Core Structure and Working Principle
1. Core Components
Step-up Transformer: The core of the photovoltaic (PV) transformer, typically using a Dyn11 connection group. It steps up the low-voltage side (usually 0.4kV) AC power to 10kV/35kV, featuring low loss and strong short-circuit withstand capability, suitable for the large diurnal load fluctuations of PV power plants.
Low-voltage compartment: Contains low-voltage circuit breakers, disconnect switches, inverter grid connection switches, energy metering devices, surge protectors, reactive power compensation capacitors (SVG/SVC), etc., responsible for the collection, protection, and power factor regulation of low-voltage side power.
High-voltage compartment: Contains high-voltage load switches, fuses, surge arresters, voltage transformers (PTs), current transformers (CTs), etc. Some high-voltage models include vacuum circuit breakers, responsible for high-voltage side grid connection control, short-circuit protection, and energy metering.
Measurement and Control Protection System: Integrates a dedicated photovoltaic measurement and control terminal, capable of monitoring data such as voltage, current, power, and power generation. It features overvoltage, undervoltage, overcurrent, lightning protection, and anti-islanding protection functions, and supports remote communication (RS485 / Ethernet) for access to the power station monitoring platform.
Enclosure Structure: Constructed of corrosion-resistant steel plate or stainless steel, with a protection rating ≥ IP54. It provides sun protection, rain protection, dust protection, and condensation prevention. Some enclosures are equipped with forced air cooling or temperature-controlled heat dissipation devices, suitable for outdoor high-temperature, high-humidity, and windy/sand-dust-prone environments.
2. Working Principle
Photovoltaic modules generate electricity → Inverter converts DC power to 0.4kV AC power → Collected in the combiner box and connected to the low-voltage room of the photovoltaic transformer → Sent to the step-up transformer via low-voltage switch and protection device → Stepped up to 10kV/35kV → Passed through the switchgear and protection device in the high-voltage room → Connected to the public power grid or power station collection line.
