SU44982A1 - Device for blocking disconnectors - Google Patents

Description

Already known are devices for blocking disconnectors in installations with a double busbar system, consisting of an electromagnet blocking for each of the disconnectors, driven by current transformers included in both branches of the system.

In the proposed device, for the purpose of using only one winding on the blocking electromagnet, the secondary windings of current transformers are connected in parallel or in series, and the windings of blocking electromagnets are included in the resulting circuit.

The proposed device is shown in the drawing, where FIG. illustrates a circuit diagram of electrical connections of a device that protects against disconnectors being disconnected under load when the secondary windings of measuring transformers are connected in series; FIG. 2 - the same with their parallel inclusion; FIG. 3 and 4-construction of the locking disconnector device in two projections; FIG. 5 is a wiring diagram of an electrical device that protects against disconnecting the load; FIG. 6-design locking drive mechanism of the device.,

(235)

The proposed device consists of a device that protects against erroneous switching off of the disconnectors under load, and of a device that protects against the disconnection of the load. These devices provide complete protection against erroneous and incorrect actions with disconnectors.

A device that protects against disconnection of disconnectors under load. Transformers T and Tg of type measuring current transformers are installed on the busbars (busbars) L and from the drip pan (Fig. 1) to separate bus systems. On the knives of the disconnectors, the locking relays (or, rather, the locking electromagnets) - / and P, are powered, receiving power from; the T and T transformers; Transformers T and T are connected in series (Fig. 1) or in parallel (Fig. 2) and from them supply is provided to the locking relays interconnected in series or in parallel. The fixture acts as follows:

1) When the system I disconnector is on, the LS oil tank is turned on, and the system disconnect switch I is turned off, the current flowing through the A branch creates a current in the winding of the RF | 1mator T, which feeds the relay P and I and forces them to pull the cores; therefore, the on / off switch is forbidden and cannot be switched off before the oil boot is not interrupted.

2, With the disconnectors of systems I and I switched on and the oil cooler turned on, OK can flow along both branches. LM The currents in the transformers T and Tg will be directed towards each other and mutually destroyed. Consequently, the P and Pg power relays will not receive and the locks of the disconnectors are released. One of the disconnectors of any system can be freely switched off (both of them are usually not immediately switched off due to the ore of simultaneous shutdown). When one disconnector is turned off, the current in its transformer disappears, and the current of the other transformer immediately disables the disconnector remaining switched on (similar to item 1).

3) When the disconnectors of both branches xl and i are switched on and when the current flows from the first system to the second or vice versa, the currents in the transformers T and T will be summed up, and the relays, receiving power, will lock the disconnectors of the branches an n B, be- turned off until the load current in one of the transformers changes its direction according to l. 2 or completely absent. It should be noted that it is not possible to turn off the disconnectors if the current is branched from one of the branches towards the oil pan and the other branch at the same time.

4. When both disconnectors and the oil tank are on, but when powered only from one bus system, the other system disconnector, although it is not under load, cannot be turned off until the system-wide oil tank is turned on, i.e. so far, the load flow will not flow along both branches in parallel (as in Section 2) or will be completely absent. In this case, the correct and permissible operation is reinsured unnecessarily and for its execution will cause an extra operation with inter-system oil switches.

Structurally transformers Г „Z Tg в. relays P and Pg are very simple

(Fig. 4 and 5) and can be easily adapted and attached to any kind of systems, lux / byp voltage of open n closed installations. Since transformers and relays are directly installed on buses and disconnectors, the connection wiring is laid directly on high voltage buses, and therefore, no special high isolation between the devices and buses is required.

With an ungrounded neutral and connected, together with the drive disconnectors of all three phases, the proposed device should be installed on two phases.

With a grounded neutral and associated disconnectors, installation of the device is required on only one phase. With single pole disconnectors, installation of the device on all phases is required.

The installation and operation of the transformer and the construction of the locking relay do not require any special explanations, since they are from the drawing. The transformer can be easily fitted on tires of any section.

The locking relay can be adapted to rotary two-way disconnectors.

A device that protects against the inclusion of load disconnectors (Fig. 5). A device consists of a conventional electrical interlock with help, and faceplates or other devices, used for signaling, or similar interlocking for oil driers and disconnectors, and from locking up, its relay acting on the disconnecting actuator (Fig. 6). The interlocking involves communication between the disconnectors and its oil switch (part of the circuit in Fig. 6, shown in solid lines), as well as communication between the disconnectors of the feeder and the inter-system oil switch (part of the circuit; shown in Figure 6 with dotted lines mi).

The first connection does not allow switching on the feeder oil pan before the disconnectors of one of the systems are switched on, as well as the oil pan between the two systems before the disconnectors of both systems are switched on.

The effect of this lock is as follows. A DC minus is fed through the oil pan to the switching coil B. K. Plus is fed to the oil switch off coil through the plate of the disconnectors of one system and then the other. At the inter-system oil tank, the minus goes the same way, and the plus is fed in parallel through the faceplates of the disconnectors of both systems. The plates of the disconnectors, with the disconnectors off, close the DC circuit, and the oil faceplates, when the oil position is on, close the circuit of the tripping coil. It follows that the dynamics cannot be switched on until the disconnectors are turned on, and therefore the load of the disconnectors cannot be included. On the feeder, it is enough to turn on the disconnectors of the same system, and on the inter-system oil pan, it is necessary to turn on the disconnectors of both systems and only; after this, the oil pan can be switched on.

The second interlock (the circuit of which is shown by a dotted line) makes it impossible to turn on the feeder disconnectors and connect both P1in systems with the inter-system oil system turned off, i.e. load and separate power supply from individual transformers or transmission lines. Unloading or balancing of the two systems cannot be performed by feeder disconnectors, since an inter-system oil mixer serves for this. The effect of this lock is as follows. The minus of direct current is fed through the faceplate of the inter-system oil to the locking of the drive, connected in parallel. Plus, relays P and P are supplied through the faceplates of the disconnectors in parallel, but so that from the faceplate of the disconnectors of one system, current flows to the relay of the disconnectors of the other system. The faceplate of the non-system oil mixer when it is turned off closes the relay power supply circuit on the minus side. The loose plates close the circuit from the plus side when they are turned on.

It follows that with the disconnec- tors of one bus system turned on, the disconnectors of the second system of the same feeder cannot be switched on, i.e. the systems cannot be connected before the inter-system oil cooler is switched on.

This lock also makes it impossible to put under pressure the second system of tires that is not working with feeder disconnectors, which is not dangerous; blocking in this case is an unnecessary reinsurance and will cause an extra operation, i.e. a shutdown between the system and the system. After turning on the inter-system oil and power on; feeder disconnectors intersystem oil can be turned off again.

The design of the relay locking the drive of the disconnectors in the off position of the disconnectors is very simple and does not present any difficulties in manufacturing. The locking relay is built in under the drive and, acting by the locking dog 1 (Fig. 6) on the swivel washer 2 when the core of the relay 3 is retracted, does not allow the actuator to be turned to switch on the disconnectors. The locking dog moves freely in the guide bar 4, welded or screwed to the drive. The locking pawl and the core of the relay are interconnected by a brass rod screwed into them to prevent the magnetic field of the relay from affecting the pawl and, consequently, the pawl sticking to the cast-iron drive housing.

The subject matter of the invention.

A device for blocking disconnectors in installations with a double busbar system, consisting of a blocking electromagnet, separate for each of the disconnectors and driven from current transformers included in both branches of the system, characterized in that, for the purpose of applying to the booster electromagnet, only one winding, the secondary windings of current transformers are connected in parallel or

Wires of blocking electromagnets are connected in series with willows.

fig 1

but

Srig. 6