The P632 is designed for the protection of transformers as well as for the protection of motors and generators and of other two-winding arrangements.

For application of the device as transformer differential protection, amplitude matching is required. This is achieved simply by setting of the reference power ‑ generally the nominal power of the transformer  ‑ and of the primary nominal voltages for all windings of the transformer.

Vector group matching is achieved by the straightforward input of the relevant vector group identification number. For special applications, zero-sequence current filtering may be deactivated. For conditions where it is possible to load the transformer with a voltage in excess of the nominal voltage, the overfluxing restraint prevents inappropriate tripping.

For application as differential protection device for motors or generators, the harmonic restraint (inrush compensation) can be deactivated. The start-up of directly switched asynchronous motors represents a problem in differential protection due to transient transformer saturation caused by a displacement of the start-up current for relatively high primary time constants. Even under these unfavorable measurement conditions, the P632 exhibits an excellent stable performance due to the application of a saturation discriminator.

All observations below are based on the assumption that the system current transformers are connected to the P632 in standard configuration (see Chapter “Conditioning of the Measured Values”). In particular, the application as transformer differential protection device presupposes that winding ‘a’ corresponds to the high voltage side of the transformer. For a non-standard connection, the appropriate settings must be selected (see Chapter “Settings”).