Tightening method of bare wire for electric power
1. High-altitude tight line hair and high-altitude drawing and printing tight line method
The high-altitude tightening method is mainly used in the tightening construction of distribution lines with small conductor cross-sectional area and low tightening tension. It has the advantages of simple construction method, small operation site and less construction equipment. However, most of the processes must be completed at high altitudes, which increases the workload of high-altitude operations. When tightening the line, the remaining line should be tightened first. Usually, it is directly operated on the ground by manpower or traction equipment. When the overhead line in front is off the ground, you can put a tensioner at a certain distance (estimated length of the tensioning line) in front of the tension operating pole tower, use the traction equipment to pull the tensioning wire rope, and tighten the wire through the pulley at the hanging line. When the overhead line is tightened near the sag requirement, slow down the pulling speed. When the sag observer in front is notified that the required sag value has been reached, the towing is stopped immediately. When the overhead line stops beating and there is no change in the sag, it can be marked on the operating pole tower according to the hole of the hanging line. After marking, the construction personnel on the tower will install tension clamps on the guide and ground wires at high altitude, and hang the guide and ground wires on the tower. This method of operation is called the one-time tightening method because the overhead line does not need to be grounded by Panasonic. If the guide and ground wires are loosened and landed after marking at a high altitude, the ground operator will install the tension clamp according to the mark, and at the same time assemble the insulator string, tighten the wire again, and hang the wire. This method is called the secondary lifting and tightening method. . The advantage is that it reduces the amount of work at heights. It is suitable for lines with large wire cross-section and tight wire tension, especially for crimping type tension clamps, which are quite inconvenient for high-altitude construction, so most of them use this method.
2. The method of marking and printing on the ground
It is referred to as the ground marking method, which is to hang the overhead line on the tightening line operating pole tower close to the ground for sag observation. Since the overhead line is close to the ground for easy control, it can avoid the situation of high altitude marking and loosening in the case of complex terrain. The line is too far, resulting in the difficulty of secant crimping, and the construction is simpler and safer than the high-altitude marking method. Although the calculation workload is large using this method, since the electronic computer was put into use, the calculation conditions have been improved, so the use of this method is also increasing.
3. Low arc sag tight line method
When the tension section is not too long, the construction method of low arc sag tight line can often be adopted to avoid repeated adjustment in order to obtain the required arc sag value. The low-arc sag tightening wire is used, and the wire tension is small, which can simplify the tightening operation process and speed up the tightening speed. The method is to tighten the overhead line with the slack tension, and measure the sag of the overhead line at this time, which is larger than the required standard sag. , the sag of the overhead line meets the design requirements.
4. Multi-gear connection method
It is a method of taking the tightening work of several consecutive tension sections as one tension section. When tightening the wire, a comprehensive representative span of all the tightening wire stops can be used for sag observation, or the representative span of the last tension section close to the fixed end of the tightening wire can be used for sag observation. In this way, observing the sag according to a selected representative span to determine the line length of each tensile section will cause the line length in each tensile section to be inconsistent with the design requirements, so the line length is measured in each tensile section. When installing the length, it is necessary to adjust the line length error caused by the difference between the representative span of each tensile section and the selected representative span.
5. Assembly tight line method
It will omit the operation steps such as marking the tightening line on the tower when the line is tightened, and sag observation, and only need to hang the line. This is a method to improve construction efficiency and labor-saving. However, before wiring, it is necessary to perform precise measurement of the span according to the calculation of the required guide and the real length of the ground wire, the measuring ruler of the guide and ground wire, and the span.
6. Tension pay-off and tightening
It adopts the method of tightening the wire on the tower. Only the individual pay-off sections are divided into tension sections, and the tension line is tightened in the tension tower. The tension tower tension line is much more complicated than the linear tower tension line, so it is only used when the linear tower cannot be tightened.