1. Main wiring of photovoltaic power station
High voltage main wiring
Voltage level: Select according to the system voltage requirements, usually using 10kV, 20kV or higher voltage.
Circuit breaker: Select outdoor high-voltage circuit breakers (SF6 or air respirators) with a rated current of the maximum current of the photovoltaic system.
Busbar: High precision outdoor busbars are selected to meet the impedance requirements of the system.
Example: High precision outdoor busbar, made of copper or aluminum, with a thickness of 0.5mm and a length of 10m.
2. Inverter
High Voltage Inverter
Power level: Choose an inverter that matches the total power of the photovoltaic system, and it is usually recommended that the inverter power be ≥ the power of the photovoltaic system.
Power factor: Ensure that the inverter power factor is ≥ 0.9 (recommended ≥ 0.95).
Control method: Adopting current source inverter, supporting reactive power compensation and power factor adjustment.
3. Low voltage AC grid connected cabinet
Outdoor high-voltage cabinet
Capacity: Choose an outdoor high-voltage cabinet with a total system power of ≥ 1MVA (1000kVA).
Example: Outdoor high-voltage cabinet with a capacity of 1000kVA and a voltage level of 10kV, equipped with busbars, circuit breakers, isolation switches, and surge protectors.
Functional modules: equipped with busbars, circuit breakers, isolation switches, surge protectors, etc., to meet grid connection requirements.
4. Voltage and current transformers
Voltage transformer
Type: High precision voltage transformer, usually selected as 600/600 type.
Parameters: Rated voltage 600V, accuracy level 0.5.
Example: 600/600 type voltage transformer, rated voltage 600V, accuracy level 0.5.
Current transformer
Type: High precision current transformer, usually selected as 500A/500A or 1000A/1000A type.
Parameters: Rated current of 1000A, accuracy level of 0.5.
Example: 1000A/1000A current transformer, rated current 1000A, accuracy level 0.5.
Selection principle
Power matching: When selecting equipment, the power level should be greater than or equal to the system requirements to avoid overload.
Stability: The stability of inverters and high-voltage cabinets directly affects the reliability of grid connected systems. It is recommended to choose well-known brand equipment.
Environmental adaptability: Outdoor equipment should have dust-proof, windproof, corrosion-resistant and other properties, suitable for outdoor environments.
Scalability: Device selection should consider future power upgrade requirements to ensure system flexibility.
Equipment parameters
High Voltage Inverter
Specification: 315kW, voltage 10kV, power factor 0.95, current source inverter.
High voltage main wiring
Circuit breaker: PX25-10kv-1000A (10kv, 1000A current).
Busbar: High precision outdoor busbar, made of copper or aluminum material, with a thickness of 0.5mm and a length of 10m.
Low voltage AC grid connected cabinet
Model: Outdoor high-voltage cabinet, capacity 1000kVA, voltage level 10kV, equipped with busbar, circuit breaker, isolation switch and surge protector.
Voltage transformer
Model: 600/600 voltage transformer, rated voltage 600V, accuracy level 0.5.
Current transformer
Model: 1000A/1000A current transformer, rated current 1000A, accuracy level 0.5.
Summary
Main wiring: Select outdoor high-voltage circuit breakers and high-precision busbars.
Inverter: Choose a current source inverter with power matching and high power factor.
Low voltage cabinet: outdoor high voltage cabinet, equipped with busbar, circuit breaker and other functions.
Transformer: Select high-precision and appropriately rated voltage and current transformers.