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Phase and Sign Conventions for Energy Meters

Technical Guide 28

The relationship between voltage and current in a system being metered can be expressed in several ways, e.g., by a power factor, a phase angle, or by describing the load as inductive or capacitive. This is straightforward when the system being metered is a net consumer of power and the phase angle is between +90° and −90°. It is less clear when the system is generating power and the phase angle exceeds 90°. pdf 216 KB