A kind of cable insulation ageing tester based on higher hamonic wave
Technical field
The utility model relates to electron electric power equipment technical field, specifically a kind of cable insulation based on higher hamonic wave is old
Change test device.
Background technique
With the fast development of electric power network technique, twisted polyethylene cable (abbreviation XLPE) has good electrical property and hot
Can, and structure is simple, and the manufacturing cycle is short, and work tolerable temperature is high, and oil-free, laying is convenient, and power supply safety is reliable, is conducive to beauty
Change city, thus is widely used in each voltage class of electric system.But the insulation knot of twisted polyethylene cable
In structure often due in processing technology difficulty or raw material are impure and there are air gap and harmfulness impurity, or due to technique
Reason between insulation and semiconductive shielding layer there are gap or semiconductor are prominent to insulating layer, in these air gaps and impurity point
Shelf depreciation is easily generated at end, while may also can be generated various insulation in the installation and operation process of power cable and be lacked
Falling into leads to shelf depreciation.Shelf depreciation is the sign of cable insulation deterioration, and causes the one of the major reasons of insulation degradation, office
Portion's electric discharge is the running biggish security risk of power cable, if shelf depreciation development will cause to a certain extent
Insulation breakdown and cause power grid accident.Therefore, have to power cable and its connector progress cable insulation burn-in test important
Meaning and economic value.
Utility model content
The purpose of this utility model is to provide a kind of cable insulation ageing tester based on higher hamonic wave, to solve
The problem of being proposed in background technique.To achieve the above object, the utility model provides the following technical solutions;
A kind of cable insulation ageing tester based on higher hamonic wave, the cable insulation aging based on higher hamonic wave
Test device includes variable-frequency power sources, transformer, reactor, divider, compensation circuit, high-pass filter and wave detector, the electricity
Anti- device and cable constitute series resonant tank, and the variable-frequency power sources is connect with a 220V voltage, and the 220V voltage passes through described
Exported after variable-frequency power sources frequency modulation, by it is described it is transformer coupled after be conveyed to the series resonant tank, to provide frequency conversion resonance vibration
Resonance potential, the resonance potential is added to the reactor and cable and constitutes in series resonant tank, make the reactor with
The cable resonance, the high-pass filter are connected in parallel on the cable ends, humorous in the series resonant tank for extracting
Shake signal, and the higher hamonic wave in the resonance signal is delivered to the wave detector, and the wave detector is by the higher hamonic wave
It carries out envelope detection and obtains rectified signal, whether hit by the insulating layer that the amplitude of the rectified signal obtains the cable
It wears;
The transformer includes that the first winding L1 and the first winding L2, the circle number of the first winding L1 are less than described first
The circle number for winding L2, by the 220V boost in voltage, the divider parallel connection on the cables, for testing the cable
On resonance potential, and as overvoltage crowbar, the divider includes first capacitor C1 and the second capacitor C2, described first
Capacitor C1 and the second capacitor C2 are in parallel, and the compensation circuit includes compensating electric capacity C3, and the compensating electric capacity C3 and the cable are simultaneously
Connection, for compensating the capacitor of the cable;
The equivalent inductance of the reactor is L, and the equivalent capacity after the compensating electric capacity C3 is in parallel with the cable is C,
Resonance frequency is ω, and as ω L=1/ ω C, the series resonant tank starts resonance.
Preferably, the transformer by the 220V boost in voltage to more than is equal to 10KV, to apply on the cables
High voltage keeps the insulation of fault location breakdown.
Preferably, the reactor is the equal single-unit reactor B composition of 3 section parameters, single-unit reactor B's described in every section
Inductance value is 55H, and resistance is 385 Europe, plays the role of pressurization, makes circuit resonance.
Preferably, the transformation ratio of the transformer is 1:5, and full output is 248V, by the boost in voltage of 220V to 248V.
Preferably, the resonance frequency of the series resonant tank changes in the range of 30HZ-300HZ, a variety of to complete
The insulation ag(e)ing of cable is tested.
Preferably, the cable is in paper insulated cable, rubber plastics-insulated power cable and exchange polyethylene insulated cable
One or more, in the present embodiment, the cable is rubber plastics-insulated power cable, and the scope of application is wider.
Compared with prior art, the utility model has the beneficial effects that the utility model will not cause brokenly cable insulation
It is bad, and for the aging of cable entirety and more serious local defect sensitivity all with higher, so actually answering
It is with a wide range of applications in, it is simple and fast, facilitate implementation, detection sensitivity is high, can more accurately reflect electricity
The insulation ag(e)ing situation of cable reduces unplanned power outage so that the maintenance and replacement for cable run provide reference.
Detailed description of the invention
Fig. 1 is a kind of structural representation of the cable insulation ageing tester provided by the utility model based on higher hamonic wave
Figure;
Fig. 2 is the circuit diagram of the cable insulation ageing tester provided by the utility model based on higher hamonic wave;
Wherein, variable-frequency power sources 1, transformer 2, reactor 3, divider 4, compensation circuit 5, high-pass filter 7, wave detector 8.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical aspect in the utility model embodiment
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work
Every other embodiment obtained, fall within the protection scope of the utility model.
Fig. 1-Fig. 2 is please referred to, a kind of embodiment provided by the utility model:
A kind of cable insulation ageing tester based on higher hamonic wave, the cable insulation aging based on higher hamonic wave
Test device includes variable-frequency power sources 1, transformer 2, reactor 3, divider 4, compensation circuit 5, high-pass filter 7 and wave detector 8,
The reactor 3 constitutes series resonant tank with cable 6, and the variable-frequency power sources 1 is connect with a 220V voltage, the 220V voltage
By exporting after 1 frequency modulation of variable-frequency power sources, it is conveyed to the series resonant tank after coupling by the transformer 2, to mention
For the resonance potential of frequency conversion resonance vibration, the resonance potential is added to the reactor 3 and constitutes in series resonant tank with cable 6, makes
The reactor 3 and 6 resonance of cable, the high-pass filter 7 is connected in parallel on 6 both ends of cable, for extracting the string
Join the resonance signal in resonant tank, and the higher hamonic wave in the resonance signal is delivered to the wave detector 8, the detection
Higher hamonic wave progress envelope detection is obtained rectified signal by device 8, obtains the cable 6 by the amplitude of the rectified signal
Insulating layer it is whether breakdown;
The transformer 2 includes that the first winding L1 and the first winding L2, the circle number of the first winding L1 are less than described the
The circle number of one winding L2, by the 220V boost in voltage, the divider 4 is connected in parallel on the cable 6, described for testing
Resonance potential on cable 6, and as overvoltage crowbar, the divider 4 includes first capacitor C1 and the second capacitor C2, institute
State first capacitor C1 and the second capacitor C2 be in parallel, the compensation circuit 5 includes compensating electric capacity C3, the compensating electric capacity C3 with it is described
Cable 6 is in parallel, for compensating the capacitor of the cable 6;
The equivalent inductance of the reactor 3 is L, and the equivalent capacity after the compensating electric capacity C3 is in parallel with the cable 6 is
C, resonance frequency ω, as ω L=1/ ω C, the series resonant tank starts resonance.
In the present embodiment, the transformer 2 is by the 220V boost in voltage to more than is equal to 10KV.
In the present embodiment, the reactor 3 is the equal single-unit reactor B composition of 3 section parameters, single-unit reactance described in every section
The inductance value of device B is 55H, and resistance is 385 Europe.
In the present embodiment, the transformation ratio of the transformer 2 is 1:5, and full output is 248V.
In the present embodiment, the resonance frequency of the series resonant tank changes in the range of 30HZ-300HZ.
In the present embodiment, the cable 6 is paper insulated cable, rubber plastics-insulated power cable and exchange polyethylene insulated cable
One of or it is a variety of.
Working principle: the voltage after coupling is conveyed to the series resonant tank, the resonance potential by the transformer 2
It is added to the reactor 3 to constitute in series resonant tank with cable 6, as ω L=1/ ω C, the series resonant tank starts
Resonance, to provide the resonance potential of frequency conversion resonance vibration, the resonance potential can be established in the minor insulation fault location of cable 6 higher more to be collected
In field strength, the voltage between winding inter-turn, interlayer and section meets and exceeds the breakdown voltage at dielectric defect, and gives cable
6 apply frequency more than several times of rated frequency, and higher frequency can substantially reduce the breakdown voltage of solid dielectric again, make
Insulation defect it is more easily breakdown, and within certain action time can guarantee cable 6 insulation defect it is breakdown, the height
Bandpass filter 7 extracts the resonance signal in the series resonant tank, and the higher hamonic wave in the resonance signal is delivered to
The wave detector 8, the wave detector 8 obtain rectified signal, obtain the insulation of the cable 6 by the amplitude of the rectified signal
Whether layer is breakdown, to reliably detect the quality of transformer longitudinal insulation performance.
Although the utility model is described in detail with reference to the foregoing embodiments, come for those skilled in the art
Say, it is still possible to modify the technical solutions described in the foregoing embodiments, or to part of technical characteristic into
Row equivalent replacement, within the spirit and principle of the utility model, any modification, equivalent replacement, improvement and so on should all
It is included within the scope of protection of this utility model.