CN109342906B - Multifunctional partial discharge detection system and method - Google Patents

Abstract

The utility model discloses a multifunctional partial discharge detection system and a method, which can carry out fault degree evaluation, fault position analysis and fault type preliminary identification according to the comparison of the amplitude, phase and original signal characteristics of received ultrahigh frequency signals, pulse signals and ultrasonic signals with background signals and the analysis of the relevant characteristics with power frequency; when waiting to examine equipment contact in time, utilize extension mechanism to extend, make the host computer press close to or contact and wait to examine equipment, this disclosure conveniently carries out partial discharge and detects.

Description

Multifunctional partial discharge detection system and method

Technical Field

The disclosure relates to a multifunctional partial discharge detection system and method.

Background

In the operation of electrical installations, partial discharges are discharges which do not completely bridge the electrodes, usually to a small extent, but this process of accumulation ultimately leads to damage to the insulation, which has the effect of not only causing a power outage, but also endangering personnel safety.

Disclosure of Invention

In order to solve the above problems, the present disclosure provides a multifunctional partial discharge detection system and method, which facilitate partial discharge detection.

In order to achieve the purpose, the following technical scheme is adopted in the disclosure:

a multifunctional partial discharge detection device comprises a host and a detector body connected with the host, wherein the detector body comprises:

the ultrahigh frequency signal acquisition module is arranged at the disc insulator outside the GIS body and is configured to detect an ultrahigh frequency signal excited by partial discharge inside the disc insulator outside the GIS body;

the high-frequency current signal acquisition module is arranged on the cable grounding wire and is configured to detect a pulse signal emitted from a partial discharge point and carry out coupling output;

an AE sensor configured to detect an ultrasonic signal of a surface of the transformer case or body;

the host receives the ultrahigh frequency signal, the pulse signal and the ultrasonic signal, and is configured to perform fault degree evaluation, fault position analysis and fault type preliminary identification according to the comparison of the amplitude, the phase and the original signal characteristics of the received signal with the background signal and the analysis of the relevant characteristics of the received signal and the power frequency.

As further limitation, an Ultra sensor and a TEV sensor are arranged in the host, an LEMO interface in signal connection with an AE sensor is arranged on the host, and an Audio interface, a USB interface, a Power interface and an Ant interface are arranged at the bottom of the host, wherein the Audio interface and the USB interface are used for being connected with an Ultra channel monitoring earphone, the Power interface is connected with an external Power supply, and the Ant interface is used for being connected with an external antenna of a synchronous Power supply wireless trigger.

As a further limitation, the high-frequency current signal sensor is directly clamped on a cable ground wire to detect a pulse signal emitted from a partial discharge point, the pulse signal is coupled and output, and the host computer receives the output and then carries out real-time monitoring and analysis.

As a further limitation, the host is provided with an input key to control the switching action of the host.

A multifunctional partial discharge detection system comprises the device and an extension mechanism, wherein the extension mechanism comprises a support box, a support block, a finger pressing unit and an extension rod, the support box and the support block are arranged up and down, the extension rod is arranged between the support box and the support block, a support plate is arranged above the support box, the finger pressing unit is arranged between the support plate and the support block, and the finger pressing unit is used for pressing to control a host.

As a further limitation, the extension rod and the support box as well as the extension rod and the support block are hinged, the extension rod, the support box and the support block form a parallelogram link mechanism, a positioning plate is arranged on the support block, and a positioning bolt is arranged between the positioning plate and one of the extension rods.

As a further limitation, the finger pressing unit comprises a finger pressing block made of silica gel and arranged at the bottom of the supporting plate in a sliding manner, a spring arranged between the finger pressing block and the supporting plate, a first wire wheel arranged on the supporting plate, a second wire wheel arranged on the supporting plate, a knob fixed on the second wire wheel, and a torsion spring arranged between the second wire wheel and the supporting plate, wherein a pull wire is arranged between the finger pressing block and the outer wall of the second wire wheel and is in contact with the first wire wheel; under the action of the spring, a gap is formed between the pressing block and the supporting box, and the spring is always in a compressed state.

As a further limitation, the bottom of the supporting plate is provided with a sliding groove, and the finger pressing block is in sliding connection with the sliding groove; the top of the supporting plate is provided with a spring groove, the upper part of the spring groove is provided with a positioning ring, and the spring is arranged in the spring groove.

Based on the working method of the system, the host machine is utilized to carry out fault degree evaluation, fault position analysis and fault type preliminary identification according to the comparison of the amplitude, phase and original signal characteristics of the received ultrahigh frequency signal, pulse signal and ultrasonic signal with the background signal and the analysis of the relevant characteristics with the power frequency;

when the equipment to be detected is not contactable, the extension mechanism is utilized to extend, so that the host machine is close to or contacts the equipment to be detected.

Further, the signal is analyzed by a TEV transverse analysis method, a TEV constant value discrimination method, or a longitudinal analysis method.

Compared with the prior art, the beneficial effect of this disclosure is:

according to the method, when the equipment to be detected (such as a switch cabinet) is in touch with hands, a detector can hold a host to directly detect; when waiting to detect equipment manpower can not touch in time, the tray can be handed to the operator to place the host computer on holding in the palm the box, then swing the outer pole of stretching out and make and hold in the palm the box and arrange suitable high position in, and make the host computer press close to or contact and wait to detect equipment, can conveniently carry out partial discharge and detect.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is a schematic front view of a mainframe of the present disclosure;

FIG. 2 is a top view of the mainframe of the present disclosure;

FIG. 3 is a bottom view of the mainframe of the present disclosure;

FIG. 4 is a side schematic view of a mainframe of the present disclosure;

FIG. 5 is a schematic illustration of the present disclosure as tested;

FIG. 6 is a schematic view of the stretching mechanism;

FIG. 7 is a top view of the tray;

FIG. 8 is a schematic view of a finger pressing unit;

FIG. 9 is a schematic view of the placement of a first ear plate on top of an upper plate;

in the figure: the main frame, 11 display screens, 12 switches, 13 sensor detection ports, 14Audio interfaces, 15USB interfaces, 16Power interfaces, 17Ant interfaces, 18LEMO interfaces, 2 support boxes, 21 main frame grooves, 22 through holes, 23 avoiding grooves, 24 support rods, 25 upper plates, 251 spring grooves, 252 positioning rings, 253 sliding grooves, 26 transverse rods, 27 first lug plates, 28 first wire wheels, 29 pull wires, 3 support blocks, 31 extending rods, 32 positioning bolts, 33 positioning plates, 34 second lug plates, 35 second wire wheels, 36 knobs, 37 displays, 4 finger pressing blocks and 41 springs.

The specific implementation mode is as follows:

the present disclosure is further described with reference to the following drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only relational terms determined for convenience in describing structural relationships of the parts or elements of the present disclosure, and do not refer to any parts or elements of the present disclosure, and are not to be construed as limiting the present disclosure.

In the present disclosure, terms such as "fixedly connected", "connected", and the like are to be understood in a broad sense, and mean either a fixed connection or an integrally connected or detachable connection; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present disclosure can be determined on a case-by-case basis by persons skilled in the relevant art or technicians, and are not to be construed as limitations of the present disclosure.

As shown in fig. 1 to 5, the multifunctional partial discharge detector mainly includes a host 1, an Ultra-high frequency signal acquisition module, a high-frequency current signal acquisition module, an AE sensor, an Ultra-high frequency signal sensor, a high-frequency current signal sensor, an Ultra channel monitoring earphone, a USB data line, and a synchronous power supply wireless trigger, and the following describes each component and the working principle of the present invention in detail with reference to the attached drawings.

Partial discharges are discharges which do not completely bridge the electrodes, usually to a small extent, but this process of continuing accumulation ultimately also leads to damage to the insulating layer, the effect of which is not only a power outage, but also a risk to personnel. Partial discharges generally release energy in the form of: (1) electromagnetic form: radio waves/light/heat; (2) acoustic wave form: sound/ultrasound; (3) gas form: ozone/nitrous oxide. The invention mainly realizes the detection of the partial discharge through the detection of electromagnetic waves or/and ultrasonic waves.

As shown in fig. 1, the main machine 1 has an insulating housing, and a display screen 11 and a switch 12 are arranged on the main machine, wherein the display screen is a touch screen, an Ultra sensor and a TEV sensor are arranged in the main machine, the Ultra sensor and the TEV sensor detect through a sensor detection port 13, sound waves generated by partial discharge are scattered in each frequency band, and audible sound wave detection depends on the hearing of an individual, so the Ultra sensor is adopted to detect the sound waves in the invention, and the invention has the following advantages: the Ultra sensor is more sensitive than a human ear, independent of the operator's level of operation and above the audible frequency range, and directional. As shown in fig. 4, an LEMO interface 18 is provided on the right side of the host for connection to an AE sensor.

When partial discharges occur within a switchgear, such as a switchgear cabinet, electromagnetic waves are generated that can only propagate out through the passages between the metal enclosures of the switchgear cabinet, which may be spaces, gaskets, or other insulating parts between the metal enclosures. When the electromagnetic wave is transmitted out of the metal box body, a transient voltage To Earth (TEV) is generated on the metal box body of the switch cabinet, and the transient voltage To Earth (TEV) is only a few volts and can only be maintained for a time of a few nanoseconds (ns). For this purpose, partial discharges in the switchgear can be tested by placing a TEV sensor on the metal housing of the switchgear in operation.

Ultra high frequency signal sensor (UHF sensor): when partial discharge is generated inside the GIS equipment, the generated ultrahigh frequency electromagnetic wave signal is transmitted along the GIS cavity. Disc insulators are installed between connecting flanges inside GIS equipment, so that a gap which is not shielded for electromagnetic waves exists between metal flanges. When the ultrahigh frequency signal in the GIS is transmitted to the disc insulator, part of the signal is radiated to the outside of the GIS equipment through the gap, and the width of the gap can not have decisive influence on the radiation intensity. Therefore, the ultrahigh frequency signal sensor is arranged at the disc insulator outside the GIS body, and the ultrahigh frequency signal excited by the local discharge inside the GIS body can be detected.

High frequency current signal sensor (HFCT sensor): when the power cable generates partial discharge, a high-frequency pulse signal and an ultrasonic signal are generally excited. The frequency of the high-frequency pulse signal is generally above 300kHz, the high-frequency pulse signal can be transmitted in a loop of a cable line, the HFCT sensor is directly clamped on a cable grounding wire to detect the pulse signal emitted from a partial discharge point, the pulse signal is coupled and output, and analysis equipment is used for real-time monitoring and analysis. Because the partial discharge pulse current can flow through the grounding wire, the high-frequency current signal sensor is clamped on the grounding wire of the cable, and a high-frequency discharge signal can be detected from the high-frequency current signal sensor.

AE sensor: when the partial discharge phenomenon occurs, the molecules collide violently and macroscopically form a pressure instantly to generate ultrasonic pulses, ultrasonic signals with the frequency of 10kHz-200kHz transmitted along the shell can be received by being tightly attached to the surface of a GIS, a cable or a transformer shell or a body, and fault degree evaluation, fault position analysis and fault type preliminary identification can be performed according to the comparison of the amplitude, the phase and the original signal characteristics of the received signals and background signals and the analysis of the relevant characteristics of power frequency. The acoustic method is non-invasive and less influenced by external electromagnetic noise, and is an ideal field detection method. When the AE sensor is used for measurement, the AE sensor cannot be directly arranged on the surface of a cable accessory, and in order to prevent personal safety, the partial discharge of the cable is detected by adopting a mode of combining a waveguide rod and an ultrasonic sensor.

The host computer embeds TEV sensor and Ultra sensor, and the right side of host computer is equipped with the LEMO interface, and multiplexing AE sensor and Ultra sensor. As shown in fig. 3, four interfaces are provided at the bottom of the host, respectively: (1) the Audio interface is used for connecting an Ultra channel monitoring earphone and monitoring signals received by the Ultra sensor; (2) the USB interface transmits the data measured by the equipment to a computer or a mobile phone through the USB interface and a USB data line; (3) the Power interface is connected with an external Power supply for charging, a matched charger is adopted for charging, an indicator lamp on the charger is red when the charger is not fully charged, and the indicator lamp is green when the charger is fully charged; (4) and the Ant interface is used for being connected with an external antenna of the synchronous power supply wireless trigger.

Synchronous power supply wireless trigger:

the synchronous power supply wireless trigger can be connected with a two-hole socket of a common patch board or a cable reel, a blue indicator lamp is arranged on the trigger, and blue light indication can be realized after the trigger is electrified; when the antenna is applied on site, the antenna can be externally connected according to actual conditions. The lithium battery is further arranged in the host, and the host is charged through the charger. (1) When the battery icon of the host computer turns red or the host computer is not bright, a user needs to charge the host computer in time and uses a charger (12.6V/1A) matched with the equipment to charge the host computer, and the charger is provided with a charging indicator light, is red when not full of the battery and is green when full of the battery; (2) when the electric quantity indicator lamp of the module turns red, a user needs to charge the host in time; a charger (8.4V/1A) is used for charging the module, a charging indicator lamp is arranged on the charger, the charger is red when not full of the charger and is green when full of the charger; (3) when the host or the module is not used for a long time, the host or the module is charged every three months, so that the built-in lithium battery is prevented from being scrapped due to voltage loss. When the host or the module is in a charging state, the partial discharge test is not required to be carried out, and the equipment is in a shutdown state.

When the host is in a power-off state, the display screen can be immediately lightened by pressing the switch 12 on the host, and simultaneously, a 'tic' sound is sent to indicate that the power supply is turned on, a self-checking information interface appears on the display screen for about 3 seconds, the screen is clicked within the 3 seconds to automatically enter a touch screen calibration function, and a main interface is displayed without a touch automatic skipping mark.

When the host is in a power-on state, the switch 12 on the host is pressed, the host is internally provided with a power-on delay function (damage to internal devices due to quick-off and quick-on is avoided), and a user can restart the computer after shutting down the computer for three seconds. After the computer is started, a main menu can be displayed, and the main menu is provided with the following icons:

database TEV & Ultra: entering a TEV & Ultra database setting interface, wherein the interface is used for storing and setting data files especially aiming at the measured characteristics of the switch cabinet; under the TEV & Ultra database, a user can build the database through a new building button and select the current database by selecting the serial number in front of the database;

setting: entering a mode for setting each system parameter and displaying equipment system information;

ultra measurement: measuring an Ultra sensor to obtain a signal;

ultra map: measuring an Ultra sensor in a spectrum mode to obtain a signal;

TEV measurement: measuring a TEV sensor to obtain a signal;

TEV spectra: the TEV sensor is measured spectroscopically to obtain a signal.

UHF measurement: measuring a UHF sensor to obtain a signal;

UHF spectrum: measuring a UHF sensor in a spectrum mode to obtain a signal;

HFCT measurement: measuring an HFCT sensor to obtain a signal;

HFCT atlas: spectrally measuring the HFCT sensor to obtain a signal;

AE measurement: measuring an AE sensor to obtain a signal;

AE atlas: measuring an AE sensor in a spectrum mode to obtain a signal;

hiding function: when a Logo area on a main interface is clicked, a Logo picture can be switched, the equipment state is also switched between 'use' and 'connection', and when the equipment state is 'connection', the equipment can be directly connected with a computer or a mobile phone to transfer detection data.

The TEV ground voltage detection is carried out by using the method: the frequency range is 3M-100MHz, the measurement range is 0dBmV-60dBmV, the resolution is as follows: 1dBmV, the operation mode is capacitive coupling. Performing Ultra ultrasonic detection: the resonance frequency is 40KHz +/-1 KHz, the measurement range is-5 dBuV-69dBuV, and the resolution is as follows: . + -. 1 dBuV. Carrying out UHF ultrahigh frequency detection: the frequency range is 300M-3000MHz, the measurement range is-75-0 dBmV, the resolution is as follows: 1 dBm. Carrying out HFCT high-frequency detection: the frequency range is 1MHz-100MHz, the measuring range is 0-200mV, and the resolution is as follows: 0.1 mV. Carrying out AE ultrasonic detection: the frequency range is 10KHz-200KHz, the measurement range is 0-100mV, and the resolution is as follows: 0.1 mV. The operating environment of the invention is as follows: operating temperature: 0-55 ℃, humidity 0-90%, international protection grade: 54.

it is important to the present invention that the instrument be kept clean and dry, that the instrument not be waterproof, that the instrument be stored in a humid environment, that the instrument be used without exceeding temperature limits, that the instrument be excessively shaken and bumped, that the instrument be excessively squeezed, and that the instrument and its accessories be disassembled. The instrument can be wiped clean by a wet cloth, and if the instrument is seriously polluted, the instrument can be cleaned by a foam detergent, and attention must be paid to the cleaning process without allowing liquid to enter the instrument. The instrument must be wiped with a soft cloth, taking care not to scratch the surface of the instrument, especially the liquid crystal display part.

The invention is used for monitoring the partial discharge condition of the power equipment on line. If the discharge signal is not detected, the method cannot be used as a basis for the fact that no partial discharge activity exists in the tested electric equipment. Partial discharge activity is often intermittently halted and other factors besides partial discharge activity may also cause damage to the device insulation structure. If a considerable discharge signal is detected on the equipment directly connected to the high and medium voltage systems, the department responsible for the electrical equipment should be immediately informed to draw sufficient attention and to handle it in a timely manner.

The personnel who adopt the invention to carry out the partial discharge live detection should have the following conditions:

receiving the training of local discharge live detection of the power equipment, being familiar with the basic principle and the diagnostic analysis method of the local discharge detection technology, knowing the working principle, technical parameters and performance of the local discharge detection instrument, mastering the operation method of the local discharge detection instrument and having the field detection capability;

the structural characteristics, the working principle and the operating condition of the tested electric equipment and basic factors causing equipment failure are known;

the system has certain field working experience, is familiar with and can strictly comply with relevant safety management regulations of power production and working fields;

the physical condition and mental condition on the day of detection are good.

Relevant site safety operating specifications and requirements, such as national grid company electric power safety work regulations (substation section), should be strictly observed.

The requirements of the power plant, substation and company on-site safety and on-site testing should be strictly enforced.

The field partial discharge live detection work is not less than two persons. The guardian should always perform the monitoring duty during the detection period and must not leave the post or do other jobs concurrently;

before testing can be performed, it must be ensured that the device under test is reliably grounded.

Forbidding detection work in the thunderstorm weather period;

during detection, detection personnel and detection instruments are required to keep a sufficient safety distance from the charged part of the equipment;

the detection personnel should avoid the equipment pressure relief channel;

when the detection is carried out, the device to be detected is prevented from being touched by mistake and being operated by mistake.

The coaxial cable used by the instrument is kept to be completely unfolded in detection, random waving is forbidden when the coaxial cable is wound and unwound, and the sheath of the coaxial cable is prevented from being scratched;

when the sensor is used for detection, if the voltage is obviously induced, the insulating gloves are worn to avoid the hands from directly contacting the metal parts of the sensor;

and if the abnormal situation occurs in the detection site, the detection work is immediately stopped and the detection site is evacuated.

To ensure personal and equipment safety, the following requirements should be noted, in addition to strict enforcement of power-related safety standards and safety regulations:

no other operation is performed on the tested power equipment;

the metal shell and the grounding lead of the tested electric equipment are reliably grounded, and the charged part is well insulated from the detecting instrument and the sensor;

the influence brought by other interference sources is avoided as much as possible in the process of being tested, and the reading of the instrument is influenced by the strong magnetic field and the unshielded circuit with the frequency within the range of 1GHz of the mobile phone, the transceiver and the video display device. The instrument is held in air at least 1 meter from any conductor surface where environmental measurements can be obtained.

The same tested device should keep the position of each testing point consistent as much as possible so as to facilitate comparative analysis.

When partial discharge of the switch cabinet is measured, a host (with built-in TEV and Ultra sensors) is used, and a UHF module and a sensor thereof can be additionally arranged; when partial discharge of GIS equipment is measured: using a host, an AE sensor, a UHF module and a sensor; when the cable is tested to be partially discharged: the host machine and HFCT module and the sensor thereof are used, and an AE sensor and a waveguide rod can be additionally arranged; when partial discharge of the transformer is measured: the UHF module and the sensor can be added by using the host computer + the HFCT module and the sensor + the AE sensor.

The AE detection steps are as follows: as shown in figure 5 of the drawings,

and checking the integrity of the instrument, connecting all parts of the detection instrument, and starting the detection instrument after the detection instrument is correctly grounded.

And after starting up, performing self-inspection on the instrument, checking whether interface display and mode switching are normal and stable, and confirming that the AE sensor and the detection channel work normally.

And setting the name of the transformer substation, the name of the equipment, the detection position and marking.

The detection instrument is adjusted to the minimum range, the sensor is suspended in the air, the spatial background noise is measured and recorded, and a signal detection threshold value is set according to the field noise level.

The detection points are selected from a breaker fracture, an isolating switch, a grounding switch, a current transformer, a voltage transformer, a lightning arrester and a conductor connecting part, the outer surface of a shell attached with the sensor is wiped clean before detection, and the interval between the detection points is smaller than the effective detection range of a detection instrument.

The special detection couplant is uniformly coated on the detection surface of the ultrasonic sensor, proper pressure is applied to cling to the outer surface of the shell so as to reduce signal attenuation as much as possible, the sensor and the tested shell are kept relatively static during detection, for high-altitude equipment, such as certain GIS bus air chambers, the sensor can be supported by a matched insulating support rod to cling to the outer surface of the shell for detection, and sufficient safety distance between the sensor and an electrified part of the equipment needs to be ensured.

And observing the detected signal on a display interface, wherein the observation time is not less than 15 seconds, if no abnormality is found in the signal and the correlation between the amplitude and the frequency of 50Hz/100Hz is low, the data are saved, and the next point detection is continued.

If the signal is abnormal, multi-point detection is carried out in the air chamber, the detection time is prolonged, a plurality of groups of data are recorded for amplitude comparison and trend analysis, phase correlation analysis is accurately carried out, and a synchronous signal can be led out from the equipment body to a detection instrument.

(9) Filling in a device detection data record table, and attaching a detection picture and defect analysis to the abnormal air chamber.

The judgment method of the field detection data comprises the following steps:

TEV lateral analysis:

the transverse analysis method is suitable for TEV test analysis, namely, the same test result of all switch cabinets with the same voltage class in the same switch room is compared, when the test result of one or a plurality of switch cabinets is larger than the test results of other switch cabinets and the field background value, the possibility that the switch cabinet has defects can be judged, and the method can be specifically carried out according to the following steps: calculating the average value of the transient voltage-to-ground voltage test values of different test parts of the switch cabinet at this time

(T_iTest values for different test parts of all switch cabinets, n is the total number of test parts), and test value offset

It is determined whether the average a is greater than 20 dB. When the average a <20dB, analysis can be made with reference to the contents of table 1.

TABLE 1 maximum offset determination criteria

When the average value A is more than or equal to 20dB, judgment and analysis are carried out according to the transient voltage-to-ground fixed value judgment basis (table 2).

It should be noted that: the field test procedure may be as follows: the average value of the test is more than or equal to 20dB, but only the test values of a plurality of switch cabinets are larger than the average value A, and the Delta m% exceeds the range specified in the table 1, the test must be carried out according to the standard.

TEV constant value discrimination

The criterion for determining the transient voltage-to-ground voltage (Table 2) is applicable to the condition that the average value A in A1 is greater than 20 dB. Wherein P is the transient voltage-to-ground test value of the switch cabinet.

TABLE 2TEV definite value discrimination basis

Ultrasonic fixed value discrimination: in the ultrasonic detection, sound judgment is firstly used, and then fixed value judgment is used. The ultrasonic fixed value is judged according to the following table 3, wherein P is the ultrasonic testing value of the switch cabinet.

TABLE 3 ultrasonic definite value discrimination basis

It should be noted that: the ultrasonic wave fixed value discrimination should be performed in combination with the sound discrimination, and if it is a disturbance (corona, mechanical vibration, environmental noise, etc.), it is not suitable to use the fixed value discrimination.

Longitudinal analysis:

the longitudinal analysis method is used for analyzing the test results at different times to obtain the trend analysis of the local discharge of the switch cabinet. The longitudinal analysis method is only used for comparison analysis when the detection period of the constant data is shortened, and the normal data is not listed in the longitudinal analysis method.

The specific analysis process should be carried out as follows:

calculating average values A1 and A2 of two tests in a switch cabinet unit, wherein A1 and A2 are according to

(Ti is the test value of different test parts of the switch cabinet, and n is the total number of the test parts); calculating the offset of the mean

When delta q percent>50%, that is, the average value becomes significantly large, and after eliminating the disturbance factor, the risk level is set.

In the longitudinal analysis process, the changes of the transient voltage-to-ground voltage detection value and the ultrasonic detection value should be analyzed from the slight fluctuation of the influence factor generated by partial discharge, and the main contents are as follows:

change of load: the electrical load is different in different time periods, when the load is increased, equipment generates a heat effect to damage equipment insulation, and the long-time cumulative effect can cause the equipment insulation to crack so as to generate partial discharge.

Environmental factors fluctuate: in different time periods, external interference is staggered, and the influence of the fluctuation of background interference on a detection value is analyzed; analyzing the change conditions of the detection values under different temperature and humidity conditions; and analyzing the change condition of the detection values under different filth conditions according to the cleaning frequency of the switch cabinet. Common interference sources and an anti-interference method in the detection process are as follows:

common sources of interference are:

the strong corona interference of outdoor overhead lines can affect the ultrasonic wave and transient voltage to ground voltage test values of an incoming line cabinet and an adjacent cabinet of a switch room.

When a large motor such as a main transformer cooler runs, a higher transient voltage-to-ground test value can be generated in the shell due to the rotation of the inner coil, and further the ultrasonic wave and the transient voltage-to-ground test value of the incoming cabinet and the adjacent cabinet of the switch room are influenced.

The storage battery cabinet and the direct current cabinet have the advantages that due to the rectifying circuit inside the storage battery cabinet and the direct current cabinet, the transient voltage-to-ground voltage test value is abnormally high, but the influence range is small, and the transient voltage-to-ground voltage test value can be ignored after being opened for 2 meters and 3 meters.

The proximity of the light source can make the ultrasonic test value unusually large. The ballast is started continuously after the roof fluorescent lamp is damaged, so that the transient voltage to ground test value is greatly improved, the influence range is large, and the roof fluorescent lamp can cover a main control room or a high-voltage switch room.

The live indicator on the back of the switch cabinet can cause the transient voltage-to-ground voltage test value to be higher. Some electronic circuit boards, control boxes and the like can generate certain interference, and influence transient voltage to earth voltage test values, but the influence range is limited to the metal surface connected with the electronic circuit boards and is not more than 0.5m, for example, a fire control box and a switch cabinet are close to a control protection screen and the like.

The transient voltage-to-ground voltage test value of the construction in the downtown area is greatly influenced by vehicles and other reasons, but when shielding measures of a house exist, internal equipment is less influenced.

Audible sounds from the human ear, etc. can cause significant interference to the ultrasonic testing.

Corona discharge can significantly increase the value of ultrasonic testing methods and its sound is substantially similar to the sound generated inside a switch cabinet.

The influence distance of the interference source of the ultrasonic testing method is generally small, and the interference source has certain directivity.

And (3) processing field interference:

(1) and turning off interference sources such as indoor exhaust fans, fluorescent lamps and the like.

(2) Different times were used for the tests.

(3) Avoid interfering signals from radios and other electronic devices.

(4) The method is realized by determining the propagation direction of the signal through the portable partial discharge locator to determine a discharge interference source far away from the tested equipment.

In order to enable an inspector to touch equipment to be inspected, which is remote in position, without the aid of external force, the invention further comprises a stretching mechanism. As shown in fig. 6 to 8, the stretching mechanism includes a support box 2, a finger pressing unit, a support block 3 and an extension rod 31, as shown in fig. 7, the support box 2 is a cuboid box, an inner cavity of the support box is a host slot 21 for placing a host, the host and the host slot are in close contact, the host slot penetrates through the left end face of the support box, a through hole 22 is arranged on the rear side face of the host slot, and the through hole is arranged to avoid an LEMO interface so as to facilitate connection of an AE sensor. And an avoiding groove 23 is formed in the right side surface of the tray and is used for avoiding the Audio interface 14, the USB interface 15, the Power interface 16 and the Ant interface 17 so as to facilitate wiring. As shown in fig. 6, an upper plate 25 is arranged above the support box, the upper plate and the support box are fixedly connected through a support rod, as shown in fig. 8, a plurality of sliding grooves 253 are arranged at the bottom of the upper plate, the sliding grooves correspond to the touch keys of the host display screen one by one, a plurality of spring grooves 251 are arranged at the top of the upper plate, the spring grooves correspond to the sliding grooves one by one and are communicated with the sliding grooves up and down, a positioning ring 252 fixedly connected with the support plate is arranged at the upper part of each spring groove, the positioning ring is a circular ring, and the circular hole at the center of the positioning. A spring 41 is arranged in a spring groove, a finger pressing block 4 is arranged in the sliding groove in a sliding mode, the finger pressing block moves up and down in the sliding groove, the upper end of the spring is fixedly connected with a positioning ring, and the lower end of the spring is fixedly connected with the finger pressing block. The spring is in a compressed state all the time in the spring groove, and the finger pressing block is made of silica gel and used for pressing the touch key. After the host computer is arranged in the tray box, the finger pressing block is not in contact with the host computer and has a gap of 3-6 mm.

A cross rod 26 is fixed on the upper portion of the right end of the upper plate, the cross rod is a round rod, a plurality of first lug plates 27 are fixed on the top of the upper plate, and the first lug plates correspond to the sliding grooves one to one. As shown in fig. 9, when the touch screen is provided with two rows arranged left and right, the first ear plates may be provided in two groups arranged left and right, and the first ear plates in each group are located on one inclined line. A first thread wheel 28 is fixedly installed on each first lug plate, a support block 3 is arranged below the support box, outward extending rods 31 are respectively arranged between the front side face of the support block and the front side face of the support box, between the rear side face of the support block and the rear side face of the support box, the outward extending rods are hinged with the support block, and are hinged with the support box, two outward extending rods are arranged on the same side of the support box and the support block, and four outward extending rods are arranged on the outward extending rods. The extension rod, the support box and the support block form a parallelogram connecting rod structure, and when the extension rod swings, the extension of the support box can be driven. To lock the outwardly extending rods, a positioning plate 33 is provided at the top of the holder, and a positioning bolt 32 is provided between the positioning plate and one of the outwardly extending rods. When the outward extending rod needs to be loosened or locked, the positioning bolt can be rotated forwards and backwards. The top of the supporting block is provided with a display 37, the bottom of the supporting plate is provided with a camera, the camera can shoot pictures on a display screen of a host on the supporting box, and the camera is connected with the display and displays the shot pictures on the display. A plurality of second lug plates 34 are fixed on the top of the support block, second wire wheels 35 are rotatably installed on the second lug plates, the second wire wheels correspond to the first wire wheels one by one, pull wires 29 are arranged between the corresponding second wire wheels and the finger-pressing blocks, and the outer walls of the pull wires and the finger-pressing blocks and the pull wires and the outer walls of the second wire wheels are fixedly connected. The stay wire is also contacted with the cross shaft so as to avoid friction and interference caused by contact between the stay wire and the supporting plate. A knob 36 is fixed on the second wire wheel, a torsion spring is arranged between the second wire wheel and the second lug plate, and the second wire wheel pulls the pull wire under the action of the torsion spring to enable the finger pressing block to be arranged in the sliding groove and a gap is formed between the finger pressing block and the host machine on the support box. When the knob is held and driven to rotate, the acting force of the torsion spring can be overcome to enable the second wire wheel to release the pull wire, and the finger pressing block is ejected out under the action of the spring until the finger pressing block is contacted with the touch key on the host machine.

Touch keys on the display screen can be displayed on the display one by one, and the second wire wheels correspond to the touch keys one by one, so that the corresponding touch keys can be pressed through the remote operation knob. Different functions can be realized through the host, and different functions comprise different types and numbers of touch keys, but only the touch keys are ensured to be in one-to-one correspondence with the finger pressing block and the second wire wheel. The number of the second wire wheels is at least equal to the number of the touch keys on the display screen when the number of the second wire wheels is the largest. The finger pressing block, the spring, the pull wire, the first wire wheel, the second wire wheel, the knob and the torsion spring form a finger pressing unit.

When the equipment to be detected (such as a switch cabinet) is in touch with hands, a detector can hold the host to directly detect; when waiting to detect equipment manpower can not touch in time, the tray can be handed to the operator to place the host computer on holding in the palm the box, then swing the outer pole of stretching out and make and hold in the palm the box and place suitable high position in, and make the host computer press close to or contact equipment of waiting to detect.

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

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.

Claims (7)

1. A multifunctional partial discharge detection system is characterized in that; comprises a multifunctional partial discharge detection device and an extension mechanism,

the multifunctional partial discharge detection device comprises a host and a detector body connected with the host, wherein the detector body comprises:

the ultrahigh frequency signal acquisition module is arranged at the disc insulator outside the GIS body and is configured to detect an ultrahigh frequency signal excited by partial discharge inside the disc insulator outside the GIS body;

the high-frequency current signal acquisition module is arranged on the cable grounding wire and is configured to detect a pulse signal emitted from a partial discharge point and carry out coupling output;

an AE sensor configured to detect an ultrasonic signal of a surface of the transformer case or body;

the host receives the ultrahigh frequency signal, the pulse signal and the ultrasonic signal, and is configured to perform fault degree evaluation, fault position analysis and fault type preliminary identification according to comparison of amplitude, phase or original signal characteristics of the received signal and a background signal and analysis of relevant characteristics of power frequency;

the stretching mechanism comprises a support box, a support block, a finger pressing unit and an outward extending rod, the support box and the support block are arranged up and down, the outward extending rod is arranged between the support box and the support block, the support plate is arranged above the support box, the finger pressing unit is arranged between the support plate and the support block and is used for pressing to control the host;

the outer extension rod and the support box as well as the outer extension rod and the support block are hinged, the outer extension rod, the support box and the support block form a parallelogram link mechanism, a positioning plate is arranged on the support block, and a positioning bolt is arranged between the positioning plate and one of the outer extension rods;

the finger pressing unit comprises a finger pressing block made of silica gel and arranged at the bottom of the supporting plate in a sliding mode, a spring arranged between the finger pressing block and the supporting plate, a first wire wheel arranged on the supporting plate, a second wire wheel arranged on the supporting plate, a knob fixed on the second wire wheel and a torsion spring arranged between the second wire wheel and the supporting plate, the finger pressing block corresponds to touch keys of the detection device one by one, pull wires are arranged between the finger pressing block and the outer wall of the second wire wheel, and the pull wires are in contact with the first wire wheel; under the action of the spring, a gap is formed between the pressing block and the supporting box, and the spring is always in a compressed state;

the top of the supporting block is provided with a display, the bottom of the supporting plate is provided with a camera, the camera shoots pictures on a display screen of the host computer on the supporting box, and the camera is connected with the display and displays the shot pictures on the display.

2. The multifunctional partial discharge detection system of claim 1, wherein: the built-in Ultra sensor of host computer and TEV sensor, be equipped with the LEMO interface with AE sensor signal connection on the host computer, be equipped with the Audio interface, the USB interface that are used for connecing the Ultra passageway to monitor the earphone bottom the host computer, with the Power interface that external Power source is connected and be used for the Ant interface with the external antenna connection of synchronous Power source wireless trigger.

3. The multifunctional partial discharge detection system of claim 1, wherein: the high-frequency current signal acquisition module is directly clamped on a cable grounding wire to detect pulse signals emitted from a partial discharge point, coupling output is carried out, and the host computer carries out real-time monitoring and analysis after receiving the output.

4. The multifunctional partial discharge detection system of claim 1, wherein: the host is provided with an input key to control the on-off action of the host.

5. The multifunctional partial discharge detection system of claim 1, wherein the bottom of the supporting plate is provided with a sliding groove, and the finger pressing block is connected with the sliding groove in a sliding manner; the top of the supporting plate is provided with a spring groove, the upper part of the spring groove is provided with a positioning ring, and the spring is arranged in the spring groove.

6. The method of operation based on the system of claim 5, wherein: according to the comparison of the amplitude, phase and original signal characteristics of the received ultrahigh frequency signal, pulse signal and ultrasonic signal with the background signal and the analysis of the relevant characteristics with the power frequency, fault degree evaluation, fault position analysis and fault type preliminary identification are carried out;

when the equipment to be detected is not contactable, the extension mechanism is utilized to extend, so that the host machine is close to or contacts the equipment to be detected.

7. The method of claim 6, wherein the signal is analyzed by TEV lateral analysis, TEV fixed value discrimination or longitudinal analysis.

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