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Why do synchronous motors have reactance grounding but synch alternators have resistance grounding?
Wiki User
∙ 11y ago
remember the power flow equation
Pm-Pe = Pa(accelerating Power) = 2H/Ws ddelta/dt
1. synchronous generator resistance grounding -
when system suffer any kind of the disturbance which results in Pa accelerating power increases due to increase in Pe electrical power.to keep the balance between Pe and Pm, we reduce the increase amount of Pe electrical power by dissipated in the resister. from above equation we can easily make understand the Pm= Pe (in stability condition)
2. synchronous motor inductance grounding -
Reverse explanation in case of motor
Wiki User
∙ 11y ago
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In order to reduce inductive reactance what devices are normally placed on transmission or distribution lines?
== == Add a capacitor or a synchronous motor or a phase advancer to the transmission line so that it can nullify the effect of inductive reactance since the above elements gives capacitive reactance. Doing this also improves the power factor.
What is difference between impedance and reactance?
Impedance is the net reactance(for Capacitors and inductors in the circuit) / Resistance of the circcuit whereas reactance is the prperty of the individual passive components ( only capacitors n inductors) to resist the flow of charge.
Total opposition to current flow in an AC circuit with both resistance and reactance is called?
Impedance.
Inductive reactance has a unit in?
Ohms, resistance in an inductor increases as the frequency of the AC signal increases, this "artificial resistance" is called impedence, and it is measured in ohms
What is the resistance of an inductor called?
The resistance of an inductor is generally referred to as the series resistance, sometimes noted as RL. Note that resistance is a DC measurement and that an "ideal" textbook inductor has an RL of 0. The reactance of an inductor is an AC measurement which measures the reaction of a component's current flow to an alternating voltage and is frequency dependent and directly proportional to the inductor's inductance, measured in Henrie's. The impedance is most commonly used when talking about inductors or capacitors and is a combination of resistance and reactance.
Why neutral of generator is resistance grounded and neutral of motor is reactance grounded?
You can use resistance or reactance grounding on generators and motors. My understanding is resistance grounding is often used to limit ground fault currents to a few amperes, while reactance grounding will limit fault current to less than the three phase fault current. If reactance grounding is used to limit fault current o very little (like resistance grounding), transient overvoltage problems can occur.
What is synchronous reactance in alternator?
The overall reactance of the armature winding is the sum of its leakage reactance plus fictitious reactance, which is known as synchronous reactance (Xs).Xs=XL+Xarwhere XL and Xar are in Ω/phase. Therefore, Xs is in Ω/phase.The impedance of armature winding is obtained by combining its resistance and its synchronous reactance.
What is synchronous reactance?
Synchronous Reactance (in a generator analysis domain) is and equivalent series per-phase inductance term (think per-phase winding resistance) and is mainly composed of the machine's per-phase leakage inductance (equivalent series inductance of primary and secondary flux leakage) and armature reaction (distortion in flux introduced by an armature current in a machine, once again on a per-phase basis; described as a series inductance). L_SyncReac=L_leakage+L_ArmatureReaction. That sort of touches the surface of synchronous reactance.
Why and how is reactance grounding done?
Reactance grounding is done to lower ground fault current amounts, often to protect generators. It's done by tying the neutral of a generator to a grounding reactor (the other side of the reactor is tied to ground).
What is the opposition to the current flow?
resistance is the opposition to the flow of electric charge
What is difference in resistance and reactance?
Resistance is a concept used for DC. the current through a resistance is in phase with the applied voltage Reactance is used for AC the current through a inductive reactance lags the applied voltage by 90 degrees. the current through capacitive reactance leads the applied voltage by 90 degrees. the net reactance is the difference between inductive and capacitive reactance
Why is the grounding conductor flat?
When stranded conductor is being used for earthing, It offers some reactance in addition to the resistance of the conductor. Since any kind of surge is of sudden in nature, and reactance opposes the change in flow of current (Property of Inductor), It might disturb the discharge rate of the surge. Hence the conductor is flat inorder to provide only the resistance
What is relationships of capacitive reactance to resistance?
when ever current passing through any two parallel transmission line than due to the dieletric property of conductor some what capacitance effect will be generate between them that phenomina called as capitance reactance/////////////////// that symply we can called capitance reactance is measure of capitance The reactance of a capacitor is its resistance.
What do you measure with ohm?
Impedance, resistance, and reactance.
What is the reason that capacitive reactance measured in ohms?
Because it is. Capacitive reactance is a form of resistance, along with inductive reactance. All are measured in ohms.
Why in DC it is called as Resistance and impedance in AC Circuits?
Resistance applies to both d.c. and a.c. circuits, and is determined by the resistivity, length, and cross-sectional area of a conductor.In d.c. circuits, resistance is the only opposition to the passage of current. However, in a.c. circuits, the flow of current is opposed, not only by resistance, but also by reactance. Reactance is caused by a circuit's inductance or capacitance, or both, and varies with the frequency of the supply. Like resistance, reactance is also measured in ohms.So, in a.c. circuits, the combination of resistance and reactance is called 'impedance'.Impedance is not the algebraic sum of resistance and reactance, but the vectorial sum. So if, for example, an a.c. circuit had a resistance of 3 ohms and a reactance of 4 ohms, the impedance would be 5 ohms, not 7 ohms.
What has the author Kamal Koshal written?
Kamal Koshal has written: 'Direct and quadrature-axis synchronous reactance measurement'
