Innovation in Global Power - Parsons Brinckerhoff

Transporting Power Across the Grid
http://www.pbworld.com/news_events/publications/network/
Rehabilitation and Reconstruction of Abu Dhabi
Transmission Network By M.R. Jayasimha, Abu Dhabi, 971 50 4554907, jayasimhaM@pbworld.com
The author tells how PB is
assisting Abu Dhabi Water
and Electricity Authority
to further enhance the
reliability of the emirate’s
transmission and distribution
network. He focuses on
a modification to the
switchgear and replacement
of power transformers and
a substation.
Abu Dhabi’s electricity transmission network was established in the early 1970s at mainly
220 kV and 132 kV levels. Since then, the country’s rapid rates of growth and development
and characteristic high increases in load demand have led to an expansion of the network and
upgrading to 400 kV. In addition, the Abu Dhabi Water and Electricity Authority (ADWEA)
initiated a repair and rehabilitation project in 1999 to further enhance the reliability of the
existing power transmission and distribution network. 1
PB was selected as consultant for this important and technically complicated project. Once
we completed the first phase of the project by 2002, we were awarded an extension for the
second phase, which included new substations and a new scope of services for the rehabilitation
and replacement of existing switchgear in transmission substations.
Starting in January 2003, seven construction contracts worth US $70 million were awarded.
These contracts included:
• Single to double bus bar modification of 13 2kV gas insulated switchgear (GIS) in five substations
• Replacement of ten 132/11 kV 40 MVA power transformers
• Replacement of the existing 132 kV substation in the Taweelah Power Station Complex. 2
Single to Double Bus Bar Modification
The single to double bus bar modification of 132 kV GIS in five energised substations
was a very specific and demanding task. The GIS in these substations was already in
service for up to twenty years. The modification works required partial and in some
cases complete shutdowns of the substation. The works were planned during the
winter season because during the summer in Abu Dhabi maximum system demand
occurs due to the high air conditioning loads. In one of the substations, the bus bar
protection was replaced with numerical low impedance busbar protection during the
modification works. In the other four substations, existing low impedance busbar
protection was adapted for double bus bar type switchgear. Of the three types of
switchgear to be modified, manufacturers had discontinued production of two of them.
The busbar and isolator modules required for this modification were manufactured
specifically for this purpose by the original equipment manufacturers. Figure 1 shows
the switchgear before and after the modification.
Replacement of Power Transformers
Figure 1: W59 substation before single to
double bar modification of 132kV GIS (top)
and after (bottom).
For the replacement of ten ageing 132 kV/11 kV 40 MVA power transformers, the
design of the new power transformers was adopted to suit the existing transformer
compound dimensions and the length of the existing high voltage cables. The
opportunity was taken to also replace the transformer protection relays with latest
numerical protection relays. In one of the GIS substations, a bus reactor bay was
modified to provide a fourth 40MVA transformer. Ten new 11 kV feeders were also
provided in this substation to receive power from the newly installed transformer.
Existing 132 kV cables were reused providing new terminations at the transformer end,
(page 67)
1 For more information about Abu Dhabi Water and Electricity Authority’s (ADWEA’s) introduction of control systems in its transmission substations and PB’s involvement in this
work, please read “Experiences and Trends in Automating Transmission Substations in Abu Dhabi” by Oleg Matic in PB Network’s 20th Anniversary issue (Issue 66), pp. 88-89. or
on the the Web at http://www.pbworld.com/news_events/publications/network/issue_66/pdf/66_37_Matic_ExperiencesAndTrends.pdf
Another of ADEWA’s projects to augment Abu Dhabi’s electricity supply is covered in “400 kV Interconnection of Abu Dhabi Island” by Walter Bullock, PB Network Issue 65,
pp.79-80 or on the Web at http://www.pbworld.com/news_events/publications/network/Issue_65/pdf/079.pdf
2 For information about the use of a PB invention that cut fuel consumption at the Taweelah complex, see “How Innovation Can Open Market Opportunities” by Paul M. Willson,
PB Network Issue 63, pp 71-72 and on the Web at http://www.pbworld.com/news_events/publications/network/issue_63/63_26_willson_howinnovationcanopen.asp
PB Network #68 / August 2008 62