CN116412066A

CN116412066A - Hydraulic variable pitch safety chain of wind generating set and wind generating set

Info

Publication number: CN116412066A
Application number: CN202111635622.8A
Authority: CN
Inventors: 陈明明; 汪萍萍; 单秀清
Original assignee: Xinjiang Goldwind Science and Technology Co Ltd
Current assignee: Xinjiang Goldwind Science and Technology Co Ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2023-07-11

Abstract

A hydraulic variable pitch safety chain of a wind generating set and the wind generating set are disclosed. The hydraulic pitch safety chain comprises: the emergency stop button, the safety relay, the variable pitch controller, the contactor, the switching power supply, the lightning protection module of the variable pitch system power supply and the plurality of fault nodes; the fault nodes comprise emergency stop button auxiliary contacts, a main control safety chain OK signal node, an energy storage pressure switch, a pitch control system OK signal node, a switching power supply OK signal node and a lightning protection signal node, and are connected to the input end of the safety relay in series; the coil of the contactor is connected with the auxiliary contact of the safety relay, and the main contact of the contactor is connected in series between the solenoid valve coil of the solenoid valve group for controlling the hydraulic pitch actuator and the power supply; when any fault node is triggered, the safety relay acts to cut off the power supply of the coil of the contactor, so that the power supply of the electromagnetic valve coil of the electromagnetic valve group of the pitch actuator is cut off, and the wind generating set executes feathering.

Description

Hydraulic variable pitch safety chain of wind generating set and wind generating set

Technical Field

The invention relates to the field of wind power generation control. And more particularly, to a hydraulic pitch safety chain of a wind turbine generator system and a wind turbine generator system including the hydraulic pitch safety chain.

Background

The pitch system is an important component of a wind power generator set, which enables the wind power generator set to obtain maximum wind energy by controlling the position of the pitch angle of the blades. The variable pitch safety chain is the last defense line under the condition of failure of the software protection system, and once the variable pitch safety chain is triggered, the blades of the wind generating set can execute emergency feathering, so that safe and reliable shutdown of the wind generating set is realized.

The main variable pitch control technology of the wind generating set is divided into an electric variable pitch control technology and a hydraulic variable pitch control technology, wherein the electric variable pitch system adopts a driving motor to control the blades in cooperation with a speed reducer, and has the advantages of high response speed, compact structure and reliability, but the electric control device is high in price. With the development of wind power generation technology and the increase of unit capacity, hydraulic pitch technology has been favored by wind power generation developers and owners due to the characteristics of small volume, light weight, quick dynamic response, high precision, large driving force, high reliability, no need of a speed change mechanism, mature technology and the like. In addition, as the capacity of the unit is increased, the diameter of the impeller is also increased, and the conventional electric pitch technology is difficult to drive the impeller with such large pitch while ensuring the action reliability, and particularly in the offshore unit, the maintenance is inconvenient and the requirement on the pitch reliability is very high.

Thus, there is a need for a safety chain system suitable for hydraulic pitch.

Disclosure of Invention

The invention aims to provide a hydraulic pitch control safety chain of a wind power generator unit and the wind power generator unit, and the safety and reliability of a hydraulic pitch control system are further improved by using the redundant design of contactors and monitoring the running state of a pitch control device.

An aspect of the present invention provides a hydraulic pitch safety chain of a wind turbine generator system, the hydraulic pitch safety chain comprising: the emergency stop button, the safety relay, the variable pitch controller, the contactor, the switching power supply, the lightning protection module of the variable pitch system power supply and the plurality of fault nodes; the fault nodes comprise emergency stop button auxiliary contacts, a main control safety chain OK signal node, an energy storage pressure switch, a pitch control system OK signal node, a switching power supply OK signal node and a lightning protection signal node, and are connected to the input end of the safety relay in series; the coil of the contactor is connected with the auxiliary contact of the safety relay, and the main contact of the contactor is connected in series between the solenoid valve coil of the solenoid valve group for controlling the hydraulic pitch actuator and a power supply; when any fault node is triggered, the safety relay acts to cut off the power supply of the coil of the contactor, so that the power supply of the electromagnetic valve coil of the electromagnetic valve group of the pitch actuator is cut off, and the wind generating set executes feathering.

Optionally, the contactor may include a first contactor and a second contactor; the coil anode of the first contactor is connected to the anode of the switching power supply through the auxiliary contact of the first output channel of the safety relay, and the coil cathode of the first contactor is connected to the cathode of the switching power supply; the coil positive pole of the second contactor is connected to the positive pole of the switching power supply via the auxiliary contact of the second output channel of the safety relay, and the coil negative pole of the second contactor is connected to the negative pole of the switching power supply.

Optionally, the first normally open main contact of the first contactor and the second normally open main contact of the second contactor may be connected in series between a solenoid valve coil of a solenoid valve group of the pitch actuator and a power supply, wherein when the safety relay acts, an auxiliary contact of each output channel of the safety relay is disconnected to cut off the power supply of the coil of the contactor.

Alternatively, the first normally open main contact of the first contactor and the second normally open main contact of the second contactor may be connected in series between the coil of the control relay and the power supply, and the normally open contacts of the control relay are connected in series to the pitch proportional valve input voltage signal loop, wherein the pitch proportional valve input voltage signal is 0V when the safety relay is operated.

Optionally, the hydraulic pitch safety chain may further include a delay relay for monitoring a pulse signal output by the pitch controller, and contacts of the delay relay are connected in series in the plurality of fault nodes.

Alternatively, the delay relay may include an energizing delay relay and a de-energizing delay relay, the coils of the energizing delay relay and the de-energizing delay relay being connected in parallel, and the coils of the energizing delay relay and the de-energizing delay relay receiving the pulse signal output by the pitch controller as the power supply signal; wherein a delay setting value of the delay relay is associated with a high level duration and a low level duration of the pulse signal.

Alternatively, the delay relay contact may include a normally closed contact of an energized delay relay and a normally open contact of a de-energized delay relay, the normally closed contact and the normally open contact being connected in series in the plurality of fault nodes.

Alternatively, the emergency stop button auxiliary contacts may comprise two emergency stop button auxiliary contacts of an emergency stop button of the pitch control cabinet, and the two emergency stop button auxiliary contacts are connected in parallel.

Alternatively, the stored pressure switch may be closed when the accumulator pressure is above a threshold value, and open when the accumulator pressure is below the threshold value.

Another aspect of the invention provides a wind power plant comprising a hydraulic pitch safety chain comprising: the emergency stop button, the safety relay, the variable pitch controller, the contactor, the switching power supply, the lightning protection module of the variable pitch system power supply and the plurality of fault nodes; the fault nodes comprise emergency stop button auxiliary contacts, a main control safety chain OK signal node, an energy storage pressure switch, a pitch control system OK signal node, a switching power supply OK signal node and a lightning protection signal node, and are connected to the input end of the safety relay in series; the coil of the contactor is connected with the auxiliary contact of the safety relay, and the main contact of the contactor is connected in series between the solenoid valve coil of the solenoid valve group for controlling the hydraulic pitch actuator and a power supply; when any fault node is triggered, the safety relay acts to cut off the power supply of the coil of the contactor, so that the power supply of the electromagnetic valve coil of the electromagnetic valve group of the pitch actuator is cut off, and the wind generating set executes feathering.

According to the hydraulic pitch safety chain of the wind generating set and the wind generating set, through redundant design of the auxiliary contacts and the contactors of the safety relay in the pitch safety chain control loop, when any fault node in the pitch safety chain loop is triggered, the power supply of the electromagnetic valve coil of the electromagnetic valve group of the hydraulic pitch actuator can be ensured to be cut off. In addition, the pulse signal output by the variable-pitch controller is used as an input signal of the delay relay, and the auxiliary contact of the delay relay is connected in series into the safety chain loop, so that abnormal running states such as communication loss, blocking, breakdown and the like of the variable-pitch controller can be monitored, and the safety and reliability of the hydraulic variable-pitch system are guaranteed to the greatest extent.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagram illustrating an example of a hydraulic pitch safety chain of a wind turbine according to some example embodiments;

FIG. 2 is a diagram illustrating an example of a time delay relay according to some example embodiments;

fig. 3 is a diagram illustrating an example of a hydraulic pitch actuator according to some example embodiments.

Detailed Description

Embodiments of the present invention are described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating an example of a hydraulic pitch safety chain of a wind turbine generator system according to some example embodiments.

Different from an electric pitch control system, the hydraulic pitch control system takes an electric hydraulic pump as working power, hydraulic oil as a transmission medium and an electromagnetic valve as a control unit, and changes radial movement of a piston rod of an oil cylinder into circular movement of a blade to realize pitch control. The hydraulic pitch control system consists of a signal given component, an actuating mechanism, a proportional valve, a displacement/pressure sensor, a feedback signal and the like. The hydraulic pitch safety chain consists of key component nodes in hydraulic pitch according to the hydraulic principle.

Referring to fig. 1, a hydraulic pitch safety chain according to an example embodiment of the present disclosure includes: scram button EB, safety relay J1, pitch controller (not shown), contactors (e.g., KM1 and KM 2), switching power supply (e.g., 24V Direct Current (DC) switching power supply), pitch system power lightning protection module (not shown), delay relay (not shown), and a plurality of fault nodes K11-K17. A plurality of fault nodes K11 to K17 are connected in series to a safety relay J1 to constitute a hydraulic pitch safety chain circuit.

Referring to fig. 1, the plurality of failed nodes includes: the emergency stop button auxiliary contact K11, the main control safety chain OK signal node K12, the energy storage pressure switch K13, the delay relay contact K14, the pitch system OK signal node K15, the switching power supply OK signal node K16 and the lightning protection signal node K17.

The safety relay is a core component of the safety chain and is also an actuating mechanism of the safety chain. A plurality of fault nodes may be connected in series to an input channel (or input) of a safety relay to form a hydraulic pitch safety chain circuit. Referring to fig. 1, a plurality of fault nodes are connected in series between input terminals S10 and S11 of the safety relay.

The auxiliary contact of the output channel (or output end) of the safety relay can be connected with a coil of a contactor of an electromagnetic valve bank of a hydraulic pitch actuator of the wind generating set, and the main contact of the contactor is connected in series between the electromagnetic valve coil of the electromagnetic valve bank and a power supply. When any one or more fault nodes are triggered, the hydraulic pitch safety chain circuit is disconnected, the safety relay acts to cut off the power supply of the coil of the contactor, so that the electromagnetic valve group (described in the following figure 3) of the hydraulic pitch actuator is disconnected, and the wind generating set performs emergency feathering action, so that the wind generating set is ensured to be safely stopped.

In order to improve the reliability of the hydraulic pitch-control safety chain, the redundant design of auxiliary contacts of the contactor and the safety relay can ensure that the power supply of the electromagnetic valve coil of the electromagnetic valve group of the hydraulic pitch-control actuator can be reliably cut off when the safety relay acts, so that the emergency feathering of the wind generating set is realized.

Referring to fig. 1, the safety relay J1 may include two output channels, a first output channel corresponding to the

terminals

13 and 14 and a second output channel corresponding to the

terminals

23 and 24. Under normal conditions, the auxiliary contacts between

terminals

13 and 14 and between

terminals

23 and 24 are in a closed state. When the safety relay J1 is actuated, the auxiliary contacts between the

terminals

13 and 14 and between the

terminals

23 and 24 are in an open state. Further, a reset signal RS may be input to terminals S33 and S34 of the safety relay J1. It should be understood that the configuration of the safety relay J1 and its respective terminals shown in fig. 1 is only an example, and the present disclosure is not limited thereto.

As an example, two contactors KM1 and KM2 may be provided, and two sets of auxiliary contacts of the safety relay are used to control the power supply of the coils of the two contactors KM1 and KM2, respectively.

Referring to fig. 1, the coil anodes of the contactors KM1 and KM2 are connected to the 24V terminal block through the output terminals 13/14 and 23/24 of the safety relay, respectively, and the coil cathodes of the contactors KM1 and KM2 are connected to the 0V terminal block. In addition, the normally open main contacts of the contactors KM1 and KM2 are connected in series between the solenoid valve coil of the solenoid valve group of the hydraulic pitch actuator and the power supply. When the safety chain is disconnected to enable the safety relay to act, auxiliary contacts between two output ends (for example, 13/14 or 23/24) corresponding to any output channel of the safety relay are disconnected, so that coils of the contactors KM1 and KM2 are powered off, and the power supply of electromagnetic valve coils of an electromagnetic valve group of the hydraulic pitch actuator is cut off. The process of controlling the hydraulic pitch actuators using the safety relay will be further described with reference to fig. 3.

In order to improve the reliability of the hydraulic variable pitch safety chain circuit, two groups of emergency stop button auxiliary contacts and a safety relay can be used for forming a double-channel circuit safety chain. That is, the emergency stop button auxiliary contacts K11 may include two emergency stop button auxiliary contacts of the emergency stop button EB mounted on the pitch control cabinet, and the two emergency stop button auxiliary contacts are connected in parallel. When maintenance personnel perform maintenance, overhaul, test and other operations on the hydraulic pitch system and need to cut off a pitch safety chain loop or an uncontrollable condition occurs, an emergency stop button EB can be pressed, so that any loop from S10 to S11 and any loop from S12 to S11 are cut off, and a safety relay acts.

The safety chain of a wind turbine is generally divided into two parts: a main control safety chain and a variable pitch safety chain. The master control safety chain is a safety protection device of the master control system. The master safety chain may provide a master safety chain OK signal node K12 for the hydraulic pitch safety chain. In the normal operation process of the wind generating set, the master control safety chain OK signal node K12 is in a closed state. If overspeed, vibration and the like occur to disconnect the safety chain controlled by the main control safety chain, the OK signal node K12 of the main control safety chain is disconnected, so that the hydraulic pitch safety chain is also disconnected, and the safety relay acts. In addition, as shown in fig. 1, the safety relay may also provide a "pitch safety chain feedback" signal to the master safety chain.

As a "backup energy source" for hydraulic pitch, the accumulator needs to ensure that the internal pressure remains within the normal operating pressure range (e.g., 200bar-250 bar) at any time. Once the accumulator internal pressure is below a predetermined threshold (e.g., 120 bar), there is no guarantee that the unit completes an emergency feathering action. Therefore, a pressure switch needs to be configured on each blade accumulator for monitoring. Accumulator pressure switch K13 (e.g., PS1, PS2, and PS 3) may be connected in series into a plurality of fault nodes of the hydraulic pitch safety chain circuit. When the pressure of the energy accumulator is normal, the energy storage pressure switch K13 is closed; when the accumulator pressure is below the actuation threshold due to an occurrence of an accumulator pressure leak, the accumulator pressure switch K13 is opened.

The number of accumulators per blade may vary from one wind park to another, as may the number of pressure switches. The lowest accumulator pressure value may be considered to select the appropriate pressure switch actuation threshold. It will be appreciated that the number of accumulator pressure switches and accumulator pressure values described above are merely examples, and the present disclosure is not limited thereto. Because the accumulator pressure switch reacts faster than the accumulator pressure sensor, the hydraulic pitch safety chain can respond more timely.

The pitch system OK signal node K15, the switching power supply OK signal node K16 and the lightning protection signal node K17 can be used as protection nodes provided by hardware modules to be connected into a hydraulic pitch safety chain loop.

The pitch controller of the wind generating set can provide a pitch system OK signal node K15 for a hydraulic pitch safety chain loop. As an example, the output state of the pitch system OK signal node K15 may be controlled according to whether various sensor data (e.g., analog signal values such as displacement, pressure, etc.) in the hydraulic pitch system collected by the pitch controller exceeds the limit.

When the pitch system is operating normally, the pitch system OK signal node K15 is closed. When the pitch controller monitors that the pitch system has faults which endanger the safety of the unit, the OK signal node K15 of the pitch system is disconnected.

The switching power supply may provide power for safety relays and other DC powered devices. Referring to fig. 1, a switching power supply is connected to power input terminals A1 and A2 of a safety relay. Although the switching power supply is shown in fig. 1 to provide 24V dc power, this is merely an example, and the present invention is not limited thereto.

The switching power supply may also provide a switching power supply OK signal node K16 for the safety chain loop, so that the output voltage of the switching power supply and the DC supply loop can be monitored. Normally, the switching power OK signal node K16 is in a closed state. As an example, in case that a ground lap occurs on a certain line in the hydraulic pitch system, so that the output voltage of the switching power supply (for example, 24V DC switching power supply) is reduced but no short-circuit trip is caused, the switching power supply OK signal node K16 is triggered (i.e., disconnected), so that the hydraulic pitch safety chain is disconnected, so as to ensure the safety and reliability of the hydraulic pitch system.

The lightning protection module of the pitch system can provide a lightning protection signal node K17 for the hydraulic pitch safety chain loop. The lightning protection module is connected in parallel to a loop of an alternating current main power supply (for example, 230V AC power supply) of the pitch system. Under normal conditions, the lightning protection signal node K17 is closed. When the lightning protection module acts due to overvoltage on an alternating current main power supply (for example, 230V AC power supply) loop of the pitch system, the lightning protection signal node K17 is changed from closed to open so as to ensure the electricity utilization safety and the unit safety of the hydraulic pitch system.

In addition, a delay relay may be provided to monitor the pulse signal output by the pitch controller. The delay relay contact K14 may be connected in series to a plurality of fault nodes of the hydraulic pitch safety chain circuit.

Fig. 2 is a diagram illustrating an example of a delay relay according to some example embodiments.

Referring to fig. 2, the delay relays may include an energizing delay relay (or delay-engaging relay) KT1 and a de-energizing delay relay (or delay-disengaging relay) KT2. The coils of KT1 and KT2 can be connected in parallel, the anodes of the coils of KT1 and KT2 are commonly connected to the output DO of the pitch controller, and the cathodes of the coils of KT1 and KT2 are commonly connected to the 0V terminal block of the switching power supply. KT1 and KT2 can receive pulse signals output by the pitch controller as power signals of the coils.

The pitch controller may output a high-low level switched pulse signal according to the implemented function (e.g., communication heartbeat, controller module health signal, program watchdog, etc.). The delays of the delay relays KT1 and KT2 may be set in association with the high-level duration and the low-level duration of the pulse signal to monitor the pulse signal output by the pitch controller. When the time of the pulse signal output by the pitch controller is maintained at the high level or the low level exceeds the setting time of the delay relay, the pitch controller can be determined to have serious faults.

As an example, the pitch system may cause the pitch controller to output high and low levels for a duration of T according to pitch control logic, communication heartbeat, or other functions _d (e.g., 500 ms). The delay setting values of the delay relays KT1, KT2 can be set to be a preset threshold T _th (e.g., 1000 ms). When unforeseen reasons are met, the pulse signal output by the pitch controller is maintained at a high level or a low level for more than a preset threshold T _th When the relay KT1 or KT2 is operated, the relay contact K14 is triggered, and the safety relay is operated. It will be appreciated that the above-described delay relay setting value T _d And T _th By way of example only, the present disclosure is not limited thereto.

Referring back to fig. 1, the time delay relay contact K14 includes a normally open contact KT2.1 and a normally closed contact KT1.1 connected in series. The energization delay relay KT1 is used for monitoring the high level of the pulse signal. When the high level duration is lower than the predetermined threshold T _th When KT1 does not act, normally closed contact KT1.1 is closed; when the high level duration exceeds the predetermined threshold T _th When KT1 is operated, normally closed contact KT1.1 is opened. The power-off delay relay KT2 is used for monitoring the low level of the pulse signal. When a high level appears, KT2 acts, and normally open contacts KT2.1 are closed; when a low level occurs, the delay starts, when the duration of the low level exceeds a predetermined threshold T _th When the normally open contact KT2.1 of KT2 returns to the pre-operation state (i.e., KT2.1 opens).

As shown in fig. 3, normally open contacts KM1.1 and KM2.1 of the contactors KM1 and KM2 are connected in series, and a 24V terminal strip power supply is connected to anodes of solenoid valve coils in hydraulic pitch solenoid valve groups of three blades of the wind turbine generator set through the contacts KM1.1 and KM2.1, respectively. Although the power supply of the solenoid valve block is shown as 24V DC power in fig. 3, this is merely an example, and the present invention is not limited thereto.

As an example, blade solenoid valve group No. 1 includes emergency feathering solenoid valves (V1.1 and V1.2), pitch enable solenoid valves (V1.3 and V1.4), and pitch bypass solenoid valves (V1.5). The No. 2 blade solenoid valve group comprises an emergency feathering solenoid valve (V2.1 and V2.2), a pitch enabling solenoid valve (V2.3 and V2.4) and a pitch bypass solenoid valve (V2.5). The blade number 3 solenoid valve block includes emergency feathering solenoid valves (V3.1 and V3.2), pitch enable solenoid valves (V3.3 and V3.4), and pitch bypass solenoid valves (V3.5). The cathodes of all solenoid coils are connected to a 0V terminal block.

When any fault node is triggered, the safety chain is disconnected, and the safety relay acts, so that the contacts KM1.1 and KM2.1 are disconnected due to the fact that the coil is in power failure. When the contact (KM 1.1 or KM 2.1) of any one of the contactors KM1 and KM2 is disconnected, the power supply loop of the solenoid valve coil of the hydraulic variable-pitch solenoid valve bank is disconnected, and the solenoid valve is powered off. When the emergency feathering solenoid valves (e.g., V1.1, V1.2, V2.1, V2.2, V3.1, and V3.2) are de-energized, the pressure inside the accumulator causes the hydraulic rod to extend to push the blades to complete the emergency feathering. When the pitch enabling solenoid valves (e.g., V1.3, V1.4, V2.3, V2.4, V3.3, and V3.4) are de-energized, the hydraulic oil passage through the pitch proportional valve control is blocked. Under the condition of power failure, the pitch bypass solenoid valve (for example, V1.5, V2.5 and V3.5) provides a smooth release loop for hydraulic oil of the hydraulic pitch pipeline, and the hydraulic rod can only move in the extending direction, so that the purpose of emergency feathering is achieved.

Through the redundant design of the two groups of auxiliary contacts and the two contactors KM1/KM2 of the safety relay, the safe and reliable cutting off of the power supply of all solenoid valve coils can be ensured when the safety relay acts, and therefore emergency feathering of the wind generating set is realized.

As an example, the normally open contacts KM1.1 and KM2.1 of the contactors may also be used to control the relays PK1, PK2, PK3 in the pitch control cabinet to further improve the reliability of the hydraulic pitch safety chain.

Referring to fig. 3, normally open contacts KM1.1 and KM2.1 of contactors KM1 and KM2 may be connected in series between the coils of control relays PK1, PK2 and PK3 and the power source, and normally open contacts PK1, PK2 and PK3 may be connected in series to the input signal circuit of the pitch proportioning valve. When the safety relay acts, the contactor contacts KM1.1 and KM2.1 are disconnected, the relays PK1, PK2 and PK3 are powered off, and the normally open contacts PK1, PK2 and PK3 enable the input signal loop of the variable pitch proportional valve to be disconnected, so that the input signal of the variable pitch proportional valve sent by the variable pitch controller is kept at 0V, the aim of incapability of opening the pitch is achieved, and meanwhile, the micro-opening action of the proportional valve caused by weak voltage signals at the signal input end of the variable pitch proportional valve can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. The utility model provides a wind generating set's hydraulic pressure becomes oar safety chain, its characterized in that, hydraulic pressure becomes oar safety chain includes: the emergency stop button, the safety relay, the variable pitch controller, the contactor, the switching power supply, the lightning protection module of the variable pitch system power supply and the plurality of fault nodes;

the fault nodes comprise emergency stop button auxiliary contacts, a main control safety chain OK signal node, an energy storage pressure switch, a pitch control system OK signal node, a switching power supply OK signal node and a lightning protection signal node, and are connected to the input end of the safety relay in series;

the coil of the contactor is connected with the auxiliary contact of the safety relay, and the main contact of the contactor is connected in series between the solenoid valve coil of the solenoid valve group for controlling the hydraulic pitch actuator and a power supply;

when any fault node is triggered, the safety relay acts to cut off the power supply of the coil of the contactor, so that the power supply of the electromagnetic valve coil of the electromagnetic valve group of the pitch actuator is cut off, and the wind generating set executes feathering.

2. The hydraulic pitch safety chain of claim 1, wherein the contactor comprises a first contactor and a second contactor;

the coil anode of the first contactor is connected to the anode of the switching power supply through the auxiliary contact of the first output channel of the safety relay, and the coil cathode of the first contactor is connected to the cathode of the switching power supply;

the coil positive pole of the second contactor is connected to the positive pole of the switching power supply via the auxiliary contact of the second output channel of the safety relay, and the coil negative pole of the second contactor is connected to the negative pole of the switching power supply.

3. The hydraulic pitch safety chain according to claim 2, wherein a first normally open main contact of a first contactor and a second normally open main contact of a second contactor are connected in series between a solenoid valve coil of a solenoid valve group of the pitch actuator and a power supply,

when the safety relay acts, the auxiliary contact of each output channel of the safety relay is disconnected to cut off the power supply of the coil of the contactor.

4. The hydraulic pitch safety chain according to claim 2, wherein a first normally open main contact of the first contactor and a second normally open main contact of the second contactor are connected in series between a coil of the control relay and a power supply, and the normally open contacts of the control relay are connected in series to a pitch proportional valve input voltage signal loop,

when the safety relay acts, the input voltage signal of the variable pitch proportional valve is 0V.

5. The hydraulic pitch safety chain of claim 1, further comprising a delay relay for monitoring a pulse signal output by the pitch controller, a contact of the delay relay being connected in series in the plurality of fault nodes.

6. The hydraulic pitch safety chain according to claim 5, wherein the delay relay comprises an energized delay relay and a de-energized delay relay,

the coil of the power-on delay relay and the coil of the power-off delay relay are connected in parallel, and the coil of the power-on delay relay and the coil of the power-off delay relay receive pulse signals output by the pitch controller as power signals;

wherein a delay setting value of the delay relay is associated with a high level duration and a low level duration of the pulse signal.

7. The hydraulic pitch safety chain according to claim 6, wherein,

the delay relay contact comprises a normally closed contact of an energizing delay relay and a normally open contact of a deenergizing delay relay, and the normally closed contact and the normally open contact are connected in series in the plurality of fault nodes.

8. The hydraulic pitch safety chain of claim 1, wherein the scram button auxiliary contacts comprise two scram button auxiliary contacts of a scram button of a pitch control cabinet, and the two scram button auxiliary contacts are connected in parallel.

9. The hydraulic pitch safety chain of claim 1, wherein the stored pressure switch is closed when the accumulator pressure is above a threshold value and is open when the accumulator pressure is below the threshold value.

10. A wind power plant, characterized in that it comprises a hydraulic pitch safety chain according to any one of claims 1 to 9.