Operation Of Static Var Compensator Research Articles

A Novel Machine Learning-Based Framework for Optimal and Secure Operation of Static VAR Compensators in EAFs

A static VAR compensator (SVC) is a critical component for reactive power compensation in electric arc furnaces (EAFs) that is used to relieve the flicker impacts and maintain the voltage level. A weak voltage profile can not only reduce the power-quality services, but can also result in system instability in severe cases. The cybersecurity of EAFs is becoming a significant concern due to their cyber-physical structure. The reliance of SVC controllers on reactive power measurement and network communications has resulted in a cyber-vulnerability point for unauthorized access to the EAF, which can affect its normal operation. This paper addresses concerns about cyber attacks on EAFs, which can cause network communication issues in measurement data for SVCs. Three significant and different types of cyber attacks that are launched on SVC controllers—a replay attack, delay attack, and false data injection attack (FDIA)—were simulated and investigated. In order to stop the activities of cyber attacks, a secured anomaly detection model (ADM) based on a prediction interval is proposed. The proposed model is dependent on a support vector regression and a new smooth cost function for constructing the optimal and symmetrical intervals. A modified algorithm based on teaching–learning-based optimization was developed to adapt the ADM’s parameters during training. The simulation’s outcomes on a genuine dataset showed the strong capability of the proposed model against cyber attacks in EAFs.

Optimal switching strategy of an SVC to improve the power quality in a distribution network

This study presents a scheme for improvement of power quality in electrical distribution systems using a static VAr compensator (SVC). The switching of the SVC has been controlled with an objective to improve the overall power quality at the distribution level. The reduction of the degree of unbalance and improvement of power factor along with minimisation of harmonics injected into the system due to the operation of SVC are identified as the objectives of the SVC switching scheme. The proposed scheme can minimise a wider range of harmonics injected into the system without any external filter. The optimised switching angles have been calculated using the particle swarm optimisation technique. An artificial neural network has been designed to predict the optimum triggering angles and the performance of the scheme for fast changing loads has been evaluated in the laboratory using a data acquisition system. Practical evaluation of power quality has been carried out at each stage of simulation and experimentation to highlight the effectiveness of the proposed scheme. The results obtained from the proposed scheme have been compared with other recent works to prove the efficacy of the system.

Optimal planning and operation of static VAR compensators in a distribution system with non‐linear loads

This study presents an innovative design for the optimal sizing, placement, and dispatch approach of distribution static var compensators (D-SVCs) in a radial power distribution system to improve the technical and economic aspects of the grid. The approach incorporates the total harmonic distortion (THD) effects into the assessment with the presence of non-linear loads. A multi-state particle swarm optimisation algorithm is also proposed, at first to select the placement and size and then to select the dispatch strategy of D-SVCs. Three IEEE test systems were used for the case study to show the efficacy of the method. The results reveal that the approach is viable, and it determines the cases where the highest savings were achievable fulfilling the grid voltage and THD constraints.

A Balanced Operation of Static VAR Compensator for Voltage Stability Improvement and Harmonic Minimization

AbstractThe conduction angles variation in operating a static var compensator can be used to meet the balanced and varying cyclic load of reactive power demand. However, this operation creates harmonics current into the system. An optimum combination of balanced reactive power from SVC and reactive power from the generator based on telephone influence factor (TIF), the total harmonic current factor (IT), and the distribution factor D is proposed. This approach is simulated to a typical distribution network. However, this operation creates harmonics currents into the AC system. This strategy is implemented to a conventional distribution network for various loading conditions is presented.

Improving the Penetration of Wind Power with Dynamic Thermal Rating System, Static VAR Compensator and Multi-Objective Genetic Algorithm

The integration of renewable energy sources, especially wind energy, has been on the rise throughout power systems worldwide. Due to this relatively new introduction, the integration of wind energy is often not optimized. Moreover, owing to the technical constraints and transmission congestions of the power network, most of the wind energy has to be curtailed. Due to various factors that influence the connectivity of wind energy, this paper proposes a well-organized posterior multi-objective (MO) optimization algorithm for maximizing the connections of wind energy. In this regard, the dynamic thermal rating (DTR) system and the static VAR compensator (SVC) have been identified as effective tools for improving the loadability of the network. The propose MO algorithm in this paper aims to minimize: (1) wind energy curtailment, (2) operation cost of the network considering all investments and operations, also known as the total social cost, and (3) SVC operation cost. The proposed MO problem was solved using the non-dominated sorting genetic algorithm (NSGA) II and it was tested on the modified IEEE reliability test system (IEEE-RTS). The results demonstrate the applicability of the proposed algorithm in aiding power system enhancement planning for integrating wind energy.

Evaluación de la Distorsión Armónica debida a la Operación del Compensador Estático de Potencia Reactiva en la Subestación Chorrillos

La subestación Chorrillos 500/230 kV, la cual forma parte del plan de expansión del nuevo sistema de 500 kV del Ecuador, incorpora en una de sus bahías un Compensador Estático de Potencia Reactiva (SVC por sus siglas en inglés). Este equipo permite un control de voltaje en la barra de 230 kV de esta subestación a través del uso de tiristores para el control de corriente. Sin embargo, la maniobra de estos dispositivos semiconductores produce distorsiones en la forma de onda de corriente y voltaje.
 Por lo antes mencionado, el presente trabajo muestra la modelación del SVC en el programa computacional PowerFactory, y determina, para diferentes escenarios de operación, el efecto del contenido armónico sobre el Sistema Nacional de Transmisión (SNT).
 El resultado del efecto armónico provocado por este equipo sumado al contenido armónico preexistente en el SNT permite determinar si los armónicos de voltaje y corriente se encuentran dentro de los límites establecidos en la regulación CONELEC 003/08.
 Adicionalmente se analiza el K-Factor y Factor K en los transformadores del SNT, considerando el efecto armónico producido por la operación del SVC

Study on a Voltage Estimation of Tap‐Changing Transformer in Consideration of SVC Introduction

SUMMARYRecent years, installation of photovoltaic (PV) system is active by the environmental problem and feed in tariff system. Due to PV's output fluctuation, the static var compensator (SVC) made by power electronics technology is planning to install in distribution system. The SVC is expected for maintain the voltage. But SVC differs in a theory of operation of the existing voltage controller load ratio control transformer (LRT) and step voltage regulator (SVR). Because the SVC operation makes the system impedance changes, the existing voltage controller may not operate effectively. In this study, the intelligent‐control method which used the radial basis function (RBF) network is proposed. This method can reduce the effects of the SVC operation by including the performance characteristics of SVC in the conventional method. An advantage of unnecessary arrangement attention of the SVC setup node and easy cooperation with the existing equipment is obtained by applying this method.

Distributed Generation Hosting Capacity Evaluation for Distribution Systems Considering the Robust Optimal Operation of OLTC and SVC

With the rapidly increasing penetration of renewable distributed generation (DG), the maximum hosting capacity (MHC) of a distribution system has become a major concern. To effectively evaluate the ability of a distribution system to accommodate DGs, this paper proposes an MHC evaluation method while considering the robust optimal operation of on load tap changers (OLTCs) and static var compensators (SVCs) in the uncertain context of DG power outputs and load consumptions. The proposed method determines the DG hosting capacities corresponding to different conservative levels. Furthermore, this paper discusses how to find out the most critical technical constraint that may limit the MHC by adjusting parameters of the proposed robust formulation. The effectiveness of the proposed method is demonstrated using a modified IEEE 33-bus distribution system.

Three‐layer coordinated control of the hybrid operation of static var compensator and static synchronous compensator

Aiming at the problems that static var compensator cannot suppress the voltage flicker and the cost of static synchronous compensator is expensive, a three-layer hybrid reactive power compensation scheme was proposed in this study based on the expert-decision, differential-slope voltage regulation, and the expert-decision subsystem combining with fuzzy self-tuning proportional–integral (PI) control. By switching in a dynamic load which can always change the bus voltage, the whole system was simulated under the much reactive power shortage and the less shortage. The simulation results verify the effectiveness of the proposed coordinated control method in the reactive compensation and the suppression of the voltage flicker.

無効電力制御器の導入を考慮したタップ切替変圧器の電圧推定に関する検討

Recent years, installation of PV system is active by the environmental problem and feed in tariff system. Due to PV's output fluctuation, the Static Var Compensator (SVC) made by power electronics technology is planning to install in distribution system. The SVC is expected for maintain the voltage. But SVC differs in a theory of operation of the existing voltage controller Load Ratio control Transformer (LRT) and Step Voltage Regulator (SVR). Because the SVC operation makes the system impedance changes, the existing voltage controller may not operate effectively. In this study, the intelligent-control method which used the RBF network is proposed. This method can reduce the effects of the SVC operation by including the performance characteristics of SVC in the conventional method. An advantage of unnecessary arrangement attention of the SVC setup node and easy cooperation with the existing equipment is obtained by applying this method.

Combined Operation of SVC, PSS and Increasing Inertia of Machine for Power System Transient Stability Enhancement

In this paper improvement of transient stability by coordination of PSS (Power System Stabilizer) and SVC (Static var Compensator) and increasing inertia of synchronous machine has been observed. Because single method is not sufficient for improving stability. For this purpose a 9 bus multi machine system has been considered. Transient stability improvement has been tested subjected to three phase fault at bus 3 after 0.5 second and fault has been cleared after 1 second. By the use of PSS, SVC and by increasing inertia method for the test system the electromechanical oscillation for generator electrical power has been reduced and the steady state power transfer has been enhanced. In this paper the Inertia of the machine is not so much increased. Because after increasing inertia of the machine rotor will be havier.so that it is kept always within limit as considering its reliability and economy. And field voltage is also kept limited.

Combined operation of SVC and optimal reclosing of circuit breakers for power system transient stability enhancement

This paper proposes the coordinated operation of optimal reclosing of circuit breakers and Static Var Compensator (SVC) for enhancing the transient stability of a multi-machine power system. The transient stability performance of the combined operation of optimal reclosing of circuit breakers and SVC is compared with that of the combined operation of conventional reclosing of circuit breakers and SVC. The total kinetic energy (TKE) of the generators in the system is used to determine the transient stability enhancement index. Simulations are performed through Matlab/Simulink software. Simulation results for both the three-line-to-ground (3LG) and single-line-to-ground (1LG) permanent faults at different points of the power system indicate that the proposed combination of optimal reclosing of circuit breakers and SVC can enhance the transient stability of the system well. Also, the performance of the proposed method is better than that of the combined operation of conventional reclosing of circuit breakers and SVC.

Lab-Scale TCR-Based SVC System for Educational and DG Applications

Motivated by the development of power semiconductor technologies, flexible ac transmission systems (FACTS) devices and their penetration in the field of electrical power systems, an educational challenge in complementing theoretical knowledge with practical experience is recognized. In this paper, the design and implementation of a lab-scale hardware and software setup is presented. Three small-scale devices, including a static VAr compensator (SVC) unit, a transmission line model, and a substation, are developed. The SVC unit is validated by obtaining its operating characteristic. The lab setup is presented as a platform to carry out different experiments related to the SVC operation. Safety considerations in the design are discussed. Steady-state and dynamic analysis are presented showing the consistency between theory and practice. The potential use of small SVC units on low-voltage distributed generation schemes is discussed.

Harmonic Reducing ANN Controller for a SVC Compensating Unbalanced Fluctuating Loads

This paper presents the development of an artificial neural network (ANN) controller for a Static Var Compensator (SVC) system compensating unbalanced fluctuating loads. The proposed controller can balance and reduce the reactive power drawn from the source under unbalanced loads while keeping harmonic injection to the system due to SVC operation low. The first stage of controller development is a fuzzy logic based control algorithm. This algorithm determines a number of possible operating states of SVC for a given load condition and calculates corresponding harmonics injections. Then a fuzzy logic system is used to rank those operating states in terms of the magnitude of the reactive power drawn from the source and the harmonic injection level indicated by Total Demand Distortion (TDD). The best operating state is selected based on the ranking score assigned by the fuzzy logic ranking system. Finally, computational speed of the controller is improved by replacing the analytical and fuzzy computations by a set of neural networks trained with data generated with fuzzy logic based controller.

Normal form analysis of stressed power systems: incorporation of SVC models

In this paper a comprehensive analytical technique based on normal form theory and symbolic computer algebra is proposed for the analysis of non-linear inter-area oscillations in stressed power systems that incorporate the operation of Static VAR Compensators (SVCs). A second-order representation of the power system is derived that considers the explicit representation of synchronous machines and multiple SVCs in the state representation. On the basis of this model, normal form theory is used to study non-linear power system behaviour following large disturbances. The proposed approach is general and may be extended to include other FACTS devices. A simplified 4-machine, 11-bus test system is used to study the effect of SVC voltage support on system damping.

Digital simulation, transient network analyzer and field tests of the closed loop control of the Eddy County SVC

A static VAr compensator (SVC) was installed at the Eddy County substation near Artesia, New Mexico. It was put into commercial operation in April 1992. Before the commissioning period, a phase of extensive testing and analysis of the digital closed loop control was undertaken. This work was done using the actual control hardware and software in conjunction with an analog TNA and with digital simulation models of control and power systems. Results of this work were checked with the power system during field commissioning of the SVC. This paper gives an overview of the closed loop control design. It presents some results from the TNA tests, digital simulation and commissioning field tests of the SVC operation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>