High-voltage substations

Solutions and services for the entire life cycle

You expect comprehensive expertise in power transmission, technology leadership, long-standing experience from utility and industry projects around the world, and reliable financial strength? Then Siemens Energy is your partner of choice for high-voltage substations on budget and on time. 

Much more than you would expect

Siemens Energy's scope of supply comprises much more than the high-voltage equipment that is required for the operation of a substation. It includes high- and medium-voltage switchgear, transformers, and equipment as well as all ancillary systems for control, protection, communication, and condition monitoring.

Siemens Energy provides the entire range of services, technologies, and components that are required for the successful construction and operation of a high-voltage substation of any type. It is up to you to select from a comprehensive range of available services:   

  • Concept, planning, engineering
  • Project execution including project management and manufacturing of all key components
  • Commissioning
  • Service and maintenance, refurbishments, upgrades, dismantling of old equipment
  • Financing

Siemens Energy helps industry customers focus on their core business by supplying fast, reliable, complete solutions that are based on a high degree of flexibility, continuous development, and outstanding consulting expertise for all steps of a high-voltage substation project: 

  • Concept, planning, engineering
  • Support in grid code compliance as well as in handling and processing official planning documents and approval procedures
  • Project execution including project management and manufacturing of all key components
  • Commissioning
  • Service and maintenance, refurbishments, upgrades, and dismantling of old equipment 
  • Financing

Types of high-voltage substations

The various types of switchgear that are available for high-voltage substations make it possible to provide flexible, individual solutions. Here’s an overview of the different kinds of high-voltage substations and their main advantages. 

Reliable, proven, cost-efficient

Substations with air-insulated switchgear

Siemens Energy high-voltage substations with air-insulated switchgear (AIS) are the cost-efficient choice for rated voltages of up to 800 kV. They are renowned for highest reliability, economical operation, and low maintenance requirements. 

The Siemens Energy experts always consider the electrical parameters as well as the environmental conditions to which a substation is exposed. That’s why Siemens Energy AIS substations meet even the most demanding challenges and provide:

  • an optimum solution when space restrictions and environmental circumstances are not an issue
  • easy implementation of a wide range of standard applications
  • reliable switching for up to 800 kV, rated currents of up to 8,000 A, and short-circuit currents of up to 80 kA

Compact, powerful, adaptable

Substations with gas-insulated switchgear

Siemens Energy high-voltage substations with gas-insulated switchgear (GIS) are ideally suited to meet some of today’s most important requirements: bringing power on high-voltage levels right into the centers of urban areas. With almost 50 years of GIS manufacturing experience and the largest installed base of GIS, Siemens Energy is able to provide GIS solutions that even comprise operational training. 

More than 34,500  Siemens Energy GIS bays are currently in operation in GIS substations all over the world – even in most challenging environments. The comprehensive range of GIS for rated voltages from 72.5 kV to 550 kV provides ideal solutions for indoor and outdoor switching applications up to the highest performance rates that require:

  • a small footprint
  • outstanding reliability
  • very low noise and electromagnetic emissions

More information

Gas-insulated switchgear

Modular, versatile, clever

Mixed technologies substations

Mixed technologies substations – or hybrid substations – are mainly used for the refurbishment and expansion of substations with air-insulated outdoor and indoor switchgear, particularly in cases when such modifications need to be accomplished with the substation in service. As space and time are main cost factors in the expansion of substations, solutions with Siemens Energy highly integrated switchgear (HIS) provide the possibility to quickly adapt a substation to today’s demands. The space-saving HIS circuit breakers, disconnectors, grounding switches, and instrument transformers are housed in pressure-resistant, gastight enclosures and require no additional space. Busbars and bushings originate in conventional AIS technology.

Mixed technologies substations are:

  • ideally suited for new substations when space is limited
  • outstandingly compact thanks to the hybridization of GIS and AIS technology
  • clearly structured, with good access to all equipment
  • modular to suit virtually any network concept

Flexible, robust, plug and play

Prefabricated power solutions increase grid development agility and resilience

Siemens Energy's prefabricated power solutions are an ideal plug and play solution when it comes to achieving urgent grid connection, renovation, or expansion in challenging environments. Their mobile and modular design allows to take up the challenge of tight construction timeframes, natural disasters, and operational restrictions. They ensure maximum flexibility of design and utilization, excellent reliability, and a high return on investment thanks to:

  • fast installation, small footprint, and easy relocation
  • minimum interface management, full pre-commissioning prior to dispatch, and little on-site work
  • robustness to transportation and handling constraints, as well as harsh environments

High-voltage substations in practice

Reliable nodes in power systems around the world

  • 75 Approx. years of experience
  • 100+ Countries worldwide
  • 8,000+ Projects in total

Comprehensive expertise and many decades of practical experience are at the heart of all Siemens Energy AIS and GIS high-voltage substations. They serve even the highest voltage levels and are used in the most demanding environments.

The largest GIS in North America increases electric system reliability and reinforces New Jersey’s transmission backbone

Public Service Electric and Gas Company SE&G | Bergen substation, USA   This project broke records in terms of scale and performance. Gas-insulated single-pole bus ducts with a total length of 2,700 meters connect the GIS accommodated in the 85-meter-long switchgear building with the air-insulated part of the substation. The 245 kV breakers were the world’s first of its kind to switch a short-circuit current of 80 kA. The project included engineering, design, supply and delivery, commissioning, all associated control and protection equipment, and buildings for the substation. This projects upgraded the existing 138 kV lines to 230 kilovolts. The GIS helps provide additional load capacity and enhances safety and reliability by redundancy in the system design and earthquake resistance.

Norway benefits from an additional feed-in of electricity provided by wind and small hydro power plants

Statnett SF energy system operator | Sogndal substation, Norway  Sogndal substation is a key node point in Western Norway. It strengthens the Western Norway power grid, increases the electricity transmission capacity, and provides voltage support by installation of a Static Var Compensator (SVC). As a result, it ensures an additional feed-in of electricity and a redundancy capacity provided by wind and small hydro power plants. Siemens Energy was responsible for the planning, delivery, and installation of nine bays for a 420 kV AIS, in  double bus, two breaker design, three bays for a 145 kV AIS, in single bus, single breaker design. Furthermore the contract was comprising the connection of the existing 300 kV transmission lines with the new 420 kV substation and the design, delivery, and installation of a +/- 250 MVAr Static Var Compensator (SVC).

Technical excellence at your fingertips

Siemens Energy high-voltage substations incorporate the strong performance of one of the world’s leading engineering companies and supplier of power transmission products, solutions, and services. If you want to learn more about the advantages of Siemens Energy's time-tested, proven solutions and to delve into all technical details, simply contact the Siemens Energy Customer Support Center and have your individual questions answered directly by our experts.