Project Overview
This project is a 10MW solar PV grid connection project designed to provide a safe, reliable, and efficient photovoltaic grid connection system for the distributed renewable energy generation project of China Electrical Equipment Group Co., Ltd. It adopts a 10kV solar PV grid connection solution integrating voltage transformation, power collection, protection, energy metering, and grid integration functions.
The project is also equipped with an energy storage system to establish an integrated “PV + Energy Storage” operation mode. By regulating power output through energy storage, the system improves the stability of renewable energy generation. It enhances grid compatibility, allowing it to better adapt to the operational requirements of the power grid.
As a standardized demonstration project for distributed clean energy grid integration, Wondon provides a one-stop solution covering electrical system design, core equipment supply, and system integration support. This comprehensive service ensures reliable grid-connected operation and long-term performance for renewable energy projects.
Overall System Architecture
This project adopts a layered system architecture featuring “voltage step-up→power collection → grid connection → regulation → monitoring”, enabling complete electrical integration and intelligent management from the photovoltaic generation side to the grid connection point.
The overall architecture is designed for efficient PV grid integration, enabling coordinated operation between photovoltaic generation, energy storage, and the utility grid.
1. PV Voltage Step-Up Process
The DC electricity generated by photovoltaic modules is converted into AC power through inverters and stepped up to 10kV through pad-mounted transformers, forming the core process of the photovoltaic grid connection system.
2. Medium-Voltage Power Collection Process
Multiple 10kV step-up circuits are connected to the No.1 and No.2 prefabricated 10kV switchgear stations. The medium-voltage switchgear completes power collection, feeder protection, and energy metering functions.
3. Grid Connection Process
After power collection, the electricity is connected to the public power grid through the dedicated 10kV outgoing feeder bay of the 35kV substation, ensuring a safe and reliable connection between the photovoltaic power station and the power system.
4. Energy Storage Regulation Process
The supporting energy storage system is connected to the 10kV busbar. Through intelligent charge and discharge control, it provides functions such as smoothing photovoltaic power output, peak-valley regulation, and emergency backup.
5. Intelligent Monitoring Process
The project is equipped with a computer monitoring and communication system to achieve real-time operating status monitoring, data acquisition, remote control, and power dispatch communication for key equipment, including pad-mounted transformers, switchgear stations, and the energy storage system.
Core Electrical Equipment Configuration
1. Pad-Mounted Transformer System
As a key component of the solar PV grid connection system, the pad-mounted transformer is responsible for voltage conversion and power collection from PV inverters.
This project adopts an outdoor integrated pad-mounted transformer (Chinese-style prefabricated substation) design, which integrates the transformer, medium-voltage switchgear, and low-voltage distribution equipment into an independent enclosure. With a compact structure, convenient installation, and strong environmental adaptability, this design is suitable for distributed photovoltaic projects with multiple dispersed installation points.
(1) Transformer Configuration
The project uses an S11-1600kVA oil-immersed transformer, which provides high operational reliability and low energy consumption.
The main transformer specifications are as follows:
- Rated capacity: 1600kVA
- Cooling method: ONAN
- No-load loss: 1550W
- Load loss: 18200W
This transformer meets the requirements for long-term continuous operation of photovoltaic power plants. It effectively reduces operating losses and improves the overall economic efficiency of the system.
(2) Medium-Voltage Compartment Configuration
The medium-voltage compartment of the pad-mounted transformer uses an XGN15-12 ring main unit (RMU), with the following main components:
- VS1-12/630A fixed vacuum circuit breaker
- GN30-12 isolating switch
The medium-voltage side provides reliable switching control, feeder protection, and safe isolation functions, ensuring stable operation of the photovoltaic step-up circuits.
(3) Low-Voltage Compartment Configuration
The low-voltage compartment adopts a GGD-type low-voltage distribution cabinet, mainly equipped with:
- Air circuit breakers and molded case circuit breakers
- Type T1/T2 surge protective devices (SPD)
- 2kVA UPS uninterruptible power supply
- Temperature and humidity controller
With comprehensive low-voltage protection and auxiliary power supply design, the system ensures safe and stable operation of internal pad-mounted transformer equipment.
(4) Structural Design and Additional Configurations
The enclosure adopts a 1.5mm cold-rolled steel plate structure, providing excellent mechanical strength and outdoor protection performance.
The internal conductors use high-conductivity copper busbars to meet the requirements for current-carrying capacity and operational reliability during long-term operation. The design is also well suited for the continuous outdoor operating conditions of photovoltaic projects.
2. 10kV Containerized Substation
To meet the requirements of rapid construction, efficient grid connection, and modular deployment for distributed photovoltaic projects, the No.1 and No.2 switchgear stations in this project adopt a factory-built 10kV prefabricated containerized substation solution.
Compared with traditional civil-engineered substations, our containerized substation solution integrates medium-voltage switchgear, secondary protection systems, auxiliary control systems, and environmental control systems into standardized enclosures. This design enables factory pre-assembly, complete transportation, and fast on-site installation, effectively shortening the construction period and reducing the complexity of on-site installation.
This prefabricated solution is widely applied in large-scale distributed photovoltaic projects requiring fast deployment and reliable grid connection.
(1) Container Structure Design
The dimensions of each container are:
Length 8.55m × Depth 3.3m × Height 3.2m
The container adopts an outdoor enclosed steel structure design, with medium-voltage equipment installation, secondary wiring, and system commissioning completed in advance at the factory.
During on-site installation, workers only need to complete foundation construction, equipment positioning, and external cable connections before the system can be put into operation. This significantly reduces civil construction and installation workload, helping accelerate overall project implementation.
(2) Electrical Function Configuration
The prefabricated container integrates complete 10kV medium-voltage power distribution functional units, including:
- Grid connection outgoing feeder cabinet
- PT cabinet
- Integrated protection cabinet
- Energy metering equipment
- Related secondary control and communication equipment
The complete system provides key functions including:
- 10kV photovoltaic power collection
- Line protection and fault isolation
- Energy metering and data acquisition
- Operation status monitoring and control
These functions enable the system to meet the grid connection and operation requirements of distributed photovoltaic power plants.
(3) Auxiliary System Configuration
To ensure long-term stable operation of the equipment, the prefabricated container is equipped with comprehensive environmental control, safety protection, and operation & maintenance auxiliary systems.
① Environmental Control System
Configuration:
- Internal lighting system
- HVAC system
- Temperature and humidity control devices
By regulating the internal operating environment, the system ensures the long-term stable operation of medium-voltage equipment and secondary devices.
② Safety Protection System
Configuration:
- Smoke detectors
- Fire alarm control panel
- Fire extinguishers
- Audible and visual alarm devices
- Safety warning signs
- Electromagnetic interlocking devices for cabinet doors
Through multiple safety protection measures, the system enhances the overall equipment operation safety level.
③ Operation & Maintenance Auxiliary System
Configuration:
- Maintenance power sockets
- Emergency lighting system
These facilities support routine inspections, equipment maintenance, and troubleshooting operations.
(4) 10kV Medium-Voltage Switchgear (KYN28-12)
The core primary equipment inside the prefabricated container adopts the technically mature KYN28-12 armored withdrawable medium-voltage switchgear, featuring reliable structure, high safety performance, and convenient maintenance.
The main configurations include:
① Cabinet type
KYN28-12 indoor medium-voltage switchgear, supporting withdrawable circuit breaker maintenance and providing enhanced safety during inspection and servicing.
② Core components
Equipped with VS1-12 withdrawable vacuum circuit breakers, supporting rated currents of 630A/1250A and short-circuit breaking capacities of 25kA/31.5kA. The design can meet the requirements of different circuits, including incoming feeders, outgoing feeders, and PT circuits.
③ Integrated components
The switchgear integrates a complete set of components, including current transformers, zero-sequence current transformers, voltage transformers, surge arresters, earthing switches, primary resonance suppression devices, and intelligent control units. This configuration meets comprehensive requirements for protection, measurement and control, and safety interlocking.
Energy Storage Power Station Supporting Design
The integrated PV Energy Storage System enhances renewable energy utilization and improves the flexibility of the solar PV grid connection project. By actively regulating power output, the energy storage system improves the operational flexibility of the photovoltaic project and reduces the impact of renewable energy fluctuations on the power grid.
System Integration Scheme
The energy storage system adopts a 10kV voltage-level connection scheme and is directly connected to the 10kV busbar of the switchgear station, enabling coordinated operation with the photovoltaic power generation system.
Main System Components
- Standardized battery container
- PCS energy storage converter
- 160kVA 10/0.4kV station service transformer
- BMS battery management system
Core Value
- Smooth photovoltaic power output fluctuations and improve the stability of renewable energy generation;
- Participate in peak-valley electricity price regulation and improve energy utilization efficiency;
- Provide auxiliary peak regulation services for the power grid and enhance system regulation capabilities;
- Provide emergency backup power, improve power supply reliability, and reduce the impact of grid connection fluctuations on the power system.
Monitoring and Communication System
The project is equipped with a complete automated monitoring and communication system to meet the requirements for information-based and automated operation of distributed photovoltaic grid-connected systems.
1. Computer Monitoring System
The computer monitoring system enables:
- Data acquisition of operating parameters such as voltage, current, and power
- Monitoring of switchgear operating status
- Fault alarm information management
- Remote operation and system control
2. Hierarchical Communication Topology
The project adopts a hierarchical communication structure. Through communication management units and industrial switches, the system integrates data exchange between protection devices, measurement and control devices, and the energy storage BMS system. It also supports standardized connection with the power grid dispatching platform.
3. Equipment Coordination Method
The secondary protection equipment and key communication management devices are selected and procured by the project owner according to grid connection requirements. Wondon is responsible for equipment installation inside the cabinets, system wiring, and engineering coordination to ensure coordinated operation of the overall system.
Project Highlights
1. Fast Delivery Through Prefabrication
The switchgear station adopts a factory pre-assembly model, with internal equipment wiring and commissioning completed at the factory. This significantly reduces the on-site construction period and meets the requirements for rapid grid connection of distributed energy projects.
2. Mature and Reliable Equipment Selection
All core electrical equipment adopts widely used and proven models and brands in the industry. The KYN28 switchgear has a high market presence, with well-established spare parts supply and maintenance systems, ensuring both long-term operational reliability and cost efficiency.
3. Integrated PV and Energy Storage Design
The photovoltaic and energy storage systems are planned simultaneously and connected through a unified integration scheme. This improves power quality and renewable energy utilization capacity while meeting the operational requirements of distributed power sources in modern power systems.
4. Comprehensive Safety Protection
The project is equipped with complete relay protection functions, including overcurrent, overvoltage, grounding, and zero-sequence protection. Combined with container fire protection, electrical interlocking, and environmental control systems, the design provides comprehensive protection for both equipment safety and grid operation reliability.
Service and Warranty Assurance
1. Full-Process Service Coverage
Wondon provides comprehensive services throughout the entire project lifecycle, including equipment manufacturing, factory testing, logistics transportation, on-site installation guidance, and grid connection acceptance support. We also provide continuous technical assistance to ensure smooth project implementation.
2. Quality and Warranty Commitment
(1) Before delivery, all equipment undergoes complete factory testing in strict accordance with the standards required by the project’s country or relevant industry regulations. This ensures that all performance parameters meet the specified requirements.
(2) We provide a 48-hour response service during the warranty period, along with long-term after-sales technical consultation support. Upon delivery, we provide complete technical documentation, including equipment certificates, factory test reports, operation manuals, packing lists, and other related documents.
Project Summary
From project requirement analysis and electrical system design to raw material procurement, equipment manufacturing, testing, and final delivery, Wondon completed the entire 10MW solar PV grid connection project within only 6 weeks.
Wondon provided a complete photovoltaic grid connection solution, including system design, customized electrical equipment manufacturing, project coordination, and delivery support. By optimizing every stage of the project process and ensuring strict quality control, Wondon successfully delivered reliable photovoltaic grid connection equipment and supporting energy storage solutions within the required schedule.
The delivered equipment received positive feedback from the project owner for its reliable performance, professional engineering services, and efficient project execution. This successful project demonstrates Wondon’s capability to provide fast-response, high-quality electrical solutions for renewable energy and distributed power projects.
FAQs
1. What is a Solar PV Grid Connection Project?
A solar PV grid connection project connects photovoltaic power generation systems with the utility grid through electrical equipment such as transformers, switchgear, protection devices, and monitoring systems. It ensures safe power transmission, grid compatibility, and stable renewable energy operation.
2. What equipment does a photovoltaic grid connection system include?
A complete photovoltaic grid connection system usually includes pad-mounted transformers, medium-voltage switchgear, prefabricated container substations, protection and metering devices, communication systems, and energy storage equipment. These components work together to achieve voltage conversion, power collection, and grid integration.
3. Why does a solar PV project need an energy storage system?
An energy storage system helps balance fluctuations in photovoltaic power output by controlling charging and discharging. It improves renewable energy stability, supports peak-valley regulation, enhances grid flexibility, and increases the overall utilization efficiency of solar power.
4. How long does it take to complete a Solar PV Grid Connection Project?
The project timeline depends on system scale, equipment requirements, and installation conditions. For this 10MW solar PV grid connection project, Wondon completed the full process from requirement analysis, electrical design, manufacturing, testing, and delivery within 6 weeks.
5. What services does Wondon provide for photovoltaic grid connection projects?
Wondon provides one-stop services for photovoltaic grid connection projects, including electrical system design, customized equipment manufacturing, factory testing, logistics support, installation guidance, and technical assistance. We help customers develop reliable grid connection solutions for renewable energy projects.
If you are looking for a reliable electrical equipment partner for photovoltaic projects, energy storage systems, or customized grid connection solutions, Wondon can provide professional engineering support and one-stop project services from design to delivery. Contact us to discuss your project requirements and develop a suitable electrical solution.