Generator rotor winding temperature on-line monitoring and automatic calibration device

Abstract

The utility model discloses a generator rotor winding temperature on-line monitoring and automatic calibration device, and belongs to a generator rotor temperature monitoring device. The utility model aims to provide a generator rotor temperature monitoring device with high measurement precision. Comprising a voltage divider (3) which is connected in an excitation loop and is connected with a temperature measurement control unit (10) through a voltage transmitter (17), and a shunt (15) which is connected in the excitation loop and is connected with the temperature measurement control unit (10) through a current transmitter (13). A first isolation switch (5) controlled by an intelligent diagnosis module (16) is connected between the voltage transmitter (17) and the temperature measurement control unit (10), and a fourth isolation switch (12) controlled by the intelligent diagnosis module (16) is connected between the current transmitter (13) and the temperature measurement control unit (10). The intelligent diagnosis module (16) is connected with the temperature measurement control unit (10) through the second isolation switch (6) and the third isolation switch (11).

Description

Technical Field

[0001] The utility model relates to an online temperature monitoring device for a generator rotor winding, in particular to an online temperature monitoring device for a generator rotor winding with an automatic calibration function. Background Art

[0002] The temperature of the generator rotor winding is crucial to the safe and stable operation of the generator. At present, a temperature monitoring device is usually used to monitor the temperature of the generator rotor winding online. The online monitoring device is mainly composed of a DC excitation power supply that forms an excitation circuit by connecting the carbon brush group with the rotor slip ring, and a voltage divider and a current divider connected to the excitation circuit. Its working principle is: the DC voltage at both ends of the rotor winding is collected in real time by the voltage divider, and the DC current of the rotor winding is collected in real time by the current divider, and then the rotor winding resistance is calculated, and then the rotor winding temperature is obtained according to the resistance-temperature relationship curve. This method is relatively simple and easy to implement, but there are the following problems: for the convenience of measurement, the voltage collection point is mostly taken from the excitation power supply side. Since the rotor winding resistance is very small (generally only tens of milliohms), the resistance of the rotor winding external circuit, the resistance of the carbon brush group itself, and the contact resistance between the carbon brush group and the slip ring will have a greater impact on the rotor winding temperature, resulting in poor measurement accuracy.

[0003] In order to eliminate the influence of the external circuit resistance of the rotor winding on the temperature measurement and improve the measurement accuracy, the applicant disclosed a utility model patent named "Online Monitoring Device for Generator Rotor Winding Temperature (CN 204027718 U)". Although the utility model patent changes the voltage collection point originally set on the self-excitation power supply side to the carbon brush group or auxiliary carbon brush, and adds voltage transmitters and current transmitters, it can eliminate the influence of the external circuit resistance of the rotor winding on the temperature measurement and improve the measurement accuracy. However, there are the following defects: after the online monitoring device has been running for a period of time, it is impossible to perform intelligent diagnosis such as pattern recognition, fault analysis, fuzzy calculation, etc., resulting in reduced measurement accuracy; it is urgently needed to be improved. Utility Model Content

[0004] In view of the above-mentioned defects in the prior art, the utility model aims to provide a generator rotor winding temperature online monitoring and automatic calibration device with an automatic calibration function.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following scheme: it includes a voltage divider connected in the excitation circuit and connected to the temperature measurement control unit through a voltage transmitter, and a shunt connected in the excitation circuit and connected to the temperature measurement control unit through a current transmitter; a first isolating switch controlled by an intelligent diagnosis module is connected to the circuit between the voltage transmitter and the temperature measurement control unit, and a fourth isolating switch controlled by the intelligent diagnosis module is connected to the circuit between the current transmitter and the temperature measurement control unit; the intelligent diagnosis module is connected to the temperature measurement control unit through the second isolating switch and the third isolating switch respectively.

[0006] The intelligent diagnosis module is composed of a DC voltage output circuit and a DC current output circuit connected to a control processing unit.

[0007] The temperature measurement control unit is connected with the display, the alarm and the communication interface respectively.

[0008] Compared with the prior art, the utility model adopts the above technical solution. On the one hand, the DC voltage output circuit and the DC current output circuit in the intelligent diagnosis module are respectively connected to the temperature measurement control unit through the isolation switch, so the circuit between the DC voltage output circuit, the DC current output circuit and the temperature measurement control unit can be switched, and the temperature measurement control unit can be automatically calibrated. On the other hand, since the isolation switch controlled by the intelligent diagnosis module is added between the voltage transmitter and the temperature measurement control unit and between the current transmitter and the temperature measurement control unit, the circuit between the voltage transmitter, the current transmitter and the temperature measurement control unit can be switched by using the intelligent diagnosis module, so as to realize the rotor winding temperature detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the principle of an embodiment of the utility model;

[0010] Figure 2 It is a schematic diagram of the principle of another embodiment of the utility model;

[0011] Figure 3 It is a schematic diagram of the principle of the intelligent diagnosis module in the utility model.

[0012] In the figure: carbon brush group 1, slip ring 2, voltage divider 3, rotor winding 4, first isolating switch 5, second isolating switch 6, display 7, alarm 8, communication interface 9, temperature measurement control unit 10, third isolating switch 11, fourth isolating switch 12, current transmitter 13, DC excitation power supply 14, shunt 15, intelligent diagnosis module 16, control processing unit 16-1, DC voltage output circuit 16-2, DC current output circuit 16-3, voltage transmitter 17, auxiliary carbon brush 18. DETAILED DESCRIPTION

[0013] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments. Example

[0014] like Figure 1 , Figure 3 As shown: slip rings 2 are connected to both ends of the rotor winding 4, and carbon brush groups 1 are connected to both ends of the DC excitation power supply 14. The two carbon brush groups 1 are connected to the two slip rings 2 so that the DC excitation power supply 14 and the rotor winding 4 form an excitation circuit. The voltage divider 3 connected between the two carbon brush groups 1 is connected to the temperature measurement control unit 10 through the voltage transmitter 17 and the first isolating switch 5 in sequence, and the shunt 15 connected between the carbon brush group 1 and the DC excitation power supply 14 is connected to the temperature measurement control unit 10 through the current transmitter 13 and the fourth isolating switch 12 in sequence; the first isolating switch 5 and the fourth isolating switch 12 are respectively controlled by the intelligent diagnosis module 1. The intelligent diagnosis module 16 is composed of a DC voltage output circuit 16-2 and a DC current output circuit 16-3 connected to the control processing unit 16-1; the DC voltage output circuit 16-2 is connected to the temperature measurement control unit 10 through the second isolating switch 6, and the DC current output circuit 16-3 is connected to the temperature measurement control unit 10 through the third isolating switch 11. The first isolating switch 5 , the second isolating switch 6 , the third isolating switch 11 , and the fourth isolating switch 12 are all connected to the control processing unit 16 - 1 , respectively. Example

[0015] In order to prevent the resistance of the carbon brush set 1 itself and the contact resistance between the carbon brush set 1 and the slip ring 2 from affecting the temperature detection of the rotor winding 4, the present invention can also adopt the following method based on the embodiment 1: Figure 2 The technical solution shown is as follows: an auxiliary carbon brush 18 is added to each of the two slip rings 2 , and the auxiliary carbon brush 18 on each slip ring 2 is electrically isolated from the carbon brush group 1 on the slip ring; and the voltage divider 3 is directly connected between the two auxiliary carbon brushes 18 .

[0016] In order to realize the alarm prompt, the utility model can also adopt the following structure on the basis of the above two embodiments: the temperature measurement control unit 10 is respectively connected to the display 7 and the alarm 8; in order to realize remote monitoring, the temperature measurement control unit 10 is connected to the communication interface 9 of the remote monitoring device (see Figures 1-2 ).

[0017] from Figures 1-2It can be seen that: for the convenience of detection, the traditional temperature measuring device usually selects the voltage collection point on the side close to the DC excitation power supply 14 (i.e., points a and b). Therefore, the resistance of the external circuit of the rotor winding 4, the resistance of the carbon brush group 1 itself, and the contact resistance between the carbon brush group 1 and the slip ring 2 can have a great influence on the resistance temperature of the rotor winding 4, and the measurement accuracy is not high. However, the utility model directly takes the voltage collection point from the carbon brush group 1 (i.e., points c and d), or from the auxiliary carbon brush 18 fixed on the slip ring 2 (i.e., points e and f); therefore, the resistance of the external circuit of the rotor winding 4 (i.e., the resistance of the ac segment and the bd segment), the resistance of the carbon brush group 1 itself, and the contact resistance between the carbon brush group 1 and the slip ring 2 on the resistance temperature of the rotor winding 4 can be eliminated, thereby improving the measurement accuracy.

[0018] Working principle:

[0019] like Figure 3 As shown, the control processing unit 16-1 first controls the first isolating switch 5 and the fourth isolating switch 12 to be disconnected, and controls the second isolating switch 6 and the third isolating switch 11 to be closed. At this time, the intelligent diagnosis module 16 is in the automatic calibration mode: the DC voltage output circuit 16-2 outputs a constant DC voltage signal to the temperature measurement control unit 10, and the DC current output circuit 16-3 outputs a constant DC current signal to the temperature measurement control unit 10. The temperature measurement control unit 10 performs diagnostic analysis based on the current operation mode and the received data, and automatically calibrates the operation parameters. Therefore, the influence of long-term operation and changes in the operating environment on temperature measurement can be eliminated, the automation of detection data diagnosis can be realized, and the detection accuracy and stability can be improved.

[0020] After the calibration is completed, the control processing unit 16-1 controls the first isolating switch 5 and the fourth isolating switch 12 to close, and controls the second isolating switch 6 and the third isolating switch 11 to open. At this time, the intelligent diagnosis module 16 switches to the automatic monitoring mode: the voltage transmitter 17 transmits the collected rotor winding voltage signal to the temperature measurement control unit 10, and the current transmitter 13 transmits the collected rotor winding current signal to the temperature measurement control unit 10. The temperature measurement control unit 10 calculates the resistance of the rotor winding 4 and the rotor winding temperature corresponding to the resistance, and prompts through the display 7, alarm 8, communication interface 9, etc.

Claims

1. A device for online monitoring and automatic calibration of the temperature of a generator rotor winding, comprising a voltage divider (3) connected in an excitation circuit and connected to a temperature measurement control unit (10) via a voltage transmitter (17), and a current divider (15) connected in the excitation circuit and connected to the temperature measurement control unit (10) via a current transmitter (13); characterized in that: A first isolating switch (5) controlled by an intelligent diagnosis module (16) is connected to the circuit between the voltage transmitter (17) and the temperature measurement control unit (10); a fourth isolating switch (12) controlled by the intelligent diagnosis module (16) is connected to the circuit between the current transmitter (13) and the temperature measurement control unit (10); the intelligent diagnosis module (16) is connected to the temperature measurement control unit (10) via the second isolating switch (6) and the third isolating switch (11), respectively.

2. The generator rotor winding temperature online monitoring and automatic calibration device according to claim 1 is characterized in that: The intelligent diagnosis module (16) is composed of a DC voltage output circuit (16-2) and a DC current output circuit (16-3) connected to a control processing unit (16-1).

3. The generator rotor winding temperature online monitoring and automatic calibration device according to claim 2 is characterized in that: The temperature measurement control unit (10) is connected to the display (7), the alarm (8), and the communication interface (9) respectively.

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