Real-Time External Equivalents for Static Security Analysis

Monticelli, A.; Deckmann, S.M.; Garcia, A.V.; Stott, B.

doi:10.1109/tpas.1979.319387

Cited by 126 publications

(56 citation statements)

References 9 publications

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“…In this method, the resistance of the external circuit was ignored and therefore the external equivalent circuit only contains reactance. More details on Ward type equivalent methods and how the power industry uses these equivalent circuits in various studies can be found in the literature [101][102][103][104][105][106][107].…”

Section: Extended Ward Methodsmentioning

confidence: 99%

Development of an Equivalent Circuit of a Large Power System for Real-Time Security Assessment

Wijeweera

Annakkage

Zhang

et al. 2018

IEEE Trans. Power Syst.

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More and more system operators are interested in calculating transfer capability in realtime using real-time power flow models generated from the Energy Management System (EMS). However, compared to off-line study models, EMS models usually cover only a limited portion of the interconnected system. In most situations, it is not practical to extend the EMS model to capture the impact of the external systems and therefore using an equivalent network becomes necessary.The development of equivalent circuits to represent external areas was a topic discussed over the last 50 years. Almost all of these methods require impedance information about the external area to develop the equivalent circuit. Unfortunately utilities do not have the external impedance information in the real-time. Therefore, normal industry practice is to use off-line studies to develop an equivalent circuit and use that circuit in the real-time operation without any validation. This can result in errors in the security assessment. Therefore, power industry need a method to develop or validate an equivalent circuit based on the available real-time information. This thesis work is focussed on meeting that industry need.The work on this thesis presents two new methods that can be used to generate an equivalent circuit based on the boundary conditions. This method involves calculating equivalent impedance between two areas based on the boundary stations voltages, voltage angles and power leaving the boundary stations into external areas.This thesis uses power system simulation between two areas to change the system condition to obtain different boundary bus voltages, voltage angles and power injections to generate necessary data. Regression analysis and least square method is then used to generate the equivalent circuit using these data. It is expected that system changes will provide necessary information in the real-time to generate the equivalent circuit.The proposed methodology is validated with modified three area 300 bus system as well as using Manitoba Hydro's system. Contingency analysis, transfer level calculation and PV curves analysis is used to validate the proposed method. Simulation results show that the proposed method produces adequate accuracy in comparison with detailed off-line system models.The main advantage of the proposed method as compared to other existing methods such as Ward and REI is that the proposed method does not require external impedance information to generate the equivalent circuit. The ability to generate reasonably good equivalent circuit only using available boundary information will help utilities to generate or validate the equivalent circuit based on the current system conditions, which will intern help improve the accuracy of the security assessment.i Acknowledgments I would like to express my appreciation and sincere thanks to Udaya Annakkage, my research advisor, for his guidance, support and advice throughout this research. I was truly enriched by the many discussions we had over the course of thi...

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Section: Extended Ward Methodsmentioning

confidence: 99%

Development of an Equivalent Circuit of a Large Power System for Real-Time Security Assessment

Wijeweera

Annakkage

Zhang

et al. 2018

IEEE Trans. Power Syst.

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“…The existing equivalent methods including the Thevenin equivalent method, the traditional Ward equivalent method (Ward, 1974) and the extended Ward equivalent method (Monticelli et al,1979) were widely used. For this paper, the classical Ward equivalent was used.…”

Section: Network Reductionmentioning

confidence: 99%

“…Finally, the Ward equivalent method considers equivalent power injections at boundary buses (Monticelli et al, 1979), as shown in Equation (7).…”

Section: Network Reductionmentioning

confidence: 99%

Load area aggregation considering integration of electric vehicles to the system

Rodríguez-García¹,

Pérez-Londoño²,

Flórez³

2015

ing.inv.

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Current electric power systems have an increasing penetration of electric vehicles, and its effect has to be considered in different studies, such as optimal dispatch or voltage stability, among others. Additionally, considering that power system analysis becomes complex when the number of buses increase, this paper presents a methodology for aggregation of load areas that use a measurementbased load modeling approach based on an evolutionary computational technique and a classical reduction method. This aggregate load area model is proposed to reduce areas that consider electric vehicle (EV) load models. The proposed method provides a static equivalent load model and an equivalent network that can be used to reduce the computational effort required by power system studies. In order to validate the application of the proposed methodology, a 30-bus power system considering several disturbances and levels of penetration of the electric vehicles was used. The results show that the equivalent network model allows the reproduction of different events with an acceptable accuracy when it is compared to the original system behavior.Keywords: Reduction of power systems, measurement-based load modeling approach, electric vehicle, particle swarm optimization. RESUMENCon la inclusión de los vehículos eléctricos en las redes de energía es necesario analizar su impacto en los diferentes estudios, como el caso del despacho óptimo o análisis de estabilidad de tensión, entre otros. Debido a que el análisis de los sistemas de potencia se hace más complejo a medida que se incrementa el número de barras, en este artículo se presenta una metodología para la agregación de áreas de carga, que emplea el modelado de carga basado en mediciones, que a su vez se basa en una técnica computacional evolutiva y un método clásico de reducción. Se propone este modelo de agregación de área de carga con el fin de reducir áreas que contienen modelos de carga de vehículos eléctricos. El método propuesto provee un modelo equivalente estático de carga y de la red, que puede emplearse para reducir el tiempo computacional requerido para análisis específicos en la red. La metodología propuesta se valida en el sistema modificado IEEE de 30 barras, ante diferentes perturbaciones y diferentes niveles de penetración de los vehículos eléctricos. Los resultados muestran que el equivalente de red obtenido permite reproducir los diferentes eventos con una aceptable exactitud en comparación con el comportamiento del sistema original.Palabras clave: Reducción de sistemas de potencia, modelado de carga basado en mediciones, vehículo eléctrico, optimización por enjambre de partículas.

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“…Also, for situations in which there is no real-time observability of external networks, the use of external equivalents is necessary. Several effective methods to reduce networks and derive external equivalents have already been proposed (Monticelli et al 1979;Savulescu 1981). SDSA currently adopts the Ward method (Monticelli et al 1979) with flexibility to allow some of its variants.…”

Section: Network Size and Observabilitymentioning

confidence: 99%

Online Dynamic Security Assessment

Jardim¹

2014

Power Electronics and Power Systems

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This chapter describes an implementation of an online dynamic security assessment system based on time-domain simulation, in which dynamic models are the same as those used offline for planning studies with all necessary details. It contains a review of the adopted methods and algorithms (power flow, continuation power flow, time-domain simulation, energy functions, single machine equivalent, and Prony spectral decomposition) focusing on the main issues related to their numerical and computational performance. The utilization of these methods to execute complex security tasks such as dynamic contingency analysis and security region computations is described. Aspects of high-performance computation (fineand coarse-grain parallelization) are discussed. Some practical results obtained online and comparisons of online with offline planning cases are shown.

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Real-Time External Equivalents for Static Security Analysis

Cited by 126 publications

References 9 publications

Development of an Equivalent Circuit of a Large Power System for Real-Time Security Assessment

Development of an Equivalent Circuit of a Large Power System for Real-Time Security Assessment

Load area aggregation considering integration of electric vehicles to the system

Online Dynamic Security Assessment

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