Abstract: In order to provide an apparatus (1) for flexible power transmission and for deicing of a high-voltage line, which has a plurality of phases, by means of direct current, with an AC voltage connection of the high-voltage line which has a number of phases corresponding to the phases of the high-voltage line, each phase having at least one inductance (6) and a valve circuit (10) connected in series with each inductance (6), with the valve circuit (10) being connected by means of a junction point (11) to the AC voltage connection, and having a first current path (14) with a first power semiconductor valve (12) and a second current path (15) with a second power semiconductor valve (13), with the power semiconductor valves (12, 13) being connected in opposite senses with respect to one another with reference to the junction point (11) and in which case the first and the second current path (15) can be connected to a TCR star point by means of at least one star point switch (16, 17), whose design is simple and at th

Abstract: A device for transmitting electric power between alternating voltage networks includes converters interconnected by direct current lines and provided each with several six-pulse conversion bridges. The six-pulse conversion bridges of one same converter are capable of being connected to an alternating voltage network associated with the converters via inductances differently phase-shifted. A control unit is provided to energize the valves of the six-pulse conversion bridges. The device is more economical and the converters are interconnected by a plurality of direct current circuits, each direct current circuit being galvanically separated from at least an alternating voltage network.

Abstract: A device (8), for adjusting the impedance of a high voltage line (9), supplying an alternating current, has at least one control coil (2), which may be inserted in series in the high voltage line (9) and at least one switching device (3,10), provided for each control coil (2). The device is compact and economical. A control unit (4) for controlling each switching device (3,10) is also provided, such that the reactance of the control coil (2), acting in the device may be adjusted by the switching of the switching device (3,10), whereby each switching device (3,10) is arranged parallel to the corresponding control coil (2) in a parallel branch (5).

Abstract: In order to provide an apparatus (1) for flexible power transmission and for deicing of a high-voltage line, which has a plurality of phases, by means of direct current, with an AC voltage connection of the high-voltage line which has a number of phases corresponding to the phases of the high-voltage line, each phase having at least one inductance (6) and a valve circuit (10) connected in series with each inductance (6), with the valve circuit (10) being connected by means of a junction point (11) to the AC voltage connection, and having a first current path (14) with a first power semiconductor valve (12) and a second current path (15) with a second power semiconductor valve (13), with the power semiconductor valves (12, 13) being connected in opposite senses with respect to one another with reference to the junction point (11) and in which case the first and the second current path (15) can be connected to a TCR star point by means of at least one star point switch (16, 17), whose design is simple and at th

Abstract: A device for transmitting electric power between alternating voltage networks includes converters interconnected by direct current lines and provided each with several six-pulse conversion bridges. The six-pulse conversion bridges of one same converter are capable of being connected to an alternating voltage network associated with the converters via inductances differently phase-shifted. A control unit is provided to energize the valves of the six-pulse conversion bridges. The device is more economical and the converters are interconnected by a plurality of direct current circuits, each direct current circuit being galvanically separated from at least an alternating voltage network.

Abstract: A device (8), for adjusting the impedance of a high voltage line (9), supplying an alternating current, has at least one control coil (2), which may be inserted in series in the high voltage line (9) and at least one switching device (3,10), provided for each control coil (2). The device is compact and economical. A control unit (4) for controlling each switching device (3,10) is also provided, such that the reactance of the control coil (2), acting in the device may be adjusted by the switching of the switching device (3,10), whereby each switching device (3,10) is arranged parallel to the corresponding control coil (2) in a parallel branch (5).

Abstract: The novel circuit arrangement is used for the static generation of a variable electric output, as is common in static reactive-power compensation systems. According to the invention, a voltage is applied to a consumer, i.e. to a capacitor and/or an inductor, and a transformer (T) has at least two power-control windings (W1, W2) in a secondary circuit, said windings being connected electrically in series via bridge circuits (B1, B2). In their branches, the bridge circuits contain static switches (BSS1 . . . 4) in an inverse-parallel connection, said switches can be selectively connected or disconnected.

Abstract: The novel circuit arrangement is used for the static generation of a variable electric output, as is common in static reactive-power compensation systems. According to the invention, a voltage is applied to a consumer, i.e. to a capacitor and/or an inductor, and a transformer (T) has at least two power-control windings (W1, W2) in a secondary circuit, said windings being connected electrically in series via bridge circuits (B1, B2). In their branches, the bridge circuits contain static switches (BSS1 . . . 4) in an inverse-parallel connection, said switches can be selectively connected or disconnected.

Abstract: The invention relates to a hybrid for an AC mains system, with the hybrid filter having a passive and an active filter which are electrically connected in series, and with the active filter having a voltage source. According to the invention, a tuned filter, which is tuned to the rated frequency of the AC mains system, is electrically connected in parallel with the active filter. This results in a hybrid filter for an AC mains system, whose active filter is not loaded by the fundamental current component.

Abstract: A thyristor-controlled capacitor bank includes a thyristor switch and a capacitor bank. The capacitor bank is split into at least two series-connected capacitor groups. A series circuit including a thyristor switch and an inductor coil is connected in parallel with the capacitor group which is remote from a capacitor group at a mains power supply connection. A thyristor-switched capacitor bank is thus obtained which has a thyristor switch that therefore only needs to be constructed for a fraction of the mains power supply voltage itself, which is a major advantage for economic reasons.

Abstract: A method and an apparatus can determine the orders (z) of non-characteristic harmonic currents (Ih) of a second power supply grid, which is coupled to a first power supply grid using an HVDCT system. The apparatus and method also compensates for these non-characteristic harmonic currents (Ih), which are produced as a result of distortion (Uh) of the supply voltage (U1) which exists in the first grid because of a low-frequency harmonic and passes through the short coupling. The order (n) of the existing non-characteristic harmonics is determined by a voltage and/or current measurement of the voltage (U1) of the grid, from which order (n) the order (z) of the generated non-characteristic harmonics in the second grid is determined by a provided voltage-symmetry signal (SMG). This order (z) is supplied to filter logic of a compensation system. The energy quality is thus considerably improved, particularly in the case of grids which are not rigid.

Abstract: Where different 3-phase systems are connected to each other via two static converters having an intermediate direct-current circuit, the exchange of power via the intermediate direct-current circuit can be interrupted by a severe disturbance, for example by failure of a static-converter or by line or busbar faults causing a short-circuiting of one of the static converters. This interruption means a change in the balance of effective power and, associated with this, a shedding of reactive load for the other undisturbed 3-phase system. To reduce high dynamic overvoltages which can lead to plant components being endangered or to operational disturbances, the firing angle of the static converter remaining in operation is regulated with dependence on the alternating voltage of the alternating-current system connected to this static converter, in such a manner that the overvoltage is reduced. This is carried out by regulating the current.

Abstract: If in a high-voltage d-c transmission system (HVDCTS), a resonance frequency of an a-c voltage network (NB) connected to the inverter (1B) is located in the vicinity of a voltage component contained in the a-c voltage network, a resonance frequency which often cannot be compensated by a current regulator controlling the rectifier stage (1A) is coupled into the d-c circuit of the HVDCTS via the inverter. Therefore, resonance phenomena which requires an emergency shutdown of the HVDCTS are generated. Therefore, a pilot quantity (U'.sub.d) is formed with a defined phase shift relative to the resonance oscillation of the HVDCTS voltage and added to the output of the current regulator. Thereby, a constant HVDCTS current can be generated for a given operating point and the resonance in the a-c voltage network (NB) can be damped. If the resonance oscillation is determined by two quantities (U'.sub.d, i'.sub.

Abstract: To reduce unwanted current oscillations such as, for example, of the second harmonic of the system frequency (f.sub.o), the firing angles (.alpha.1, .alpha.2) of a link-circuit rectifier (1) and of a link-circuit inverter (2) are compensatingly acted on in push-pull mode. For this purpose, a direct-current link-circuit current signal (S5, S5'), which contains the instability or the current oscillation to be compensated, is fed by means of a current detector (5, 5') to a bandpass filter (16, 16', 16") which is tuned to the frequency (f.sub.o, f.sub.x) of the respective current oscillation. The phase of a bandpass filter output signal (S16) is shifted by 90.degree. trailing in a 90.degree. phase-shifting section (15, 15', 15"). A compensating signal (S15,S15', S15") obtained in this manner is fed to first and second function generators (13, 13', 13"; 14, 14', 14").

Abstract: In this three-phase filter circuit system for static converter systems and particularly high-voltage direct-current short ties, at least two high-pass filters are provided which are connected in parallel. Each high-pass filter consists of a choke connected in parallel with a resistance and, in series with both, a capacitor and can be individually connected to the three-phase busbar via a switch. The filter circuits are used not only for reducing harmonics but also as compensating devices, which can be switched in steps, for the reactive power requirement of the static converters so that in the lower partial load range of the system one of the filter circuits is disconnected for reasons of reactive power balance. In order to improve the filtering effect in this lower partial load range, a bus-coupler switch connecting in each case the common junctions of capacitor, resistance and choke of the high-pass filters is closed.

Abstract: In a reactive power compensator used for capacitive or inductive reactive powers in alternating-voltage networks, a capacitor is connected to an alternating-voltage network for a short time by means of a thyristor switch. In order to reduce the voltage load on the thyristor switch, a discharge circuit is connected in parallel with the capacitor. Via this circuit, the capacitor can discharge, after being disconnected from the alternating-voltage network, with such a speed that the voltage occurring at the thyristor switch is no greater than about 1.5 times the maximum network voltage. In the discharge circuit, a variable inductive reactive resistance can be a discharge circuit choke having an iron core or the primary winding of a transformer. When the capacitor is connected to the alternating-voltage network, the discharge circuit choke is unsaturated and its reactive resistnace is large (or the transformer secondary is open) so that no significant leakage current can flow via the discharge circuit.

Abstract: 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.

Abstract: 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