G. Arguello

Bio: G. Arguello is an academic researcher. The author has contributed to research in topics: Electric power system & Phasor. The author has an hindex of 4, co-authored 7 publications receiving 41 citations.

Cenace's experiences on implementing a wide area monitoring system (WAMS) in the Ecuadorian power system

Abstract: The improvement of synchronized phasor measurement technology has enabled the development of new methodologies in order to monitor, in real time, high stressed operating conditions that might eventually cause problems of steady-state angle or voltage stability, as well as oscillatory stability risks. In this paper, the main components of the wide area monitoring system (WAMS) and phasor measurement in electric power systems are described. Then, a description of the WAMS system installed in the electric system of Ecuador is presented. A summary of the experiences of the Ecuadorian ISO (Centro Nacional de Control de Energia — CENACE) as regards WAMS implementation is presented. These experiences include the installation of 22 phasor measurement units (PMU), a high speed communication system based in optical fiber, and a phasor data concentrator (PDC) located in the control center. PDC functions are: to manage the phasor information and to provide dynamic monitoring applications (among which are the monitoring of steady-state angle and voltage stabilities and oscillatory stability). Finally, each of the stability monitoring applications is described and some analyses of the information obtained from the installed WAMS system are performed, presenting also the first results. These analyses will allow future operative and process design improvements, both in the planning and operation in real time, which will lead to optimize the security and reliability of operation.

Monitoreo de la Estabilidad de Voltaje de Corredores de Transmisión en Tiempo Real a partir de Mediciones Sincrofasoriales

Abstract: La determinacion de las curvas Potencia-Voltaje (P-V) y de la capacidad de transferencia disponible son las herramientas mas utilizadas para analizar la estabilidad de voltaje en los sistemas de potencia Con el desarrollo de la tecnologia de medicion sincrofasorial, nuevas herramientas de monitoreo de estabilidad de voltaje en tiempo real han sido desarrolladas Una de las herramientas mas promisorias es la tecnica del Equivalente Thevenin, la cual permite calcular la proximidad entre el estado operativo actual y el colapso de voltaje a traves de la determinacion de la curva P-V en tiempo real Este metodo esta siendo empleado principalmente para monitorear la estabilidad de corredores de transmision puesto que permite determinar la robustez relativa del sistema de transmision respecto de las barras de carga Este articulo presenta una descripcion conceptual del metodo del Equivalente Thevenin para monitoreo de la estabilidad de voltaje de corredores de transmision a partir de mediciones sincrofasoriales Se presenta adicionalmente la herramienta de monitoreo en tiempo real que dispone el CENACE y se describe una propuesta metodologica para determinar los limites de transferencia de potencia por los corredores monitoreados Estos limites serviran como base referencial para evaluar la estabilidad de voltaje en tiempo real Computation of Power-Voltage (P-V) curves and the corresponding available transfer capability are the most commonly used tools to analyze the power system voltage stability The emerging synchronized phasor measurement technology has allowed the development of novel methodologies to monitor the power system voltage stability in real time One of the most promissory techniques is the so-called Thevenin Equivalent method, which allows computing the proximity of the actual operational state to the voltage collapse via the determination of the P-V curve in real time This tool is being mainly used for monitoring the voltage stability of transmission corridors since it permits determining the power system relative strength in regards to the load buses One of the main challenges of real-time monitoring is to determine adequate early-warning indicators In this connection, this paper proposes a methodology for determining the voltage profile power transfer limits of the monitored transmission corridors These transfer limits are the referential framework for assessing the voltage stability in real time, and constitute the early-warning indicators

Architecture of a Systemic Protection System for the Interconnected National System of Ecuador

Abstract: This document describes the relevant aspects of the design of a Systemic Protection System - SPS (Remedial Action Scheme - RAS) implemented in the Ecuadorian Power System. The SPS is an automatic protection system designed to maintain power system reliability by detecting abnormal or predetermined system conditions and taking corrective actions in order to avoid a grid collapse in Ecuador. In this connection, CENACE studied n-2 contingencies of some 230 kV transmission lines of the trunk transmission system during heavy load conditions, which might trigger undesirable problems such as area separation and even possible blackouts. The study results have led to tables of mitigation actions that must present a quick response in real time (less than 200 ms) in order to mitigate the possible consequences. The mitigation actions comprise tripping of computed quantities of generation and load shedding at previously specified locations or regions. The main functional components of the SPS include: field devices, central controller systems (CCS), and communication networks. The mitigation of any specific condition will be carried out via SPS a central controller programming that allows sending monitoring and tripping signals to IEDs placed at suitable locations.

Real-time monitoring of steady-state and oscillatory stability phenomena in the Ecuadorian power system

Abstract: The emerging synchronized phasor measurement technology has allowed the development of novel methodologies to monitor the power system steady-state angle and voltage stability, as well as oscillatory stability, in real time. In this connection, the Ecuadorian ISO, CENACE, has installed a Wide Area Monitoring System (WAMS) in order to monitor this kind of stability phenomena. One of the main challenges of real-time monitoring is to determine adequate early-warning indicators. Thus, this paper presents three methodologies for determining adequate thresholds regarding: i) phase angle difference, ii) voltage profile power transfer of transmission corridors, and iii) oscillatory issues. These limits are the referential framework for assessing stability in real time, and constitute indicators that give the operators real-time early-warning signals in case of possible risk of system stress conditions.

Applied Cosimulation of Intelligent Power Systems: Implementing Hybrid Simulators for Complex Power Systems

Abstract: Smart grids link various types of energy technologies, such as power electronics, machines, grids, and markets, via communication technology, which leads to transdisciplinary, multidomain systems. Simulation packages for assessing the system integration of components typically cover only one subdomain, while greatly simplifying the others. Cosimulation overcomes this by coupling subdomain models that are described and solved within their native environments, using specialized solvers and validated libraries. This article discusses the state of the art and conceptually describes the main challenges for simulating intelligent power systems. The article "Cosimulation of Intelligent Power Systems: Fundamentals, Software Architecture, Numerics, and Coupling," published in the March 2017 issue of this magazine [88], covered the fundamental concepts of this topic, and this follow-up article covers the applied aspects of the subject.

Nonlinear Model Reduction in Power Systems by Balancing of Empirical Controllability and Observability Covariances

Abstract: In this paper, nonlinear model reduction for power systems is performed by the balancing of empirical controllability and observability covariances that are calculated around the operating region. Unlike existing model reduction methods, the external system does not need to be linearized but is directly dealt with as a nonlinear system. A transformation is found to balance the controllability and observability covariances in order to determine which states have the greatest contribution to the input-output behavior. The original system model is then reduced by Galerkin projection based on this transformation. The proposed method is tested and validated on a system comprised of a 16-machine 68-bus system and an IEEE 50-machine 145-bus system. The results show that by using the proposed model reduction the calculation efficiency can be greatly improved; at the same time, the obtained state trajectories are close to those for directly simulating the whole system or partitioning the system while not performing reduction. Compared with the balanced truncation method based on a linearized model, the proposed nonlinear model reduction method can guarantee higher accuracy and similar calculation efficiency. It is shown that the proposed method is not sensitive to the choice of the matrices for calculating the empirical covariances.

Stealthy cyber attacks and impact analysis on wide-area protection of smart grid

Abstract: Smart grid is vulnerable to many cyber attacks due to legacy nature of the infrastructure coupled with increase in control and monitoring functions through cyber advancements. Remedial Action Scheme (RAS), widely used for wide area protection, provides autonomous operations through the RAS controller. Due to its dependence on the timely cooperation of multiple devices and communication network, it is highly vulnerable to cyber attacks. In this paper, we present an impact analysis for the power system due to a class of malware-based coordinated cyber attacks targeting the RAS scheme. Specifically, we make the following two contributions. First, modeling a stealth attack vector based on malware and coordinated attack behavior. In particular installing the malware (Trojan horse) in the RAS controller which turns the controller into an attacker's bot. Then, performing a coordinated attack which involves malicious tripping of one of the parallel lines connected to a generator followed by the continuous pulse attack on the generator. The pulse attack includes periodically changing the generations through RAS controller which remains undetected by the control center. Second, testbed-based implementation and evaluation to quantify system impacts. We have leveraged Iowa State's PowerCyber CPS security testbed for experimental evaluation. In our evaluation, we varied the duty cycle of the pulse attack to obtain different attack scenarios and consequent impacts are analyzed on modified IEEE 9-bus system in real-time simulation. Our studies show that the duty cycle of the pulse attack is a critical factor in determining the severity of the attack impacts on system stability.

Precise equivalent model of small hydro generator cluster and its parameter identification using improved Grey Wolf optimiser

Abstract: With the total installed capacity of small hydro generator cluster (SHGC) continues to grow rapidly, the effect of SHGC will have affected to the security and stability of the main network in China, especially to power oscillations of passageway of ultra-high-voltage AC and DC. Thus, a precise equivalent model of SHGC is proposed in this study. In the proposed model, the fifth-order model of generator is adopted as the equivalent generator model, the excitation system is simplified into proportional feedback control model and exponential load model is used as equivalent load model. In addition, Grey Wolf optimiser with chaotic local search is designed to identify the parameters of the equivalent model. Finally, the proposed equivalent technique is applied in one simulation experiment and one practical experiment. The experimental results demonstrate that the validity and accuracy of the proposed equivalent model and identification method in solving dynamic equivalent of SHGC in engineering practice.