Summary of the invention:
Defective or deficiency at above-mentioned prior art exists the objective of the invention is to, and a kind of High Voltage XLPE Power Cable joint 7 shelf depreciation vhf band electro-detection capacitive coupled sensors are provided.
The objective of the invention is to overcome the shortcoming of above-mentioned prior art, a kind of partial discharge of high-voltage cable joint on-Line Monitor Device and on-line monitoring method based on capacitive coupled sensors is provided.
Partial discharge of high-voltage cable joint on-Line Monitor Device based on capacitive coupled sensors, comprise computing machine 6, the data acquisition unit 5 that is connected with computing machine 6, first capacitive coupled sensors 1, second capacitive coupled sensors 2, signal condition unit 4 and detection impedance 3, it is characterized in that: first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are arranged on the cable body 16 at cable splice 7 two ends simultaneously, first capacitive coupled sensors 1 is connected by detecting impedance 3 with second capacitive coupled sensors 2, detect in the impedance 3 and be connected with signal condition unit 4 in turn, data acquisition unit 5 and computing machine 6, detecting impedance 3 is used for that the current signal that first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are coupled to is converted to voltage signal and outputs to signal condition unit 4, signal condition unit 4 passes to data acquisition unit 5 after the voltage signal conditioning is amplified, and the voltage signal after 5 pairs of conditionings of data acquisition unit carries out the A/D conversion and outputs to computing machine 6.
First capacitive coupled sensors 1 comprises first insulation course 8, second insulation course 9 and first metal foil electrode 10, first insulation course 8 is close to cable body 16, first insulation course, 8 outer setting, first metal foil electrode 10, first metal foil electrode, 10 outer setting, second insulation course 9, second insulation course, 9 outer setting have the first metal watch chain, 11, the first metal watch chains 11 to be connected with detection impedance 3 left ends.
Second capacitive coupled sensors 2 comprises the 3rd insulation course 12, the 4th insulation course 13 and second metal foil electrode 14, the 3rd insulation course 12 is close to cable body 16, the 3rd insulation course 12 outer setting second metal foil electrode 14, second metal foil electrode, 14 outer setting the 4th insulation course 13, the 4th insulation course 13 outer setting have the second metal watch chain, 15, the second metal watch chains 15 to be connected with detection impedance 3 right-hand members.
Partial discharge of high-voltage cable joint on-line monitoring method based on capacitive coupled sensors, first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are arranged on the cable body 16 at cable splice 7 two ends simultaneously, joint detection impedance 3 between first capacitive coupled sensors 1 and second capacitive coupled sensors 2, in detection impedance 3, connect signal condition unit 4 successively, data acquisition unit 5 and computing machine 6, detecting impedance 3 is used for that the current signal that first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are coupled to is converted to voltage signal and outputs to signal condition unit 4, signal condition unit 4 passes to data acquisition unit 5 after the voltage signal conditioning is amplified, and the voltage signal after 5 pairs of conditionings of data acquisition unit carries out the A/D conversion and outputs to computing machine 6.First insulation course 8 of first capacitive coupled sensors 1 is close to cable body 16, first insulation course, 8 outer setting, first metal foil electrode 10, first metal foil electrode, 10 outer setting, second insulation course 9, second insulation course, 9 outer setting have the first metal watch chain, 11, the first metal watch chains 11 to be connected with detection impedance 3 left ends.The 3rd insulation course 12 of second capacitive coupled sensors 2 is close to cable body 16, the 3rd insulation course 12 outer setting second metal foil electrode 14, second metal foil electrode, 14 outer setting the 4th insulation course 13, the 4th insulation course 13 outer setting have the second metal watch chain, 15, the second metal watch chains 15 to be connected with detection impedance 3 right-hand members.
These High Voltage XLPE Power Cable joint 7 shelf depreciation very high frequency(VHF) on-line monitoring capacitive coupled sensors, by the thick copper product of 0.2mm (or other metal materials) manufactured size is that the metal forming of 110mm * 82mm is as capacitive electrode, draw coupled signal by two bare copper wires, the detection impedance 3 of concentric cable series connection 1k Ω by shielding, thereby current signal is converted to voltage signal, is convenient to gather.
Consider the installation of this sensor, metal foil electrode is placed two-layer electro-insulating rubber, the metal watch chain shape that is concatenated into by long narrow steel disc is fixed on the cable body 16 at cable splice 7 two ends, detects impedance 3 thereby connect the concentric cable series connection by the BNC termination.Because steel disc is to link to each other by screw, so its number can increase and decrease, this makes sensor of the present invention can be applied on the cable of different electric pressures.
The technological approaches that sensor of the present invention adopts is to constitute capacitive electrode by sheet metal is installed on the cable body 16 at cable splice 7 two ends, make its satisfy XLPE cable joint 7 shelf depreciation very high frequency(VHF)s measure with and satisfy following the requirement:
1), compact conformation, do not change cable body 16, on-the-spot easy for installation.
2), (there is good response in the partial discharge pulse of 30MHz~300MHz) to the very high frequency(VHF) component that has of cable splice 7 inside.
3), sensitivity is higher, can be coupled to the discharge pulse signal of cable splice 75pC.
4), be subjected to on-the-spot electromagnetic interference effect less, can avoid the following low-frequency noise influence of 15MHz effectively.
Embodiment:
Below in conjunction with accompanying drawing the present invention is done and to describe in further detail:
Referring to Fig. 1,2,3, partial discharge of high-voltage cable joint on-Line Monitor Device based on capacitive coupled sensors, comprise computing machine 6, the data acquisition unit 5 that is connected with computing machine 6, first capacitive coupled sensors 1, second capacitive coupled sensors 2, signal condition unit 4 and detection impedance 3, it is characterized in that: first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are arranged on the cable body 16 at cable splice 7 two ends simultaneously, first capacitive coupled sensors 1 is connected by detecting impedance 3 with second capacitive coupled sensors 2, detect in the impedance 3 and be connected with signal condition unit 4 in turn, data acquisition unit 5 and computing machine 6, detecting impedance 3 is used for that the current signal that first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are coupled to is converted to voltage signal and outputs to signal condition unit 4, signal condition unit 4 passes to data acquisition unit 5 after the voltage signal conditioning is amplified, and the voltage signal after 5 pairs of conditionings of data acquisition unit carries out the A/D conversion and outputs to computing machine 6.
First capacitive coupled sensors 1 comprises first insulation course 8, second insulation course 9 and first metal foil electrode 10, first insulation course 8 is close to cable body 16, first insulation course, 8 outer setting, first metal foil electrode 10, first metal foil electrode, 10 outer setting, second insulation course 9, second insulation course, 9 outer setting have the first metal watch chain, 11, the first metal watch chains 11 to be connected with detection impedance 3 left ends.
Second capacitive coupled sensors 2 comprises the 3rd insulation course 12, the 4th insulation course 13 and second metal foil electrode 14, the 3rd insulation course 12 is close to cable body 16, the 3rd insulation course 12 outer setting second metal foil electrode 14, second metal foil electrode, 14 outer setting the 4th insulation course 13, the 4th insulation course 13 outer setting have the second metal watch chain, 15, the second metal watch chains 15 to be connected with detection impedance 3 right-hand members.
Partial discharge of high-voltage cable joint on-line monitoring method based on capacitive coupled sensors, first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are arranged on the cable body 16 at cable splice 7 two ends simultaneously, joint detection impedance 3 between first capacitive coupled sensors 1 and second capacitive coupled sensors 2, in detection impedance 3, connect signal condition unit 4 successively, data acquisition unit 5 and computing machine 6, detecting impedance 3 is used for that the current signal that first capacitive coupled sensors 1 and second capacitive coupled sensors 2 are coupled to is converted to voltage signal and outputs to signal condition unit 4, signal condition unit 4 passes to data acquisition unit 5 after the voltage signal conditioning is amplified, and the voltage signal after 5 pairs of conditionings of data acquisition unit carries out the A/D conversion and outputs to computing machine 6.First insulation course 8 of first capacitive coupled sensors 1 is close to cable body 16, first insulation course, 8 outer setting, first metal foil electrode 10, first metal foil electrode, 10 outer setting, second insulation course 9, second insulation course, 9 outer setting have the first metal watch chain, 11, the first metal watch chains 11 to be connected with detection impedance 3 left ends.The 3rd insulation course 12 of second capacitive coupled sensors 2 is close to cable body 16, the 3rd insulation course 12 outer setting second metal foil electrode 14, second metal foil electrode, 14 outer setting the 4th insulation course 13, the 4th insulation course 13 outer setting have the second metal watch chain, 15, the second metal watch chains 15 to be connected with detection impedance 3 right-hand members.
Signal condition unit 4 comprises filtering circuit, and amplifying circuit etc. are realized the processing from the voltage signal of sensor.Select Hi-pass filter elimination low-frequency disturbance, select the cutoff frequency of 5MHz, the major part that makes is disturbed and all is suppressed.Wideband amplification circuit makes that then the faint discharge signal that collects can satisfy the sensitivity requirement of acquisition system.
The collecting unit of native system adopts the PCI-5152 type data collecting card of America NI instrument company, and capture card is installed in the industrial control computer 6, and real-time image data is also carried out the A/D conversion.
The high-speed figure capture card carries out the A/D conversion to the voltage signal from modulate circuit, so that we handle the digital signal of voltage, analyzes.
The major parameter of this capture card is as follows:
● the analog input channel that two-way is 8
● two-way is synchronous, single-end earthed mode
● the analog input bandwidth of 300MHz is optional
● the sampling rate of 1GS/s
● the buffer memory of every passage 64MB
● 50 Ω and the optional input impedance of 1M Ω
● inside/outside triggers optional, and rising/negative edge triggers optional triggering mode
Computing machine 6 adopts industrial control computer 6, the industrial control computer 6 main controls that realize whole observation process, and it comes control signal conditioning unit 4 and signal gathering unit by software, and stores the data that collect so that further analyze.
Native system adopts graphical programming software LabVIEW, database software SQL Server etc. to write cable splice 7 shelf depreciation testing softwares, by demonstration contrast to shelf depreciation different angles parameter, the operation control of realization system, parameter setting, signal Processing, data acquisition and storage, the functions such as line data statistical study, data base administration of going forward side by side.
According to designing requirement, this cover software can be divided into parts such as data acquisition, data processing, spectrum analysis, trend analysis, data preparation and form.
Wherein, part of data acquisition mainly is the setting of finishing the data capture card, such as sampling rate, sampling length, triggering selection and capture card range etc.For this measuring system, sampling rate and sampling length are fixed as 500MS/s and 10M point, and triggering selection is an external trigger, and trigger pip is the power frequency zero cross signal, and the capture card range is adjustable between 10mV ~ 10V according to the size of signal.Acquisition software carries out data acquisition according to the capture card parameter of setting, and the data that collect is delivered to database automatically handle and store.
Referring to Fig. 3, the capacitive coupled sensors equivalent electrical circuit comprises first metallic shield, second metallic shield, capacitor C
1, capacitor C
2, capacitor C
3, capacitor C
4With detection impedance 3zd; Capacitor C
1One end is connected with cable body 16, and the other end is by first metallic shield and capacitor C
2One end connects, capacitor C
2The other end with detect impedance 3Z
dLeft end connects; Capacitor C
3One end is connected with cable body 16, and the other end is by second metallic shield and capacitor C
4One end connects, capacitor C
4The other end with detect impedance 3Z
dRight-hand member connects.
Checking of the present invention
1. laboratory proofing
Experimental subjects is the XLPE cable that has cable splice 7 of a 35kV, and the burr discharge is simulated by acupuncture treatment by cable splice 7 places.The square wave of 5pC is inserted between the core and screen layer of cable, and sensor output signal shows that capacitive coupled sensors of the present invention can be coupled to the discharge pulse of cable splice 75pC.
Remove square wave, the testing transformer output terminal is connected between the core and screen layer of cable, be forced into 5.3kV, from the discharge pulse signal of sensor output as can be seen sensor can be coupled to cable splice 7 shelf depreciations effectively, and spectral response is preferably arranged in 0 ~ 300MHz.
2. on-site verification
System of the present invention is tested on a certain 110kV cable splice 7 of Urumchi, Xinjiang south gate transformer station.Because on-the-spot interference of noise, and the amplitude of local discharge signal own is less, needs by certain signal condition, and obtains effective local discharge signal by software filtering and phase place interference protection measure such as window.
On-the-spot test show system of the present invention can be effectively the shelf depreciation of test cable joint 7 at the scene.
Above content is to further describing that the present invention did in conjunction with concrete preferred implementation; can not assert that the specific embodiment of the present invention only limits to this; for the general technical staff of the technical field of the invention; without departing from the inventive concept of the premise; can also make some simple deduction or replace, all should be considered as belonging to the present invention and determine scope of patent protection by claims of being submitted to.