, a voltage acquisition circuit 23, a meter reading circuit 24, and a detection circuit 25.

[0065] One end of the current acquisition circuit is connected to the power input line of the energy meter through the control circuit, and the other end of the current acquisition circuit is connected to the meter reading circuit and the detection circuit. One end of the voltage acquisition circuit is connected to the power input line, and the other end of the voltage acquisition circuit is connected to the meter reading circuit and the detection circuit.

[0066] In this embodiment, the meter reading circuit is used to determine the electricity consumption and active power based on the current signal from the other end of the current acquisition circuit and the voltage signal from the other end of the voltage acquisition circuit. The detection circuit can perform the following actions:

[0067] (1) Determine whether the energy meter is undervoltage based on the voltage signal;

[0068] (2) Based on the current signal, determine whether the energy meter is losing current or has an incorrect wiring;

[0069] (3) Determine whether the electricity consumption is accurate based on the voltage signal, current signal and active power.

[0070] In this embodiment, the meter reading circuit is used to process various data related to meter reading. The current acquisition circuit is used to acquire the current (i.e., current signal) of the power input line. The voltage acquisition circuit is used to acquire the terminal voltage (i.e., voltage signal) of the power input line.

[0071] The detection circuit is used to collect various detection signals and analyze them to determine whether the meter reading data is inaccurate and the reason for the inaccuracy.

[0072] The meter reading rule for electricity meters is to measure electricity consumption in real time. The detection circuit can sequentially check for problems that may cause inaccurate meter reading data, such as voltage loss, current loss, wiring errors, and metering chip inaccuracy, every 15 minutes. The inspection method is as follows:

[0073] First, the voltage signal from the voltage acquisition circuit is collected, and it is determined whether the voltage value is greater than a preset voltage threshold (e.g., 198 volts). If so, the energy meter is not undervoltage; otherwise, the energy meter is in an undervoltage state. Figure 1 The meter reading data inaccuracy indicator light is constantly on, and the power meter voltage loss is displayed on the LCD screen. Specifically, for the LCD screen, if the power meter is a single-phase power meter, the voltage loss is displayed directly, while if the power meter is a three-phase power meter, the voltage loss phase is displayed.

[0074] Secondly, the current signal at the back end of the current acquisition circuit is collected to determine if the current is less than zero. If the current value is less than zero, it indicates that there is a wiring error in the electricity meter. Additionally, in some embodiments, if the current value remains zero for an extended period, there may be a current loss.

[0075] Finally, the detection circuit can calculate the error rate based on the voltage signal, current signal, and active power. For example, based on the voltage value of the voltage signal, the current value of the current signal, and the power factor, a first power value is calculated, and the absolute value of the difference between the first power value and the active power is calculated. Then, the ratio of this absolute value to the active power is obtained as the error rate.

[0076] If the error rate is greater than the error rate threshold, it indicates that the electricity consumption calculation is inaccurate and there is a discrepancy.

[0077] Furthermore, in some embodiments, the control circuit may include a first relay, a second relay, and a first resistor. One end of the first resistor is connected to the power input line through the first relay, and the other end of the first resistor is connected to the current acquisition circuit. One end of the second relay is connected to the power input line, and the other end of the second relay is connected to the current acquisition circuit.

[0078] The detection circuit is also used to control the first and second relays to close when the current value of the current signal is zero, to reacquire the current signal at the other end of the current acquisition circuit, and to determine that the energy meter is losing current when the current value of the reacquired current signal is zero.

[0079] In this embodiment, when the current signal at the back end of the current acquisition circuit is zero, the first and second relays can be controlled to close, so that the control circuit is turned on. At this time, it is equivalent to having a load (first resistor). Then, the current acquisition circuit 22 continues to acquire the current signal. If the current value of the acquired current signal is still zero, it indicates that the energy meter is losing current.

[0080] When a wiring error or current loss is detected in the electricity meter, the meter reading inaccurate indicator light will remain on, and the LCD screen will display the wiring error or current loss (single-phase electricity meters will directly display current loss, and three-phase electricity meters will display the current loss phase).

[0081] In some embodiments, taking a single-phase electricity meter as an example, the incoming lines of a single-phase electricity meter consist of one live wire and one neutral wire, and the power supply incoming line is the primary power supply incoming line, with a single-phase voltage of 220 volts. For example, Figure 3 The hardware schematic diagram of the energy meter without current transformer provided in the embodiments of this application is as follows: Figure 3 As shown, it includes a first relay 301, a second relay 302, a first resistor 303, a current acquisition circuit 304, a voltage acquisition circuit 305, a metering chip 306, a key module 307, power, pulse, and communication indicator lights 308, a microcomputer module for meter reading 309, a communication module 310, a microcomputer module for detection 311, an LCD screen 312, and a meter reading data inaccuracy indicator light 313.

[0082] The meter reading circuit mainly includes a microcomputer module 309 for meter reading, a current acquisition circuit 304, a voltage acquisition circuit 305, a metering chip 306, a key module 307, a power supply, pulse, and communication indicator light 308, a communication module 310, and an LCD display screen 312.

[0083] The meter reading microcomputer module 309 is used to process various data related to meter reading. The current acquisition circuit 304 is used to acquire the current of the power supply line. The voltage acquisition circuit 305 is used to acquire the terminal voltage of the power supply line. The metering chip 306 measures the electricity consumption. The detection circuit mainly includes a detection microcomputer module 311, a first relay, a first resistor (220 ohms), a second relay, a meter reading data inaccuracy indicator, a communication module, and an LCD display.

[0084] The microcomputer module 311 for detection is used to collect various detection signals and analyze them to determine whether the meter reading data is inaccurate and the reason for the inaccuracy.

[0085] Specifically, the first relay 301 and the second relay 302 are used to detect whether the energy meter is losing current. The first relay is normally open under normal conditions, and the second relay is normally closed under normal conditions. The energizing control signal of the coils of the two relays is controlled by the detection microcomputer module 311. When it is necessary to test the energy meter for loss of current, the detection microcomputer module 311 controls the coils of the first relay 301 and the second relay 302 to be energized, the first relay switch is closed, and the second relay switch is opened, so that the front end of the current acquisition circuit 304 is connected to the first resistor 303 (e.g., a 220-ohm resistor) before being connected to the current acquisition circuit 304.

[0086] In this circuit, the detection microcomputer module 311 reacquires the current signal from the other end of the current acquisition circuit. If the reacquired current signal has a current value of zero, it determines that the energy meter is experiencing a current outage. In other words, if the current value output from the back end of the current acquisition circuit is still zero even when the line is under load, it proves that the energy meter is experiencing a current outage.

[0087] When a current loss is detected in the electricity meter, the meter reading inaccurate indicator light will remain on, and the LCD screen will display a message indicating a wiring error or current loss. Specifically, for single-phase electricity meters, the current loss will be displayed directly, while for three-phase electricity meters, the current loss phase will be displayed.

[0088] In this embodiment, the detection microcomputer module can automatically detect and determine whether the electricity meter is experiencing a loss of current, eliminating the need for staff to go to the site for verification. This also provides greater initiative and avoids problems such as electricity bill disputes caused by the delayed detection of electricity meter abnormalities.

[0089] Furthermore, for a single-phase energy meter, the detection microcomputer module 311 collects the voltage and current input data of the metering chip 306 (specifically including the current signal output by the current acquisition circuit and the voltage signal output by the voltage acquisition current circuit) and the output data of the metering chip 306 (e.g., active power), and calculates the metering error rate Y1 of the metering chip according to the following first formula:

[0090]

[0091] In the above formula, Y1 is the metering error rate, P is the active power, U is the voltage of the voltage signal, and I is the current of the current signal. Power factor.

[0092] When Y1 is not greater than 2%, the metering chip is within the allowable error range. If Y is greater than 2%, the metering chip is seriously inaccurate, the meter reading data inaccurate indicator light will be constantly on, and the metering chip inaccuracy rate Y1 will be displayed on the LCD screen to inform the user that the current electricity consumption metering is inaccurate.

[0093] In this embodiment, the error rate is calculated by a microcomputer module, which can proactively detect whether the electricity meter is inaccurate in its measurement of electricity consumption. This further avoids the situation where users cannot detect the abnormality of the electricity meter in time, which could lead to electricity bill disputes. At the same time, it eliminates the need for staff to go to the site for verification, thus improving detection efficiency.

[0094] Furthermore, in some embodiments, for three-phase energy meters with a registered capacity of less than 50 kilowatts and four-wire connections, the calculation formula used by the detection microcomputer module 311 when calculating the metering error rate Y2 of the metering chip differs, as shown in the second formula below:

[0095]

[0096] In the above formula, Y2 is the metering error rate, P represents the active power, U is the voltage of the voltage signal, and I is the current of the current signal. As for the power factor, A, B, and C are the three phases of the electricity meter.

[0097] In this embodiment, when Y2 is not greater than 2%, the metering chip is within the allowable error range. If Y2 is greater than 2%, the metering chip is seriously inaccurate, the meter reading data inaccurate indicator light will stay on, and the metering chip inaccuracy rate Y1 will be displayed on the LCD screen to inform the user that the current electricity consumption metering is inaccurate.

[0098] In this embodiment, by configuring the second formula, the error rate of three-phase energy meters with a three-phase four-wire connection and an installed capacity of less than 50 kilowatts can be calculated, and it can be determined whether there is a problem with inaccurate electricity consumption measurement. This allows the solution to be widely applied to different scenarios and improves its applicability.

[0099] In addition, in some embodiments, the electricity meter can also be an electricity meter equipped with a current transformer. The current meters equipped with current transformers are mainly divided into three-phase electricity meters with an installed capacity of 50 kilowatts and above, three-phase electricity meters with a high-voltage supply and high-voltage metering three-phase three-wire connection system (suitable for dedicated users with high-voltage supply and high-voltage metering), and three-phase electricity meters with a high-voltage supply and low-voltage metering three-phase four-wire connection system (suitable for dedicated users with high-voltage supply and low-voltage metering).

[0100] For example, Figure 4 The hardware schematic diagram of the energy meter with current transformer provided in the embodiments of this application is as follows: Figure 4 As shown, it includes a first relay 401, a second relay 402, a first resistor 403, a current acquisition circuit 404, a voltage acquisition circuit 405, a metering chip 406, a key module 407, power, pulse, and communication indicator lights 408, a microcomputer module for meter reading 409, a communication module 410, a microcomputer module for detection 411, an LCD screen 412, and a meter reading data inaccuracy indicator light 413.

[0101] With the above Figure 3 The meter reading circuit is the same as the energy meter without current transformer mentioned in the text. It mainly includes a microcomputer module 409 for meter reading, a current acquisition circuit 404, a voltage acquisition circuit 405, a metering chip 406, a key module 407, a power supply, pulse and communication indicator light 408, a communication module 410, and an LCD display screen 412.

[0102] in, Figure 4 Energy meters with current transformers and Figure 3 The difference between a power meter without a current transformer and a power meter is that: (1) the wiring method is different; (2) an additional test current transformer circuit is added.

[0103] Among them, for (1) changes in wiring method, the wiring method of three-phase energy meters with a capacity of 50 kilowatts or above and three-phase energy meters applicable to special users with high supply and low metering (the specifications and models of the energy meters are the same in these two cases) is three-phase four-wire system, the voltage input line is the primary input line with a phase voltage of 220 volts, and the current input line is the secondary output line with an external current transformer.

[0104] For three-phase energy meters with a three-phase three-wire connection system suitable for dedicated users of high-voltage power supply and high-voltage metering, both the voltage and current input lines need to be stepped down and reduced in current by a combined instrument transformer before being connected to the energy meter. Since the energy meter adopts a three-phase three-wire connection system, both the voltage and current input lines are secondary output lines of the combined instrument transformer.

[0105] For (2), an additional test mutual inductance circuit was added, originally Figure 3 The power input is specifically divided into current input and voltage input. One end of the current acquisition circuit is connected to the current input through the control circuit, and one end of the voltage acquisition circuit is connected to the voltage input.

[0106] In addition, such as Figure 4 As shown, the detection circuit also includes a third relay 414 and a test transformer 415. One end of the third relay 414 is connected to the voltage input line, and the other end of the third relay 414 is connected to the detection circuit through the test transformer 415.

[0107] The hardware principle of the meter reading circuit inside the energy meter with current transformer is basically the same as that of the energy meter without current transformer. Compared with the energy meter without current transformer, the detection circuit has an additional third relay 414 and test transformer 415. In addition, the third relay 414 is normally open, and the coil energization is controlled by the detection microcomputer module 411 in the detection circuit.

[0108] The verification principles for voltage and current loss, wiring errors, and inaccurate electricity consumption measurement by the metering chip in energy meters with current transformers are similar to those for energy meters without current transformers. The difference lies in:

[0109] When detecting voltage loss in energy meters equipped with current transformers, the phase voltage threshold for detection is 198 volts for three-phase energy meters with an installed capacity of 50 kilowatts or more and for dedicated users with high-voltage supply and low-voltage metering. For three-phase energy meters with high-voltage supply and high-voltage metering three-phase three-wire connection used by dedicated users, the phase voltage threshold for voltage loss detection is 99 volts.

[0110] In addition, in some embodiments, when the electricity consumption detected by the metering chip of an energy meter with a current transformer is inaccurate, the formula for calculating the error rate for three-phase energy meters with a registered capacity of 50 kW or more and for energy meters used by dedicated users with high-voltage supply and low-voltage metering is the same as the formula for three-phase four-wire connected energy meters (i.e., the second formula). However, for three-phase energy meters with high-voltage supply and high-voltage metering used by dedicated users with high-voltage supply and high-voltage metering, a third formula is required to calculate the metering error rate.

[0111]

[0112] In the above formula, Y3 is the metering error rate, P represents the active power, A, B, and C are the three phases of the energy meter, U̇ represents the voltage phasor, and I is the line current value. Power factor.

[0113] In this embodiment, by configuring the third formula, the metering error rate of a three-phase energy meter with a high-voltage power supply and metering three-phase three-wire connection system can be calculated to determine whether there is a problem with inaccurate electricity consumption metering. This allows the solution to be widely applied to different scenarios, improving its applicability.

[0114] Furthermore, in some embodiments, the energy meter with a current transformer, as mentioned above, is an additional energy meter compared to one without a current transformer. It adds a third relay 414 and a test transformer 415. Based on this, referring to the above... Figure 4 The detection microcomputer module 411 in the detection circuit can control the third relay 414 to close, obtain the secondary current flowing through the test transformer 415 in the voltage input line, as well as the current in the same phase current input line, and determine the current transformer transformation accuracy of the phase based on the secondary current and the current in the same phase current input line.

[0115] In addition, energy meters with current transformers are divided into three-phase energy meters with an installed capacity of 50 kilowatts and above, three-phase energy meters with a high-voltage supply and low-voltage metering system (suitable for dedicated users with high-voltage supply and low-voltage metering), and three-phase energy meters with a high-voltage supply and high-voltage metering system (suitable for rotary users with high-voltage supply and high-voltage metering). Due to the differences in wiring methods, the calculation formulas used to calculate the accuracy of current transformer transformation also differ.

[0116] In some embodiments, for three-phase energy meters with an installed capacity of 50 kW or more, and three-phase four-wire connection energy meters with high supply and low metering, the ratio of the current in the voltage input line (i.e., primary input line) of one phase to the current in the current input line (i.e., secondary output line after transformation by the current transformer) of that phase is the actual transformation ratio of the current transformer. The transformation ratio of the tested current transformer is the same as the rated transformation ratio (i.e., the transformation ratio value on the nameplate) of the external matching current transformer.

[0117] Therefore, if the secondary current value after the voltage input current value is transformed by the test transformer is equal to the current value of the current input in the same phase, it proves that the accuracy of the external current transformer is normal. If the secondary current value after the voltage input current value is transformed by the test transformer is not equal to the current value of the current input in the same phase, it proves that the accuracy of the external current transformer is abnormal.

[0118] The fourth formula for calculating the accuracy error rate G of the current transformer is as follows:

[0119]

[0120] In the above formula, A, B, and C represent the three phases of the energy meter, G is the current transformer error rate, I1 represents the secondary current value after the voltage input current is transformed by the test transformer, and I0 represents the current value of the current input current in the same phase. When G is not greater than 2%, it indicates that the accuracy of the current transformer in that phase is normal. If G is greater than 2%, it indicates that the current transformer transformation accuracy of that phase is inaccurate, the meter reading inaccurate indicator light will remain on, and the current transformer accuracy error rate G for that phase will be displayed on the LCD screen.

[0121] In some embodiments, in three-phase three-wire connection systems with high-voltage power supply and metering, since the voltage input line is also a secondary input line, once the energy meter detects a voltage loss, it indicates that the voltage coil of the combined current transformer is inaccurate. Therefore, only the metering accuracy of the current coil of the combined current transformer needs to be checked. The current coil of the combined current transformer transforms the AB line current and the CB line current. The current value measured by the current input line is the secondary current value of the AB line current and the CB line current. Therefore, the fifth formula for calculating the accuracy error rate G of the current transformer is as follows:

[0122]

[0123] In the above formula, A, B, and C represent the three phases of the three-phase energy meter, G represents the error rate of the combined current transformer, and AB and CB represent the line values. This represents the current phasor. Subscript 1 indicates the secondary current after the voltage input current flows through the test transformer, and subscript 0 indicates the current input current. When G is not greater than 2%, it proves that the accuracy of the combined transformer corresponding to the line current is normal. If G is greater than 2%, it proves that the accuracy of the combined transformer corresponding to the line current is inaccurate. The meter reading inaccurate indicator light will remain on, and the accuracy error rate G of the combined transformer for that line current will be displayed on the LCD screen.

[0124] In this embodiment, by configuring the fourth and fifth formulas, the error rate of three-phase energy meters with an installed capacity of 50 kilowatts or more, three-phase energy meters with a high-supply, low-metering, three-phase four-wire connection, and three-phase three-wire connection with a high-supply, high-metering system can be calculated, and it can be determined whether there is a problem with inaccurate electricity consumption measurement. This allows the solution to be widely applied to different scenarios and improves its applicability.

[0125] In some embodiments, the energy meter can output indication information through a data misalignment indication component, for example, when at least one of the following conditions is met: (1) the current of the current signal is less than zero; (2) the energy meter loses current or voltage; (3) the error rate of the energy meter is greater than a preset error threshold. Continuing to refer to the above... Figure 2 and Figure 3 The data inaccuracy indicator component can be a meter reading data inaccuracy indicator light and / or an LCD display.

[0126] Furthermore, in some embodiments, when the data inaccuracy indication component includes a liquid crystal display (LCD), if the current signal is less than zero, a wiring error message for the electricity meter can be output on the LCD. If the error rate exceeds a preset error threshold, an abnormal electricity consumption count message can be output on the LCD. This serves to alert the user and inform them of the cause of the current electricity meter malfunction.

[0127] In the above embodiments, the microcomputer module in the energy meter can be implemented using various STM32 microcontrollers, programmable logic controllers (PLCs), embedded systems, and other modules.

[0128] As described above, the electricity meter provided in this application can promptly detect abnormal meter readings, reducing unnecessary electricity bill disputes. Furthermore, staff no longer need to carry calibration equipment to verify each meter on-site, improving the efficiency of identifying inaccurate meter readings and reducing staff workload. Finally, staff can use this electricity meter to quickly identify users with abnormal meter readings and rapidly analyze the causes of metering inaccuracies.

[0129] In this application, the division of components or modules is merely a logical functional division. In actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0130] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0131] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit.

[0132] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. An electricity meter, characterized in that, include: Control circuit, current acquisition circuit, voltage acquisition circuit, meter reading circuit, and detection circuit; One end of the current acquisition circuit is connected to the power input line of the energy meter through the control circuit, and the other end of the current acquisition circuit is connected to the meter reading circuit and the detection circuit. One end of the voltage acquisition circuit is connected to the power input line, and the other end of the voltage acquisition circuit is connected to the meter reading circuit and the detection circuit. The meter reading circuit is used to determine the electricity consumption and active power based on the current signal at the other end of the current acquisition circuit and the voltage signal at the other end of the voltage acquisition circuit. The detection circuit is used to determine whether the energy meter is undervoltage based on the voltage signal. The detection circuit is also used to determine, based on the current signal, whether the energy meter is experiencing a current loss or a wiring error. The detection circuit is also used to determine whether the power consumption is accurate based on the voltage signal, current signal, and active power.

2. The electricity meter according to claim 1, characterized in that, The control circuit includes: a first relay, a second relay, and a first resistor. One end of the first resistor is connected to the power input line through the first relay, and the other end of the first resistor is connected to the current acquisition circuit. One end of the second relay is connected to the power input line, and the other end of the second relay is connected to the current acquisition circuit. The detection circuit is also used to control the first and second relays to close when the current value of the current signal is zero, to reacquire the current signal at the other end of the current acquisition circuit, and to determine that the energy meter is losing current when the current value of the reacquired current signal is zero.

3. The electricity meter according to claim 1 or 2, characterized in that, The electricity meter is a single-phase electricity meter; The detection circuit is further configured to calculate the metering error rate using the voltage signal, current signal, and active power as inputs to a first formula, and to determine whether the electricity consumption is accurate based on the metering error rate. The first formula is: In the above formula, Y1 is the metering error rate, P is the active power, U is the voltage of the voltage signal, and I is the current of the current signal. Power factor.

4. The electricity meter according to claim 1 or 2, characterized in that, The energy meter is a three-phase energy meter with a three-phase four-wire connection; The detection circuit is further configured to calculate the metering error rate using the voltage signal, current signal, and active power as inputs to a second formula, and to determine whether the electricity consumption is accurate based on the metering error rate. The second formula is: In the above formula, Y2 is the metering error rate, P represents the active power, U is the voltage of the voltage signal, and I is the current of the current signal. As for the power factor, A, B, and C are the three phases of the electricity meter.

5. The electricity meter according to claim 1, characterized in that, The energy meter is a three-phase energy meter with three-phase three-wire connection; The power input line includes a current input line and a voltage input line. One end of the current acquisition circuit is connected to the current input line through the control circuit, and one end of the voltage acquisition circuit is connected to the voltage input line. The detection circuit is further configured to use the voltage signal, current signal, and active power as inputs to a third formula to calculate the metering error rate, and based on the metering error rate, determine whether the electricity consumption is accurate. The third formula is: In the above formula, Y3 is the metering error rate, P represents the active power, A, B, and C are the three phases of the energy meter, U̇ represents the voltage phasor, and I is the line current value. Power factor.

6. The electricity meter according to claim 1, characterized in that, The power input includes a current input and a voltage input. The current input is the secondary output of a current transformer, and the voltage input is the primary input without the current transformer. The detection circuit also includes a third relay and a test transformer. One end of the third relay is connected to the voltage input, and the other end of the third relay is connected to the detection circuit through the test transformer. The transformation ratio of the test transformer is the same as the rated transformation ratio of the current transformer. The detection circuit is also used to control the third relay to close, obtain the secondary current flowing through the test transformer in the voltage input line and the current in the same phase current input line, and determine the transformation accuracy of the current transformer of that phase based on the secondary current and the current in the same phase current input line.

7. The electricity meter according to claim 6, characterized in that, The electricity meter is a three-phase electricity meter with a registered capacity of 50 kilowatts or greater, or a three-phase four-wire connection with high supply and low metering. The detection circuit is specifically used to input the secondary current and the current of the in-phase current input line into the fourth formula to calculate the current transformer error rate, and based on the current transformer error rate, determine the current transformer transformation accuracy of that phase. The fourth formula is: In the above formula, A, B, and C are the three phases of the energy meter, G is the error rate of the current transformer, I1 represents the secondary current value after the current in the voltage input line is transformed by the test transformer, and I0 represents the current value of the current input line in the same phase.

8. The electricity meter according to claim 6, characterized in that, The power input includes a current input and a voltage input, both of which are secondary outputs of the combined instrument transformer. The detection circuit also includes a third relay and a test transformer. One end of the third relay is connected to the voltage input, and the other end of the third relay is connected to the detection circuit through the test transformer. The transformation ratio of the test transformer is the same as the rated transformation ratio of the combined instrument transformer. The energy meter is a three-phase energy meter with a high-voltage power supply and high-voltage metering system. The detection circuit is specifically used to input the secondary current and the current of the in-phase current input line into the fifth formula to calculate the error rate of the combined current transformer, and based on the error rate of the combined current transformer, to determine the transformation accuracy of the combined current transformer for that phase. The fifth formula is: In the above formula, A, B, and C are the three phases of the electricity meter, G is the error rate, and AB and CB represent the linear values. The subscript 1 indicates the secondary current after the voltage input current flows through the test transformer and is transformed, while the subscript 0 indicates the current input current.

9. The electricity meter according to any one of claims 1, 2, 5-8, characterized in that, The energy meter also includes a data misalignment indicator component, which is connected to the detection circuit. The data misalignment indication component is configured to output indication information when at least one of the following conditions occurs: The current in the current signal is less than zero; The electricity meter is experiencing current or voltage loss; The error rate of the electricity meter is greater than a preset error threshold.

10. The electricity meter according to claim 9, characterized in that, The data misalignment indication component is specifically used for: If the current in the current signal is less than zero, the power meter will output a wiring error message. If the error rate exceeds a preset error threshold, an abnormal power consumption count prompt will be output.

Images