Abstract: In a system stabilizing control system of controlling reactive power by a reactive power compensating device according to a voltage variation of an electric power system in which a capacitor is connected to a bus through a breaker, when the bus voltage drops, the capacitor is closed through the breaker to suppress a leading compensation reactive power amount caused by the reactive power compensating device, and when the bus voltage rises, the capacitor is disconnected through the breaker to suppress a lagging compensation reactive power amount caused by the reactive power compensating device.

Abstract: In a conventional reactive-power compensator using a static reactive-power compensator (SVC), there are many cases in which the SVC is operating in a state in which it generates an amount of reactive power equivalent to a large part of its capacity. When an unforeseen large voltage fluctuation occurs in this state, the SVC can not sufficiently generate the amount of reactive power required to mitigate the voltage fluctuation. In some cases, such a voltage fluctuation can not be brought under control. To address this situation, a reactive-power compensator utilizes a reactive-power control apparatus that includes a comparison voltage generator for generating, for a control target voltage and to mitigate voltage fluctuation, a comparison voltage restricted within predetermined limits and obeying a predetermined time-lag characteristic. A differential voltage generator generates a differential voltage that is the difference between the comparison voltage and the control target voltage.

Abstract: In a conventional reactive-power compensator using a static reactive-power compensator (SVC), there are many cases in which the SVC is operating in a state in which it generates an amount of reactive power equivalent to a large part of its capacity. When an unforeseen large voltage fluctuation occurs in this state, the SVC can not sufficiently generate the amount of reactive power required to mitigate the voltage fluctuation. In some cases, such a voltage fluctuation can not be brought under control. To address this situation, a reactive-power compensator utilizes a reactive-power control apparatus that includes a comparison voltage generator for generating, for a control target voltage and to mitigate voltage fluctuation, a comparison voltage restricted within predetermined limits and obeying a predetermined time-lag characteristic. A differential voltage generator generates a differential voltage that is the difference between the comparison voltage and the control target voltage.

Abstract: In a system stabilizing control system of controlling reactive power by a reactive power compensating device according to a voltage variation of an electric power system in which a capacitor is connected to a bus through a breaker, when the bus voltage drops, the capacitor is closed through the breaker to suppress a leading compensation reactive power amount caused by the reactive power compensating device, and when the bus voltage rises, the capacitor is disconnected through the breaker to suppress a lagging compensation reactive power amount caused by the reactive power compensating device.

Abstract: An apparatus for detecting the amplitude and phase of an a.c. signal. The apparatus includes a signal detection circuit for detecting the a.c. signal, a signal splitting circuit for splitting the detected a.c. signal into first and second a.c. signals out of phase with each other by 90.degree.. The signal splitting circuit includes a first order lag circuit having a phase lag, a subtractor, and first and second amplifying circuits. The apparatus also includes a phase compensation circuit coupled to the signal splitting circuit for receiving the first and second a.c. signals from the signal splitting circuit and for advancing the phase of an output signal of the apparatus by the phase lag of the first order lag circuit. The phase compensation circuit also includes an amplitude and phase detection circuit for detecting the amplitude and phase of the detected a.c. signal by implementing a polar coordinate transformation of the first and second a.c. signals received from the signal splitting circuit.

Abstract: An apparatus for detecting the amplitude and phase of an a.c. signal detects the a.c. signal with signal detection means (4), calculates an a.c. signal that is phase-shifted by the amount of the phase characteristic .phi. of the calculation circuit (14) at the frequency of the detected a.c. signal, multiplies the detected a.c. signal by cos .phi., and multiplies by 1/sin .phi. the multiplication result subtracted by the phase-shifted a.c. signal.

Abstract: A power converter controlling apparatus outputs voltage signals different in phase from phases of commutation voltages of each switching device by 90 degrees to transform the voltage signals and the commutation voltages in conformity with polar coordinate transformation, and outputs amplitudes of the commutation voltages and the phase differences of the commutation voltages to a reference phase based on the results of the transformation to operate phase-control angles of each switching device on the amplitudes and the phase differences.

Abstract: An apparatus for detecting the amplitude and phase of an a.c. signal. The apparatus includes a signal detection circuit for detecting the a.c. signal, a signal splitting circuit for splitting the detected a.c. signal into first and second a.c. signals out of phase with each other by 90.degree.. The signal splitting circuit includes a low-pass filter, and a differentiation circuit. The apparatus also includes a phase compensation circuit coupled to the signal splitting circuit for receiving the first and second a.c. signals from the signal splitting circuit and for advancing the phase of an output signal of the apparatus by the phase lag of the low-pass filter. The phase compensation circuit also includes an amplitude and phased detection circuit for detecting the amplitude and phase of the detected a.c. signal by implementing a polar coordinate transformation of the first and second a.c. signals received from the signal splitting circuit.

Abstract: An apparatus for detecting the amplitude and phase of an a.c. signal detects the a.c. signal with signal detection means (4), calculates an a.c. signal that is phase-shifted by the amount of the phase characteristic .phi. of the calculation circuit (14) at the frequency of the detected a.c. signal, multiplies the detected a.c. signal by cos .phi., and multiplies by 1/sin .phi. the multiplication result subtracted by the phase-shifted a.c. signal.

Abstract: An apparatus for detecting the amplitude and phase of an a.c. signal detects the a.c. signal with signal detection means (4), calculates an a.c. signal that is phase-shifted by the amount of the phase characteristic .phi. of the calculation circuit (14) at the frequency of the detected a.c. signal, multiplies the detected a.c. signal by cos .phi., and multiplies by 1/sin .phi. the multiplication result subtracted by the phase-shifted a.c. signal.