RU113869U1 - TRANSVERSE CAPACITY COMPENSATION DEVICE IN AC TRACING NETWORK - Google Patents

Abstract

A device for lateral capacitive compensation in an AC traction network, containing a series-connected bus disconnector with a motor drive, the first and second switches, a capacitor bank and a reactor connected to the rail, as well as a damping resistor, the first terminal is connected to the connection point of the second switch with a capacitor bank, which differs the fact that a short-circuit breaker and a high-voltage fuse with two output contacts are introduced, and the short-circuit breaker is connected between the rail and the junction point of the bus disconnector with the first switch, and the high-voltage fuse is connected by the first output contact to the second output of the damping resistor, and the second output contact is connected to the junction point of the first and second switches.

Description

The utility model relates to the power supply of electric railways of alternating current, in particular, to the protection of single-phase transverse compensation systems in the traction network.

A device for lateral capacitive compensation in the traction AC network (KU), containing serially connected bus disconnector with a motor drive, the first and second switches, a capacitor bank and a reactor connected to the rail, a damping resistor is connected in parallel with the second switch [1, Fig. 68] .

The disadvantage of the circuit. When KU is turned on at the end of the section of the traction network with one-way power supply, there is no device for redundant failure of the first circuit breaker (URO). The option to turn on the KU in the area with one-way power is shown in [2].

The purpose of the utility model is to increase the reliability of the KU due to the introduction of the device URO.

To implement the transverse capacitive compensation indicated in the device in an alternating current traction network containing a busbar disconnector with a motor drive connected in series, the first and second switches, a capacitor bank and a reactor connected to the rail, as well as a damping resistor with the first output connected to the connection point of the second switch with capacitor bank, a short-circuit and high-voltage fuse with two output contacts are introduced, and a short-circuit is connected between the rail and the connection point of the bus disconnector with the first switch, and the high-voltage fuse with the first output contact is connected to the second terminal of the damping resistor, and the second output contact is connected to the connection point of the first and second switches.

In this case, for the first circuit breaker, the CBR is carried out using a short-circuit, and to reduce the number of cases when the short-circuit is activated, in which a short circuit occurs on the contact network, an additional high-voltage fuse is also included.

The scheme of the utility model is presented in the figure, which shows:

1 - busbar disconnector with motor drive;

2 - short circuit;

3 - the first switch;

4 - second switch;

5 - high voltage fuse;

6 - damping resistor;

7 - capacitor bank;

8 - reactor;

9 - rail.

The scheme works as follows. The control unit is connected to 27.5 kV buses, which are connected to the contact network.

The initial state of the switches when the switchgear is on: the first 3 and second 8 switches are on.

In case of damage to the control unit, its protection acts on the tripping of the first 3 circuit breakers and upon failure of the protection with a time delay of 1.5 s. affect the inclusion of short circuit 2, which carries out an artificial short circuit (short circuit) on the 27.5 kV buses, that is, on the contact network. A similar situation occurs with the operational shutdown of the switchgear in case of failure of the circuit breaker 3.

As a result, the contact network feeder that feeds the specified switchgear is disconnected (it can be a section post feeder or a traction substation feeder (feeder), not shown on the diagram). In a currentless pause, the bus disconnector with motor drive 1 is disconnected, and then by automatic reclosure in 5 ... 6 s. The early emergency disconnected contact network feeder is switched on.

Thus, when the CBD is operating for 5 ... 6 s, the voltage on the contact network disappears, and the damaged switchgear is disconnected by the bus disconnector 1.

The need for a high-voltage fuse 5 is dictated by the desire to reduce the number of starts of short circuit 2 and the corresponding reduction in cases of power failure by 5 ... 6 sec in the contact network.

During operation of the protections and during operational shutdowns, the command to turn off the first switch 3 is given simultaneously with the command to turn off the second switch 8. But the circuit provides [1] that the first switch 3 is turned off later by 0.1 ... 0.3 s than the second switch 4. Therefore, if there is a failure of the first switch 3, then for up to 1 s. the fuse should trip in accordance with its characteristics [3], (see Appendix), and the damage is localized. If the high-voltage fuse 5 does not work for any reason, then after 1.5 s. a short circuit 2 command is issued.

When the KU is turned on and if the first 3 and second 8 switches fail, the command to turn on short circuit 2 is given 1.5 seconds after the command to turn on the KU.

The rated KU current of 2.7 s is provided for the damping resistor, so the operation delay of the short circuit is 1.5 s. valid.

The technical and economic effect is determined by increasing the reliability of the control unit, since if the circuit breakers fail, there will be no damage to its equipment (capacitors, damping resistor, etc.)

1. Borodulin B.M., German L.A., Nikolaev G.A. Condenser installations of electrified railways.-M.: Transport, 1983-183 p.

2. German L.A. Transverse capacitive compensation in railway traction networks. Industrial Energy No. 10, 2009. P.30-35.

3. Andreev V.A. Relay protection and automation of power supply systems. M .: Higher School, 2008.640 s.

application

1. The source data

1) Damping resistor 6.

Resistance - 80 Ohms.

The maximum accumulation energy at a single start is 4MJ.

When the damping resistance 6 is included in the KU circuit, the KU current is 140 A.

We determine the maximum allowable current flow time of 140 A. The voltage across the resistor is 140 x80 = 11200 V.

Power loss in the resistor for 1 second:

140x11200x1 = 1568000 J = 1.57 MJ.

Then the permissible operating time of the damping resistor under current is 4 / 1.57 = 2.7 s.

2) Input data for fuse 5.

We use a fused circuit breaker with a voltage of 35 kV.

Fuse-link for current 20A: its characteristic - see [3, Fig.4.4].

At a current of 140 A, the insert burns out in 0.5 ... 1 s.

Despite the rated current KU - 160A, we accept the rated current of the fusible insert - 20A. This is because the damping resistor 6 with fuse 5 is switched on for a short time - for 0.1 ... 0.3 s

2. Analysis of the operation of the device UROV.

2.1. Disable KU. Switch 3 trips after 0.1 ... 0.3 s. after turning off the switch 8. If both switches are working normally, then the fuse 5 will not blow.

If switch 8 does not open, then all the same, after 0.1 ... 0.3 s, switch 3 will open.

If switch 3 does not open, then fuse 5 should trip after 0.5 ... 1 s.

2.2. Turn on KU. The switch 8 is turned on after 0.1 ... 0.3 s. after turning on the switch 3. If both switches are working properly, then fuse 5 will not blow.

If switch 8 does not turn on, then after 0.5 s. a command is given to trip the switch 3.

In case of failure of circuit breaker 3 when switching off the switchgear, as well as in the case of failure of switches 3 and 8 when turning on the switchgear, the CBR starts in 1.5 s after switching on (disconnecting) the switchgear.

If, in case of damage to the switchgear, its current exceeds 4 ... 5 times the nominal value (this is more than 600 ... 800 A), then if switch 3 fails, the command to close the short circuit is reduced to 0.5 s.

Claims (1)

A transverse capacitive compensation device in an AC traction network, comprising a busbar disconnector with a motor drive connected in series, first and second switches, a capacitor bank and a reactor connected to the rail, and a damping resistor with the first output connected to the connection point of the second switch with a capacitor bank, characterized in in that a short-circuit and high-voltage fuse with two output contacts are introduced, and a short-circuit is connected between the rail and the point with busbar disconnector with the first switch, and the high-voltage fuse with the first output contact is connected to the second output of the damping resistor, and the second output contact is connected to the connection point of the first and second switches.