CN203300352U

CN203300352U - Cable metal sheath circumfluence suppressor with protecting function

Info

Publication number: CN203300352U
Application number: CN201320298611XU
Authority: CN
Inventors: 罗致远; 詹威鹏; 胡力广; 郭伟华; 江克宜; 邬韬; 魏前虎; 李高峰; 王长安; 张有平
Original assignee: Shenzhen Power Supply Bureau Co Ltd
Current assignee: Shenzhen Power Supply Bureau Co Ltd
Priority date: 2013-05-28
Filing date: 2013-05-28
Publication date: 2013-11-20
Anticipated expiration: 2023-05-28

Abstract

A cable metal sheath circumfluence suppressor with a protecting function comprises a zinc oxide valve piece and an inductor (4), wherein the zinc oxide valve piece is connected in parallel with the inductor (4), and the two ends of the zinc oxide valve piece are connected with connecting copper sheets through connecting inverted rods, connecting hardware fittings (1) are connected with the connecting copper sheets, the zinc oxide valve piece, the inductor (4), the connecting inverted rods, the connecting copper sheets and parts of the connecting hardware fittings (1) are poured to be elliptical through epoxy, a rubber sleeve is adopted for sealing by an outer layer, and threaded structures are arranged on the connecting hardware fittings (1), so as to be convenient for connecting other equipment. When electrical current of a wire core is increased, or uniphase short circuit occurs, voltages at the two ends of the inductor (4) are increased, when the voltages excess bearable voltage of a protector, the protector acts, induction current is released to the ground through the protector, the voltages at the two ends of the inductor (4) are clamped in time, and the phenomenon of harm to operating staff and damage caused by inductance heating can be avoided.

Description

A kind of circulation of cable metal sheath with defencive function inhibitor

Technical field

The utility model relates to the protection of power cable sheath and metallic sheath circulation suppresses technical field, the particularly a kind of circulation of cable metal sheath with defencive function inhibitor.

Background technology

in order to adapt to the economic development in city, cable is the characteristics such as high and beautifying city due to stability, cable replaces overhead wire trend gradually in the transmission line of city, particularly 110kV and above grade long-range single core cable use in a large number, thing followed cable fault rate is year after year soaring, accident causes damage huge, cable jacket is the protection of cable outermost layer, also the most easily to be subjected to the outside destroy part, armour is inboard at oversheath, in long distance transmission line, in order to reduce the circulation in induced voltage and loop, after whole circuit is divided into some sections, do once cross interconnected for every three sections, then armour two direct ground connection all, as shown in Figure 1.But the impact due to construction and geographical environment, usually because core load current and three segment length do not wait and other reasons cause sheath induced current increase, cause the sheath heating, thereby reduce cable self load, therefore, in the direct ground connection of cable metal sheath place serial connection circulation inhibitor, be very important.

Retrieval is found, applying date 2004.12.05, application number 200410066049.3, the induced current of power cable sheath inhibition method of application, a kind of method that relates to use inductance balancing electric power cable sheath induced voltage, inhibition circulating current of mentioning in patent of invention, the technical field that belongs to electrical engineering, the method be by threephase cable being divided into three sections, the interconnected ground connection of sheath three-phase of initiating terminal; The two exchange point place cross bondings of each section of threephase cable metal sheath at middle part are connect; According to the cable laying form with lay parameter, calculate the induced voltage on metal sheath, and determine to make the compensating inductance of three-phase voltage balance; Compensating inductance is connected on the 3rd section cable sheath, thereby balance is uneven because the reasons such as renovation of power lines exploitation, cable length change the metal sheath induced voltage that causes, and circulation in cable sheath is reduced greatly.The excessive problem of electric current after this kind mode energy active balance three-phase is cross interconnected, particularly unequal to three segment length due to three-phase, cause final earth current problems of too.but direct ground connection the going out at cable adds an inductance, according to regulation in 10.4 in " Q/CSG_10007-2004_ power equipment preventive trial rules ", interconnected case plug-in strip (perhaps brace) contact resistance and link position inspection, measure in the normal operation service position, contact resistance is not more than 2 μ Ω, the inductance induction reactance of access can be far longer than 2 μ Ω, (inductance two ends) form voltage difference on earth terminal cable cover(ing) earth connection, originally there is no on the earth connection of coilloading electromotive force for can be considered zero potential, but due to inductance of artificial increase, inductance itself can be regarded the series connection of induction reactance and resistance as, owing to there being electric current to pass through, so can form at the inductance two ends very high voltage, computing formula is as follows:

V=I(R+ωL)

With V in following formula---the voltage at inductance two ends

R---inductance self internal resistance

I---current value in cable cover(ing)

ω——2πf

L---institute's coilloading inductance value

According to " People's Republic of China's power industry standard " DL/T5221-2005 standard: while not taking to get the safety measure that can prevent any contacting metal sheath of personnel or screen, in the normal full load situation, must not be greater than 50V, take the safeguard procedures must not be greater than 100V.Particularly in the situation that single-phase short circuit occurs, more than the core electric current can reach 1000A, formed very high voltage at the inductance two ends this moment, and personal safety and inductance itself are caused damage.

Summary of the invention

In order to overcome the defect of above-mentioned prior art; the object of the present invention is to provide a kind of circulation of cable metal sheath with defencive function inhibitor; when power cable works; the electric current that can effectively suppress the cable metal sheath; when the core electric current increases; perhaps when single-phase short circuit occurring; the inductance both end voltage increases; when voltage bears voltage over protector; the protector action; induced current is leaked into the earth by protector, in time clamp down on the voltage at inductance two ends, avoid causing operating personnel to injure and inductance heating damage phenomenon.

In order to achieve the above object, the technical solution of the utility model is:

A kind of circulation of cable metal sheath with defencive function inhibitor; comprise zinc oxide valve plate 5 and inductor 4; zinc oxide valve plate 5 are connected with inductor parallel connection and two ends by connection fall bar 6 be connected copper sheet 3 and connect; connect gold utensil 1 and be connected copper sheet 3 and be connected; zinc oxide valve plate 5, inductor 4, connection bar 6, connection copper sheet 3 and connection gold utensil 1 part pour into ellipse with epoxy 7; the outer rubber sleeve 2 that adopts seals, and connects on gold utensil 1 and is threaded structure.

The utility model is divided into the two large divisions, and the first, be the zinc oxide valve plate 5 of defencive function; Second portion is the inductor 4 that suppresses circulation, is embedded in inductor 4 on the basis to existing protector, and it realizes that technique is first to use the epoxy casting mode two device sealings, and outside is sealed with rubber sleeve 2, and integral body realizes waterproof moisture-proof effect.When the core electric current increases; perhaps when single-phase short circuit occurring; inductor 4 both end voltage increase; when voltage bears voltage over protector; the protector action; induced current is leaked into the earth by protector, in time clamp down on the voltage at inductance two ends, avoid causing operating personnel to injure and inductance heating damage phenomenon.

Description of drawings

Fig. 1 is the utility model structural representation.

Fig. 2 is the one group cross interconnected middle installation site schematic diagram of the utility model protection inhibitor at single core threephase cable.

Embodiment

Illustrate that below in conjunction with the drawings and specific embodiments the utility model is described further.

With reference to Fig. 1; a kind of circulation of cable metal sheath with defencive function inhibitor; comprise zinc oxide valve plate 5 and inductor 4; zinc oxide valve plate 5 are connected with inductor parallel connection and two ends by connection fall bar 6 be connected copper sheet 3 and connect; connect gold utensil 1 and be connected copper sheet 3 and be connected; zinc oxide valve plate 5, inductor 4, connection bar 6, connection copper sheet 3 and connection gold utensil 1 part pour into ellipse with epoxy 7; the outer rubber sleeve 2 that adopts seals; connect on gold utensil 1 and be threaded structure, can conveniently connect other equipment.

the utility model Main Function and operation principle: high voltage single-core cable is when long distance powedr transmission, because induced voltage is crossed high factor and is taked connection segment, every three sections will form one group of cross interconnected loop in a loop line road, as shown in Figure 2, the utility model of direct ground connection place's serial connection in three-phase is cross interconnected, A in principle, B, three sections of C are to equate fully, cross interconnected by three-phase, will offset induced potential fully, earth current is zero, but owing to implementing on-the-spot various conditionalities, cause three segment length inconsistent, perhaps when the load current of three-phase is unequal, can not offset fully by the cross interconnected of three-phase on the oversheath of cable, form cable metal sheath circulation, sometimes electric current is excessive and cause sheath heating serious, reduce the ability to transmit electricity of cable itself, therefore by the utility model of direct ground connection place's serial connection cross interconnected, can effectively suppress circulation, the effect of zinc oxide valve plate 5 is, when single-phase earthing fault occurring, flowing through the cable metal sheath induced voltage increases, instantaneous circulation increases, then form very high voltage at the two ends of inductance,, in order to be unlikely to burn inductance, more avoid causing maintainer's injury owing to forming high pressure at the inductance two ends, utilize zinc oxide valve plate 5 protective effects, in time forming high pressure, in time be conducting to earth terminal.Two device cooperatings, reach and namely suppressed cable bushing circular current, accomplishes again the double effects of being protected.

Claims

1. the circulation of the cable metal sheath with defencive function inhibitor, it is characterized in that, comprise zinc oxide valve plate (5) and inductor (4), zinc oxide valve plate (5) is connected 4 with inductor) parallel connection and two ends by connection fall bar (6) be connected copper sheet (3) and connect, connect gold utensil (1) and be connected copper sheet (3) and be connected, zinc oxide valve plate (5), inductor (4), connect to fall bar (6), connect copper sheet (3) and connect gold utensil (a 1) part and pour into ellipse with epoxy (7), the outer rubber sleeve (2) that adopts seals, connect on gold utensil (1) and be threaded structure.