CN-121978578-A - Transformer core grounding current detection device and detection method thereof

CN121978578ACN 121978578 ACN121978578 ACN 121978578ACN-121978578-A

Abstract

The invention relates to the technical field of grounding current detection devices, the method comprises the following steps: the transformer core grounding current detection device comprises a detection unit, a signal processing unit, a self-checking and calibrating unit, a control analysis unit, a data transmission unit, a power supply unit and a display alarm unit, wherein the units are integrally packaged and adopt an integrated metal shielding structure for grounding treatment so as to inhibit electromagnetic interference. The self-checking and calibrating unit can realize real-time self-checking and periodic automatic calibration of each module, does not need manual frequent intervention, can timely find module faults and accurately position, reduces manual maintenance workload, and simultaneously ensures the detection precision of long-term operation of the device.

Inventors

YU GANG
MA HONGGE
GENG CHANGCHANG
KANG XIN
WANG XUAN
YU NANA
YU JIALE

Assignees

保定市子盛电气设备制造有限公司

Dates

Publication Date: 20260505
Application Date: 20260203

Claims (9)

1. The grounding current detection device (1) of the transformer iron core is characterized by comprising a detection unit, a signal processing unit, a self-checking and calibrating unit, a control analysis unit, a data transmission unit, a power supply unit and a display alarm unit, wherein the units are integrally packaged and adopt an integrated metal shielding structure for grounding treatment so as to inhibit electromagnetic interference; The detection unit adopts a double-sensor fusion structure of a Rogowski coil and a Hall sensor, and realizes full-range acquisition of the grounding current of the iron core by combining a self-adaptive weighting fusion algorithm; The signal processing unit adopts a multi-stage processing structure of self-adaptive filtering, programmable gain amplification, isolation conversion and signal conditioning, and is used for eliminating interference and completing signal conversion; the self-checking and calibrating unit integrates a built-in standard signal source to realize real-time self-checking, periodic automatic calibration and fault positioning of each module; the control analysis unit adopts a dual-core architecture, integrates a dynamic threshold correction algorithm, and distinguishes different working conditions and fault severity of the grounding of the iron core; the data transmission unit adopts a dual-mode anti-interference transmission mode and combines data encryption and breakpoint continuous transmission technology to realize data transmission; the display alarm unit combines the functions of display, audible and visual alarm and local operation, and realizes state feedback and local operation and maintenance.
2. The transformer core grounding current detection device according to claim 1 is characterized in that a Rogowski coil is of a hollow annular structure, the number of turns is 1000-2000, the inner diameter is 50-80 mm, a small-diameter enameled copper wire is adopted for winding, a closed-loop Hall current sensor is selected as a Hall sensor, and a self-adaptive weighting fusion algorithm dynamically adjusts the weighting coefficients of two paths of signals by calculating the noise variance of the signals acquired by the two paths of sensors in real time, so that the full-range grounding current is acquired.
3. The transformer core grounding current detection device according to claim 2 is characterized in that the signal processing unit comprises a signal conditioning module, an adaptive filtering module, a programmable gain amplifier and an isolation conversion module, wherein the signal conditioning module is used for realizing current and voltage signal conversion by adopting resistors and is matched with a high input impedance operational amplifier to form a voltage follower so as to realize signal impedance matching and distortion-free transmission, the adaptive filtering module is used for realizing at least 20-order active filtering structure, the amplification factor of the programmable gain amplifier is adjustable within a range of 1-1000 times and is used for adapting signals with different amplitudes, and the isolation conversion module is used for at least 16-bit AD converter.
4. The device for detecting the grounding current of the transformer core according to claim 3, wherein the built-in standard signal source of the self-checking calibration unit can generate standard current signals within the range of 0-10A and 50 Hz-1 kHz, and in the calibration process, a calibration coefficient is obtained by calculating the ratio of the standard signal value to the actual detection value of the device, and the detection data is corrected by using the calibration coefficient.
5. The transformer core grounding current detection device according to claim 4, wherein the dual-core architecture of the control analysis unit consists of a main control chip and a special data processing chip, wherein the main control chip is a 32-bit single chip microcomputer, the special data processing chip is a high-speed digital signal processing chip, the dynamic threshold correction algorithm is combined with three key working condition parameters of environment temperature, transformer load and power grid frequency, and the fault judgment threshold is adjusted in real time through a preset correction formula.
6. The transformer core grounding current detection device according to claim 5, wherein the dual-mode anti-interference transmission mode of the data transmission unit adopts a mode of combining high-speed wireless communication with long-distance wireless communication to realize real-time transmission and long-distance backup transmission of data, the data encryption technology adopts a hardware encryption mode, and the dual-mode switching is automatically triggered according to the signal intensity of a main communication mode.
7. The transformer core grounding current detection device according to claim 6, wherein the dual-mode power supply structure of the power supply unit adopts a mode of combining a direct-current power supply of a transformer substation with solar power supply, wherein the input voltage range of the direct-current power supply is adapted to the conventional direct-current power supply specification of the transformer substation, the solar power supply part is matched with the solar charging management module and the energy storage module to realize electric energy storage and power supply, the power supply protection function comprises overcurrent, overvoltage, short circuit and reverse connection quadruple protection, and the low-power consumption management function automatically adjusts the power supply according to the working state of the device.
8. The transformer core grounding current detection device according to claim 7, wherein the display alarm unit comprises an audible and visual alarm module and a display module, the display module is a liquid crystal display screen, the display module displays detection data, working states and fault information, the audible and visual alarm module distinguishes different alarm modes according to the severity of the fault, and the local operation function is realized through a special key to complete parameter debugging, fault resetting and self-checking to trigger local operation and maintenance operation.
9. The method for detecting the grounding current of the transformer core is characterized by comprising the following steps of: after the device is electrified and initialized, the self-inspection of the whole module is finished, and the device enters a detection state if no fault exists; The method comprises the steps of collecting an iron core grounding current signal through double-sensor fusion, processing the iron core grounding current signal through a signal processing unit and transmitting the iron core grounding current signal to a control analysis unit; the control analysis unit analyzes and calculates the signals, and judges the grounding working condition and the fault level by combining the dynamic threshold value; the encryption transmission and the real-time state feedback of the detection data and the fault information are synchronously completed; and (3) automatic calibration is executed regularly, and the ground current is detected in real time and fault early warning is realized through continuous circulation.

Description

Transformer core grounding current detection device and detection method thereof Technical Field The invention relates to the technical field of current detection devices, in particular to a transformer core grounding current detection device and a detection method thereof. Background The transformer is core equipment for energy conversion and transmission in the power system, and the operation reliability of the transformer directly determines the safe and stable operation of the power grid. The transformer iron core is formed by stacking silicon steel sheets, an insulating layer exists between the silicon steel sheets, and in normal operation, the iron core needs to be grounded through a single point of a grounding lead wire, so that the purpose is to eliminate the floating potential of the iron core to the ground, and the iron core is prevented from being damaged due to the fact that the floating potential is too high to break through the iron core insulation. In the long-term operation process of the transformer, the insulation between the iron core sheets is easy to break due to the influence of vibration, insulation aging, oil quality degradation, foreign matter invasion and other factors, so that the iron core has multipoint grounding faults. When the iron core is grounded in multiple points, larger grounding current can be generated in the grounding lead, the current flows through the iron core to form a closed loop, the iron core is locally overheated, insulation aging is accelerated, the iron core and windings can be burnt out in severe cases, the transformer is stopped, and the power grid accident is caused, so that the grounding current of the iron core of the transformer is detected in real time and accurately, and the multipoint grounding fault is found in time, so that the method has important practical significance. At present, the existing transformer core grounding current detection device has the following defects that the detection precision is low, a single sensor is adopted to collect grounding current signals, the detection precision is influenced by complex electromagnetic interference and temperature fluctuation of a transformer substation, the detection error is large, weak grounding current signals (< 10 mA) cannot be captured, early-stage mild multipoint grounding faults are difficult to find, the fault judgment accuracy is poor, the fault judgment is carried out by adopting a fixed threshold value, the dynamic adjustment of the operation working conditions (environment temperature, power grid frequency and load) of the transformer is not combined, false alarm and missing alarm phenomena are easy to occur, and the severity of the faults cannot be distinguished. Disclosure of Invention Aiming at the technical problems of the prior transformer core grounding current detection device provided in the background art, the invention provides a transformer core grounding current detection device and a detection method thereof. The technical scheme includes that the grounding current detection device of the transformer core comprises a detection unit, a signal processing unit, a self-checking calibration unit, a control analysis unit, a data transmission unit, a power supply unit and a display alarm unit, wherein the detection unit, the signal processing unit, the self-checking calibration unit, the control analysis unit, the data transmission unit, the power supply unit and the display alarm unit are integrally packaged and adopt an integrated metal shielding structure for grounding treatment to inhibit electromagnetic interference, the detection unit adopts a double-sensor fusion structure of a Rogowski coil and a Hall sensor and combines an adaptive weighting fusion algorithm to realize full-range acquisition of the grounding current of the core, the signal processing unit adopts a multi-stage treatment structure for adaptive filtering, programmable gain amplification, isolation conversion and signal conditioning to eliminate interference and complete signal conversion, and the self-checking calibration unit integrates a built-in standard signal source to realize real-time self-checking of each module, The system comprises a control analysis unit, a data transmission unit, a power supply unit, a display alarm unit, a local operation and maintenance unit, a dual-mode anti-interference transmission mode, a data encryption and breakpoint continuous transmission technology, a dual-mode power supply structure, a power supply protection and low-power consumption management function and a display alarm unit, wherein the control analysis unit adopts a dual-core structure and integrates a dynamic threshold correction algorithm to distinguish different working conditions of iron core grounding and fault severity, the data transmission unit adopts a dual-mode anti-interference transmission mode and integrates the data encryption and breakpoint continuous transmission technology to realize stabl