Large generator excitation DC power cable state monitoring device

Abstract

The utility model discloses a large-scale generator excitation direct current power cable state monitoring device, which detects temperature, humidity and combustible gas concentration environmental data of positions such as cable holes, cable shafts and the like which are easy to heat or inconvenient to inspect through measuring elements. And current data and insulation data of the excitation direct-current power cable are acquired at a joint of an excitation system or a generator collector ring, analysis and judgment are performed through an excitation direct-current power cable fault diagnosis mechanism, and a judgment result is sent to a monitoring picture of operation and maintenance personnel. During specific judgment, if all sampling data values are within a standard range fixed value set in the excitation direct-current power cable fault diagnosis mechanism, the running state of the excitation direct-current power cable is determined to be normal, and otherwise, the running state of the excitation direct-current power cable is determined to be abnormal. The device is low in power, strong in anti-interference, accurate in measured value, and suitable for monitoring the operating environment state of the excitation direct-current power cable.

Description

Technical Field

[0001] The utility model belongs to the technical field of equipment monitoring and relates to a state monitoring device for a large-scale generator excitation DC power cable. Background Art

[0002] The generator excitation system is responsible for providing DC excitation current for the generator rotor, which is input into the generator rotor excitation winding through the excitation DC power cable, slip rings and carbon brushes. Generally, the rated excitation current of a large generator set can reach more than 2000A, and the excitation DC power cable is usually composed of 10 positive and 10 negative flame-retardant cables or more. The excitation DC power cable is often affected by factors such as ambient temperature, humidity, cable overload, etc., resulting in a decrease in insulation performance or mechanical properties, oil precipitation on the cable surface, and a decrease in the actual life of the cable. In extreme cases, the cable temperature will be too high and it will spontaneously ignite. How to judge the deterioration trend of the excitation DC power cable during the fault latency period, replace the faulty cable in advance or take necessary emergency measures to ensure the safe and stable operation of the generator set has become a hot topic.

[0003] At present, the operation status of excitation DC power cables in power plants is generally monitored by operation and maintenance personnel using infrared thermometers or infrared thermal imagers, and the temperature of key parts is recorded, and then manual data analysis is performed. In addition, the insulation resistance measurement of excitation DC power cables can only be carried out when the power is off during maintenance. There is a lack of daily monitoring of the insulation strength of excitation DC power cables during long-term operation. In addition, due to the limited cable laying path, the laying lengths of each excitation DC power cable cannot be completely consistent, and the current distribution of each cable is uneven, which will cause the temperature of some carbon brushes to rise, resulting in serious consequences such as carbon brush ignition and collector ring burns. Utility Model Content

[0004] The utility model aims to provide a large generator excitation DC power cable state monitoring device, aiming to solve the problems of cable insulation and mechanical performance degradation, cable life reduction, carbon brush sparking, and collector ring burns caused by factors such as operating environment temperature, humidity, cable overload, and unbalanced cable current carrying capacity of the excitation DC power cable.

[0005] To achieve the above purpose, the utility model is implemented through the following technical solutions:

[0006] The utility model is a large generator excitation DC power cable state monitoring device, comprising: a data acquisition mechanism, a data processor, an excitation DC power cable fault diagnosis mechanism, a monitoring mechanism and a communication mechanism; wherein:

[0007] The data acquisition mechanism includes a current measuring element, an insulation strength measuring element, a temperature measuring element, a smoke measuring element, a humidity measuring element, a power supply element, a first communication element and a shell; the temperature measuring element, the smoke measuring element and the humidity measuring element are arranged at a preset monitoring position of the excitation DC power cable to be tested, so as to measure the temperature, humidity and combustible gas concentration environmental data of the DC cable; the current measuring element and the insulation strength measuring element are arranged at the joint of the excitation system of the excitation DC power cable to be tested or the collector ring of the generator, so as to collect the current data and insulation data of the excitation DC power cable; the power supply element is connected to the power-consuming element in the data acquisition mechanism to supply power; the signal receiving end of the current measuring element, the insulation strength measuring element, the temperature measuring element, the smoke measuring element and the humidity measuring element is integrated with the power supply element and the first communication element and arranged in the shell;

[0008] The data processor includes a plate housing, an input-output conversion element, and a second communication element. The input end of the input-output conversion element is connected to the first communication element to receive the relevant operation data of the excitation DC power cable to be tested collected by the data collection mechanism and send it to the second communication element in the data processor;

[0009] The excitation DC power cable fault diagnosis mechanism adopts the NS32F407ZGT6 chip. The second communication element is connected to the excitation DC power cable fault diagnosis mechanism. The excitation DC power cable fault diagnosis mechanism receives the relevant operating data of the excitation DC power cable to be tested for analysis and judgment, and sends the judgment result to the monitoring mechanism of the operation and maintenance personnel through the communication mechanism.

[0010] As a preferred technical solution, the communication interface of the communication mechanism adopts an RS485 interface, the communication protocol adopts Modbus-RTU, and the protection level is TVS protection.

[0011] As a preferred technical solution, the shell is made of an anti-interference metal shielding shell, and the panel shell has a dustproof function.

[0012] As a preferred technical solution, the preset monitoring position of the excitation DC power cable (6) to be tested is a position that is easy to heat or inconvenient to inspect, passing through a cable hole or a cable shaft.

[0013] Different from the prior art, the large generator excitation DC power cable status monitoring device provided by the utility model detects the temperature, humidity, and combustible gas concentration environmental data of cable holes, cable shafts and other locations that are prone to heat or inconvenient for inspection through measuring elements, as well as the current data and insulation data of the excitation DC power cable at the joints of the excitation system or the generator collector ring, and analyzes and judges through the excitation DC power cable fault diagnosis mechanism, and sends the judgment result to the monitoring screen of the operation and maintenance personnel. During the specific judgment, if all the sampled data values ​​are within the standard range set in the excitation DC power cable fault diagnosis mechanism, the operating status of the excitation DC power cable will be determined to be normal, otherwise it will be determined to be abnormal. This device has low power, strong anti-interference, and accurate measurement values, and is suitable for monitoring the operating environment status of the excitation DC power cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The aspects and advantages of the present invention and / or additional aspects will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0015] Figure 1 The utility model provides a structural schematic diagram of a large generator excitation DC power cable state monitoring and evaluation device.

[0016] In the figure, 1. data acquisition mechanism; 11. current measuring element; 12. insulation strength measuring element; 13. temperature measuring element; 14. smoke measuring element; 15. humidity measuring element; 16. power supply element; 17. first communication element; 18. housing; 2. data processor; 21. board housing; 22. input-output conversion element; 22. second communication element; 3. excitation DC power cable fault diagnosis mechanism; 4. monitoring mechanism; 5. communication mechanism; 6. excitation DC power cable. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0018] Figure 1 The utility model provides a large generator excitation DC power cable state monitoring device, including a data acquisition mechanism 1, a data processor 2 and an excitation DC power cable fault diagnosis mechanism 3; wherein,

[0019] The data acquisition mechanism 1 comprises a current measuring element 11, an insulation strength measuring element 12, a temperature measuring element 13, a smoke measuring element 14, a humidity measuring element 15, a power supply mechanism 16, a first communication element 17 and a housing 18; the current measuring element 11, the insulation strength measuring element 12, the temperature measuring element 13, the smoke measuring element 14 and the humidity measuring element 15 are arranged at a preset monitoring position of the excitation DC power cable (6) to be tested, and are implemented by using existing sensors and measuring elements well known to those skilled in the art. Specifically, the temperature measuring element 13, the smoke measuring element 14 and the humidity measuring element 15 are arranged at a position where the excitation DC power cable 6 to be tested passes through a cable hole, a cable shaft or other position that is prone to heat or inconvenient for inspection, to measure the temperature, humidity and combustible gas concentration environmental data of the DC cable; the current measuring element 11 and the insulation strength measuring element 12 are installed at the joint of the excitation system or the generator collector ring of the excitation DC power cable 6 to be tested, and collect the current data and insulation data of the excitation DC power cable 6. The signal receiving end of the current measuring element 11, the insulation strength measuring element 12, the temperature measuring element 13, the smoke measuring element 14 and the humidity measuring element 15 is integrated with the power supply element 16 and the first communication element 17 in the housing (18). The current measuring element 11, the insulation strength measuring element 12, the temperature measuring element 13, the smoke measuring element 14 and the humidity measuring element 15 send all the collected signals to the first communication element 17. The power supply element 16 is connected to the electrical elements in the data collection mechanism 1 to supply power. At the same time, the power supply element 16 is connected to the data processor 2 arranged in the panel housing 18 to provide power.

[0020] The data processor 2 includes a panel housing 21, an input-output conversion element 22, and a second communication element 23. The input end of the input-output conversion element 22 is connected to the first communication element 17 to receive the relevant operating data of the excitation DC power cable 6 to be tested collected by the data acquisition mechanism 1, and send it to the second communication element 23 in the data processor 2; the input-output conversion element 22 is connected to the first communication element 17 to receive the relevant operating data of the excitation power cable collected by the data acquisition mechanism 1, thereby converting the physical quantity into a standard current signal of 4-20mA, and sending it to the second communication element 23 in the data processor 2.

[0021] The excitation DC power cable fault diagnosis mechanism 3 adopts the NS32F407ZGT6 chip, and the second communication element 23 is connected to the excitation DC power cable fault diagnosis mechanism 3. The excitation DC power cable fault diagnosis mechanism 3 receives the relevant operation data of the excitation DC power cable 6 to be tested, analyzes and judges, and sends the judgment result to the monitoring mechanism 4 of the operation and maintenance personnel through the communication mechanism 5.

[0022] In the present invention, the communication interface of the communication mechanism 5 adopts the RS485 interface, the communication protocol adopts Modbus-RTU, and the protection level is TVS protection.

[0023] The housing 18 is made of an anti-interference metal shielding shell, and the panel housing 21 has a dustproof function.

[0024] The excitation DC power cable fault diagnosis mechanism 3 is implemented by using the existing NS32F407ZGT6 chip. The specific structure and working principle of the NS32F407ZGT6 chip are existing technologies well known to those skilled in the art, and thus will not be described in detail here.

[0025] In addition, if Figure 1 As shown, the power supply element 16 includes a rectifier unit 161, a battery 162, a voltage stabilizing circuit 163, two DC outputs 164 and a photovoltaic module; wherein the output end of the voltage stabilizing circuit 163 is connected to the input-output conversion element 22. Thus, the utility model adopts photovoltaics and batteries to jointly power the input-output conversion element 22, thereby effectively solving the problem that underground cables cannot provide power for a long time. The photovoltaic modules and voltage stabilizing circuits of the photovoltaic power supply can be implemented using existing structures and circuits, which will not be described in detail here.

[0026] Different from the prior art, the large generator excitation DC power cable status monitoring device provided by the utility model detects the temperature, humidity, and combustible gas concentration environmental data of cable holes, cable shafts and other locations that are prone to heat or inconvenient for inspection through measuring elements, as well as the current data and insulation data of the excitation DC power cable at the joints of the excitation system or the generator collector ring, and analyzes and judges through the excitation DC power cable fault diagnosis mechanism, and sends the judgment result to the monitoring screen of the operation and maintenance personnel. During the specific judgment, if all the sampled data values ​​are within the standard range set in the excitation DC power cable fault diagnosis mechanism, the operating status of the excitation DC power cable will be determined to be normal, otherwise it will be determined to be abnormal. This device has low power, strong anti-interference, and accurate measurement values, and is suitable for monitoring the operating environment status of the excitation DC power cable.

[0027] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code including one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0030] Although the embodiments of the present invention have been shown and described above, it is to be understood that the embodiments are illustrative and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the embodiments within the scope of the present invention.

Claims

1. A large generator excitation DC power cable status monitoring device, characterized in that: It comprises a data acquisition mechanism (1), a data processor (2), an excitation DC power cable fault diagnosis mechanism (3), a monitoring mechanism (4) and a communication mechanism (5); wherein: The data acquisition mechanism (1) comprises a current measuring element (11), a dielectric strength measuring element (12), a temperature measuring element (13), a smoke measuring element (14), a humidity measuring element (15), a power supply element (16), a first communication element (17) and a housing (18); the temperature measuring element (13), the smoke measuring element (14) and the humidity measuring element (15) are arranged at a preset monitoring position of the excitation DC power cable (6) to be measured, and are used to measure the DC cable temperature, humidity and combustible gas concentration environmental data; the current measuring element (11), the dielectric strength measuring element (12), the smoke measuring element (14), and the humidity measuring element (15) are arranged at a preset monitoring position of the excitation DC power cable (6) to be measured, and are used to measure the DC cable temperature, humidity and combustible gas concentration environmental data; the The measuring element (12) is arranged at the joint of the excitation system of the excitation DC power cable (6) to be measured or the collector ring of the generator, and is used to collect current data and insulation data of the excitation DC power cable; the power supply element (16) is connected to the power-consuming element in the data acquisition mechanism (1) to supply power; the signal receiving ends of the current measuring element (11), the insulation strength measuring element (12), the temperature measuring element (13), the smoke measuring element (14) and the humidity measuring element (15) are integrated with the power supply element (16) and the first communication element (17) and are arranged in the housing (18); The data processor (2) comprises a plate housing (21), an input / output conversion element (22), and a second communication element (23); an input end of the input / output conversion element (22) is connected to the first communication element (17) to receive relevant operating data of the excitation DC power cable (6) to be tested collected by the data collection mechanism (1) and send the data to the second communication element (23) in the data processor (2); The excitation DC power cable fault diagnosis mechanism (3) uses an NS32F407ZGT6 chip, and the second communication element (23) is connected to the excitation DC power cable fault diagnosis mechanism (3). The excitation DC power cable fault diagnosis mechanism (3) receives relevant operating data of the excitation DC power cable (6) to be tested, analyzes and judges it, and sends the judgment result to the monitoring mechanism (4) of the operation and maintenance personnel through the communication mechanism (5).

2. The large generator excitation DC power cable state monitoring device according to claim 1 is characterized in that: The communication interface of the communication mechanism (5) adopts an RS485 interface, the communication protocol adopts Modbus-RTU, and the protection level is TVS protection.

3. The large generator excitation DC power cable state monitoring device according to claim 1 is characterized in that: The housing (18) is made of an anti-interference metal shielding shell, and the plate housing (21) has a dustproof function.

4. The large generator excitation DC power cable state monitoring device according to claim 1 is characterized in that: The preset monitoring position of the excitation DC power cable (6) to be tested is a position that is easy to generate heat or inconvenient to inspect, passing through a cable hole or a cable shaft.

Images