Power Quality Monitoring

T he number of renewable energy producers in the energy grid such as wind or pv has increased over the last few years. Most of these producers use frequency converters that make a non-perfect sine wave, or in the worst-case scenario, a trapezoid signal. Additionally, there is an increasing number of non-linear consumers such as LED´s or switching power supplies

These producers/consumers are causing harmonics to occur on top of the basic sine wave. These waves can go up to hundreds of kilohertz and can be summarized by the THD (Total harmonic distortion) factor, which is given in a percentage.

These harmonics have different effects on the grid:

• Exceeding the given limits for THD can damage components of the grid and reduce its life-time
• Malfunction in the tripping of the circuit breaker protection functions
• Overheating of power transformers/distribution transformers
• Overload of neutral conductors
• Noise caused by frequencies between 10 and 20kHz

Utility companies must detect these harmonics early enough to take the proper countermeasures such as using compensation circuits and filters. Acquiring this signal is only possible with sensors that can transmit the harmonics with a certain accuracy. All GWP sensor products (voltage- and current sensors) can transform high voltage harmonics to low voltage signals up to 150kHz using a passive technology that does not require software compensation.