There are different types of protective relays available now. They can be broadly classified in to the following types. Electromagnetic attraction type relays Solenoid Type Attracted Armature Balanced Beam Type Induction Type Induction Disc Type Induction Cup Type Direction Type Reverse Current Type Reverse Power Type Relays based on timing Instantaneous Type Definite Time Lag Type Inverse Time Lag type Distance type relays Impedance Type Reactance Type Admittance Type Differential Type Relays Current Differential Type Voltage Differential Type Other Types Under voltage, current, power relay Over voltage, current, power relay Thermal Relay Rectifier Relay Permanent Magnet Moving Coil Relay Static Relay Gas Operated Relay