It is important information for the Transmission System Operators that how safe the current system state is and if the hardiness and fault-tolerant capability against changes in given operating conditions is appropriate or not.
They need very accurate information about the transmission system’s current security status to predict the weakening of the system’s condition and the appearance of problems, and to respond to these problems in the shortest time possible and start the transmission system’s restoration.
Today’s practice defines the electric power system’s security based on two types of sources: the fulfilment of N-1 criterion (analysis of fulfilment of the criterion in snapshots of current network status or in planned network condition) and the real time security of the network condition (continuous monitoring of loadability and voltage limits). Beyond these indicators, the phase-angle difference of voltage-phasors between the ends of transmission lines also can provide information about the security of transmission system.
In my thesis, I discuss the indicators which characterize and affect the safety of power transmission, with them I analyse the security of own created power transmission models, and finally I evaluate the test results.