Pay attention to the conductor materials of the busbar: Currently, there are three types of conductor materials: copper rod, aluminum rod, and copper aluminum composite material, with significant price differences. In addition to purity, attention should also be paid to the mechanical properties of the material after bending. The interface strength of copper aluminum composite materials directly affects their processing performance and reliability. It is a key performance parameter of copper aluminum composite busbar. Only when there is no blistering, obvious orange peel, copper or aluminum delamination during the punching and shearing processes, and the low requirements for interface bonding strength are met, can it be used for electrical equipment.
1. Different manufacturing processes have different interface bonding strengths. When copper and aluminum are pressed together by mechanical pressure, only interface atoms can be activated to form atomic bonds. After heat treatment, the point connection becomes a surface connection, but the diffusion depth is very thin and the interface connection strength is not high. Only by fusing copper and aluminum under specific process conditions can the interface be uniformly bonded with a certain thickness of the composite layer, achieving high interfacial bonding strength. After extensive experiments and computer finite element analysis, it has been found that when the copper cross-section accounts for 20% of the total cross-section, the cost-effectiveness is good. Due to the skin effect, the conductivity is significantly increased by 20%, the hardness is increased, and the service life is extended. There is a certain relationship between the cross-sectional ratio of copper layer and the specific gravity of copper aluminum composite busbar. When the cross-sectional area of copper accounts for 10%, 15%, and 20% of the total cross-sectional area, this proportion will increase by 32%, 3.63, and 3.94 (g/cm3), respectively. The simple method for detecting the cross-section of a copper layer is to find a sample, weigh it, calculate the volume of the sample, and calculate the specific gravity.
2. Use qualified products from legitimate enterprises: Use 3C mandatory certification mark products for bus lanes, and provide type test reports. During procurement, a thorough investigation should be conducted into the production scale, technical strength, worker quality, and production environment of the production enterprise, especially the production environment. Because if unclean spaces are insulated, there will be some conductive particles in the insulation layer. It doesn't matter at the beginning of operation, but long-term operation can damage the insulation layer. The economic cross-section of the waterproof busbar duct should be selected based on the large long-term working current. The short-term thermal stability and dynamic stability of waterproof bus ducts should be verified based on the conditions of large short-circuit cables. When the wires are close to each other, due to the influence of wire resistance and AC ammeter effect, the waterproof bus duct will generate heat when passing through the current. The long-term allowable heating temperature for bare copper and aluminum busbars is 70 ° C. However, when the contact surface is reliably covered with tin (such as ultrasonic tin plating), due to the allowable temperature limit of continuous heating, the temperature is allowed to rise to 85 ° C. For waterproof bus ducts of different materials and cross sections, corresponding long-term allowable current values are given. When selecting waterproof bus duct components, ensure that the actual maximum value of the waterproof bus duct is less than the long-term allowable current value of the selected component's waterproof bus duct.
3. The manufacturer of waterproof bus ducts suggests that when the average load of the year is large and the waterproof bus duct is long (such as the waterproof bus duct of outdoor distribution equipment), the economic current density method should be used. Economic current density refers to the small current passing through the unit cross-sectional area of the busbar, taking into account the losses of the busbar, annual maintenance costs, and depreciation costs of the busbar and auxiliary equipment. Divide the economic current density by the long-term operating current (excluding overload) to obtain the cross-sectional area of the busbar.