The increase in penetration levels of inverter-based resources (IBRs) is changing the dynamic performance of power grids of different parts of the world. IBRs are now being more and more integrated into the grid at a single connection point as an IBR plant. Due to the complex nature and dynamicity of each inverter model, it is not realistic to build and analyze full complex models of each inverter in the IBR plant. Moreover, simulating a large plant including detailed models of all the IBRs would require high computing resources as well as a long simulation time. This has been the main issue addressed in the new IEEE Std 2800-2022. This paper proposes a novel approach to model an IBR plant, which can capture the transient nature at the plant level, detailed IBR control at the inverter level, interactions of multiple IBR groups in a plant structure, and a collector system connecting the IBRs to the grid. The IBRs in the plant use a voltage source inverter topology combined with a grid-connected filter. The control structure of the IBR includes a cascaded loop control where an inner current control and outer power control are designed in the dq-reference frame, and a closed-loop phase-locked loop is used for the grid synchronization. The mathematical study is conducted first to develop aggregated plant models considering different operating scenarios of active IBRs in an IBR plant. Then, an electromagnetic transient simulation (EMT) model of the plant is developed to investigate the plant’s dynamic performance under different operating scenarios. The performance of the aggregated plant model is compared with that of a detailed plant model to prove the effectiveness of the proposed strategy. The results show that the aggregated EMT simulation model provides almost the same result as the detailed model from the plant perspective while the running time/computation burden is much lower.
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IBR Power Plant Frequency Control Design Consideration
Voltage control is often time provided at the plant-level control of inverter-based resources (IBR). Addition of energy storage systems in an IBR power plant makes it feasible to have frequency control at the power plant level. While frequency control appears as a simple frequency-power droop control to adjust real power commands to inverter-level controls with measured frequency as an input, care must be taken to avoid interactions among the plant frequency control with communication delays, inverter-level control effects, and the frequency sensor, usually a phase-locked-loop (PLL). This paper present two types of interaction scenarios that makes frequency control design challenging. The first interaction scenario may occur if the frequency control's gain is large, while the second interaction scenario may occur at a small control gain if the plant-level PLL lacks sufficient damping. We contribute to the fundamental understanding of the causation of stability issues due to plant frequency control through the derivation of a simplified feedback system focusing on the frequency and power relationship, and the follow-up frequency-domain analysis for gaining insights. For validation, we also design a data-driven approach to obtain models from data generated from an electromagnetic transient (EMT) simulation testbed. The findings from analysis have all been validated by EMT simulation. Finally, we contribute to mitigating strategies and also the understanding of the role of additional proportional integration power feedback control. This addition has been demonstrated as an efficient stability enhancement strategy to mitigate the effect of communication delay.
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- Award ID(s):
- 2103480
- PAR ID:
- 10584443
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Transactions on Sustainable Energy
- Volume:
- 15
- Issue:
- 4
- ISSN:
- 1949-3029
- Page Range / eLocation ID:
- 2405 to 2416
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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