Strategies to Refurbish or Maintain Control Command System of Substation of Electrical Network

Technology of control command system (or instrumentation and control I&C equipment) has evolved dramatically during last 30 years from electromechanical relay, analog relay to digital relay. Then utilities have to maintain different type of devices. Risks linked to this fact are ageing effect on protection relays and technical life time of piece of equipment. After 20 years of use, manufacturers stop the process of fabrication of devices, then spare parts will diminished what could increase repair time after failures and maintenance cost, and could lead to problem for the power supply of customers. EDF R&D then is studying since 2006, different strategies in the next years in order to find the best scenario to arbitrate between renewal or maintain control command system at the optimal cost, while taking into account consequences on power quality supply, and keep enough stock of spare parts. This paper will present the way to classify control command system which has to be renewal firstly. Also old control command could be used as spares parts for old generation of control command system, and new contract could be define with manufacturers to maintain old piece of equipment or to make new pieces of equipment as the older one. Methodology to elaborate indicators to follow each year ageing effect of control command system of stations will be also presented in this paper.