Mell What is source impedance ratio?
B. Source Impedance Ratio. The source impedance ratio (SIR) is a voltage divider measure that provides the voltage seen by the relay for an out- of-zone fault [3] [6]. Voltage restrains impedance-based elements, so a low voltage at the relay for an out-of-zone fault increases the impact of error and transient overreach …
How do you calculate impedance ratio?
Impedance ratio = a2 = 400 Z1 = a2ZL = 400 x 9.6 = 3840 ohms.
What is the significance of the impedance ratio?
The percent impedance (%Z) is the percent of the rated load impedance possessed by a transformer. The percent impedance is important in that it allows us to: Calculate available fault currents (both individual and bank). Determine whether two transformers are suitable for paralleling.
Which is the correct formula for impedance ratio?
The impedance ratio is 0.25Ω to 4Ω or also 1:16. It can be also calculated with this Impedance Ratio formula: where n A is the number of primary turns on the winding with more turns, n B is the number of turns on the winding with less turns, and r i is the impedance ratio.
How to calculate voltage after impedance matching circuit?
To calculate the output voltage after the matching circuit, we need to know the ratio of impedance, in our case, 1500 Ω/75 Ω=20. The voltage ratio (like turns ratio in transformers) is equal to the square root of the impedance ratio, so √20≈8.7.
What is the impedance ratio of a 25 turn transformer?
With our 25:1 turns ratio transformer in figure 2, the impedance ratio is the turns ratio squared or, 25 X 25 = 625:1. So if the transformer is working into an 8 ohm load, the impedance that will be reflected to the primary will be the impedance ratio (625) multiplied by the load impedance (8 ohms), equal 5,000 ohms.
What is the meaning of impedance in Electrical Engineering?
In electrical engineering, electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied.