RU105087U1 - HIGH VOLTAGE DISTRIBUTION DEVICE FOR NETWORKS WITH HIGH LEVEL OF SHORT CURRENT CURRENTS - Google Patents

Abstract

 1. Switchgear for high voltage networks with a high level of short-circuit currents, containing busbars to which non-linear surge arresters and relay protection units are connected, as well as power lines and transformers (autotransformers) connected through switching devices (switches), characterized in that, in order to reduce the transient recovery voltages and short circuit currents in the connections, additionally contains a chain of sequentially included vacuum controlled arrester, part of which is shunted by a resistor, and nonlinear surge arresters are made of two modules, the connection point of which is connected to the connection point of the resistor to a chain of series-connected vacuum controlled arrester. ! 2. The device according to claim 1, characterized in that a capacitor device is connected in series with the resistor. ! 3. The device according to claim 1, characterized in that a capacitor device is connected in parallel with the resistor. ! 4. The device according to claims 1 to 3, characterized in that the capacitor device is made in the form of a capacitive voltage transformer.

Description

The proposed utility model relates to electrical engineering and can be used in high voltage networks with high short circuit currents.

Known controlled vacuum arresters (RVU), used for high-speed protection of the load against short circuit currents and overvoltage [Alferov DF, Ivanov VP, Sidorov VA Guided vacuum arresters: basic properties and applications // ELECTRO, 2002, No. 2, p.37]. The combination of RVU with vacuum circuit breakers allows to increase the speed of vacuum switching devices, while maintaining their ability to withstand rated currents for a long time.

The disadvantage of this technical solution is the high speed and amplitude of the transient recovery voltage (PVN).

A high-voltage electric network is known in which protection against overvoltages arising when it is turned off by a vacuum circuit breaker is performed using non-linear surge suppressors (arrester) connected between the phase terminals of the electric motor and the ground [RF Patent No. 2110878]. Such installation of protective devices allows to reduce overvoltages to the level of test voltages.

The disadvantage of this technical solution is the limited scope (only in networks with isolated neutral) and the low efficiency of reducing the speed of the arrester.

A known method of reducing the recovery voltage, implemented in a device containing a parallel-connected resistor, capacitor and inductor connected between the busbars and the ground through a switch, and a switch whose turn-on time is less than the turn-off time of the linear switch [Copyright certificate No. 231656]. This invention is adopted as a prototype.

The disadvantage of this technical device is the high level of short circuit currents and the amplitude of the transient recovering voltages.

The purpose of the proposed utility model is to reduce short circuit currents in a damaged connection and the speed and amplitude of transient recovery voltages.

This goal is achieved in that a high voltage switchgear for networks with a high level of short circuit currents, containing busbars to which non-linear surge arresters and relay protection devices are connected, as well as power lines and transformers connected via switching devices (switches) (autotransformers ), additionally contains a chain of series-connected vacuum controlled arresters, some of which are shunted by a resistor, and non-linear e surge arresters are made of two modules, the connection point of which is connected to the connection point of the resistor to a chain of series-connected vacuum controlled arresters; in this case, a capacitor device is connected in series with the resistor; in addition, the capacitor device is connected in parallel with the resistor; wherein the capacitor device is made in the form of a capacitive voltage transformer.

Switchgear for high voltage networks with a high level of short circuit currents is shown in figure 1. It contains busbars (1), a non-linear surge suppressor (OPN), consisting of two modules (OPN-2 and OPN-3), a relay protection device (4), and also a power line (6) connected via switches (5), a chain of series-connected arresters of vacuum controlled (RVU-7) and (RVU-8), shunted by a resistor (9), and a control unit (10).

In addition, figure 2 presents the connection diagram of the capacitor device (11) in series with the resistor (9), in figure 3 - parallel to the resistor (9).

In Fig.4, the capacitor device (11) is made in the form of a capacitive voltage transformer (12).

The work of the proposed utility model will be considered on the example of the device shown in figure 1.

To the busbars of the substation (1) through the switches (5) are connected: a power line (6), a relay protection device (4), an arrester consisting of two modules (OPN-2 and OPN-3), RVU-7 and RVU-8 with control unit (10).

The connection point of OPN-2 and OPN-3 is connected to the connection point of RVU-7 and RVU-8, and RVU-8 is shunted by a resistor (9).

In case of a short circuit on one of the connections, for example, a power line (6), the short circuit current exceeds the rated breaking current of the circuit breaker (5). To reduce the current in the damaged circuit and the level of transient recovery voltages at the contacts of the switch (5), a command is sent from the relay protection device (4) to the input of the control unit (10), which sends a signal to the controlled electrodes of RVU-7 and RVU-8. As a result, the RVU-7 and RVU-8 are triggered and the busbars (1) are grounded. A short circuit on the power line (6) is bypassed, and the short-circuit feed current through the switch (5) is reduced, depending on the arc resistance and the distance of the short circuit from the busbars of the substation (1), by 80-100%. After a time sufficient to reduce the current in the circuit of the switch (5) of the power line (6), a command is issued to turn it off. After the circuit breaker (5) is turned off, a command is issued to disconnect the RVU-8, while the speed and amplitude of the transient recovery voltages is limited by the action of the resistor (9) and the arrester-3, which ensures its reliable shutdown, after which a command is sent to the RVU-7, busbars (1) ground and the circuit returns to its original position.

The presence of a capacitor device (11) ensures reliable switching of the RVU-7 and RVU-8 during short circuits (metal short circuits) in the immediate vicinity of busbars (1).

The installation of a chain of highly linear resistors allows you to distribute the voltage to the RVU-7 and RVU-8 and at different times off, as well as to charge the capacitor (11) in normal mode until a short circuit occurs.

Claims (4)

1. Switchgear for high voltage networks with a high level of short-circuit currents, containing busbars to which non-linear surge arresters and relay protection units are connected, as well as power lines and transformers (autotransformers) connected through switching devices (switches), characterized in that, in order to reduce the transient recovery voltages and short circuit currents in the connections, additionally contains a chain of sequentially included vacuum controlled dischargers, some of which are shunted by a resistor, and nonlinear surge arresters are made of two modules, the connection point of which is connected to the connection point of the resistor to a chain of series-connected vacuum controlled dischargers. 2. The device according to claim 1, characterized in that a capacitor device is connected in series with the resistor. 3. The device according to claim 1, characterized in that a capacitor device is connected in parallel with the resistor. 4. The device according to claims 1 to 3, characterized in that the capacitor device is made in the form of a capacitive voltage transformer.