Bbc Brown, Boveri & Company, Limited

Brown, Boveri & Cie Ag

Asea Brown Boveri Inc.

Asea Brown Boveri Ag

Bbc Aktiengesellschaft Brown, Boveri & Cie

Michael Hausler

Kadry Sadek

Karl-Werner Kanngiesser

Peter Dahler

Karl Werner Kanngiesser

Josef Kauferle

Walter Pfyl

Philippe Huber

Kadry Sadex

A two-quadrant converter having a connected superconducting magnetic memory used as a chopper circuit or an actuator for stabilizing networks and for short-term bridging of power failures (e.g., uninterrupted power supply). For example, a two-quadrant converter is connected on the input side to an intermediate d.c. circuit of a converter whose intermediate circuit voltage is stabilized by an indirect capacitor. A magnetic memory is charged and discharged, respectively with energy in cyclic intervals, i.e. in conjunction with interposed free-wheeling intervals. Charging takes place via triggered thyristors, discharging via conducting diodes, with blocked thyristors. When the magnetic memory is in a charged state and is to be neither charged nor discharged over lengthy intervals, its current can be conducted in the free wheel via a closed mechanical switch connected in parallel.

Energy storage circuit with DC chopper superconducting reactor

In order with a low degree of equipment complexity to convert two alternating-currents of 16 2/3 Hz of two separate single-phase generators (G1, G2) of approximately the same power into a three-phase current with 50 Hz, the single-phase generators are connected via a SCOTT transformer (Tr1) to a rectifier (SR1) of a converter with a direct-voltage intermediate circuit (3-6). The direct current transmitted through the direct-voltage intermediate circuit is transformed into three-phase current by two inverters (SR2, SR3) connected in series, and supplied to a national power system (10) via power transformers (Tr2, Tr3). The two single-phase generators (G1, G2) are controlled by one generator voltage controller (42) in each case, which affects the excitation of the single-phase generators (G1, G2) via a field rectifier (43), at the same amplitude of their generator voltages (u1, u2). Moreover, the single-phase generators (G1, G2) are controlled at a phase shift of their generator voltages (u1, u2 ) of 90.degree..sub.el by a load angle controller as a function of the load angles (.delta.1, .delta.2). For this purpose, desired-value signals (P1.sub.s, P2.sub.s) are formed by a turbine balance controller in order to control the fuel supply of turbines (Tu1, Tu2), which drive the single-phase generators (G1, G2).

Arrangement for converting two single-phase alternating currents into a

With electric valves (7) having several series-connected thyristore (T1 . . . Tn; T1' . . . Tn'), individual thyristors may become defective, so that they do not withstand the blocking voltage applied to them. For the simplified checking of such defects, a process is specified which does not require any individual monitoring on the spot, i.e. for high potential. For this purpose, in the blocked state of the valve (7), all thyristors of one current direction, apart from at least one thyristor being tested, are triggered within a predeterminable triggering interval. If a valve current (i.sub.R) then flows, an indicating and registering device (A1 . . . An) indicates in which thyristor stage the defect has occurred. This status check is preceded by a preliminary test in which it is checked whether all thyristor triggering channels are in order. All thyristors are triggered in this test. If no valve current (i.sub.R) occurs, a triggering channel fault signal (S.sub.U0) is generated.

Process for the fault monitoring of an electric valve

A compensation circuit for reactive power balance includes a capacitor, inductor and rectifier connected in series to a power system. In order to protect the rectifier from misfires of the thyristors, two discharge devices are connected in parallel to the series circuit from the common points in the series circuit. This protects the thyristors in case of a double misfire.

Circuit arrangement for the compensation of reactive power in an

In order to place into operation a group of power converters which are connected in series as concerns the direct-current mode and in parallel as concerns the alternating-current mode, of a power or current converter operating in a rectifying mode of a high-voltage direct-current transmission installation, the control pulses of the group of power converters to be placed into operation are set at a range of approximately 100 to 115 electrical degrees. The bypass or shunt switch of such group of power converters subsequently receives an opening command. The control pulses, after accomplishment of opening of the bypass or shunt switch are shifted in accordance with a predetermined linear ramp function in the rectifying range and thereafter the control pulses are delivered by means of a pole current regulator. The placement into operation of a power converter operating in the inverting mode is accomplished in a similar fashion. Reactive power swings or fluctuations between the network and the power converters are avoided.

Method for placing into operation a series connected group of static

Method for controlling a high-voltage d-c (HVDC) transmission installation with a short coupler according to the marginal current method, which includes levelling out voltage variations of longer than a given duration in the three-phase voltages at terminals of the short coupler with step switches of the converter transformers, and controlling the invertor to form a constant control angle.

Control of a HVT (high voltage D-C transmission) short coupler

Circuit for the compensation of harmonic currents in a network, including a wideband highpass filter having a choke connected in parallel with a damping resistor and a capacitor connected in series therewith, and a harmonic converter connected to the highpass filter.

Circuit arrangement and method for the compensation of harmonic currents

Method of taking a pole of high-voltage d-c transmission system (HVDCTS) out of service, having a rectifier station connected to a first three-phase network and an inverter station connected to a second three-phase network, two d-c lines connected from one station to the other, each station being divided into halves, the station halves of each station being connected together on one side to a station center grounding electrode, the other side of each station being connectible to the positive d-c line so as to form a positive pole, and to the negative d-c line so as to form a negative pole, and residual-current switching means for taking a pole out of service, which includes grounding the station pole through a pole grounding switch which is spaced from the station center grounding electrode, and subsequently commutating a partial fault current of other poles, occurring from the pole being taken out of service, into the station center grounding electrode by the residual-current switch in the form of a circuit breaker.

Method of taking a pole of a high-voltage d-c transmission station out

A method and apparatus for controlling the real and reactive power behavior of a high voltage transmission (HDT) system characterized by a rectifier station connected to a first three phase network and an inverter station connected to a second three phase network. The rectifier and inverter stations have positive and negative station-halves connected to each other over positive and negative D.C. transmission lines to form positive and negative poles, each station having a common ground or return wire. Each station is equipped with current and voltage regulators, as well as control angle and quenching angle regulators whereby in case of the tripping of line protective devices monitoring line current in a faulty pole, and the consequent unloading of the faulty pole, the regulation of the intact pole assumes control for a short time to protect against network transients resulting from the load drop. In the event of a line disturbance, both the current set point for the current regulator and the control angle set point for the control angle regulator of the intact station-half of the intact pole are increased according to preset functions, with the control angle set point subordinated to the magnitude of the current angle set point.

Method and apparatus for controlling the real and reactive power

Method of starting up a station of a high-voltage d-c transmission system having at least two converters which with current and voltage regulators are connectible to d-c and three-phase networks or power plants and are selectively operable as rectifiers and inverters, and for starting up the three-phase network or power plant connected to the station, the station at the start-up time, being isolated from a functioning three-phase network or power plant and auxiliary equipment required for the operation thereof, which includes feeding from the d-c side of the high-voltage d-c transmission system active power required for starting up the station of the high-voltage d-c transmission system, and feeding from an independent reactive-power source reactive commutation power required for the start-up operation of the station of the high-voltage d-c transmission system as well as other reactive power required during the start up.

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Hirschberg, Germany

Michael Hausler