Channel Components Transform (CCT) is a recently developed technique to decouple interconnected power networks. This paper aims to further explore the CCT and extend its applications. Methods and algorithms are proposed to extend its application in identifying the critical generators and branches of a network from the voltage stability perspective. The proposed methods are verified by case studies conducted on multiple test systems. This paper also demonstrates the capability of the CCT to work properly when a limited number of phasor measurement units are available. For this purpose, a strategy is proposed to determine the number and location of PMU installations that are sufficient to track the modes of voltage collapse and associated critical components. The proposed allocation strategy is examined through case studies of an actual power system.