GE Multilin UR-8AH / UR8AH UR Series CT/VT Module

Description

The GE Multilin UR-8AH is an analog AC measurement interface module developed for the Universal Relays platform that provides three 1A/5A Phase CTs, one 1A/5A Ground CT, and 4 VTs to step down primary electrical grid signals into precise secondary values. This configuration allows the hosting relay chassis to sample, meter, and monitor crucial utility parameters including current, voltage, active power, energy, frequency, and circuit demand factors.

The primary function of the UR-8AH is to act as an isolated instrument transformer interface, converting high-magnitude high-voltage system lines into lower operational signals that can be recognized and modulated by the internal processing logic. As a legacy hardware option, it is engineered to operate on legacy equipment tiers carrying firmware version 3.5x or earlier, establishing standard 4CT/4VT matching layouts. This module provides critical safety isolation between secondary instrument circuits and ground, delivering accurate data streams used by protection loops to isolate faulted primary components. All parameter adjustments, calibration thresholds, and trend logs are interfaced using General Electric Multilin's EnerVista UR workstation software.

Features

• Standard 4CT/4VT Interface Layout: Features three 1A/5A phase current inputs, one 1A/5A ground current input, and 4 voltage transformer paths.
• Legacy Firmware Support: Optimized for legacy UR installations running firmware version 3.5x or lower.
• High-Accuracy Parameter Metering: Delivers secondary sensing resolution for voltage, current, power, energy, and grid frequency metrics.
• EnerVista Software Configuration: Combines with EnerVista UR interfaces for streamlined data export, trending, and graphical parameter review.

Applications

• Substation Feeder Monitoring: Deployed inside traditional utility panels to capture current and voltage waveforms across key distribution circuits.
• Legacy Protective Relay Upgrades: Installed within retrofitted configurations to replace faulty analog acquisition cards in legacy UR relay groups.
• Industrial Electrical Plant Safeguards: Measures transformer and large electrical distribution loops to supply continuous utility data to central automation networks.

Technical Specifications

Installation Guidelines

• Primary Circuit Isolation: Prior to removing or installing the module, disconnect and isolate all primary and secondary power lines from the relay case. Short-circuit all external CT secondary lines to avoid high-voltage transients.
• Electrostatic Grounding Procedures: Technicians must utilize a grounded ESD wrist strap when inserting or removing this analog instrumentation card to safeguard embedded analog-to-digital processing components.
• CPU Hardware Co-linking: Ensure this legacy card is paired with compatible legacy processing components such as the UR-9A, UR-9C, or UR-9D CPU cards.
• Chassis Attachment: Slide the assembly straight along the dedicated enclosure chassis guide slots until the analog terminal headers align properly with the rear backplane assembly. Fasten faceplate locking screws tightly.