Mathematical Model and Solution of Electric Network.- Load Flow Analysis.- Stochastic Security Analysis of Electrical Power Systems.- Power Flow Analysis in Market Environment.- HVDC and FACTS.- Mathematical Model of Synchronous Generator and Load.- Power System Transient Stability Analysis.- Small-Signal Stability Analysis of Power Systems.

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Modern Power Systems Analysis

This paper provides a comprehensive list of books, reports, workshops and technical papers related to voltage stability and security

Bibliography on voltage stability

The paper deals with the validity of various dynamic models of induction machines. The fifth-order Park model and various reduced-order models are used to predict the low-frequency dynamic response of a 15 kW induction machine, and the theoretical results are compared with an extensive series of measurements. Several transfer functions are investigated in the perturbation frequency region below 35 Hz using three types of basic excitations: perturbations in the shaft torque, supply voltage and supply frequency. The maximum perturbation frequency for an error less than 10% is used to study the validity range of the models; this range is evaluated for each model and transfer function, using the data of 31 different machines. The influence of the machine parameters and various physical phenomena is studied. The results show that a large number of transfer functions is needed for judging the general validity of a dynamic model.

Comparison of reduced-order dynamic models of induction machines

A method has been developed for preparing load models for power flow and stability. The load modeling (LOADMOD) computer software transforms data on load class mix, composition, and characteristics into the from required for commonly-used power flow and transient stability simulation programs. Typical default data have been developed for load composition and characteristics. This paper defines LOADMOD software and describes the dynamic and static load modeling techniques used in this software and results of initial testing for BAKHTAR power system.

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Load Modeling for Power Flow and Transient Stability Computer Studies at BAKHTAR Network

When wind power penetration is high, the available generation may be more than needed, especially for wind-powered microgrids working autonomously. Because the maximum peak power tracking algorithm may result in a supply-demand imbalance, an alternative algorithm is needed for load sharing. In this paper, a fully distributed control scheme is presented to coordinate the operations of multiple doubly-fed induction generators (DFIGs) in a microgrid. According to the proposed control strategy, each bus in a microgrid has an associated bus agent that may have two function modules. The global information discovery module discovers the total available wind generation and total demand. The load sharing control module calculates the generation reference of a DFIG. The consensus-based algorithm can guarantee convergence for microgrids of arbitrary topologies under various operating conditions. By controlling the utilization levels of DFIGs to a common value, the supply-demand balance can be maintained. In addition, the detrimental impact of inaccurate and outdated predictions of maximum wind power can be alleviated. The generated control references are tracked by coordinating converter controls and pitch angle control. Simulation results with a 5-DFIG microgrid demonstrate the effectiveness of the proposed control scheme.

Fully Distributed Coordination of Multiple DFIGs in a Microgrid for Load Sharing

Appropriate modelling of dynamic loads is of primary importance in voltage stability studies. The paper deals with the modelling of a load consisting of a static load plus an aggregate of induction motors. The behavior of three simplified models for such a load configuration is compared. The three models are (A) a generic nonlinear dynamic model of the first order as proposed by Karlsson and Hill, (B) a static exponential load plus a dynamic first-order model for the induction motors, and (C) a static exponential load plus a dynamic third-order model for the induction motors. A power system with a longitudinal structure is chosen as the case-study. It is shown that for the same perturbation (tripping of one of two high-voltage parallel lines) the simulation results are quite different from each other and, in certain cases, only the third-order dynamic model correctly predicts the voltage collapse phenomena at the load bus. An interpretation of the different behavior of the various models is given.

A. Mari

Papers

On dynamic load models for voltage stability studies