Induction Regulator for Power Flow Control in an AC Transmission Network

Abstract

An induction regulator for controlling the voltage amplitude and / or phase angle of a polyphase electric transmission network connected between the primary side and the secondary side of the transmission network. The rotor is fixed in relation to the stator and the volume between stator and rotor includes a magnetic volume with a region including a controllable magnetic flux region of solid material that has a relative permeability that is controllable by changing its temperature.

Description

FIELD OF INVENTION[0001]The present invention relates to an induction regulator for controlling the voltage amplitude and / or phase angle of a polyphase electric transmission network exhibiting a primary side with a primary voltage and a secondary side with a controllable secondary voltage, which induction regulator is connected between the primary side and the secondary side of the transmission network and comprising a stator with stator windings and stator poles and a rotor with rotor windings and rotor poles.[0002]The invention also relates to a method of controlling the voltage and the phase angle of a polyphase transmission network for high voltage with an induction regulator.[0003]The invention also relates to use of an induction regulator for power-flow control for a polyphase transmission network for high voltage.DESCRIPTION OF THE BACKGROUND ART[0004]The active power flow in an ac network is controlled by the equationP=U1U2Xsinδwhere U1 and U2 are the voltages at the transmi...

AI Technical Summary

Benefits of technology

[0037]By influencing the magnetic flux region in the volume between the stator and the rotor pole according to the invention, the magnetic flux in the volume may be controlled, which means that the amplitude of the secondary voltage vector may be controlled, and this without mechanical rotation of the rotor occurring. The control function of the induction regulator is thus achieved by the volume comprising a controllable magnetic flux region.

Problems solved by technology

If unforeseen events occur in a network, it will require that the generators be planned in a non-optimal way with regard to the production costs.

When influencing the active power flow by using a series capacitor, the reactance can only be reduced to a certain level and it is not possible to force the current irrespective of the state of the line since it is not possible in practice to overcompensate the line.

The disadvantages of existing UPFCs have primarily been associated with the difficulty of protecting the power electronics on the series-transformer side.

The control speed is low and considerable mechanical force is required to achieve the slow change of the output voltage.

An disadvantage of the induction regulator is that the voltage amplitude is changed when the angle δ is changed.

A device according to the first category is able to control the power flow within minimum and maximum ranges almost independently of the load states, whereas a control device according to the second category cannot always fulfil this requirement.

A drawback of the induction regulator is that the possibilities of control are limited to the voltage change that the secondary voltage vector achieves and this while changing the phase angle of the voltage.

This renders parallel connection of lines and apparatus difficult since an angular rotation brings about a voltage change and hence a circulating reactive effect.

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