surge protector

 A Comprehensive Analysis of CHINT Surge Protectors

As a leading global manufacturer of electrical equipment, CHINT's surge protector product line covers various scenarios such as alternating current (AC), direct current (DC), and signals, providing a full range of solutions from basic protection to high-energy protection. The following explanations are presented from aspects including core technologies, product classifications, selection guidelines, application scenarios, and installation and maintenance:

I. Core Technologies and Working Principles

Surge Protective Devices (SPDs) achieve overvoltage suppression through non-linear components such as Metal Oxide Varistors (MOVs) and Gas Discharge Tubes (GDTs). When there is an instantaneous high voltage in the circuit (such as lightning strikes or power grid fluctuations), the SPD quickly conducts, releasing the surge energy to the ground and protecting the rear-end equipment.

- **Core Components**:

  - **MOV**: A ceramic-based component whose resistance drops sharply when the voltage increases, conducting the current.

  - **GDT**: A gas discharge tube with a fast response speed (in the nanosecond range), suitable for high-energy surges.

  - **Backup Protection**: Fuses or circuit breakers to prevent short circuits caused by SPD failures.

II. Product Classifications and Typical Models

1. Power Surge Protectors (AC/DC)

- **NA Series (AC Type)**

  - **Application Scenarios**: AC 220V/380V power grids, distribution boxes, and building power distribution systems.

  - **Model Examples**:

    - **NA-40KA/385V**: Nominal discharge current of 40kA, voltage protection level ≤ 1.8kV, and supports thermal tripping protection.

    - **NA-60KA/420V**: Maximum discharge current of 60kA, suitable for industrial-grade environments with high surge risks.

- **NDU Series (DC Type)**

  - **Application Scenarios**: DC 12V/24V/48V/1000V systems (such as photovoltaic systems and communication base stations).

  - **Model Examples**:

    - **NDU-20KA/1000V**: DC arc extinguishing technology, response time ≤ 25ns, suitable for the DC side of photovoltaic inverters.

    - **NDU-40KA/500V**: Supports a maximum continuous operating voltage of 500V DC, used in energy storage battery systems.

- **U4 Series (Internationally Certified Type)**

  - **Application Scenarios**: Systems below AC 600V, in compliance with UL 1449 and IEC 61643-11 standards.

  - **Model Examples**:

    - **U4-40KA/480V**: Modular design, supports DIN rail installation, suitable for the North American market.

 2. Signal Surge Protectors

- **NDS Series**

  - **Application Scenarios**: Interfaces such as RJ45, BNC, and RS485, protecting signal lines of networks, monitoring systems, and sensors.

  - **Model Examples**:

    - **NDS-ETH**: Lightning protection for 10/100/1000M Ethernet, response time ≤ 1ns, insertion loss ≤ 0.5dB.

    - **NDS-VIDEO**: Coaxial video signal protection, supporting 1080P high-definition transmission.

3. Surge Protectors Dedicated for New Energy

- **NXU Series (Photovoltaic/Charging Pile)**

  - **Application Scenarios**: Photovoltaic combiner boxes, power supplies, and communication interfaces of charging piles.

  - **Model Examples**:

    - **NXU40KA/350V DC**: DC side protection for photovoltaic systems, supports 1000V DC systems, and has passed the TUV certification.

    - **NXU-COM**: Lightning protection for 4G/Ethernet interfaces of charging piles, protection level IP65.

III. Key Parameters and Guidelines for Selection

1. **Rated Voltage (Un)**

   - It needs to match the operating voltage of the circuit (such as AC 220V, DC 12V). For DC systems, a DC-type SPD must be selected.

2. **Maximum Continuous Operating Voltage (UC)**

   - Slightly higher than the normal voltage of the circuit (for example, a UC of 250V is suitable for a 220V power grid) to avoid aging caused by long-term overvoltage.

3. **Nominal Discharge Current (In)**

   - For home scenarios, select 10-20kA, and for industrial scenarios, more than 20-40kA is required. For example:

     - **NA-40KA**: Suitable for residential distribution boxes.

     - **NA-60KA**: Suitable for the main incoming line of factories.

4. **Voltage Protection Level (Up)**

   - The smaller, the better (for example, ≤ 1.5kV is safer for precision equipment), and it needs to be lower than 80% of the equipment's impulse withstand voltage (Uw).

5. **Response Time (Tr)**

   - For high-frequency signal protection, it needs to be ≤ 1ns (such as NDS-ETH), and for power protection, ≤ 25ns.

6. **Installation Method**

   - Parallel type (for power supplies) and series type (for signals), which need to be selected according to the circuit topology.

IV. Typical Application Scenarios

1. Home and Office

- **Requirements**: Protect household appliances such as TVs, computers, and routers from lightning strikes or power grid fluctuations.

- **Solutions**:

  - **NA-20KA/275V**: Single-phase socket-level protection, with a price of about 21-34 yuan.

  - **NA-40KA/385V**: Main protection for distribution boxes, with a price of about 65-78 yuan.

2. Industrial and Power Systems

- **Requirements**: Protect motors, frequency converters, and PLC controllers, and deal with power grid harmonics and surges caused by switch operations.

- **Solutions**:

  - **NA-60KA/420V**: Factory main distribution cabinets, with a price of about 100-120 yuan.

  - **NDU-40KA/500V DC**: DC side of photovoltaic inverters, with a price of about 55-88 yuan.

3. New Energy Field

- **Photovoltaic Systems**:

  - **NDU-20KA/1000V DC**: DC protection for combiner boxes, with a price of about 38-55 yuan.

  - **NA-40KA/385V**: AC side protection for inverters, with a price of about 65 yuan.

- **Charging Piles**:

  - **NXU40KA/350V DC**: Protection for DC fast charging guns, with a price of about 55 yuan.

  - **NDS-COM**: Lightning protection for communication interfaces, with a price of about 23-35 yuan.

4. Data Centers and Communications

- **Requirements**: Protect servers and switches from transient overvoltages during signal transmission.

- **Solutions**:

  - **NDS-ETH**: Network interface protection, with a price of about 34-48 yuan.

  - **NA-40KA/385V**: Protection for the input side of UPS, with a price of about 65 yuan.

V. Installation and Maintenance Suggestions

1. **Grounding Requirements**

   - The grounding wire needs to be shorter than 0.5 meters, and the grounding resistance ≤ 4Ω to avoid protection failure due to poor grounding.

2. **Multi-stage Coordination**

   - Main incoming line (primary protection, such as NA-60KA) → Distribution box (secondary protection, such as NA-40KA) → Equipment end (tertiary protection, such as NA-20KA), gradually reducing the surge energy level by level.

3. **Regular Inspection**

   - Check the status through the SPD indicator light or professional tools, and replace it in a timely manner after it fails.

4. **Environmental Adaptability**

   - For outdoor installation, select a protection level of IP65 (such as the NXU series), and derate the use in high-temperature environments.

VI. Price References and Purchase Channels

- **Purchase Channels**: 

  - **International**: Query local agents through the CHINT global official website .

 VII. Advantages Compared with Competitors

1. **Full Scenario Coverage**: From home use to industrial and new energy applications, CHINT provides a full range of SPDs for AC/DC/signals, adapting to different voltage levels (from 12V to 1000V).

2. **High Cost-effectiveness**: The price of products with the same specifications is about 30% lower than that of international brands (such as ABB and Schneider), and customized solutions are supported.

3. **Complete Certifications**: Passed certifications such as UL, CE, and CQC, and complies with standards such as IEC 61643-11 and GB/T 18802.1.

4. **Localized Services**: Provide 7×24-hour technical support in China, and overseas, quick responses are provided through agents.

 VIII. Summary

With its rich product line, high reliability, and cost-effectiveness, CHINT surge protectors have become the mainstream choice in fields such as home, industry, and new energy. When selecting, it is necessary to comprehensively evaluate according to the voltage type, surge risk level, and importance of the equipment, and give priority to considering the current-carrying capacity, residual voltage level, and adaptability. For example:

- **Home Users**: Select NA-20KA/275V (socket level) + NA-40KA/385V (distribution box level).

- **Photovoltaic Systems**: NDU-20KA/1000V DC (DC side) + NA-40KA/385V (AC side).

- **Charging Piles**: NXU40KA/350V DC (power supply) + NDS-COM (communication).

Through reasonable selection and installation, CHINT surge protectors can effectively protect equipment from surge damage and improve system stability.