Voltage and angle stability monitoring: possible approaches in the framework of a framework of a wide area measurement system (WAMS)

One major item of TERNA Defence Plan consists in the realisation of a Wide Area Measurement System (WAMS), equipped with Phasor Measurement Units (PMU), to provide advanced monitoring tools and facilities. A decisive aspect of WAMS project is the development of monitoring functions for effective support to the operator, especially against system dynamics possibly leading to large blackouts. The effectiveness of wide area technology in monitoring and preventive control of those kinds of disturbances is a matter primary interest in the framework of WAMS applications [1].
Some preliminary studies were carried out by TERNA and CESI in 2004 and 2005 with the aim of define the most suitable monitoring facilities within the Italian power system. Theoretical studies addressed the most effective techniques for:
small signal stability monitoring,centralized event detection,detection of islanding scenarios,voltage stability analysis .
In the framework of WAMS project, TERNA and CESI started in 2006 the implementation of a small signal stability monitoring algorithm and of a voltage collapse detection facility. Those monitoring functions are currently completing their testing stage and are ready for being adopted as on line dynamic security assessment tools, at TERNA’s National Control Centre in Rome.

[1] Working Group 601 of Study Committee C4, “Wide Area Monitoring And Control For Transmission Capability Enhancement”, (Final Report, January, 2007).

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