CN117233690A - Virtual load control circuit, electric energy meter on-site calibrator and calibration method thereof - Google Patents
Virtual load control circuit, electric energy meter on-site calibrator and calibration method thereof Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/04—Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/04—Housings; Supporting members; Arrangements of terminals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/28—Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/04—Voltage dividers
- G01R15/06—Voltage dividers having reactive components, e.g. capacitive transformer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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Abstract
The application relates to a virtual load control circuit, an electric energy meter on-site calibrator and a calibration method thereof. According to the scheme of the application, under the condition that the load of the electric energy meter to be detected is too small or even no load is generated, the main control unit controls the virtual load control circuit to generate virtual load current, the current transformer arranged in the electric energy meter field calibrator collects the virtual load current signal when the virtual load control circuit outputs the virtual load current signal to the live wire outlet end of the electric energy meter to be detected, and the current transformer is used for calculating the standard electric energy pulse signal, and the current clamp only needs to collect user load current without collecting user load current and virtual load current at the same time, so that the complexity and the potential danger of manual operation are avoided. In addition, because the virtual load current is not required to be collected through the current clamp, the space between the wiring terminal box of the electric energy meter to be detected and the electric energy meter field calibrator is not required to be large enough, and the connection mode between the wiring terminal box of the electric energy meter to be detected and the electric energy meter field calibrator is more flexible and various.
Description
Technical Field
The application relates to the field of instrument inspection and test instruments, in particular to a virtual load control circuit, an electric energy meter on-site calibrator and a calibration method thereof.
Background
The electric energy meter in the field operation has a plurality of faults such as out-of-tolerance electric energy errors and the like, and the metering accuracy of the electric energy meter is seriously influenced. Therefore, it is necessary to regularly check the electric energy meter on site.
When the electric energy meter is verified in the prior art, the live wire inlet wire and the zero wire inlet wire (outlet wire) of the electric energy meter to be tested are respectively connected to the live wire inlet wire and the zero wire inlet wire (outlet wire) of the electric energy meter to be tested in a crocodile clamp mode through 2 cables so as to acquire voltage signals, when the load of a user is too small or even no load is generated, a third cable is taken to generate virtual load current, the virtual load current is connected to the live wire outlet wire of the electric energy meter to be tested, the cables need to pass through a current clamp, meanwhile, the direction of passing through the current clamp needs to be noted, and after all the cables are connected, the user load current and the virtual load current generated by the virtual load circuit are acquired simultaneously through the current clamp.
Disclosure of Invention
The inventor finds that when the traditional electric energy meter is used for field verification, the crocodile clamp is used for connecting the electric energy meter to be detected, the crocodile clamp connecting mode has the problems of unreliable connection, easy falling off, short circuit, wire winding and damage, and potential safety hazard.
To solve the problem, the inventor firstly invents a buckle type electric energy meter field calibrator which is small in size, and is clamped right above a wiring terminal box of a tested electric energy meter in a buckle mode during field calibration, an elastic probe is arranged at the bottom of the calibrator, corresponding to the wiring terminal of the tested electric energy meter, and when the electric energy meter field calibrator is clamped on the tested electric energy meter, the elastic probe is compressed, so that connection between the electric energy meter field calibrator and the tested electric energy meter is realized, and a crocodile clip connection mode between the traditional electric energy meter field calibrator and the tested electric energy meter is replaced by connection of the elastic probe. However, the inventor finds that when the load of the user is measurable, the equipment is convenient to use and ensures the stability of connection, but when the load of the user is too small or even no load is applied, the space between the wiring terminal box of the electric energy meter to be detected and the electric energy meter field calibrator is small, the current of the virtual load circuit is inconvenient to collect by using the traditional current clamp, the operation difficulty is high, and the virtual load detection method is very difficult.
Aiming at the problem, the inventor improves the virtual load circuit, and collects current signals through a series current transformer at the output end of the virtual load control circuit, so that the application discloses the buckle type electric energy meter field calibrator with the built-in virtual load control circuit. The inventor finds that the method is also applicable to the traditional electric energy meter field calibrator in the using process.
Aiming at the situations that the space between a wiring terminal box of an electric energy meter to be detected and a buckle-type electric energy meter field calibrator is small, the current of a virtual load circuit is inconvenient to collect by using a current clamp, and an operator is required to monitor the magnitude of the user load current in real time in the process of collecting the user load current, and manually adjust the mode of taking a wire by a current clamp, the application provides a virtual load control circuit, an electric energy meter field calibrator and a calibration method thereof. The electric energy meter on-site calibrator collects a wire inlet end voltage signal, a user load current signal and a virtual load current signal generated by a virtual load control circuit of the electric energy meter, and calculates a standard electric energy pulse signal according to the signals.
According to a first aspect of the present application, there is provided a virtual load control circuit comprising:
an output end;
the transformer is positioned between the live wire inlet end and the zero wire inlet end of the electric energy meter to be detected or between the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected and is used for converting a first voltage between the live wire inlet end and the zero wire inlet end or between the live wire inlet end and the zero wire outlet end into a second voltage;
the power resistor is connected with the transformer and used for limiting the second voltage to generate virtual load current; and
and the switching device is positioned between the transformer and the live wire inlet end, between the transformer and the zero wire outlet end or the zero wire inlet end, between the transformer and the first end of the power resistor and between the second end of the power resistor and the output end, and is used for executing the operation of opening or opening the switch under the control of a control signal.
According to a second aspect of the present application, there is provided an electric energy meter on-site calibrator, comprising:
the virtual load control circuit according to the first aspect;
a main control unit;
the input end of the voltage sampling circuit is connected with the live wire inlet end and the zero wire inlet end or the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected, and the output end of the voltage sampling circuit is connected with the main control unit and is used for collecting the voltage of the inlet end of the electric energy meter to be detected and transmitting the voltage to the main control unit;
the current transformer is connected in series between the output end of the virtual load control circuit and the live wire outlet end of the detected electric energy meter and is used for collecting the virtual load current generated by the virtual load control circuit;
the first current sampling circuit is positioned between the current transformer and the main control unit and is used for collecting the virtual load current and transmitting the virtual load current to the main control unit;
the current clamp clamps the live wire outlet end of the detected electric energy meter and is used for detecting the user load current of the live wire outlet end; and
the input end of the second current sampling circuit is connected with the current clamp, and the output end of the second current sampling circuit is connected with the main control unit and is used for collecting the load current of the user and transmitting the load current to the main control unit;
the input end of the main control unit is connected with the voltage sampling circuit, the first current sampling circuit and the second current sampling circuit, the output end of the main control unit is connected with the virtual load control circuit, and the main control unit is used for sending a control signal to the virtual load control circuit under the condition that the user load current is lower than a preset threshold value, controlling the switching device to be in an on state and calculating a standard electric energy pulse signal according to the voltage of the incoming line end, the virtual load current and the user load current.
According to a third aspect of the present application, there is provided a verification method using the electric energy meter field verification instrument according to the second aspect, comprising:
receiving a user load current;
generating a dummy load current in response to the user load current being less than a preset current threshold;
collecting the voltage of a wire inlet end between a wire inlet end and a zero wire inlet end or between the wire inlet end and a zero wire outlet end of the electric energy meter to be detected; and
and calculating a standard electric energy pulse signal according to the incoming line terminal voltage, the virtual load current and the user load current.
According to the virtual load control circuit, the electric energy meter on-site calibration instrument and the calibration method thereof provided by the application, on one hand, the virtual load control circuit is arranged in the on-site calibration instrument, wiring and judgment of a virtual load test wire are omitted during on-site calibration of the traditional electric energy meter, and the space between the buckle-type electric energy meter on-site calibration instrument and the wiring terminal box of the electric energy meter to be tested is small during on-site calibration of the buckle-type electric energy meter, so that collection of the virtual load circuit current of the electric energy meter on-site calibration instrument is realized, the test is simpler, and the connection mode between the wiring terminal box of the electric energy meter to be tested and the electric energy meter on-site calibration instrument is more flexible and various. On the other hand, the main control unit automatically judges the size of the user load, under the condition that the load of the electric energy meter to be detected is too small or even no load, the main control unit controls the virtual load control circuit to generate virtual load current, a current transformer arranged in the electric energy meter field calibrator collects a virtual load current signal when the virtual load control circuit outputs the virtual load current signal to the live wire outlet end of the electric energy meter to be detected, the current transformer is used for calculating a standard electric energy pulse signal, the current clamp only needs to collect user load current, the user load current and the virtual load current do not need to be collected at the same time, the full-automatic setting of the main control unit simplifies the field operation flow, the complexity and potential danger of manual operation are avoided, and the labor cost is saved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it will be apparent that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings by those skilled in the art without departing from the scope of the claimed application.
Fig. 1 is a schematic structural diagram of an electric energy meter on-site calibrator connected with an electric energy meter to be tested according to an embodiment of the present application.
Fig. 2 is a schematic diagram of the virtual load control circuit in the electric energy meter on-site calibrator shown in fig. 1.
Fig. 3 is a flow chart of a verification method implemented in accordance with the electric energy meter field verifier shown in fig. 1.
Fig. 4 is another flow chart of a verification method implemented in accordance with the electric energy meter field verifier shown in fig. 1.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The inventor finds that when the traditional electric energy meter is used for field verification, the crocodile clamp is used for connecting the electric energy meter to be detected, the crocodile clamp connecting mode has the problems of unreliable connection, easy falling off, short circuit, wire winding and damage, and potential safety hazard.
To solve the problem, the inventor firstly invents a buckle type electric energy meter field calibrator which is small in size, and is clamped right above a wiring terminal box of a tested electric energy meter in a buckle mode during field calibration, an elastic probe is arranged at the bottom of the calibrator, corresponding to the wiring terminal of the tested electric energy meter, and when the electric energy meter field calibrator is clamped on the tested electric energy meter, the elastic probe is compressed, so that connection between the electric energy meter field calibrator and the tested electric energy meter is realized, and a crocodile clip connection mode between the traditional electric energy meter field calibrator and the tested electric energy meter is replaced by connection of the elastic probe. However, the inventor finds that when the load of the user is measurable, the equipment is convenient to use and ensures the stability of connection, but when the load of the user is too small or even no load is applied, the space between the wiring terminal box of the electric energy meter to be detected and the electric energy meter field calibrator is small, the current of the virtual load circuit is inconvenient to collect by using the traditional current clamp, the operation difficulty is high, and the virtual load detection method is very difficult.
Aiming at the problem, the inventor improves the virtual load circuit, and collects current signals through a series current transformer at the output end of the virtual load control circuit, so that the application discloses the buckle type electric energy meter field calibrator with the built-in virtual load control circuit. The inventor finds that the method is also applicable to the traditional electric energy meter field calibrator in the using process.
Fig. 1 is a schematic structural diagram of an electric energy meter on-site calibrator connected with an electric energy meter to be tested according to an embodiment of the present application. As shown in fig. 1, the electric energy meter to be tested includes a pulse output terminal, a live wire inlet terminal, a live wire outlet terminal, a neutral wire inlet terminal, and a neutral wire outlet terminal (denoted by "1#L in", "2#L out", "3#N in", and "4#N out" in fig. 1), respectively), and the pulse output terminal is configured to output an electric energy pulse signal.
As shown in fig. 1, the electric energy meter on-site calibrator includes: the device comprises a main control unit, a virtual load control circuit, a voltage sampling circuit, a current transformer, a first current sampling circuit, a current clamp and a second current sampling circuit.
As shown in fig. 1, the input end of the voltage sampling circuit is connected with the live wire inlet end and the zero wire inlet end of the electric energy meter to be detected or connected with the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected, and the output end of the voltage sampling circuit is connected with the main control unit and is used for collecting the voltage signal of the live wire inlet end of the electric energy meter to be detected and transmitting the voltage signal to the main control unit. The input end of the virtual load control circuit is connected with the live wire inlet end and the zero wire inlet end of the electric energy meter to be detected, or the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected, and is simultaneously connected with the main control unit, receives a switch control signal output by the main control unit, and a current transformer is connected in series between the output end of the virtual load control circuit and the live wire outlet end of the electric energy meter to be detected. The input end of the first current sampling circuit is connected with the current transformer, and the output end of the first current sampling circuit is connected with the main control unit and is used for transmitting virtual load current acquired by the current transformer to the main control unit. According to some embodiments, the first current sampling circuit may perform some processing, such as signal conditioning, a/D conversion, etc., on the virtual load current collected by the current transformer.
In fig. 1, a current clamp clamps the live wire outlet end of a detected electric energy meter, and is used for detecting the user load current of the live wire outlet end of the detected electric energy meter. And the input end of the second current sampling circuit is connected with the current clamp, and the output end of the second current sampling circuit is connected with the main control unit and is used for collecting the user load current input by the electric energy meter to be detected and transmitting the user load current to the main control unit.
The input end of the main control unit is connected with the voltage sampling circuit, the first current sampling circuit, the second current sampling circuit and the detected electric energy pulse signal output by the detected electric energy meter, and the output end of the main control unit is connected with the virtual load control circuit. The main control unit judges the load current sent by the second current sampling circuit on one side, if the load current of the user is not lower than a preset threshold value, the main control unit sends a control signal for closing the switch to the virtual load control circuit when the virtual load control circuit switch device is on at the moment, or does not execute any action to the virtual load control circuit when the switch device is off; if the user load current is lower than the preset threshold, the main control unit does not execute any action to the virtual load control circuit when the virtual load control circuit switching device is on, or sends a control signal for opening the switch to the virtual load control circuit when the switching device is off. On the other hand, under the condition that the virtual load control circuit generates virtual load current, the main control unit controls the voltage sampling circuit, the first current sampling circuit and the second current sampling circuit to synchronously sample, and standard electric energy pulse signals are calculated according to the acquired virtual load current signals, user load current signals and voltage signals; under the condition that the virtual load control circuit does not work, the main control unit controls the voltage sampling circuit and the second current sampling circuit to synchronously sample, and standard electric energy pulse signals are calculated according to the collected user load current signals and the collected voltage signals.
And then, the main control unit compares and calculates the standard electric energy pulse signal with the electric energy pulse signal output by the detected electric energy meter to obtain a comparison result. According to one embodiment, the master control unit may derive the instantaneous power error value in the form of a percentage, and store and display it. Therefore, the error of the detected electric energy meter is obtained by comparing the accumulated electric energy pulses of the detected electric energy meter and the electric energy meter field calibrator in the same time, and whether the detected electric energy meter is qualified is judged.
After the test is finished, the main control unit can automatically close the virtual load control circuit.
Fig. 2 is a schematic diagram of the virtual load control circuit in the electric energy meter on-site calibrator shown in fig. 1. As shown in fig. 2, the dummy load control circuit includes: transformer, power resistor and switching device.
The switching device is located at any one or more of the position between the transformer and the live wire inlet end (the position of the switch 1 in fig. 2), the position between the transformer and the neutral wire outlet end or the neutral wire inlet end (the position of the switch 2 in fig. 2), the position between the transformer and the first end of the power resistor (the position of the switch 3 in fig. 2), and the position between the second end of the power resistor and the output end of the virtual load control circuit (the position of the switch 4 in fig. 2), i.e. the switching device can be any one or more of the four switches in fig. 2, and the operation of opening the switch or breaking the switch is performed under the control of the control signal sent by the main control unit. Usually, the switch device defaults to be in an off state, i.e. all switches are in an off state, and when the virtual load control circuit needs to be started, the main control unit sends a control signal for starting the switches, and all the switches are in an on state.
According to one embodiment, a transformer may be located between the live and neutral inlet terminals of the electrical energy meter under test for converting a first voltage between the live and neutral inlet terminals to a second voltage. According to another embodiment, the transformer may also be located between the live and neutral inlet and outlet terminals of the electrical energy meter being tested, for converting a first voltage between the live and neutral inlet terminals to a second voltage. The power resistor is connected with the transformer and used for limiting the second voltage to generate virtual load current.
According to some embodiments, the transformer functions to reduce the voltage, and in fig. 2, the 1, 2-terminal and 1, 3-terminal turns ratios of the transformer are N: during the power-on process of the transformer, the voltages at the 1 and 2 ends are U (for example, about 220V generally), and the voltages at the 1 and 3 ends are U/N (about 220/NV generally), so that a small voltage is generated. After the small voltage is limited by a power resistor with a small resistance value, a virtual load current with a moderate size is generated, and the electric energy error test of the electric energy meter to be tested is facilitated.
Because the voltage and the current generating the virtual load are smaller, the power loss of the virtual load control circuit is also controlled to be minimum, and the whole volume and the weight of the virtual load control circuit are also small. In the field test, when the current electricity consumption of the user is small, even if the user does not consume electricity, the detected electric energy meter can be overlapped with a virtual load, so that the electric energy metered by the electric energy meter can be normally and accurately tested, and the problem that the current electricity consumption of the user is small and even the user cannot be tested correctly under the condition of no electricity consumption is solved.
On the basis of the electric energy meter on-site calibrator and the virtual load control circuit shown in fig. 1 and 2, according to one aspect of the present application, there is also provided a calibration method implemented by using the electric energy meter on-site calibrator. As shown in fig. 3, the method includes the following steps.
Step S301, receiving a user load current, judging the magnitude of the user load current and a preset current threshold, and executing steps S302 to S304 under the condition that the user load current is smaller than the preset current threshold; in the case where the user load current is not less than the preset current threshold, steps S305 to S307 are performed.
Step S302, generating a virtual load current in response to the user load current being smaller than a preset current threshold;
step S303, collecting the voltage of a wire inlet end between a wire inlet end and a zero wire inlet end or between the wire inlet end and a zero wire outlet end of the electric energy meter to be detected; and
and step S304, calculating a standard electric energy pulse signal according to the incoming line terminal voltage, the virtual load current and the user load current.
Step S305, in response to the user load current not being less than a preset current threshold, the switching device is in a closed state;
step S306, collecting the voltage of the wire inlet end between the wire inlet end and the zero wire inlet end or between the wire inlet end and the zero wire outlet end of the electric energy meter to be detected; and
step S307, calculating a standard electric energy pulse signal according to the incoming line terminal voltage and the user load current.
According to some embodiments, the current clamp clamps the live wire outlet end of the detected electric energy meter, and detects the user load current of the live wire outlet end of the detected electric energy meter; the second current sampling circuit collects user load current input by the detected electric energy meter and transmits the user load current to the main control unit; the virtual load control circuit receives a switch control signal output by the main control unit and generates virtual load current under the condition of starting the switch; the current transformer collects virtual load current generated by the virtual load control circuit; the first current sampling circuit transmits the virtual load current acquired by the current transformer to the main control unit; the voltage sampling circuit of the electric energy meter field calibrator collects the incoming line end voltage signal of the electric energy meter to be tested and transmits the incoming line end voltage signal to the main control unit.
The main control unit judges the load current sent by the second current sampling circuit on one side, if the load current of the user is not lower than a preset threshold value, the main control unit sends a control signal for closing a switch to the virtual load control circuit when the virtual load control circuit switching device is on, or the main control unit does not execute any action to the virtual load control circuit when the switching device is off; if the user load current is lower than the preset threshold value, the main control unit does not execute any action to the virtual load control circuit when the virtual load control circuit switching device is on, or sends a control signal for opening the switch to the virtual load control circuit when the switching device is off. On the other hand, under the condition that the virtual load control circuit generates virtual load current, the main control unit controls the voltage sampling circuit, the first current sampling circuit and the second current sampling circuit to synchronously sample, and standard electric energy pulse signals are calculated according to the acquired virtual load current signals, user load current signals and voltage signals; under the condition that the virtual load control circuit does not work, the main control unit controls the voltage sampling circuit and the second current sampling circuit to synchronously sample, and standard electric energy pulse signals are calculated according to the collected user load current signals and the collected voltage signals.
On the basis of the electric energy meter on-site calibrator and the virtual load control circuit shown in fig. 1 and 2, according to another aspect of the present application, there is also provided a calibration method implemented by using the electric energy meter on-site calibrator, as shown in fig. 4. Compared to fig. 3, steps S401 to S407 of fig. 4 are the same as steps S301 to S307 of fig. 3, except that fig. 4 further includes the steps of:
step S408, receiving an electric energy pulse signal output by the detected electric energy meter; and
and S409, comparing the electric energy pulse signal with the standard electric energy pulse signal to obtain a comparison result.
And the main control unit compares and calculates the standard electric energy pulse signal with the electric energy pulse signal output by the detected electric energy meter to obtain a comparison result. According to one embodiment, the master control unit may derive the instantaneous power error value in the form of a percentage, and store and display it. Therefore, the error of the detected electric energy meter is obtained by comparing the accumulated electric energy pulses of the detected electric energy meter and the electric energy meter field calibrator in the same time, and whether the detected electric energy meter is qualified is judged.
According to the virtual load control circuit, the electric energy meter on-site calibration instrument and the calibration method thereof provided by the application, on one hand, the virtual load control circuit is arranged in the on-site calibration instrument, wiring and judgment of a virtual load test wire are omitted during on-site calibration of the traditional electric energy meter, and the space between the buckle-type electric energy meter on-site calibration instrument and the wiring terminal box of the electric energy meter to be tested is small during on-site calibration of the buckle-type electric energy meter, so that collection of the virtual load circuit current of the electric energy meter on-site calibration instrument is realized, the test is simpler, and the connection mode between the wiring terminal box of the electric energy meter to be tested and the electric energy meter on-site calibration instrument is more flexible and various. For example, the on-site calibrator for the buckle type electric energy meter is small in size, the on-site calibrator is clamped right above a wiring terminal box of the electric energy meter to be tested in a buckle mode, an elastic probe is arranged at the bottom of the calibrator corresponding to the wiring terminal box of the electric energy meter to be tested, and when the on-site calibrator is clamped on the electric energy meter to be tested, the elastic probe is compressed, so that the on-site calibrator for the electric energy meter is connected with the electric energy meter to be tested. The voltage loop of the electric energy meter to be detected is connected in parallel to the voltage loop of the electric energy meter on-site calibrator in an elastic probe connection mode, the user load current of the electric energy meter to be detected is connected to the electric energy meter on-site calibrator through a current clamp, and accumulated electric energy pulses of the electric energy meter to be detected and the electric energy meter on-site calibrator within the same time are compared, so that errors of the electric energy meter to be detected are obtained, and whether the electric energy meter to be detected is qualified is judged. The traditional electric energy meter field calibrator is connected with a live wire inlet wire and a zero wire inlet wire (outlet wire) of the electric energy meter to be tested in a crocodile clamp mode through 2 cables respectively, voltage signals are obtained, when user loads are too small or even no load is caused, the main control unit controls the virtual load control circuit to be started, the built-in current transformer completes collection of virtual load circuit current, and the step of manually clamping the live wire and the virtual load circuit line of the electric energy meter by using the current clamp is omitted. On the other hand, the main control unit automatically judges the size of the user load, under the condition that the load of the electric energy meter to be detected is too small or even no load, the main control unit controls the virtual load control circuit to generate virtual load current, a current transformer arranged in the electric energy meter field calibration instrument collects the virtual load current signal when the virtual load control circuit outputs the virtual load current signal to the live wire outlet end of the electric energy meter to be detected, the current transformer is used for calculating the standard electric energy pulse signal, the current clamp only needs to collect the user load current, the user load current and the virtual load current do not need to be collected at the same time, the full-automatic setting of the main control unit simplifies the field operation flow, avoids the complexity and potential danger of manual operation, and saves the labor cost.
The foregoing has outlined rather broadly the more detailed description of embodiments of the application in order that the detailed description of the principles and embodiments of the application may be implemented in conjunction with the detailed description of embodiments of the application that follows. Meanwhile, based on the idea of the present application, those skilled in the art can make changes or modifications on the specific embodiments and application scope of the present application, which belong to the protection scope of the present application. In view of the foregoing, this description should not be construed as limiting the application.
Claims (9)
1. A virtual load control circuit, comprising:
an output end;
the transformer is positioned between the live wire inlet end and the zero wire inlet end of the electric energy meter to be detected or between the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected and is used for converting a first voltage between the live wire inlet end and the zero wire inlet end or between the live wire inlet end and the zero wire outlet end into a second voltage;
the power resistor is connected with the transformer and used for limiting the second voltage to generate virtual load current; and
and the switching device is positioned between the transformer and the live wire inlet end, between the transformer and the zero wire outlet end or the zero wire inlet end, between the transformer and the first end of the power resistor and between the second end of the power resistor and the output end, and is used for executing the operation of opening or opening the switch under the control of a control signal.
2. The virtual load control circuit of claim 1 wherein the second voltage is less than the first voltage.
3. An electric energy meter field calibrator, comprising:
the virtual load control circuit of claim 1 or 2;
a main control unit;
the input end of the voltage sampling circuit is connected with the live wire inlet end and the zero wire inlet end or the live wire inlet end and the zero wire outlet end of the electric energy meter to be detected, and the output end of the voltage sampling circuit is connected with the main control unit and is used for collecting the voltage of the inlet end of the electric energy meter to be detected and transmitting the voltage to the main control unit;
the current transformer is connected in series between the output end of the virtual load control circuit and the live wire outlet end of the detected electric energy meter and is used for collecting the virtual load current generated by the virtual load control circuit;
the first current sampling circuit is positioned between the current transformer and the main control unit and is used for collecting the virtual load current and transmitting the virtual load current to the main control unit;
the current clamp clamps the live wire outlet end of the detected electric energy meter and is used for detecting the user load current of the live wire outlet end; and
the input end of the second current sampling circuit is connected with the current clamp, and the output end of the second current sampling circuit is connected with the main control unit and is used for collecting the load current of the user and transmitting the load current to the main control unit;
the input end of the main control unit is connected with the voltage sampling circuit, the first current sampling circuit and the second current sampling circuit, the output end of the main control unit is connected with the virtual load control circuit, and the main control unit is used for sending a control signal to the virtual load control circuit under the condition that the user load current is lower than a preset threshold value, controlling the switching device to be in an on state and calculating a standard electric energy pulse signal according to the voltage of the incoming line end, the virtual load current and the user load current.
4. The electric energy meter on-site calibrator according to claim 3, wherein the main control unit is configured to send a control signal to the virtual load control circuit to control the switching device to be in an off state when the user load current is not lower than a preset threshold, and calculate the standard electric energy pulse signal according to the incoming line terminal voltage and the user load current.
5. The power meter field calibrator of claim 3 or 4, wherein the master control unit is further configured to:
receiving an electric energy pulse signal output by the detected electric energy meter; and
comparing the electric energy pulse signal with the standard electric energy pulse signal.
6. The electric energy meter on-site calibrator according to claim 3 or 4, wherein the electric energy meter on-site calibrator is connected to a terminal of the electric energy meter under test via an elastic probe.
7. A verification method using the electric energy meter on-site verification instrument according to any one of claims 3 to 6, comprising:
receiving a user load current;
generating a dummy load current in response to the user load current being less than a preset current threshold;
collecting the voltage of a wire inlet end between a wire inlet end and a zero wire inlet end or between the wire inlet end and a zero wire outlet end of the electric energy meter to be detected; and
and calculating a standard electric energy pulse signal according to the incoming line terminal voltage, the virtual load current and the user load current.
8. The verification method of claim 7, further comprising:
and responding to the user load current not smaller than the preset current threshold value, so that the switching device is in a closed state, and calculating a standard electric energy pulse signal according to the incoming line terminal voltage and the user load current.
9. The verification method of claim 7 or 8, further comprising:
receiving an electric energy pulse signal output by the detected electric energy meter; and
and comparing the electric energy pulse signal with the standard electric energy pulse signal to obtain a comparison result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311188588.3A CN117233690A (en) | 2023-09-14 | 2023-09-14 | Virtual load control circuit, electric energy meter on-site calibrator and calibration method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311188588.3A CN117233690A (en) | 2023-09-14 | 2023-09-14 | Virtual load control circuit, electric energy meter on-site calibrator and calibration method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN117233690A true CN117233690A (en) | 2023-12-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311188588.3A Pending CN117233690A (en) | 2023-09-14 | 2023-09-14 | Virtual load control circuit, electric energy meter on-site calibrator and calibration method thereof |
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| Country | Link |
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| CN (1) | CN117233690A (en) |
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2023
- 2023-09-14 CN CN202311188588.3A patent/CN117233690A/en active Pending
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