Issue
The advantages and disadvantages of using an optical point sensor and a fiber loop sensor for arc flash protection.
Product Line
VAMP 221/321 Protection Relays
Environment
Arc Flash Protection Relays
Cause
Optimization of an arc flash protection solution by specifying either optical point or fiber loop sensors.
Resolution
Figure 1
Figure 2
Fiber loop sensor technology offers the following advantages when compared to the point sensor:
- Significantly reduces the cost of installation. A single optical fiber sensor can be as long as 200 feet, typically covering the same protection zone associated with conventional bus-differential protection but at a much lower cost than point sensors as shown in Figure 2.
- The loop approach eliminates any concerns about shadows from internal structures that might block the direct exposure to an arc flash.
- Optical point sensors are installed in every enclosed compartment and has a wired coverage area as shown in Figure 1.
- If the fiber sensor is configured in a loop, it can provide regular self-checking of the sensor’s integrity and continuity, producing an alarm if a problem is detected.
