Search

CN-121762904-B - Dynamic frequency-dependent tracking electrified detection device

CN121762904BCN 121762904 BCN121762904 BCN 121762904BCN-121762904-B

Abstract

The invention belongs to the technical field of electric power system experiments, and discloses a dynamic frequency-dependent tracking live detection device which comprises a main control module, a double-differential electric field coupling module, an ultrahigh-resistance steady-state acquisition module, a differential amplification and signal conditioning module and a steady-state discrimination module. According to the invention, the ultra-high resistance steady-state maintaining structure is introduced into the electric field coupling end to inhibit the release of coupling charges, so that the coupling potential formed by the space electrostatic field under ultra-low frequency and quasi-static conditions can exist stably, and the reliable identification of the direct current and ultra-low frequency band electric state is realized.

Inventors

  • ZHANG HAO
  • JIANG LIAN
  • MA SIQIAN
  • Pang dan
  • LI ZHI
  • WANG AN

Assignees

  • 国网吉林省电力有限公司长春供电公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (9)

  1. 1. The dynamic frequency-dependent tracking live detection device comprises a wireless communication module, an audible and visual alarm module, a mounting base and a protective shell, and is characterized by also comprising a main control module, a double-differential electric field coupling module, an ultrahigh-resistance steady-state acquisition module, a differential amplification and signal conditioning module and a steady-state discrimination module; the double-differential electric field coupling module is used for forming more than two groups of coupling potential signals with different spatial positions under the action of the space electrostatic field around the tested conductor; the ultra-high resistance steady-state acquisition module is connected with the double-differential electric field coupling module and is used for inhibiting the release of coupled charges and keeping the steady-state existence of coupled potential signals under the condition of an ultra-low frequency or quasi-static electric field; The differential amplification and signal conditioning module is connected with the ultra-high resistance steady-state acquisition module and is used for carrying out differential enhancement and low-frequency processing on steady-state coupling potential signals; The steady state judging module is connected with the differential amplification and signal conditioning module and is used for outputting the electrified state of the tested conductor according to the time stability characteristic of the steady state coupling potential signal; The main control module is respectively and electrically connected with the differential amplification and signal conditioning module, the steady state judging module, the wireless communication module and the audible and visual alarm module and is used for data processing, logic control and instruction issuing; the double-differential electric field coupling module comprises more than four electric field coupling electrodes, wherein the electric field coupling electrodes form two groups of differential electrode pairs which are oppositely arranged in space, each differential electrode pair is used for inducing coupling potential formed by the space electrostatic field around a tested conductor at different positions, and the unbalanced distribution characteristic of the space electrostatic field is represented by the steady-state potential difference between each differential electrode pair.
  2. 2. The device of claim 1, wherein the ultra-high impedance steady-state acquisition module comprises an ultra-high impedance pre-holding structure, wherein the equivalent input impedance is higher than 10 13 omega, and the ultra-high impedance pre-holding structure is arranged at the output end of the electric field coupling electrode and cooperates with the double differential electrodes to stably hold the spatial unbalanced coupling potential in an ultra-low frequency time scale.
  3. 3. The device for detecting the dynamic frequency-dependent tracking electrification of the amplifier according to claim 1, wherein the ultra-high-resistance steady-state acquisition module further comprises an input protection diode, and the ultra-high-resistance steady-state acquisition module is connected in parallel to two sides of an input end of the amplifier by adopting a dual series diode with a withstand voltage of 85V so as to realize protection against transient overvoltage.
  4. 4. The apparatus of claim 1, wherein the differential amplifying and signal conditioning module is configured in a low-frequency or ultra-low-frequency operation mode, and the upper limit of the passband is lower than 5Hz, so as to suppress interference signals in frequency bands of power frequency and above while maintaining steady coupling potential information.
  5. 5. The device for detecting the dynamic frequency-dependent tracking electrification of claim 1, wherein the steady state judging module judges based on the amplitude stability, the change slope and the statistical fluctuation characteristics of the steady state coupling potential signal in a preset time window, and outputs a judging result of the electrified state of the tested conductor when the steady state coupling potential signal meets the stability criterion in the time window.
  6. 6. The dynamic frequency-dependent tracking electrified detection device according to claim 1 is characterized in that the electric field coupling electrode is a nickel-plated copper sheet, is 150-degree arc-shaped, is 50mm in height, 30mm in radius and 1mm in thickness, the two differential electrodes are symmetrically arranged on the mounting base, the electrode spacing is 2mm, the surface of the electrode is subjected to passivation treatment, the edge of the electrode adopts a R2mm round corner design, epoxy resin LEDOO 6060 insulating medium is filled inside the electrode, and the relative positions of the four electrodes are fixed through an insulating support integrally formed by epoxy resin.
  7. 7. The device for detecting dynamic frequency-dependent tracking electrification of a human body according to claim 2, wherein the ultra-high impedance pre-holding structure comprises a leakage suppression resistor pre-circuit, the leakage suppression resistor pre-circuit is a pre-in-phase circuit formed by a 10 14 ohm ultra-high impedance chip, and the pre-in-phase circuit is connected in series between the output ends of the electrodes and the input end of the differential amplifier, so that equivalent input impedance is ensured to be not lower than 10 13 ohm.
  8. 8. The dynamic frequency-dependent tracking live detection device according to claim 4 is characterized in that a differential amplifier in the differential amplification and signal conditioning module adopts a two-stage amplification structure, the primary amplification factor is 10 times, the secondary amplification factor is 10-100 times, the total differential gain A_d=100-1000 times, a filter circuit adopts a 2-order RC low-pass filter structure, the cut-off frequency is 0.5Hz, and the differential amplifier is configured with input impedance of more than or equal to 10GΩ, input bias current of less than or equal to 3pA and equivalent noise voltage of less than or equal to 10nV/Hz.
  9. 9. An ultralow frequency non-contact electricity test method based on double differential coupling is characterized by applying the dynamic frequency-dependent tracking electrification detection device as set forth in any one of claims 1-8, The device is installed, wherein the device is fixed at a position 20-30 cm away from a tested conductor through an installation base, the device is adjusted to enable the double differential electrodes to be opposite to the tested conductor, and self-inspection is completed after a power supply is connected; The second step of signal coupling, namely, an electrostatic field formed by a tested conductor acts on a double differential electrode, an upper outer electrode and an upper inner electrode generate a first differential signal Vd1= (k 1 -k 2 ) Vm, a lower outer electrode and a lower inner electrode generate a second differential signal Vd2= (k 3 -k 4 ) Vm, wherein k 1 、k 2 、k 3 、k 4 is the coupling coefficient of four electrodes respectively, and Vm is the potential of the tested conductor in a charged state; The differential amplifier amplifies a mu V level differential signal to mV level, and the differential signal is output to a main control module after power frequency and above frequency band interference is removed by 2-order RC low-pass filtering; The ADC unit of the main control module collects amplified signals at the speed of 200SPS, suppresses power frequency interference through the IIR filter unit, and the multidimensional criterion unit outputs three states of electrification, non-electrification and abnormal interference through variance calculation, slope analysis, time window consistency judgment and interference identification; And fifthly, warning and communication, namely starting an audible and visual alarm module if the power is judged to be on, pushing the power information to a background system by a wireless communication module, and continuously alarming by an LED lamp and a buzzer if the power is judged to be abnormal, and prompting to check an interference source.

Description

Dynamic frequency-dependent tracking electrified detection device Technical Field The invention belongs to the technical field of electric power system experiments, and particularly relates to an ultralow frequency-oriented non-contact live detection device suitable for high-voltage transmission, ultralow frequency voltage withstand test of a cable, unattended transformer substation and other scenes. Background With the rapid development of the power industry, the direct-current ultra-high voltage technology is widely applied, the ultra-low frequency withstand voltage test is increasingly important in the detection of power equipment, and the electricity testing device is used as core equipment for the safety operation of a power system, and the performance of the electricity testing device is directly related to the safety of operators and the running stability of the equipment. The core function of the electricity checking device is to provide safety warning for operators by detecting the electrified state of the conductor, so as to avoid electric shock and equipment damage accidents. Meanwhile, in ultra-low frequency and quasi-static electric fields, only extremely weak static coupling charges are formed between the electrodes and the tested conductor, and any input impedance lower than 1012 omega can lead to rapid release of the coupling charges (tau=rin and Ceq) within a time constant, so that the output of the sensor is close to zero, and a distinguishable signal cannot be formed. The scenes such as transformer substations, convertor stations and the like have power frequency common mode interference (the 50Hz electric field intensity can reach 10 kV/M), corona discharge noise and high-frequency radio interference, the traditional single electrode structure has no common mode inhibition capability, the input impedance is insufficient (generally lower than 100MΩ), mu V-level weak coupling signals cannot be ensured, the influence of space stray electric fields is easy to cause, the signal drift and the misjudgment rate are high, and stable and reliable detection results cannot be output. In addition, part of the non-contact electricity testing device depends on human body or external ground as reference, has limited detection distance and strong directivity, has insufficient operation safety margin in GIS equipment, high-altitude lines and unattended scenes, and is difficult to meet the actual requirements of electricity testing of direct current and ultra-low frequency power equipment. Therefore, it is necessary to design a non-contact electroscope device which is suitable for ultra-low frequency scenes, has strong anti-interference capability, long detection distance and convenient operation, so as to solve the defects in the prior art. Disclosure of Invention The technical problem to be solved by the invention is to provide the dynamic frequency-dependent tracking electrified detection device, which inhibits the release of coupling charges (meeting τ not less than 1/(2 f)) by introducing the ultra-high resistance steady-state maintaining structure at the electric field coupling end, so that the coupling potential formed by the space electrostatic field under the ultra-low frequency and quasi-static conditions can be stably present, thereby realizing the reliable identification of the electric state of direct current and 0.1 Hz-1 Hz ultra-low frequency bands and improving the electricity testing safety and reliability under the complex electric power operation environment. The dynamic frequency-dependent tracking live detection device comprises a wireless communication module, an audible and visual alarm module, a mounting base, a protective shell, a main control module, a double-differential electric field coupling module, an ultrahigh-resistance steady-state acquisition module, a differential amplification and signal conditioning module and a steady-state judging module, wherein the main control module is used for controlling the power supply of the device; the double-differential electric field coupling module is used for forming more than two groups of coupling potential signals with different spatial positions under the action of the space electrostatic field around the tested conductor; the ultra-high resistance steady-state acquisition module is connected with the double-differential electric field coupling module and is used for inhibiting the release of coupled charges and keeping the steady-state existence of coupled potential signals under the condition of an ultra-low frequency or quasi-static electric field; The differential amplification and signal conditioning module is connected with the ultra-high resistance steady-state acquisition module and is used for carrying out differential enhancement and low-frequency processing on steady-state coupling potential signals; The steady state judging module is connected with the differential amplification and signal conditioning module and is use