CN112858991A - Uninterrupted verification system and method for low-voltage current transformer - Google Patents
Uninterrupted verification system and method for low-voltage current transformer Download PDFInfo
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- CN112858991A CN112858991A CN202110443641.4A CN202110443641A CN112858991A CN 112858991 A CN112858991 A CN 112858991A CN 202110443641 A CN202110443641 A CN 202110443641A CN 112858991 A CN112858991 A CN 112858991A
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- 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
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
Abstract
The invention provides a system and a method for calibrating a low-voltage current transformer without power failure, which belong to the technical field of low-voltage current transformers. According to the invention, the error detection is carried out on the low-voltage current transformer according to the detection regulation requirement under the condition that a low-voltage line is not powered off, the problem that the low-voltage current transformer cannot accurately measure under the condition that the line is not powered off at present is solved, the problem that the error condition under different current values cannot be detected is solved, and the fairness of measurement is ensured.
Description
Technical Field
The invention relates to the technical field of low-voltage current transformers, in particular to a system and a method for calibrating a low-voltage current transformer without power outage.
Background
The low-voltage current transformer is an important component of an electric energy metering device, is used for providing current signals with accurate proportion relation with a primary loop for electric measurement, electric energy metering and an automation device, and plays an important role in terminal electric energy metering.
Most of electric energy meters in the electric energy metering device carry out electric energy metering by collecting signals of a mutual inductor, so the accuracy of current and voltage conversion proportion of the mutual inductor directly determines the accuracy of electric energy metering. Meanwhile, the mutual inductor also plays a role in providing signals and isolating high voltage for instruments and relay protection, so that the reliability and the stability of the mutual inductor play a vital role in the safe operation and marketing measurement of the whole power system.
At present, a low-voltage electric energy metering device with load current larger than 60A in a power grid is generally composed of an electric energy meter and low-voltage current transformers, the low-voltage current transformers are widely applied and numerous, subsequent verification or verification in use is carried out after installation, power failure operation must be carried out on users, and the transformers need to be detached from a line, so that the low-voltage current transformers are not verified before the line is installed, subsequent verification and verification in use are not strictly carried out according to related verification rules after installation, if errors are out of tolerance or metering is inaccurate and cannot be found in time in use, the metering of the whole electric energy metering device is inaccurate, and the fairness and justness of metering are seriously influenced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the system and the method for calibrating the low-voltage current transformer without power outage, which are used for carrying out error calibration on the low-voltage current transformer according to calibration regulation requirements under the condition that a low-voltage line is not powered off, solving the problem that the conventional low-voltage current transformer cannot accurately measure under the condition that the line is not powered off, solving the problem that the error condition under different current values cannot be calibrated, and ensuring the fairness of measurement.
In order to achieve the above purposes, the technical scheme is as follows:
a low-voltage current transformer uninterrupted power verification system comprises a standard current transformer, a current booster, a phase-shifting power supply and a digital transformer calibrator;
the low-voltage current transformer and the standard current transformer are connected in series and arranged on a low-voltage line;
the phase-shifting power supply is connected in parallel with primary windings of the low-voltage current transformer and the standard current transformer through the current booster, and the phase-shifting power supply and the current booster are used for regulating testing primary current flowing through the low-voltage current transformer and the standard current transformer;
and secondary windings of the low-voltage current transformer and the standard current transformer are connected into a digital transformer calibrator, and the digital transformer calibrator is used for acquiring output signals of the low-voltage current transformer and the standard current transformer, calculating and analyzing the output signals to obtain an error calibration report.
Preferably, the uninterrupted verification system for the low-voltage current transformer further comprises:
the two taps of the output winding of the current booster are respectively connected with the insulated drainage wires, and the current booster is connected in parallel with the primary windings of the low-voltage current transformer and the standard current transformer through the two insulated drainage wires;
two insulating drainage wires are clamped at two ends of the low-voltage current transformer through the confluence clamp, and the standard current transformer clamp is arranged between the two confluence clamps.
Preferably, the uninterrupted verification system for the low-voltage current transformer further comprises:
the low-voltage current transformer is connected with a digital transformer calibrator through the sampling device;
the sampling device is used for converting an output signal of the low-voltage current transformer into sampling current and sending the sampling current to the digital transformer calibrator, and the digital transformer calibrator processes the sampling current to obtain an error calibration report.
Preferably, the load box includes:
the first branch, the second branch and the third branch are connected with a secondary winding of the low-voltage current transformer in parallel;
a first switch is arranged on the first branch;
a first resistor, a second resistor and a second switch are arranged on the second branch in series, and a third switch is arranged at two ends of the second resistor in parallel;
and a third resistor, a fourth resistor and a fourth switch are arranged on the third branch, and fifth switches are arranged at two ends of the fourth resistor in parallel.
Preferably, the sampling device comprises:
the sampling current transformer and the fifth resistor are arranged in parallel;
two output connectors of the sampling current transformer are connected with a digital transformer calibrator.
Preferably, the uninterrupted verification system for the low-voltage current transformer further comprises:
the standard sampling resistor assembly is connected with a secondary winding of a standard current transformer in parallel, and the standard current transformer is connected to the digital transformer calibrator through the standard sampling resistor assembly;
the standard sampling resistor assembly includes:
the fourth branch is connected with the secondary winding of the standard current transformer in parallel, and two ends of the fourth branch are connected with the digital transformer calibrator;
and a sixth resistor and a seventh resistor are connected in series on the fourth branch, and a sixth switch is connected in parallel at two ends of the sixth resistor.
A low-voltage current transformer uninterrupted power verification method comprises the following steps:
connecting a low-voltage current transformer in series with a standard current transformer;
connecting primary windings of a low-voltage current transformer and a standard current transformer in parallel to an output winding of a current booster, connecting a phase-shifting power supply in parallel to an input winding of the current booster, and connecting secondary windings of the low-voltage current transformer and the standard current transformer to a digital transformer calibrator;
the method comprises the steps that a voltage signal output by a phase-shifting power supply is adjusted according to a preset test requirement, a current booster receives the voltage signal and outputs an adjusting current, the testing primary current flowing through a low-voltage current transformer and a standard current transformer is adjusted through the adjusting current, and an error check report is obtained by acquiring output signals of the low-voltage current transformer and the standard current transformer through a digital transformer check meter, calculating and analyzing the output signals.
Preferably, the method further comprises:
connecting two taps of an output winding of the current booster with insulating drainage wires respectively, and connecting the current booster into primary windings of a low-voltage current transformer and a standard current transformer in parallel through the two insulating drainage wires;
two insulating drainage wires are clamped at two ends of the low-voltage current transformer through the confluence clamp, and the standard current transformer clamp is arranged between the two confluence clamps.
Preferably, the method further comprises:
connecting a sampling branch in parallel with a secondary winding of a low-voltage current transformer, wherein a load box and a sampling device are connected in series on the sampling branch, two output connectors of the sampling device are connected with a digital transformer calibrator, and the low-voltage current transformer is connected with the digital transformer calibrator through the sampling device;
and converting the output signal of the low-voltage current transformer into sampling current through a sampling device and sending the sampling current to a digital transformer calibrator, and processing the sampling current by the digital transformer calibrator to obtain an error calibration report.
Preferably, the method further comprises:
a standard sampling resistor assembly is connected in parallel with a secondary winding of a standard current transformer, and the standard current transformer is connected with a digital transformer calibrator through the standard sampling resistor assembly.
The invention has the beneficial effects that: the standard current transformer and the low-voltage current transformer are introduced to carry out comparison and analysis of output signals to obtain error data, a secondary winding of the standard current transformer only needs to be one group, two wiring terminals of a measuring winding are only needed to be switched during secondary loop measurement, an error test of the current transformer can be completed through one-time wiring, system wiring is simple, and error verification can be carried out only through a design accuracy grade 0.05-level digital calibrator.
Error data are obtained through automatic acquisition and analysis of the digital transformer calibrator, the system is simple in wiring and high in automation degree, and the error test of the current transformer can be completed through one-time wiring.
A voltage signal generated by the phase-shifting power supply generates an adjusting current meeting the testing requirement through the current booster, and the adjusting current is connected in series with the low-voltage current transformer and the standard current transformer, so that the current value of the testing primary current flowing through the low-voltage current transformer and the standard current transformer is adjusted, and error data of the low-voltage current transformer under different current values is verified through the digital transformer calibrator.
Drawings
Fig. 1 is a schematic circuit diagram of a non-power-off verification system for a low-voltage current transformer in an embodiment of the invention.
Fig. 2 is a schematic circuit diagram of the secondary winding of the low-voltage current transformer connected to the load box in the embodiment of the invention.
Fig. 3 is a schematic circuit diagram of a secondary winding of a standard current transformer connected to a standard sampling resistor component according to an embodiment of the present invention.
Reference numerals:
1-a low-voltage current transformer; 2-standard current transformer; 3-a current booster; 4-a phase-shifting power supply; 5, insulating a drainage wire; 6-a load box; 7-a sampling device; 8-standard sampling resistance component; 9-digital mutual inductor calibrator; 10-sampling a current transformer; 11-a first switch; 12-a second switch; 13-a first resistance; 14-a second resistance; 15-a third switch; 16-a third resistance; 17-a fourth resistance; 18-a fifth switch; 19-a fourth switch; 20-sixth resistance; 21-seventh resistance; 22-a sixth switch; 23-fifth resistance; 24-load resistance; 25-control cabinet.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific examples described herein are intended to be illustrative only and are not intended to be limiting. Moreover, all other embodiments that can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort belong to the protection scope of the present invention.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the invention provides a system for calibrating a low-voltage current transformer without power outage, which comprises a standard current transformer 2, a current booster 3, a phase-shifting power supply 4 and a digital transformer calibrator 9. In the specification parameter design of the low-voltage current transformer 1, the rated primary current is generally designed to be 1000A, and the accuracy level is 0.05 level.
The standard current transformer 2 and the low-voltage current transformer 1 are connected in series and arranged on a low-voltage line. The phase-shifting power supply 4 is connected in parallel with primary windings of the low-voltage current transformer 1 and the standard current transformer 2 through the current booster 3, and the phase-shifting power supply 4 and the current booster 3 are used for regulating testing primary current flowing through the low-voltage current transformer 1 and the standard current transformer 2. The secondary windings of the low-voltage current transformer 1 and the standard current transformer 2 are connected to a digital transformer calibrator 9, and output signals of the low-voltage current transformer 1 and the standard current transformer 2 are collected through the digital transformer calibrator 9 and are compared and analyzed to obtain an error detection report.
In this embodiment, the amplitude and the phase of the output voltage of the phase-shift power supply 4 are adjusted, the current booster 3 outputs an adjustment current, and the test primary current flowing through the low-voltage current transformer 1 and the standard current transformer 2 can be adjusted by adjusting the current, wherein the test primary current is 1% -120% of the continuously adjustable current flowing through the primary loop of the low-voltage current transformer 1.
The error measurement of the low-voltage current transformer 1 can be performed by a sampling difference comparison method (a difference measurement method) and a direct comparison method. The present application employs a direct comparison method for the reasons described below.
The differential measurement method requires that the transformation ratio of the low-voltage current transformer 1 and the standard current transformer 2 is the same, the secondary wiring is a differential measurement loop, for the detection without power failure, the primary loop circuit is required to be incapable of power failure, and the secondary wiring of the low-voltage current transformer 1 is required to be untied, so that the standard current transformer 2 must adopt an open structure, and the design difficulty is high according to the detection requirement of 0.05S level; because of 1 primary current specification of low-voltage current transformer is more, require 2 secondary windings of standard current transformer to take a percentage more promptly, more increased the design degree of difficulty, and secondary winding need connect into the measuring difference return circuit, and the wiring is comparatively complicated, and it is more to detect the potential safety hazard with electricity.
The direct comparison rule is that only one group of 2 secondary windings of the standard current transformer is needed, only 2 wiring terminals of the measuring windings need to be switched during the measurement of the secondary circuit, the wiring is simple, and the error verification can be carried out only by designing the digital transformer calibrator 9 with the accuracy grade of 0.05. Therefore, the system adopts a direct comparison method to carry out error detection.
The output signals of the standard current transformer 2 and the low-voltage current transformer 1 are automatically acquired through the digital transformer calibrator 9, and are compared and analyzed to obtain error data, so that the system is high in automation degree.
The method comprises the steps that a phase-shifting power supply 4 and a current booster 3 are introduced, a voltage signal generated by the phase-shifting power supply 4 generates an adjusting current meeting testing requirements (the testing requirements are preset in advance, for example, the testing requirements are requirements for detecting error conditions and operation conditions of the low-voltage current transformer 1 under a plurality of preset current values) through the current booster 3, the adjusting current is connected in series with the low-voltage current transformer 1 and a standard current transformer 2, so that the current values flowing through the low-voltage current transformer 1 and the standard current transformer 2 are adjusted, and error data of the low-voltage current transformer 1 under different current values are verified through a digital transformer calibrator 9.
Before the uninterrupted power verification test is started, the information of the low-voltage current transformer 1 can be input or scanned to the digital transformer calibrator 9, the test state and data can be transmitted in real time during the test, the digital transformer calibrator 9 can automatically generate an original record and an error detection report after the test is completed, and related verification results can be wirelessly transmitted to a remote control host or a data terminal, so that the integrity and the accuracy of the data are ensured, the accuracy and the effectiveness of field electric energy metering results are ensured, and the automation degree of the system is improved.
In a preferred embodiment, the uninterruptible verification system for the low-voltage current transformer further includes:
the two taps of the output winding of the current rising device 3 are respectively connected with the insulated drainage wire 5, and the current rising device 3 is connected in parallel with the primary windings of the low-voltage current transformer 1 and the standard current transformer 2 through the two insulated drainage wires 5. Two insulating drainage wires 5 are clamped at two ends of the low-voltage current transformer 1 through the confluence clamp, and the standard current transformer 2 is clamped between the two confluence clamps.
In the embodiment, the large-current insulated drainage wire 5 is clamped to two ends of a branch where the low-voltage current transformer 1 and the standard current transformer 2 are located, the amplitude and the phase of the output voltage of the phase-shifting power supply 4 are adjusted, and the adjusting current is output through the current booster 3, so that 1% -120% of continuously adjustable testing current is obtained in a primary loop of the low-voltage current transformer 1, and the low-voltage current transformer 1 with the primary current of 100-1000A and the secondary current of 5A can be subjected to non-power-outage verification.
In a preferred embodiment, the uninterruptible verification system for the low-voltage current transformer further includes:
the low-voltage current transformer 1 is connected with a digital transformer calibrator 9 through the sampling device 7. The sampling device 7 is used for converting an output signal of the low-voltage current transformer 1 into a sampling current and sending the sampling current to the digital transformer calibrator 9, and the digital transformer calibrator 9 processes the sampling current to obtain an error calibration report. The secondary winding sampling signal (output signal) of the low-voltage current transformer 1 is sent to a sampling channel CH1 of the digital transformer calibrator 9 through a sampling device 7.
In the preferred embodiment, the load box 6 includes:
and the first branch, the second branch and the third branch are connected with the secondary winding of the low-voltage current transformer 1 in parallel. The first branch is provided with a first switch 11. The second branch is provided with a first resistor 13, a second resistor 14 and a second switch 12 in series, and a third switch 15 is connected in parallel at two ends of the second resistor 14. And a third resistor 16, a fourth resistor 17 and a fourth switch 19 are arranged on the third branch, and a fifth switch 18 is arranged at two ends of the fourth resistor 17 in parallel.
In this embodiment, the rated load and the lower limit load are switched manually or automatically to meet the requirement of error verification.
In a preferred embodiment, the sampling means 7 comprise:
the sampling current transformer 10 and the fifth resistor 23 are arranged in parallel. Two output connectors of the sampling current transformer 10 are connected to the digital transformer calibrator 9.
In this embodiment, the low-voltage current transformer 1 is usually installed in the control cabinet 25, and when the sampling device 7 is connected in parallel to the secondary winding of the low-voltage current transformer 1, the testing wire clamps are arranged at the two ends of the sampling device 7 and clamped on the two wiring terminals of the secondary winding of the low-voltage current transformer 1, so as to ensure that the two wiring sheets are disconnected after good wiring, thereby ensuring that the low-voltage current transformer 1 cannot be opened in the whole testing process, and ensuring the safety of testing personnel and testing equipment. The sampling current transformer 10 can adopt a core-through current transformer, and the precision grade is 0.01S grade. In a preferred embodiment, the uninterruptible verification system for the low-voltage current transformer further includes:
and the standard sampling resistor component 8 is connected with the secondary winding of the standard current transformer 2 in parallel, and the standard current transformer 2 is connected into the digital transformer calibrator 9 through the standard sampling resistor component 8.
The standard sampling resistor assembly 8 includes:
and a fourth branch circuit connected with the secondary winding of the standard current transformer 2 in parallel, wherein both ends of the fourth branch circuit are connected with a digital transformer calibrator 9. A sixth resistor 20 and a seventh resistor 21 are connected in series to the fourth branch, and a sixth switch 22 is connected in parallel to two ends of the sixth resistor 20.
In this embodiment, the resistance ratio of the sixth resistor 20 to the seventh resistor 21 is 9: 1. In order to meet the calibration requirements under the primary current 100A-1000A and 1% regulation point and improve the signal intensity of the secondary current, the amplification times of the standard sampling resistor component 8 are x1 and x10 respectively, the primary current <100A adopts x10 to measure small current, the primary current >100A is switched to x1 to measure, the output intensity of sampling signals is improved, and the sampling signals of the secondary winding of the standard current transformer 2 are sent to a sampling channel CH2 of a digital transformer calibrator 9.
Further, a load resistor 24 is arranged in the low-voltage line to simulate the actual working state of the line.
In a preferred embodiment, the uninterruptible verification system for the low-voltage current transformer further includes:
the application also provides a method for calibrating the low-voltage current transformer 1 without power outage, which comprises the following steps: the low-voltage current transformer 1 is connected with a standard current transformer 2 in series.
The primary windings of the low-voltage current transformer 1 and the standard current transformer 2 are connected in parallel to an output winding of the current booster 3, the phase-shifting power source 4 is connected in parallel to an input winding of the current booster 3, and the secondary windings of the low-voltage current transformer 1 and the standard current transformer 2 are connected to the digital transformer calibrator 9.
The voltage signal output by the phase-shifting power supply 4 is adjusted according to the preset test requirement, the current booster 3 receives the voltage signal and outputs the adjusting current, the testing primary current flowing through the low-voltage current transformer 1 and the standard current transformer 2 is adjusted through the adjusting current, and the output signals of the low-voltage current transformer 1 and the standard current transformer 2 are collected through the digital transformer calibrator 9 and are calculated and analyzed to obtain an error calibration report.
In this embodiment, the standard current transformer 2 and the low-voltage current transformer 1 are introduced to perform comparative analysis on output signals to obtain error data. By adopting a method of system integral calibration, a secondary winding of a standard current transformer 2 is connected to a terminal of a low-voltage current transformer 1 to measure error data, the measurement error characteristic of the whole calibrating device (comprising the standard current transformer 2 and the low-voltage current transformer 1) is obtained, and a digital transformer calibrator 9 corrects the error of the whole calibrating device to ensure that the whole calibrating device meets the requirement of 0.05 level.
Aiming at the unstable data caused by the poor contact of the contact surface of the open type standard current transformer 2, the unstable data can be avoided through the repeatability and stability test.
In a specific embodiment, the current booster 3, the phase-shifting power supply 4 and the digital transformer calibrator 9 can be integrated in a chassis, so as to realize power supply output regulation, load switching and error testing.
The digital mutual inductor calibrator 9 is composed of a multi-channel high-precision acquisition board card and an industrial computer, a terminal adopts a large-screen liquid crystal display, and a test result is clear.
The verification system software of the digital transformer calibrator 9 adopts mainstream, mature software products which meet industry standards, and based on an operation system of the industry mainstream, a human-computer interface adopts an operation interface with consistent style, so that the layout is reasonable, the window content is simple and clear, the provided information language is popular, easy to understand and consistent, a test data report can be output, a complete detection report can be finally formed, and the report can be derived to be stored as an EXCEL or WORD document. The report forms adopt a specified uniform data format.
The verification system of the digital transformer calibrator 9 can input or scan the information of the low-voltage current transformer 1 into the device, can transmit the test state and data in real time in a wireless mode, and can wirelessly transmit the verification result to a remote control host or a data terminal, so that the universal power internet of things interconnection and intercommunication requirement is met.
In the parameter setting of the phase-shifting power supply 4, the capacity is 5kVA, the input voltage is 220V ± 10% (two phases), the frequency is 50 ± 0.5Hz, the waveform distortion is not more than 5%, the output voltage is 0-250V, and the phase-shifting range is 0-180 °.
In the parameter setting of the current booster 3, the capacity is 5kVA, the input voltage is 0-240V, and the output current is 0-1200A.
In the parameter setting of the open type standard current transformer 2, the rated primary current is 1000A, the rated secondary current is 1A, and the accuracy level is 0.05 level.
In the parameter setting of the load box 6, the rated current is 5A, the working range is 1-120%, the rated loads are 2.5VA, 3.75VA, 5VA and 10VA, the power factor is 0.8, and the accuracy is +/-3%.
In the parameter setting of the digital transformer calibrator 9, the accuracy level is 0.05 level, the sampling channel is typically 2 channels, and is expandable to 8 channels, and the AD conversion resolution is 24 bits. The system has a humanized human-computer interaction interface, a simple interface, clear logic and easy practical operation. The functions of parameter setting, data display, data storage, automatic report output and the like can be realized. The device has an interface for convenient communication, can be networked, and facilitates data copying. The wiring mode is simple and clear, and the plug and play protection device has protection measures for preventing misplug. The data transmission modes include a wired mode and a wireless mode (WIFI and 2G/3G/4G network).
The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention. Those not described in detail in this specification are within the skill of the art.
Claims (10)
1. A low-voltage current transformer uninterrupted power verification system is characterized by comprising a standard current transformer (2), a current booster (3), a phase-shifting power supply (4) and a digital transformer calibrator (9);
the low-voltage current transformer (1) and the standard current transformer (2) are connected in series and arranged on a low-voltage line;
the phase-shifting power supply (4) is connected in parallel with primary windings of the low-voltage current transformer (1) and the standard current transformer (2) through the current booster (3), and the phase-shifting power supply (4) and the current booster (3) are used for regulating test primary current flowing through the low-voltage current transformer (1) and the standard current transformer (2);
and secondary windings of the low-voltage current transformer (1) and the standard current transformer (2) are connected into a digital transformer calibrator (9), and the digital transformer calibrator (9) is used for collecting output signals of the low-voltage current transformer (1) and the standard current transformer (2) and performing calculation and analysis to obtain an error calibration report.
2. The uninterrupted power verification system for the low-voltage current transformer according to claim 1, wherein the uninterrupted power verification system for the low-voltage current transformer further comprises:
the two taps of the output winding of the current booster (3) are respectively connected with the insulated drainage wire (5), and the current booster (3) is connected in parallel with the primary windings of the low-voltage current transformer (1) and the standard current transformer (2) through the two insulated drainage wires (5);
two insulating drainage wires (5) are clamped at two ends of the low-voltage current transformer (1) through a confluence clamp, and the standard current transformer (2) is clamped between the two confluence clamps.
3. The uninterrupted power verification system for the low-voltage current transformer according to claim 1, wherein the uninterrupted power verification system for the low-voltage current transformer further comprises:
the low-voltage current transformer calibration device comprises a load box (6) and a sampling device (7) which are connected in series, the load box and the sampling device are connected in parallel with a secondary winding of the low-voltage current transformer (1) after being connected in series, and the low-voltage current transformer (1) is connected into a digital transformer calibrator (9) through the sampling device (7);
the sampling device (7) is used for converting an output signal of the low-voltage current transformer (1) into a sampling current and sending the sampling current to the digital transformer calibrator (9), and the digital transformer calibrator (9) processes the sampling current to obtain an error calibration report.
4. The uninterrupted verification system for the low-voltage current transformer according to claim 3, wherein the load box (6) comprises:
the first branch, the second branch and the third branch are connected with a secondary winding of the low-voltage current transformer (1) in parallel;
a first switch (11) is arranged on the first branch;
a first resistor (13), a second resistor (14) and a second switch (12) are arranged on the second branch in series, and a third switch (15) is arranged at two ends of the second resistor (14) in parallel;
and a third resistor (16), a fourth resistor (17) and a fourth switch (19) are arranged on the third branch, and a fifth switch (18) is arranged at two ends of the fourth resistor (17) in parallel.
5. The uninterrupted verification system for the low-voltage current transformer according to claim 3, wherein the sampling device (7) comprises:
the sampling current transformer (10) and the fifth resistor (23) are arranged in parallel;
two output connectors of the sampling current transformer (10) are connected to a digital transformer calibrator (9).
6. The uninterrupted power verification system for the low-voltage current transformer according to claim 3, wherein the uninterrupted power verification system for the low-voltage current transformer further comprises:
the standard sampling resistor component (8) is connected with a secondary winding of the standard current transformer (2) in parallel, and the standard current transformer (2) is connected to the digital transformer calibrator (9) through the standard sampling resistor component (8);
the standard sampling resistor assembly (8) comprises:
a fourth branch circuit connected with the secondary winding of the standard current transformer (2) in parallel, wherein both ends of the fourth branch circuit are connected with a digital transformer calibrator (9);
and a sixth resistor (20) and a seventh resistor (21) are connected in series on the fourth branch, and a sixth switch (22) is connected in parallel at two ends of the sixth resistor (20).
7. A low-voltage current transformer uninterrupted power verification method is characterized by comprising the following steps:
connecting the low-voltage current transformer (1) with a standard current transformer (2) in series;
connecting primary windings of a low-voltage current transformer (1) and a standard current transformer (2) in parallel to an output winding of a current booster (3), connecting a phase-shifting power supply (4) in parallel to an input winding of the current booster (3), and connecting secondary windings of the low-voltage current transformer (1) and the standard current transformer (2) to a digital transformer calibrator (9);
the method comprises the steps that a voltage signal output by a phase-shifting power supply (4) is adjusted according to a preset test requirement, a current booster (3) receives the voltage signal and outputs an adjusting current, the testing primary current flowing through a low-voltage current transformer (1) and a standard current transformer (2) is adjusted through the adjusting current, and an error check report is obtained by collecting output signals of the low-voltage current transformer (1) and the standard current transformer (2) through a digital transformer check meter (9) and carrying out calculation analysis.
8. The method for calibrating the low-voltage current transformer without power outage as claimed in claim 7, wherein the method further comprises the following steps:
two taps of an output winding of the current booster (3) are respectively connected with an insulating drainage wire (5), and the current booster (3) is connected in parallel with primary windings of the low-voltage current transformer (1) and the standard current transformer (2) through the two insulating drainage wires (5);
two insulating drainage wires (5) are clamped at two ends of the low-voltage current transformer (1) through a confluence clamp, and the standard current transformer (2) is clamped between the two confluence clamps.
9. The method for calibrating the low-voltage current transformer without power outage as claimed in claim 7, wherein the method further comprises the following steps:
a sampling branch is connected in parallel with a secondary winding of a low-voltage current transformer (1), a load box (6) and a sampling device (7) are connected in series on the sampling branch, two output connectors of the sampling device (7) are connected into a digital transformer calibrator (9), and the low-voltage current transformer (1) is connected into the digital transformer calibrator (9) through the sampling device (7);
the output signal of the low-voltage current transformer (1) is converted into sampling current through the sampling device (7) and is sent to the digital transformer calibrator (9), and the digital transformer calibrator (9) processes according to the sampling current to obtain an error calibration report.
10. The method for calibrating the low-voltage current transformer without power outage as claimed in claim 7, wherein the method further comprises the following steps:
a standard sampling resistor component (8) is connected in parallel to a secondary winding of a standard current transformer (2), and the standard current transformer (2) is connected to a digital transformer calibrator (9) through the standard sampling resistor component (8).
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| CN202110443641.4A CN112858991B (en) | 2021-04-23 | 2021-04-23 | Uninterrupted verification system and method for low-voltage current transformer |
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| CN202110443641.4A CN112858991B (en) | 2021-04-23 | 2021-04-23 | Uninterrupted verification system and method for low-voltage current transformer |
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| CN112858991A true CN112858991A (en) | 2021-05-28 |
| CN112858991B CN112858991B (en) | 2022-02-01 |
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| CN202110443641.4A Active CN112858991B (en) | 2021-04-23 | 2021-04-23 | Uninterrupted verification system and method for low-voltage current transformer |
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| CN116381590A (en) * | 2023-06-07 | 2023-07-04 | 云南电网有限责任公司 | Current transformer electrified checking system, self-calibration method and use method |
| CN117420493A (en) * | 2023-11-09 | 2024-01-19 | 国网四川省电力公司营销服务中心 | Electrical energy metering device uncertainty testing system |
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| CN116381590B (en) * | 2023-06-07 | 2023-09-19 | 云南电网有限责任公司 | Current transformer electrified checking system, self-calibration method and use method |
| CN117420493A (en) * | 2023-11-09 | 2024-01-19 | 国网四川省电力公司营销服务中心 | Electrical energy metering device uncertainty testing system |
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