Transformer Protection Relay GE Multilin T35EOOHCH Series

Technical Overview

The T35E00HCH is a premier digital protection system within the GE Multilin Universal Relay (UR) family, specifically optimized for the management of power transformers, autotransformers, and generator step-up (GSU) units. This microprocessor-based relay provides high-speed, secure differential protection capable of managing up to six sets of current transformer (CT) inputs. Its architectural versatility allows for the protection of complex two-winding and three-winding configurations, ensuring sub-cycle fault detection. By integrating advanced restraint algorithms, the T35E00HCH effectively differentiates between internal faults and magnetizing inrush or overexcitation, preventing nuisance trips while maintaining maximum sensitivity for internal winding insulation failures.

Detailed Technical Data

The T35E00HCH hardware and firmware are designed to meet the following high-availability specifications:

• Manufacturer: GE Multilin (General Electric)

• Model Configuration: T35E00HCH (Universal Relay Platform)

• Core Protection Functions:

• Restricted Earth Fault (REF) and Transformer Differential (87T)

• Phase, Ground, and Neutral Overcurrent (50/51, 50N/51N)

• Under/Over-frequency and Voltage elements

• Thermal Overload monitoring

• CT Input Capacity: Supports up to 6 sets of CTs for multi-winding protection

• Communication Stack:

• Primary Protocols: IEC 61850 (Editions 1 & 2), Routable GOOSE (R-GOOSE)

• Legacy Integration: Modbus RTU/TCP, DNP 3.0, and EGD

• User Interface: 7-inch integrated full-color graphical HMI with local control mimics

• Security Suite: Embedded CyberSentry™ technology (NERC CIP and IEEE 1686 compliant)

• Operating Range: Industrial-grade endurance from -40°C to +70°C

• Fault Diagnostics: Integrated COMTRADE waveform capture and sequence of events (SOE) logging

Digital Substation Integration and Automation

The T35E00HCH is a cornerstone of modern digital substation architecture. Utilizing high-speed peer-to-peer GOOSE messaging, the relay can coordinate with other UR-series devices for bus interlocking and breaker failure schemes without physical hardwiring. Its FlexLogic™ engine enables engineers to program complex automation sequences directly within the relay, reducing the need for external auxiliary timers and logic controllers. For critical infrastructure, the integrated cybersecurity features provide encrypted access and detailed audit trails, ensuring the transformer protection remains shielded from unauthorized network interference.