The polarity mark of an instrument transformer is usually connected to which point?

The polarity mark of an instrument transformer is typically connected to the line because this ensures correct phase relationship and accurate measurement. The line connection represents the high voltage side in a typical transformer setup, and it establishes the reference point for proper operation. When the polarity mark is connected to the line, it guarantees that the secondary side of the transformer reflects the primary side's voltage accurately. This connection is critical for applications such as metering and protection in electrical systems, where maintaining the correct phase relationship between the primary and secondary circuits is essential for reliable performance.

Connections to ground, neutral, or load do not provide the necessary phase accuracy that is required for effective operation in metering applications. Connecting the polarity mark to these points could lead to incorrect readings or even damage to the instruments over time. Thus, connecting to the line ensures that the system functions as designed.