hi,
I am unable to get exact idea about to calculate the L index of voltage stability. please help me..or upload matlab code to calculate L index method
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Voltage stability is a major concern in the planning and operation of power systems. It is well-known that voltage instability and collapse have led to major system failures, with the development of energy markets, more and more electric companies are faced with the stability of tension imposing limits. The problem of voltage stability can be explained simply as the inability of power to provide reactive power or excessive consumption of reactive power by the system itself. It is understood as a reactive power problem and is also a dynamic phenomenon. The objective of this work is to develop a fast and simple method, which can be applied in the power system in line, to estimate the voltage stability range of the power system. In general, the analysis of the voltage stability problem of a given power system must cover the examination of these aspects:
Or how close is the system to voltage instability or collapse?
O When does voltage instability occur?
O Where are the vulnerabilities of the system?
O What are the main contributing factors?
O What areas are involved?
Analysis of voltage stability often requires examination of many system states and many contingency scenarios. For this reason, the approach based on steady-state analysis is more feasible, and can also provide insights into voltage reactive power problems. Several special algorithms have been proposed in the literature for voltage stability analysis using static approximation ; however, these approaches are laborious and do not provide useful sensitivity information in a dynamic process. Voltage stability is indeed a dynamic phenomenon. Some utilities use Q-V curves in some load busses to determine the proximity to voltage instability . A problem with the Q-V curve method is that by focusing on a small number of buses, the problem of system-wide voltage stability will not be easily unraveled. An approach, model analysis of modified Jacobian matrix load flow, has been used as static stability index to determine the vulnerability of the low stability bus problem .
This article explores the on-line monitoring index of voltage stability, which is derived from the basic static power flow and Kirchoff's law. A referral will be given. The voltage stability index predicts the voltage problem of the system with sufficient precision. This voltage stability index can work well in the static state as well as during the dynamic process. It can also be used to find the vulnerabilities of the system, the margin of stability based on the point of collapse and the key factors for the problem of voltage stability, etc....