The main difference between an auxiliary relay and a normal protection relay lies in their primar...

1. **Auxiliary Relay:**
- **Purpose:** Auxiliary relays are secondary relays designed to provide additional control functions in power system protection schemes.
- **Function:** These relays are typically used to perform auxiliary tasks such as providing interlocking, trip circuit supervision, control switching, and signaling functions.
- **Operational Role:** Auxiliary relays support the primary protection relays by enhancing the overall functionality and reliability of the protection system.
- **Application:** They are commonly used in conjunction with primary protection relays to enhance the efficiency and safety of electrical systems.
2. **Protection Relay:**
- **Purpose:** Protection relays are primary relays designed to detect abnormal conditions in an electrical system and initiate protective actions to isolate the fault and safeguard equipment.
- **Function:** These relays are responsible for monitoring system parameters such as voltage, current, frequency, and phase angle to detect faults like overcurrent, overvoltage, undervoltage, and other abnormalities.
- **Operational Role:** Protection relays play a critical role in ensuring the safety and reliability of the electrical system by correctly identifying faults and initiating appropriate protective actions.
- **Application:** They are strategically placed within the system to quickly detect faults and isolate the affected sections to prevent damage and maintain system stability.
In summary, while auxiliary relays serve supplementary functions such as control, signaling, and interlocking within the protection scheme, protection relays are dedicated to detecting faults and ensuring the overall reliability and safety of the electrical system by initiating protective actions. Each type of relay plays a distinct role in the efficient operation and protection of electrical systems.