CN215986299U - Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment - Google Patents
Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment Download PDFInfo
- Publication number
- CN215986299U CN215986299U CN202121968478.5U CN202121968478U CN215986299U CN 215986299 U CN215986299 U CN 215986299U CN 202121968478 U CN202121968478 U CN 202121968478U CN 215986299 U CN215986299 U CN 215986299U
- Authority
- CN
- China
- Prior art keywords
- disturbance
- shielding
- measurement system
- voltage detection
- detection module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The utility model belongs to the technical field of power systems, and particularly relates to a transient electromagnetic disturbance multi-stage measurement system for power intelligent equipment, which comprises: the outdoor machine box comprises an outdoor machine box, a first shielding space and a second shielding space, wherein the first shielding space and the second shielding space are positioned in the outdoor machine box; a data acquisition unit is arranged in the first shielding space; a plurality of stages of units to be tested are placed in the second shielding space; the multi-stage tested unit comprises a chip and a functional circuit which are connected with each other; the data acquisition unit comprises a processor module; the high-voltage detection modules are used for detecting disturbance voltage values of the ports of the functional circuit; and the low-voltage detection modules are used for detecting the disturbance voltage value of the chip pins.
Description
Technical Field
The utility model belongs to the technical field of power systems, and particularly relates to a transient electromagnetic disturbance multi-stage measurement system for power intelligent equipment.
Background
Along with the rapid development of the power transformation technology towards the direction of high capacity, intellectualization and integration, the electromagnetic disturbance in the transformer substation is more and more in variety, the frequency spectrum is wider and wider, the intensity is larger and larger, and the whole machine and the chip of the electric intelligent equipment are greatly impacted. The power intelligent device chip exposed in the complex electromagnetic environment puts higher requirements on the electromagnetic interference protection capability of the power intelligent device chip. Compared with the complete machine electromagnetic compatibility research, the research on the chip-level electromagnetic compatibility technology is still in the starting stage, so that the chip-level electromagnetic compatibility technology research of the power intelligent equipment is urgently needed to be developed, a technical system for testing, simulating and suppressing the electromagnetic transient interference from the complete machine to the chip level is established, and the anti-interference capability of the power intelligent equipment is integrally improved. The existing method for measuring transient electromagnetic disturbance of the electric intelligent device mainly comprises port conducted disturbance voltage measurement, less measurement on a space transient radiation electromagnetic field and less measurement on electromagnetic disturbance on an inner core plate. The main reason is that the transient electromagnetic field probe is difficult to manufacture and calibrate, and the existing electromagnetic pulse probe cannot meet the requirement of transient electromagnetic disturbance measurement of the intelligent electric power equipment; meanwhile, the chip measuring probe is difficult to fix, and the space for arranging the measuring equipment is limited.
SUMMERY OF THE UTILITY MODEL
The technical problem to be solved by the utility model is as follows: and realizing multi-stage transient electromagnetic disturbance measurement.
The technical scheme adopted by the utility model for solving the technical problems is as follows: this multistage measurement system of electric power intelligent equipment transient state electromagnetism disturbance includes: the outdoor machine box comprises an outdoor machine box, a first shielding space and a second shielding space, wherein the first shielding space and the second shielding space are positioned in the outdoor machine box; a data acquisition unit is arranged in the first shielding space; a plurality of stages of units to be tested are placed in the second shielding space; the multi-stage tested unit comprises a chip and a functional circuit which are connected with each other; the data acquisition unit comprises a processor module; the high-voltage detection modules are used for detecting disturbance voltage values of the ports of the functional circuit; and the low-voltage detection modules are used for detecting the disturbance voltage value of the chip pins.
Further, the high voltage detection module includes: the device comprises an installation bottom plate, a plurality of fixed clamping blocks positioned on the installation bottom plate and a high-voltage differential probe positioned on the fixed clamping blocks; the high voltage differential probes are connected in parallel and connected to a plurality of ports of the functional circuit through respective first BNC connectors.
Further, the low voltage detection module includes: the device comprises a shielding box, a plurality of BNC connectors positioned on the shielding box, a plurality of insulating clamping blocks positioned in the shielding box and a passive probe installed on the insulating clamping blocks; the passive probes are connected in parallel and led out of the shielding box through corresponding second BNC connectors so as to be connected to a plurality of pins of the chip.
Furthermore, the multi-stage tested unit also comprises an interference suppression circuit positioned between the chip and the functional circuit; the low-voltage detection module is also used for detecting the disturbance voltage value of the port of the disturbance suppression circuit.
Further, the electric intelligent device transient electromagnetic disturbance multistage measurement system further comprises a magnetic field detection module for detecting a transient electric field; the magnetic field detection module comprises a first magnetic field probe positioned in the second shielding space and used for detecting the magnetic field intensity in the second shielding space; and the second magnetic field probe is positioned outside the outdoor case and used for detecting the magnetic field intensity outside the outdoor case.
Further, the first shielding space is adapted to be formed by an inside of the shielding case; the interior of the shielding box body is divided into a plurality of layers of chambers along the vertical direction through a supporting plate so as to respectively place the low-voltage detection module, the processor module and the high-voltage detection module.
Further, the pallet may be detachably mounted to adjust the number of chambers.
Further, the shielding box body comprises at least five chambers, namely a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber which are sequentially arranged from top to bottom; at least two low-voltage detection modules and at least two high-voltage detection modules are arranged; the low-voltage detection module, the power filter and the communication interface are arranged in the first cavity; the low-pressure detection module is placed in the second chamber; the processor module, the PDU socket and the communication module are arranged in the third chamber; the high-pressure detection module is respectively arranged in the fourth cavity and the fifth cavity.
Further, the outdoor case is made of a shielding material, so that the second shielding space is formed in a space between the shielding case and the outdoor case.
The utility model has the beneficial effects that: the transient electromagnetic disturbance multistage measurement system of the power intelligent equipment respectively places the data acquisition unit and the multistage unit to be measured through the first shielding space and the second shielding space, is convenient for equipment installation and use through the integrated arrangement, and can also reduce electromagnetic disturbance in the data acquisition process; the disturbance voltage value measurement of the functional circuit port and the disturbance voltage value measurement of the chip pin are combined together, as long as any one of the two measured values exceeds a corresponding threshold value set by the processor module, the processor module controls the two to work simultaneously, transient electromagnetic disturbance of the functional circuit level and the chip level can be measured, a multi-level cooperative measurement mode is formed, disturbance synchronous measurement of the same disturbance source on different coupling paths and different sensors is achieved, and accuracy of measured data is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts. The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, and merely illustrates the basic structure of the present invention in a schematic manner, and therefore it shows only the constitution related to the present invention.
FIG. 1 is a schematic block diagram of a transient electromagnetic disturbance multi-stage measurement system of an electric power intelligent device of the present invention;
FIG. 2 is a schematic structural diagram of an outdoor enclosure of the present invention;
FIG. 3 is a schematic diagram of the high voltage detection module of the present invention;
FIG. 4 is a schematic diagram of the low voltage detection module of the present invention;
in the figure:
an outdoor cabinet 1;
the first shielding space 2, the shielding box body 21, the supporting plate 22, the chamber 23, the first chamber 231, the second chamber 232, the third chamber 233, the fourth chamber 234, the fifth chamber 235, the sixth chamber 236 and the cabinet door 24;
the second shielded space 3;
the system comprises a data acquisition unit 4, a processor module 41, a high-voltage detection module 42, a mounting base plate 421, a fixed clamp 422, a high-voltage differential probe 423, a first BNC connector 424, a low-voltage detection module 43, a shielding box 431, a second BNC connector 432, an insulating clamp 433, a passive probe 434, a power filter 44, a communication interface 45, a PDU socket 46 and a communication module 47;
the multi-stage tested unit 5, the chip 51, the chip pin 511, the functional circuit 52, the functional circuit port 521, the interference suppression circuit 53 and the interference suppression circuit port 531;
the magnetic field detection module 6, a first magnetic field probe 61 and a second magnetic field probe 62.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 to 4, the multistage measurement system for transient electromagnetic disturbance of electric power intelligent equipment in the embodiment includes: the outdoor cabinet comprises an outdoor cabinet 1, a first shielding space 2 and a second shielding space 3, wherein the first shielding space and the second shielding space are positioned in the outdoor cabinet 1; a data acquisition unit 4 is arranged in the first shielding space 2; a plurality of stages of units to be tested 5 are placed in the second shielding space 3; the multi-stage unit under test 5 comprises a chip 51 and a functional circuit 52 which are connected with each other; the data acquisition unit 4 comprises a processor module 41; the high-voltage detection modules 42 are used for detecting disturbance voltage values of the ports 521 of the functional circuit 52; and the low-voltage detection modules 43 are used for detecting the disturbance voltage value of the pin 511 of the chip 51. Generally, the voltage value of the port 521 of the functional circuit 52 is greater than the voltage value of the pin 511 of the chip 51, so that the high-voltage detection module 42 and the low-voltage detection module 43 can work simultaneously, transient electromagnetic disturbance at the functional circuit level and the chip level is measured, a two-level cooperative measurement mode is formed, synchronous measurement of disturbance of the same disturbance source and different coupling paths and different receptors is realized, and a foundation is laid for multi-level electromagnetic disturbance research.
As an alternative embodiment of the outdoor cabinet 1. Referring to fig. 1 and 2, the outdoor chassis 1 is made into a box-shaped structure by shielding materials; the first shielded space 2 is adapted to be formed by the inside of the shield case 21; the space between the shield case 21 and the outdoor cabinet 1 forms the second shield space 3. The interior of the shielding box 21 is vertically divided into a plurality of chambers 23 by the supporting plate 22, so as to respectively place the low voltage detection module 43, the processor module 41 and the high voltage detection module 42. In particular, the number of chambers 23 can be adjusted by removably mounting the support plate 22. For example, when there are at least two low voltage detection modules 43 and high voltage detection modules 42, the shielding box should include at least five chambers 23, i.e., a first chamber 231, a second chamber 232, a third chamber 233, a fourth chamber 234, and a fifth chamber 235 arranged from top to bottom; wherein the low voltage detection module 43, the power filter 44 and the communication interface 45 are disposed in the first chamber 231; the low pressure detection module 43 is disposed in the second chamber 232; the processor module 41, the PDU socket 46 and the communication module 47 are arranged in the third chamber 233; the high pressure detection module 42 is disposed in the fourth chamber 234 and the fifth chamber 235. In fig. 2, a sixth chamber 236 is also provided below the fifth chamber 235 as a reserve chamber.
Optionally, the communication module 47 is, for example, but not limited to, a 4G module. The shielding box body 21 is further provided with a cabinet door 24 suitable for opening and closing, so that the data acquisition unit 5 in the shielding box body 21 can be conveniently detached.
Optionally, the multi-stage unit under test 5 is located in the second shielding space 3, and a single-layer shielding effect can be formed by the outdoor enclosure 1.
This embodiment's outdoor machine case 1 forms first shielding space 2 through shielding box 21, has double-deck shielding effect, can reduce external magnetic field to data acquisition unit 5's interference, cut apart into multilayer structure through layer board 22 with shielding box 21 simultaneously, with each partial structure of placing data acquisition unit 4 respectively, both can avoid the mutual interference between the test module, do benefit to data acquisition unit 4 again and multistage 5 integrated forms of unit under test installation, the wire of being convenient for is arranged, spatial layout is reasonable.
As an alternative embodiment of the high voltage detection module 42. Referring to fig. 3, the high voltage detection module 42 includes: the differential probe comprises a mounting bottom plate 421, a plurality of fixed clamping blocks 422 positioned on the mounting bottom plate 421 and a high-voltage differential probe 423 positioned on the fixed clamping blocks 422; the high-voltage differential probes 423 are connected in parallel and connected to the ports 521 of the functional circuit 52 through the corresponding first BNC connectors 424, so as to detect the transient electromagnetic disturbance voltage value of the functional circuit level and completely record the state of the whole disturbance waveform. The high-voltage differential probe 423 is arranged in parallel, the working voltage in the high-voltage differential probe 423 and the voltage of the circuit common ground are arranged close to each other in pairs under the condition that power supply is not influenced, and by adopting a parallel arrangement method, the currents flowing in opposite directions generate magnetic fields which are mutually counteracted, so that electromagnetic radiation is reduced.
As an alternative embodiment of the low voltage detection module 41. Referring to fig. 4, the low voltage detection module 43 includes: a shield can 431, a number of second BNC connectors 432 located on the shield can 431, a number of insulating blocks 433 located within the shield can 431, and a passive probe 434 mounted on the insulating blocks 433; the passive probes 434 are connected in parallel and led out of the shielding box 431 through corresponding second BNC connectors 432 to be connected to a plurality of pins 511 of the chip 51, so as to detect the transient electromagnetic disturbance voltage value of the chip level and completely record the state of the whole disturbance waveform. Because the physical size of the pins of the main control chip special for electric power is small, the traditional probe cannot be electrically connected with the pins, the disturbance waveforms of the pins of the chip cannot be measured, and even the disturbance waveforms are calculated by using the disturbance waveforms of the device port in an electromagnetic simulation mode, the method for obtaining the disturbance of the pins of the main control chip special for electric power is high in complexity and high in technical difficulty. In the scheme, the passive probes 434 (namely, the traditional probes) are arranged inside the shielding box 431 side by side and then led out to the outside of the shielding box 431 through the second BNC connector 432 to be connected to the pins 511 of the chip 51, so that the problem of connection between the traditional probes and the pins of the chip is solved, a three-layer shielding effect is formed through the shielding box 431, the shielding box body 21 and the outdoor case 1, the electromagnetic disturbance of the low-voltage detection module 43 can be obviously reduced, and the measurement accuracy is improved. In addition, the passive probes 434 are arranged in parallel, so that the working voltage inside the passive probes 434 and the voltage of the common ground of the circuit are arranged close to each other in pairs under the condition of not influencing the power supply, and by adopting the parallel arrangement method, the currents flowing in opposite directions generate magnetic fields which are mutually counteracted, thereby reducing the electromagnetic radiation.
Optionally, the insulating clamping block 433 and the fixing clamping block 422 may both be made of polyurethane, so as to perform an insulating function.
Optionally, the state of the disturbance waveform includes, but is not limited to, a peak-to-peak value of a macro pulse, a maximum peak value of a macro pulse, a duration of a macro pulse, a number of micro pulses, a micro pulse interval time, a duration of a micro pulse, a rise time of a micro pulse, and a dominant frequency distribution of a micro pulse.
Further, referring to fig. 1, the multi-stage unit under test further includes an interference suppression circuit 53 located between the chip 51 and the functional circuit 52; the low-voltage detection module is also used for detecting a disturbance voltage value of the port 531 of the disturbance suppression circuit 53; when any one of the disturbance voltage value of the port 521 of the functional circuit 52, the disturbance voltage value of the pin 511 of the chip 51 and the disturbance voltage value of the port 531 of the disturbance suppression circuit 53 exceeds the corresponding threshold value set by the processor module 41, the processor module 41 simultaneously starts the high-voltage detection module 42 and the low-voltage detection module 43, and simultaneously measures transient electromagnetic disturbance of the functional circuit level, the disturbance suppression circuit level and the chip level to form a three-level cooperative measurement mode.
As an alternative embodiment of the magnetic field detection module 6. Referring to fig. 1 and fig. 2, the electric intelligent device transient electromagnetic disturbance multistage measurement system further includes a magnetic field detection module 6 for detecting a transient electric field; the magnetic field detection module 6 comprises a first magnetic field probe 61 positioned inside the second shielded space 3 and used for detecting the magnetic field intensity inside the second shielded space 3; and the second magnetic field probe 62 is positioned outside the outdoor case 1 and used for detecting the magnetic field strength outside the outdoor case 1, and the first magnetic field probe 61 is combined with the second magnetic field probe 62 to realize the transient electric field measurement of the space magnetic field. When the magnetic field intensity outside the outdoor case 1 or the magnetic field intensity inside the second shielding space 3 is greater than the corresponding threshold value set by the processor module, the processor module adjusts the parameters of the power filter 44 to reduce the interference of the magnetic field on the chip-level transient electromagnetic disturbance measurement result.
Optionally, a protective cover is further disposed outside the second magnetic field probe 62.
In the scheme, the measurement of the conduction disturbance voltage of the port of the functional circuit, the measurement of the disturbance voltage of the port of the disturbance suppression circuit, the measurement of the disturbance voltage of the pin of the chip and the measurement of the transient electric field are combined together to obtain the transient electromagnetic disturbance multistage measurement system of the power intelligent device, the transient electromagnetic disturbance of the functional circuit and the transient electromagnetic disturbance of the chip can be measured in a coordinated mode, and the synchronous measurement of the disturbance of different receptors on different coupling paths of the same disturbance source is realized.
In light of the foregoing description of preferred embodiments in accordance with the utility model, it is to be understood that numerous changes and modifications may be made by those skilled in the art without departing from the scope of the utility model. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (9)
1. The utility model provides a multistage measurement system of electric power smart machine transient state electromagnetism disturbance which characterized in that includes: the outdoor machine box comprises an outdoor machine box, a first shielding space and a second shielding space, wherein the first shielding space and the second shielding space are positioned in the outdoor machine box; a data acquisition unit is arranged in the first shielding space; a plurality of stages of units to be tested are placed in the second shielding space; the multi-stage tested unit comprises a chip and a functional circuit which are connected with each other; the data acquisition unit comprises a processor module; the high-voltage detection modules are used for detecting disturbance voltage values of the ports of the functional circuit; and the low-voltage detection modules are used for detecting the disturbance voltage value of the chip pins.
2. The electric power intelligent device transient electromagnetic disturbance multi-stage measurement system according to claim 1, wherein the high voltage detection module comprises: the device comprises an installation bottom plate, a plurality of fixed clamping blocks positioned on the installation bottom plate and a high-voltage differential probe positioned on the fixed clamping blocks; the high voltage differential probes are connected in parallel and connected to a plurality of ports of the functional circuit through respective first BNC connectors.
3. The electric power intelligent device transient electromagnetic disturbance multi-stage measurement system according to claim 1, wherein the low voltage detection module comprises: the device comprises a shielding box, a plurality of second BNC connectors positioned on the shielding box, a plurality of insulating clamping blocks positioned in the shielding box and a passive probe installed on the insulating clamping blocks; the passive probes are connected in parallel and led out of the shielding box through corresponding BNC connectors so as to be connected to a plurality of pins of the chip.
4. The electric intelligent device transient electromagnetic disturbance multi-stage measurement system according to claim 1 or 3, wherein the multi-stage unit under test further comprises an interference suppression circuit between the chip and the functional circuit; the low-voltage detection module is also used for detecting the disturbance voltage value of the port of the disturbance suppression circuit.
5. The multistage measurement system for transient electromagnetic disturbance of electric power intelligent equipment according to claim 1, characterized in that the multistage measurement system for transient electromagnetic disturbance of electric power intelligent equipment further comprises a magnetic field detection module for detecting a transient electric field; the magnetic field detection module comprises a first magnetic field probe positioned in the second shielding space and used for detecting the magnetic field intensity in the second shielding space; and the second magnetic field probe is positioned outside the outdoor case and used for detecting the magnetic field intensity outside the outdoor case.
6. The electric power intelligent device transient electromagnetic disturbance multi-level measurement system of claim 1, wherein the first shielded space is adapted to be formed through an interior of a shielded box; the interior of the shielding box body is divided into a plurality of layers of chambers along the vertical direction through a supporting plate so as to respectively place the low-voltage detection module, the processor module and the high-voltage detection module.
7. The power intelligent device transient electromagnetic disturbance multi-level measurement system of claim 6, wherein the pallet is removably mounted to adjust the number of chambers.
8. The electric power intelligent device transient electromagnetic disturbance multistage measurement system according to claim 6, wherein the shielding box body comprises at least five chambers, namely a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber which are sequentially arranged from top to bottom; at least two low-voltage detection modules and at least two high-voltage detection modules are arranged; the low-voltage detection module, the power filter and the communication interface are arranged in the first cavity; the low-pressure detection module is placed in the second chamber; the processor module, the PDU socket and the communication module are arranged in the third chamber; the high-pressure detection module is respectively arranged in the fourth cavity and the fifth cavity.
9. The multistage measurement system of transient electromagnetic disturbance of electric power intelligent devices of claim 6, wherein the outdoor cabinet is made of a shielding material, so that the space between the shielding box and the outdoor cabinet forms the second shielding space.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121968478.5U CN215986299U (en) | 2021-08-20 | 2021-08-20 | Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121968478.5U CN215986299U (en) | 2021-08-20 | 2021-08-20 | Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215986299U true CN215986299U (en) | 2022-03-08 |
Family
ID=80519667
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121968478.5U Active CN215986299U (en) | 2021-08-20 | 2021-08-20 | Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215986299U (en) |
-
2021
- 2021-08-20 CN CN202121968478.5U patent/CN215986299U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103487780B (en) | A kind of GIS electronic transformer test macro and method thereof | |
| CN113533893A (en) | Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment | |
| CN103700244B (en) | Power line carrier meter reading networking test system | |
| CN203502582U (en) | GIS electronic transformer test system based on disconnecting switch switching-on and switching-off capacitive small current | |
| Wu et al. | Evaluation of electromagnetic radiation from the DC side of a photovoltaic power generation system | |
| CN111600633A (en) | Low pressure collection is copied testing arrangement based on HPLC | |
| CN215986299U (en) | Multistage measurement system for transient electromagnetic disturbance of electric intelligent equipment | |
| CN204666743U (en) | A kind of test cabinet with electromagnetic compatibility test probe | |
| CN106405301A (en) | Parameter acquisition cabinet | |
| CN109470961A (en) | A kind of omnipotent detection station of power equipment quality based on modularized design | |
| CN111077395B (en) | Electromagnetic interference protection design method for acquisition board card of electronic transformer of transformer substation | |
| CN206248799U (en) | A kind of battery test system | |
| CN207703967U (en) | A kind of electromagnetic interference trouble-shooter | |
| CN211744462U (en) | Low pressure collection is copied testing arrangement based on HPLC | |
| CN107884684A (en) | A kind of electromagnetic interference trouble-shooter and application method | |
| CN212693959U (en) | PCB analysis test cabinet | |
| CN203396941U (en) | Feedback interference filtering network used in electric energy meter electrical fast transient detection | |
| CN106483451B (en) | Million kilowatt nuclear power station radioactivity monitoring system processing unit test platform | |
| Zhang et al. | Electromagnetic interference analysis in HV substation due to a static var compensator device | |
| CN209417170U (en) | A kind of omnipotent detection station of power equipment quality based on modularized design | |
| CN104459404B (en) | Charger performance parameter testing system and tool | |
| CN103346747B (en) | Feedback interference filter network in detecting for electrical energy meter electricity Clusters | |
| CN201637798U (en) | Large-sized anti-interference relaying protection test board | |
| CN215340115U (en) | Radio frequency network unit applied to multi-network node simulation system test | |
| CN211528519U (en) | Digital multimeter with anti-electromagnetic interference performance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |