A kind of method for vertical grounding down leading on inner side of composite material tower and shaft tower thereof
Technical field
The present invention relates to a kind of method for vertical grounding down leading on inner side of composite material tower and shaft tower thereof, belong to technology of transmission of electricity application in the electric power system.
Background technology
Shaft tower is the visual plant of transmission line, and the characteristic of its materials used directly has influence on fail safe, economy and the reliability of circuit operation.Because steel have the strength-weight ratio height, easily process and advantage such as installation, adopt all steel material shaft tower both at home and abroad at present mostly.But also there are defectives such as quality big (steel density is higher), easy-to-rust in all steel shaft tower, so need drop into bigger man power and material in shaft tower construction transportation and aspect safeguarding.And along with the development of composite material production technology and manufacturing process thereof, characteristics such as that composite material has is in light weight, intensity is big, corrosion-resistant, high-low temperature resistant, excellent in durability and insulating properties are strong, make composite material pole tower have cost of transportation low (particularly in meagrely-populated mountain area), antifouling, advantage such as antiseptic property is good, good application prospects is arranged.Adopted composite material pole tower in a large number in Canada, U.S. some areas at present.When but Canada, the U.S. use composite material pole tower, do not consider the problem of lightning protection.Its main cause is that its circuit institute that adopts composite material pole tower is area with less lightning activities (owing to Canada, U.S. some areas are in winter throughout the year, these regional thunderstorm days are very little) through the area.In addition, it is the following electric pressure of 110kV mostly that Canada, the U.S. use the circuit of composite material pole tower, and these electric pressure systems are central point isolated neutral systems, and electric pressure is low, and lightning fault is little to the impact of system.
China's overhead line structures mainly adopt reinforcing bar to coagulate materials such as earth, timber, steel (110kv and above electric pressure circuit adopt full shaft tower just usually) at present, because composite material pole tower has comparatively outstanding advantage, composite material pole tower (mostly in 110kV and above electric pressure) is also prepared in a lot of areas to use by China.Because these areas exist: problems such as the input in circuit corridor are big, lightening activity is intensive, filth is serious, so China is when using composite material pole tower, its main purpose is to reduce transmit electricity width of corridor, lightning protection (referring to reduce the lightning fault rate) and antifouling (referring to reduce power frequency pollution flashover failure rate by increasing the pollution flashover creepage distance) etc.
Composite material pole tower is faced with the problem of lightning protection just, so need construction of line lightning conducter (because problem Canadian, the U.S. does not consider lightning protection when adopting composite material pole tower, thereby do not set up lightning conducter), and the thunder and lightning energy when discharging thunderbolt lightning conducter (also claim " ground wire ") or cat head, to improve the counterattack lightning withstand level of circuit, reduce the lightning fault rate of circuit, need composite material pole tower to pursue tower ground connection.
Therefore, the application of transmission line composite material pole tower exists the problem of ground connection under drawing, and (all steel shaft tower is because body of the tower is a metallic conductor, ground wire is just directly received the earth by body of the tower naturally, so do not have again the problem of ground connection under drawing), under drawing, its ground connection has multiple diverse ways, grounding down-leading method will directly have influence on the lightning protection effect of composite material pole tower, but also have influence on the antifouling of circuit and reduce the width of corridor etc. of transmitting electricity, so being it, the grounding down-leading method of composite material pole tower needs the key technology and the difficult point that at first solve in using.
Summary of the invention
In order to address the above problem, the invention provides a kind of method for vertical grounding down leading on inner side of composite material tower and shaft tower thereof, this invention can be given full play to the insulating effect of composite material pole tower body of the tower, makes composite material pole tower embody its value and advantage at aspects such as antifouling, lightning protection and burn-out proof composite insulators.
Technical scheme of the present invention is: a kind of method for vertical grounding down leading on inner side of composite material tower, it is characterized in that: the ground wire cross-arm of head of mast adopts metal material, draw at the center of ground wire cross-arm one section certain-length along metal cross arm on the down conductor of lead direction, the end of metal cross arm vertically draws down conductor down on down conductor, this down conductor certain distance below following phase conductor is connected on the shaft tower by metal cross arm under the down conductor, last down conductor is along body of the tower ground connection, or when the body of the tower lower part was steel pipe, down conductor can directly be connected in ground connection on the steel pipe by metal cross arm under the down conductor.
Aforesaid a kind of method for vertical grounding down leading on inner side of composite material tower, it is characterized in that: draw symmetrically at the center of ground wire cross-arm two sections certain-lengths along metal cross arm on the down conductor of lead direction, vertically draw simultaneously following two down conductors symmetrically.
Aforesaid a kind of method for vertical grounding down leading on inner side of composite material tower is characterized in that: support with insulating bar between down conductor and composite material pole tower, guarantee not flexural deformation of down conductor.
A kind of composite material pole tower of ground connection, it is characterized in that: the ground wire cross-arm of head of mast adopts metal material, draw at the center of ground wire cross-arm one section certain-length along metal cross arm on the down conductor of lead direction, the end of metal cross arm vertically draws down conductor down on down conductor, this down conductor certain distance below following phase conductor is connected on the shaft tower by metal cross arm under the down conductor, last down conductor is along body of the tower ground connection, or when the body of the tower lower part was steel pipe, down conductor can directly be connected in ground connection on the steel pipe by metal cross arm under the down conductor.
The composite material pole tower of aforesaid ground connection is characterized in that: draw symmetrically at the center of ground wire cross-arm two sections certain-lengths along metal cross arm on the down conductor of lead direction, vertically draw simultaneously following two down conductors symmetrically.
The composite material pole tower of aforesaid ground connection is characterized in that: support with insulating bar between down conductor and composite material pole tower.
The invention has the beneficial effects as follows:
(1) avoids down conductor short circuit composite material pole tower body of the tower, brought into play the insulating effect of composite material body of the tower, made lead creepage distance over the ground strengthen, strengthened the ability of its pollution flashover of anti-the power frequency;
(2) avoided the adverse effect of cross-arm gold utensil to the lightning impulse dielectric strength, guaranteed that thunder and lightning lead minimum air void distance is over the ground decided by the minimum range of lead to down conductor, thereby strengthened lead insulation distance over the ground, strengthened its anti-lightning impulse dielectric strength;
(3) avoided the burn problem of the power frequency continued flow behind the lightning flash over to composite insulator;
When (4) having avoided down conductor to move on the ground, to the inconvenience influence of life;
(5) features simple structure is easy to realize.
Description of drawings
Fig. 1 is the front view of the monolateral down conductor of the embodiment of the invention.
Embodiment
Description of symbols among Fig. 1: 1-ground wire cross-arm, metal cross arm on the 2-down conductor, 3-down conductor, metal cross arm under the 4-down conductor, 5-supports insulative bar, 6-composite insulator, 7-cross-arm gold utensil, the body of the tower part of 8-tower head, the 9-ground wire, the last phase conductor of 10-, phase conductor among the 11-, phase conductor under the 12-, 13-body of the tower lower part.
Ground wire cross-arm 1 among the present invention adopts metal material, draws one section certain-length D at the center of ground wire cross-arm 1
1Along metal cross arm 2 on the down conductor of lead direction, the end of metal cross arm 2 vertically draws down down conductor 3 on this down conductor, this down conductor 3 is certain distance D below phase conductor 12 down
2Be connected on the shaft tower by metal cross arm 4 under another down conductor.Increase on this down conductor metal cross arm 4 under the metal cross arm 2 and down conductor, can be grounded between the body of the tower part 8 of downlead 3 and tower head and separated certain distance D
1, its objective is and avoided down conductor 3 short circuit bodies of the tower, brought into play the insulating effect of composite material pole tower body of the tower, make lead power frequency pollution flashover flashover path over the ground increase, thereby strengthened the ability of its pollution flashover of anti-the power frequency; In addition, in distance D
1When enough big, the impulse flashover path is without cross-arm (the impulse flashover path is the minimum air void distance of down conductor to lead), thereby (adverse effect is meant when down conductor is close to the shaft tower outer wall also to have avoided the adverse effect of 7 pairs of lightning impulse dielectric strengths of cross-arm gold utensil, because the existence of cross-arm gold utensil 7, make lead to the minimum air void of down conductor 3 distance less than lead to the minimum air void of down conductor 3 apart from shortening, wherein lead to the minimum air void of down conductor 3 apart from having determined lead lightning impulse dielectric strength over the ground), strengthened the anti-lightning impulse dielectric strength of composite material pole tower; And because the burn problem of the power frequency continued flow behind the lightning flash over to composite insulator without cross-arm, also avoided in the impulse flashover path.
On the down conductor under metal cross arm 2 and the down conductor metal cross arm 4 also played the effect of the down conductor 3 under stay bolt vertically draws, make down conductor 3 under the effect of strong wind iso-stress, bigger flexural deformation can not take place, down conductor 3 should adopt higher, the on-deformable electric conductor of intensity, if in order further to guarantee down conductor 3 not flexural deformations, can add supports insulative bar 5 down conductor 3 and composite material pole tower support are come, as shown in fig. 1.
Also can draw the metal cross arm along the lead direction of two sections certain-lengths at the center of ground wire cross-arm 1 symmetrically, two down conductors under vertically drawing symmetrically can strengthen the shunting action of down conductor like this.
Down conductor 3 under vertically drawing is connected under the down conductor after the metal cross arm 4, down conductor 3 inserts the earth along body of the tower, if being tower head, composite material pole tower uses composite material and the remaining part steel pipe, as long as metal cross arm 4 is the steel pipes that are fixed on remaining part under the down conductor, just can directly insert the earth by the steel pipe body of the tower, thereby when having avoided down conductor 3 directly vertically to move on the ground, to the inconvenience influence of life.
Generally speaking, this composite material pole tower grounding down-leading formula structure intuitively, simply clear, be easy to realize.