What is the significance of x r ratio?

Why is the X/R ratio important? Its importance is that it affects the level of short circuit current a circuit breaker is required to interrupt. When a short circuit occurs, the rms value of the symmetrical fault current is determined by the system source voltage and the total system impedance to the point of fault.

What is XR ratio of transformer?

All Answers (3) Hitachi, Ltd. The XR Ratio of a transformer is the imaginery portion (j), of the impedance divided by the Real part.

What is X R ratio of transmission line?

The ratio of X to R is greater than one for the transmission line and distribution line. In underground distribution networks (cables) the X/R ratio is very small and maybe smaller than 1.

What is the ratio of AC & DC component when fault occurs?

Before the fault, only AC voltages and currents are present, but immediately after the fault, both AC and DC currents are present. initially average about 50 – 60\% of the AC current flow the instant after the fault occurs. The total initial current is therefore typically 1.5 or 1.6 times the AC component alone.

Why X R ratio is high in transmission lines?

In Transmission Lines the Deq which is the Geometric Mean distance among conductors is very larger than overhead distribution lines. So the X/R ratio in transmission lines is larger than distribution lines.

How is XR ratio calculated?

The X/R ratio is the amount of reactance X divided by the amount of resistance R which also happens to be the Tangent of an angle created by reactance and resistance in a circuit. When calculating short circuit currents, there are usually many impedances that must be added together.

Why X R ratio is high in transmission line?

What is corona effect in electrical system?

Corona Discharge (also known as the Corona Effect) is an electrical discharge caused by the ionization of a fluid such as air surrounding a conductor that is electrically charged. Corona discharge can cause an audible hissing or cracking noise as it ionizes the air around the conductors.

What causes DC offset in power systems?

When the voltage is zero in an inductive circuit, the current must be maximum. Therefore the maximum DC offset occurs when the voltage is zero. Remember that when the A-Phase voltage is zero, the other two phases will not be at zero, so different phases will react to the same fault differently.