GE UR Series RHH Modules — GE UR RHH Universal Relay Digital I/O Module

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), is a modular protection and control platform deployed across critical heavy-industry infrastructure worldwide — including petrochemical refineries, nuclear generating stations, offshore platforms, and high-voltage transmission substations. The UR platform's slot-based chassis architecture allows field engineers to configure relay functionality by populating specific module types into a standardized 19-inch rack enclosure. The RHH module occupies the Digital I/O function within this architecture, providing hardwired contact input and output capacity essential for trip, alarm, and interlock circuits. Installed base spans multiple continents with documented deployments in IEC 61850-compliant substations and legacy SCADA environments alike.

The Evolution of UR Series Architecture

The UR platform was introduced in the late 1990s as a successor to GE Multilin's SR Series relays, consolidating protection, metering, control, and communications into a single modular chassis. Early UR hardware (firmware generation 1.x–3.x) used proprietary backplane communication and supported RS-485 serial interfaces (DNP3, Modbus RTU). The mid-generation transition (firmware 4.x–5.x) introduced IEC 61850 GOOSE messaging via the 9E Ethernet module and expanded the I/O module count per chassis. Current-generation UR hardware (firmware 7.x) supports IEEE 1588 precision time protocol, redundant Ethernet, and cybersecurity hardening per NERC CIP standards.

Compatibility constraints are a persistent operational challenge: early-generation CPU modules (9G5, 9G6) are not firmware-compatible with later-generation I/O modules without a full chassis upgrade. The RHH Digital I/O module is compatible across mid-to-late UR generations but requires verification of backplane revision before substitution. Engineers maintaining mixed-generation fleets must cross-reference the UR Order Code matrix published in GE document GEK-113000.

UR Series Full Catalog & Functionalities (SKU List)

CPU / Main Processing Modules

• 9G5: Early-generation CPU module; supports DNP3/Modbus serial; no IEC 61850 native support.
• 9G6: Mid-generation CPU; adds IEC 61850 GOOSE; compatible with UR firmware 4.x–5.x chassis.
• 9G7: Current-generation CPU; IEEE 1588 PTP; NERC CIP cybersecurity hardening; dual Ethernet ports.

Digital I/O Modules

• RHH: Universal Relay Digital I/O Module; 8 contact inputs, 8 output relays; hardwired trip/alarm/interlock circuits.
• RHA: Digital I/O module variant; 16 contact inputs; optimized for high-density input applications.
• RHB: Digital I/O module; 8 inputs / 4 high-current output contacts; rated for motor control applications.
• RHC: Digital I/O module; 4 fast-operate output contacts; <8 ms operate time for high-speed trip circuits.
• RHD: Digital I/O module; mixed I/O; 6 inputs / 6 outputs; general-purpose protection relay applications.

Analog I/O Modules

• 9A1: AC analog input module; 4 current / 4 voltage channels; 16-bit ADC; for current differential protection.
• 9A2: AC analog input module; 8 current channels; bus differential and transformer protection applications.
• 9A3: DC analog input module; 4–20 mA / 0–10 V inputs; process variable monitoring integration.

Communications Modules

• 9E: Ethernet communications module; 10/100 Base-T; IEC 61850 Ed.1/Ed.2; DNP3 over TCP/IP.
• 9E2: Dual-port Ethernet module; redundant network topology support; RSTP/PRP/HSR protocols.
• 9F: Fiber-optic communications module; ST connector; inter-relay direct fiber channel for POTT/PUTT schemes.
• 9S: Serial communications module; RS-232/RS-485; Modbus RTU / DNP3 serial for legacy SCADA integration.

Power Supply Modules

• 9P1: DC power supply module; 24–48 VDC input; for substation battery-backed DC bus applications.
• 9P2: DC power supply module; 110–250 VDC / 100–240 VAC universal input; standard substation supply.
• 9P3: Redundant power supply module; dual-feed input; hot-swap capable; for critical continuous-operation sites.

Transducer / Specialty Modules

• 9T1: Transducer input module; RTD / thermocouple inputs; transformer thermal overload protection.
• 9T2: Transducer output module; 4–20 mA analog outputs; metering retransmission to DCS/SCADA.

Sourcing Hard-to-Find & Obsolete UR Series Parts

The GE UR Series entered its mature lifecycle phase in the 2010s. GE Grid Solutions has progressively issued end-of-life notices for early-generation CPU and I/O modules, including the 9G5, 9G6, RHA, and RHB variants. OEM new-stock availability for these part numbers through standard distribution channels is effectively exhausted. DriveKNMS maintains a dedicated inventory of tested surplus and refurbished UR Series modules sourced from decommissioned substation equipment, controlled plant shutdowns, and authorized liquidation programs. All units are catalogued by part number, firmware revision, and hardware revision code. For customers requiring long-term maintenance contracts covering UR Series assets beyond OEM support windows, DriveKNMS provides multi-year supply agreements with guaranteed unit availability and lead-time commitments. Customers operating under NERC CIP or IEC 62443 compliance frameworks can request documentation packages including test records and chain-of-custody certificates.

Quality Control for the UR Series Range

UR Series modules present specific test challenges due to their backplane-dependent communication architecture. DriveKNMS employs a dedicated UR chassis test bench replicating the standard 19-slot UR enclosure with active CPU, power supply, and communications modules. Each Digital I/O module (including RHH variants) undergoes the following verification sequence: (1) backplane slot insertion and firmware handshake confirmation; (2) individual contact input actuation test across all 8 input channels using calibrated 24 VDC / 125 VDC test signals; (3) output relay coil energization and contact continuity verification for all output channels; (4) operate-time measurement for fast-operate contacts against GE specification tolerances; (5) insulation resistance test at 500 VDC between contact circuits and chassis ground; (6) 48-hour powered burn-in at ambient temperature. Modules failing any stage are quarantined and not returned to inventory. Test records are retained for a minimum of 7 years and are available to customers upon request.

For sourcing inquiries, technical specifications, or long-term supply agreements for GE UR Series modules:

• Email: sale@driveknms.com
• WhatsApp: +86 18359293191
• Web: driveknms.com

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.