IEEE Power & Energy Magazine - May/June 2019 - 56

Figures 8 and 9 present comparisons between on-site measurements (blue curves) and real-time simulator results, with
the dc cable modeled using a frequency-dependent model (red
curves). The results show good agreement, which proves the
accuracy of the replicas and real-time model. in addition,
Figure 9 illustrates the importance of accurate modeling in a
real-time simulator; the green curve represents the real-time

Current (kA)

5
Idc Pole4 Hypersim
Idc Pole4 On-Site

4
3
2
1
0.16

0.17

0.18

0.19
Time (s)
(a)

0.2

0.21

0.22

160

(°)

120
80
Alpha P4 Hypersim [HYP1]
P4 Alpha L1

40
0
0.16

0.17

0.18

0.19
Time (s)
(b)

0.2

0.21

simulation results, with the dc cable modeled as a constant
parameter model, whereas the red curve represents the realtime simulator, with a frequency-dependent model. one can
notice the impact of the good representation of the cable
model on the results.
Validation of INELFE Replicas

The accuracy of the real-time simulator, including the
inelFe replicas, can be validated and further evaluated
by comparing the hil simulation results with several
on-site measurements. This article presents the results of
two cases: 1) a 20% active power step and 2) a blocking/
deblocking operation of the converter station during normal operation.
Figure 10 shows the results of both cases, where the curves
in red are from the replicas and the curves in blue are the onsite results. The results show good agreement between
simulation results and on-site measurements; the frequencies
and amplitudes of the oscillations are very close. These results
validate the models of the inelFe link and the surrounding
ac network. Figure 10 shows slight differences in the amplitude
of the ac voltage peak that are probably related to the modeling
accuracy of the network short circuit availability in the real-time
simulator, which seems slightly low.

0.22
Active Power

figure 8. Comparisons between IFA2000 on-site results
(blue curves) and real-time simulation results (red curves) in
terms of (a) dc current and (b) alpha delay angle.
dc Voltage
300
Voltage (kV)

200
(a)

100
0

Active Power

-100
-200
-300
0.16

0.17

0.18

0.19
Time (s)

0.2

0.21

0.22
Reactive
Power

Vdc Pole4 Hypersim
Vdc Pole4 On-Site
Vdc Pole4 Hypersim CP

figure 9. Comparisons between on-site results (blue
curves) and the real-time simulation results (red curves)
for the IFA2000 and the impact of the cable model. The
green curve illustrates the real-time simulation results, with 
the dc cable modeled as a constant parameter model. CP:
constant parameter.
56

ieee power & energy magazine

(b)

figure 10. Comparisons between on-site results (blue
curves) and real-time simulation results (red curves) for
the INELFE: (a) a converter blocking/deblocking event and 
(b) an active power step change.
may/june 2019
IEEE Power & Energy Magazine - May/June 2019

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