Renewable Energy Testing Solutions

Testing System Overview

Renewable power plants like wind, photovoltaic (PV) and CHP (Combined Heat and Power Plant) are more and more popular and the amount of already installed units is huge. For the operation at the public grid these renewable power generation units have to fulfill a couple of requirements to contribute to a stable operation of the grid.

The standards, which define the conditions for operating the plant at the grid, vary from country to country: e.g. FGW-TR3, VDE-AR4105, BDEW etc. These regulations define the control of the active and reactive power, the limits of Power Quality emissions and the behavior at grid disturbances.

Active & Reactive Power

Active Power calculation

• Max. active power for 0.2s, 60s and 600s

• Input and output power (DC, AC)
   

Operation at different set point settings for active and reactive power

• Calculation of deviation, min, max, averaged values for each setpoint

• Automatic check if within range

• Transient Behaviour

• Different charts (P, Q, S, U, I, f, cos phi)
   

Power reduction at increasing frequency

• Check if power reduction within tolerance

• Calculation of gradients (%/Hz) and power difference (ΔP)

• Different charts (P, U, I, f)
   

Evaluation of reactive power provision

• Q_ind, Q_cap, Power Factor

• The voltage of positive sequence-system

Behavior at Faults

Dis- and Reconnection tests

• Test of protection equipment – Check Settings, and dis- and reconnection time for over- and under-voltage, over- and under-frequency

Behavior at grid disturbances (LVRT - Low Voltage Ride Through)

• Raw data analysis (waveform) at start and end of the fault

• Analysis of fault length and specification of short-circuit current (peak value, 1⁄2 period value) at different times (t=0, t=150ms, etc.)

• Calculation of normalized active- reactive-
  and apparent power

• Half-wave RMS values for voltages & currents

• Positive-, negative and zero-sequence voltages

• Active-, reactive- and apparent power of positive-, negative- and zero-sequence-system