In a biased differential relay, the bias is defined as a ratio of -

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RSMSSB JE Electrical Engineering (Degree) 19 May 2022 Official Paper

Answer 1

Biased Differential Relay:

The relay whose operation depends on the phase difference of two or more electrical quantities is known as the differential protection relay.
It works on the principle of comparison between the phase angle and the magnitude of the same electrical quantities.
In a biased differential relay, the bias is defined as a ratio of the number of turns of restraining and operating coil.

Operation of biased differential relay:

The MMF produced in the operating coil = N_o(I₁ - I₂)

The MMF produced in the restraining coil =

At balance condition:

= = No(I1 - I2)

Bias = =