CN108120859B - Active electromagnetic shielding generating device - Google Patents
Active electromagnetic shielding generating device Download PDFInfo
- Publication number
- CN108120859B CN108120859B CN201711474039.7A CN201711474039A CN108120859B CN 108120859 B CN108120859 B CN 108120859B CN 201711474039 A CN201711474039 A CN 201711474039A CN 108120859 B CN108120859 B CN 108120859B
- Authority
- CN
- China
- Prior art keywords
- resistor
- amplifier
- capacitor
- power supply
- electromagnetic
- 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
- 239000003990 capacitor Substances 0.000 claims description 55
- 238000012360 testing method Methods 0.000 description 7
- 230000001052 transient effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000036039 immunity Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/18—Screening arrangements against electric or magnetic fields, e.g. against earth's field
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Amplifiers (AREA)
- Filters And Equalizers (AREA)
Abstract
The invention discloses an active electromagnetic shielding generating device, wherein the non-inverting input end of an amplifier U1A is respectively connected with one end of R2 and one end of C2, the other end of R2 is sequentially connected with one ends of R5, R4 and R1 in series, the other end of C2 is connected with one end of C1, the other end of C1 is connected with the other end of R1 and then is connected with a constant voltage source V1, and the output end of the amplifier U1A is respectively connected with the inverting input end and one end of R3; the non-inverting input end of the amplifier U2A is respectively connected with the other end of the R3 and one end of the R6, the other end of the R6 is grounded, the output end of the amplifier U2A is respectively connected with one end of the R8, one end of the C3, one end of the C4 and the inverting input end of the amplifier U2A, the other end of the C3 is connected between the R4 and the R5 after being connected with the other end of the C4, the other end of the R8 is connected with one end of the R7, and the other end of the R7 is connected between the C2 and the C1. The invention breaks through the traditional electromagnetic passive shielding type electromagnetic interference removing mode, and reduces and suppresses the electromagnetic environment interference mode by using the active electromagnetic generation mode.
Description
Technical Field
The invention belongs to the technical field of electromagnetic field anti-interference, and particularly relates to an active electromagnetic shielding generating device.
Background
Under the condition that shielding is not carried out, the electronic equipment is affected by strong electromagnetic interference sources such as direct lightning or indirect lightning, so that the equipment cannot work or works abnormally, damage occurs in the worst case, the phenomenon is more common electromagnetic interference appearance, and the other phenomenon is that when a user strikes a mine, he listens to a radio to watch a television, a computer is used, the radio generates 'creak' noise, the television and the computer generate image shake and the like, and the electromagnetic interference is caused by interference generated by lightning.
The high-voltage test equipment, the control equipment and other metering and monitoring equipment of the transformer substation should ensure safe and reliable operation. However, the electromagnetic environment of the transformer substation is complex and changeable, and whether the equipment can meet the requirement of the electromagnetic environment of the high-voltage transformer substation is uncertain. Therefore, in field test or operation, a relatively clean space is needed for providing electromagnetic environment for the devices, so that the devices can work safely and normally, and the stability and safety of the operation of the devices in the transformer substation are ensured.
The microcomputer protection device, the measurement and control device, the instrument and the like of the power system or the system is a core control part of the power system. In order to ensure safe and stable operation of the power system, a device or system put into use in the power system needs to meet the requirements of electromagnetic compatibility standards and pass an electromagnetic immunity test in a table. However, the on-site electromagnetic environment interference condition of the power system is complex, and firstly, the frequency components are various, and the power frequency electromagnetic interference is the main factor; but rather strong non-other operating ratios of electromagnetic interference. The device or system is most severely interfered by transient electromagnetic interference such as electric fast transient pulse group disturbance and lightning wave caused by switching operation. So that a typical device or system must pass an electrical fast transient burst immunity test and a surge immunity test before being put into operation, it is necessary to provide a relatively gentle or even a clear electromagnetic space in the field of operation.
Therefore, the development of the electromagnetic clean space generator has important significance for the field test of the electric power system or the environment of long-term operation of important equipment, and the research of the electromagnetic clean space generator enables an independent space to have measures for resisting the disturbance of the electric fast transient pulse group, so that the electromagnetic clean space generator has important significance for improving the electromagnetic environment where the device and the system are positioned, enhancing the disturbance resistance performance of the electromagnetic clean space generator, effectively inhibiting the disturbance of the electric fast transient pulse group to the electromagnetic clean space generator, ensuring the reliable operation of the device or the system and ensuring the safe and stable operation of the electric power system.
Through implementing the erection of electromagnetic environment clean space generator in the transformer substation, realize carrying out electromagnetic isolation and electromagnetic protection to the secondary equipment such as test and special control, measurement of use in the transformer substation, make its work in the electromagnetic environment space of relative cleanness, guarantee its safe and steady operation, strengthen the further improvement of transformer substation's equipment operation stability and security, reach maximum application effect and economic benefits.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an active electromagnetic shielding generating device which can effectively inhibit information of a certain frequency or a plurality of frequencies in an input signal under the condition of ensuring that signals of other frequencies are not lost, thereby removing interference electromagnetic signals in a space environment.
In order to solve the problems in the prior art, the invention discloses an active electromagnetic shielding generating device, which comprises: the amplifier comprises an amplifier U1A, an amplifier U2A, resistors R1-R8 and capacitors C1-C4;
the non-inverting input end of the amplifier U1A is respectively connected with one end of a resistor R2 and one end of a capacitor C2, the other end of the resistor R2 is sequentially connected with one end of a resistor R5, one end of a resistor R4 and one end of a resistor R1 in series, the other end of the capacitor C2 is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with the other end of the resistor R1 and then is connected with a constant voltage source V1, and the output end of the amplifier U1A is respectively connected with the inverting input end of the amplifier U1A and one end of the resistor R3; the positive electrode of the power supply of the amplifier U1A is connected with the power supply VCC, and the negative electrode of the power supply is grounded;
the non-inverting input end of the amplifier U2A is respectively connected with the other end of the resistor R3 and one end of the resistor R6, the other end of the resistor R6 is grounded, the output end of the amplifier U2A is respectively connected with one end of the resistor R8, one end of the capacitor C3, one end of the capacitor C4 and the inverting input end of the amplifier U2A, the other end of the capacitor C3 is connected between the resistor R4 and the resistor R5 after being connected with the other end of the capacitor C4, the other end of the resistor R8 is connected with one end of the resistor R7, and the other end of the resistor R7 is connected between the capacitor C2 and the capacitor C1; the positive power supply pole of the amplifier U2A is connected with the power supply VCC, and the negative power supply pole is grounded.
As a preferred scheme, the resistor R1, the resistor R2, the resistor R8 and the resistor R3 are all the same in resistance, the resistor R4, the resistor R5 and the resistor R6 are all the same in resistance, the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are all the same in capacitance, and the sum of the resistance of the resistor R7 and the resistor R8 is equal to one half of the sum of the resistance of the resistor R1 and the resistance of the resistor R4.
Preferably, the resistances of the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R5, the resistor R6, the resistor R7 and the resistor R8 are respectively 5.1kΩ, 91kΩ, 43kΩ and 5.1kΩ, the capacitance values of the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are 33nF, the voltage of the power supply VCC is 5V, the voltage of the constant voltage source V1 is 100mV, and the frequency is 50Hz.
Preferably, the model of the amplifier U1A and the model of the amplifier U2A are AD8602ARM.
As a preferred scheme, the output end of the amplifier U1A is also respectively connected with the positive electrode end of the oscilloscope and the positive electrode output end of the Bode display instrument, the negative electrode input end of the oscilloscope is grounded, the positive electrode input end of the Bode display instrument is connected with a constant voltage source, and the negative electrode input end and the negative electrode output end are grounded.
Preferably, the oscilloscope is XSC1, and the Bode display is XDP1.
The invention has the beneficial effects that:
1. the invention adopts the operational amplifier and some simple resistance-capacitance devices to realize the trap wave generation mode of electromagnetic interference, can well inhibit the electromagnetic interference, and is convenient and simple to use.
2. The operational amplifier, the resistor, the capacitor and other devices adopted by the invention are the most common devices and equipment in the electronic material market, not only can realize electromagnetic anti-interference, but also can ensure that the device is convenient to manufacture, produce and select materials, is easy to manufacture, and has low power consumption, simple structure and high sensitivity.
3. The invention breaks through the traditional electromagnetic passive shielding type electromagnetic interference removing mode, and adopts the active electromagnetic generation mode to reduce and inhibit the electromagnetic environment interference mode, and directly adopts simple common components and materials to process and realize, so that the device has small volume, light weight and low price, and is easier to widely use and popularize.
Drawings
FIG. 1 is a schematic diagram of the occurrence of the present invention;
FIG. 2 is a graph of amplitude-frequency characteristics of the present invention;
FIG. 3 is a circuit diagram of a preferred embodiment of the present invention;
fig. 4 is an analysis chart of electromagnetic suppression effect of the embodiment shown in fig. 3.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
As shown in FIG. 1, the generation principle of the active electromagnetic shielding generation device mainly comprises three parts, namely a frequency selection part, an amplifier part and a feedback part. A dual T-shaped band reject filter implemented by means of a two-stage operational amplifier and a resistor-capacitor is based and incorporates voltage controlled feedback.
The node current equation (1) for point a has:
(U i -U A )sC+(U 0 -U A )sC+(mU 0 -U A )2n＝0 (1)
similarly, for point B, the node current equation (2) has:
(U i -U B )n+(U 0 -U B )n+(mU 0 -U B )sC＝0 (2)
likewise, there is a node current equation (3) for point C:
(U A -U 0 )sC+(U B -U 0 )n＝0 (3)
in the middle of
The transfer function of this circuit can be obtained from the above equations (1), (2) and (3) as follows:
let s=jω get
Wherein the method comprises the steps of
When ω=ω 0 When G (j omega) =0, filteringFor other frequencies, G (jω) is about 1, which can well pass signals of other frequencies. Let G (jω) =0.707 give two cut-off frequencies:
and
The bandwidth BW of the trap and its Q value are then obtained as follows:
BW＝f H -f L ＝4(1-m)f 0 and (b)
Therefore, when m is about 1, the Q value is extremely high, and BW is close to zero, so that the bandwidth can be adjusted by changing the value of m, the larger the Q value is, the narrower the band-stop curve is, the better the wave-limiting effect is, and the amplitude-frequency characteristic is shown in figure 2.
Based on the above principle, a specific circuit connection manner for obtaining a preferred embodiment of the present invention is shown in fig. 3, and an active electromagnetic shielding generating device includes: the amplifier comprises an amplifier U1A, an amplifier U2A, resistors R1-R8 and capacitors C1-C4; the non-inverting input end of the amplifier U1A is respectively connected with one end of a resistor R2 and one end of a capacitor C2, the other end of the resistor R2 is sequentially connected with one end of a resistor R5, one end of a resistor R4 and one end of a resistor R1 in series, the other end of the capacitor C2 is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with the other end of the resistor R1 and then is connected with a constant voltage source V1, and the output end of the amplifier U1A is respectively connected with the inverting input end of the amplifier U1A and one end of the resistor R3; the positive power supply pole of the amplifier U1A is connected with the power supply VCC, and the negative power supply pole is grounded.
The non-inverting input end of the amplifier U2A is respectively connected with the other end of the resistor R3 and one end of the resistor R6, the other end of the resistor R6 is grounded, the output end of the amplifier U2A is respectively connected with one end of the resistor R8, one end of the capacitor C3, one end of the capacitor C4 and the inverting input end of the amplifier U2A, the other end of the capacitor C3 is connected between the resistor R4 and the resistor R5 after being connected with the other end of the capacitor C4, the other end of the resistor R8 is connected with one end of the resistor R7, and the other end of the resistor R7 is connected between the capacitor C2 and the capacitor C1; the positive power supply pole of the amplifier U2A is connected with the power supply VCC, and the negative power supply pole is grounded.
Based on the principle, to make f 0 When the values of m are close to 1, the resistances of the resistors R1, R2, R3, R4, R5, R6, R7 and R8 are 5.1kΩ, 91kΩ, 43kΩ and 5.1kΩ, the values of the capacitors C1, C2, C3 and C4 are 33nF, the voltage of the power supply VCC is 5V, the voltage of the constant voltage source V1 is 100mV, and the frequency is 50Hz. The model numbers of the amplifier U1A and the amplifier U2A are AD8602ARM.
Capacitors C1-C4, resistors R1, R2, R4, R5, R7 and R8 are used to determine the center frequency f 0 The frequency values to be filtered out can be selected by varying these resistances and capacitances.
The resistors R3 and R6 are used for determining the value of m, and can control the filtering characteristics, including the frequency bandwidth of the band-stop filter and the level of the Q value. The amplifier U1A is used as an amplifier, and the output end of the amplifier U1A is used as the output of the whole circuit; the amplifier U2A is used as a voltage follower and forms a voltage feedback circuit with an output end, positive feedback is introduced into the circuit, and when the signal frequency tends to zero, the positive feedback is weak because the impedance of the capacitor tends to infinity; when the frequency of the signal is high, the 7 th node voltage tends to zero because the impedance of the capacitor is small at this time. The amplification factor is increased at the center frequency point as long as positive feedback is properly introduced, and self-excitation oscillation does not occur.
As shown in fig. 4, the output end of the amplifier U1A is further connected to the positive end of the oscilloscope and the positive output end of the baud display respectively, the negative electrode of the oscilloscope is grounded, the positive input end of the baud display is connected to the constant voltage source, and the negative electrode input end and the negative electrode output end are grounded. The model of the oscilloscope is XSC1, and the model of the Bode display is XDP1. A50 hz sine signal source is added at the signal source end of the circuit, the circuit is switched on to start simulation, a Bode display XDP1 and an oscilloscope XSC1 are turned on, a simulation Bode diagram can be obtained, the oscilloscope displays a power frequency signal which can well inhibit 50hz at the moment, the Bode display shows that the center frequency of a trap is 50.003hz, and the trap attenuates at-38.835 dB, so that the filter designed by the invention is a narrow-band filter, has a very high Q value, and can accurately filter the designated frequency.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.
Claims (4)
1. An active electromagnetic shielding generating device is characterized in that: comprising the following steps: the amplifier comprises an amplifier U1A, an amplifier U2A, resistors R1-R8 and capacitors C1-C4;
the non-inverting input end of the amplifier U1A is respectively connected with one end of a resistor R2 and one end of a capacitor C2, the other end of the resistor R2 is sequentially connected with one end of a resistor R5, one end of a resistor R4 and one end of a resistor R1 in series, the other end of the capacitor C2 is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with the other end of the resistor R1 and then is connected with a constant voltage source V1, and the output end of the amplifier U1A is respectively connected with the inverting input end of the amplifier U1A and one end of the resistor R3; the positive electrode of the power supply of the amplifier U1A is connected with the power supply VCC, and the negative electrode of the power supply is grounded;
the non-inverting input end of the amplifier U2A is respectively connected with the other end of the resistor R3 and one end of the resistor R6, the other end of the resistor R6 is grounded, the output end of the amplifier U2A is respectively connected with one end of the resistor R8, one end of the capacitor C3, one end of the capacitor C4 and the inverting input end of the amplifier U2A, the other end of the capacitor C3 is connected between the resistor R4 and the resistor R5 after being connected with the other end of the capacitor C4, the other end of the resistor R8 is connected with one end of the resistor R7, and the other end of the resistor R7 is connected between the capacitor C2 and the capacitor C1; the positive electrode of the power supply of the amplifier U2A is connected with the power supply VCC, and the negative electrode of the power supply is grounded;
the model numbers of the amplifier U1A and the amplifier U2A are AD8602ARM;
the output end of the amplifier U1A is also respectively connected with the positive electrode end of the oscilloscope and the positive electrode output end of the Bode display instrument, the negative electrode end of the oscilloscope is grounded, the positive electrode input end of the Bode display instrument is connected with a constant voltage source, and the negative electrode input end and the negative electrode output end of the Bode display instrument are both grounded.
2. An active electromagnetic shield generator according to claim 1, wherein: the resistor R1, the resistor R2, the resistor R8 and the resistor R3 are all the same in resistance, the resistor R4, the resistor R5 and the resistor R6 are all the same in resistance, the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are all the same in capacitance, and the sum of the resistance of the resistor R7 and the resistor R8 is equal to one half of the sum of the resistance of the resistor R1 and the resistance of the resistor R4.
3. An active electromagnetic shield generator according to claim 2, wherein: the resistances of the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R5, the resistor R6, the resistor R7 and the resistor R8 are respectively 5.1kΩ, 91kΩ, 43kΩ and 5.1kΩ, the capacitance values of the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are 33nF, the voltage of the power supply VCC is 5V, the voltage of the constant voltage source V1 is 100mV, and the frequency is 50Hz.
4. An active electromagnetic shield generator according to claim 1, wherein: the model of the oscilloscope is XSC1, and the model of the Bode display is XDP1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711474039.7A CN108120859B (en) | 2017-12-29 | 2017-12-29 | Active electromagnetic shielding generating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711474039.7A CN108120859B (en) | 2017-12-29 | 2017-12-29 | Active electromagnetic shielding generating device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108120859A CN108120859A (en) | 2018-06-05 |
| CN108120859B true CN108120859B (en) | 2024-04-12 |
Family
ID=62232224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711474039.7A Active CN108120859B (en) | 2017-12-29 | 2017-12-29 | Active electromagnetic shielding generating device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108120859B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110686805B (en) * | 2019-10-17 | 2020-11-24 | 西安建筑科技大学 | Method and circuit for calibrating temperature signal of double reheat steam of thermal power plant |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203812186U (en) * | 2014-05-20 | 2014-09-03 | 浙江知祺电力自动化有限公司 | Microprocessor management circuit of self-powered microcomputer protection device |
| CN104391192A (en) * | 2014-11-11 | 2015-03-04 | 深圳市南航电子工业有限公司 | Anti-electromagnetic interference capacitive oil mass measuring method and system thereof |
| CN204597979U (en) * | 2015-04-29 | 2015-08-26 | 北京唯得科技有限公司 | Intelligent whole frequency band mobile phone shielding system |
| CN205120900U (en) * | 2015-11-09 | 2016-03-30 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Submarine cable direct current partial discharge detector probe |
| CN105738786A (en) * | 2016-03-30 | 2016-07-06 | 合肥工业大学智能制造技术研究院 | GIS ultrahigh frequency partial discharge signal collection device which shields external interface |
| CN205374572U (en) * | 2015-12-31 | 2016-07-06 | 保定华创电气有限公司 | Capacitive equipment earth current sampling device |
| CN105973495A (en) * | 2016-05-09 | 2016-09-28 | 武汉天富海科技发展有限公司 | Device used for measuring temperature of high voltage power electronic equipment |
| CN207851122U (en) * | 2017-12-29 | 2018-09-11 | 国网江苏省电力有限公司检修分公司 | A kind of active electric magnetic screen generating means |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034551B2 (en) * | 2001-09-06 | 2006-04-25 | Tokyo Electron Limited | Electrostatic capacitance detection circuit and microphone device |
| TW591236B (en) * | 2001-09-06 | 2004-06-11 | Sumitomo Metal Industry Ltd | Impedance detector circuit and static capacitance detector circuit |
-
2017
- 2017-12-29 CN CN201711474039.7A patent/CN108120859B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203812186U (en) * | 2014-05-20 | 2014-09-03 | 浙江知祺电力自动化有限公司 | Microprocessor management circuit of self-powered microcomputer protection device |
| CN104391192A (en) * | 2014-11-11 | 2015-03-04 | 深圳市南航电子工业有限公司 | Anti-electromagnetic interference capacitive oil mass measuring method and system thereof |
| CN204597979U (en) * | 2015-04-29 | 2015-08-26 | 北京唯得科技有限公司 | Intelligent whole frequency band mobile phone shielding system |
| CN205120900U (en) * | 2015-11-09 | 2016-03-30 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Submarine cable direct current partial discharge detector probe |
| CN205374572U (en) * | 2015-12-31 | 2016-07-06 | 保定华创电气有限公司 | Capacitive equipment earth current sampling device |
| CN105738786A (en) * | 2016-03-30 | 2016-07-06 | 合肥工业大学智能制造技术研究院 | GIS ultrahigh frequency partial discharge signal collection device which shields external interface |
| CN105973495A (en) * | 2016-05-09 | 2016-09-28 | 武汉天富海科技发展有限公司 | Device used for measuring temperature of high voltage power electronic equipment |
| CN207851122U (en) * | 2017-12-29 | 2018-09-11 | 国网江苏省电力有限公司检修分公司 | A kind of active electric magnetic screen generating means |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108120859A (en) | 2018-06-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2015032343A1 (en) | Testing system of gis electronic mutual inductor and method therefor | |
| CN108471124B (en) | Resonance suppression method for photovoltaic inverter to be connected into alternating current-direct current hybrid micro-grid | |
| CN106771648A (en) | A kind of capacitance current of distribution network measuring method based on improvement signal injection method | |
| CN103487679A (en) | AIS electronic transformer testing system and testing method thereof | |
| CN108120859B (en) | Active electromagnetic shielding generating device | |
| CN102496909B (en) | Simple leakage protector with multi-gear adjustable protection values and action time | |
| CN203502581U (en) | AIS electronic transformer test system based on disconnecting switch switching-on and switching-off capacitive small current | |
| CN108233873A (en) | A kind of multi-channel noise simulation generator | |
| CN104682929B (en) | Pulse signal duty cycle measurement circuit | |
| CN105958510B (en) | SOC chip for power grid monitoring and control equipment | |
| CN108594158B (en) | Differential mode interference test device and method | |
| CN207851122U (en) | A kind of active electric magnetic screen generating means | |
| CN108919166A (en) | Signal of CVT based on deconvolution principle restores new method | |
| Coenen et al. | ‘Live’mains impedance measurement and analysis | |
| CN204462210U (en) | based on the damped oscillation generator of electronic switch | |
| CN205792213U (en) | Turbine flow converter capable of resisting transient high voltage | |
| CN204101639U (en) | A kind of lightning impulse earth loop impedance test instrument | |
| Wu et al. | A novel protection scheme for VSC‐HVDC transmission lines based on current integral autocorrelation | |
| CN202696463U (en) | Power supply filter capable of inhibiting overvoltage surge | |
| Bei et al. | Research on measurement accuracy of EVT during the surge | |
| Bai et al. | Passivity enhancement by series LC filtered active damper with zero current reference | |
| CN202696153U (en) | Potent power supply filter | |
| CN207396596U (en) | Non-isolated multichannel three-phase mains voltage detection circuit | |
| CN204758702U (en) | Utilize adjustable volume arc suppressing coil to measure device of electric wire netting direct -to -ground capacitance | |
| CN205195543U (en) | Rod control system's power supply unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |