*1.8.2. Operational monitoring & communication*

Wind plants are required to send a wide range of real-time data points to the control and dispatch centers of the grid operator. These include status indications and measurements collected through the supervisory control and data acquisition (SCADA) system. The data points include:


Increasingly, the real-time (electrical and meteorological) data is being used by grid opera‐ tors/planners for wind power forecasting. In one example, the New York Independent Sys‐ tem Operator (NYISO) has developed a program that integrates wind forecast into the realtime dispatch [32]. NYISO uses its wind forecast to predict the output level over the next hour, broken up into 5-minute time steps. At each time step, NYISO determines the output level at which the wind plant is economic to operate by using an economic offer curve sup‐ plied by the wind plant. If the wind plant is economic at an output level lower than the fore‐ cast level, NYISO will send a curtailment signal to commanding the wind plant to reduce its output. In China, the National Electric Power Dispatching and Communication Center (NEPDCC) uses the real-time wind power operation information from the different regional and provincial grids in China to perform its online transmission reliability and generation adequacy studies [10].

#### **1.9. Grid compliance validation**

Studies are performed to investigate the impact of any the new generation added to the grid. The connection of a new wind power plant will be authorized only if the performed connec‐ tion impact assessments and associated tests show that the integration of new generation does not lead to a deterioration of the reliability and operational security of the system.

#### *1.9.1. System impact studies*

tions is limited by the rating of the rotor side converter, however, in the case of full convert‐ ers, the control range can be significantly wider and the control can be made more effective.

There are options for implementing and triggering PSS functions in wind plants. One of them is based on the frequency deviation. Studies were carried out to demonstrate that both active and reactive power control could be used effectively to damp inter-machine oscilla‐ tions and to investigate the impact of the wind plant location on the damping effectiveness [33], [48]. It was found that, in general, active power control is less dependent on location, but still more effective when the point of POI of the wind plant was located close to a syn‐

Wind plants are required to send a wide range of real-time data points to the control and dispatch centers of the grid operator. These include status indications and measurements collected through the supervisory control and data acquisition (SCADA) system. The data

**•** electrical measurements the at POI and/or collector system feeders, including: phase and line voltages and currents, actual and available MW and Mvar outputs, and average

**•** operating status signals, including: transformer tap positions, status of dynamic compen‐

**•** meteorological data at the wind farm, including: wind speed and direction at individual

Increasingly, the real-time (electrical and meteorological) data is being used by grid opera‐ tors/planners for wind power forecasting. In one example, the New York Independent Sys‐ tem Operator (NYISO) has developed a program that integrates wind forecast into the realtime dispatch [32]. NYISO uses its wind forecast to predict the output level over the next hour, broken up into 5-minute time steps. At each time step, NYISO determines the output level at which the wind plant is economic to operate by using an economic offer curve sup‐ plied by the wind plant. If the wind plant is economic at an output level lower than the fore‐ cast level, NYISO will send a curtailment signal to commanding the wind plant to reduce its output. In China, the National Electric Power Dispatching and Communication Center (NEPDCC) uses the real-time wind power operation information from the different regional and provincial grids in China to perform its online transmission reliability and generation

Studies are performed to investigate the impact of any the new generation added to the grid. The connection of a new wind power plant will be authorized only if the performed connec‐ tion impact assessments and associated tests show that the integration of new generation does not lead to a deterioration of the reliability and operational security of the system.

sation systems, and the action of main switchgear and protection systems

turbines, ambient temperature, atmospheric pressure, and precipitation.

chronous generator plant.

points include:

358 Advances in Wind Power

MW.hr yields

adequacy studies [10].

**1.9. Grid compliance validation**

*1.8.2. Operational monitoring & communication*

In general, the studies performed for the connection of wind plants are similar to those for a conventional thermal or hydroelectric plant. The purpose of these studies is to veri‐ fy that the coordinated operation of all the units within the plant complies with the gen‐ eral and project-specific requirements stipulated by the grid operator. Those studies typically include [8]:


#### *1.9.2. Wind generator models*

System planners and operators use simulations to assess the potential impact of contin‐ gency scenarios on system performance and to assess the ability of the power system to withstand such events while remaining stable and intact. As discussed in Sections 1.3–1.8, the wind plant control is composed of several levels with different response characteris‐ tics, including the WTGs, wind plant controller, reactive power compensation equipment, and on-load tap changers. Thus, it can be quite challenging to design a collective control scheme for the wind plant to meet the required dynamic response at the POI under all operating conditions. This is typically examined in transient stability studies, where all relevant components and their control loops are modeled. For this type of study, generic simulation models often do not exhibit the necessary level of precision. Thus user-writ‐ ten, validated models are generally needed.

#### *1.9.3. Grid connection testing*

Passing the field validation tests is a prerequisite for the permission of interconnection of some grid operators. These tests are performed in order to:


Figure 19 shows the main areas of wind power plant and wind turbine testing. Type tests are tests of representative equipment performed by the manufacturer in the presence of third party certifiers. The intent is to demonstrate that a particular equipment design exhib‐ its specific performance that can be generalized to all other equipment of that same design [33]. These include validations of the power performance, load calculations, noise levels, and voltage/frequency operation ranges. Long-term harmonic measurements are also per‐ formed to establish the harmonic emission spectrum. These measurements are generally re‐ peated for each wind plant at the POI to account for the emissions of auxiliary equipment and the amplifications caused by the collector system and the grid itself.

**Figure 19.** Grid connection tests of wind plants and wind turbine generators.

Other wind plant field tests include active power and ramp rate control. Depending on the approach of the grid operator, frequency control capabilities (including inertia control and over-frequency response) are either tested at the WTG level (e.g. HQTE) or wind plant level (e.g. UK). The reactive power range and voltage control are also tested to verify the capabili‐ ty of the central wind plant controller and any compensation equipment to respond to volt‐ age deviations as quickly and sufficiently as required.

The data gathered through the online monitoring systems during the life-time of wind plants is also used for performance evaluation. This data, including snapshots of the wind plant behavior taken during external and unscheduled events (such as disturbances or large wind changes) is particularly useful in fine-tuning the wind plant parameters for optimal grid compatibility. The large-scale deployment of phasor measurement units (PMU) by sys‐ tem operators would also open the door for a variety of advanced monitoring and control applications.
