Analysis of Power Grid Voltage Stability with High Penetration of Solar PV Systems
ABSTARCT :
Grid integration of solar photovoltaic (PV) systems has been escalating in recent years, with two main motivations: reducing greenhouse gas emission and minimizing energy cost. However, the intermittent nature of solar PV generated power can significantly affect the grid voltage stability. Therefore, intermittent solar PV power generation and uncertainties associated with load demand are required to be accounted to gain a holistic understanding on power grid voltage stability with high penetration of PV energy sources. This paper presents a framework for power grid voltage stability analysis considering uncertainties associated with PV power generation and load demand using Monte Carlo simulation. Commonly used voltage stability indicators such as critical eigen value, line loss, reactive power have been considered in the proposed framework. The proposed methodology has been verified by analysing voltage stability of IEEE 14 bus test system, with high penetration of PV energy sources and considering uncertainties associated with load demand. The results provide a clear insight to voltage stability of power grid with different penetration level of PV energy sources into the power grid.
EXISTING SYSTEM :
? The characteristics of microgrids are completely different from traditional power transmission systems, and as such, many of the traditional VSIs are obsolete for analyzing the voltage stability of microgrids.
? However, the majority of the existing VSIs can easily be modified by considering DERs in either the sending or receiving end of a two-bus circuit representing a part of a microgrid. This network is used to determine the indices.
? Margin residue is introduced in this strategy to avoid any damage in the inverter due to the over current flow more than the maximum current.Voltage stability within acceptable limits can also be assured through proper design and implementation of ICs in an islanded hybrid MG.
DISADVANTAGE :
? There may be different factors leading to various forms of disturbances resulting in voltage instability problems.
? System dynamics that influence voltage stability are usually slow. Therefore, voltage stability analysis can be done by using some selected static operating conditions of the power system.
? The static analysis techniques can highlight the nature of the problem related to voltage stability and identify the key contributing factors.
? The power flow problem for islanded microgrids can be defined by a set of time-domain nonlinear equations, which can be solved as an unconstrained minimization problem
PROPOSED SYSTEM :
• In order to overcome the issues originating from such high penetration scenarios, controllers that coordinate the response of conventional and alternative generators have been proposed, and the use of fast-responding storage systems is presented in as a measure to compensate the loss of inertia in the system.
• The study is performed on a test power system, proposed in , and comprises both its small-signal stability and its response to large disturbances affecting its frequency stability in a short range of time for which solar radiation can be considered constant.
• The final active power variation is proportional to the frequency deviation and decreases when the penetration rises regardless of the type of controller.
ADVANTAGE :
? There is a linear reduction in the magnitude of the reference output voltage of a DG with the increase in the injection of its reactive power.
? Thus, DGs with steeper Q-V droop slopes may present poor dynamic performance especially in the presence of non-linear loads.
? The stability performance of voltage source inverters under dual-mode operation was then investigated.
? In , a study was carried out on the static voltage stability impact of solar photovoltaic generation (SPVG) on power networks using P–V and V–Q curves to investigate the renewable energy generator model performance suitability.
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