Characteristics Of Synchronous Machines Research Articles

Operation Constraints and Methodology for Stability Preservation in Power Systems with High Penetration of Non-Synchronous Generation

Nowadays, significant changes in the electricity generation mix raise questions about the secure operation of power systems. Most of the newly installed generation capacity is being connected to the grid via power electronic converters, thus can be seen as a non-synchronous generation. The theory of power system operation and control relies heavily on the characteristics of synchronous machines and conventional network structure. Therefore, the effective integration process of the new technologies must include the composition of new physical models for converter dominated large power systems as well as innovative solutions to ensure the secure operation in the future. The focus of this paper is a holistic analysis of the reducing power system inertia to frame up new constraints for system operators through simulation studies on the Institute of Electrical and Electronics Engineers standard 118 bus test system. The different system states and scenarios offer a comparison opportunity between stability preservation possibilities. Minimum inertia constraint calculation methodologies and various objective functions are being discussed. The utilization and effects of synthetic inertia from non-synchronous generators and energy storage systems is also considered to quantify the exact effects.

Identification techniques of functions approximating magnetization characteristics of synchronous machines

PurposeThe aim of the paper is to present the approximation methods of the magnetizing characteristics of the salient pole synchronous machines with the fundamental MMF harmonics.Design/methodology/approachThe energy based approach is used to formulate a set of the functions approximating the magnetic flux linkages versus an equivalent magnetizing current in the circuit model of the synchronous machine. The estimation of the approximation functions parameters is based on the results of the field calculations.FindingsThe identification of the approximation functions is effective and significantly simpler on the basis of the magnetic field co‐energy function, than on the basis of the magnetic flux linkages.Research limitations/implicationsThe magnetic field co‐energy function determined by FEM is sufficient for simplified calculations of the magnetic parameters occurring in the circuit models of the electrical machines with nonlinear core.Practical implicationsThe paper provides guidance for the circuit modelling of the multi‐pole generators and motors under conditions of magnetic saturation.Originality/valueA paper has succeeded in determining the internal magnetic characteristics of the synchronous machine with a salient pole rotor.

Large system interaction characteristics of superconducting generators

Differences between superconducting generators and conventional machines are identified, and ways in which superconducting machines will offer both advantages and problems are shown. Superconducting generators will have system interaction characteristics, somewhat different from those of their conventional counterparts. In general, superconducting machines will improve characteristics of the power system; their low reactances and long time constants will improve transient stability and voltage regulation. However, these also produce large fault currents and torques. If care is not taken, these machines may product interesting and perhaps destructive resonant effects on shaft lines. The author builds simple models that allow several important system integration characteristics of synchronous machines, including the differences between conventional and superconducting machines, to be discussed and understood. These include reactive power capability, transient stability, damping, voltage control, fault currents, and torques. >

整流器付同期機の特性

整流器付同期機の特性

Torque-Angle Characteristics of Synchronous Machines Following System Disturbances

A method of predetermining the torque-angle characteristic of a synchronous machine following a system disturbance is of importance in calculating the transient stability limit and in evaluating the effect on this limit of additional rotor circuits or of a change in excitation. In the first part of this paper equations are derived which are of sufficient generality to evaluate such factors. Two types of system disturbances are considered: 1. Switching in or out of a connecting line, 2. Occurrence of a balanced three-phase system fault. In the second part, an actual case of switching out a connecting line is calculated and the results compared with field tests taken on the New York Power and Light Corporation's system. No attempt has been made to draw any general conclusions as to the effect of amortisseurs or changes in excitation. A subsequent paper will present results which have been obtained from the application of the method presented in this paper.