AFDD-63 Arc Fault Circuit Interrupters (AFCI, also known as AFDD Arc Fault Detectors) technology is a new circuit protection product. Its primary function is to detect and differentiate dangerous ground arc faults, parallel arc faults, and series arc faults, and promptly activate devices to interrupt the current to prevent electrical fires. In the event of an arc fault, due to the lower current strength, which is below the set values of overcurrent protection widely installed in the power system, especially in the low-voltage distribution field, installing an AFCI arc fault circuit interrupter at the distribution line terminal can promptly detect the arc and cut off the circuit, effectively reducing the losses caused by the arc.

The AFDD Fault Arc Circuit Breaker is an intelligent circuit protector featuring an integrated MCB and RCCB design. It can detect and identify fault arcs and normal arcs in the circuit. It prevents fire hazards caused by faulty arcs such as poor contact and insulation in electrical lines. It combines fault arc protection, overload protection, short-circuit protection, overvoltage protection, surge suppression, and leakage protection into one unit.

Field and Application

AFCI fault arc circuit breakers and AFDD fault arc detectors are primarily installed in distribution boxes of terminal power distribution systems, but can also be mounted in various control points such as homes, offices, large supermarkets, department stores, airports, textile factories, warehouses, oil depots, refineries, hotels, and oil transport pipelines. These devices can be installed anywhere electricity is used, and are widely used for electrical fire prevention.

Product Features

The AFDD Fault Arc Detector utilizes embedded system digital circuit control and an innovative arc feature recognition algorithm. It is compact yet powerful, enabling automatic monitoring and protection of fault arcs, effectively ensuring the safety of low-voltage distribution lines, electrical equipment, and personal safety.

A comprehensive arc fault detection method using a combination of time-domain typical feature detection of line current and frequency-domain FFT, achieving simultaneous localization in both time and frequency domains.

◆The specific features and functions are as follows:

(1) Features automatic and manual control functions;

(2) Features the ability to detect and differentiate dangerous ground fault arcs, parallel arc faults, and series arc faults.

(3) Features a mechanism that promptly and effectively drives the disconnection of the current to prevent electrical fires.

(4) Equipped with functions for detecting overcurrent, short circuit, overvoltage, etc.

(5) Features fault memory function for easy fault inquiry and analysis.

(6) Features an indicator light alarm

(7) Functionality with multiple rated currents and voltages

(8) Single-pole rated make and break function

(9) Function to display fault results

(10) Free-Release Feature

(11) Rust-proof, moisture-resistant, and electric shock protection

Compared to systems consisting of discrete component electronics, it features a self-matching control and protection characteristic.

The AFDD Fault Arc Detector integrates control and protection functions, equivalent to an Arc Detection Identifier + Circuit Breaker. It effectively resolves the matching issue between the protection and control characteristics of discrete components, making the collaboration between these features more rational.

Arc detection and protection features compared to circuit breakers and fuses

A conventional short-circuit protection mechanism based on circuit breakers and fuses can only meet equipment function protection in low capacity power grids. However, during arc faults due to the lower current strength, which is below the widely installed overcurrent protection setpoints in the current power system, especially in the low-voltage distribution field, it cannot provide protection against arc faults.

◆Compared to arc detection devices with sensors, it possesses detection characteristics.

Due to the necessity of installing the AFDD fault arc detector sensor at the location where the fault arc occurs when detecting arc parameters, this poses an inconvenience for detecting fault arcs in power supply lines. However, the AFDD effectively resolves this issue.

Compared to residual current devices (RCDs), offers real-time functionality.

During series and parallel arc faults, the fault impedance reduces the load current, causing it to fall below the RCD's trip value, thereby preventing the RCD from tripping promptly and in real time.

Product Advantages

● With built-in leakage protection, it enhances the reliability of electrical safety.
● Technically improved the electromagnetic mechanism, treated the materials, processes, and electronic circuits, thus avoiding the previous issues of overheating and high temperatures during prolonged operation of the electromagnet. This significantly reduced the working temperature of the electromagnet, extending its service life.
● Suitable for various types of loads, with high stability.
● The fault arc circuit breaker has a rated working current as high as 63A.
● Utilizes high-performance microcontrollers for system design, achieving digital control.
● Dedicated electromagnetic release mechanism, enhancing the accuracy of overcurrent protection.
When an arc fault occurs, the MCU internally makes multiple judgments, and only when all features match will the disconnection action be initiated.
● Wide application range for products, suitable for residents, enterprises, schools, and research institutions.
Integrated: Combines short-circuit protection, leakage protection, and arc protection into one
● Stability: Not affected by suppressive load or EMI load shielding on its detection capability
● Multi-domain detection: Time domain, Frequency domain
Flexible installation methods: plug-in, bolted, and track-mounted.

Main Structure

Subject: The AFCI Arc Fault Circuit Interrupter primarily consists of components such as the circuit breaker module, leakage module, power module, signal conditioning module, release mechanism module, and communication interface module.
◆ Power Module: Supplies power to the relevant components within the AFDD (Arc Fault Detection Device).
Signal Conditioning Module: The current signal from the main circuit is transmitted through a current transformer to the signal conditioning module. The module amplifies, rectifies, and filters the signal before sending it to the microcontroller for processing.
◆ Detent Module: The electromagnetic structure of the detent module in AFCI circuit breakers utilizes new energy-saving technology, reducing the core loss and short-circuit loss of the switching electromagnetic system, thereby conserving energy. A cushioning device has been added to minimize the energy impact on the electromagnetic system, enhancing the switch's latching performance and extending its service life. The operating mechanism of the detent module can receive fault signals detected by the main control chip MCU, cut off the coil circuit through controlled contacts, and interrupt the main circuit by the electromagnetic mechanism. After fault elimination, the operation button is pressed to reset.
Communication Interface Module: This module enables real-time transmission of data such as current, voltage, current phase, and arc signals to the terminal computer, allowing for remote monitoring. The image below shows the current data information sent by the MCU to the host computer during a series arc occurrence. The Data Processing Module utilizes a self-developed dedicated AFDD fault arc detector host computer development platform for data analysis and feature parameter extraction. A PC simulator is established to pre-simulate the algorithms on the PC, with the execution language being compatible with microprocessors.

Working Principle

The AFCI fault arc circuit breaker's main control chip MCU detects the current signal in the main circuit in real-time. Upon detecting a fault arc in the main circuit, the microcontroller emits a release signal, and the release circuit performs the release operation.
Overload and other protections: The main control chip MCU of the AFCI fault arc circuit breaker also detects real-time faults such as overload, leakage, under-voltage, over-voltage, and overcurrent in the main circuit, and sends fault signals to the release mechanism to disconnect the circuit, thereby implementing protection operations.