An Event-Based Nonintrusive Load Monitoring Approach: Using the Simplified Viterbi Algorithm

Nonintrusive load monitoring technologies are gaining popularity for their low energy monitoring costs. In the article, the authors present a simple event-detection algorithm based on maximum and minimum points. Then, they use a variant of hidden Markov model as the appliance model and combine it with event detection to reduce the input. Specifically, they propose a simplified Viterbi algorithm, which considers fewer state transitions each time than the traditional Viterbi. The experiment results show that their work can achieve higher than 90 percent accuracy for most high-power devices and 60–80 percent accuracy for most low-power devices. Meanwhile, the computational complexity could be much lower than with the traditional Viterbi algorithm.