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This paper presents an investigation into the impact that plug-in hybrid electric vehicles (PHEVs) could have to mitigate the effects of fault-delayed voltage recovery. The energy storage and conversion system in PHEVs, given potentially high levels of future market penetration, represent a sizable dispersed energy storage resource or reactive power source that electric utilities could leverage to...
This paper presents the nonlinear, time-domain model of a saturable-core inductor. The model is capable of accommodating high-order nonlinearities by representing the current-flux characteristic of the inductor by an analytical (closed form) polynomial function of high degree. An automated procedure is developed to transform the highly nonlinear model to a fully-equivalent quadratic model, without...
This paper provides a methodology to extract the dynamic real time model of an electric power system using phasor measurement unit (PMU) data (GPS-synchronized) and other SCADA data that are available in substations. In addition to typical voltage and current measurements, PMU data include frequency and rate of change of frequency. Such data are available in raw form, as time-stamped instantaneous...
This paper describes a laboratory setup as the scaled model of a three substation power system. The scaled model has been developed at the Power System Control and Automation Laboratory of Georgia Institute of Technology. Elaborate physical models for the power system components along with high fidelity models for signal generation and interfacing to the laboratory setup are among its unique features...
This paper elaborates on a newly introduced approach for time-domain transient simulation of electric power systems with highly nonlinear and/or switching subsystems. The new methodology is based on a numerical integration scheme that assumes that the system model states vary quadratically within a time step (quadratic integration). The proposed method is an implicit integration scheme which demonstrates...
This paper discusses distribution feeder related voltage recovery phenomena following typical faults in a power distribution system, considering the existence of dynamic loads. Such loads consist mainly of induction motors. A three-phase, physically based power system model is utilized, allowing inclusion of system asymmetries and imbalances, typically encountered in distribution systems. The proposed...
This paper presents a laboratory setup for transient testing of relays and GPS-synchronized devices. The setup relies on a unique, realistic scaled model of a small three substation system, along with its metering equipment. Lumped models of transmission lines are included that realistically represent the mutual couplings between the phases and asymmetries. Two phase shifters provide loading controllability...
This paper discusses voltage recovery phenomena following typical faults in a power system considering the existence of dynamic loads, consisting mainly of induction motors. A three-phase, physically based power system model is utilized, allowing inclusion of system asymmetries and imbalances. The proposed modeling and simulation is based on a quadratic power system model and on a numerical integration...
This paper proposes a comprehensive approach for bulk power system reliability assessment. Specifically, a framework of security-constrained adequacy evaluation (SCAE) based on analytical techniques is developed to assess the ability of a bulk power system to supply electric load while satisfying security constraints. This approach encompasses three main steps: (a) critical contingency selection,...
This paper concentrates on the implementation of an analytically-based identification procedure of three phase induction motor models, for steady-state and quasi-steady-state analysis. The mathematical model of the motor is based on the use of linear and quadratic equations, reducing therefore the system nonlinearity to at most second degree. The model optionally includes slip-dependent rotor parameters,...
This paper describes the implementation of a three- phase, phase-domain induction motor model for asymmetric load flow and quasi-steady state analysis. The mathematical model is based on the use of linear and quadratic equations, reducing therefore the system nonlinearity to at most second degree. The model optionally includes slip-dependent rotor parameters, allowing therefore a unified and accurate...
A framework of security-constrained adequacy evaluation (SCAE) based on analytical techniques is proposed to assess the ability of a bulk power system to supply electric load while satisfying security constraints. It encompasses three main steps: (a) critical contingency selection, (b) effects analysis, and (c) reliability index computation. Effects analysis is the most essential but computationally...
Contingency simulation is an essential but computationally demanding procedure for power system security assessment, reliability evaluation, and real time operation. Simulation methods based on the traditional power flow (TPF) model usually suffer from lack of the realistic system model and slow convergence. To solve such problems, this paper proposes a contingency simulation methodology based on...
This paper addresses the impact of load dynamics, and in particular induction motor loads, on voltage recovery after disturbances. The paper proposes a methodology that is based on load flow techniques with advanced modeling capabilities, augmented by a simplified induction motor dynamic model. The objective is to realistically capture the dynamic characteristics of voltage recovery phenomena, avoiding,...
This paper discusses voltage stability and voltage recovery phenomena following typical faults on a power system. A modeling approach is proposed that combines the efficiency of power flow techniques and capabilities of transient stability models. The proposed methodology is based on a quadratic model of the electric power system, including generators and dynamic loads consisting mainly of induction...
Relatively poor performance of state estimators is a well documented experience. Yet, control and operation of electric power system requires reliable state estimators. The poor performance is attributed to implementation simplifications that use single phase asynchronous measurements and the positive sequence model of the system. These simplifications have generated practical problems. The experience...
Speed governors are key elements in the dynamic performance of electric power systems. Therefore, accurate governor models are of great importance in simulating and investigating the power system transient phenomena. Model parameters of such devices are, however, usually unavailable or inaccurate, especially when old generators are involved. Most methods for speed governor parameter estimation are...
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