Small Signal Stability Analysis of Grid Connected Photovoltaic

Abstract

This paper primarily focuses on the small signal stability analysis of a power system integrated with solar photovoltaics (PV) IntroductionThis paper represents small signal stability analysis of grid connected photovoltaic. The study involves the investigation in terms of eigenvalue analysis, damped frequency, damping ratio and participation factor for increased solar PV penetration and load variation into the grid. The results obtained would indicate the impact of solar PV penetration on the small signal stability of the power system.In this modern era, consumption and depletion of the world's fossil fuels have been expanding at an alarming exponential rate. The average 500 MW coal plant annually produces 3.7 million tons of cardon dioxide and other greenhouse gases [1]. This has caused a worrisome issue on greenhouse effects, global warming and even energy shortage in the coming years ahead.Therefore, there is an accelerating need to look for sustainable energy resources such as renewable energy to ensure a sustainable future [2]. Power systems that are dominated by synchronous generators are highly nonlinear and may experience a change in its dynamics and operational characteristics when connected to renewable energy resources. A study done in [3] shows that the integration of wind DFIG-based wind turbine generators into the power system grid does indeed impact the overall performance of the system in terms of small signal stability. Furthermore, another study [4] reaffirms that wind penetration to the grid causes small signal stability problems. The results in [4] showed a dynamically unstable behavior and altered local and inter-area mode shapes.On the contrary, a study was done on the small stability effects of distributed solar PV and DFIG based wind generation on the grid. It was found that the stability margin of the system is enhanced considerably [5]. Based on [6], penetration of DFIG wind turbines of almost 2MW in a wind farm shows an improvement in the of the power system stability when aggregated under certain conditions on a small grid. Based on [7], integration of wind energy into the power system improves stability by reducing the settling and overshoot time under the action of power system stabilizers. Renewable energy in the distribution level was studied in [8] and it is observed that the dynamics of the wind generator contribute significant system oscillations whereas solar PV generators actually enhances the small signal stability characteristics of the system whereby the eigen sensitivity decreases. As the renewable generation was increased, frequency of modes had an increase whereas the damping ratio was relatively constant. It was also found that there were no negative effects on the increase in renewable generation [9]. Furthermore, another study found that when a PSS equipped wind farm penetration increases, the damping ratio of inter-area modes improves [10]. Based on [11], solar PV and wind energy

Rooftop Solar PV Penetration Impacts on Distribution Network and Further Growth Factors—A Comprehensive Review

“…Small signal stability indicates the constant skill of network systems to sustain a steady voltage of the system after exposure to minor interference caused by minor changes in loads and power [99]. In another definition, it is stated that small disturbances of small signal stability result from low-frequency oscillations in power systems ranging from 0.2 Hz to 2 Hz [100].…”

Reactive power control of solar photovoltaic inverters for grid code compliance support

“…The integration of a PV generator in the medium voltage distribution network has a positive technical impact as indicated by its ability to balance active and reactive power flows, reduce voltage drops, and decrease power losses in distribution network [1], [2]. However, the integration of large-scale PV generator into medium-voltage network has a negative impact on power quality as indicated by harmonics, voltage flicker, voltage sag, frequency variation, voltage unbalance, and small signal stability [3], [4]. Another problem is the fault current contributed by the photovoltaic power plants (PVPPs) connected to the distribution network which can cause malfunctions in the protection devices [5], [6].…”