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Transient angle stability of inverters equipped with the robust droop controller is investigated in this work. At first, the conditions on the control references to guarantee the existence of a feasible post-disturbance operating point are derived. Then, the post-disturbance equilibrium points are found and their stability properties are characterized. Furthermore, the attraction regions of the stable equilibrium points are accurately depicted by calculating the stable and unstable manifolds of the surrounding unstable equilibrium points, which presents an explanation to system transient stability. Finally, the transient control considerations are provided to help the inverter ride-through the disturbance and maintain its stability characteristics. It is shown that the transient angle stability is not a serious problem for droop controlled inverters with proper control settings.
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Efficient Simulation of Cascading Outages Using an Energy Function-Embedded Quasi-Steady-State Model
This paper proposed an energy function-embedded quasi-steady-state model for efficient simulation of cascading outages on a power grid while addressing transient stability concerns. Compared to quasi-steady-state models, the proposed model incorporates short-term dynamic simulation and an energy function method to efficiently evaluate the transient stability of a power grid together with outage propagation without transient stability simulation. Cascading outage simulation using the proposed model conducts three steps for each disturbance such as a line outage. First, it performs time-domain simulation for a short term to obtain a post-disturbance trajectory. Second, along the trajectory, the system state with the local maximum potential energy is found and used as the initial point to search for a relevant unstable equilibrium by Newton's method. Third, the transient energy margin is estimated based on this unstable equilibrium to predict an out-of-step condition with generators. The proposed energy function-embedded quasi-steady-state model is tested in terms of its accuracy and time performance on an NPCC 140-bus power system and compared to a quasi-steady-state model embedding transient stability simulation.
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- Award ID(s):
- 2329924
- PAR ID:
- 10572160
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Transactions on Power Systems
- ISSN:
- 0885-8950
- Page Range / eLocation ID:
- 1 to 10
- Subject(s) / Keyword(s):
- Cascading outages quasi-steady-state model transient stability energy function transient energy margin
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1109/TPWRS.2025.3527811
