SU1721644A1 - Electric induction device - Google Patents

Abstract

The invention relates to electrical engineering, namely to high-voltage power transformers and reactors. The purpose of the invention is to improve the voltage class and power due to the uniform distribution of overvoltages across the coils of the winding, improved cooling and full leveling of the electric field in the insulating gap. Between the high voltage winding 1 and the low voltage node 2, an insulating gap 3 is made of tightly fitting layers 4 of solid insulation and capacitive plates 5. Moreover, the height of the layers of solid insulation and capacitive plates on the side of the neutral end 9 of the winding 1 decreases stepwise in the direction the high voltage windings so that between the inner surface of the high voltage winding and the solid insulation steps there forms a free cavity for the circulation of the liquid insulation. 3 il. ; yo

Description

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The invention relates to electrical engineering, in particular to high-voltage power electrical induction devices, such as high-voltage power transformers and reactors.

An electrical induction device (transformer) is known that contains a high voltage winding (HV) in the form of a stack of series-connected coils with linear and neutral leads and simultaneous ends at the extreme coils, a lower voltage node (LV), for example, a magnetic core or a low-voltage winding, insulating the gap between them is from layers of solid insulation with channels of liquid insulation ..

The disadvantage of such a device is its large mass and dimensions due to the increased size of the insulating gap, since the voltage acts mainly on liquid insulation channels with low electrical strength, and the layers of solid insulation with increased electrical strength are low. .

An electrical induction device is known, in particular a transformer containing coaxially arranged HV coil windings with linear and neutral leads and ends at the extreme coils, an LV assembly, for example, a magnetic core or an LV winding, an insulating gap between them from closely adjacent solid insulation layers and capacitive The bone plates, with the ends of the layers of solid insulation and the plates step-likely protrude beyond the limits of the linear end of the high-voltage winding, so that their protrusions increase as the layers are removed from the high-voltage winding.

A disadvantage of the known induction device is that it cannot be used for very high voltage classes 110-750 kV and high power. Its voltage class is limited by the nonlinear distribution of overvoltages across the coils due to the large capacity of the insulating gap made up of closely adjacent layers of solid insulation and capacitive plates, which leads to the breakdown of longitudinal cross-roll insulation. Its power is limited by the lack of circulation of liquid insulation in the insulating gap, which leads to overheating of the coils with increasing current in them.

 The aim of the invention is to increase the voltage class and power due to the uniform distribution of overvoltages across the winding coils, due to improved cooling and due to the complete alignment of the electric field in the insulating gap.

The goal is achieved in an electric induction device, preferably a transformer, containing a high voltage coil winding coaxially arranged in liquid insulation with linear and neutral leads

0 vi with the ends at the extreme coils, the HH node, the insulating gap between them from tightly fitting layers of solid insulation and capacitive plates, and the ends of the layers of solid insulation and the plates of the step5 protrude beyond the linear end of the winding so that the protrusions increase as you remove layers from the winding, due to the fact that the height of the layers of solid insulation and capacitive plates from the side of the neutral ends of the winding is stepwise reduced in the direction of the high voltage winding so that between the inner surface of the high voltage winding and steps solid insulation and capacitive plates form an empty cavity for the circulation of liquid insulation.

This technical solution allows the induction device to be manufactured at a high voltage class of 110-750 kV and higher power (100 MV-A or more) due to the uniform distribution of overvoltage across the winding coils, due to improved cooling and due to complete leveling of the electric field in the isolation gap.

FIG. Figures 1 and 2 show the proposed electric induction device with linear and neutral ends on the edges of the high voltage winding; in fig. 3 - the same, option with

0 with two neutral ends of the HV winding at the edges there is no linear end of the winding HH).

An electrical induction device, a predominant transformer, contains a 1 HV winding, for example 110 kV, a 2 HH coaxially located node, for example, a magnetic core or H. W. 6 layers of solid insulation 4 and plates 5 stepwise protrude beyond the linear end with linear output A of winding 1 so that the projections of the ends b above

5, the end 7 increases as the layers 4 are removed from the winding 1, the opposite ends 8, t, e, the height of the solid insulation layers 4 and the capacitive plates 5 on the side of the neutral end 9 with a neutral terminal X, the windings 1 decrease in steps

the direction of this winding is so. that a free cavity 10 is formed between the inner surface of the winding 1 and the steps of the solid insulation 4 and the plates 5, which, together with the channel 11 and the inter-batten channels 12, form a path for the circulation of the liquid insulation.

In the embodiment of FIG. 1 there is an insulation 13 between the linear end 7 of the winding 1 and an opposed grounded plate 14. This insulation is reinforced by a barrier 15. In the embodiment of FIG. 2, a similar insulation is also present at the neutral end 9; it includes a shaped barrier 15. In the embodiment of FIG. 3 such insulation is absent, since this variant of the winding HH consists of two parallel windings (Fig. 1), and the insulating gap 3 is made equally from both neutral ends. Here, the capacitor plate closest to winding 1 is connected by connecting 16 to line terminal A. In cavity 10, insulating strips are installed to distance and hold the insulation layers.,

The effect of uniform distribution: overvoltages across the coils of winding 1 with an insulating gap 3c with a large capacity (large capacity due to the small size of the gap 3 and its filling with solid insulation with high dielectric constant) is achieved as follows (Fig. 3). An overvoltage wave, a raid on the line terminal A, acts simultaneously on winding 1 and on connection 16 to the nearest capacitive lining. The systems of the plates 5 of the upper and lower ends of the insulation layers form parallel chains of containers and stresses arise on the plates. The dimensions of the plates 5 and their mutual overlaps are chosen so that the voltages on the plates are distributed linearly. In this case, the capacitive current ic through the capacitance C between the coil and the opposing lining is absent, since the potential difference across this capacitance is also absent. On the coils of winding 1, a linear distribution of overvoltages is established, since the capacitive current from the coils to the ground practically does not leak. The current to earth flows only from the linear output A through connection 16 and further through the cladding systems. Reducing the size of gap 3 and filling it with solid insulation layers leads to an increase in the capacitance of this gap, but this does not increase the capacitive current from the winding coils to ground. Filling the gap

3 layers of solid insulation 4 leads to an increase in the electrical strength of the gap and the complete alignment of the electric field in this gap, but

5, the formation of cavity 10 simultaneously provides an efficient circulation of coolant and cooling of the winding, while the voltage across the cavity is practically absent (capacitance C is

10 cavity capacity).

Thus, a technical contradiction between electrical strength and cooling, between reducing the size of the insulating gap 3 and the distribution of overvoltages in winding 1 was solved.

int.

The proposed technical solution makes it possible to reduce by 1.2-2 times the size of the gap 3, to reduce by 1.1-1.3 times the dimensions.

0 energy loss and the mass of the electric induction device. It allows the device to be designed for voltage classes of 110-750 kV and at a capacity of 100 MB-A or more.

The projected reduction in total costs per unit of power allows recouping the cost of a new winding technology in 2-3 years.

Claims (1)

The invention The electric induction device, advantageously a transformer, contains high-voltage coil windings coaxially arranged in liquid insulation with linear and neutral leads and ends at the extreme coils, the lower 5, the insulating gap between them of tightly fitting layers of solid insulation and capacitive plates, with the ends of the layers of solid insulation and the plates stepwise protrude beyond the linear end face of the winding so that the protrusions increase as the layers leave the winding differing from that, in order to increase the voltage class and power due to the uniform distribution of overvoltages across the winding coils due to improved cooling and due to the complete alignment of the electric field in the insulation gap, the height of the layers of solid insulation and capacitive plates with The 0 side of the neutral ends of the winding is reduced in a stepwise manner in the direction of the high voltage winding so that the inner surface of the winding is high. whom stress and steps solid 5, the insulation and the capacitive plates form a free cavity for the circulation of the liquid insulation. .2 ; 8 10 Fig.Z