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

Product Overview

The GE UR-8AH is a CT/VT Module (Current Transformer / Voltage Transformer) from GE Multilin, designed for the UR Series Universal Relay platform. This module scales down the voltage and current values of the power system to manageable levels for the Universal Relay, ensuring precise measurement and protection. It provides three 1A/5A Phase CTs, 1A/5A Ground CTs, and four Voltage Transformers (VTs) for comprehensive power system monitoring.

The UR-8AH is best used with older UR CPUs such as the UR-9A, UR-9C, or UR-9D, and requires firmware version 3.5x or earlier for compatibility. The module features secondary winding grounding for enhanced operator safety and supports configuration via EnerVista UR software.

Key Features

• 3 × Phase CTs (1A/5A) for current monitoring
• 1 × Ground CT (1A/5A) for ground fault detection
• 4 × Voltage Transformers (VTs) for voltage measurement and scaling
• Secondary winding grounded for enhanced operator safety
• Fault detection capability to identify unsafe system conditions
• Configurable CT and VT settings via EnerVista UR software
• Data trending and export for system analysis
• Standard 4CT/4VT configuration for versatile protection schemes

Technical Specifications

Applications

• Power system protection — overcurrent, differential, and distance protection
• Transformer protection — current and voltage monitoring
• Generator protection — phase and ground fault detection
• Feeder protection — load monitoring and fault identification
• Substation automation — SCADA integration and data acquisition

Compatibility

The UR-8AH is compatible with older UR CPU modules (UR-9A, UR-9C, UR-9D) running firmware 3.5x or earlier. For newer CPU modules, consider upgraded CT/VT modules with enhanced diagnostics. Always pair new CT/VT modules with new CPUs to avoid hardware mismatch errors.

Installation Guide

1. Power Down: Completely de-energize the UR relay chassis. Never install or remove modules while energized.
2. ESD Protection: Wear a grounded ESD wrist strap before handling the module.
3. Slot Verification: Confirm the CT/VT slot position per the relay manual.
4. Module Insertion: Slide the UR-8AH into the designated slot, aligning the rear connector with the backplane.
5. Secure Mounting: Tighten the faceplate retention screws.
6. Wiring: Connect CT and VT secondary wiring per the UR series wiring diagram. Ensure secondary windings are properly grounded.
7. Configuration: Power on and configure CT/VT ratios and settings via EnerVista UR Setup software.

FAQ

Q: What does the "8A" order code signify?
A: The "8A" designates a standard CT/VT module with 4 CT and 4 VT inputs.

Q: Is the UR-8AH compatible with newer UR CPUs?
A: The UR-8AH is designed for older CPUs (UR-9A, UR-9C, UR-9D) with firmware 3.5x or earlier. For newer systems, consider CT/VT modules with enhanced diagnostics.

Q: Why is secondary winding grounding important?
A: Grounding the secondary winding of CTs and VTs is a safety requirement that protects operators from high voltage and prevents equipment damage.

Q: What is the maximum number of CT/VT modules per chassis?
A: The UR platform allows a maximum of 3 CT/VT modules per chassis, supporting up to 6 sets of three-phase voltages and currents.

Selection Tips

• Choose UR-8AH for standard 4CT/4VT applications with older UR CPUs.
• For enhanced diagnostics, consider the UR-8LH or UR-8NH.
• For sensitive ground fault protection, consider the UR-8G, UR-8J, UR-8M, or UR-8R modules.
• Always verify CPU and firmware compatibility before ordering.

Ordering Information