SU890277A1 - Device for determination short circuit location in electric power line - Google Patents

Description

one

The invention relates to electrical measuring equipment and can be used to create devices for remotely determining the location of a short circuit in power lines.

A known method for determining the location of a short circuit in power lines, implemented in a device comprising a voltage ratio meter, a current meter and a trigger body 11.

A disadvantage of the known device is the low accuracy of determining the location of a short circuit.

The closest to the proposed technical entity is a device containing a voltage driver with three phase voltage inputs and three current inputs, the first three outputs of which are connected to the corresponding first three inputs of the switch, the control input of which is connected to the output

the damaged phase selection unit, the input of which is connected to the output of the starting organ, and the switch outputs are connected to the corresponding inputs of the voltage ratio measurement unit 2.

A disadvantage of this device is the large error in determining the location of the damage in case of two-phase closures through a transient resistance.

to

The aim of the invention is to improve the accuracy of determining the location of a two-phase closure.

Claims (2)

This goal is achieved by the fact that a device for determining a short circuit on power lines, containing a voltage driver with three inputs of phase voltages and with three current inputs, the first three outputs of which are connected to the corresponding first three inputs of the switch, the control input which is connected to the output of the damaged phase selection unit, the input of which is connected to the output of the triggering organ, and the switch outputs are connected to the corresponding inputs of the voltage ratio measurement unit, is removed by a filter, negative sequence currents and an additional switch, while the filter inputs of the negative sequence currents are connected to the corresponding current inputs of the voltage shaper, its three outputs are connected to the corresponding | Three inputs of the additional switch, the other three inputs of which are connected respectively to the three other outputs of the shaper voltage, and its three outputs. are connected, respectively, with the three other switchboard inputs) a. The drawing shows a block diagram of the device. The device contains a voltage driver 1 with three phase voltage inputs and three current inputs, a starting element 2, a damaged phase 3 selector unit, switch k, voltage ratio measuring unit 5, reverse sequence current filter 6, and additional switch. The device operates as follows. The voltage driver 1 instantaneously generates the value of the short circuit loop voltage (U), the voltage value on the line model (W), and the voltage (V) when the short circuit current passes through a zero value, for example, for six possible short loops at a three-phase voltage. The U, W and V values of the shaper thus formed are fed to the inputs of the additional switch 7. At the same time, a single-phase short circuit takes 16 as the value of V. And three values at the inter-phase: U - ie, U - ic; . -. t. - i. where L, Ij, TC currents, respectively, in phases A, B and C. When the closures are asymmetric x, three values of V are fed to the other inputs of the additional switch 7: ijA - ь (jze - jtc; ЬЬЬА, where l-iA, lab, tjc. - respectively, the negative sequence currents emitted by the filter of the negative sequence currents.In the absence of voltage V, the output of the additional switch 7 passes the voltage V. If there is voltage V, they pass to the output g. three-phase closures x fall phase current differences, and when two-phase - reverse sequence current differences. The trigger unit 2 and the damaged phase selection unit (or phases) 3 control the operation of switch A, ensuring the appearance at its outputs of the voltages U, W, and V corresponding to this short circuit loop. There is no measurement of the value of U / W at the moment when, whereby the result of the division is proportional to the distance to the closure point Formula of the invention A device for determining the short circuit location on power transmission lines containing a driver with three phase voltage inputs and three current inputs, the first three outputs of which are connected to the corresponding first three inputs of the switch, the control input of which is connected to the output of the damaged phase unit, the input of which is connected to the output of the trigger, and the outputs of the switch are connected to the corresponding inputs of the voltage ratio measurement unit, characterized in that, in order to improve the accuracy of determining the location of a two-phase short circuit, it is equipped with a negative sequence current filter an additional switch, with the filter inputs of the current of the Nena circuit connected to the corresponding current inputs of the driver, the voltages, its three outputs are connected to the corresponding three inputs of the additional switch, the other three inputs of which are connected respectively to the three other outputs of the voltage driver, and its three outputs connected respectively to the three other inputs of the switch. Sources of information taken into account in the examination 5 1. USSR author's certificate No. 321027, cl. G 01 R 31/08, 1968. 2. Relay protection and emergency control automatics. M ,, Energie, 4 "oh 1976, p. 23.