IEC 62053-23 Ed. 1.0 b:2003

applies only to newly manufactured static var-hour meters of accuracy classes 2 and 3, for the measurement of alternating current electrical reactive energy in 50 Hz or 60 Hz networks and it applies to their type tests only. For practical reasons, this standard is based on a conventional definition of reactive energy for sinusoidal currents and voltages containing the fundamental frequency only.