Real-time fiber optic network for an integrated digital protection and control system

The authors present a real-time network using an optical-fiber transmission line and implement the prototype network system for a proposed integrated digital protection and control system. A single network structure is investigated which supports both protection and control functions. It realizes high-speed communications among the power equipment. As a communication protocol the IEEE 802.4 token passing bus protocol with fiber-optic medium is employed, taking substation environments into account. Two implementation schemes for the communication scheme are suggested which are based on the IEEE 802.4 specifications. An allocation method is presented for setting the network parameter and some performance indices are analyzed. Through the experiments, it is shown that the proposed prototype network system satisfies the necessary requirements in substations