Systems and methods for retraining outlier detection limits in a building management system

A controller in a building management system, the controller comprising:

• a communications interface that receives performance values indicating the performance of a controlled process in the building management system, and provides control signals to building equipment, the control signals causing the building equipment to operate to affect the controlled process;
• an outlier detector that monitors performance values for the controlled process during a first time period relative to initial outlier detection limits and outputs a user alert message comprising a fault event notification in response to a detected change in the controlled process;
• a control limit trainer that generates new outlier detection limits in response to the detected change in the controlled process during the first time period, wherein the outlier detector monitors the performance values relative to the new outlier detection limits during a second time period to detect outliers during the second time period;
• a confidence difference calculator that calculates a confidence difference for an estimated confidence parameter based a number of outliers detected using the new outlier detection limits during the second time period;
• and
• a stationary process detector that detects when the confidence difference drops below a threshold value during the second time period, wherein the control limit trainer adjusts the new outlier detection limits in response to the confidence difference dropping below the threshold value;
• wherein the confidence difference calculator generates an estimated confidence parameter for each of the performance values observed during the second time period, and the confidence parameter is a ratio of a number of outliers detected during the second time period to a number of the performance values observed during the second time period.