SU562702A1 - Device for light guiding overhead power line supports - Google Patents

Description

(54) DEVICE FOR LIGHTING THE SUPPORT OF THE AIR LINES FOR POWER TRANSMISSION

The purpose of the invention is to increase the voltage stability of the lighting lamps and the reliability of their power.

This is achieved by the fact that in the proposed device for the light-guiding of the supports of the electric power transmission line with an isolated lightning protection cable connected to the supports through the windings of two-winding transformers, the other windings of which are connected to the lighting lamps and to the corresponding power sources of these lamps, the lightning protection cable is connected to the pole from the supports through corresponding capacitor.

FIG. 1 is a schematic electrical diagram of a device for light arresters on a stand of an overhead transmission line; in fig. 2 and 3, respectively, the replacement scheme of the proposed device and its design scheme.

The lightning cable / (see Fig. 1) at the transition site is insulated from the supports 2 by insulators 3. On the supply side, a local source 4 of electricity, for example, a downstream transformer, is connected to one winding of the transformer 5 and to the lamps 6. Secondary winding of the transformer 5 s Both sides of the junction are connected at one end to a ground wire / and the other to a grounded support 2. Capacitors 7 are connected in parallel with this winding. Lamps on the opposite support from the power supply are connected to the second winding of the transformer 5. Condenser protection the valve and overvoltage lamps are provided by valve dischargers 8. A choke can be used to reduce the steepness of the wavefront of an overvoltage, and a spark gap to reduce the amplitude of the wave. The capacitance of the capacitors is chosen so that the voltage on the cable relative to the ground when the source of electricity is disconnected is much less than the voltage of this source connected to the cable through an isolating transformer. The capacitor attenuates the electrically induced field near the cable due to the electromagnetic field caused by the current flowing through the capacitor under the effect of the induced voltage.

The transformer (in most cases, step-up) is designed to reduce the voltage losses in the power transmission system (cable - ground), as well as to coordinate the insulation, i.e., to exclude the possibility of its damage due to ground faults in the network. To ensure this condition, the voltage on the winding of the transformer connected to the ground wire must be greater than the voltage induced on the cable when it is connected to ground.

The circuit of the proposed device (see Figs. 2 and 3) contains two sources of electrical energy with voltages U- and U ,.

The voltage f / e is the voltage of the equivalent generator to which the antenna power take-up circuit is converted, and the equivalent capacitance C e is the internal resistance of this generator. The voltage f / is the local source voltage, applied to the transformer winding connected to the ground wire.

The resistance Zs in the calculation scheme (see Fig. 3) is the sum of the internal resistance of the local source and the resistance of the loop of the cable - the earth at the transition point; ZH is the load resistance.

The capacitance of the bypass capacitor is selected according to the condition:, while the voltage V has practically no effect on the load voltage. It is convenient to use cosine capacitors with a voltage of 3-10 kV as the capacitor capacitor. Advantages of the circuit with capacitors:

load load does not depend on the operating modes of the power line and does not depend much on the change in power of the load;

the convincing voltage of the transformer connected to the cable can be chosen to a certain extent arbitrarily, which facilitates the choice of a standard transformer;

the capacitor does not consume active power; its use only improves the local f of the local source;

turning off the local source does not lead to an increase in the cable potential and triggering of the arresters;

a capacitor reduces the slope of the wave front of atmospheric overvoltages and facilitates protection against these overvoltages;

in comparison with the ground cable, its protective properties are improved, since the potential of the cable relative to the ground is reduced; by reducing the potential of the cable, the distance between the electrodes of the protective gap is reduced, which also improves the protection of equipment against overvoltages.

FIG. 1 shows a device with a single ground wire cable.

Usually, at large junctions, two cables are used for voltage kV and above. In this case, the circuit is fundamentally preserved (it is possible to use both cables for power transmission with the implementation of the reservation).

The technique of the economic efficiency of the invention is determined by the ability of the power supply from a single source of electricity to luminaires of two or more supports with a large junction length, regardless of the voltage and level of ground-fault currents. In this case, there is no need to lay a power line to each support, the extent of which can be significant.

Claims (3)

1.Bulashevich DN, Yurenkov V.D. Capacitive power take-off from power lines, SEI, 1959, p. 82 2. Author's certificate LL 356425, cl. F21 S 3/10, 1971. 3. Type work № 51-E VGPI "Teploelektroproekt. Capacitive power takeoff from power lines 110-220 kV, M., 1952 (prototype). -, - Sy Z /.