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Patent

Device in current converters

Jerker Andersson
TLDR
In this paper, a static converter with a delay angle control device, a control amplifier for controlling the delay angle, and an arrangement for blocking the converter is presented. But the converter does not have the ability to control the output of the blocking device over a switch delaying circuit.
Abstract: 
In a static converter which includes a delay angle control device, a control amplifier for controlling the delay angle control device, and an arrangement for blocking the converter. In order to provide for rapid starting of the converter a limiting member for limiting the delay angle of the converter so as to limit the direct voltage of the converter is controlled by the output signal of the blocking device over a switch delaying circuit. A transient order device is also connected to the input side of the control amplifier to increase the input signal of the amplifier and the transient order device is actuated by the blocking means for the DC transmission line connected to the converter. An under-voltage sensitive device actuated by the voltage in an AC network connected to the converter is connected in parallel to the blocking device, and the two parallel devices are connected to the limiting member and the transient order device by an OR gate.

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Patent

Starting inhibit scheme for an hvdc converter

D Demarest
TL;DR: In this article, a high-voltage converter comprises a plurality of electric valves interconnected in a bridge configuration between a-c and d-c electric power conductors and means for cyclically firing the valves in a normal sequence.
Patent

Minimum valve voltage method and control apparatus for hvdc power converters

Philip Chadwick
TL;DR: In this paper, a minimum valve voltage firing control method and circuit for HVDC thyristor power converter circuit operated in the rectifying mode is presented. But this method requires the valve of the commutating voltage across the respective power converter valves to be sampled and the minimum sampled value during each valve firing stored on a capacitor through the medium of suitable valve voltage sampling and gating circuits.
Patent

Phase unbalance or open-phase detecting apparatus

M Huruse
TL;DR: In this article, a plurality of current transformers have primary windings connected to a phase signal circuit and secondary winding each having a pluralityof terminals, respectively, and the difference signals are derived from the outputs of the positive direct signal generating means and the negative direct signals generating means.
Patent

Direct-current voltage current converter conversion and quit method and device

Dong Yunlong, +8 more
TL;DR: In this paper, two direct-current voltage current converter conversion methods and devices and two direct current voltage current conversion quit methods were presented for multi-end flexible direct current power transmission systems or flexible directcurrent power grid systems.