RU87967U1 - DEVICE FOR DETERMINING THE TERMINATION OF INSULATED WIRES OF AIR LINES WITH A VOLTAGE OVER 1000V AT THEIR LOCATION ON THE BRACKETS OF THE CONTACT AC NETWORK IN THE ZONES OF APPROXIMATION WITH HIGH VOLT POWER LINES - Google Patents

Abstract

A device for determining the breakage of insulated wires of overhead lines with voltages exceeding 1000 V when they are located on the supports of the contact AC network in the areas of proximity to high-voltage power lines (power lines), consisting of a three-phase supply transformer, the secondary high-voltage winding of which is connected through the switching device to air-insulated wires of a high-voltage lines, at the beginning and end of which transformers are connected, the secondary windings of which are connected in a triangle, and the primary windings connected to a star, the zero points of which are connected to artificial earthing switches through active-capacitive filters, characterized in that in it, in addition to the zero-sequence voltage filter, a threshold voltage element is connected at the end of the line, the output terminals of which are connected to the input terminals of the threshold time element generating the signal to turn off the switching device of the measuring transformer and the trigger element of the filter on-time; at the same time, at the beginning of the line, a threshold voltage element is also connected in parallel with the zero-sequence voltage filter, which supplies a signal to a logic unit, the closure of the output contacts of which leads to disconnection of the switching apparatus of the high-voltage power line with isolated neutral.

Description

The utility model relates to electrical engineering, in particular, to the power supply system for non-traction consumers of electrified railways, and can be used to determine the breakage of overhead lines with voltages above 1000 V with insulated neutral, which have found application for powering non-traction consumers, including communication devices, in case of a break in an air insulated wire.

Known technical solutions for determining the breakage of an air wire in networks with a voltage of more than 1000 V with an isolated neutral, the principle of operation of which is based on the occurrence of voltage (L-1, L-2) or voltage and current (L-3) of zero sequences.

In L-1, a device is proposed for protecting overhead lines from single-phase earth faults of high-voltage lines with voltages above 1000 V for supplying non-traction consumers. It is taken as a prototype.

The prototype consists of a supply transformer, switching device, air wires of a high-voltage line, measuring transformers of the type TM or TS, active-capacitive filters, a threshold voltage element with a given setpoint for a zero sequence voltage, a threshold time element with a given setpoint for a time for a zero sequence voltage size, logical element "And", artificial grounding conductors. The prototype device operates as follows.

In the event of the breakdown of the insulated overhead line of the overhead line located in the zone of electromagnetic influence due to the operating voltage of the supply transformer and the installation at the beginning and end of the line of two active-capacitive filters included in the ground circuit of the zero point of the primary winding of the transformer, the secondary winding of which is connected in a triangle, artificial ground electrode and filter flows zero sequence current. A threshold element is activated that fixes the zero sequence voltage level, and sends a signal to the logic block.

After a predetermined time value exceeding the time for disabling the short circuit mode in the traction network, the threshold time element closes the output contact and also sends a signal to the logic block. Thus, two signals appear at the input of the logic element “AND” - from threshold elements of voltage and time. Next, a signal is sent to turn off the overhead line by the switching device.

In the event that the zero sequence voltage exceeds the threshold element setting due to the magnetic influence of currents in the traction network during short circuits, only the threshold voltage element is triggered. The threshold time element is triggered by the signal of the threshold voltage element, but does not have time to give a signal at its output due to the short duration of this mode (its duration is less than the specified time setting). The signal to turn off the overhead line will not come.

However, the known device cannot be used in cases where the overhead line, in particular a 10 kV overhead line, is located near high-voltage (330 and more kV) power lines, that is, in areas of significant electromagnetic influence. Under such conditions, the device for determining the breakage of overhead lines, the operation of which is based on the appearance of a zero-sequence voltage at the energy source, does not record the occurrence of an emergency mode. Wire breakage away from the power substation can also lead to unreliable operation of the device.

Indeed, due to the electric effect of voltage and the magnetic effect of currents in power lines, zero-sequence voltages arise in the overhead lines of the overhead lines, significantly exceeding the zero-sequence voltage levels that occur in the line when the wire is broken. The device (L-1) has the ability to rebuild from short-term electromagnetic influence due to short circuits in the traction network, but the constant electromagnetic effect of the power lines leads to a zero-sequence voltage that exceeds the setting both in magnitude and in duration, which leads to failures in device operation.

To eliminate the above-mentioned disadvantages, it is possible to measure the zero sequence voltage at the end of the protected line and turn off the zero sequence voltage filter for a known predetermined time. Then, a comparison is made of the time during which there was a sharp increase in the voltage value measured on the filter at the beginning of the line. If the time coincides with the setting, the dangerous mode is disabled.

The technical result of the utility model is to increase the reliability of the device for determining the breakage of insulated wires of overhead lines with a voltage of more than 1000 V when they are located on the supports of the contact AC network in the zones of electromagnetic influence of high voltage power lines.

To the known device for determining the breakage of insulated overhead wire wires with voltages above 1000 V, consisting of a supply transformer, overhead wire wires installed at the beginning and end of two transformers, the secondary winding of which is included in the triangle, and the primary in the star, the zero point of which through the active a capacitive filter is connected to an artificial ground electrode; a threshold voltage element is connected in parallel with the capacitive filter included at the end of the line, the input terminals of which are connected to nye clamps threshold time member whose output terminals are combined with the input terminals of the second threshold time element. The output terminals of the threshold time elements are included in the control circuit of the switching device of the measuring transformer. At the beginning of the line, a threshold voltage element is connected in parallel with the zero-sequence voltage filter, the output terminals of which are connected to the input terminals of the logic unit, the output terminals of which are included in the control circuit of the switching device that disconnects the supply transformer.

The claimed utility model is illustrated in figure 1.

Figure 1 marked:

1 - power transformer;

2 - switching apparatus VL (high voltage switch, vacuum switch, etc.);

3 - overhead wires of a high voltage line;

4 - primary high-voltage winding of a transformer of the type TM or TS installed at the beginning of the protected line;

5 - secondary low-voltage winding of a transformer installed at the beginning of the protected line;

6 - active-capacitive filter installed at the beginning of the protected line;

7 - active-capacitive filter installed at the end of the protected line;

8 - primary high-voltage winding of a transformer of type TM or TS, installed at the end of the protected line;

9 - secondary low-voltage winding of the transformer,

installed at the end of the protected line;

10 - artificial ground electrode at the beginning of the line;

11 - artificial ground electrode at the end of the line;

12 - threshold voltage element on the filter at the end of the line with a given setpoint voltage zero sequence;

13 is a threshold time element with a given set point in time for the presence of voltage of the zero sequence of a certain value on the filter at the end of the line;

14 - switching apparatus of the measuring transformer at the end of the line;

15 is a threshold time element with a given setting for the time off the zero-voltage voltage filter at the end of the line;

16 - a threshold voltage element on the filter at the beginning of the line with a given setpoint voltage zero sequence;

17 - logical block

The proposed device for determining the breakage of insulated wires of overhead lines with a voltage of more than 1000 V when they are located on the supports of the contact AC network in the areas of convergence with high-voltage power lines works as follows.

If the insulated air wire (3) of the overhead line located in the zone of electromagnetic influence breaks off due to the operating voltage of the supply transformer (1) and the installation of two active-capacitive filters (6, 7) at the beginning and end of the line included in the ground zero circuit of the primary windings (4, 8) of the transformer, the secondary winding (5, 9) of which is connected in a triangle, through an artificial ground electrode (10, 11) and filter (6, 7), the zero-sequence current flows.

It was found that when the overhead line wire is broken with a voltage of more than 1000 V, the zero-sequence voltage drop on the filter (7) is significantly higher than the zero-sequence voltage, due to the total electromagnetic influence of the contact network voltage and current in the traction network and power lines.

When a break occurs, the threshold element (12), fixing the voltage level of the zero sequence, is triggered and sends a signal to the threshold time element (13). After a predetermined time value exceeding the time for switching off the short circuit mode in the traction network, the threshold time element closes the output contact and sends a signal to turn off the switching device of the measuring transformer (14). It was found that the time setting of the threshold element should not be less than 1 s. Simultaneously with the shutdown command, the threshold element starts the second threshold time element (15), which after a certain time has passed, gives a signal to turn on the zero-sequence voltage filter.

Thus, the threshold voltage element (16), which measures the voltage across the filter at the beginning of the protected line, is triggered and gives a signal to the logic block (17) for a time equal to the length of the sharp increase in voltage caused by the filter being turned off at the end of the line. If the set point and the length of time coincide, during which the threshold element (16) sends a signal to the logic unit, a signal is sent to turn off the overhead line by the switching device (2).

In the event that the zero sequence voltage exceeds the threshold element setting due to the magnetic influence of currents in the traction network or power lines during short circuits, only the voltage threshold element is triggered (12). The threshold time element (13) is triggered by the signal of the threshold voltage element, but does not have time to give a signal at its output due to the short duration of these modes (their duration is less than the specified time setting). The signal to turn off the overhead line will not come.

The proposed device for determining the breakage of insulated wires of overhead lines with voltages of more than 1000 V when they are located on the supports of the contact AC network in the areas of convergence with high-voltage power lines allows you to detach from the electromagnetic influence of both the traction power supply system and power lines, to ensure reliable disconnection of overhead lines whose wires are insulated .

The device also works reliably when the non-insulated OHL wires break when they fall to the ground, when the wire-to-ground transition resistance is significantly higher than the active-capacitive phase resistance relative to the ground, which occurs in areas with rocky and permafrost soils.

Sources of information taken into account when compiling the description.

1. A device for determining the breakage of insulated wires of overhead lines with voltages above 1000 V when they are located on the supports of a contact AC network. Authors: Kosarev A.B., Kuznetsov D.G., Loginov S.V. Utility Model Patent No. 2009108971/22, March 30, 2009 - 2 pp. (Prototype)

2. Kosarev A.B., Kosarev B.I. Fundamentals of electromagnetic safety of railway power supply systems. - M .: Intext, 2008.480 s.

3. Serov V.I., Shutsky V.I., Yagudaev B.M. Methods and means of combating earth faults in high-voltage systems of mining enterprises. - M .: Nauka, 1985 .-- 136 p.

Claims (1)

A device for determining the breakage of insulated wires of overhead lines with voltages exceeding 1000 V when they are located on the supports of a contact AC network in the areas of proximity to high-voltage power lines (power lines), consisting of a three-phase supply transformer, the secondary high-voltage winding of which is connected through the switching device to air-insulated wires of a high-voltage lines, at the beginning and end of which transformers are connected, the secondary windings of which are connected in a triangle, and the primary windings connected to a star, the zero points of which are connected to artificial earthing switches through active-capacitive filters, characterized in that in it, in addition to the zero-sequence voltage filter, a threshold voltage element is connected at the end of the line, the output terminals of which are connected to the input terminals of the threshold time element generating the signal to turn off the switching device of the measuring transformer and the trigger element of the filter on-time; at the same time, at the beginning of the line, a threshold voltage element is also connected in parallel with the voltage filter of the zero sequence, which supplies a signal to the logic unit, the closure of the output contacts of which leads to the disconnection of the switching apparatus of the high-voltage power line with insulated neutral.