Hydro-generator stator cross-core screw-positioning rib short circuit fault monitoring system

Abstract

The utility model discloses a hydro-generator stator cross-core screw-positioning rib short circuit fault monitoring system, which relates to the technical field of generators and comprises a measuring unit and an alarm system arranged between a cross-core screw and a positioning rib. The measuring unit comprises a first voltmeter and a second voltmeter, one end of the first voltmeter is connected with one end of the through screw, the other end of the first voltmeter is grounded, and two ends of the second voltmeter are respectively connected with two ends of the through screw. The first voltmeter can measure the voltage of the upper end of the cross-core screw to the ground, the second voltmeter can measure the voltage of the upper end of the cross-core screw to the lower end of the cross-core screw, the two ends of the cross-core screw are directly connected, on-line collection of voltage data on the cross-core screw is achieved, the alarm system is arranged between the cross-core screw and the positioning rib, and the alarm effect is improved. Alarm can be carried out when a short-circuit fault occurs to the cross-core screw.

Description

Technical Field

[0001] The utility model relates to the technical field of generators, in particular to a short-circuit fault monitoring system for a stator through-core screw rod and a positioning rib of a hydro-generator. Background Art

[0002] With the advancement of modern science and technology and the continuous expansion of the scale of energy systems, motors play an increasingly important role in modern industrial production. Motor failure will not only damage the motor itself, but also interfere with the normal operation of the entire system, causing huge economic losses and huge social impacts. Among them, the characteristics of the cross-flow turbine generator are low speed, small space, and the limitation of the diameter of the bulb body. The electromagnetic design, structural design, and operation and maintenance are difficult. If there is any misconduct, it is very likely to cause serious failures. At present, there are mainly the following methods for monitoring the short-circuit grounding fault of the through-screw-positioning rib of the turbine generator: 1. Use a megohmmeter to measure the insulation resistance 2. Detect the current on the through-screw 3. Detect the current on the positioning rib facing the through-screw.

[0003] In the prior art, insulation resistance measurement using a megohmmeter needs to be performed when the generator is stopped, and online measurement of data cannot be achieved. When the current measurement method is used, two-point grounding faults cannot be discovered in a timely and effective manner, and there is no alarm prompt, so maintenance personnel cannot handle it in time, which increases maintenance time and poses more risks. Utility Model Content

[0004] Aiming at the problem that the prior art cannot timely collect the relevant data of the through screw online and issue an alarm in time, the utility model provides a short-circuit fault monitoring system for the through screw-positioning rib of a hydro-generator stator.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A short-circuit fault monitoring system for a through-screw and a positioning rib of a hydro-turbine generator stator, the system comprising a measuring unit and an alarm system, the alarm system being arranged between the through-screw and the positioning rib; the measuring unit comprising a first voltmeter V1 and a second voltmeter V2, one end of the first voltmeter V1 being connected to one end of the through-screw, the other end of the first voltmeter V1 being grounded, and both ends of the second voltmeter V2 being respectively connected to both ends of the through-screw. The first voltmeter V1 can measure the voltage of the upper end of the through-screw to the ground, and the second voltmeter V2 can measure the voltage of the upper end of the through-screw to the lower end. By directly connecting the two ends of the through-screw, online collection of voltage data on the through-screw is realized, and by arranging an alarm system between the through-screw and the positioning rib, an alarm is issued when a short-circuit fault occurs in the through-screw.

[0007] Further, the alarm system includes a circuit board, which includes a main processor, a voltage transformer, a signal conditioning circuit, an alarm circuit, a power supply module, and a wireless communication module. The voltage transformer is connected to the signal conditioning circuit, the signal conditioning circuit is connected to the main processor, the alarm circuit is connected to the main processor, the wireless communication module is connected to the main processor, and the power supply module is connected to the main processor. The power supply module supplies power to the alarm. The voltage transformer collects the voltage and transmits it to the main processor. When a short-circuit fault occurs, the main processor transmits the alarm signal to the remote control terminal through the wireless transmission module or sends it to the operation and maintenance personnel in the form of a text message to timely remind the operation and maintenance personnel to make a treatment.

[0008] Further, the alarm system further includes a housing. The circuit board is arranged inside the housing. An alarm indicator light, a buzzer, and a power indicator light are arranged on the housing. Both the alarm indicator light and the buzzer are connected to the alarm circuit, and the power indicator light is connected to the power supply module. When the alarm system works, the power indicator light is on. When a short-circuit fault occurs, the alarm indicator light of the alarm is on and the buzzer sounds, which is convenient for the operation and maintenance personnel to quickly find the fault point, shorten the maintenance time, and reduce the economic loss.

[0009] Further, the system further includes a first fuse Fu1 and a second fuse Fu2. One end of the first fuse Fu1 is connected to one end of the through bolt, and the other end of the first fuse Fu1 is connected to one end of a first voltmeter V1 and one end of a second voltmeter V2. One end of the second fuse Fu2 is connected to the other end of the through bolt, and the other end of the second fuse Fu2 is connected to the other end of the second voltmeter V2. When the current in the system loop exceeds a certain limit for a period of time, the fuse melts, so as to disconnect the circuit and protect the circuit.

[0010] Further, the internal resistances of the first voltmeter V1 and the second voltmeter V2 are greater than or equal to 10 MΩ. Since the internal resistance of the voltmeter is large, the influence of the external circuit is low, and the voltages between the upper end of the through bolt and the ground and between the upper end and the lower end of the through bolt can be measured more accurately.

[0011] Further, the protection thresholds of the first fuse Fu1 and the second fuse Fu2 are both 0.5 A. When the current exceeds 0.5 A for a period of time, the fuse melts due to the heat generated by itself, so as to disconnect the circuit and protect the circuit.

[0012] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0013] 1. In the present invention, by arranging an alarm system between the through bolt and the positioning rib, when a short-circuit fault occurs in the through bolt, the alarm indicator light is on and the buzzer sounds, and timely and fast text message alarm is realized through the wireless communication module to remind the operation and maintenance personnel to make a treatment and shorten the maintenance time.

[0014] 2. In the present utility model, by directly connecting the two ends of the through bolt, the online acquisition of voltage data on the through bolt is realized.

[0015] 3. In the present utility model, the internal resistances of the first voltmeter V1 and the second voltmeter V2 are greater than or equal to 10 MΩ. The voltmeter with a large internal resistance is less affected by the external circuit and can more accurately measure the voltage of the upper end of the through bolt to the ground and the voltage of the upper end of the through bolt to the lower end.

[0016] 4. In the present utility model, the protection thresholds of the first fuse Fu1 and the second fuse Fu2 are 0.5 A. After the current exceeds 0.5 A for a period of time, the melt is melted by the heat generated by itself, so that the circuit is disconnected to protect the circuit, and serious damage to the system caused by internal faults can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the embodiments of the present utility model, and constitute a part of the present utility model, but do not limit the embodiments of the present utility model;

[0018] Figure 1 is the specific structural schematic diagram of the alarm in the present utility model;

[0019] Figure 2 is the schematic diagram of the alarm circuit in the present utility model;

[0020] Figure 3 is the schematic diagram of the system circuit in the present utility model;

[0021] Figure 4 is the equivalent circuit diagram of the through bolt when there is no fault in the present utility model;

[0022] Figure 5 is the equivalent circuit diagram of the through bolt when there is a single-point ground fault in the present utility model;

[0023] Figure 6 is the equivalent circuit diagram of the through bolt when there is a two-point ground fault in the present utility model;

[0024] Figure 7 is the simplified equivalent circuit diagram of the through bolt when there is a two-point ground fault in the present utility model;

[0025] Among them, 1 - pin one, 2 - pin two, 3 - pin three, 4 - pin four, 5 - pin five, 6 - pin six, 7 - pin seven, 8 - buzzer, 9 - alarm indicator light. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to more clearly understand the above-mentioned objects, features and advantages of the present utility model, the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present utility model and the features in the embodiments can be combined with each other.

[0027] In the following description, many specific details are set forth in order to fully understand the present utility model. However, the present utility model can also be implemented in other ways different from those described within the scope hereof. Therefore, the protection scope of the present utility model is not limited by the specific embodiments disclosed below.

[0028] Embodiment 1

[0029] Reference Figure 1 , this embodiment provides a monitoring system for the short-circuit fault of the stator through bolts and positioning ribs of a hydro-generator. The system includes an alarm system, and the alarm system includes a circuit board. The circuit board includes a main processor, a voltage transformer, a signal conditioning circuit, an alarm circuit, a power supply module and a wireless communication module. The voltage transformer is connected to the signal conditioning circuit, and the signal conditioning circuit is connected to the main processor; the alarm circuit is connected to the main processor; the wireless communication module is connected to the main processor; the power supply module is connected to the main processor.

[0030] The alarm system further includes a housing. The circuit board is arranged in the housing. An alarm indicator light 9, a buzzer 8 and a power indicator light are arranged on the housing. The alarm indicator light 9 and the buzzer 8 are both connected to the alarm circuit, and the power indicator light is connected to the power supply module.

[0031] Among them, the power supply module supplies power to the alarm. The voltage transformer collects the voltage and transmits it to the main processor. When a short-circuit fault occurs, the main processor transmits the alarm signal to the remote control terminal through the wireless transmission module or sends it to the operation and maintenance personnel in the form of a text message. At the same time, the alarm indicator light 9 of the alarm goes on and the buzzer 8 sounds, which is convenient for the operation and maintenance personnel to quickly find the fault point, shorten the maintenance time and reduce the economic loss.

[0032] Embodiment 2

[0033] Reference Figure 2, on the basis of Embodiment 1, in this embodiment, the alarm circuit includes an integrated circuit IC1, a resistor R8, a triode VT1, and a triode VT2. The integrated circuit IC1 is provided with seven pins, namely pin 1, pin 2, pin 3, pin 4, pin 5, pin 6, and pin 7. The base of the triode VT1 is connected to the output end of the main processor. The collector of the triode VT1 and pin 3 of the integrated circuit IC1 are both connected to the voltage source. The emitter of the triode VT1 is connected to pin 2 of the integrated circuit IC1. The two ends of the resistor R8 are respectively connected to pin 4 and pin 5 of the integrated circuit IC1. Pin 7 of the integrated circuit IC1 is connected to the base of the triode VT2. The emitter of the triode VT2, pin 1 and pin 6 of the integrated circuit IC1 are all grounded. The collector of the triode VT2 is connected to the alarm indicator 9. The alarm indicator 9 is connected to the buzzer 8, and the buzzer 8 is connected to the voltage source.

[0034] Among them, when a short - circuit fault occurs, the main processor outputs a high level. The triode VT1 obtains an appropriate bias current and conducts. The integrated circuit IC1 gets the working voltage, and the alarm circuit works. The alarm indicator 9 lights up, and the buzzer 8 sounds. The wireless communication module is a GPRS module, and the GPRS module is connected with a SIM - card interface module to achieve timely and rapid SMS alarm. Embodiment 3

[0035] Reference Figure 3 , this embodiment provides a monitoring system for the short - circuit fault of the stator through - bolt - locating rib of a hydro - generator. The system includes a measurement unit. The measurement unit includes a first voltmeter V1 and a second voltmeter V2. One end of the first voltmeter V1 is connected to one end of the through - bolt, and the other end of the first voltmeter V1 is grounded. The two ends of the second voltmeter V2 are respectively connected to both ends of the through - bolt. The first voltmeter V1 can measure the voltage U1 of the upper end of the through - bolt to the ground, and the second voltmeter V2 can measure the voltage U2 of the upper end of the through - bolt to the lower end. By directly connecting the two ends of the through - bolt, the on - line acquisition of voltage data on the through - bolt is realized.

[0036] Among them, the internal resistances of the first voltmeter V1 and the second voltmeter V2 are greater than or equal to 10 MΩ. The large internal resistance of the voltmeter has a low influence on the external circuit and can measure the voltage U1 of the upper end of the through - bolt to the ground and the voltage U2 of the upper end of the through - bolt to the lower end more accurately.

[0037] Among them, the instantaneous voltage values collected by this system can be applied to the short - circuit fault of the stator through - bolt - locating rib of the hydro - generator.

[0038] Embodiment 4

[0039] Reference Figure 3, on the basis of Embodiment 3, in this embodiment, the system further includes a first fuse Fu1 and a second fuse Fu2. One end of the first fuse Fu1 is connected to one end of the through bolt. The other end of the first fuse Fu1 is connected to one end of a first voltmeter V1 and one end of a second voltmeter V2. One end of the second fuse Fu2 is connected to the other end of the through bolt. The other end of the second fuse Fu2 is connected to the other end of the second voltmeter V2. The fuse melts the fuse wire after a certain period of time when the current in the system circuit exceeds a certain limit, thereby disconnecting the circuit to protect the circuit.

[0040] The protection thresholds of the first fuse Fu1 and the second fuse Fu2 are 0.5A. When the current exceeds 0.5A for a certain period of time, the fuse wire melts due to the heat generated by itself, disconnecting the circuit to protect the circuit, which can avoid serious damage to the system caused by internal faults.

[0041] Embodiment 5

[0042] Reference Figure 4 、 Figure 5 and Figure 6 , in this embodiment, the induced voltage generated by the through bolt in the magnetic field can be regarded as the voltage of a series circuit in which multiple power sources and resistors are connected in series. For example, it can be regarded as the circuit voltage of a first resistor R1, a first power source E1, a second resistor R2, a second power source E2, a third resistor R3, and a third power source E3 connected in series in sequence. The series structure of the power sources in this equivalent circuit can help determine the type of grounding fault.

[0043] Among them, when the grounding fault type of the through bolt is single-point grounding, the equivalent circuit further includes a first grounding resistor R4.

[0044] Among them, when the grounding fault type of the through bolt is two-point grounding, the equivalent circuit further includes a second grounding resistor R5 and a third grounding resistor R6.

[0045] In this embodiment, the position of the grounding resistor in the equivalent circuit is related to the position of the grounding point when the grounding fault occurs.

[0046] Embodiment 6

[0047] Reference Figure 4 、 Figure 5 and Figure 6, based on the above embodiments, this embodiment provides a method for judging the short-circuit fault type of a water turbine generator stator through-bolt-positioning rib short-circuit fault monitoring system. In practical applications, other fault judgment methods can be used for judgment, and the embodiments of the present invention do not make specific limitations. The present invention protects the monitoring system and does not protect the subsequent fault judgment methods. Those skilled in the art can select one or several fault judgment methods for implementation according to actual needs, and the embodiments of the present invention do not make specific limitations. The fault judgment method provided in this embodiment is as follows:

[0048] The system includes a measurement unit, a first fuse Fu1, and a second fuse Fu2. The measurement unit includes a first voltmeter V1 and a second voltmeter V2. The first voltmeter V1 measures the voltage U1 of one end of the through-bolt to the ground, and the second voltmeter V2 measures the voltage U2 between the two ends of the through-bolt. When both the voltage U1 of one end of the through-bolt to the ground and the voltage U2 from the upper end to the lower end of the through-bolt are constant, it is determined that the insulation of the through-bolt is good. Compare U1 with the single-point grounding fault threshold Y1. When the voltage U1 of one end of the through-bolt to the ground exceeds the single-point grounding fault threshold Y1, it is determined that the through-bolt has a single-point grounding fault. When comparing the voltage U2 from the upper end to the lower end of the through-bolt with the two-point grounding fault threshold Y2, when the voltage U2 from the upper end to the lower end of the through-bolt is lower than the two-point grounding fault threshold Y2, the through-bolt has a two-point or more grounding fault.

[0049] Among them, the single-point grounding fault threshold Y1 is taken as 0.45 - 0.55 times the induced voltage E value of the through-bolt, and the two-point grounding fault threshold Y2 is taken as 0.95 times the induced voltage E value of the through-bolt. The calculation formula for the induced voltage E of the through-bolt is:

[0050] E = UL2 / NL1;

[0051] Where U is the rated phase voltage of the generator, N is the number of series-connected stator bars in a single-phase winding, L1 is the width of the stator core yoke, and L2 is the distance between the through-bolt and the positioning rib at the bottom of the yoke.

[0052] Embodiment Seven

[0053] Reference Figure 5, this embodiment provides a method for judging the location of the grounding point when a single-point grounding fault occurs in the through-bolt. In practical applications, other methods for judging the location of the grounding point can be used for judgment. The embodiments of the present invention do not make specific limitations. What the present invention protects is the monitoring system and does not protect the subsequent methods for judging the location of the grounding point. Those skilled in the art can select one or several methods for judging the location of the grounding point according to actual needs for implementation. The embodiments of the present invention do not make specific limitations. The method for judging the location of the grounding point when a single-point grounding fault occurs provided in this embodiment is as follows:

[0054] When a single-point grounding fault occurs in the through-bolt, since the potential of the grounding point of the single-point grounding fault is 0 and no current loop is generated, the voltage U2 from the upper end to the lower end of the through-bolt remains unchanged. At this time, U1 = E1. Also, since the induced voltage and resistance value generated by each section of the through-bolt are proportional to the length of the through-bolt, the distance between the grounding point and the upper end of the iron core can be calculated by the ratio of the voltage U1 of one end of the through-bolt to the ground and the voltage U2 from the upper end to the lower end of the through-bolt. The calculation formula for the distance between the grounding point and the upper end of the iron core is:

[0055] L = h * U1 / U2;

[0056] Where h is the height of the stator iron core, U1 is the voltage of one end of the through-bolt measured by the first voltmeter V1 to the ground, U2 is the voltage between the two ends of the through-bolt measured by the second voltmeter V2, and L is the distance between the grounding point and the upper end of the iron core.

[0057] Embodiment Eight

[0058] Reference Figure 6 and Figure 7 , this embodiment provides a pre-judgment method, which can pre-judge the accident of burning damage of the generator stator iron core caused by a two-point grounding fault occurring at both ends of the second resistor and the second power supply. In practical applications, other pre-judgment methods can be used for pre-judgment. The embodiments of the present invention do not make specific limitations. What the present invention protects is the monitoring system and does not protect the subsequent pre-judgment methods. Those skilled in the art can select one or several pre-judgment methods according to actual needs for implementation. The embodiments of the present invention do not make specific limitations. The pre-judgment method provided in this embodiment is as follows:

[0059] When the two points of the through bolt are grounded through two resistors, namely the second grounding resistor R5 and the third grounding resistor R6, the circuit current can be simplified. After simplification, the resistor R7 is the equivalent resistor of the second grounding resistor R5 and R6. When a two-point grounding fault occurs at both ends of the second power supply, the smaller the voltage U2 between the two ends of the through bolt, the larger the induced current I, and the more easily the generator stator core is burned out. Therefore, by observing the magnitude of the voltage U2 at the upper end of the through bolt relative to the lower end, it is possible to predict the generator stator core burnout accident caused by the two-point grounding fault at the second resistor and both ends of the second power supply. The calculation formula for the voltage U2 between the two ends of the through bolt is as follows:

[0060] R7 = R5 + R6;

[0061] I = E2 / (R2 + R7);

[0062] U R7 = E2 * R7 / (R2 + R7);

[0063] U2 = E1 + E3 + U R7 ;

[0064] Wherein, R5 and R6 are respectively the resistance values of the grounding resistors at the two points at this time, R7 is the equivalent resistance value of the second grounding resistor R5 and the third grounding resistor R6, I is the induced current of the equivalent circuit, E1, E2, and E3 are respectively the electromotive forces of the first power supply E1, the second power supply E2, and the third power supply E3, U R7 is the voltage across the equivalent resistor R7, and U2 is the voltage between the two ends of the through bolt.

[0065] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0066] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A short - circuit fault monitoring system for the stator through - bolt - locating rib of a hydro - generator, characterized in that, It includes a measuring unit and an alarm system, and the alarm system is arranged between the through bolt and the positioning rib; the measuring unit includes a first voltmeter V1, one end of the first voltmeter V1 is connected to one end of the through bolt, the other end of the first voltmeter V1 is grounded, and both ends of the second voltmeter V2 are respectively connected to both ends of the through bolt.

2. The short - circuit fault monitoring system for the stator through - bolt - positioning rib of a hydro - generator according to claim 1, wherein, The alarm system includes a circuit board, and the circuit board includes a main processor, a voltage transformer, a signal conditioning circuit, an alarm circuit, a power supply module and a wireless communication module. The voltage transformer is connected to the signal conditioning circuit, and the signal conditioning circuit is connected to the main processor; the alarm circuit is connected to the main processor; the wireless communication module is connected to the main processor; the power supply module is connected to the main processor.

3. The short - circuit fault monitoring system for the stator through - bolt - locating rib of a hydro - generator according to claim 2, characterized in that, The alarm system further includes a housing, the circuit board is arranged in the housing, and an alarm indicator light (9), a buzzer (8) and a power indicator light are arranged on the housing. The alarm indicator light (9) and the buzzer (8) are both connected to the alarm circuit, and the power indicator light is connected to the power supply module.

4. A short - circuit fault monitoring system for the stator through - bolt - locating rib of a hydro - generator, according to claim 1, characterized in that, The system further includes a first fuse Fu1 and a second fuse Fu2. One end of the first fuse Fu1 is connected to one end of the through bolt, and the other end of the first fuse Fu1 is connected to one end of the first voltmeter V1 and one end of the second voltmeter V2. One end of the second fuse Fu2 is connected to the other end of the through bolt, and the other end of the second fuse Fu2 is connected to the other end of the second voltmeter V2.

5. A short - circuit fault monitoring system for the stator through - bolt - locating rib of a hydro - generator, as claimed in claim 1, wherein, The internal resistances of the first voltmeter V1 and the second voltmeter V2 are greater than or equal to 10 MΩ.

6. A monitoring system for short - circuit faults of the stator through - bolt - positioning rib of a hydro - generator, as claimed in claim 4, wherein, The protection thresholds of the first fuse Fu1 and the second fuse Fu2 are both 0.5 A.

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