CN203117262U - Online detector for leakage current of surge protection device (SPD) - Google Patents
Online detector for leakage current of surge protection device (SPD) Download PDFInfo
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- CN203117262U CN203117262U CN 201320068435 CN201320068435U CN203117262U CN 203117262 U CN203117262 U CN 203117262U CN 201320068435 CN201320068435 CN 201320068435 CN 201320068435 U CN201320068435 U CN 201320068435U CN 203117262 U CN203117262 U CN 203117262U
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- leakage current
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Abstract
The utility model discloses an online detector for leakage current of an SPD, which comprises a flexible Rogowski coil, an operational amplifier, a voltage follower and a display device. The flexible Rogowski coil is connected with the SPD as well as to the ground, the operational amplifier is connected with the flexible Rogowski coil, the voltage follower is connected with the operational amplifier, and the display device is connected with the voltage follower. According to the utility model, the circuit structure is simple, number reading is visual, and operation is convenient; the flexible Rogowski coil is employed, measurement is convenient, contact is not direct, and work is safe; a compensation circuit is used, and measuring precision is improved; circuit work is stable in performance, high in sensitivity and wide in measuring scope; and circuit power consumption is low, so that the detector can be directly supplied by a chargeable battery.
Description
Technical field
The utility model belongs to the thunder and lightning science and technology field, particularly a kind of device of online detection surge protection leakage current.
Background technology
The mid-80 China uses surge protector (SPD) in electric power system in large quantities from 20th century, and important effect is being brought into play in the inhibition of lightning surge and switching overvoltage.When using surge protector, majority is to be done specially for core part by the non-linear part of Zinc-oxide piezoresistor (MOV), and the MOV device has superior characteristics: characteristics such as big, the non-linear characteristics of through-current capacity are good, no afterflow.But because the effect that MOV will bear System Operation voltage for a long time, SPD can send out the variation that valve block can take place, humidity, and the effect of factors such as filth and superpotential increases the power of SPD and the magnitude of current, and deterioration can take place in chip, even causes blast, phenomenon on fire.Given to show great attention at these phenomenons in the society, in order in time to find making moist of MOV, oxidation and other hidden danger, avoid the massive losses that caused by accident, improving the MOV reliability of products, when strengthening quality control, it is very effective means that MOV is carried out online detection and condition diagnosing.The advantage of SPD being carried out online detection is not need to cut off the power supply just can have gained some understanding to its performance, and can find its hidden danger and defective, makes things convenient for the staff in time to remedy, and avoids guaranteeing that becoming economic loss SPD normally moves.Every year, meteorological competent authorities before thunderstorm season will detect SPD, the project that detects mainly is that outward appearance and off-line device detect, also having the static parameter to SPD is that reference voltage and leakage current check, these inspections can not illustrate the actual conditions of SPD fully, at the leakage current that should increase on the basis of this test item under the effect of SPD on-Line Voltage, can in time reflect the ruuning situation of SPD truly.Its leakage current under the working voltage effect is mainly measured in the online detection of the leakage current of SPD.Because Leakage Current can reflect the operation conditions of SPD to a great extent.By online detection, not only can find fault as best one can, fix a breakdown, perfect the safe operation system of SPD: and the SPD Leakage Current added up and realizes data analysis, thereby detect the inherent vice of SPD effectively, it is significant therefore SPD to be carried out online detection.
The utility model content
The purpose of this utility model is in order to overcome the problems referred to above, a kind of device of online detection surge protection leakage current to be provided.
For achieving the above object; the method that the utility model adopts is: a kind of device of online detection surge protection leakage current; comprise flexible Luo-coil, operational amplifier, voltage follower and display device; described flexible Luo-coil links to each other with surge protector and ground connection; described operational amplifier links to each other with flexible Luo-coil; voltage follower links to each other with operational amplifier, and display device links to each other with voltage follower.
As a kind of improvement of the present utility model, described flexible Luo-coil also is connected with an electronic compensation circuit.
As a kind of improvement of the present utility model, described electronic compensation circuit comprises amplifying circuit, phase-shift circuit, filtering circuit and V/I change-over circuit.
The beneficial effects of the utility model are:
1, circuit design is simple, and reading is directly perceived, is convenient to operation.
2, flexible Luo-coil, it is convenient to measure, non-direct contact, work safety.
3, the design of flexible Luo-coil is adopted compensating circuit, the measuring accuracy height.
4, circuit working stable performance, highly sensitive, can measure the leakage current of 0～mA level, measurement range is big.
5, circuit power consumption is little, directly adopts rechargeable battery powered.
Description of drawings
Fig. 1 is structured flowchart of the present utility model;
Fig. 2 is the schematic diagram of Luo-coil of the present utility model;
Fig. 3 is electronic compensation circuit diagram of the present utility model;
Fig. 4 is the schematic diagram of amplifying circuit of the present utility model;
Fig. 5 is the schematic diagram of phase-shift circuit of the present utility model;
Fig. 6 is the schematic diagram of filtering circuit of the present utility model;
Fig. 7 is the schematic diagram of circuit of the present utility model;
Fig. 8 is circuit diagram of the present utility model;
Embodiment
Below in conjunction with accompanying drawing the utility model is done specific description.
The device of a kind of online detection surge protection leakage current as described in Figure 1; comprise flexible Luo-coil, operational amplifier, voltage follower and display device; described flexible Luo-coil links to each other with surge protector and ground connection; described operational amplifier links to each other with flexible Luo-coil; voltage follower links to each other with operational amplifier, and display device links to each other with voltage follower.
As a kind of improvement of the present utility model, described flexible Luo-coil also is connected with an electronic compensation circuit.
The principle of flexible Luo-coil is current sensor.The error of current sensor mainly is to produce owing to exciting curent exists, therefore in order to reduce the error of current sensor.At present, the most direct mode reduces exciting curent exactly, when exciting curent in the current sensor is zero, that is to say that magnetic core has reached " zero magnetic flux " state, at this moment it is the linearity range that is operated in magnetization curve, the output of current sensor is just received can not free distortion, can guarantee good linearty, and ratio and angular difference are zero.Flexible Luo-coil uses the external electrical compensating circuit dynamically to follow the tracks of exciting curent in the iron core in design, has carried out compensation simultaneously again and has made the magnetic flux in the chip dynamically approach zero.
Be illustrated in figure 2 as the schematic diagram of Luo-coil of the present utility model, wherein N
1And N
2Be respectively once, the secondary winding, N
0For detecting winding, N
3For the compensation winding, when not compensating, I
1N
1+ I
2N
2=I
0N
1, L magnetic potential balance equation is I in the iron core after adding electronic compensation
1N
1+ I '
2N
2+ I
3N
3=I '
0N
1, I '
2For adding the current value that compensation back secondary is surveyed, I
3Be by detecting winding N
0In induced potential regulate through the compensate for electronic circuit and obtain, exciting curent has certain relation, I ' in its size and the iron core
0For exciting current in the iron core behind the adding compensated line, regulate electronic circuit and can satisfy I
3N
3=I '
0N
1, this moment I
1N
1+ I '
2N
2=0, N
1And N
2Formed zero-flux current transformer.The magnetic permeability of iron core is more high, then the error of mutual inductor is more little, precision is more high, in order to measure little electric current, the initial survey magnetic permeability of core material is the bigger the better, and adopts the cost performance height, stability preferably super microcrystallizing alloy material as core material, it is single turn that the number of turn is got a number of turn, and the secondary number of turn is got the 100-200 circle, and magnetic permeability is got (5-6) * 10
4R gets 510 Ω.
Be illustrated in figure 3 as electronic compensation circuit diagram of the present utility model, described electronic compensation circuit comprises amplifying circuit, phase-shift circuit, filtering circuit and V/I change-over circuit.
Be illustrated in figure 4 as the schematic diagram of the amplifying circuit in the electronic compensation circuit of the present utility model, select single amplifier integrated circuit TL061 for use, it with the precision height, low in energy consumption, frequency of operation is wide and use advantages such as simple, only uses an outer meeting resistance to measure amplification, the amplification scope is from 1～1000 times.
Be illustrated in figure 5 as the schematic diagram of the phase-shift circuit in the electronic compensation circuit of the present utility model, phase-shift circuit be to change V
1Phase place, regulate to be input to compensation winding N
3In electric current I
3Phase place, use the constant amplitude phase-shift circuit here.
Work as R
1=R
fThe time, frequency characteristic is A
i=V
0/ V
i=(R+jx)/(R-jx)=(R
2-x
2)/(R
2+ x
2)+j * (2Rx)/(R
2+ x
2), x=1/wc wherein, amplitude versus frequency characte A
v=1, amplitude versus frequency characte φ=-π-arctan ((2Rx)/(R
2-x
2)), when selecting different R for use, during C, can regulate phase angle φ in the variation of-180 ° to-360 ° scope.
Be illustrated in figure 6 as the schematic diagram of the filtering circuit in the electronic compensation circuit of the present utility model, adopt the quadravalence low-pass filter, circuit diagram is shown in Figure 6.According to the method for designing of quadravalence low-pass filter, when cutoff frequency was 200Hz, each parameter value was: R
1=30k Ω, R
2=62k Ω, R
3=12k Ω, R
4=27k Ω, C
1=6800pF, C
2=510pF, C
3=390pF, C
4=510pF.
Fig. 7 is the schematic diagram of the V/I change-over circuit in the electronic compensation circuit of the present utility model, and described V/I change-over circuit is made of two spaning waveguide operational amplifiers (OTA), wherein
I
3Be V/I change-over circuit output current; V
yBe V/I switching current discrepancy voltage, I
B1, I
B2Be OTA1, the bias current of OTA2, the biasing resistor of establishing OTA1 is R
B1, the biasing resistor of OTA2 is R
B2, I
B2/ I
B1=R
B1/ R
B2, can choose reasonable R
B1, R
B2And Z
xThe adjusting V/I of value between conversion coefficient.
Fig. 8 is circuit diagram of the present utility model, and wherein R is the integrating resistor of flexible Luo-coil, I
C1, I
C2By the rp-op amp that LM358 constitutes, I
C3Constitute voltage follower, output signal voltage is directly delivered to the voltage table gauge outfit and is shown, reads the size of leakage current value by the calibration counting.
The course of work of the present utility model is: obtain leakage current values with flexible Luo-coil from the ground connection of SPD, utilize the principle of electric current correspondence that leakage current is coupled on the secondary coil, the voltage of secondary coil output directly shows leakage current values through follower I through after the amplification of integrating resistor.Amplifier, phase shift, filtering, V I constitute the electronic compensation circuit, offset current intensity is to reduce the measuring error of current transformer.This principle can directly detect the leakage current of MOA, judges the running status of MOA according to size.Deterioration takes place SPD and when making moist, resistive Leakage Current increases, and when current ratio increases by 1～2 times in the past, or when surpassing 20mA, will think to reach dangerous edge.
The device of a kind of online detection surge protection leakage current of the present utility model, circuit design is simple, and reading is directly perceived; be convenient to operation, by adopting flexible Luo-coil, it is convenient to measure; non-direct contact, work safety adopts compensating circuit; improved measuring accuracy; and the circuit working stable performance, highly sensitive, measurement range is big; circuit power consumption is little, can directly adopt rechargeable battery powered.
The above; it only is preferred embodiment of the present utility model; be not to be the restriction of the utility model being made any other form, and according to any modification or equivalent variations that technical spirit of the present utility model is done, still belong to the utility model scope required for protection.
Claims (3)
1. the device of an online detection surge protection leakage current; it is characterized in that: comprise flexible Luo-coil, operational amplifier, voltage follower and display device; described flexible Luo-coil links to each other with surge protector and ground connection; described operational amplifier links to each other with flexible Luo-coil; voltage follower links to each other with operational amplifier, and display device links to each other with voltage follower.
2. the device of a kind of online detection surge protection leakage current according to claim 1, it is characterized in that: described flexible Luo-coil also is connected with an electronic compensation circuit.
3. the device of a kind of online detection surge protection leakage current according to claim 2, it is characterized in that: described electronic compensation circuit comprises amplifying circuit, phase-shift circuit, filtering circuit and V/I change-over circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320068435 CN203117262U (en) | 2013-02-05 | 2013-02-05 | Online detector for leakage current of surge protection device (SPD) |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320068435 CN203117262U (en) | 2013-02-05 | 2013-02-05 | Online detector for leakage current of surge protection device (SPD) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203117262U true CN203117262U (en) | 2013-08-07 |
Family
ID=48897597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320068435 Expired - Fee Related CN203117262U (en) | 2013-02-05 | 2013-02-05 | Online detector for leakage current of surge protection device (SPD) |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203117262U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616549A (en) * | 2013-11-29 | 2014-03-05 | 国家电网公司 | Broadband low-current measurement device based on isolated PCB-type Rogowski coil |
| CN103983830A (en) * | 2014-04-23 | 2014-08-13 | 南京信息工程大学 | Automatic-monitoring switch type surge protective device afterflow device |
| CN104345196A (en) * | 2014-10-30 | 2015-02-11 | 南京信息工程大学 | Active weak power frequency current induction coil |
| CN105606963A (en) * | 2015-11-23 | 2016-05-25 | 国网上海市电力公司 | Test circuit for measuring high-frequency leakage current of cable |
| CN108802537A (en) * | 2018-07-09 | 2018-11-13 | 安徽诚意电气科技有限公司 | A kind of intelligent detecting method of Surge Protector |
-
2013
- 2013-02-05 CN CN 201320068435 patent/CN203117262U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616549A (en) * | 2013-11-29 | 2014-03-05 | 国家电网公司 | Broadband low-current measurement device based on isolated PCB-type Rogowski coil |
| CN103983830A (en) * | 2014-04-23 | 2014-08-13 | 南京信息工程大学 | Automatic-monitoring switch type surge protective device afterflow device |
| CN103983830B (en) * | 2014-04-23 | 2016-06-08 | 南京信息工程大学 | The device of a kind of automatic monitoring slowdown monitoring switch type surge protector afterflow |
| CN104345196A (en) * | 2014-10-30 | 2015-02-11 | 南京信息工程大学 | Active weak power frequency current induction coil |
| CN105606963A (en) * | 2015-11-23 | 2016-05-25 | 国网上海市电力公司 | Test circuit for measuring high-frequency leakage current of cable |
| CN108802537A (en) * | 2018-07-09 | 2018-11-13 | 安徽诚意电气科技有限公司 | A kind of intelligent detecting method of Surge Protector |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130807 Termination date: 20150205 |
|
| EXPY | Termination of patent right or utility model |