Sistemas de potencia
G. Heydt S. Kalsi E. Kyriakides
Arizona State University American Superconductor
© 2003 G. Heydt, S. Kalsi and E. Kyriakides
Session Introductions 1 Fundamentals of synchronous machines
Time 8:30 – 8:40 8:40 – 9:50
Topics • Energy conversion • Synchronous machine construction • Energy transfer in a synchronous machine• Motor and generator action • Phasor diagram for synchronous machines • Losses • Superconducting designs • Power factor and torque angle • Example of calculations • Transients and damper windings • Saturation and the magnetization curve
Instructor Bradshaw Heydt
BREAK
9:50 – 10:00
2 Synchronous condensers
10:00 10:30
–
3 Superconducting 10:30 synchronous 12:00 condensers
–• What is a synchronous condenser? • Applications of synchronous condensers • Analysis • Superconductivity • The superconducting synchronous condenser (SSC) • Performance benefits of SSC in a grid
Kalsi
Kalsi
LUNCH
12:00 – 1:30
4 Synchronous machine models
1:30 – 2:30
5 State estimation applied to synchronous generators
2:30 – 3:30
• Park’s transformation • Transientand subtransient reactances, formulas for calculation • Machine transients • Basics of state estimation • application to synchronous generators • demonstration of software to identify synchronous generator parameters
Heydt
Kyriakides
BREAK 6 Machine instrumentation Question and answer session
3:30 – 3:40 3:40 – 4:30
4:30 – 5:00
• DFRs • Calculation of torque angle • Usualmachine instrumentation
Heydt, Kyriakides, and Kalsi All participants
SESSION 1
Fundamentals of synchronous machines
Synchronous Machines
• Example of a rotating electric machine • DC field winding on the rotor, AC armature winding on the stator • May function as a generator (MECHANICAL ELECTRICAL) or a motor (ELECTRICAL MECHANICAL) • Origin of name: syn = equal, chronos = timeSynchronous Machines
ROTATION
• FIELD WINDING • ARMATURE WINDING
Synchronous Machines
The concept of air gap flux
STATOR
ROTOR
Synchronous Machines
• The inductance of the stator winding depends on the rotor position • Energy is stored in the inductance • As the rotor moves, there is a change in the energy stored • Either energy is extracted from the magnetic field (and becomesmechanical energy – that is, its is a motor) • Or energy is stored in the magnetic field and eventually flows into the electrical circuit that powers the stator – this is a generator
Synchronous Machines
The basic relationships are POWER = ( TORQUE ) (SPEED)
2) ENERGY = (1/2) ( L I
POWER = d(ENERGY) / d(TIME)
Synchronous Machines
Consider the case that the rotor (field) is energized byDC and the stator is energized by AC of frequency f hertz. There will be average torque produced only when the machine rotates at the same speed as the rotating magnetic field produced by the stator. RPM = ( 120 f ) / (Poles) Example: f = 60 Hz, two poles, RPM = 3600 rev/min
Synchronous Machines
d
The axis of the field winding in the direction of the DC field is called the rotor direct axisor the d-axis. 90 degrees later than the d-axis is the quadrature axis (q-axis).
ROTATION
q
The basic expression for the voltage in the stator (armature) is v = r i + dλ/dt Where v is the stator voltage, r is the stator resistance, and λ is the flux linkage to the field produced by the field winding
Synchronous Machines
Basic AC power flow
jx
SEND
Vsend
RECEIVE
VreceiveSynchronous Machines
Vinternal
Vterminal
The internal voltage, often labeled E, is produced by the field interacting with the stator winding, and this is the open circuit voltage
GENERATOR ACTION – POWER FLOWS FROM MACHINE TO EXTERNAL CIRCUIT, E LEADS Vt
Synchronous Machines
Vterminal
Vinternal
The internal voltage, often labeled E, is produced by the field interacting with the...
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