Method statement for maintenance of low voltage switchgear
The complete set of low-voltage switchgear and control equipment is commonly known as low-voltage switchgear, also known as low-voltage distribution cabinet. It refers to the complete set of electrical devices with AC and DC voltage below 1000V.
China's low-voltage distribution cabinet market has maintained a rapid growth trend in recent years with the construction and implementation of smart grid, infrastructure, investment in manufacturing and the development of new energy industry.
The maintenance of low-voltage distribution cabinet is mainly to ensure the normal and safe operation of low-voltage distribution cabinet. The general physical examination and maintenance of low-voltage distribution cabinet shall be carried out every year. The maintenance shall be completed with the minimum outage time, and the outage time of the owner shall be determined one day in advance.
Maintenance contents and steps of low voltage distribution cabinet:
1: The maintenance shall start from the low voltage side of the transformer. After power failure of the distribution cabinet, clean the dust in the cabinet, check whether the bus and down lead are well connected, whether the joint points are heated and discolored, whether the cable head and wiring pile head are firm and reliable, whether the grounding wire is rusted and whether the wiring pile head is fastened. All secondary circuits shall be connected reliably and the insulation shall meet the requirements.
2: When checking the drawer switch, the drawer switch cabinet shall be flexible when pushed in or pulled out, and the mechanical locking shall be reliable. Check whether the automatic air switch operating mechanism on the drawer cabinet is in place and whether the wiring screws are fastened. Remove the dirt on and around the contact surface of the contactor, and check whether the contact of the contactor is intact. If the contact is poor, slightly file the contact surface if necessary. If the contact is seriously ablated (the contact point is worn to 1 / 3 of the original thickness), replace the contact. The power indicating instrument and indicator light are intact.
3: When repairing the capacitor cabinet, disconnect the main switch of the capacitor cabinet first, discharge the capacitors to the ground one by one with a wire of more than 10mm2, and then check the appearance of the shell to ensure that there is no oil leakage. If the capacitor shell expands, deal with it in time, and replace the discharge device, the wiring screw of the control circuit and the grounding device. Commissioning of indication part and automatic compensation part after closing.
4: Maintenance of circuit breaker in power receiving cabinet and liaison cabinet: disconnect all loads first, and then shake out the circuit breaker with a handle. Retighten the wiring screw and check whether the elasticity of the knife edge meets the requirements. Check whether the arc extinguishing grid is broken or damaged, manually debug whether the opening and closing of mechanical interlocking is accurate, check whether the contact contact is good, file the contact surface if necessary, and check whether the internal spring, gasket and screw are loose, deformed and falling off.
Under the favorable environment of China's low-voltage distribution cabinet market demand, the internal competition in the industry will intensify. Suppliers providing a new generation of low-voltage complete sets of equipment and system solutions will take the lead in the future market competition. Only with the above characteristics can enterprise products win certain advantages in the future competition, so as to seize the commanding height of the fourth generation of low-voltage electrical products.