CN103022945A - Method for mounting jumper wire of power transmission line tension-resisting tower - Google Patents

Abstract

The invention provides a method for mounting a jumper wire of a power transmission line tension-resisting tower. The method comprises the following steps of: step 1: measuring a jumper wire chord length l, a high angle difference of two suspension points of the jumper wire and a jumper wire adjusting sag f; step 2: obtaining a lead wire compression joint correction factor a and a lead wire distance adjusting value b; step 3: substituting l, f and a into a relation formula (1) between a wire length and the sag to generate a jumper wire length L; and step 4: cutting a lead wire according to the jumper wire length L, arranging the cut lead wire on the ground in a compression joint manner and mounting on the tower. According to the method for mounting the jumper wire of the power transmission line tension-resisting tower provided by the invention, compression joint revision, sag revision and line corner revision treatment are carried out, so that the length of the jumper wire can be accurately measured and the efficiency of mounting the jumper wire is improved.

Description

A kind of strain tower of transmission line wire jumper installation method

Technical field

The invention relates to the transmission line mounting technique, particularly about a kind of strain tower of transmission line wire jumper installation method.

Background technology

The strain tower wire jumper mounting process of transmission line is a large technical barrier that affects construction quality and operating efficiency always.Wire jumper on the strain tower is as the part of transmission line, and the size of its sag directly affects the safe and stable operation of circuit.When the construction sag during sag, causes then that the clearance for insulation between wire and cross-arm is inadequate less than design; When larger, affected by windage yaw after, can cause the clearance for insulation of body of the tower too small, cause the reduction of line insulation level.Therefore, the precision of wire jumper length is very remarkable on the impact of transmission line construction.

For the wire jumper of span on the strain tower between several meters to more than 20 meters, its tension force is little, conductor rigidity is large on the impact of its bending, the in addition impact of the many factors such as the corner number of degrees of the angle of wire clamp (starting point of wire), the gradient that has or not supporting insulator, insulator string, circuit, cause the variation of wire jumper form, therefore, although designing unit has provided the wire jumper installation length, and still there is larger error between the actual wire jumper sag of measuring after installing and design sag.

At present, for wire jumper install that most units in charge of construction take be on-the-spot amount than simulation, it is an end of first crimping wire jumper, it is suspended from the tower, by comparison, definite line length that prints, then at ground intercepting wire, the crimping lead wire other end, at last installation forming again.Whole installation process needs twice work high above the ground, and operation is loaded down with trivial details, and efficient is lower, but also can cause a certain amount of wire waste.

In order to simplify work progress, reduce amount of high-altitude operation, guarantee fail safe, to improve construction quality, demand studying a kind of assembled wire jumper installation method that considers on-the-spot each factor affecting urgently, thereby reach the purpose that improves efficiency of construction, reducing construction cost, upgrades technologies, alleviates workmen's labour intensity.

Summary of the invention

The invention provides a kind of strain tower of transmission line wire jumper installation method, with accurate measurement wire jumper line length, the strain tower wire jumper of finishing of precise and high efficiency is made and mounting process.

To achieve these goals, the invention provides a kind of strain tower of transmission line wire jumper installation method, the method comprises: step 1: the high angular difference of measuring wire jumper chord length l, wire jumper two hitch points

And wire jumper is adjusted sag f; Step 2: obtain conductor compression jointing length correction coefficient a and separation adjusted value b; Step 3: with described l,

Relational expression (1) between f and a substitution line length and the sag generates the long L of wire jumper,

Step 4: according to the long L intercepting of wire jumper wire, carry out installing on the tower behind the described wire of crimping intercepting on the ground.

Further, without jumping the string situation, after step 3, described method also comprises for strain tower: the sag in the relational expression (1) is revised according to following formula (2) or formula (3),

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\max }---\left(2\right)$

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\min }---\left(3\right)$

Then correction value f* substitution relational expression (4) is obtained the long L of wire jumper, wherein, f _MaxFor the wire jumper maximum is allowed sag permissible value, f _MinFor the wire jumper minimum is allowed sag permissible value L=L ₁+ L ₂+ L ₃

Further, for strain tower single-hop string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁And l ₂, respectively with l ₁And l ₂Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the second wire jumper ₂, L=L ₁+ L ₂

Further, for strain tower double jump string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁, l ₃And the double bounce string in the middle of hanging hole apart from l ₂, respectively with l ₁And l ₃Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the 3rd wire jumper ₃, with l ₂Relational expression below the substitution (4) obtains the long L of the second wire jumper ₂.

Further, when f/l＜0.23, the sag in the relational expression between line length and the sag is revised according to formula (2).

Further, as f/l〉0.23 the time, the sag in the relational expression between line length and the sag is revised according to formula (3).

Further, for strain tower single-hop string situation, ${\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HDA00002442908400041.png"\; state="\{\{state\}\}">l</figure-callout>}}_1=\mathrm{MQ}=\sqrt{{\mathrm{MP}}^2+{\mathrm{QP}}^2-2\mathrm{MP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}},$ $l_2=\mathrm{NQ}=\sqrt{{\mathrm{NP}}^2+{\mathrm{QP}}^2-2\mathrm{NP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}};$ Wherein, M, N represent respectively the hanging point of wire jumper on strain insulator, and P is that wire jumper is installed skip before insulator string hanging point position, and Q then represents the jumping insulator string hanging point position after wire jumper is installed.

The beneficial effect of the embodiment of the invention is, strain tower of transmission line wire jumper installation method of the present invention can be measured wire jumper long accurately by carrying out crimping correction, sag correction and circuit corner correcting process, improved the efficient that wire jumper is installed.

Description of drawings

Fig. 1 is the strain tower of transmission line wire jumper installation method flow chart of the embodiment of the invention;

Fig. 2 is the adjustment sag schematic diagram of the embodiment of the invention;

Fig. 3 is wire and the drainage tube crimping figure of the embodiment of the invention;

Fig. 4 is that the nothing of the embodiment of the invention is jumped the wire jumper schematic diagram that string does not raise up;

Fig. 5 is that the nothing of the embodiment of the invention is jumped the wire jumper schematic diagram that string raises up;

Fig. 6 is the wire jumper schematic diagram of the single-hop string of the embodiment of the invention;

Fig. 7 is the wire jumper schematic diagram of the double jump string of the embodiment of the invention;

Fig. 8 is the wire jumper tie point spatial relationship figure of the embodiment of the invention;

Fig. 9 is that the total station survey of the embodiment of the invention calculates schematic diagram.

Embodiment

As shown in Figure 1, the invention provides a kind of strain tower of transmission line wire jumper installation method, it is characterized in that, the method comprises:

Step S301: the high angular difference of measuring wire jumper chord length l, wire jumper two hitch points

And wire jumper is adjusted sag f.

Wire catenary curve catenary equation formula under the uniform load model is the common-used formula that characterizes the wire mechanical characteristic.But in the engineering reality, under the condition that satisfies the computational accuracy requirement, can adopt easier approximate calculation method.The parabolic equation formula (5) of following catenary curve is approximate calculation method commonly used in the engineering calculation, in equation (5), satisfies between line length and the sag:

In the formula (5), L represents that wire jumper is long, and l is the air line distance of (or wire jumper drainage plate two center line intersection points are to jumper clamp hanging point) between wire jumper both sides drainage plate two center line intersection points, is called for short the wire jumper chord length,

Be the height difference angle between two hitch points, f is wire jumper (adjustment) sag.Conducting wire sag refers to from two hitch point lines along the load direction to the distance the wire axis.F as shown in Figure 2,201 represent cross-arm among Fig. 2,202 represent jumper clamp, 203 represent drainage tube.

Step S302: obtain conductor compression jointing length correction coefficient a and separation adjusted value b.

One of advantage of the present invention is to have introduced b and revises.For the quadripartion circuit, the sag that provides of design is generally two hitch points and is wired to distance between upper and lower wire mid point.If upper and lower sub-conductor is not adjusted, result of calculation can cause four root wire pitch to be slightly larger than standard sub-conductor spacing.Definition wire spacing adjusted value b, the size of b value is half of wire pitch value.Therefore, when calculating the line length of each sub-conductor, above two root wires need add an adjusted value b, make its lengthening, below two root wires need cut a b, it is shortened, thereby so that four root wire pitch are identical.

In addition, for the binary fission circuit, b is 0, and for six divisions and eight division circuits, the computational methods of b are similar to quadripartion, repeat no more.

Another advantage of the present invention is to have introduced a and revises.When wire and drainage tube crimping, conductor compression jointing length also is not equal to drainage tube length, and its error also can affect to sag, therefore, introduce crimping length correction factor a, a refers to the distance of the wire section of drainage tube center line intersection point after complete to crimping, as shown in Figure 3.

Step S303: with described l, Relational expression (1) between f and a substitution line length and the sag generates the long L of wire jumper.

The method of calculating wire jumper length increases by two adjusted value a and b exactly again on the basis of parabola sag (adjustment sag), chord length computing formula, the result is accurate to centimetre.

The high angular difference of wire jumper chord length l, wire jumper two hitch points

Wire jumper is adjusted sag f, conductor compression jointing length correction coefficient a and separation adjusted value b all needs by measuring.The workmen measures wire jumper chord length l, high angular difference at upper tower

The time, the unified upward hanging point of selecting in measurement point position uses the rigidity ruler, and ruler must be tightened, and reduces the measure error that ruler self gravitation and windage yaw cause.When measuring sag f, the operating personnel on the wire oneself center of gravity is positioned in the middle of the two horizontal sub-conductors, otherwise may affects the accuracy of measurement sag.

Step S304: according to the long L intercepting of wire jumper wire, carry out installing on the tower behind the described wire of crimping intercepting on the ground.

After obtaining the long L of wire jumper and carry out wire intercepting by step S303, can be that the two ends of the wire of L are crimped on drainage tube 203 on the ground with the length of intercepting.The intercepting of wire and crimping should be noted that following content:

When the wire intercepted length measures, need wire is lifted from ground, along the conductive line surfaces horizontal survey.After wire jumper length determines, can carry out at the wire jumper of not crimping picture seal (drawing crimping position), then be put into ground and carry out crimping.When ground crimping drainage connecting plate, wire jumper should be launched, do not make wire stressed, the drainage connecting plate at two ends will be in same plane.The wire two ends are placed on the ground of below, installation site after the ground crimping is finished, and place mat will be carried out with tarpaulin in ground, prevent the wire damage.

After the whole installations of drainage thread, the installation interval rod.The conductor spacer erection sequence is that two is installed first, in the middle of installing again.Forbid the workmen directly to climb installation interval rod on drainage thread.

Preferably, for so that the long L of wire jumper is more accurate, after step S303, it is also conceivable that the sag that difference is jumped under the string form carries out correcting process, can consider circuit corner is revised simultaneously.The below makes introductions all round:

1, three kinds of situations of strain tower wire jumper length gauge point counting: without jumping string, single-hop string and double jump string, the below is different sag correcting process of jumping under the string form respectively.

(1) without jumping string

Wire jumper is when jumping string, needs to measure the air line distance between the hanging point on the every wire jumper chord length l(both sides drainage plate), and the vertical range f of cross-arm lower plane hanging point line to the drainage plate of wire jumper both sides ₀, as shown in Figure 4, f ₁Expression design sag.

Because the wire jumper span is less, be subjected to the impact of wire self rigidity, the wire clamp Way out often not in the vertical plane that span becomes, cause wire jumper may produce about, bend right and left, be difficult to be the parabolic shape of rule.For guaranteeing wire jumper to gap value of meeting design requirement of discharge portion, when adopting relational expression (1) 1 to carry out the wire jumper length computation, need the adjusted design sag.

For the adjustment of sag, according to the statistics of field test: the sag error changes with the size of wire jumper chord length l.At f/l hour, actual measurement sag and design sag error are for negative, and the actual measurement sag is less than the design sag; Along with the increase of span, it is large that f/l becomes, and when f/l increased to certain value, the actual measurement sag just became with design sag error, and the actual measurement sag is greater than the design sag.Separation according to the statistics f/l of field test (the invention is not restricted to 0.23) about 0.23.Because the separation of f/l is subjected to various factors (length of strain hardware fitting, wire dangle angle, the corner number of degrees and the hitch point discrepancy in elevation etc.), is not a fixed value.Therefore, the correction of sag can only be adopted the asymptotic revised law of segmentation.

When f/l＜0.23, the sag correction value is calculated as follows

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\max }---\left(2\right)$

Wherein, f _MaxFor the wire jumper maximum is allowed the sag permissible value, its size adds wire jumper sag limits of error value for the design sag.

As f/l〉0.23 the time, sag adjustment value calculating formula is:

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\min }---\left(3\right)$

Wherein, f _MinFor the wire jumper minimum is allowed the sag permissible value, its size deducts wire jumper sag limits of error value for the design sag.

, the sag f in the relational expression (1) need to be revised according to formula (2) or formula (3) without jumping the string situation for strain tower.When f/l＜0.23, the sag in the relational expression between line length and the sag is revised according to formula (2).As f/l〉0.23 the time, the sag in the relational expression between line length and the sag is revised according to formula (3).

After the correction, correction value f* substitution relational expression (4) is obtained the long L of wire jumper, wherein, f _MaxFor the wire jumper maximum is allowed sag permissible value, f _MinFor the wire jumper minimum is allowed the sag permissible value.Relational expression (4) is as follows:

In relational expression (4), owing to need cut on the drainage plate of two ends hanging point to the distance of wire jumper termination, so correction value need to cut 2a without the situation of jumping string.

Without the tower that raises up, upper cross-arm and middle cross-arm are adjusted sag generally than about the smaller 0.1m of design sag owing to will consider simultaneously the safe distance of upper and lower surface discharge portion for strain insulator string, and lower cross-arm is adjusted sag and generally got the design sag.

When strain insulator string raises up, such as Fig. 5, satisfy the discharging gap distance value for guaranteeing the cross-arm edge, adjusting sag should suitably increase, and the sag after general the adjustment is larger than design load, and upper, middle and lower phase adjusted value becomes greatly successively, is shown in Table 1.

Table 1

(2) single-hop string

For strain tower single-hop string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁And l ₂(as shown in Figure 6), respectively with l ₁And l ₂Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the second wire jumper ₂, L=L ₁+ L ₂The situation that strain insulator raises up is with identical without the situation of jumping string, but the situation that sag adjustment value ratio nothing is jumped when going here and there is little, and the sag adjustment rate is generally about 5%～10%.

With identical when jumping string, when f/l＜0.23, the sag in the relational expression between line length and the sag is revised according to formula (2).As f/l〉0.23 the time, the sag in the relational expression between line length and the sag is revised according to formula (3).

(3) double jump string

For strain tower double jump string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁, l ₃And the double bounce string in the middle of hanging hole apart from l ₂, as shown in Figure 7.The value l of sag is adjusted on both sides ₁, l ₃With single-hop string, identical without jumping string situation, l ₂Corresponding middle sag does not need because two hanging points are contour to adjust.Respectively with l ₁And l ₃Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the 3rd wire jumper ₃, with l ₂Substitution relational expression (4) obtains the long L of the second wire jumper ₂, L=L ₁+ L ₂+ L ₃

With identical when jumping string, when f/l＜0.23, the sag in the relational expression between line length and the sag is revised according to formula (2).As f/l〉0.23 the time, the sag in the relational expression between line length and the sag is revised according to formula (3).

When 2, circuit corner being revised, in strain tower single-hop string situation,

${\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HDA00002442908400041.png"\; state="\{\{state\}\}">l</figure-callout>}}_1=\mathrm{MQ}=\sqrt{{\mathrm{MP}}^2+{\mathrm{QP}}^2-2\mathrm{MP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}}---\left(6\right)$

$l_2=\mathrm{NQ}=\sqrt{{\mathrm{NP}}^2+{\mathrm{QP}}^2-2\mathrm{NP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}}---\left(7\right)$

Wherein, M, N represent respectively the hanging point of wire jumper on strain insulator, and P is that wire jumper is installed skip before insulator string hanging point position, and Q then represents the jumping insulator string hanging point position after wire jumper is installed.The calculating of above-mentioned formula (6), (7) is described in detail as follows:

Because wire jumper is space curve, when wire jumper was nothing jumping string, no matter how two hitch point locus changed, and wire jumper and two hitch points are in the same plane all the time, and circuit corner can not impact the wire jumper precision.And for the situation of single-hop string and double jump string, the circuit corner meeting causes the variation of hanging point locus so that wire jumper departs from the vertical plane that span becomes, thereby causes the measure error of hanging point chord length.Fig. 8 concerns schematic diagram for considering the wire jumper tie point spatial position change behind the circuit corner, the G point is the cross-arm hitch point, M, N represent respectively the hanging point of wire jumper on strain insulator, and P is that wire jumper is installed skip before insulator string hanging point position, and Q then represents the jumping insulator string hanging point position after wire jumper is installed.

Because there were angle α in plane GMP and GMQ before and after wire jumper was installed between GNP and GNQ, were not positioned at same plane, the actual hanging point chord length after having caused the hanging point chord length measured and having installed is also inconsistent, i.e. MP ≠ MQ, NP ≠ NQ, and deviation has occured in length l.

There are following relationship in MP and MQ by calculating as can be known:

$\mathrm{MQ}=\sqrt{{\mathrm{MP}}^2+{\mathrm{QP}}^2-2\mathrm{MP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}}---\left(6\right)$

$\mathrm{NQ}=\sqrt{{\mathrm{NP}}^2+{\mathrm{QP}}^2-2\mathrm{NP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}}---\left(7\right)$

MP, NP are that hanging point arrives the distance of jumping string upper conductor hanging hole on the drainage plate that measures before wire jumper is installed in the formula.QP, ∠ MPN are calculated as follows:

$\mathrm{QP}=d\sqrt{2(1-\cos \mathrm{\&alpha;})}---\left(8\right)$

$\&angle;\mathrm{MPN}=\arccos \frac{{\mathrm{MP}}^2+{\mathrm{NP}}^2-{\mathrm{MN}}^2}{2\mathrm{MP}\&CenterDot;\mathrm{NP}}---\left(9\right)$

Wherein, d is for jumping insulator string length, and MN is the distance between hanging point on the drainage plate two.In the situation that consider the circuit corner impact, what wire jumper chord length l answered substitution in the line length computing formula is the value of MQ, NQ, rather than MP, NP.Use by a plurality of engineerings, during in drift angle α＜5 °, circuit corner is very little on the impact of wire jumper precision, generally can ignore.

When above-mentioned sag correcting process and circuit corner correction, and obtain after the revised wire jumper length, the data measuring method that needs is as follows:

The instrument that the aerological measurement data need to be prepared has rope ladder and steel tape (error is little).Upper tower measurement size, the unified large size side that is placed on circuit zero point with steel ruler, the measuring position will be placed on the hanging point center.For without the direct measuring distance l of the situation of jumping string, the vertical range f of cross-arm lower plane hanging point line to the drainage plate of wire jumper both sides ₀The available rope of measurement the upper hanging point of two drainage plates is linked to each other, put a level gauge in the cross-arm midpoint, measure the vertical range of level gauge and upper left sub-conductor two hanging point lines.The situation of single-hop string is for the operation that makes things convenient for operating personnel on the tower can be measured first l ₁And l ₁+ l ₂, calculate again l ₂The situation of double jump string measures first l ₁, l ₁+ l ₂And l ₁+ l ₂+ l ₃, calculate again l ₂And l ₃, measure form and see appendix.It should be noted that especially wire size will determine accurately, top two chord length measured value is more or less the same in the general four root wires, below two be more or less the same, can determine tentatively whether measured value accurate with this principle during measurement.

After calculating wire jumper secant line length, for avoiding measuring the error that causes, wire measures method and needs standard: answer left hand that steel tape is pressed on the wire, right hand thumb is on tape measure, forefinger is under tape measure, smoothing out with the fingers tape measure and be close to wire and measure forward, measure simultaneously all need have before and after the taker people with tape measure and wire by being in the same place.

Wire jumper measures complete rear picture seal, and then secant can draw seal with the installation site of conductor spacer at 1 work song wire according to designing requirement on the spot.Drainage plate crimping complete rear upper tower in wire jumper two ends is installed wire jumper, uses men hoisting coaster (Φ 15 nylon ropes) to carry out the wire lifting.Install in the whole process at wire jumper, use rope ladder as workmen's bearing tool, the lower end is caught hold of with marline and is regulated and the distance of jumping string and drainage thread.By the picture seal position installation interval rod of conductor spacer on the 1 work song wire, and make it perpendicular to its excess-three root wire, can greatly shorten the engineering time like this.

The below expands strain tower wire jumper assembled manufacture craft:

Chord length between wire jumper two hanging points, the discrepancy in elevation generally all are to be measured by the upper tower of work high above the ground personnel, and efficient is relatively low.If utilize total powerstation to measure the distance of point-to-point transmission on the tower, then can save work high above the ground, both guaranteed fail safe, also improved operating efficiency, measuring principle is as shown in Figure 9.Suppose that distance A D needs 2 distances measuring on the tower, total powerstation is positioned at an O, the point B, C be respectively an A, the D upright projection on horizontal plane, utilize total powerstation measure elevation angle ∠ AOB, ∠ DOC, horizontal angle ∠ BOC and total powerstation and measured point apart from OA, OD.By spatial relationship shown in Figure 9, cross a some A and make AE ∥ BC and hand over DC in an E, AE ﹦ BC then, AE ⊥ DC, some A and the discrepancy in elevation DE of some D can survey.The length of AD can calculate by following formula.

$\mathrm{AD}=\sqrt{{\mathrm{AE}}^2+{\mathrm{DE}}^2}---\left(10\right)$

$\mathrm{AE}=\sqrt{{\mathrm{OB}}^2+{\mathrm{OC}}^2-2\mathrm{OB}\&CenterDot;\mathrm{OC}\&CenterDot;\cos \&angle;\mathrm{BOC}}---\left(11\right)$

Wherein, OB=OAcos ∠ AOB, OC=ODcos ∠ DOC.

The beneficial effect of the embodiment of the invention is, strain tower of transmission line wire jumper installation method of the present invention can be measured wire jumper long accurately by carrying out crimping correction, sag correction and circuit corner correcting process, improved the efficient that wire jumper is installed.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; the protection range that is not intended to limit the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (7)

1. a strain tower of transmission line wire jumper installation method is characterized in that, described method comprises:

Step 1: the high angular difference of measuring wire jumper chord length l, wire jumper two hitch points

And wire jumper is adjusted sag f;

Step 2: obtain conductor compression jointing length correction coefficient a and separation adjusted value b;

Step 3: with described l,

Relational expression (1) between f and a substitution line length and the sag generates the long L of wire jumper,

$L=l+\frac{{8f}^2}{3l}\stackrel{2}{\cos \mathrm{\&phi;}}-a\&PlusMinus;b---\left(1\right);$

Step 4: according to the long L intercepting of wire jumper wire, carry out installing on the tower behind the described wire of crimping intercepting on the ground.

2. method according to claim 1 is characterized in that, without jumping the string situation, after step 3, described method also comprises for strain tower: the sag in the relational expression (1) is revised according to following formula (2) or formula (3),

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\max }---\left(2\right)$

$f*=\frac{f}{l}f+(1-\frac{f}{l})f_{\min }---\left(3\right)$

Then correction value f* substitution relational expression (4) is obtained the long L of wire jumper, wherein, f _MaxFor the wire jumper maximum is allowed sag permissible value, f _MinFor the wire jumper minimum is allowed the sag permissible value;

3. method according to claim 2 is characterized in that, for strain tower single-hop string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁And l ₂, respectively with l ₁And l ₂Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the second wire jumper ₂, L=L ₁+ L ₂

4. method according to claim 2 is characterized in that, for strain tower double jump string situation, measure hanging point on the drainage plate to jump string upper conductor hanging hole apart from l ₁, l ₃And the double bounce string in the middle of hanging hole apart from l ₂, respectively with l ₁And l ₃Substitution formula (2) or formula (3) are revised, and obtain respectively the long L of the first wire jumper ₁And the long L of the 3rd wire jumper ₃, with l ₂Relational expression below the substitution (4) obtains the long L of the second wire jumper ₂, L=L ₁+ L ₂+ L ₃

5. according to claim 2,3 or 4 described methods, it is characterized in that, when f/l＜0.23, the sag in the relational expression between line length and the sag is revised according to formula (2).

6. according to claim 2,3 or 4 described methods, it is characterized in that, as f/l〉0.23 the time, the sag in the relational expression between line length and the sag is revised according to formula (3).

7. method according to claim 3 is characterized in that, for strain tower single-hop string situation, $l_1=\mathrm{MQ}=\sqrt{{\mathrm{MP}}^2+{\mathrm{QP}}^2-2\mathrm{MP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}},$ $l_2=\mathrm{NQ}=\sqrt{{\mathrm{NP}}^2+{\mathrm{QP}}^2-2\mathrm{NP}\&CenterDot;\mathrm{QP}\&CenterDot;\cos \frac{\&angle;\mathrm{MPN}}{2}};$ Wherein, M, N represent respectively the hanging point of wire jumper on strain insulator, and P is that wire jumper is installed skip before insulator string hanging point position, and Q then represents the jumping insulator string hanging point position after wire jumper is installed.

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