Asynchronous nonsalient-pole compensators with total air cooling1

Abstract

Translated from Élektricheskie Stantsii, No. 11, November 2008, pp. 62 -65. The fundamental parameters and construction of asynchronous compensators, soon to be produced by the "Silovye Mashiny" -"Élektrosila" Joint Stock Company in 2008, are considered. The compensator has a massive nonsalient-pole rotor with two excitation windings, shifted by 90°(in electrical angles), supplied from controlled reversible power sources. The compensators provide delivery-consumption of reactive power in the ±100 Mvar range with the possibility of short-term double forcing of the power output and improved dynamic characteristics compared with synchronous compensators.One of the most important problems in electric power engineering is providing regulation of the reactive power in the electric network. In addition to modes of operation that require reactive power output by the generator, including forced output during short emergency operation, modes of operation are also possible in which it is necessary to consume this power. Examples are as follows: when transmitting electric power along long lines, when transferring local electric supply networks from overhead lines to cable lines, when there is a considerable periodic variation over time of the active power consumed from the network, and in order to reduce thermal loads on the elements in the end zone in parallel with the working synchronous turbogenerators. One of the means of eliminating both the deficiency and the excess of reactive power is to establish electrical-machine reactive power compensators at the network junctions, which provide regulation of the reactive power over a wide range.Electrical machine compensators, unlike static compensators, based on modern power electronics, do not introduce distortions into the current and voltage curves of the system and improve the dynamic processes in the network due to the effect of the rotating masses of the compensator. Electrical machine compensators enable one to increase the production of reactive power under dynamic conditions briefly up to twice the nominal value.The nominal power of a synchronous compensator is determined by the value of the maximum possible reactive power that can be produced by the compensator over a long period. The limiting consumed reactive power for a salientpole synchronous compensator when there is no possibility of negative excitation is about 50% of the reactive power produced by the compensator and does not exceed 80 -85% of the power produced when there is a compensator in the system with possible negative excitation. These relations are even less for a nonsalient-pole synchronous compensator. Hence, up to the present time salient-pole synchronous compensators have been used in practice.The application of modern principles of asynchronous control of synchronous machines to electrical machine compensators [1 -3] enables the compensator to operate in its nonsalient-pole form when the limiting values of the produced and consumed reactive power are equal. For this to occur the compensator mu...

The use of flywheel asynchronized compensators in a power system

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The excitation control system of the ASK-100-4 asynchronous compensator

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