BC Hydro sought to improve its ability to respond to a potential abnormal loading condition with high consequences, at one of its hydroelectric facilities. An excessive transient penstock pressure surge following a failure of the generating unit’s pressure regulating valve, could lead to severe penstock structural damage, equipment failure, and prolonged downtime. To address this, BC Hydro initiated a project and contracted Klohn Crippen Berger (KCB) to develop an innovative pressure relief solution. The primary component is the Pressure Relief Port (PRP), engineered to safeguard against extreme overpressures.

The PRPs are uniquely designed with an extremely narrow activation pressure range, a feature that enhances their effectiveness but also demands an exceptional level of precision. Premature activation could cause unnecessary system disruptions or environmental impacts, while failure to activate within the precise pressure range could lead to structural failures. This challenge required rigorous engineering analysis, extensive transient modeling, and a comprehensive testing program to validate the PRPs’ performance under real-world conditions.

A key focus of the testing program was ensuring that the PRPs would activate reliably within their designated pressure range under high-pressure, transient conditions. The relief ports were subjected to simulated operating scenarios in a specialized lab’s testing facility (Powertech Labs) to verify activation at the correct thresholds. Advanced instrumentation was used to monitor various parameters; each test result was carefully analyzed to confirm compliance with strict operational tolerances. The results demonstrated that the PRPs activated within the required activation pressure range.

With the successful completion of the design validation, the PRPs were installed, and have been fully operational since December 2024. This upgrade enhances the facility’s resilience to a penstock pressure surge failure.

The project integrated advanced design, in-depth analysis, and rigorous testing to achieve BC Hydro’s operational and safety objectives. The design phase involved detailed transient modeling to simulate hydraulic pressure fluctuations and to predict potential overpressure scenarios. These simulations guided the optimization of the design.

A critical aspect of the approach was the structured design development, stringent quality assurance/quality control for fabrication and installation, and a testing program for both PRPs and their activation monitoring system. The testing process incorporated static and dynamic assessments to evaluate performance within the narrow activation pressure range. Real-world operating conditions were simulated using high-pressure burst and cable severing test trials to confirm activation reliability under governing scenarios.

Collaboration played a key role in the project’s success, with KCB working closely alongside BC Hydro, Powertech Labs, and the fabrication and installation contractors. Fabrication and installation were subject to stringent quality control with multiple levels of oversight. The testing methodology adhered to strict protocols, with detailed instrumentation capturing activation pressures and response times to validate performance within required tolerances.

This structured and collaborative approach allowed the project to successfully achieve its critical milestones.

BC Hydro’s Penstock Pressure Relief Ports project addressed a potential abnormal loading condition that could result in excessive hydraulic transient pressures. KCB designed and implemented Pressure Relief Ports (PRPs) to protect against overpressures, preventing structural damage and equipment failure. The system was successfully tested and installed, then completed in December 2024. The PRPs enhance system resilience. This facility, newly equipped with PRPs, demonstrates industry innovation.