CN112735755B - High-precision multi-transformation-ratio standard current transformer working for long time at 150% rated current - Google Patents
High-precision multi-transformation-ratio standard current transformer working for long time at 150% rated current Download PDFInfo
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- CN112735755B CN112735755B CN202011420185.3A CN202011420185A CN112735755B CN 112735755 B CN112735755 B CN 112735755B CN 202011420185 A CN202011420185 A CN 202011420185A CN 112735755 B CN112735755 B CN 112735755B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/08—Cooling; Ventilating
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
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Abstract
The invention relates to a high-precision multi-transformation-ratio standard current transformer capable of working for a long time at 150% of rated current, and belongs to the technical field of electric energy metering. The invention comprises a shell, a primary winding, a secondary winding, an air channel, an insulating film, an iron core, an error compensation unit, a power supply and control module, a man-machine interaction unit, a fan, a self-locking universal wheel and a wiring terminal row. The invention adopts the modes of applying heat dissipation measures, error compensation measures and the like to ensure the measurement accuracy and stability of the standard current transformer for long-term working for 1 hour under the condition of 150% of rated current, and simultaneously meets the measurement accuracy and stability under the condition of 1% -120% of rated current.
Description
Technical Field
The invention relates to a high-precision multi-transformation-ratio standard current transformer capable of working for a long time at 150% of rated current, and belongs to the technical field of electric energy metering.
Background
A current transformer is a transformer used to transmit information signals to measuring instruments, meters and protection or control devices or similar electrical appliances. The current transformer can convert large current into small current for measuring or protecting the system. The measurement accuracy of the current transformer is related to the fairness and justice of trade settlement among distribution, supply and use, and the reliable operation of the current transformer is related to the power utilization safety of a power grid.
Because the current transformer production enterprises for metering of 35kV and below have low technical and capital thresholds and wide product demand, the current industry integrally presents the current situations of low industrial concentration, numerous manufacturers, good and uneven product quality and the like, and a plurality of problems are brought to power enterprises, for example: the difficulty of controlling the product quality in purchasing, operation and other links is high, and the quality of the metering current transformer of 35kV or below in operation has great hidden danger, so that trade settlement disputes and power grid operation problems occur, the failure rate is high, and even the phenomena of equipment explosion or burning and the like occur.
In order to solve the problems, not only the current transformer in the operation process needs to be strictly detected, but also the current transformer for electric power needs to be subjected to full-performance detection before bidding purchase. The method comprises tests such as current transformer error, overload and withstand voltage, wherein the error and overload tests in the full-performance test are core tests, and the two test results are closely related to the accuracy and safety of the tested current transformer.
According to the calibration rule and the related technical specification, the error test of the current transformer requires that the error of the current transformer is measured when the current transformer works at 1% -120% of rated current; the overload capacity test of the current transformer requires that the current transformer works for a long time under 150% rated primary current, and measures the error of the current transformer, wherein the error requirement meets the requirement of regulation limit.
The overload capacity test and the error test of the current transformer have the same required test equipment, and the overload capacity test and the error test of the current transformer comprise an up-flow power supply, a voltage regulating power supply, a standard current transformer, a load box and a transformer calibrator, and can share one set of equipment to realize two tests. The equipment is required to work for a long time, particularly a standard current transformer is required to work for 1 hour or more at 150% rated current for a long time, and the accuracy of the equipment is maintained. The standard current transformer belongs to a precise instrument, and heat brought by long-time work can seriously affect the error characteristic of the standard current transformer and even burn out equipment. Due to the fact that a plurality of testing mechanisms lack a standard current transformer capable of operating at 150% rated current for a long time, overload tests of the current transformer are difficult to effectively carry out and even cannot be carried out, and evaluation and judgment of the quality of the current transformer are affected.
Disclosure of Invention
Aiming at the problems, the invention designs the high-precision multi-transformation-ratio standard current transformer which works for a long time under the rated current of 150 percent, and the invention ensures the measurement accuracy and stability of the standard current transformer which works for 1 hour under the condition of 150 percent of rated current by applying heat dissipation measures, error compensation measures and the like, and simultaneously meets the measurement accuracy and stability under the rated current of 1 percent to 120 percent. The invention provides technical support for overload and error tests of the current transformer, and is beneficial to enhancing the management of the work of network access detection, goods acceptance, operation quality, production, manufacturing and the like of the current transformer.
The technical scheme of the invention is as follows: a high-precision multi-transformation-ratio standard current transformer working for a long time at 150% rated current comprises a shell, a primary winding, a secondary winding, an air channel, an insulating film, an iron core, an error compensation unit, a power supply and control module, a fan, a self-locking universal wheel and a wiring terminal row;
the primary winding, the secondary winding, the air channel, the insulating film, the iron core, the error compensation unit, the power supply and control module and the fan are all positioned in the shell; the self-locking universal wheels are positioned at four corners of the bottom of the shell; the wiring terminal block is positioned above the shell, and the man-machine interaction unit is embedded above the shell;
the iron core of the standard current transformer is of an annular structure; a primary winding L1-L2 and a secondary winding K1-Km are uniformly wound on an iron core; the secondary winding layers, the primary winding layers and the primary winding and the secondary winding are insulated by adopting diamond insulating films; the iron core, the primary winding, the secondary winding, the diamond grid insulating film and the air passage form a coil of the standard current transformer, and the human-computer interaction unit is connected with the control module.
As a further scheme of the invention, a plurality of layers of air passages are arranged on a coil of the standard current transformer, a circle of air passages are arranged on the coil every N layers of windings, the air passages are wound on an iron core by a plurality of paper board strips with the width of x mm and the thickness of y mm, and the winding direction of the paper board strips is vertical to the winding direction of the windings; a plurality of cardboard strip evenly distributed is on the iron core.
As a further scheme of the invention, the paperboard strips of each layer of air passage are wound in a staggered mode, so that the heat dissipation effect is further improved.
As a further scheme of the invention, the standard current transformer shell is of a cuboid structure.
As a further scheme of the invention, the fan of the standard current transformer comprises an air inlet fan and an air outlet fan, the air inlet fan is arranged above a front side panel of a shell of the standard current transformer, the air outlet fan is arranged above a rear side panel of the shell of the standard current transformer, the air inlet fan and the air outlet fan are positioned at the same horizontal position, and the air inlet fan and the air outlet fan work simultaneously to form an air channel to take away heat of a coil of the standard current transformer.
As a further scheme of the invention, the standard current transformer shell is further provided with a temperature and humidity monitoring device, the unit is connected with the power supply and control module and is used for monitoring the temperature and humidity condition in the shell, and when the temperature and humidity exceed the threshold requirement, the power supply and control module controls the power off to terminate the test.
As a further scheme of the invention, the front side, the rear side, the left side and the right side of the standard current transformer are respectively provided with a vent hole for heat dissipation of the standard current transformer.
As a further scheme of the invention, the error compensation unit of the standard current transformer is composed of N groups of compensation capacitors, N relays and a compensation winding, wherein the compensation winding is wound on an iron core, and the compensation capacitors and the relays are connected in series and then connected in parallel to the compensation winding; the control unit realizes the access of the compensation capacitor by controlling the switching of the relay, and the compensation accuracy is guaranteed.
As a further scheme of the invention, the secondary winding of the standard current transformer comprises a plurality of windings or taps K1-Km, the secondary winding and the primary winding L1-L2 form currents with a plurality of transformation ratios through excitation of an iron core, standard current transformation ratio information is input to the man-machine interaction unit, and the control unit controls switching of the relay to realize cascade connection and selection of the plurality of secondary windings, so that different transformation ratios are output.
A method for carrying out segmented adaptive compensation by using the standard current transformer comprises the following steps: and segmenting the working current of the standard current transformer into N segments, wherein each segment corresponds to one compensation capacitor, the working current of the standard current transformer is identified through the power supply and control module, and the compensation capacitor is judged and selected.
The invention has the beneficial effects that:
1. the high-precision multi-transformation-ratio standard current transformer working for a long time under 150% rated current provided by the invention adopts measures such as a wire cladding air passage applying heat dissipation method, a segmented compensation method, a compensation winding parallel capacitance error compensation method, a multi-secondary winding segmented cascade method and the like, so that the measurement precision of the standard current transformer working for a long time is guaranteed. The temperature and humidity monitoring device is further arranged, so that dangerous conditions can be warned in time, and the safety of the current transformer test is improved. The invention also has the advantage of wide working range, the error can meet the requirement of 0.01S level under the range of 1% -150% of rated current of 10A, 15A, 20A, 30A, 40A, 50A, 75A, 100A, 150A, 200A, 300A, 400A, 500A, 600A, 750A and 1000A, the invention can work for 1 hour under the condition of 150% of rated primary current, and the measurement error meets the requirement of accuracy and stability of 0.01S level.
2. The invention adopts a miniaturized and movable design, and is convenient for laboratories and field tests of the current transformer.
3. The invention has multiple heat dissipation and error compensation measures, high accuracy, good stability, small volume, light weight and easy movement, is very suitable for the error and overload capacity test of the current transformer, is suggested to be applied to the performance test of the current transformer of 35kV or below, and can also be applied to the design of standard current transformers in other current ranges by popularizing project technologies.
Drawings
FIG. 1 is a schematic view of the airway distribution of the present invention;
fig. 2 is a schematic diagram of the compensation of the present invention.
Detailed Description
Without loss of generality, the present invention will be further described by taking an example of carrying out overload capability test and error test of a current transformer by using a high-precision multi-transformation ratio standard current transformer which works at 150% rated current for a long time.
Example 1: as shown in fig. 1-2, a high-precision multi-transformation-ratio standard current transformer which works for a long time under 150% rated current comprises a shell, a primary winding, a secondary winding, an air channel, an insulating film, an iron core, an error compensation unit, a power supply and control module, a fan, a self-locking universal wheel and a wiring terminal row;
the primary winding, the secondary winding, the air channel, the insulating film, the iron core, the error compensation unit, the power supply and control module and the fan are all positioned in the shell; the self-locking universal wheels are positioned at four corners of the bottom of the shell; the wiring terminal block is positioned above the shell, and the man-machine interaction unit is embedded above the shell;
the iron core of the standard current transformer is of an annular structure; a primary winding L1-L2 and a secondary winding K1-Km are uniformly wound on an iron core; the secondary winding layers, the primary winding layers and the primary winding and the secondary winding are insulated by adopting diamond insulating films; the iron core, the primary winding, the secondary winding, the diamond grid insulating film and the air passage form a coil of the standard current transformer, and the human-computer interaction unit is connected with the control module.
As a further scheme of the invention, a plurality of layers of air passages are arranged on a coil of the standard current transformer, a circle of air passages are arranged on the coil every N layers of windings, the air passages are wound on an iron core by a plurality of paper board strips with the width of x mm and the thickness of y mm, and the winding direction of the paper board strips is vertical to the winding direction of the windings; a plurality of cardboard strip evenly distributed is on the iron core.
As a further scheme of the invention, the paperboard strips of each layer of air passage are wound in a staggered mode, so that the heat dissipation effect is further improved.
As a further scheme of the invention, the standard current transformer shell is of a cuboid structure.
As a further scheme of the invention, the fan of the standard current transformer comprises an air inlet fan and an air outlet fan, the air inlet fan is arranged above a front side panel of a shell of the standard current transformer, the air outlet fan is arranged above a rear side panel of the shell of the standard current transformer, the air inlet fan and the air outlet fan are positioned at the same horizontal position, and the air inlet fan and the air outlet fan work simultaneously to form an air channel to take away heat of a coil of the standard current transformer.
As a further scheme of the invention, the standard current transformer shell is further provided with a temperature and humidity monitoring device, the unit is connected with the power supply and control module and is used for monitoring the temperature and humidity condition in the shell, and when the temperature and humidity exceed the threshold requirement, the power supply and control module controls the power off to terminate the test.
As a further scheme of the invention, the front side, the rear side, the left side and the right side of the standard current transformer are respectively provided with a vent hole for heat dissipation of the standard current transformer.
A method for carrying out segmented adaptive compensation by using the standard current transformer comprises the following steps: and segmenting the working current of the standard current transformer into N segments, wherein each segment corresponds to one compensation capacitor, the working current of the standard current transformer is identified through the power supply and control module, and the compensation capacitor is judged and selected.
As a further scheme of the invention, the error compensation unit of the standard current transformer is composed of N groups of compensation capacitors, N relays and a compensation winding, wherein the compensation winding is wound on an iron core, and the compensation capacitors and the relays are connected in series and then connected in parallel to the compensation winding; the control unit realizes the access of the compensation capacitor by controlling the switching of the relay, and the compensation accuracy is guaranteed.
As a further scheme of the invention, the secondary winding of the standard current transformer comprises a plurality of windings or taps K1-Km, the secondary winding and the primary winding L1-L2 form currents with a plurality of transformation ratios through excitation of an iron core, standard current transformation ratio information is input to the man-machine interaction unit, and the control unit controls switching of the relay to realize cascade connection and selection of the plurality of secondary windings, so that different transformation ratios are output.
The working principle of the invention is as follows:
when the overload capacity of the current transformer is tested, the primary winding and the secondary winding are connected with an up-flow power supply, a transformer calibrator, a voltage regulation control system and the tested current transformer in a current transformer test system through a wiring terminal row. The primary winding of the invention is connected with the primary winding of the tested current transformer and the output winding of the current rising power supply in series; the secondary winding is connected with a standard current signal terminal and a differential current signal terminal of a mutual inductor calibrator; the power supply and control module is connected with the voltage regulation control system, supplies power to the standard current transformer, and simultaneously feeds back the real-time primary and secondary current conditions and the temperature and humidity conditions of the standard current transformer to the voltage regulation control system. The standard current transformer and the tested current transformer of the invention work for 1 hour under 150% rated current, and the error of the tested current transformer is measured. The invention can provide a long-term accurate and stable standard current signal for the test, and can not cause error out-of-tolerance and even burn out equipment due to heat brought by long-term work.
During error test of the current transformer, the test wiring is the same as the above, the standard current transformer and the tested current transformer work at 1-120% rated current, and the error of the tested current transformer is measured. The invention can provide accurate and stable standard current signals for the test.
The invention relates to a high-precision multi-transformation-ratio standard current transformer capable of working for a long time under 150% rated current, which comprises: the device comprises a shell, a primary winding, a secondary winding, an air passage, an insulating film, an iron core, an error compensation unit, a power supply and control module, a human-computer interaction unit, a fan, a temperature and humidity monitoring device and a self-locking universal wheel. The primary winding and the secondary winding are wound on the iron core, and the secondary winding layers, the primary winding layers and the primary winding and the secondary winding are insulated by adopting diamond insulating films; the iron core, the primary winding, the secondary winding, the diamond insulating film and the air passage form a coil of the standard current transformer; the coil is used for transmitting and transforming current signals for the core of the standard current transformer; the air passages are used for increasing the heat dissipation capacity of the standard current transformer, the air passages are arranged between the primary windings and the secondary windings in a setting method as shown in figure 1, each layer of air passages are arranged in a staggered mode, and the heat dissipation effect is good. In the figure, gray is an iron core, black is a winding and white is an air channel; the human-computer interaction unit is embedded above the shell; the fan is used for increasing the gas flow in the standard current transformer and accelerating the heat dissipation of the standard current transformer; the temperature and humidity monitoring device is used for monitoring the temperature and humidity condition inside the standard current transformer, timely early warning the standard current transformer over-threshold working condition and improving the safety and accuracy of the test; the error compensation unit is used for compensating errors of all transformation ratios of the standard current transformer, so that the measurement accuracy of the standard current transformer in a wide current range is guaranteed; and the required control unit is used for communicating the standard current transformer with the outside and controlling the switching of the relay, so that the access of the compensation capacitor and the series selection of the secondary winding are realized.
While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes and modifications can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention.
Claims (9)
1. The utility model provides a high accuracy multiple transformation ratio standard current transformer of long term work under 150% rated current which characterized in that: the device comprises a shell, a primary winding, a secondary winding, an air passage, an insulating film, an iron core, an error compensation unit, a power supply and control module, a human-computer interaction unit, a fan, a self-locking universal wheel and a wiring terminal row;
the primary winding, the secondary winding, the air channel, the insulating film, the iron core, the error compensation unit, the power supply and control module and the fan are all positioned in the shell; the self-locking universal wheels are positioned at four corners of the bottom of the shell; the wiring terminal block is positioned above the shell, and the man-machine interaction unit is embedded above the shell;
the iron core of the standard current transformer is of an annular structure; a primary winding L1-L2 and a secondary winding K1-Km are uniformly wound on an iron core; the secondary winding layers, the primary winding layers and the primary winding and the secondary winding are insulated by adopting diamond insulating films; the iron core, the primary winding, the secondary winding, the diamond insulating film and the air passage form a coil of the standard current transformer, and the human-computer interaction unit is connected with the control module;
the error compensation unit of the standard current transformer consists of N groups of compensation capacitors, N relays and a compensation winding, wherein the compensation winding is wound on the iron core, and the compensation capacitors and the relays are connected in series and then connected in parallel to the compensation winding; the control unit realizes the access of the compensation capacitor by controlling the switching of the relay, and the compensation accuracy is guaranteed.
2. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the coil of the standard current transformer is provided with a plurality of layers of air passages, the coil is provided with a circle of air passages every N layers of windings, the air passages are wound on an iron core by a plurality of paper board strips with the width of x mm and the thickness of y mm, and the winding direction of the paper board strips is vertical to the winding direction of the windings; a plurality of cardboard strip evenly distributed is on the iron core.
3. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the paperboard strips of each layer of air passage are wound in a staggered mode, and the heat dissipation effect is further improved.
4. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the standard current transformer shell is of a cuboid structure.
5. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the standard current transformer's fan include into fan and air-out fan, the air-in fan sets up in standard current transformer casing front side board top, the air-out fan sets up in standard current transformer casing rear side board top, advance fan and air-out fan and be located same horizontal position, advance fan and air-out fan simultaneous working and form the wind channel, take away the heat of standard current transformer solenoid.
6. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the standard current transformer shell is further provided with a temperature and humidity monitoring device, the unit is connected with the power supply and control module and used for monitoring the temperature and humidity condition in the shell, and when the temperature and humidity exceed the threshold requirement, the power supply and control module controls the power-off and terminates the test.
7. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the front side, the rear side, the left side and the right side of the standard current transformer are provided with vent holes for heat dissipation of the standard current transformer.
8. The high-precision multi-transformation-ratio standard current transformer operating at 150% of rated current for a long time according to claim 1, wherein: the secondary winding of the standard current transformer comprises a plurality of windings or taps K1-Km, the secondary winding and the primary winding L1-L2 form currents with a plurality of transformation ratios through excitation of an iron core, standard current transformation ratio information is input to the man-machine interaction unit, and the control unit controls switching of the relay to realize cascade connection of the plurality of secondary windings in selection, so that different transformation ratios are output.
9. A method for performing piecewise adaptive compensation by using the standard current transformer according to any one of claims 1-8, comprising: and segmenting the working current of the standard current transformer into N segments, wherein each segment corresponds to one compensation capacitor, the working current of the standard current transformer is identified through the power supply and control module, and the compensation capacitor is judged and selected.
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| CN202011420185.3A CN112735755B (en) | 2020-12-07 | 2020-12-07 | High-precision multi-transformation-ratio standard current transformer working for long time at 150% rated current |
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| CN114823088B (en) * | 2022-06-23 | 2022-09-23 | 国网湖北省电力有限公司营销服务中心(计量中心) | Standard transformer and using method thereof |
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| CN1071025A (en) * | 1992-07-20 | 1993-04-14 | 章成铭 | Microminiature high-tension current (voltage) instrument transformer |
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