Drives for high voltage switchgear

Special devices are used to turn on and off disconnectors, load break switches, oil switches and other switching equipment — drive… For automatically tripped or turned on devices drive unit keeps them in the on or off position respectively.

According to the nature of the energy used, drives are divided into manual, electric (electromagnetic, electric), spring, pneumatic. Previously, cargo drives were used, which turned out to be insufficiently reliable in operation.

Also distinguish between non-automatic, semi-automatic and automatic drives. The first ones allow turning the device on or off only manually. The latter provide automatic (remote) shutdown or, in some cases, turning on the device. Automatic drives allow automatic (by appropriate protection and automation devices) or remote switching devices on and off.

For driving disconnectors the most commonly used manual lever drive. It can be installed in both closed and open switchgear. The handle of such a drive moves in a vertical plane at an angle of 120 — 150 °. The movement of the handle by means of rods and levers is transmitted to the knife shaft of the disconnector. When turned off, the handle of the drive is turned down, when turned on - from the bottom up.

The manual actuators are installed on the same support structures on which the disconnector is located. The presence of an actuator allows for mechanical or electrical interlocking of the disconnector and circuit breaker to prevent improper operation of the disconnector when the circuit breaker is closed.

Single-pole disconnectors are often operated with an insulating rod that captures a loop specifically provided on the disconnector blade.

Short circuits and separators are controlled by devices such as PG-10K and PG-10-0 or SHPK and SHPO. These drives, which have the same kinematic diagram, are housed in external cabinets. The shaft of these drives by means of suitable levers andG connected by short-circuits or spacers.

The short circuit drive can accommodate two overload current relays and one trip solenoid. When actuated, a relay or solenoid is released, the drive lock and the short circuit are turned on under the action of the spring disconnection input.

Manually turn off the short circuit breaker using the drive control handle.A cut-off electromagnet is installed in the drive of the separator, which, when actuated, also releases the lock and provides automatic shutdown of the separator under the action of the wound when the spring is engaged. Previously, special blocking relays (BRO) were installed in these devices, but they turned out to be insufficiently reliable, and therefore, in order to prevent the disconnection of the separator when the short-circuit breaker is turned on, use current blocking in the automatic control circuit.

Load break switches can be equipped with drives with several modifications: with manual on and off (type PR-17), with manual on and manual or remote off (type PRA-17), with remote or automatic on and off ( type PE-11).

Load-break switches with earthing blades are operated by a separate, manual actuator with a mechanical interlock that prevents the earthing blades from being engaged when the switch is closed.

Actuators are used to control oil and other switches that have the following basic components: a switch mechanism that ensures the switch is closed, a locking mechanism (lock) that holds the switch in the closed position, and a release mechanism that releases the lock, then the breaker is opened by the opening springs engaged when closed. When switching on, the greatest effort is required, since in this case it is also necessary to overcome the resistance of the opening springs. Friction and inertial forces in moving parts. When switched on for a short circuit. may need overcoming electrodynamic effortspushing the contacts apart.

Mostly for management switches use automatic drives. Spring drives are the most widespread in rural electrical networks. | More ▼ their widespread use compared to electromagnetic drives is explained by the fact that their operation does not require rechargeable batteries and corresponding chargers. In this case, the switch closes automatically under the action of pre-wound (tensioned) springs.

Closing springs can be wound manually or with a special motor, which is usually equipped with a gearbox (automatic gear motor - AMP). Spring drives are used to control the voltage of oil circuit breakers 6 — 35 kV. They provide: manual or remote (by means of built-in on and off electromagnets) switching on and off of the circuit breaker, automatic opening of the circuit breaker under the action of protection (using built-in relays or a separate set of protective relays), automatic reclosing (AR) of the circuit breaker after the automatic its opening by a special relay circuit and a built-in switching electromagnet (mechanical automatic reclosing is also possible using a lever mechanism of the drive, which is not usually used recently).

Available in various spring drive designs (such as PPM-10, PP-67, PP-74, etc.). In rural electrical networks, the most commonly used drive is the PP-67K type.

Experience with the operation of spring drives, in particular of the PP-67 type, has shown that they fail relatively often and, due to the complex mechanical part, are one of the most unreliable elements of electrical equipment. That is why there are several designs, in particular electromagnetic drives, using powerful rectifiers for rural electrical installations.

Electromagnetic drives, powered by rechargeable batteries, are widely used in installations with constant current operation. These actuators are direct-acting circuit breaker controls: the energy required for closing is supplied directly during closing from a high-power source to the switching solenoid. The interruption occurs under the action of a low-power tripping solenoid. The advantage of electromagnetic drives is the simplicity of design and reliability of operation. The main disadvantage is the large current consumed by the switching electromagnet.

The industry produces several types of electromagnetic drives. For 10 kV circuit breakers, PE-11 type drives are widely used.

Most of the different types of drives are equipped with a free release device. It is a mechanical drive unit that allows the breaker to be tripped freely from the position of the moving elements. The free tripping device is especially necessary for the quick opening of the circuit breaker. when you short circuit it.

Compressor powered air switches are operated pneumatically. The action of this drive is provided by the energy of compressed air from the same compressor unit.