SU213126A1 - HIGH-VOLTAGE SWITCHING METER - Google Patents

Description

High-voltage switching devices are known, for example, switches containing embedded or separately installed current transformers, the primary winding of which is connected to the power line in series with the switching device, and the secondary windings feed the measuring and protection circuits, and a command unit for controlling the specified switching device located on the ground potential . A command impulse from the ground potential to the control unit of the switching device can be transmitted by means of a mechanical, hydraulic or pneumatic system. The transmission speed of the command pulse in these systems is limited by the speed of propagation of disturbances in the mechanical load, liquid or gas, as well as their inertia. High voltage switching devices are known in which a command pulse is transmitted using a directional concentrated light beam. However, the energy transmitted in this way is not enough to actuate the control organ, and at high potential there must be an additional source of energy, such as a battery with a special charging device, sophisticated electronic equipment and means providing

operation of the device in conditions of outdoor installation.

High-voltage switching devices, in which the devices discussed above are structurally complex for transmitting command pulses, are not reliable enough and at high nominal voltages in most cases do not provide the required speed.

In the proposed switching and measuring apparatus, in order to increase its speed, simplify the design and increase reliability, the current transformer is equipped with additional control windings, one of which is located on the ground potential and connected to the command organ, and the other side is located on the potential of the primary winding of the current transformer and is connected to the control unit of the switching device. In the device the magnetic system of the current transformer is fully or partially used; the insulation between the control windings is the main insulation of the current transformer; and the frequency of the electrical signal from the command body is different from the frequency of the circuit in which the switching device is installed.

On the control windings due to the flow of the current path through the primary winding of the current transformer, a compensating Tpai jjtojJjjWop consisting of the primary current transformer, core and core is applied, and the primary winding is connected in series with the primary winding of the current transformer and one core, and the secondary winding is connected in series with the primary winding of the current transformer, one secondary winding, and the primary winding is connected in series with the primary winding of the current transformer, one secondary winding, and the primary winding is connected in series with the primary winding of the current transformer, one secondary winding, and the secondary winding is connected in series with the primary winding of the current transformer, one secondary winding, the secondary winding is connected in series with the primary winding of the current transformer, one secondary winding sequentially and counter to the control winding of the current transformer, and the other secondary winding is connected to the load, and all windings have the potential of the primary winding of the current transformer.

To reduce the effect on the measuring circuits of the current transformer, the control winding connected to the command organ has a core insulated from the magnetic system of the current transformer, and this core is provided with an additional demagnetizing winding short-circuited to the load. One of the secondary windings simultaneously serves as a control winding, the command signal being fed to this winding through an isolation transformer, the secondary winding of which is connected in series to the secondary circuit of the current transformer.

In terms of its speed, the proposed device significantly surpasses switching devices, where the control signal is transmitted using mechanical, hydraulic or pneumatic systems, and is equivalent to the device, which is controlled by the light signal. At the same time, in its reliability and simplicity of design, it greatly exceeds the known switching devices. The advantages of the proposed switching and measuring apparatus at ultrahigh nominal voltages x 500 kV, 750 kV and more are especially tangible.

FIG. 1 shows a diagram of the proposed switching and measuring apparatus; in fig. 2 is a circuit diagram of a current transformer in which one of the secondary windings is used as the primary control winding; in fig. 3 is a schematic diagram of a current transformer, in which the primary control winding is wound around two cores of a current transformer; in fig. 4 is an electrical diagram of a single-stage current transformer with primary and secondary control windings; in fig. 5 is an electrical diagram of a cascade transformer with primary and secondary control windings; in fig. 6 is a schematic diagram of a current transformer, in which the primary control winding is wound on a separate core, isolated from the magnetic system of a current transformer; in fig. 7 shows a constructive embodiment of a transformer according to the scheme in FIG. 6; in fig. 8 is an electrical circuit of a compensating transformer and its inclusion in the circuit of a switching-measuring apparatus.

The switching metering device contains a switching device /, its control body 2, a current transformer 3, an isolation 4 of the switching device and its control body from the ground potential, a command impulse transmission line 5 from the current transformer to the control body and the device 6, forming control pulse to an electrical signal with carrier

frequency other than the frequency of the circuit in which the high-voltage switching device is installed.

The current transformer contains magnetic cores 7, 8, 9 with secondary windings Ui-I2- wound on them. All cores are covered by the primary winding 10 of the current transformer and the secondary control winding 11. The command signal is fed to the intermediate transformer 12, whose secondary winding UX-YZ is on in series with the Vi-Uz secondary winding on the core 7. Filters 13 are included in the secondary winding circuit for filtering the carrier frequency of the command signal.

The primary control winding may be wound on one or more current transformer cores. FIG. 3, for example, the primary control winding is wound on two cores 7 and 5 with secondary windings. Hi-Hz- The control winding // is under the same potential as the primary winding .772 of the current transformer.

In the case of a cascade transformer, as

One of the possible options, the control winding can be wound on two cores. Then - the primary winding of the lower element of the cascade; Ul-U is the secondary winding of the top element of the cascade; - primary winding of the upper element of the cascade; t / i-Uz is the secondary control winding, which is under one potential with the primary winding of the top element of the cascade.

The primary control winding can be wound on a separate core 14, isolated from the magnetic system of the current transformer - cores 7, 8, 9. All cores with windings are covered by the primary winding 10 and the secondary control winding //. The demagnetizing coil PI-PZ is also wound on the core 14.

In the shown constructive version of the current transformer, all insulation 15 is applied to the secondary windings located in a housing under the potential of a transmission line. Usually, the electric field in the insulation is controlled by capacitor plates. FIG. 7 shows only the outer plate 16, having the potential of the transmission line and the primary winding of the current transformer, the base 17 of the insulating output of the secondary windings 18, made of a metal pipe, the insulation 19 of the secondary winding current transformer and the primary control winding.

FIG. 8 shows the electrical circuit of the compensating transformer 21 and its inclusion in the circuit of the switching-measuring apparatus. As one of the options, a cascade current transformer 22 is shown. The primary winding 23 of the current transformer and the primary winding 24 of the compensating transformer are connected in series. The secondary control winding of the current transformer is connected in series and oppositely with the secondary winding of the compensating transformer / Ci-Kz. In addition, the diagram shows the following elements: 25 — the core of the compensating transformer; 26 - additional winding of the compensating transformer; 27 - load additional winding 26; 28 and 25 — core and secondary winding of the upper stage of a cascade current transformer; 30 - the primary winding of the lower stage of the cascade current transformer.

Thus, the proposed high-voltage switching and measuring apparatus, which contains a switching device with its governing body, is located at a high potential, and a single-stage or cascade current transformer included in power transmission lines in series with a switching device and installed separately from it, or combined with a switching device in one design, the current transformer, besides the purpose of measuring the current in power transmission lines, also serves as a device for transmitting an electrical command signal to the control conductive body.

Subject invention

Claims (4)

1. A high-voltage switching-measuring apparatus containing a switching device with its control unit, a high-potential current transformer with a primary winding connected to a power line in series with a switching device and secondary windings feeding a measuring and protection circuit, installed separately or combined with switching device in one design, and the command body The control circuit of said switching device located on the ground potential, characterized in that, in order to increase its speed and reliability of operation and simplify the design, the current transformer is equipped with additional control windings, one of which is located on the ground potential and connected to the command one. body, and another is located at the potential of the primary winding of the current transformer and connected to the governing body of the switching device, with magnetic current transformer system, as insulation between the control windings, the main insulation of the current transformer and the frequency of the electrical signal from the command organ is different from the frequency of the circuit in which the switching and measuring apparatus is installed. 2. The apparatus according to claim 1, characterized in that, in order to compensate for the emf induced at the control windings due to the flow of the line current through the primary winding of the current transformer, a compensating transformer containing the magnetic core, the primary and two secondary windings is applied and moreover, its primary winding is connected in series with the primary winding of the transformer current, one of the secondary windings is connected in series and counter with the control winding of the current transformer, and the other is connected to the load, and all windings have the potential of the primary winding of the transformer current. 3. The apparatus according to claim 1, characterized in that, in order to reduce the effects on the measuring circuits of the current transformer, the control winding is connected to the command body, has a core insulated from the magnetic system of the current transformer, and this core is provided with an additional demagnetizing winding, closed to the load. 4. Apparatus according to paragraphs. 1 and 2, characterized in that that one of the secondary windings of the current transformer serves simultaneously as a control winding, and a command signal is fed to this winding through an isolation transformer, the secondary winding of which is turned on sequentially in the secondary circuit of the current transformer. 1t1 Fig f ;