Finder Introduces the New Type 70.33 SPI

The catalog dedicated to Finder control relays has been expanded to include an Interface Protection System (IPS) designed in strict compliance with the CEI 0-21 standard

The landscape of energy infrastructure is undergoing a profound transformation driven by decentralization and the widespread adoption of micro-grids. In this era of transition, maintaining the stability of interconnections between local generation systems—such as photovoltaic plants—and the public distribution grid has become an absolute priority. To meet these evolving technological and regulatory challenges, Finder’s renowned 70 Series of line monitoring relays expands with the introduction of the Type 0.33.0.230.9011, a cutting-edge Interface Protection System (SPI) designed in strict accordance with the CEI 0-21 standard. The primary objective of the device is clear: ensuring grid safety, operator protection, and maximum overall energy efficiency.

The technological core of the Type 70.33 lies in its ability to constantly and accurately monitor electrical grid parameters. The device is designed to trigger the prompt tripping of the Interface Device (DDI) whenever voltage and frequency values exceed the strict tolerances defined by current regulations.

Specifically, the relay performs continuous measurement and control of:

- Overvoltage and undervoltage, analyzed at both phase-to-neutral and phase-to-phase levels;
- 10-minute average voltage, a crucial parameter to prevent long-term potential rise phenomena;
- Underfrequency and overfrequency, essential for preserving the dynamic balance of the electrical power system.

For modern micro-grids, the Type 70.33 also integrates sophisticated RoCoF (Rate of Change of Frequency) monitoring. This function calculates the time derivative of the frequency, instantly intercepting rapid variations that could otherwise compromise the stability of the energy island.

Developed to satisfy the needs of panel builders and system integrators operating on a global scale, the Type 70.33 makes installation versatility one of its key strengths. It features a wide-range universal supply voltage, capable of operating on both direct and alternating current (24…48 V DC, 110…240 V AC). This flexibility simplifies control panel design and optimizes inventory management by significantly reducing stock codes.

Functional safety is backed by a redundant measuring system and intelligent operations management: the device includes digital inputs for controlling the Interface Device (DDI), external signals, and local commands, alongside the automatic generation of an error log for diagnostic analysis. Finally, to eliminate human error and accelerate on-site commissioning, the relay's internal memory features pre-set Test Box 1 and 2 programs, specifically designed to guide operators through initial setup and periodic regulatory testing. This control relay it's currently available only for the italian market.