CN105717366A - Online grounding resistance monitoring alarm and remote monitoring system - Google Patents

Online grounding resistance monitoring alarm and remote monitoring system Download PDF

Info

Publication number
CN105717366A
CN105717366A CN201610067052.XA CN201610067052A CN105717366A CN 105717366 A CN105717366 A CN 105717366A CN 201610067052 A CN201610067052 A CN 201610067052A CN 105717366 A CN105717366 A CN 105717366A
Authority
CN
China
Prior art keywords
module
earth resistance
processing module
concentrator
chip processing
Prior art date
Application number
CN201610067052.XA
Other languages
Chinese (zh)
Inventor
赵峰
平帅
Original Assignee
南京尚志电子科技有限公司
西安杰邦科技股份有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 南京尚志电子科技有限公司, 西安杰邦科技股份有限公司 filed Critical 南京尚志电子科技有限公司
Priority to CN201610067052.XA priority Critical patent/CN105717366A/en
Publication of CN105717366A publication Critical patent/CN105717366A/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/20Measuring earth resistance; Measuring contact resistance, e.g. of earth connections, e.g. plates
    • GPHYSICS
    • G08SIGNALLING
    • G08CTRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C17/00Arrangements for transmitting signals characterised by the use of a wireless electrical link
    • G08C17/02Arrangements for transmitting signals characterised by the use of a wireless electrical link using a radio link

Abstract

The invention relates to an online grounding resistance monitoring alarm. In the alarm, an excitation coil is connected with a first fully differential operation amplifier module, the first fully differential operation amplifier module is connected with a single-chip microcomputer processing module, an inductor coil is connected with a second fully differential operation amplifier module, the second fully differential operation amplifier module is connected with the single-chip microcomputer processing module, a display module, a program leading-in module and a data leading-out module is connected with the single-chip microcomputer processing module, and a power supply module supplies power. It is not required to arrange three auxiliary detection piles, labor and material cost during construction are avoided, the using cost is greatly reduced, original equipment needs onsite manual measurement, the alarm can be either a single neuron which realizes a single function or a combination of network technology and communication technology to store a measurement result, convenience is provided for data collection and maintenance later, and integral control for equipment is improved.

Description

Earth resistance online monitoring alarm instrument and long distance control system

Technical field

The present invention relates to earth resistance monitoring technical field, particularly relate to earth resistance online monitoring alarm instrument and based on the long distance control system on this device.

Background technology

Developing rapidly due to computer technology in recent years, earth resistance tester has also permeated substantial amounts of microprocessor technology, and it measures function, and content and precision are that general instrument institute is incomparable.Earth resistance tester is the Common Instrument of inspection, measurement of Grounding Resistance, also it is electrical safety inspection and the indispensable instrument of earth work final acceptance of construction, is widely used in the electrical equipment grounding measurement in the fields such as electric power, railway, traffic, army, telecommunications, finance, chemical industry, meteorology and the earthmeter of transmission line etc..

The development initial people of mileage of earth resistance tester use voltammetry, and this test is very original.The size of electric current must be first estimated when measuring resistance, selecting the insulated conductor in suitable cross section, when pilot study, available variable resistance R adjusts electric current, when formally measuring, then by variable resistance short circuit, the numerical value of ammeter and voltammeter gained can calculate earth resistance.Voltammetry measures ground resistance clearly disadvantageous part, and first: loaded down with trivial details, workload is big.During test, extremely 20~50 meters of earth rod distance ground, and auxiliary earth distance earth point 40~100 meters.Additionally affected greatly by external interference, sometimes cannot measure in strong voltage region.

Five the sixties Soviet Union E type megger measurement instead of voltammetry measure.Due to easy to carry, being again hand generator, workload is less than voltammetry.

The domestic earth resistance tester of the seventies comes out, and no matter in the scope of measurement, scale division value, accuracy or structure, volume, weight, will be better than " E " type megger.Therefore, in the quite a while ground meter all with hand table for typical instrument.Equipment self grounding body in use, should be disconnected by hand-rail type table with equipment, with the accuracy avoiding grounding body impact to measure.

Above-mentioned instrument is due to the relation of hand generator, coming into operation of all very poor the eighties digital grounding resistance tester of precision brings life to earth resistance, although the mode of connection of test does not have difference with hand table, but its stability is much higher more than megger pointer-type.Occur in that again a kind of digital earth resistance tester on this basis, two collimation method on-line measurements are adopted during test, auxiliary earth stake need not be played, the zero line of water pipe, caliduct or AC outlet as auxiliary earth, the indexs such as energy measurement of Grounding Resistance, soil resistivity, alternating voltage, and have automatic compensation function, not only increase certainty of measurement, also there is the function such as anti-misoperation, intelligent prompt.

Summary of the invention

The technical problem to be solved in the present invention is: provide earth resistance online monitoring alarm instrument, detect without squeezing into auxiliary detection stake (3), thus spent manpower when avoiding construction, material resources, financial resources, greatly reduce use cost, equipment originally needs manually to go on-the-spot measurement, this equipment both can be single neuron now, realize simple function, can also be combined realization networking by network technology and communication technology, measurement result can also be preserved, facilitate data acquisition and the maintenance in later stage, improve the overall control to equipment.

To achieve these goals, concrete technical scheme provided by the invention is: earth resistance online monitoring alarm instrument, it is characterised in that including:

Excitation coil, is used for producing alternating magnetic field so that producing electric current in earth lead;

First Differential OPAMP module, for amplification also output high-power driving source to drive excitation coil;

Induction coil, for the electric current in inductive grounding line and produce faradic current;

Second Differential OPAMP module, for being converted into induced voltage signal processing and amplifying by sensor current signal;

Single chip processing module, for producing a lower powered driving source and being transferred to the first Differential OPAMP module, additionally, receive the induced voltage signal of the second Differential OPAMP module transfer, carry out modulus process, read inductive voltage value the linear relationship according to induced voltage Yu earth resistance, by inductive voltage value computing the actual grounding resistance inferring correspondence;

Display module, is used for showing actual grounding resistance;

Program imports module, runs program and the linear relationship of the induced voltage being implanted in this operation program and earth resistance for importing single chip processing module;

Data derive module, are used for deriving actual grounding resistance;

Power module, is used for providing different voltage;

Described excitation coil and the first Differential OPAMP module connect, described first Differential OPAMP module is connected with single chip processing module, described induction coil and the second Differential OPAMP module connect, described second Differential OPAMP module is connected with single chip processing module, described display module, program import module and data derive module and are all connected with single chip processing module, and described power module is powered.

Further, also including alarm modules, described alarm modules is made up of broadcasting unit and driver element thereof, and described single chip processing module is connected with the driver element in alarm modules.Alarm modules is for reading the grounding resistance of reality, when breaking down, it is also possible to for alarm.

Further, also bag key-press module, described key-press module is connected with single chip processing module.Key-press module is used for selecting mode of operation and setup parameter and marginal value, also has power on/off function.

Further, described single chip processing module adopts the single-chip microcomputer of MSP430fl49 model.This function of the MCU is powerful, and low in energy consumption, energy-conserving and environment-protective.

Further, described data derive module and adopt MAX485 interface chip and RS485 interface.This chip and interface are conducive to more distance data transmission.

Wired remote monitoring system, including above-mentioned earth resistance online monitoring alarm instrument, concentrator and monitoring host computer, the data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, and described concentrator is connected with monitoring host computer by netting twine.It is suitable for 1500 meters apart from interior monitoring, monitoring host computer can show tested grounding resistance constantly, the automatic monitoring record time can be set, the interval record time is 1 ~ 200 hour, record data store form automatically, facilitate the situation of change of historical query, research and application point grounding resistance, it is possible to directly display measured value by LCD, warning marginal value can also be set by detector, there is acousto-optic report.

Further, described earth resistance metering device and concentrator adopt modbus-rtu communication modes communication.There is the features such as long-range speed is fast.

Wireless remote control system, including above-mentioned earth resistance online monitoring alarm instrument, concentrator, wireless transmitter, wireless receiver and monitoring host computer, data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, described concentrator is connected by netting twine wireless transmitter, and described wireless receiver is connected with monitoring host computer by netting twine.Radio Network System is not by distance limit, monitoring host computer can show tested grounding resistance constantly, the automatic monitoring record time can be set, the interval record time is 1 ~ 200 hour, record data store form automatically, facilitate the situation of change of historical query, research and application point grounding resistance, it is possible to directly display measured value by LCD, warning marginal value can also be set by detector, there is sound and light alarm.

Further, described wireless transmitter and wireless receiver adopt GSM/GPRS communication modes communication.GSM/GPRS communication modes has the features such as long-range speed is fast.

Compared with prior art, the invention has the beneficial effects as follows: the traditional approach without squeezing into auxiliary detection stake (3) detects, thus spent manpower when avoiding construction, material resources, financial resources, greatly reduce use cost, equipment originally needs manually to go on-the-spot measurement, this equipment both can be single neuron now, realize simple function, it is also possible to combine realization networking by network technology and communication technology, it is also possible to measurement result is preserved, facilitate data acquisition and the maintenance in later stage, improve the overall control to equipment.

Accompanying drawing explanation

The construction module schematic diagram of the earth resistance metering device in Fig. 1 present invention;

The construction module schematic diagram of the wired remote monitoring system in Fig. 2 present invention;

The construction module schematic diagram of the wireless remote control system in Fig. 3 present invention.

Detailed description of the invention

In conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail;

Embodiment 1 as it is shown in figure 1, earth resistance online monitoring alarm instrument, including:

Excitation coil, is used for producing alternating magnetic field so that producing electric current in earth lead;

First Differential OPAMP module, for amplification also output high-power driving source to drive excitation coil;

Induction coil, for the electric current in inductive grounding line and produce faradic current;

Second Differential OPAMP module, for being converted into induced voltage signal processing and amplifying by sensor current signal;

Single chip processing module, for producing a lower powered driving source and being transferred to the first Differential OPAMP module, additionally, receive the induced voltage signal of the second Differential OPAMP module transfer, carry out modulus process, read inductive voltage value the linear relationship according to induced voltage Yu earth resistance, by inductive voltage value computing the actual grounding resistance inferring correspondence;

Display module, is used for showing actual grounding resistance;

Program imports module, runs program and the linear relationship of the induced voltage being implanted in this operation program and earth resistance for importing single chip processing module;

Data derive module, are used for deriving actual grounding resistance;

Power module, is used for providing different voltage;

Described excitation coil and the first Differential OPAMP module connect, described first Differential OPAMP module is connected with single chip processing module, described induction coil and the second Differential OPAMP module connect, described second Differential OPAMP module is connected with single chip processing module, described display module, program import module and data derive module and are all connected with single chip processing module, and described power module is powered.

In order to realize broadcasting function and alarm function, earth resistance online monitoring alarm instrument also includes alarm modules, and described alarm modules is made up of broadcasting unit and driver element thereof, and described single chip processing module is connected with the driver element in alarm modules.

For marginal value and the parameter of switching working mode or input necessity, earth resistance online monitoring alarm instrument also bag key-press module, described key-press module is connected with single chip processing module.

On the basis of technique scheme, described single chip processing module adopts the single-chip microcomputer of MSP430fl49 model, and MSP430fl49 model single-chip microcomputer is the microcontroller of one group of super low-power consumption, and power supply voltage range is l.8 ~ 3.6V.Consider that the design has low-power consumption, small size, requirement that function is many, so selecting MSP430fl49, it have ROM, 2K of 60K RAM, have 8 channel sample rates to be the l2 position A/D converter of 200K, hardware multiplier, 2 with catching/the l6 bit timing device of comparand register, house dog etc. in a large number, in the design, MSP430fl49 is the core of whole instrument, mainly completes the multi pass acquisition of signal, software filtering, data operation, liquid crystal display, button and various control functions etc..MSP430fl49 is possible not only to realize independent collection, and is modified software and can also form distributed wireless acquisition system. and this Acquisition Instrument can apply in the detection of humiture and toxic and harmful.

Described data derive module and adopt MAX485 interface chip and RS485 interface.RS485 has the special feature that the electrical characteristic of (1) RS-485: adopt differential signal negative logic, and logic " 1 " represents with the voltage difference of line-to-line for+(2 ~ 6) V;Logic " 0 " represents with the voltage difference of line-to-line for-(2 ~ 6) V.Interface signal level reduces than RS-232-C, is just hardly damaged the chip of interface circuit, and this level is compatible with Transistor-Transistor Logic level, can conveniently be connected with TTL circuit.(2) the data maximum transmission rate of RS-485 is 10Mbps.(3) RS-485 interface is the combination adopting balance driver and differential receiver, and anti-common mode disturbances ability strengthens, and namely noise immunity is good.(4) communication distance maximum for RS-485 is about 1219m, and peak transfer rate is 10Mbps, and transfer rate and transmission range are inversely proportional to, under the transfer rate of 100KbpS, just can reach maximum communication distance, if longer distance need to be transmitted, it is necessary to add 485 repeaters.General 32 nodes of maximum support of RS-485 bus, if using 485 special chips, it is possible to reaching 128 or 256 nodes, maximum can support 400 nodes.The half-duplex network of RS485 interface composition, is usually two-wire system (had four-wire system connection in the past, and can only realize point-to-point communication mode, existing seldom employing), adopts Shielded Twisted Pair transmission more.This mode of connection is that bus type topological structure can mount at most 32 nodes on same bus.Being generally adopted by master-slave communication mode in RS485 communication network, namely a host tape is multiple from machine.Common twisted-pair feeder can be adopted in low speed, short distance, glitch-free occasion, otherwise, when high speed, Long line transmission, then must adopt the RS485 private cable (STP-120 Ω (forRS485&CAN) onepair18AWG) of impedance matching (being generally 120 Ω), and also should adopt armored type paired shield cable (ASTP-120 Ω (forRS485&CAN) onepair18AWG) under interference rugged environment.When using RS485 interface, for specific transmission line, the baud rate that the maximum cable length that its data signal transmission allows from RS485 interface to load transmits with signal is inversely proportional to, and this length data is mainly affected by distorted signals and noise etc..In theory, traffic rate 100Kbps and following time, the most longer transmission distance of RS485 is up to 1200 meters, but the distance transmitted in actual applications also institute's difference because of the transmission characteristic of chip and cable.Transmitting procedure can adopt the method increasing relaying signal is amplified, eight relayings can be added at most, say, that the maximum transmission distance of RS485 can reach 10.8 kilometers in theory.

Embodiment 2 is as shown in Figure 2, wired remote monitoring system, including the earth resistance online monitoring alarm instrument in embodiment 1, concentrator and monitoring host computer, data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, described concentrator is connected with monitoring host computer by netting twine, and described earth resistance metering device and concentrator adopt modbus-rtu communication modes communication.Preferably, it is possible to including multiple earth resistance metering device, described monitoring host computer is provided with monitoring software, it is possible to monitor in real time also preserves data.

Embodiment 3 is as shown in Figure 3, wireless remote control system, including the earth resistance online monitoring alarm instrument in embodiment 1, concentrator, wireless transmitter, wireless receiver and monitoring host computer, data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, described concentrator is connected by netting twine wireless transmitter, described wireless receiver is connected with monitoring host computer by netting twine, described wireless transmitter and wireless receiver adopt GSM/GPRS communication modes communication, multiple earth resistance metering device can be included, described monitoring host computer is provided with monitoring software, can monitor in real time preserve data.

The heretofore described case that is embodied as is only the preferably case study on implementation of the present invention, is not used for limiting the practical range of the present invention, and namely all equivalences made according to the content of the present patent application the scope of the claims change and modify, all should as the technology category of the present invention.

Claims (9)

1. earth resistance online monitoring alarm instrument, it is characterised in that including:
Excitation coil, is used for producing alternating magnetic field so that producing electric current in earth lead;
First Differential OPAMP module, for amplification also output high-power driving source to drive excitation coil;
Induction coil, for the electric current in inductive grounding line and produce faradic current;
Second Differential OPAMP module, for being converted into induced voltage signal processing and amplifying by sensor current signal;
Single chip processing module, for producing a lower powered driving source and being transferred to the first Differential OPAMP module, additionally, receive the induced voltage signal of the second Differential OPAMP module transfer, carry out modulus process, read inductive voltage value the linear relationship according to induced voltage Yu earth resistance, by inductive voltage value computing the actual grounding resistance inferring correspondence;
Display module, is used for showing actual grounding resistance;
Program imports module, runs program and the linear relationship of the induced voltage being implanted in this operation program and earth resistance for importing single chip processing module;
Data derive module, are used for deriving actual grounding resistance;
Power module, is used for providing different voltage;
Described excitation coil and the first Differential OPAMP module connect, described first Differential OPAMP module is connected with single chip processing module, described induction coil and the second Differential OPAMP module connect, described second Differential OPAMP module is connected with single chip processing module, described display module, program import module and data derive module and are all connected with single chip processing module, and described power module is powered.
2. earth resistance online monitoring alarm instrument as claimed in claim 1, it is characterised in that also including alarm modules, described alarm modules is made up of broadcasting unit and driver element thereof, and described single chip processing module is connected with the driver element in alarm modules.
3. earth resistance online monitoring alarm instrument as described in claim 1 or 2, it is characterised in that also bag key-press module, described key-press module is connected with single chip processing module.
4. earth resistance online monitoring alarm instrument as claimed in claim 3, it is characterised in that described single chip processing module adopts the single-chip microcomputer of MSP430fl49 model.
5. earth resistance online monitoring alarm instrument as claimed in claim 4, it is characterised in that described data derive module and adopt MAX485 interface chip and RS485 interface.
6. wired remote monitoring system, it is characterized in that, including the earth resistance online monitoring alarm instrument described in claim 5, concentrator and monitoring host computer, the data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, and described concentrator is connected with monitoring host computer by netting twine.
7. wireless remote control system as claimed in claim 6, it is characterised in that described earth resistance metering device and concentrator adopt modbus-rtu communication modes communication.
8. wireless remote control system, it is characterized in that, including the earth resistance online monitoring alarm instrument described in claim 5, concentrator, wireless transmitter, wireless receiver and monitoring host computer, data in described earth resistance metering device are derived module and are connected with concentrator by netting twine, described concentrator is connected by netting twine wireless transmitter, and described wireless receiver is connected with monitoring host computer by netting twine.
9. wireless remote control system as claimed in claim 8, it is characterised in that described wireless transmitter and wireless receiver adopt GSM/GPRS communication modes communication.
CN201610067052.XA 2016-01-29 2016-01-29 Online grounding resistance monitoring alarm and remote monitoring system CN105717366A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201610067052.XA CN105717366A (en) 2016-01-29 2016-01-29 Online grounding resistance monitoring alarm and remote monitoring system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610067052.XA CN105717366A (en) 2016-01-29 2016-01-29 Online grounding resistance monitoring alarm and remote monitoring system

Publications (1)

Publication Number Publication Date
CN105717366A true CN105717366A (en) 2016-06-29

Family

ID=56155472

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610067052.XA CN105717366A (en) 2016-01-29 2016-01-29 Online grounding resistance monitoring alarm and remote monitoring system

Country Status (1)

Country Link
CN (1) CN105717366A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106597213A (en) * 2016-11-11 2017-04-26 华北电力大学(保定) Distributed power transmission and distribution line maintenance operation safety protection digital monitoring system
CN107179444A (en) * 2017-07-19 2017-09-19 国网辽宁省电力有限公司丹东供电公司 Insulating resistance measuring device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2123567A (en) * 1982-06-29 1984-02-01 Redland Automation Ltd A method and apparatus for checking the integrity of a wire
CN202600082U (en) * 2012-04-17 2012-12-12 湖南省电力公司科学研究院 Online device for monitoring operational states of grounding network of power transmission towers
CN202994910U (en) * 2012-12-28 2013-06-12 广州市铱泰电子科技有限公司 On-line detector and system for non-contact grounding resistor
CN103499747A (en) * 2013-09-25 2014-01-08 国家电网公司 Device for online monitoring running state of transformer substation grounding grid
CN204731317U (en) * 2015-06-12 2015-10-28 上海臻和防雷电气技术有限责任公司 A kind of intelligentized earth resistance tester
CN205656241U (en) * 2016-01-29 2016-10-19 南京尚志电子科技有限公司 Ground resistance on -line monitoring alarm and remote monitering system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2123567A (en) * 1982-06-29 1984-02-01 Redland Automation Ltd A method and apparatus for checking the integrity of a wire
CN202600082U (en) * 2012-04-17 2012-12-12 湖南省电力公司科学研究院 Online device for monitoring operational states of grounding network of power transmission towers
CN202994910U (en) * 2012-12-28 2013-06-12 广州市铱泰电子科技有限公司 On-line detector and system for non-contact grounding resistor
CN103499747A (en) * 2013-09-25 2014-01-08 国家电网公司 Device for online monitoring running state of transformer substation grounding grid
CN204731317U (en) * 2015-06-12 2015-10-28 上海臻和防雷电气技术有限责任公司 A kind of intelligentized earth resistance tester
CN205656241U (en) * 2016-01-29 2016-10-19 南京尚志电子科技有限公司 Ground resistance on -line monitoring alarm and remote monitering system

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
曾志海: "《新型双钳式接地电阻测试仪》", 《电动工具》 *
蔡艳丽等: "《基于MSP430的接地电阻在线测量装置的研制》", 《现代科学仪器》 *
陈建明等: "《应用无线传感网络的分布式电力系统接地状态监测》", 《高压电技术》 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106597213A (en) * 2016-11-11 2017-04-26 华北电力大学(保定) Distributed power transmission and distribution line maintenance operation safety protection digital monitoring system
CN106597213B (en) * 2016-11-11 2019-11-19 华北电力大学(保定) Distributed electric line upkeep operation safeguard protection digitized monitoring system
CN107179444A (en) * 2017-07-19 2017-09-19 国网辽宁省电力有限公司丹东供电公司 Insulating resistance measuring device

Similar Documents

Publication Publication Date Title
CN104104456B (en) A kind of low-voltage collecting meter reading communication check device
CN205354304U (en) A communication interface converter for a wide range of strapping table meter
CN104198537B (en) A kind of soil moisture content and conductivity detection method and detection device
CN103217658A (en) Calibration evaluating system and method of partial discharge ultrahigh-frequency detecting device based on GTEM
CN104849649B (en) A kind of detection method of current transformer for metering secondary circuit state
CN103809206A (en) Underground water detection device and detection method based on combination of nuclear magnetic resonance and transient electromagnetic method
CN105467241B (en) A kind of distribution converter transformer DC magnetic bias detecting system and its detection method
CN103529366A (en) UHF (Ultra High Frequency) broadband current sensor based on Rogowski coil principle and joint monitoring system
CN100495074C (en) Nuclear magnetic resonance and transient electromagnetic combined instrument and method
CN101162244B (en) Train insulating resistance testing recorder and testing method
CN102841260A (en) DC microresistivity measuring system
CN201780335U (en) Ground resistance detecting device of overhead transmission line pole tower
CN204166050U (en) Can the anti-electricity-theft intelligent power gauging table of remote meter reading
CN201845051U (en) Three-phase intelligent electric energy meter
CN203100795U (en) Portable power oil consumption tester
CN203337722U (en) Voltage and current collecting device of grid overhead transmission line
CN102597755A (en) Electrical tomography apparatus and method and current driver
CN101266270A (en) Pile foundation tower-footing impedance measuring apparatus and its method
CN203203603U (en) Testing device of radio altimeter
CN102749561B (en) Cloud service-based partial discharge transient-stage earth electric wave cloud detection method and device
CN102914519A (en) Optical fiber type laser liquid turbidity measuring device and measuring method
CN202886514U (en) Direct current (DC) system grounding detector
CN104569902B (en) Digital type electric energy meter power consumption measuring device and method
CN103954815A (en) Electricity larceny prevention check main machine
CN205193212U (en) Insulating detecting system of DC cable

Legal Events

Date Code Title Description
PB01 Publication
C06 Publication
SE01 Entry into force of request for substantive examination
C10 Entry into substantive examination
RJ01 Rejection of invention patent application after publication

Application publication date: 20160629

RJ01 Rejection of invention patent application after publication