Post on 17-Feb-2017
Saxion University of Applied Science
Power systems analysis 3 phase systems
Saxion University of Applied Science
Overview op presentation Review of the theory:
Three phase system
Power calculations in single and 3 phase networks
Power triangles
Single line
Saxion University of Applied Science
Three phase system
Voltages in 3 phase system
3LL
LN
VV VLN = V line–neutral,
VLL = V line–line or just V line LNLL VV 3
,
A
B
C
N
Z star Z Y
A
B
C
Z delta Z Δ
Saxion University of Applied Science
Three phase system
ABC Sequence
120LAB VV
0LBC VV
240LCA VV
90LNAN VV
30LNBN VV
150LNCN VV
N
A
BC
Saxion University of Applied Science
Three phase system
CBA Sequence
240LAB VV
0LBC VV
120LCA VV
90LNAN VV
30LNBN VV
150LNCN VV
N
BC
A
Saxion University of Applied Science
Power in 3 phase symmetrical system
Apparent power: LLLLLNph IVIVS 333
Average power: cos3cos33 LLLLLNph IVIVP
Quadrature power: sin3sin3 LLLLLN IVIVQ
Saxion University of Applied Science
A
B
C
N
Z star Z Y
A
B
C
Z delta Z Δ
3phase systems Single line
Single line – for symmetrical loads
VLN
Simple representation of 3 phase systems (1 line instead of 3 or 4 lines) ! Assumption is that the loads are symmetrical
Z = 1/3 Z