Determine the percentage voltage error of a potential transformer with the system voltage of 11000 V and having a turn’s ratio of 104 if the measured secondary voltage is 98 V

• A. 5.75
• B. 8.84
• C. 7.92
• D. 6.25

Answer: (C)

System voltage i.e Nominal voltage = 11000 V
V1/V2 = N1/N2
98/V2 = 104
Primary = Turn ratio × Secondary voltage = 98 × 104 = 10192 V
Percentage of error is the Potential error
= (Nominal voltage − Primary voltage)/Primary voltage
(11000 − 10192)/10192
= 7.92%