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The depletion of conventional fuel reserves and the high carbon emissions have alarmed the energy sector drivers. The integration of renewable energy resources (RERs) towards power system transformation is an obvious approach for a new-zero future. However, this integration also brings challenges in terms of voltage stability and power losses due to the variable output of RERs. To address these challenges, this work proposes a novel approach utilizing photovoltaic (PV) inverters and static var compensators (SVCs) for reactive power control in power distribution networks (PDNs). It enhances voltage stability and minimizes power losses. The proposed study deploys a proximal policy optimization (PPO) algorithm for real-time communication and control between reactive power devices. Performance evaluation was made on an IEEE-33 Bus system to demonstrate the effectiveness of the proposed scheme in integrating RER-based distributed generators (DGs). The proposed system achieved 68 % voltage control, keeping the voltage within a certain range of ±5 % while minimizing power losses. The proposed system also reduced the voltage out-of-control ratio to 0.044, which indicates minimum voltage deviation from the standard value. The proposed study provides a promising solution for controlling the voltage of DGs integrated PDN, which can potentially enhance the efficiency and reliability of the power system. • This paper introduces PV inverters and SVC-based reactive power voltage regulation for renewable DG-integrated systems. • Reactive power control in the DG-integrated system is adopted using Reinforcement Learning-Driven PPO. • The validation of the proposed method uses the IEEE-33 bus system to integrate RERs-based DGs and achieve PPO-based control. • The proposed method achieved 68% voltage control, reduced power loss, and reduced the voltage out-of-control ratio to 0.044. • This research compares the suggested approach to different methodologies to demonstrate its validity and applicability. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes two controlling methods for SVC in smart grid with connected EV charger. • SMC, ASRFC with a HVC are separately applied in the grid. • This paper presents usage of proposed methods for decreasing size of capacitor and value of apparent power loss. • The proposed scheme is validated through computer simulations of a 22.9-kV grid. Abstract Electric Vehicles (EVs) play a pivotal role in reducing the emissions of greenhouse gases in the world. Currently demand for EVs has abruptly increased for transportation and other applications. Using more EVs causes an increasing load on the power system. Random EV charging yields voltage distortion, which results in an unbalanced grid. In a distributed system, the connection of EVs to the grid may diminish the power factor, which increases the apparent power loss. The Static VAR Compensator (SVC), which is a FACTS device, is applied to the power system to compensate the voltage distortions and apparent power loss. In this paper, two controlling methods are contemplated and tested in a SVC to reduce the apparent power loss and minimize the capacitor size of the SVC in comparison with the conventional control method in a SVC. Proposed methods are also compared with the conventional control method used for SVC. The Slide Mode Controller (SMC) and Asymmetric Synchronous Reference Frame Controller (ASRFC) with a Harmonic Voltage Compensator (HVC) are separately applied in the grid. This paper presents usage of SMC and ASRFC methods for decreasing size of capacitor and value of apparent power loss through computer simulations of a 22.9-kV grid. With application of new controllers, apparent power loss of grid will be reduced as compared with conventional method of SVC controller. Moreover, the size of SVC capacitor can also be reduced. [ABSTRACT FROM AUTHOR]

In our recent work [1] , we constructed a reduced-order model of the Western Electricity Coordinating Council (WECC) power system using mathematically derived parameters from real Synchrophasor data. These parameters include inter and intra-area impedances, inertias, and damping factors for aggregate synchronous generators representing five geographical, and yet coherent, areas of WECC. In this paper, we use this reduced-order model as a tool to design a supplementary controller for a Static VAr Compensator (SVC), located at the terminal bus of one of the aggregate generators. Wide-area feedback consisting of phase angle and frequency measurements from Phasor Measurement Units (PMUs) in the other areas is used to design this controller. The objective is to damp the inter-machine oscillation modes of the reduced-order model, which in the full-order system corresponds to inter-area oscillations. The controller input is chosen via statistical variance analysis, and its parameters are tuned to improve the damping factors of the slow modes. The model is implemented in a real-time digital simulator, and validated using a wide range of disturbance scenarios. The closed-loop system is observed to be highly robust to all of these disturbances as well as the choice of operating points. Detailed experimental analyses of the capacity of the SVC to satisfy the damping specifications of supplementary control are also presented via multiple contingencies. The results are promising in aiding damping of inter-area modes in WECC, especially at a time of increasing penetration of wind and other renewable resources. [ABSTRACT FROM AUTHOR]

In this paper, a new control synthesis framework is developed to solve a robust stabilization problem for a single-machine infinite-bus power system with a static var compensator (SVC). The uncertainties in the infinite bus voltage and the internal and external reactances to the generating station are considered. First, control inputs for the excitation and the SVC are obtained via immersion and invariance (I&I). Then, the controller is redesigned using a parameter update law and a filter using indirect I&I adaptive control and a two-time-scale technique. The transient and steady-state performances are enhanced by introducing class K functions. The simulation results show that the developed controller improves the system performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Combination of optimal reclosing of circuit breakers and SVC is proposed for power system transient stability enhancement. [•] The performance of the proposed combination of optimal reclosing and SVC is compared with the combination of conventional reclosing and SVC. [•] The performance of the proposed combination of optimal reclosing and SVC is better than that of the combination of conventional reclosing and SVC. [•] Combined operation of optimal reclosing and SVC can be considered as an effective means for power system transient stability enhancement. [ABSTRACT FROM AUTHOR]

• Yet there are few studies for the extremely short-term forecasting of wind power. • Since the proposed approach is nonlinear, it provides more accurate modelling than the ARMA approach. • The proposed approach only uses the EKF algorithm to update the parameters which makes it suitable for online implantation. • It is robust against noisy easements and probabilistic behavior of the wind speed profile. • A proper model for the wind farm to simulate and evaluate the performance of the SVC based on real data is proposed. The inherent time-varying nature of the wind farm power causes undesired voltage flicker in the power network. In order to mitigate the flicker to enhance the performance of the wind power system with very fast dynamics, the static VAr compensator (SVC) is utilized. However, the SVC operates with some delays which negatively affects its performance. This persuades us to predict the reactive power of the wind farm to compensate for the real-world delay. The predicted reactive power is then utilized in the SVC. Therefore, this paper develops a novel fuzzy one-step-ahead prediction approach for the wind farm reactive power. The proposed fuzzy prediction uses a Takagi-Sugeno (TS) fuzzy representation whose unknown parameters are tuned online based on an extended Kalman filter (EKF). The wind farm is modeled as a time-varying current source which its amplitude and phase change every 0.01 s. A large set of the actual data of a wind farm in Manjil, Iran is gathered and directly utilized in the simulation process. Several flicker indices are calculated to evaluate the proposed prediction method. The obtained results show the performance enhancement and flicker mitigation of the suggested power scheme. [ABSTRACT FROM AUTHOR]

• The main contributions of this work are summarized as follows. • Considering different load types, their outage costs, and their daily load profiles to find the best UFLS scenario with lowest interruption cost. • Performing the PLSA after UFLS by means of reactive power control apparatus. • Checking the adaptive UFLS/PLSA scenarios by transient stability analysis. • Finding the optimal UFLS/PLSA scenarios all day long. • Damping the background voltage and frequency fluctuations. The conventional under frequency load shedding (UFLS) strategies disconnect the preset amount of the load from the power grid in specific steps. These approaches ignore the daily load variations and the total outage costs, leading to a non-optimal solution. This paper proposes an adaptive UFLS scheme that considers the daily profiles of the different load types to minimize the total outage cost. To obtain the exact amount of the load to be shed, the dynamic performance of the load clusters is modeled. Furthermore, a series of post load-shedding corrective actions (PLSA) are implemented after the UFLS to satisfy the voltage constraints, using the installed reactive power control apparatus and static VAR compensators (SVCs). Two static (frequency-domain) and transient (time-domain) indexes are defined to evaluate the feasibility of possible UFLS/PLSA scenarios. The promising solutions are ranked and the most favorable ones are embedded in a number of look-up tables. The proposed UFLS/PLSA approach is applied to the main grid as well as the potential islands. The performance of the proposed adaptive UFLS/PLSA approach is tested on the IEEE 39-bus system via numerous scenarios, and the results show feasibility, fast and optimal performance of the proposed method. [ABSTRACT FROM AUTHOR]

• This method is only based on the current data in relay location. • The proposed method is completely analytical. • A negative-sequence based approach used to fault location estimation. This paper introduces an accurate fault location algorithm for double-circuit transmission lines compensated by Static Var Compensator (SVC). The proposed algorithm is based on the negative-sequence circuit of the transmission system and it depends only on the current data available from one end of the line. Since only magnitudes of current signals are required, there is no need for data synchronization. The proposed technique uses the COMTRADE fault files available from digital distance relays and it can effectively locate the all types of unbalanced faults, regardless the high fault resistance, effect of mutual coupling and SVC current injection information. As one formula can be used for all types of fault, classification of fault types and phase selection are not required. The shunt capacitances of the line are considered by utilizing the distributed parameters model of the transmission lines. The proposed algorithm is rigorously investigated for various fault scenarios in SVC compensated transmission system. The simulation cases in the MATLAB environment verifies that the proposed scheme has excellent performance. Test results are compared with a conventional fault location technique to illustrate the accuracy of the proposed algorithm. [ABSTRACT FROM AUTHOR]

The unbalanced and nonlinear characteristic of many loads connected to the power system can cause power quality problems, which in turn affects other consumers. Electric arc furnaces (EAF) are among the loads that cause major problems for system power quality. The use of static var compensator (SVC) is a way to reduce power quality problems caused by EAF. Since precise quantification of the SVC susceptance function can greatly influence the optimization of the reactive power, in this paper proposed using of a fuzzy logic controller to optimize the susceptance function to further improve the voltage profile and reduce SVC capacitance. The results from simulations show that the SVC based fuzzy method optimally determines the coefficient of the susceptance function. The results show that the proposed method with the proposed method has good performance in reduction of harmonic currents and improving the voltage profile of the system. So, the results clear that in case of EAF load, the SVC is capable of rapidly compensating its effect and improve the system power quality. By maintaining the bus voltage and eliminating voltage oscillations, the active power received is quickly stabilised and power oscillations are removed. Thus, power quality problems of EAF application is eliminated with application of optimized SVC based fuzzy method. In addition, the performance of the proposed method compared to mathematical methods in previous studies has been evaluated, which presents superiority of the proposed method in reducing voltage oscillations and reducing harmonic currents. [ABSTRACT FROM AUTHOR]