Keeping one of Europe’s most important power transmission grids stable and secure

The Swiss power transmission grid is not the biggest in Europe, but it is one of the most important.

Not only does the grid supply electricity to the country’s thriving economy with eight million people it also exchanges large quantities of power daily with neighboring France, Germany, Italy and Austria at over 40 interconnection points.

Swissgrid is responsible for operating and maintaining the 6,700 km-long Swiss transmission network. The system has 121 substations and 12,000 transmission towers. In 2016 a total of 73,775 GWh of energy was transported. Most importantly, like all transmission system operators, Swissgrid’s priority is to ensure the grid operates with 100 percent reliability.

Balancing supply and demand

One of Swissgrid’s most important tools to ensure energy security is an ABB grid controller, which balances the amount of energy produced and consumed and keeps the grid frequency stable at a constant 50 hertz.

This is not as simple as it sounds. Vast amounts of energy flow through, into and out of the grid every second. If half the country switches the coffee machine on at the same time, or if a power plant fails, an imbalance between production and consumption of electrical power occurs instantly. This causes the frequency to rise or fall and it could result in damage of large electrical machines. Even some clocks might run faster or slower if they synchronize their time to the grid frequency – as many public clocks e.g. at train stations still do.

For more than 25 years the ABB grid controller performed its duties reliably. But the time came to modernize it and ABB undertook the project and successfully delivered a state-of-the-art system early this year. The complexity of the project implied an enormous challenge for the seamless integration of all systems and applications into the existing Swissgrid architecture. In addition to the Swissgrid in-house systems, a large number of external systems had to be connected, and their data had to be entered and synchronized.

Using various ABB AbilityTM automation technologies, the newly provided solution exploits the full potential of digitalization, raising grid operations to a new level.

Impressive features

Many of the solution’s features are impressive:

  • Electricity flows across all border power lines are measured at one second intervals using four different measurement sources for each line to ensure accuracy. Using these and other data, the grid controller calculates each second the amount of power needed and instructs power generators to adapt production accordingly to maintain frequency stability;
  • The solution is integrated and harmonized in a cyber-secure way with vast amounts of software in Swissgrid’s process and business systems to ensure safe and seamless operation;
  • Redundancy is vital: If a system component fails due to damage or malfunction, a redundant component takes over immediately. Some critical parts even have quadruple redundancy. All data points are mirrored and all systems monitor each other; and
  • Crucially, the operators really like the new grid control interface, as all relevant data can be easily and intuitively accessed. This makes it easier for them to make timely and correct decisions and do their jobs efficiently.

100% availability

Swissgrid project manager Heiko Beck expressed his company’s requirements clearly: “As this project concerns the security of the energy supply in Switzerland, 99% availability of the grid controller is not enough. We must have the highest possible availability!”

From November 2016 to January 2017, the new ABB grid controller ran successfully in parallel with the existing one. It passed the test of 100 percent  availability and continues to run the Swiss transmission grid failure-free.

Read more about the solution and Swissgrid’s appreciation of it here.

Follow the grid frequency in real time to see how the grid controller is performing.



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