Electrotechnical Systems

27Models of Power Circuit Devices

The lters contain R, L, C elements. The values of these elements are determined

by the following data: the lter type, the reactive power under the rated voltage, the

tuned frequency or frequencies, and quality factor. Four lter types that can be simu-

lated in SimPowerSystems are shown in Figure 2.12.

For the simplest lter—single-tuned lter—the following relationships are

valid [1]:

XLX

C

Lc

==

ω

ω

,

1

(2.5)

The order of the ltered harmonic (here f

1

is the fundamental frequency)

n

f

f

X

X

n

==

1

c

L

(2.6)

The quality factor

Q

nX

R

X

nR

Lc

==

(2.7)

The reactive power at frequency f

1

Q

V

X

n

n

c

c

=

22

2

1

()

−

(2.8)

AB C

AB C

AB C

AB

R

L

1

C

C

1

C

1

C

2

C