Abstract:
When renewable energy sources are integrated into the existing power system, then they
act as a bridge between the electricity demand and supply, in a sustainable and greener
way. But this grid integration poses certain challenges for the power system operator.
In this work various issues, which are faced,are addressed. A typical IEEE 13 bus is
used to simulate the microgrid environment. Among the various protection issues, high
impedance fault(HIF) is addressed here. A high impedance fault(HIF) occurs whenever
a conductor gets broken and touches ground or when a line comes in contact of a semi-
insulating surface. Due to very small fault current, these faults are left undetected
by conventional overcurrent relays. In this work, a technique based on Mathematical
Morphology is implemented. Another technique based on the variation of 3rd and 5th
harmonic current components is implemented. The fault direction is estimated using the
fundamental apparent power. An anti-islanding detection technique, which discriminates
between islanding and other events such as capacitor switching, load switching, based
on positive sequence current and voltage components is proposed in this work. Another
protection issue, which is considered here, is protection system blinding and sympathetic
tripping. An adaptive protection scheme, based on the determination of optimal relay
settings is implemented. A 5-bus system is simulated for this.
All simulations are carried out in real time(RSCAD) using real time digital simula-
tor(RTDS).
