In the following question on symmetrical components, the 11kV of the source is the line-to-line voltage. When using symmetrical components you want to be working with line-to-neutral voltage. Am I right in saying this? In the memo for this question the 11kV is devided by squareroot 3 in order to obtain the phase voltages. Initially I used the 11kV without dividing by squareroot 3. How would I determine which path to follow (divide or not by squareroot 3), by looking at this question? Is there a standard which I should always follow, or am I missing key words in the question which tells me exactly what to do?

I am fine with the rest of the question, I'm just confused in determining the phase voltages. Thank you

"A 11 kV source delivers power to a power system with terminal voltages at rated value. A fault occurs in the source and it causes the b-phase voltage Vbn of the source to fall to zero (not an open circuit). With the a-phase voltage Van of the source as the zero reference, calculate the sequence network voltages V0, V1 and V2."

  • \$\begingroup\$ In addition to the question: It states that the terminal voltages are at rated value. Is it correct to say that the rating is 11kV and the terminal voltage are the voltages between lines a-b, b-c and c-a? In that case the 11kV will be line-to-line voltage which results in the phase voltage being 11kV divided by squareroot 3. \$\endgroup\$ Commented Dec 3, 2015 at 10:04
  • \$\begingroup\$ yes.. in a 3 phase distribution network the voltage is usually stated as being phase to phase. \$\endgroup\$
    – Spoon
    Commented Dec 3, 2015 at 13:14

1 Answer 1


Usually when talking about 3 phase machines, the voltage is indicated by line to line. It is easy to remember this because the terminals that are accessible by the operator are a, b, and c. So a measured or applied voltage would only be between a-b, b-c, or a-c. Which is line to line.


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