Voltage- and Frequency-Relay with integrated Vector-Shift-Relay Grid- and Plant Protection.
For more information, we refer you to the datasheet and certificates below which are available to download. Or visit www.ziehl.de and look for the SPI1021 under the Mains monitoring group.
Datasheet
Ziehl Voltage and Frequency Relay SPI1021
Documents
Certificate – CEI 0-21 (Certificate)