188.8.131.52 PHAS Test
The accuracy is given as:
AT = AR+AC+AV+AN
AT is the total accuracy (°)
AR is the basic relative accuracy (°)
AC is the calibration accuracy (°)
AV is the correction for voltage level (°)
AN is the correction for turns ratio (°)
The value of AR is given in the table in section 1.1 of this chapter.
The values of the other factors are given below.
AC = 0.000005% x FM
AV = 0.002 ((1 / VP ) + (TR / VP ))
AN = 0.05 ( | VP - (VP / TR) |)
FM is the measurement frequency (Hz)
VP is the measured voltage across the primary winding (V)
TR is the turns ratio between the primary and secondary windings