CN212744207U - Multi-variable monitoring and protecting system for grid-connected loop of fan - Google Patents

Abstract

The utility model relates to a multi-variable monitoring and protecting system of a fan grid-connected loop, which comprises a main transformer, a box transformer main circuit breaker, a grid-connected contactor, a comprehensive protecting module, an anti-impact LVRT unit, a wheel capture energy side parallel speed measuring device, a wind wheel capture energy side protecting device, a safety chain and an intelligent analysis protecting system; the main transformer and the box transformer main circuit breaker are positioned in a box-type substation, an external power grid is connected with the main transformer through a wire, the main transformer is connected with the box transformer main circuit breaker, the box transformer main circuit breaker is connected with a grid-connected contactor, and the grid-connected contactor is connected with a generator in a wind driven generator cabin; the comprehensive protection module and the anti-impact LVRT unit are respectively connected with the grid-connected contactor, and the comprehensive protection module is also connected with the safety chain; this application combines two links of mechanical transmission and electrical control, forms the multilayer monitoring protection mechanism of unit running state, guarantees the unit safe operation comprehensively, avoids the unit accident of catching fire because of overspeed or electric elements trouble causes and takes place.

Description

Multi-variable monitoring and protecting system for grid-connected loop of fan

Technical Field

The utility model relates to a wind-powered electricity generation technical field, specifically say, relate to a fan is incorporated into power networks return circuit multivariable monitoring and protection system.

Background

Voltage Ride Through (LVRT) refers to when the voltage of the grid-connected point of the wind turbine drops, the wind turbine can keep being connected to the grid, even provide certain reactive power to the grid, and support the grid to recover until the grid recovers to normal, thereby "riding through" this low voltage time (area).

Wind farms are mostly located in remote areas with traffic congestion. In addition, the large grid-connected wind turbine generator is outdoor aerial operation equipment. Once a fire occurs, the difficulty of fighting is high, once the fire occurs, great direct loss is caused, and the possibility of external rescue is extremely low. The double-fed wind generating set has a large number of components and a complex and compact structure, so that the fire problem is particularly prominent. From the fire type, the wind turbine generator system relates to various materials such as lubricating grease, hydraulic oil, electrical equipment, wires and cables, blades, an engine room cover and an insulating layer thereof in the design and manufacturing processes, and the types of combustible materials are more. Therefore, the fire type of the unit is complicated and can be divided into an electrical fire, a solid fire and a liquid fire. The fire of the unit is caused by two reasons, namely that the main shaft bearing and the gear box grease oil are over-heated and ignited due to the overspeed of the rotation of the impeller, and grid-connected and ignited due to the damage of the control equipment of the generator. For example, patent publication No. CN 105162084B: a method for realizing electrical safety protection of a wind turbine generator carries out short-circuit protection of a high-voltage side and backup protection of a low-voltage side of the wind turbine generator through a target fuse, has the advantages of being simple in realization method, matched with electrical fault characteristics of the wind turbine generator in protection characteristics of electrical safety equipment, capable of realizing chain protection and high in electrical safety performance, does not monitor and protect a mechanical transmission side of the wind turbine generator, and cannot comprehensively protect safe operation of the wind turbine generator.

At present, the main fan fire problems at home and abroad mainly have the following defects: (1) a targeted research and solution for the root cause of the fire of the fan and corresponding emergency measures thereof is lacked; (2) specific fault characteristic parameters are extracted from two aspects of unit energy capture and electrical control to carry out real-time monitoring on the wind turbine; (3) the required cost is higher, the application is single, and the universality is poorer.

Therefore, it is necessary to design a system and a method for multivariate monitoring and protection of a fan grid-connected loop with complete functions and comprehensive system.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the above-mentioned not enough that exists among the prior art, and provide a reasonable in design, the perfect fan of system and grid-connected return circuit multivariable monitoring and protection system, use this system to carry out the action protection under the forecast diagnosis and the dangerous condition to the return circuit that is connected to the power networks to supporting intelligent fire extinguishing system is applied to wind turbine generator system, guarantees the unit safe operation, avoids the fire incident that the unit arouses because of speeding or the switch problem that is connected to the power networks.

The utility model provides a technical scheme that above-mentioned problem adopted is: a multivariable monitoring and protecting system of a fan grid-connected loop is characterized in that: the system comprises a main transformer, a box transformer main circuit breaker, a grid-connected contactor, a comprehensive protection module, an anti-impact LVRT unit, a wheel capture energy side parallel speed measuring device, a wind wheel capture energy side protection device, a safety chain and an intelligent analysis protection system; the main transformer and the box transformer main circuit breaker are positioned in a box-type substation, an external power grid is connected with the main transformer through a wire, the main transformer is connected with the box transformer main circuit breaker, the box transformer main circuit breaker is connected with a grid-connected contactor, and the grid-connected contactor is connected with a generator in a cabin of a wind driven generator; the comprehensive protection module and the anti-impact LVRT unit are respectively connected with a grid-connected contactor, and the comprehensive protection module is also connected with a safety chain;

the comprehensive protection module is used for selecting an action object and an action speed according to characteristic parameters of the grid-connected contactor, and breaking the grid-connected contactor or the box transformer main circuit breaker according to real-time breaking current and fault states through cooperation with the box transformer main circuit breaker, so that related devices are prevented from being damaged by using the grid-connected contactor under a large-current load working condition;

the anti-impact LVRT unit has the function of a circuit breaker, the anti-impact LVRT unit is used for simulating the function of the circuit breaker, and meanwhile, the low-penetration problem of the grid-connected contactor is solved under the condition that the capacity of external power distribution and a standby power supply is not changed; the circuit breaker is originally installed to the contactor that is incorporated into the power networks, and the circuit breaker among the contactor that will be incorporated into the power networks in this application is torn open, utilizes the function of protecting against shock LVRT unit replacement circuit breaker.

The intelligent analysis protection system directly controls a safety chain at the wind wheel catching side when the wind wheel rotating speed monitored by the wheel catching side parallel speed measuring device exceeds the rated rotating speed, skips a slip ring communication link, and enables the unit to be disconnected from the network and shut down in time;

the wind wheel energy capturing side protection device is arranged at the position of a cabin of the wind driven generator and is in communication connection with the intelligent analysis protection system, and the wind wheel energy capturing side protection device is used for sending a system abnormal signal to the intelligent analysis protection system under the condition that the electric control side element is damaged to cause the failure of the off-grid and when the unit is in an overspeed stage, so as to prevent the unit from overspeed accidents;

the intelligent analysis protection system is used for monitoring, recording, analyzing and protecting overvoltage, low voltage, unbalance, frequency abnormity, power abnormity, harmonic wave, short circuit and overspeed problems of a single unit of the power plant, and can provide data and theoretical support for problem search and subsequent optimization of equipment.

Preferably, the multi-variable monitoring and protecting system of the fan grid-connected loop further comprises an intelligent automatic fire-fighting device, wherein the intelligent automatic fire-fighting device is installed beside one side of the grid-connected contactor and externally connected with an aerosol fire-extinguishing device; the intelligent automatic fire fighting device is used for gas/smoke detection, temperature detection and flame detection; the intelligent automatic fire fighting device is in communication connection with the intelligent analysis protection system and is matched with the intelligent analysis protection system to carry out logic fault judgment, early warning and fire alarm; the intelligent automatic fire fighting device is matched with the action of the intelligent analysis protection system to eliminate the fire point at a fixed point; when the intelligent analysis protection system confirms that a large-current discharge state occurs, the intelligent analysis protection system sends a confirmation protection demand signal to the intelligent automatic fire fighting device, the intelligent analysis protection system immediately breaks the main circuit breaker of the box transformer substation, and the intelligent automatic fire fighting device automatically carries out fire fighting and extinguishment.

Preferably, the wheel-capture energy side parallel speed measuring device comprises a proximity switch, a signal isolator, a PLC (programmable logic controller) and a gyroscope; the proximity switch sets up a plurality of, and a plurality of proximity switch passes through the signal isolator and is connected with the PLC controller, the gyroscope is installed outside aerogenerator's wheel hub's hexagonal cabinet, and the gyroscope is connected with the PLC controller, the PLC controller still with safety chain communication connection.

Preferably, the wind turbine energy capturing side protection device comprises a striker, and the striker is mounted on a nacelle of the wind turbine generator.

Preferably, the multivariate monitoring and protecting system of the fan grid-connected loop further comprises a system redundancy protecting unit, wherein the system redundancy protecting unit is respectively in communication connection with the intelligent analysis protecting system, the grid-connected contactor and the safety chain; the system redundancy protection unit is used for respectively controlling the grid-connected contactor and the safety chain by judging the breaking current and the wind wheel rotating speed when the unit has an overspeed condition, so that the unit can be timely off-grid unloaded, and the complete equipment is ensured.

Preferably, the multivariate monitoring and protecting system of the fan grid-connected loop further comprises a remote state monitoring system, wherein the remote state monitoring system is in communication connection with the comprehensive protection module, the impact-proof LVRT unit, the wheel capture energy side parallel speed measuring device, the wind wheel capture energy side protecting device, the safety chain and the intelligent analysis protecting system respectively;

the remote state monitoring system is used for supporting remote real-time waveform recording and characteristic quantity calculation of monitoring personnel, system problem warning and backup protection, conventional grid-connected characteristic analysis, fault process transient and steady state analysis, whole power generation equipment correlation analysis, power generation field fault analysis and positioning and unit overspeed recording operation.

The utility model also provides a fan is incorporated into power networks circuit multivariable monitoring and protection method adopts foretell fan to be incorporated into power networks circuit multivariable monitoring and protection system and implements its characterized in that: the multivariable monitoring and protection method of the fan grid-connected loop combines an electrical control protection mechanism method and a mechanical transmission protection mechanism method;

the electric control protection mechanism method comprises the following steps:

firstly, an integrated protection module is utilized to select an action object and an action speed according to characteristic parameters of a grid-connected contactor, and the grid-connected contactor or a box transformer substation main circuit breaker is subjected to breaking according to real-time breaking current and fault states through cooperation with the box transformer substation main circuit breaker, so that the risk that related devices are damaged by using the grid-connected contactor to break a network under a large-current load working condition is avoided;

secondly, simulating the function of the original circuit breaker by using an anti-impact LVRT unit, and solving the problem of low penetration of a grid-connected contactor under the condition of not changing the capacity of external power distribution and a standby power supply;

thirdly, the intelligent analysis protection system can monitor, record, analyze and protect the problems of overvoltage, low voltage, unbalance, abnormal frequency, abnormal power, harmonic wave, short circuit and overspeed which occur to a single unit of the power plant, and can provide data and theoretical support for problem search and subsequent optimization of equipment; the intelligent analysis protection system can also judge the breaking grid-connected contactor or the previous stage protection circuit breaker through the breaking current real-time value when a frequency converter in the main control or grid-connected contactor of the unit sends a breaking grid-connected switch request, so that the circuit breaker and the contactor work in the most reasonable breaking state, the optimal service life is reached, and accidents are avoided; the intelligent analysis protection system simultaneously counts the breaking times of the grid-connected contactor and reminds the health condition of the equipment before the theoretical maximum service life is reached; the intelligent analysis protection system also monitors the change of the rotating speed of the wind wheel of the wind driven generator in real time, and in order to prevent the condition that the communication is out of synchronization caused by the damage of transmission equipment of a variable pitch control system, when the rotating speed exceeds the rated rotating speed, the intelligent analysis protection system directly controls a safety chain at the wind catching side of the wind wheel, skips a slip ring communication link, so that the unit is disconnected and stopped in time, and meanwhile, in the overspeed stage of the unit, in order to prevent the condition that the component at the electric control side is damaged and can not be disconnected, the control link at the wind wheel catching side can timely remedy the damage, so that the; in addition, the breaking protection requirement is built in, so that the actual use requirement of the wind generating set is met most, when serious problems occur in a grid-connected loop, such as a large unbalanced state, a serious negative power state and the like, the main control system is matched to complete the function of immediately breaking the main loop protection, and accidents are avoided;

the mechanical transmission protection mechanism method comprises the following steps:

the method is characterized in that a mode of combining a wheel capture energy side parallel speed measuring device and a wind wheel capture energy side protection device is adopted, the wheel capture energy side parallel speed measuring device is used for monitoring the change of the rotating speed of a wind wheel of a wind driven generator in real time, in order to prevent the condition that the communication is out of synchronization caused by the damage of transmission equipment of a variable pitch control system, when the rotating speed exceeds the rated rotating speed, an intelligent analysis protection system directly controls a safety chain at the wind wheel capture side, and a slip ring communication link is skipped, so that a unit is timely disconnected from a network; meanwhile, in order to prevent the condition that the electric control side element is damaged to cause the condition of incapability of being off-line, the wind wheel energy capturing side protection device sends out a system abnormal signal in the overspeed stage of the unit, so that the overspeed accident of the unit is prevented.

Compared with the prior art, the utility model, have following advantage and effect:

1. the utility model discloses a from two aspects of unit energy capturing aspect and electrical control aspect, research unit safe operation's under different operating condition actual demand, extract corresponding characteristic variable parameter, carry out the action protection under the prediction diagnosis and the dangerous condition to the circuit that is incorporated into the power networks through intelligent analysis protection system to supporting intelligent fire extinguishing system is applied to wind turbine generator system, guarantees unit safe operation, avoids the fire accident that the unit arouses because of overspeed or the switch problem that is incorporated into the power networks;

2. the utility model, through deep theoretical research on the fire accident problem of the wind turbine generator, combines two links of mechanical transmission and electrical control to form a multilayer monitoring protection mechanism of the running state of the generator, and is provided with an automatic fire fighting device corresponding to the mechanism, thereby comprehensively ensuring the safe running of the generator and avoiding the occurrence of the fire accident of the generator caused by overspeed or electrical element failure;

3. the utility model discloses can make the switch that is incorporated into the power networks be in its breaking capacity always and require work in the within range, avoid the fan because of the risk of starting a fire that the contactor problem that is incorporated into the power networks leads to. Meanwhile, the fault diagnosis information quantity is increased, the fault diagnosis system has the function of monitoring faults, can monitor, record, analyze and protect the overvoltage, low voltage, unbalance, frequency abnormity, power problems, harmonic waves and short circuit problems, provides data and theoretical support for problem search and subsequent optimization of equipment, improves the working pertinence of a wind power plant, and improves the reliable operation capacity of the equipment. Therefore, the reliability and flexibility of on-line monitoring of the fan can be improved, the method is a novel monitoring protection method, and the fireproof safety and stability of the fan are further improved.

Drawings

In order to illustrate the embodiments of the present invention or the solutions in the prior art more clearly, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Description of reference numerals: the transformer substation comprises a main transformer 1, a box transformer main circuit breaker 2, a grid-connected contactor 3, a comprehensive protection module 4, an anti-impact LVRT unit 5, a safety chain 6, a proximity switch 7, a signal isolator 8, a PLC (programmable logic controller) 9, a gyroscope 10, a striker 11 and a generator 12.

Detailed Description

The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not intended to limit the present invention.

Examples are given.

At present, the main reasons causing the wind driven generator to catch fire are grid-connected device damage and overspeed runaway:

damage of grid-connected devices:

the double-fed wind generating set usually selects a circuit breaker or a contactor as a grid-connected switch, but the performances of the double-fed wind generating set are respectively good and bad: the breaker has strong breaking capacity but limited service life and needs to be replaced frequently; the contactor has long service life, but the breaking capacity is weak, so that sometimes the running state of the unit cannot be accurately judged, and the off-line failure is caused. At present, most double-fed units use a contactor as a grid-connected switch, but due to the poor arc extinguishing capability and the easy occurrence of the problems of element aging and the like, the off-grid action of the units cannot be accurately executed sometimes. Meanwhile, electric shock adhesion, arc discharge and other phenomena are caused, so that the wind driven generator is on fire;

overspeed runaway:

in order to ensure the safe operation of the wind turbine generator, two levels of safety chain protection are generally provided. And the second safety chain is vertically butted with the variable pitch system. When the wind speed is higher than the cut-out wind speed of the unit or the rotating speed of the wind wheel exceeds the rated rotating speed, the second safety chain of the unit is disconnected, and the blades execute feathering action to prevent the unit from overspeed. However, the whole control link involves a plurality of devices such as sensors, slip rings, communication lines and the like, and any device has a fault, which may cause that the overspeed control process cannot be realized, so that the unit has a 'runaway' condition. In severe cases, grease of the main shaft bearing can be overheated, and a unit fire is caused.

The embodiment of the invention discloses a multivariable monitoring and protecting system of a fan grid-connected loop, and aims to improve the reliability of fire prediction and diagnosis of a doubly-fed wind generating set.

Referring to fig. 1, the wind turbine grid-connected loop multivariable monitoring and protection system comprises a main transformer 1, a box transformer main circuit breaker 2, a grid-connected contactor 3, a comprehensive protection module 4, an impact-proof LVRT unit 5, a wheel capture energy side parallel speed measuring device, a wind wheel capture energy side protection device, a safety chain 6, an intelligent analysis protection system, an intelligent automatic fire fighting device, a system redundancy protection unit and a remote state monitoring system.

In the embodiment, a main transformer 1 and a box transformer main circuit breaker 2 are positioned in a box-type substation, an external power grid is connected with the main transformer 1 through an electric wire, the main transformer 1 is connected with the box transformer main circuit breaker 2, the box transformer main circuit breaker 2 is connected with a grid-connected contactor 3, and the grid-connected contactor 3 is connected with a generator 12 in a cabin of a wind driven generator; the comprehensive protection module 4 and the anti-impact LVRT unit 5 are respectively connected with the grid-connected contactor 3, and the comprehensive protection module 4 is also connected with the safety chain 6.

In this embodiment, the comprehensive protection module 4 is configured to select an action object and an action speed according to the characteristic parameters of the grid-connected contactor 3, and through cooperation with the main box-to-substation circuit breaker, break the grid-connected contactor 3 or the main box-to-substation circuit breaker according to a real-time breaking current and a fault state, so as to avoid using the grid-connected contactor 3 to break a network under a large-current load condition and damage related devices.

In this embodiment, the anti-shock LVRT unit 5 has a function of a circuit breaker, and solves the problem of low-voltage breakdown of the grid-connected contactor 3 without changing the capacity of the external power distribution and the backup power supply.

In the embodiment, the wheel capture energy side parallel speed measuring device is installed at the hub position of the wind driven generator and used for monitoring the change of the rotating speed of the wind wheel of the wind driven generator in real time, the wheel capture energy side parallel speed measuring device is in communication connection with the intelligent analysis and protection system, and when the rotating speed of the wind wheel monitored by the wheel capture energy side parallel speed measuring device exceeds the rated rotating speed, the intelligent analysis and protection system directly controls the safety chain 6 at the wind wheel capture side, skips a slip ring communication link, and enables the unit to be shut down in a timely off-line mode. Specifically, the wheel capture energy side parallel speed measuring device comprises a proximity switch 7, a signal isolator 8, a PLC (programmable logic controller) 9 and a gyroscope 10. Proximity switch 7 sets up threely, and three proximity switch 7 passes through signal isolator 8 to be connected with PLC controller 9, and outside the hexagonal cabinet of aerogenerator's wheel hub was installed to gyroscope 10, gyroscope 10 was connected with PLC controller 9, and PLC controller 9 still with safety chain 6 communication connection.

In this embodiment, the wheel capture energy side parallel speed measurement device adopts a parallel speed measurement mechanism of the proximity switch 7 and the gyroscope 10; the speed measurement mechanism for the proximity switch 7 and the gyroscope 10 is parallel to the speed measurement mechanism for the proximity switch 7 and the gyroscope 10. The speed measuring mechanism of the proximity switch 7 is that the proximity switch 7 accesses a detected pulse electric signal into the PLC 9, when a certain path of signal exceeds a preset alarm value, the fan system enters an alarm state, when the rest two channels are kept unchanged for a certain time, an alarm signal is output, the safety chain 6 is cut off, and the fan system is controlled to execute feathering action. The gyroscope 10 speed measurement mechanism is that the gyroscope 10 is installed outside the hexagonal cabinet of wheel hub, and when the gyroscope 10 measuring result surpassed the early warning value and lasted for a certain time and kept unchangeable, disconnection safety chain 6, control fan system execution feathering action.

In this embodiment, the wind wheel energy capturing side protection device is installed at a position of an engine room of the wind driven generator, the wind wheel energy capturing side protection device is in communication connection with the intelligent analysis protection system, and the wind wheel energy capturing side protection device is used for sending a system abnormal signal to the intelligent analysis protection system under the condition that the electric control side element is damaged to cause the failure of grid disconnection and when the unit is in an overspeed stage, so as to prevent the unit from overspeed accidents. Specifically, the wind turbine energy capturing side protection device includes a striker 11, and the striker 11 is mounted on a nacelle of the wind turbine generator. In the wind wheel energy capturing side protection device, the impact iron 11 is easy to collide with the proximity switch 7 when the wind wheel has relative displacement. When the proximity switch 7 breaks down, the three switch speeds are abnormal, the overspeed protection system cannot stop working at the moment, the gyroscope 10 is used for measuring the rotating speed, and the protection system can send out a system abnormal signal at the moment.

In this embodiment, the intelligent analysis protection system is used for monitoring, recording, analyzing and protecting overvoltage, low voltage, imbalance, frequency abnormality, power abnormality, harmonic, short circuit and overspeed problems of a single unit of the power plant, and can provide data and theoretical support for problem finding and subsequent optimization of equipment. The intelligent analysis protection system also has the following functions: 1) the historical data of the fan is analyzed, the parameter requirements of related equipment for controlling the disconnection and connection of the unit are simulated by matching with the anti-impact LVRT unit 5, the most reasonable disconnection current is calculated when the service lives of the contactor and the circuit breaker and the overspeed trip rotating speed of the unit are met, when the current exceeds a certain value, the main circuit breaker of the box-type substation is disconnected, and when the current is lower than the value, the disconnection and connection of the grid contactor 3 is disconnected; 2) and analyzing historical fault data to confirm the protection conditions of the off-line intelligent protection system, wherein the protection conditions at least comprise rated rotating speed of a wind wheel, limit rotating speed of the wind wheel, three-phase current unbalance and negative power.

In the embodiment, the intelligent automatic fire fighting device is arranged beside one side of the grid-connected contactor 3, and is externally connected with an aerosol fire extinguishing device; the intelligent automatic fire fighting device is used for gas/smoke detection, temperature detection and flame detection; the intelligent automatic fire fighting device is in communication connection with the intelligent analysis protection system and is matched with the intelligent analysis protection system to carry out logic fault judgment, early warning and fire alarm; the intelligent automatic fire fighting device is matched with the action of the intelligent analysis protection system to eliminate the fire point at a fixed point; when the intelligent analysis protection system confirms that a large-current discharge state occurs, the intelligent analysis protection system sends a confirmation protection demand signal to the intelligent automatic fire fighting device, the intelligent analysis protection system immediately breaks the main circuit breaker of the box transformer substation, and the intelligent automatic fire fighting device automatically carries out fire fighting and extinguishment.

In the embodiment, the system redundancy protection unit is respectively in communication connection with the intelligent analysis protection system, the grid-connected contactor 3 and the safety chain 6; the system redundancy protection unit is used for respectively controlling the grid-connected contactor 3 and the safety chain 6 by judging the breaking current and the wind wheel rotating speed when the unit has an overspeed condition, so that the unit can be off-grid and unloaded in time, and the complete equipment is ensured.

In this embodiment, the remote status monitoring system is in communication connection with the comprehensive protection module 4, the impact prevention LVRT unit 5, the parallel speed measurement device on the energy capturing side of the wheel, the protection device on the energy capturing side of the wind wheel, the safety chain 6 and the intelligent analysis protection system, respectively. The remote state monitoring system is used for supporting remote real-time waveform recording and characteristic quantity calculation of monitoring personnel, system problem warning and backup protection, conventional grid-connected characteristic analysis, fault process transient and steady state analysis, whole power generation equipment correlation analysis, power generation field fault analysis and positioning and unit overspeed recording operation.

The utility model also provides a fan is incorporated into power networks return circuit multivariable monitoring and protection method adopts foretell fan to be incorporated into power networks return circuit multivariable monitoring and protection system to implement, and fan is incorporated into power networks return circuit multivariable monitoring and protection method and adopts electrical control protection mechanism method and mechanical transmission protection mechanism method to combine together.

Considering that the doubly-fed wind generator has three rotating speeds, namely a stator synchronous rotating speed n, a rotor rotating speed n1 and a rotor electromagnetic rotating speed n 2. The generator set adjusts the rotor converter by calculating the slip ratio, adjusts the frequency and amplitude of the exciting current, ensures that the sum of the rotor electromagnetic rotating speed n2 and the real-time rotor rotating speed n1 is equal to the synchronous rotating speed n, thereby ensuring the power frequency working pressure at the stator side, and directly connecting the stator of the generator with the power grid through a grid-connected switch. The stator grid-tie switch generally uses a contactor or a circuit breaker. And under the working condition that the wind speed exceeds the minimum starting wind speed, the doubly-fed wind generating set expands the blades through the variable pitch system to absorb wind energy, when the rotating speed of the generator reaches the minimum grid-connected requirement, a frequency converter loop is precharged, then a grid-side contactor is closed, after the frequency converter continues to run to a synchronous state, the detected frequency, voltage and phase meet the grid-connected requirement, and then a stator grid-connected switch is closed. The unit safety chain is in a power-on state, and the variable pitch controller and the generator controller do not act on the safety chain.

Therefore, the protection mechanism combines two links of a mechanical transmission protection mechanism and an electrical control protection mechanism to form a multilayer monitoring protection mechanism of the unit running state, and is provided with an automatic fire fighting device corresponding to the protection mechanism, so that the safe running of the unit is comprehensively guaranteed, and the occurrence of unit fire accidents caused by overspeed or electrical element faults is avoided.

The design background of the electric control protection mechanism is as follows: in a generator grid connection link, a double-fed wind generating set generally selects a contactor or a circuit breaker as a grid connection switch. The main working components of the alternating current contactor are a low-voltage coil and an armature, after the coil wound on an iron core is electrified, electromagnetic induction is generated, a moving contact is attracted, the contactor is closed, the arc extinguishing capability of the alternating current contactor is weak, and the breaking current is generally only thousands of A. The electrical life of the contactor can generally reach dozens of thousands of times. Generally, after the temperature of the contactor is higher than 60 ℃, the capacity reduction condition at high temperature can occur, and the capacity and the service life can be influenced. The circuit breaker is also called an automatic switch, and is an electric appliance which not only has the function of a manual switch, but also can automatically perform voltage loss, undervoltage, overload and short-circuit protection. It can be used to protect power supply circuit and motor, and can automatically cut off circuit when serious overload or short circuit and under-voltage faults occur. The circuit breaker realizes rapid closing and breaking by a mechanical structure, has strong arc extinguishing capability, and can generally break current up to tens of thousands A. The relay protection can realize the functions of short delay protection, long delay protection, instantaneous interruption protection and the like, but the electrical service life is only thousands of times.

Therefore, the service life of the grid-connected contactor is prolonged by a comprehensive judgment mode combining software and hardware algorithms, and the electric control protection mechanism method comprises the following steps:

firstly, the comprehensive protection module 4 is used for selecting an action object and an action speed according to characteristic parameters of the grid-connected contactor 3, and breaking the grid-connected contactor 3 or the box transformer main breaker according to real-time breaking current and fault states through cooperation with the box transformer main breaker, so that the risk that related devices are damaged by using the grid-connected contactor 3 to break a network under a large-current load working condition is avoided;

secondly, simulating the function of the original circuit breaker by using the anti-impact LVRT unit 5, and solving the low-penetration problem of the grid-connected contactor 3 under the condition of not changing the capacity of external power distribution and a standby power supply;

thirdly, the intelligent analysis protection system can monitor, record, analyze and protect the problems of overvoltage, low voltage, unbalance, abnormal frequency, abnormal power, harmonic wave, short circuit and overspeed which occur to a single unit of the power plant, and can provide data and theoretical support for problem search and subsequent optimization of equipment; the intelligent analysis protection system can also judge the breaking grid-connected contactor 3 or the previous stage protection circuit breaker through the breaking current real-time value when the frequency converter in the main control or grid-connected contactor 3 of the unit sends a breaking grid-connected switch requirement, so that the circuit breaker and the contactor work in the most reasonable breaking state, the optimal service life is reached, and accidents are avoided; the intelligent analysis protection system simultaneously counts the breaking times of the grid-connected contactor 3, and reminds the health condition of the equipment before the theoretical maximum service life is reached; the intelligent analysis protection system also monitors the change of the rotating speed of the wind wheel of the wind driven generator in real time, and in order to prevent the condition that the communication is out of synchronization caused by the damage of transmission equipment of a variable pitch control system, when the rotating speed exceeds the rated rotating speed, the intelligent analysis protection system directly controls a safety chain at the wind catching side of the wind wheel, skips a slip ring communication link, so that the unit is disconnected and stopped in time, and meanwhile, in the overspeed stage of the unit, in order to prevent the condition that the component at the electric control side is damaged and can not be disconnected, the control link at the wind wheel catching side can timely remedy the damage, so that the; in addition, the breaking protection requirement is built in, so that the actual use requirement of the wind generating set is met best, when serious problems occur in the grid-connected loop, such as a large unbalanced state, a serious negative power state and the like, the main control system is matched to complete the function of immediately breaking the main loop protection, and accidents are avoided.

The design background of the mechanical transmission protection mechanism is as follows: the wind turbine generator pitch control system is relatively independent from other systems of the generator set in terms of control logic or installation position. The variable pitch system has a complete logic judgment and equipment state analysis function system and is vertically associated with the main control of the unit in a communication, circuit and safety chain mode. Influenced by the design link of the wind turbine generator, when the variable pitch system operates normally, the wind turbine generator cannot overspeed normally. Therefore, most wind turbine generators are not equipped with an impeller overspeed alarm function. Instead, the rotation speed threshold is set manually simply by detecting the rotation speed of the main shaft or the impeller. And when the rotating speed of the main shaft exceeds a threshold value, finishing the feathering action by controlling the pitch control system through the master control. However, in practical applications it is found that: communication and control functions are not realized due to sensor faults, slip ring faults or virtual connection of communication lines and the like. These problems all can lead to the unit to appear the overspeed phenomenon, can cause the catastrophic accident such as main shaft bearing carbonization, fire in the serious time.

Therefore, the mechanical transmission protection mechanism method combining the wheel energy capturing side parallel speed measuring device and the wind wheel energy capturing side protection device is adopted. The mechanical transmission protection mechanism method comprises the following steps: the method is characterized in that a mode of combining a wheel capture energy side parallel speed measuring device and a wind wheel capture energy side protection device is adopted, the wheel capture energy side parallel speed measuring device is used for monitoring the change of the rotating speed of a wind wheel of a wind driven generator in real time, in order to prevent the condition that the communication is out of synchronization caused by the damage of transmission equipment of a variable pitch control system, when the rotating speed exceeds the rated rotating speed, an intelligent analysis protection system directly controls a safety chain 6 at the wind wheel capture side, a slip ring communication link is skipped, and the unit is timely disconnected from the network and shut; meanwhile, in order to prevent the condition that the electric control side element is damaged to cause the condition of incapability of being off-line, the wind wheel energy capturing side protection device sends out a system abnormal signal in the overspeed stage of the unit, so that the overspeed accident of the unit is prevented.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an example of the structure of the present invention. All the equivalent changes or simple changes made according to the structure, characteristics and principle of the patent idea of the utility model are included in the protection scope of the patent of the utility model. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims (6)

1. A multivariable monitoring and protecting system of a fan grid-connected loop is characterized in that: the wind wheel energy capturing system comprises a main transformer (1), a box transformer main circuit breaker (2), a grid-connected contactor (3), a comprehensive protection module (4), an anti-impact LVRT unit (5), a wheel energy capturing side parallel speed measuring device, a wind wheel energy capturing side protection device, a safety chain (6) and an intelligent analysis protection system;

the main transformer (1) and the box transformer main circuit breaker (2) are located in a box-type substation, an external power grid is connected with the main transformer (1) through a wire, the main transformer (1) is connected with the box transformer main circuit breaker (2), the box transformer main circuit breaker (2) is connected with a grid-connected contactor (3), and the grid-connected contactor (3) is connected with a generator (12) in a wind driven generator cabin; the comprehensive protection module (4) and the anti-impact LVRT unit (5) are respectively connected with the grid-connected contactor (3), and the comprehensive protection module (4) is also connected with the safety chain (6);

the comprehensive protection module (4) is used for selecting an action object and an action speed according to characteristic parameters of the grid-connected contactor (3), and breaking the grid-connected contactor (3) or the box-type substation main breaker (2) according to real-time breaking current and fault states through cooperation with the box-type substation main breaker (2), so that related devices are prevented from being damaged by using the grid-connected contactor (3) in a grid-off mode under a large-current loading condition;

the anti-impact LVRT unit (5) has the function of a circuit breaker, the anti-impact LVRT unit (5) is used for simulating the function of the circuit breaker, and meanwhile the low-penetration problem of the grid-connected contactor (3) is solved under the condition that the capacity of external power distribution and a standby power supply is not changed;

the intelligent analysis protection system directly controls a safety chain at the wind wheel catching side when the wind wheel rotating speed monitored by the wheel catching side parallel speed measuring device exceeds the rated rotating speed, skips a slip ring communication link, and enables the unit to be disconnected from the network and shut down in time;

the wind wheel energy capturing side protection device is arranged at the position of a cabin of the wind driven generator and is in communication connection with the intelligent analysis protection system, and the wind wheel energy capturing side protection device is used for sending a system abnormal signal to the intelligent analysis protection system under the condition that the electric control side element is damaged to cause the failure of the off-grid and when the unit is in an overspeed stage, so as to prevent the unit from overspeed accidents;

the intelligent analysis protection system is used for monitoring, recording, analyzing and protecting overvoltage, low voltage, unbalance, frequency abnormity, power abnormity, harmonic wave, short circuit and overspeed problems of a single unit of the power plant, and can provide data and theoretical support for problem search and subsequent optimization of equipment.

2. The multivariate monitoring and protecting system of a wind turbine grid-connected loop according to claim 1, characterized in that: the multi-variable monitoring and protecting system of the fan grid-connected loop further comprises an intelligent automatic fire-fighting device, wherein the intelligent automatic fire-fighting device is arranged beside one side of the grid-connected contactor (3), and is externally connected with an aerosol fire-extinguishing device; the intelligent automatic fire fighting device is used for gas/smoke detection, temperature detection and flame detection; the intelligent automatic fire fighting device is in communication connection with the intelligent analysis protection system and is matched with the intelligent analysis protection system to carry out logic fault judgment, early warning and fire alarm; the intelligent automatic fire fighting device is matched with the action of the intelligent analysis protection system to eliminate the fire point at a fixed point; when the intelligent analysis protection system confirms that a large-current discharge state occurs, the intelligent analysis protection system sends a confirmation protection demand signal to the intelligent automatic fire fighting device, the intelligent analysis protection system immediately breaks the main circuit breaker (2) of the box transformer substation, and the intelligent automatic fire fighting device carries out automatic fire fighting and extinguishment.

3. The multivariate monitoring and protecting system of a wind turbine grid-connected loop according to claim 1, characterized in that: the wheel-capture energy side parallel speed measuring device comprises a proximity switch (7), a signal isolator (8), a PLC (programmable logic controller) controller (9) and a gyroscope (10); proximity switch (7) set up a plurality of, and a plurality of proximity switch (7) pass through signal isolator (8) and are connected with PLC controller (9), install outside aerogenerator's wheel hub's hexagonal cabinet gyroscope (10), gyroscope (10) are connected with PLC controller (9), PLC controller (9) still with safety chain (6) communication connection.

4. The multivariate monitoring and protecting system of a wind turbine grid-connected loop according to claim 1, characterized in that: the wind wheel energy capturing side protection device comprises a collision iron (11), and the collision iron (11) is installed on a cabin of the wind driven generator.

5. The multivariate monitoring and protecting system of a wind turbine grid-connected loop according to claim 1, characterized in that: the multivariable monitoring and protecting system of the fan grid-connected loop further comprises a system redundancy protecting unit, wherein the system redundancy protecting unit is in communication connection with the intelligent analysis protecting system, the grid-connected contactor (3) and the safety chain (6) respectively; the system redundancy protection unit is used for respectively controlling the grid-connected contactor (3) and the safety chain (6) by judging the breaking current and the wind wheel rotating speed when the unit has an overspeed condition, so that the unit can be timely off-grid and unloaded, and the complete equipment is ensured.

6. The multivariate monitoring and protecting system of a wind turbine grid-connected loop according to claim 1, characterized in that: the multivariable monitoring and protecting system of the fan grid-connected loop further comprises a remote state monitoring system, wherein the remote state monitoring system is respectively in communication connection with the comprehensive protection module (4), the impact-proof LVRT unit (5), the wheel capture energy side parallel speed measuring device, the wind wheel capture energy side protecting device, the safety chain (6) and the intelligent analysis protecting system;

the remote state monitoring system is used for supporting remote real-time waveform recording and characteristic quantity calculation of monitoring personnel, system problem warning and backup protection, conventional grid-connected characteristic analysis, fault process transient and steady state analysis, whole power generation equipment correlation analysis, power generation field fault analysis and positioning and unit overspeed recording operation.

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