Optimal management of power networks using a dynamic line rating approach

Abstract

Due  to  the stochastic  nature  of  wind,  the  wind power integration into the power system poses serious challenges to  the transmissionsystem  operators(TSO).  The  impact  of large amounts  of windenergygeneration onto  the  power  system  may congest  some  of  the transmissionlines  that  transport  it  to  the (sometimes)distant consumption centres. Since the occurrence of wind not  only  contributes  to  the  loading  of theconnecting electric  line,  but also  increases  the  line  capacity,  via  convective cooling  of  the  cables,  a dynamic line rating  (DLR)analysis computes a more realistic set of values for the line capacity,thusit can be a cost-effective solution toalleviatesomeoverhead line congestion problems.This work presentsan  operational  tool  for  the  DLR  analysis  of power networks,allowingthe optimal  integration  of  renewable energy sources,especially wherepotentially congested linesmay exist.  The  tool  was appliedto  a  real  case  studyusing  forecast meteorological  data,  and the results achieved were  compared with  those  obtained  by using the  Portuguese TSOmethodfor assessingthe  transmission  capacity  of  the  lines. For  high  wind speed   conditions,results  show anoticeable  increase   on  the cable’s convective cooling assessed by the DLR analysis. This assessmentleadsto a noticeable rise on the cables’capacitiesthat overcame the congestion associated with the high injection levels of wind power generationin the power grid.