RU2704606C1 - System of continuous monitoring of temperature of contacts of oil circuit breakers - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering, in particular to systems for monitoring parameters of oil circuit breakers of medium voltage. System for continuous monitoring of temperature of working contacts of oil three-pole switches, containing information and technical network, pyrometric sensors arranged on busbars of operating contacts of switches and connected by means of a signal input-output module to a controller for signal processing, a database server and a visualization panel arranged in a data acquisition cabinet configured to collect, process and transmit temperature data from the pyrometric sensors to the information and technical network, according to the disclosed invention is additionally equipped with a surge protection device in form of a data transmission interface protection module and placed on lines between pyrometric sensors and a signal input / output module, wherein communication lines are made in the form of shielded cable for protection against electromagnetic fields, and current-conducting buses of working contacts of oil switches are coated with high-temperature heat-reflecting device.

EFFECT: technical result consists in improvement of temperature control of working contacts of medium voltage oil circuit breakers.

4 cl, 5 dwg

Description

Technical field

The invention relates to a system for monitoring the parameters of an oil circuit breaker of medium voltage with an open arrangement of working contacts, in particular, monitoring the temperature of working contacts of switches MGU-20 or similar.

State of the art

The operating contacts of the oil switches of the MGU-20 brand or similar are copper knives connected by lamellas with copper current-carrying tires and are located in the open air. Because of this, they are exposed to dust from the air, which leads to a deterioration of the conductive properties of the contacts, resulting in excessive heating of the contact group, conductive elements and switch tanks, which usually leads to emergency consequences in case of untimely detection by operational personnel and failure to take measures for unloading the circuit breaker.

In the power supply system of aluminum smelters and other industrial enterprises, medium voltage circuit breakers are an important element for ensuring reliable and stable power supply to electricity consumers. In conditions of high current and voltage, the reliability of power supply is associated with heating of the contacts of the switching equipment. When electrical equipment is operating, high dust content, frequent switching and a long service life can increase contact resistance, cause an increase in the contact temperature of the circuit breaker and oxidation of the contact surface. This causes an avalanche-like increase in the contact resistance of the switch contact and, ultimately, leads to equipment damage due to fires and interruptions in power supply.

There is currently no effective way to continuously monitor the temperature of the circuit breaker contacts. One of the reasons is that the switch contacts are under high voltage, and the contact method for measuring temperature (for example, using a thermocouple) cannot be used. Secondly, the existing method for measuring temperature using periodic thermal monitoring by personnel has its drawbacks: only working contacts from the front of the circuit breaker are available for monitoring, and this control does not allow to evaluate the state of the circuit breaker contacts. Thirdly, when switching, electromagnetic interference occurs in the switch cell, which adversely affects the operation of the equipment. Fourth, the measurement object (operating contacts of the switch) is made of copper and has a very low absorption coefficient, which makes it difficult to measure temperature with a pyrometer or thermal imager. Fifthly, when the circuit breaker is overhauled, it is almost completely disassembled and, accordingly, the temperature control system should have the ease of mounting and dismounting of measuring sensors.

A known monitoring system of non-contact temperature monitoring of the infrared range for the contact of the high voltage switch (patent CN 20142683056, publ. 2015-07-22), consisting of an infrared temperature sensor, microprocessor unit, keyboard, display, sound and light alarm unit, level conversion unit, CAN bus controller, optocoupler isolation unit.

The infrared sensor of the temperature matrix performs non-contact temperature measurement of the high-voltage switch contact in the high-voltage cabinet, and the measured signal is sent to the microprocessor unit, the result is analyzed, and the temperature is displayed on the display screen in real time; on the other hand, the level conversion unit performs level conversion, and the converted level is input into the CAN bus controller and the CAN transceiver controller via the optocoupler isolation unit, and its output is sent to the CAN bus, which allows you to connect and process this data in real time at a remote location workstation or computer equipment of the control center on the CAN bus. When the contact temperature of the high voltage switch exceeds the set temperature, the sound and light signaling device emits sound and light. The keyboard unit and the microprocessor carry out a human-machine dialogue, and the parameters to be detected are set in accordance with specific conditions.

According to the purpose, according to the technical nature and the presence of similar features, this solution is selected as a prototype.

A disadvantage of the known system is that when using unshielded communication lines of infrared sensors with a microprocessor unit, as well as in the absence of surge protection devices, interference from electromagnetic influences of power equipment can occur, affecting the measurement result, in addition, it is impossible to use copper contacts of high-voltage switches to achieve the required measurement accuracy due to the influence of reflected heat. Also, the use of infrared sensors of a fixed design reduces the convenience of servicing circuit breakers during overhaul.

Disclosure of invention

The objective of the invention is to increase the reliability of power supply of electrolysis buildings, as well as other consumers of electricity, the exception of an emergency.

The technical result is to solve the problem, namely increasing the temperature control of the working contacts of medium voltage oil circuit breakers.

The technical result is achieved by the fact that the system of continuous monitoring of the temperature of the working contacts of oil three-pole switches, containing an information technology network, pyrometric sensors located on the current-carrying busbars of the working contacts of the switches and connected via a signal input-output module with a controller for signal processing, a database server and visualization panel located in the data collection cabinet, configured to collect, process and transmit temperature data with pyrometric x sensors in the information technology network, according to the claimed invention, is additionally equipped with a surge protection device made in the form of a protection module for data transmission interfaces, and placed on the lines between the pyrometric sensors and the signal input-output module, while the communication lines are made in the form shielded cable for protection against electromagnetic fields, and current-carrying busbars of working contacts of oil circuit breakers are coated with high-temperature heat-reflecting means.

The proposed automated system for monitoring the temperature of the working contacts of oil switches contains pyrometric sensors connected to the controller for signal processing, a server and a visualization panel located in the data collection cabinet. The data collection cabinet provides for the collection, processing and transmission to the upper level of information from pyrometric sensors installed at each pole of a three-pole switch and fixing the heating temperature of the working contacts. The number of pyrometric sensors is determined by the number of breaks in the circuit breaker, i.e. for each gap (a separate place of temperature control) requires its own sensor. For example, for a three-pole circuit breaker with two parallel circuits and two breaks per pole, 12 sensors are needed.

Preferably, the system contains devices for protection against impulse noise on the communication lines of the pyrometers and the data acquisition cabinet, and also these lines are made of shielded cable to protect against electromagnetic fields of electrical equipment.

The system may include a bracket for mounting pyrometers on the switch for ease of installation and dismantling during overhaul of the switch.

Also, the controlled surfaces of the working contacts of the oil circuit breakers can be painted with a high-temperature matte film-forming substance, for example, matte paint, to increase the accuracy of temperature measurement due to protection from reflected heat.

The invention is illustrated by drawings:

In FIG. 1 presents a structural diagram of the inventive system; in FIG. 2 shows the arrangement of pyrometric sensors on the switch; in FIG. 3 shows the mounting of sensors on a bar, as well as a bar to the upper channel of the switch; in FIG. 4 shows a general view of the switch indicating the location of the sensors; in FIG. 5 shows the main current-carrying circuit of the circuit breaker with current-carrying tires and sipes.

The system contains the following structural elements:

1 - Pyrometric sensors;

2 - switch;

3 - surge protection device;

4 - Controller;

5 - Signal input-output module;

6 - database server;

7 - Network switch;

8 - visualization panel controller;

9 - visualization panel;

10 - Uninterruptible power supply;

11 - Data collection cabinet;

12 - Twisted pair;

13 - Information Technology Network (ITS) of the Ethernet plant;

14 - Automated Workplace (AWP) of operational dispatching personnel;

15 - Working contacts of the switch;

16 - Metal strip;

17 - Upper channel of the switch;

18 - Bracket;

19 - Current-carrying bus circuit breaker;

20 - Lamels.

As a solution, an automated system for continuous monitoring of the temperature of the working contacts of oil switches of the MGU-20 type is proposed.

The temperature of the working contacts of the oil switches is controlled by a non-contact method using infrared pyrometric sensors 1. The sensors are installed above each of the 12 working contacts 15 of the switch 2 with brackets 18 on a metal, preferably aluminum, strip 16 mounted on the upper channels 17 of the switch 2.

The signals from the sensors 1 are transmitted via twisted pair 12, shielded and grounded to protect against electromagnetic interference, to the controller 4 by means of signal input-output modules 5 through devices for surge protection 3, made in the form of protection modules for data transmission interfaces, which consist of cascades on three-electrode two-chamber arresters and cascades on protective diodes (suppressors). The controller 4 receives, buffers and transmits data to the database server 6. The signals are switched through the network switch 7. All of the above equipment is located in the data collection cabinet 11, which is installed in the electrical installation with controlled switches. The equipment of the data acquisition cabinet is electrically powered from an uninterruptible power supply 10 to ensure continuity of contact temperature control.

Database server 6 processes, selects, and stores data. The temperature of the working contacts 15 of the oil switches 2 put into operation is recorded in the database with a frequency of 1 min. Data on database server 6 is archived with a depth of 6 months.

On the door of the data collection cabinet 11 there is a visualization panel 9 for displaying the current temperature of the working contacts, the state of the system based on the controller 4 of the visualization panel 9.

Data from the database server 6 goes to the existing Automated Workstations (AWSs) of the operational-dispatching personnel 14.

The software of the automated system of continuous temperature control, installed on the workstation, is autonomous, without interaction with existing software (software). Using the software of an automated temperature monitoring system, remote monitoring of the entire system is performed: visualization of temperatures on the screen, alarm and warning alarms, system settings, viewing the history of events, accumulated data, and generating reports.

The controller 4, the database server 6 and the AWP 14 communicate via the factory information network Ethernet 13.

Claims (4)

1. A system for continuous monitoring of the temperature of the working contacts of oil three-pole switches, containing an information technology network, pyrometric sensors located on the current-carrying buses of the working contacts of the switches and connected via a signal input-output module with a controller for signal processing, a database server and a visualization panel, in a data collection cabinet, configured to collect, process and transmit temperature data from pyrometric sensors to the information technology set b, characterized in that it is additionally equipped with a surge protection device made in the form of a data interface protection module and placed on communication lines between the pyrometric sensors and the signal input-output module, while the communication lines are made in the form of a shielded cable to protect against electromagnetic fields, and current-carrying tires of working contacts of oil switches are covered with high-temperature heat-reflecting means. 2. The system according to claim 1, characterized in that the sensors placed on the current-carrying tires of the working contacts are fixed to them by means of brackets connected to a metal strip located on the upper channel of the switch by means of a screw connection. 3. The system according to p. 1, characterized in that as a heat-reflecting coating using a matte film-forming material. 4. The system according to claim 1, characterized in that it is configured to process and store data for a period of at least 6 months.

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