A multifunctional durability test device for electric energy meters

Abstract

The present invention discloses a multifunctional durability test device for electric energy meters, comprising a program-controlled power source cabinet and a plurality of electric energy meter test components, wherein the program-controlled power source cabinet is respectively connected to each electric energy meter test component; the electric energy meter test component comprises an ICT current transformer, a PT transformer and a plurality of test stations; the input end of the ICT current transformer is connected to the current output end of the program-controlled power source cabinet, and the output end of the ICT current transformer is connected to each test station; the input end of the PT transformer is connected to the voltage output end of the program-controlled power source cabinet, and the output end of the PT transformer is connected to each test station. The multifunctional durability test device for electric energy meters provided by the present invention ensures that one device can output a variety of different current values ​​and voltage values ​​at the same time, meeting the test requirements of electric energy meters with different current values ​​and voltage values.

Description

Technical Field

[0001] The invention relates to electric energy meter testing, in particular to a multifunctional durability testing device for electric energy meters. Background Art

[0002] The specific requirements of the durability test are to place the instrument in a temperature test chamber, heat it to the upper temperature limit specified by the instrument, and keep it stable (generally for 2 hours). The instrument voltage circuit applies 1.1 times the nominal voltage (if there are multiple nominal voltages, take the highest nominal voltage), the current circuit passes the maximum current Imax, and the power factor is 1. If the instrument can measure active power and reactive power at the same time, the power factor is 0.866L. The test continues for 1000 hours under this test condition. After the test, the instrument is restored to the reference temperature and the instrument error is measured again; the inherent error before and after the test is compared, and the error offset does not exceed the specified limit. The application scenarios of the experimental device are mainly R&D testing and sample instrument durability aging testing.

[0003] The device for durability test must have high stability and high reliability. Since the test process needs to run continuously at Imax for 1000h, the device for durability test continuously records the error between the electric energy meter and the standard electric energy during the process. Therefore, the device for durability test needs to have long-term stability, reliability and safety. The device can meet the latest State Grid and Southern Grid similar electric energy meter type evaluation test requirements and be compatible with the current electric energy meter test requirements.

[0004] Since the existing electricity meter calibration device is designed to only meet short-term testing, the demand test can be completed in 24 hours at most. The design performance of the existing device is far from the 1000h operation requirement, so the durability test device needs to be redesigned.

[0005] The durability test is faced with the evaluation test of the electric energy meter types of different manufacturers, so there will be a demand for testing electric energy meters with different current values. The electric energy meter test device can only output one current and voltage at a time. When multiple current electric energy meter tests are carried out at the same time, another electric energy meter test can only be carried out after waiting for 1000 hours. Faced with electric energy meters with various voltage and current specifications, one or more durability test devices cannot meet the test requirements. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a multifunctional durability test device for an electric energy meter, thereby ensuring that one device can output a variety of different current values ​​and voltage values ​​at the same time, thereby meeting the test requirements of electric energy meters with different current values ​​and voltage values.

[0007] The object of the present invention is achieved by the following technical solutions: a multifunctional durability test device for electric energy meters, comprising a program-controlled power source cabinet and a plurality of electric energy meter test assemblies, wherein the program-controlled power source cabinet is respectively connected to each electric energy meter test assembly;

[0008] The electric energy meter test assembly includes an ICT current transformer, a PT transformer and multiple test stations; the input end of the ICT current transformer is connected to the current output end of the programmable power source cabinet, and the output end of the ICT current transformer is connected to each test station; the input end of the PT transformer is connected to the voltage output end of the programmable power source cabinet, and the output end of the PT transformer is connected to each test station.

[0009] Furthermore, each of the electric energy meter test components has n test stations, and each test station is provided with an electric energy meter to be tested, wherein the electric energy meter to be tested in the first test station is the leading meter, and the electric energy meters to be tested in other test stations are test meters.

[0010] Furthermore, the program-controlled power source cabinet is provided with a program-controlled power source and a standard electric energy meter; the program-controlled power source includes three signal generating channels, and the output signals of the signal generating channels are respectively transmitted to each electric energy meter test component after passing through the electric energy meter;

[0011] Each of the signal generation channels includes a direct digital synthesis signal source, a feedback compensation adjustment circuit, a current power amplifier, a current booster, a voltage power amplifier, a voltage booster, a standard current sampling module and a standard voltage sampling module; the direct digital synthesis signal source is used to generate an initial current signal and an initial voltage signal, the initial current signal passes through the current power amplifier and the current booster in sequence and then outputs the current signal to the outside, the standard current sampling module is used to sample the output current, obtain the current sampling signal and feed it back to the feedback compensation adjustment circuit; the initial voltage signal passes through the voltage power amplifier and the voltage booster and then outputs the signal to the outside, the standard voltage sampling module is used to sample the output voltage, obtain the voltage sampling signal and feed it back to the feedback compensation adjustment circuit.

[0012] Wherein, the feedback compensation adjustment circuit includes a first adjustable gain operational amplifier, a first adjustable phase shifter, a second adjustable gain amplifier, a second adjustable phase shifter, a first amplitude detector, a first phase detector, a second amplitude detector, a second phase detector, a single chip microcomputer and a display;

[0013] The input end of the first adjustable gain operational amplifier receives an initial current signal, and the output end of the first adjustable gain operational amplifier is connected to the current power amplifier through a first adjustable phase shifter; the input end of the second adjustable gain operational amplifier receives an initial voltage signal, and the output end of the second adjustable gain operational amplifier is connected to the voltage power amplifier through a second adjustable phase shifter;

[0014] The first amplitude detector is used to detect the amplitude of the initial current signal and the initial voltage signal, and the second amplitude detector is used to detect the amplitude of the voltage sampling signal and the current sampling signal; the first phase detector is used to detect the phase of the initial current signal and the initial voltage signal, and the second phase detector is used to detect the phase of the voltage sampling signal and the current sampling signal. The output ends of the first amplitude detector, the first phase detector, the second amplitude detector, and the second phase detector are all connected to the single-chip microcomputer, and the single-chip microcomputer is also connected to the display.

[0015] Furthermore, a PC and a serial port server are also provided in the programmable power source cabinet. The PC is connected to each direct digital synthesis signal source in the programmable power source, and the serial port server is respectively connected to a standard electric energy meter and an electric energy meter to be tested in each test station; the serial port server is also connected to the PC.

[0016] Furthermore, the multifunctional durability testing device also includes a power amplifier and a protection circuit. The output end of the power amplifier supplies power to the entire programmable power source cabinet after passing through the protection circuit.

[0017] The beneficial effects of the present invention are:

[0018] (1) The present invention adopts current and voltage conversion technology, which can output multiple current and voltage values ​​on one tester at the same time, meeting the requirements for simultaneous testing of electric energy meters with different current and voltage values.

[0019] (2) The present invention can provide long-term stable power output, ensuring that the measurement technical parameters can be effectively traced and calibrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the device principle of the present invention;

[0021] Figure 2 This is the principle block diagram of the programmable power source;

[0022] Figure 3 It is the principle diagram of the feedback compensation adjustment circuit;

[0023] Figure 4 Schematic diagram of the testing principle of the invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0025] like Figure 1 As shown, a multifunctional durability test device for electric energy meters comprises a program-controlled power source cabinet and a plurality of electric energy meter test assemblies, wherein the program-controlled power source cabinet is respectively connected to each electric energy meter test assembly;

[0026] The electric energy meter test assembly includes an ICT current transformer, a PT transformer and multiple test stations; the input end of the ICT current transformer is connected to the current output end of the programmable power source cabinet, and the output end of the ICT current transformer is connected to each test station; the input end of the PT transformer is connected to the voltage output end of the programmable power source cabinet, and the output end of the PT transformer is connected to each test station.

[0027] In the embodiment of the present application, each of the test stations of the electric energy meter test assembly is n ( Figure 1 Where n is 3), each test station is provided with an electric energy meter to be tested, wherein the electric energy meter to be tested in the first test station is the leading meter, and the electric energy meters to be tested in other test stations are test meters.

[0028] In the embodiment of the present application, the programmable power source cabinet is provided with a programmable power source and a standard electric energy meter; Figure 2 As shown, the program-controlled power source includes three signal generating channels, and the output signals of the signal generating channels are respectively transmitted to each electric energy meter test component after passing through the electric energy meter;

[0029] Each of the signal generation channels includes a direct digital synthesis signal source, a feedback compensation adjustment circuit, a current power amplifier, a current booster, a voltage power amplifier, a voltage booster, a standard current sampling module and a standard voltage sampling module; the direct digital synthesis signal source is used to generate an initial current signal and an initial voltage signal, the initial current signal passes through the current power amplifier and the current booster in sequence and then outputs the current signal to the outside, the standard current sampling module is used to sample the output current, obtain the current sampling signal and feed it back to the feedback compensation adjustment circuit; the initial voltage signal passes through the voltage power amplifier and the voltage booster and then outputs the signal to the outside, the standard voltage sampling module is used to sample the output voltage, obtain the voltage sampling signal and feed it back to the feedback compensation adjustment circuit.

[0030] In the embodiment of the present application, for a three-phase electric energy meter, each signal generating channel can generate one phase, for example, Figure 2In the embodiment, the first signal generating channel generates the current signal Ia and the voltage signal Ua of the A phase, the second signal generating channel generates the current signal Ib and the voltage signal Ub of the B phase, and the third signal generating channel generates the current signal Ic and the voltage signal Uc of the C phase;

[0031] like Figure 3 As shown, in an embodiment of the present application, the feedback compensation adjustment circuit includes a first adjustable gain operational amplifier, a first adjustable phase shifter, a second adjustable gain amplifier, a second adjustable phase shifter, a first amplitude detector, a first phase detector, a second amplitude detector, a second phase detector, a single chip microcomputer and a display;

[0032] The input end of the first adjustable gain operational amplifier receives an initial current signal, and the output end of the first adjustable gain operational amplifier is connected to the current power amplifier through a first adjustable phase shifter; the input end of the second adjustable gain operational amplifier receives an initial voltage signal, and the output end of the second adjustable gain operational amplifier is connected to the voltage power amplifier through a second adjustable phase shifter;

[0033] The first amplitude detector is used to detect the amplitude of the initial current signal and the initial voltage signal, and the second amplitude detector is used to detect the amplitude of the voltage sampling signal and the current sampling signal; the first phase detector is used to detect the phase of the initial current signal and the initial voltage signal, and the second phase detector is used to detect the phase of the voltage sampling signal and the current sampling signal. The first amplitude detector, the first phase detector, the second amplitude detector, and the second phase detector transmit the collected signals to the display through the single-chip microcomputer for display. The staff can observe the amplitude information of the initial current signal and the amplitude information of the sampled current signal, and judge whether the required current amplification factor has been achieved based on this. When the amplification requirements are not met, the amplitude of the current signal is adjusted through the first adjustable gain operational amplifier until the required amplification factor is reached; the staff can also judge whether the phases of the initial current signal and the sampled current signal are consistent through the phase information of the two, and when the phases are inconsistent, adjust them through the first adjustable phase shifter until the phases are consistent; similarly, the staff can judge whether the required voltage amplification factor has been achieved based on the amplitude of the initial voltage signal and the amplitude of the sampled voltage signal, and when the requirements are not met, adjust the amplitude of the voltage signal through the second adjustable gain amplifier until the required amplification factor is reached; the staff can judge whether the phases are consistent based on the phase of the initial voltage signal and the phase of the sampled voltage signal, and perform phase shift adjustment when the phases are inconsistent until the phases are consistent. In some other embodiments of the present application, the display may be removed, and the single-chip microcomputer may automatically calculate the amplification factor from the initial current signal to the sampled current signal, and the amplification factor from the initial voltage signal to the sampled voltage signal, and automatically compare them with the required amplification factors, and automatically control the first adjustable gain operational amplifier and the second adjustable gain amplifier to adjust accordingly until the required amplification factor is reached. Similarly, the single-chip microcomputer may automatically calculate the phase difference between the initial current signal and the sampled current signal, and calculate the phase difference between the initial voltage signal and the sampled voltage signal, and adjust the first adjustable phase shifter and the second adjustable phase shifter accordingly until the initial current signal and the sampled current signal are in phase with each other, and the initial voltage signal and the sampled voltage signal are in phase with each other.

[0034] In an embodiment of the present application, a PC and a serial port server are also provided in the programmable power source cabinet. The PC is connected to each direct digital synthesis signal source in the programmable power source, and the serial port server is respectively connected to a standard electric energy meter and an electric energy meter to be tested in each test station.

[0035] In an embodiment of the present application, the multifunctional durability testing device also includes a power amplifier and a protection circuit. The protection circuit may be a voltage stabilizing circuit, a power filter circuit, etc. In some embodiments, the protection circuit may also use smoke sensing and temperature detection technology to ensure that the power supply can be quickly cut off when the durability testing device is damaged to ensure the safety of the device operation; the output end of the power amplifier passes through the protection circuit to supply power to the entire programmable power source cabinet.

[0036] In an embodiment of the present application, cross-flow ventilation technology can also be added to the programmable power source cabinet. During the 1000-hour operation process, a cross-flow fan is used to draw cold air from the bottom of the cabinet and blow directly onto the surface of the power tube of the electronic power amplifier, so that the surface of the power tube is effectively cooled; hot air is drawn from the top of the cabinet to the outside of the cabinet; in this way, the ventilation of the cabinet of the durability test device can be ensured, and the temperature of the cabinet and the power amplifier will not be too high, thereby ensuring the long-term reliability of the device.

[0037] In the embodiments of the present application, a standard electric energy meter is used to monitor the output of the device and provide standard electrical parameters such as voltage, current, phase, and frequency; the electric energy meter durability test device adopts the standard electric energy meter method direct comparison principle to perform type testing. The standard electric energy meter is used to perform power comparison during the test process to ensure that the test process can monitor and compare the real-time power of the electric energy meter in real time, ensure the effectiveness of the test and the traceability of the electrical parameters. The serial port server is used to connect the PC to 485 channels such as the power source and the electric energy meter, and aggregate the data to the PC. The PC is connected to or has its own display to display the electrical parameter data of the tested electric energy meter, which is convenient for direct comparison with the standard.

[0038] In the embodiment of the present application, advanced direct digital synthesis signal technology is adopted. A digital synthesis sinusoidal signal source is composed of a powerful programmable digital logic array CPLD chip and a single-chip microcomputer as the core, and the set point of the sinusoidal signal with a frequency range of 45.000Hz ~ 65.000Hz and a phase of 0~360° is preset. The digital quantity parameters of the sinusoidal signal are stored in a specific memory, and a 3600-fold frequency clock is used as a periodic addressing signal to take out the sinusoidal signal parameters of the digital quantity. After conversion by a six-way digital / analog converter, a three-phase voltage and current approximate sinusoidal signal is obtained, and then after active low-pass filtering, it becomes a voltage and current sinusoidal signal with a distortion of less than 0.2%. The phase, amplitude, phase, and frequency of the voltage and current signals output by the digital synthesis sinusoidal signal source are all controllable. The load point requirements required for the calibration of the electric energy meter can be achieved by keyboard or PC control. The high stability DC reference benchmark of the standard phase-locked loop circuit and the digital / analog converter ensures the long-term stability of the output sinusoidal signal.

[0039] The power amplifier adopts a class AB programmable electronic power amplifier. The electronic power source can reach 0.03% (@3min). The use of programmable electronic power source ensures the stability and accuracy of power output and ensures stable error monitoring during the durability test process.

[0040] In the embodiment of the present application, the current signals Ia, Ib, and Ic generated by the programmable power source cabinet are connected to Figure 4 The current flows through the IAH, IBH, and ICH terminals, and the ICT transformer changes 100A into 80A, 60A, 40A, and other different current outputs, and then passes through Figure 4 The IAL, IBL, and ICL terminals are returned to the programmable power source cabinet. Each ICT can drive 1 to n electric energy meters. When electric energy meters of different current types are required for testing, multiple current electric energy meter tests can be carried out at the same time.

[0041] The voltage signals Ua, Ub, and Uc generated by the programmable power source are connected to Figure 4 UA, UB, UC terminals, PT transformer converts 220V into different voltage outputs such as 100V, 57.7V, etc. Each PT can drive 1~n electric energy meters. When electric energy meters of different voltage types are needed for testing, multiple voltage electric energy meter tests can be carried out at the same time.

[0042] In an embodiment of the present application, if a single-phase electric energy meter needs to be tested, the current signal and voltage signal output by the programmable power source can be converted into a single-phase signal, and then the electric energy meter test can be performed; in an embodiment of the present application, multiple groups of test stations can be added to directly test the signal output by the programmable power source on the main circuit of the programmable power source.

[0043] The working principle of the present invention is as follows: the voltage and current standard sinusoidal signals generated by the direct digital synthesis signal source are sent to the voltage power amplifier and the current power amplifier for power amplification through their respective feedback compensation adjustment circuits. The amplified sinusoidal voltage signal is sent to the calibrated meter and the standard electric energy meter after voltage boosting by the voltage transformer, and the amplified current signal is also sent to the calibrated meter and the standard electric energy meter after current boosting. The output voltage and current signals are sampled by current and voltage feedback and fed back to the feedback compensation adjustment circuit of the front stage of the power amplifier, which has high output stability and low distortion; the serial port server summarizes the data of each electric energy meter (the meter under test and the standard electric energy meter) to the PC computer, and the PC computer is connected to or has a built-in display to display and compare the electrical parameter data of the tested electric energy meter, which is convenient for direct comparison with the standard; because the present invention adopts current and voltage conversion (ICT, PT transformer) technology, it can output multiple different current and voltage values ​​on one test at the same time, meeting the requirements for simultaneous testing of electric energy meters with different current and voltage values.

[0044] The above description shows and describes a preferred embodiment of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. And the changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A multifunctional durability test device for electric energy meters, characterized in that: It includes a program-controlled power source cabinet and a plurality of electric energy meter test assemblies, wherein the program-controlled power source cabinet is connected to each electric energy meter test assembly respectively; The electric energy meter test assembly includes an ICT current transformer, a PT transformer and a plurality of test stations; the input end of the ICT current transformer is connected to the current output end of the program-controlled power source cabinet, and the output end of the ICT current transformer is connected to each test station; the input end of the PT transformer is connected to the voltage output end of the program-controlled power source cabinet, and the output end of the PT transformer is connected to each test station; Each of the electric energy meter test components has n test stations, and each test station is provided with an electric energy meter to be tested, wherein the electric energy meter to be tested in the first test station is a leading meter, and the electric energy meters to be tested in other test stations are test meters; The program-controlled power source cabinet is provided with a program-controlled power source and a standard electric energy meter; the program-controlled power source includes three signal generating channels, and the output signals of the signal generating channels are respectively transmitted to each electric energy meter test component after passing through the electric energy meter; Each of the signal generation channels includes a direct digital synthesis signal source, a feedback compensation adjustment circuit, a current power amplifier, a current booster, a voltage power amplifier, a voltage booster, a standard current sampling module and a standard voltage sampling module; the direct digital synthesis signal source is used to generate an initial current signal and an initial voltage signal, the initial current signal is sequentially passed through the current power amplifier and the current booster to output the current signal to the outside, the standard current sampling module is used to sample the output current, obtain the current sampling signal and feed it back to the feedback compensation adjustment circuit; the initial voltage signal is output to the outside after passing through the voltage power amplifier and the voltage booster, the standard voltage sampling module is used to sample the output voltage, obtain the voltage sampling signal and feed it back to the feedback compensation adjustment circuit; The feedback compensation adjustment circuit includes a first adjustable gain operational amplifier, a first adjustable phase shifter, a second adjustable gain amplifier, a second adjustable phase shifter, a first amplitude detector, a first phase detector, a second amplitude detector, a second phase detector, a single chip microcomputer and a display; The input end of the first adjustable gain operational amplifier receives an initial current signal, and the output end of the first adjustable gain operational amplifier is connected to the current power amplifier through a first adjustable phase shifter; the input end of the second adjustable gain operational amplifier receives an initial voltage signal, and the output end of the second adjustable gain operational amplifier is connected to the voltage power amplifier through a second adjustable phase shifter; The first amplitude detector is used to detect the amplitude of the initial current signal and the initial voltage signal, and the second amplitude detector is used to detect the amplitude of the voltage sampling signal and the current sampling signal; the first phase detector is used to detect the phase of the initial current signal and the initial voltage signal, and the second phase detector is used to detect the phase of the voltage sampling signal and the current sampling signal. The output ends of the first amplitude detector, the first phase detector, the second amplitude detector, and the second phase detector are all connected to the single-chip microcomputer, and the single-chip microcomputer is also connected to the display; The first amplitude detector, the first phase detector, the second amplitude detector, and the second phase detector transmit the collected signals to the display through the single-chip microcomputer for display. The single-chip microcomputer automatically calculates the amplification factor from the initial current signal to the sampled current signal, and the amplification factor from the initial voltage signal to the sampled voltage signal, and automatically compares them with the required amplification factors, and automatically controls the first adjustable gain operational amplifier and the second adjustable gain amplifier to adjust accordingly until the required amplification factor is reached. At the same time, the single-chip microcomputer automatically calculates the phase difference between the initial current signal and the sampled current signal, and calculates the phase difference between the initial voltage signal and the sampled voltage signal, and adjusts the first adjustable phase shifter and the second adjustable phase shifter accordingly until the initial current signal and the sampled current signal are in phase with each other, and the initial voltage signal and the sampled voltage signal are in phase with each other.

2. The multifunctional durability test device for electric energy meters according to claim 1 is characterized in that: The programmable power source cabinet is also provided with a PC and a serial port server. The PC is connected to each direct digital synthesis signal source in the programmable power source, and the serial port server is respectively connected to a standard electric energy meter and an electric energy meter to be tested in each test station; the serial port server is also connected to the PC.

3. The multifunctional durability test device for electric energy meters according to claim 1 is characterized in that: The multifunctional durability testing device also includes a power amplifier and a protection circuit. The output end of the power amplifier supplies power to the entire programmable power source cabinet after passing through the protection circuit.

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