Abstract: A method and apparatus for controlling a current and/or power between interconnected power stations.A deviation from a base load in an active current or power flowing out of a power station and a deviation from a normal value in the terminal voltage of the power station are measured. A linear function of the ratio of the voltage deviation to the active current deviation is obtained, and a product of the active-current to voltage deviation function and an active current flowing out of the power station is calculated, and thus a reactive current is defined by the product.An internal generation current of the power station is controlled so as to coincide substantially with the sum of the current composed of the active current and the reactive current defined above, and other currents of the power station including the internal load current.

Abstract: Disclosed is an isolation amplifier, wherein a DC input signal is applied to the primary winding of a saturable reactor, the secondary winding of which is coupled with an oscillating circuit so as to supply the secondary circuit with a high-frequency current, and then the current flowing through the secondary winding is applied to a feed-back type low-pass filter, with which an output signal proportional to the DC input signal is extracted from the current flowing through the secondary winding.