Probabilistic Static Voltage Stability of Power System with Integration of PV Generators using Monte Carlo Simulations

As a renewable source, the uncertainties and intermittencies of solar irradiance have become the main concern in developing and integrating such power generation into an electricity network. In power system operation, it is important to maintain a stable voltage profile under random power injection from renewable power generations. The effect of photovoltaic (PV) power plants on the static voltage stability of the interconnected power system is presented in this paper. The probabilistic study was conducted through Monte Carlo Simulation (MCS) to investigate the fluctuation of voltage profiles under uncertain power injection from PV power plants. The standard test system of IEEE 14 bus and practical test system of Lombok, West Nusa Tenggara electricity network are investigated. It was noticed that the installation of a photovoltaic power plant affected the voltage profiles. The fluctuated condition of power injection from PV power plant resulted in more fluctuation of voltage profiles as indicated by higher standard deviation values. Moreover, distributed location of the PV power plant also influenced the circumstances of voltage fluctuation, providing less fluctuated condition of voltage profiles. Eventually, it can be observed that the voltage fluctuation would influence the static voltage stability of the interconnected power system.

Improvement of Static Voltage Stability of 16-Bus Bali System by Optimal Placement of SVC

In a power system, the reactive power imbalance is related to the stability of the static voltage because the injection of reactive power that the bus receives from the system determines the bus's capability in the system. Rapid increases in real and reactive power losses occur as the system approaches the voltage drop point or the maximum load point. It is necessary to support local and adequate reactive power to avoid system leading to be voltage collapse. This study analyzes the improvement of the margin of static voltage stability using one type of modern control equipment of shunt flexible AC transmission system (FACTS), namely the static var compensator (SVC). The controller's representations are used in the continuation power flow (CPF) process to study static voltage stability. The proposed method's effectiveness has been investigated using a practical test system, namely the Bali 16-bus system, to increase the system loading capacity. The simulation was carried out by installing a modern controller in the best location, namely on bus 07 ASARI; an increase in system margin loading closed to 2% compared to the base case condition, namely λmax = 1,879 p.u with the voltage profile not changing significantly.

Static Voltage Stability Assessment of the Kenyan Power Network

In recent years, the Kenyan Power Network has witnessed large growths in load demand. Although the increased load demand has somewhat been matched with an increase in transmission and generation capacity, the rate of expansion has not been matched with the rate of increase in load demand due to economic, environmental, and geographical constraints. This has led to the system being prone to instability since it is being operated under stressed conditions. In the recent past, several studies have been carried out on voltage stability analysis and improvement using various conventional methods. However, conventional methods have various limitations in their utilization for voltage stability analysis. One solution to overcome these limitations is to employ a combination of one or more methods so as to get more information and greater degree of accuracy in voltage stability studies. In this paper, a methodology is proposed involving the combination of QV modal analysis, sensitivity analysis (VQ) and power-voltage curves in assessing the static voltage stability analysis taking a case study of the Kenyan Power Network. V-Q sensitivity analysis and QV modal analysis have been used to identify the load regions most susceptible to voltage instability and the corresponding weak buses in the network for various V-Q responses. Reactive power loss sensitivities for branches in the network have been used to determine the critical (weak) lines in the network. Loading margins (LM) and voltage stability margins (VSM) have then been used to determine the proximity to voltage collapse of the voltage weak buses identified by QV modal analysis. The effect of tripping one the critical lines on the voltage weak buses is also investigated. The current high voltage power network under the average peak loading conditions during the year 2019 is considered for the study. The paper also reviews existing voltage stability analysis methods and their limitations.