Abstract: A power converter device that interchanges power between a first A. C. system and a second A. C. system, including an externally commutated power converter controlled such that the D. C. voltage of a D. C. line tracks a reference value, a voltage type self-commutated power converter which converts the output D. C. power of the externally commutated power converter to A. C. power under pulse width control and supplies the converted A. C. power to the second A. C. system, interchange power control means for controlling the phase difference angle of the voltage on the A. C. side of the voltage type self-commutated power converter and the voltage of the second A. C. system such that the interchange power tracks a reference value, and reactive power control means for controlling the control factor of the pulse width control such that the reactive power generated by the voltage type self-commutated power converter tracks another reference value.

Abstract: A power converter apparatus for a DC power transmission system or a frequency conversion system includes a control apparatus that functions such that during the operation of converters, when the output voltage of a constant reactive control circuit reaches the output voltage of a margin angle limited control circuit, a shunt reactor is interrupted or a shunt capacitor is closed, and when the output voltage of the constant reactive power control circuit reaches a control delay angle corresponding to the curve which has a difference .DELTA.Q compared with the curve P-Q at a minimum margin angle .gamma. min, the shunt reactor is closed or the shunt capacitor is interrupted.

Abstract: In the control apparatus of an AC/DC power converter, the occurrence of a single-phase line-open in the AC power line is detected by an open-circuit detector so that a detection signal is generated. The control angle of a converter on the side of occurrence of the single-phase line-open is kept at a given value based on the detection signal. At the same time, the current set value of the automatic current regulator is also kept at a fixed value based on the detection signal.

Abstract: In control of an AC-DC converter system including AC-DC converters (1A, 1B) having respective AC terminals connected to AC power systems (6A, 6B) and having respective DC terminals connected to each other, a fault in the AC power systems is detected, and upon occurrence of a fault in any of the AC power systems, the DC current of the AC-DC converter which is connected to the sound AC power system is adjusted in such a manner as to maintain the AC voltage of the AC-DC converter which is connected to the sound AC power system at a desired value.

Abstract: A control method of the invention is formed with the steps of when a margin angle .gamma. reaches a given minimum margin angle .gamma.min during the operation of a rectifier and inverter, a shunt reactor is disconnected from, or a shunt capacitor is connected to, an AC line of the inverter, and when the margin angle .gamma. exceeds the minimum margin angle .gamma.min by a predetermined value, the shunt reactor is connected to, or the shunt capacitor is disconnected from, the AC line.

Abstract: A power converter control apparatus includes an automatic power controller for controlling a rectifier and an automatic reactive power controller for controlling an inverter. The inverter is coupled via DC power transmission lines to the rectifier. An output from the automatic power controller is utilized to change a control angle (or margin angle) of the inverter if a DC current flowing through the DC power transmission lines increases to exceed a rated current value of the apparatus, thereby allowing a stable power transmission.

Abstract: A converter control system for DC power transmission line performs the following operation. When the DC current flowing through an inverter decreases to a value being smaller than a rated current value by a value in excess of a predetermined value, a reference voltage value determining the DC voltage of the inverter decreases. The decrease of this reference voltage value is limited to a given extent, so that a partial constant current characteristic portion appears at the voltage decreased portion in the DC voltage/current characteristic of the inverter. Then, an automatic voltage regulator of the inverter is rendered always active.

Abstract: In a method and a system for terminating inverter operation of a converting device connected to a DC power transmission system and having a bridge connection of thyristor valves, absence of a current flowing through the converting device is detected to provide an absence detection signal indicative of such absence, and the absence detection signal is used as one condition for effecting termination of the inverter operation. According to the invention, the absence is found when all the valves in at least one of the lower potential side and the higher potential side are found concurrently non-conducting, and each valve is found non-conducting when a voltage is found present across each valve.

Abstract: In the frequency control mode, a switch is ON. A power difference is fed back to an adder through a limiter and is compared with an output from a power setter. A difference signal from the adder is supplied to an adder to obtain a difference with detected power. By the feedback loop, the preset power is set to be substantially equal to the detected power. While the difference is greater than a predetermined value, an output from a level detector is at logic level "0". Even if a mode switch instruction is received in this state, an AND gate does not produce an output signal and the mode changing is not performed.

Abstract: A control device for a converter used in a DC transmission system comprises an automatic current regulator, an automatic margin-angle regulator and an automatic voltage regulator. The output of the automatic voltage regulator is supplied to the automatic margin-angle regulator to vary a margin-angle reference of the automatic margin-angle regulator.

Abstract: In a gate control circuit for a thyristor converter, in which thyristor valves each having a plurality of series thyristors are connected to form a bridge, a detector for detecting a forward voltage applied across one of the thyristors and a circuit for supplying a gate signal to the gate of that thyristor valve are provided. The gate control circuit further comprises a circuit for supplying, when a bypass pair operation of the thyristor converter is switched over to a deblock operation, a signal to the gate of a continually conductive thyristor valve according to a control signal to a thyristor valve to be operated in deblock with the continually conductive thyristor valve and also a gate signal to the continually conductive thyristor valve.