Which of the following codes and device names are incorrect?
A. 21-Distance Relay, 40-Loss of Excitation Relay, 59-Overvoltage Relay
B. 32-Power Direction Relay, 60V-Voltage Balance Relay, 87-Differential Relay
C. 27-Undervoltage Relay, 37-Undercurrent Relay, 78-Out of Step relay
D. 49-Frequency Relay, 50-Instantaneous Overcurrent Relay, 51-Time Overcurrent Relay
Show Answer
Answer: D
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