Overview

As renewable penetration increases in power systems around the world, utilities are required to proactively investigate the security and reliability of their systems to accommodate the new generation. A North American utility needed to address stakeholder interests in adopting more renewable generation and retiring conventional generation while maintaining system stability.

Challenge

The utility needed a consultant to determine the level of renewable energy that could be accommodated by the existing system and help them present a sound investment approach that addressed stakeholder interests without putting the power system at risk.

Solution

PSC ran a comparative study between the client’s system model and jurisdictions in South Australia and Ireland experiencing similarly increased levels of renewable penetration in their systems. Our detailed knowledge of those systems from like projects expedited the analysis and ultimately reduced the study effort for the client. We shared lessons learned from how these jurisdictions responded to the retiring of conventional (synchronous) generation and the adoption of more renewable generation as well as what other system settings were adjusted in order to accommodate them.

In addition to calculating the regulation reserves needed to compensate for renewable energy intermittency, and the short circuit levels at wind farm points of interconnection (POI), PSC performed several dynamic simulations on the system model to check the transient stability of the system in the face of severe events.

Results

Because the client’s power system is on an island, connection to the mainland is critical to the stability of their system. If the AC ties connecting the power system to the mainland fail, it can result in a major imbalance on the island. During the study, PSC learned that an event several years prior had caused the existing AC tie to fail. Losing this tie put system stability at risk. As a result, PSC recommended the client build a second AC tie to mitigate the risk of islanding the system.

Ultimately, the effort culminated with a series of recommendations for system reinforcements that would help the client proceed safely and responsibly with the increased adoption of renewable generation.