Description
| Product model | SR469-P5-HI-A20-H |
| Manufacturer | GE Vernova (formerly GE Grid Solutions / Alstom Grid) |
| Product category | Multifunction Generator Protection Relay |
| Core function | Comprehensive generator and generator-transformer unit protection |
| Current inputs | 1 A or 5 A nominal; HI version with high-input impedance (≥100 kΩ) for reduced burden on CTs |
| Voltage inputs | Up to 120 V LN / 208 V LL; supports VT monitoring with configurable scaling |
| Output relays | A20-H configuration: 20 standard SPDT + 4 high-energy (10 A, 250 VDC) output contacts |
| Communication interfaces | Dual Ethernet (IEC 61850-9-2LE, GOOSE, MMS), RS-485 (Modbus RTU/ASCII), USB, IRIG-B input |
| Power supply | 88–264 VAC or 125–370 VDC, universal wide-range input |
| Frequency range | 45–65 Hz, auto-sensing for 50/60 Hz systems |
| Environmental operating range | -30°C to +70°C (-22°F to 158°F), 5–95% RH (non-condensing) |
| Installation method | Panel-mounted (19” rack or switchgear cubicle), 14.8” (376 mm) width |
| Standards compliance | IEC 60255, IEEE C37.90, IEC 61850, NEMA, UL |
Product introduction
The SR469-P5-HI-A20-H GE is a state-of-the-art digital multifunction generator protection relay engineered for the comprehensive protection, monitoring, and control of medium and large-scale generators in utility, industrial, and renewable energy applications. As part of GE’s renowned SR Series platform, the SR469-P5-HI-A20-H integrates advanced protection algorithms, precise metering, and robust communication capabilities into a single, compact unit. It is specifically designed to safeguard critical generation assets against electrical faults such as differential faults, stator earth faults, overcurrent, loss of excitation, reverse power, under/over voltage, and out-of-step conditions.
Tailored for high-availability environments, the SR469-P5-HI-A20-H GE features the HI (High-Impedance Input) configuration, which minimizes the loading effect on current and voltage transformers—ideal for long cable runs commonly found in power plant switchyards. The A20-H output configuration provides 20 standard control relays plus 4 high-energy contacts capable of directly driving large trip coils and auxiliary relays, eliminating the need for external amplifiers. With native support for IEC 61850, GOOSE messaging, Modbus, and IRIG-B time synchronization, the SR469-P5-HI-A20-H seamlessly integrates into modern digital substations and SCADA systems, making it a cornerstone of smart grid and digital power plant architectures.
SR469-P5-HI-A20-H GE
Main Features and Advantages
Advanced generator protection algorithms:
The SR469-P5-HI-A20-H GE delivers unparalleled protection accuracy with sophisticated functions such as 10th harmonic restraint for inrush stabilization, voltage-dependent overcurrent (VDOC), load encroachment detection, and out-of-step tripping with blinder logic. These features ensure reliable operation during transient grid disturbances while preventing nuisance trips, a critical requirement for base-load and peaking power plants.
High-impedance input technology:
The HI variant of the SR469-P5-HI-A20-H significantly reduces the burden on CTs and VTs, enhancing measurement accuracy and extending the life of primary instrumentation. This is especially valuable in retrofit projects where existing transformer ratios and cable lengths cannot be modified. The high-input impedance design also improves signal integrity over long distances, reducing errors due to voltage drop.
Robust communication and interoperability:
Equipped with dual Ethernet ports supporting IEC 61850-9-2LE and GOOSE, the SR469-P5-HI-A20-H enables fast, secure, and deterministic peer-to-peer communication in digital substations. It supports full station bus integration with protection, automation, and SCADA systems, enabling seamless data exchange without protocol gateways. Additional interfaces like Modbus, USB, and IRIG-B ensure backward compatibility and simplified commissioning.
Flexible and scalable output configuration:
With the A20-H relay package, the SR469-P5-HI-A20-H offers exceptional control flexibility. The 20 standard outputs handle alarms, interlocks, and status signals, while the four high-energy (10 A) contacts are designed for direct tripping of high-capacity circuit breakers—crucial in high-voltage generator applications. This eliminates external relay panels, saving space and reducing wiring complexity.
Rugged design for harsh environments:
Housed in a reinforced metal enclosure with EMI/RFI shielding, the SR469-P5-HI-A20-H operates reliably in extreme temperatures (-30°C to +70°C) and high-humidity environments. It meets stringent electromagnetic compatibility and safety standards, ensuring long-term stability in power plants, offshore platforms, and remote generating stations.
Application Areas
The SR469-P5-HI-A20-H GE is extensively deployed in thermal power plants, including combined-cycle gas turbines (CCGT), coal-fired units, and cogeneration facilities, where generator reliability is paramount. In these environments, the SR469-P5-HI-A20-H continuously monitors stator differential currents, detects high-resistance earth faults via third-harmonic voltage, and prevents damage during loss-of-field conditions. Its out-of-step protection function is critical for maintaining grid stability during system faults or sudden load changes.
In hydroelectric stations, the SR469-P5-HI-A20-H provides precise synchronization and anti-motoring protection, ensuring turbines are not driven as motors during low-load conditions. The relay’s ability to interface with governor and excitation systems via digital outputs enables coordinated control strategies, improving plant efficiency and response time.
Renewable energy installations, such as wind farms and large solar PV plants with synchronous condensers, also benefit from the SR469-P5-HI-A20-H. It protects the generator during grid faults and supports islanding detection, ensuring safe reconnection after outages. Its IEC 61850 compliance makes it ideal for centralized monitoring in hybrid power plants integrating multiple generation sources.
Additionally, the SR469-P5-HI-A20-H is used in industrial captive power plants, offshore oil & gas platforms, and data center backup generators, where uninterrupted power supply is critical. Its high-input impedance design is particularly advantageous in offshore and remote locations with long cable runs between switchyard and control room. Whether protecting a 50 MW gas turbine or a 300 MW steam generator, the SR469-P5-HI-A20-H delivers unmatched reliability and intelligence.
Related Products
SR469-P5-LP-A10: Base model with low-power inputs and 10 output relays; suitable for smaller generators or cost-sensitive projects.
SR745: GE’s feeder protection relay that complements the SR469-P5-HI-A20-H in generator-transformer unit protection schemes.
SR751: Motor protection relay often used alongside the SR469-P5-HI-A20-H in plant auxiliary systems.
SR469-P5-HI-A30-H: Higher-end variant with 30 standard + 4 high-energy outputs for ultra-complex control logic.
L90 Line Differential Relay: Used in conjunction with the SR469-P5-HI-A20-H for transmission line protection in generator step-up (GSU) configurations.
GE Multilin S60: Integrated protection and control platform that can host SR469-P5-HI-A20-H functionality in a system-level solution.
UR Series Configuration Tool: Software suite required for configuring, commissioning, and monitoring the SR469-P5-HI-A20-H.
GE ION Enterprise: SCADA and power management system that integrates data from the SR469-P5-HI-A20-H for enterprise-level monitoring.
SR469-P5-HI-A20-H GE
Installation preparation
Before installing the SR469-P5-HI-A20-H GE, ensure the switchgear panel is de-energized and locked out per local safety regulations. Verify that the panel cutout dimensions (376 mm width) and panel thickness are compatible. Use shielded, twisted-pair cables for all analog and communication wiring to minimize noise. For the HI inputs, confirm CT/VT secondary ratings and avoid paralleling CTs unless properly calculated. Connect the power supply within the 88–264 VAC or 125–370 VDC range and ensure proper grounding of the chassis. After physical installation, use the UR Setup software to verify firmware version and configure protection settings.
Maintenance suggestions:
Perform periodic functional tests on the SR469-P5-HI-A20-H using a secondary injection test set to validate relay operation and trip circuit integrity. Check event logs and oscillography data regularly to detect incipient faults. Keep firmware updated via secure USB or Ethernet connection. Inspect terminal blocks for loose connections annually, especially in high-vibration environments. The SR469-P5-HI-A20-H requires no routine calibration due to its solid-state design, but verify time synchronization (IRIG-B) monthly for accurate event sequencing.
