Condition Monitoring Method for Pump Assembly, and Power Converter System for Pump Assembly Utilizing Said Method

A power converter system for a pump assembly comprising:

• a power converter adapted to supply power to an electric motor which is adapted to be connected to a pump;
• and
• a control system adapted to control the power converter;
• wherein the control system is adapted to carry out the condition monitoring method including the steps determining at least two characteristic performance curves of the pump;
• estimating at least two instantaneous performance variables of the pump for a plurality of operating points of the pump assembly;
• determining operating point data for the pump assembly based on the at least two characteristic performance curves of the pump and the estimated instantaneous performance variables of the pump, the operating point data comprising an estimated flow rate and an estimated head for the plurality of operating points of the pump assembly;
• and
• estimating the system curve for the pump assembly based on the operating point data,
• wherein the operating point data is determined during normal operation of the pump assembly, and the method includes a curve fitting procedure, in which estimated system curves are fitted on the operating point data,
• wherein the curve fitting procedure includes providing estimated system curves for a plurality of fitting time windows, wherein each of the plurality of fitting time windows includes a plurality of operating points of the pump assembly,
• wherein the plurality of fitting time windows is provided over a long period of time in order to detect a change in an operating state of the pump assembly for assessing whether the pump assembly requires maintenance.