دانلود Transient Analysis of Mechanically Switched Capacitors with and without Damping Network Connected to A.C Grid

Abstract

Mechanically  switched  capacitors  (MSC)  are  very  well known reactive power compensation devices which are extensively in use in power transmission systems. However, during switching of  MSC in a high voltage grid, significant transients  are  found  to  appear  across  the  capacitor  bank  bus  as  well  as  different  elements  of  MSC  which  may  lead  to  insulation  degradation affecting the long term performance of the capacitor banks.  An  improved  version  of  the  MSC  is  MSCDN  where  a  damping network is employed  with the capacitor banks to  damp out  the  transient  oscillations.  However,  during  switching  of  a  MSCDN plant significant transients are observed across its different elements. Considering the afore-said fact, in this contribution,  a comparative study of transient behavior of mechanically switched capacitors with and without damping network  is  presented  during  switching  in  a  400  kV  A.C  grid.  Transient simulations  are  performed  on  an exemplary MSC and MSCDN model using  PSCAD/EMTDC  software.  It  has been observed that there is a significant reduction in transient overvoltage  and  inrush  current  in  switching  a  MSCDN  plant  when compared to a mere MSC switching. Moreover, the percentage reduction in transient overvoltage and inrush current during  switching  a  MSCDN  plant  is  found  to  depend  on  the design  of  damping  network  which  may  be  important  to  analyze the  transient  behavior  during  switching  in  a  high  voltage  A.C grid.