TWIP® Level Switch in a Hydroelectric Dam – Reliable Technology Case Study

Aug 7, 2023
3 min read

Updated: Aug 10

A hydroelectric dam in the Southeast US, initially built to produce hydropower, now also assists in regulating water flow and water temperature for other plants downstream.

The Problem

The plant had outdated switches protecting lake water cooling equipment - dial gages mounted on the wall. Plant personnel were having a hard time reading the switches, leading to reliability and accuracy issues.

What the Ideal Water Detection Device Needed to Do

The ideal water detection device had to fulfill multiple objectives simultaneously. Foremost, false alarms were unacceptable - a system that trips when it shouldn't erodes operator trust and can trigger unnecessary shutdowns or interventions. Equally undesired was the cost and nuisance of routine testing just to assure proper equipment performance. For these reasons, plant personnel decided to upgrade to a TWIP® (Turbine Water Induction Protection) Level Switch.

What TWIP Is and Why the Name Matters

TWIP stands for Turbine Water Induction Protection - a naming convention that reflects the technology's origin in protecting hydroelectric turbines from water induction issues, even though its application extends to broader water detection needs like this dam's cooling equipment protection. The TWIP System combines the industry's most successful sensing probes with a choice of versatile, high-technology equipment options. TWIP systems of proven reliability and accuracy are easily tailored for strategic location within any individual steam plant.

Redundant Probe Placement

As an option, two trip probes can be installed vertically in the water detector at the same level, or trip point. This ensures that even with voting logic circuitry in place, the trip point remains consistent at a single, reliable level - removing ambiguity about exactly when the system should respond.

Voting Logic: Eliminating False Trips

The utmost in performance is achieved in TWIP Systems using the optional Voting Logic trip circuit. This employs circuit logic in which any 2 of 3 designated probes must detect water before the trip circuit activates. Voting Logic virtually eliminates false trip probes or a single level control failure from triggering an unnecessary response.

This is the direct answer to the "false alarms are unacceptable" requirement stated at the outset. Rather than relying on a single sensing point that could fail or misread, requiring agreement among multiple probes means a single faulty reading can't trigger the system on its own - genuine water presence is required across a majority of the probes before the trip activates.

The Result

The hydroelectric dam now has the reliability, accuracy, ease of reading, and modern technology plant personnel were looking for - replacing hard-to-read dial gages with a system engineered specifically to avoid both false alarms and the maintenance burden of frequent testing.

Why This Matters Beyond Hydroelectric Applications

While this case study is specific to a hydroelectric dam's cooling water protection, the underlying reliability principle - using redundant, voting-logic sensing to eliminate both false trips and single-point failures - applies to any application where a level switch protects critical equipment and unnecessary trips carry real operational cost.

Applications

TWIP Level Switch technology and voting logic principles are valuable for:

Hydroelectric & Power Generation: Cooling water and turbine protection systems
Any Critical Equipment Protection: Where false alarms carry real operational or safety cost
Facilities Seeking to Reduce Routine Testing Burden: Through inherently more reliable sensing rather than frequent manual verification