SU1465830A1 - Method of comprehensive monitoring of three-phase winding of electric machine - Google Patents

Abstract

The invention relates to the field of electrical measuring equipment and can be used in the control of inter-turn insulation and the detection of short circuits in the winding of asynchronous electric machines. The purpose of the invention — to increase the reliability of the control — is achieved by increasing the sensitivity and closing of one turn. The method is based on the dynamic features of the superposition spectra of two pole sequences supplied from a pulse generator to the phase windings. A device that implements the method contains a pulse generator 1, a differential amplifier 2, a selective unit 3, a voltmeter 4 control object 5, pins 5.1, 5-2 and 5.3 phase windings. The invention makes it possible to increase the sensitivity of this method by an order of magnitude and thereby increase the reliability of the control as compared with the known one. 3 il. h 3 ate

Description

one

The invention relates to electrical measuring technique and can be used to control inter-turn insulation and detect short-circuits in the winding of asynchronous electric machines.

I

The purpose of the invention is to increase the reliability of control by increasing the sensitivity and closure of a single turn.

Figure 1 presents a device that implements the proposed method; Fig. 2 shows time diagrams of voltages explaining the operation of the device; in fig. 3 - frequency characteristics and amplitude spectra, which explain the operation of the device.

The device implementing the method contains a pulse generator 1, a differential amplifier 2, an electoral unit 3 and a voltmeter 4. The first lead of the generator 1 is connected to the first lead of the first phase winding 5.1 of the object 5 of the control, the second lead is connected to the first leads of the second 5о2 and the third 5оЗ phase windings of the object 5 control. In addition, the first output of the first winding 5-1, the second conclusions of the second 5.2 and third 5.3 windings of the object 5 of the control, are connected respectively with per4: O5 SP

00

oo

Vym, the second, the third pins of the amplifier 2, the outputs of which through the selective unit 3 are connected to a voltmeter 4 o

The proposed method is based on the dynamic features of the superposition spectra of two pulse sequences fed from a pulse generator to the phase windings. In isp-Yu to defects and the corresponding arc-equals and an electrical filter with a pulse difference. Increasing the time of personal combinations of the positions of the phase windings of the frequency of the maximum frequency characteristics differ no more than the amplitude spectrum by 0.2%. If in one of the phases there are 15 figs. Zg, before the amplitude decreases, short-circuited threads occur, then from the Fixed harmonic to zero in the frequencies of the maximum frequency characteristic of the impedance module of the resonant selection20

the spectrum supplied from the generator 1 of the pulse sequence at tj 0; c) the amplitude spectrum of the vector voltage difference at the output of the differential amplifier 2. Record the corresponding harmonic as the most sensitive one at the maximum reading of the voltmeter 4

delays t, j between the pulse sequences (Fig. 2a), to which the amplitude spectrum corresponds

The effective circuit containing the resonant circuit from the windings of the phases and the differential amplifier is 8–10%, and the maximum values themselves increase by a factor of 10. The use of these effects in the proposed method led to an increase in sensitivity by no less than an order of magnitude. The method of coaxial control of the three-phase winding is carried out as follows.

A superposition of two pulse sequences with the same periods is applied to the windings of the electrical magaiish from the generator (Fig. 2b). Set the delay time between said pulse sequences t .0, (Fig. 2a). Change the duration of the pulses in the pulse sequence of the generator I and rearrange the tuning frequency of the electoral unit 3, adding (according to the maximum reading of the I voltmeter 4) placement of the resonant frequency of the winding between the corresponding first and second zero amplitude test voltage (combined pulse sequence) o The result of this adjustment, which consists in combining the harmonics corresponding to the middle between the first and second zero of the amplitude spectrum with the frequency max. The amplitude-frequency characteristic at the output of the differential amplifier 2 is shown in Fig. 3a, b, c, where a) the amplitude-frequency characteristic of the vector difference of voltages at the output of the differential amplifier 2; b) amplitude

(fig.Zd). Phase windings are successively interchanged, and by the change (increase) in the amplitude of the recorded harmonic (according to the indication of a voltmeter 4), a defect is detected in the corresponding winding.

The invention increases the sensitivity of the method and, consequently, the reliability of control (especially when one coil is closed), and the use of pulsed voltage as a test voltage makes it possible to simultaneously test inter-turn insulation, resulting in improved product quality .

Claims (1)

Invention Formula 35 The method of complex control of a three-phase winding of an electric machine, based on the supply of test voltage between the corresponding output of the first phase winding and the same name or the opposite terminals of the second and third phase windings, measuring, respectively, the voltages between the specified output and the wake outputs of the second and third phase windings, to obtain the vector difference of the measured voltages, about t - which is due to the fact that, in order to increase the reliability of the coit50, a test voltage is applied as a test voltage a superposition of two sequences of pulses with identical periods, establish a zero delay between the specified 55 sequences of pulses, change the duration of the pulses, until the resonant frequency of the windings is located between the corresponding first and second zero frequencies. to defects and the corresponding pulseability of pulses. The amplitude spectrum in Fig. 3 increases the time, until the amplitude of the fixed harmonic decreases to zero. the spectrum supplied from the generator 1 of the pulse sequence at tj 0; c) the amplitude spectrum of the vector voltage difference at the output of the differential amplifier 2. Record the corresponding harmonic as the most sensitive one at the maximum reading of the voltmeter 4 to defects and the corresponding pulseability of pulses. The amplitude spectrum in Fig. 3 increases the time, until the amplitude of the fixed harmonic decreases to zero. delays t, j between the pulse sequences (Fig. 2a), to which the amplitude spectrum corresponds Yu to defects and the corresponding pulseability of pulses. The magnitude of the amplitude spectrum increases by 15 in Fig. 3g, until the amplitude of the fixed harmonic decreases to zero - 0 (fig.Zd). Phase windings are successively interchanged, and by the change (increase) in the amplitude of the recorded harmonic (according to the indication of a voltmeter 4), a defect is detected in the corresponding winding. The invention increases the sensitivity of the method and, consequently, the reliability of control (especially when one coil is closed), and the use of pulsed voltage as a test voltage allows you to simultaneously test inter-turn insulation, resulting in improved product quality . Invention Formula five The method of complex control of a three-phase winding of an electric machine, based on the supply of test voltage between the corresponding lead of the first phase winding and the same pin or the opposite terminals of the second and third phase windings, measuring, respectively, the voltages between the specified output and the second and third terminals phase windings, obtaining the vector difference of the measured voltages, about t - which is due to the fact that, in order to increase the reliability of the coitol, as a test voltage under by superposition of two pulse sequences with the same periods, establish zero time delay between the E ukazanny5 sequences of pulses, the pulse duration is varied, achieving Referring arranging the resonance frequency between the respective windings - s at the first and second frequency zero. the amplitude spectrum of the test voltage; from the vector difference of the measured voltages, the harmonics are successively selected from the first to the second zero of the amplitude spectrum, while simultaneously changing the pulse duration, at the same time, locating the harmonic in the middle between the first and second zero of the amplitude spectrum and determining the harmonic, whose amplitude maximally fixes this harmonic, increases the delay time, until the amplitude of this harmonic decreases to zero, successively interchange the two phase windings, measure the amplitude of the harmonics recorded above and, from its zero level, judge the presence of a closure in winding. / / 5.2 X 5L hours l 5.3 / X IL FI.2  o / 7ff j of7at2 fJfJofJoTz FIG. B Ujgn SHOP