Transient stability considering dynamic load in bulk power system with high DG penetration

Abstract

SUMMARYTransient stability may be seriously affected when a large number of distributed generators (DG) stop simultaneously during voltage sag. It is necessary to analyze accurately the dynamics of bulk power systems with high DG penetration. In this paper, transient stability is studied by analyzing power-angle curves of generators while considering load dynamics and model order reduction at lower voltages. Based on the analysis, a decrease in the load internal resistance after voltage sag causes transient instability of generators. The phenomenon is confirmed through simulation using a one-machine and one-load model. This paper also suggests that the simulation results might be misled by traditional bulk power system modeling such as using the static load model and ignoring impedance at lower voltages. As for the numerical simulation, a large level of DG stoppage leads to transient step out in a bulk power system, and the stability is greatly improved by DG voltage regulation.

Experimental evaluation of DG's dynamic voltage support capability improving short‐term voltage stability on power system loads

“…The experimental results given in this paper support the simulation results [3][4][5] obtained by us in a large-scale system. We believe that the DGs to be introduced next (in particular inverter-linked DGs) should be equipped with the LVRT function and DVS function.…”

“…(1), then the control was performed by Eq. (3), which has been presented in prior papers [3][4][5]. Here, W represents the rated output (kW): Table 2.…”

“…Given this situation, as the introduction of distributed generators (DG) advances, the shortterm voltage stability [1][2][3] of the load may worsen, and the effects on the upper voltage level of the grid cannot be ignored. We have previously shown that instability of the short-term voltage in the load [3] and generator desynchronization [4,5] may occur as a result of voltage sag caused by grid faults. We have also shown through simulations that if dynamic voltage support (DVS) equipment in which a DG maintains the voltage dynamically is set up as a countermeasure, these instabilities can be corrected.…”

PV Power Output Control Improving Transient Stability of Power System with a Large Penetration of PV

“…Here, we use P-δ curves of one-machine one-load infinite bus model to evaluate the effects of IM rate and PV output on transient stability [9][10][11].…”

Impact of Postfault Active Power Recovery of Photovoltaic Power Generation on Transient Stability

“…Previous research on PV interconnection in terms of transient stability analysis shows that results are affected by PV and load models used in simulations as well as operating conditions of synchronous generators and other factors [3][4][5][6]. However, load and PV modeling are not always adequate, and step-out conditions are not always clear.…”