e-Diagnostics of the Switchgear Equipment Using IEC 61850

Abstract

The   proposed   implementation   of   e-diagnostics   of   switchgear   equipment   aims   to   improve   the reliability indicators of the equipment and to reduce the costs of its exploitation. As far as fundamental diagnostics problems are concerned  it  is  still essential to develop  methods of  calculating tests   and   diagnostic   procedures,   which   are   a   base   for   an inference  on  the  reliability  state  of  the  object.  Generally  it  is done   based   on   symptoms   (characteristic   for   non-stationary acting  object),  which  additionally  expose  processes  of  aging and wear, or based on  functional model of a discrete object.  At  the  present,  in  many  cases  the  digital  part  of  IEDs  is  tested by application of a response function compression method. This method    characterizes    with    relatively    small    control    test effectiveness  and  it  does  not  enable  subordinating  the  tests results to the specific node of the IEC 61850 standard. The  paper  introduces  diagnostics  of  the  digital  part  of  IED’s.  It presents a certain inference engine on which one of  the elements of  the   digital  circuit  is  (with   determined  probability)  in  the inoperable state,  if  for any  pin, (of  some  element)  a  fail  result  of the  functional  test  has been  observed.  That conclusion  is  reached by applying the probability approach and knowledge of the digital circuit   information   net,   being   a   certain   digraph   respectively described.  The  method  of    determining  the  important  causal-effectual  relation  between  the  determined  inoperable  state  of  the circuit  element  and  the  fail  result  observed  on  some  pins  of  the other element, using the information net of the circuit is presented. Thereafter  we  provide  some  remarks  on  how  to  build  the  IED digital part functional testing, which may be executed under the command e.g. sent from the data concentrator.