Compute positive-sequence active and reactive powers
Simscape / Electrical / Specialized Power Systems / Sensors and Measurements
The Power (Positive-Sequence) block computes the positive-sequence active power P (in watts) and reactive power Q (in vars) of a periodic set of three-phase voltages and currents. To perform this computation, the block first computes the positive sequence of the input voltages and currents with a running window over one cycle of the specified fundamental frequency. These formulas are then evaluated:
V1 is the positive-sequence component of input Vabc. I1 is the positive-sequence component of input Iabc.
A current flowing into an RL circuit produces a positive P and a positive Q.
As this block uses a running average window, one cycle of simulation must complete before the outputs give the correct value. For the first cycle of simulation, the output is held constant using the values specified by the Voltage initial input and Current initial input parameters.
- Fundamental frequency (Hz)
Specify the fundamental frequency, in hertz, of the input signals. Default is
- Voltage initial input [ Mag, Phase (degrees) ]
Specify the voltage initial magnitude and phase used by the block to compute the constant output for the first cycle of simulation. Default is
- Current initial input [ Mag, Phase (degrees) ]
Specify the current initial magnitude and phase used by the block to compute the constant output for the first cycle of simulation. Default is
- Sample time
Specify the sample time of the block, in seconds. Set to
0to implement a continuous block. Default is
Inputs and Outputs
The three-phase voltage signal.
The three-phase current signal.
The positive-sequence active power, in watts.
The positive-sequence reactive power, in vars.
|Sample Time||Specified in the Sample Time parameter|
Continuous if Sample Time = 0
compares the outputs of the Power (Positive-Sequence) block with the
Power (3ph, Instantaneous) and the Power (dq0, Instantaneous) block.
The Power (Positive-Sequence) block gives ripple-free accurate results
even with the presence of zero and negative sequences in the voltage
The model sample time is parameterized by the Ts variable set
to a default value of 50e-6 s. Set Ts to 0 in the command window and
change the Simulation type parameter of the Powergui
Continuous to simulate the model
in continuous mode.