UR8LH GE Multilin UR-8LH Universal Relay CT/VT Module

Description

The UR-8LH (UR8LH) is a high-performance current transformer and voltage transformer (CT/VT) interface module developed for the General Electric Universal Relay (UR) series. This module functions as the primary analog input interface, scaling down high-voltage and high-current grid values into precise, low-level signals that the internal relay processing unit can safely analyze. It features an integrated architecture providing 4CT and 4VT channels along with enhanced diagnostic capabilities. The UR-8LH continuously verifies analog signal integrity through an embedded hardware algorithm, enabling immediate detection of signal anomalies to ensure substation protection system reliability. System operators can monitor live metering values, ratios, and diagnostic data locally via the relay front faceplate liquid-crystal display or remotely through the EnerVista UR software suite.

Features

• Provides a combined 4CT and 4VT channel configuration within a single slot module.
• Features enhanced diagnostic algorithms for real-time validation of analog signal integrity.
• Supports standard 3-phase current monitoring plus dedicated ground current detection.
• Delivers seamless integration with the GE Multilin Universal Relay architecture.
• Enables high-precision scaling of hazardous system current and voltage levels for safe relay calculation.

Applications

• Utility and industrial substation protection and control systems.
• Three-phase feeder, transmission line, and transformer monitoring.
• High-reliability power system automated diagnostic architectures.
• Retrofitting and upgrading existing GE Universal Relay hardware configurations.

Technical Specifications

Installation Guidelines

• Module Insertion: Ensure the Universal Relay chassis is completely powered down before inserting or replacing the module to prevent damage to internal backplane connectors.
• CT Secondary Circuiting: Never open-circuit a current transformer secondary circuit while the primary side is energized. Ensure all CT blocks are shorted securely prior to removing wiring or the module.
• Wiring Integrity: Route analog input signals through shielded twisted-pair cables to mitigate the effects of electromagnetic interference (EMI) and radio frequency interference (RFI) common in high-voltage substations.
• Software Configuration: Following physical installation, connect via EnerVista UR software to map the new hardware matrix and verify that the ratio settings match the primary instrument transformers.