An innovative special protection system involving long distance actions

The general criterium adopted by the Brazilian System Operator for the calculation of the Transfer Capability is (n-1). However, the Brazilian Grid Code establishes that multiple simultaneous outages should be considered as a single contingency when statistics demonstrate that they are likely to occur, with important consequences to the bulk power system, in the following cases: · When circuits share the same transmission towers · When distinct transmission lines run in the same right-of-way In case of scheduled disconnection of transmission elements, thermal generation dispatching or Special Protection Systems may be implemented in order to increase Transfer Capability, depending on the severity of the consequences of credible contingencies. Another important aspect of the Brazilian Interconnected Power System (BIPS) is related to its predominantly hydro electrical characteristic, formed by basins with complementary hydrological regimens, favoring large energy transfers in order to optimize the energetic resources of the system. Due to these characteristics, should a limitation exist in the Transfer Capability among subsystems, Special Protection Systems (SPS) are utilized to overcome the transfer constraints.