Abstract: A microprocessor based, power systems stabilizer operating through excitation control wherein all required stabilizing information is derived from sampled values of voltage and current taken from potential and current transformers. The instantaneous values of terminal voltage and current are processed using algorithms in the accelerating power signal digital processor portion of the microprocessor to thereby develop a value of instantaneous internal voltage, the value of slip frequency of such voltages in relation to rated frequency and a digitally filtered value of electrical power. The accelerating power is calculated from the rate of change of slip and electrical power. The values of accelerating power are processed with digital algorithms in a stabilizing signal compute section of the microprocessor to yield a stabilizing signal which provides the desired modulating action for damping the machine oscillations of the synchronous generator.

Abstract: A device for locating faults on the lines of electrical power distribution systems, including generally a variable impedance means adapted for connection in series with an electrical power line, and means for switching such variable impedance means between a first low impedance value when an initial current I.sub.1 of predetermined level flows on the power line for a predetermined period of time to enable detection of a fault condition, and a second high impedance value which limits the flow of current to a low level I.sub.2. A meter or other indicating device provides a reading of the current I.sub.1 to determine if a fault condition exists. In this fashion, the fault locator device limits both the magnitude and the time duration of the current when testing for a fault, so as not to adversely effect any system components.

Abstract: Apparatus for controlling high voltage by absorption of capacitive vars, comprising a stator (10) having a core and a three phase winding (14) connected to the high voltage, and a rotor (12) having magnetic material (20) exhibiting a sharp magnetic saturation. The rotor (12) includes longitudinally extending damper bars (22) imbedded in grooves or slots (24) in a manner similar to the bars used in a squirrel cage rotor. The magnetic structure of the rotor can be of two types--a symmetrical structure for asynchronous operation, and a salient pole structure for synchronous operation. In the case of the symmetrical rotor construction, the stator (10) and rotor (12) constitute a rotating induction reactor (8) which operates in the same manner as a free running, unloaded induction motor. The induction reactor (8) exhibits characteristics similar to a saturable reactor with respect to var versus voltage absorption, but does not have the undesirable harmonics normally present in the saturable reactor.