GE UR Series Modules

Technical Dossier

Product Details And Specifications

GE UR Series: Comprehensive Module Range and Technical Overview

The GE UR (Universal Relay) Series, developed by GE Grid Solutions (formerly GE Multilin), represents one of the most widely deployed digital protection relay platforms in global heavy industry. Installed across chemical processing plants, nuclear power stations, petroleum refineries, offshore platforms, and high-voltage transmission substations, the UR Series has established a dominant position in mission-critical protection applications where relay coordination, fault recording, and communications redundancy are non-negotiable operational requirements. The platform's modular hardware architecture allows end users to configure relay functionality precisely to the protection scheme required — from single-function feeder protection to complex multi-function transformer and generator protection — without replacing the base chassis. This flexibility has made the UR Series the relay of choice for utilities and industrial operators managing aging infrastructure alongside modern SCADA and IEC 61850 networks.

The Evolution of UR Series Architecture

The UR platform was introduced in the late 1990s as GE Multilin's response to the industry's transition from electromechanical and solid-state relays to fully numerical, microprocessor-based protection. The first-generation UR chassis established the 19-inch rack-mount form factor and the modular slot-based I/O philosophy that remains the platform's defining characteristic today.

Early UR firmware (pre-4.0x) operated on a proprietary real-time OS with limited IEC 61850 support. From firmware 5.0x onward, GE introduced full GOOSE messaging and MMS protocol compliance, enabling the UR Series to integrate natively into IEC 61850 station bus architectures. The transition to firmware 7.xx brought enhanced cybersecurity features aligned with NERC CIP requirements, including role-based access control and encrypted communications — a critical development for utility operators subject to regulatory compliance mandates.

Hardware revisions followed a parallel trajectory. The original CPU modules (e.g., UR6FH, UR7FH) were succeeded by higher-performance variants with expanded memory and faster sampling rates. The introduction of the 9-slot chassis (e.g., UR9xx platform) extended the I/O capacity for complex protection schemes requiring simultaneous analog, digital, and communications modules. Compatibility between chassis generations is constrained: modules from the 6-slot and 8-slot chassis families are not interchangeable with 9-slot variants without engineering review. This is a critical consideration for maintenance teams sourcing replacement modules for installed base equipment.

As of 2026, the UR Series is in a mature/sustained phase. GE Grid Solutions continues to supply firmware updates and hardware replacements, but the platform is no longer the primary development focus — that role has shifted to the UR-series successor platforms. For operators with long-term installed base commitments, lifecycle extension through certified spare parts sourcing is the primary maintenance strategy.

UR Series Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly deployed modules within the GE UR Series platform. Modules are classified by functional category.

CPU & Main Processing Modules

• UR6FH: 6-slot chassis CPU module, dual Ethernet, IEC 61850 GOOSE support
• UR7FH: 7-slot chassis CPU, enhanced memory, firmware 7.xx compatible
• UR8FV: 8-slot chassis CPU module, dual-redundant power input, high-speed sampling
• UR9FH: 9-slot chassis CPU, expanded I/O addressing, NERC CIP firmware support
• UR6GH: 6-slot CPU, next-generation variant with extended flash storage

Analog Input Modules (AI)

• UR8AI: 8-channel analog input, 4–20 mA, for current/voltage transducer interfacing
• UR6AI: 6-slot analog input module, CT/VT secondary input, 16-bit ADC resolution
• UR9AI: 9-slot analog input, simultaneous 3-phase current and voltage measurement
• URTAI: Transducer analog input module, RTD and thermocouple compatible

Digital Input Modules (DI)

• UR8DI: 8-slot digital input, 24 optically isolated inputs, 24/48/125 VDC selectable
• UR6DI: 6-slot digital input module, 16 inputs, wet/dry contact configurable
• UR9DI: 9-slot digital input, 32-channel, high-speed event capture (<1 ms resolution)

Digital Output / Relay Output Modules (DO)

• UR8DO: 8-slot digital output, 16 Form-A relay contacts, 30 A make rating
• UR6DO: 6-slot relay output module, 8 Form-C contacts, trip-rated
• UR9DO: 9-slot digital output, 24 outputs, mixed Form-A/C configuration

Communications & Adapter Modules

• URDSP: Direct serial port module, RS-232/RS-485, DNP3 and Modbus RTU
• URFIB: Fiber optic inter-relay communications module, IEEE C37.94 compatible
• URIRIG: IRIG-B time synchronization module, GPS-disciplined timing input

Power Supply Modules

• UR8PS: 8-slot power supply, 125/250 VDC input, redundant output rails
• UR6PS: 6-slot power supply module, 24–250 VDC wide-range input

Sourcing Hard-to-Find & Obsolete UR Series Parts

DriveKNMS maintains a dedicated inventory program for GE UR Series modules that have reached end-of-active-production status. For operators running UR platform relays in substations or industrial facilities with 10–25 year operational horizons, the ability to source verified replacement modules — particularly CPU boards, analog input cards, and communications adapters — is a direct operational risk factor.

Our sourcing process for obsolete UR Series parts includes: direct procurement from decommissioned substation equipment, certified refurbishment of pulled units, and cross-referencing of GE Multilin part numbers against current GE Grid Solutions equivalents where form-fit-function substitution is documented. All modules are supplied with full traceability documentation. For time-critical plant maintenance windows, DriveKNMS offers priority allocation from bonded stock.

Quality Control for the UR Series Range

The GE UR Series presents specific quality verification challenges due to its backplane bus architecture and the tight coupling between CPU firmware and I/O module hardware revisions. DriveKNMS applies a structured test protocol to all UR Series modules prior to dispatch:

• Backplane bus integrity check: Each module is seated in a reference chassis and the inter-module communication bus is verified under simulated load conditions. Modules exhibiting intermittent bus errors or address conflicts are rejected.
• Analog channel calibration verification: AI modules are tested against NIST-traceable current and voltage references. Channel-to-channel isolation is measured and must meet OEM specification (>500 MΩ at 500 VDC).
• Relay output contact resistance measurement: DO module contacts are cycled 100 times and contact resistance is measured at each Form-A and Form-C output. Contacts exceeding 100 mΩ are flagged for rejection.
• Firmware compatibility matrix check: CPU modules are verified against the published GE UR firmware compatibility matrix to confirm the installed firmware version is consistent with the hardware revision. Mismatched combinations are reflashed or documented for customer awareness.
• Communications port functional test: Ethernet, serial, and fiber ports are tested using protocol analyzers for DNP3, Modbus, and IEC 61850 frame integrity.