Description
GE 12STV11A1A
Technical Specifications
- Part Number: 12STV11A1A
- Function: Harmonic Restraint / Static Overexcitation
- Pickup Adjustment Range: 1.8-2.5 V/Hz
- Time Delay: 0.5-15.0 seconds adjustable
- Input Voltage: 120 VAC / 60 Hz
- Type: STV Series Static Relay
- Relay Type: Static overexcitation protection relay
Key Features
- Harmonic restraint function to prevent false tripping during system transients
- Adjustable pickup range of 1.8-2.5 V/Hz for flexible protection settings
- Adjustable time delay from 0.5 to 15.0 seconds for coordination with other protective devices
- Static electronic design for high reliability and fast response
- Designed for generator and transformer overexcitation protection
- 120 VAC / 60 Hz operating voltage
Application Scenarios Power generation plants, generator protection systems, transformer protection schemes, utility substations, industrial cogeneration facilities, hydroelectric power stations
Performance Parameters
- Pickup Range: 1.8-2.5 V/Hz
- Time Delay: 0.5-15.0 seconds
- Operating Voltage: 120 VAC, 60 Hz
- Function: Harmonic restraint overexcitation protection
Material Composition Industrial-grade electronic components housed in a robust relay enclosure. Static electronic design eliminates mechanical wear associated with electromechanical relays. Components selected for long-term reliability in power system environments.
Structural Characteristics Standard relay form factor designed for panel mounting in switchgear and control cabinets. The relay features a compact design suitable for integration into existing protection schemes. Terminal connections are provided for voltage sensing inputs, output contacts, and auxiliary power.
Working Principle The 12STV11A1A continuously monitors the voltage-to-frequency ratio (V/Hz) at the generator terminals. When the V/Hz ratio exceeds the set pickup value (1.8-2.5 V/Hz), the relay initiates a timing sequence. If the condition persists beyond the adjustable time delay (0.5-15.0 seconds), the relay operates to trip the generator field breaker or activate an alarm. The harmonic restraint feature analyzes the harmonic content of the voltage signal to distinguish between true overexcitation (characterized by low harmonic content) and voltage transformer saturation or other transient conditions (characterized by high harmonic content).
Installation Requirements The relay must be installed by qualified personnel in accordance with electrical safety standards. Mounting should be in a clean, dry environment within the specified temperature range. Proper voltage transformer connections are essential for accurate V/Hz measurement. The relay should be wired into the generator protection scheme with appropriate isolation and fusing.
Usage Notes Regular calibration and testing of the pickup and time delay settings are recommended to ensure continued accurate operation. The harmonic restraint settings should be verified during commissioning and after any system modifications. Periodic functional testing using injection test equipment ensures the relay will operate correctly during actual fault conditions. The relay should be de-energized before any maintenance work is performed.
