CN212514944U - Transformer core leakage current detection device based on PNI sensor - Google Patents

Abstract

The utility model discloses a transformer core leakage current detection device based on PNI sensors, which comprises two PNI sensors, a driving chip, a control module and a display module; the two PNI sensors are arranged on the same horizontal plane and are relatively fixed in position, the two PNI sensors are connected with the driving chip, and the driving chip, the control module and the display module are sequentially connected. The change of the leakage current strength of the transformer core is induced by the change of the magnetic field sensed by the two PNI sensors, the leakage current of the core at a certain moment is reflected to the magnitude of the magnetic field value of the core, and the corresponding leakage current of the core at the moment can be obtained by detecting the output magnetic field difference at the moment so as to evaluate the running state of the power transformer. The detection device can be used for monitoring in real time, has simple principle and high reliability, eliminates the influence of environmental stray magnetic fields, and has high detection precision and wide applicable range.

Description

Transformer core leakage current detection device based on PNI sensor

Technical Field

The utility model relates to a transformer state monitoring field especially relates to a current detection device is revealed to transformer core based on PNI sensor.

Background

The safe and reliable operation of electrical equipment is the premise of ensuring the safe operation of a power grid, among numerous electrical equipment, a transformer is undoubtedly a core device, the transformer is used as a node in the power grid and plays the roles of transmitting and distributing electric energy, once the transformer has a trip fault, the trend of the power grid tide is changed, the tidal current distribution is possibly uneven, local overvoltage is caused, the whole power grid can collapse in severe cases, large-area power failure accidents are caused, and the social and economic development is seriously influenced. Therefore, the safe operation of the transformer is effectively monitored, and the safety and reliability of the electric energy provided for users by the whole power grid are very important.

The current common method for detecting the leakage current of the transformer core comprises the following steps: the electromagnetic coil induction method comprises a handheld pincerlike mutual inductor and an automatic monitoring device; the Hall sensor detection method mainly converts a magnetic signal into an electric signal through a Hall sensor to measure the current. However, the above methods have their respective disadvantages. For example, in electromagnetic coil detection, due to the limitation of the material and the number of turns of a magnetic coil, the complete transmission of a magnetic field cannot be realized, and the deviation is large for detecting a weak magnetic field; the Hall sensor detection device is expensive, the influence on stray magnetic fields such as a geomagnetic field and the like cannot be completely eliminated, the popularization is not facilitated, the requirement on an operator is high, and an error can be caused by slight carelessness in operation.

SUMMERY OF THE UTILITY MODEL

The utility model provides a current detection device is revealed to transformer core based on PNI sensor to solve the current detection device and detect the not high problem of precision.

A transformer core leakage current detection device based on PNI sensors comprises two PNI sensors, a driving chip, a control module and a display module;

the two PNI sensors are arranged on the same horizontal plane and are relatively fixed in position, the two PNI sensors are connected with the driving chip, and the driving chip, the control module and the display module are sequentially connected.

When the detection device is used for detection, the two PNI sensors are placed in a manner that the horizontal direction of the PNI sensors is perpendicular to the transformer core, the drive chip transmits the magnetic field values detected by the two PNI sensors to the control module, the control module outputs corresponding current values to the display module according to the received difference value of the two magnetic field values, and the display module displays the leakage current of the transformer core in real time. The PNI sensor has small volume and high detection precision, and is suitable for weak magnetic field detection; two PNI sensors are placed perpendicular to the transformer core, so that the two PNI sensors are located in the same environmental magnetic field, the influence of an environmental stray magnetic field can be eliminated by calculating the magnetic field difference of the two detected magnetic field values, and then the corresponding current value is output according to the obtained magnetic field difference, so that the detection process of the leakage current of the transformer core is completed. The detection device can eliminate the influence of environmental stray magnetic fields and has high detection precision.

Further, the control module is an AT89C51 singlechip or a C52 singlechip.

Further, the display module is an LCD display screen or an LED display screen.

And the communication module is used for realizing the communication between the control module and the transformer substation monitoring center and can transmit the detected leakage current value of the transformer core to the transformer substation monitoring center.

Further, the communication module is a 4G module.

Further, the device also comprises an alarm module connected with the control module. When the detected leakage current value of the transformer core is larger than a set value, the control module sends an alarm instruction to the alarm module to control the alarm module to alarm.

The PNI sensor, the drive chip and the control module are embedded on the circuit substrate, and the circuit substrate is horizontally fixed in the box body. All inlay two PNI sensors, driver chip, control module on circuit substrate, be convenient for on the one hand ensure that two PNI sensors are in same horizontal plane, ensure to detect the precision, on the other hand guarantees the stability of connecting between each part of device, is fixed in the box body with the circuit substrate level, and the dismouting of detection device of can being convenient for can adapt to outdoor long-time detection operation simultaneously.

Advantageous effects

The utility model provides a current detection device is revealed to transformer core based on PNI sensor, the change that experiences magnetic field through two PNI sensors responds to transformer core and reveals the change of current intensity, reveals the size that the electric current reflected its magnetic field value with certain iron core constantly, just can obtain the iron core that corresponds this moment through detecting this output magnetic field difference constantly and reveal the electric current to aassessment power transformer's running state. The detection device can be used for monitoring in real time, has simple principle and high reliability, eliminates the influence of environmental stray magnetic fields, and has high detection precision and wide applicable range.

Drawings

Fig. 1 is a schematic structural diagram of a leakage current detection device for a transformer core according to an embodiment of the present invention;

fig. 2 is the embodiment of the utility model provides a transformer core leakage current detection device's singlechip and display circuit diagram.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "center", "longitudinal", "lateral", "vertical", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

As shown in fig. 1, the present embodiment provides a transformer core leakage current detection apparatus based on PNI sensors, which includes two PNI sensors 3, a driving chip 2, a control module 1, and a display module 4;

the two PNI sensors 3 are arranged on the same horizontal plane and are relatively fixed in position, the two PNI sensors 3 are connected with the driving chip 2, and the driving chip 2, the control module 1 and the display module 4 are sequentially connected.

When the detection device is used for detection, the two PNI sensors 3 are placed in a manner that the horizontal direction of the PNI sensors is perpendicular to the transformer core 5, the drive chip 2 transmits the magnetic field values detected by the two PNI sensors 3 to the control module 1, the control module 1 outputs the corresponding current values to the display module 4 according to the difference value of the received two magnetic field values, and the display module 4 displays the leakage current of the transformer core in real time. The PNI sensor has small volume and high detection precision, and is suitable for weak magnetic field detection; two PNI sensors 3 are placed perpendicular to the transformer core 5, so that the two PNI sensors 3 are located in the same environmental magnetic field, the influence of an environmental stray magnetic field can be eliminated by calculating the magnetic field difference of the two detected magnetic field values, and then the corresponding current value is output according to the obtained magnetic field difference, so that the detection process of the leakage current of the transformer core is completed. The detection device can eliminate the influence of environmental stray magnetic fields and has high detection precision.

In specific implementation, the control module 1 may select an AT89C51 single chip microcomputer or a C52 single chip microcomputer, and certainly in other embodiments, the control module 1 may also select an FPGA to implement; the display module 4 can select an LCD display screen or an LED display screen.

Optionally, the transformer core leakage current monitoring system further comprises a communication module (not shown) connected with the control module 1, the communication module can be a 4G module, the communication module is used for realizing communication between the control module 1 and a transformer substation monitoring center, and the detected transformer core leakage current value can be uploaded to the transformer substation monitoring center.

Optionally, the transformer core leakage current detection device further comprises an alarm module (not shown) connected with the control module 1, the alarm module can select a buzzer, and when the detected transformer core leakage current value is greater than a set value, the control module 1 sends an alarm instruction to the alarm module to control the alarm module to alarm.

When the PNI sensor is implemented, the PNI sensor comprises a circuit substrate and a box body (not shown), the two PNI sensors 3, the driving chip 2 and the control module 1 are embedded on the circuit substrate, the circuit substrate is horizontally fixed in the box body, and the box body can be a PVC box. With two PNI sensors 3, driver chip 2, control module 1 all inlays on circuit substrate, be convenient for on the one hand ensure that two PNI sensors 3 are in same horizontal plane, ensure to detect the precision, on the other hand guarantees the stability of connecting between each part of device, be fixed in the box body with the circuit substrate level, when detecting, fix the box body on transformer core through the fixation clamp, the dismouting of detection device of can being convenient for, can adapt to outdoor long-time detection operation simultaneously, guarantee simultaneously that two PNI sensors are fixed with transformer core's horizontal direction vertical distance, as 1 cm. The PNI sensor monitoring system further comprises a power supply module, wherein the power supply module is used for supplying power to the two PNI sensors, the driving chip, the control module, the display module, the communication module and the alarm module.

As shown in fig. 2, an AT89C51 single chip microcomputer is used as a control module, and an LCD display screen is used as a display module, which provides a single chip microcomputer and display circuit diagram of the transformer core leakage current detection device, wherein U3 represents the single chip microcomputer, pin 4 is an input terminal of a signal, pins 32 to 39 are connected to the LCD display screen, and P1 is connected to a power socket.

The principle of the present solution is further explained below. When the detection is carried out, the two PNI sensors are both in a composite magnetic field comprising an iron core magnetic field and an environment magnetic field, the result detected by each PNI sensor is the composite magnetic field value of the core magnetic field and the ambient magnetic field at the position of the PNI sensor, because the two PNI sensors are in the same ambient magnetic field, the two complex magnetic field values are subtracted, the influence of the environmental magnetic field can be eliminated, the obtained difference value is the difference between the iron core magnetic field value detected by one PNI sensor and the iron core magnetic field value detected by the other PNI sensor, the two magnetic field values follow the magnetic field distance attenuation rule, the relative positions of the two sensors are fixed, the attenuation rule becomes known quantity, the corresponding coefficient of the electromagnetic induction values of the magnetic field and the current is known, so that the size of the leakage current of the iron core can be obtained according to the corresponding coefficient of the electromagnetic induction values of the magnetic field and the current and the difference value of the two magnetic field values, and detection is realized. During implementation, a corresponding table of a difference value of magnetic field values detected by the two PNI sensors and leakage current of the transformer core can be generated in advance according to corresponding coefficients of electromagnetic induction values of a magnetic field and current and stored in the single chip microcomputer, and during detection, the single chip microcomputer can directly obtain a corresponding leakage current value of the transformer core according to the difference value of the magnetic field values detected by the two PNI sensors.

According to the transformer core leakage current detection device based on the PNI sensors, the change of the leakage current strength of the transformer core is sensed by the two PNI sensors through the change of the magnetic field, the core leakage current at a certain moment is reflected to the magnetic field value, and the corresponding core leakage current at the moment can be obtained by detecting the output magnetic field difference at the moment so as to evaluate the running state of the power transformer. The detection device can carry out real-time monitoring, has simple principle and high reliability, eliminates the influence of environmental stray magnetic fields, has high detection precision and wide applicable range; meanwhile, the device is simple and small and can adapt to outdoor long-time detection operation.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A transformer core leakage current detection device based on PNI sensors is characterized by comprising two PNI sensors, a driving chip, a control module and a display module;

the two PNI sensors are arranged on the same horizontal plane and are relatively fixed in position, the two PNI sensors are connected with the driving chip, and the driving chip, the control module and the display module are sequentially connected.

2. The transformer core leakage current detection device based on the PNI sensor as recited in claim 1, wherein said control module is an AT89C51 single chip microcomputer or a C52 single chip microcomputer.

3. The PNI sensor-based transformer core leakage current detection device as recited in claim 1, wherein the display module is an LCD display screen or an LED display screen.

4. The PNI sensor-based transformer core leakage current detection apparatus according to claim 1, further comprising a communication module connected to the control module.

5. The PNI sensor-based transformer core leakage current detection device of claim 4, wherein the communication module is a 4G module.

6. The PNI sensor-based transformer core leakage current detection apparatus according to claim 1, further comprising an alarm module connected to the control module.

7. The PNI sensor-based transformer core leakage current detection device according to claim 1, further comprising a circuit substrate and a box body, wherein the two PNI sensors, the driving chip and the control module are embedded on the circuit substrate, and the circuit substrate is horizontally fixed in the box body.

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