Electric Circuit Analysis: Unit IV: Three phase circuits
Balanced star connected load
Three phase circuits
The 3 phase generators supply energy to the loads which may be connected either in star or delta. When the load impedances in all the three phases are identical, the load is said to be balanced.
BALANCED STAR CONNECTED LOAD
The
3 phase generators supply energy to the loads which may be connected either in
star or delta. When the load impedances in all the three phases are identical,
the load is said to be balanced.
Fig.4.8
shows a balanced star connected load of impedance Z in each phase.
Z
= | Z | ∠ ϕ
... (i)
In
the 3 phase 4 wire system the neutral point N of the supply is connected to the
star point S of the load. The wire NS is called neutral wire.
It
is seen that INa = IR = IRS .. (ii)
That
is the current in phase a of the alternator = current in line a = current in
phase R of the load
Also
INb = IY = IYS … (iii)
Also
INC = IB = IBS … (iv)
Thus,
the currents flowing through the voltage sources flow through the line
conductors and through the load elements.
Hence
IL = Iϕ for star connection .. (v)
The
given star connected load is equivalent to three single phase circuits.
By
applying, KCL at the star point S
In
= IR + IY + IB … (ix)
As
the line currents (or phase currents) form a balanced system,
Electric Circuit Analysis: Unit IV: Three phase circuits : Tag: : Three phase circuits - Balanced star connected load
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Electric Circuit Analysis
EE3251 2nd Semester 2021 Regulation | 2nd Semester EEE Dept 2021 Regulation