Compensation device with adjustment of reactive power capacity by autotransformer

Abstract

The invention relates to the reactive power compensation technology in a power grid and especially relates to a compensation device with the adjustment of a reactive power capacity by an autotransformer. The device comprises a switching selection switch K and an on-load tap-changer Tf. The autotransformer comprises a main winding and a voltage regulating winding. The voltage regulating winding whose number of turns is NT is independent of the nonadjustable main winding whose number of turns is NG. By using the mutual relation of the two windings, the same polarity direction access and reverse polarity direction access of the voltage regulating winding are realized through the switching selection switch K, thus the rated voltage UBe of the autotransformer can be matched with capacitor rated voltage UCe specified in national standards and industry standards, the ability of adjusting reactive power can reach required 6 to 7, at the same time even in a condition of same autotransformer capacity SBe and capacity adjustment ability M, the autotransformer electromagnetic capacity of the invention is only a half of that in a scheme in the prior art, the corresponding investment cost also can be reduced by nearly a half, thus the economic performance is closer to a fixed grouping method, the technical performance is better than that of fixed grouping method, the service life is longer, and the overall performance is greatly improved.

Description

technical field [0001] The invention relates to an on-site reactive power compensation technology in a power grid, in particular to a compensation device for adjusting reactive capacity of an autotransformer. Background technique [0002] With the increase of grid capacity, the demand for reactive power compensation capacity of the grid is also increasing day by day. Reactive power supply, like active power supply, is an indispensable part to ensure power system power quality, voltage quality, reduce network loss and safe operation. In the power system, the reactive power must be kept in balance. When the capacitive reactive power is insufficient, the system voltage will drop, the power factor of the network will decrease, and the electrical equipment will not be fully utilized, resulting in a decrease in network transmission capacity and increased loss. In severe cases, it will cause equipment damage and the system will be disconnected. Solving the problem of capacitive r...

AI Technical Summary

Problems solved by technology

where S Be is the rated capacity of the autotransformer, which is equal to the maximum reactive power compensation capacity S M , the S Be The capacity S transmitted directly by the autotransformer circuit d And the electromagnetic capacity S transmitted by the electromagnetic induction of the autotransformer m It consists of two parts, namely S Be = S d +S m , Because the cost of the autotransformer depends on the electromagnetic capacity S m , S m The smaller the value, the better the economy, which is just opposite to the requirement of M value, for example, M=2.8, K=1.67, Take the unit price A of the transformer b (10,000 yuan / Mvar) is about three times the unit price of the capacitor bank Ac (10,000 yuan / Mvar), then Acb=(1+0.4×3)Ac=2.2Ac, similarly, if M=7, then Acb=2.87Ac , that is, under the same maximum reactive power compensation capacity, the cost of using a group of capacitor banks with autotransformer capacity adjustment is 1.2 times and 1.87 times higher than that of conventional capacitor banks. Therefore, the existing autotransformer on-load voltage regulation It is difficult to meet the technical requirements and economic requirements at the same time

Images