SU920679A1 - Device for stabilizing strength of electrical equipment current conductor magnetic field - Google Patents

Description

The invention relates to electrical engineering and can be used in devices for compensating the alternating magnetic fields of multiphase electrical equipment conductors.

A device is known for stabilizing the magnetic field strength of electrical equipment conductors, which contains a three-winding current transformer, the primary winding of which is connected to the main electrical equipment circuit, the secondary winding to the compensation coil, and the auxiliary winding connected to the output of the amplifier, whose input is connected to the primary converter. Such a device provides a high compensation efficiency of the magnetic field of dispersion 1,

However, in this scheme, a three-winding current transformer is used, which somewhat complicates the implementation of the device, since usually two-winding measuring current transformers a 1 are manufactured by industry.

The closest technical solution to the invention is a device for stabilizing the magnetic field of conductors

electrical equipment containing current transformers, the primary windings of which are connected to the conductors of the main electrical equipment chain, a compensation coil and an amplifier, to the input of which is connected a primary induction converter C2.

A disadvantage of the known device is the complexity, since in a p-phase power system, a p-1 device is needed, which increases the number of elements in the circuit, the weight, the dimensions of the stabilization system. Besides,

15, when at least one element of the feedback circuit fails, the field is completely disturbed.

The aim of the invention is to simplify the device.

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Claims (1)

This goal is achieved by the fact that in the device for stabilizing the magnetic field strength of electrical equipment conductors containing current transformers, the primary windings of which are connected to the conductors of the electrical equipment main circuit, the compensation coil and the amplifier to which the primary induction converter is connected, the secondary windings of transformers. current are connected to each other in parallel and connected to the compensation coil, and the output of the amplifier is connected in parallel to the compensation coil. The drawing shows an electrical circuit diagram of the device. The primary windings of current transformers 1 and 2 are included in phases A and C of the main circuit of the switchboard. The secondary windings of transformers 1 and 2 are interconnected in parallel and connected to the compensation coil 3 to which the output of amplifier 4 is connected. To the input of amplifier 4 the primary induction is connected transducer 5. To reduce the mutual influence, the compensation coil 3 and the primary induction transducer 5 are made in the form of loop windings laid along the perimeter of the shield in parallel planes. The primary coils of transformers 1 and 2 consist of one or several turns of a relatively large cross section and are connected in series to the electrical circuits of phases A and C, the secondary windings of transformers 1 and 2 on the contrary consist of a large number of turns of a relatively small cross section. The device operates as follows . When power is applied to the main circuit through a compensation coil, the resulting current of phases A and C flows. Primary induction converter 5, which is a measuring winding, converts the difference signal induced in it between the source field of the conductor of the shield and the system field Current transformers - reverse compensation coil connection arriving at the input of the amplifier 4. The input of the amplifier 4 must have electrical characteristics that provide the conditions for optimal matching of the primary converter l 5 and the input impedance of the amplifier 4. Thus, the stabilizing circuit performs a flexible negative feedback. in deflecting the voltage of the field of the compensation coil 3, the feedback current must be in antiphase with a compensation current proportional to the resultant current, and reduce the current in the compensation coil. Once the magnetic field j of the switchboard junction of the switchboard, which is of a random nature, results in an additional error. The problem of a stabilizing loop is such a degree of compensation of the spread of the field, at which the required accuracy of compensation is ensured. Obviously, the non-primary field transducer should cause the system to react in such a way that the change in the compensated magnetic field was less than a predetermined value, for example, the required magnetic field level or the measurement system error. Thus, the proposed stabilization system circuit by parallel connection of the secondary windings of current transformers allows reducing the number of compensation coils, amplifiers and primary converters. In addition, this device allows to reduce the power of the amplifier, since part of the power through current transformers comes directly through the main circuit of electrical equipment. Apparatus of the Invention A device for stabilizing the magnetic field strength of electrical equipment conductors, comprising current transformers, the primary windings of which are connected to the conductors of the electrical equipment main circuit, a compensation coil and an amplifier, to the input of which a primary induction converter is connected, in order to simplify the device, the secondary windings of current transformers are interconnected in parallel and connected to the compensation coil, and the amplifier output is connected parallel to the compensation coil. Sources of information taken into account in the examination 1., USSR Author's Certificate for Application 2722561 / 24-07, cl. G 05 F 7/00, 1979, 2 “USSR Copyright Certificate for Application No. 2729368 / 24-07, cl. G 05 F 7/00, 1979.