An overcurrent relay set to operate at \(10 \mathrm{~A}\) is connected to the \(\mathrm{CT}\) in Figure 10.8 with a 500:5 CT ratio. Determine the minimum primary fault current that the relay will detect if the burden \(\mathrm{Z}_{\mathrm{B}}\) is

(a) \(1.0 \Omega\),

(b) \(4.0 \Omega\), and

(c) \(5.0 \Omega\).

Figure 10.8

Transcribed Image Text:

500 100 8 Secondary exciting volts-E' 0.1 300:5- 0.001 600:5 ||||| 500:5 450:5 +++++ 400:5 0.01 50:5 I 100:5 150:5 Till 200:5 FIL 250:5 0.1 1 Secondary exciting amps-. 10 100 CT ratio 50:5 100:5 150:5 200:5 250:5 300:5 400:5 450:5 500:5 600:5 Secondary resistance 2 0.061 0.082 0.104 0.125 0.146 0.168 0.211 0.230 0.242 0.296