NB/T 31018-2018Technical specification of electric pitch control system for wind turbine generator system (English PDF)

3.1 supply disconnection

influential long-term interruption of power supply due to the disconnection of the switch

3.2 failure

termination of the implementation of certain specified function

Notes:

1 This concept of “failure” as definition does not apply to function items consisting of software only.

2 After failure the function item has a fault.

3 "Failure" is an event, as distinguished from "fault", which is a state.

3.3 safe-chain

hardware protection circuit constituted by several key protection nodes in series of a wind turbine generator, which is independent of control system

3.4 fault

state characterized by inability to perform a specified function, which does not include the states where the specified function cannot be implemented during preventative maintenance and other planned action, or for lack of external resources and which is often the result of a failure of a function item itself, but may exist prior to failure

3.5 normal shutdown

shutdown with the whole process under the control of the control system

3.6 emergency shutdown

wind turbine generator system being made shutdown quickly due to triggering of the safe-chain

3.7 electric pitch control system

device for adjusting the blade angle which mainly comprises a pitch controller, a pitch motor, a pitch driver, a backup power supply and other components

3.8 pitch driver

device for adjusting the blade angle of wind turbine generator system by driving the pitch motor

3.9 backup power supply

power supply that provides energy support for the electric pitch control system when the power grid is powered down

3.10 feathering

geometric angle of attack of the wind turbine blades changing to a state where the sum of the wind turbine blades approaches zero lift, which is usually divided into normal feathering and emergency feathering

3.11 pitch angle

included angle between the blade chord line and the wind turbine blade rotating surface at the specified blade radial position

3.12 operating blade angle range

working range of the blade pitch angle corresponding to the normal operating range of the wind turbine generator system

3.13 the maximum pitch rate

maximum allowable pitch angle change rate

3.14 redundancy

technology of using two sets of devices or systems, with the objective of ensuring that in the event of failure of one set the other set is able to effectively perform the required function

3.15 blade

components that absorb wind energy to drive the wind wheel to rotate

4.1 Service conditions

4.1.1 Normal operating environment conditions

It shall be suitable for the following conditions and can work normally:

a) working environment temperature.

1) normal temperature type: -20°C~+45°C.

2) low temperature type: -30°C~+45°C.

b) relative humidity.

The air shall be clean, the relative humidity shall not exceed 50% at a maximum temperature of +45 °C. At low temperatures, higher relative humidity is allowed. For example, the relative humidity is 95% at +20°C, considering that condensation may occur in case of temperature changes.

c) altitude <= 2,000m.

4.1.2 Normal test environment conditions

Operating climate conditions are mainly included, test shall be carried out under the following atmospheric environment:

a) environmental temperature: below 20°C.

b) relative humidity: <=90%.

c) atmospheric pressure: 86kPa~106kPa.

4.1.3 Power supply conditions

4.1.3.1 AC power supply

a) Power frequency range: 47.5 Hz ~ 51.5 Hz.

b) Allowable fluctuation range of the power supply voltage: -10% to +10% of the voltage rating.

c) The unbalancedness of power supply shall meet the provisions of GB/T 15543-2008, Clause 4, and work normally within the scope.

d) The power supply waveform is sinusoidal wave with a total harmonic content of less than 5%.

4.1.3.2 DC power supply

a) The permissible deviation range of power supply voltage: -15%~+10%.

b) The power supply voltage ripple coefficient shall be less than 5%.

4.1.4 Requirements of the use place

a) In the environment, there shall be no corrosive gas or conductive medium that damages insulation, no medium that causes fire or explosion, and no obvious and serious mold.

b) The use place shall prevent the ingress of rain, snow and sand.

c) The grounding resistance of the use place shall be less than or equal to 4ohm.

d) The requirements for special use places are specified in GB/T 19608.1, GB/T 19608.2 and GB/T 19608.3.

4.1.5 Other service conditions

When the environmental conditions specified in 4.1.1~4.1.4 are exceeded, the manufacturer shall sign a special agreement with the user.

4.2 Structural requirements

4.2.1 Cabinet design requirements

a) The construction of cabinet shall comply with the provisions of GB 20641.

b) The enclosure, appearance and surface shall be free of scratch or deformation, and shall meet the provisions of 6.2.1 in GB/T 3797-2016.

c) Refer to GB 4208 for the description of protection level. The specific requirements are as follows:

1) The cabinet body protection level is IP 54.

2) The protection level of exposed connectors is IP 65.

3) The protection level of all external sensors and switches are IP 65.

If the user has special requirements, it shall be determined by the manufacturer and the user through negotiation.

4.2.2 Electrical connection requirements

They shall meet the requirements specified in GB 5226.1, Clause 13.

4.2.3 Components and parts requirements

Components and parts used in the system shall meet the requirements specified in the corresponding standards. Where, a) The programmable controller shall meet the provisions of GB/T 15969.1 and GB/T 15969.2.

b) The wires and cables of the cabinet body shall meet the requirements of GB 5226.1, Clause 13.

c) The cabinet connector shall meet the requirements of EN 175301-801.

4.3 Functional requirements

4.3.1 Pitch function

4.3.1.1 Manual switch pitch function

The system shall have the function of manually switching on and off the pitch, and be capable of inching control on each blade separately. Only one blade is allowed to be controlled at the same time and the other blade can be driven only after the controlled one returns to a safe position.

4.3.1.2 Automatic pitch function

During normal operation, the pitch system shall be able to receive instructions from the control system of the wind turbine generator system, adjust the pitch angle in real time, reduce the load level borne by the generator system, and achieve the optimal and safe operation of the generator system. The pitch system shall be able to start automatically, change the pitch automatically and achieve feathering automatically according to the requirements of the main control, for example, it can control the pitch by issuing speed and pitch position instructions with the control system of the wind turbine generator system. The pitch system shall be able to work normally in the whole pitch control range, with the blades synchronous. The pitch performance shall meet the following technical requirements:

a) The maximum pitch rate of the three blades shall not be greater than the maximum design speed of the generator system.

b) The control precision of the pitch driver is not more than 0.05°.

c) The recommended value of the asynchrony of the three blades shall not be more than 1°.

d) In case of continuous pitch, the time from the time when the pitch system receives the pitch change instruction issued by the main control system to the time when the pitch bearing starts to act shall not be greater than 200 ms.

e) The pitch controller instruction scanning cycle shall not be more than 20 ms.

4.3.1.3 Man-machine service operation function

Information interaction: inquiry and setting of pitch control system parameters, system status check and fault diagnosis information check.

Speed control: where the pitch control system is in manual mode or maintenance mode, inching control may be carried out on the pitch direction and pitch rate of each blade through the man-machine interface.

Position control: where the pitch control system is in manual mode or maintenance mode, position control may be carried out on each blade through the man-machine interface. The blade pitch speed and given position may be set.

Calibration: the pitch control system has the function of calibrating the 0 position of the encoder or the position of the limit switch.

4.3.2 Safe feathering

4.3.2.1 Power failure of the system

In case of power failure of the system, the backup power supply of the pitch system shall be automatically switched on to complete safe feathering.

4.3.2.2 Communication fault

The pitch system shall be able to automatically complete safe feathering in case of any communication fault between the pitch system and the main control system.

4.3.2.3 Safe-chain disconnection

The safe-chain is divided into two parts: the safe-chain of the pitch system and that from the main control system to the pitch system. If the safe-chain is disconnected, the pitch system shall be able to automatically complete safe feathering.

4.3.3 Fault diagnosis

The pitch system shall have self-diagnosis and protection functions to detect the fault or abnormal conditions of the equipment in real time, and it shall be provided with a good security policy for processing. It shall have complete accident record information to facilitate fault diagnosis, and the information can be timely sent to the control system. The diagnosis and protection may cover the following aspects:

a) lightning protection action.

b) action of fuse or protection switch.

c) abnormal cabinet body temperature.

d) communication timeout or interruption.

e) pitch controller fault (for pitch system with centralized controller).

f) driver fault, which generally includes the following items:

1) low voltage of DC bus;

2) DC bus overvoltage;

3) overcurrent of the driver;

4) overtemperature of the driver;

5) power switch fault;

6) abnormal internal power supply;

7) braking resistor circuit fault;

8) phase loss of the motor:

9) short circuit, open circuit and numerical abnormality of speed and position sensor;

10) fault of internal fan.

g) motor fault, which shall generally include the following items:

1) overtemperature of the motor;

2) overcurrent of the motor;

3) motor stall protection;

4) abnormal braking of the motor.

h) charger fault.

i) open-circuit of charger circuit.

j) abnormal voltage of backup power supply, including overvoltage and undervoltage.