Delivering key power system study to enhance grid reliability for Saudi Energy

Tractebel has successfully completed a power system study for Saudi Energy, aimed at strengthening the reliability and security of the Kingdom of Saudi Arabia’s Extra High Voltage (EHV) transmission network.

Addressing a Critical Challenge in the EHV Network

The power system study provides Saudi Energy with valuable insights to support a more resilient and secure electricity supply across the country. This was the first time SEC commissioned a study of this depth with focus on the settings of the synchro check relays.

Tractebel’s contribution

As part of the assignment, Tractebel delivered:

• A comprehensive technical report supporting Saudi Energy in refining the circuit breaker reclosing practices
• In‑depth analysis, leveraging extensive expertise in high‑voltage systems
• An advanced power system study using electromagnetic transient (EMT) simulation tools, specialized software used to model fast and complex electrical behaviours in the grid

Scope and objective of the study

Tractebel was tasked with analyzing whether the maximum permissible voltage phase angle difference for reclosing EHV circuits in the Kingdom’s grid can be optimized without risking equipment or compromising system security.

What is maximum permissible voltage phase angle difference? Before a circuit breaker closes, the two sides must have their voltages “lined up,” meaning they rise and fall at almost the same time. If the difference between them (the phase angle) is too great, then the breaker would be connecting two voltages that are not in sync. This can cause an electrical stress to the system, torsional stress on the generator’s shaft, or trigger an instability, especially in the presence of renewable energy power converters. The challenge is to determine the optimal phase angle difference so that the impact of the circuit breaker operation is limited.

Under Saudi Energy’s standard operating practices, synchro check relays use a default setting for both automatic and manual reclosing. However, due to increased phase angle observed in some practical cases, Saudi Energy commissioned a dedicated study to better understand and optimize the limit when appropriate.

By completing this study, Tractebel provided Saudi Energy with:

• A recommended phase angle limit that balances operational flexibility and system safety
• Insights into the conditions under which higher angle differences remain acceptable
• A robust technical basis to support future reclosing strategies across the grid

Through detailed modelling and scenario analysis, Tractebel ensured that all recommendations align with Saudi Energy and international operational practices and standards.

Strengthening Saudi Arabia’s Grid for the Future

With this project now finalized, Saudi Energy is equipped with clear, technically validated recommendations to improve reclosing operations across its EHV network. The study supports the Kingdom’s ongoing efforts to reinforce energy infrastructure and ensure a reliable electricity supply for communities, businesses, and critical sectors nationwide.