We provide advanced electrical consultancy for renewable energy projects

We carry out simulation studies on different software platforms, such as PowerFactory (DIgSILENT), PSS/E, PSCAD, and MATLAB-Simulink, etc.:

• Power flow study: the aim of this study is to check the bus voltages and loads of the power equipment and transmission lines of the electrical grid for several operation scenarios to determine if the connection of the power plant in the grid is feasible. It is also used to determine the maximum or statistical active power losses in each element of the network, for its optimization.
• Reactive power capability study: The main objective of this study is to analyse the reactive power capability of the PV plant in relation to the requirements defined in the grid code. The aim is to quantify the reactive power capacity that inverters can supply and absorb within their active power generation range.
• Contingency analysis study: the bus voltages and loads of the power equipment and transmission lines are checked for several grid contingencies (N-1, N-1-1, N-2).
• Short-circuit analysis: the aim of this study is to check the maximum short-circuit current that may occur in the electrical grid due to the power plant connection for several operation scenarios.
• Power quality study: this study aims to determine the power quality at the power plant’s point of connection to size harmonic filters if needed.
• Transient stability study: the objective of this study is to assess the transient response of the power plant in case of grid disturbances and define the parameters to comply with grid code requirements.
• Dynamic studies: this study aims to assess the active power-frequency control and the reactive power control modes of the power plant controller, determine if a STATCOMs is required and its characterization, and define the parameters to comply with the grid code requirements.
• Electromagnetic transient (EMT) study: the objective of this study is to determine the inrush current and voltage transients due to the energization of transformers, lines, capacitors, or other elements of the power plant, and propose specific operation protocols or elements to reduce the impact.
• Grid code connection compliance studies: we have a wide experience in assessing grid code connection compliance in different countries, such as Spain, Italy, Portugal, Brazil, Mexico, Costa Rica, Peru, Bolivia Jordan, Morocco, Tunisia, Mauritania, Ethiopia and South Africa, among others.
• Electrical studies for problem solving: Once the power plant is connected to the grid, additional studies could be developed, such as commissioning tests, or specific studies to determine a particular parameter or to solve a problem in a power plant.

We perform voltage dip tests on wind turbines, PV inverters and synchronous generators powered by diesel and gas.

We designed specialised mobile laboratories to perform voltage dips and fault ride-through tests to wind turbines and power plants. The equipment is highly versatile due to its network connection capacity at different voltage rates and its possibility for adjusting the voltage dips’ depths and durations, according to the operating procedures included in the different grid operators.

Our electrical laboratory has accreditations to perform tests in more than 20 countries around the world and, since 2006, we have successfully performed them in wind farms and PV plants according to the main grid codes in Europe (Germany, Spain, France, UK, Romania, Denmark) and America (USA, Canada, Mexico, etc.). Currently, we are carrying out the accreditation process for several other grid codes in a process of continuous growth.

The Voltage Dip Generator (VDG) unit creates isolated faults by reducing voltage in two or three phases, recording electrical variables during the dip to measure power exchange. Field measurements, pre-test studies, and grid code evaluations culminate in a test report detailing compliance with grid code requirements.

We carry out measurements of the quality of energy supply in electrical networks following the IEC 61000-4-30 and EN 50160 standards and we evaluate the main indicators of electrical networks, including:

• Voltage fluctuations, flicker
• Harmonics, interharmonics and high frequency components
• Voltage dips, surges and interruptions
• Voltage imbalances
• Related statistics

Moreover, we also carry out specific quality measurements of the power supply in wind turbines following the IEC 61400-21-1, NTS and FGW TR3 standards, always working with their most recent revision. Also, we evaluate:

• Power quality (harmonics and flicker)
• Steady-state operation:
  • Observation of active power against wind
  • Maximum active power (losses verification)
  • Reactive power capability
  • Voltage dependency of PQ diagram
  • Unbalance factor
• Control performance:
  • Active power control
  • Active power ramp rate limitation
  • Reactive power control (reactive power, voltage, and power factor control modes)
  • Frequency control
  • Synthetic inertia
• Disconnection from grid
  • Grid protection
  • Reconnection test
  • Test of rate of change of frequency (RoCoF)

We carry out advanced electrical studies on different platforms, such as PowerFactory (DIgSILENT), PSS/E, PSCAD, ANATEM, ATP-EMTP etc. The studies we offer include:

• Technical audits of wind farms
• Dynamic simulations of wind farms
• Power plant operating limits (P-Q Curve)
• Studies for the adaptation of old wind farms to the new grid codes
• Dynamic simulations of wind farms
• Behavior of the wind farm

The validation of the simulation model is intended to show that a mathematical model behaves dynamically in the same way as the real element when faced with the same disturbance, reproducing its response.

Currently, most operators worldwide are requesting the provision of plant simulation models that meet or that are validated for the operating conditions at their site. These models include simulation models of PV inverters, storage systems, wind turbines, simple or hybrid plant controllers, STATCOMs, etc.

We carry out tests for the validation of the models and all simulations for design and parameterization to meet the local operator’s requirements. The IEC 61400-27 standard validates wind turbine simulation models for dynamic power system events. We are accredited for IEC 61400-27-1 validations and we have contributed to developing its editions. Since 2007, we have pioneered model validations per Spanish and German standards, specializing in accurate electric simulation model validation for renewable energy systems.