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The use of insulated conductors in rural power grid reconstruction can increase the level of safety in rural power grids, reduce power outages in rural power grids, and reduce the number of electric shocks and casualties among rural customers. This has significant operational benefits. Especially when crossing forests, densely populated areas and houses and other facilities, the workload of operation and maintenance can be significantly reduced, the daily operation and maintenance costs can be reduced, and the controllable, controllable and control factors of safe production can be improved.
However, rural power grids have their own unique operating characteristics, such as a large number of customers and scattered, long power supply lines, limited maintenance funds, etc. When using insulated conductors in transformation, it is necessary to pay attention to the following matters while continuing to reform standards and management requirements. . In this way, the operational benefits of insulated conductors can be significantly increased.
1 wire diameter selection problem
Because the rural power grid has long power lines, many power supply facilities, and limited maintenance funds, it is determined that limited maintenance funds cannot implement large-scale transformation of rural power grids. Therefore, in the implementation of the rural network transformation, under the condition of adequate funding, it is necessary to improve the standards of construction and reconstruction as much as possible, and in accordance with the principle of “changing one and becoming one”, guaranteeing the insulation lines, towers, and all kinds of fittings and accessories erected. Can meet the needs of the distribution transformer's final capacity increased to 400 kVA. In this way, when the capacity expansion and transformation are carried out later, the troubles of reconstructing the line can be saved, and the investment efficiency can be improved. For 400 kVA distribution transformers, in accordance with the consideration of two return lines for low voltage, the diameter of insulated conductors for each return line should be at least 120 mm2 and above (aluminum core), preferably 150 mm2.
2 Continuing item selection problem
All kinds of continuation parts (gold fittings, accessories) used for insulated conductors must be dedicated (it is not recommended to use puncture clips), and non-specialized continuation parts cannot be used simply to reduce the project cost during the renovation. During the renovation project construction, we must adhere to the principle of using special continuation parts for material procurement and construction; in the daily use after completion of the project, for the newly added leads (including newly installed customers and various types of temporary electricity use) Material reserves must be used in accordance with the principle of using special continuants. In this way, the safe life of insulated conductors can be guaranteed.
3 step control problem
In order to build a harmonious new countryside, the power supply company is obliged to tap some of the drop-in lines, install some 2 meter and 4 meter meter boxes, reduce the length of the customer's incoming line, and standardize the installation process of the customer's access line. Fundamentally increase the level of rural safe electricity use. For this reason, when the 0.4 kV rural power supply line is reformed, it must be arranged and installed as many as possible. At the same time, taking into account the larger weight of the insulated wire and its fittings and accessories, scientifically and reasonably controlling the span can effectively solve the above problems. In principle, the spacing of insulated conductors should be controlled within 40 m. It is better to combine the distribution of rural customers (houses). Considering that it is conducive to the installation of house lines and the reduction of customer access lines, a more scientific and reasonable setting is required. distance.
4 Downline distribution box pre-installation problem
Due to new customers, new T-connected lines and other reasons, during the operation of overhead insulated lines, there may be a need to scratch the insulation skin to connect new customers and new lines. If the power supply station (operational maintenance unit) that undertakes the work at this time does not have special continuation parts for which insulated conductors are stored in advance, it may leave hidden safety hazards when handling the insulating skin, and it will occur during the subsequent operation. The danger of disconnection. To this end, when the project is designed, it is necessary to consciously consider the possibility of new line connections that may arise in the future. A certain number of distribution boxes are pre-installed in suitable locations in advance to avoid potential safety hazards in subsequent connection work.
5 Reserve problem of grounding electroscope
In the course of construction, overhead insulated conductors are usually installed on the terminal rods and the tensile rods to be electrically grounded to prepare for inspection and installation of grounding wires during line inspections. However, in the actual operation, when most of the insulated conductors undergo maintenance and repair tasks, they will feel that the grounding inspection device is installed too little, and sometimes the insulation skin must be re-scratched to perform the inspection and installation at specified points. line. In this way, there will be many hidden dangers in the safe operation of insulated wires in the future. For this reason, in the process of construction of overhead insulated conductors, installation of grounding electro-optical devices on the corner bars and branch poles will be facilitated for subsequent maintenance and repair work.