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SF6 Gas-Insulated Ring Main Unit Equipment

SF6 Gas-Insulated Ring Main Unit Equipment

UN7-72.5-630-1250-31.5kA gas-insulated ring main unit, designed and manufactured in accordance with GB and IEC standards, features a fully insulated and fully sealed structure. It is suitable for harsh environments such as those characterized by pollution, salt spray, humidity, and high altitudes, and offers multiple configurations to meet even more demanding requirements. Applied to 66kV voltage-rated offshore and onshore wind turbine generator transformers; 66kV voltage-level grid-connected offshore and onshore energy storage and photovoltaic box-type substations; Substations and distribution ring network power supply locations connected to a 66kV voltage grid.

Product Features


· This product is designed and manufactured in compliance with GB and IEC standards.
· Manufactured with a structural design featuring vacuum arc-extinguishing and all-insulated by SF6 gas;
· The air chamber boasts an IP67 protection rating and requires no inflation or refilling throughout the installation process and its entire service life.
· The product meets requirements for altitudes of 5,000 meters and below;
· Suitable for operation in environments with industrial pollution, salt spray, and high humidity; meets C3 standard on land and C4 standard at sea.

Operating Environment Conditions


· For outdoor or indoor use
· Altitude: ≤5000m (Special note required if the operating altitude of the equipment exceeds 2000m);
· Ambient temperature: Maximum temperature +65℃, minimum temperature -40℃, average value within 48 hours ≤35℃;
· Environmental humidity: Suitable for all humid environments;
· Pollution degree: Level 4 pollution;
· Corrosion resistance class: Offshore C4H;
· Seismic resistance level: AG5 (horizontal acceleration 0.3g, vertical acceleration 0.15g);
· Electromagnetic interference: The amplitude of electromagnetic interference induced in the secondary system ≤ 1.6 kV;
· Installation environment: There should be no explosive or corrosive gases in the surrounding air, and the installation location must be free from frequent, severe vibrations or shocks. Note: If the operating environment exceeds the conditions specified above, please consult with the company to arrange a customized solution.

Applicable Standards


· GB/T 7674-2020 Gas-insulated metal-enclosed switchgear with rated voltage of 72.5 kV and above
· IEC62271-203:2011 Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV
· IEC60694-2002 Common Technical Requirements for High-Voltage Switchgear and Control Equipment
· GB/T3906-2020 and IEC 62271-200:2011 3.6kV~40.5kV AC metal-enclosed switchgear and control equipment
· GB/T11022-2020 and IEC 62271-1:2017—Common Technical Requirements for High-Voltage Switchgear and Control Equipment
·GB/T1984-2014 and IEC62271-100:2017 – AC High-Voltage Circuit Breakers
· GB/T4208-2017 and IEC60529: Enclosure Protection Ratings (IP Codes)
· GB/T16927.1~2-2013 High-Voltage Test Techniques

· GB/T3309-1989
· GB/T4473-2018
· GB/T5582-1993 Mechanical Tests for High-Voltage Switchgear at Ambient Temperature—Synthetic Testing for High-Voltage AC Circuit Breakers—Contamination Levels of External Insulation for High-Voltage Power Equipment
· GB/T11023-2018 Test Method for Gas Sealing of Sulfur Hexafluoride in High-Voltage Switchgear
· DL/T402-2017 Technical Specifications for Ordering High-Voltage AC Circuit Breakers
· DL/T486-2021 Technical Specifications for Ordering High-Voltage AC Disconnect Switches and Earthing Switches
· DL/T403-2017 Technical Specifications for Ordering 12kV to 40.5kV High-Voltage Vacuum Circuit Breakers
· DL/T404-2018 3.6kV~40.5kV AC Metal-Enclosed Switchgear and Control Equipment
· DL/T593-2016 Common Technical Requirements for Standards of High-Voltage Switchgear and Control Equipment

Technical Specifications


Name Unit Switchgear and Circuit Breaker Parameters
Rated voltage kV 72.5
Rated frequency Hertz 50
Rated current A 630/1250
 

Rated insulation level

Power-frequency withstand voltage (phase-to-phase, phase-to-ground, vacuum interrupter contacts) kV 160
Power-frequency withstand voltage (isolated break) kV 160+42
Power-frequency withstand voltage (auxiliary and control circuits) kV 2
Lightning impulse withstand voltage (phase-to-phase, phase-to-ground, vacuum interrupter) kV 380
Lightning Impulse Withstand Voltage (Isolation Break) kV 350 + 60
Rated short-circuit breaking current kA 31.5
Rated short-circuit breaking operations Next 30
Rated short-circuit making current (main switch/fault-making earthing switch) kA 80/80
Short-time withstand current and duration (main circuit + earthing switch, earthing connection) kA/s 31.5/4, 27.5/2
Rated peak withstand current (main circuit + earthing switch, earthing connection) kA 80, 69.6
Circuit breaker mechanical life Next 10000
SF6 rated pressure Rated inflation pressure (gauge pressure at 20°C) MPa 0.12
Minimum inflation pressure (gauge pressure at 20℃) MPa 0.08
Protection rating An energized electrical box   IP67
Cabinet body, cable compartment, cover plate   IP5X
Annual relative leakage rate of gas %/year s0.01
Mechanical Operation Sequence   0-0.3s-CO-180s-CO
Expected service life Year 30
Busbar/Grounding busbar (copper bar)   240 mm²
Structural Type   Direct-acting
Rated voltage kV 72.5
Rated frequency Hertz 50
Rated current A 630/1250
 

Rated insulation level

Power-frequency withstand voltage (phase-to-phase, phase-to-ground) kV 160
Power-frequency withstand voltage (isolated break) kV 160+42
Lightning impulse withstand voltage (phase-to-phase, phase-to-ground) kV 380
Lightning Impulse Withstand Voltage (Isolation Break) kV 350 + 60
Short-time withstand current and duration (main circuit + earthing switch, earthing connection) kA/s 31.5/4, 27.5/2
Rated peak withstand current (main circuit + earthing switch, earthing connection) kA 80, 69.6
Mechanical life Next 3000
Expected service life Year 30
Busbar/Grounding busbar (copper bar)   240 mm²
Short-time withstand current and duration (main circuit + earthing switch, earthing connection) kA/s 31.5/2
Rated peak withstand current (main circuit + earthing switch, earthing connection) kA 80, 69.6
Mechanical life Next 3000
Expected service life Year 30