SU792312A1 - Cascade-type current transformer - Google Patents

Description

The oTHocHtt: fl image is applied to devices for measuring current in high voltage installations and can be applied to various electric power facilities. Known current transformers including cascade transformers used in high-voltage installations. Known cascade current transformer containing cores of the lower and lower stages with primary, secondary and intermediate windings and with an amplifier connected to shunts in the secondary circuit of the lower stage, an additional core with primary and secondary windings and an additional amplifier 1. The disadvantage of this device is with the complexity of the circuit, which leads to low reliability of the current transformer as a whole ... The current transformer, containing toroidal cores with windings and an additional power amplifier with phase-sensitive output 21. The current transformer containing the primary winding, ferromagnetic ring core and secondary windings is also brightened, its primary winding being made in the form of a rigid loop located in the core window so that the primary winding plane passes through the middle according to the included secondary windings located symmetrically on opposite sides of the core, and between the branches of the primary winding in the core window there is an additional rectangular ferromagnetic with Cardiac Gz. The drawbacks of the device are the design complexity and the difficulty of uniformly adjusting the gap of the additional rectangular core. The closest in technical essence of the present invention is a cascade current transformer containing two cores with a primary and

secondary windings on each of them, and to increase accuracy and reduce the number of turns, the secondary winding of the first cascade and the primary winding of the second cascade are made of parallel branches of different sections connected in series, and the windings of the primary winding of the second cascade include 1 opposite f4j.

The disadvantage of this cascade transformer is the double number of turns of the secondary winding of the first cascade and the primary winding of the second cascade, which complicates the design and increases its cost.

The aim of the invention is to eliminate these disadvantages while maintaining the same accuracy.

The goal is achieved by reducing the number of windings of a cascade current transformer by using the secondary winding of the first cascade as the primary winding of the second cascade.

The drawing shows a cascade current transformer.

The primary winding of the first cascade I is covered by an i-toroidal or rectangular core 2 of the first cascade on which the secondary winding 3 of the first cascade is located is short-circuited. , Toroidal or: a rectangular core 4 of the second cascade with a secondary winding 5 located on it covers the core 2 of the first cascade. A load 6 is connected to the secondary winding 5 of the second cascade.

Thus, the secondary winding 3 of the first stage is at the same time the primary winding for the second stage. At the same time, the number of turns of the primary winding of the second jascade will be equal to one with one layer (stroke) of the winding 3 equal to two with two layers (strokes) of winding 3, etc. It is clear that with such a scheme, the resulting load of the cascade current transformer, other conditions being equal, is less than that of

Ordinary, by eliminating one of the windings (three windings instead of the usual four).

At the same time, due to the absence of resistance of the primary winding of the second load cascade, the current transformer offered is lower and, consequently, the accuracy is higher. To increase the accuracy of the proposed device in transient conditions, one of the cores (core 2; or core 4) or both may have air gaps.

The application of the proposed device reduces the cost of cascade current transformers and improves the accuracy of their work.

Claims (4)

1. A cascade current transformer containing two ferromagnetic cores with primary and secondary windings on each of them different in that, in order to simplify the design and increase the accuracy / core of the second cascade, pass the first cascade core, so that the secondary winding of the first cascade is the primary winding of the rogoro cascade. 2. Transformer by li. 1, which is based on the fact that one of the cores of the cores is made with a gap. - 3. A transformer according to claim I, about tl and - wishing t & l that both cores are filled with a gap. Sources of information taken into account in the examination 1.Authorical Childhood of the USSR No. 603009, cl. And O1 F 4O / 06, 1976. 2. USSR author's certificate M 307520, class H 01 F 19/00, 1969. 3. USSR author's certificate N 5O4254, class H 01, 1973. 4. USSR author's certificate number 496612, cl. H 01 F 4O / 06, 1973.