SU1219986A1 - Apparatus for inspecting insulation by earthing to frame of stator winding of water cooled synchronous operating generator - Google Patents

Abstract

This invention relates to an instrumentation technique and can be used at an electrical station to detect deterioration of the dielectric state of the insulation. The purpose of the invention is to increase accuracy and reliability. The device contains a measuring transformer 1, a shunt capacitor 2, ballast resistors 3 and 8, measuring shunts 4 and 7, power supplies 5 and 9 of constant voltage, sensor 6 salimeter, scale amplifiers 10 and 11, differential amplifier 12, recording element 13, threshold element 14, and alarm element 15. The introduction of two measuring shunts, a salimeter sensor, two large-scale amplifiers, a recording and a threshold element into the device made it possible to increase sensitivity by two orders of magnitude and to ensure high reliability of the insulation control on the stator winding of the generator. 1 il. to with; about 00 O)

Description

one

The invention relates to instrumentation technology and can be used at an electrical station to detect deterioration of the dielectric state of the insulation on the stator winding housing of a generator cooled with distant and operating in a unit with a transformer.

The purpose of the invention is to increase precision and reliability.

The drawing shows a block diagram of the device.

The device contains a shunt capacitor 2 connected to the measuring transformer 1, the first ballast resistor 3, the first measuring shunt 4, the first constant voltage source 5, the salimeter sensor 6, the second measuring shunt 7, the second ballast resistor 8, the second constant source 9 voltage, the first large-scale amplifier 10, the second large-scale amplifier 11, the differential amplifier 12, the recording element 13, the threshold

element 14, element 15 alarm. I

At the same time, the output of a constant voltage source through a ballast resistor is connected to the common end of the primary windings of the measuring voltage transformers and the outlet of a shunt capacitor, the second end of which is connected to a grounded common bus and through the first measuring shunt connected to the second output of the constant voltage source the first input of the first large-scale amplifier, and is directly connected to the first output of the salimeter sensor, the second output of which is connected to a grounded common bus and through the first measurement The potential shunt -j is the second output of a constant voltage source and the first input of the first large-scale amplifier, and is directly connected to the first output of the saltmeter sensor, the second output of which is connected to the first output of the second constant voltage source through the second ballast resistor, the second output of which is through the second The measuring shunt is connected to a grounded common bus, and directly connected to the first input of the second large-scale amplifier, the second input of which is connected to a grounded common bus, with which nen second input of the first

199862

scale amplifier, the output of which is connected to the first input of the differential amplifier, the second input of which is connected to the output of the second 5 scale amplifier, and the output is connected to the input of the recording element and the input of the threshold element, the output of which is connected to the input of the alarm element.

10 The device works as follows.

Resistance between electrodes,

saline gauge I

 RC - P - P.

15 because the sensor is manufactured in such a way that the distance between the electrodes is cm, their area is Sg 1 cm, and J) is the specific resistance of the distillate. Large-scale amplifiers, and a differential amplifier and threshold element are implemented on the micro-integrated circuits K553UD2 and K554SAZA.

25 Under the action of the voltage Ug of the source 5 through the primary windings of measuring voltage transformers and the equivalent resistance of the stator winding to the housing flows

thirty

f

Uc

R.

and v-r; .. r, .r,

cutting sensor salimeter under the action

voltage U source 9 - current

Ug and,

35 - -EH: R, R3 + R, and R, R, + Rg. As a result, voltages are supplied from measuring shunts to the inputs of large-scale amplifiers: and, l3-Rj Ug

40 c. i-) and U I R Ug R,. -1- if

Ra

.P

R .. R

ek + p-outputs

u e

These amplifiers and, accordingly, voltage U U K appear on the inputs of the differential amplifier

u. R, (- 4a "VU.K ,,

U.R7-5- with given coefficients R & .

amplifiers of scale amplifiers and K, where, is the design factor of the generator, E is its length, S and p is the cross section

and the number of water supply hoses on the head and drain. Then at the output of the differential amplifier, the voltage C is obtained, (U., o-Hii)

 to ,, - inn

one

if the conditions of equality of the voltage sources and shunts resistance, i.e.

U5 and ,, and and

m 7

The gain of the differential amplifier sets the measurement limits of a recording instrument, the scale of which is graduated

 MOhm In normal mode, i.e. at

The normal condition of the insulation of the windings and its cooling distillate, the difference in voltages at the outputs of the scale amplifiers and the inputs of the differential amplifier is small and is determined only by a small component of the current through the insulation of the windings. The voltage caused by the component of the current through the cooling distillate is compensated by the voltage from the current through the salinometer sensor. In this case, a voltage arises at the output of the differential amplifier, which corresponds to the normal isolation level.

If the dielectric state of the insulation deteriorates, for example, when it is wetted, the current component through the winding insulation increases. As a result, the difference in voltages at the input of the differential amplifier, the voltage at its output, which is indicated by the recording element, increases. An increase in readings indicates an increase in conductivity or, accordingly, a decrease in the level of insulation. When the voltage on the differential amplifier code reaches a predetermined level determined by the requirements of operation, it triggers the threshold element and the alarm element warns the staff about the dangerous deterioration of the insulation condition.

During normal isolation and deterioration of the cooling distillate, for example, its contamination, the increase in the component of the current through the distillate is compensated by an increase in the current through the salinometer sensor, since in both cases this is caused by the same factor — the decrease in the distillate resistivity .

As a result, the difference in voltage at the output of the differential amplifier and the recording element pos12199864

This is what indicates a constant level of isolation.

Claims (1)

Invention Formula ten 15 20 25 thirty 35 40 45 50 55 A device for insulating a synchronous generator with water cooling in the operating mode on the casing of the stator winding, comprising a first terminal of a shunt capacitor, the second terminal of which is connected to a grounded common busbar, connected to a common terminal of the primary windings of the measuring voltage transformers. the first output of the first constant voltage source, the differential amplifier, the second ballast resistor, the alarm element, the second constant voltage source Nor, in order to increase accuracy and reliability, two measuring shunts were introduced, a salinometer sensor, two large-scale amplifiers, a recording element, a threshold element, the second one of the first ballast resistor connected to the first output of the shunt capacitor, the second through which the first The measuring shunt is connected to the second output of the first constant voltage source and the first input of the first large-scale amplifier and is directly connected to the first output of the salinometer sensor, the second output is cat The second is connected via a second ballast resistor to the first output of a second source of constant voltage, the second output of which is connected via a second measuring shunt to a grounded common bus and directly connected to the first input of a second large-scale amplifier whose second input is connected to a grounded common bus to which the second input of the first large-scale amplifier, the output of which is connected to the first input of the differential amplifier, the second input of which is connected to the output of the second large-scale amplifier, and the output d is connected to an input of the recording element and the input of the threshold element whose output is connected to the input of the alarm element. Hjl Editor P. Tsitsika Compiled by Y. Karaev Tehred V. Kadar Proofreader E. Sirohman Order 1319/53 Circulation 728 Subscription VNIIPI USSR State Committee for inventions and discoveries P3035, -Moscow, Zh-35, 4/5 Raushsk nab. Branch PPP Patent, Uzhgorod, st. Design,