Siemens has been awarded an order to supply two mobile substations to National Grid SA, the transmission operator of Saudi Electricity Co. Based on the unique specifications from National Grid SA, Siemens has combined its existing mobile substation modules together to design and manufacture two 380kV mobile substations able to fit and suit in any network area of the kingdom. With a rating of 502 MVA each, these two high-voltage mobile substations will be the most powerful ever built in a single feeder configuration, according to Siemens. A mobile substation is mounted on a special trailer and can easily be transported wherever needed.
Thanks to their built-in rotating air bushings, their installation and connection time is reduced to less than one week and can be executed with no equipment manufacturer services. Mobile substations are a fast and versatile solution for emergency power restoration or fast-track grid connection that also guarantees the utmost reliability. They also support heavy maintenance or renovation work as an interim bypass substation that can be easily set up to reduce or eliminate power outages.
With a voltage of 380 kV and a power capacity of up to 502 MVA, the two substations are the most powerful ever built on a single feeder configuration. One substation contains three single-phase autotransformers with a capacity of 167.3 MVA each, which makes them the largest transformers for mobile substations ever built at Siemens.
“The National Grid SA-Specified mobile substations configuration jointly customized with Siemens, will allow us to bypass any 380 kV substation in the event of failure or major maintenance work,” said Ali S. Al-Rammah, Vice President of National Grid SA and head of the company’s maintenance business line. “They can also be used as fast-track solutions to connect a new plant to the grid. It has been essential to develop a customized technical specification for us to have a plug-and-play solution that we could quickly mobilize and install on our own. It will significantly improve the 380-kV and 132-kV grid resiliency that are the backbone of our power transmission infrastructure.”
Siemens’ portable power solutions come fully preconfigured and tested as plug-and-play substations that can be connected to the grid by overhead line or insulated cables. The modules contain all the necessary components for a complete substation: power transformers, GIS switchgears, MV/HV cable drums, protection and control systems, and auxiliary power supplies. They are available in several modular configurations to meet each customer’s needs. One of the core components of the substation is the transformer, which is very efficient as well as extremely compact designed in order to meet the dimension requirement of the mobile substation. This is proof that the Siemens grid resilience concept is a real first aid kit for emergency and bypass situations. Another core component is the switchgear, which need to combine the challenge of being entirely pre-assembled for easy installation and also able to withstand the mechanical stresses of transportation. This is made possible by the Siemens design and engineering of the gas-insulated switchgear and the supporting trailer as a single system.
The Saudi Arabian economy is growing, as is its demand for reliable power. On January 17, 2017, Khalid Al-Falih, Saudi Arabian Minister of Energy, Industry, and Mineral Resources, described the nation’s program for promoting renewable energy and emphasized that the Kingdom seeks to produce 9.5 gigawatts of renewable energy in 2023. This will also challenge the country’s grid and pave the way for flexible solutions like pre-fabricated portable substations. Siemens has delivered more than 100 high-voltage mobile substations up to 420 kV worldwide.