RU87806U1 - DEVICE FOR CONNECTION TO MEASURING TAPES OF HIGH VOLTAGE INPUTS - Google Patents

Abstract

A device for connecting to the measuring bends of high-voltage bushings, comprising a sealed housing, a contact element connected to a low-voltage bushing of the bush, and plates with electronic components, characterized in that for solving the task, the capacity of the lower arm is drawn from separate capacitors that electrically connect two plates with a conductive coating located around the perimeter around the terminating resistor and forming a three-dimensional shielding structure, one of the plates of which has in the middle part ielektricheskuyu region without conductive coating with a hole for passage of the resistor.

Description

The utility model relates to the field of measurement technology, namely to continuous monitoring of the state of high voltage electrical equipment using measuring taps of high voltage bushings and is intended for measuring random high-frequency overvoltages, the so-called “Very Fast Transient Overvoltages”, arising during the operation of disconnectors and switches in substations with Switchgear (Gas-insulated switchgear) voltage 330-750 kV. The device provides the ability to measure signals with an amplitude of tens to about a thousand volts in a wide frequency range.

Known devices: (RF Patent No. 2262761, 2005), in which resistors are used as the connection device (shunt) connected to the low-voltage output of the input plate. The disadvantage of this device is the inability to use it in high-frequency measurements, due to the limitation of transmitted in the frequency range.

Closest to the claimed utility model is a DB-type attachment device adopted as a prototype (Electro magazine No. 6, M. 2008, pp. 35-37 ") This device is a sensor in a sealed enclosure with a board with electronic components, which is intended for installation on bushings with capacitor isolation. The disadvantage of this device is that at high frequencies of overvoltage on the output connector of the device there is no way to get an undistorted signal in the entire frequency range due to the large inductance of the connection circuit.

The purpose of the utility model as a technical solution is to expand the frequency range of the measured signals to provide the possibility of registration arising during switching equipment surge.

A device for connecting to the measuring taps of the high-voltage bushings contains: a sealed housing, a contact element connected to the low-voltage tap of the high-voltage bushings and plates with electronic components. The principle of operation of the utility model is based on the preservation in a wide range of frequencies of the division coefficient of the capacitive divider, the upper arm of which is the main capacitance.

To fulfill this condition, the design of the lower arm of the divider must meet the following requirements:

1. The independence of the capacitance from the applied voltage.

2. Minimum inductance of the connection device.

To achieve the goal in the device, the lower arm of the divider is made in the form of a three-dimensional structure in which the required capacitance is selected from separate load capacitors placed between the electrodes in the form of plates having screens around the perimeter, so that the current-carrying conductor with a terminating resistor, whose resistance is equal to cable impedance is surrounded by shielding load capacitors. One plate is made of a solid conductor, and the second has a dielectric base coated with a conductive layer, in the center of which there is a dielectric region with an opening through which a terminating resistor passes. In the proposed device, the possibility of expanding the frequency range is achieved by creating a three-dimensional structure of individual capacitors in the low voltage arm of the divider. The inductance in the measuring circuit is reduced, resulting in the possibility of transmitting signals with a higher frequency. As a result, minimization of the inductance of the connection device circuit and shielding of the terminating resistor along which the signal is transmitted.

Figure 1 shows a diagram of a device for connecting to low-voltage measuring leads of high-voltage bushings, which has a sealed shielding housing 1, pin 2 and output coaxial cable 3. The electrical part of the device is made in the form of two plates 4, 5, one of which has a dielectric region of 6 s a hole for the passage of the terminating resistor 7 and the conductive region 8 connected to the housing. The plates are interconnected by concentrically arranged capacitors 9.

This device is planned to be used for monitoring high-frequency overvoltages at substations 330-750 kV with gas-insulated switchgears.

Claims (1)

A device for connecting to the measuring bends of high-voltage bushings, comprising a sealed housing, a contact element connected to a low-voltage bushing of the bush, and plates with electronic components, characterized in that for solving the task the capacitance of the lower arm is drawn from separate capacitors that electrically connect the two plates with a conductive coating located around the perimeter around the terminating resistor and forming a three-dimensional shielding structure, one of the plates of which has in the middle part ielektricheskuyu region without conductive coating with a hole for passage of the resistor.