Patent ID: 8362789

Claim:
A test device, comprising: voltage measurement circuitry and devices; relaying and switching devices; and data acquisition, measurement and control devices operably connected with said voltage measurement circuitry and devices, and relaying and switching devices, wherein said test device is configured to determine a first set of results comprising at least a first voltage magnitude and a first voltage phase angle of an electrical node on an electrical power system, operably connect a load to the electrical power system at the electrical node using said switching devices and determine a second set of results comprising at least a second voltage magnitude, a second voltage phase angle, a second current magnitude, and a second phase angle of said second current of the electrical power system at said electrical node, wherein the second current magnitude and the second current phase angle are determined using the load and the second voltage magnitude and the second voltage phase angle, and compare the first set of results to the second set of results to determine at least one of an effective Thevenin equivalent circuit or Norton equivalent circuit for the electrical power system.