Dynamic Voltage Stability Comparison of Thermal and Wind Power Generation with Different Static and Dynamic Load Models

Abstract

This paper presents a static and dynamic voltage stability analysis of a power network with thermal and wind generation considering static and dynamic load models. The thermal plant was modeled as a synchronous machine and the wind farm as a variable speed induction generator based on a doubly-fed induction generator. The load considered the ZIP, exponential recovery, induction motor, and frequency-dependent load models. The bifurcation points were found by continuation power flow and sensitivity analyses. In addition, dynamic voltage stability assessments were performed considering changes in the moment of inertia and the frequency parameters. All simulations were carried out in a 4-bus power system and using the power system analysis toolbox (PSAT) and MATLAB script code. The results show that the thermal generator had difficulties to maintain stability under dynamic load variations and frequency changes, the wind generator had difficulties to maintain voltage for the load with induction motors, and both generators had difficulties when the moment of inertia is increased.

The transient stability analysis of wind turbines interconected to grid under fault

“…The same simulation will be carried out for the two case studies to visualize the generation of reactive energy by the fixed and variable generators. During a sudden fault, the generation of the reactive does not result from a mechanical force but results from a pure electric injection [31]. This transient analysis describes the impact of the DFIG reactive injection on the stability of the rotor angle of the synchronous generators.…”

Fractal representation of the power demand based on topological properties of julia sets

“…The process begins by reading the typical load demand records of real and reactive defined for a 24-hour period as shown in Table 1 [19,20]. The per unit values of the power demand are calculated with the following expression: per unit power = actual power / base power.…”

Voltage collapse point evaluation considering the load dependence in a power system stability problem

“…Contingencies scenarios showed that the phenomenon can also affect the steady state operation of all interconnected systems, for that reason they have become one of the issues most addressed in power system researches [1][2][3][4][5][6]. One of the most important topics of scientific research on voltage stability problem considers indices to predict the occurrence of voltage collapse [7][8][9][10]. These indices can be used in utilities to determine the closeness of the collapse voltage point, and is focused on establish a scalar magnitude that can be monitored when power system parameters change [11,12].…”