Distance protection under extreme conditions

The phenomenon this paper looks at is power swings, voltage collapse, series compensation and the effect of shunt active VAR compensation. Power swing blocking although a well established technique in its own right; is hampered by traditional detection methods which can be compromised when the system topology changes. Voltage collapse (insufficient VARS) and its effect on distance protection is not a subject which has had wide spread discussion. Fast and slow VAR compensation devices like SVC´s and STATCOM bring in new challenges to this traditional art. Series compensation is also being considered on relatively short lines in order to export more power through existing corridors and has implications on distance reach as well as directionality.