This guide ranks manufacturers by what matters in real projects: standards conformance, installed base, commissioning experience, serviceability, delivery reliability, and lifecycle support across MV/HV protection, control, automation, and auxiliary relays used in. This guide ranks manufacturers by what matters in real projects: standards conformance, installed base, commissioning experience, serviceability, delivery reliability, and lifecycle support across MV/HV protection, control, automation, and auxiliary relays used in. Here is our recommended list of the top ten relay manufacturers. Please note, this list is not presented in a specific order of rank. Each company is included for its unique market position, technological strengths, and value to engineers and designers. As an industry titan, TE Connectivity offers. Protective relays are electrical devices that are designed to detect abnormal conditions in power systems and isolate the affected part of the system. In order to identify problems including overloads, short circuits, and ground faults, they keep an eye on several factors, including current. Over Voltage Relay (OVR): Operates when the voltage at the location where the protective relays are installed exceeds the set value. Detects overvoltage on the power system side due to a generator or other failure and protects the system and equipment on the load side. Product Details: Shenler UL-certified power relays provide reliable performance with an ultra-wide 6-380V AC/DC input range, supporting 5-40A/250-500VAC switching capacity and.