Siemens improves resilience of Saudi Arabian power grid with mobile substations

Siemens has been awarded an order to supply two mobile substations to National Grid SA, the transmission operator of Saudi Electricity Company. Based on the unique specifications from National Grid SA, Siemens has combined its existing innovative mobile substation modules to design and manufacture two 380kV mobile substations that are able to fit and suit in any network area of the Kingdom. With a rating of 502 megavolt amperes (MVA) each, these two high-voltage mobile substations will be the most powerful ever built in a single feeder configuration. A mobile substation is mounted on a special trailer and can easily be transported where 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 easily be set up to reduce or eliminate power outages.

“We are pleased that our mobile substations will provide our customer, National Grid SA, with three crucial aspects of a safe power supply: agility for grid reinforcement projects, grid resilience to failures and flexibility in operation, maintenance and renovation,” says Mirko Düsel, CEO of the Transmission Solutions Business Unit at Siemens Energy Management.

With a voltage of 380 kilovolts (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,” states Mr. 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 resilience 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.

Saudi Arabia’s Vision 2030 defines an ambitious growth path to address, among others, the rising demand for energy. On January 17th, 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 by 2023. This will 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.

Siemens will improve resilience of the Saudi Arabian power grid with mobile substations

Tied together, they form a mobile substation: Six trailers contain all the necessary equipment like switchgear and transformers. The substations’ bushings are rotative so they enable fast installation – less than one week – and maximum compactness in transportation mode.