.PowerSystems.AC3ph.Sensors

Information

Sensors output terminal signals (voltage, current, power) in a defined reference system chosen by the user.

Meters allow choosing base-units for output variables.

Comment on the sign-definition of reactive power:

From a mathematical point of view, it would be desirable to define power in the following way:

  p_active = v*i
  p_reactive = (J*v)*i

with

  J = [0,-1,0; 1,0,0; 0,0,0]

the rotation of pi/2 in the positive sense.

This definition keeps all coordinate systems positively oriented. The power-vector then can be interpreted as current-vector, normalised by voltage and transformed into a positively oriented coordinate system, whose first axis is given by the voltage vector v, and second axis by J*v.

From a practical point of view it is more convenient to use the inverse sign for reactive power, in order to obtain positive reactive power in the standard-situation of power-transfer across an inductive line. We adapt the sign-definition to this practical convention:

  p_reactive = -(J*v)*i

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