Three-phase circuit analysis involving Fortescue's symmetrical component method of solving unbalanced conditions. The method replaces the three-phase unbalanced network with three balanced networks (positive sequence, negative sequence, and zero sequence) for calculation.
Questions tagged [symmetrical-components]
10 questions
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How to transform the line voltages to the phase voltages in control software?
Let's say I am measuring line voltages of the three phase grid 400V/50Hz via three instrument transformers whose secondary windings are connected to the adc of my microcontroller i.e. I have following configuration
The control algorithms inside the…
Steve
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3
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1 answer
What type of an induction motor is used in a single-phase non-inverter household refrigerator?
There are many pictures with the 2-phase non-symmetrical (start winding and main winding) on the internet in a single-phase non-inverter household refrigerator.
What type of squirrel cage induction motor is used in a single-phase non-inverter…
Imyaf
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3
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1 answer
Actual Line-to-Line voltage from per unit value
In this question, I am able to find the per unit phase voltages using the symmetrical components. Taking the base MVA and base voltage to be the same as that of the alternator,
\$ (I_a)_1 = \frac{E_a}{Z_1 + Z_2 + Z_0} \$ where \$ Z_1 \$, \$ Z_2 \$…
curious_direwolf
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2
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Sequence Impedance/Zero Sequence Impedance of lines
I am trying to calculate the Sequence Impedance/Zero Sequence Impedance of couple of lines, but Im not sure if the calculation are right, and besides there are some tricky things on the data provided.
Tower (in meters)
• PS30
• Nominal voltage…
riccs_0x
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Calculate zero sequence voltage and current in a HV network with one source and two feeders
My goal is to prove the direction and magnitude of Uo and Io seen by the two protection relays during a single phase to earth fault in LINE 1.
By my understanding this can be done by setting up a sequence network diagram and using symmetrical…
sinB
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Symmetrical Components - Three-phase D-Y transformer with unbalanced voltage and loads
I have a Delta-Wye transformer, N1/N2 = 4, and am trying to solve the circuit below, with 120VAC applied to terminals VAB only. On the secondary I have 1 ohms connected between a-n and 5 ohms between b-n. The other parameters are:
rs = resistance of…
Charles Wagner
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5 answers
Phase voltage from unbalancd line voltages symmetrical components
I'm trying to calculate the phase voltage of a given unbalanced sources star connected from the given line voltages. I'm trying to employ symmetrical component synthesis to find a solution.
I know the zero sequence component of line voltage is…
spaul
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How to decompose the three phase unbalanced grid into the symmetrical components?
Let's I have three phase voltage grid which is unbalanced. The phase voltages are sampled by the adc and I would like to determine in the C language software the positive sequence, negative sequence and zero sequence (i.e. symmetrical components).…
Steve
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Zero Sequence current Understanding
In literature zero sequence current is called DC component. If it was DC component then how a zero sequence current in neutral grounded secondary of a transformer cause current in neutral grounded primary?
Also why in zero sequence circuit (figure…
Zarzisur
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How did they arrive at an expression for resistance given the power of the load?
In Anderson's 1995 Analysis of Faulted Power Systems, there is the below example
I am required to calculate the sequence network for the fault occurring at C. To calculate the resistance of the load, they have
$$
R\ =\ \frac{(V_u)^2 (S_B) P}{P^2 +…
