Summary of the invention:
In order to overcome existing above-mentioned defect in prior art, the invention provides a kind of method that prevents suspended insulated guide wire ablation;
The technical solution adopted in the present invention is: a kind of method that prevents suspended insulated guide wire ablation, comprises the steps:
S1 sets up suspended insulated guide wire ablation equivalent circuit;
S2 calculates the parameter of described ablation equivalent circuit;
S3 sets up safeguard procedures, and described safeguard procedures are above described insulator, to install metal connecting piece additional for connecting core and the described insulator of described suspended insulated guide wire.
Preferably, the suspended insulated guide wire ablation equivalent circuit of described step S1 comprises the power circuit module, short-term lateral circuit module, insulator circuit module and the long line side circuitry module that connect successively.
Further, described power circuit module comprises AC power AC; Described short-term lateral circuit module comprises resistance R
1, capacitor C
11, capacitor C
01and resistance R
11;
Described resistance R
1with described capacitor C
11one end of parallel branch and one end of described AC power AC be connected, the other end respectively with described capacitor C
01one end and described resistance R
11one end connect;
Described capacitor C
01the other end and the other end ground connection of described AC power AC;
Wherein: R
1the resistance of-conductor cross-section insulating barrier;
R
11the resistance of the suspended insulated guide wire insulation sheath of-short-term side unit length;
C
11the distributed capacitance of the suspended insulated guide wire core of-short-term side unit length to crust;
C
01the suspended insulated guide wire core of-short-term side unit length distributed capacitance over the ground.
Further, described insulator circuit module comprises resistance R
jy; Described resistance R
jyone end and described resistance R
11the other end connect, described resistance R
jyother end ground connection;
Wherein: R
jythe resistance of-insulator.
Further, long line side circuitry module comprises multiple RCC circuit modules that connect successively; Described RCC circuit module comprises capacitor C
12, capacitor C
02and resistance R
12;
The capacitor C of the one RCC circuit module
12one end respectively with the resistance R of a described RCC circuit module
12one end and the capacitor C of a described RCC circuit module
02one end connect; Described resistance R
1and capacitor C
11parallel branch and the link of described AC power AC also with the capacitor C of a described RCC circuit module
12the other end connect; Described resistance R
11with described resistance R
jylink also with the resistance R of a described RCC circuit module
12the other end connect; The capacitor C of a described RCC circuit module
02other end ground connection;
Wherein: C
12the distributed capacitance of the suspended insulated guide wire core of-long line side unit length to crust;
C
02the suspended insulated guide wire core of-long line side unit length distributed capacitance over the ground;
R
12the resistance of the suspended insulated guide wire insulation sheath of-long line side unit length.
Further, the capacitor C of current RCC submodule
12one end respectively with the capacitor C of described current RCC submodule
02one end and the resistance R of described current RCC submodule
12one end connect, described resistance R
1with described capacitor C
11parallel branch and the link of described AC power AC also with the capacitor C of described current RCC submodule
12the other end connect; The capacitor C of described current RCC submodule
02other end ground connection; The resistance R of described current RCC submodule
12the other end and the capacitor C of previous RCC submodule
12and capacitor C
02link connect.
Further, step S2 comprises:
(1) calculate the resistance R of described short-term lateral circuit module of flowing through
11electric current I
1;
I
1=U
1/R
11 (1)
In formula:
U
1-power supply leakage current flow through short-term side suspended insulated guide wire insulation sheath produce voltage;
R
11the resistance of the suspended insulated guide wire insulation sheath of-short-term side unit length;
(2) calculate the resistance R of described long line side circuitry module of flowing through
12electric current I
2;
I
2=U
2/(N×R
12) (2)
U in formula
2-long line lateral capacitance C
12the electrostatic coupling electric current voltage that long line side insulation sheath produces of flowing through;
The length of N-long line side suspended insulated guide wire, the m of unit, N round numbers, N >=7;
R
12the resistance of the suspended insulated guide wire insulation sheath of-unit length;
(3) calculate the described resistance R of flowing through
jyelectric current I
3;
I
3=I
1+I
2; (3)
In formula: I
1the resistance R of-described short-term lateral circuit the module of flowing through
11electric current;
I
2the resistance R of-described long line side circuitry the module of flowing through
12electric current;
Relatively electric current I
1, I
2and I
3size, under filthy condition, U
2< < U
1; Obtain I
2< < I
1, I
3>I
1.
Further, step S3 comprises: select the insulator position of electric current maximum as the enforcement position of safeguard procedures; The safeguard that described safeguard procedures adopt comprises: the support column on vertical direction, steel cap, umbrella insulator body and bracing frame being integrally connected; Described steel crown end along continuous straight runs is provided with the groove of opening upwards; Suspended insulated guide wire crouches in groove; There is a conical metal connecting piece in described bottom portion of groove central authorities, and described metal connecting piece tip punctures the crust of suspended insulated guide wire and the electrical connection of the core of described suspended insulated guide wire; Described groove both sides are provided with interface; Strip fastener two ends are provided with the circular hole corresponding with interface size; Described strip fastener two ends are fixed by the interface of bolt and described groove both sides.
Further, described steel cap is by low side to top, and its horizontal slice is gradually large circle of area; The top of described umbrella insulator body is the circle that area equates with described steel cap bottom area; Described umbrella insulator body is flexibly connected with described steel cap.
Further, the center, top of described umbrella insulator body is provided with tapped interface; Described steel cap bottom center has the be with externally threaded joint corresponding with described interface size; Described steel cap is fixed by joint and described umbrella insulator body.
Further, described groove overlaps with the diameter of described steel crown end end face, and the vertical vertical section of described groove is radius and is slightly larger than the semicircle of described suspended insulated guide wire radius.
Further, described interface is the tapped interface that is symmetrically set in described groove both sides, and two strip fasteners are fixed on described suspended insulated guide wire top, vertical with described suspended insulated guide wire; Described steel emits the distance between center, top and described two strip fasteners to equate and be equal to described steel to emit 1/2nd of top end face radius.
Further, described metal connecting piece and described steel emit one-body molded, and described metal connecting piece and described steel emit and adopt the direct moulding by casting of cast steel material.
The present invention adopts following experimental procedure to verify the protection effect of above-mentioned safeguard procedures:
1, suspended insulated guide wire and the umbellate form insulator of first selecting 10KV, the parameter of the insulator to suspended insulated guide wire is measured, and records suspended insulated guide wire external diameter r
1=17.8mm, conductor cross-section radius a=r
1/ 2=8.9mm, wire conductor wire core diameter r
2=12.6mm, the D=2.6mm of wire outsourcing insulation thickness;
The crust surface area S of the suspended insulated guide wire of unit length
1=2 π aL=559cm
2, L is conductor length, L=1m;
Insulator surface amasss S
2=1090cm
2;
2, calculate suspended insulated guide wire unit length capacitance C over the ground
0i; Wherein
ε is that dielectric constant of air, l are that conductor length, h are wire distance to the ground, and a is wire radius.Calculate as h > > a
By
wherein
for capacitor C
0icorresponding capacitive reactance, f is power distribution network industrial frequency frequency, f=50Hz; Calculate known,
With the capacitance C of capacitance measuring instrument measurement unit length suspended insulated guide wire crust
1i; Record crust capacitance C
1i=418pF/m; According to formula
wherein
for capacitor C
1icorresponding capacitive reactance, f=50Hz is power distribution network industrial frequency frequency, calculates
3, take ash, salt and pure water, this three is reconciled into pasty state, evenly spread upon again surface and the insulator surface of suspended insulated guide wire, the salt close (ESDD) on insulator surface and suspended insulated guide wire surface and ash close (NSDD) are respectively: 0.3mg/cm
2and 2mg/cm
2;
4, intercept unit length wire, being coated with ash close to its external insulation is 2mg/cm
2, salt is close is 0.3mg/cm
2time, the outer surface resistance of the suspended insulated guide wire of measurement unit's length, recording resistance is R
1i=0.6M Ω/m;
5, insulator and suspended insulated guide wire are inserted to humidity and be greater than in 95% mist environment, make the filth of wire and insulator surface make moist saturated; Thereby the residing true environment of simulation suspended insulated guide wire;
6, set up the test model of suspended insulated guide wire according to the equivalent circuit of operating suspended insulated guide wire, as shown in Figure 4: wherein: AC-AC power; T
1-voltage regulator; T
2-step-up transformer; R
1-conductor cross-section insulating barrier resistance; R2-insulator resistance; I
1-short-term side electric current; I
2-long line side electric current; I
3-insulator earth current; The distributed capacitance of the unit length of C1i-insulated conductor core to crust; R
1ithe resistance of-insulated conductor insulation sheath unit length; C
0ithe distributed capacitance of-insulated conductor core unit length over the ground;
In figure, insulator left side is short-term side A section, and right side is long line side B section; Due to Zc
0i> > R
1i, therefore leakage current is mainly from R
1ibranch road is walked; But R
1iincrease and connect with circuit, wire arrives after certain length, very little on the size impact of Leakage Current; In the time of suspended insulated guide wire long enough, meet resistance sum=N rice wire fibre core of N rice wire sheath to crust capacitive reactance sum; Be
wherein N is conductor length; Now wire is long little on test impact again, needn't increase the length of test stand hollow wire, and above-mentioned formula is tried to achieve N=3.6; Consider one times of nargin of suspended insulated guide wire, therefore to get 7 meters of long line side suspended insulated guide wires be the overhead insulating span of alternative true span to this test model, according to the ratio of the long line side of side circuit and short-term side, get the long 1m of suspended insulated guide wire of insulator left side short-term side;
7, according to the test model of setting up, pressurize in short-term side
voltage, with camera record electric arc occur, evolution; Record in the time not adding any safeguard procedures, conditions at the arc are: A section end is even electric spark, plays electric arc with insulator junction, support column place.
8, between step 2 and step 3, add the safeguard procedures that the present invention takes, pressurize in short-term side
voltage, then records electric arc generation, evolution with camera; Recording conditions at the arc is: discharge off.
The present invention has following beneficial effect:
1) the present invention has set up the suspended insulated guide wire equivalent circuit of operation, has obtained its Ablation cause and failure mechanism.
2) according to suspended insulated guide wire Ablation cause and mechanism, propose to prevent the insulator of suspended insulated guide wire ablation, make core direct-furnish insulator leakage current, effectively prevent the ablation of suspended insulated guide wire.
3) metal connecting piece of insulator is chosen as sharp keen taper shape, and this shape is beneficial to while installation and punctures suspended insulated guide wire insulating barrier, and electrical fitting is directly connected with suspended insulated guide wire core, completes electrical connection.
4) the use binding wire of existing suspended insulated guide wire and insulator carries out colligation and fixes, under this mode, electrical fitting is firm not with being connected of suspended insulated guide wire, this insulator uses two strip fasteners to be fixed wire at the upside of wire, can make wire core closely be connected with electrical fitting.
5) insulator steel cap and electrical fitting use the mode of direct moulding by casting, in the time producing insulator steel cap, directly make moulding, and this mode can make electrical fitting and insulator be structure as a whole, make simple, difficult drop-off, easy for installation, cost is low.
Embodiment:
In order to understand better the present invention, below in conjunction with Figure of description and example, content of the present invention is described further:
In order to study the reason of suspended insulated guide wire generation ablation, the present invention has set up equivalent circuit to operating suspended insulated guide wire, as shown in Figure 1: wherein: AC-AC power; R
1the resistance of-conductor cross-section insulating barrier; R
jythe resistance of-insulator; C
11the distributed capacitance of the unit length of-short-term side insulated conductor core to crust; R
11the resistance of-short-term side insulated conductor insulation sheath unit length; C
01the distributed capacitance of-short-term side insulated conductor core unit length over the ground; C
12the distributed capacitance of the unit length of-long line side insulated conductor core to crust; R
12the resistance of-long line side insulated conductor insulation sheath unit length; C
02the distributed capacitance of-long line side insulated conductor core unit length over the ground, wherein, R
11=R
12; C
11=C
12; C
01=C
02.
Analyze known according to Fig. 1: the long line effluent in insulator right side is through resistance R
12electric current be I
2; Insulator left side short-term effluent is through resistance R
11electric current be I
1, the electric current that insulator enters ground is I
3;
Wherein: short-term side resistance R flows through
11electric current I
1=U
1/ R
11, wherein U
1for power supply leakage current flow through short-term side suspended insulated guide wire insulation sheath produce voltage; R
11for the resistance of short-term side suspended insulated guide wire insulation sheath;
Long line side resistance R flows through
12electric current I
2=U
2/ (N × R
12), wherein U
2for long line lateral capacitance C
12the electrostatic coupling electric current voltage that long line side insulation sheath produces of flowing through, N is the length of long line side suspended insulated guide wire; Wherein N>=7;
Described insulator earth current I
3=I
1+ I
2; Under filthy condition, U
2< < U
1, I
2< < I
1, I
3>I
1;
As shown in Figure 2: in order to prevent suspended insulated guide wire ablation, the present invention selects the insulator place of electric current maximum to set up safeguard procedures: the safeguard that safeguard procedures adopt comprises: suspended insulated guide wire, for the insulator of fixing suspended insulated guide wire with for the bracing frame of fixed insulation;
Metal connecting piece is chosen as sharp keen taper shape, and this shape is beneficial to while installation and punctures suspended insulated guide wire insulating barrier, and electrical fitting is directly connected with suspended insulated guide wire core, completes electrical connection.
Insulator steel cap and metal connecting piece use the mode of direct moulding by casting, in the time producing insulator steel cap, directly make moulding, and this mode can make electrical fitting and insulator be structure as a whole, make simply, and difficult drop-off, easy for installation.And the material that metal connecting piece uses is consistent with insulator steel cap, adopt cast steel material.Also electrical fitting can be made separately, be then connected with insulator steel cap by screw or welding, complete making.
As shown in Figure 3: the fixed form of existing suspended insulated guide wire and insulator is for being used binding wire to carry out colligation to it, under this mode, electrical fitting is firm not with being connected of suspended insulated guide wire, this insulator uses two strip fasteners to be fixed wire at the upside of wire, can make wire core closely be connected with electrical fitting.
The conducting wire flow process of safeguard is:
(1) described insulator is connected and fixed by support column and the bracing frame of its bottom;
(2) steel cap and insulator body are fixed;
(2) described suspended insulated guide wire is placed in the groove of square steel cap on described insulator;
(3) strip fastener is installed above suspended insulated guide wire, thus make suspended insulated guide wire be fixed on described steel emit top groove in;
(4) by the bolt tightening at fastener two ends, make metal connecting piece puncture suspended insulated guide wire insulating barrier, make the tip of metal connecting piece and the electrical connection of the fibre core of described suspended insulated guide wire.
The present invention adopts following experimental procedure to verify the protection effect of above-mentioned safeguard procedures:
1, suspended insulated guide wire and the umbellate form insulator of first selecting 10KV, the parameter of the insulator to suspended insulated guide wire is measured, and records suspended insulated guide wire external diameter r
1=17.8mm, conductor cross-section radius a=r
1/ 2=8.9mm, wire conductor wire core diameter r
2=12.6mm, the D=2.6mm of wire outsourcing insulation thickness;
The crust surface area S of the suspended insulated guide wire of unit length
1=2 π aL=559cm
2, L is conductor length, L=1m;
Insulator surface amasss S
2=1090cm
2;
2, calculate suspended insulated guide wire unit length capacitance C over the ground
0i; Wherein
ε is that dielectric constant of air, l are that conductor length, h are wire distance to the ground, and a is wire radius.Calculate as h > > a
By
wherein
for capacitor C
0icorresponding capacitive reactance, f is power distribution network industrial frequency frequency, f=50Hz; Calculate known,
With the capacitance C of capacitance measuring instrument measurement unit length suspended insulated guide wire crust
1i; Record crust capacitance C
1i=418pF/m; According to formula
wherein
for capacitor C
1icorresponding capacitive reactance, f=50Hz is power distribution network industrial frequency frequency, calculates
3, take ash, salt and pure water, this three is reconciled into pasty state, evenly spread upon again surface and the insulator surface of suspended insulated guide wire, the salt close (ESDD) on insulator surface and suspended insulated guide wire surface and ash close (NSDD) are respectively: 0.3mg/cm
2and 2mg/cm
2;
4, intercept unit length wire, being coated with ash close to its external insulation is 2mg/cm
2, salt is close is 0.3mg/cm
2time, the outer surface resistance of the suspended insulated guide wire of measurement unit's length, recording resistance is R
1i=0.6M Ω/m;
5, insulator and suspended insulated guide wire are inserted to humidity and be greater than in 95% mist environment, make the filth of wire and insulator surface make moist saturated; Thereby the residing true environment of simulation suspended insulated guide wire;
6, set up the test model of suspended insulated guide wire according to the equivalent circuit of operating suspended insulated guide wire, as shown in Figure 4: wherein: AC-AC power; T
1-voltage regulator; T
2-step-up transformer; R
1-conductor cross-section insulating barrier resistance; R2-insulator resistance; I
1-short-term side electric current; I
2-long line side electric current; I
3-insulator earth current; The distributed capacitance of the unit length of C1i-insulated conductor core to crust; R
1ithe resistance of-insulated conductor insulation sheath unit length; C
0ithe distributed capacitance of-insulated conductor core unit length over the ground;
In figure, insulator left side is short-term side A section, and right side is long line side B section; Due to Zc
0i> > R
1i, therefore leakage current is mainly from R
1ibranch road is walked; But R
1iincrease and connect with circuit, wire arrives after certain length, very little on the size impact of Leakage Current; In the time of suspended insulated guide wire long enough, meet resistance sum=N rice wire fibre core of N rice wire sheath to crust capacitive reactance sum; Be
wherein N is conductor length; Now wire is long little on test impact again, needn't increase the length of test stand hollow wire, and above-mentioned formula is tried to achieve N=3.6; Consider one times of nargin of suspended insulated guide wire, therefore to get 7 meters of long line side suspended insulated guide wires be the overhead insulating span of alternative true span to this test model, according to the ratio of the long line side of side circuit and short-term side, get the long 1m of suspended insulated guide wire of insulator left side short-term side;
7, according to the test model of setting up, pressurize in short-term side
voltage records electric arc generation, evolution with camera; Record in the time not adding any safeguard procedures, conditions at the arc are: A section end is even electric spark, and electric arc is played at A section and insulator junction, support column place.
8, between step 2 and step 3, add the safeguard procedures that the present invention takes, according to the installation method of safeguard, suspended insulated guide wire and insulator are installed, then pressurize in short-term side
voltage, with camera record electric arc occur, evolution, conditions at the arc are: discharge off.
These are only embodiments of the invention, be not limited to the present invention, within the spirit and principles in the present invention all, any amendment of making, be equal to replacement, improvement etc., within all should being included in the claim scope of the present invention that application awaits the reply.