A comparative study in improvement of voltage security in a multi-bus power system using STATCOM and SVC

In this paper an effort is made to assess local and global voltage security of multi-bus power system in presence of STATCOM and SVC. A Global Voltage Security Indicator (GVSI) derived from series network equivalent of multi-bus power system has been employed to assess overall system voltage security. Thevenin´s equivalent of the power system with respect to a particular load bus has been used to assess the local voltage security. A comparative study on effectiveness of STATCOM and SVC in improvement of voltage security using network equivalents has also been presented and validated using the well known L-index. STATCOM found to be more effective than SVC to ensure voltage security and at the same time it is also capable to reduce reactive power line loss considerably.