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Advanced frequency control strategy for power systems with high renewable energy penetration

Figure 7. The modified IEEE 39-bus system integrating solar farms, wind farms, and the battery energy
storage system

kV system were provided by the Vietnamese Na- (ii) Generator G6, with a capacity of 650 MW,
tional Load Dispatch Center. experiences a fault and trips out of the
The BESS model was developed from the orig- power system.
inal BESS model in the DIgSILENT PF appli-
cation manual. The control system has been 4.2.1. Scenario 1
modified to align with the objectives of this re- This case is considered unfavorable. The PV1 and
search, and all parameters for the proposed con- PV2 power plants suddenly reduced their output
trol method, as shown in Figure 5, are listed in to the grid due to cloud cover affecting the solar
Table 2.
system for a period of 50 s. The sudden loss of a
4.2. Test case 1: Applying the IEEE large amount of solar-powered capacity in such a
39-bus system short period can significantly impact the system
and cause frequency fluctuations. As shown in
For this case, the simulation was performed based Figure 9a, solar radiation drops sharply from 907
on consideration of two scenarios as follows: to 77 W/m during the cloud cover within 20 s.
2
(i) Large cloud cover that can vary the inten- After the clouds disperse, solar radiation recovers
2
sity of solar energy radiation and cause sig- and jumps back to 998 W/m as the sky clears
nificant fluctuations in the output power of and the plants return to stable operation. This
the two solar farms of PV1 and PV2. scenario represents a negative situation inspired
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