A design of digital power calibration device in 3/2 connection smart substation

Abstract

In 3/2 connection smart substation, the voltage and current sampling values of electronic transformers in different bays are usually transmitted to a digital power meter through a cascade of merging units or network. The synchronism of voltage and current sampling time influences accuracy of power metering. So it is a key problem to synchronize the sampling values of multi-bays. A new digital power calibration device is designed, which applies to 3/2 connection system. It receives simultaneously the merging units IEC61850-9-2 messages of the PT in the bus and the CT in different bays by multi-fiber ports. Also, it uses the information of the messages and Fourier transform to compensate power angle deviations caused by synchronism. According to test data, the new device can compensate power angle deviations and achieve accurate power metering in 3/2 connection system.

Keywords

• smart substation
• 3/2 connection
• digital power metering
• synchronism
• Fourier transform