Answer :
Final answer:
The relay Plug Setting (PS) is 104A. The question you've asked is about finding the Plug Setting (PS) of an earth fault relay. In an electrical system, the current transformer (CT) ratio is key to determining settings for protective relays. option (a) is correct answer.
Explanation:
The relay Plug Setting (PS) can be determined using the formula: PS = (Fault Current) × (Operating Time) / (Current Transformer Ratio) × (Time Multiplier Setting) PS = (400A) × (1.3s) / (5) × (1.0) PS = 104A Therefore, the relay Plug Setting (PS) is 104A. To calculate the Plug Setting for the relay, the secondary fault current is determined using the CT ratio, which is then divided by the relay rating. Given a 400A fault current and a 400/5 CT ratio.
The Plug Setting for the earth fault relay is found to be 1. The question you've asked is about finding the Plug Setting (PS) of an earth fault relay. In an electrical system, the current transformer (CT) ratio is key to determining settings for protective relays. Given a 400/5 CT, where the primary current is 400A, and the relay type is an earth fault 5A, 1.3 seconds type IDMTL relay with a Time Multiplier Setting of 1.0.
We must calculate the appropriate plug setting that would operate for a fault current of 400A in 1.3 seconds. Firstly, we need to convert the primary fault current to the secondary of the CT using the given ratio. Secondary fault current = Primary fault current / CT ratio Secondary fault current = 400A / (400/5) Secondary fault current = 5
