Guide to Load Switch Selection and Distribution Network Application

2025-05-20 15:00:46

1、 The core role of Load switches in distribution networks 1. System segmentation and fault isolation -By disconnecting the load current (≤ 630A), quickly isolate the faulty section of the line and reduce the power outage range (MTTR shortened to within 30 minutes).   -Suitable for 10kV/12kV distribution network, combined with Fuses to achieve short-circuit protection (with a breaking capacity of up to 20kA).   2. Equipment protection and operational safety -Design with visible fracture surface to ensure physical isolation during maintenance (fracture distance>200mm).   -Mechanical interlocking function prevents misoperation (such as FN12-12D load switch).  

3. Flexible networking and automation support -The core components of the ring main unit (such as HXGN17 type) support dual power switching.   -Integrated electric operating mechanism, compatible with distribution automation system (DA/FA function).   2、 Key selection points and technical parameters 1. Voltage level matching -Select 12kV rated voltage (such as FKN18-12) for the 10kV system, with a 20% insulation margin reserved.   2. Current capacity and breaking capacity -Conventional routes: 400A (residential area), 630A (industrial area).   -Frequent operation scenario: Choose permanent magnet mechanism (mechanical life>10000 times).   3. Environmental adaptability design -Coastal areas: IP65 protection+stainless steel casing (salt spray test>1000 hours).   -High cold area: -40 ℃ low-temperature lubricating grease+silicone rubber seal.   4. Intelligent function expansion -Built in wireless temperature measurement (accuracy ± 1 ℃) and partial discharge monitoring sensor.   -Support 4G/5G communication and connect to the distribution IoT platform.   3、 Typical application scenarios and model recommendations 1. Urban and rural ring network power supply -Scenario requirements: Dual radiation line switching, cable branch control.   -Recommended model: FLN36-12D (three station, with grounding knife).   2. Box type substation -Scenario requirements: Compact design, high protection level (IP67).   -Recommended model: FZN25-12 (SF6 insulation, wide temperature range -30 ℃~+40 ℃).   3. New energy access -Scenario requirement: frequent switching (photovoltaic inverter protection).   -Recommended model: VSC12 (vacuum arc extinguishing, operating life 30000 times).  

4、 Operation and maintenance optimization strategy 1. Mechanical characteristic monitoring -Check the opening and closing time every 2000 operations (standard: opening ≤ 45ms, closing ≤ 80ms).   2. Contact wear management -Replace the silver tungsten alloy contact when the thickness is less than 3mm (detected by a laser thickness gauge).   3. Intelligent upgrade -Add edge computing module to realize local fault diagnosis (such as arc light protection prediction).