7EX470.50-1
Siemens 7EX470.50-1 Digital Protection Relay (Medium-Voltage Network Overcurrent & Earth Fault Protector)
Product Description
The 7EX470.50-1 is a compact digital protection relay designed by Siemens for medium-voltage (MV) electrical networks (up to 36kV), specializing in overcurrent and earth fault protection for distribution lines, transformers, and switchgear. Its core function is to monitor electrical parameters (current, voltage, frequency) in real time, detect abnormal conditions (e.g., short circuits, ground faults), and trigger tripping mechanisms (e.g., circuit breakers) to isolate faulty sections—critical for preventing equipment damage and ensuring network stability in utilities, industrial plants, and renewable energy grids. For example, in a 10kV distribution feeder supplying a manufacturing facility, it can detect a phase-to-phase short circuit (current spiking from 200A to 2000A) and trip the breaker within 50ms, limiting fault duration and avoiding transformer overheating.
Equipped with flexible protection algorithms, the relay supports multiple overcurrent functions (inverse time, definite time, high-set) and earth fault protection (residual current-based), compliant with IEC 60255 standards. These functions are configurable via Siemens’ DIGSI 5 software, allowing customization to network requirements—for instance, setting an inverse time overcurrent curve (IDMTL) to coordinate with downstream protection devices, ensuring selective tripping (only the relay closest to the fault operates, minimizing service disruption). In a solar farm’s MV collection network, this coordination prevents a single inverter fault from shutting down the entire plant.