What type of protection relay is specifically designed to detect shorted turns within a hydro-generator's stator winding?

A differential relay, specifically a percentage differential relay, is most suitable for detecting shorted turns within a hydro-generator's stator winding. A shorted turn fault occurs when insulation fails between adjacent turns in a winding, creating a low-impedance path for current to flow. This results in increased current within the faulted winding and a corresponding imbalance in the currents entering and leaving that winding phase. A differential relay operates by comparing the currents entering and leaving a protected zone, such as a generator winding. Under normal operating conditions, these currents should be equal. However, during a fault, the currents will differ, and the relay will initiate a trip signal to isolate the generator. A percentage differential relay is used to improve security by considering the through current. It uses a percentage slope characteristic, meaning the relay will only trip if the differential current exceeds a certain percentage of the through current, thus avoiding false trips due to CT errors or tap changer operations. Some modern protection schemes implement advanced differential protection algorithms based on harmonic restraint or adaptive settings to further improve the sensitivity and security of the relay.