The High Voltage (HV) and Low Voltage (LV) Bushings of Transformers that are found in transformers are necessary components that make it possible for the windings of the transformer to be connected to the electrical system outside the transformer. The transfer of electrical power between the transformer and the related high and low voltage networks is made possible by these bushings, which offer a secure and insulated conduit for the power to travel. The high voltage winding of the transformer must be connected to the external high voltage transmission or distribution system, and the HV bushings are the components that are in charge of making that connection. They are built to endure severe electrical stresses and provide insulation to prevent electrical breakdowns and ensure safe operation. This makes them suitable for the design of the product. Depending on the application and the transformer rating, high-voltage bushings are often constructed to withstand voltage levels ranging from a few kilovolts up to several hundred kilovolts. This range of voltage can be handled by the bushing.
On the other hand, low voltage (LV) bushings are what are required to make the connection between the low voltage winding of the transformer and the low voltage distribution or utilization system. In comparison to HV bushings, they are made to withstand lower voltage levels due to their design. Depending on the particular application and the rating of the transformer, LV bushings often run at voltage levels ranging from a few hundred volts to several kilovolts. This range is determined by the transformer rating. Both high-voltage (HV) and low-voltage (LV) bushings are intended to offer the windings of the transformer both mechanical and electrical insulating support. For the purpose of providing sufficient electrical insulation and withstanding the operational conditions of the transformer, they are built with insulating materials of a high grade, such as porcelain or composite materials.
The building of HV and LV bushings requires the incorporation of a number of essential components. In most cases, these will consist of a center conductor, an insulating body, and an outside housing that provides protection. The winding of the transformer is connected to the external electrical system through the use of a central conductor, which provides the electrical connection. The electrical insulation is provided by the insulating body, which is comprised of a high-quality insulating material and is wrapped around the central conductor. The insulating body is encased within the outer protective housing, which not only offers mechanical strength but also shields the body from the effects of external elements like dirt and moisture as well as mechanical strains.
Both high-voltage (HV) and low-voltage (LV) bushings can have additional features added to them to improve their performance and dependability. These features can include surge arresters to defend against transient voltage surges, grading capacitors to lessen voltage strains, monitoring devices to measure factors such as temperature and oil levels, and surge arresters to protect against transient voltage surges.It is absolutely necessary to perform thorough HV and LV bushing maintenance and inspections in order to guarantee the reliable operation of transformers. Regular visual inspections, electrical testing, and preventive maintenance should be performed on the transformer in order to identify any signs of deterioration or damage and take the proper corrective actions in order to avoid failures and ensure that the transformer will have a long lifespan.
The test tap is there so that the capacitance, Tan delta, and insulation resistance (IR) value of the bushing may be measured. It is immediately connected to the core’s final condenser foil through a copper lead, which serves as the connection. This test tap is normally electrically connected to the mounting flange trough test tap cover while it is being used in normal service. Before the screw test tap cover is put into service, it needs to have the appropriate repairs done.Due to the fact that the bushing is a self-contained unit, it is not necessary to perform any particular maintenance on it. In most cases, however, it will only be necessary to perform periodic checks on the oil level and thorough cleanings of the porcelain. During the course of the yearly maintenance that is performed, measurements of capacitance and tan delta may be taken in order to ascertain the state of the bushing’s overall health. When compared to the results of the pre-commissioning test, these values are to be evaluated. A Tan delta value more than 0.007 and an increase in capacitance greater than or equal to 10% are both required.
In a nutshell, high-voltage (HV) and low-voltage (LV) bushings are vital components in transformers. They serve to insulate the connection between the windings of the transformer and the electrical systems that are located outside the transformer and give mechanical support for the connection. They play an essential part in the process of easing the transfer of electrical power while also guaranteeing that the operation is safe and dependable. For transformers to perform well and for an extended period of time, it is imperative that they have bushings for both high voltage and low voltage that have been designed, built, and maintained correctly.