Technical Specification: Gas-Insulated Switchgear (GIS)
This section outlines the technical specifications for Gas-Insulated Switchgear (GIS) used in high-voltage substations. The GIS technology combines compact design, high reliability, and superior safety, making it suitable for modern power systems.
1. General Requirements
- Application: High-voltage power transmission and distribution.
- Standards Compliance:
- IEC 62271-203 (GIS for rated voltages above 52 kV).
- IEEE C37.122 (GIS standards for design, testing, and performance).
- ISO 14001 for environmental considerations.
- Voltage Ratings: 72.5 kV to 800 kV.
- Frequency: 50 Hz / 60 Hz.
- Ambient Conditions:
- Temperature: -25°C to +55°C.
- Humidity: Up to 95% non-condensing.
2. GIS Configuration
- Single Busbar: For standard applications requiring high reliability.
- Double Busbar: For critical systems with enhanced operational flexibility.
- Hybrid Configurations: Combining GIS and air-insulated switchgear (AIS) for cost-effectiveness.
3. Key Components and Features
3.1 Enclosures
- Material: High-grade, corrosion-resistant aluminum or stainless steel.
- Insulation Medium: SF6 gas (Sulfur Hexafluoride) for superior dielectric strength.
- Design: Hermetically sealed, modular design for ease of maintenance.
3.2 Circuit Breakers
- Type: SF6 gas-insulated, single-pressure or double-pressure mechanism.
- Operation: Spring or hydraulic mechanism.
- Interrupting Capacity: Up to 80 kA.
- Closing Time: ≤ 60 ms.
3.3 Disconnectors and Earthing Switches
- Disconnectors: Motor-operated, ensuring isolation for maintenance.
- Earthing Switches: Fast-closing type for system grounding.
3.4 Current Transformers (CTs)
- Type: Inductive or optical.
- Accuracy Class: 0.2S for metering and protection.
- Overcurrent Capacity: Up to 120% of rated current.
3.5 Voltage Transformers (VTs)
- Type: Capacitive or electromagnetic.
- Accuracy: Class 0.5 for measurement.
3.6 Busbars
- Design: Single-phase encapsulated.
- Material: Copper or aluminum.
- Short-Circuit Rating: ≥ 50 kA for 3 seconds.
3.7 SF6 Gas System
- Gas Purity: ≥ 99.9%.
- Gas Leakage Rate: ≤ 0.1% per year.
- Monitoring: Continuous gas pressure and density monitoring systems.
4. Control and Protection Systems
- Control Panels: Microprocessor-based panels for local and remote operation.
- Protection Relays: Integrated with overcurrent, differential, and distance protection schemes.
- SCADA Compatibility: Ensures seamless integration with supervisory systems.
5. Performance Specifications
- Dielectric Strength: ≥ 5 times the operating voltage.
- Temperature Rise: ≤ 40°C under rated load.
- Partial Discharge: < 5 pC.
- Mechanical Endurance: ≥ 10,000 operations for circuit breakers.
6. Environmental Considerations
- SF6 Management:
- Use of gas recovery and recycling systems to minimize environmental impact.
- Leak-proof design to adhere to ISO 14001 standards.
- Noise Emission: ≤ 60 dB(A) at 1 meter.
7. Testing and Quality Assurance
Factory Acceptance Tests (FAT)
- Dielectric tests.
- Partial discharge tests.
- Gas leakage tests.
- Functional tests for control and protection systems.
Site Acceptance Tests (SAT)
- Insulation resistance measurement.
- High-voltage withstand tests.
- System integration tests with SCADA.
8. Installation and Maintenance
- Installation: Modular assembly allowing quick and efficient setup.
- Maintenance:
- Periodic inspection of gas pressure and density.
- Calibration of protection systems every 5 years.
- Visual inspection of components every 2 years.
9. Safety Features
- Arc Fault Protection: Internal arc classification up to IAC A FLR.
- Emergency Shutdown Systems: Manual and automatic shut-off mechanisms.
- Interlocks: Prevent unauthorized access to energized components.
10. Documentation and Training
- Documentation: Detailed user manuals, wiring diagrams, and maintenance schedules.
- Training: On-site training for operators and maintenance personnel.
11. Warranty and Support
- Warranty: Minimum of 5 years.
- Support: 24/7 technical assistance and spare parts availability.
The above specifications ensure that the GIS meets the highest standards of reliability, efficiency, and safety, suitable for modern high-voltage power systems.
Download Timer
