CSP (Completely Self Protected) Transformers

A CSP (Completely Self-Protected) transformer carries its own protection package inside the tank. Instead of relying on separately mounted fuses, breakers and arresters on the pole or in the substation, the protective devices are built into the unit and coordinated with the winding design at the factory. The result is a transformer that protects itself against lightning surges, secondary short circuits and sustained overloads — with fewer components to install, coordinate and maintain. DATSAN manufactures CSP transformers from 10 kVA to 2500 kVA, for systems up to 36 kV.

These three devices are selected and coordinated together: the secondary breaker is set to operate before the primary link, so a downstream fault removes the load without disconnecting the transformer from the network. Service is restored by resetting the breaker rather than replacing a fuse — a meaningful difference on rural feeders where crew travel time dominates outage duration. An overload signal light and an external operating handle with emergency reset are provided so that line crews can identify and clear a trip without opening the tank.

Note: Protection device ratings are coordinated with the transformer design and the characteristics of the network it will serve. Final power, voltage ratio, impedance, protection settings and accessory configuration are confirmed at quotation stage and guaranteed in the test report.