SU1707676A1 - Electric heating control device for outdoor metal-clad switchgear - Google Patents

Abstract

The invention relates to electrical engineering and can be used in outdoor switchgear complete sets (KRUN). The purpose of the invention is to enhance the functionality and increase reliability. The device contains units for measuring the temperature and humidity of the air, a triggering organ of the earth fault alarm, an actuator, a dew point determination unit and a logic unit. In addition, a timer, a unit for determining the rate of temperature change, a comparator, and an I element are introduced into the device, which allows for monitoring the operation and operability of the heating elements in the switchgear. 1 il.

Description

The invention relates to electrical engineering, namely to outdoor switchgear complete sets (KRUN) 6-10 kV.

Isobenie is the enhancement of functionality and increased reliability.

The drawing shows a block diagram of the proposed device.

The device contains a temperature measurement unit 1, an air humidity measurement unit 2, a dew point determination unit 3, a logic unit 4. an insulator surface temperature measurement unit 5, an earth triggering authority 6, a centralized earth fault alarm, an actuator 7, a timer 8, a block 9 determining the rate of change of air temperature, the comparator 10, element 11, the logic unit 4 consists of the first adder 12, the differentiating amplifier 13. the first

14 and the second 15 comparators, the second adder 16. the third comparator 17. element 18 and the element OR 19.

The device works as follows.

The signals from temperature measuring units 1 and air humidity 2 are fed to the inputs of the dew point determination unit 3. From the output of which a signal proportional to the dew point temperature is fed to one of the inputs of logic unit 4, to the other two inputs of which signals are sent from measuring unit 5 the temperature of the surface of the insulator and starting body 6 centralized signaling of the earth fault. Depending on the ratio of the temperature of the surface of the insulator and the temperature of the dew point, as well as on the presence of a signal from a centralized signaling the earth fault logic unit 4 generates a signal to turn on the performer i i

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and

heater 7, and the signal is given in advance (not less than 25 minutes) before the predicted equalization of the temperature of the insulator surface and the dew point temperature, i.e. moment of dew on a controlled object. Simultaneously with the activation of the actuator 7, a timer is started. 8, which starts counting the time delay, which is less than the prediction time of the dew point (10-15 minutes). During normal operation of heating elements, their operability and sufficient power, the temperature in the internal volume of the metal-clad switchgear begins to increase and a signal proportional to this speed, more than zero, appears at the output of the unit 9 for determining the rate of change in air temperature. At the same time, the output of the comparator 10, connected to one of the inputs of the element 11, is set to a logical zero. The logical unit that is set at the output of timer 8 after the specified time has elapsed and goes to the second input of AND 11 will not change the logical zero at its output. This state corresponds to the normal operation of the heating elements.

With faulty heating elements or their insufficient power, the temperature in the internal volume of the switchgear will continue to decrease. In this case, the signal at the output of the block 9 for determining the rate of change of air temperature will be less or equal to zero. In this case, a logical one will be set at the output of the comparator 10. As soon as the output of the timer 8 through Wits logical unit is not the output of the element And 1 there is a signal that the heaters are faulty or do not provide effective heating due to insufficient power.

Thus, the invention allows not only to control the electrical heating of the internal volume of the KRUN, but also controls the efficiency of this heating and the operability of the heaters without installing additional sensors, i.e. functionality is enhanced and device reliability is improved.

Claims (1)

Apparatus of the Invention A device for controlling the heating of an outdoor outdoor switchgear unit comprising temperature and humidity measuring units, a starting organ of a centralized earth fault signaling unit measurements of the temperature of the insulator surface, the actuator, the dew point determination unit and the logic unit consisting of the first and second adders, the first, second and third comparators. differentiating amplifier, AND element and OR element, characterized in that, in order to expand its functionality and increase reliability, it is equipped with a timer, a unit for determining the rate of change of air temperature, a comparator, element I, and the output of the unit for measuring the air temperature is connected to the first input of the unit for determining the dew point; the second input of which is connected to the output of the unit for measuring relative air humidity, and the output of the dew point determination unit is connected to the first input of the first adder of the logic unit, the second input which is connected by the output of an insulator surface temperature measurement unit, the output of the first adder is connected to the inputs of a differentiating amplifier, the first and second comparators, as well as the first input of the second adder of the logic unit, the second input of which is connected to the output of the differentiating amplifier, the output of the second adder is connected to the input of the third comparator whose output is connected to the first input of the OR element, the second input of which is connected to the output of the first comparator, and the third input of the OR element is connected to the output of ementa and logic unit, whose first input connected to the output of the second comparator, and the second input is connected to the output of the starting organ of the centralized earth fault alarm, the output of the OR element is connected to the input of the executive body and to the timer input, and the timer output is connected to the first input of the element I, the output of which is included in the malfunction alarm circuit, and the second input is connected to the output of the comparator, the input of which is connected to the output of the air temperature change rate unit, and the last input is connected to the output air temperature measuring unit.