Sampling time

s

Simulation time-step

Number of generators

-

Number of generator units in the wind park.

Nominal frequency

Hz

Fundamental network frequency

Nominal power

VA

Apparent power rating of one asynchronous machine

Nominal voltage

V

Stator line-line RMS voltage

Stator | Resistance

pu

Resistance of the stator winding of the asynchronous machine

Stator | Reactance

pu

Leakage reactance of the stator winding of the asynchronous machine

Rotor | Resistance

pu

Resistance of the rotor winding of the asynchronous machine

Rotor | Reactance

pu

Leakage reactance of the rotor winding of the asynchronous machine

Mutual reactance

pu

Magnetizing reactance of the asynchronous machine

Inertia constant

s

Combined rotor and load inertia constant

Friction factor

pu

Combined rotor and load viscous friction coefficient

Number of pole-pairs

-

Number of pole pairs

Initial Conditions | Slip

-

Initial slip of the asynchronous machine

Initial Conditions | Electrical angle

deg

Initial electrical angle at t = 0

Initial Conditions | Magnitude

pu

Initial magnitude of the stator current

Initial Conditions | Angle

deg

Initial angle of the stator current

Rotor side converter nominal line-line voltage

V

RMS line-line voltage of the rotor side of the asynchronous machine

Capacitive reactive power

VAR

Reactive power generated by the line filter at the nominal voltage

Quality factor

-

Ratio of the active power consumption to the reactive power generation

Choke | Inductor

pu

Reactance of the choke

Choke | Resistor

pu

Resistance of the choke

DC Link | Capacitance per generator

F

Capacitance of the DC link per generator

DC Link | Nominal DC bus voltage

V

DC link nominal voltage

Winding configuration

-

Winding vector type of the respective side

Nominal voltage

V

Nominal line-line voltage at the respective side

Winding resistance

pu

Winding resistance (copper losses)

Winding reactance

pu

Winding leakage reactance

Magnetization resistance

pu

Core resistance (iron and hysteresis losses)

Magnetization reactance

pu

Core reactance

Cut-off frequency

Hz

Cut-off frequency of the low pass filter

Damping factor

-

Damping factor of the low pass filter

Minimum speed

pu

Minimum angular shaft speed

Maximum speed

pu

Maximum angular shaft speed

Proportional gain (Kp)

-

PI proportional gain for the torque controller

Integral gain (Ki)

-

PI integral gain for the torque controller

Maximum speed output

pu

Maximum speed regulator output

Turbine inertia

s

Inertia of the turbine

Proportional gain (Kp)

-

PI proportional gain for the pitch controller

Maximum pitch angle

deg

Maximum pitch angle of the turbine

Maximum rate of change of pitch angle

deg/s

Slew rate of the change of pitch angle

Pitch time constant

s

Time constant of the pitch control

Proportional gain (Kp)

-

PI proportional gain for the pitch compensation

Integral gain (Ki)

-

PI integral gain for the pitch compensation

Grid-side converter maximum current

pu

Maximum allowed DC current

DC Bus Voltage Regulator | Proportional gain (Kp)

-

PI proportional gain for the DC voltage regulation controller

DC Bus Voltage Regulator | Integral gain (Ki)

-

PI integral gain for the DC voltage regulation controller

Current Regulator | Proportional gain (Kp)

-

PI proportional gain for the current regulator

Current Regulator | Integral gain (Ki)

-

PI integral gain for the current regulator

Current Regulator | Current limit

pu

Maximum regulator current

Maximum modulation index

-

Grid side maximum modulation index

Frequency of the grid-side PWM carrier

Hz

Pulse Width Modulation carrier signal frequency

Minimum flux magnitude

pu

Minimum flux magnitude of the DFIG

Maximum d-axis rotor current

pu

Maximum magnitude of the d-axis component of the rotor current

Reactive Power Regulator | Integral gain (Ki)

-

Integral gain for the reactive power controller

Reactive Power Regulator | Minimum output value

pu

Minimum reactive power output

Reactive Power Regulator | Maximum output value

pu

Maximum reactive power output

Voltage Regulator | Integral gain (Ki)

-

Integral gain for the voltage regulator controller

Current Regulator | Proportional gain (Kp)

-

PI proportional gain for the current regulator

Current Regulator | Integral gain (Ki)

-

PI integral gain for the current regulator

Current Regulator | Current limit

pu

Maximum regulator current

Maximum modulation index

-

Rotorside maximum modulation index

Frequency of the rotor-side PWM carrier

Hz

Pulse Width Modulation carrier signal frequency

Nominal mechanical power output

W

Net mechanical power transferred to the rotor

Coefficients [c1 … c8]

-

Wind model equation coefficients

Rated omega r

pu

Rated rotor (electrical) speed

Cp max

pu

Cp at maximum power

Lambda at Cp max

-

Lambda when Cp is at maximum

Wind speed at nominal speed and at Cp max (must be between 6 m/s and 30 m/s) (m/s):

m/s

Wind speed when Cp is at maximum

Initial wind speed

m/s

Wind speed at the start of the simulation

Rated power at omega “r” and theta zero

W

Nominal power at rated omega “r”

Wind turbine inertia constant H

s

Turbine inertia

Shaft spring constant refer to high-speed shaft:

pu/rad

Shaft spring constant as per-unit of the nominal mechanical torque

Shaft mutual damping

1/pu

Shaft mutual damping as per-unit of the nominal mechanical torque

Turbine initial speed

pu

Turbine speed as per-unit of the nominal speed at the start of the simulation

Initial output torque

pu

Torque output as per-unit of the nominal torque at the start of the simulation