SU1394302A1 - Device for controlling heating system modes of a factory-assembled switchgear - Google Patents

Abstract

The device relates to electrical engineering, in particular to complete switchgear, and can be used to control the mode of operation of their heating system. The purpose of the invention is to increase reliability and reduce power consumption for own needs. This goal is achieved by the fact that the unit containing the unit for measuring the temperature 1 and the unit 3 for relative humidity of the air, the starting organ of the central signaling of the earth fault, additionally introduced the unit 5 for measuring the temperature of the surface of the insulator, the unit 2 for determining the dew point. The measured values of air temperature and relative humidity (blocks 1 and 3) are fed to the inputs of block 2, at which the dew point is determined. At the output of adder 4, a signal is proportional to the difference in temperature of the insulator surface and dew point, which is fed to the inputs of differentiating amplifier 6, comparators 7 and 8, adder 9. If the predicted parameter reaches a negative value, the comparator 10, the element OR 13 and the executive body 14 to turn on the heating system. 1 hp f-ly, 1 ill. (L

Description

The invention relates to the field of electrical engineering, in particular to complete switchgear (CIR), and can be used to control the mode of operation of their heating system.

The purpose of the invention is to increase the reliability of the complete switchgear and reduce power consumption for its own facilities.

The drawing shows the functional diagram of the device.

Line 22, the output of which is connected to the output of block 2.

The device works as follows.

In blocks 1 and 3, measurement and generation of signals proportional to the temperature and relative humidity of air in the switchgear are carried out, which are fed to the inputs of the dew point unit 2.

The condition for dew on the surface of the insulators is that the dew point of the temperature surface is exceeded.

The device contains a block 1 measuring-15 isolator. The greater the difference between

nor the air temperature in the switchgear assembly, the output of which is connected to the first input of the dew point determination unit 2, the second input of which is connected to the output

Line 22, the output of which is connected to the output of block 2.

The device works as follows.

In blocks 1 and 3, measurement and generation of signals proportional to the temperature and relative humidity of air in the switchgear are carried out, which are fed to the inputs of the dew point unit 2.

The condition for dew on the surface of the insulators is that the dew point of the temperature surface is exceeded.

air temperatures and the surface of the insulator, the dew drops out at lower values of humidity. This dependence is determined from the boundary condition

The relative humidity measurement unit 3, the output of the dew point determination unit, is connected to the first input of the first adder 4, the second input of which is connected to the output of the insulator surface temperature measurement unit 5. The output of the adder 4 is connected to the inputs of the differentiating amplifier 6, the first 7 and second 8 comparators, as well as to the first input of the adder 9, the second input of which is connected to the output of the differentiating amplifier 6, and the transducer is connected to the input of the third comparator 10. The output of the comparator 8 is connected to the first input element And And, the second input of which is connected to the output of the starting body 12 of the centralized signaling about the circuit to earth. The outputs of the element And And, the comparators 7 and 10 are connected to the inputs of the element OR, 13, the output of which is connected to the executive body 14.

The dew point determination unit 2 contains the first amplifier 15 and the third adder 16 connected to the first input of block 2. The output of the third adder 16 is connected to the first input of an analog multiplier 17, the second input of which is connected to the output of a logarithmic amplifier 18s whose input is connected to the second input block 2. The output of the analog multiplier 17 podklyu.en to the first inputs of the fourth 19 and fifth of the 20 adders. The second input of the adder 20 is connected to the output of the amplifier 15. The outputs of the adders 19 and 20 are connected to the corresponding inputs of the analog divider 21, the output of which is connected to the input of the second amplifier

 E

Ty

(one)

where is e

Ty

f

re

 falling dew

saturated steam elasticity

at surface temperature

isolator;

saturation elasticity at

dew point.

The saturation elasticity at temperature is defined as.

EU THAT

 dew

(2)

where is E.

Those

ETV - about b + TB

 falling dew

- elasticity of saturated steam at air temperature Tg; tf is relative humidity. The saturation elasticity at Tg is determined by the Nagnuss formula

aTV

(3)

 falling dew

where Eg is the elasticity of the temperature at temperature, OS; a, b. are constant coefficients.

Represents the surface temperature of the insulator as

T T „- yT,

(four)

where DT is the difference between temperatures

air and insulator, substitute the expressions (2, 3, and 4). in formula (1), find from it

DT

 .12

(L + TD / Inif - a-b

(five)

The dew point is determined by the formula

btlntf (b + tv1 ,, h

  (l + f;)

derived from expressions (2) and (3).

Block 2 allows, by successive operations, to obtain at the output a signal proportional to a point, dew.

The elements of block 2 allow to receive the following signals at their outputs: amplifier 15 - adder 16 - (L + Tft); log amplifier 18 - Inif; analog multiplier 17 - + Ta); adder 19 - a-b - IntfCb + T,) 3; adder 20 - a.Tg + ln (f (b + Tg); analog divider 21 - the result of dividing HaJna sig from output 20 into signal from output 19; amplifier 22 - the signal is proportional to the dew point.

In adder 4, a signal is formed that is proportional to the temperature difference between the surface of the insulator and the dew point ;, which is fed to the inputs of differentiating amplifier 6, comparators 7 and 8, adder 9. Differential amplifier 6 generates a signal proportional to the rate of change of temperature difference between the isolator ra and dew point multiplied by the average operating time of the heating system.

those.

V.-to

The value of t is determined by the design features of the switchgear cabinet, inertia of the heating system, the power of the heating elements and is at least 25 minutes. In the adder 9, a signal is generated that is proportional to the expression.

dt ". RT; V- t

R

(7)

35,

1. A device for controlling the operation mode of the heating system of a complete switchgear device containing a unit for measuring temperature and relative air humidity, a triggering body for centralized earth fault signaling, an actuator that differs in that in order to reduce power consumption

for its own needs and for improving the reliability of the complete switchgear, it additionally contains a block to measure the temperature of temperatures through the insulator surface

determine the dew point, the first adder, the differentiating amplifier, the first, second and third comparators, the second adder, the element OR, the element AND,

where & T is the predicted difference

temperatures, i.e. the value of which reaches the size t (j at a constant rate of change of this difference, If the value is $ O, then the comparator 10, the OR element 13 g is triggered, the output of the tempi measuring unit, the actuator, 14 is turned on to turn on the heating system. The comparator triggers 10 means that through time tg dew will fall on the insulators.

Comparator 7 is triggered if the value of the temperature difference LT-Hs. The introduction of the comparator 7 increases the reliability of the device in cases where the rate of change of the temperature difference is insignificant, and due to the limited sensitivity of the measuring units for air parameters and the insulator, i.e. when approaching

50

55

The air inlet is connected to the first inlet of the dew point determination unit, the second inlet of which is connected to the outlet of the relative humidity measuring unit; the outlet of the dew point determining unit is connected to the first inlet of the first adder, the second inlet of which is connected to the outlet of the insulator surface temperature measuring unit; the first adder is connected to the inputs of a diArtifying amplifier, the first and second comparators, as well as to the first input of the second, adder, the second input of which

O value

and yTpo 0.

five

0 5

0

five ,

Comparator B is triggered if the value of the temperature difference LT; 3 ° C, in this case, if one of the phases of the network is shorted to earth, then the centralized signaling device for the earth fault trigger 12 is detected, the element 11 is activated and the element 13, the actuator 14 is then activated. neutral neutrals are accompanied by arc overvoltages exceeding the phase voltages by a factor of 3.5–4 and dT; . Therefore, the introduction to the scheme of elements 13 and 11 increases the reliability of the device.

Thus, the device allows forecasting the dew on the KRU isolators and, depending on this, controls the operating mode of the heating system with the greatest efficiency.

Claims (2)

1. A device for controlling the operation mode of the heating system of a complete switchgear device containing a unit for measuring temperature and relative air humidity, a triggering body for centralized earth fault signaling, an actuator that differs in that in order to reduce power consumption for own needs and for increasing the reliability of the complete switchgear, it additionally contains a block to measure the temperature of the insulator surface, 0 five The air inlet is connected to the first inlet of the dew point determination unit, the second inlet of which is connected to the outlet of the relative humidity measuring unit; the outlet of the dew point determining unit is connected to the first inlet of the first adder, the second inlet of which is connected to the outlet of the insulator surface temperature measuring unit; the first adder is connected to the inputs of a diArtifying amplifier, the first and second comparators, as well as to the first input of the second, adder, the second input of which connected to the output of a differentiating amplifier, the output of the second adder is connected to the input of the third comparator, the output of which is connected to the first input of the OR element, the BTOpoil input of which is connected to the output of the first comparator, the third input of the OR element is connected to the output of the AND element - the comparator, and the second input is connected to the output of the starting body of the centralized signaling of the earth fault, the output of the OR element is connected to the input of the executive body. 2. Device pop, 1, characterized in that the dew point determination unit contains the third, fourth and fifth adders, the first and second amplifiers, the logarithmic the amplifier, aa multiplier and a divider, with the inputs of the first amplifier and the third adder connected to the first input of the unit, the output of the third adder connected to the first input of the analog multiplier, the second input of which is connected to the output of the logarithmic amplifier whose input is connected to the second input of the unit analog multiplier is connected to the first inputs of the fourth and fifth adders, the second input of the fifth adder is connected to the output of the first amplifier, and its output is connected to the first input of the analog divider, the second input of which is connected to the output of the fourth adder, the output of the analog divider is connected to the input of the second amplifier, the output of which is connected to the output of the block.