1. A method for detecting a power plant equipment overheating or fire event, comprising: placing in a power plant pluralities of first and second types of overheating detectors, for respectively monitoring first and second different ambient physical parameters that are indicative of power plant equipment overheating or fire; providing an overheating detection processing system, coupled to the pluralities of first and second types of detectors, for receiving output sample readings from all of the detectors, and coupled to at least one information storage device; causing the processing system to: sample remotely in real time all of the detectors that are actively monitoring power plant equipment; store in the information storage device at least one output sample reading from each detector; determine in real time a likelihood of whether a combination of stored sample reading levels from both of the first and second detector types identifies an ambient physical parameter combination of a power plant equipment overheating or fire event, by performing the following in any order: referencing previously stored association information in the information storage device that associates respective separate types of detector sample temporal reading levels and trends, or combinations of types thereof, with previously known equipment overheating or fire temporal reading level trends of ambient physical parameters; separately comparing at least one stored sample reading level from at least one detector of each respective type of overheating detector with respective stored association information relevant thereto that includes historical trend information, to determine respective separate first overheating confidence levels, for each type of detector, that the power plant is actually experiencing an equipment overheating or fire event; comparing a combination of the at least one stored sample reading from both types of overheating detectors with respective stored association information relevant thereto that includes historical trend information, if such combination stored information is available, to determine at least one second overheating confidence level that the power plant is actually experiencing an equipment overheating or fire event; and combining all previously determined confidence levels information to derive an overall confidence level of whether the power plant equipment is experiencing an actual overheating or fire event.