Device for increasing the capacity of a three-phase overhead power line

Abstract

This utility model pertains to electrical engineering, specifically to AC power transmission technology, specifically high-voltage overhead lines. The technical result of this utility model is a reduction in power transmission losses by compensating for (reducing) reactive (inductive) currents, thereby increasing line capacity. The main distinguishing feature of the proposed technical solution is the independence of reactive current generation from grid voltage fluctuations. The innovative nature of the proposed technical solution lies in its ability to automatically determine the optimal operating conditions for the power line and generate the necessary responses to changes in grid characteristics. 1 fig.

Description

[0001] The utility model relates to the field of electrical engineering, in particular to the technology of transmitting electric power by alternating current, namely to high-voltage overhead lines.

[0002] A technical solution is known [1], in which static thyristor compensators are used to increase the line capacity, ensuring an increase in the line capacity due to compensation of inductive reactive currents.

[0003] The disadvantage of the analog is the dependence of the degree of compensation on the square of the voltage on the power transmission line.

[0004] A device for increasing the transmission capacity of long-distance power transmission [2] is known. The essence of this device is that mutual induction elements (transformers) are constantly connected in a counter-current circuit in the middle section of the line, in pairs between all phases, to compensate for the inductive reactance of the line. This device was selected as a prototype.

[0005] The disadvantage of the prototype is the relatively high power transmission losses, which reduces the line capacity.

[0006] The technical problem solved by the utility model is the reduction of electrical power transmission losses by compensating (reducing) reactive (inductive) currents and, consequently, increasing the line capacity.

[0007] The specified technical problem is solved as follows: the secondary windings of two transformers are included in the section of the power transmission line, wherein the first transformer has one winding included in the section of the first phase, and the second has two windings included in the section of the two remaining phases, the primary winding of the first transformer is connected to the output terminals of the magnetic amplifier, and the second - to the input terminals of this magnetic amplifier; the control terminals of the magnetic amplifier are connected to the output of the computing unit, the input of which is connected to the current and voltage sensors of the first phase.

[0008] The significant differences of the proposed utility model are the reduction of reactive currents, due to which the losses of electric power transmission are reduced and the capacity of the line is increased.

[0009] This is a set of essential features that ensures the achievement of a technical result in all cases covered by the requested scope of legal protection.

[0010] The applicant has not identified any sources containing information on technical solutions whose combination of features coincides with the combination of distinctive features of the claimed utility model, which allows us to conclude that it meets the criterion of "novelty".

[0011] Due to the implementation of the distinctive features of the utility model in the proposed technical solution, it is possible to reduce power transmission losses and ensure an increase in the line capacity.

[0012] Individual distinguishing features of the claimed utility model are known from other technical devices; however, the applicant is unaware of any publications containing information on the use of auxiliary transformers to generate orthogonal current vectors (reactive). Therefore, in the applicant's opinion, it can be concluded that the claimed technical solution meets the criterion of "inventive step."

[0013] The circuit diagram for implementing the proposed device in a single-phase design, i.e., reactive current compensation is performed only in phase A, is shown in Fig. 1. The device comprises: 1, 2 transformers; the secondary winding of the first is included in the section of phase A, and two secondary windings of the second transformer, respectively, in the sections of phases B and C, 3 a magnetic amplifier, the output terminals of which are connected to the primary winding of the first transformer, and the input terminals of the magnetic amplifier are connected to the primary winding of the second transformer, the control terminals of the magnetic amplifier are connected to the output of the computing unit 4, the input terminals of which are connected to the output terminals of the current sensors 5 and voltage 6 of phase A.

[0014] Let's consider the operation of the device. Assume that symmetrical, actively inductive currents flow in three phases of the line. Their power factor is determined by the parameters of the line and its load. In this case, an EMF proportional to the line voltage U is induced in the secondary winding of transformer 2. BC . Voltage vector orthogonal to the phase voltage vector . Using transformer 1 and magnetic amplifier 3, vector summation of linear vectors is performed and phase stresses.

[0015] The phasing of the primary windings of transformer 2 and magnetic amplifier 3 is selected in such a way that the result is a difference between the voltage vector of phase A and a vector proportional to the voltage vector To ensure the equality of these currents and, accordingly, to ensure that the vector sum is zero, the value of the reactive current of phase A is obtained in the computing unit 4 by processing the values ​​of the current and voltage of phase A from sensors 5 and 6. Then, the value of the control current of the magnetic amplifier 3 is calculated. The correction of the control current is carried out until the reactive current of phase A becomes equal to zero; in this case, natural power will flow along the line.

[0016] Sources of information taken into account when preparing the description of the application: 1. “Strong Networks” based on FACTS [Electronic resource]. - Access mode: https: / / studme.org / 138522 / tehnika / silnye_seti_baze_facts (date of access 03.01.2025).

[0017] 2. Russian Federation Patent 2 726 174C1, H02J 3 / 20, 2020.07.09.

Claims

A device for increasing the transmission capacity of a three-phase overhead power transmission line, comprising two transformers, characterized in that the first transformer comprises one primary and one secondary winding, and the second - two primary and one secondary winding, wherein the secondary winding of the first transformer is included in the section of the first phase, the primary windings of the second transformer are included in the sections of the other two phases, a magnetic amplifier, a computing unit, and first phase current and voltage sensors are additionally introduced, wherein the secondary winding of the second transformer is connected to the input of the magnetic amplifier, and the primary winding of the first transformer - to its output, the control input of the magnetic amplifier is connected to the output of the computing unit, and its input is connected to the current and voltage sensors of the first phase.

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