Shaft electric quantity monitoring and protecting device

Abstract

The utility model relates to a shaft electric quantity monitoring and protecting device. The shaft voltage, shaft current and shaft insulation parameters of the water-turbine generator set can be accurately monitored at the same time, an alarm signal is sent out in time when the parameters suddenly change and exceed the limit, safe operation of the set is guaranteed, and the system has high integration level, high reliability and a good communication function. According to the technical scheme of the utility model, the device comprises a shaft voltage measurement module, a shaft current measurement module, a shaft insulation measurement module, a display module, a communication module and an input and output module which are electrically connected with a PLC controller. The shaft voltage measuring module detects a shaft voltage signal through a shaft voltage carbon brush and a grounding carbon brush which are connected to two sides of a large shaft rotor of the generator set; the shaft current measuring module detects a shaft electric signal through a shaft current sensor arranged on a large shaft of the generator; the shaft insulation measurement module monitors a unit insulation layer copper foil and a large shaft through a shaft insulation front-end device; and the insulation resistance value between the insulation layer copper foil and the shaft collar.

Description

TECHNICAL FIELD

[0001] The utility model relates to water turbine generator set monitoring protection technical field, concretely relates to a kind of shaft electric quantity monitoring protection device. TECHNICAL BACKGROUND

[0002] Water turbine generator set is inevitably produced shaft voltage in the process of operation due to stator magnetic field imbalance and other reasons.When shaft voltage is too large or shafting insulation is damaged, shaft voltage can cause large shaft current. Due to the existence of shaft voltage and shaft current, the stability of bearing oil film can be damaged, and then the shaft neck surface and bushing can be burned, and even bearing damage can be caused in severe cases, which poses a great threat to the safe and stable operation of water turbine generator set.

[0003] At present, the existing monitoring device on the market cannot meet the requirements in terms of functional integration, measurement accuracy and alarm timeliness, and has the following problems:

[0004] 1. It cannot accurately monitor shaft voltage, shaft current and shaft insulation parameters at the same time;

[0005] 2. The adopted technical means is backward, cannot effectively analyze and process signals, and it is difficult to accurately obtain the real-time values of the effective value, fundamental wave and third harmonic component of the parameters;

[0006] 3. The communication function is poor, cannot be conveniently connected with the whole plant computer monitoring system, leading to that monitoring data cannot be timely uploaded and shared, and it is difficult to meet the demand of modern power station for real-time monitoring and protection of equipment. UTILITY MODEL CONTENT

[0007] Therefore, the utility model discloses a kind of shaft electric quantity monitoring protection device, which can accurately monitor the shaft voltage, shaft current and shaft insulation parameters of water turbine generator set at the same time, timely sends alarm signal when parameter mutation is out of limit, ensures the safe operation of unit, and has high integration, high reliability and good communication function.

[0008] To achieve the above object, the utility model adopts the technical scheme that a kind of shaft electric quantity monitoring protection device, including shaft voltage measurement module, shaft current measurement module, shaft insulation measurement module, PLC controller, display module, communication module and input-output module composition, the shaft voltage measurement module, shaft current measurement module, shaft insulation measurement module, display module, communication module and input-output module are electrically connected with PLC controller respectively;

[0009] The shaft voltage measurement module detects shaft voltage signal by connecting shaft voltage carbon brush and grounding carbon brush on both sides of generator set large shaft rotor;

[0010] The shaft current measurement module detects shaft electric signal by setting shaft current sensor on generator large shaft.

[0011] The shaft insulation measurement module monitors the insulation resistance value between the copper foil of the insulation layer of the unit and the large shaft and between the copper foil of the insulation layer and the shaft ring through the shaft insulation preprocessor.

[0012] Further, the display module displays the measurement values of the shaft voltage, the shaft current and the shaft insulation through the LED digital tube.

[0013] Further, the input and output module is used for receiving the signal of the PLC controller and outputting the shaft voltage, the shaft current and the shaft insulation three parameters, and can output two-stage alarm signals.

[0014] Further, the shaft current sensor is arranged around the large shaft of the generator.

[0015] Further, the model of the PLC controller is ST30.

[0016] Compared with the prior art, the utility model has the advantages of:

[0017] 1) The utility model has high integration degree, can monitor the shaft voltage, the shaft current and the shaft insulation parameters simultaneously, reduces the equipment quantity, reduces the cost, and improves the compactness of the system.

[0018] 2) The utility model adopts the advanced digital signal processing technology, the measurement precision is high, can accurately obtain the real-time value of the effective value, the fundamental wave and the third harmonic component of the shaft voltage and the shaft current, provides more accurate data for the unit operation state evaluation.

[0019] 3) The utility model is measured with the shaft insulation preprocessor and the rear end device, and the real-time performance is good, and the shaft insulation fault hidden danger can be found in time.

[0020] 4) The utility model controls adopts the high-performance PLC, guarantees the reliable operation of the device, the data processing speed is fast, and the alarm response is timely.

[0021] 5) The utility model has multiple display modes and good communication function, is convenient for on-site operation and remote monitoring management, and improves the safety and reliability of equipment operation. DETAILED DESCRIPTION

[0022] Figure 1 It is the structure diagram of the utility model.

[0023] Figure 2 It is the circuit diagram of the utility model.

[0024] Figure 3 It is the sensor installation schematic diagram.

[0025] Marking description: 1, shaft voltage carbon brush; 2, copper foil; 3, rotor; 4, insulation layer; 5, guide shoe; 6, shaft collar; 7, shaft current sensor; 8, large shaft; 9, grounding carbon brush; 10, shaft insulation preamplifier; 11, insulation layer copper foil carbon brush; 12, shaft collar carbon brush. DETAILED DESCRIPTION

[0026] In the description of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary skilled in the art without creative labor are within the scope of protection of the present application.

[0028] The present embodiment provides a kind of shaft electric quantity monitoring protection device, as shown in Figure Figure 1 It includes shaft voltage measurement module, shaft current measurement module, shaft insulation measurement module, high-performance PLC controller, display module (LED nixie tube and liquid crystal touch screen), communication module (RS485 interface, MODBUS RTU protocol is followed) and input-output module, above-mentioned shaft voltage measurement module, shaft current measurement module, shaft insulation measurement module, display module, communication module and input-output module are respectively electrically connected with PLC controller.

[0029] Shaft voltage measurement module: shaft voltage measurement uses the shaft voltage carbon brush 1 and the ground carbon brush 9 arranged on both sides of the rotor of the generator shaft 8, and the shaft voltage generated during the rotation of the shaft 8 is input into the measuring device through the two carbon brushes. The device first filters the signal inside. Because there are various electromagnetic interferences in the actual operating environment, filtering can effectively remove these interference signals to ensure the purity of the collected shaft voltage signal. After filtering, the signal is analyzed and calculated through advanced digital signal processing technology. This technology can separate components of different frequencies from complex voltage signals to obtain the real-time values of the effective value, fundamental wave (50Hz) and third harmonic (150Hz) components of the shaft voltage. Finally, the calculated effective value is sent to the PLC for subsequent calculation, judgment and processing, providing a basis for evaluating whether the shaft voltage is normal and whether an alarm signal needs to be sent.

[0030] Shaft current measurement module: a shaft current sensor 7 is used, and shaft current monitoring is achieved by surrounding the shaft current sensor 7 around the generator shaft 8. When there is current flowing through the shaft 8, according to the principle of electromagnetic induction, the shaft current sensor will convert the shaft current into an electromagnetic signal, and then output the corresponding current signal. After the current signal is input into the monitoring device, the device inside also needs to be filtered to remove interference components. The filtered shaft current signal is then calculated through a specific algorithm and processing circuit to obtain the fundamental wave and harmonic components of the shaft current. Similar to shaft voltage measurement, the effective value of the shaft current is also extracted and sent to the PLC. The PLC judges the shaft current effective value according to the preset alarm threshold. Once the shaft current exceeds the set alarm value, the corresponding alarm action will be triggered to prompt the staff that the unit may have an abnormality.

[0031] Shaft insulation measurement module: shaft insulation monitoring uses a shaft insulation preprocessor and a rear-end device (the structure of the utility model) to work together. The insulation mechanism of the generator rotor front side is usually set with a shaft ring 6 insulation layer or a guide shoe 5 insulation base. The shaft insulation preprocessor is responsible for real-time sampling of the insulation resistance value between the insulation layer copper foil 2 and the shaft 8, and the insulation layer copper foil 2 and the shaft ring 6 (or the guide shoe insulation base). (Note: The insulation layer copper foil, the shaft, and the shaft ring are connected to the shaft insulation preprocessor through carbon brushes 11, 9, and 12, respectively.) After the data obtained by sampling is calculated and processed inside the shaft insulation preprocessor, it is transmitted to the rear-end monitoring device (the structure of the utility model) through the RS485 bus. After receiving the data, the rear-end monitoring device further analyzes and processes it, judges the shaft insulation state according to the preset insulation performance standard and alarm threshold. If the shaft insulation measurement value is lower than the set alarm value, the rear-end monitoring device will make an alarm judgment and transmit the relevant information to the PLC, which will control the alarm signal to remind the staff to pay attention to the shaft insulation and take timely measures to prevent more serious faults caused by shaft insulation problems.

[0032] PLC controller: high-performance PLC is adopted, and the model thereof is ST30, which receives signals from shaft voltage, shaft current and shaft insulation measurement module, and performs comprehensive calculation processing, and according to preset alarm threshold, each parameter is judged in real time, and once the parameter exceeds the threshold, an alarm signal is triggered immediately, and relevant process values are forwarded.

[0033] Display module: shaft voltage, shaft current and shaft insulation measurement values are displayed through LED nixie tubes, so that field operators can quickly read data. Communication module: integrated RS485 communication interface, MODBUS RTU protocol is followed, data remote transmission and sharing can be realized by connecting with a whole plant computer monitoring system, and remote monitoring and management are facilitated.

[0035] Input and output module: two-stage alarm signals can be output for shaft voltage, shaft current and shaft insulation parameters, so as to remind workers to take measures in time.

[0036] As shown in Figure 2 The utility model discloses a kind of shaft voltage, shaft current and shaft insulation measurement devices, as shown in Fig. 1, all circuits of the utility model are provided with working power supply by two-way switching power supply PW1, PW2 as main and standby for each other;T1, T2, T3 are shaft voltage measurement module, shaft current measurement module, shaft insulation measurement module respectively;3 parts of module input corresponding signal collected to control core PLC (U1), after data depth processing by PLC, output shaft voltage, shaft current, shaft insulation parameter value, corresponding by LED1, LED2, LED3 digital display module and touch screen TPC two kinds of display at present, digital module and touch screen have man-machine bidirectional operation function between PLC, core PLC will be measured data after processing output analog quantity, and switching value alarm;The system is communicated with external communication system in real time by RS485.

[0037] The installation steps of the utility model

[0038] Shaft current sensor installation: according to the diameter of the generator shaft and the size of the current, select the appropriate size of the shaft current sensor. Before installation, remove the connecting wire on the sensor, the screw on the connecting plate. Put the two half rings on the generator shaft, make sure the gap between the two half rings is less than 0.1mm, fix them into a whole ring with screws, make the gap between the sensor and the generator shaft as uniform as possible, and the fixed sensor should not be loose. According to the wiring requirements, connect the two red terminals (a, a) next to each other, connect the two black terminals (b, b), then connect the other two red terminals (A1, A2) to the A1 and A2 of the instrument, and connect the two black terminals (B1, B2) to the B1 and B2 of the instrument.

[0039] Shaft insulation pre-installer installation: A terminal device terminal XB2:11, B terminal device terminal XB2:12, POWER terminal device terminal XB2:9, 10 (AC / DC universal, no positive and negative). RX2 is connected to the generator shaft grounding carbon brush, RX1 is connected to the shaft ring carbon brush, COM is connected to the copper foil carbon brush, and the connection is firm to avoid poor contact affecting the measurement accuracy.

[0040] Overall installation of the device: according to the size of the device (484x326x142mm) and the size of the opening (452+1x138+1mm), open the hole on the installation plate. Install the device in the appropriate position and fix it through the installation hole (4-φ7, panel thickness 10mm) to ensure that the device is installed stably.

[0041] Parameter setting of the utility model

[0042] Key operation: press the set key for 2 seconds to enter the parameter setting interface. Modify the lock value by increasing or decreasing the key, and press the set key under each lock value to enter the corresponding menu. For example, from lock value 18883, enter the shaft voltage alarm parameter setting to set the shaft voltage first alarm value, alarm delay, alarm hysteresis and other parameters; from lock value 18884, enter the shaft current alarm parameter setting; from lock value 18885, enter the shaft insulation alarm parameter setting; from lock value 18886, enter the communication parameter setting.

[0043] Touch screen operation: automatically enter the monitoring main screen after starting, display the shaft voltage, shaft current, shaft insulation real-time measurement value, parameter alarm setting value and alarm state, etc. Click the "parameter setting" button at the bottom of the screen to pop up the user login window (no password by default when leaving the factory, the login password can be manually set in the user management of parameter setting), click the login button to enter the parameter setting interface. In this interface, alarm parameter setting (including shaft voltage, shaft current, shaft insulation alarm parameter), user management (setting login password), system time setting, MODBUS communication setting and other operations can be performed. Click the "confirm" button after modifying the parameters to make the parameters effective.

[0044] During the operation of the device, the shaft voltage measurement module, the shaft current measurement module and the shaft insulation measurement module collect data in real time, and transmit the processed data to the PLC. The PLC judges according to the preset alarm threshold value, and when the shaft voltage and the shaft current exceed the upper threshold value, or the shaft insulation is lower than the lower threshold value, the corresponding alarm signal is triggered immediately. At this time, the state indicating lamp (Voltage H HH, Current H HH, Insulation H HH) is on, reminding the on-site staff. At the same time, the alarm information will be recorded in the alarm record, which can be viewed by clicking the "alarm record" button at the bottom of the main screen. The record includes the detailed time of the alarm occurrence and end, and the running state of the device.

[0045] The device integrates an RS485 communication interface and follows the MODBUS RTU protocol. When the host computer sends a command, the function code 03 is used to read the analog quantity, and the function code 01 is used to read the switch quantity, and the data is sent according to the specified command format. After receiving the command, the device reads and processes the data according to the command requirements, and returns the data according to the response format, realizes the data communication between the host computer, and facilitates remote monitoring and management.

[0046] The working process of the utility model:

[0047] During the operation of the whole device, the shaft voltage measurement module, the shaft current measurement module and the shaft insulation measurement module continuously collect corresponding signals and process them respectively. The processed signals are transmitted to the PLC controller. The PLC controller, as the core control unit of the whole device, comprehensively calculates and analyzes these signals. It compares the real-time measurement values of shaft voltage, shaft current and shaft insulation received with the pre-set alarm threshold values. Once the measurement value of a certain parameter exceeds the corresponding alarm threshold value, the PLC will immediately trigger an alarm signal. On the one hand, the alarm signal is output through the output module to output two-level switch quantity alarm signal, driving external alarm devices such as indicator light, alarm, etc., to remind the on-site staff; on the other hand, the relevant alarm information will be recorded and stored in the storage unit inside the device, facilitating subsequent query and analysis. At the same time, the effective value, fundamental value and harmonic value of shaft voltage and shaft current, as well as the shaft insulation measurement value, will also be output through the analog quantity output module to output 4-20mA analog signal, so as to interact and share data with other devices. In addition, the display module will display the measurement values of shaft voltage, shaft current, shaft insulation and the running state of the device in real time, so as to facilitate the operator to understand the shaft electric quantity of the unit at any time. The communication module communicates with the whole plant computer monitoring system through the RS485 interface and follows the MODBUS RTU protocol, realizes the function of remote monitoring and management, so that the staff can monitor and control the shaft electric quantity of the unit in the remote monitoring center.

[0048] Many specific details are set forth in the above description in order to provide a thorough understanding of the application. However, the application can be practiced according to other embodiments that do not require the specific details described above. Therefore, the scope of the present application is not limited to the above-described embodiments.

[0049] The preferred embodiments of the present application have been described above with the specific details. Obviously, the present application can be implemented in other different ways not described here, and therefore the protection scope of the present application is not limited to the above disclosed specific embodiments.

Claims

1. A shaft electric quantity monitoring protection device, characterized in that, The application relates to a generator shaft voltage, current and insulation measuring device which comprises a shaft voltage measuring module, a shaft current measuring module, a shaft insulation measuring module, a PLC controller, a display module, a communication module and an input / output module. The shaft voltage measuring module detects a shaft voltage signal through shaft voltage carbon brushes (1) and grounding carbon brushes (9) connected to both sides of a generator shaft rotor. The shaft current measuring module detects a shaft current signal through a shaft current sensor arranged on the generator shaft. The shaft insulation measuring module monitors the insulation resistance value between a copper foil (2) of a generator insulation layer and a shaft (8) and between the copper foil (2) and a shaft ring (6) through a shaft insulation preamplifier (10).

2. The shaft electric quantity monitoring protection device according to claim 1, characterized in that, The display module displays the measurement values of the shaft voltage, the shaft current and the shaft insulation through LED nixie tubes.

3. The shaft electricity quantity monitoring protection device according to claim 1 or 2, characterized in that, The input / output module is used for receiving the signals of the PLC controller and outputting the shaft voltage, the shaft current and the shaft insulation parameters and two-stage alarm signals.

4. The shaft electricity quantity monitoring protection device according to claim 3, characterized in that, The shaft current sensor is arranged around the generator shaft.

5. The shaft electricity quantity monitoring protection device according to claim 4, characterized in that, The model of the PLC controller is ST30.

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