Browsing by Author "Wadduwage, DP"

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item: Conference-Full-text
Designing a robust controller to damp sub-synchronous oscillations in power systems
(IEEE, 2020-07) Gamage, CM; Wadduwage, DP; Weeraddana; Edussooriya, CUS; Abeysooriya, RP
Series compensation using capacitor banks is a common technique used in power transmission systems, to improve the power transferring capability. However, it may lead to the generation of some natural frequencies due to the combination of inductor and capacitor. These frequencies are called as sub-synchronous frequencies which are below the power frequency of the power systems. They can give rise to sub-synchronous resonance (SSR). The SSR can cause physical damages to the power system equipment unless it is detected and mitigated prudently. This paper presents a robust controller which can be used to damp undesirable sub-synchronous oscillations. The small signal model required to design the controller is constructed using dynamic phasor approach. The performance of the controller is demonstrated using IEEE first benchmark model (FBM) for SSR studies. It’s shown that the proposed robust controller satisfactorily work under different operating conditions.
item: Conference-Full-text
Frequency stability analysis of non-conventional renewable integrated power systems
(IEEE, 2023-12-09) Wijethunga, WMRM; Wijesena, PAHK; Samarawickrama, TD; Wadduwage, DP; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
Integrating intermittent non-conventional renewable energy sources such as wind and solar into power systems presents unique challenges for its operation. To address this, effective frequency control mechanisms are crucial. This study presents a comprehensive analysis investigating the performance of hydro and steam, in a non-conventional renewable integrated power system. The analysis aimed to enhance power system stability through the collective operation of wind and solar power plants of varying capacities, while maintaining a stable frequency. In addition, the study investigated the maximum penetration level of these resources under different contingencies. Preliminary results indicate that the hydro turbine exhibits a longer settling time and higher steady-state error compared to its steam turbine counterpart. Using a 12 bus test system simulated in PSCAD software, this research provides valuable insights into turbine performance and the feasibility of integrating renewable resources, aiding in the improvement of power system stability.
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Investigation of the applicability of Lyapunov exponents for transient stability assessment
(2015-06-30) Wadduwage, DP; Geeganage, J; Annakkage, UD
Lyapunov Exponents (LEs) measure the exponential rates of divergence or convergence of nearby trajectories in state-space models. The study presented in this paper investigates the applicability of this concept to power system transient stability analysis. It is shown that the Largest Lyapunov Exponent (LLE) of the post-fault system subsequent to a given fault scenario is independent of the fault clearing time up to the Critical Clearing Time (CCT). Furthermore, the set of exponentially stable equilibrium points of the post-fault system corresponding to different load-generation combinations of the pre-fault system can also be characterized by this LLE. The study compares the LEs with the conventional Time Domain Simulation (TDS), Extended Equal Area Criterion (EEAC) and Potential Energy Boundary Surface (PEBS) methods. It is shown that LEs give reliable results. Further, the power system stability regions can be determined using the invariance of LEs within the same stability region.
item: Article-Full-text
Stability and dynamics of active distribution networks (ADNs) with D-PMU technology: A review
(IEEE, 2022) Bu, S; Meegahapola, LG; Wadduwage, DP; Foley, AM
Massive integration of converter-interfaced distributed energy resources (CDERs) has resulted in many emerging stability issues and significantly complicated the dynamics of active distribution networks (ADNs). Large quantities of CDER systems with complex structures, time-varying parameters and ‘black-box’ controllers not only make the system modelling nearly an impossible task, but also considerably increase the dimension of dynamic models and thus the computational burden for the model-based stability analysis and control. Distribution-level phasor measurement unit (D-PMU) technology has a superior capability of monitoring, analyzing and controlling the real-time system dynamics. This paper provides a comprehensive overview on the state-of-the-art techniques of dynamics monitoring, analysis and control based on D-PMU technology in ADNs. A special emphasis is placed on the emerging instability incidents induced by CDERs. Although stability monitoring, analysis and control techniques based on PMU technology are well established in the transmission systems, substantial research efforts are required to extend these techniques to deal with the different dynamic characteristics of distribution systems. The application of big-data analytics in analyzing D-PMU data streams becomes prevalent, which can dig more information and thus provide more effective measures for stability analysis and control of ADNs.