The grounding treatment of the power distribution cabinet is essential to ensure the safety of electricity use. The following are some key methods and precautions for achieving effective grounding of the power distribution cabinet.
First, choosing a suitable grounding system is the basis. Common grounding systems include TN, TT and IT systems, which should be selected according to the specific power environment and requirements. For example, in urban buildings, the TN system is generally widely used because it can provide better fault protection.
The material and specifications of the grounding conductor must meet the standards. Copper or galvanized steel is generally used as the grounding conductor, and its cross-sectional area should be determined according to the expected fault current and grounding resistance requirements. If the cross-sectional area is too small, when a fault current occurs, the grounding conductor may not be able to withstand the large current and fuse, resulting in grounding failure.
Ensure reliable connection between the power distribution cabinet and the grounding grid. The grounding grid should be buried at a certain depth underground, and the grounding resistance should meet the specified value. The power distribution cabinet is connected to the grounding grid through a grounding busbar or grounding wire, and the connection should be tightened to prevent loosening and corrosion. Welding, bolting, etc. can be used, and anti-rust and anti-corrosion treatment should be done.
The equipment and metal parts inside the power distribution cabinet should also be fully grounded. For example, the cabinet body, cabinet door, and metal casing of electrical components should all be grounded. This can prevent people from getting electric shock when the equipment leaks electricity.
Regularly testing the grounding resistance is an essential step. Use a professional grounding resistance tester to test according to the prescribed cycle. If the grounding resistance exceeds the allowable value, timely measures should be taken, such as increasing the number of grounding electrodes and improving the laying method of the grounding grid, to reduce the grounding resistance.
During the construction and installation process, the relevant electrical installation specifications must be strictly followed. Avoid problems such as too small bending radius of the grounding wire and too long grounding line leading to increased resistance.
In addition, care should be taken to prevent the grounding system from being interfered with by external factors. For example, strong electromagnetic fields and chemical corrosive substances nearby may affect the performance of the grounding system.
In order to improve the reliability of grounding, multiple grounding methods can be used. That is, multiple grounding connection points are set at different locations to ensure that effective grounding can be maintained when a problem occurs at a certain connection point.
At the same time, the grounding system of the power distribution cabinet should be well marked and recorded. Clarify the location of the grounding connection point, the detection value of the grounding resistance and other information to facilitate subsequent maintenance and management.
In short, by rationally selecting the grounding system, correctly selecting the grounding conductor, ensuring reliable connection, regular inspection and maintenance, etc., effective grounding of the power distribution cabinet can be achieved, ensuring the safety of electricity use to the greatest extent and preventing electrical accidents.
