115. Concept on Traction Metering Principle

Traction transformers are generally rated with 132/25 kV, connected across 132 kV (Phase to Phase) on the primary side and 25 kV load (Phase to Earth) on the secondary side. The rating of the transformer is calculated on the basis of primary voltage available across it and current it draws from this voltage. Rated VA = (Line Voltage across x Line Current through). So for this type of Traction load, the Line Voltage is regarded as the “Driving Voltage” to which the current to the system will lead or lag, according to the type of voltage. Metering on the primary side depends on the concepts of the connection of the load from the available voltage across the primary side. Different methods used for such loading system have been discussed in this article with relevant vector diagrams. Some of the practical case studies have also been covered to decide upon the current metering principle for the traction load.