Z = √(L/C)
C = L/Z²
C = 50*10⁻⁹/(50*50)
C = 0.02 nF
C = 20 pF
Related Question
Rotor frequency, f_r = s*f_s
s = 2/50
s = 0.04
Ns = 120f/P
Ns = 1500 rpm
s = (Ns - Nr)/Ns
Nr = Ns(1 - s)
Nr = 1500*(1 - 0.04)
Nr = 1440 rpm
Equation of operating time for IDMT relay (t) = 0.14*TMS/[(PSM^0.02) - 1]
Here,
PSM = TMS = 1
So,
t = 0.14*1/(1 - 1)
t = infinite
In bias differential protection for transformer,
There are two basic settings required to setup the percentage biased differential protection.
1. Minimum pickup
2. The slope.
The minimum pick-up covers the transformer magnetizing current typically 1-4% of transformer rating.
A pick up of 0.2 to 0.3 times the TAP is recommended for general cases.
The slope is defined by determining the potential sources of differential current.