EP007
Electrical
- Apr 1, 2008
- 47
To characterize their system, the power company provides a frequency scan, which is the equivalent impedance at each frequency, output from their software (CYMDIST). At each frequency they give a number (magnitude) for each of the phases A,B,C, all different. I see three apparent issues with that format.
First, angles are also needed but not available. Imagine that at some frequency, their system looks like a capacitor (R-jX), and resonates with my plant which is inductive, R+jX.
Second, what are the 3 impedances, phase A, B, C? There can only be one positive sequence impedance, not 3. Are they the diagonals of a phase impedance matrix, Zabc? Then the off-diagonals are needed also, and the provided format is insufficient.
Third, no known industrial simulation software can work with data in the format provided.
Can anyone give me some help on this?
First, angles are also needed but not available. Imagine that at some frequency, their system looks like a capacitor (R-jX), and resonates with my plant which is inductive, R+jX.
Second, what are the 3 impedances, phase A, B, C? There can only be one positive sequence impedance, not 3. Are they the diagonals of a phase impedance matrix, Zabc? Then the off-diagonals are needed also, and the provided format is insufficient.
Third, no known industrial simulation software can work with data in the format provided.
Can anyone give me some help on this?
