Calculate IDMT Relay Setting for Over Current & Earth Fault

Over Current & Earth Fault Setting Calculations

This document provides an overview and guidance on setting calculations for overcurrent and earth fault relays. It discusses the different types of relays, including definite time and inverse time relays. The document outlines the steps for performing setting calculations, including determining required technical data, protection schemes, relay functions, and submitting calculations for approval. Examples are provided for setting calculations for an autotransformer and 11kV feeder. Key considerations like minimum generation, circuit breaking capacity, and time grading are also addressed.

Reference : Wikipedia https://en.wikipedia.org/wiki/Protective_relay

1. Calculate Actual Operating time according to Various IES Curve.
2. Calculate LT & HT Side Low current Setting(I>).
3. Calculate LT & HT Side High Current Setting(I>>)
4. Calculate LT & HT Side Actual Operating Time of Relay(t>)
5. Calculate LT & HT Side Actual Operating Time of Relay(t>>)

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