Abstract: A voltage stability prediction system is configured to predict voltage stability of a power system under a contingency. The voltage stability prediction system in this regard may execute model-based contingency analysis using a model of the power system to predict, as of a first time, voltage stability of the power system post-contingency. The voltage stability prediction system also obtains, from phasor measurement units (PMUs) in the power system, synchrophasor measurements that indicate, as of a second time later than the first time, phasors in the power system pre-contingency. Further, based on the model-based contingency analysis and the synchrophasor measurements, the voltage stability prediction system predicts, as of the second time, voltage stability of the power system post-contingency.

Abstract: A voltage stability prediction system is configured to predict voltage stability of a power system under a contingency. The voltage stability prediction system in this regard may execute model-based contingency analysis using a model of the power system to predict, as of a first time, voltage stability of the power system post-contingency. The voltage stability prediction system also obtains, from phasor measurement units (PMUs) in the power system, synchrophasor measurements that indicate, as of a second time later than the first time, phasors in the power system pre-contingency. Further, based on the model-based contingency analysis and the synchrophasor measurements, the voltage stability prediction system predicts, as of the second time, voltage stability of the power system post-contingency.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the imaginary part of the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface. The apparatus computes an index indicating the voltage stability as a function of this tracked Thevenin equivalent voltage and impedance.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface. The apparatus computes an index indicating the voltage stability as a function of this tracked Thevenin equivalent voltage and impedance.

Abstract: The arrangement of an electric machine, a connecting system and a converter, includes the connecting system connected between the electric machine and the converter. The connecting system has an enclosure that houses non-shielded conductors each non-shielded conductor is connected between a phase of the electric machine and the inner side of the converter. The non-shielded conductors of the connecting system that are connected to an operating phase of the electric machine are adjacent to conductors of the connecting system that are not connected to operating phases of the electric machine.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the imaginary part of the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the imaginary part of the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface. The apparatus computes an index indicating the voltage stability as a function of this tracked Thevenin equivalent voltage and impedance.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface. The apparatus computes an index indicating the voltage stability as a function of this tracked Thevenin equivalent voltage and impedance.

Abstract: A voltage stability monitoring apparatus monitors the voltage stability of a transmission corridor through which power flows between different parts of a power system. The apparatus monitors an equivalent load impedance at an interface between the transmission corridor and a part of the power system designated as generating the power. This equivalent load impedance at the interface comprises a ratio of a voltage phasor at the interface to a current phasor at the interface. The apparatus tracks a Thevenin equivalent voltage and impedance of the designated part by separately updating that voltage and impedance. Notably, the apparatus updates the imaginary part of the Thevenin equivalent voltage to reflect the magnitude of any changes in the voltage phasor that are associated with large variations in the magnitude of the equivalent load impedance at the interface. The apparatus computes an index indicating the voltage stability as a function of this tracked Thevenin equivalent voltage and impedance.

Abstract: An electric generator (1) includes a casing (2) that envelops a stator (3) and a rotor (4). The casing (2) has an aperture (5) through which the generator casing inside (7) is inspectable during generator operation. A method includes inspecting during generator operation, through the aperture (5) of the casing (2), the casing inside (7).

Abstract: The arrangement of an electric machine, a connecting system and a converter, includes the connecting system connected between the electric machine and the converter. The connecting system has an enclosure that houses non-shielded conductors each non-shielded conductor is connected between a phase of the electric machine and the inner side of the converter. The non-shielded conductors of the connecting system that are connected to an operating phase of the electric machine are adjacent to conductors of the connecting system that are not connected to operating phases of the electric machine.

Abstract: A cooling system for bushings of an electric generator, which includes a casing housing a stator and a rotor connected to a rotor shaft activating at least a fan defining at least a high pressure zone and a low pressure zone. The generator has a plurality of phases electrically connected to hollow phase rings that are electrically connected to bushings supported by the casing and having cooling circuits to let a cooling medium pass through them to cool them. The outlets of the bushing cooling circuits are housed in the high pressure zone and are connected to inlets of the hollow phase rings. A method for cooling the bushings of an electric generator is also provided.

Abstract: A device (10) for connecting together end winding parts (1) of stator bars (2) of an electric generator includes a first and a second element (11, 12) having sloped facing surfaces (13) defining two trapezoidal seats each housing a trapezoidal cursor (14), and one or two screws (15), axially fixed and rotatably movable with respect to the first and second element (11, 12) and having a threaded portion inserted in a threaded through hole (17) of the cursor (14).

Abstract: The disclosure relates to a method of detecting and managing voltage instability in power systems operations. The disclosed method identifies and follows Thevenin and load impedance values as they fluctuate in a power system using synchrophasor measurements. The values are recursively estimated and entered into calculations to identify stability margins through a simple P-Q plane representation to determine if load shedding is necessary.

Abstract: A cooling system for bushings of an electric generator, which includes a casing housing a stator and a rotor connected to a rotor shaft activating at least a fan defining at least a high pressure zone and a low pressure zone. The generator has a plurality of phases electrically connected to hollow phase rings that are electrically connected to bushings supported by the casing and having cooling circuits to let a cooling medium pass through them to cool them. The outlets of the bushing cooling circuits are housed in the high pressure zone and are connected to inlets of the hollow phase rings. A method for cooling the bushings of an electric generator is also provided.

Abstract: An electric generator (1) includes a casing (2) that envelops a stator (3) and a rotor (4). The casing (2) has an aperture (5) through which the generator casing inside (7) is inspectable during generator operation. A method includes inspecting during generator operation, through the aperture (5) of the casing (2), the casing inside (7).

Abstract: A device (10) for connecting together end winding parts (1) of stator bars (2) of an electric generator includes a first and a second element (11, 12) having sloped facing surfaces (13) defining two trapezoidal seats each housing a trapezoidal cursor (14), and one or two screws (15), axially fixed and rotatably movable with respect to the first and second element (11, 12) and having a threaded portion inserted in a threaded through hole (17) of the cursor (14).

Abstract: An electrical power system includes a transmission line for transmitting electrical power, series capacitance compensation series-coupled to the transmission line adjacent one end thereof, where the series compensation includes a capacitance having a value (−j XCAP), and a protective relay at the one end of the transmission line for monitoring line voltages and line currents on the transmission line. Upon sensing a fault, an impedance Z of the line is calculated based on the monitored line voltages and line currents. The calculated impedance Z is adjusted according to the value of the capacitance of the series compensation (−j XCAP) to result in a modified impedance ZMOD, and the phasor angle Of ZMOD is examined to determine the direction of the sensed fault. The fault is in a first direction if the phasor angle is between X and X+180 degrees and is in a second direction opposite the first direction if the phasor angle is between X+180 and X+360 degrees.

Abstract: An improved high impedance fault (HIF) detection system comprises an analyzer located at a circuit breaker or substation with feeders, wherein the analyzer analyzes current and/or voltage waveforms to detect a HIF on the feeder or on one of a plurality of laterals coupled to the feeder; a plurality of remote outage detectors located respectively at corresponding customer sites, each remote outage detector including a mechanism to detect a loss of potential or power at the corresponding site; and a computer in communication with the analyzer and the remote outage detectors.

Abstract: An accurate impedance measurement method for a power system transmission line is disclosed for improving various protection functions, i.e., distance protection and/or fault location estimation. The method is less sensitive to harmonics and other transient problems introduced to power systems by series capacitance and the like, and is easily incorporated into existing protective relays. In the method, a number (n) of current and voltage samples (Ik, Vk) representative of values of current and voltage waveforms are measured, respectively, at successive instants of time on a conductor in a power system. The number n is an integer greater than I and the index k takes on values of 1 to n. Resistance (R) and inductance (L) values are computed in accordance with an equation in which R and L are related to sums of differences in values of successive current and voltage samples. A prescribed power system function is then performed based on the computed R and L values.