What is the importance 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 X R ratio in distribution system?
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.
What occurs due to the difference of x R ratio of the source and that of faulty feeder?
For a three phase short circuit in the system during a fault all three phase sags will be of equal magnitude called balanced fault. Phase-angle jumps during three phase faults are due to a difference in the X/R ratio between the source and the feeder.
Why XR ratio is high in transmission lines?
in a power distribution system, Length of lines are much shorter than power transmission lines. there fore the inductance of power line has a low value. Therefore, the resistance of the distribution network is high which results in high R/X ratio.
What is X R rating?
The X/R ratio affects the dc component, and therefore, also the total current. The higher the X/R ratio of a circuit, the longer the dc component will take to decay (longer time constant). To illustrate, two circuits are shown in Figure 1.
What is Z in transformer?
The percentage impedance of a transformer (Z%) is the voltage drop on full load due to the winding resistance and leakage reactance expressed as a percentage of the rated voltage. The ratio of voltage applied to circulate full load current to the primary voltage is the percentage impedance of the transformer.
What is X R ratio of generator?
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.
What is MHO relay?
A mho Relay is a high-speed relay and is also known as the admittance relay. In this relay operating torque is obtained by the volt-amperes element and the controlling element is developed due to the voltage element. It means a mho relay is a voltage controlled directional relay.
What is a typical X R ratio for a transmission line?
For distribution circuits, X/R is lower, and, although data is limited, typical values are 10 (at source point) and 2-4 on a medium voltage overhead line.
What are X R ratios?
What is base kVA?
Voltage in equations (KV) is the secondary transformer voltage, line to line. Base KVA is 10,000 in all examples. Only those components actually in the system have to be included, each component must have an X and an R value. Neutral size is assumed to be the same size as the phase conductors.
What does dyn 11 mean?
Dyn 11 means that the voltage of the secondary star winding lead the primary phase voltage by 30 degree and it corresponds to 11 o’clock. You are welcome to read more Important Interview Questions and MCQs.
How does the X / are ratio affect the DC component?
· The DC component makes the symmetrical current become asymmetrical. The X/R ratio affects the dc component, and therefore, also the total current. The higher the X/R ratio of a circuit, the longer the dc component will take to decay (longer time constant). To illustrate, two circuits are shown in Figure 1.
What is the X / are ratio of a power circuit?
First, X/R ratio is simply the ratio of the system reactance to the system resistance, looking back to the power source from any point in a power circuit, assuming that a short circuit is applied to the system at that point.
What should the X / are ratio of a lvcb be?
The LVCB was tested at X/R of 6.6 (0.15 power factor). This test X/R ratio is not provided on the circuit breaker nameplate. (For reference, high voltage circuit breakers are typically tested at X/R ratio of 17. Special purpose generator circuit breakers are typically tested at X/R ratio of 50.)
What is the importance of the P / V ratio?
The P/V ratio, which establishes the relationship between contribution and sales, is of vital importance for studying the profitability of operations of a business. It reveals the effect on profit of changes in the volume.