DIN standard LV transformer bushing 1-3KV/250-630A

The transformer bushing is an insulating sleeve that leads the high and low voltage leads inside the transformer to the outside of the fuel tank, not only as the lead wire is insulated to the ground, but also plays the role of fixed lead, the transformer bushing is one of the transformer current-carrying components, in the operation of the transformer, the load current is passed for a long time, and the short-circuit current occurs when the transformer is short-circuited outside. Therefore, the following requirements are placed on the transformer bushing:

(1) Must have the specified electrical strength and sufficient mechanical strength.

(2) It must have good thermal stability and be able to withstand instantaneous overheating in the event of a short circuit.

(3) Small appearance, small mass, good sealing performance, strong versatility and easy maintenance

STRUCTURE:

The casing is mainly composed of a capacitor core, an oil pillow, a flange, and an upper and lower porcelain sleeve, and the main insulation is a capacitor core, which is made of concentric capacitors in series, and is enclosed in a sealed container composed of the upper and lower porcelain sleeves, oil pillows, flanges and bases, and the container is filled with treated transformer oil, so that the internal main insulation becomes an oil-paper structure. The contact surface between the main components of the casing is lined with oil-resistant rubber gaskets, and each component is fully sealed by the central compression force exerted by a group of strong springs arranged in the oil conservator. The flange is equipped with a vent plug, an oil extraction device, a device for measuring the dielectric loss of the casing (tan δ, referred to as dielectric loss) and partial discharge (referred to as partial discharge). During operation, the outer cover of the measuring device must be covered to ensure that the end screen is grounded, and it is strictly forbidden to open the circuit.

There are two ways to connect the bushing and the transformer high-voltage lead, which are cable threading and guide rod current-bearing.

Operation and maintenance:

The casing should be used according to its model under its specified conditions, with attention to the following.

(1) Ensuring that the casing is sealed is the key to obtaining a durable life. The position of the sealing structure moved by the user during installation and maintenance should be carefully restored to the original sealing state.

(2) Oil level control and adjustment. The change of oil level in the casing can be observed regularly during operation, and it needs to be adjusted if it is too high or too low. When the oil level is too high, an appropriate amount of oil can be drained from the flange to the oil plug: when the oil level is too low, the transformer oil that is consistent with the grade marked on the nameplate should be added from the oil injection port of the oil conservator. For products with normal oil performance in the preventive test over the years, the cycle of the preventive test can be appropriately extended to reduce the amount of oil extracted. If in doubt, you should contact the manufacturer, and it is strictly forbidden to disassemble this casing by yourself.

The correct steps of taking oil are: remove the dirt at the flange oil plug, open the oil plug, use a special grease nozzle, slowly screw in along the central screw hole of the oil plug, resist the plug inside and screw tightly, press the sealing ring of the oil nozzle, then the transformer oil in the casing flows out along the inner hole of the oil nozzle;

Note: When unscrewing the grease nozzle, do not loosen the oil plug, if it is found to be loose, you should use the opposite side 19mm socket wrench to tighten the oil plug in time.

(3) The measuring terminal must be reliably grounded. The sleeve installation flange is provided with a measuring terminal, and when measuring the dielectric loss and partial discharge of the sleeve, the terminal cover is unscrewed, and the binding post is insulated with the flange. After the measurement, the terminal cover must be covered to ensure reliable grounding. It is strictly forbidden to open the circuit during operation.

(4) The dielectric loss value of 10kV measured on site may be inconsistent with the factory test data due to the influence of the measuring instrument, the location of the product and the measurement environment. It is recommended to use the data measured by the high-voltage Xilin bridge test plant, and the measured data under high voltage shall prevail.