The Visual Analysis page is a novel attempt at doing relative performance analysis -- relative to an installation's ideal DC performance parameters. This visual analysis page can be a valuable tool for tracking performance history, and can provide some intuitive explanation for under-performance if it should exist.
We take the IV-and Power curves for a solar module, and modify them to depict IV and Power characteristics of an entire array, interacting with an inverter. A mathematical model derived from one published by the Sandia National Laboratory is our main premise for predicting expected power output for a visitor's array.
Predicted power for an array is calculated based on the system design and datasheet parameters of solar modules used, and on the current environmental condition. The generic shape of the IV and Power curves are scaled-up, based on to number of strings, and number of modules per string of solar modules. The resulting graph, plotted with labels showing the expected values, showing the ideal, optimal performance parameter values marked by the 'Ppeak' icon, on the graph.
Our visitor may print out this graph, together with conditions recorded in the 'performance' page, the visitor can mark the point that represents the actual performance values of his system on the graph. An experienced person, given this information, may deduce symptoms and probable causes for any exhibited under-performance of the system.