Adaptive Overpower Protection Prevents Overheating In Power Distribution Networks

Focus:

In real applications a short-circuit resistance is not zero ohms, as assumed in theory. For a low-voltage dc power distribution network (PDN) with electronically limited current capacity, a comparatively large fault resistance may be considered the most critical: at high power ratings, it may be not low enough to activate the high-power source protection. As a result, hazardous energy will be dissipated in a typically small fault area. This article describes a technique to prevent hazardous conditions in low-voltage high dc power distribution networks. It begins by explaining how the short circuit resistance required to trip an overpower protection (OPP) circuit depends on the PDN voltage level and useful load idle and maximum power ratings, and why this can lead to hazardous conditions that do not trip the OPP. Then the article describes a protection circuit that adjusts the OPP threshold based on the power level consumed by a useful electric load at any given time. Simulations and experimental results are presented to verify circuit performance and compare it with that of a fixed OPP threshold.

What you’ll learn:

• How to understand the limitations of the conventional overpower protection method in protecting low-voltage dc power distribution networks
• How to implement an adaptive overpower protection method that adjusts the trip threshold in real time based on power consumption of the load

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Author & Publication:

Viktor Vogman, Power Conversion Consulting, Olympia, Washington, How2Power Today, Aug 16 2018

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