The objective of this paper is to provide a comprehensive
analysis of earthing system to enhance protection system
performance in distribution networks. Al Ain Distribution
Company (AADC) is one of the subsidiary companies of Abu
Dhabi Water and Electricity Authority (ADWEA) in the
United Arab Emirates (UAE). AADC is responsible to
operate and maintain the power distribution from voltage
level of 0.4 kV up to and including 33 kV in the eastern
region of Abu Dhabi emirate. AADC is always keen to
provide safe and secure power supply to its customers.
Network performance KPI’s such as SAIFI, and SAIDI would
be improved, if protection system isolates the fault correctly.
The protection system can’t operate independently, if the
network components such as earthing system, equipments,
OHL/Cable, etc. are not designed properly. AADC initiated a
project in the year 2010 to study the existing earthing
arrangement and standards in liaison with protection system
to improve network performance. The study also included
live line tests in 11kV system with different types of fault
with different vendor in order to analyse performance of HiZ /
BCP relays as HiZ faults are a great challenge in AADC due
to nature of soil in eastern region of Abu Dhabi emirate. Trial
earthing was also a part of the study which included different
types of earthing grids in variant site conditions at different
locations to analyse the nature of soil in order to improve
earthing system in AADC network. AADC was the first
utility company in the region (UAE as well as Gulf countries)
to conduct the live line tests in 11 kV OHL. The test results
and trial earthing lead to several conclusion in determining
optimum earthing arrangements and selection of right
protection application in AADC network. Thus, the study
added additional advantage to improve protection system
performance in distribution network. This paper also analyses
the performance of multiple protection applications duly
considering power transformer neutral earthing arrangement
such as solid, resistor and reactor earthing, for safe and secure
operation in distribution network level.