The protection system interface (SPI) PMVF50 has been designed according to the CEI 0-21, June 2012 edition, and is used in the case of connection of a system of local generation in parallel with the low voltage network of the distributor. Controls concerning limits on the voltage and frequency. In the case at least one of voltage and frequency appears outside of the allowable limits, the SPI must intervene de-energizing a relay output to the release of the device interface (DDI). PMVF50 is equipped with 4 inputs with the following functions:
feedback status of DDI
external signal to frequency selection (network failure of communication)
local control for frequency selection
remote trip (forced opening of the DDI regardless of the values of voltage and frequency).
In addition, there are 2 relay outputs for:
opening and closing DDI
opening of reinforcement device (programmable retentive normally energized or normally de-energized retentive impulsive adjustable).
The command for the device of reinforcement is required for installations above 20kW and is constituted by a delayed signal of 0.5s compared to the opening command of the DDI, sent only if the DDI fails sectioning.
The PMVF50 has available two relay outputs for additional:
independent signal in the case of imbalance of power (LSP)