Voltage Stabilization in the Supply Grid

Protecting STATCOMs from Short-Circuit Currents

Over the course of the energy transition, conventional large-scale power plants are slowly being shut down. This leaves a gap in the provision of reactive power, an important instrument for stabilizing grid voltage. This task is now increasingly handled, among others, by STATCOM systems capable of rapidly compensating for fluctuations.

However, reliable voltage control can only be achieved if the system is effectively protected against short-circuit currents. It therefore requires signal conditioners that accurately transmit measured values to safety systems within microseconds.

A Key Technology for Modern Supply Grids

STATCOMs (static synchronous compensators) are power-electronic compensation systems used to stabilize the voltage in the supply grid. Voltage fluctuations are compensated as required by absorbing or feeding in reactive power. If the grid voltage drops, the system feeds capacitive reactive power into the grid; if the grid voltage is higher than that of the STATCOM, the device absorbs inductive reactive power.

If a short circuit occurs in the supply grid, the power supply to the STATCOM valves is immediately disconnected. Without this protective mechanism, the system’s power electronics may be damaged, negatively impacting voltage control as a result. Current monitoring with the help of fast-responding signal conditioners installed at each of the three phases of the system ensures high availability of the STATCOM systems.

Why Knick ?
With 480 calibrated, switchable measuring ranges and a broad-range power supply for all common supply voltages, the P27000 is the “multimeter” among signal conditioners. The series guarantees a nearly perfect, distortionfree signal transmission thanks to a gain error of < 0.08 % and a high cutoff frequency of 10 kHz or, as in the application, 20 kHz. Moreover, the signal conditioners feature plug-in screw terminals for quick and easy assembly and a compact design.

Optimum Protection Against Short-Circuit Currents with Knick’s P27000 Signal Conditioner

The P27000 series signal conditioners have proven to be an excellent solution for STATCOM manufacturers. Thanks to a high cutoff frequency of 20 kHz, these devices can process even rapidly changing input signals. With a gain error of < 0.08 % and a T₉₀ response time of < 70 μs, the measured values are transmitted to the circuit breaker almost instantaneously.

The rapid signal processing protects not only the STATCOM components but also enables manufacturers to define higher overcurrent limits, thus optimizing their product's dimensioning.