0
It depends on the nature of the transmission line mostly under a fault it is the inductance that will be limiting the fault current so your power factor would be quite low. The exact number would change from line to line.
During a fault (say three phase fault for simplicity), the power factor will drop to the line angle (assume no, or very little fault resistance). On EHV systems, this is in the 80 - 88 degree range (typically). On VHV, it is often in the 70-80 degree range. A line angle of 90 degrees is a pf of 0, so to convert between this line angle and power factor: pf = cos (line angle).
As voltage gets lower, the assumption of no fault resistance becomes less valid, and the line angle becomes less (increased power factor).
The lowest VHV line angle I've seen is in the 60-70 degree range. I've seen 40-60 on HV, and as low as 30 degrees (.86 pf) on underground cabling.
What else can I help you with?
Is it possible to transmit power with leading power factor?
The power factor depends on the properties of the load, and if any power factor correction is done it has to happen at the load, so that the current in the transmission lines is reduced. Correcting the power factor at the sending end fails to address the problem.
What is the use of an reactor in an electrical substation?
A reactor is an application for an inductor. Inductors oppose any change in current. So a reactor is used to 'slow down' (a simplification) any significant change in current arising from, say, a short-circuit fault. Answer: Reactors are also used for power-factor correction. If a transmission line has a load with a permanently poor power factor, reactors would be connected at the receiving end to correct the power factor and thus reduce the current and the power losses in the resistance of the line.
Why are transformers used to increase the voltage before transmission?
Using a higher voltage reduces power losses during transmission.
Why unity power factor is used in load test?
When power factor is at unity, the voltage and current waves are aligned or in phase with one another. Since power is the product of voltage and current, power transfer is maximized at unity power factor. When power is transmitted at a lower power factor, greater current is required to deliver the same amount of power. When current is increased, the size of the transmission, distribution and generation systems, all have to be increased accordingly, along with the price of the killowatt-hour at the meter.
Why can a reactive power load drop the voltage more than the active power load in a transmission line?
A load with a poor power factor draws extra current from the power supply, meaning that there will be more of a voltage-drop in the supply. As an example, if the load is 6 kW on a 240 v supply, the current drawn is 25 amps if the load has a power factor of 1. The kVA is equal to the kW. But if the load has a power factor of 0.8 it needs to draw 7.5 kVA for a power of 6 kW, which is a current of 31.25 amps, so there is more of a demand on the power supply wiring etc. The transmission losses increase by 56% with the extra current. In both cases the customer is charged for power used, 6 kW. That is why the supply companies do not like loads with a poor power factor and sometimes charge commercial customers more for a poor power factor. That in turn makes it viable for the customers to correct the power factor of the load they place on the supply.
Is it possible to transmit power with leading power factor?
The power factor depends on the properties of the load, and if any power factor correction is done it has to happen at the load, so that the current in the transmission lines is reduced. Correcting the power factor at the sending end fails to address the problem.
What is Fault location in transmission line?
Fault location in a transmission line refers to identifying the specific location where a fault has occurred, such as a short circuit or a ground fault. This process involves using various methods such as distance protection relays, traveling wave analysis, and fault passage indicators to pinpoint the fault location accurately. It is crucial to quickly isolate the faulted section and restore power to the rest of the transmission system to minimize downtime and maintain system reliability.
What causes low power factor?
Reactive power flow results in a lower power factor. In transmission systems, this can be due to unequal source voltages. In load networks, this is usually due to motor load.
What happen to the voltage regulation and transmission efficiency when power factor of receiving end is increased?
When the power factor is 1, that is neither capacitive or inductive, the load does not have reactance that impedes current flow. Power companies like that.
Why each phase no load power factor of 3 phase induction motor is not same?
That indicates a fault in the induction motor.
Why the sending end voltage is less than receiving end voltage in case of load with leading power factor?
The voltage is attenuated by the resistance in the media used for transmission. This is regardless of the power factor.
Are shunt reactors used in nuclear reactors?
Answer 1. The only shunt reactors I know are used on transmission lines to alter power factor. This is nothing to do with the nuclear reactor in a power plant.Answer 2. I agree. Shunt reactors are use on transmission line and EHV to boost voltage, to generate VARs and for power factor correction.
What percentage of electricity is typically lost during transmission?
On average, about 5-6 of electricity is lost during transmission from power plants to homes and businesses.
What is the use of an reactor in an electrical substation?
A reactor is an application for an inductor. Inductors oppose any change in current. So a reactor is used to 'slow down' (a simplification) any significant change in current arising from, say, a short-circuit fault. Answer: Reactors are also used for power-factor correction. If a transmission line has a load with a permanently poor power factor, reactors would be connected at the receiving end to correct the power factor and thus reduce the current and the power losses in the resistance of the line.
Why are transformers used to increase the voltage before transmission?
Using a higher voltage reduces power losses during transmission.
How is energy loss reduced during transmitted from power stations to homes?
Energy loss is reduced during transmission from power stations to homes by using high-voltage transmission lines that can carry electricity efficiently over long distances. Transformers are used to step up the voltage at the power station and step it down at the homes, minimizing energy loss during transmission. Additionally, regular maintenance of transmission lines and equipment helps to keep the system running efficiently.
What happen if generator run on leading power factor?
When the power factor is leading, the capacitive kVAr is more than the Inductive kVAr and this still has to be supplied by the source. As kVA is the vector sum of kW and kVAr, still for the given kW, you have to produce more kVA. Alternately, for the given kVA, you can only convert partially into useful work. Secondary effects are voltage boost in the system, availability of stored energy to feed the fault in case of a fault, increase in the asymmetrical component of fault current, increasing thus the peak value of the fault current, etc.
