Directional Overcurrent Protection Principle: For the main bus-bars in the power stations, due to their importance in the operating conditions, it is required that the disconnection be without any delay in the case of faults.…
Frame Leakage Protection of Busbar or Fault Bus Protection: Frame Leakage Protection of Busbar or Fault Bus Protection is one of the most simple form of protection and is applicable to small size metal-clad switchgear.…
Backup Protection of Busbar: Backup Protection of Busbar is the simplest of all to protect the buses with the aid of backup protections of the connected supplying elements which should respond to any fault appearing…
Frame Leakage Protection of Transformer: Frame Leakage Protection of Transformer - The transformer is mounted insulated from the ground, as illustrated in Fig. 12.14. The transformer tank is connected to earth through a CT to…
Differential Magnetic Balance Protection for Transformers: This differential magnetic balance protection system is necessarily a combination of circulating current and self balance protection systems. The main advantages of this differential magnetic balance protection system are…
Harmonic Restraint Differential Relay for Transformer Protection: The operation of the relays because of magnetising inrush current can be avoided by using kick fuses across the relay coils or using relays with inverse and definite…
External Fault Backup Protection for Generators: Overcurrent and earth fault protection is provided for backup protection of large sized (above 1 MVA) generators protected by differential protection against external phase-to-phase faults and earth faults. The…
Negative Sequence Protection of Generator against Unbalanced Loads: If, owing to a fault, there is an imbalance in the three-phase stator currents, double frequency currents are induced in the rotor core. This causes overheating of…
Generator Rotor Field Suppression and Neutral Circuit Breaker: In the event of a fault on a generator winding even though the generator circuit breaker is tripped, the fault continues to be fed as long as…
Rotor Overheating Protection Diagram: Rotor Overheating Protection is provided only in case of large generators. It indicates the level of temperature and not the actual hot spot temperature. In the arrangement shown in Fig. 11.20,…
