INTRODUCTION

The Transmission and Distribution systems over a period of time have grown complex as well as have become highly demanding. Due to large proliferation and also mix up of linear and nonlinear loads, the systems are continuously stretched to switching on and off of passive and active control devices, such as capacitor banks (APFC or TSC or TCR), or harmonic filter banks for correction of reactive power / power factor and / or load current harmonics. These economical methods have been further improved to direct on line correction with the use of STATCOM(N) / Active Filters / Unified power controllers etc. The most important aspects of a power system (T&D) are to (i) deliver quality power without interruption, (ii), use the switchgear and associated components within rated capacities, (iii) limit the voltage current transients within limits so that life of all connected components and system improves, (iv) apply all necessary protections to achieve improved life and reduce stresses on the connected equipment(s), and (v) retain its objective of simplicity in operation, highest possible reliability, almost nil maintenance, and highly economical.

It may appear that such a vast coverage of various associated aspects and objective(s) may be difficult to achieve. This paper perhaps is an attempt to get into possibly a new outlook or at least look at what can be done in such a situation. The paper first deals with reduction of voltage in stresses on protective breakers when applied in an MV substation and then analyses how to reduce transient voltages / currents in a relevant capacitor switching system.

DOWNLOAD RESOURCES