'Apparent power' is a term used in a.c. circuits, NOT d.c. circuits.
when excitation fails,Reactive power will be supplied by the system to which the generator is connected and generator will work as induction generator and its speed will rise a little. generator which was in over excitation mode will work in underexcitation.but there is under excitation limit which should not be reached so we should detect loss of excitation and trip generator
The ratio of apparent power to true power is called 'admittance', expressed in siemens. Admittance is the inverse of impedance.
Real Power: The actual power in Watts or K-Watts in AC or DC Circuits Apparent power: The Power in Inductive or Capacitive Circuits have Phase Lag & Lead measured in Volt Amperes VA or Kilo Volt Amperes KVA
In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)
Apparent power is the product of voltage and current in an a.c. system, and is expressed in volt amperes. The rated apparent power of a transformer is the product of its rated secondary current and rated secondary voltage.
If the DC excitation is reduced in a synchronous machine, the apparent power will generally decrease. This is because the reduction in excitation leads to a lower magnetic field strength, which can cause a decrease in the machine's ability to produce reactive power. As a result, the overall apparent power, which is the combination of real and reactive power, will also decline.
Hi, Under excitation - inductive reactive power Over excitation - Capacitive reactive power.
Static excitation refers to a method of supplying direct current (DC) to the rotor windings of a synchronous machine, such as a generator, to establish a magnetic field. This excitation is "static" because it typically involves the use of a stationary power source, like a rectifier, to convert AC voltage from the generator into DC. The static excitation system allows for precise control of the machine's output voltage and reactive power, enhancing stability and performance. It contrasts with dynamic excitation systems, which use rotating equipment to provide excitation.
No. The volt ampere (V.A) is the unit of measurement of apparent power. Power factor is true power (expressed in watts) divided by apparent power (expressed in volt amperes).
when excitation fails,Reactive power will be supplied by the system to which the generator is connected and generator will work as induction generator and its speed will rise a little. generator which was in over excitation mode will work in underexcitation.but there is under excitation limit which should not be reached so we should detect loss of excitation and trip generator
The ratio of active power (real power) and apparent power is called power factor ( pf ). Power Factor ( pf ) = Active Power / Apparent Power = .................. ( kvar )
If a load takes 50 kW at a power factor of 0.5 lagging calculate the apparent power and reactive power Answer: Apparent power = Active power / Power Factor In this case, Active power = 50 kW and power factor = 0.5 So Apparent power = 50/0.5 = 100 KVA
Apparent Power=Active Power+Reactive Power or Active Power=VI Cos(Phase Angle) Reactive Power=VI Sin(Phase Angle) Apparent Power= VI
The ratio of apparent power to true power is called 'admittance', expressed in siemens. Admittance is the inverse of impedance.
Real Power: The actual power in Watts or K-Watts in AC or DC Circuits Apparent power: The Power in Inductive or Capacitive Circuits have Phase Lag & Lead measured in Volt Amperes VA or Kilo Volt Amperes KVA
Synchronous generators supply reactive power (measured in kilovolt-amperes reactive or KVAR) by adjusting their excitation level. When the excitation is increased, the generator can produce more reactive power, which is essential for voltage regulation in the power system. Conversely, if the excitation is decreased, the generator can absorb reactive power. This ability to control reactive power makes synchronous generators crucial for maintaining system stability and voltage levels in electrical grids.
Excitation failure occurs when a generator or synchronous machine fails to maintain its magnetic field, leading to a loss of voltage and stability. This can result from issues such as a malfunctioning excitation system, loss of a power supply to the exciter, or mechanical failure. The consequences can include decreased system performance, potential damage to equipment, and disruptions in power supply. Proper monitoring and maintenance of the excitation system are crucial to prevent such failures.