CN205248761U - Single core cable cross -bonding case - Google Patents

Abstract

The utility model relates to a single core cable cross -bonding case, a serial communication port, include: the sheath protector, cross -bonding connecting wire and connecting in parallel at every condenser on the sheath protector, wherein, the one end of cross -bonding connecting wire is connected to respectively each looks of single core cable, the other end is connected to every respectively the one end of sheath protector, every the other end ground connection of sheath protector. The utility model discloses a single core cable cross -bonding case, when carrying out the range finding of trouble travelling wave, transmission completely can be realized through the condenser to single core cable's trouble travelling wave signal, avoids cross -bonding department signal to roll over the reflection to realize single core cable's trouble travelling wave range finding completely.

Description

The cross interconnected case of a kind of single-core cable

Technical field

The utility model relates to power equipment detection technique field, especially relates to a kind of single core electricityThe cross interconnected case of cable.

Background technology

Along with the raising that technological progress and power supply quality require, power cable is shared in electrical networkRatio is increasing, has progressively replaced overhead transmission line in the urban district in some cities. Along with cableIncreasing and the prolongation of running time of quantity, the generation of cable fault is further frequent. How accurately,The position of failure point of judging rapidly power cable is to repair in time power cable, raising power supply reliablyThe premise of property.

The localization of fault of power cable, generally need to carry out fault diagnosis, fault localization and essenceDetermine three steps of point. Wherein, fault diagnosis can be undertaken by high-potting; PinpointGeneral audio frequency or other frequency induction technologies of adopting. Fault localization is also named fault bigness scale, refers toThe one or both ends of cable are used suitable instrument, and failure cable core is applied to test signal,Or on-line measurement, analysis of failure information, the distance of certain one end is arrived in the preliminary localization of faults, forPinpoint provides range information. The fault distance-finding method of power cable is a lot, can divide generallyFor traveling wave method and impedance method two classes, according to cable running status, be divided into again off-line range finding or onlineRange finding. In order to find efficiently and accurately power cable fault point, reduce the quantities such as ground excavationAnd power off time, traveling wave fault location technology is widely used.

Traveling wave method utilizes high voltage to carry out electrical breakdown to cable fault, measures the disruptive discharge of fault placeThe time of electric pulse from trouble point to test point just can calculate trouble point distance. Traveling wave fault is surveyedApart from the impact that is not subject to the factors such as trouble point transition resistance, line construction, and range accuracy is high, because ofThis has obtained application more widely.

Conventionally 35kV and following power cable and control communication cable adopt three cores or multicore (lowPiezoelectric forces cable or the increase neutral conductor, protective wire etc. become four-core, five-core cable) structure, electricityThe outside resultant magnetic field of core a little less than, can adopt magnetic protection material. Cable intermediate joint screenCover protective layer conventionally directly connected and earth-free, transition joint wave impedance changes very little, therefore,Cable total length wave impedance is substantially constant, and transition joint is non-to the catadioptric of fault localization travelling wave signalA little less than normal, do not affect identification and the judgement of signal. Travelling wave ranging method at the above power cable of three cores andControl in communication cable and be widely used, and utilize while operation by the cable damagingWeak discharge signal, developed online range finding or claimed cable early warning technology.

35kV and above power cable, owing to manufacturing and construction reason, generally adopt single-core cable,Especially power cable more than 110kV. For longer power cable, for fear of protecting outwardLayer punctures, and relevant code requires longer power cable line, and cable should be divided into 3 multiple section,Screen layer carries out cross interconnected in each transition joint, by protector ground connection, as Fig. 1 instituteShow, cross interconnected connecting line 10 is by sheath protector 20 ground connection, to ensure screen layer induced electricityPressure is no more than 50V, and reduces overvoltage injury. According to analysis, single-core cable transition joint placeAfter screen layer is cross interconnected, is equivalent in theory cable insulation electric field and connects with air electric field,Wave impedance alters a great deal. Therefore, can there is serious catadioptric in transition joint place in travelling wave signal,Traditional travelling wave ranging technology cannot be realized. On-the-spot practical experience shows, from test pointGo, the trouble point after first transition joint, travelling wave ranging instrument can be judged as position of failure pointBe first transition joint, travelling wave ranging method is actually and cannot applies for single-core cable,Comprise online and off-line.

Utility model content

Based on the problems referred to above, the utility model provides a kind of single-core cable cross interconnected case, is enteringWhen row fault travelling wave ranging, the fault traveling wave signal of single-core cable can be realized by capacitor entirelyLine transmission, avoids cross interconnected place signal catadioptric, thereby realizes the fault all fronts of single-core cableTravelling wave ranging.

For realizing above-mentioned utility model object, the utility model provides a kind of single-core cable to intersectInterconnected case, is characterized in that, comprising: sheath protector, cross interconnected connecting line and alsoBe associated in the capacitor on each described sheath protector;

Wherein, one end of described cross interconnected connecting line is connected respectively to described single-core cableEach phase, the other end is connected respectively to one end of each described sheath protector, each described inThe other end ground connection of sheath protector.

Wherein, described cross interconnected case also comprises casing, described in described casing is used for holding, protectsLayer protector, cross interconnected connecting line and described capacitor.

Wherein, described cross interconnected connecting line comprises cross connect sheet, described cross connect sheetOne end be connected on the metal sheath of each phase of single-core cable, described in the other end is connected toSheath protector.

Wherein, on described casing, be provided with cable link, being positioned at of described cable linkOne end of box house is connected to described cross interconnected connecting line, is positioned at one end of casing outsideBe connected to described single-core cable.

Cross interconnected case of the present utility model, in the time carrying out fault travelling wave ranging, owing to makingDuring with cross interconnected case, between cable and ground, be connected with capacitor, thereby make single core electricityThe fault traveling wave signal of cable can be realized transmission completely by capacitor, avoids cross interconnected placeSignal catadioptric, thus realize the fault travelling wave ranging completely of single-core cable.

Brief description of the drawings

Can more clearly understand feature and advantage of the present utility model, accompanying drawing by reference to accompanying drawingSchematically to should not be construed as the utility model is carried out to any restriction, in the accompanying drawings:

Fig. 1 shows the connection diagram of the existing cross interconnected case of the utility model.

Fig. 2 shows the connection diagram of cross interconnected case of the present utility model.

Fig. 3 shows the connection diagram of sheath protector of the present utility model and electric capacity.

Fig. 4 shows the schematic diagram of travelling wave ranging of the present utility model.

Detailed description of the invention

Below in conjunction with accompanying drawing, embodiment of the present utility model is described in detail.

Fig. 2 shows the connection diagram of cross interconnected case of the present utility model.

With reference to Fig. 2, the cross interconnected case of single-core cable of an embodiment of the utility model, concreteComprise: cross interconnected connecting line 10, sheath protector 20 and capacitor 30;

In the present embodiment, one end of cross interconnected connecting line 10 is connected respectively to single-core cableEach phase, the other end is connected respectively to one end of each sheath protector 20, each sheathThe other end ground connection of protector 20.

In the present embodiment, cross interconnected case also comprises casing, and this casing is used for holding sheathProtector, cross interconnected connecting line and described capacitor.

In addition, cross interconnected connecting line comprises cross connect sheet, one end of this cross connect sheetBe connected on the metal sheath of each phase of single-core cable, the other end is connected to described sheath and protectsProtect device.

Based on above-mentioned cross connect sheet, on casing, be also provided with cable link, this cableOne end that is positioned at box house of link is connected to the interconnection of this cross interconnected connecting lineSheet, the one end that is positioned at casing outside is connected on the metal sheath of each phase of single-core cable.

In another embodiment, use after above-mentioned cross interconnected case stube cable, OKIn ripple when range finding,, traveling wave ranging device can adopt single-ended or both-end, online or off-line, onceOr multiple pulses, DC pulse or AC sine wave or hybrid waveform voltage etc.; Capacitor connectsConnect and adopt homophase screen layer to connect. Fig. 3 shows sheath protector of the present utility model and electricityThe connection diagram of holding. As shown in Figure 3, in parallel respectively at the two ends of each sheath protectorA capacitor C11～C13, then one end A1～C1 of each sheath protector is connected to friendshipPitch interconnected connecting line, other end ground connection.

In technique scheme, the Capacity Selection of capacitor makes for travelling wave signal, impedanceClose to 0; For line-frequency induction voltage or test frequency voltage, as the wave of oscillation or frequency conversion testPower supply, impedance is relatively large, to avoid affecting the normal operation of cable or trystate.

Particularly, in cable wave impedance Z_c=50 Ω, power frequency f₀=50Hz and row ripple lowest frequencyf_wUnder=10kHz condition, condenser capacity is selected:

Very little to row ripple frequency impedance,As get 0.05Z_cI.e. 2.5 Ω,Capacitor

$C\≥\frac{1}{2{\mathrm{\πf}}_w\×0.05Z_c}=\frac{1}{2\×3.1416\×10\×{10}^3\×0.05\×50}=6.4\mathrm{\μ}F$

For power frequency impedance, condenser impedance

$X_{c0}=\frac{1}{2{\mathrm{\πf}}_{0}C}=\frac{1}{2\×3.1416\×50\×6.4\×{10}^{-6}}=1k\mathrm{\Ω}$

Maximum capacitor electric current, calculates according to maximum induced voltage 50V

$I_{c0}=\frac{U}{X_{c0}}=\frac{50}{1000}=50mA$

Capacitor is very little for the impedance of cable fault travelling wave signal, and for power frequency componentImpedance is very large, can meet equivalent circuit as shown in Figure 4, makes the intersection of transition jointInterconnected wave impedance Z_AChange by short circuit, fault traveling wave signal can pass through smoothly.

The cable of the cross interconnected case of the present embodiment is installed in sum, can uses existingTravelling wave ranging technology and equipment can realize single-core cable transition joint cross interconnected online orOff-line fault localization, therefore to be applied to any existing traveling wave ranging device.

Cross interconnected case of the present utility model, in the time carrying out fault travelling wave ranging, owing to makingDuring with cross interconnected case, between cable and ground, be connected with capacitor, thereby make single core electricityThe fault traveling wave signal of cable can be realized transmission completely by capacitor, avoids cross interconnected placeSignal catadioptric, thus realize the fault travelling wave ranging completely of single-core cable.

Above detailed description of the invention is only in order to illustrate concrete enforcement technical scheme of the present utility modelAnd unrestricted, although the utility model is had been described in detail with reference to example, the skill of this areaArt personnel should be appreciated that can the technical solution of the utility model be modified or is equal to and replaceChange, and do not depart from the spirit and scope of technical solutions of the utility model, it all should be encompassed in this realityIn the middle of novel claim scope.

Claims (4)

1. the cross interconnected case of single-core cable, is characterized in that, comprising: sheath protector, cross interconnected connecting line and be connected in parallel on the capacitor on each described sheath protector;

Wherein, one end of described cross interconnected connecting line is connected respectively to each phase of described single-core cable, and the other end is connected respectively to one end of each described sheath protector, the other end ground connection of each described sheath protector.

2. cross interconnected case according to claim 1, is characterized in that, described cross interconnected case also comprises casing, and described casing is used for holding described sheath protector, cross interconnected connecting line and described capacitor.

3. cross interconnected case according to claim 1; it is characterized in that; described cross interconnected connecting line comprises cross connect sheet, and one end of described cross connect sheet is connected on the metal sheath of each phase of described single-core cable, and the other end is connected to described sheath protector.

4. cross interconnected case according to claim 2, it is characterized in that, on described casing, be provided with cable link, one end that is positioned at box house of described cable link is connected to described cross interconnected connecting line, and the one end that is positioned at casing outside is connected to described single-core cable.