Answer / ravi

These terms appear in the calculation of fault currents.
Common sources of fault currents are rotating machines,
i.e., motors and generators. An important factor in
detrmining the magnitude of a fault current is a variable
reactance that changes rapidly after the initiation of the
fault until it reaches a steady state.

Subtransient Reactance:-usually denoted as X''d (X double
prime sub d), is the reactance used to determine the
current during the first cycle after the occurance of the
fault.
Transient Reactance:-In about 0.1 second this
reactance increases to the
level known as Transient Reactance usually denoted as X'd,
and after 0.5 to 2 seconds it increases to the leven known
as Synchronous Reactance and denoted as Xd, and this
determines the fault current after a steady condition is
reached.

Answer / chunkey pandey

These terms appear in the calculation of fault currents.
Common sources of fault currents are rotating machines,
i.e., motors and generators. An important factor in
detrmining the magnitude of a fault current is a variable
reactance that changes rapidly after the initiation of the
fault until it reaches a steady state.

Subtransient Reactance:-usually denoted as X''d (X double
prime sub d), is the reactance used to determine the
current during the first cycle after the occurance of the
fault.
Transient Reactance:-In about 0.1 second this
reactance increases to the
level known as Transient Reactance usually denoted as X'd,
and after 0.5 to 2 seconds it increases to the leven known
as Synchronous Reactance and denoted as Xd, and this
determines the fault current after a steady condition is
reached.

1)Why V cross Arm is used in transmission lines? 2)Why H cross Arm are not used in single poles?

1 Answers  

---

What is float cum boost charging system?

0 Answers  

---

what are the disadvantages of low power factor

0 Answers   HMK,

---

What are the differents between Breaker & Contactor?

8 Answers  

---

tell me about roaster switch .& what is the function in transmission & distribution?

0 Answers  

---

Is it good to short Neutral and Ground in the PLC or DCS main Power supply. Pls give YES or NO with reasons...? Simarpreet

0 Answers   Bindal Papers,

---

how to calculate vfd o/p voltage by frequency

0 Answers   HCL, Orchid,

---

how u change the vector group of a transformer like DYN1 to ynd11

2 Answers  

---

we use 3 phase supply for induction motor why not use two phase supply .

4 Answers   TLC,

---

what should be 3phase motor capacity or rating to connect in star connection. what should be 3phase motor capacity or rating to connect in delta connection. what should be 3phase motor capacity or rating to connect in star delta connection

1 Answers  

---

Slipring moter find external resistance

1 Answers  

---

What is the AVR in DG & its functios

2 Answers   Godrej,

---