Bbc Brown, Boveri & Company, Limited

Asea Brown Boveri Ag

Hans Glavitsch

Gerhard Guth

Michael Vitins

Mohamed Rahmani

A method is specified for operating a multiphase line which is included in a transmission network and can be disconnected if faults occur, for the transmission of electrical power. The method comprises the following method steps: a) detecting upstream and downstream of the line, data which characterize the operating status of the transmission network, b) processing the detected data in order to identify a fault, c) switching off at least one faulty phase of the line on the basis of the identified fault, and d) activating a balancing compensator which feeds compensation currents into the transmission network such that the currents flowing in the transmission networks form a balanced system. This method has the major advantage that, now, even lines subject to faults can be used for the transmission of electrical power.

Method for operating a line

A transformer which is suitable for connecting with a compound network and renders possible shifting the phase angle of the secondary side-output voltage in relation to the primary side-input voltage. The secondary windings are divided into winding stages and there are provided lines and switches, by means of which these winding stages can be selectively connected in series. Since the phase angle of the voltage in each winding stage coincides with the angle of the corresponding winding, it is possible to vectorially add in this manner partial voltages with different phase angles, so that at the output terminal of one winding there appears a composite voltage whose phase angle is aligned in the same direction as said one winding or, in relation to such direction, is shifted through a predetermined angle value in clockwise direction or in counterclockwise direction.

Transformer for the controllable shifting of the phase angle of output

Controllable phase shifters containing reactances and valve switching devices are used for compensation and stabilizing purposes in alternating current-energy transmission systems. There is desired a phase shift which can be continuously controlled within variable limits and with comparatively low expenditure in circuit components. There is provided at least one shunt circuit branch between primary terminals having mutual phase shifted voltages, and a tap provided as a secondary terminal supplies a secondary voltage or potential having a phase between that of the primary terminals. At both sides of the secondary terminal there are arranged in the shunt circuit branch preferably complementary reactive impedances. At least one valve switching device, controllable with respect to its gating behavior, is arranged in series or parallel to one such impedance and renders possible changing the magnitude of the impedance which is effective for the fundamental oscillation, and thus, a change of the control phase angle. Preferably valve switching devices are provided at both sides, and, if desired, in combination parallel and in series with the impedances to both sides of the secondary terminal, thereby realizing the advantage of a phase angle control in both directions and over wide ranges of the primary phase angle.

Controllable phase shifter

A method for locating a fault on a line wherein starting from a fault-free operating state of the line there is derived a substitute-measurement voltage signal which corresponds at least approximately to a frequency component of a line voltage both in magnitude and phase and is approximately independent of breakdown of the line voltage at least for a limited time interval. The substitute-measurement voltage signal is used to form at least one substitute-traveling wave signal and a substitute-evaluation signal.

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Nussbaumen, Switzerland

Hans Glavitsch