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How to improve the short-circuit resistance of distribution transformers

Author:ZTELEC   Update time:2018-08-16 15:44:47
Short-circuit faults include three-phase shorts, two-phase shorts, two-phase grounding, and relative ground faults, especially at the exit (head end). The electric power generated by the huge overcurrent is increased by several hundred times because it is proportional to the square of the current, which is extremely harmful to the power transformer. Therefore, it is necessary to effectively suppress the short circuit fault and improve the short circuit resistance.
In order to effectively improve the short-circuit resistance of distribution transformers, ZTELEC has developed a practical and feasible way by integrating the methods of other transformer manufacturers.
◆The introduction of international advanced technology fully considers the various conditions of the product under short-circuit and solves the problem. It adopts a series of measures such as six-face rigid positioning of the body to maintain the overall stability of the product.
◆Design uses dynamic force calculation to evaluate the dynamic thermal stability of the product; set up a separate voltage regulating coil to strictly ensure the balance of the high and low coils, while maintaining the same high and low magnetic cores of the voltage regulating coil, so that the short-circuit electric power is minimized. ;
distribution transformers,power transformer
◆The low-voltage coil directly bypasses the high-strength bobbin. The high-, low-voltage and voltage-regulating coils adopt the pressing device in the radial direction and the axial direction when winding, and the locking struts are used on the outer diameter side to increase the spoke firming measures;
◆The coil is vacuum dried, fully assembled, and the coil height is adjusted repeatedly during the reassembly process to ensure that the height of the final high and low voltage regulating coils is completely consistent, that is, the coil is stably treated. The laminated wooden blocks are all pre-densified, chamfered and deburred, and the parts are pressed evenly to ensure the mechanical strength and sufficient pressing force to improve the axial strength of the coil.
◆When the high-voltage, low-voltage, and voltage-regulating coils are wound, the geometric dimensions of the coil itself are ensured. The dimensions of the coils in the assembly center are closely matched with each other. The between the paper tube and the iron core is firmly supported by the struts. The sleeve is bundled and supported in a series of combined processes, and the parts are not clamped and unstable when subjected to short-circuit electric power.
◆The lead wire is fixed and encrypted, and the components adopt self-locking and anti-loose structure to meet the dynamic heat stability during short circuit.
◆The coil spoke fastening adopts “zero” margin design, uniform and sufficient drying between the iron core and the low-voltage coil paper tube, between the low-pressure, high-pressure, voltage-regulating coil and between the stay and the coaming plate. The entire coil has excellent tightness and concentricity.
◆Insulating materials in the raw materials, semi-finished products and final assembly of the body at all stages of the use of strict, standardized dry sealing and storage, to avoid uncontrollable moisture absorption expansion deformation and dimensional changes such as: insulating cardboard and processed blocks, pressure ring, etc. All are placed in a dedicated constant temperature drying cylinder for storage and storage.
◆After the drying of the distribution transformers body, strictly follow the exposure time in the atmosphere to prevent the insulation from absorbing a large amount of moisture expansion and deformation.