An early warning and security countermeasure (EWSC) system for electric power control centers

An early warning and security countermeasure (EWSC) system for electric power control centers is proposed in this paper. Taking advantage of real-time data from SCADA system in a control center, this system automatically tracks operation state of the electric power system, ranks and screens contingencies, determines security levels of current system and finally gives corresponding countermeasures according to the security levels. Being integrated into current EMS, this system determines the power transmission limits on tie lines or flow gates by an on-line steady state security and stability analysis. Combing on-line digital simulation of transient stability analysis with EMS, weakness of current power system is detected and noticed to the dispatchers so as for them to take further actions to enhance security level of the power system. Some preventive countermeasures to relieve insecurity of the system are given to improve security operation of the power system. This EWSC system alarms system emergency defined on the basis of steady state and dynamic state, issues a report to help dispatchers to take an action to relieve the emergency, and in some special cases, once acknowledged, sends a control command directly down to the power plants or substations for further generator tripping or load shedding. N-M outages caused by cascading faults are simulated by real-time tracking the sequence of events. By using real site data gathered from SCADA system, the functions of this system have been tested and some prospective results have been obtained