SU840766A1 - Device for measuring dc network insulation - Google Patents

Description

(54) DEVICE FOR MEASURING RESISTANCE

INSULATION OF ELECTRIC NETWORK NETWORK. CURRENT

Yes, the memory blocks, the inputs of the intermediate gauges are connected to the third and fourth switches of the switch, the fifth and sixth outputs of which are connected to the input of the measuring unit, the inputs of the memory blocks are connected to the fifth and sixth outputs of the switch, the second output of the additional resistor, and also non-switched inputs of two intermediate meters - drives and two storage blocks are connected to the housing (ground).

As a measuring body, a zero-body was used, the second input of which is connected to the phase of the monitored network and to the moving contact of the variable resistor connected between the phases of the network being monitored, and the output to the signal lamp and to the input of the control unit whose output is connected to the moving contact through the actuating motor variable resistor.

In addition, a second null-organ is introduced; a second variable resistor and a second signal lamp; the second input of the second null-organ is connected to the fifth and sixth outputs of the switch; the second input of the second null-organ is connected to the phase controlled network and to the moving contact of the second variable resistor connected between the phases of the monitored network, and the output of the second zero-organ is connected to the second signal lamp.

The drawing shows the functional diagram of the device.

The device connected to the controlled network 1 with the U voltage source and the resistances R and R.2 n3O of the pole, contains an additional resistor 2, a switch 3, an intermediary measuring accumulators 4 and 5, memory blocks 6 and 7, measuring the organ which can be used as a voltmeter or the first null organ 8, the second nutsch organ 9, the first variable resistor 1O, the second variable resistor 11, signal lamps 12 and 13, the control unit 14, the executive motor 15, while the switch has three pairs of changeover contacts 16-1 7, 18-19, and 2 O-21, and the pee-rass resistors 1 O and 11 are provided with pimbas for estimating the movement of a moving contact.

The device operates in periodic measurement, continuous measurement or automatic control modes.

In the periodic measurement mode, the 14 m 15 blocks are not connected, and the operation proceeds as follows.

Switch 3 (automatically or manually) periodically using the disconnecting contacts 16 and 18 connects the additional resistor 2 and intermediate meter-drive 4 to the positive pole of the network 1, while contacts 17,19 and 20 are open and contact 21 is closed. Thus, when the switch is in this position, an additional resistor 2 and an intermediate meter-storage device 4 are connected to the positive pole of the network 1. The voltage of the positive pole of the network 1 about the ground with the connected additional resistor 2 is fixed on the intermediate meter-accumulator 4.

In the next measurement stage, the switch 3 is moved to the position when the contacts 16, 18 and 21 open, and the contacts 17, 19 and 20 close. The add-on resistor 2 and the intermediate meter 5 are connected to the negative pole of the network 1. The voltage of this pole relative to the housing with the added resistor 2 is fixed on the intermediate meter-accumulator 5. Simultaneously, the voltage fixed on the intermediate meter-accumulator 4 is written to the storage unit 6

The return of commutary 3 in

the initial position, when the contacts 16, 18 and 21 are closed and open with the contacts 17, 19 and 20, the voltage from the intermediate meter - accumulator 5 is written into the storage unit 7.

Thus, after each subsequent switching stage, the sum of the stresses of the pole (W of network 1 relative to the housing, which take place at the moment when the additional resistor 2 is connected to each pole) is applied to the first input of the zero organ 8, the value of the equivalent insulation resistance of the network being determined by expression

u- (u, 4U2;

(one)

U.-VU.

where r /

Claims (3)

the value of the additional resistor 2; and - the operating voltage of the monitored network 1, t / and the IL-voltage (potentials) of the poles of the network 1 relative to the housing at the moments of shunting the insulation resistance of each popgap with an additional resistor 2. Those. the first input of the zero-organ 8 p is the voltage and and KD The voltage applied to the second input of the null-organ 8 is defined as (where RP is the resistance of the variable resistor 10; resistance of the shoulder resistor 1O between the moving contact and the output, the moving contact of the variable resistor 1O at U from the expression of the equality U of the stresses (2) and (3) follows th, (i.e. the value of the insulation resistance of the network, 1 is determined by the estimate of the movement R3-f (): f (- (L) -fCe,) (5) where U is the length of the active h The characteristics of the variable resistor 1O, t, are the length of movement of the moving contact of the variable resistor 10. The limb is graduated according to equality (5). The moment of achieving equality and and is fixed by the lighting of the signal lamp 12. In the continuous measurement mode, the operation of the circuit is similar to periodical measurement, but the movable contact of the variable resistor 10 perm 4 is automatically actuated by the electric motor 15 to a position corresponding to its equality (C /, when reached, the control unit 14 in accordance with 766 by a signal of a zero-organ 8 gives the motor 15 a stop. The insulation resistance value is also determined by the variable resistor limit Y. In the automatic control mode, you need to set the device setting value manually by the variable resistor limit, 11, while the second input is zero - organ 9 is supplied with the corresponding voltage U, if the value of the insulation resistance of the network 1 differs from the pick-up value, then the voltage at the inputs of the zero-organ 9 is not equal to 4 and. When the insulation resistance of the network 1 decreases to the value of the set point, the first input of the zero-org by 9 is supplied by the voltage U. UK. „., THAT leads to the appearance of a signal at its output and the signal lamp 13 triggers. the effect of the invention is to reduce the methodological measurement error as a result of the independence of the measurement of the insulation resistance from the voltage of the monitored network. Claim 1, A device for measuring the insulation resistance of an electric network of direct current, containing an additional cut torus, a measuring unit and a switch connected to the phases of the monitored network, the first pin of the additional resistor is connected to the first and second switches of the switch By the fact that, in order to improve accuracy by reducing the methodological error of measurements, two intermediate measuring instruments, a storage device, and two storage units were introduced, with the inputs of intermediate measuring devices accumulating lei e podkpyu us, respectively, to the third and Thu | To the switch outputs, the fifth and fifth outputs of which are connected to the input of a special organ, the inputs of the storage units are connected to the fifth and sixth outputs of the switch, the second output of the additional resistor, as well as non-switched inputs of two intermediate gauges and two memory memories. blocks are connected to the body (ground). . 2. Device by. Clause 1, that is, with the fact that a null-ay is used as the measuring organ, the second input of which is connected to the phase of the controlled network and to the moving contact of the nepovjeHHoro resistor connected between the phases of the monitored network, and the output with the signal | ampa and with the input of the control unit, the output of which is connected via an executive motor to a moving contact of the nepavte resistor. 3. The device in accordance with Claims 1 and 2, echoing the fact that a second null-organ, a second variable resistor, and a second signal lamp are introduced; The first input of the second nup organ connects to the fifth and sixth outputs of the comm The second input of the second null organ is connected to the phase of the monitored network and the moving contact of the second variable resistor connected between the phases of the monitored network, and the output of the second null organ connected to the second signal lamp. Sources of information taken into account in the examination 1.Shpenko EF. Isolation control in sets up to 1000 V.M., Energie, 197 s. 138-139. 2. In the same place 132-134 (prototype).