Power conditioner control and protection for distributed generators and storage

This paper describes an integrated control and protection scheme for the power conditioner used by the medium rating grid-connected distributed generators and storage devices. The proposed control scheme consists of two loops: a steady-state loop that achieves optimum harmonic output by selective elimination of low-order harmonics and a transient loop based on space vector methods that enhances the transient response of the generator and provides overcurrent protection and fault rejection. The paper presents simulation studies of a grid-connected storage device equipped with a controller based on the proposed scheme. The results of these studies demonstrate the robustness of the controller to varying line conditions and disturbances.     

Transient simulation of integrated AC/DC systems. I. Convertermodeling and simulation

A general and efficient method is presented for transient simulation of HVDC converters. The method utilizes a novel algorithm that is based on network topological concepts and provides an efficient solution to the problem of modeling the inherently nonlinear characteristics and time-varying topology of static power converters caused by the switching action of the thyristor valves. The application of the algorithm to a six-pulse converter unit results in an extremely flexible and efficient model that can be easily interfaced to both the AC and DC sides of an integrated AC/DC system     

Transient simulation of integrated AC/DC systems. II. Systemmodeling and simulation

For pt.I see ibid., vol.3, no.1, p.166-72 (1988). A flexible and computationally efficient method is presented for transient simulation of integrated AC/DC systems. The method is based on network topological concepts and utilizes the results presented in pt.I. A modular modeling approach is used that facilitates the application of the method to any AC/DC system configuration     

Finite-element models for open-air power lines in broadband PLC

This paper describes the application of finite elements for the modeling and simulation of overhead power-line structures in the high-frequency range, using existing computing tools and software. This paper treats specifically non-uniform wire arrangements common in overhead power networks, including line junctions, bends, neutral grounding, etc., which disturb the transmission of signals, especially at high frequencies, increasing reflections, radiation, and mode conversion. The proposed models could be used in applications associated with broadband communication over power lines providing a reliable representation for assessing the capability of the overhead network to carry high-frequency signals and estimate the resulting electromagnetic emissions.     

A gradient-based algorithm for the state initialization of controlsystems

The authors present an efficient algorithm for the state variable initialization of the network and control system. This algorithm is suitable for slow transient studies in AC/DC systems. It uses gradient methods to update the integrator inputs. The network is solved by the load-flow and the control system by the Gauss-Seidel method. Following the simultaneous steady-state solutions of the combined network and control system, the initial values of the state variables describing the dynamics for each component are calculated. A computer program was developed on the basis of the proposed algorithm for the initialization of slow transient studies in AC/DC systems. Results from the initialization of a typical AC/DC system are given     

Application independent interactive environment for power systemseducation

The authors present an interactive software package for the simulation of power system stability studies. The package is intended as a supplementary tool for the teaching of power system stability courses at the graduate level. The development of the package was done exclusively for IBM-PC and compatible computers. The hardware mainly requires VGA display and 640 kbyte of memory. Professional libraries used for the development of the package include Meta Windows, graphics Menu, and Object Professional. The authors describe the methods used for the integration of various analysis programs and the organization of the data and information pertinent to a system study