SU1176265A1 - Device for testing resistance of electric circuit insulation - Google Patents

Abstract

DEVICE OF CONTROL OF RESISTANCE OF ELECTRIC NETWORK INSULATION, containing a shunt resistor, the first output of which is connected to the combined outputs of niepBoro and the second keys, the inputs of which are connected to the poles of the monitored network, the second output of the shunt resistor is connected to the housing (ground), four storing elements, zero organ, four storing resistor, zero input, four shunt resistor connected to the housing (ground), four storing elements, zero organ, four storing resistor, connected to the housing (ground), four storing elements, zero organ, four storing resistor, connected to the housing (ground), four storage elements, zero organ, four storing resistor, connected to the housing (ground), four storing elements, zero organ, four storing resistor, connected to the housing (ground), four storing elements, zero organ, four storing resistor, connected to the body (ground), four storing elements, zero organ, four storing resistor, connected to the housing (ground), four storing elements, zero organ, four storing resistor, connected to the body (ground), four storing elements, zero organ, four storing resistor. the third input of which is connected to the moving contact of the variable resistor, one fixed output of which is connected to the negative pole of the controlled network and to the fourth input of the zero-org a, the first input of which is connected via serially connected third and fourth keys to the positive pole of the monitored network and to the input of the third storage element, the second input - via serially connected fifth and sixth keys to the negative pole of the monitored network and to the input of the fourth storage element, another fixed the output of the variable resistor is connected to the positive pole of the network, the inputs of the first and second storage elements are connected respectively to the outputs of the fourth and sixth keys, other inputs of storage elements are combined and connected to a housing (ground), a control unit, the first output of which is connected to the control inputs of the first, fourth and fifth keys, the second (L output - to the control inputs of the second, third and sixth keys , in contrast to the fact that, in order to increase the control efficiency, a series-connected adder, an amplifier-limiter with a coding element, a seventh key, a faulty network pole indicator, a control input of the seventh key are connected to the output s-body adder inputs connected respectively to the outputs of third and fifth keys, a third adder input connected to the housing (ground), the input control unit connected to the bus starts.

Description

one . The invention relates to electrical measuring equipment and can be used to detect the smallest insulation resistance of network poles relative to a common bus electrical networks of direct current under voltage to determine a faulty pole network. The purpose of the invention is to increase the efficiency of monitoring the detection of an inoperative pole. networks by detecting the smallest of the resistances of the insulation of the network poles,. The drawing shows a functional diagram of a device for monitoring the insulation resistance of an electrical network. The device contains an electrical network 1, a shunt resistor 2, keys 3 and 4, an adder 5, a key 6, an amplifier-limiter 7, memory elements 8 and 9, keys 10 - 12, memory elements 13 and 14, a key 15, an indicator 16 faulty power poles, null organ 17, control unit, start bus 19, variable resistor 20. I. . In the device for controlling the resistance of the insulation, the poles of the electrical network 1 are connected via switches 3 and 4 to the first terminal of the resistor 2, the second terminal of which is connected to the housing to which the second inputs of the storage elements 8, 9, 13, 14 and the third input are also connected. adder 5, the first input of the storage element B is connected to the output of the key 6 and the input of the key 12, the first input of the storage element 9 is connected to the output of the key. 10 and the key input 15, the key inputs and 6 are connected to the positive pole of the electric network 1, and the inputs of the keys 4 and 10 are connected to the negative field of the network 1, the fixed output of the variable resistor 20 is connected to the negative pole of the electric network 1, the outputs of the keys 12 and 15 connected respectively to the inputs of the storage elements 13 and 14 and to the first and second inputs of the null organ 17, the third and fourth inputs of the latter are connected to the moving contact of the resistor 20 and to the negative pole of the network, respectively, the first and second inputs of the adder 5 are connected to the outlets With the keys 12 and 15, the output of the adder 5 is connected to the input of the amplifier-limiter 7, 652 with the coding element, the output of which is connected to the input of the key 11, and the output of the latter with the indicator 16 of the faulty network pole that controls the keys 3, 6, 15 and the keys 4, 10, 12 are connected respectively to the first and second outputs of the control unit 18, the input of which is connected to the start bus 19, the output of the null organ 17 is connected to the control input of the key 11. Amplifier limit switch 7 can be performed on the operational amplifier 544 series without feedback. The coding element can be a voltage level converter for converting an operational amplifier into voltage, corresponding to 1 and O i block 18 controls a square pulse generator, made on a TTL, the pulses of which enter the logic circuit, and the outputs of the latter are connected to relay windings which switch the keys 3, 4, 6, 10, 12 and 15.. The principle of operation of the device. The following is concluded. According to the trigger signal received from the startup bus 19 to the control unit 18 at the time t 0, the control pulse control unit 18 connects the positive pole of the network 1 periodically with the key 3 to the shunt resistor 2 and the storage element 8, while the keys 4, 10 and 12 are open, and keys 3, 6 and 15 are closed. The voltage of the positive pole of the network 1 relative to the housing when connected to a resistor 2 is fixed on the storage element 8 and is equal to Rui Ri and 1 - c7r-tg; (where R is the insulation resistance of the positive pole of the electric network 1 relative to the case; Rj is the insulation resistance the negative pole of the electrical network 1 relative to the housing; (c is the shunting resistance of the resistor 20; and is the voltage of the electrical network 1.

31

In the next measurement period, the control unit 18 opens the keys 3, 6 / and-15, and the keys 4, 10 and 12 closes. The shunt resistor 2 and the storage element 9 are connected to the negative pole of the network 1. The voltage of this pole relative to the housing with the shunt resistor 2 connected is fixed on the storage element 9 and is equal to

 and

2 ()

At the same time, the voltage fixed on memory element 8 is rewritten into memory element 13. In the next measurement period, keys 3, 6 and 15 are closed and keys 4, 10 and 12 open, the voltage from memory element 9 is rewritten into memory element 14. .

After each switching step, the sum of the voltages is applied to the first two inputs of the zero-body 17, and U is then fed to the inputs 3 and 4 of the nullan 17 with the variable resistor 20 a reference voltage corresponding to the threshold value of the equivalent insulation resistance

"". if: |; - about ("

  + and

(4) with respect to U + Uj,, half

Ksh

+ and

and

+ RW

R

3ke

762654

From formulas (5) and (3) it is gzidno that for control Rp ((5 it is enough to compare and + Uj with the reference voltage Upr,

Simultaneously to the inputs of the adder 3 5. the voltages are supplied from the storage elements 13 and 14. The adder 5 adds the values of these voltages, which is equivalent to subtracting the moduli of the values of these voltages

| „,, Chi ,,. | - | - -; LB (6,

Then it follows that if lUv, | - | U2l 1 .0, then R.- Rj 0, therefore Rj, i.e. the + sign corresponds to a lower insulation resistance of the subtracted pole of the network 1 (negative pole); if (U2KO, 0 then R - Rj 0, therefore R.R2,) i.e. the sign corresponds to a lower insulation resistance that subtracts | the poles of network 1 (positive i poles).

The result goes to the amplifier-limiter 7 with a coding element that produces a force with the output signal limited by the adder 5 and converts the saturation voltage levels of the amplifier-limiter

7 in voltage corresponding to 1

or O, and the output signal of the latter is fed to the input of the indicator 16 of the faulty network pole through the key

5 11 and indicator 16 is faulty

The network poles indicate which of the poles of network 1 has a lower insulation resistance.

Claims (1)

ELECTRICAL NETWORK INSULATION RESISTANCE CONTROL DEVICE, comprising a shunt resistor, the first terminal of which is connected to the combined outputs of the first and second switches, the inputs of which are connected to the poles of the controlled network, the second terminal of the shunt resistor is connected to the housing (ground), four memory elements, zero-organ, the third input of which is connected to the movable contact of the variable resistor, one fixed output of which is connected to the negative pole of the controlled network and to the fourth input of the zero-organ the first input of which is connected through series-connected third and fourth keys to the positive pole of the controlled network and to the input of the third memory element, the second input - through series-connected fifth and sixth keys to the negative pole of the controlled network and to the input of the fourth memory element, another fixed pin a variable resistor is connected to the positive pole of the network, the inputs of the first and second storage elements are connected respectively to the outputs of the fourth and sixth keys, these inputs of the storage elements are combined and connected to the housing (ground), a control unit, the first output of which is connected to the control inputs of the first, fourth and fifth keys, the second output - with the control inputs of the second, third and sixth keys, characterized in that, in order to increase the control efficiency, a series-connected adder, an amplifier-limiter with a coding element, a seventh key, an indicator of a faulty network pole, a control input of the seventh key are connected to the output of a zero-organ, the sum inputs ora connected respectively to the outputs of third and fifth keys, a third adder input connected to the housing (ground), the input control unit connected to the bus starts. SU_, ·, 1176265 1 . eleven