Definition of the Four Quadrants of Electric Energy Measurement
According to the provisions of "Multifunctional Electric Energy Meter Communication Protocol" DL/T645-2007, we define the horizontal axis of a plane coordinate system as active power and the vertical axis as reactive power. The two axes divide a plane into four areas , the upper right corner is quadrant I, and clockwise are quadrant II, quadrant III and quadrant IV; quadrant I and quadrant II reactive power are defined as forward reactive power, and quadrant III and quadrant IV reactive power are defined as reverse reactive power;
And has a phase angle Φ relative to the voltage phasor U. The angle Φ in the counterclockwise direction is positive. A schematic diagram of the four quadrants is shown:
P—active electric energy; Q—reactive electric energy; QL—inductive reactive energy; QC—capacitive reactive energy; S—apparent power
Note: This picture is different from the representation in the "DL/T645-2007" standard, but the content is the same.
Forward active power: P=UICOSΦ, where the range of Φ is within ±90°.
Reverse active power: P=UICOSΦ, where Φ ranges from 90° to 270°
Forward reactive power: P= UISINΦ, where the range of Φ is within 0~180° (national standard definition)
Reverse reactive power: P= UISINΦ, where the range of Φ is within 180~360° (national standard definition)
Since the voltage in Quadrant I leads the current by less than 90°, and in a purely inductive circuit, there is a phenomenon where the voltage leads the current by 90°, so when the input (forward) power is active, the reactive power generated in Quadrant I is called inductance. Reactive power; since the voltage in the IV quadrant lags the current within 90°, and in a pure capacitive circuit, there is a phenomenon that the voltage lags the current by 90°, so when active power is input, the reactive power generated in the IV quadrant is called capacitive No use. In the same way, when the output (reverse) power is active, quadrants III and II are inductive reactive power and capacitive reactive power respectively.
Power is expressed in four quadrants:
1) Forward active power: that is, the input active power, which is the power delivered by the grid to users and the power consumed by users;
2) Reverse active power: that is, the output active power, which is the power the user sends to the grid and the power generated by the user;
3) Forward reactive power: that is, the input reactive power, which is the reactive power sent by the power grid to the users and the reactive power used by the users;
4) Reverse reactive power: that is, output reactive power, which is the user sending reactive power to the grid, and the user sending reactive power;
The meaning of reactive power in the four quadrants:
1) Quadrant I reactive power: input active power, input reactive power, the user is an inductive (current lags voltage) load;
2) Quadrant II reactive power: output active power, input reactive power, user load is equivalent to an under-excitation generator;
3) Quadrant III reactive power: output active power, output reactive power, user load is equivalent to an over-excitation generator;
4) Quadrant IV reactive power: input active power, output reactive power, the user is a capacitive (current leads voltage) load;
The meaning of capacitive reactive power and perceptual reactive power:
1) Quadrant I: consumes active power and consumes inductive reactive power.
2) Quadrant II: output active power and output capacitive reactive power.
3) Quadrant III: output active power and output inductive reactive power.
4) Quadrant IV: consumes active power and consumes capacitive reactive power.