CN107144787A - The generator insulating detection means and detection method of a kind of permanent-magnetic wind driven generator - Google Patents

Abstract

The invention discloses a generator insulation detection device for a permanent magnet wind power generator. The generator insulation detection device includes: PLC, power supply, communication module, touch screen, I/O module, constant voltage source, voltmeter, ammeter , discharge resistors, fuses, overvoltage protection devices, contactors, transmitters, intermediate relays, junction boxes and temperature sensors. , automatically test the insulation resistance, and diagnose the insulation by detecting the generator stator insulation resistance, polarization index, absorption ratio and trend curve.

Description

Generator insulation detection device and detection method of a permanent magnet wind power generator

technical field

The invention relates to the technical field of wind power, in particular to a generator insulation detection device and a detection method of a permanent magnet wind power generator.

Background technique

As the mainstream model of large-scale wind turbines, permanent magnet wind turbines have a very high market share. Due to the climatic environment in which the wind turbine works has the characteristics of large temperature difference between day and night, large wind and sand, high humidity in some areas, and condensation, these environmental factors will affect the insulation system of the wind turbine, and the maintenance of the damaged wind turbine And lifting costs are very expensive.

Due to the particularity of the operating environment of wind turbines, on-site testing is very difficult. For daily maintenance monitoring, the method of manual shutdown detection is basically adopted. Using a megohmmeter to measure the insulation resistance of the generator set is not only inefficient, but also requires shutdown testing, which greatly increases the cost of operation and maintenance.

At present, the insulation state of generator sets at home and abroad is usually characterized by the characteristic values of partial discharge, dielectric loss factor, leakage current, insulation resistance and equipment capacitance.

Among them, Hunan Institute of Engineering published the patent of CN204716470U "A Megawatt-level Wind Power Generator with Insulation Online Monitoring Function". This patent mainly detects the ozone content by installing ozone sensors on different parts of the generator. Determine the intensity and location of partial discharge, which indirectly reflects the insulation status of the generator.

Nanjing Wind Power Science and Technology Co., Ltd. has published the authorized announcement number: CN202441544U's patent "A Wind Power Generator with Insulation Detection Function", which is also equipped with an ozone sensor.

The above two patents only have a certain effect on the detection of partial insulation defects of windings, but the partial discharge test can only indirectly reflect the insulation state.

Therefore, it is desired to have a generator insulation detection device and detection method for a permanent magnet wind power generator that can overcome or at least alleviate the above-mentioned defects of the prior art.

Contents of the invention

The purpose of the present invention is to provide a generator insulation detection device and detection method for a permanent magnet wind power generator, which can automatically test the insulation resistance during the normal shutdown time under the condition of low wind speed of the wind turbine, and detect the insulation resistance of the generator stator. Resistance, polarization index, absorption ratio and trend curves for insulation diagnosis.

In order to achieve the above object, the present invention provides a generator insulation detection device for a permanent magnet wind power generator. The generator insulation detection device includes: PLC, power supply, communication module, touch screen, I/O module, constant voltage source, Voltmeter, ammeter, discharge resistor, fuse, overvoltage protection device, contactor, transmitter, intermediate relay, junction box and temperature sensor; wherein, the ammeter includes a first ammeter and a second ammeter, and the transmitter includes a voltage transformer Transmitter, current transmitter and temperature transmitter, the contactor includes the first contactor, the second contactor and the third contactor, the PLC is respectively connected to the communication module and the touch screen through the communication line, and the communication module is connected to the touch screen through the communication line The control system of the permanent magnet wind turbine is connected. The PLC is connected to the I/O module through the backplane communication line. The multiple output terminals of the I/O module are respectively connected to the intermediate relay and the contactor. The transmitter is connected to the secondary side of the voltmeter, the analog input terminal of the PLC is connected to the secondary side of the first ammeter and the second ammeter through the current transmitter, and the analog input terminal of the PLC is connected to the temperature sensor through the temperature transmitter; constant voltage The source, the fuse, the first ammeter and the second contactor are connected in parallel with the primary side of the voltmeter after being connected in series, the two ends of the voltmeter are connected in parallel with the overvoltage protection device, and the third contactor, the second ammeter and the discharge resistor are connected in parallel in series to A branch circuit of the constant voltage source, one end of the branch circuit of the constant voltage source is connected to the generator stator terminal through the first contactor, and the other end is connected to the grounding terminal.

Preferably, the power supply takes a 220V power supply from the low-voltage grid side of the step-up transformer of the permanent magnet wind power generating set, and provides a 220V AC power supply for the constant voltage source. The constant voltage source is the control system of the PLC, the touch screen, Communication modules, I/O modules, voltmeters, ammeters, contactors and intermediate relays provide 24V DC power.

Preferably, the generator insulation detection device also includes a hardware safety chain system and a software safety chain system; the hardware safety chain system connects the auxiliary normally closed contact of the contactor KM0 in series with the drive control circuit of the contactor KM1 to form a lock, and the software safety The chain system is used to periodically detect the running time of the control system. When the program of the control system runs incorrectly or exceeds the detection time limit, the control system restarts.

Preferably, the constant voltage source is a continuously adjustable DC constant voltage power supply, the output rated voltage range of the constant voltage source is 1kV-12kV, and the rated current range is 50mA-1A.

Preferably, the discharge resistor is used to consume the remaining charge in the winding of the permanent magnet wind power generator, the resistance range of the discharge resistor is: 10kΩ-100kΩ, and the power is greater than or equal to 50 watts.

The invention provides a detection method for a generator insulation detection device of a permanent magnet wind power generator, comprising the following steps:

(1) Obtain the working state of the permanent magnet wind generator through the PLC, the communication device and the permanent magnet wind generator control system. The detection time of the device and when the PLC internal timer reaches the detection cycle, start the generator insulation detection device;

(2) When the start-up time of the generator insulation detection device meets the requirements, close the contactor KM1 and keep the contactor KM2 and contactor KM3 in an open state, measure the generator stator voltage through the voltmeter, when the stator voltage is less than 600V , close the contactor KM3, and use the discharge resistor to discharge the residual charge of the generator stator. The discharge time is greater than or equal to 20 seconds. When the current value measured by the first ammeter through the discharge resistor is less than 0.1A, delay 5 Disconnect the contactor KM3 in seconds;

(3) After the discharge process is over, select the absorption ratio measurement mode according to the working conditions, connect the contactor KM2 to apply the constant voltage source on the generator stator, and record the voltmeter and ammeter respectively in 15 seconds during the pressurization process and the data at 60 seconds, calculate the insulation resistance values at 15 seconds and 60 seconds respectively, and calculate the absorption ratio of the stator winding, perform normalization according to the actual temperature and humidity on site, and use the normalized insulation resistance Value and absorption ratio to judge the insulation status of generator set stator;

(4) After the discharge process is over, select the polarization index measurement mode according to the working conditions, connect the contactor KM2 to apply the constant voltage source on the generator stator, and record the voltmeter and ammeter respectively in 1 minute during the pressurization process. and the data at 10 minutes, calculate the insulation resistance values at 1 minute and 10 minutes respectively, and calculate the polarization index of the stator winding, and perform normalization processing according to the actual temperature and humidity on site, and use the normalized insulation resistance value and Polarization index to judge the insulation state of generator set stator;

(5) Through continuous detection and calculation, record the absorption ratio of the generator stator winding, and draw the generator stator insulation absorption ratio curve; through continuous detection and calculation, record the polarization index of the generator stator winding, and draw the generator stator insulation polarization Exponential curve, and record in the storage unit of described PLC, described instruction PLC single measurement is finished;

(6) After a single measurement, first disconnect the contactor KM2, and then connect the contactor KM3 to release the residual power of the generator winding. When the voltage measured by the voltmeter is less than 50V, disconnect the contactor KM3 and the contactor KM1, the system enters the automatic timing program for the next detection, and the PLC sends a signal to the control system of the permanent magnet wind power generating set, and the generator insulation detection is completed.

The present invention proposes a generator insulation detection device and detection method of a permanent magnet wind power generator. The generator insulation detection device of the permanent magnet wind power generator of the present invention is arranged at the stator outlet terminal and the grounding terminal of the permanent magnet wind power generator , the generator insulation detection device automatically tests the insulation resistance during the low wind speed and normal shutdown time of the wind turbine, and the insulation resistance measured by the generator insulation detection device of the present invention can not only be normalized for the on-site working environment , and the polarization index and absorption ratio of the insulation can be counted, and the trend curve of the insulation resistance, absorption ratio and polarization index can be used to reflect the insulation trend of the generator, so as to determine the insulation state of the generator and formulate maintenance and maintenance plans. Significantly improve the operation and maintenance efficiency of wind turbines and reduce operation and maintenance costs.

Description of drawings

Fig. 1 is a schematic structural diagram of a generator insulation detection device for a permanent magnet wind power generator.

Fig. 2 is a schematic diagram inside the control cabinet of the generator insulation detection device of the permanent magnet wind power generator.

detailed description

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below in conjunction with the drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of the invention. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, the generator insulation detection device of the permanent magnet wind turbine includes a detection control cabinet, a junction box, and a temperature sensor, and the detection control cabinet includes: PLC, power supply, communication module, touch screen, and I/O module , Constant voltage source, voltmeter, ammeter, discharge resistor, fuse, overvoltage protection device, contactor, transmitter and intermediate relay.

In the control system, the PLC is connected to the communication module and the touch screen through the communication line, the communication module is connected to the control system of the wind turbine through the communication line, and the PLC is connected to the I/O module through the backplane communication line. The output terminals are respectively connected to the intermediate relay and the contactor, the PLC analog input terminal is connected to the secondary side of the voltmeter through the voltage transmitter, and the PLC analog input terminal is connected to the secondary side of the ammeter 1 and ammeter 2 through the current transmitter. The PLC analog input terminal is connected with the temperature sensor through the temperature transmitter.

The power supply takes 220V power from the low-voltage power grid side of the step-up transformer of the wind turbine, and provides 220V AC power for the constant voltage source. The constant voltage source is the PLC control system, touch screen, communication module, I/O module, voltmeter, ammeter, contact The device and the intermediate relay provide 24V DC power supply.

The detection device uses relays, contactors and the internal timer system of PLC to realize the safety chain system. The hardware safety chain system is to connect the auxiliary normally closed contact of the contactor KM0 in series to the drive control circuit of the contactor KM1 to form a lock. The software safety chain The system periodically detects the running time of the control system. If the system program runs incorrectly or exceeds the detection time limit, the system will be restarted.

The constant voltage source of the detection device is a continuously adjustable DC constant voltage power supply, the output rated voltage range is 1kV-12kV, and the rated current range is 50mA-1A. It mainly provides a stable voltage source for the insulation detection system. Usually the applied voltage is 1kV, and the voltage can be adjusted according to the requirements of generator insulation detection.

The discharge resistor consumes the residual charge in the generator winding, and the discharge resistor is used to prevent the residual charge of the system from affecting the measurement accuracy of the detection system. The selection of the generating resistor is mainly to consider the amount of charge stored in the equivalent capacitance of the generator winding, which is consumed within the time required by the detection system.

The junction box is used to connect the outlet wire of the generator stator winding and the system ground wire, and then connect the corresponding terminals with the terminals in the detection control cabinet through the cable tube to facilitate system wiring.

The temperature sensor is a thermocouple placed inside the generator set to detect the temperature of the generator winding and inside the generator. When the generator performs insulation detection, the ambient temperature is different from the state of the generator itself. The insulation resistance of the test should also be converted. The insulation resistance of the generator is normalized by using the temperature conversion relation.

As shown in Figure 2, a generator insulation detection device for a permanent magnet wind turbine, the internal principle is to connect a constant voltage source, a fuse, an ammeter 1 and a contactor KM2 in series and then connect them in parallel with the primary side of the voltmeter, and the voltmeter The two ends are connected in parallel with the overvoltage protection device, and the contactor KM3, the ammeter 2 and the discharge resistor are connected in series and then connected in parallel to the constant voltage source branch. One end of the constant voltage source branch is connected to the generator stator terminal through the contactor KM1, and the other One end is connected to the ground terminal.

A detection method of a generator insulation detection device of a permanent magnet wind power generator comprises the following steps:

(1) Obtain the working state of the wind turbine through the PLC, communication device and wind turbine control system. When the wind turbine is in the normal stop state and restart state time is longer than the detection time of the generator insulation detection device and the PLC internal timing When the generator reaches the detection cycle, start the generator insulation detection device;

(2) When the start-up time of the generator insulation detection device meets the requirements, close the contactor KM1 and keep the contactor KM2 and contactor KM3 in an open state, measure the generator stator voltage through the voltmeter, when the stator voltage is less than 600V , close the contactor KM3, and use the discharge resistor to discharge the residual charge of the generator stator. The discharge time is greater than or equal to 20 seconds. When the current value measured by the first ammeter through the discharge resistor is less than 0.1A, delay 5 Disconnect the contactor KM3 in seconds;

(3) After the discharge process is over, select the absorption ratio measurement mode according to the working conditions, connect the contactor KM2 to apply the constant voltage source on the generator stator, and record the voltmeter and ammeter respectively in 15 seconds during the pressurization process and the data at 60 seconds, calculate the insulation resistance values at 15 seconds and 60 seconds respectively, and calculate the absorption ratio of the stator winding, and perform normalization processing according to the actual temperature and humidity on site, and use the normalized resistance value Determine the insulation state of the stator of the generator set based on the absorption ratio and set the threshold value, and the insulation resistance value is 0.5 megohm lower. Alert the detection value. When the absorption ratio is less than 1.2, alarm processing is carried out;

(4) After the discharge process is over, select the polarization index measurement mode according to the working conditions, connect the contactor KM2 to apply the constant voltage source on the generator stator, and record the voltmeter and ammeter respectively in 1 minute during the pressurization process. and the data at 10 minutes, calculate the insulation resistance values at 1 minute and 10 minutes respectively, and calculate the polarization index of the stator winding, and perform normalization processing according to the actual temperature and humidity on site, and use the normalized insulation resistance value and The polarization index judges the insulation state of the stator of the generator set, and sets the threshold value. When the polarization index is less than 1.3, an alarm is issued;

(5) Through continuous detection and calculation, record the absorption ratio of the generator stator winding, and draw the generator stator insulation absorption ratio curve; through continuous detection and calculation, record the polarization index of the generator stator winding, and draw the generator stator insulation polarization Exponential curve, and record in the storage unit of described PLC, described instruction PLC single measurement is finished;

(6) After a single measurement, first disconnect the contactor KM2, and then connect the contactor KM3 to release the residual power of the generator winding. When the voltage measured by the voltmeter is less than 50V, disconnect the contactor KM3 and the contactor KM1, the system enters the automatic timing program for the next detection, and the PLC sends a signal to the control system of the wind power generating set to complete the detection.

Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: they can still modify the technical solutions described in the aforementioned embodiments, or perform equivalent replacements for some of the technical features; and these The modification or replacement does not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (6)

1. a kind of generator insulating detection means of permanent-magnetic wind driven generator, it is characterised in that the generator insulating detection dress Put including：It is PLC, power supply, communication module, touch-screen, I/O modules, constant pressure source, voltmeter, ammeter, discharge resistance, molten Disconnected device, over-pressure safety device, contactor, transmitter, auxiliary reclay, terminal box and temperature sensor；Wherein, ammeter includes First ammeter and the second ammeter, transmitter include voltage transmitter, current transducer and temperature transmitter, and contactor includes First contactor, second contactor and the 3rd contactor, PLC are connected with communication module and touch-screen respectively by connection Connect, communication module is attached by connection and the control system of permanent-magnetic wind driven generator group, PLC by backboard connection with I/O modules are connected, and multiple output ends of I/O modules are attached with auxiliary reclay and contactor respectively, PLC simulation input End by voltage transmitter and the secondary side joint of voltmeter, PLC analog input end by current transducer and the first ammeter and The secondary side joint of second ammeter, PLC analog input end connects temperature sensor by temperature transmitter；Constant pressure source, fuse, Primary side after first ammeter and second contactor series connection with voltmeter is in parallel, and voltmeter two ends and over-pressure safety device are simultaneously Connection, is connected in parallel to the branch road of constant pressure source after the 3rd contactor, the second ammeter and discharge resistance series connection, branch road one end of constant pressure source leads to Cross first contactor with generator unit stator binding post to be connected, the other end is connected with ground connection binding post.

2. the generator insulating detection means of permanent-magnetic wind driven generator as claimed in claim 1, it is characterised in that：The power supply Power supply provides 220V for the constant pressure source and handed over from the step-up transformer low voltage electric network side draw 220V power supplys of permanent-magnetic wind driven generator group Power supply is flowed, the constant pressure source is the control system of the PLC, touch-screen, communication module, I/O modules, voltmeter, ammeter, connect Tentaculum and auxiliary reclay provide 24V dc sources.

3. the generator insulating detection means of permanent-magnetic wind driven generator as claimed in claim 1, it is characterised in that：It is described to generate electricity Machine insulation detection device also includes hardware security catenary system and software security catenary system；Hardware security catenary system is by contactor KM0 Auxiliary normally-closed contact and contactor KM1 the formation locking of drive control circuit in series, software security catenary system is used for periodically The run time of the control system is detected, when the control system program run-time error or more than detection time limit, the control System carries out restarting processing.

4. the generator insulating detection means of permanent-magnetic wind driven generator as claimed in claim 1, it is characterised in that：The constant pressure Source is the DC constant voltage power supply of continuously adjustabe, and the output rated voltage scope of the constant pressure source is 1kV~12kV, rated current model Enclose for 50mA~1A.

5. the generator insulating detection means of permanent-magnetic wind driven generator as claimed in claim 1, it is characterised in that：The electric discharge Resistance is used to consume remaining electric charge in permanent-magnetic wind driven generator winding, and the Standard resistance range of the discharge resistance is：10kΩ- 100k Ω, power is more than or equal to 50 watts.

6. a kind of detection method of the generator insulating detection means of the permanent-magnetic wind driven generator described in usage right requirement 1, its It is characterised by, comprises the following steps：

(1) work of permanent-magnetic wind driven generator is obtained by the PLC, communication device and permanent-magnetic wind driven generator set control system State, is examined when permanent-magnetic wind driven generator group is in orderly closedown state or is again started up state for time more than the generator insulating When the detection time and the PLC timer internals for surveying device reach detection cycle, start the generator insulating detection dress Put；

(2) when the startup time satisfaction of the generator insulating detection means is required, close contactor KM1 and simultaneously keep contactor KM2 and contactor KM3 is in open mode, generator unit stator voltage is measured by the voltmeter, when stator voltage is less than During 600V, contactor KM3 is closed, generator unit stator residual charge is discharged using the discharge resistance, discharge time is big In equal to 20 seconds, when first ammeter, which is measured, is less than 0.1A by the current value of the discharge resistance, postpone to break for 5 seconds Open contactor KM3；

(3) after discharge process terminates, absorptance measurement pattern is selected according to working condition, contactor KM2 is connected fixed in generator Apply the number for recording the voltmeter and ammeter in the constant pressure source, pressure process respectively at 15 seconds and 60 seconds on son According to, insulating resistance value when calculating respectively 15 seconds and 60 seconds, and the absorptance of stator winding is calculated, according to live actual Temperature and humidity is normalized, using normalizing insulating resistance value and absorptance judges that Stator insulate shape State；

(4) after discharge process terminates, polarization index measurement pattern is selected according to working condition, contactor KM2 is connected in generator Apply on stator and record the voltmeter and ammeter in the constant pressure source, pressure process respectively at 1 minute and 10 minutes Data, insulating resistance value when calculating respectively 1 minute and 10 minutes, and the polarization index of stator winding is calculated, according to scene Actual temperature and humidity are normalized, using normalizing insulating resistance value and polarization index judges that Stator is exhausted Edge state；

(5) by continuously detecting calculating, the absorptance of generator unit stator winding is recorded, generator stator insulator absorptance is drawn Curve；By continuously detecting calculating, the polarization index of generator unit stator winding is recorded, generator stator insulator polarization is drawn and refers to Number curve, and record in the memory cell of the PLC, the instruction PLC single measurements are finished；

(6) after single measurement is finished, contactor KM2 is disconnected first, contactor KM3 is connected afterwards, carries out generator windings remaining Electricity discharges, and when voltmeter measurement voltage is less than 50V, disconnects contactor KM3 and contactor KM1, system enters next Secondary detection self-clocking program, the PLC sends a signal to the control system of permanent-magnetic wind driven generator group, generator insulating detection Finish.