Abstract: An excitation system that includes an exciter for generating a field voltage for a rotor, a first automatic voltage regulator and a second automatic voltage regulator. The first regulator receives an output voltage of the power generation system as an input, and the second regulator receives the field voltage as an input. An output of the first regulator is provided as a second input to the second regulator. The first regulator is in selective electrical communication with the exciter through a first line conductor having first separable contacts such that an output of the first regulator may be selectively provided as an input to the exciter. The second regulator is in selective electrical communication with the exciter through a second line conductor having second separable contacts such that an output of the second regulator may be selectively provided as an input to the exciter.

Abstract: A stabilizer and synchronous electric power generator system using same that provides both power system damping and excitation limiter functionality. The stabilizer includes a processing unit and a memory storing routines executable by the processing unit. The routines are adapted to receive a voltage signal indicative of a voltage and a current signal indicative of a current output by the generator system, generate, utilizing the voltage and current signals, a power system stabilizer signal for damping oscillations and one or more excitation limiter function signals for controlling excitation level. The routines are also adapted to generate a feedback signal for the generator system by combining the power system stabilizer signal and one or more of the one or more excitation limiter function signals.

Abstract: An excitation control system includes a circuit breaker, a bridge and a controller. The bridge converts AC phases from the breaker to an excitation voltage. The controller includes an output to open the breaker, a first sub-system inputting voltages corresponding to the AC phases and outputting a sensed voltage, and a second sub-system inputting the excitation voltage and outputting a sensed excitation voltage. A first function detects a trip signal and responsively outputs firing signals to the bridge to provide a negative excitation voltage. A second function determines if a threshold is greater than the sensed voltage and if the trip signal is asserted, and responsively asserts the output to open the breaker. A third function determines if the trip signal is asserted and responsively delays for a predetermined time, unless a negative threshold is greater than the sensed excitation voltage, and after the predetermined time responsively asserts the output.

Abstract: An excitation control system for a generator includes an SCR bridge for providing an excitation voltage to the input of the generator; a regulator for regulating the excitation voltage; and a sensing sub-system for providing an electrical signal, such a generator current or generator watts, which is related to the output of the generator. The generator includes a circuit breaker for the one or more alternating current phases output by the generator. An output of the circuit breaker has a signal with a true state when the circuit breaker is closed and the generator is on-line and with a false state when the circuit breaker is open and the generator is off-line. A comparator provides a validation signal when the generator electrical signal is greater than a predetermined signal, such as minimum generator current or minimum generator watts, respectively. An OR gate qualifies the signal of the output of the circuit breaker with the validation signal and provides a qualified signal therefrom.

Abstract: Apparatus for protecting a synchronous generator from under-excitation, includes a limiter implemented as part of a microprocessor based voltage regulator. The limiter selectively characterizes one or more limiting parameters, such as, system stability, machine capability and loss of field protection, as straight line segments in the real/reactive power plane to provide versatile, easily modified limits on excitation.

Abstract: An electromechanical measurement system for acquiring dimensional data from a nuclear fuel assembly includes an underwater measurement assembly, support means for mounting same on the edge of a spent fuel pool, and a control and data acquisition and processing unit. The underwater measurement assembly includes an elongated strongback disposable vertically along a pool wall, adjustment mechanism on a support assembly permitting accurate positioning of the strongback. A support plate carries hydraulic clamps for clamping the top nozzle of a fuel assembly while it is supported from overhead, a clamp carried by the lower end of the strongback being engageable with the bottom nozzle for holding the fuel assembly in a selected orientation with the faces of the top nozzle vertical.