Introduction: Seizing the Momentum – Focusing on the Rise of Photovoltaics

In recent years, the photovoltaic (PV) and wind power sectors have gained unprecedented popularity as core clean energy sources. This rise has been driven by heightened global environmental awareness and supportive policies promoting energy conservation and emission reduction. Rapid technological advancements have significantly reduced the cost of renewable energy generation, serving as a key catalyst for the industry’s explosive growth.
Data shows that from 1997 to 2016:

• Global wind power installed capacity grew 66-fold (from 7.64GW to 467GW),
• Photovoltaic capacity expanded over 1,200-fold (from 0.23GW to 301GW).

This indicates that PV and wind energy are leading a major transformation in the global energy landscape. Against this backdrop, Shanghai Liangxin Electrical Co., Ltd. ("Nader Electrical"), a professional low-voltage electrical component manufacturer, has keenly captured the industry's pulse. By investing heavily in R&D, Nader has successfully developed a range of dedicated products—most notably high-voltage DC molded case circuit breakers—effectively supporting the industry's demand for reliable low-voltage electrical components.

Part I: Nader Electrical’s Full-Scope PV System Solutions

Nader provides complete and tailored low-voltage electrical solutions for various PV system types, including centralized, string, and distributed systems. We firmly believe that "the best solution is the most suitable one." With targeted product combinations, we address the needs for performance, safety, and cost control in photovoltaic systems.

1. Centralized PV System Solutions

From combiner boxes to inverters and step-up transformers, Nader has a complete layout of low-voltage products:

► Combiner Boxes:

• DC1100V Systems: Recommended product – NDM3Z Series DC molded case circuit breakers.
• DC1200V / DC1500V Systems: Recommended products – NDM3Z-250V and NDM5Z Series DC molded case circuit breakers.
  • Performance: NDM5Z supports up to 250A and 40kA breaking capacity at DC1000V/DC1200V.
  • Industry Adoption: Selected by CGN and other leading enterprises.
  • Technology Breakthrough: As DC1500V represents the upper limit for low-voltage devices, Nader formed a dedicated team, using advanced simulation tools to overcome multiple technical challenges. These products are now the preferred protective components for DC1500V high-voltage combiner boxes.

► Inverters:

• AC Contactors:
  • NDC1 Series electromagnetic contactors support up to AC1000V and 2650A under AC-1 conditions.
  • NDC5K Series vacuum contactors are independently developed and boast an electrical life of up to 1 million cycles.
• High-Current MCCBs:
• NDM3EX-1600 Series AC molded case breakers fill the domestic gap above 1000A, with a 30% smaller footprint—ideal for compact inverter cabinets. These 1600A models are now widely used in PV power stations.

► Prefabricated Substations:

• NDW3 Series Frame Circuit Breakers:
  • Designed for renewable energy systems like PV and wind.
  • Voltage Suitability: Rated up to AC1000V; supports systems of AC690V and AC1000V.
  • Breaking Capacity: Up to 55kA, ideal for high-power systems (1.25MW, 2.5MW, 3.125MW).

2. String PV System Solutions

► DC Side (Inverters):

• NDG3V Series DC isolator switches:
  • Specially designed for PV applications;
  • Support DC1100V/DC1500V via dual-layer series wiring;
  • Handle 20A–50A with load break capability at industry-leading performance.

► AC Combiner Boxes:

• NDM3 Series MCCBs:
  • 400A units rated at 500VAC with 50kA breaking capacity and current limiting for cascade protection.
• NDM3A Series:
• Tailored for 800VAC systems with enhanced breaking capabilities.
• Advanced dual-breakpoint contacts;
• 400A breakers can handle 85kA at 500VAC—the smallest size in their class.
• NDM5 Series:

3. Distributed PV Systems (Residential & Village-Level)

► Residential Distributed PV:

• DC Side: NDG3 Series isolators.
• Grid Connection Side: NDB2 Series miniature circuit breakers:
  • Enable quick disconnection in case of AC short circuits;
  • Optional voltage detection module for over/under-voltage protection and auto reclosing.

► Village-Level PV:

• Inverters: Also use NDG3V Series isolators.
• Combiner Boxes: NDM3 Series molded case breakers:
  • Rated 500V/400A with 50kA breaking capacity;
  • Support optional voltage detection module for enhanced reliability.

Application Proven: These solutions have been deployed in over 30GW of PV stations globally, with stable performance and reliable operation.

Part II: Addressing Core Pain Points in Low-Voltage PV Applications

Nader has systematically identified the key challenges facing low-voltage devices in PV applications and offers targeted solutions.

Summary of Core Pain Points

1. Poor Environmental Adaptability: Failures caused by extreme cold, high altitude, humidity, salt spray, and electromagnetic interference.
2. DC Arc Risk: Difficult arc extinction during disconnection under high-voltage DC, leading to equipment damage and fire hazards.
3. Other Common Failures: High temperature rise, poor accessory reliability, contact welding, coil burnout.

Nader’s Response Strategies

► Challenge 1: Achieving Outstanding Environmental Adaptability

Low-Temperature Resistance:

• Use special plastics rated for -40°C;
• Employ specialized lubricants that remain fluid at -50°C;
• All designs pass -40°C testing with certifiable reports.

High Altitude De-rating Prevention:

• Optimize busbar and contact structure to reduce heat loss;
• Use MDC-5 high-insulation materials to maintain dielectric strength;
• Improve arc chamber material for faster deionization, enhancing breaking capacity by 23%.

Salt Spray Resistance (for Offshore PV):

• PCB protected with conformal coating;
• Connectors plated with gold/nickel for corrosion resistance;
• Housing parts treated with trivalent chromate zinc plating;
• Use brass parts for wear-prone areas to prevent layer degradation;
• Motors use anti-corrosion lubricants with added rust-removal properties;
• All improvements verified by certified tests for moisture, mold, and salt spray resistance.

► Challenge 2: Effectively Solving DC Arc Extinction

Background:

• DC has no zero-crossing point, making disconnection highly challenging;
• Failed arc extinction can rapidly lead to fires;
• Fires in rooftop PV systems pose serious safety risks and are hard to extinguish.

Nader’s Multi-Layered Arc Suppression Technology:

• Side arc-transfer design using silver contacts to rapidly guide the arc to the arc chamber;
• U-shaped contact structure for faster arc separation;
• 14 arc chute plates enhance magnetic blowout capability;
• Increased contact gap and VJC gas-generating technology for better extinction;
• Shaft seal design prevents ion intrusion, enabling reliable use on bottom-fed applications.

Proven Use Cases:

• China: Suqian Tianganghu 200MW "PV+Fishery" project, Yangquan 100MW PV Leader project;
• Overseas: 900MW PV project in Pakistan, 500MW in India (Rudrapur & Hyderabad).

Part III: Building Trust with Strength – The Foundation of Nader's Growth

Nader has maintained an impressive 30% compound annual growth rate for over a decade—an exceptional feat in the traditional low-voltage electrical industry. This success stems from a clear strategy, robust systems, and unwavering customer commitment.

Strategic Positioning:

• Goal: Become the “Expert in High-End Low-Voltage System Solutions”;
• 16 segmented industries decoded, with tailored product development driven by actual usage environments and working conditions.

R&D System (IPD Framework):

• Covers full product lifecycle—from strategy, planning, and development to launch and end-of-life;
• Significantly enhances R&D efficiency.

Certified Laboratory:

• Nearly RMB 200 million invested;
• Certified by CNAS (China), UL (USA), and TUV (Germany);
• Supports 35 major and 200+ sub-categories of tests;
• AC test capacity up to 200kA—unmatched among Chinese brands.

Manufacturing System:

• 26 automated production lines;
• SMES system for real-time data monitoring and control;
• Industry 4.0-ready automated production line under installation.

Marketing & Service Network:

• 71 domestic offices, 4 overseas offices;
• 450+ sales professionals for timely, professional service;
• Only Chinese low-voltage brand offering a 3-year warranty.

Major Achievements (2017 as an example):

• Sales revenue of approx. RMB 1.7 billion;
• R&D Center named National Enterprise Technology Center;
• 537 patents filed, 26 new products launched;
• Strategic partnerships with 20 of China’s top 30 real estate developers;
• Recognitions: Emerson “Excellent Supplier”, Vanke “Class A Supplier”, Sungrow “Innovation Award”, Huawei “Best Supplier”;
• Product support for National PV Leader Projects, Suzhou Data Center, and Shidaowan Nuclear Power Station.