Infinite bus bar in power system
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INFINITE BUS BAR IN POWER SYSTEM SUBMITTED TO SUBMITTED BY PROF. J. SANDEEP SONIEKLAVYA SHARMA
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Transcript of Infinite bus bar in power system
INFINITE BUS BAR IN POWER SYSTEMSUBMITTED TO SUBMITTED BYPROF. J. SANDEEP SONI EKLAVYA SHARMA
INFINITE BUS
Infinite bus bar is one which keeps constant voltage and frequency although the load varies. Thus it may behave like a voltage source with zero internal impedance and infinite rotational inertia.
Any alternator switched on to or off, the infinite bus does not cause any change in the voltage and frequency of the system.
EXAMPLE OF INFINITE BUS
When number of alternators are interconnected forming a system can be considered as an infinite bus.
Any alternator switched on to or off, the infinite bus does not cause any change in the voltage and frequency of the system.
INFINITE BUS CONDITION
1. System frequency is constant, independent of power flow 2. System voltage is constant, independent of reactive power consumed or supplied
INFINITE BUS F AND V PLOT
OPERATING A GENERATOR CONNECTED TO AN INFINITE BUSIf a generator is operated off an infinite bus:
1. Terminal voltage and frequency (and hence speed) are constant 2. The no-load settings of the mechanical system governor can be adjusted to supply more or less power
PHASOR DIAGRAMS
To simplify analysis and aid understanding, neglect armature resistance-
Since voltage is constant and assuming synchronous reactance is also constant, changing the power (with the mechanical system) will set E sin δ and |E| will control the reactive power. These effects can be seen be considering two cases.
1. Constant Excitation, Changing power 2. Constant Power, Changing Excitation
SYNCHRONOUS MACHINE ON INFINITE BUS-BARS
A synchronous machine connected to a network having zero impedance and infinite rotational inertias said to be operating on infinite bus-bars.
Practically all synchronous motors and generators in normal industrial use on large power supply systems can be considered as connected to infinite bus-bars.
PHASOR DIAGRAM
MATHEMATICAL EXPRESSION
From the phasor diagram in Figure, the power delivered to the infinite bus bar, P= VI cos φ per phase but,
Hence,
Power delivered =
