50MW Utility-Scale Solar Farm Grid Connection System
Complete balance-of-system electrical package for a utility-scale solar farm in Northwest China. From PV string combiner boxes through MV switchgear to grid-tie step-up transformer — a fully integrated, CQC-certified solution engineered for extreme desert environments.
Delivering a Complete Grid-Tie Electrical Package for Utility-Scale Solar
This 50MW DC / 40MW AC utility-scale solar farm is located in the Gobi Desert region of Northwest China — an area with exceptional solar irradiance but harsh environmental conditions including extreme temperatures, high winds, and frequent dust storms.
GOHO was selected as the primary electrical equipment supplier, responsible for the complete balance-of-system (BOS) electrical package from the PV array string level all the way to the medium-voltage grid connection point. Our scope included design, manufacturing, testing, and on-site commissioning support.
The project required equipment capable of withstanding ambient temperatures ranging from -30°C to +50°C, high UV exposure, and dust ingress — all while maintaining grid code compliance for harmonic distortion and power factor.
- Complete BOS electrical package from string combiner to MV grid-tie
- CQC-certified PVSZ series PV combiner boxes with IP65 protection
- KYN28-12 medium-voltage switchgear with solar-specific protection relays
- 3150kVA step-up power transformer with ONAN cooling
- Full SCADA integration for remote monitoring and unmanned operation
- Successfully commissioned and connected to the provincial grid in 2023
📋 Project at a Glance
(Gobi Desert Region)
MV Switchgear
Step-up Transformer
Three Key Challenges We Solved
Utility-scale solar farms in desert environments present unique engineering challenges. Here’s how our team addressed the critical requirements.
Extreme Environmental Conditions
The Gobi Desert site experiences temperatures from -30°C in winter to +50°C in summer, combined with high UV radiation, strong winds, and frequent dust storms. Standard electrical enclosures would fail rapidly under these conditions, requiring equipment with enhanced environmental protection, anti-corrosion coatings, and wide-temperature-range components.
Strict Grid Code Compliance
The provincial grid operator imposed stringent requirements for harmonic distortion (THD < 3%), power factor (≥ 0.98), and low-voltage ride-through (LVRT) capability. Meeting these standards required careful system design, harmonic filtering, and protection relay coordination across the entire MV-LV chain from inverter to grid connection point.
Remote Unmanned Operation
Located in a remote desert region 200km from the nearest city, the solar farm must operate with minimal on-site personnel. The system required comprehensive SCADA integration, string-level monitoring, remote fault diagnosis, and automated alerting to ensure maximum uptime and efficient maintenance response.
Integrated Solar Farm Electrical Solution
A complete, end-to-end electrical package engineered specifically for utility-scale solar farms operating in harsh environments.
CQC-Certified Outdoor PV Combiner Boxes
Our PVSZ series PV string combiner boxes are purpose-built for outdoor solar farm deployment. CQC certified and tested to withstand the harshest environmental conditions.
- IP65 weatherproof enclosure rating
- Anti-corrosion coating for desert dust
- Wide operating temperature: -40°C to +70°C
- UV-stabilized polycarbonate terminal covers
- Stainless steel mounting hardware
PVSZ Solar Combiner with String Monitoring
Each PVSZ combiner box integrates string-level current monitoring and surge protection, enabling precise performance tracking and rapid fault localization.
- 16/24 string inputs with DC fuse protection
- Per-string current monitoring via RS485
- Type II DC surge protection devices
- DC disconnect switch with load-break capability
- Smart monitoring module with Modbus RTU
Grid-Tie Package: Transformer + Switchgear + Protection
The MV grid-tie substation package combines a 3150kVA step-up transformer with KYN28-12 metal-clad switchgear and comprehensive protection relays for reliable grid connection.
- 3150kVA 10.5kV/0.69kV step-up transformer (ONAN)
- KYN28-12 MV switchgear with VCB breakers
- Solar-specific protection relays (50/51, 67, 81, 59N)
- Anti-islanding protection (59/81, rate of change)
- SCADA integration with Modbus TCP/IP
Equipment Delivered to the Project
Four key product categories formed the complete electrical balance-of-system package for this 50MW solar farm.
PVSZ PV String Combiner Boxes
16-input and 24-input DC combiner boxes with string monitoring, surge protection, and IP65 outdoor-rated enclosures. CQC certified for PV applications.
BWG PV Grid-Connected Cabinet
AC-side grid-connected distribution cabinet with metering, surge protection, and circuit breaker protection for string inverter outputs. Type-tested assembly.
KYN28-12 MV Switchgear
Metal-clad withdrawable switchgear with vacuum circuit breakers, solar protection relays, and PT/CT panels. 12kV rated, 630A–1250A current range.
3150kVA Step-up Power Transformer
Oil-immersed step-up transformer, 3150kVA, 0.69kV/10.5kV, ONAN cooling, with off-circuit tap changer and comprehensive protection accessories.
Performance After 2 Years of Operation
The solar farm has been operational since Q2 2023, delivering exceptional performance and reliability across all measured metrics.
(System Uptime)
(Grid Code Compliant)
(Low System Losses)
(in 2 years of operation)
Inside the Manufacturing & Assembly Process
A look at our production facility where all solar farm electrical equipment is designed, manufactured, and tested before shipment.
Solar Equipment Certifications
All PV combiner boxes and grid-connection equipment supplied to this solar farm is CQC-certified and grid-code compliant, with complete type test documentation from accredited testing laboratories.
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