STC "Mechanotronica" presented the BMRZ-50 protection and automation relay for 6–10 kV power grids, designed for substations and distribution points with alternating, rectified or direct operating current.
The device performs relay protection, signaling and automatic control of circuit breakers (ACB). The mechanical shunt release relay and current infeed allow operation without the supply of operating current.
BMRZ-50 supports operation via USB without power, is compatible with the unified software "Configurator-MT", is equipped with a self-diagnosis function, non-volatile indicators and a selector for the direction of single-phase earth faults (SNOZZ), which eliminates additional equipment. Power can be supplied from current circuits or operating current circuits, and the shutdown electromagnet operates through a shunt release relay.
Key characteristics: rated phase current 1 A/5 A (range 0.3–150 A), zero sequence current 0.01–4 A, voltage 2–260 V, frequency 45–55 Hz, thermal resistance up to 15 A continuously and 200 A for a short time, operating temperature −40…+55 °C, protection IP54. Protection functions include instantaneous overcurrent protection, maximum current protection, arc protection, protection against single-phase earth faults, protection against phase loss, circuit breaker backup and automatic reclosing.
BMRZ-50 opens up wide opportunities for import substitution in 6–10 kV networks, replacing foreign protection relays with Russian equipment. It can be used at existing substations and new distribution points with a limited budget, in circuits with an isolated neutral and without the supply of operating current. Compactness, overload resistance and built-in self-diagnosis functions make the device promising for modernizing networks and increasing the reliability of domestic energy.
6–10 kV networks are the basis of the distribution infrastructure in Russia: they are used at urban and industrial substations, in the power systems of large enterprises, mines, factories, transport hubs and housing and communal services facilities. Such networks power most residential areas and production sites, providing communication between high-voltage trunk lines and end consumers.