SU1499280A1 - Electric installation - Google Patents

Abstract

The invention relates to electrical engineering and can be used to assess the state of insulation of electrical installations containing direct current electrical networks. The purpose of the invention is to improve the reliability of electrical installations by increasing the reliability of monitoring the state of their parameters, such as insulation resistance and network capacity, by reducing the time of transients for recharging the capacities of the monitored network after switching in it. The electrical installation contains switches 1 and 2, low-resistance resistors 3 and 4, capacitors 5 and 6, control and measurement unit 7, clock generator 8, logic elements 9 and 10, load 11, electric power source 12 and, differentiating unit 13, threshold elements 14 and 15, connecting bus 16, feeder 18, switch 17 / feeder /, load 19 feeder. When the feeder 18 is connected to the network, a transient begins, as evidenced by the signal from the output of the differentiating unit 13 and the threshold element 14 or 15, which, through an AND 9 or 10 logic element using pulses from the generator 8 to the second input switch 1 or 2, which periodically connects to the network the capacitor 5 or 6, and in the intervals between pulses the capacitor 5 or 6 by the connector 1 or 2 to the low-resistance resistor 3 or 4 and is quickly discharged. This continues until the transition process ceases. 1 il.

Description

3

4-6

sixteen

-.22

P

IS

§

b2fi t

AND

(L

WITH

 Pg / (3

 15

U

four:

; about with

ND

CX

31499280. about

out pulses, AND 1 O logic elements using 9 and 10 supplied to its secondary, 11, source 12, 12 input of pulses from the generator of electrical energy 8, differentiating unit 13, threshold elements 14, and I 5, connecting buses 16, feeder 18 , switch 17 feeder, load 19 feeder. When the feeder 18 is connected to the network, the transition begins in the network.

  . .,. m .fwm f - «VLM LHL L - f tltfij L Wn -

the process, as evidenced by the signal to the resistor 3 or 4 and quickly output of the differentiator unit 13p. So it goes on to those

and threshold element 14 or 15, as long as the transitional priority is not controlled through the logical element AND 9 is terminated. 1 il.

clock pulses are controlled by switch I or 2, which periodically connects capacitor 5 or -6 to the network, and in the intervals between pulses, capacitor 5 or 6 is connected by switch 1 or 2 to low and 1 o using pulses to its second input from generator 8

 .,. m .fwm f - «VLM LHL L - f tltfij L Wn -

The 3 or 4 capacitor and the fast pulse opening control the switch I or 2, which periodically connects the capacitor 5 or -6 to the network, and between the pulses, the capacitor 5 or 6 is connected by switch 1 or 2 to the low

g-

The invention relates to electrical engineering, in particular, to the assessment of the state of insulation of electrical installations containing direct current electrical networks.

The purpose of the invention is to increase the reliability of operation of an electrical installation j containing direct current electrical networks, by increasing the reliability of monitoring, for example, insulation resistance and network capacity, by reducing the time of transient processes for recharging network capacities with changes in insulation resistance and electric network capacity, including and tele switching in it.

On what is shown is a functional diagram of the device.

The device contains switches 1 and 2, low-impedance resistors 3 and 4, capacitors 5 and 6, control and measurement unit 7, generator 8 clocks, logic elements 9 and 10, load 11, electric power source 12, differentiating unit 13, threshold elements 14 and 15, connecting tires 16, switch (feeder) 17, feeder 18, feeder load 19.

Source 12 is connected by connecting buses 16 with load 11 and through switch 17 to feeder 18 and load connected by it 19. Control and measurement unit 7 is connected by one input to one of the buses 16 of the monitored network and the other input to the ground bus. The first outputs switch € & 1 and 1 and 2 are connected respectively to the first and second buses 16. The second outputs of the key switch 1 and 2 are

25

thirty

20 35

40 45

55 50

The cut resistors 3, and 4 are respectively connected to the ground bus. The second (controllable) inputs of switches 1 and 2 are connected to the outputs of logic gates 9 and 10, respectively, the first inputs of which are connected to the output of the differentiating unit 13, whose input is connected to one of the buses, through the threshold elements 14 and 15, and the second inputs logic elements 9 and 10 are connected to the output of the generator 8 clock pulses.

The drawing also shows the resistances 20 and 21 of the insulation and the capacitance 22 and 23 of the poles relative to the ground and the resistance of the insulation 24, 25 and the capacitance 26 and 27 of the poles of the Leader 18 relative to the earth.

Electrical installation works as follows.

When the switch 17 is turned on (or turned off) in the supervising network, a transient reloading of the network capacities 22 and 23, 26 and 27 occurs. This is due to the fact that, firstly, the total insulation resistance value changes tire (pole) network in relation to. secondly, the magnitude of the tire capacitances (poles) relative to the earth changes.

The signal about the occurrence of a transitional recharge of capacitances of buses (poles) of the network from the output of differentiating unit 13 to the opposite threshold elements 14 and 15, at one of which, depending on the polarity of the signal at the output of unit 13, defined by increasing or decreasing the potential of the tire relative to the ground, a high level signal is formed - a logical unit. This signal from the output of the threshold element 15, for example, with increasing potential on the bus, goes to the first input of the logic element 10, the second input of which receives pulses from the output of the generator 8 clocks. These pulses through the logic element AND 10 are sent to the control input of switch 1, which in this case ensures the disconnection of the first input of switch 1 from the second code (initial state) and the connection of this first input to the first output (operating state in transient). Resistances 20 and 21 of the network recharge isolation do not reach the level (and speed) at which the signal about the presence of a transient process in the monitored network disappears from the output of differentiating unit 13 and threshold element 15. The signal from the first input of the logical element 10 will disappear high level Logic 10 unit, low level signal appears Logical zero. The pulses from the generator 8 will cease to pass through the AND 10 logic element, the switch 1 will return to the initial state when the capacitor 5 is closed

15

to low impedance 3.

When the potential on the splint to which block 13 is connected decreases, the network signaling (when connected) shunts a high level and appears at the output with a capacitor 5. This provides the threshold element 14 and through the creation of the low-impedance channel of the recharging network capacities, which means - it increases the speed (consequently, reduces the time) overcharging. However, in the process of recharging the capacitors 22 and 26, 23 and 27 of the network, the forcing of the recharge capacitor 5 is charged, as a result of which its impedance (resistance) to the current of the accelerated recharge increases. Therefore, the clock frequency of the 8 clock pulses and the duration of the pulses themselves are chosen so that during the presence of the pulse the charge capacitor 5 has a small charge, which ensures a small impedance (resistance) of the boost capacitor 5 for the accelerated overcharge current. During a pause between the pulses, the switch 1 returns to its initial state when the first input of the switch moves away from the first output and is connected to the automatic And 9 is fed to the controlled input of the switch 2. As a result, the capacitor 6 is connected in parallel to the insulation resistance 21, creating the time of the presence of a pulse from the generator of 8 clock pulses, the low impedance channel of the accelerated recharge of the network capacitances, and in the pause between the pulses is discharged through

thirty

35

40

low impedance resistor 4, i.e. The work proceeds according to the same algorithm, which is described for the case when the potential on the bus increases with respect to the ground.

Claims (2)

Invention Formula Electrical installation containing a DC power network consisting of a source of electrical energy, connecting buses, loads, feeder, control and measurement unit, the first input of which is connected rum out. Due to this, during pauses 45, the first connecting bus and, while pulsing, the capacitor 5 is closed to a low-resistance resistor 3, which ensures its accelerated discharge (return to zero initial conditions in the pause between pulses. When the next pulse arrives from the generator 8, the next cycle of acceleration of recharging and capacitances of the network with the capacitor 5 freed from the accumulated one begins at the previous charge pulse. These cycles of accelerated recharging continue until the degree This input is connected to the earth bus, which is different from the fact that, in order to improve the reliability of the electrical installation, it is additionally introduced with two two-position switches, two capacitors, two low-resistance resistors, a differentiating unit, two alternating threshold elements, a generator clock 55 pulses and two logic elements. And the first outputs of the first and second two-position switches are connected to the first and second connectors, respectively, in the recharger and network capacities do not reach the level (and speed) at which the signal is available in the monitored network, the output of the differentiating unit 13 and the threshold element 15 will disappear. From the first input of the logical element I 10 the high level signal will disappear Logical unit, instead the low level signal will appear Logical zero. The pulses from the generator 8 will cease to pass through the AND 10 logic element, the switch 1 will return to the initial state when the capacitor 5 is closed to low impedance 3. ment and 9 is fed to the controlled input of the switch 2. As a result, the capacitor 6 is connected in parallel to the insulation resistance 21, creating 8 clock pulses during the presence of a pulse from the generator, a low impedance channel of the accelerated recharging of the network capacitances, and in the pause between the pulses it discharges through low impedance resistor 4, i.e. The work proceeds according to the same algorithm, which is described for the case when the potential on the bus increases with respect to the ground. Invention Formula Electrical installation containing a DC power network consisting of a source of electrical energy, connecting buses, loads, feeder, control and measurement unit, the first input of which is connected This input is connected to the earth bus, which is different from the fact that, in order to improve the reliability of the electrical installation, it is additionally introduced with two two-position switches, two capacitors, two low-resistance resistors, a differentiating unit, two alternating threshold elements, a generator clock 55 pulses and two logical elements And, with the first outputs of the first and second two-position switches and - connected to the first and second connecting buses, respectively, second 714992808 The second outputs are connected to the first terminals of the low-voltage unit connected to the external resistance resistors, the second terminals are connected by a connecting bus, the second connectors are connected to the ground bus, the first and second logical inputs are connected to the output terminals of the main switches And connected to the output of the generator with the first terminals the first and second clock of the pulse pulses, the second (of a rigid capacitor, the second pins are co-equal), the input of the second switch is connected to the ground bus, l is connected to the output of the second the second () with the 1st input} of the first pe-ky element I, the first input of the switch is connected to the output of the first one connected to b1) by the second threshold of the logic element I, the first-element element whose input is connected to the output differentiating unit the threshold element, the input differential and the input of the first threshold element.