Q: Table I and Equation (1) show IDMT characteristics of three Relays R1, R2 and R3....
Data of busbar 1 to busbar 4 are given in Table 1. Relay Maximum Fault Current Transformer Primary & Secondary R1 1000 Amp 100/5 Amp R2 2000 Amp 200/5 Amp R3 4000 Amp 400/5 Amp Calculate the Relay Operating Time (ROT) of all relays. Relay R3 is having two setting of ROT.
Part B (20 marks) Figure 2 shows a three phase 22kV, 50Hz radial system, which is to be protected by two inverse- time over-current relays B1 and B2. The maximum loads for this system are L 6 MVA, and L2- 5 MVA. The maximum fault currents at bus 1 and bus 2 are 1500A and 1000A respectively. The minimum fault currents at bus 1 and bus 2 are 900A and 650A respectively The line currents are measured using current transformers...