Wind Power Plant (Generic)

The Wind Power Plant (Generic) component, shown in Table 1, is a Schematic Editor library block from the Distributed Energy Resources section, of the Microgrid library. It is capable of operating in grid following mode, with active power curtailment supported.

Table 1. Wind Power Plant (Generic) component in the Schematic Editor core library

component	component dialog window	component parameters
Wind Power Plant (Generic)		Property tabs: 1 - General 2 - Wind Turbine 3 - Grid codes 3 - Conv. Extras 4 - Grid Extras

Wind Power Plant (Generic) functional block diagram and main control functionality

The component consists of two main parts: a high level control subsystem and a low level control subsystem with a power stage and necessary measurements included.

High level control subsystem main parts are:

• PQ Control block - Contains regulators for active and reactive power control. The PQ Control block receives power references and measured powers after the transformer (grid side) and calculates reference output currents. These current references are fed to the low level control logic. This control block is active in the grid following mode of operation.
• MPPT Control block -
• Ramping elements - Limit the ROC (rate of change) of the active power reference, reactive power reference, voltage reference, and frequency reference. The rate of change for each function is configured through a corresponding input signal.
• Main state machine - Controls and checks overall functionality of the plant. Operational plant states are described in Main state machine states.

Low level control subsystem main parts:

• Currents control block - Contains regulators for inner current control loops. Input signals to the Currents Control block are reference currents and measured currents before the transformer (converter side).
• Fault state machine - Checks all measurements, signals the fault state, and sends an alarm message. It also immediately opens the MCB (main circuit breaker) on any detected fault. A list of implemented faults is shown in Faults/Alarm messages table.

Wind Power Plant (Generic) power stage

The power stage is shown in Figure 2. The main elements include the average model of the inverter, the input L filter, the transformer, and the MCB that connects the plant to the grid. The transformer can be excluded from the power stage if it is not necessary. Power stage elements are parametrized from the component dialog box.

Wind Power Plant (Generic) component inputs and outputs

This component has one user interface input, one user interface output, and one external input. The user interface input and user interface output are each arrays of 50 elements, while the external input is an array of 5 elements.Table 2 describes the input signals and their order, while Table 3 describes the output signals and their order. Lastly, Table 4 describes the external wind power plant input signals and their order.

All these signals are also defined in the corresponding Wind Power Plant (Generic) UI subsystem using Probe components (for output signals) and SCADA Input components (for input signals), as shown in Table 5. These signals were split and joined by properly configured DER (Generic) Output Split and DER (Generic) Control Join components. The Wind Power Plant (Generic) UI subsystem is located in the same place in the Schematic Editor library as the Wind Power Plant (Generic) component, and it can be unlinked from the library and adopted to the specific needs. Unit [pu] is associated to nominal values, which are either inserted as general tab parameters or derived from them.

* If the values for inputs 17 to 22 are all zeroes, default values will be used.

Table 3. Wind Power Plant (Generic) user interface outputs

Number	Output	Description
0	Enable_fb	A digital output describing the plant converter enable/disable state. The plant is enabled if the output is high.
1	Qref_fb_kVAr	An analog output with the instantaneous value of the applied reactive power reference in the converter. [kVAr]
2	Pnom_kW	An analog output with the value of nominal active power of the converter. [kW]
3	Qnom_kVAr	An analog output with the value of nominal reactive power of the converter. [kVAr]
4	Snom_kVA	An analog output with the value of nominal apparent power of the converter. [kVA]
5	Fmeas_Hz	An analog output reporting the value of the grid voltage frequency. [Hz]
6	Vgrid_rms_meas_kV	An analog output reporting the RMS value of the grid voltage, measured at the grid side of the transformer. [kV]
7	Pmeas_kW	An analog output reporting the instantaneous value of the three-phase active power output of the converter. [kW]
8	Pa_meas_kW	An analog output reporting the instantaneous value of the phase A active power output of the converter. [kW]
9	Pb_meas_kW	An analog output reporting the instantaneous value of the phase B active power output of the converter. [kW]
10	Pc_meas_kW	An analog output reporting the instantaneous value of the phase C active power output of the converter. [kW]
11	Qmeas_kVAr	An analog output reporting the instantaneous value of the three-phase reactive power output of the converter. [kVAr]
12	Qa_meas_kVAr	An analog output reporting the instantaneous value of the phase A reactive power output of the converter. [kVAr]
13	Qb_meas_kVAr	An analog output reporting the instantaneous value of the phase B reactive power output of the converter. [kVAr]
14	Qc_meas_kVAr	An analog output reporting the instantaneous value of the phase C reactive power output of the converter. [kVAr]
15	Smeas_kVA	An analog output reporting the instantaneous value of the three-phase apparent power output of the converter. [kVA]
16	PFmeas	An analog output reporting the value of the converter output power factor.
17	Vconv_rms_meas_V	An analog output reporting the RMS value of the converter voltage, measured at the converter side of the transformer. [V]
18	rotational_speed_RPM	An analog output with the rotational speed of the wind turbine. [RPM]
19	wind_speed_m_per_s	An analog output with the instantaneous wind speed value. [m/s]
20	turbine_stalled	A digital output with the information when the turbine is stalled.
21	pitch_ctrl_on	A digital output with the information when the pitch control is active.
22	avg_wind_speed_1	An analog output with the value of average wind speed, calculated over time interval 1. If default wind turbine protection is deactivated, its value will be 0. [m/s]
23	avg_wind_speed_2	An analog output with the value of average wind speed, calculated over time interval 2. If default wind turbine protection is deactivated, its value will be 0. [m/s]
24	avg_wind_speed_sc	An analog output with the value of average wind speed, calculated over time interval (SC). If default wind turbine protection is activated, its value will be 0. [m/s]
25	prot_trip	A digital output with the information of default wind turbine protection status. If the protection has tripped, the value will be 1.
26	P_red_on	A digital output with the information on the status of power reduction for Storm Control protection mode. If the wind speed exceeds the power reduction wind speed for Storm Control (Input 9), the value will be 1.
27	P_cut_out	A digital output with the information on the status of power cut out for Storm Control protection mode. If the wind speed exceeds the power cut out wind speed for Storm Control (Input 11), the value will be 1.
28	state	An analog output reporting the code of the state of the converter.
29	alarm_msg	An analog output reporting the value of the alarm message. In order for the converter to return to normal operation after the alarm has been triggered, all alarms must be reset.
30	nom_wind_speed_m_per_s	Nominal wind speed of the turbine. [m/s]
31	MCB_status	A digital output with the information about the state of the main circuit breaker (contactor). The contactor is closed if the value is high.
32	Lvrt_active_status	A digital output that signals the status of the LVRT unit. If high, the LVRT unit is active and contributing active and reactive power to the grid, otherwise it is not active.
33-49	reserved_outs	Outputs that are not used.

Table 4. Wind Power Plant (Generic) external inputs

Number	Input	Description
0	Wind speed	Wind speed. Affects the available power of the plant. [m/s]
1-4	reserved_exts	Inputs that are not used.

Table 5. Wind Power Plant (Generic) UI subsystem

Wind Power Plant (Generic) UI	Wind Power Plant (Generic) UI internals

Wind Power Plant (Generic) operational states

Component dialogue box and parameters

The Wind Power Plant (Generic) dialogue box consists of four tabs for specifying parameters of the component. Unit [pu] is associated to nominal values, which are inserted as general tab parameters or derived from them.

Tab: "1 - General"

In this component tab, the general parameters of the Wind Power Plant and the grid can be specified.

Tab: "2 - Wind Turbine"

In this component tab, parameters that are related to the Wind Power plant can be specified.

Tab: "3 - Grid codes"

In this component tab, different Grid code parameters can be specified. Currently, LVRT (Low Voltage Ride Through), VoltVAr, HzWatt, and VoltWatt functionalities are supported.

If LVRT and VoltVAr functionalities are both enabled, then the VoltVAr curve has priority over the LVRT reactive power contribution setting (Q_contribution).

The VoltVAr curve is linearly extrapolated for voltage values below and above the minimum and maximum values. Also, the curve is limited by a maximum value of reactive power which can be produced or stored. This limit is calculated as $Q_{max}=\left(1+opc\_pu\right)* Q_{nom}$ , where opc_pu is the overpower capability.

If LVRT and HzWatt functionalities are both enabled, then the HzWatt curve has priority over the LVRT active power contribution setting.

If the frequency value is below the minimum value or above the maximum value, then the Grid frequency out of range error will appear. The HzWatt curve is limited by a maximum value of active power which can be produced. This limit is calculated as $P_{max}=\left(1+opc\_pu\right)* P_{nom}$ , where opc_pu is the overpower capability.

If LVRT and VoltWatt functionalities are both enabled, then the VoltWatt curve has priority over the LVRT active power contribution setting. But, if HzWatt and VoltWatt functionalities are both enabled, then the HzWatt curve has priority over the VoltWatt curve.

The VoltWatt curve is linearly extrapolated for voltage values below and above the minimum and maximum values. Also, the curve is limited by a maximum value of active power which can be produced. This limit is calculated as $P_{max}=\left(1+opc\_pu\right)* P_{nom}$ , where opc_pu is the overpower capability.

Tab: "4 - Conv. Extras"

In this component tab, additional parameters that are related to the converter can be specified.

Tab: "5 - Grid Extras"

In this component tab, additional parameters that are related to the grid can be specified.

Example

Overall behavior and control methodologies can be better understood with the use of the given example:

Model name: wind power plant gen.tse

SCADA interface: wind power plant gen.cus

Path: /examples/models/microgrid/wind turbine//wind power plant (generic)