A wind turbine insulation resistance online monitoring instrument and monitoring method

Abstract

The invention relates to the field of online monitoring instruments for insulation resistance of wind power generators, and discloses an online monitoring instrument for insulation resistance of wind power generators, comprising a first detection voltage output port and a second detection voltage output port respectively connected to a stator winding and a rotor winding of a generator, wherein the first detection voltage output port is connected to a first relay, and a normally open contact of the first relay is grounded. The scheme also provides an online detection method for insulation resistance of a wind power generator. The online monitoring instrument for insulation of a wind power generator of the invention is used in conjunction with a wind power generator, and can respectively detect three groups of insulation resistance value parameters, namely, insulation resistance value of a stator winding to ground, insulation resistance value of a rotor winding to ground, and insulation resistance value between a stator and a rotor.

Description

Technical Field

[0001] The present invention relates to the field of wind turbine monitoring, and more specifically, to an online monitoring instrument and monitoring method for insulation resistance of a wind turbine. Background Art

[0002] With the continuous promotion and application of clean energy such as solar energy, wind energy, tidal energy, biomass energy and other renewable energy, especially the continuous maturity of wind energy technology, the economic feasibility value is high, and it is an ideal development energy. Compared with other energy sources, wind energy has obvious advantages: huge reserves, wide distribution, no pollution, and is an inexhaustible renewable energy; wind power generation has no fuel problem, does not produce radiation or carbon dioxide pollution, and does not produce radiation or air pollution; and from an economic point of view, wind power instruments are more than 90% cheaper than solar power instruments. China has a large wind energy reserve and a wide distribution area, even richer than hydropower. Reasonable use of wind energy can not only reduce environmental pollution, but also alleviate the increasing pressure of energy shortage. From the current technical maturity and economic feasibility, wind energy is the most competitive. In the medium term, the prospects of the global wind energy industry are quite optimistic. The renewable energy incentive policies continuously introduced by governments will provide huge impetus for the rapid development of the industry in the next few years. According to estimates, Asia and America will become the regions with the greatest growth potential in the next few years. China's wind power installed capacity will achieve a high growth rate of 30% per year. Therefore, the prospect of wind power generation is very promising, and the amount of investment in wind power equipment is also very huge.

[0003] Since the kinetic energy of wind power generation is wind, and wind power equipment is installed in the wilderness or shallow sea level, the engine will stop running when there is no wind, and the engine equipment will gradually cool down from heat. At this time, the equipment is most susceptible to corrosion damage from moisture and salt corrosion, which will seriously cause the insulation value of the engine equipment to decrease, and even cause its insulation resistance to the ground to drop to zero ohm. If the engine is forced to start and run when the wind comes at this time, it will cause property losses such as burning of the main equipment of the engine. Therefore, according to customer needs and market research results, an insulation online monitoring device "ZZFNJKY-I Wind Power Generator Insulation Resistance Online Monitor" has been developed for the characteristics of wind power generators. The invention of this insulation online monitor can well solve the insulation of the stator and rotor windings of the generator equipment to the ground and the insulation decline or short circuit between the stator and rotor windings. When problems are found, alarms are issued in time and the equipment is locked, so as to deal with them as soon as possible to avoid property losses such as equipment burning.

[0004] As wind power generation is still in the development stage, online insulation monitoring equipment for wind turbines is still imperfect or even non-existent. Traditional testing is done by manual shaking table, which is a one-time test before the equipment is installed and put into operation. It is no longer tested at a later stage due to various reasons such as heavy workload and inconvenience. Online testing and remote communication are impossible, so it is impossible to detect problems and lock the protection equipment in time. Summary of the invention

[0005] The purpose of the present invention is to provide an online monitoring instrument and monitoring method for the insulation resistance of a wind turbine generator. The purpose of the present invention is to solve the above-mentioned problem that the insulation of the equipment cannot be detected online. The insulation detection equipment is required to be able to detect online and be able to complete functions such as alarm locking, remote communication, alarm recording, and human-computer dialogue.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A wind turbine insulation resistance online monitoring instrument comprises a first detection voltage output port and a second detection voltage output port respectively connected to a stator winding and a rotor winding of a generator, wherein the first detection voltage output port is connected to a first relay K1, a normally open contact of the first relay K1 is grounded, a normally closed contact of the first relay K1 is connected to one of a normally open contact and a normally closed contact of a third relay K3, and the second detection voltage output port is connected to a second relay K2, a normally open contact of the second relay K2 is grounded, a normally closed contact of the second relay K2 is connected to a normally open contact of the third relay K3. And another connection in the normally closed contact, access to the detection voltage through the third relay K3, the wind power generator insulation online monitoring device of the present invention is used in conjunction with the wind power generator, and can respectively detect the insulation resistance value of the stator winding to the ground, the insulation resistance value of the rotor winding to the ground, the insulation resistance value between the stator and the rotor, etc., a total of three groups of insulation resistance value parameters, as well as the absorption ratio of the above three groups of insulation resistance values, and remotely transmit them to the central control room, so that technical personnel can analyze the quality of the generator, arrange repairs and maintenance work as soon as possible, ensure the normal operation of the generator will not be damaged due to faults, and maximize the operation efficiency of the generator.

[0008] Furthermore, a first isolation resistor R1 is provided between the stator winding and the first detection voltage output port, and a second isolation resistor R2 is provided between the rotor winding and the second detection voltage output port. The isolation resistor may be a single resistor or a plurality of resistors connected in parallel.

[0009] Furthermore, the detection voltage connected to the third relay K3 is a direct current of 500V, and the specific data of the detection voltage should not be a limitation of the present invention.

[0010] Furthermore, the first relay K1 , the second relay K2 and the third relay K3 are all reed switch relays.

[0011] The present scheme also provides an online detection method for the insulation resistance of a wind turbine generator, S1, determining whether the generator is in a shutdown state, if so, proceeding to step S2; S2, grounding the stator winding and rotor winding of the generator, and setting a time for ground discharge; S3, applying voltage to the stator winding and the rotor winding respectively, measuring the insulation resistance data of the stator winding and the rotor winding to the ground in real time, and comparing the data with a preset insulation resistance threshold to the ground in real time; if the data is less than the preset threshold, proceeding to step S4, and extracting the insulation resistance data of the stator winding and the rotor winding to the ground at multiple time nodes during the real-time measurement process, calculating the absorption ratio parameter, comparing the absorption ratio parameter with the preset absorption ratio parameter threshold, if the data is less than the absorption ratio parameter threshold, proceeding to step S4; S4, sending an alarm signal to the terminal, disconnecting the generator circuit, and repeating step S1.

[0012] Furthermore, the voltage applied in step S3 is a DC voltage of 500V.

[0013] Furthermore, the insulation resistance to ground in step S3 is 5 MΩ.

[0014] Furthermore, the multiple time nodes in step S3 include the insulation resistance to ground at 15s and 60s, and the absorption ratio parameter is equal to the insulation resistance to ground at 60s divided by the insulation resistance to ground at 15s, which can also be other preferred values, which should not be a limitation of the present invention.

[0015] Furthermore, between step S3 and step S4, there is also a detection of the stator winding to the rotor winding, and the specific steps include: S351, grounding the stator winding and the rotor winding of the generator, and setting the time for ground discharge; S352, grounding the second detection voltage output port, and applying voltage between the stator winding and the rotor winding, measuring the insulation resistance data between the stator winding and the rotor winding to the ground in real time and comparing it with the preset insulation resistance threshold to the ground in real time. If it is less than the preset threshold, step S4 is performed, and in the process of real-time measurement, the insulation resistance between the stator winding and the rotor winding to the ground at multiple time nodes is extracted, and the absorption ratio parameter is calculated, and the absorption ratio parameter is compared with the preset absorption ratio parameter threshold. If it is less than the absorption ratio parameter threshold, step S4 is performed.

[0016] Compared with the prior art, the advantages of the present invention are:

[0017] 1. Operation display of wind turbine insulation monitor: dual 4-digit digital tube display windows are used to display the corresponding winding position number and its static insulation resistance value respectively; static insulation resistance value and fault alarm record are available for review, with a total of 21 groups of historical alarm records; when the static insulation resistance is too low, the corresponding display value flashes to alarm; when the insulation value drops to the preset value, the corresponding control output relay KJ and KS passive contact output of the monitor will be actuated.

[0018] 2. The wind turbine insulation monitor is equipped with two DC500V detection voltage output terminals, namely 1Y and 2Y output ports, which are connected to the stator and rotor windings of the generator through two 1MΩ isolation resistors respectively. The casing of the generator and the 17 terminal (earth) of the insulation monitor are connected to form a detection loop. Four sets of dry yellow tube relays are set inside the insulation monitor. The software is used to realize the discharge and charging of the generator winding to the ground. The relay is switched every 60 seconds to realize the insulation value detection of the stator and rotor windings of the generator to the ground and the insulation value detection between the stator and rotor windings of the generator, and the insulation absorption ratio parameters of the stator, rotor and stator-rotor windings are recorded respectively to realize the measurement and alarm functions.

[0019] 3. The wind turbine insulation monitor is equipped with a reed switch relay K, which is used to connect with the normally closed contact of the vacuum circuit breaker on the external control cabinet or the normally closed auxiliary contact of the start circuit to control the 1Y and 2Y high-voltage outputs of the wind turbine insulation monitor. When the auxiliary contact is closed, there is high-voltage output, otherwise there is no high-voltage output. It is used to detect the insulation value of each winding to ground insulation resistance of the generator when it is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a partial structural schematic diagram of the relay control circuit in the present invention;

[0022] Figure 2 It is a partial structural schematic diagram of the relay control circuit in the present invention;

[0023] Figure 3 It is the instrument power supply diagram in the present invention. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0025] Embodiment 1:

[0026] See also Figure 1 , Figure 2 , Figure 3 As shown, the state of the external relay K of the instrument determines whether the motor is in the start / stop state. When the external relay K is closed, it means that the generator is in the stop state, otherwise it is in the start state. When the generator is in the stop state, the controller allows the stator, rotor winding and the stator-rotor winding to be pressurized for measurement preparation, including the stator and rotor winding discharge to the ground.

[0027] When the external relay K is in the closed state, the controller's internal reed switch relays K1 and K2 are changed from normally closed contacts to normally open contacts according to the command. At this time, the 1Y and 2Y terminals are connected to the ground through the normally open contacts of K1 and K2. The stator and rotor windings of the generator are connected to 1Y and 2Y through the isolation resistors R1 and R2 respectively. After discharging to the ground for 1 minute, the reed switch relays K1 and K2 are changed from normally open to normally closed again. At this time, the controller's internal relay K3 is converted from normally closed to normally open connection in sequence. The DC 500V voltage is applied to the generator stator winding through the instrument 1Y output port, and the insulation values ​​of 15 seconds and 60 seconds are recorded at the same time; then the DC 500V voltage is applied to the rotor winding through the instrument 2Y output port, and the insulation values ​​of 15 seconds and 60 seconds are recorded at the same time; according to the program command, the reed switch relays K1 and K2 inside the controller are changed from normally closed contact connection to normally open contact connection. At this time, the 1Y and 2Y ports are connected to the ground through the normally open contacts of the K1 and K2 relays respectively, and the stator and rotor windings of the generator are connected to the 1Y and 2Y ports through the isolation resistors R1 and R2 respectively. After being discharged to the ground for 1 minute, the reed switch relay K1 changes from normally open to normally closed connection state, and K2 Keep the normally open connection unchanged and connected to the ground. At this time, K3 keeps the normally closed connection, and is connected to the 1Y port through the normally closed contact of K1. 1Y is connected to the stator winding through the isolation resistor R1. At this time, the generator rotor winding is connected to the isolation resistor R2 and then connected to the K2 normally open contact and the ground through the 2Y port. The generator and the ground are always connected. At this time, the DC500V voltage output is used to press the generator stator winding for 1 minute through the 1Y port, and the 15-second and 60-second insulation values ​​between the stator winding and the rotor winding are recorded at the same time. This cycle ends. Note: During the detection of each winding to the ground, when its insulation resistance drops to its set threshold (5MΩ) (this threshold can be set), relays KJ and KS act, and the corresponding insulation resistance display value flashes to alarm, and the panel alarm LED light is always on. Relay KJ is the start lock relay output, which allows the machine to start when it is normally closed. KS is the alarm relay output. When the generator fails, the KS contact changes from normally closed to normally open.

[0028] When the generator is in the startup state, the controller stops all the above measurements, and the generator running status LED on the instrument panel flashes green. The controller sends out the generator running information for the main control room to receive. The insulation values ​​detected by the controller are all displayed as 999.9MΩ. At this time, the manual command of winding discharge to ground is invalid.

[0029] When the generator is in shutdown state, the green LED light of the generator running status light set on the instrument panel does not display. The controller sends the generator shutdown status information for the main control room to receive. The controller starts the above 1 and 2 work processes. At this time, the manual command winding discharge command is valid.

[0030] When the instrument is in alarm state, the normally closed contact of relay KJ is disconnected and the motor cannot be turned on. Only after the alarm fault is eliminated and the contact of relay KJ is in normally closed state, the condition for starting the motor is met. The controller has the function of self-reset after fault elimination.

[0031] The biggest difference between the patented product of the present invention and other monitoring instruments is that it can simultaneously measure the three modes of insulation resistance of the wind generator online (the insulation resistance of the generator stator winding to the ground, the insulation resistance of the generator rotor winding to the ground, and the insulation resistance of the winding between the generator stator and rotor), and record and send the insulation resistance, absorption ratio parameters (R15s / R60s) and faults.

[0032] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, the patent owner may make various variations or modifications within the scope of the appended claims. As long as they do not exceed the protection scope described in the claims of the present invention, they should be within the protection scope of the present invention.

Claims

1. An online monitoring instrument for insulation resistance of a wind turbine generator, comprising a first detection voltage output port and a second detection voltage output port respectively connected to the stator winding and the rotor winding of the generator, characterized in that: The first detection voltage output port 1Y is connected to the first relay K1, the normally open contact of the first relay K1 is grounded, the normally closed contact of the first relay K1 is connected to one of the normally open contact and the normally closed contact of the third relay K3, the second detection voltage output port 2Y is connected to the second relay K2, the normally open contact of the second relay K2 is grounded, the normally closed contact of the second relay K2 is connected to the other of the normally open contact and the normally closed contact of the third relay K3, and the detection voltage is connected through the third relay K3; A first isolation resistor R1 is provided between the stator winding and the first detection voltage output port, a second isolation resistor R2 is provided between the rotor winding and the second detection voltage output port 2Y, and an instrument external relay K is also included for determining whether the motor is in the start / stop state; The terminals of the generator casing and the insulation resistance online monitor are connected to form a detection circuit. Four sets of dry yellow tube relays are set inside the insulation resistance online monitor. The discharge and charging actions of the generator winding to the ground are realized through software. The switch is made every 60 seconds to detect the insulation value of the stator winding and rotor winding of the generator to the ground and the insulation value between the stator winding and the rotor winding of the generator, and record the insulation absorption ratio parameters of the stator winding, rotor winding and between the stator winding and the rotor winding respectively to realize the measurement and alarm functions.

2. The wind turbine generator insulation resistance online monitoring instrument according to claim 1 is characterized in that: The detection voltage connected to the third relay K3 is a direct current of 500V.

3. The wind turbine generator insulation resistance online monitoring instrument according to claim 1, characterized in that: The first relay K1 , the second relay K2 and the third relay K3 are all reed switch relays.

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