SU1312533A1 - Device for temperature diagnostic checking of stator winding of electric machine - Google Patents

Abstract

The invention relates to the control of the operation of an electric machine and can be used to diagnose parallel branches of the stator winding rods of powerful turbo-generators with direct water cooling, as well as to control the ratio of temperature differences between refrigeration and water-cooled units. The purpose of the invention is to increase the reliability of control by determining the cause and the overheating zone of the stator winding, taking into account the parameters of the load. The device contains the first sensors 1, the first functional converters 2, the switch 3, the block 4 key elements, the source 5 reference voltages, two 6t and 62 subtraction circuits, two reference digital converters 7i and 79, two registers 8i and 82, the element OR 9, first interface unit 10, microprocessor 11, operative 12 and permanent 13 memory devices, keyboard 14, thief interface unit 15, asymmetry factor measurement unit 17, first signaling unit 18, overheating driver unit 19, overheating reason signals 20, second unit alarm signaling unit 21, load measurement unit 22, detection unit 23, second temperature sensor 24, second functional converter 25, third temperature sensor 26, third functional converter 27 The effect of using the device is achieved by continuously calculating the relative heat load coefficient and comparing it to reference value, as well as prediction of the thermal state of the electric machine, taking into account the parameters of the load. 1 il. I (L o w o ate :) 00

Description

The invention relates to electrical machines and instrumentation engineering and can be used to diagnose parallel branches of the stator winding rods of powerful turbogenerators with direct water cooling, as well as to control the ratio of temperature differences between refrigeration and water-cooled units.

The purpose of the invention is to increase the reliability of control by identifying the cause of overheating of the stator winding of an electric machine, taking into account the parameters of the load.

The drawing shows the block diagram of the device.

The device contains the first temperature sensors 1, the first functional converters 2, the switch 3, the block of 4 key elements, the source 5 reference voltages, two analog subtractors 6i and 62,

ten

15

or relative reduction of water consumption of the cooling system, which leads to the development of excessive overheating of the winding, and then to a severe generator failure.

Thus, the device allows, by changing the coefficient Kj-, to reveal not only the complete blockage of the controlled branches of the stator winding, but also more subtle changes in the cooling mode of the controlled branch caused by overheating, occurring even with partial overlapping of individual channels in one of the winding rods, which provides prediction of the thermal mode of the electric machine.

Prediction of thermal conditions is carried out with the aim of identifying the cause and the overheating zone taking into account the change in load (load 50%, load 70%) and load unbalance (ratio asymmetry first 7i and second 72 analog-digital pre-20% 2%). the generators, two registers 8i and 82, the Technical Implementation element carried out 9 OR, the first interface unit 10, mixes the introduction of the load measurement unit 17, the unbalance factor measurement block 17 and the unbalance alarm unit 18, which forms a sign in the shaper of the overheating reason signals 19 asymmetry coefficient

CPU 11, random access memory 12, read-only memory 13, keyboard 14, second interface unit 15, timer 16, asymmetry factor measurement unit 17, first alarm unit 18 (asymmetry detector unit), overheating cause signal generator 19, display unit 20 .

25

2%. The block of level detectors forms signs in the display unit at a load of 50% and at a load of 70%, according to which 35

the second signaling unit 21 (the Q signaling unit from the keyboard sets the level sequence of the level), the load measurement unit 22,

a recording unit 23, a second temperature sensor 24, a second functional converter 25, a third temperature sensor 26, a third functional converter 27.

The device works as follows.

The introduction of second and third sensors of functional transducers makes it possible to monitor the water temperature at the inlet in the common water supply manifold to the stator winding and at the output of the winding to a 40 signal with a common drain collector. The combined use of the results of monitoring the first, second and third sensors allows the relative heat load of each parallel branch of the stator winding to be determined, which is expressed by the dimensionless 1M KI determined by the formula

the frequency and frequency of polling temperature sensors with a device that determines the value of K by means of a microprocessor of operative 12 and permanent 13 memory devices; and compares it with a predetermined base value of K, bases. The result of the comparison enters block 19 for fixing the cause of overheating, the first input of which receives a logical signal from the output of the first interface unit 10, corresponding to Ki Ki oaz and the second input of the logical output of signaling block 18.

The output of the imaging device 19 signals the causes of overheating the following logical signals are formed

45

TO; K, - ba when Ki Quasi,

The first corresponds to the increased heat generation due to the unbalance of the load, when the different phases of the stator winding are heated differently; the second is a complete or partial clogging of the stator winding rods, resulting in a relative decrease in the flow of water through the branch. Normalized by load level alarms, signs corresponding to a load of 50% and a load of 70% are fundamental in organizing the periodicity of monitoring the cooling mode of individual branches of a hydraulic system, for example

V „TCH.”

,

1g - 1o

(ABOUT

whereT (is the water temperature at the outlet of the i-ro branch of the branch;

TO is the inlet water temperature in the common water supply manifold to the winding; Tg is the water temperature at the outlet of the winding in the common drain manifold. An increase in K, —for any of the controlled branches, is a consequence of the increased heat release in the elements

five

or relative reduction of water consumption of the cooling system, which leads to the development of excessive overheating of the winding, and then to a severe generator failure.

Thus, the device allows, by changing the coefficient Kj-, to reveal not only the complete blockage of the controlled branches of the stator winding, but also more subtle changes in the cooling mode of the controlled branch caused by overheating, occurring even with partial overlapping of individual channels in one of the winding rods, which provides prediction of the thermal mode of the electric machine.

Prediction of thermal conditions is carried out with the aim of identifying the cause and the overheating zone, taking into account changes in load (load 50%, load 70%) and load asymmetry (coefficient of asymmetry 2%). The technical implementation is carried out by introducing into the device the load measurement unit 22, the asymmetry coefficient measuring block 17 and the asymmetry block 18 block forming a sign in the generator 19 of the overheating reason signals with the asymmetry factor

2%. The block of level detectors forms signs in the display unit at a load of 50% and at a load of 70%, according to which 35

 Q rator from the keyboard sets the sequence

40 signal s

the frequency and frequency of polling temperature sensors with a device that determines the value of K by means of a microprocessor of operative 12 and permanent 13 memory devices; and compares it with a predetermined base value of K, bases. The result of the comparison enters block 19 for fixing the cause of overheating, the first input of which receives a logical signal from the output of the first interface unit 10, corresponding to Ki Ki oaz and the second input of the logical output of signaling block 18.

The output of the imaging device 19 signals the causes of overheating the following logical signals are formed

40 signal s

45

TO; K, - ba when Ki Quasi,

The first corresponds to the increased heat generation due to the unbalance of the load, when the different phases of the stator winding are heated differently; the second is a complete or partial clogging of the stator winding rods, resulting in a relative decrease in the flow of water through the branch. Normalized by load level alarms, signs corresponding to a load of 50% and a load of 70% are fundamental in organizing the periodicity of monitoring the cooling mode of individual branches of a hydraulic system, for example

55

50% load - measurements are impractical due to low heat generation; load 57-70% - control view; load not less than 70% - with registration on the form. The load measurement unit 22 continuously measures the load of the generator (not shown) at its output terminals, and the asymmetry factor measurement unit 17 measures the load asymmetry, in particular, the current asymmetry in the phases of the stator winding of the turbogenerator. The signaling units 18 and 21 are threshold devices that generate corresponding logic signals in case of exceeding the specified settings - for a load of 50% and 70%, for an asymmetry factor of 2%, which are fed to the driver 19 of the overheating reason signals and the display unit 20. Depending on the generator load, the operator by

Zero scale offset error is controlled by connecting the inputs of analog switches 6 to the zero potential bus by means of a block of 4 key elements and g of determining bias coding slots Uo, Uo equivalent to No, NO codes obtained at the outputs of analog-to-digital converters 7. Digital codes No, NO is stored in registers 8, and then rewritten under the control of the microprocessor 10 11 in RAM 12.

By means of a block of 4 key elements, reference voltage from the source of 5 reference voltages is supplied to the non-inverting inputs of the subtractors, and the inverter and the rotating inputs are connected to the zero potential bus. Thus, at the outputs of analog-digital converters 7 there is a digital code of the reference signal, for which the exact value of the output code N ,, known in the block is known

keyboard 14 sets the frequency of polling 20 of the ROM 13. As a result of the signal conversion at the outputs of the analog-digital converters 7, codes Nj N, are formed which are stored in the buffer registers 8.

The microprocessor 11 calculates the correction factors to reduce the scale error for each analog-digital converter 7 according to the formulas

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temperature sensors using a programmable timer 16. Thus, according to the timer signals, microprocessor 11 automatically organizes a cyclical interrogation of sensors, calculating Kj followed by comparing digital codes with codes of base values Ksas. pre-stored in the persistent storage device 13 for each parallel branch of the cooling system, depending on the type of generator. K. are determined on the basis of the results of the thermal tests of the machine, carried out at the factory or the installation site of the generator.

The microprocessor, the programmable timer, the interface units, the RAM, the ROM are realized according to the typical application scheme of the K580 microprocessor set.

Block 4 of key elements contains several groups of key elements. The first group consists of three elements that connect the outputs of the second functional converters 25, 40 through the second input to the output of the switch 3 and the third input to the outputs of the third converters 27 to the corresponding inputs of the analog cogs 6. The second group consists of one key element connecting the input source 5 reference voltages to the inputs of analog subtractors 6. A third group consists of two key elements connecting a zero potential to the analog inputs

Mae - NO.

  N3 - N6

„,, Зз No. NO

(2)

(3)

35

45

Since microprocessor 11 at each duty cycle determines the coefficient K, the correction factor for calculating K is

M

W (4)

Thus, the exact value of the code K, in which the systematic errors of zero offset of the scale and scale are eliminated, are calculated by the microprocessor using the formula

- m IP) X - No (tg - That) X - Nb

(five)

where (T, - That) X and (Tr - To) x are digital voltage codes proportional to the multipliers 6. Key elements of the second Qst m of the indicated temperatures at the outputs of the ana- and third groups work in a cycle of autoclaves digital converters 7 when polling i-ro sensor.

The autocalibration process is performed once for one sensor polling cycle. The process of determining the relative heat In order to reduce the systematic load of each parallel branch of errors of the subtractors b and the A / D converter 7 is implemented as follows, the principle of autocalibration is applied to the microprocessor through the first interface signal. Initially, the liquidation block 10 issues a digital address code.

The device is calibrated, and the first group is in the duty cycles of controlling the relative heat load of the parallel branches of the cooling system.

25

about

Mae - NO.

  N3 - N6

(2)

„,, Зз No. NO

(3)

40

35

45

Since microprocessor 11 at each duty cycle determines the coefficient K, the correction factor for calculating K is

M

W (4)

Thus, the exact value of the code K, in which the systematic errors of zero offset of the scale and scale are eliminated, are calculated by the microprocessor using the formula

- m IP) X - No (tg - That) X - Nb

(five)

the controlled branch of the stator winding to the address input of the switch 3, as well as a control signal to the block 4 key elements for connecting to the inputs of analog subtractors 6 output voltages of functional converters 2 and 25, proportional to To, Tr-Ti. From the outputs of the subtractors 6, the voltage proportional to Tg - T and Ti- TO is fed to the inputs of analog-digital converters 7, the signal "conversion start (output of the first interface unit 10) is converted by analog-digital converter 7 to a digital code, and The termination of the conversion generated by the analog-to-digital converter 7 enters the buffer registers 8, and then into the microprocessor to calculate the value of K for the corresponding branch using formula (5), which is matched with the base Qbase.

The result of the comparison in the form of a logical signal enters the shaper 19 of the signal of the cause of overheating 19, in which two logical signals are generated that carry the following information: at K. C / n and Knes -2% - increased heat generation due to load unbalance, when different phases of the winding the stator is heated unequally; with K, - K / bases and 2% - a relative decrease in the flow of water through the branch.

These signals, as well as the numerical codes for the computational value of K, and K, -Vaz are fed to block 20 nidicacin. The registration unit 23 receives the digital codes of the channel address, the computational value of K; and real time.

Thus, the device provides the calculation of the relationship of temperature differences T, -To and Tr-TO, comparing the obtained digital codes of the dimensionless coefficient of relative thermal load K; each parallel branch of the cooling system with digital codes of basic values K, аз az, used in ROM 13, and also generates logical signals that carry information about the causes of overheating of the stator winding of the turbogenerator taking into account the parameters of the load, which allows prediction the thermal state of the machines and timely carry out the elimination of irregularities, not bringing them to the development of a severe MaiHHbi accident.

Claims (1)

Invention Formula Device for temperature diagnostics of the stator winding of an electric machine containing the first temperature sensors, connected / outgoing outputs to the inputs of the corresponding first functional converters connected by the outputs to the corresponding information inputs of the switch, the source of reference voltages, the first analog-digital converter, the display unit and the recording unit , characterized in that, in order to increase the reliability of the control by determining the cause of the overheating of the winding stator taking into account the parameters of the load, the second and third temperature sensors, the second and third functional converters, the block of key elements, the second analog-to-digital converter, two analog subtractors, two registers, a keyboard, two interface blocks, random access memory, Permanent memory, OR element, timer, overheating cause driver, block 5 unbalance factor measurements, a load measurement unit, two signaling units and a microprocessor connected by information control and address inputs-outputs with informative, control and address inputs of the operational and persistent storage, the timer, the first and second interface blocks, respectively , information and control inputs of the first and second registers connected by information inputs with the outputs of the first and second analog-digital converters, respectively connected by information inputs with outputs of the first and second analogue-Bbix subtractors, respectively, and control inputs, with the first output of the first interface unit connected by the second output to the first input of the OR element and to the second control unit input of the key element unit, the third output - to the second input of the OR element and to the third control; 5 the theme of the input of the block of key elements; the fourth output - to the first control input of the block of key elements, the fifth output - to the control inputs of the first and second control strov, schestym 0 output to the first input of the display unit and to the input of the registration unit, the seventh output to the address input of the switch, and the eighth output to the first input of the overheating cause signal connected to the second BXO; I.OM with the output of the first alarm unit, and the first and second outputs, respectively, with the second and third inputs of the display unit connected by the fourth and fifth outputs, respectively, to the first and second outputs of the second signaling unit connected by the input to the first output of the load measuring unit, a second output to the input of the measurement unit of the coefficient of symmetry, associated with the output to the input of the first signaling unit, and , the output of the second functional converter is connected to the first information input of the block of key elements connected by the second information inputs 1312533 78 with the switch output, the third with the second, fourth and fifth outputs of the information input with the output of a third of the key elements, the third output with its functional converter than with the second inputs of analog subtractors by twist information input - from the output and with the sixth output of the key block of the power source of the source of reference voltages, n -5 cops, the outputs of the second and third sensors The sixth and sixth information inputs are temperatures connected respectively to with a tire of zero potential of the device, the inputs of the second and third functional the first output is with the first inputs of the converters, and the output of the keyboard of the basement and the second analog subtractors and keys to the input of the second interface unit.