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Based on the knowledge accumulated off-line and feature extractions, a novel data-based learning and control method is proposed for the long-term voltage stability problem in this paper. All the spatial-temporal data is considered and the features of different emergency events are extracted by principle component analysis which can reduce the dimension and reveal the significant internal structure of the data. An artificial neural network is used to build a classifier to reinforce the relationship directly between the system dynamics and optimal control actions. With the prepared control knowledge, it is faster to find an optimal control action online with a good system performance. Simulation results on the 6-bus system, New England 39-bus system and Iceland 189-bus system are given to show the potential of this method for on-line control. [ABSTRACT FROM AUTHOR]

Globally,wind power plants (WPPs) installations are dramatically increasing, leading to a large-scale integration into the power grids. Huge endeavors are devoted to achieving an efficient operation of WPPs. This paper offers a novel chaotic-billiards optimizer (C-BO) algorithm to properly design the fuzzy logic control (FLC) strategy for stability enhancement of grid-integrated WPPs. The C-BO algorithm has distinct features such as simple construction, low numbers of parameters required to design, high convergence speed, and low computational burden. The permanent-magnet synchronous generator (PMSG)-based WPP is interlinked into the electric power grid through power converters. A cascaded FLC approach, which is optimally fine-tuned by the C-BO, is offered as the control methodology for these converters. The C-BO algorithm fine-tunes the gain factors of multiple FLCs at a rapid convergence speed. A simulation-based optimization approach is applied, in which the integrated square error criterion is chosen as an objective function. For the sake of preciseness, the PMSG-based WPP is connected to the IEEE 39-bus New England test system. The effectiveness of the optimal FLC using the C-BO algorithm is compared with that achieved using the water cycle algorithm-based optimal FLC, the genetic algorithm-based optimal FLC, and the marine predator algorithm-based optimal proportional-integral controller, taking into account severe grid disturbances. Moreover, real wind speed measured data captured from Zaafarana Station in Egypt are extensively performed in the system studies. The validity of the offered control approach is widely verified by the simulation analyses using the MATLAB/Simulink environment. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to damp interarea oscillations by designing a robust multi-input multioutput supplementary controller for multiterminal dc (MTDC) systems embedded in ac grids. The key idea to achieve robustness lies in explicitly modeling the MTDC current injection as disturbances using an \mathcal H\infty mixed-sensitivity formulation in the linear matrix inequality framework. Control directions are established by selecting wide-area feedback signals and the relative gain array computation. Robustness is assessed through dynamic simulations for scenarios including: first, disturbances on the ac side, second, disturbances on the dc-side such as loss of a converter pole including actuator, third, partial loss of feedback signal, and fourth, communication latencies. The performance of the proposed controller is compared against the conventional \mathcal H\infty based design, using a four-terminal dc grid embedded within the New England–New York test system. The results suggest that the proposed approach demonstrates superior performance following dc-side disturbances, actuator outages, and latency. [ABSTRACT FROM PUBLISHER]

• A systematic planning method to allocate dynamic VAR sources is proposed. • The concept of voltage control area is proposed to partition a bulk power system. • A zone-based voltage supporting index is defined in the site selection process. • A zone-based distributed optimization framework is put forward. In this paper, a practical planning method to allocate dynamic VAR sources (DVSs) using the concept of voltage control areas (VCAs) is proposed to enhance short-term voltage stability of power systems. Firstly, based on the defined transient distance index, a spectral clustering method is employed to partition a system into VCAs. Then, candidate DVS sites in each zone are determined by the proposed voltage supporting index. In each VCA, the capacity of candidate sites is preliminarily estimated by use of the dichotomy method to decide the most effective control bus and the initial capacity guess, based on which further system-wide optimization is implemented using particle swarm optimization (PSO) to obtain the final allocation scheme. Case study on the New England 39-bus and 68-bus test systems along with the comparisons with the existing methods confirm the effectiveness and advantages of the proposed methodology. [ABSTRACT FROM AUTHOR]

The dc voltage and frequency $ (PVF)$ or modified dc voltage and frequency $ (PV^{2}F)$ double droop control is commended for its ability to regulate both the dc voltage and the frequency in a decentralized approach. However, a convincing response is not achieved due to an interaction between the droop characteristics of dc voltage and frequency. This interaction affects the dc voltage and frequency support of the ac-system-surrounded multiterminal HVdc (AC-MTdc) grid. To overcome this effect, a Duo control strategy is proposed in this article, which takes advantage of a bipolar voltage-source converter topology in the MTdc grid. The virtue of the proposed control technique is emphasized by comparing it with the existing $ PV^{2}F$ double droop control along with three case studies and two test systems. The validation of the interactionless Duo control strategy is carried out on a five-terminal CIGRE dc grid benchmark model integrated into a two-area power system (AC-MTdc grid-1) and a New England IEEE 39-bus system (AC-MTdc grid-2). These test systems are simulated in PSCAD/EMTdc software. [ABSTRACT FROM AUTHOR]

A new jumping genes paradigm in the format of hierarchical genetic algorithm is proposed for optimizing the power voltage control systems. The advantage of this scheme is its unique capacity. for finding the required solutions that can be used for stabilizing the progressive voltage drop or even voltage collapse of a power system. Because of the multiobjective classification, all these solutions could therefore form a landscape of control pattern which is aptly applicable to the control purpose of the coordinated voltage control system. The application of the proposed paradigm is verified upon the New England 39-bus power system. A tradeoff between the recovery time and the quality of voltage control exists and largely depends upon the number of steps for control actions. [ABSTRACT FROM AUTHOR]

Power system transient stability control is gaining huge attention in present time. Inspired by the consistency theory of multi-agent system, a distributed finite-time frequency control framework is presented to improve the frequency dynamic of the transient process by adjusting the steam valving. The stability of the proposed distributed frequency control scheme is ensured by including the Lyapunov-based constraints. The communication delay is fully considered in the deigned distributed frequency control framework which has no limitations on communication delay by fully utilizing the local information. Meanwhile, the proposed cyber-physical topology divides the power system into several clusters according to the physical coupling between generators. The designed distributed control scheme based on the proposed cyber-physical topology owns the capability to defend denial-of-service (DoS) attacks which may influence the performance of distributed control scheme, which is also presented in theoretical proof. The designed voltage control based on the direct feedback linearization method can be applied to coordinate all existing frequency controls, in the premise of the system stability. The performance of the proposed control scheme is evaluated under the cases of different communication delays and DoS attacks through the simulation on New England 39-bus system. [ABSTRACT FROM AUTHOR]