Power source emulator and method for testing switchgear

A method for testing switchgear that detects different types of failures of a three-phase primary power source and is programmed, upon detection of such failure, to switch over to an alternative power source, by means of a power source emulator that includes at least two power sources for simulating a primary and an alternative power source, respectively, each of which provides a simulated three-phase power current to the switchgear that is identical in voltage and phase to the current distributed by the switchgear during normal operation but having less than 1% of the amperage, wherein each power source includes a single three-phase contactor for simultaneously controlling all three phases of the power source, and three solid-state relays connected downstream of the three-phase contactor for controlling each of the three phases of the power source, comprising the steps of:

• detachably connecting power inputs of the switchgear to the simulated primary and secondary power sources;
• opening and closing different combinations of the three-phase contactor and the three solid-state relays of the simulated primary power source to simulate various types of power failures that the switchgear is programmed to respond to, and
• monitoring a response of the switchgear to determine whether the switchgear is responding in accordance with its programming.