The Dynamic of Synchronous Generator under Unbalanced Steady State Operation: A Case of Virtual Generator Laboratory

The purpose of this study is to design and develop a synchronous generator virtual laboratory for undergraduate student courses, which can be treated as an accessorial tool for enhancing instruction. Firstly, the study reviews the general concept and algorithm of synchronous generator model. Secondly, the simulation method of this system is discussed. Finally, the paper introduces its example and analysis. One of the major objectives of this project is the dynamics of synchronous generators connected to the 500 kV EHV Jamali (Jawa-Madura-Bali) System under unbalanced steady state condition that could be modeled as a balanced synchronous generator’s model with unbalanced voltage inputs. The balanced synchronous generator model based on the rotor’s qd0 reference frame was chosen to substitute generator’s model embeded in loadflow analysis. The verification of the proposed generator’s model was checked by comparing it with a PSS Tecquiment NE9070 simulator. The unbalanced voltage inputs of generator were derived utilizing the loadflow analysis by determining the phase and sequence currents, and average bus voltages of the 500 kV EHV Jamali grid considering unbalanced portion variations. Meanwhile, the load locations having significant effect on the test generators are obtained by using the electricity tracing method. The developed virtual laboratory with a given example demonstrated the usefulness of the tool for studying synchronous generator under unbalanced steady-state operation

Comparison performance study of singly-fed and doubly-fed induction generators-based bond-graph wind turbines model

This paper consecrates to a comparative performance study of singly-fed and doubly-fed of induction generators thrusted by wind power turbine of similar generation capacity of 2.5 kW, and constant or variably wind speed. The singly-fed induction generator model could be represented using natural reference frame and doubly-fed induction generator model is described using a Park reference frame. Because of several physical domains existing in both induction generators like mechanical and electrical, modeling of generators is difficult, therefore the modeling based on physical methods takes a high credibility under these conditions. Among the procedures is Bond-graph method that models the systems based on law of mass conservation and/or law of energy conservation containing in the systems. Modeling the parts of both singly-fed and double-fed induction generators are based on Bond-graph method. We found that the impact of stator coil winding for on the current is in the form of changes of its value and steady state intervals; increasing the number of stator coil windings may also lead to increased stator current and the longer their steady state interval. Our study demonstrates also that doubly-fed induction generator possesses advantages compared to singly-fed induction generator, namely better current quality output and an adaptation to fluctuating wind speeds. The performance study is done in constant and variably wind speeds using simulated results of 20-Sim software